In order to realize its resource utilization, the properties of SSTS and the performance of concrete with strength grades from C30-C60, which used the mixed sand compound with SSTS and Coarse Manufactured Sand (CMS) as a fine aggregate, were investigated. The results showed that SSTS’ fineness modulus is 1.2, its clay content is 17.0% but its composition is mainly Inert Silt (IS), and SSTS replaced with 40% of the mass of CMS can obtain a mixed sand with a fineness modulus of 2.7 and a clay content of 7.0%. The morphological and filling effects of SSTS and IS will improve the workability and durability properties of concrete with no adverse effects on the compressive strength. On the other hand, clay lumps in SSTS adversely affect the workability, early cracking properties, and freeze resistance of concrete, which can be alleviated by dewatering and crushing the clay lumps in SSTS.The amount of Slurry shield tunnel slag (SSTS) from the Beijing East Sixth Ring Road renovation project is about 3 million m For the next 5 to 10 years, China’s subway construction mileage is expected to increase by over 4000 km, which will generate about 2.7 billion m3 of TS. Given that the current resource-use rate of TS in China is under 10% [To meet the rapid development of China’s economy and accelerating urbanization, many underground tunnels have been built in recent years. However, the consequent problem is that a large amount of Tunnel Slag (TS) has become an important part of construction waste . A tunne2 emissions per ton [In the early days, TS was mostly disposed of by dumping or landfilling, which can cause the following negative effects ,4,5: (a) per ton .TS properties depend on a tunnel’s geohydrological conditions, rock properties, and excavation methods, in which tunnel boring machines and drill-and-blast methods are mostly used in rock formations; their TS contains more solid rock, gravel, and stone chips, which are generally used as concrete aggregate ,9, inertIn the slurry shield tunnel construction, the slurry recycling system consists of slurry preparation, slurry adjustment, slurry transfer, and slurry–water separation . FirstlyGiven the global shortage of natural sand and gravel resources, materials other than natural aggregate should be sought, but research on the resource-use of slurry shield TS in the concrete aggregate field is insufficient. Some studies have shown that the high-value sand and stone separated from slurry shield TS can be used as concrete aggregate . HoweverThe use of SSTS as an alternative material to concrete fine aggregate, which can reduce the negative environmental impact of TS and the wastage of sand resources, will provide considerable economic, social, and environmental benefits to tunnel projects. This paper tested the physical and chemical properties of SSTS; evaluated the effects of SSTS partially replacing the mechanism sand with respect to the workability, mechanical properties, and durability of large flow concrete; and explored the feasibility of preparing large flow concrete by SSTS.Cementitious materials used in this paper consisted of cement, fly ash, and blast furnace slag with mass ratio of 6:2:2. These materials are described as follows: P.O 42.5 ordinary Portland cement with standard consistency water consumption of 27.8%, 80-μm sieve residual of 2.8%, 28-d compressive strength of 44.5 MPa, and 28-d flexural strength of 7.1 MPa; class II fly ash with 45-μm sieve residual of 13.2%, 5.65% burn-off, and 102% water demand ratio; and S95 grade blast furnace slag with 45-μm sieve residual of 4.00% and 91.9% flowability.The tunnel of the East Sixth Ring Road renovation project is located in the lower part of the alluvial fan of Yongding River and Chaobai River in Tongzhou District. The stratum along the route is mainly composed of sand layer, fine-powder sand layer, silt layer, silt clay layer, and round-gravel pebble layer interlayer deposits. Geological exploration results showed that TS contains about 40% silica–alumina sand particles.This study used two types of sand as raw materials for concrete fine aggregate, as shown in The second type of sand is granite M-S produced in Beijing, which has a fineness modulus of 2.6, loose porosity of 44%, and methylene blue value of 3.5. Mineral compositions of M-S are shown in 3, clay content 0.3%, and crushing value 5.6; aggregate with particle size of 10–25 mm has apparent density 2690 kg/m3, clay content 0.4%, and crushing value 5.4.In this paper, crushed stone with two particle sizes of 5–10 mm and 10–25 mm were formulated as concrete coarse aggregate according to a mass ratio of 4:6, as shown in The water reducer used in this research process is polycarboxylic acid water reducer provided by Beijing Shou Fa Tian Ren Ecological Landscape Co., Ltd. , with water reduction rate of 28%, and tap water from the materials laboratory of Beijing University of Civil Engineering and Architecture was used as mixing water.n = 0.4. Nevertheless, clay content of No. 3 mixed sand is 7%, which exceeds the maximum limit of 5% in GB/T14684-2011. However, properties of IS and clay mineral are relatively different. Hence, the mass ratio of 4:6 was used as the optimal ratio of SSTS to CMS compounding.Since the particle size of SSTS is mostly less than 0.60 mm, its compounding with M-S will lead to a poor gradation and to an excessive amount of powder. Hence, fine particles under 0.60 mm in M-S were screened out, and CMS with fineness modulus of 3.8 was obtained. Thereafter, CMS was replaced by SSTS according to mass ratios of 0, 20, 40, 60, 80, and 100%. Properties of each type of mixed sand are shown in As shown in Chemical compositions of SSTS, IS, and SB were tested by X-ray fluorescence (XRF) ; mineral compositions of SSTS, IS, M-S, and SB were tested by X-ray diffractometer (XRD)  with scanning speed of 5°/min and test range of 10–80°. Microscopic morphology of IS, M-S powder, and SB were characterized by scanning electron microscope (SEM) , and the particle morphology of SSTS and M-S were observed by ultra-deep field body microscopy  with magnification of 0.1× to 5000×.Workability was evaluated by the slump and expansion values according to the requirements of the Chinese national standard GB/T50080-2016 . SpecimeConcrete durability was tested according to the requirements of the Chinese national standard GB/T50082-2009 , includiFor testing the anti-chlorine ion erosion performance, after 28 days of curing in standard conditions, vacuum water saturating for 24 h, and then using the coulomb electric flux method, each group of three specimens with the size of 50 mm × 100 mm × 100 mm was evaluated using NEL-PDU type chloride ion diffusion coefficient tester.To test the water penetration resistance of concrete, six specimens were prepared for each group, and their penetration depth under water pressure after a 28-d curing at standard conditions was measured.2 concentration of 20 ± 3%, relative humidity of 70 ± 5%).The carbonation resistance was tested, after 26 days of curing in standard conditions and 48 h drying at 60 °C in an oven, via carbonizing each group of nine 100 mm × 100 mm × 100 mm cubic specimens at 3, 7, and 28 d in the carbonization chamber  as a flocculant, which can play a selective flocculation role in the cyclone process , particut-statistical tests  were used to evaluate the difference in compressive strength of each group at 28 d. The test’s null hypothesis assumed that the compressive strength of each group is equal, with a two-tailed significance level of 0.05. The null hypothesis should be rejected if The compressive and flexural strengths of the concrete are shown in t-statistical test.Note that with an increase in the strength grade, the proportions of fine aggregate particles with a particle size below 0.60 mm to the total mass of the concrete were 14.2, 12.6, 10.9, and 10.8%. Therefore, the degree of influence on the compressive strength of concrete was decreasing. That is, SSTS has an evidently adverse effect on the compressive strength of concrete when the mass ratio of SSTS to concrete mix exceeds 12.6%.According to JGJ55-2011, the 28-d designed compressive strengths of each strength grade were 38.2, 48.2, 59.9, and 69.9 MPa. Except for some DMS groups, for which the 28-d compressive strengths were slightly lower than the designed strengths, the remaining groups of concrete with cement accounted for only 60% of the mass ratio of the cementitious material required to meet the design requirements.2, which is crystalline inert, is essentially still a siliceous sand as natural sand, so there is basically no chemical reaction between IS and cementitious materials [The crystalline nucleation and activity effects of the M-S powder can play the role of a partially active admixture and increase the generation of hydration products to improve the compressive strength of concrete. Meanwhile, the silt composed of SiOaterials . Howeveraterials ,37. Meanaterials ,39.−6 − 421 × 10−6, and WMS groups showed medium drying shrinkage between M-S and DMS groups in the range of 487 × 10−6 − 399 × 10−6. However, the lowest drying shrinkages were shown in the DMS groups in the range of 469 × 10−6 − 388 × 10−6. Note that with an increase in the water–cement ratio, the drying shrinkage of concrete and the influence of fine aggregates on the drying shrinkage decreases.This study tested the 60-d drying shrinkage of concrete in a shrinkage chamber after curing for 3 d under standard curing conditions. M-S with particle size of 0.60–4.75 mm and gravel with particle size of 4.75–25.00 mm play important roles in inhibiting the shrinkage of concrete . Sand paHowever, the combination of SSTS and CMS improved the particle size distribution and filling compactness of the solid particles inside the concrete . MoreoveThe clay lumps in WMS have a porous structure, and water in their internal pores will gradually evaporate, thereby producing large shrinkage deformation. However, the clay-lump content in total concrete is extremely low. Therefore, the drying shrinkage of the WMS groups is higher than that of the DMS groups, but still less than that of the M-S groups.The results of the circular cracking test reflect the early cracking performance of the concrete. SSTS and IS with no activity effect in the DMS groups can increase the aggregate compactness and volume stability of concrete, thereby leading to less chemical and plastic shrinkage and better early cracking resistance. The active effect of the M-S powder and the large void ratio of M-S increase the chemical and plastic shrinkage of concrete at an early age; thus, there is an earlier cracking time of the concrete. The presence of a clay lump in WMS is an unstable cracking-inducing factor within the concrete. Under circumferential restraint and shrinkage stress, initial cracks in the clay lump and weak surrounding initial cracks in the concrete will develop rapidly, leading to an earlier cracking time. This result indicates that clay lumps in WMS have a substantial adverse effect on the early cracking performance of concrete.The water-penetration resistance of concrete can also indicate its penetration resistance and denseness. d is the depth of carbonation (mm), k is the carbonation rate constant, and t is the time of carbonation (min). The depth of carbonation at each age is the vertical coordinate and the square root of the carbonation time is the horizontal coordinate. Taking a linear fit to the carbonization data, the slope of the fitting result is the value of k.The carbonation depths of the concrete at 3, 7, and 28 d are shown in 2 concentration, the carbonation products of calcium carbonate and calcium silicate are generated because of the reaction of CO2 with calcium ions and the decomposition of calcium–silicate–hydrate, respectively [2 concentration and temperature, given the filling and morphological effect of SSTS and IS in DMS and WMS, we speculated that the smaller void ratio of DMS and WMS will optimize the porosity and permeability of concrete, and reduce the number of fine pores and capillaries inside concrete [ectively . Additioectively , and thiconcrete . ConsequDuring the freeze–thaw cycle, the combined water in the internal pores of concrete undergo a periodic phase change, and the expansion stress will continuously expand the original pores, resulting in new cracks and pores. As the freeze–thaw cycles are carried out, old and new cracks and pores will be further developed, causing the formation of large cracks through the concrete due to freeze expansion and surface peeling . During As shown in The Chinese national standard GB/T14684-2011 considers particles with a particle size under 75 μm as clay powder, which will have a large adverse effect on concrete performance owing to its special laminar structure. Meanwhile, IS with a particle size below 75 μm in SSTS has a limited adverse effect on concrete and even has a positive effect when mixed in the appropriate amounts.The concrete test results showed that treatment of SSTS with dewatering, the crushing of clay lumps, and compounding with CMS can solve the problems of significantly fine SSTS particles and high clay and clay lump contents. Moreover, it can be used to prepare large fluid concrete with good performance. Although the direct use of wet SSTS compounded with CMS can adversely affect workability, early cracking performance, and the freeze resistance of concrete, it can only be used in concrete element plants and project sites for the preparation of small concrete members and non-load-bearing parts of concrete. Retreatment at the tunnel site to further reduce clay content and clay lump content of SSTS can further increase its resource potential.This paper studied the physical and chemical properties of SSTS, and the performance of concrete using mixed sand compounding with SSTS and CMS as fine aggregate. The following findings can be drawn according to the previously discussed test results.An ultra-fine particle size and a high clay content are the main characteristics of SSTS. In SSTS, the chemical composition of IS with a particle size under 75 µm is similar to sand particles with a particle size above 75 µm. In addition, its mineral composition is mainly quartz, feldspar, and muscovite. Microscopic test results show that SSTS and IS have better morphological characteristics and microscopic morphology compared with M-S. The best results of compounding SSTS with CMS at a mass ratio of 4:6 can obtain mixed sand with a fineness of 2.7 and a loose porosity of 40%.By adjusting the water reducer dosage, the slump values of C30–C60 strength grade concrete using DMS, WMS, and M-S as fine aggregates can reach 230–260 mm. The morphological effect of sand particles in SSTS and the filling and micro-roller effects of IS can significantly improve the aggregate void ratio, reduce friction between the mortar and aggregate and the water reducer dosing, and improve the workability of the concrete mixture. Clay lumps in WMS will increase water reducer dosing and the cohesion of concrete, and treatments involving dewatering and the crushing of clay lumps in SSTS can significantly improve this shortcoming.Given that SSTS and IS improve the pore structure of concrete and the spatial network structure of cementing materials, the 28-d compressive strength can meet the design requirements of the C30–C60 strength grade. The compressive strength of the M-S group concrete is slightly higher than those of the DMS and WMS groups, while the flexural strength and toughness of the DMS and WMS groups are superior. Moreover, the drying shrinkage, chloride ion erosion resistance, water penetration resistance, and carbonation resistance are better than in the M-S groups of concrete. Lastly, clay lumps in the WMS group causes an early cracking resistance and frost resistance lower than those resistances in the DMS and M-S groups.


Enterobacter cloacae complex (CREC) by whole-genome sequencing and to explore its clinical characteristics.To analyze the molecular epidemiology of carbapenem-resistant Enterobacter cloacae complex isolates collected in a tertiary hospital during 2013–2021 were subjected to whole-genome sequencing to determine the distribution of antimicrobial resistance genes (ARGs), sequence types (STs), and plasmid replicons. A phylogenetic tree of the CREC strains was constructed based on the whole-genome sequences to analyze their relationships. Clinical patient information was collected for risk factor analysis.blaNDM-1  was the main carbapenem-hydrolyzing β-lactamase (CHβL), followed by blaIMP-4 . Several other extended-spectrum β-lactamase-encoding genes were also identified, with blaSHV-12  and blaTEM-1B  being the predominant ones. Multi-locus sequence typing revealed 25 distinct STs, and ST418  was the predominant clone. Plasmid analysis identified 15 types of plasmid replicons, among which IncHI2  and IncHI2A  were the main ones. Risk factor analysis showed that intensive care unit (ICU) admission, autoimmune disease, pulmonary infection, and previous corticosteroid use within 1 month were major risk factors for acquiring CREC. Logistic regression analysis showed that ICU admission was an independent risk factor for CREC acquisition and was closely related with acquiring infection by CREC with ST418.Among the 51 CREC strains collected, BlaNDM-1 and blaIMP-4 were the predominant carbapenem resistance genes. ST418 carrying BlaNDM-1 not only was the main clone, but also circulated in the ICU of our hospital during 2019–2021, which highlights the necessity for surveillance of this strain in the ICU. Furthermore, patients with risk factors for CREC acquisition, including ICU admission, autoimmune disease, pulmonary infection, and previous corticosteroid use within 1 month, need to be closely monitored for CREC infection. Enterobacter cloacae complex (ECC), which belongs to the family Enterobacteriaceae, is a common nosocomial pathogen responsible for several human infections, including bacteremia and respiratory tract, wound, and urinary tract infections  has posed a serious public health threat (Enterobacter cloacae complex (CREC) is the third most common CRE following Escherichia coli and Klebsiella pneumoniae in China , among which KPC, NDM, VIM, IMP, and OXA-48 are the most prevalent ones. In addition, overexpression of the β-lactamase AmpC, the occurrence of extended-spectrum β-lactamases (ESBLs), such as TEM, CTX-M, and SHV, membrane-associated mechanisms, such as outer membrane permeability, and the overexpression of efflux pumps have been demonstrated to contribute to carbapenem resistance in ECC . The acqA multinational surveillance study based on multi-locus sequence typing (MLST) revealed substantial clonal diversity of CREC, and ST114, ST93, ST90, and ST78 were potential high-risk clones globally widespread in 37 countries . Risk faThe present study was performed in Nanjing Drum Tower Hospital, a 3800-bed tertiary hospital. A total of 51 CREC strains collected during 2013–2021 were subjected to whole-genome sequencing (WGS) to analyze the distribution of antimicrobial resistance genes (ARGs), sequence types (STs), and plasmid replicons. Clinical patient information was collected to analyze risk factors for CREC acquisition. We attempted to systematically analyze the molecular epidemiology and clinical characteristics of CREC infection to provide evidence for effective control of nosocomial infection with CREC.In total, 51 consecutive, non-duplicate CREC isolates were collected in Nanjing Drum Tower Hospital  during 2013–2021. All the strains were verified by Vitek 2.0  and matrix-associated laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) . And these strains were confirmed as CREC by testing the susceptibilities to imipenem by n = 16, 31.4%), abdominal dropsy , blood  secretion , urine , catheter , pleural effusion , and bronchial alveolar lavage fluid . The numbers of strains isolated in each year were as follows: 2013 , 2014 , 2015 , 2016 , 2017 , 2018 , 2019 , 2020 , and 2021 . The CREC isolates were mostly collected from the ICU , surgical ward , cardiac surgery ward , hematology ward , and respiratory ward .The strains were isolated from the following samples: sputum . Scaffolding was performed using SSPACE standard version 3.0 and gaps within scaffolds were closed using GapFiller  for genomic DNA extraction using the Ultraclean Microbial DNA Isolation Kit  according to the manufacturer’s recommendations. After a quality check, the genomic DNA samples were sent to Beijing Tiangen Biochemical Technology  for sequencing on the MiSeq platform . After quality trimming (Qs ≥ 20), apFiller . The ass1 with the accession number PRJNA868583 and are publicly available. MLST of strains retrieved from GenBank was performed using MLST v2.0.2 ARGs were identified using Resfinder v2.1.3 Antibiotic resistance plasmid genes were analyzed by uploading the genomes to PlasmidFinder v2.1.4Genomes of 51 CREC isolates have been uploaded to the NCBI BioProject repositoryE. hormaechei strains were annotated using Prokka v1.14.6 (The genome sequences of  v1.14.6 . The gff v1.14.6 . The nuc v1.14.6 . A maxim v1.14.6  and was  v1.14.6 .Enterobacter cloacae (CSEC) collected during the same time period and in the same wards and anatomical sites were included as a control group. The following factors were analyzed: patient demographics, underlying diseases and acquired infections, invasive procedures during hospital stay, and treatments within 1 month  was conducted for statistical analysis. The results of univariate analysis were reported as analysis . P < 0.0Enterobacter hormaechei, three (5.9%) as Enterobacter kobei, two (3.9%) as Enterobacter cloacae, and the two (3.9%) as Enterobacter asburiae  isolates were identified as asburiae .Various genes conferring resistance to 12 antimicrobial agents were identified in the 51 CREC isolates .blaCHβls were identified; blaNDM-1  and blaIMP-4  were the predominant ones, followed by blaIMP-26 , blaNDM-5 , and blaKPC-2 . Of note, co-existence of blaNDM-1 and blaIMP-4 was detected in six isolates . Co-existence of blaNDM-1 and blaKPC-2 was detected in one isolate, EC13565. As for blaESBLs, blaSHV-12 , blaTEM-1B , blaCTX-M-3 , blaCTX-M-9 , blaOXA-1  and blaCTX-M-14, blaCTX-M-162, and blaTEM-1A  were identified (Five entified .blaACT with blaACT-7 being the predominant one (mcr)-9  was highly prevalent among the CREC isolates in this study  was the most prevalent, followed by ST171 , ST97 , ST78 , ST182 , ST93 , ST252 , ST1001 , and ST1373 . The remaining STs were only detected in one isolate .n = 33, 64.7%) and IncHI2A  were the most prevalent ones, followed by IncX3 , IncFIB , IncN , and Col (pHAD28) . The remaining plasmid replicons were relatively less common (Fifteen types of plasmid replicons were identified in 98% (50/51) of the isolates: IncHI2  was an independent risk factor for CREC acquisition (P = 0.045) correlated with CREC acquisition with ST418 as compared to CREC acquisition with non-ST418 strains.The results of the comparison of clinical variables between the CREC and CSEC group are presented in uisition . The resThe wide spread of the CREC poses a serious public health threat. Therefore, it is urgent to characterize the molecular epidemiology of CREC and risk factors for CREC acquisition to provide more information for guiding the formulation and implementation of infection control measures. In this study, we used WGS technology to analyze the genomic characteristics of clinical CREC isolates collected over a 9-year period in a tertiary hospital in Southeast China. To the best of our knowledge, this is the first study to analyze the genomic epidemiology and potential risk factors for acquisition of CREC isolates collected in Jiangsu Province, China.blaNDM-1 was the predominant blaCHβL, which is in accordance with the results of a multicenter study conducted in 11 Chinese cities that provided evidence that blaNDM-1 is the main CHβL conferring resistance to carbapenem   and fromC strain , highliglaIMP-15 ; E. hormn France ; E. horm Denmark ; And co-in China .blaKPC-3 on the IncFIA plasmid  can be found in the article/The studies involving human participants were reviewed and approved by the Ethics Committee of Nanjing Drum Tower Hospital . Written informed consent from the participants’ legal guardian/next of kin was not required to participate in this study in accordance with the national legislation and the institutional requirements.MH performed the bioinformatics analysis and wrote the manuscript. CL interpreted the data on the ARGs and plasmid replicons and revised the manuscript. HX sorted the data and helped with manuscript writing. JZ and YZ interpreted the data on the ARGs and plasmid replicons. CCL performed the statistical analysis. HS and XC designed the study and revised the manuscript. All authors read and approved the final manuscript.


The concrete jacketing method for retrofitting old reinforced concrete (RC) columns should secure confinement and seismic performance under torsion as well as unidirectional later loads. In a previous study, a hybrid concrete jacketing method was proposed using steel wire mesh (SWM), steel grid reinforcement (SGR), which can replace reinforcement of existing concrete jacketing method, and using steel fiber non-shrinkage mortar (SFNM). These details can simplify the retrofitting process of the existing concrete jacketing method, and seismic performance was evaluated by conducting a cyclic loading test under unidirectional loading. In this paper, the torsional behavior of RC columns retrofitted with the hybrid concrete jacketing method was investigated. Four specimens were fabricated and conducted cyclic loading tests under two types of loading schemes, unidirectional and bidirectional loading, to examine the effect of the loading path. The strength and energy dissipation capacity of retrofitted columns with hybrid concrete jackets increased approximately eight times compared to the old RC columns under torsional loading. Therefore, the hybrid concrete jacketing method can improve torsional resistance. Irregular buildings in which the rigidity or strength of a structural system is distributed discontinuously, horizontally, and vertically can experience seismic torsion due to discontinuity in the shape of the building and loading path. Many studies focused on the torsional behavior of reinforced concrete (RC) columns under combined load ,2,3. TirTo improve the seismic performance and ensure easy construction of the existing concrete jacketing retrofit method without interface treatment, a hybrid concrete jacketing method was proposed to strengthen the non-seismic RC columns . The hybThis study was focused on the evaluation of the torsional behavior of the hybrid concrete jacketing method under the combined load of compression, including a bending and torsional moment. The experimental results were used to verify the seismic performance and confinement effect of the hybrid concrete jacketing method in torsional loading.(1)The strength of the new concrete must be greater than that of the old concrete.(2)The minimum thickness of the jacket should be 100 mm on each side, and four longitudinal reinforcements should be arranged at least.(3)The spacing of the stirrup should be less than 200 mm or the thickness of the jacketing section and less than 100 mm in the plastic hinge region of the column.(4)The dust should be removed as the preparation of the concrete surface before jacketing.Four reinforced concrete columns, including two old columns  and two retrofitted columns , were fabricated. The loading scheme used variables to investigate the effect loading path. Old columns with non-seismic details had 250 mm × 250 mm cross sections and were 1800 mm tall. The concrete jacketing section was designed according to Pennelis and Kappos . The recThe sizes of retrofitted specimens were 500 mm × 500 mm, which had 250 mm thickness of the concrete jacketing section. Details of the specimens are shown in Concrete with compressive strengths of 24 MPa was used for columns and upper beams. SFNM was used in the retrofitted specimens, which can be expected to control cracks caused by the shrinkage of concrete and coarse aggregates. Adding steel fibers can reduce the brittleness of concrete. The steel fiber content and shapes, such as straight, hooked-end, crimped, and twisted, affect its performance. Low fiber content (<1%) is generally used in plastic shrinkage crack control with minimal strength enhancement. Medium fiber content (1–2%) provides suitable workability for cast-in-place. High fiber content (>2%) can provide exceptional mechanical properties . In addiThe detail of loading setup and loading protocol was referred to that of previous study . DetailsThe cracks and failure patterns of each specimen at the end of the test are depicted in The comparison of crack propagation between the non-retrofitted column and the concrete-jacketed column is summarized in In the retrofitted specimens using the hybrid concrete jacketing method, fewer cracks occur than in the non-retrofitted specimens, regardless of the loading scheme. It is indicated that the hybrid concrete jacketing method can effectively resist torsion and shear.To compare the maximum load and drift ratio for each specimen, the skeleton curves are shown in The maximum load and displacement of SFU were 9.2 times and 1.9 times that of NSU, respectively. In addition, the maximum load and displacement of SFB were 7.4 times and 1.1 times that of NSB, respectively. There was no dramatic reduction in the retrofitted specimens in any of the loading schemes because the hybrid concrete jacketing method can effectively resist improving the seismic performance of the old columns.A cyclic loading test was conducted considering the combination of bending, shear, and axial load, which can generate torsion due to structural irregularity. The effect of the applied loading scheme on the column and the performance of the retrofit method were analyzed in terms of the relationship between the torsional moment and the twist. The torsional moment and twist are calculated by Equations (1) and (2). The torsional moment and twist were obtained from LVDTs and strain gauges.Here, All torsional moments were calculated using the first cycle, which recorded the maximum load of that drift ratio. The torsional moment-twist envelopes are shown in The concrete jacketing method has advantages for improving the strength and stiffness of old columns. He et al.  expresseEnergy dissipation capacity is one of the most important indicators to evaluate the seismic performance of structures. Energy dissipation was typically estimated by calculating the area enclosed by the hysteresis loop for each cycle, as shown in The comparison of the cumulative energy dissipation capacity of each specimen is shown in (1)In the case of specimens under unidirectional loading, more significant shear cracks and concrete spalling occurred than that in specimens under bidirectional loading. These results indicated that flexural and torsional moments generated by combined load decreased as the axes of the lateral and axial loads of the bidirectional loading coincided. In the retrofitted specimens using the hybrid concrete jacketing method, fewer cracks occurred than in the non-retrofitted specimens, regardless loading scheme. It is indicated that the hybrid concrete jacketing method can effectively resist torsion and shear.(2)The maximum load of SFU was about 9.2 times larger than NSU, and that of SFB was 7.4 times larger than NSB. In addition, the hybrid concrete jacketing method increased the cumulative energy dissipation capacity by approximately 7.7 times compared to the old RC columns under unidirectional loading, in which more torsion is induced. Therefore, the hybrid concrete jacketing method can effectively provide torsional resistance without the complex retrofitting process in the existing concrete jacketing method.(3)For all specimens, the response was linear with increasing applied torsional moment until the initial crack occurred. The torsional moment of SFU was about 4.1 times larger than NSU, and that of SFB was 4.8 times larger than NSB. In the case of NSU and NSB, the increasing rates of the torsional moment from the initial cracking to the maximum torsional moment were 30% and 53%, respectively, and that of SFU and SFB were 68% and 67%, respectively. For torsional stiffness attenuation, the hybrid concrete jacketing method improved the initial torsional stiffness of the RC column subjected to unidirectional load 12 times, and in the case of specimens subjected to unidirectional load, retrofitted specimens were 10 times that of the non-retrofitted column. The torsional stiffness of the non-retrofitted specimens rapidly decreased after the maximum torsional moment was reached due to concrete spalling. This indicated that the hybrid concrete jacketing method could significantly enhance the torsional capacity.This study investigated the torsional behavior of retrofitted RC columns using the hybrid concrete jacketing method under combined loading. Two non-retrofitted RC column specimens and two retrofitted specimens were fabricated, and cyclic loading tests were conducted. Two types of loading schemes were applied to simulate actual seismic load. The following conclusions have been drawn:


We surveyed antimicrobials used in Greek pediatric hematology–oncology (PHO) and bone marrow transplant (BMT) units before and after an intervention involving education regarding the 2017 clinical practice guidelines (CPG) for the management of febrile neutropenia in children with cancer and hematopoietic stem-cell transplant recipients.Antibiotic prescribing practices were prospectively recorded between June 2016 and November 2017.In December 2017, baseline data feedback was provided, and CPG education was provided. Prescribing practices were followed for one more year. For antibiotic stewardship, days of therapy, and length of therapy were calculated.Five of the 6 PHO units in Greece and the single pediatric BMT unit participated.Admitted children in each unit who received the first 15 new antibiotic courses each month.Administration of ≥4 antibiotics simultaneously and administration of antibiotics with overlapping activity for ≥2 days were significantly more common in PHO units in general hospitals compared to children’s hospitals. Use of at least 1 antifungal was recorded in ∼47% of the patients before and after the intervention. De-escalation and/or discontinuation of antibiotics on day 6 of initial treatment increased significantly from 43% to 53.5% (P = .032). Although the number of patients requiring intensive care support for sepsis did not change, a significant drop was noted in all-cause mortality (P = .008).We recorded the antibiotic prescribing practices in Greek PHO and BMT units, we achieved improved prescribing with a simple intervention, and we identified areas in need of improvement. This issue is particularly important for children with cancer, who frequently require antibiotics during periods of febrile neutropenia.The overuse of antimicrobials, the emergence of antimicrobial resistance worldwide, and increasing healthcare-associated costs have shown the importance of maximizing the application of antibiotic stewardship programs (ASPs), which help to maintain the efficacy of currently existing antibiotics and lead to substantial cost savings. but such measures have not been studied extensively. The few published studies have shown that in hematology–oncology units, antibiotic de-escalation and discontinuation can be safely implemented. For example, a clinical trial in 6 academic hospitals in Spain showed that in adults with hematological malignancies, high-risk febrile neutropenia, and negative blood cultures, empirical antimicrobial therapy can be safely discontinued after 72 hours of apyrexia and clinical recovery irrespective of the absolute neutrophil count (ANC).In pediatric hematology–oncology (PHO) units, evidence-based use of antibiotics and antibiotic de-escalation strategies have the potential to decrease unnecessarily prolonged use of broad-spectrum antibiotics,In Greece, nearly 300 pediatric oncology patients aged 0–14 years are diagnosed annually. Additionally, ∼12 children with nonmalignant diseases require hematopoietic stem cell transplantation (HSCT) annually. There are 6 PHO units in Greece: 3 units in Athens, 2 units in Thessaloniki, and 1 unit in Heraklion. In addition, there is a single pediatric bone marrow transplant (BMT) unit in Athens. All PHO units in Athens are in children’s hospitals, and the units in Thessaloniki and Heraklion are in general university hospitals. The goals of this study were to describe the use of antibiotics in hospitalized children with cancer and pediatric HSCT recipients in Greece and to evaluate the impact of a simple multifaceted intervention on prescribing practices.Since 2016, as part of the project Preventing Hospital Infections in Greece (PHIG), the Center for Clinical Epidemiology and Outcomes Research (CLEO) has been monitoring the use of antimicrobials in Greek PHO units.Of the 6 PHO units in Greece, 5 of these units and the country’s single pediatric BMT unit participated in this project. Beginning at the end of June 2016, all participating units prospectively recorded the first 15 children admitted per month who required the initiation of new antibiotics for treatment or prophylaxis. Ethics approval was obtained from the institutional review boards of all participating hospitals.Children who had already been on intravenous antibiotics the day before the initiation of the new antibiotic regimen were excluded. Administration of any antifungal therapy in a child with febrile neutropenia was recorded as empirical therapy. No pediatric patient was recorded twice within the same month, and the form was completed for the first 7 days of antibiotic administration.We collected the following data: age and sex, presence of central lines, type of underlying disease , ANC and its relation to the first day of antibiotic therapy, antibiotics used and their indication , cultures obtained, pathogens isolated, presence or absence of invasive fungal disease, and clinical outcome . The time frame and the goals of the PHIG intervention are shown in Figure  For febrile neutropenia, the definition of the Infectious Diseases Society of America (IDSA) was used.In December 2017, a meeting between CLEO representatives and the directors of all PHO units took place. A baseline data analysis and the main conclusions were presented. Finally, the goal of implementing the International Pediatric Fever and Neutropenia Guideline Panel’s clinical practice guidelines (CPGs) for the management of febrile neutropenia in children with cancer and HSCT recipients, which had recently been updated, was also discussed. In all participating units, a feedback report was sent every 6 months throughout the study period to inform each unit about its specific progress with respect to the implementation of the CPGs.Surveillance of antibiotic use and the implementation of the CPGs started in December 2017 in 5 of the units. In one unit, surveillance and intervention started in March 2018 due to local resource restrictions; another unit, due to limited resources, participated in data collection only during the pre-intervention period (June 2016 to November 2017). The same demographic and clinical data were recorded in the 2-year postintervention period (January 2018–December 2019) to compare antimicrobial use before and after implementation of the CPGs. One DOT represents the administration of a single antibiotic on a given calendar day, even if multiple doses are given on that day. The number of days a patient is receiving antibiotics, regardless of the number of different agents administered, constitutes LOT. We compared data for the following factors: (1) administration of ≥4 antibiotics simultaneously, (2) use of antibiotics with overlapping antimicrobial activity for ≥2 days, (3) de-escalation or discontinuation with negative cultures by day 6, (4) start of antibiotics without obtaining cultures, (4) antibiotic initiation without a clear source or fever and with ANC > 500/μL, (5) use of standard versus other nonstandard regimens for empirical therapy , (6) early use of antifungals before day 4 of fever, (7) number of patients admitted for sepsis to ICU, and (8) number of deaths before and after the PHIG intervention.For the purposes of antibiotic stewardship, we calculated days of therapy (DOT) and length of therapy (LOT). tests of independence and Mann-Whitney U tests were performed, as appropriate. Stratified analysis by unit and type of unit was also performed. All reported P values were based on 2-sided tests, and statistical significance was set at P < .05. All statistical analyses were performed with Stata version 13.0 software .Nominal variables are presented with absolute and relative (%) frequencies, whereas continuous variables are presented with medians and interquartile ranges. To evaluate differences between units and the effect of the intervention, χP = .001).Demographic and clinical characteristics of recorded cases by PHO unit and location in a children’s or general hospital are shown in Table Patient and antibiotic days, LOT per 1,000 patient days, DOT-to-LOT ratios, and most used antibiotics during the study period by PHO unit and by type of hospital  are shown in Table P = .001 for both). The overall administration of antibiotics with overlapping activity for ≥2 days did not change significantly . This rate decreased from 3.5% to 2.1% in units in children’s hospitals but increased from 6.7% to 12.5% in units in general hospitals. Again, the pre- and postintervention comparisons of the administration of antibiotics with overlapping activity for ≥2 days between units by type of hospital were highly significant . Notably, all study goals improved in unit 2 after the intervention . For all units combined, antibiotic therapy was started without obtaining cultures less frequently after the intervention . This practice was more frequent in PHO units in general compared to children’s hospitals before the intervention  and after the intervention .The antibiotic use rates on day 1 of febrile neutropenia before and after the PHIG intervention are shown in Supplementary Table S1. Major differences in practice existed between different units prior to intervention. In units 1 and 2, triple antibiotic therapy  was commonly practiced. In the BMT unit, monotherapy with an antipseudomonal β-lactam was more commonly used. In unit 5, double gram-negative coverage was used, and in unit 6, triple antibiotic therapy and other nonstandard regimens were frequently used. Significant improvements in antibiotic prescribing were noted after the intervention (P = .032). This rate of discontinuation increased from 53.1% to 60.2% in units in children’s hospitals and from 15.1% to 28.3% in units in general hospitals.In cases of negative blood cultures in patients receiving antibiotics with gram-positive coverage and/or a second antibiotic with gram-negative coverage, de-escalation and/or discontinuation of antibiotics on day 6 in all units significantly increased from 43% to 53.5% (P = .198). In PHO units in children’s hospitals, this rate decreased from 3.7% to 3%, and in PHO units in general hospitals, this rate decreased from 5% to 3%.Antibiotic initiation without a clear infectious source or fever and with ANC >500/μL occurred during the preintervention period in 4.1% of antibiotic courses and in the postintervention period in 3% of antibiotic courses (P = .001) and remained so after the intervention (P = .001). Furthermore, triple antibiotic therapy decreased in units 1 and 2; monotherapy with an antipseudomonal β-lactam decreased in the BMT unit; and triple antibiotic therapy and nonstandard antibiotic combinations decreased in unit 6.The overall use of nonstandard antibiotic regimens was not significantly different after the intervention (11.9% before vs 12.7% after). However, the use of nonstandard antibiotic regimens was significantly more frequent in PHO units in general hospitals than in children’s hospitals prior to the intervention (P = .893). Almost all patients treated in the BMT unit were receiving at least 1 antifungal medication at the time of data collection. Almost 66% of children treated in units in general hospitals were receiving at least 1 antifungal medication, compared with ∼25% of patients treated in units in children’s hospitals. Overall, the use of at least 1 antifungal medication was significantly more common in PHO units in general versus children’s hospitals before the intervention  and remained so after the intervention .The use of antifungals in PHO units before and after the PHIG intervention is shown in Supplementary Table S2. Overall, 47.4% of patients before the intervention and 46.9% after the intervention received at least 1 antifungal medication (P = .781). We noted a significant decrease the number of deaths in all PHO units combined: 36 deaths (4.29%) before the intervention versus 21 deaths (2.13%) after the intervention (P = .008).The number of patients requiring ICU support for sepsis did not change significantly: 18 patients (2.13%) before intervention versus 23 patients (2.33%) after the intervention  is unjustified. Apart from children with acute myeloid leukemia, refractory, or relapsed acute lymphoblastic leukemia, Burkitt lymphoma, and exposure to high-dose corticosteroids, most children with cancer do not require prophylaxis or therapy with antifungal agents. A multicenter randomized controlled trial in Italy showed that empirical antifungal therapy was of no advantage in terms of survival without fever and invasive fungal disease in children who were defined as low risk for systemic fungal disease.The use of antifungals on days 1–4 of fever is contrary to international guidelines,Our study had several strengths and limitations. This was the first study to prospectively collect data regarding antibiotic use in Greek PHO units. Although one PHO unit did not participate and another did not collect data during the postintervention period, our data are representative of the inpatient antibiotic prescribing practices for children with cancer and HSCT recipients treated in specialized units in Greece. One limitation of the study is that only hospital-wide and not unit-specific antibiotic susceptibility data for bacterial pathogens were available. Hence, we could only speculate about the reasons for the considerably different antibiotic prescribing practices among units. Lower susceptibility rates of microbial pathogens may be the reason for the more aggressive use of antibiotics in general hospitals with PHO units, but this issue needs further research. Finally, we were unable to separate all-cause from infectious mortality.In conclusion, we used surveillance data to describe prescribing practices in Greek PHO and BMT units. We implemented a simple intervention that was associated with improved prescribing practices. We also identified areas necessitating improvement. As a next step, an active intervention with designated antibiotic stewardship physicians and prospective audit-and-feedback recommendations at each Greek PHO unit is needed.


P = 0.002). There was no correlation between the concentrations of PGL and morphine (from heroin) in the heroin users (P = 0.95), and the amount of heroin (morphine) consumed was not dependant on whether PGL was consumed or not (P = 0.98). The prevalence of anti-depressants, benzodiazepines, methadone and non-heroin-related opioids was seen to be significantly higher in heroin users that were positive for PGL than the control-heroin users . This study suggests that heroin users are using greater amounts of PGL compared to non-heroin users; however, the magnitude of the difference in use may not be sufficient to conclude that heroin users are at substantially greater risk of PGL toxicity compared to non-heroin users. Results indicate that heroin users who take PGL are more likely to use multiple depressant drugs, hence increasing the risk of multi-drug toxicity and death in this population.Pregabalin (PGL) is a gabapentinoid used to treat epilepsy, neuropathic pain and generalized anxiety disorder. PGL is also misused by heroin users as it enhances the effects of heroin. While it is thought those who misuse PGL take it in amounts greater than the recommended therapeutic dose, it is unknown whether there is a significant difference between the amounts of PGL used by heroin users compared to non-heroin users. This study hypothesized that the PGL concentrations in postmortem (PM) samples taken from heroin users positive for PGL would be higher than those in non-heroin users. Between 1 January 2016 and 31 December 2016, a routine drug screen and a specific screen for PGL were carried out on femoral-vein bloods from 3,750 PM Coroners’ cases. Of the cases screened, 354 were heroin users, of which 264 cases were negative for gabapentinoids and therefore used as the control-heroin-user group. PGL was positive in 229 cases, of which 69 were heroin users and 160 were non-heroin users. On comparing the PGL concentrations, statistically higher concentrations were observed in the heroin users compared to non-heroin users ( PGL is operties .PGL was originally thought to have limited potential for misuse . HoweverOut of the drug-user population, heroin users and the prison population have the highest tendency for PGL abuse , 8–11. HWhen heroin (diacetylmorphine) is ingested, it is rapidly metabolized to 6-acetylmorphine and then morphine. Due to the rapidity of heroin metabolism, generally, it is the morphine that is detected in biological matrices. Morphine is known to inhibit the gag reflex and to cause major respiratory and central nervous system (CNS) depression, which are the main causes of death among the heroin-user population . SimilarMany studies have reported a rise in PGL abuse , 16 and n = 316), with 91% of those abusing PGL being positive for opioid (n = 43) with opioid being present in every PGL-positive case; morphine from heroin use was the third most common opioid detected (n = 93) found that the PGL concentrations detected ranged from <0.6 to 182 µg/mL, with ∼40% of the cases being positive for an opiate  and ∼65% positive for an opioid (n = 209), with opioids being the most common additionally detected drugs  to determine if the heroin users who used PGL consumed different amounts of heroin compared to those who did not use PGL. Concomitant detection of other drugs observed was also investigated between the groups. This study is a follow-up of a previous study conducted by the authors using the same PM population .The Toxicology Unit at Imperial College London performs toxicological analysis on PM samples submitted by pathologists on behalf of Coroners. Coroners’ jurisdictions covered by the Unit include seven of the eight jurisdictions in London and areas in the South East of England, covering ∼15% of England’s population.Based on the request by the pathologist and consideration of the case history and samples submitted, PM analyses may include a routine toxicological drug screen of blood for prescribed, over-the-counter and controlled drugs using a basic liquid–liquid extraction ) , measurePermission was obtained from the relevant Coroners to specifically screen for PGL on PM cases where femoral-vein blood was submitted from all deceased aged ≥16 years. This study commenced on 1 January 2016 and ended on 31 December 2017.A simple protein precipitation method was used to screen/quantify PGL in femoral-vein blood. PGL and its deuterated analog  were extracted from 100 μL of blood using a single addition acetonitrile protein precipitation reaction. Analysis was performed using liquid chromatography–tandem mass spectrometry. The assay was linear from 0.5 to 50.0 μg/mL. A PGL concentration of ≥ 0.5 µg/mL was recorded as positive finding. All positive samples were quantified accurately in duplicate .6, were extracted from 1 mL of PM femoral-vein blood using cation exchange SPE cartridges . Endogenous water-soluble compounds and lipids were removed from the cartridges using deionized water, followed by a solvent mix of hexane:propan-2-ol (1:2) and then methanol. Samples were then eluted using a solvent mix of chloroform:propan-2-ol:ammonia (80: 20: 2), concentrated under nitrogen and then derivatized using N-methyl-N-trimethylsilyltrifluoroacetamide. One microliter of each sample was then analyzed by GC--MS  using an Rxi-5 MS column for chromatographic separation . The initial oven temperature was set at 120°C that was raised to 310°C at the rate of 10°C/minute; the end temperature was held for 5 minutes giving a total run time of 24 minutes. The instrument was set to the electron impact-selective ion monitoring mode, monitoring m/z 429, 236, 196 and 435, 420, 421 for morphine and morphine-d6, respectively. The assay was linear from 0.01 to 1.00 µg/mL  and intra-day (n = 6) and inter-day (n = 9) imprecision (%RSD) were less than 5% for morphine. Both limit of detection and quantification were set at 0.01 µg/mL. This method has been used routinely by the unit for over 10 years.In all cases that screened positive for morphine, the morphine was accurately quantified in duplicate using a fully validated in-house opioids method . This method is a modification of a previously published method for buprenorphine in blood . MorphinTo be placed in the “heroin-user” group, it was essential for the deceased to be positive for morphine in their blood or urine. The deceased also required an additional heroin-related compound  to be present or the case history had to strongly demonstrate heroin use . All cases that did not fall within the heroin-user group were categorized as “non-heroin users”.To compare the concentrations of PGL in heroin users to non-heroin users, the cases that screened positive for PGL were subcategorized into heroin users and non-heroin users. The distribution of PGL concentrations was then compared between the two categories to determine if a significant difference was observed. Demographics and other toxicological findings were explored in both categories.To determine if the amount of PGL used was related to the amount of heroin used, the PGL concentrations were plotted against the corresponding morphine concentrations (from heroin use) in the heroin users.A “control-heroin user” was defined as a heroin user who had screened negative for PGL and gabapentin. The distribution of morphine concentrations in the heroin users that were positive for PGL was compared to the morphine concentrations in the control heroin user group. Demographics and the concomitant detection of other drugs were also compared.All statistical analysis was carried out using IBM SPSS Statistics version 23.0 . Descriptive statistics were used to determine if the data were skewed or not, and parametric and non-parametric statistical analyses were used accordingly.P value < 0.05 was considered significant. Pearson’s Chi-squared test (χ2 test) was applied to evaluate how likely it was that any observed differences in the prevalence of other drugs/drug groups between the heroin users positive for PGL and the control-heroin users arose by chance. An outlier concentration was defined as a concentration 1.5 times the interquartile range (IQR) of the concentrations distribution. An extreme outlier concentration was a concentration that was 3 (or more) times the IQR.The Mann–Whitney U test was performed to test significance when the distribution was skewed. To determine if there was a correlation between the morphine and PGL concentration in heroin users, Spearman’s rank test (two-tailed) was used. A P = 0.81) in the distribution of PGL concentrations between males  and females .Between 1 January 2016 and 31 December 2017, the cohort consisted of 3,750 deceased. The cohort was predominantly male, containing 2,662 (71%) males and 1,088 (29%) females. 3,396 cases were non-heroin users, 354 were heroin users, of whom 264 cases were control-heroin users. Out of the 3750 cases screened, 229 were positive for PGL. The PGL concentrations in PM femoral-vein bloods ranged from 1 to 540 µg/mL ). The Mann–Whitney U test showed no significant difference (n = 160), 98 (61%) were male aged between 17 and 82 years (median = 45 years) and 62 (39%) were female aged between 16 and 91 years (median = 48 years). A two-tailed t-test showed no statistical difference between the age ranges for males and females, in the heroin users (P = 0.33) and the non-heroin users (P = 0.49).Of the 229 cases that screened positive for PGL, 69 (30%) were heroin users and 160 (70%) were non-heroin users. The proportion of male and female subjects, in both groups, were broadly consistent with the proportion for the whole cohort. Of the heroin users, 56 (81%) were male aged between 20 and 68 years (median = 44 years) and 13 (19%) were female aged between 23 and 53 years (median = 44 years). Of the non-heroin users (n = 69), the two most common drug groups observed were cocainics with 55 (79.7%) cases, followed by anti-depressants with 39 (56.5%) cases. The two most common drug groups observed in the non-heroin users (n = 160) were anti-depressants with 107 (66.9%) cases, followed by non-heroin-related opioids with 89 (55.6%) cases. PGL was observed alone (no ethanol or other drugs) in only three cases (non-heroin users). In each of those cases, the PGL concentrations fell within therapeutic ranges seen in ante-mortem plasma . Inn = 69) ranged from 1 to 540 µg/mL (median = 8.0 ± 74.2 SD) and from 1 to 168 µg/mL (median = 5.5 ± 21.0 SD) in the non-heroin users (n = 160) (see P = 0.012).The PGL concentrations in the heroin users (160) see . There wSix outlier concentrations were present in the heroin users (41–540 µg/mL) and 14 in the non-heroin users (31–168 µg/mL) see . These on = 67), with the median concentration (50th percentile) at 8 µg/mL and 75th percentile at 16 µg/mL. In the non-heroin users (n = 149), the PGL concentrations ranged from 1 to 114 µg/mL (±11.7 SD) with the median concentration (50th percentile) at 5 µg/mL and 75th percentile at 11 µg/mL (see inset in P = 0.002).The case histories of the outliers were investigated to identify cases where there was a strong suggestion of intentional drug overdose, such as empty blister packets, suicide notes, tablet residues in cups at the scene, etc., or where the toxicology result showed extreme overdose concentrations of other drugs present. Two such cases were identified in the heroin-user category and 11 in the non-heroin users. These putative intentional overdose cases were removed from the dataset, and the remaining data were then reanalyzed. In the remaining cases, the PGL concentration ranged from 1 to 117 µg/mL (±19.3 SD) in the heroin users (n = 67) and the corresponding morphine concentrations from the same blood sample  (P = 0.95). Nine PGL-positive heroin users were negative for morphine in the blood but positive for morphine and heroin-related compounds in the urine.Spearman’s rank test showed no statistically significant association between the PGL concentrations (range = 1–117 µg/mL) in the PM bloods of heroin users (n = 69), 56 (81%) were male aged between 20 and 68 years, (median = 44 years) and 13 (19%) were female aged between 23 and 53 years (median = 44 years). Of the control-heroin users (n = 264), 223 (84%) were male aged between 16 and 71 years (median = 40 years) and 41 (16%) were female aged between 24 and 69 years (median = 48 years).Of the heroin users that were positive for PGL  and the control-heroin users  (P = 0.98 using a Mann–Whitney U test).There was no statistically significant difference in the distribution of morphine concentrations between PGL positive heroin users (n = 69) and the control-heroin users (n = 264), respectively. However, the anti-depressants (57 and 19%), benzodiazepines (51 and 16%), methadone (45 and 25%), non-heroin-related opioids (33 and 8%) and anti-psychotics (22 and 6%) were present at higher percentages in heroin users positive for PGL compared to the control-heroin users  (see Cocainics (80 and 75%), ethanol of > 50 mg% (29 and 35%), other drugs of abuse (15 and 19%) and anti-epileptics (3 and 3%) were present at similar percentages in the heroin users positive for PGL (est) see .n = 3750). Our data show that heroin users who take PGL have a higher prevalence of prescription only CNS-depressant drugs present compared to those who take heroin without PGL. We also found that the prevalence of other CNS depressants is higher in non-heroin users who take PGL compared to heroin users positive for PGL. To the best of our knowledge, this is the first study to provide evidence that shows heroin users have statistically higher concentrations of PGL than non-heroin users (P = 0.002), albeit the difference observed may not be clinically significant.This is the first UK-based study that has screened for and quantified PGL in the femoral-vein bloods of an entire PM cohort (n = 229), a range comparable to those seen in PM bloods by other forensic laboratories, <0.1–226 µg/mL   , 22, 31.s, etc.) , it undes, etc.) ; therefon = 69) and non-heroin users (n = 160), it was found that poly-pharmacy was common in both groups. The classic combination of drugs used by heroin users were as expected with cocainics, benzodiazepines and methadone being more prevalent in the heroin users compared to the non-heroin users. Interestingly, the results also showed that a high proportion of those who used PGL, in both heroin users and non-heroin users, were also positive for anti-depressants (56.5 and 66.9%) and non-heroin-related opioids (33.3 and 55.6%); both have CNS-depressive effects and will enhance the depressive effects with PGL. It needs to be highlighted that the prevalence of anti-depressants and non-heroin-related opioids was greater in the non-heroin users than the heroin users. These results show that those who take PGL are vulnerable individuals regardless of whether heroin is taken or not; they have the potential to take a mixed drug overdose either intentionally  or accidently due to the combination of drugs that are available to them to take. Due to the findings of this study, the authors’ recommend that prescribers should be cautious when prescribing multiple CNS depressants to individuals. This is especially important when prescribing to those with a history drug misuse or mental health issues.On subcategorizing the PGL positive cohorts into heroin users (n = 67) to that in non-heroin users (n = 149), with the outliers removed, highly “significant” statistical differences were observed (P = 0.002). The 50th (median) and 75th percentiles of the PGL concentration distribution were 8 and 16 µg/mL in the heroin users and 5 and 11 µg/mL in the non-heroin users, respectively. Two clinical studies established that individuals given PGL at 600 mg per day (maximum recommended daily dose) had serum concentrations ranging from 0.87 to 14.2 µg/mL . This suggests that there is no relationship between the amounts of heroin and PGL taken by an individual. No statistical difference was observed between the morphine concentrations (from heroin use) in the PGL-positive heroin users (n = 69) and the control-heroin users (n = 264). This indicates that the amount of heroin used is not dependant on whether or not PGL is taken (P = 0.98). It may be true that heroin users who state they are taking PGL to help with their withdrawal symptoms, are doing so, but are possibly taking PGL without reducing their intake of heroin. However, the lack of correlation seen may be due to the staggering of drug taking rather than taking PGL and heroin together and also because of the difference in the half-lives of both drugs  (No correlation was observed between the concentrations of morphine from heroin use and PGL in the heroin users (ctively) . TherefoWhen the concomitant use of other drugs was compared between the heroin users positive for PGL and the control-heroin users, unexpectedly, it was discovered that heroin users positive for PGL had significantly higher prevalence for anti-depressants (57 and 19%), benzodiazepines (51 and 16%), methadone (45 and 25%), non-heroin-related opioids (33 and 8%) and anti-psychotics (22 and 6%) compared to the control-heroin users. This high prevalence of benzodiazepines and methadone among those who also use PGL was also seen in a recent study from Israel that demonstrated that 31% of all patients on a methadone treatment program were misusing PGL, and all those who were misusing PGL were positive for benzodiazepines . The higIf the latter is the case then these individuals require close monitoring by the prescribers.Although a routine drugs screen was conducted on the entire PM cohort, not all cases underwent a specific morphine screen or urine drugs of abuse screen. This was due to a morphine screen not being requested by the pathologist or limitations of the specimens submitted for analysis. However, in all cases where the case documents mentioned any form of drug use or drug paraphernalia related to heroin use , a morphine screen was conducted on femoral-vein blood to ensure heroin use was not being missed. Due to the nature of PM analysis, only heroin users with relatively recent use of heroin prior to death could be included in the heroin-user category as the inclusion criteria required the presence of morphine in a biological specimen. This means that some individuals in the non-heroin-user category may be heroin users who had not used heroin recently. Unfortunately, full prescription histories and dosages are generally not provided with the coronial cases, which makes it difficult to determine if the PGL taken had been misused illicitly by the deceased or was a prescribed medication; such information would facilitate our understanding of drug taking patterns.Our finding suggests that prescribers should to be cautions when co-prescribing CNS depressants with PGL to all patient groups not just to heroin users. It is recommended that all drug treatment centers should screen for illicit use of PGL on those who use heroin and those on the methadone maintenance program to help prevent PGL-associated heroin/opioid deaths.


Anti-interferon-gamma autoantibody-associated immunodeficiency syndrome is a rare and underrecognized adult onset immunodeficiency syndrome associated with severe opportunistic infections such as disseminated nontuberculous mycobacterium. Few cases have documented a relationship with IgG4-related disease. Concomitant diagnoses of these diseases present a diagnostic and management challenge.A 61 year old man of Southeast Asian descent with pulmonary mycobacterium avium complex infection presented to our hospital system with a new skin rash and worsening lymphadenopathy. He was eventually diagnosed with IgG4-related disease through excisional nodal biopsy. He was managed with immunosuppressive treatment with prednisone, rituximab and cyclophosphamide. He later re-presented with disseminated mycobacterium avium complex infiltration of his joints, bones and prostate. Original titers of anti-interferon-gamma autoantibodies were falsely negative due to being on immunosuppressive therapy for his IgG4-related disease. However, anti-interferon-gamma autoantibody titers were re-sent after immunosuppression was held and returned strongly positive.This case reviews diagnostic criteria and discusses management strategies with existing challenges in treating a patient with concomitant adult onset immunodeficiency syndrome, IgG4-related disease and a disseminated mycobacterial avium complex infection. Anti-interferon-gamma autoantibody-associated immunodeficiency syndrome is an emerging adult onset immunodeficiency (AOID) disease. Acquired, neutralizing autoantibodies inhibit the downstream signaling of interferon (IFN)-gamma causing an increased susceptibility to intracellular pathogens leading to severe disseminated infections, especially nontuberculous mycobacterial (NTM) species . First dImmunoglobulin G4-related disease (IgG4-RD) can be misdiagnosed given its clinical presentation can mimic other disease processes including infections, cancer, or other immune mediated conditions. As a result, the true prevalence of IgG4-RD is unknown. The reported incidence rate of IgG4-RD was estimated to be around 1 case for every 10,000 residents in Japan .Due to the novelty of both IgG4-RD and AOID, the natural history of these diseases is often described through case report and remain poorly understood. Thus, management continues to be a challenge.The diagnostic criteria of IgG4-RD and diagnosis of AOIDThe pathophysiologic mechanisms of overlap between the two diseasesThe literature on management of IgG4-RD and AOIDTreatment strategies in a patient with concomitant AOID, IgG4-RD and disseminated MAC infection.Furthermore, a concomitant diagnosis of AOID and IgG4-RD has only been described twice in the literature , 7. TreaA 61-year-old man of Taiwanese descent was referred to our hospital for evaluation of a new skin rash. One year prior to our evaluation, the patient presented to an outside community hospital with several weeks of constitutional symptoms including fevers, chills and weight loss and was found to have diffuse lymphadenopathy involving his mediastinal, hilum, and axillary lymph nodes. He underwent bronchoscopy with bronchoalveolar lavage which was positive for pulmonary MAC. He was started on treatment with clarithromycin, ethambutol, and rifampin.Three months into treatment, the patient self-discontinued his ethambutol as he developed a new skin rash that he attributed as a side effect to this antibiotic. The patient was referred to our dermatology clinic at Keck Medicine of University of Southern California (USC) for evaluation. The physical exam was pertinent for a painful diffuse maculopapular rash involving the face and trunk Fig. . Punch bThe patient was also seen in our ophthalmology clinic for bilateral anterior uveitis, which was thought to be secondary to an inflammatory response to his MAC infection vs RDD. The patient was seen in the pulmonary clinic and repeat sputum cultures were negative for MAC and computed tomography (CT) imaging showed stable lymphadenopathy. Due to the reported skin rash side effect, the patient continued dual therapy with clarithromycin and rifampin and was monitored with monthly sputum samples.Unfortunately, the patient was lost to follow up due to the COVID-19 pandemic. Seven months into treatment of his MAC infection, the patient re-presented to another outside community hospital with worsening constitutional symptoms and weakness to the point at which he was not able to get out of bed. He had a rising leukocytosis to 50 k/mcL with lymphocytic predominance (from a baseline of 10 k/mcL) and progression of his lymphadenopathy for which a core biopsy of his axillary lymph node was performed. Biopsy did not reveal histopathological findings of RDD—it revealed lymphocytic infiltration with IgG4+plasma cells up to 70 per high power field, but with an IgG4+/IgG ratio of < 30%. This did not meet criteria for a diagnosis of IgG4-RD. Acid fast bacilli (AFB) stain was negative. Flow cytometry and molecular NeoGenomics tests came back negative. The patient was referred to our hematologist who recommended an excisional lymph node biopsy, a bone marrow biopsy, and a positive emission tomography (PET) scan.The PET scan revealed diffuse hypermetabolic lymphadenopathy involving his supraclavicular, mediastinum, hilar, and axillary lymph nodes. Thus, a repeat excisional biopsy of the right axillary lymph node was performed showing a markedly expanded population of mixed inflammatory cells replacing most of the lymph node architecture, including neutrophils, small lymphocytes, plasma cells, and scattered immunoblasts Fig. A. CapsulA shared decision was made to initiate immunosuppressive therapy for IgG4-RD with dexamethasone 40 mg for 4 days and a rituximab 1000 mg infusion, given the patient had 7 months of negative sputum samples with an initial biopsy interpretation negative for AFB. While his IgG4 levels rapidly responded to treatment, outpatient monitoring of his inflammatory markers were slow to improve despite 3 cycles of the aforementioned immunosuppressive therapy. Eventually 1500 mg of cyclophosphamide was added for the 4th cycle  is also associated with AOID , 7, 14. In a Thailand and Taiwan cohort, IFN-gamma auto-antibodies were detectable in over 80% of patients suffering from disseminated NTM without previously known risk factors such as human immunodeficiency virus (HIV) . DiagnosThe relationship between IgG4-RD and AOID is an area that requires further research and has only been described twice before to our knowledge , 7. The To date, the pathogenesis of IgG4-RD is also incompletely understood. Some have suggested that IgG4-RD is precipitated by a likely unknown antigen that causes B cell differentiation into IgG4 producing plasma cells leading to the increased expression of T helper 2 (Th2) cells and cytokines , 18. TheAs disseminated mycobacterial disease has been shown to increase a Th2 immune mediated response, it has been suggested that prolonged opportunistic infections due to underlying AOID results in activation of Th2 cells and repeated antigen exposure causes increased IgG4 production , 21. AnoManagement strategies of both diseases involve steroids and biologic agents. International consensus guidelines recommend that all symptomatic patients with IgG4-RD and most asymptomatic patients with the potential for irreversible organ damage receive induction therapy due to the metachronus nature of the disease . Inducti2 weekly) for 9–15 cycles over 1–5 years in 4 patients with periods of relapsed disease but overall clinical, radiologic, and laboratory improvement [Treatment for AOID is an area of ongoing research with no published guidelines to guide management choices. Multiple treatments have been trialed in case reports with varying success including intravenous immunoglobulin, subcutaneous IFN-gamma, plasmapheresis, cyclophosphamide and rituximab , 22–26. The management of pulmonary MAC in general remains challenging, especially in an immunocompromised host. The advent of macrolide-based regimen was a turning point in MAC treatment, leading to its foundational recommendation in guidelines since 1997 –29. The 3 regardless of ART [While immunosuppression is an established risk factor for mycobacterial disease, robust evidence-based guidelines are lacking for most immunocompromised hosts, including patients with transplants  and thoss of ART . This chThe largest longitudinal study on AOID treatment found that infection clearance was dependent on the use of immunosuppressives . The medThis case highlights the diagnostic challenge of concomitant AOID, IgG4-RD and disseminated MAC infection, the severity of morbidity and reviews optimal treatment strategies. Because of the novelty and rarity of these diseases, further research is needed to help classify the spectrum of disease between AOID, IgG4-RD and disseminated MAC infection in order to refine treatment strategies in this growing, high-risk population.


To investigate the influence of addition amount and length of steel fibers on the bearing capacity of a concrete beam, this study simulated the crack propagation process of a concrete beam in a four-point bending experiment. The extended finite element method (XFEM) using the ABAQUS software was adopted. Additionally, stress distribution trends for the concrete under loading and load–displacement curves at the stressed points were obtained. The simulation results for a concrete beam with different amounts and lengths of steel fibers were compared and analyzed, and conclusions were drawn. The experiment shows that the flexural performance of the concrete improves with increases in the length and amount of steel fibers, but the reinforcement effects produced by different amounts and lengths of steel fibers are different. When the steel fiber content is 1.5% and the length is 20–25 mm, the reinforcement effect in the concrete is significantly improved, and its flexural strength is nearly doubled. Concrete material has many advantages, such as easy preparation, low price, high compressive strength, good durability, and so on, so it has been generally used in the construction industry. In recent years, higher requirements for building materials have been proposed, and the disadvantages of plain concrete, such as low tensile strength, easy cracking, and low toughness, have also received significant attention and research . In partFurthermore, a refined diffuse cohesive approach for the failure analysis of quasibrittle materials, such as concrete, has recently been proposed ,10. SteeBelytsckho and Black  proposedScientists have carried out several experimental studies on the mechanical properties of fiber-reinforced concretes. Li et al.  studied Although progress has been made in the reinforced theory of steel-fiber-reinforced concrete, it is significant to evaluate the influence of steel fiber amount and length on concrete performance and clarify the influence degree of the steel fiber content on the flexural strength of the concrete. In this study, simulated groups were established for concrete with different length and amount of steel fibers, and displacement–load curves were obtained from numerical simulations.The extended finite element method  is a numu, which uses the overall division characteristic, can be expressed by Equation (1):N1(x) is a commonly used node displacement function; u1 in Equation (1) represents the corresponding continuous part in the finite element displacement solution, used for all nodes in the model; a1 is the node extended degree of freedom vector, which is only valid for the element node whose shape function is cut by the crack interior; and H(x) represents the discontinuous jump function along the crack surface; and aF(x) is the asymptotic function of stress at the crack tip. H(x) can be expressed by Equation (2):x is the sample point; x* is the nearest point in the crack spacing to x; n is the unit out normal vector of x* in the crack. The expansion functions include near-tip asymptotic functions to simulate the stress singularity near the crack tip, as well as discontinuous functions to represent the displacement jump at the crack surface. The displacement vector function, r and θ represent distance and angle in the polar coordinate system that take the crack tip point and crack extension direction as the pole and pole axis.In Equation (3), Based on the finite element software ABAQUS, a four-point bending numerical model for steel-fiber-reinforced concrete was established using the XFEM module. In the simulation process, it was presumed that steel fibers are embedded in concrete, and cracking is random without prefabricated crack, regardless of boundary slip. First, randomly distributed steel fibers were generated through scripts, whose length is 10 to 15 mm. Then, a concrete model with dimensions of 120 cm × 10 cm × 10 cm was established. Concret-xfem material is used for concrete, and the maximum principal stress and fracture energy are 67.1 MPa and 4200 N/m, based on the damage evolution of energy. The steel fiber adopted Beam–Truss section property with yield strength of 235 MPa. The material parameters of the concrete and steel fibers are shown in The steel fibers were dispersed in the concrete evenly. The static analysis is used with the nonlinearity. In addition, the field output was set including SDEG , PHILSM , STATUS, and STATUSXFEM. The historical output set the displacement and reaction force in the Z direction of the output reference point in order to obtain the load displacement curve. Tie constraints were set for all contact surfaces between rigid blocks and concrete specimens. The crack-XFEM type failure mode was set for concrete, and the XFEM-crack-growth allowing crack growth was set. The Embed Region constraint was adopted between reinforcement and concrete. We set all reinforcement to the Embed Region, and concrete specimens to the host region. Taking the concrete as the crack propagation area, the propagation characteristics were defined by a crack propagation analysis, and crack growth was allowed. For grid type, the concrete was set as a C3D8R unit with number of 12,000, and the steel fiber was set as a T3D2 unit with number of 2064. Through multiple pretreatment analyses, the sizes of the concrete grid divisions were determined and divided into 2556 units, as shown in The constraint on the lower left end of the beam was set as a fixed hinge support, and it constrains displacement in the x-, y-, and z-directions and rotation in the x- and y-directions. The lower right end constraint was set as a rolling hinge support, and it constrains displacement in the y- and z-directions and rotation in the x- and y-directions .To prevent local compressive break of the concrete beam, rigid body gaskets with dimensions of 10 cm × 5 mm × 2.5 mm were placed at the supports and stress points. Displacement loads were applied at two loading points, and the loads produced a vertical downward displacement of 3 mm.The maximum principal stress criterion was adopted as the concrete cracking criterion. When the maximum stress reaches a certain value, damage occurs.The signed distance function (PHILSM) in ABAQUS is the level set function used to describe the development of the crack surface, in which the PHILSM value transitions from negative to positive unit is the location of the crack surface. The upper end of the concrete beam is subjected to compressive stresses and the lower end is subjected to tensile stresses. As shown in Corresponding to Corresponding to In The breaking load for each group of the concrete was recorded, and the results were shown in When 2–3 mm steel fibers are added, the flexural strength of the concrete does not show significant improvement. The flexural strengths for groups B-1, B-2, B-3, and B-4 are 5.60 MPa, 5.63 MPa, 6.11 MPa, and 6.13 MPa, respectively, which are only 0.1%, 0.5%, 9.1%, and 9.8% higher than that of group A-1, respectively. Due to the short length of the steel fibers, the bonding force between the steel fiber and the matrix interface is insufficient, and the fibers are easily pulled out from the concrete during the cracking process. The tensile properties of the steel fibers cannot not fully exert, and crack propagation develops quickly. When steel fibers with 15–20 mm length are added, the increases in flexural strength for concrete are obvious. The flexural strength values for groups E-1, E-2, E-3, and E-4 are 5.78 MPa, 5.83 MPa, 6.87 MPa, and 7.59 MPa, respectively, which are 3.2%, 3.6%, 12.4%, and 23.4% higher than that of the A groups.When the steel fiber lengths increase from 15–20 mm to 20–25 mm, the flexural strength of concrete does not show obvious improvement. The fiber length of the F-4 group increases by 20% with respect to that of the E-4 group, but the flexural strength increases from 14.21 MPa to 14.44 MPa, with improvement accounting for only 1.6%. This shows that the length enhancement effect of steel fibers for SFRC is insignificant from group E to group F. Increasing the length of the steel fibers cannot improve the flexural strength of the concrete. Because the tensile strength of the steel fibers is already less than the bonding force between steel fibers and matrix, the fracture resistance of the concrete cannot significantly improve.Adding an amount of steel fibers into concrete can reduce the number of cracks in the concrete matrix during the hardening and consolidation stage of the concrete. Moreover, a random distribution of steel fibers in the matrix can delay the formation and expansion of concrete micro-cracks, thereby improving the flexural strength of the concrete beam .When 300 short steel fibers are added, the flexural strength improvement of concrete is very small for the experimental group. The flexural strengths for groups B-2, C-2, and D-2 are 5.63 MPa, 5.83 MPa, and 6.04 MPa, respectively, whose increases are 0.5%, 0.9%, and 2.9% related to group A-1. For long steel fibers, the improvement is very obvious. The flexural strengths for groups E-2 and F-2 are 8.65 MPa and 10.83 MPa, respectively, increasing 43.2% and 76.4% to group A-1.When 500 steel fibers are added into concrete, the flexural strengths for groups B-3, C-3, D-3, E-3, and F-3 are 6.11 MPa, 6.87 MPa, 9.07 MPa, 11.47 MPa, and 13.75 MPa, respectively, increasing 8.5%, 17.8%, 50.1%, 32.6%, and 27.0% compared with group A-1. After the steel fiber length increases to a certain extent, increasing the amount of steel fibers can significantly increase the number of steel fibers per unit area of the concrete, making the tensile properties of the steel fiber greatly impact the concrete properties.When 700 steel fibers are added, the flexural strengths for groups B-4, C-4, D-4, E-4, and F-4 are 6.15 MPa, 7.59 MPa, 10.19 MPa, 14.21 MPa, and 14.44 MPa, showing increases of 0.7%, 10.4%, 12.3%, 23.9%, and 5.0% compared with group A-1. Additionally, slopes of the bending strength curves become shallower again. With the increase in the steel fiber number, although the flexural strength of the concrete still increases, the growing rate of the flexural strength decreases. In fact, if the steel fiber amount continues to increase, agglomeration will also appear in the concrete.The amount and length of the steel fibers have different effects on the fracture resistance of the concrete beams. The addition of steel fiber to concrete is not only based on the mechanical strength of the SFRC, but also on the economic benefits. Therefore, a relative improvement degree evaluation index is introduced, which is analyzed depending on the length and quantity of the steel fibers. Regarding the relative improvement in the SFRC, 300 steel fibers with lengths of 20–25 mm were proposed to be an optimal addition amount and length, whose Relative Lifting Degree is 3.49 .FG) is the energy required for the complete failure of concrete specimen, and it is an important index to characterize the fracture properties of materials. Its formula is expressed as:Fracture energy When the steel fiber addition amount increases from 0 to 3.5%, the flexural strength of the SFRC increases from 5.60 Ma to 14.44 Ma.(2)When the length of the steel fibers increases from 2–3 mm to 20–25 mm, the flexural strength of the concrete increases accordingly.(3)Considering the economic benefits and mechanical properties comprehensively, the steel fiber amount of 1.50% in the concrete with length of 20–25 mm is proposed to be an optimal selection.(4)When the steel fiber volume content increases from 1.13% to 1.50%, the increase in fracture energy and fracture resistance for concrete is insignificant.


In this study, the effect of waste glass on the mechanical properties of concrete was examined by conducting a series of compressive strength, splitting tensile strength and flexural strength tests. According to this aim, waste glass powder (WGP) was first used as a partial replacement for cement and six different ratios of WGP were utilized in concrete production: 0%, 10%, 20%, 30%, 40%, and 50%. To examine the combined effect of different ratios of WGP on concrete performance, mixed samples  were then prepared by replacing cement, and fine and coarse aggregates with both WGP and crashed glass particles. Workability and slump values of concrete produced with different amounts of waste glass were determined on the fresh state of concrete, and these properties were compared with those of plain concrete. For the hardened concrete, 150 mm × 150 mm × 150 mm cubic specimens and cylindrical specimens with a diameter of 100 mm and a height of 200 mm were tested to identify the compressive strength and splitting tensile strength of the concrete produced with waste glass. Next, a three-point bending test was carried out on samples with dimensions of 100 × 100 × 400 mm, and a span length of 300 mm to obtain the flexure behavior of different mixtures. According to the results obtained, a 20% substitution of WGP as cement can be considered the optimum dose. On the other hand, for concrete produced with combined WGP and crashed glass particles, mechanical properties increased up to a certain limit and then decreased owing to poor workability. Thus, 10% can be considered the optimum replacement level, as combined waste glass shows considerably higher strength and better workability properties. Furthermore, scanning electron microscope (SEM) analysis was performed to investigate the microstructure of the composition. Good adhesion was observed between the waste glass and cementitious concrete. Lastly, practical empirical equations have been developed to determine the compressive strength, splitting tensile strength, and flexure strength of concrete with different amounts of waste glass. Instead of conducting an experiment, these strength values of the concrete produced with glass powder can be easily estimated at the design stage with the help of proposed expressions. Durinmosphere . Therefomosphere ,5. Wastemosphere ,12,13,14mosphere . Waste gmosphere ,19,20,21mosphere ,23.According to ASTM C618-19, 2019, since waste glass consists of a large amount of calcium and an amorphous structure, it can be ground into powder to obtain pozzolanic material or cement additive ,25,26. TDust and particles from soda glass were mostly used in previous studies. However, its usability in concrete was investigated by replacing fine aggregate in self-compacting concrete with waste particles obtained from cathode ray tubes. The results had a positive effect on the durability properties of concrete . Past stSolid waste management is an important issue for most developing countries . InsteadIn this study, the main aim is to investigate the effect of glass powder when it is replaced with cement. Furthermore, the effects of all replacements with glass are investigated. Nine mixes including the reference were designed. C represents cement replacement, MIX represents cement, fine aggregate, and coarse aggregate replacement. Cement was selected as CEM I 32.5 Portland cement. The water-to-cement ratio was chosen as 0.5. Three types of tests were performed in order to evaluate the performance of the concrete with recycled glass. A compression test was performed on 15 × 15 × 15 cm cubic samples while splitting tests were conducted on 10 × 20 cm cylinder samples. Furthermore, bending tests were performed using 10 × 10 × 40 cm samples. Three repetitions were completed for each mix and each test. Compressive ability is the capability of a specimen to decline load under pressure. The CST was performed according to ASTM C39/C39M . In this test, specimens have dimensions of 150 mm × 300 mm. In this experiment, concrete specimens were subjected to constraint lengthwise load at a level in the offered as concerns the specimen fractures. At that point, the compressive capability was estimated from the critical failure strength separated by the part of the specimen. To provide the tensile strength of concrete where compactor load is performed in anticipation of examples unravel caused by expansion of tensile force in concrete as ASTM . In this way, cylindrical examples are divided through the vertical dimension.In this part, to carry through the compressive strength test (CST), concrete examples were arranged without any adulteration. In the comparison of the cement that was changed with waste glass powder, the CS of C10% (10% cement replaced with waste glass) is 6% greater than that of C20%. Correspondingly, the CS of C20% (20% cement replaced with waste glass) is 60% greater than that of C30%. Comparing the CS of C30% (30% of the cement was replaced with waste glass powder) it can be observed that the value is 15% greater than that of C40%. Finally, the comparison of CS of C40% (40% of the cement was substituted with waste glass powder) is 31% greater than that of C50%. Consequently, it is observed that the CS of C10% (10% cement was replaced with waste glass powder) is similar to that of reference concrete. As shown in A comparison of relative STS of the various concrete percentage combinations formed with 100% reference and numerous ratios of recycled aggregate replacing reference aggregates, with and without waste glass are shown in Flexure strength (FS) of investigational examples was established on examples after CST. The acquired norms of strength ranged between 6.6 MPa and 3.9 MPa. The consequence of the FS of the examples is presented in The effect of waste glass on the structural performance of concrete was investigated by many research teams. Effects of the use of waste glass as cement replacement on some mechanical properties such as CS, STS, and FS have been investigated. In this part of the study, values of CS, STS, and FS for plain concrete and concrete produced from different glass powder amounts have been collected from the research publications ,61,62,63f is strength values as follows: cf: compressive strength tf: splitting tensile strength; ff: flexure strength; WGPR: waste glass power ratio (0 < WGPR < 50). 1c and 2c are coefficients given in f′ is strength values of the plain concrete.As shown in these figures, with the addition of waste glass, the strength values of concrete produced with glass powder generally decrease after a certain value. The maximum decrease in compressive strength was observed in the study by Kalakada et. al., 2022. When the cement was partially replaced with glass powder at 50%, there is a 65% reduction in compression strength of the plain concrete specimen. In the same manner, a 20% addition of the waste glass leads to a 36% reduction in the splitting tensile strength of the plain concrete specimen in the study of Abdulazeez et al., (2020). With the addition of 50% glass powder, a 38% reduction in flexural strength was observed in our experimental study. Thus, a rational design expression was developed to consider these reductions in the strength values as follows:WGPR). These expressions can be easily used in the design stages.As shown in Equation (1), CS, STS, and FS values of concrete produced with waste glass were expressed as a function of the amount of the waste glass (Scanning electron microscope (SEM) analysis was performed from the sample pieces taken after the compressive strength test from the concrete samples produced with recycled glass waste powder. SEM analysis is carried out to show the typical morphology of the surface tissue of OPC and WGP. The particles of both OPC and WGP are composed of glassy structures and irregular shapes with sharp edges. OPC particles consist of sharper edges and shapes, while WGP particle appears on smoother surfaces, sharper prismatic edges, and denser content . The besBased on the slump test, the slump value decreases as the amount of waste glass increases. In the same manner, the workability decreases when the rate of glass powder increases.The compressive test results indicated that the usage of WGP as a replacement of cement adversely affects the compressive strength of concrete. Compared to the reference sample, 10%, 20%, 30%, 40% and 50% replacement of WPG reduced the compressive strength by 3%, 6%, 37%, 13% and 23%, respectively.On the other hand, when cement, fine and coarse aggregates were replaced with waste glasses, there was an increase in the compression strength, the flexural and splitting tensile strength values up to a certain value of the amount of the waste. However, further increasing the waste glass addition led to a decrease in the compression value.According to the results of the split tensile and bending strength tests, the strength values decrease as the value of the substitution of cement with waste glass increases. Compared to plain concrete, 50% replacement of WPG reduced the splitting tensile strength by 34%, respectively. On the other hand, this replacement reduced flexural strength by 38%.When cement, fine and coarse aggregates were replaced with waste glasses there was an increase in the flexural and splitting tensile strength values up to a certain value of the amount of the waste glass. However, further increasing the waste glass addition resulted in a decrease in the strength values. Replacing the waste glass by 10% resulted in a 5% increase in splitting tensile strength while replacing the waste glass by 30% resulted in a 14% decrease in splitting tensile strength. On the other hand, a 10% substitute of waste glass resulted in a 5% increase in flexural strength, while a 30% substitute of waste glass resulted in an 11% decrease in flexural strength.It can be concluded that when waste glass is used instead of cement, fine and coarse aggregate, significant increases in strength are observed.SEM analysis results showed that there was a good bond between the glass powder and cementitious concrete.The proposed equations for the compressive strength, flexural, and splitting tensile strength are quite general and they can be suitable for direct adoption into design specifications of the concretes produced with waste glass.Waste management has gained great importance due to the increase in the amount of waste. The reuse or recycling approach of these waste products, especially in the construction sector, has become a more attractive option. In this study, the applicability of waste glass on concrete production was investigated by considering two different conditions, i.e., replacing cement with waste glass powder and replacing cement, fine and coarse aggregate with waste glasses. A series of tests were conducted on concrete samples produced with different amounts of waste glass to determine engineering properties both in the fresh and hardened cases. In the fresh case of concrete, workability and slump properties were explored. In the case of hardened concrete, compression strength, splitting tensile strength, and flexural strength of the produced test specimens were investigated. These properties were then compared with those of plain concrete. Then, SEM analysis was carried out to explore the interaction between glass powder, cement, and aggregates. Furthermore, practical equations were developed to identify the compressive strength, splitting tensile strength, and flexure strength of concrete produced with WGP. Based on our study, the following conclusions can be drawn:In this study, it was observed that waste glass can be used as a partial cement substitute, or as cement, fine and coarse aggregate in concrete. Optimum waste glass dosage has also been identified for design purposes. However, lower strength values were observed when waste glass was used as a partial replacement for cement. The current study defines waste glass as suitable, reachable in large amounts, a local eco-material, cheap, that can be selected for concrete construction, in a point of view between economically and environmentally responsive. To mitigate this shortcoming, future studies will concentrate on the use of waste glass with other recycling fibers.