Mass concrete has been commonly known for its thermal stresses which arise due to the entrapment of hydration temperature susceptible to thermal cracking. The utilization of mineral additives is a promising and widely adopted technique to mitigate such effects. This paper presents the thermal, physico-chemical, mechanical, and morphological behaviour of mass concrete with blends of bentonite (BT) and fly ash (FA). Apart from the rise in temperature due to hydration, the compressive strength, ultrasonic pulse velocity (UPV), differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) analysis, and microstructure were studied. The results of this study revealed that the substitution of BT and FA significantly improved the compressive strength and development rate of UPV in the mass concrete samples. The FA concrete (FC) specimen presented the lowest temperature during the peak hours compared to all other concrete mixes studied in this research. Bentonite concrete (BC) was also found to be more effective in controlling the escalation of temperature in mass concrete. Scan electron microscopy (SEM) micrographs presented partially reacted FA particles in a mix. XRD and DTA analysis indicated that the concentration of calcium hydroxide (CH) declined by substituting FA and BT, specifically in ternary blends, which was due to the dilution effect and consumption of CH through the pozzolanic reaction. Thermal stresses in mass concrete often rise due to the hydration of cement. The temperature differences in mass concrete may vary during its placement ,2. The t2 during the manufacturing process of cement [Various methods are adopted to control the temperature in mass concrete based on their availability, handling, and cost effectiveness. The most common way to reduce the thermal effect in concrete is to utilize pozzolanic materials by substituting the bulk proportion of cement in mass concrete production. The decrease in the amount of heat of hydration and thermal stresses is related to the decrease in the amount of cement . The pozf cement . The estf cement . The totf cement . The repBentonite (BT) is an alumina-siliceous material that produces a high amount of aluminium and siliceous compounds during its pozzolanic reaction. Pakistan has large and abundant reservoirs of BT clay, which is used for several industrial applications. However, its applications in the construction sector are not well-documented among all the well-established pozzolanic materials, such as FA, SF, rice husk ash (RHA), and MK, etc. There are few studies which report the effects of BT on concrete mechanical and durability properties. Memon et al.  studied Several researchers have examined the effects of BT on the mechanical and durability properties of normal concrete. However, its effects on physico-chemical, thermal, and morphological properties of mass concrete have not been well-explored. Therefore, this study was designed to assess the effectiveness of BT as partial replacement to the cement on the aforementioned properties of mass concrete. Since the FA is the most commonly used pozzolan in concrete, mass concrete mixes containing FA separately and together with BT were also prepared to compare the performance of BT with FA and control mix.All materials were characterized for their chemical composition by the X-ray florescence  technique prior to their use in concrete. Type I ordinary Portland cement (OPC) confirming the requirements suggested by ASTM C150  was utilThe experiment program was carried out to investigate the physico-chemical, mechanical properties, and thermal effect on binary and ternary blended concrete mix prepared with FA, BT, and OPC. Four different types of concrete samples were prepared with different proportions of FA and BT as substitutions to OPC by mass in concrete mix, as presented in In total, 15 standard sized cylinders (15.24 cm × 30.48 cm) and four massive concrete blocks with dimensions (60 cm × 60 cm × 40 cm) were cast, i.e., control concrete (CC), 30% FA (FC), 30% BT (BC), and a combination of 15% FA and 15% BT (FBC), respectively. The fresh concrete was poured in layers and compacted using vibrators  to remove air voids. Four embedded thermocouple sensors  were placed in the central and outer parts of mass concrete blocks to record the temperature, as shown in The experiments were performed in two phases. In the first phase, an increase in the temperature was recorded after the casting of the concrete block. The temperature deviation was declined after reaching its peak values. The test was terminated when the declined temperature in the central zone attained a similar temperature value to the surface zone in the mass concrete block. In the second phase, besides the compressive strength test, the ultrasonic pulse velocity  was measured at 7, 14, 28, 56, and 91 days of curing. The compressive strength behaviour and UPV values were also recorded on mass concrete blocks. The blocks were divided into two parts, named surface (outer) and central (core), as shown in This property of concrete is considered a basic design parameter of concrete structures. All other properties of concrete can be judged on the basis of compressive strength. The rate of strength development was also determined with reference to the value of compressive strength obtained at seven days ,23 Figu. The valUltrasonic pulse velocity (UPV) is a non-destructive test used to quantify the strength of concrete. UPV results are affected by the density and internal cracks of a concrete specimen. The data for UPV values are presented in terms of km/s. This test was performed on cylinder specimens and mass concrete specimens. The values for UPV on cylinder specimens containing mineral additives at 7, 14, 28, 56, and 91 days are shown in At an early age, FC showed a lower value compared to CC, but a value higher than that of BM and FBC. It was then gradually increased with respect to time. In addition, BC also presented lower values than CC till 56 days, and the value was closer to CC at 91 days. The reduction in the values were due to the lower hydration. The hydration rate in normal concrete was high compared to the concrete containing pozzolanic materials. It is observed that BT has a good pozzolanic reactivity since the values continued to increase until 91 days. The significant increments in UPV value for CC were attributed to the denser microstructure. The FBC showed almost the same pattern as FC. However, slightly smaller values were recorded at initial ages, and thereafter, an elevated curve was observed at 56 days.−1 for all cylinder specimens at all curing ages, which indicated that the type of concrete was in the range of “good concrete”. The influence of BT and FA on the development rate of UPV of cylindrical concrete specimens is shown in Based on UPV values, the concrete’s quality was characterized by the criteria presented in The rate of development in UPV values was observed to be lower at early ages, but it gradually increased with respect to time. The specimen containing FA and BT presented a more significant development rate in UPV values than CC. The substitution of FC showed the same development pattern as CC, but a significant reduction was observed at 91 days. The BC showed continual development with respect to concrete age, which shows that the UPV values of these specimens progressively improved with time.Ternary blends of BT and FA presented a similar magnitude of UPV values at 56 days of curing. However, it was found to be higher in BC at later ages. At 91 days, the rate of development of samples was observed in the following order: BC > FBC > CC > FC. Generally, the value of UPV is influenced by the microstructure of concrete. The higher development rate in BC can be attributed to its improved microstructure. The fine particles of pozzolans eliminated the capillary pores by forming additional silicates during the pozzolanic reaction process.At 91 days, the cores of 101.6mm φ were taken out from mass concrete blocks. The core extraction pattern is shown in 2 coefficient of 0.826, 0.883, and 0.859 for inner cores, outer cores, and cylinder specimens, respectively. This showed a significantly strong relationship between the parameters. Less variation in UPV values was observed between the surface and central cores containing FA and BT. Hence, the binary and ternary blends of FA and BT presented the homogeneity of mass concrete specimens. A total of 12 surface cores and 10 central cores were taken out from each massive concrete block, having dimensions similar to the size of cylinders . The aveThe result obtained from variation in the temperature at the core of mass concrete samples is presented in The rate of temperature rise in FC was much slower than CC. The peak temperature was recorded as 18.8 °C after 19 h of casting. The rate of rise in the FBC was slower than CC, but compared to BC and FC, was comparatively higher. The peak temperature was recorded as 23.3 °C after 25 h of casting. The use of BT (BC) with 30% partial replacement of ordinary Portland cement showed a reduction in peak temperatures of 33%, whereas using fly-ash (FC) with similar replacement of ordinary Portland cement showed a reduction in peak temperature of 40.8%. The combination of Fly-ash BT (FBC) replacement showed a reduction of the peak of 27%. It has been reported that the substitution of 50% FA can lower the concrete peak temperature by 23%, whereas the individual substitution of FA at a moderate level (20–30%) may not contribute to significantly lowering the heat evolution in concrete . In this3) have been observed in the range of 430–550 °C and 550–650 °C, respectively [Differential thermal analysis (DTA) is a technique that observes the variation in the temperature of the specimen with respect to temperature or time. Generally, a difference in temperature is indicated by electric potential (µV). The Thermo-gravimetric (TGA) technique is used to measure the reduction in mass of a specimen with respect to temperature. The thermal decomposition of different phases in a material is identified through DTA analysis, whereas loss in weight due to decomposition is simultaneously measured thorough TGA. The TGA/DTA thermo-grams of CC, FC, BC, and FBC samples were analysed at the age of 28 days . The ideectively . The calcium hydroxide was consumed at a higher proportion across all specimens containing BT and FA at 28 days, which represents the formation of an increased amount of C–S–H due to the pozzolanic reaction. The addition of FA as a replacement for OPC in FC presented a hump at 550–650 °C, which shows the presence of crystalline silica. The loss in the mass due to the temperature of specimens containing BT and FA is presented in The reduction in CH weight of all specimens containing FA and BT presented lower values than CC. The percentage loss was calculated with these values against percentage loss in CC. The drop of CH amount in FC, BC, and FBC was calculated as 33%, 40%, and 28%, respectively. The partial substitution of FA and BT with OPC declined the formation of CH in the hydration products. This could be attributed to the consumption of CH during the pozzolanic reaction and dilution effect.The mineralogical compositions of BT and FA samples were analyzed by X-ray diffraction analyses at 28 days of curing. The peaks of calcium hydroxide (CH) and tobermorite, which is a crystalline form of calcium silicate hydrate mineral (C–S–H) , were anIn the control mix (CC), strong peaks of CH were observed, indicating that a pure hydration product was obtained from the cement hydration. In addition, lower crests of tobormorite were also seen. The substitution of FA retarded the CH peaks, and peaks indicating quartz were observed at 62.5° and 67.8°, which indicated the presence of crystalline silica in FA samples. The reduction in CH concentration is attributed to a decrease in the amount of cement and the pozzolanic reaction of FA. This caused the consumption of free CH available due to the presence of active silica to form a supplementary hydration product. The addition of BT further decreased the intensity of CH peaks. This can be attributed to two reasons. Firstly, a reduction in CH is due to the product of the clinker dilution effect that can be initiated by substituting the portion of cement with an equal quantity of BT. Secondly, BT forms a secondary calcium silicate gel by reacting with the hydrated lime OPC . The comThe morphological investigation of samples was analyzed through the scanning electron microscopic (SEM) technique. The micrographs of CC and concrete containing FA and BT separately and collectively are shown in (1)The development rate of compressive strength and UPV values in mass concrete samples were significantly improved with the substitution of BT and FA compared to control concrete.(2)Blends of BT and FA significantly retarded the rise in temperature in mass concrete specimens. Incorporation of FA presented a lower temperature among all the mixes, whereas BT was also found to be more effective to control the rise in temperature.(3)The XRD analysis revealed that a binary and ternary blend of BT and FA presented a significant reduction in CH peak intensity. This was due the reduction in the cement content and the pozzolanic reaction. The free CH was consumed by silica, which produced additional hydration product in the mix.(4)DTA/TGA investigations showed a significant reduction in CH amount in BT and FA samples due to the OPC dilution factor and pozzolanic reaction. The reduction in the CH amount of FC, BC, and FBC was calculated as 33%, 40%, and 28%, respectively.(5)Microstructural analysis through SEM offered a more refined pore-structure with the substitution of BT. The SEM analysis further showed that hydration in the BC and FBC mix consumed CH in the formation of the supplementary hydration product of C–S–H.This research evaluated the thermal, physico-chemical, microstructural, and mechanical behaviour of mass concrete using BT and FA separately and in combination. Four different types of mix ratios were prepared with the substitution of 30% BT, 30% FA, a combination of 15%BT-15%FA, and control mix. The data for binary and ternary blended mixes of BT and FA were obtained using an experimental investigation. The analysis of results was done by comparative analysis, in which the mix-of different proportions was compared with control mix. The following conclusions have been made from the analysis of the results:


MES-4 and MET-1, the two Caenorhabditis elegans enzymes that methylate H3K36 (histone H3 Lys 36). Mass spectrometry analysis confirmed immunostaining results showing that both MES-4 and MET-1 catalyze H3K36me3. In the adult germline, MES-4 is enriched in the distal mitotic zone and MET-1 is enriched in the meiotic pachytene zone. Embryos inherit H3K36me3-marked chromosomes from both the oocyte and sperm, and a maternal load of MES-4 and MET-1. Maternal MES-4 quickly associates with sperm chromosomes; that association requires that the sperm chromosomes bear H3K36me3, suggesting that MES-4 is recruited to chromosomes by preexisting H3K36me3. In embryos that inherit H3K36me3-positive oocyte chromosomes and H3K36me3-negative sperm chromosomes, MES-4 and H3K36me3 are maintained on only a subset of chromosomes until at least the 32-cell stage, likely because MES-4 propagates H3K36me3 on regions of the genome with preexisting H3K36me3. In embryos lacking MES-4, H3K36me3 levels on chromosomes drop precipitously postfertilization. In contrast to the relatively high levels of MES-4 in early-stage embryos, MET-1 levels are low at early stages and start increasing by the ∼26-cell stage, consistent with expression from the zygotic genome. Our findings support the model that MET-1 mediates transcription-coupled H3K36me3 in the parental germline and transcriptionally active embryos, and that MES-4 transmits an epigenetic memory of H3K36me3 across generations and through early embryo cell divisions by maintaining inherited patterns of H3K36me3.Epigenetic information contributes to proper gene expression and development, and can be transmitted not only through mitotic divisions but also from parents to progeny. We investigated the roles in epigenetic inheritance of  Failure to do either can lead to lethality, developmental defects, and cancer. Establishment and maintenance of different cell fates relies on a variety of mechanisms to generate different gene expression patterns between cells that possess an identical genome sequence. One mechanism is packaging sets of genes into chromatin states that are more or less accessible to the transcriptional machinery. The first level of DNA packaging into chromatin entails wrapping DNA around octamers of histone proteins . FurtherDrosophila     in embryos, MES-4 maintains H3K36me on those genes; and (3) delivery of chromosomes with H3K36me marking of germline-expressed genes to the primordial germ cells (PGCs) enables those cells to launch a proper germline transcription program.This report focuses on the generation and maintenance of H3K36me3, which is less well understood than H3K27me3. H3K36me3 is conserved from yeast to humans and is generally associated with actively expressed genes . The parmammals)  raises tmammals) . In thesmammals) . FurtherMET-1 and MES-4 action in C. elegans, focusing on H3K36me3. We show that both MET-1 and MES-4 contribute to H3K36me3. To our knowledge, this is the first example of two different HMTs contributing to H3K36me3  agar plates using Escherichia coliOP50 as a food source. Experiments were carried out at 20, 24, 25, 25.5, or 26.5°. Strains used for this study include:N2 (Bristol) as wild-type.fem-2(b245ts) III.DH0245 met-1(n4337) hT2-GFPI/ ; mes-4(bn73) dpy-11(e224) DnT1V/[unc(n754) let] .SS0875 mes-4(bn73) DnT1-GFPV/[unc(n754) qIs51let ] .SS1095 met-1(tm1738) hT2-GFPI/ .SS1139 met-1(n4337) hT2-GFPI/ .SS1140 jmjd-2(tm2966) II; jhdm-1(tm2819) III; mes-4(bn73) DnT1V/[unc(n754) let] .SS1278 met-1 ORF includes 14 exons. met-1(tm1738) deletes 656 bp that extend from the last AG of intron 3 to almost the end of exon 5 , and met-1(n4337) deletes 1860 bp that extend from almost the end of exon 5 to the first GT of intron 8 . Using an anti-MET-1 antibody directed against amino acids 1263–1362 , met-1(tm1738) eliminates MET-1 staining, met-1(n4337) does not.The longest met-1 mutant early embryos were thawed in 10 ml modified nuclei purification buffer (NPB) , then homogenized with a glass dounce homogenizer and 30 strokes of a tight-fitting pestle to free nuclei. Nuclei were enriched by pelleting cellular debris at 100 × g for 2 min at 4°, collecting the supernatant, adjusting the volume to 45 ml with modified NPB, pelleting residual debris at 100 × g for 5 min, and collecting the supernatant. Enriched nuclei were washed twice in modified NPB by centrifuging at 1000 × g for 10 min. Nuclei were resuspended in 400 µl 0.4 M NH2SO4, vortexed briefly to ensure nuclei were completely resuspended, and rotated overnight at 4°. Samples were centrifuged at 16,000 × g for 10 min at 4° to pellet insoluble debris. The supernatants containing histones were transferred to clean tubes and histones were precipitated by the addition of 100% trichloroacetic acid to a final concentration of 33%. Samples were rotated overnight at 4°, then centrifuged at 16,000 × g for 10 min at 4°. The pellets containing histones were washed twice with 1 ml ice-cold acetone. After the second wash, the pellets were allowed to air dry for 20 min at room temperature.The histone extraction protocol was adapted from 4OH to adjust the pH to ∼8.0. Samples were incubated for 15 min at 37°. Propionylation was repeated a second time after drying samples in a SpeedVac centrifuge. Samples were dried and resuspended in 50 mM NH4HCO3 overnight at room temperature with trypsin at an enzyme:sample ratio of 1:20. After digestion, the derivatization reaction was performed again twice to derivatize the N-termini of peptides. Samples were desalted using C18 Stage-tips before LC-MS (liquid chromatography-mass spectrometry) analysis. Samples were analyzed using a nanoLC-MS/MS setup. First, 1 µg of sample was loaded onto an in-house packed 75-μm ID × 20 cm Reprosil-Pur C18-AQ  nano-column using an EASY-nLC nano-HPLC . Peptides were separated with a linear gradient using two buffers: A = 0.1% formic acid, and B = 95% acetonitrile and 0.1% formic acid. Elution of histone peptides was achieved using a gradient of 0–26% buffer B over 45 min; then the column was washed by running from 26 to 80% buffer B over 5 min followed by isocratic 80% buffer B for 10 min. The flow rate was set at 300 nl/min. Nano-liquid chromatography (nLC) was coupled online with an Orbitrap Elite MS (Thermo Scientific). Runs were acquired using data-independent acquisition (DIA) as described (m/z 300−1100) were acquired in the Orbitrap at a resolution of 120,000  in between 16 MS/MS events spanning the m/z range, each acquired in the ion trap with an isolation window of 50 m/z. Fragmentation was performed by using collision-induced dissociation set at 35%. Raw MS data were analyzed using Skyline  fitted on a Nikon Eclipse TE2000-E inverted microscope  . All othThe quantification protocol used for met-1 heterozygous L4s were shifted from 20° to the experimental temperature . Their wild-type and met-1 homozygous L4 F1 progeny were picked to new plates, then scored for fertility ∼24-hr later. Selection of L4s for scoring prevented biased selection of fertile or sterile worms. Worms were visually scored using a Leica M80 stereo microscope. Worms containing embryos were scored as fertile and worms lacking embryos were scored as sterile. Worms that were not obviously fertile or sterile were picked onto individual plates, and scored as fertile if they laid embryos and sterile if they did not. Fertile wild-type and homozygous met-1 mutants were chosen from each generation to produce progeny to score in the next generation.To score fertility, wild-type and csr-1 . To genhttps://chorusproject.org, project number 1495. All strains and noncommercially available reagents are available upon request.MS raw data are available at MET-1-related HMTs in other organisms, Set2 in Drosophila and SETD2 in mammals, are thought to be fully responsible for H3K36me3  analysis of H3 tails from wild-type and met-1 mutant early embryos. Embryos bearing either of two deletion alleles of met-1  had robust levels of H3K36me3, which must be generated by a different HMT  and the H3 variant H3.3. Typically, canonical H3 is expressed and deposited exclusively during S phase (replication-dependent), while H3.3 is expressed throughout the cell cycle and is deposited at regions of active transcription (replication-independent)  .To determine the spatial and temporal pattern of H3K36me3 during germ cell development, we analyzed the distribution of H3K36me3 in germlines and gametes. Immunostaining of dissected germlines revealed chromosome-associated H3K36me3 signal in all germ nuclei, including mitotic and meiotic germ cells, and mature oocytes . ConsistMES-4 and MET-1 in the germline, we immunostained dissected germlines from met-1 and mes-4 mutant hermaphrodites. H3K36me3 was detected in met-1 mutant germlines, indicating that MES-4 generates H3K36me3 throughout the germline and in oocytes  at which some wild-type worms develop into sterile adults. Both met-1 alleles caused a small percentage of worms to develop into sterile adults at 25°. Even when cultured at 25° for three generations, only 0.9% of met-1(tm1738) and 3.1% of met-1(n4337) were sterile. In a second experiment, we observed a slightly higher level of sterility for met-1(tm1738) and met-1(n4337) at 25.5° after five generations, 5.6 and 4.0%, respectively  gamete but not the paternal (P) gamete (so M+P− embryos), the oocyte-delivered chromosomes were H3K36me3 positive and the sperm-delivered chromosomes were H3K36me3 negative  and are unable to produce zygotic MES-4 (Z-). These embryos inherited MET-1-generated H3K36me3. We quantified the intensity of H3K36me3 staining during prometaphase in one-cell- to eight-cell-stage embryos. For each genotype, we compared the average intensity in single diploid nuclei of two-, four-, and eight-cell embryos to the average intensity in the two juxtaposed haploid pronuclei in one-cell embryos. Staining of wild-type embryos revealed that the average intensity decreased from the one-cell stage (set to 100%) to the two-cell (71%), four-cell (59%), and eight-cell (42%) stages  to the two-cell (25%) and four-cell (5%) stages; staining was undetectable by the eight-cell stage (0%)  stages . In mes-age (0%) . In contcontrols . Therefomes-4 M-Z- embryos was greater than expected if the parental load of H3K36me3 was simply being diluted by rounds of DNA replication. Loss of H3K36me3 by dilution at each round of DNA replication would predict a drop of 50% at each subsequent stage, i.e., 100% at the one-cell stage, then 50, 25, and 12.5% in each nucleus at the two-, four-, and eight-cell stages, respectively. Even when we adjusted for the decrease seen in wild-type worms, the rate of loss in mes-4 mutants was still greater than the decrease expected by simple dilution, leading us to consider the possibility that H3K36me3 removal is an active process involving demethylation. Two different demethylases have been reported to target H3K36me3 in C. elegans: JMJD-2 and JHDM-1 may be involved or histone exchange may deplete H3K36me3.We noted that the rate of H3K36me3 loss in  embryos . These rMES-4 and MET-1 revealed different protein accumulation patterns. MES-4 is enriched in the distal mitotic region and the late pachytene region . If H3K36me3 is required for this de novo association, then sperm chromosomes lacking H3K36me3 should fail to recruit maternal MES-4. We mated feminized mothers with met-1; mes-4 fathers to generate M+P− embryos in which the oocyte-contributed chromosomes possessed H3K36me3 and the sperm-contributed chromosomes lacked H3K36me3. We did not detect MES-4 on the sperm-contributed chromosomes, which lacked H3K36me3, whereas MES-4 was highly enriched on the oocyte-contributed chromosomes, which were inherited with H3K36me3 marking . To test the possibility that MES-4 recruitment to sperm chromosomes involves CSR-1 or its associated small RNAs, we used RNAi to deplete CSR-1 from maternal germlines and early embryos. Successful RNAi against CSR-1 was confirmed by observation of enlarged and mislocalized P granules in one- and two-cell embryos, as well as lagging chromosomes during anaphase of the first cell division  H3K36me3 is transmitted via both sperm and oocyte to progeny, and through cell divisions in the early embryo; (2) two HMTs, MET-1 and MES-4, contribute to H3K36me3 in the germline and in embryos; and (3) maternally supplied MES-4 is responsible for maintaining inherited H3K36me3 in embryos. These data support the previously proposed model  to the mark it makes. For a histone mark to provide transgenerational memory, it needs to be established in the parent, transmitted to the progeny through meiosis and gametogenesis, survive postfertilization chromatin remodeling, and, finally, be maintained during embryogenesis until the appropriate cell type is formed. Evidence for all of these steps has been reported for C. elegans (H3K27me3 and H3K9me2/3 are known to be propagated by recognition of the mark by the enzyme complex that makes the mark [PRC2 for H2K27me3 and SU(VAR)3-9 for H3K9me2/3], and subsequent generation of more of the same mark on nearby nucleosomes , while MES-4 contains a sequence with only minimal similarity to an SRI domain at an atypical position (overlapping the SET domain) . Given that MET-1 appears to be primarily responsible for transcription-coupled H3K36me3 and likely is involved in the establishment of an epigenetic memory of gene expression in parental germ cells, it is noteworthy that met-1 mutants are generally healthy and fertile. MES-4 may well contribute to transcription-coupled H3K36me3 in the germline, although previous results suggest that in embryos it cannot generate H3K36me3 de novo but instead is devoted to a maintenance role (In contrast to the maintenance activity of Drosophila PRC2 and H3K27me3 also includes antagonism, or antirepression, by trithorax group proteins (MES-4 and methylated H3K36 antagonize deposition of H3K27me3 (In vitro assays demonstrate that PRC2 is unable to methylate nucleosomes with preexisting H3K36me2 or me3 (MES-4 develop into sterile adults, possibly because the memory of expressed germline genes is not delivered to the PGCs. One likely consequence of losing the memory of gene expression is the encroachment of H3K27me3 and the inappropriate silencing of genes required for the germline developmental program. Indeed, depletion of MES-4 from embryos leads to loss of H3K36me3 from germline genes and the acquisition of H3K27me3 on those genes (mes-4 mutants may be the result of inheriting an altered epigenome, silencing of genes required for germline development, and inappropriately expressing genes not normally expressed as part of the germline program.The paradigm of heritable epigenetic repression mediated by C. elegans, it is clear that the MES chromatin factors PRC2 and MES-4 function antagonistically across generations to promote germline development. It is likely that the patterns of H3K27me3 and H3K36me3 inherited by the PGCs serve to guide gene expression patterns as they do during Drosophila embryogenesis. To test this possibility, ongoing work is aimed at analyzing the gene expression changes in C. elegans PGCs that did not inherit MES memory from parent worms.Maintenance of gene expression patterns is required to ensure that cell fates are maintained. If cells within a tissue lose or change fate, the function of that tissue may be compromised or become cancerous if cells revert to a proliferative state. A memory that is transmitted across generations could influence not only the development of the inheriting organism, but also the fitness of the species as a whole. This is an exciting possibility, and current efforts are focused on determining if environmental factors can change the epigenome, if and how changes are transmitted to progeny, and if such changes influence development in subsequent generations. In


Global economic growth causes an increase in natural resources exploitation, particularly in construction branch. The growing use of electricity contributes to climate change. Therefore, it is necessary to search the solutions, which will allow for reducing natural resources exploitation. One of the many opportunities to do that is the application of the recycled materials. The authors of the given article have analyzed three variants of construction solutions. One of them was the production of the walls of a building from reinforced concrete prefabricates with styrofoam insulation layer. The second variant for analysis were prefabricated walls from lightweight concrete, made of sintered clay aggregate with a foam core. The third proposed variant was a system of multi-layered walls, which was made of lightweight concrete with granulated expanded glass aggregate (GEGA). The main objective of the research was to assess the use of lightweight GEGA prefabricates, focusing on economic and technological aspects of the solution. The authors have analyzed the entire construction costs; ceilings and stairs were assumed as reinforced concrete elements. In calculations, the weight of the elements was taken into account, as well as transportation and mounting costs. On the basis of this cost analysis, it was concluded that the use of prefabricated element, made of lightweight concrete with GEGA, could be a replacement for the solutions, widely applied until these days. The analysis has also shown that the use of prefabricates with GEGA is sensible from the economic viewpoint, as it allows for saving construction time. Moreover, the solutions, proposed here, allow for saving natural resources and assuming a more environmentally friendly and caring attitude. Science and technology development enable the implementation of innovative solutions in construction and architecture. Multiple changes in concrete production and prefabrication are being introduced. At present, concrete as a modern composite is regarded not only as a construction material, but also as an insulation material or aesthetic architectural finish. Concrete properties depend on concrete mixture components.Concrete technologists face increasing expectations, as more and more modifications of both ready-mix and prefabricates become possible to be made, maintaining material’s durability and strength at the same time. It is also possible to modify cement binder by means of applying admixtures and additives or natural, artificial, or recycled aggregates alongside with sustainable development principles while obtaining components, producing ready-mix and prefabricating elements.3 and not more than 2000 kg/m3 volume density in a dry state and with strength from LC 8/9 to LC 80/88. High strength lightweight concrete is a concrete with compression strength that is higher than LC50/55. Currently, due to the possibility of the use of the additives and chemical admixtures, it is possible to obtain considerably higher strength parameters for lightweight concrete than is required by the standard. Lightweight concrete and its modifications are subject to a great number of research at the moment [3 shows thermal insulation properties that are similar to those of ceramic brick wall [New technologies in artificial lightweight aggregate production enable meeting complex requirements of the construction contractors as for strength, insulation, acoustic, fire-resistance, and aesthetic properties. According to , lightwee moment ,5,6,7. De moment ,11. Lighick wall ,13. The ick wall ,15,16. Tick wall ,19,20,21Prefabrication gives great opportunities for public, residential, and industrial construction. The essence of this technology lies in the optimization of construction process, safety procedures improvement, limitation of the waste production, and minimization of exhaust gas emission. Moreover, the search of the effective methods of construction project realization in keeping with the aesthetic and comfort values of the constructed object is of high importance. The aim of prefabrications is saving construction time, reduction of the number of construction processes, minimization of construction’s cross section, and quality improvement ,23,24,25The prefabricated multi-layer wall is frequently used in the prefabricated integrated residential buildings, which are characterized by easy installation and short construction time ,28,29. FFurther analyzing the case of installing prefabricated walls in an apartment building, thermal conductivity aspects were considered. Heat transfer coefficient for the walls was determined, while taking into account higher requirements, connected with thermal insulation in the countries with occurring problem of significant indoor and outdoor temperature difference. 2·K). In the case of outer walls, depending of the assumed temperature for calculations, the coefficient U = 0.3 W/(m2·K) or U = 0.8 W/(m2·K). These requirements cannot be met by one-layer reinforced-concrete wall or brick wall. One could apply a thermal insulation layer of foam panels or mineral wool or use thermal insulation plaster in order to meet the latter thermal insulation requirements. However, these solutions will generate additional costs and will make the walls thicker. Additional construction works, connected with thermal insulation, will cause construction deadlines prolongation. Therefore, an alternative solution lies in using multilayer prefabricated elements, which are made of lightweight concrete.According to the regulations, connected with thermal insulation of the buildings, the maximum total heat transfer coefficient of the walls between the corridors and apartments constitutes U = 1.0 W/.1, d2, … di—element thickness (cm)d1, λ2, … λi—thermal conductivity coefficient (W/m·K)λwhere:TR—total thermal resistivity (m2·K/W)Rsi—thermal resistance on the inner surface, (m2·K/W)R1, R2, … iR—each layer’s thermal resistivity values, (m2·K/W)seR—thermal resistance on the outer surface, (m2·K/W)The total thermal resistivity Heat transfer coefficient was calculated according to the Equation (3).siR, seR [The values of thermal resistance Rsi, Rse ,33 were Heat transfer coefficient of the wall was calculated according to the Equation (4).max could not be higher than 0.2 (W/(m2·K)).The main assumption was the maximum heat transfer coefficient UThe research of different variants of the project realization and the proposal of the optimal one leads to the choice of the best solution from the point of view of the chosen criterion. The aim of the alternative solution analysis is, among others, to answer the question, if the new technology or material implementation is beneficial from the investor’s/manufacturer’s point of view and if it leads to the cost reduction and/or production time saving ,35. In tIn order to optimize costs, it is advised to prepare construction cost estimation, including all costs calculation  for the solutions in question. In the case of time optimization, it is necessary to analyze workload for each process within the proposed solutions.The objective of the analysis, presented in the following part of the article, is to compare the labor cost and time needed for mounting the elements of the construction. Three solutions have been proposed, for which the costs and time of realization were analyzed.The object was selected, the bill of quantities was prepared, assumptions for calculation were made, and a cost-estimate calculation was carried out in order to determine the cost of raising a building in a raw state by means of prefabricated technology and the use of three types of materials. Three solutions were analyzed.The aforementioned methods were applied on an actual construction site. Subsequently, the economic, environmental, and social benefits of prefabricated concrete application in residential construction were analyzed.Solution 1 consists of assembling the object from prefabricated reinforced concrete elements, which are traditionally reinforced with two steel meshes from main bars ϕ10 mm every 10 cm  and from distribution bars ϕ8 mm every 15 cm . A sandwich wall contains an insulating layer of polystyrene. In addition, the wall has elements for transporting and arranging elements. Solution 2 is an assembly of the object, using prefabricated layered elements, with a lightweight concrete core of sintered and expanded clay (Leca). Wall elements are reinforced with two steel meshes from main bars ϕ10 mm every 15 cm  and distribution bars ϕ6 mm, laid every 15 cm . In addition, the wall has transporting and arranging elements. 3. The wall has elements, which enable the transport and arrangement of elements. Solution 3 consists of assembling the object with sandwich elements with a lightweight concrete core from granulated expanded glass aggregate, with an insulating layer of ultra-light concrete containing perlite and granulated expanded glass aggregate from the outside. Gypsum plaster was used in the inside. The wall reinforcement was designed with the 8 mm main bars every 15 cm  and with ϕ6 mm distribution bars being laid every 15 cm . In addition, lightweight reinforced polymer structural fiber reinforcement was used in the amount of 2 kg/mIn 2. The built-up area is 520.80 m2, the building has a cubature of 8900.60 m2, and the total area is 2983.40 m2 . The building is constructed of prefabricated elements in large-panel technology. The structural arrangement of the load-bearing walls is transverse, their spacing is 3.0 and 4.8 m. On the last storey of the building, masonry, prefabricated, and wet cast elements were used. Foundation benches are of reinforced concrete, wet cast from C30/37, concrete, and exposure class XC2. Structural walls of the underground and above-ground storeys are made of 15 cm thick prefabricated reinforced concrete elements.As an example, a multi-family, five-story, three-frame residential building was subjected to economic, technological, and organizational analysis . There aOn the basis of the project documentation, a bill of quantities (BOQ) was prepared, the range and quantity of certain works, needed for the raw object state, were determined. On that basis, an investor’s cost-estimate calculation was done in a simplified version. In both BOQ and estimation the production cost of the walls, ceilings and stairs were calculated . The assSolution 1Prefabricated reinforced concrete : 486.42 monetary unitsSolution 2Prefabricated items from concrete products made of sintered and expanded clay aggregate  and prefabricated reinforced concrete (ceilings and stairs): 494.75 monetary unitsSolution 3Prefabricated products that were made of lightweight concrete with GEGA  and prefabricated reinforced concrete (ceilings and stairs): 512.87 monetary units.Price per unit: Based on the cost calculation, prepared by means of the simplified method and prices from the third quarter of 2019 from the Sekocenbud price list  and prodThe cost of making the above range of the building shell  from reinforced concrete precast elements is 998,855.19 (monetary units). The cost of the same scope of works from precast lightweight concrete, which was made of sintered and expanded clay, is 1,039,454.82 (monetary units). The cost of prefabricated lightweight concrete works is 1,128,065.67 (monetary units). Solution No. 2 is 4.1% more expensive than solution No. 1, while solution No. 3 is more expensive than solution No. 1 by 12.9%. .The expenditure of time given in Based on the information contained in The analysis, carried allows for formulating the following conclusions.1. In practice, it is possible to use a prefabricated building, made of lightweight concrete, while maintaining all of the requirements for the construction of a building. This solution, in a broader context, finds technical and economic justification for its implementation in practice. It is possible to achieve time savings of up to 5% when compared to the assembly of a reinforced concrete precast object (solution 1).2. The main advantage of using broadly defined prefabricated technology (compared to monolithic technology) is the significant time saving that results from the incorporation of ready-made construction products. The analysis, as presented in the article for the three solutions, involving the facility assembly from ready prefabricated elements, showed that, depending on the type of applied material, of which elements are made, it is possible to achieve a shorter implementation time of a given scope of construction works. With large-scale works, it is possible to achieve significant savings in investment implementation time. This applies to the prefabricated transport process to the construction site. It is possible to transport a larger number of them by the transport unit at one time due to the lower weight of the elements, made of lightweight concrete, which in turn also speeds up the delivery and assembly time on site, reduces fuel consumption, and achieves lower material transport costs. Solution 3, therefore, reduces investor’s expenses in this area and significantly increases the pace of works at the construction site. In practice, the choice of solution 1 from three presented ones is associated with the lowest cost for the investor, but the longest time of work performance—embedding prefabricated elements.2 emissions in the process of manufacturing prefabricated elements and their transport to the construction site, and thus reduces environmental degradation [3. Solution 3 includes energy saving and the efficient use of raw materials in the production and assembly of prefabricated elements. It fully fits in with the idea of environmental protection and sustainable development of the economy ,43. Its radation . The impradation ,46, incl4. The use of technology using solutions 2 and 3 affects the highest quality of performed work and ensures optimal thermal conductivity and fire resistance.5. In construction practice, the integrated assembly of prefabricated elements, made of lightweight concrete, has not yet gained great interest. The numerous, also long-term benefits of using solution 3 should, however, encourage investors to choose and make extensive use of precast lightweight concrete, despite their higher price.


Fibre-reinforced polymer (FRP)-reinforced concrete members exhibit low ductility due to the linear-elastic behaviour of FRP materials. Concrete members reinforced by hybrid FRP–steel bars can improve strength and ductility simultaneously. In this study, the plastic hinge problem of hybrid FRP–steel reinforced concrete beams was numerically assessed through finite element analysis (FEA). Firstly, a finite element model was proposed to validate the numerical method by comparing the simulation results with the test results. Then, three plastic hinge regions—the rebar yielding zone, concrete crushing zone, and curvature localisation zone—of the hybrid reinforced concrete beams were analysed in detail. Finally, the effects of the main parameters, including the beam aspect ratio, concrete grade, steel yield strength, steel reinforcement ratio, steel hardening modulus, and FRP elastic modulus on the lengths of the three plastic zones, were systematically evaluated through parametric studies. It is determined that the hybrid reinforcement ratio exerts a significant effect on the plastic hinge lengths. The larger the hybrid reinforcement ratio, the larger is the extent of the rebar yielding zone and curvature localisation zone. It is also determined that the beam aspect ratio, concrete compressive strength, and steel hardening ratio exert significant positive effects on the length of the rebar yielding zone. The corrosion of steel reinforcement ultimately causes the loss of serviceability or the strength failure of reinforced concrete (RC) structures. Noncorrosive fibre-reinforced polymer (FRP) is an alternative to steel reinforcement for concrete structures ,6,7,8,9.Alternatively, the structural performance of concrete beams can be improved by a combination of FRP and steel reinforcements. An improved durability compared with RC beams is also likely to be obtained by placing FRP rebars at the corners or near the extreme tension face . MultiplNumerous tests have been carried out on the plastic hinge of RC members, and many plastic hinge length models have been proposed ,32,33,34This study is an attempt to assess the plastic hinge problem of hybrid reinforced beams through finite element analysis (FEA). Firstly, a finite element model is proposed, so as to validate the accuracy of the numerical method. The effect of the hybrid reinforcement ratio on the lengths of the three plastic hinge regions is analysed in detail. Subsequently, the influence of the main parameters on the plastic hinge lengths of hybrid reinforced beams is evaluated through parametric studies.The general finite element software ABAQUS  is used The four-node linear plane stress quadrilateral element CPS4R in ABAQUS is employed for the concrete elements. The mesh size of the concrete element is 20 mm. Elements smaller than 20 mm make little difference to the results, according to the mesh convergence model.tf refers to the tensile strength; fG is the fracture energy of concrete; and bh is the crack band width and was taken to be A is the total area of the element [fG is expressed by the following:cof is the concrete compressive strength, and ad is the maximum size of the coarse aggregate and is considered to be 20 mm in this work.The damaged plasticity model is adopted to model the material behavior of concrete. The ascending section of the tensile relationship is assumed to be linear, and the softening is assumed to be exponential, as shown in  element . The fracσ and cε are the compressive stress and strain of concrete, respectively; cof is the peak stress; coε is the strain at cof; and cE is the elastic modulus of concrete.For concrete under compression, the widely used stress–strain model proposed by Popvics  is used Poisson’s ratio is assumed to be 0.2 and the dilation angle is selected to be 55° for concrete. The following default plastic parameters are used for concrete in ABAQUS: 0.1 for eccentricity, 1.16 for the ratio of the initial equi-biaxial compressive yield stress to the initial uniaxial compressive stress, and 0.6667 for the ratio of the second stress invariant on the tensile meridian to that on the compressive meridian.sσ and sɛ are the stress and strain of steel, respectively; yɛ is the yield strain of steel; sE is the elastic modulus of steel; and shE is the hardening modulus of steel. FRP reinforcement is treated as a linear-elastic material, where the stress increases linearly with the increasing strain.A two-node truss element, T3D2 in ABAQUS, is employed for the steel reinforcement and FRP reinforcement. The bilinear model, which considers strain hardening, is adopted to model the stress–strain relationship of the steel reinforcement . The strτ is the bond stress, and sl is the distance between the spring elements, which is the same as the mesh size of 20 mm. It is noted that the nonlinear springs are used only for longitudinal reinforcement. The transverse reinforcement is treated as the embedded elements in ABAQUS. For more details, please refer to the previous literature by the first author [The Spring2 element is used to define the nonlinear bond–slip relationship between steel/FRP reinforcements and concrete. The reinforcement nodes are connected with concrete nodes by a series of springs. A very large stiffness is employed for the springs in the normal direction of the interface, to ensure the same deformation in the direction of the reinforcements and the concrete. In the tangential direction, the bond–slip relationship proposed by Wu and Zhao  is emplot author ,43.Four concrete beams reinforced with hybrid FRP–steel bars are simulated. fA and sA are the reinforcement areas of FRP and steel, respectively. Herein, the total tension reinforcement ratio is fixed to be 1.6% of the four beams. The FRP reinforcement ratios are selected as 0, 0.4%, 0.8%, and 1.2%, corresponding to the hybrid reinforcement ratios of 0, 0.33, 1, and 3, respectively. All of the specimens exhibit identical geometric dimensions and material properties. A typical cantilever beam is investigated in the present study, as shown in b × h = 200 mm × 400 mm. The distance from the middle section to the support point (z) is 2000 mm  reinforcement are as follows: elastic modulus fE = 160 GPa and ultimate strength fuf = 2400 MPa. The concrete compressive strength cof = 30 MPa.This section describes the analysis of the influence of the FRP reinforcement ratio on the development of the plastic hinge regions for hybrid FRP–steel reinforced concrete beams. Four hybrid reinforced beams with identical total reinforcement areas, albeit different hybrid reinforcement ratios, are selected for the analysis. The hybrid reinforcement ratio defined by Qin et al.  is used  2000 mm . The matrρ = 0), an evident dividing point exists in the steel strain distribution curves. The rebar strains on the left side of the dividing point attain or exceed the yield strain and grow dramatically with an increase in the drift ratio. However, on the right side of the dividing point, the rebar strains are lower than the yield strain and remain almost constant as the drift ratio increases, as shown by the longitudinal rebar strain distributions for the specimens at each drift ratio level in syL), as shown in For a beam reinforced only by steel , the difference between the maximum moment and the yield moment remains constant after the load carrying capacity is attained. In this case, the distance from the yield section to the maximum moment section (mid-span section in this study), which is known as syL, remains constant after a specific displacement. However, for the hybrid reinforced concrete beams (rρ > 0), the yield moment occurs at a fixed displacement, whereas the moment resistance continues to increase, owing to the linear-elastic property of the FRP reinforcement. In this case, the gap between the maximum moment and the yield moment continues to increase as the drift ratio increases, resulting in an increasing syL. The higher the hybrid reinforcement ratio, rρ, the more significant the increment of syL. On the one hand, the yield moment decreases with the increasing rρ, owing to the smaller steel reinforcement layout. On the other hand, the maximum moment continues to increase as rρ increases, owing to the higher tensile strength of the FRP reinforcement compared with that of the steel reinforcement. As a result, the gap between the mid-span moment and the yield moment grows larger, as illustrated in syL increases by 265% at a drift ratio of 2% when rρ changes from zero to 0.33, compared with 308% and 351% when rρ varies from zero to one and three, respectively [The steel strain variation trend of the hybrid FRP–steel reinforced concrete beams are completely different from that of the RC beam, as shown in ectively ,47.RC with hybrid FRP–steel rebars guarantees a greater ultimate deformability and deflection than RC with only steel rebars, but it does not guarantee more ductility. The reason the ultimate displacement of the former is greater than that of the latter has not been explained by the authors, which is a serious flaw. The reason is that when the behavior of the steel rebars is plastic, the behavior of the FRP rebars is linear-elastic, so the inelastic part of the moment–curvature diagram is a steep curve up to the final level. On the contrary, the inelastic part of the moment–curvature diagram of a steel section is flat. Therefore, in the former case, the length of the plastic hinge is greater than in the latter case, and the ultimate displacement is also greater. Nevertheless, that behavior consists of deformability not ductility, as the beam with hybrid rebars does not dissipate more than the beam with the steel rebars ,47.csL) was always selected for analysis [analysis ,42,43.csL is not affected by rρ. As rρ increases, the concrete strength remains constant and the compression failure zone remains almost constant, resulting in a stable csL.tε and cε are the strains at the extreme tension fibre and extreme compression fibre, respectively, and h is the beam depth. It can be found from pcL [from Lpc ,42,43.rρ on pcL. It is evident that the dividing point shifts away from the mid-span section as rρ increases, indicating a larger pcL for a higher rρ. For example, pcL increases from 82 mm to 142 mm when rρ changes from zero to three. It is inferred from Equation (11) that the curvature is associated with both the concrete compression strain and the tension strain. As a result, the curvature localisation is caused by concrete crushing as well as steel yielding. As syL and csL increase with the increase in rρ, pcL subsequently exhibits a similar increasing trend.pcL at a higher rρ is accompanied by the more uniform curvature distributions. pcL exhibits a larger curvature in the mid-span section, and that a larger plastic hinge length yields a smaller mid-span curvature. For example, at the drift ratio of 2%, the mid-span curvature of the beam with rρ = 0 is 0.000219, compared with 0.000176, 0.000157, and 0.000144 for rρ = 0.25, rρ = 0.5, and rρ = 0.75, respectively. This implies that at an identical displacement level, the hybrid beam with a higher hybrid reinforcement ratio exhibits a smaller mid-span curvature demand than that with a lower hybrid reinforcement ratio. Moreover, for a smaller curvature demand, the residual displacements would be smaller for the hybrid beams with a higher hybrid reinforcement ratio, owing to the self-centering behaviour of the FRP reinforcements; this results in an improved reparability of structures after a severe seismic event.At an identical drift ratio, the larger rρ on syL, csL, and pcL are displayed together in syL is determined when the maximum concrete compression strain attains 0.008 for hybrid FRP–steel reinforced concrete beams. It can clearly be seen from csL remains almost constant, whereas both syL and pcL exhibit increasing trends when rρ increases. The growth rate of syL is more pronounced than that of pcL.The influences of the hybrid reinforcement ratio z/h; concrete compressive strength, cof; yield strength of steel reinforcement, yf; steel reinforcement ratio, sρ; steel hardening ratio, shE; and elastic modulus of the FRP reinforcement, fE. The control beam has a steel reinforcement ratio of 0.8% and an FRP reinforcement ratio of 0.8%. The geometric dimensions and material properties of the control beam are identical to that provided in In order to gain a comprehensive understanding of the plastic hinge regions of hybrid FRP–steel reinforced concrete beams, a systematic parametric study has been carried out. The main influential parameters include the aspect ratio, z/h from three to eight was achieved by increasing the effective length, z, while fixing the beam depth, h, at 400 mm. syL and pcL increase rapidly, whereas csL remains almost constant as z/h increases. Theoretically, the distance from the maximum moment section to the yield moment section, denoted as syL, is proportional to the beam length, as shown in In the present study, the variation in cof, on the lengths of the plastic hinge regions of the hybrid reinforced concrete beams. cof varies from 20 MPa to 60 MPa. It is evident that syL exhibits an increasing trend, whereas csL exhibits a decreasing trend as cof increases. As cof increases, the compression zone is strengthened; thus, a larger tension resultant force is necessary to balance the increasing compression force, resulting in a larger maximum moment and thus a larger syL. pcL increases marginally as cof increases, indicating that, in this case, pcL is governed by the steel yielding zone. As the ultimate curvature, which is defined by the ratio of the ultimate compression strain (0.003–0.0035) to the height of the neutral axis, keeps almost constant, a larger plastic hinge region leads to a higher ultimate deformation.The numerical results in yf, is considered to affect the plastic hinge zones and was included in the most widely-used plastic hinge length model of the RC members, proposed by Paulay and Priestley [yf on the plastic hinge lengths of the hybrid reinforced concrete beams is presented in syL decreases, whereas csL increases as yf increases. As yf increases, the tension zone is strengthened and the compression of concrete enters into the ultimate state, as described earlier, resulting in a smaller syL. Meanwhile, the yield moment increases as yf increases, which implies a lower ratio of the maximum moment to the yield moment, and thus a smaller syL. Owing to the coexisting effects of syL and csL, pcL remains almost constant as yf increases.The yield strength of the steel reinforcement, riestley . The effsρ, on the extent of the plastic hinge regions for the hybrid reinforced concrete beams. The FRP reinforcement ratio is fixed to be 0.8%, whereas the steel reinforcement ratio varies from 0.2% to 1%. It can be found from syL decreases rapidly as sρ increases, whereas csL remains almost constant as sρ increases. On the one hand, the tension zone of the beam is strengthened as sρ increases, resulting in a smaller syL. On the other hand, the larger sρ results in a smaller gap between the maximum moment and the yield moment, which further reduces syL. pcL is determined by syL and thus exhibits a decreasing trend as sρ increases.shE on the plastic hinge lengths of the hybrid reinforced concrete beams is shown in syL, c,sL, and pcL, exhibit increasing trends as shE/sE increases. The mechanism is extremely straightforward and can be explained as follows: as shE increases, the yield moment remains constant, whereas the maximum moment increases, which implies a larger extent of the rebar yielding zone, as illustrated in the moment distribution diagram in The effect of the steel hardening modulus fE, on the plastic hinge lengths of the hybrid reinforced concrete beam. Four elastic modulus values, 40 GPa, 80 GPa, 120 GPa, and 160 GPa, have been selected for analysis. It can be seen from syL decreases as fE increases. On the one hand, as fE increases, both the yield moment and the maximum moment increase and their ratio remains almost constant, which marginally affects syL. On the other hand, the tension zone is strengthened as fE increases, which has a negative effect on syL. This results in a smaller syL for a larger fE. The variation trend of pcL remains consistent with syL, which decreases as fE increases.syL, of the hybrid reinforced beams is significantly different from that of normal RC beams. syL continues to increase with the increase in displacement for hybrid reinforced concrete beams, whereas it is limited to a certain value for normal RC beams.The variation trend in the length of the rebar yielding zone, syL, owing to the moment redistribution along the beam length. The curvature localisation length, pcL, increases rapidly, whereas the concrete crushing length, csL, remains almost constant as the hybrid reinforcement ratio increases.The hybrid reinforcement ratio exerts a significant positive effect on Under an identical displacement level, the hybrid beam with the larger hybrid reinforcement ratio exhibits a mid-span curvature demand and residual displacements smaller than those with a lower hybrid reinforcement ratio.z/h, cof, and shE exert positive effects on syL and pcL. yf and shE exert positive effects on csL, whereas z/h, sρ, and fE exert negligible effects on csL.Among all of the parameters, This study examines the plastic hinge lengths of hybrid FRP–steel reinforced concrete beams, which have not been investigated extensively in previous studies. Firstly, a finite element model was proposed, and the accuracy of the model was verified by comparing the numerical results with the test results. Subsequently, three plastic hinge regions, including the rebar yielding zone, concrete crushing zone, and curvature localisation zone, were analysed in detail. The influence of the beam aspect ratio, concrete grade, steel yield strength, steel reinforcement ratio, steel hardening modulus, and FRP elastic modulus on the lengths of the three plastic zones have been studied through parametric studies. The effect of the FRP reinforcement ratio on the deformability and ductility of the hybrid reinforced concrete beams is also thoroughly discussed. The following conclusions can be drawn from the present study:


Reinforced concrete is of vital importance in many civil and industrial structural applications. The effective bonding between steel and concrete is the core guarantee of the safe operation of the structures. Corrosion or other interface debonding in steel-concrete is a typical failure mode during the long service period of the structures, which can severely reduce the load-bearing capacity. The Non-destructive Evaluation technique has been applied to civil engineering structures in recent years. This paper investigates the evaluation of reinforced concrete structures that have interface defects, including the cross-sectional loss and cracks, by using the piezoceramic induced ultrasonic wave and time reversal method. Ultrasonic wave is used as actuating wave to obtain the signals with defect information. Time reversal method is applied to localize and characterize defect along the interface of the steel-concrete and to image the defect through the cross-sectional scanning. Experiments were conducted to perform Nondestructive Evaluation by using six reinforced concrete components with different levels of defects. The invisible damages were made by the cutting part of the steel and embedding a table tennis ball inside concrete structures. The results show that the time reversed method can locate and evaluate the defects along the steel reinforced concrete, and the obtained defect images at the cross-section of the concrete structure are accurate. Concrete is the most widely used construction material in civil engineering due to its long service life and durability in harsh environments . This maThe time reversal method (TRM) is applied to damage detection or source locations in different reinforced concrete fields. Prior time reversed method studies focus on filtering single events out of recordings of low signal to noise (S/N)-ratio  or on thOn the other hand, researchers also apply the ultrasonic wave technique to detect defects in reinforced concrete. Ultrasonic wave velocity is applicable to concrete cast inside a form and is often used to detect flaws and evaluate the compressive strength of hardened concrete . The damDI) and the determination of the location of the defect can be executed by the wave velocity and the time-of-flight. Then the ultrasonic probes were located at the certain position of the concrete surface to image the defect. At the end of the paper, experiments of the time reversed method imaging of artificial defects inside the concrete structures were conducted and results demonstrated the accuracy of the proposed imaging method.The purpose of this paper is to detect the interface defects of reinforced concrete structures and to obtain the cross-sectional defect image. By using piezoceramic transducers, the pre-set interface defects can be identified by using time reversed method damage index  Stress wave equations in concrete structuresLC and S-wave TC can be respectively calculated as,The defects are present inside of the concrete samples, and the ultrasonic probes are located at the outer surface of the experiment samples. P-waves and S-waves are the main efficient ultrasonic waves that propagate in this infinite solid. Based on the material parameters listed in (2) Longitudinal mode wave selection in reinforced concrete structuresGuided waves propagate in cylindrical structures, such as pipes and cylindrical rods . By geneAccording to the material parameters of the experiments in H(t) is the Heaviside function, A is the amplitude, cf is the Central frequency and n is the number of the cycles of the signal.A 5-cycle burst signal was used as the excitation signal, as shown in S(t) is applied to the transducer at A side (Step 1), activating a wave signal that is captured by the transducer at the B side as R(t) (Step 2); the captures signal is time-reversed in the time domain as S’(t) = R(−t)) (Step 3) and reapplied to B’ side which is an intact cylinder; then the wave signal at the A’ side is collected and reconstructed of the original signal R’(t).The time reversed method in the axial direction of the reinforced concrete specimen is divided into two parts. One is the forward step which is performed in the defected specimen, and the reversed step is simulated in the same geometry as the defected one but in the intact specimen. The principle of the time reversed method in a two-dimensional cylinder is illustrated in S(t) is applied to generate a signal at the concrete surface; then the signals are captured by transducers on the same side as the generated one and each side takes this step (Step 2); the obtained signals are reversed in the time domain as S’(t) = R(−t) (Step 3) and regenerated at the same side where it comes from; then the wave signals are collected again and reconstructed as the original signal R’(t).The wave propagation in the concrete is the body wave and the ultrasonic probe is used to actuate and receive signals on the surface of the concrete. In When the wave propagates in concrete, the wave scatters when it encounters a defect and the scattered wave containing the damage information would be received by the transducers on the outside surface of the specimen.DI) can be defined using the characteristic of wave signals in the time domain. In the time domain, the changes between the input tone burst S(t) and the reconstructed signal after time reversal R’(t), and the correlation coefficient ia represents the actuated signal, ib represents the reconstructed directed signal, n is the wave element in the time-domain. In this way, the higher the DI, the greater the possibility of the existence of the damage in the wave path is evaluated.The Damage Index (tion (3)  and the DI value is beyond the threshold, the image based detection takes place. Since the location along the Z-direction of the reinforced concrete specimen can be calculated by the time-of-flight, the transmitters can be relocated at the four sides of the concrete cross-section. In order to image the defects inside the reinforced concrete specimen, the received signals can be reversed in the time-domain to regenerate in the intact samples in COMSOL. By observing the reversed wave propagation, the maximum of the displacement field can predict the defect location. In addition, one-side-time reversed method can identify the direction of the defect and time reversed method from four sides can relatively depict the boundary of the defect, as shown in maxI represents the pixel in the detecting plane and iu represents the displacement field in the revered time domain. For every point in the detecting section, the displacement field in the time reversed method progress can locate the defect or the signal source during the time period.When the DI value of each reinforced concrete specimen. If the DI value is larger than the threshold, then the reinforced concrete specimen is regarded as the defect sample.The severity and the location of the defect are unknown since the damage is inside the structure and the detection is divided into two steps, which are depicted in In the first step of the detecting system, as shown in DI value can be calculated by comparing the reconstructed directed wave and the input wave in the same period. Furthermore, the second detecting step was applied. The ultrasonic probe was placed on the outer surface of the concrete at Z = 250 mm.The overall experimental setup is shown in Attention should be paid that to the fact that, in the experiments, the value of the amplifier should be the same each time to maintain the same experimental condition to eliminate errors in identifying the defect reflecting signal.We repeated the experiment more than three times to gain stable received signals. DI values are plotted in DI value increases with the depth of the defect on the steel reinforced concrete. The horizontal axis represents the cross-section loss caused by defects and the vertical axis is the calculated DI value. The dots represent the DI value of each reinforced concrete specimen and the line represents the fitted result based on each dots. In this experiment, the defects were set along the interface of the steel-concrete and the defect depths were comparatively larger than the real structures. On the other hand, the oDI value is different for each structure since the proportion and the construction condition may differ for different structures.The reconstructed signals are calculated in Equations (4) and (5). The experimental results of the −5 s The calculated location of the defect was 250.04 mm and the error was equal to zero.The location of the defect can be identified by the time-of-flight (TOF) of the defect reflected signal. In this experiment, the defect in the six reinforced concrete samples was the same distance from one end surface of the steel rod so that the TOF of the defect was the same as 6.58×10Then the ultrasonic probe was placed on the outer surfaces of both the intact and defected specimens to compare the effects of the interface damage on the received signals. −4 s. In In this section, two defects inside the concrete specimens without steel are discussed to confirm whether the time reversed method can image and locate the two defects using UT. In the simulation, we pre-set two signal sources reinforced concretes located at  and , respectively. There are seven sensors at each side of the concrete boundaries to receive signals and they are regenerated at each location to trace the signal sources reinforced concretes. The time reversed method process is the same as detecting concrete with one defect. The signals are reversed in the time domain to regenerate at each received place. In From the above image, we can identify the displacement interference near the area of the defect location, which shows that the time reversed method can identify the two defects inside concrete structures. Furthermore, more work should be performed in experiments to verify the robustness of this method.DI curve was linear to the cross-section loss along the interface of steel and concrete.The defect depths along the interface of steel and concrete can be evaluated by an L  ultrasonic guided wave actuated at one end of the steel based on time reversed method. The After detecting the location of the defect, another time reversed method detecting system was performed at a certain “defected” boundary surface of the reinforced concrete samples to continue the time reversed method damage image. By comparing the intact cross-section and the defect cross-section, the time-reversal waves can locate the damage inside the reinforced concrete samples by focusing on the area of the damage.In the discussion part, the concrete without steel is simulated to apply the time reversed method to identify the two signal sources. The results showed that the two signal sources inside the concrete can also be localized using UT based on time reversed method. This work can help the engineer detect multiple damages in reinforced concrete structures if the damages are not very far from each other.Monitoring reinforced concrete structures with ultrasonic waves based on time reversed method both from the steel ends and the concrete surface can evaluate the defect severity and can identify the location and the boundary of the inside defects. Due to the different boundary conditions of the detecting samples, the incident waves are carefully selected by the material parameters and the geometry of the samples. The proposed time reversed method detecting systems are adapted to perform the experiments. From the overall results and analyses, the following conclusions are made:


Nevus comedonicus is a rare developmental abnormality of the infundibulum of the hair follicle.We report here an unusual case of bilateral extensive nevus comedonicus of the eyelids complicated by bilateral ptosis and ectropion of the lower eyelids. Blepharoplasty was performed on both upper eyelids. Histopathological findings on skin biopsy typically show large, grouped, dilated follicular ostia filled with keratin.This case is unusual as regards the late-onset (lesions first appeared at age 35) and location of the nevus comedonicus on both eyelids. The disorder is usually an isolated manifestation, but has been associated with skeletal defects, abnormalities of the central nervous system and ocular lesions to constitute nevus comedonicus syndrome.2A 69-year-old African Caribbean woman presented with a complaint of bilateral upper visual field defect in the setting of long-standing peri-orbital cutaneous lesions. She had a history of kidney graft secondary to terminal polycystic kidney disease. She had no history of trauma or periocular inflammation to the eye or the head. The cutaneous lesions appeared around the age of 35 with extensive progression. They were keratotic and hyperpigmented with multiple papules. Ophthalmologic examination showed bilateral ptosis and ectropion of the lower eyelids with bilateral punctuated superficial keratitis and inferior corneal pannus . Pupils 3Nevus comedonicus is one of the rarest forms of epidermal nevus. It is commonly present at birth or appears during childhood. It is usually asymptomatic and unilateral with a predilection for the face, neck, chest.4This case is unusual as regards the late-onset and location of the nevus comedonicus on both eyelids. Comedonicus nevus are benign lesions limited to the superficial dermis and require surgery for cosmetic and functional improvement, if there are upper visual field defect or corneal exposure.I certify receiving and having archived the written consentement of Mme X, who has Nevus comedonicus palpebral about potential medical press publication of her clinical observation. This report does not contain any personal identifying information.All authors attest that they meet the current ICMJE criteria for Authorship.We have no financial interest or conflicting relationship concerning the subject of this paper.The following authors have no financial disclosures: Adam T, Hage R, Ahomadegbe C, Molinié V, Baubion E, Merle H.


We are writing to reply to the comment by Pouwels et al., 2019 about our recent study  on antibiotic use and antibiotic resistance. We thank Pouwels and colleagues for their thoughtful critique and appreciate their concern for the role that analyses like ours could play in public health policy . MoreoveIn our original analysis, we evaluated several questions about the relationships between antibiotic use and resistance. First, we described the distribution of antibiotic use across the population and showed that it is uneven, as some individuals had no antibiotic pharmacy claims and others had many. Second, we characterized the landscape of correlations between antibiotic use and resistance for antibiotics and many pathogens. Third, we investigated whether first or repeat antibiotic use is more strongly associated with resistance at the population level. To do so, we partitioned a person's number of antibiotic pharmacy claims in a year into the sum of ‘first use’ – zero if the person had no claims for that antibiotic, one if they had at least one claim – and ‘repeat use’, the number of claims beyond the first. Previous reports speculated that repeat use would have a greater effect on population-level antibiotic resistance than first use, in other words, that ‘intensive’ use of antibiotics in a few people is more important for resistance than ‘extensive’ use across many people. In our analysis, we found no evidence that repeat use was more strongly associated with resistance. If true, these results imply that antibiotic stewardship should not necessarily focus their attention on a few, high-consuming antibiotic users.First, does reverse causality  dominate over forward causality  in associations between antibiotic use and resistance, as Second, does reverse causality influence repeat use more than it influences first use? We again disagree with Third, how does analyzing overall antibiotic, rather than the use of particular antibiotic classes, affect the interpretation of the resulting models? We disagree with the interpretation of this kind of analysis in With respect to first use, We similarly question the logic that models of overall repeat use rather than repeat use of particular antibiotic classes should be less susceptible to reverse causality. In contrast to the above, we heartily agree with the final point of


Penicillium isolates, 6 Aspergillus, 2 Trichoderma, and 1 isolate of Alternaria. First, we have identified two dominant isolates, Aspergillus fumigatus and Penicillium brevicompactum, and characterized their destructive properties according to the radial growth rate, antagonistic activity towards bacterial habitants of concrete, and production of organic acids. Then, we have demonstrated that five tested brands of high-strength concrete differ in bioreceptivity. The alterations in concrete resistances to compression and flexure after fungal attack were recorded at the trend level, mainly due to a short exposure time of concrete to fungal destructors in tests recommended by national Russian standard. Finally, using scanning electron microscopy we have shown that colonization of concrete by the dominant fungi includes their penetration into the thickness of concrete and germination in cracks. Elementary analysis revealed the decrease of calcium content on about 41% after fungal growth on the concrete in liquid phase and on 32% by superficial growth in comparison with the samples without fungal treatment.Concrete resistance to the destructive action of microorganisms is considered as a measure of its durability and is increasingly being raised as an important issue. We focused our study on the biodeterioration of concrete specimens widely used as a building material of urban houses by micromycetes isolated from the inner wall surface of the former military hospital in Kazan city, Tatarstan, Russia. Fungal community consists of 9 Biogenic deterioration of the concrete traditionally referred to microorganisms. The causes of building material biodeterioration are three main processes: mechanical, assimilative , and dissimilative  . The actof acids . Biodeteof acids . We focu Desulfotomaculum) in destruction of houses is minimal. The basic destructors in this area are micromycetes synthesizing broad spectrum of organic acids which can be extremely aggressive to concrete [Many buildings are believed to have been damaged to varying degrees by microbiologically induced destruction of concrete. Until today, there is no clear understanding of the extent and severity of the damage, the operative mechanism, and effective remedial techniques for the microbial attack to concrete structures . There iconcrete . MoreoveOur study is aimed at isolation and identification of filamentous fungi growing on the concrete walls of old buildings in Kazan city  and characterization of their destructive properties based on the measurement of growth rate and acid production, for the future assessment of deterioration level of fine-grained concrete induced by them. Applying an integrated approach combining methods of microbiology with standard methods for determining the strength of building structures, we justified the connection between the decrease of concrete strength and the level of fungal metabolic activity whose main markers were production of organic acids, radial growth rate, and antagonistic activity. Aspergillus and Penicillium were used to study their destructive properties. For the cultivation of micromycetes, a liquid and agarized Czapek-Dox medium was used (g/l): NaNO3 - 2.0; KH2PO4 - 1.0; MgSO4×7 H2O-0.5; KCl - 0.5; FeSO4 - 0.01; sucrose - 30.0; H2O - 1000 ml. Microscopic identification of dominant fungi was supplemented by Sanger sequencing of ITS  regions of the isolates using standard primers ITS1 and ITS 4 [The microscopic fungi were isolated from the inner wall surface of the former military hospital in Kazan city . The surface of the concrete wall with visible growth of micromycetes at 10 different sites was treated with a sterile cotton swab, which was then placed in a tube with 5 ml of sterile water. From there, 10 samples of 100 ml (in triplicates) were applied to a solid Czapek-Dox medium in Petri dishes, which were incubated for 5 days at 30°C. The morphology of colonies was analyzed microscopically. Total number of isolates was 18. The dominant fungi of the generand ITS 4 . Variabl2. The prepared sterile beams were placed in containers presterilized with 70% ethanol (5/ml) were added  and concretes of classes B45, B60, and B70 the ratio of sand (fraction 0.5-0.25 mm corresponding to Russian state standard GOST 8736-93) and cement was three to one. In the manufacture of concrete class B45, B60, and B70  based on Portland cement PC500, Melflux 2651 F superplasticizer (BASF Construction Polymers) was added in an amount of 0.5% by weight of cement . The water/cement ratio was 53/100. For universality of notation, hereinafter we use the term “cement” for all samples. The strength of concrete is specified by the marks denoted by the Latin letter “M” and by numbers from 400 to 1000, depending on the amount of cement used in a mix and indicating the compressive strength in kg/cm ethanol . Contain Figures . Controlμm particles. The elution was carried out at room temperature in a linear gradient using a system consisting of a solution of 10 mM KH2PO4 adjusted with orthophosphoric acid to pH 2.4 (eluent A) and acetonitrile (eluent B).The flow rate of the mobile phase was 1 ml/min. Peaks were identified using a UV detector at 210 nm [Cultural fluid of 18 fungal isolates growing 5 days up to the end of exponential phase on liquid Czapek-Dox medium was analyzed on the production of secreted organic acids using a high-performance liquid chromatograph Flexar . The separation of organic acids was carried out in a Brownlee Analytical C18 (150 × 4.6 mm) column packed with 3 t 210 nm . As stano)/(t - to), where ro is the radius of the colonies at the initial time to and r is the radius of the colonies at the time t.The rapid growth rate of fungi is connected with the production of organic acids as primary metabolites. To found the most active fungal isolates, the determination of micromycete radial growth rate (RGR) was performed. The colony diameter of isolates on agar medium was measured each 24 h in eight mutually perpendicular directions; arithmetic mean was taken at each time-point. The RGR was calculated according to the formula: RGR = . Compressive and flexural strengths were tested before and after exposure to growing mycromycetes as described earlier .Concrete samples were washed, fixed by glutaraldehyde , dehydrated with ethanol and dried at room temperature. Before microscopy samples were coated with gold/palladium. The determination of the element composition and visualization of concrete surface structure were carried out using scanning electron microscopy . Surface morphology was analyzed at an accelerating voltage of 5 keV. Elemental analysis was carried out at an accelerating voltage of 20 keV and a working interval of 9 mm. A set of Aztec program standards  was used.σ in it did not exceed 12%.Mathematical processing of data was carried out using standard computer program Excel 7.0. All experiments were carried out in at least three replicates. The data group was considered homogeneous if the root-mean-square deviation  Eurotiomycetes and family Trichocomaceae. Predominant genera (83%) were filamentous fungi Penicillium (9 isolates) and Aspergillus (6 isolates). Micromycetes of the genera Alternaria (1 isolate) and Trichoderma (2 isolates) were found to be minor representatives.We have isolated 18 micromycetes from the inner walls of the old hospital building in Kazan city and found that fungal communities represented the class Alternaria and Trichoderma, are able to synthesize oxalic acid. Malic acid was found in cultural fluid of 14 micromycetes, acetic acid was synthesized by 10 isolates, citric—by 9, lactic—by 5, and tartaric acid—by two isolates  and five to the genus Aspergillus  ( Aspergillus A2 (77.74 mg/l). Despite the fact that this A2 isolate had the highest concentration of citric acid in the culture liquid, the percentage ratio of citric acid among all other produced organic acids (their joint content was taken for 100%) was only 12.5%. The maximum percentage ratio of citric acid  was detected for Penicillium P4. Based on this data and the measured values of RGR ( A. fumigatus A2 and P. brevicompactum P4 for the treatment of concrete samples. ITS region sequences are represented in Supplementary.Of the nine isolates capable of synthesizing citric acid four isolates belonged to the genus and A6) . The maxs of RGR  we selecth day of the experiment, growth of A. fumigatus A2 and P. brevicompactum P4 on the all concrete samples was appeared  recommended treating the samples by fungi during 28 days. After 28 days of contact with the strain A. fumigatus A2 and P. brevicompactum P4 in containers partially filled with medium, the values of concrete samples stability were determined. As it can be seen from f) and to compression (Rc) after contact with the growing strains decreased by no more than 1% indicating that there are low changes in the concrete specimens strength. The minimal changes were also observed when the samples were incubated in medium without inoculation ( P. brevicompactum P4 into the thickness of concrete and germination in cracks was established using scanning microscopy ( A. fumigatus A2 (data not shown). It should be noted that fungal growth on the surface of concretes which were completely immersed to a depth of 5 cm in the culture medium  to test alteration of concrete strength. According to our data, the species isolated from the old building walls differ from recommended ones. This means that the biodeteriogen microorganisms are special for each particular building which they inhabit. Micromycetes isolated in this study mainly belong to the genera Aspergillus and Penicillium. The species identification was carried out for two more aggressive isolates, A. fumigatus A2 and P. brevicompactum P4, which were selected for analysis of their biodeteriogen activity towards concrete samples because of high level of primary metabolites synthesis , as well as because of high growth rate which provides the advantage in settling ecological niches compared to slow-growing microorganisms.The reason for the concrete destruction of city buildings is mainly the incorrect operating conditions, rather than the spontaneous effects of atmospheric precipitation. The lack of room ventilation, high humidity, a large crowd of people, and, finally, a long time of operation all cause a slow, but permanent destruction of concrete structures used for internal floors of residential buildings. That is why our research is aimed at identifying microorganisms that destroy concrete in the real operating conditions of buildings. It was important to determine how different types of concrete used in construction are susceptible to biodeterioration and how standard tests to determine it reflect the real situation. To date, there are more than 200 different methods to test biostability of building materials. Along with international standards, there are national standards for individual countries . GOST 9.048-89 recommends the application of 8 different fungi , Monascus, Nigrospora, Aureobasidium, and Cladosporium [ A. fumigatus, A. melleus, A. niger, A. versicolor, Cladosporium herbarum, Purpureocillium lilacinum, and P.brevicompactum [A. fumigatus and P. brevicompactum) which we have also isolated from the walls of old hospital in Kazan. So, it could be concluded that biodeteriogen fungi isolated from concrete walls of buildings completely differ from isolates from painted surfaces.The main fungal genera detected on painted buildings over the 42-week period wereosporium . A list ompactum . At thisAdverse effects of geoactive fungi include biodeterioration of natural and synthetic materials, rock and mineral-based building materials , cultural heritage, metals, alloys, and related substances . There a P. brevicompactum P4 growth on the concrete, which was higher in case of growth in liquid phase compared to the superficial growth  to surface contacted with air (36%). The alterations of the compressive and flexural strengths of concrete specimens depending on concrete brands were detected along with decrease of calcium content. The stability of concrete samples exposed to growing