Western blot analysis showed that edonerpic maleate reduced the cleavage of collapsing response mediator protein 2 (CRMP2), but increased the expression of postsynaptic protein Arc. By using gene overexpression and silencing technologies, CRMP2 was overexpressed and Arc was knockdown in cortical neurons. The results showed that the effect of edonerpic maleate on NMDA receptor expression was mediated by CRMP2, whereas the edonerpic maleate-induced AMPA receptor regulation was dependent on Arc activation. In in vivo TBI model, 30 mg/kg edonerpic maleate alleviated the TBI-induced brain edema, neuronal loss, and microglial activation, with no effect on locomotor function at 24 h. However, edonerpic maleate improves long-term neurological function after TBI. Furthermore, edonerpic maleate inhibited CRMP2 cleavage but increased Arc activation in vivo. In summary, our results identify edonerpic maleate as a clinically potent small compound with which to attenuate TBI-related brain damage through regulating GluRs signaling.Dysfunction of ionotropic glutamate receptors (iGluRs) is a key molecular mechanism of excitotoxic neuronal injury following traumatic brain injury (TBI). Edonerpic maleate is a low molecular-weight compound that was screened as a candidate neuroprotective agent. In this study, we investigated its effects on TBI and GluRs signaling. Traumatic neuronal injury (TNI) induced by scratch followed by glutamate treatment was performed to mimic TBI in vitro. Edonerpic maleate at 1 and 10 μM exerted protective activity when it was added within 2 h following injury. The protective activities were also confirmed by the reduction of lipid peroxidation and oxidative stress. In addition, edonerpic maleate inhibited the expression of surface NR2B, total GluR1, and surface GluR1, and mitigated the intracellular Ca Traumatic brain injury (TBI) is defined as an injury of brain pathology or brain function induced by external forces, such as fall, assault, or motor vehicle crash. It may lead to short- or long-term neurological dysfunction and remains a major public health problem worldwide . In the Glutamate is the major excitatory neurotransmitter in the brain, and excessive release of glutamate has been found in many acute and chronic neurological diseases. In severe TBI patients, the microdialysis results showed that the rise in extracellular glutamate was detected from 24 h to 4 days after injury, which is directly proportional to mortality  and coulEdonerpic maleate  ethoxy] propyl-3 -azetidinol maleate) is a newly synthesized low molecular-weight compound that was screened as a candidate neuroprotective agent with promoting effects on axonal regeneration . EdonerpIn the present study, we determined the effects of edonerpic maleate in an in vitro model established by glutamate treatment following scratch in primary cultured neurons, as well as in an in vivo model induced by CCI in rats. Considering the role of CRMP2 in NMDA receptor-mediated excitotoxicity after TBI , we alsoTo mimic neuronal injury following TBI in vitro, cultured cortical neurons were injured by scratch and exposed to 100 μM glutamate. Edonerpic maleate at 1 and 10 μM, but not 0.1 μM, significantly reduced LDH release after TNI and glutamate treatment Fig. . In cong2+ and lasted for 30 min after injury. Edonerpic maleate markedly inhibited Ca2+ increase, as evidenced by decreased peak amplitude and value of the area under the curve (AUC) for the Ca2+ measurement  once a day for 3 weeks before CCI. Brain edema was determined by measuring brain water content, and only 30 mg/kg edonerpic maleate reduced brain edema after TBI Fig. . FunctioDue to the negative results in locomotor function at 24 h following TBI, we further investigated the effect of edonerpic maleate (30 mg/kg) on neurological function using mNSS Fig. . As expe2+ homeostasis; (c) edonerpic maleate decreases CRMP2 cleavage to reduce surface NR2B expression; (d) edonerpic maleate increases Arc expression to inhibit GluR1 expression; (e) edonerpic maleate attenuates brain damage and preserves long-term neurological function after TBI; and (f) edonerpic maleate regulates CRMP2 and Arc in vivo.In this study, we identified edonerpic maleate, a newly synthesized compound for Alzheimer’s disease (AD) treatment, as a neuroprotective agent that protects against TBI both in vitro and in vivo. We found that (a) edonerpic maleate inhibits oxidative stress and neurotoxicity following neuronal trauma; (b) edonerpic maleate regulates glutamate receptors expression and intracellular CaP > 0.05). Here, the locomotor function, as evidenced by locomotor speed and cadence, was measured at an early state, which is largely related to the primary injury itself and the function of the perilesional remaining motor cortex [In CCI-injured animals, we observed a significant reduction in locomotor speed, and the reduced cadence was also found in the TBI group. However, treatment with edonerpic maleate, even at the high dose (30 mg/kg), which has been demonstrated to be protective in experimental AD models, had no effect on locomotor function  [2+ imaging that the increased intracellular Ca2+ signaling was attenuated by edonerpic maleate. The increased intracellular Ca2+ concentration following glutamate over-release is called Ca2+ overload, which is considered to be a key mechanism for delayed neuronal cell death. Ca2+ overload disrupts mitochondrial ATP generation and activates proteases and kinases, leading to transcription of proapoptotic genes and activation of detrimental cascades [2+ imaging experiments. We found that edonerpic maleate was also effective in alleviating intracellular Ca2+ concentration after exposure to NMDA or AMPA. All these data indicate that the protective effects of edonerpic maleate in our in vitro model are partially mediated by its dynamic regulation of glutamate receptor subunits and followed intracellular Ca2+ metabolism.Glutamate-induced neurotoxicity is mainly mediated by activation of GluRs, especially iGluRs, and following alterations in intracellular Camostasis . Targetimostasis , 22. Howmostasis , 24. Foreceptor) . The effcascades . To furt2+ influx following NMDA exposure. NR2B subunits of NMDA receptors appeared to be the key subunit implicated in excitotoxicity in cortical neuronal cultures [+/Ca2+ exchanger (NCX) and NMDA receptors, and TAT-CBD3, a 15-amino acid peptide from CRMP2, protects against Ca2+ dysregulation through suppression of both NMDAR and NCX activities [2+ influx and currents in cultured neurons [What are the molecular mechanisms linking edonerpic maleate and the expression of glutamate receptor subunits? We further performed a western blot to detect the expression of CRMP2, the most studied member of the CRMP family. CRMP2 was originally described from a screen for gene mutations affecting axon growth and has been shown to be involved in many neurological disorders, including neuropathic pain, PD, multiple sclerosis, and AD –29. A prcultures , 35. CRMtivities . In addi2+ influx, leading to intracellular Ca2+ overload and excitotoxicity-related neuronal cell death [2+ influx was attenuated by edonerpic maleate, indicating the involvement of AMPA receptor-associated mechanism. AMPA receptors are highly dynamic receptors formed by different combinations of four GluR receptors, GluR1-4, and their functional properties largely depend on subunits composition and receptor trafficking to and from the plasma membrane [2+ influx [2+ modulation might be one of the mechanisms underlying edonerpic maleate-induced protection against TBI.Besides NMDA receptor subunits, some AMPA receptors (CP-AMPA receptors) also mediates Call death , 38. It membrane . Arc is membrane . The elemembrane , and ourmembrane , 43. In + influx . Thus, w+ influx . Our preThere are a few limitations to the present study. First, cultured cortical neurons were used to establish the in vitro TBI model, and this can not totally mimic the in vivo situation due to the lack of glial cells and endothelial cells. It is well-known that the excitatory amino acid transporters expressed in glial cells are the key mechanism for glutamate signaling and related excitotoxicity , 46. Som2+ overload and oxidative stress. These effects were mediated by its effects on CRMP2 cleavage and Arc activation. The efficacy of edonerpic maleate in TBI patients should be evaluated in clinical trials.In summary, our present study showed that edonerpic maleate protects against TBI-related neuronal injury both in vitro and in vivo. Edonerpic maleate differently regulated the subunits of iGluRs and thereby inhibited intracellular CaAdult male Sprague-Dawley (SD) rats (weighting ~300 g) and pregnant female SD rats (E16–18) were purchased from the Animal Experimental Center of Anhui Medical University. All animal procedures were approved and supervised by the Animal Ethics Committee of Anhui Medical University (No. 2018-WX-011).l-Glutamine and plated at a density of 3 × 105 cells/cm2. Before seeding, culture vessels, consisting of 96-well plates, 1.5 cm glass slides, or 6 cm dishes were coated with PLL (50 μg/mL) at room temperature overnight. Neurons were maintained at 37 °C in a humidified 5% CO2 incubator and half of the culture medium was changed every other day. Neurons were incubated in six-well plates and scratched by a 200-μl yellow gunshot. After a scratch, 100 μM glutamate was added into the culture medium to mimic excitotoxicity following TBI.Cortical neurons were cultured from pregnant female SD rats (E16–18) using our previously described methods . BrieflyNeuronal toxicity was determined by measuring LDH release into the culture medium using a commercial kit according to the manufacturer’s protocol .Cell viability of cortical neurons was determined by Calcein AM assay using a kit according to the manufacturer’s protocol .Malonyl dialdehyde (MDA) and 4-hydroxynonenal (4-HNE), two index of lipid peroxidation, were determined using assay kits from Cell Bio labs and strictly following the manufacturer’s instruction.The levels of the inflammatory cytokines, including TNF-α and IL-1β, were measured by ELISA kits following the manufacturer’s protocols .2+ imaging was performed using the Ca2+ indicator Fura-2 AM  to measure the intracellular Ca2+ concentrations [0.Catrations . The neug for 2 min at 4 °C. Twenty percent of the supernatant was reserved as the total protein. The remaining 80% of the cell lysate was rotated with NeutrAvidin Agarose for 1 h at 4 °C. Gels were washed with wash buffer and centrifuged at 1000 × g for 1 min at 4 °C. A sample buffer containing dithiothreitol was added to the gels, and this was followed by centrifugation at 1000 × g for 2 min at 4 °C. After the addition of bromophenol blue, samples were used to perform biochemical studies and western blotting.The surface biotinylation assay was performed with the Pierce Cell Surface Isolation Kit (Thermo Scientific), according to the manufacturer’s instructions. Neurons were washed twice with ice-cold NaCl/Pi and then incubated with Sulfo-NHS-SS-Biotin solution for 30 min at 4 °C. A quenching solution was added to quench the unreacted biotin. The cell pellet was collected and then resuspended in RIPA buffer. After sonication and incubation, the cell lysate was centrifuged at 10,000 × To develop overexpression lentiviruses, cDNA of CRMP2 was subcloned into a G492 lentiviral vector (Ubi-MCS-3FLAG-CBh-gcGFP-IRES-puromycin). The cultured cortical neurons on DIV12-14 were used for transfection. To knockdown Arc expression, Si-Arc (sc-29721) and control siRNA  were purchased from Santa Cruz . The siRNA molecules were transfected using Lipofectamine RNAiMax reagent (Invitrogen) in an Opti-MEM medium according to the manufacturer’s instructions. After incubation for 48 h, culture media was changed to Neurobasal medium (NBM) containing 2% B27 supplement, and neurons were exposed to edonerpic maleate.d-lysine-coated coverslips and treated with TNI, glutamate, and/or edonerpic maleate. After being fixed with 4% paraformaldehyde, permeabilized with 0.1% Triton X-100 and washed with PBS three times, neurons were blocked by 5% bovine serum albumin (BSA). Incubation with the DMPO  and Arc  primary antibodies was performed at 4 °C overnight. After being washed by PBS with Tween-20 (PBST) three times, the samples were incubated with the secondary antibody at 37 °C for 1 h. Then, incubation with 4′, 6-diamidino-2-phenylindole (DAPI) was performed to stain the nuclei, and the images were obtained using a Leica SP5 II confocal microscope.For immunostaining, neurons were cultured in poly-The controlled cortical impact (CCI) model was performed to mimic brain damage induced by TBI in vivo. Briefly, rats were anesthetized with an intraperitoneally administered 10% chloride hydrate (3.0 mL/kg) and placed in the stereotaxic frame. A 7-mm-diameter craniotomy was performed over the right cortex midway between the lambda and the bregma. To induce injury, a pneumatic piston impactor device (100 g) with a 4.5 mm diameter and rounded tip was used to impact the brain at a depth of 2 mm (velocity 5 m/s). Then, the scalp wound was closed by standard suture material and the wound area was treated with lidocaine cream. During surgery, a warming pad with feedback temperature control ensured a sustained normal body temperature.2O = (1 − dry weight/wet weight) × 100%.Brian’s edema was determined by measuring brain water content using the standard wet and dry method. After rats were anesthetized and sacrificed by decapitation, the brains were quickly removed and separated through the inter-hemispheric fistula into left and right hemispheres. Tissue samples from injured hemispheres were weighed immediately to get wet weight. After drying in an oven for 48 h at 100 °C, the tissues were reweighed to get the dry weight. Brain water content was then calculated using the following formula: % HThe modified neurological severity score (mNSS) test was used to evaluate motor, sensory, reflex, and balance function of rats at 0, 1, 3, 7, and 14 days following TBI.The Morris Water Maze (MWM) test was used to evaluate the learning and memory function of rats. The spatial acquisition trial was performed from 14 to 18 days, and the probe trial was performed at 19 days following TBI as previously described . A circuBrain sections with 4 μm thickness and neurons on the coverslips  were treated with 0.1% Triton X-100 and then were blocked by 5% BSA. The samples were incubated with the following primary antibodies: NeuN , Iba-1 , CRMP2 , and Arc  at 4 °C overnight. After being washed by PBST three times, the samples were incubated with the secondary antibodies at 37 °C for 1 h. Then, incubation with DAPI was performed to stain the nuclei, and the images were obtained using a Leica SP5 II confocal microscope.A standard western blot assay was performed using the following primary antibodies: NR2A , NR2B , GluR1 , GluR2 , CRMP2 , Arc , and β-actin . After incubation with secondary antibodies for 1 h, the bands were visualized by using a chemiluminescent detection system. The western blot data were shown in t-test  was performed for all statistical significance. A value of p < 0.05 was considered statistically significant.Statistical analysis was performed using SPSS 16.0, a statistical software package. The data analysis was carried out by a blinded investigator, who did not know which group the samples came from. The Student’s Supplemental Material


AITallergen immunotherapyBATbasophil activation testBLGbeta‐lactoglobulinCMcow’s milkCMAcow’s milk allergyD1name of engineered antibodies due to their published, variable regionsELISAenzyme‐linked immunosorbent assayFA‐AITfood allergen immunotherapyILinterleukinISACImmuno‐Solid phase Allergy ChipOIToral immunotherapyPBMCperipheral blood mononuclear cellsPIPE cloningpolymerase incomplete primer extension cloningRTroom temperatureSDS‐PAGEsodium dodecyl sulphate‐polyacrylamide gel electrophoresisTBSTris‐buffered salineTBS‐TTBS‐TweenUHT milkultra‐high temperature processed milkTo the Editor,Cow's milk (CM) allergy (CMA) is defined as an immune‐mediated adverse response to CM proteins.,S01 Food allergen immunotherapy (FA‐AIT) applying increasing antigen doses  can contribute to improvement of CMA,S02 with variable clinical efficacy,,S03 but immunologically often resulting in decreased specific IgE levels and increased specific IgG4 levelsS04,S05. IgG4 is (a) anti‐inflammatory as it does not activate the complement system; (b) bi‐specific due to fab‐arm exchange and, thus, has less crosslinking capacity than IgE, but has (c) blocking capacity.2% to 3% of children are suffering from CMA, but many develop natural tolerance after 3‐4 years.Antibodies of different isotypes with the same variable region could be essential in molecular studies of the mechanism underlying CMA and might shed light onto the function of specific IgG4 antibodies during the acquisition of tolerance.−9 M; kon = 1.4 × 106, koff = 1.54 × 10−3)S06 specific for the major CM allergen beta‐lactoglobulin (BLG), with the constant domains of IgE or IgG4 antibodies  cloning is a cutting‐edge technique to engineer antibodies against various targets and facilitates simple exchange of the constant regions to increase the range of subtypes of antibodies.s Figure . Corrects Figure . The excs Figure , in ISACs Figure  and in Is Figure .P < .01), but no differences in the IgG4 levels were seen between the groups  and sensitised but tolerant patients (n = 8). Allergic children had significantly higher levels of IgE  and IL‐13  is a reliable method to evaluate functional capacities of antibodies, allowing at least an approximation to the real‐life situation of an allergic patient. When IgE‐stripped basophils from healthy donors were sensitised with D1 IgE antibodies and triggered with BLG, basophil activation levels comparable to primary basophils from milk allergic patients in other studies were achieved.P = .0402) or 100 nmol/L D1 IgG4 (P = .0029) significantly decreased the percentage of CD63+ basophils (Figure S07The blocking capacity of D1 IgG4 antibodies was investigated in an ELISA. As expected, the D1 IgG4, harbouring the same variable region, could decrease D1 IgE binding to plate‐bound BLG in a concentration‐dependent manner Figure . In accos Figure . In agreS08Whether the IgG4 antibodies could be applied as passive immunotherapy in cow milk allergic patients depends on a thorough risk‐benefit analysis, but studies in cat allergy promise that this might be possible in the future.persisting tolerance, or in primary tolerance to milk? Contrasting results about the efficacy of oral immunotherapies for CMA may be explained by differences in the methods regarding the duration of the intervention, dosages of the allergen or the composition of the milk. The PIPE‐cloned antibodies presented here may add to the comparability of such studies between laboratories. Another application of the D1 antibodies may be in studies on the effect of milk processing on immune responses. Food processing can massively influence the structure of the allergens and therefore alter their allergenicity.S09,S10 Especially during heat processing, important BLG epitopes are lost, but IgE binding is significantly increased after pasteurisation.S11 Overall, the generated antibodies may shed light on milk allergenicity, bring critical insight into the development of CMA and help developing prevention strategies.Our antibodies have so far proven valuable not only for the quantification of BLG and BLG‐specific human serum antibodies, but also for functional studies. With these tools, some questions could be addressed in the future: Are IgG4 antibodies involved in the establishment of EJJ is founder and shareholder of Biomedical Int. R+D GmbH, Vienna, Austria, and business partner of Bencard Allergie GmbH, Germany as well as AllergyTherapeutics Ltd., UK, but has no COI in relation to the presented work. EJJ also holds patents in lipocalins including BLG for allergen immunotherapy. SNK is founder and shareholder of Epsilogen Ltd. and holds patents on IgE antibodies for cancer therapy. AF is conducting research supported by Danone SA and Hipp GmbH. He has been in the advisory boards of Abbott SA and Hipp GmbH over the last two years. The other authors have no potential conflicts of interest to disclose.Figure S1Click here for additional data file.Figure S2Click here for additional data file.Figure S3Click here for additional data file.Supplementary MaterialClick here for additional data file.


Sulfate attack is one of the crucial causes for the structural performance degradation of reinforced concrete infrastructures. Herein, a comprehensive multiphase mesoscopic numerical model is proposed to systematically study the chemical reaction-diffusion-mechanical mechanism of concrete under sulfate attack. Unlike existing models, the leaching of solid-phase calcium and the dissolution of solid-phase aluminate are modeled simultaneously in the developed model by introducing dissolution equilibrium equations. Additionally, a calibrated time-dependent model of sulfate concentration is suggested as the boundary condition. The reliability of the proposed model is verified by the third-party experiments from multiple perspectives. Further investigations reveal that the sulfate attack ability is underestimated if the solid-phase calcium leaching is ignored, and the concrete expansion rate is overestimated if the dissolution of solid-phase aluminate is not modeled in the simulation. More importantly, the sulfate attack ability and the concrete expansion rate is overestimated if the time-dependent boundary of sulfate concentration is not taken into consideration. Besides, the sulfate ion diffusion trajectories validate the promoting effect of interface transition zone on the sulfate ion diffusion. The research of this paper provides a theoretical support for the durability design of concrete under sulfate attack. Sulfate attack is one of the main factors leading to the performance deterioration of reinforced concrete (RC) structures subjected to sulfate environment ,2. The sCS¯H2) . Gypsum AS¯3H32) . The expAS¯3H32) ,6. HowevAS¯3H32) , which pAS¯3H32) ,9,10. ItThe diffusion-reaction process of sulfate ions in concrete has been widely investigated by experiments and numerical simulations ,11,12 ovCH) and the decalcification of calcium silicate hydrates (C-S-H) supplement the calcium ion consumed by the chemical reaction , respectively.The sulfate ion in the environment diffuses into the concrete and reacts with the calcium ion in the pore solution of concrete to form CS¯H2 ,17, as iCS¯H2 ,38, whicC-S-H) , 3), and 3), respectively.Calcium ion in concrete pore solution consumed by the chemical reaction between sulfate ion and calcium ion can be supplemented by the dissolution of calcium hydroxide (CH) and decalcification of hydrated calcium silicate (C-S-H) ,39. ThisC-S-H) ,39. The C-S-H) . Before C-S-H) , as showC-S-H) . The leaC-S-H) . The larC-S-H) . Similar2/s).Moreover, to reflect the consumption of calcium ion in pore solution and the leaching of solid-phase calcium, the chemical reaction kinetic equation of calcium ion in pore solution can be written by Equation (4).3AC), tetra calcium aluminate (4AH13C), and monosulfate  with q is the stoichiometric weighted coefficient with 3).Similar to the previous works ,40, to sessed as :(9)∂Cgpy3), 2/s), 3), and 3 s)], respectively. Since the chemical reaction process occurs in the concrete pore solution, the chemical reaction between gypsum and aluminate can also be described by a reaction-diffusion-dissolution process, written as Equation (10) ,47,48:(13 s)], and 3).Similar to the leaching process of solid-phase calcium, the dissolution process of solid-phase aluminate can be described by Equation (11) ,35:(11)∂k and m are the empirical parameters, The ettringite produced by sulfate attack has expansibility, which will produce expansion pressure on the concrete pore wall. Once the expansion pressure exceeds the limit strength of concrete, microcracks appear and the mechanical performance of concrete deteriorates ,47,49. Te attack , which cfined as ,15:(13)εe of 0~1 .3/mol), 3), 3/mol), and 3/mol), respectively. The detailed calculation process can refer to the literature [It is assumed that the expansion caused by the formation of gypsum is negligible . The chaterature .The expansion rate of concrete can be calculated by the linear strain obtained at each point, which can be written by Equation (23) ,44.(15)In the process of sulfate attack, the gypsum further reacts with the aluminate to form ettringite. On the one hand, the formation of ettringite makes the porosity of concrete decreasing and the diffusion channel of sulfate ion narrow, and thus inhibits the diffusion of sulfate ion . On the w/c is a water-cement ratio. When w/c is less than 0.5, The effects of the porosity and microcrack on the diffusivity of sulfate ion are considered simultaneously in the calculation of the effective diffusion coefficient of sulfate ion. Based on the migration and porosity test results obtained by Zhang et al. , the chas’ model :(17)φ0=vessed as ,59: (18)The porosity of concrete after sulfate attack is the difference between the initial porosity and the porosity reduced by chemical reaction, which can be expressed as Equation (19).When the crack density is sparse, the mean-field can be used to study the effect of crack on sulfate ion diffusion. The diffusion coefficient can be modified by the crack density . Howeverbe 0.182 . Below tbe 0.712 .Many boundary sulfate ion concentrations are collected from experiments ,33,57 to3), 3), and Through regression analysis, the boundary sulfate ion concentration can be expressed by an exponential function, as follows: In this paper, concrete is regarded as a three-phase composite material composed of aggregate, mortar, and interface transition zone (ITZ) ,63, as s2/s), 2/s) and Moreover, due to the wall effect of aggregate and the insufficient hydration of cement , the porAdditionally, compared with ITZ and mortar, the diffusion coefficient of sulfate ion in aggregate is two orders of magnitude smaller ,71. Ther3, which is the same as that in Reference [C-S-H) and calcium hydroxide (CH) are calculated according to the method of Wan et al. [To verify the reliability of the proposed model, the sulfate attack experimental results by Xie et al.  are compn et al. . The parFurthermore, the sulfate attack model either with constant boundary sulfate ion concentration or with time-dependent boundary sulfate ion concentration is calculated for comparison. The simulation results are plotted by the red dotted curves and the blue solid curves in Furthermore, the reliability of the concrete expansion rate calculated by the numerical simulation can be verified by the experimental results of Rozière et al. . Rozière’s model is higher than that of our model and the experiment results. While in the later stage of sulfate attack, for which the ingress time is higher than 375 days, the concrete expansion rate calculated by Qin’s model is lower than that of our model and the experiment results. This can be attributed to the initial concentration of aluminate in pore solution being the total concentration of aluminate in concrete in Qin’s model, without considering the dissolution of solid-phase aluminate. Specifically, according to Equation (10), the high initial aluminate concentration leads to a high formation rate of ettringite in the early stage of sulfate attack, resulting in the calculated concrete expansion rate higher than the experimental concrete expansion rate. Moreover, with the increase of ingress time, the concentration of aluminate decreases gradually, and the consumption of aluminate cannot be replenished, correspondingly resulting in a decrease of ettringite formation rate. Moreover, the correlation coefficient between numerical simulation and experimental data is 0.98, which indicates that the numerical simulation results are in good agreement with the experimental results.The concrete expansion rate of specimen calculated by ourselves, by Qin et al., and measured by Rozière et al. are shown in w/c = 0.5 and aggregate volume fraction of 62.4% at three different ingress times  is calculated, as shown in The spatial distribution of sulfate ion concentration of concrete samples with Furthermore, due to the different sulfate ion diffusion characteristics of different components in concrete, the random aggregates in concrete leads to the non-uniformity distribution of sulfate ion concentration at the same ingress depth. Therefore, the ingress front line of sulfate ion concentration of the multi-phase mesoscopic model is curvilinear and discontinuous, as shown in To further reveal the diffusion mechanism of sulfate ion in the multiphase mesostructure of concrete, the diffusion trajectories of sulfate ions is demonstrated in The distributions of calcium ion concentration in concrete pore solution, considering the leaching of solid-phase calcium, are shown in For comparison, the concentration distribution of sulfate ion in concrete without considering the chemical reaction between sulfate ion and calcium ion in pore solution is shown by the black square scatters in 3), as shown by the black square scatters in In addition, before sulfate attack, the solid-phase calcium in the concrete is uniformly distributed , as shown by the black triangle solid line in Additionally, before sulfate attack, the total aluminate concentration in concrete is uniformly distributed , and increases gradually in the later stage of sulfate ingress , as the blue square solid curve in 3 [To investigate the influence of time-dependent boundary sulfate ion concentration on sulfate attack, the processes of sulfate attack in concrete with constant boundary condition and time-dependent boundary condition are numerically simulated for comparison, as shown in 3  in the a3 .Furthermore, the expansion rates of concrete with different boundary conditions have also been investigated as well. The expansion rate of concrete with constant boundary condition is higher than that with time-dependent boundary condition, but their difference gradually decreases with the increase of ingress time, as depicted in It is worth mentioning that the proposed numerical model of sulfate attack on concrete is applicable to ordinary concrete. Therefore, the numerical model may not be suitable for concrete with other types of concrete. This is because the mineral composition, pore structure, and mechanical properties of different types of concrete are different, which leads to the inconsistency of sulfate ion diffusion coefficient and chemical reaction caused by sulfate attack. Our findings reveal previously ignored fundamental aspects of the sulfate attack mechanism and provide insights for the durability prediction of RC structures. In the further study, relevant experimental research should be carried out to further verify and optimize the proposed model. Besides, the coupling effect of chloride and sulfate attack concrete.(1)With the increase of sulfate ingress time, the calcium ion and the solid-phase calcium near the sulfate ingress surface are completely consumed, which promote the diffusion of sulfate ion.(2)The dissolution of solid-phase aluminate has little influence on the distribution of sulfate ion concentration. However, the concrete expansion rate is overestimated if the dissolution of solid-phase aluminate is not modeled in the simulation.(3)For short-term material performance assessment, the sulfate attack ability and the concrete expansion rate are overestimated if the time-dependent boundary of sulfate concentration is not taken into consideration.(4)The sulfate ion in the mortar zone tends to diffuse into the ITZ, rather than directly diffuses in the mortar zone, indicating that ITZ is a fast channel for sulfate ion diffusion.In the present paper, a comprehensive multiphase mesoscopic model is proposed to fully reveal the chemical reaction-diffusion-mechanical mechanism of concrete under sulfate attack. Based on a systematic study, the following conclusions can be drawn:


The macroscopic physical and mechanical parameters, such as compressive strength, tensile strength, mass change and ultrasonic wave velocity, were measured. The damage mechanism of corrosion products and microstructures was analyzed using microscopic approaches including scanning electron microscopy (SEM), X-ray diffraction (XRD), etc. Linear correlation was carried out on the abovementioned physical parameters, and the results revealed that, during corrosion, the correlation between compressive and tensile strength and mass (excluding Na2SO4 solution) is positive (mostly highly correlated), while that with wave velocity is poor (mostly moderately correlated).This work explored the correlation among the physical and mechanical parameters of concrete in marine environments during corrosion. Concrete materials with varied water–cement ratios ( The three ions relatively abound in the sea areas near Dalian, Tianjin, Qingdao, and Xiamen; the sulfate ions and magnesium ions are rich in Lianyungang; while the sulfate ions and magnesium ions are the least observed in seawater near Beilun. The corrosion pressure of marine materials with high content of harmful ions is relatively high.Study of the corrosion of concrete in the marine environment has always been a topic of focus ,2,3,4,5.2SO4) and sodium chloride (NaCl); by contrast, serious deterioration was found in samples treated with a compound solution of magnesium sulfate (MgSO4) and sodium chloride (NaCl). Niu et al. [2SO4 solution, MgSO4 solution and a compound solution of Na2SO4 and NaCl, and observed that deterioration in the MgSO4 solution was worse than that in other sulfate solutions. Jin et al. [−, SO42−, and Mg2+, in seawater is critical for chemical corrosion of and damage to concrete materials, and various ions can interact with each other to promote or inhibit corrosion [The scholarly literature is rich in studies on the physical and mechanical properties of concrete materials in marine environments, with some studies regarding the damage evolution of concrete ,18,19,20u et al.  elucidatn et al.  comparedorrosion ,25,26,27There exist certain correlations among the physical and mechanical parameters of concrete in marine environments subjected to corrosion, which are often universally related, interdependent and mutually constrained. However, correlation analysis on the physical parameters of concrete in a corrosion environment is rare. Harbulakova et al.  investigThis paper studied multi-salt corrosion of concrete samples (both ordinary concrete and high-strength concrete) in simulated seawater. The samples’ physical and mechanical properties were analyzed based on tests of compressive and tensile strength, mass loss and ultrasonic wave velocity during corrosion; the roles played by corrosion solutions in the samples’ microscopic damage mechanisms were compared by measuring their microscopic composition. The principal objective of this paper was to analyze the internal correlation of each physical parameter of concrete in a corrosive environment through correlation analysis of strength, mass and wave velocity changes, and to reveal the internal relationship. The results provide a new way to characterize the damage to concrete materials in corrosive environments through the correlation of various physical and mechanical parameters.2SO4, MgSO4, and NaCl.Portland cement categorized as P·O 42.5 was utilized; its chemical composition is shown in w/c = 0.33) and ordinary concrete (w/c = 0.50). They also vary in size: the former is a cube (100 mm × 100 mm × 100 mm) for compressive strength testing and the latter a cylinder (100 mm in diameter and 50 mm in thickness) for tensile strength testing. The casting samples were demolded after 24 h natural curing. Afterwards, the samples were soaked in tap water for curing for 28 days, and then immersed in solutions for immersion corrosion testing to simulate the actual marine environment. To ensure consistency of solution concentration, plastic film was used to cover the immersion box, thus preventing moisture volatilization, and the solution was refreshed every other month.The concrete samples employed were high-strength concrete (4 + 10% NaCl solution (MC), 5% MgSO4 solution (MS), 5% Na2SO4 solution (SS) and clear water . Their concentrations are shown in The four corrosion solutions used were as follows: 5% MgSOThe immersion corrosion test lasted for 20 months, and samples were taken every month for the first year, followed by the 15th and 20th months, to test physical and mechanical parameters including compressive strength, tensile strength, mass and ultrasonic wave velocity. In addition, microscopic corrosion composition testing was conducted in the 10th month.The experiment in this paper employed a WAW-2000 model computer-controlled electro-hydraulic servo universal testing machine  with an accuracy level of 0.5. Displacement loading rates of 0.6 mm/min and 0.06 mm/min were used for the compressive strength and tensile strength tests, respectively. Three samples were randomly picked for compressive and tensile strength testing before the experiment, obtaining one group of three values each time. The median was taken as a reference, and the range was considered reasonable if the difference between the maximum, minimum and median was within 15% of the median; the average of the three measurements was taken as the strength value. The tensile strength testing method is shown in The same three samples were used for mass and ultrasonic velocity testing, and the average was obtained. An electronic balance (accuracy: 0.01 g) was utilized for mass testing. The samples were dried with a towel and placed in a drying oven at 50 °C for 2 h before the test.Ultrasonic wave velocity testing was carried out with a ZBL-U5200 Ultrasonic Detector . Its working parameters were as follows: frequency range of 1~250 kHz, sampling period of 0.4 μs, sampling length of 1024 points, acoustic time accuracy of 0.025 μs, and emission voltage of 500 V. The ultrasound opposite testing method was employed to reveal the transit time with a range of 100 mm. Three points evenly distributed on the diagonal of the surface were measured, and the average of the obtained values was used as the ultrasonic wave velocity; see The micromorphology of corrosion products was observed with a Hitachi SU70 thermal field emission scanning electron microscope , and chemical composition was analyzed using an energy dispersive spectrometer . Before testing, the corroded samples were dried and vacuum sprayed with gold a, thus eθ recording range of 5–40°, step size of 0.02°, scanning time of 0.1 s/step, and CuK α-ray wavelength of λ = 0.15406 nm. For XRD detection, samples soaked for the selected period were taken out of the corrosion solution and dehydrated with anhydrous ethanol for 48 h, and then placed into a 40 °C vacuum drying oven for 48 h, followed by grinding into powder with a ceramic mortar. Finally, the powder was passed through a 80 μm sieve and tested with X-ray diffraction (The corroded samples were X-ray diffraction (XRD) tested using a Bruker Axs D8 Advance X-ray diffractometer  with operating parameters of 40 kV, 40 mA, 2fraction b.w/c of 0.33 and 0.5 in the compound solution of magnesium sulfate and sodium chloride (MC), “3MS” and “5MS” samples with a w/c of 0.33 and 0.5 in the magnesium sulfate solution (MS), “3SS” and “5SS” samples with a w/c of 0.33 and 0.5 in the sodium sulfate solution (SS), and “3CW” and “5CW” the samples with a w/c of 0.33 and 0.5 in clear water .In the below Figures, “3MC” and “5MC” represent concrete samples with a w/c climbed the most during the increase stage, which is more obvious than that of the sample with with high w/c.The compressive and tensile strength of the high-strength and ordinary concrete samples soaked in the four corrosive solutions is shown in Compared with CW, in addition to the increase in the strength of the concrete in the first stage due to the continuous hydration, the ions in the corrosive solutions reacted with the solution infusing the pores of the material, and the generated product filled the interior of the pores, which further increased the strength of the material. This cannot be ignored. The decline in strength in the corrosive solutions was associated with material deterioration caused by reactions between corrosive ions and this internal material, which then expanded and destroyed the internal structure.Compared with samples in other corrosive solutions, samples in MC during the late corrosion stage saw a more significant decline in compressive strength than tensile strength. The compressive strength in MC drops the most, while the tensile strength in all corrosive solutions shared basically the same descending trend.w/c in the four solutions during corrosion is shown in w/c was relatively higher than that of those with a small w/c, which is driven by higher internal porosity and more pore space, leading to easier entry by external corrosive ions.The mass of samples with different The ultrasonic wave velocity of the samples is shown in After samples were immersed in solutions for 10 months and subjected to complete compressive strength testing, several small fragments were taken from them and used for micromorphology observation using a scanning electron microscope (SEM) and for chemical composition detection using an energy dispersive spectrometer (EDS). The micromorphology is shown in 2 could be found inside the concrete, along with small amounts of ettringite and gypsum, etc.Samples soaked for 10 months were ground into powder and tested with an X-ray diffractometer to detect their diffraction pattern and analyze their mineral composition, as shown in xyR) [xyR| < 0.3, the two variables are not correlated; if 0.3 ≤ |xyR| < 0.5, they are weakly correlated; if 0.5 ≤ |xyR| < 0.8, they are moderately correlated; if 0.8 ≤ |xyR|, they are highly correlated.The simplest linear correlation was employed to analyze the correlation of physical and mechanical parameters. The Pearson correlation coefficient (Rxy)  was intrw/c (high-strength concrete) were relatively more stable than those with high w/c (ordinary concrete).w/c were better than in those with low w/c. The reasons for the lower correlation could be due to the couplant: its proximity to the concrete test surface for each test, and whether coupling layer was mixed with sand or air, etc. It could also be related to individual operation problems, such as the front of the sensor not being strictly aligned. Therefore, it is unreasonable to characterize strength in a corrosive environment by merely taking the ultrasonic wave velocity.Using the correlation analysis method, a quantitative characterization relationship between the physical and mechanical parameters of the material was obtained, which further enriches the development of concrete durability theory. In engineering, the reliability of concrete structures in corrosive environments can be evaluated through appropriate physical parameters such as mass variation, which further enriches the detection methods for concrete structures in corrosive environments.The compressive strength and tensile strength displayed a significant linear correlation with corrosion. The compressive strength of samples in solutions other than SS also significantly correlated with mass. However, the linear correlation between compressive strength and ultrasonic wave velocity was weaker than the former two.The linear correlation between compressive strength and tensile strength in samples with low w/c (high-strength concrete) was relatively more stable than in those with high w/c (ordinary concrete). Compressive strength showed the largest increase under SS immersion in samples with low w/c (high-strength concrete), which was more visible than that in samples with high w/c. The increase in mass was greater for samples with high w/c than those with low w/c.The correlations between physical and mechanical parameters were investigated based on an analysis of the macroscopic physical and mechanical properties, micromorphology and composition of concrete samples in seawater-simulating corrosive solutions. The following conclusions were drawn:According to the findings, the monitoring of health and calculation of residual reliability for active concrete structures can be carried out using the relationship established in this paper. This method can also be generalized for other similar studies.


The purpose of this study was to evaluate the structural performance of composite deck slabs containing macro-synthetic fibers. after a fire by proposing a deflection estimation method for non-fireproof structural decks. Therefore, this study evaluated the fire resistance performance and deflection of deck slabs mixed with macro-synthetic fibers. Afterward, the deflection estimation method considering the thermal characteristics of concrete and deck plates was proposed. A material test was first conducted to evaluate the mechanical properties of concrete mixed with macro-synthetic fibers. This test found that the compressive strength and elasticity modulus of concrete mixed with macro-synthetic fibers was greater than that of general concrete. A flexural tensile test confirmed that residual strength was maintained after the maximum strength was achieved. The fire resistance of the deck slab was adequate even when a fire-resistant coating was not applied. The internal temperature was lowest for the specimen with macro-synthetic fibers. Deflection was evaluated using previously published equations and standards. The deflection evaluation confirmed that the temperature distribution should be applied differently in the estimation method that uses the thermal load of the deck slab. As buildings have become taller, the number of steel structures has increased. In the past, a steel deck was used only for formwork, in which a reinforcing bar was installed on the steel deck and concrete was poured. However, steel decks have been used recently as structural members, such as a composite structure in which concrete and deck plates are integrated. A composite deck slab is economical because temporary work is unnecessary, and it can even serve as a formwork. Therefore, it is possible to shorten the construction period, increase constructability, and reduce costs . BecauseWhen the composite effect of the deck plate and concrete is increased from the additional rib and Y-shape flange, the deck plate can transfer heat well to the concrete, even when exposed to high temperatures. For this reason, even if the bottom steel plate loses its tensile strength due to high temperatures, it is possible to prevent damage to the deck plate due to the ribs in the web. However, heat is transferred directly into the concrete due to the deck plate rib and Y-shape flange, and the internal temperature of the slab rises compared to the general RC slab. As a result, the water vapor pressure is greater than the internal stress of the concrete, causing spalling ,5. Becau3 PP fibers was shown to be up to four times greater than the permeability of concrete without fibers, and PP fiber contents of 2 kg/m3 showed no spalling when flamed [Researchers have attempted to reduce the internal temperature of concrete through reinforcement with fiber. Fiber-reinforced concrete (FRC) does not require upper temperature shrink reinforcement, so the constructability is expected to increase while the construction process decreases. Macro-synthetic fiber is easy to construct, is more effective at crack control than microfiber, and has high tensile strength ,3. Moreon flamed ,10,11. An flamed ,13,14.When evaluating fire resistance performance, the most important thing is whether the structural performance of the member is maintained until the fire resistance certification time determined by domestic and foreign standards ,18,19,20Accordingly, the deflection of members according to the fire resistance certification time determined by domestic and foreign standards is one of the important factors in evaluating the fire resistance performance, and the method is also presented in various ways through overseas standards and existing studies. Therefore, in this study, the deflection of the member was evaluated in the event of a fire. The thermal change characteristics of the deck plate and concrete were applied according to the temperature; then, the deflection was evaluated by comparing the experimental value and calculated value. The calculated value was based on the material’s mechanical curvature according to the load in the event of a fire and the equation for the fireproof design standard. Through this, the deflection of a deck slab incorporated with macro-synthetic fibers was evaluated and predicted according to the temperature during a fire, which allows for a safety inspection protecting against an actual fire occurrence ,19,20,212, a cross-sectional area of 13.04 cm2, and a thickness of 0.8 mm. The shape and specifications of the deck plate are shown in The deck plate used in this study was a hot-dip galvanized steel sheet with a product weight of 13.24 kg/mThe macro-synthetic fibers were polypropylene-based synthetic fibers that were 54 mm long, 0.34 m in diameter, and 159 in fiber shape ratio, which was used to confirm control of the explosion. The mechanical properties of macro-synthetic fibers were taken from the manufacturer’s data . The tenThe test variables for the deck slab test specimen were the presence or absence of a deck plate and the presence of macro-synthetic fibers. The concrete mix proportion table used in the deck slabs is shown in fc′ . The aveA flexural tensile test was performed with a three-point loading force by making a notch in the center of the specimen according to KS F 2408  and fib The deck slab specimen on which the fire resistance performance test was performed was manufactured in a rectangular shape with a size of 4700 mm × 3000 mm, including a 250-mm support at each end, as shown in The test specimen was cured for 3 months after pouring so that the moisture content of the concrete was suitable for the conditions of use of the slab. The fire resistance test was carried out in air-dry conditions.The fire-resistance performance test was conducted according to the KS F 2257-1  fire-resHere,t: Fire occurrence time (min)The fire-resistance performance evaluation of the test specimen was evaluated under the three conditions of load-bearing capacity, heat-shielding properties, and flame protection specified in the fire test method for KS F 2257-1 . When thHere,d: The distance from the position designed to receive the maximum compressive force of the structural section to the position designed to receive the maximum tensile force (mm)2, including the weight of the loading fixture.In addition, if the temperature of the non-heating surface of the test body increased by more than 140 K from the initial temperature during the fire test, it was judged as unsuitable in terms of heat-shielding performance. To evaluate the fire resistance, the test was performed by loading the upper part of the test sample with an equal distribution load according to the fire test standard, as shown in The fire-resistance performance test results are shown in In terms of heat-shielding properties, the non-heating surface temperature averaged 79.4 °C and the maximum was 102.1 °C for the RC-0 test specimen. None of the three test specimens exceeded the standard for backside rise temperature. In the fire-resistance performance test, none of the three specimens exceeded the standard values for the deformation, strain, and non-heating surface elevation temperature; they satisfied the fire resistance recognition time of 120 min for floor members, as specified in the fire resistance structure standard.When comparing RC-0 and Deck-0, the amount of deformation of Deck-0 decreased by 15 mm compared to RC-0. In general, when the internal temperature of concrete rises, the pressure of the internal aggregate itself increases, causing the concrete to expand and consequently deteriorating the performance of the concrete . HoweverIt was confirmed that bending cracks appeared in the center of all specimens. It is judged that crack occurrence and deflection changed despite no change in load as the flexural strength and stiffness decreased as the temperature of concrete, reinforcing bars, and deck plates increased.The internal temperature distribution for each specimen is shown in Between 20 and 60 min after the start of the fire resistance test, the temperature of the 30-mm deck slab specimen rapidly increased, then gradually changed after 60 min to show a similar slope to the RC-0 specimen. In the case of general concrete, the thermal conductivity of the concrete decreased due to a decrease in the mass of the concrete and the creation of voids as the temperature increased and the moisture inside escaped. In the case of the deck plate, after the initial moisture evaporation on the concrete’s bottom surface, heat transfer occurred actively, showing a rapid temperature increase between 20 and 60 min. After that, when the concrete reached a certain temperature, a temperature pattern similar to that of RC-0 appeared.To determine the heat transfer effect by the deck plate, the temperatures of the rebar at the 30-mm position and the concrete were compared, as shown in When checking the temperature change at the top, the temperature at 120-mm height inside the concrete was 134.3 °C on average in the Deck-0 test specimen compared with 114.6 °C for the RC-0 specimen and 102.6 °C for the Deck-2.4 specimen at the same location. It was measured at the highest temperature. This temperature difference is thought to be caused by smooth heat transfer from the deck plate to the concrete as heat rises through the ribs due to the ribs in the abdomen of the deck plate ,33.As shown in As the fibers were mixed, the lowest temperature was found in the bottom surface of the specimen. According to a previous study , polyproWhen checking the cross-section of Deck-2.4 after the fire test was completed, as shown in In case of fire, slab deflection evaluation requires analytical evaluation applying material properties. In this study, the deflection evaluation was performed through the deflection estimation formula presented in the previous study based on the temperature distribution derived from the experiment. When evaluating deflection by analysis, as shown in Equation (4), the total deflection of the member is expressed as the sum of deflection due to external load and deflection caused by temperature, which is calculated under the assumption of two conditions :(4)δtota-The sum of compressive stresses occurring in the member is always equal to the sum of the tensile stresses.-The moment generated by compression and tension force is the same as the applied moment.The neutral axis can be obtained based on the above two conditions. After calculating the strain through this method, the stress is calculated using the stress–strain equation. The nominal moment can be obtained from this stress, and the actual curvature can be considered when it is equal to the moment caused by the external load.Because the deflection of the member due to temperature increase is not due to the temperature load, the deflection equation obtained by integrating twice the moment cannot be used directly. Therefore, Equations (5) and (6) were obtained based on the fact that the slope of the linear strain and the curvature of the members are the same, and that the value obtained by dividing the moment by the flexural stiffness is the same as the curvature:Deflection due to thermal load was calculated using two assumptions—one caused by the moment at the end and one caused by the axial force at the end. To quantitatively evaluate deflection during a fire for a deck slab incorporated with macro-synthetic fibers, the creep strain based on the concrete temperature change according to the Anderberg model  and the When assuming that the deflection caused by the thermal load occurs due to the moment at the end, it can be calculated according to the general curvature derivation process. A case in which deflection occurs in a simply supported member is shown in Equations (9) and (10):l is the length of the member, Here, Second, when assuming that the deflection caused by the thermal load is caused by the axial force at the end, it can be calculated according to Equation (11). This method measures the deflection of the member due to thermal load according to the deformation of the main reinforcing bar of the member and shows the deflection equation according to the axial force :(11)υϕ,tConsidering the results of the deflection estimations for all specimens, the equation based on axial force more conservatively evaluated fire resistance performance than did the equation based on bending. The deflection estimation method described above is a method applied to a general RC slab. The actual deflection falls between the estimated deflection due to axial force and the estimated deflection due to bending.In the case of Deck-0, the internal temperature of the specimen was the highest among all specimens. However, the structural performance was expressed according to the composite of the deck plate and concrete to prevent deformation. In the case of Deck-2.4, the internal temperature of the specimen was the lowest among all specimens. The estimated sag was also the smallest because the rear surface temperature was reduced by up to approximately 30 °C and 90 °C by the macro-synthetic fiber compared with the other specimens. However, when compared with the actual experimental results, the estimated value of deflection due to bending was approximately 50 mm greater; when compared with the estimated value of deflection due to axial force, it was approximately 12 mm smaller.If the estimation of the temperature distribution considering the thermal characteristics of the deck slab and macro-synthetic fiber is derived in the future, the deflection of the slab in case of fire can be derived analytically without relying on experiments by applying the deflection evaluation method performed in this study.3 of macro-synthetic fibers. A fire resistance test was conducted according to KS F 2257 [(1)Based on the results of a fire test on the deck slab, RC-0, Deck-0, and Deck-2.4 all satisfied the fire resistance certification time of 120 min for the floor member.(2)Based on an analysis of the temperature distribution of the deck slab, the temperature increase was delayed in a section after a certain time, which is believed to have affected the overall temperature increase.(3)The internal temperature of Deck-0 was the highest compared with other specimens, but the deformation was the lowest. This is believed to have reduced the deformation of the deck plate because the composite effect increased due to the ribs arranged in the web and the Y-shape flange at the end of the ribs.(4)Based on an analysis of the thermal properties of the macro-synthetic fibers, Deck-2.4 (containing macro-synthetic fibers) had the lowest backside temperature compared with the other test specimens with a deformation difference of 16.7 mm compared with Deck-0. Therefore, the incorporation of macro-synthetic fibers is effective in preventing an increase in the temperature inside the slab, although it did not cause any reduction in the amount of deformation.(5)When estimating deflection due to thermal load for the deck slab, the temperature distribution should be applied differently for each method of estimating deflection. In addition, the method for estimating deflection due to axial force was found to safely evaluate the fire resistance performance of a deck slab.(6)If the estimation of the temperature distribution considering the thermal characteristics of the deck slab and macro-synthetic fiber is derived in the future, the deflection of the slab in case of fire can be derived analytically without relying on experiments by applying the deflection evaluation method performed in this study. In addition, it is necessary to analyze the effect of the length and angle of the rib and the Y-shape on the fire resistance performance of the deck plate later through finite element analysis.This study examined the thermal properties of non-fireproof deck slabs and macro-synthetic fibers. A total of three test specimens were produced: general reinforced concrete slabs, deck slabs, and deck slabs containing 2.4 kg/mS F 2257 . Through


Methionine (Met) is considered the most toxic amino acid in mammals. Here, we investigated biochemical and behavioral impacts of ad libitum one-week feeding of high-Met diets on mice. Adult male mice were fed the standard rodent diet that contained 0.44% Met (1×) or a diet containing 16 graded Met doses (1.2×–13×). High-Met diets for one-week induced a dose-dependent decrease in body weight and an increase in serum Met levels with a 2.55 mM peak  on the 12×Met diet. Total homocysteine (Hcy) levels were also upregulated while concentrations of other amino acids were almost maintained in serum. Similarly, levels of Met and Hcy (but not the other amino acids) were highly elevated in the cerebrospinal fluids of mice on the 10×Met diet; the Met levels were much higher than Hcy and the others. In a series of behavioral tests, mice on the 10×Met diet displayed increased anxiety and decreased traveled distances in an open-field test, increased activity to escape from water soaking and tail hanging, and normal learning/memory activity in a Y-maze test, which were reflections of negative/positive symptoms and normal cognitive function, respectively. These results indicate that high-Met ad libitum feeding even for a week can induce bipolar disorder-like disease models in mice. Methionine (Met) is one of the nine essential amino acids in mammals but is also the most toxic proteinogenic amino acid, whether expressed in terms of percentage of the diet or an increase over the nutritional requirement ,2. ExcesS-adenosylmethionine (SAM), the most predominant methyl donor for hundreds of methyltransferases. The enhancement of methylation reactions could be associated with unique toxicity, especially via negative transcription regulation, because glycine supplementation often alleviates the Met toxicity (probably through its self-sacrificing methylation to sarcosine [N-methylglycine] by glycine N-methyltransferase) ) or high-Met diets (1.2× [0.528%]–13× [5.72%]) for a week with free access to water. Body weights were not largely altered on the 1.2×Met–6×Met diets A, but thIntestinally absorbed Met is converted to Hcy in the liver via the Met cycle  and then to Cys via a transsulfuration that is composed of sequential enzymatic reactions catalyzed by CBS and CTH A. ThereaSerum levels of the other eight essential amino acids were generally maintained with the 1.2×Met–8×Met diets; however, those levels were slightly upregulated on the 9×Met–13×Met diets A–H. SimiWe had previously reported that Met accumulated highly in the CSF of 2-week-old CBS-deficient mice (488 µM compared to 24 µM in wild-type mice), an animal model of homocystinuria/homocysteinemia , and thap = 0.071).Several behavioral tests were conducted on mice fed with control (1×Met), 6×Met, or 10×Met diet for a week to explore typical symptoms observed in schizophrenic patients, including positive/negative symptoms and cognitive/memory dysfunction. In a conventional open-field test A, the tiWhen faced with emergency/unpleasant situations, such as water soaking and tail hanging, mice on the 10×Met diet displayed more excited behavior relative to the control fed mice; they struggled for a longer time to escape from the water G and taiCth−/−), demonstrating that transsulfuration played a critical role in the detoxification of excessive dietary Met  such as MDA) were examined using a TBARS assay kit .Male mice (8–11 weeks of age) were fed the control (1×Met) CE-2, 6×Met, or 10×Met diet for a week before behavior analyses. All behavioral activities were recorded using NVCap software  or an AGDRec desktop recorder  and analyzed by Fiji .The open-field test was performed to assess locomotor and exploratory activities as previously described . Each moThe elevated plus-maze test was performed as previously described . The appThe forced swim test was conducted as previously described . Each moThe tail suspension test was performed as previously described . Each moThe Y-maze test was performed to measure exploratory activity and short-term  memory ,34. A Y-


Social emergency medicine (EM) is an emerging field that examines the intersection of emergency care and social factors that influence health outcomes. We conducted a scoping review to explore the breadth and content of existing research pertaining to social EM to identify potential areas where future social EM research efforts should be directed.We conducted a comprehensive PubMed search using Medical Subject Heading terms and phrases pertaining to social EM topic areas  based on previously published expert consensus. For searches that yielded fewer than 100 total publications, we used the PubMed “similar publications” tool to expand the search and ensure no relevant publications were missed. Studies were independently abstracted by two investigators and classified as relevant if they were conducted in US or Canadian emergency departments (ED). We classified relevant publications by study design type , publication site, and year. Discrepancies in relevant publications or classification were reviewed by a third investigator.Our search strategy yielded 1,571 publications, of which 590 (38%) were relevant to social EM; among relevant publications, 58 (10%) were interventional studies, 410 (69%) were observational studies, 26 (4%) were systematic reviews, and 96 (16%) were commentaries. The majority (68%) of studies were published between 2010–2020. Firearm research and lesbian, gay, bisexual, transgender, and queer (LGBTQ) health research in particular grew rapidly over the last five years. The human trafficking topic area had the highest percentage (21%) of interventional studies. A significant portion of publications -- as high as 42% in the firearm violence topic area – included observational data or interventions related to children or the pediatric ED. Areas with more search results often included many publications describing disparities known to predispose ED patients to adverse outcomes , or the influence of social determinants on ED utilization.Social emergency medicine research has been growing over the past 10 years, although areas such as firearm violence and LGBTQ health have had more research activity than other topics. The field would benefit from a consensus-driven research agenda. In 1848 Rudolph Virchow declared social problems to be “largely within the jurisdiction” of physicians.While prior systematic reviews have examined the existing literature with a specific focus on material needs, there is a need to characterize the literature examining the broader field of social factors, including non-material factors – such as language, exposure to violence, and immigration status – known to influence emergency care and outcomes.This review was informed by the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) guidelines for scoping reviews. We identified 11 content areas based on a previously published systematic review of patients’ social and economic needs, including housing needs, employment needs, education and literacy, financial insecurity, personal safety , and food insecurity.We conducted a comprehensive literature search using a combination of Medical Subject Heading (MeSH) terms and phrases pertaining to topic areas . We restricted studies to those conducted in the US or Canada. Given the focus on social EM, we included the MeSH terms  OR (emergency (room[Title] OR department[Title] OR medicine[Title] OR care[Title] OR visit[Title])))). A full list of search terms can be found in We used the PubMed database for our searches, with the exception of the “Social Emergency Medicine Training” search, which also used the MedEd Portal database. For searches that yielded fewer than 100 total publications, we used the PubMed “similar publications” tool to expand the search and ensure no relevant publications were missed. Criteria for inclusion were as follows: (1) published in English; (2) conducted in the US or Canada through July 31, 2020; and (3) deemed relevant to social EM. Studies were considered relevant to social EM if they focused on social factors in the context of acute healthcare needs; therefore, we included the following criteria: 1) the study population consisted of ED patients or emergency clinicians; 2) the study or intervention occurred in the ED; or (3) ED utilization or outcomes were defined as a primary outcome.Once a publication was deemed to meet inclusion criteria we extracted additional information such as title, PubMed ID, year of publication, and study design type  into a standardized data collection form. We further catalogued observational and interventional publications by setting . For each publication, study objectives  were also recorded. For search results in each topic area, two co-investigators independently assessed each study for inclusion and relevance to social EM, Any discrepancies in relevance or categorization were reviewed and reconciled by a third reviewer. We also classified publications classified as relating to pediatric populations if they included children or adolescents (≤ 21 years) or if they were conducted in pediatric EDs.Our search strategy identified 1571 publications, of which 590 publications in 18 categories were classified as relevant to social EM. Depiction of search strategy and classification process are in We identified 62 relevant publications 66We identified 114 relevant publications: 71 observational studies156Other common study objectives included examining and amending the ED workflow for child abuse cases, developing screening protocols, and understanding provider knowledge and training with regard to child abuse in the ED. A plurality (42%) of the interventional studies involved evaluations of educational interventions for ED providers meant to improve child abuse screening and recognition.150We identified 31 relevant publications: 16 observational studiesWe identified 120 relevant publications: 78 observational studies290Of the 16 interventional studies, nine (56%) were related to screening,309We identified 19 relevant publications: four interventional studies353We identified 22 relevant publications: 14 observational studiesThe single interventional publication used pre/post data to evaluate the efficacy of an ED competency training in LGBTQ health.368We identified 24 relevant publications:399We identified 11 relevant publications: eight observational studies404We identified 32 relevant publications 438We identified 34 relevant publications470We identified 73 relevant publications541We identified 29 relevant publications 25 observational studies575Two relevant publications were identified,580We identified two relevant publications, both of which were observational.582Two relevant publications were identified, both of which were observational studies. One publication explored the association between educational attainment and patterns of ED use in patients with sickle cell disease,584We identified three relevant publications: two observational studies585We identified seven relevant publications590A total of three relevant publications were identified: one educational interventionWe identified 590 publications in 18 categories relevant to social EM, demonstrating a high degree of interest in social EM topics. Despite the large and growing number of relevant publications across categories, only 58 publications (10%) were interventional studies. In most topic areas, observational studies have already done a thorough job of describing and characterizing disparities by social identity and circumstance. For example, while a large number of studies looked at ways to effectively screen patients for things like interpersonal violence, health literacy, and human trafficking, there were few publications following up on outcomes for patients who screened positive. Even fewer interventional studies examined patient-oriented outcomes; most interventional studies were educational in nature, with outcomes such as clinician awareness and effectiveness of screening. The dearth of interventional studies examining patient outcomes underscores a need for funding to support testing and dissemination of potential interventions, given that observational studies are more feasible and less resource-intensive than interventional studies.Topics with the most published research included gun violence, child abuse, intimate partner violence, and housing/homelessness; these four categories combined constituted 63% of all relevant publications. There were several topic areas in which the literature base has grown rapidly in recent years, including gun violence and LGBTQ health. Topics such as elder abuse and incarceration have been the topic of few publications in the last five years, suggesting possible stagnation in these areas. About one third of the relevant publications included were related to the pediatric ED. We found very little research in the following eight topic areas: transportation, financial insecurity, education, employment, incarceration, racism, and legal needs, possibly because they may have been traditionally perceived as less directly related to clinical care and may thus have received less attention.Prior literature has examined the scope of EM research focused on material needs; our study also examines non-material social risk factors for health outcomes. While the acknowledgment of the interplay between social factors and patients’ acute health care needs and outcomes has existed in medical literature for decades, terminology such as “social emergency medicine” is more recent and has increased following a consensus conference about the field.7There were several limitations to our review. First, we largely used only the PubMed database, which may have left out relevant publications; however, we systematically searched PubMed, and a majority of biomedical publications are indexed in PubMed. All our search terms were specific to EM, which may have also left out research relevant to EM conducted in related settings or fields. We limited our search to “title only” rather than “title and abstract,” which may have also omitted relevant publications; however, after attempting both “title only” and “title and abstract” searches, we found “title only” searches to have much higher relevance. We also did not conduct a detailed analysis of publication quality, given that we set out to complete a scoping review rather than a systematic review; however, publication quality would have been difficult to assess across the diversity of topic areas given the vast array of topics and study designs. We maximized reliability by using two independent reviewers for each topic area, with a third reviewer who reconciled any differences in opinion regarding relevance or publication inclusion.Social emergency medicine research has accelerated in recent years. Numerous observational studies and commentary publications have defined and characterized problems relevant to social EM, and several educational interventions have demonstrated ways to improve provider awareness of different social EM topics. However, based on our review, there is a dearth of social EM research focused on patient-centered interventions. A consensus-driven research agenda should be pursued to accelerate patient-centered interventions aimed at social factors that influence acute healthcare and outcomes.


Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp, ESBL-producing Escherichia coli (E. coli), and MRO Acinetobacter baumannii (A. baumannii). Increasing carbapenem consumption was positively correlated with the occurrence of ESBL-producing Klebsiella spp and E. coli. Polymyxin use was positively correlated with ESBL-producing Klebsiella spp, MRO A. baumannii, and carbapenem-resistant Enterobacteriaceae. The findings reinforced concerns regarding the association between MRO development, especially with a surge in ESC and FQ consumption. Stricter use of antimicrobials is thus crucial to minimise the risk of emerging resistant organisms.Inappropriate use of antibiotics has been shown to contribute to the occurrence of multidrug-resistant organisms (MROs). A surveillance study was performed in the largest tertiary care hospital in Kuala Lumpur, Malaysia, from 2018 to 2020 to observe the trends of broad-spectrum antibiotics (beta-lactam/beta-lactamases inhibitors (BL/BLI), extended-spectrum cephalosporins (ESC), and fluoroquinolones (FQ)) and antibiotics against MRO  usage and the correlation between antibiotic consumption and MROs. The correlation between 3-year trends of antibiotic consumption (defined daily dose (DDD)/100 admissions) with MRO infection cases (per 100 admissions) was determined using a Jonckheere-Terpstra test and a Pearson’s Correlation coefficient. The antimicrobial resistance trend demonstrated a positive correlation between ESC and FQ towards the development of methicillin-resistant  In 2014, the World Health Organization (WHO) reported an alarming rate of resistance to multiple classes of antibiotics in common community-acquired and healthcare-associated infections such as Klebsiella pneumoniae, Escherichia coli and Staphylococcus aureus2. Once a pathogen acquires resistance towards antibiotics, the efficacy of treatment decreases substantially, limiting the therapeutic options and complicating the treatment outcomes. Inevitably, MRO infections are often associated with higher mortality rates3. Studies have reported that antibiotic resistance is a serious predicament, especially in tertiary care settings4. Patients are more susceptible to severe nosocomial infections, leading to poorer clinical outcomes, longer hospital stays, and higher health expenditure7. However, despite the rise in antibiotic resistance, there has been a downturn in the evolution of new antibiotics since the 1990s, primarily due to regulatory barriers, technical difficulties and low profitability compared to long-term medications for chronic conditions10. If this remains without any intervention, infectious diseases that were successfully eradicated in the past may resurface.The discovery of antibiotics in the early twentieth century has revolutionised infection control by saving countless human lives from bacterial infections. Nonetheless, pathogenic bacteria have since evolved and developed various resistance mechanisms against the antibiotics they were once susceptible to, leading to multidrug-resistant organisms (MROs)12. Although the Malaysian national data on antibiotic use and susceptibility/resistance patterns can be found in the annual National Surveillance of Antibiotic Resistance reports, Malaysian Statistics of Medicine, and National Antibiotic Guidelines (NAG), the antibiotic consumption and susceptibility profiles may vary in different localities 14. There is also a lack of evidence available in Malaysia that highlights the influence of broad-spectrum antibiotic usage toward the occurrence of MROs.Considering all the factors leading to antibiotic resistance, implementing antimicrobial stewardship programs (ASPs) is crucial to promote the judicious use of antibiotics, thus reducing antibiotic resistance. As such, periodic surveillance of antibiotic use and resistance at the local and national levels is vital to evaluate the effectiveness of ASPs and devise new strategies to address the gaps in the existing practicesTo address these existing gaps, the present study evaluated the 3-year trend of broad-spectrum antibiotics and antibiotics against MRO usage in Hospital Kuala Lumpur (HKL) and its influence on the occurrence of MROs. The main objectives of this study are to: (1) evaluate the trend of use of broad-spectrum antibiotics, (2) analyse the trend of occurrence of MROs and (3) determine the influence of broad-spectrum antibiotic usage on the occurrence of MROs. It was hypothesised that an increase in the trend of broad-spectrum antibiotics usage correlates with a surge in the occurrence of MROs.Quantitative research was conducted to analyse the three-year trend of systemic broad-spectrum antibiotics use and its influence on the MRO infection rates in HKL, a tertiary care hospital in Kuala Lumpur, Malaysia. It has 73 wards and 1570 beds with 19 clinical departments. Data on antibiotic consumption (expressed through DDD/100 admissions) was obtained from the pharmacy department, while MRO data were retrieved from the infection control department. The protocol was approved by the Medical Research Ethics Committee (MREC), Ministry of Health, Malaysia (NMRR-20-787-54141) and the Clinical Research Committee of HKL and in compliance with ethical principles outlined in the Declaration of Helsinki and Malaysian Good Clinical Practice (GCP) Guideline. The requirement for written informed consent from patients was waived by MREC due to the retrospective nature of the study. Furthermore, precautions were taken to ensure that all data and records confidentiality were only used for this study.15:Six groups of antibiotics that are classified under J01  according to the Anatomical Therapeutic Chemical (ATC) Classification System were included in this study. Broad-spectrum antibiotics selected for this study include amoxicillin/clavulanate, ampicillin/sulbactam, piperacillin/tazobactam, ceftriaxone, cefotaxime, ceftazidime, cefoperazone, cefoperazone/sulbactam, cefepime, ciprofloxacin and levofloxacin. Meanwhile, antibiotics against multidrug-resistant organisms (MROs) comprised of imipenem, meropenem, ertapenem, colistin, polymyxin B and vancomycin. Extended-spectrum cephalosporin (ESC) are cephalosporins with better activity against gram-negative microbes than first-generation agents. The following formula was used to calculate the defined daily dose (DDD) per 100 admissions (expressed as DDD/100 admissions) Staphylococcus aureus (MRSA), extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp, ESBL-producing Escherichia coli, multidrug-resistant organisms (MRO) Acinetobacter baumannii, carbapenem-resistant Enterobacteriaceae (CRE) and vancomycin-resistant enterococci (VRE). The MRO cases were followed up by Infection Control Team through discussions with primary prescribers to differentiate between infection and coloniser; colonisers data were then excluded from this study. The rate of MRO infection per 100 admissions was calculated using the following formula:The types of MROs analysed in this study were Methicillin-resistant p < 0.05. Data analyses were conducted using Statistical Package for the Social Sciences (SPSS) version 28.0 .Firstly, the Jonckheere-Terpstra test was performed to determine the trend of monthly antibiotic consumption, the proportion of pathogens and antimicrobial resistance rate over time. The J-T test is a non-parametric method to evaluate the presence of definite trend/order in the data. Separately, to evaluate the presence of linear relationship, Pearson’s correlation coefficient was used to investigate the association between antibiotic consumption and bacterial resistance rates. Statistical significance was defined at No patients were involved in this study. There was no plan to disseminate the results to the relevant patient community.The study was reviewed and approved by the Medical Research and Ethics Committee of the Ministry of Health, Malaysia (NMRR-20-787-54141).p < 0.001). Meanwhile, broad-spectrum antibiotics consumption increased by 37.6% and 31.7% in year 2020 from 2018 and 2019, respectively . Antibiotics against MRO showed a rising trend in 2020 by 46.2% and 40.6% from 2018 and 2019, respectively .Table Beta-lactam/beta-lactamase inhibitors (BL/BLIs) was the most frequently prescribed antibiotic groups , followed by ESC , carbapenems , glycopeptides , FQ  and polymyxins   throughout the 3-year observation.The top five most frequently prescribed antibiotics, which accounted for 77.8% of all antibiotic usage, were amoxicillin-clavulanate, ampicillin-sulbactam, piperacillin-tazobactam, ceftriaxone and cefepime. All the antibiotics exhibited increasing use throughout the study period except for ampicillin-sulbactam and piperacillin-tazobactam, which demonstrated a dip in 2019 and 2020. Consumption of amoxicillin-clavulanate, ceftriaxone, cefoperazone, cefepime, meropenem and ertapenem was significantly greater  (Table Klebsiella spp. (26.7%), ESBL-producing E. coli (19.6%), MRO A. baumannii (16.9%), CRE (8.2%) and VRE (0.5%) . Similarly, the VRE rate was significantly lower in 2020 compared to 2019 and 2018 . Figure The most isolated MRO pathogens between 2018 and 2020 was MRSA (28.0%), followed by ESBL-producing The correlation between antibiotic consumption and MRO occurrence is summarised in Table A. baumannii  and CRE . The consumption of ESC resulted in significant positive correlation for occurrence of MRSA , ESBL-producing Klebsiella spp , ESBL-producing E. coli  and MRO A. baumannii . Similarly, FQ showed significant positive correlation for occurrence of MRSA , ESBL-producing Klebsiella spp , ESBL-producing E. coli  and MRO . Carbapenem demonstrated significant positive correlation with ESBL-Klebsiella spp  and ESBL-E. coli . In comparison, polymyxins were associated with significant positive correlation for resistance of ESBL-producing Klebsiella spp , MRO A. baumannii  and CRE . VRE occurrence negatively correlated with the consumption of glycopeptides .Increasing BL/BLI consumption demonstrated significant negative correlation for occurrence of MRO 16. Jamaluddin et al. reported that empirical antimicrobials accounted for approximately 65% of prescribed antibiotics, notably throughout medical, surgical, orthopaedic and oncology wards in Malaysia17.The initial antimicrobial therapy is based on clinical judgments, emphasising likely pathogens while awaiting laboratory reports. Ideally, causative microorganisms’ identification enables the clinicians to select the most appropriate antibiotic, which improves overall patient outcomes18. Nevertheless, the culture and sensitivity results generally take more than 48 h to be available. Hence, the clinicians had to rely on the most likely organisms and site of infections for antibiotic selection17.The study reported the antibiotic usage and antimicrobial resistance patterns in the biggest tertiary hospital in Kuala Lumpur, Malaysia. Antibiotic Point Prevalent Survey of HKL in 2018 revealed that 88.5% of antibiotics prescribed was for empirical therapies14. Similarly, the reports from the Global Point prevalence study (PPS) revealed BLI and ESC are among the top three antibiotics prescribed worldwide18. Furthermore, the total utilisation of BL/BLI and ESC increased steadily every year, where a substantial increase was evident from 2019 to 2020 by 26.5% and 39.7%, respectively. Meanwhile, a significant rise in carbapenem, mainly ertapenem, was observed in this study. This might be related to the efforts of de-escalating broad-spectrum carbapenem such as imipenem or meropenem to ertapenem in ESBL infection. However, meropenem consumption increased steadily over the years as a preferred choice of empirical carbapenem due to its safety profile and convenient dosing.In this study, the most consumed antibiotics for hospitalised patients were broad-spectrum antibiotics subgroups, ESC and BL/BLI, comprising 86.4% of total antibiotic consumption. These results are comparable across Ministry of Health (MOH) hospitals, university hospitals, military hospitals, and private hospitals in Malaysia13. However, there was a hike in HKL’s entire antibiotic consumption trend, especially in 2020. Given that, Haug et al. suggested a few factors that can influence the variability in antibiotic consumption, including higher nurse staffing and larger proportions of shorter (< 2 days) and longer (> 10 days) hospital stays can lead to an increased antibiotic use19. Moreover, variations in local antimicrobial resistance patterns, physicians’ prescribing behaviour and workloads can also lead to discrepancies in antibiotic consumption21. Therefore, it is essential to consider these factors when comparing antibiotic utilisation with the national reports.Implementation of Protocol for Antimicrobial Stewardship (AMS) by MOH in 2014 was a successful approach to reduce unnecessary and inappropriate use of antibiotics, resulting in the decreasing trend of total antibiotic consumption in MOH hospitals. and Wushouer et al. found a significant correlation between broad-spectrum antibiotics use and MRO22. Furthermore, Barnes et al. concluded that the reduction in antibiotic use significantly reduces the rate of MRO occurrence23. In the present study, MRSA and ESBLs showed increased resistance patterns throughout the 3-year observation period. The increase in infection rate may result from high usage of certain antibiotic groups such as FQ and ESC and possibly poor infection control. A major part of healthcare-associated infections is avoidable through effective infection prevention and control strategy that will substantially contain antimicrobial resistance and outbreaks of highly transmissible diseases, including the COVID-19 pandemic. It is evident that infection rate can be contained by establishing local and national standard operating procedures (SOP), especially on five major components that include: (i) modification of system to facilitate good practice, (ii) training and educating healthcare personnel, (iii) observing health practices, procedures and outcomes and delivering timely feedback, (iv) refining healthcare message, and (v) adapting to a safety climate24. A study by Nori et al. on SARS-CoV-2 identified the most common opportunistic pathogens were S. aureus (44%), P. aeruginosa (16%), Klebsiella spp. (10%), Enterobacter. spp. (8%) and E. coli (4%) while MRO isolates were present in 15% of the testing25. The emergence of MRO CRE poses challenges to healthcare institutions globally, including Malaysia, since carbapenem is one of the ‘last-line antimicrobials where treatment options are limited, and higher mortality rates are reported compared to other MRO strains26. Moreover, the review of carbapenem at 72 h following AMS is believed to assist in carbapenems de-escalation to substantially reduce the risk of CRE27.MRO is one of the most crucial threats to national healthcare, typically associated with nosocomial infections. The indiscriminate and overuse of antibiotics, especially the broad-spectrum category, are the major factors associated with rising bacterial resistance. Studies by Meyer et alA. baumannii. Several studies described that ESC-resistant isolates were associated with gram-negative microorganisms’ production of ESBL, plasmid-mediated AmpCs, carbapenemase enzymes and MRSA occurrence29. In addition, Wushouer et al. reported significant positive correlations between MRSA infection rates and the consumption of third generation cephalosporins, carbapenems and glycopeptides22.Antibiotic resistance directly influences antimicrobial prescription by increasing the burden by mitigating certain classes of antibiotic class to another to reduce the selective pressure towards a particular antimicrobial class. Based on the current investigation, ESC and FQ had a stronger association with MRO than other antibiotic groups, including MRSA, ESBLs and MRO 30. Ryu et al. explained that the positive correlation between FQ and Klebsiella spp was related to the transferable plasmid (quinolone-resistant (qnr) gene) in ESBL-producing strains that lead to FQ resistance31. Klebsiella spp, especially K. pneumoniae, adapts well in the hospital environment and survives longer than other Enterobacteriaceae; thus, allowing for easier cross-infection, which deems for stricter control of the antibiotics in the future32. In the current study, carbapenem use showed a positive correlation with ESBL infections despite being used in the AMS strategy as the definitive treatment for ESBLs. Martìnez et al. reported that previous carbapenem use was a significant risk factor for ESBL-Klebsiella spp. and E. coli based on the possibilities of antibiotic enriching the gut reservoir with ESBL in patients already being colonised with a low number of microbes or promoting bacterial settlement following transmission event33. Besides, the positive correlation between polymyxins and ESBL-Klebsiella spp, MRO A. baumannii, and CRE may be linked to the chromosomal mutations of the carbapenem-resistant A. baumannii ST1 and CrrB single nucleotide polymorphism (SNP) mutants of polymyxins35.FQ consumption contributed to the prevalence of ESBL-producing pathogens, consistent with a surveillance study in China24. Interestingly, a negative correlation between BL/BLI and MRO A. Baumannii and CRE may have been contributed by reversed bacterial resistance mechanisms based on the antibiotic’s preferential targeting of specific cell wall assembly machinery36.The negative incidence of VRE to glycopeptides in the study may be linked to the comprehensive strategies that include appropriate dosing and duration of administrationIn order to curb the increasing antibiotic consumption trend, we have introduced several actions plans to improve antibiotic usage in our setting, including strict implementation of antibiotic request forms and antibiotic stop orders. The prescribers are required to submit an antibiotic request form upfront when prescribing six types of antibiotics, including meropenem, imipenem, ertapenem, vancomycin, colistin and polymyxin B. An antibiotic stop order is activated if these antibiotics are continued beyond 72 h, without any justification or evidence from culture and sensitivity results. In addition, our setting also embarked on persuasive antimicrobial stewardship initiatives such as education to all healthcare professionals through antimicrobial awareness week events and antimicrobial stewardship grand ward rounds.The study focused solely on the prevalence of antibiotic usage, primarily due to the nature of the cross-sectional study design. Other factors that could potentially influence antimicrobial use include the COVID-19 outbreak in 2020 and the patient case-mix. Therefore, the retrospective and observational study design cannot confirm the causal relationship between antibiotics consumption and MROs infection rates. Nevertheless, there was a positive correlation between the two variables. Therefore, the findings can suggest ways to reduce antimicrobial resistance. Furthermore, due to the different dosage requirements, antibiotic consumption was measured using DDD, which may be inaccurate and underestimates certain patient groups such as renal impairment. Therefore, it may not represent the prescribed daily dose for all patients.Moreover, there was a lack of patient-specific data for detailed risk factor evaluation. Since certain patients with a higher risk of MRO infection at baseline or cross-infection of MROs may affect the statistical significance, future research should include demographic data to address this gap. In addition, more data points (eg.10-year trends) should be considered to prove the correlation between antibiotics’ consumption and MROs infection.Klebsiella spp, ESBL-producing E. coli and MRO A. baumannii resistance. Continuous review and reinforcement of AMS in tertiary care settings are thus crucial to overcome the potential threats by MROs.The overall data presented a fair indicator for antibiotic use and resistance pattern in a tertiary hospital in Malaysia. Broad-spectrum antibiotics and antibiotics against MRO consumption increased significantly throughout the study, while the antimicrobial resistance trend in the hospital decreased, except for MRSA and ESBL. In addition, ESC and FQ consumption was positively correlated with the emergence of MRSA, ESBL-producing