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The safe disposal of an enormous amount of waste glass (WG) in several countries has become a severe environmental issue. In contrast, concrete production consumes a large amount of natural resources and contributes to environmental greenhouse gas emissions. It is widely known that many kinds of waste may be utilized rather than raw materials in the field of construction materials. However, for the wide use of waste in building construction, it is necessary to ensure that the characteristics of the resulting building materials are appropriate. Recycled glass waste is one of the most attractive waste materials that can be used to create sustainable concrete compounds. Therefore, researchers focus on the production of concrete and cement mortar by utilizing waste glass as an aggregate or as a pozzolanic material. In this article, the literature discussing the use of recycled glass waste in concrete as a partial or complete replacement for aggregates has been reviewed by focusing on the effect of recycled glass waste on the fresh and mechanical properties of concrete.

Geopolymer (GP) concrete is a novel construction material that can be used in place of traditional Portland cement (PC) concrete to reduce greenhouse gas emissions and effectively manage industrial waste. Fly ash (FA) has long been utilized as a key constituent in GPs, and GP technology provides an environmentally benign alternative to FA utilization. As a result, a thorough examination of GP concrete manufactured using FA as a precursor (FA-GP concrete) and employed as a replacement for conventional concrete has become crucial. According to the findings of current investigations, FA-GP concrete has equal or superior mechanical and physical characteristics compared to PC concrete. This article reviews the clean production, mix design, compressive strength (CS), and microstructure (Ms) analyses of the FA-GP concrete to collect and publish the most recent information and data on FA-GP concrete. In addition, this paper shall attempt to develop a comprehensive database based on the previous research study that expounds on the impact of substantial aspects such as physio-chemical characteristics of precursors, mixes, curing, additives, and chemical activation on the CS of FA-GP concrete. The purpose of this work is to give viewers a greater knowledge of the consequences and uses of using FA as a precursor to making effective GP concrete.

Foamed concrete is known for its weak strength due to the high porosity caused by air bubbles. The focus of this research was on studying the most important structural feature, which is the compressive strength at 7 &28 days of reinforced foamed concrete with different types of single fibres, such as hooked-ends steel fibres, corrugated steel fibres and polypropylene fibres. in addition to, foamed concrete reinforced with hybrid fibres (using the combination of polypropylene with hooked-ends Steel Fibres) and (combination of polypropylene with corrugated fibres), The best results were obtained basically using hybrid fibres of 0.4% hooked-ends steel fibres with0.3Kg/m3 polypropylene fibre followed by using 0.4% corrugated steel fibres with 0.3Kg/m3 polypropylene fibre.

Lightweight foamed concrete has recently been adopted as a more sustainable construction material due to various features such as reduction in member size, better thermal insulation, and cost savings. This work examines an attempt to improve the brittle nature of foam concrete with the addition of different types of fibres. Five types of fibres were used: steel fibres (hooked-ends), micro steel fibres (straight ends), carbon, glass, and polypropylene fibres. The effect of fibre type on the fresh (density and flowability) and hardened (compressive strength, splitting tensile strength, flexural strength, and static modulus of elasticity) properties of lightweight foamed concrete were thus investigated. The results collected from the experimental work revealed that steel fibres significantly improve the performance of lightweight foamed concrete in terms most properties while other types of fibres (carbon, glass and polypropylene fibres) improved properties at different levels to the steel fibres. Using 0.45 hooked-ends steel fibres gave the most significant improvement in splitting, flexural strength, modulus of elasticity and compressive strength at 162.5%, 83.78%, 72.41%, and 63.63%, respectively.

Colistin is an effective antibiotic for treatment of most multidrug-resistant Gram-negative bacteria. It is used currently as a last-line drug for infections due to severe Gram-negative bacteria followed by an increase in resistance among Gram-negative bacteria. Colistin resistance is considered a serious problem, due to a lack of alternative antibiotics. Some bacteria, including , , Enterobacteriaceae members, such as spp., and spp. have an acquired resistance against colistin. However, other bacteria, including spp., spp. and spp. are naturally resistant to this antibiotic. In addition, clinicians should be alert to the possibility of colistin resistance among multidrug-resistant bacteria and development through mutation or adaptation mechanisms. Rapidly emerging bacterial resistance has made it harder for us to rely completely on the discovery of new antibiotics; therefore, we need to have logical approaches to use old antibiotics, such as colistin. This review presents current knowledge about the different mechanisms of colistin resistance.

Background The purpose of this study was to look into the presence of plasmid-mediated quinolone resistance (PMQR) genes and biofilm formation in several species of clinical Shigella isolates that were resistant to quinolones. Methods The stool samples of 150 patients (younger than 10 years) with diarrhea were collected in this cross-sectional study (November 2020 to December 2021). After cultivation of samples on Hektoen Enteric agar and xylose lysine deoxycholate agar, standard microbiology tests, VITEK 2 system, and polymerase chain reaction (PCR) were utilized to identify Shigella isolates. The broth microdilution method was used to determine antibiotic susceptibility. PMQR genes including qnrA , qnrB , qnrC , qnrD , qnrE , qnrS , qnrVC , qepA , oqxAB , aac(6′)-Ib-cr , and crpP and biofilm formation were investigated in quinolone-resistant isolates by PCR and microtiter plate method, respectively. An enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) technique was used to determine the clonal relatedness of quinolone-resistant isolates. Results A total of 95 Shigella isolates including S. sonnei (53, 55.8%), S. flexneri (39, 41.1%), and S. boydii (3, 3.2%) were identified. The highest resistance rates of the isolates were against ampicillin (92.6%, n = 88/95). Overall, 42 of 95 (44.2%) isolates were simultaneously resistant against two or more quinolones including 26 (61.9%) S. sonnei and 16 (38.1%) S. flexneri . All isolates were multidrug-resistant (resistance to more than 3 antibiotics). The occurrence of PMQR genes was as follows: qnrS (52.4%), qnrA and aac(6′)-Ib-cr (33.3%), and qnrB (19.0%). The prevalence in species was as follows: 61.5% and 37.5% ( qnrS ), 19.2% and 56.3% ( qnrA ), 38.5% and 25.0 ( aac(6′)-Ib-cr ), and 19.2% and 18.8% ( qnrB ) for S. sonnei and S . flexneri , respectively. The other PMQR genes were not detected. In total, 52.8% (28/53) of quinolone-susceptible and 64.3% (27/42) of quinolone-resistant isolates were biofilm producers. Biofilm formation was not significantly different between quinolone-resistant and quinolone-susceptible isolates ( P -value = 0.299). Quinolone-resistant isolates showed a high genetic diversity according to the ERIC-PCR. Conclusion It seems that qnrS , qnrA , and aac(6′)-Ib-cr play a significant role in the quinolone resistance among Shigella isolates in our region. Also the quinolone-resistant S . flexneri and S. sonnei isolates had a high genetic diversity. Hence, antibiotic therapy needs to be routinely revised based on the surveillance findings.