Antimicrobial resistance (AMR) is a serious global public health challenge. Physicians’ over-prescription of antibiotics is a major contributor, and intravenous (IV) antibiotic use has been a particular concern in China. To address the rapid fallout of antibiotic overuse, the Chinese government has piloted a ban of IV antibiotics in the outpatient department (OD) with the exemption of paediatrics, emergency department (ED), and inpatient ward of secondary and tertiary hospitals in several provinces.To assess the potential impact of the policy, we conducted a mixed-methods study including 1) interviews about the ban of IV antibiotic use with 68 stakeholders, covering patients, health workers, and policy-makers, from two cities and 2) a hospital case study which collected routine hospital data and survey data with 207 doctors.Our analyses revealed that the ban of IV antibiotics in the OD led to a reduction in the total and IV antibiotic prescriptions and improved the rational antibiotic prescribing practice in the OD. Nevertheless, the policy has diverted patient flow from OD to ED, inpatient ward, and primary care for IV antibiotic prescriptions. We also found that irrational antibiotic use in paediatrics was neglected. Radical policy implementation, doctors circumvented the regulations, and lack of doctor-patient communication during patient encounters were barriers to the implementation of the ban.Future efforts may include 1) to de-escalate both oral and IV antibiotic therapy in paediatric and reduce oral antibiotic therapy among adults in outpatient clinics, 2) to reduce unnecessary referrals by OD doctors to ED, primary care, or inpatient services and better coordinate for patients who clinically need IV antibiotics, 3) to incorporate demand-side tailored measures, such as public education campaigns, and 4) to improve doctor-patient communication. Future research is needed to understand how primary care and other community clinics implement the ban.Supplementary information accompanies this paper at 10.1186/s12889-020-09948-z. Antimicrobial resistance (AMR) is the ability of microorganisms  to respond to the antimicrobial that once could successfully defeat them. AMR resulted in prolonged illness, increased mortality, and higher medical costs, and has become a serious public health challenge worldwide , 2. PrevAntimicrobial stewardship programs (ASPs), a systematic approach to rationalize the use of antimicrobial agents , are adoOveruse of injections when oral formulations would be appropriate is a major form of irrational use of antibiotics . The oveIn 2016, a few places including Zhejiang, Jiangsu, Shanxi, Anhui, Jiangxi, and Shanghai, piloted a ban on IV antibiotics use for outpatients in secondary and tertiary hospitals  . Before s. China has a three-tiered healthcare system. Community-based health facilities are expected to provide primary care, while secondary and tertiary hospitals provide referral care. However, there are no effective gate-keeping primary care mechanisms; as a result patients are free to choose whichever health facilities they prefer . (Policymaker)Although the ban aimed to reduce the IV antibiotic overuse in Chinese health facilities, most doctors thought that banning IV antibiotic use in the OD completely without a buffering period was unreasonable. However, the policymakers thought the radical approach was necessary to rationalize the IV antibiotic use in the OD.When I prescribe medicines for patients, I have to not only worry about whether the illness will be cured and how long it will take, but also worry about the percentage of medicine cost out of the total cost per prescription, the antibiotic use rate, and consider how much revenues I make for my hospital. I feel like I need to be not only a doctor but also an actuary. (Outpatient doctor)To reach the target percentages set by the Health Bureau, hospitals supervised every individual doctor’s antibiotic prescribing rate every month. Consequently, there was a financial penalty if s/he did not achieve the target percentage. Some doctors found countermeasures to meet those target indicators and avoid the financial penalties rather than de-facto improvement in prudent antibiotic use.Our hospital calculates the antibiotic use rate for each doctor every month. If anyone exceeds the rate, s/he will be fined. At the end of each month, I sometimes had to call my relatives and friends to visit me and prescribed them medicines without antibiotics. Therefore, my antibiotic prescribing rate was reduced because the prescriptions for my relatives and friends increased the denominator. (Outpatient doctor)When I met some patients asking for antibiotic use, I sometimes prescribed the patient with more diagnostic tests when I run out of my quota to prescribe antibiotics. After the patient completed the tests and got the results, it had been in the afternoon or the next day when I have been off work. So it delayed prescribing antibiotics and transfer it to other doctors. [If the patient were prescribed with antibiotics] it did not count on my head. (Outpatient doctor).At the beginning days of a month, most of the patients who expected antibiotics from me would get one. However, for those patients who come in the remaining days of a month when the hospital calculates our antibiotic prescription rate, it is difficult for me to prescribe them because I would exceed my quota in that month. I would refer them to other doctors who still have some quota left if the patient does need antibiotics. (Outpatient doctor)Doctors complained that the policy’s requirements of performance targets of antibiotic prescriptions had seriously harmed clinical autonomy in their daily practices.For most of the outpatient doctors, our consultation workloads have already been heavy. We would rather spend two minutes to refer the patients who insist on using IV antibiotics to the ED than spending another 10 to 15 minutes to educate and convince the patient not to use IV antibiotics. (Outpatient doctor)I do not have much time to communicate with patients. If patients come to demand IV antibiotics, I will prescribe one. (Emergency doctor)Secondly, poor doctor-patient relationship in China was believed to be an obstacle to effective doctor-patient communication. Due to the perceived poor doctor-patient relationship, doctors were inclined to meet patient expectations and became reluctant to address any potential patient complaints.I need to be very careful when I explained the policy of IV antibiotic use ban and tried to educate the patients not to use unnecessary IV antibiotics. Sometimes patients thought I was the person who did not allow them to use IV antibiotics. If anything unexpected happens to the patients, they think that I must take the responsibility. (Emergency doctor)If I refuse to prescribe some patients with IV antibiotics, they will say: 'If you don’t prescribe infusion for me and if anything happened to me, you need to take the responsibility.’ The disease itself is complicated, you know. There are many situations out of my control. I can’t take the risk. (Emergency doctor)When the patients asked for IV antibiotics in the OD, most doctors responded to those patients by referring them to other services directly where IV antibiotics were available rather than properly educating the patient. There were two main reasons. Firstly, it was more time-consuming to conduct health education.Tackling IV antibiotics overprescribing is a top priority of China’s ASPs initiative. One of the key measures adopted is a top-down health policy that completely bans IV antibiotic use in outpatient departments, starting with tertiary hospitals. To the best of our knowledge, our study was the first to evaluate the influence of such a policy in Zhejiang Province. We found that the ban has successfully reduced the gross antibiotic prescriptions, IV antibiotic use, and combination antimicrobial therapy in ODs. Fewer restricted and special grades antibiotics were prescribed as well. However, unintended effects were observed. These included driving some patients to health services which had less strict control of IV antibiotic use, such as ED, inpatient services, and primary care facilities, subsequently causing more wastage of health resources at these service sections.Firstly, we found a positive impact of the ban on the reduction of the total antibiotic use, IV antibiotic use, and combination antimicrobial therapy. This is consistent with Gong et al.  that theSecondly, we also found unintended consequences among which patient flow to other service departments or sectors, either through self-referral or a physician referral, for IV antibiotics became the most prominent. A similar balloon metaphor phenomenon was reported in medical cost control and antibiotic resistance before , meaningThirdly, complaints and concerns about the radical policy implementation without a buffering period were common among physicians in ODs. Besides, physicians had their way to circumvent the policy. Without prescribing quality assessment, these countermeasures adopted by physicians caused concerns about the reliability of such digital indicators as a main quality control measure. It is worth policymakers’ revisit of the reliability of these digital indicators and consideration of integrating quality assessment of randomly selected prescriptions to improve the clinical rationality of antibiotic prescribing. More importantly, AMR is a public health risk that requires multisectoral efforts to tackle, including health care providers and service users as the two key stakeholders. However, the current policy led to an unexpected shift in the “location” of risk . Doctors faced risks of a fine following unmet hospital performance evaluation criteria, fear of violence from dissatisfied patients, and constrained time for patient communication in the clinical settings. These factors drove doctors to simply adopt the above risk-shifting behaviours which may compromise their professionalism. We found that within the hospitals, the risk of AMR shifted from one doctor to another doctor in OD or from the OD to the ED, primary care, and inpatient services.Lastly, the policy focused on the supply side only and neglected the patient side. Previous research showed that Chinese patients held high expectations on IV antibiotics , 42, sugAll in all, despite some positive effects, banning IV in outpatient services at hospitals is not a panacea, and general public education to improve public understanding is also essential for minimizing unintended adverse consequences such as patient flow to other service departments or sectors for unnecessary antibiotic treatment. A socio-ecological model to address the determinants for IV antibiotic use from the individual, community, institutional, and policy levels along with a communication for development approach  for inteThis study has some limitations. First, we cannot identify narrow-spectrum and broad-spectrum antibiotics in the health information system to assess the appropriateness of antibiotic therapy. However, we used the non-restricted, restricted, and special antibiotics classified by the Chinese NHC which to some extent illustrated the improvement in antibiotics use. Secondly, the hospital records we obtained did not include lab results about the bacteria or other pathogen a patient had (if any) to enable us to assess the appropriateness of antibiotic therapy. Thirdly, the survey with the doctors about whether they would refer patients to other departments to get IV antibiotics was a sensitive topic for them. Thus, respondents might give socially desirable answers in a self-administrated questionnaire. However, the reported percentages of referring patients to other departments were high, which suggested that they have been quite honest, and the survey should be a success. Nevertheless, we conducted a qualitative study, and the results were consistent with the survey findings. Lastly, our study only targeted the effect of the ban in Zhejiang province, an economically developed region, which may not be representative of poorer areas in China. However, we selected multiple sites, facilities, and enrolled different stakeholders in our study. The findings may be useful to inform future research about other areas of the nation or countries with similar settings.Our study has several implications for China’s national ASPs. A complete ban of IV antibiotic use in OD may successfully lower gross antibiotic use, IV antibiotic use, and combination antibiotic therapy, but increased oral antibiotic use in adult and neglected paediatric antibiotic overuse represents challenging unintended consequences. Further, more research attention to other unintended consequences is highly warranted. These unexpected consequences included more patient flow to ED, inpatient ward, and primary care services with the main purpose of obtaining IV treatment, along with physicians’ risk-shifting behaviours. Multi-faceted interventions targeting both health care providers and service users were highly recommended to facilitate behavioural change and improve rational antibiotics use among the two key groups . Future Additional file 1 Interview guide. File providing the details of the questions designed and used as a study tool during the interviews.


Heavy metal pollution, such as lead, can cause contamination of water resources and harm human life. Many techniques have been explored and utilized to overcome this problem, with adsorption technology being the most common strategies for water treatment. In this study, carbon nanofibers, polyacrylonitrile (PAN)/sago lignin (SL) carbon nanofibers (PAN/SL CNF) and PAN/SL activated carbon nanofibers (PAN/SL ACNF), with a diameter approximately 300 nm, were produced by electrospinning blends of polyacrylonitrile and sago lignin followed by thermal and acid treatments and used as adsorbents for the removal of Pb(II) ions from aqueous solutions. The incorporation of biodegradable and renewable SL in PAN/SL blends fibers produces the CNF with a smaller diameter than PAN only but preserves the structure of CNF. The adsorption of Pb(II) ions on PAN/SL ACNF was three times higher than that of PAN/SL CNF. The enhanced removal was due to the nitric acid treatment that resulted in the formation of surface oxygenated functional groups that promoted the Pb(II) ions adsorption. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. The adsorption data fitted the Langmuir isotherm and the pseudo-second-order kinetic models, indicating that the adsorption is a monolayer, and is governed by the availability of the adsorption sites. With the adsorption capacity of 588 mg/g, determined via the Langmuir isotherm model, the study demonstrated the potential of PAN/SL ACNFs as the adsorbent for the removal of Pb(II) ions from aqueous solution. Heavy metals can contribute to environmental problems, which could have an impact on humans due to its toxicity. The heavy metal pollution could bring an implication to the aquatic life bodies, natural water bodies, and possibly get trapped in the soil through bioaccumulation . Its higNatural polymers received massive attention from the researchers in order to reduce the consumption of petroleum-based polymers . CelluloSynthesis of carbon materials particularly CNFs from renewable resources such as biomass has scarcely been reported. Mamun, Ahmed  implemenSEM images of PAN nanofibers electrospun using various concentrations of PAN solutions are shown in 2, and –CH3) are observed at around 2900 cm−1, 1450 cm−1, 1350 cm−1, and 1220 cm−1, respectively. The peak at 2200 cm−1 can be assigned to the nitrile group, C≡N [−1 is due to the C=O group from the trace of DMF solvent that did not evaporate during the drying process [−1 is assigned to –OH stretching peak either alcoholic or hydroxyl group of sago lignin. The peak at 1617.76 cm−1 represented the C=C stretching of the benzene skeleton [−1 is attributed to C–H bending vibration in methyl groups while the peak at 1069 cm−1 is assigned to C–O deformation in secondary and primary alcohols or aliphatic ether [−1 and the absorption peaks between 2200 and 2100 cm−1 were assigned to the C≡N nitrile group. At around 1100 cm−1, a peak appeared which can be assigned to C–O deformation of the benzene ring in lignin structure while at peak between 780 and 800 cm−1, the peaks were contributed by the bending of C–H groups of lignin’s benzene ring.Electrospun PAN/SL fibers were prepared by blending PAN and sago lignin (SL) with the ratio of SL to PAN varied from 10% to 50%, using DMF as a solvent. oup, C≡N . C=O car process . For sagskeleton . The peaDue to the lack of chain structures and/or molecular entanglements of lignin, lignin alone could not be electrospun into nanofibers ,31. Ther−1 to 2400 cm−1, indicating a conversion of C≡N into C=N as a result of cyclization and cross-linking of PAN into the ladder-like structure during stabilization. The absorption peak around 1570 cm−1 belonged to a mix of C=N, C=C, and N–H groups and the appearance of C=C was due to dehydrogenation [3, HCN, and N2 disappeared. The peak between 1680 cm−1 and 1530 cm−1 was assigned to the stretching and bending of C=C groups while the absorption peak around 1100 cm−1 was due to C–H deformations [genation . After crmations .2, CO, NH3 and HCN and the densification of carbon atoms in the polymer chains during thermal treatment [PAN nanofibers and PAN/SL nanofibers underwent stabilization and carbonization and will be denoted as PAN CNFs and PAN/SL CNFs. In reatment ,36. The determination of carbon yield was conducted using TGA under an inert atmosphere according to previously reported by Thunga et al. . The car−1 for PAN/SL ACNFs and was attributed to the presence of more –OH groups probably due to phenolic groups after modification with HNO3 [−1 and 1547 cm−1 were observed for PAN/SL ACNFs and CNFs can be assigned to highly conjugated carbonyls (quinone groups) and C=C stretching vibrations of aromatic rings [−1 belong to symmetric NO2 stretch vibrations which indicates that NO2 groups were successfully introduced on the surface of carbon fibers upon HNO3 treatment [−1 and 1103 cm−1 were assigned to C–O deformations which can be observed for both PAN/SL ACNFs and CNFs.After the carbonization process, PAN/SL CNFs were subjected to an activation step to produce activated PAN/SL CNFs (PAN/SL ACNFs). This step modified the surface of PAN/SL CNFs using concentrated nitric acid. ith HNO3 . Peaks aic rings ,41. Thisreatment . The pea2 adsorption–desorption isotherms of (a) PAN/SL CNFs and (b) PAN/SL ACNFs. From the graph, N2 adsorption–desorption was lower for PAN/SL ACNFs which might be due to the limited amount of pores necessary for N2 adsorption. 2 adsorption–desorption isotherms of PAN/SL CNFs and PAN/SL ACNFs. These data demonstrate that after activation with HNO3, the total surface area was significantly decreased from 292.24 to 57.37 m2/g accompanied by a widening of the average pore diameter. The widening of average pore diameter after activation suggests the effective attack by nitric acid on the micropores, resulting in the partial destruction of their structure [tructure ,44. The tructure .1s, O1s, and N1s spectra are shown in 1s binding energy (BE) of PAN/SL ACNFs composed of three components assigned to carbon atoms of the polymer chain. BE of C1s that was located at 283.6 eV was assigned to C–C and C=C bonds of a graphitic structure [1s of PAN/SL ACNFs consist of three BE bands. The band at 529.7 eV was assigned to C=O groups while the band at 532.9 eV was due to oxygen in phenolic groups, C–O–H which is common in the lignin structure [1s only consists of one band at 397.1 eV that was assigned to pyridinic N which is due to the nitric acid treatment [The activation of PAN/SL ACNFs with nitric acid was further characterized using XPS analysis to study the chemical structure and elemental composition on its surface . The C1structure . The BE tructure . The BE tructure . The XPStructure . BE at btructure . On the reatment .3, as evidenced by FTIR and XPS analyses. The attachment of surface oxygen groups decreases the hydrophobicity of the adsorbent surface, thus improves the interaction with Pb(II) ions and promotes the Pb(II) ion adsorption on the PAN/SL ACNF [/SL ACNF . Since the time taken for the adsorption process to achieve equilibrium is of considerable significance to develop economical heavy metal adsorbents, the effect of contact time on the percentage removal of Pb(II) ions by PAN/SL ACNFs was investigated. As depicted in The effect of adsorbent dosage on the percentage removal of Pb(II) ions and the adsorption capacity, q is illustrated in 2 at pH above 7. The effect of the initial pH solution, conducted at a pH range of 1 to 7, on the removal of Pb(II) ions is as shown in + ions and Pb(II) ion can also lead to a reduction in percentage removal. The removal of Pb(II) is more significant at a pH range of 4 to 7, with the highest removal of 67% observed at pH 5–6. The enhancement of the percentage removal was due to the electrostatic attraction between the Pb(II) ion and the negatively charged surface of the adsorbent.The adsorption of Pb(II) ions on PAN/SL ACNFs at different pH values is affected by the surface properties of the adsorbent and the speciation of the metal ions. The pHpzc of the adsorbent, as determined using the pH drift method, was 3.8, which indicates that the surface of the adsorbent was positively charged at pH below 3.8 and negatively charged at pH beyond 3.8. Pb(II) ions are known to precipitate as Pb(OH)1 and k2 are the rate constants, and qt and qe are the amounts of Pb(II) adsorbed at time t and equilibrium, respectively. The adsorption mechanism of Pb(II) was investigated by fitting the experimental adsorption data to several kinetic models, namely, pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The linearized form of the pseudo-first-order and pseudo-second-order is as shown in Equations (1) and (2), respectively;e, rate constants, and the correlation coefficient (R2) values at different initial concentrations of Pb(II) solutions. The R2 value of the pseudo-second-order model is closer to unity. Besides, the experimental qe is also comparable to that of the calculated qe of the pseudo-second-order model. These results show that the kinetics of Pb(II) adsorption onto PAN/SL ACNFs can be described well by the pseudo-second-order model, suggesting that the adsorption process is governed by the availability of the adsorption sites rather than the concentration of the Pb(II) ions [II) ions .2, increased with increasing Pb(II) concentration up to 125 mg/L, before decreasing with further increases in the initial Pb(II) concentration. The initial increase of k2 may be due to increase driving force for mass transfer with increasing Pb(II) concentrations. However, at higher Pb(II) concentration, although the qe increased, the k2 decreased. This decrease could likely be due to competitive adsorption between Pb(II) ions (highly concentrated) towards the limited adsorption sites and diffusion of metal ions from the surface to the interior adsorption sites of the adsorbent.As shown in id is the intra-particle diffusion rate constant (mg/g.min1/2) and C is the intercept which is related to the boundary layer thickness. id,  as follows:ess. id,  at Pb(IIe (mg/L) and qe (mg/g) is the concentration of metal ions, and the amount of metal ion adsorbed at equilibrium, respectively, while qm (mg/g) is the maximum adsorption capacity. KL (L/mg) is the Langmuir constant that is related to the affinity of the binding site, whereas n and KF are Freundlich constants related to adsorption intensity and adsorption capacity, respectively. As shown in 2 value for both the Langmuir and Freundlich isotherm model is near unity, indicating that the adsorption of Pb(II) ions on PAN/SL ACNFs fitted both adsorption models. However, the calculated qe values of pseudo-second-order kinetics for Pb(II) concentrations of 150 and 175 ppm  ions took place on the surface of the adsorbent. Hence, the adsorption process can be said to follow the Langmuir isotherm model with qm of 588.24 mg/g and KL of 0.2537 L/mg.The adsorption isotherm is essential for validating an accurate prediction of adsorption parameters and quantitative analysis of adsorption behavior for various adsorbent systems and conditions . In this 175 ppm  are the The adsorption of Pb(II) by PAN/SL ACNF was compared to that of other carbon-based adsorbents reported in the literature, and the results are shown in wt/v)) for the preparation of electrospun PAN fibers. The solutions were stirred at room temperature until homogenous solutions were obtained. Electrospun PAN/SL fibers were prepared by blending PAN with SL with a ratio of lignin to PAN varied from 10% to 50% using DMF as the solvent. The polymer blend was stirred at room temperature until the polymers were dissolved completely.The isolation of sago lignin from sago waste was conducted in accordance with Schwanninger and Hinterstoisser  with a sFor the electrospinning process, the polymer solution was loaded into a 5 mL syringe attached with a 0.8 mm inner diameter needle. The distance between the needle tip and the aluminum foil collector was fixed at 10 cm. The electrospinning was conducted using 18 kV voltage with a 2 mL/h flow rate. The nanofibers formed on the collector was collected and dried in the oven overnight. PAN nanofiber and PAN/SL nanofibers undergone two steps of thermal treatment to transform into CNFs. The electrospun nanofibers were thermally stabilized at 250 °C for 1 h in the air. The sample was then carbonized in a tube furnace at 1000 °C for 1 h under nitrogen gas flow. The carbon nanofiber produced from PAN nanofiber and PAN/SL nanofiber was denoted as PAN CNF and PAN/SL CNF, respectively. The PAN/SL CNF was then activated, to produce PAN/SL ACNF, according to Ihsanullah et al. , with sohttps://imagej.net/Downloads) with 200 readings per sample. The infrared spectrum of the samples, before and after activation, was recorded in the range of 4000 to 280 cm−1 on an attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometer  to determine the functional groups of the samples. Thermal gravimetric analysis (TGA), Mettler Toledo Thermogravimetric Model TGA/SDTA, was used to determine the thermal stability and carbon yield of the CNFs. The samples were heated from 35 °C to 1000 °C with a heating rate of 10 °C/min under a nitrogen atmosphere, and the amount of weight loss as a function of temperature was examined. X-ray diffraction (XRD) is an ideal method for characterization and identification of crystalline phase of the nanofibers and CNFs. The powder was put in specific mould and diffraction was generated by CuKα radiation. The analysis was carried out using Shimadzu Model XRD-6000  and the 2θ range from 20 to 600 with scanning rate of 20/min were used. The surface area and porosity of the prepared carbon fiber were determined by N2 adsorption measurements at 77 K on a BELsorp Mini II. The surface area of the carbon fibers was obtained using the Brunauer-Emmet-Teller (BET) method. At the same time, the porosity (pore volume and average pore diameter) was evaluated using the Barret, Joyner, and Halenda (BJH) method. X-ray photoelectron spectroscopy (XPS) was carried out on a PHI 5000 ESCALAB MKII instrument  with an Al Kα anode. XPS was used to examine the chemical composition of the ACNFs and the attachment of oxygenated functional groups. A monochromatic X-ray beam source at 1638.4 eV  was used to scan the sample surface. All binding energies were referenced to the neutral C1s peaks at 284.8 eV. The narrow scan data were used to determine probable compounds for the C, O, and N peaks [initial = pHfinal line was taken as pHpzc [The morphology of the nanofibers was imaged using scanning electron microscopy, SEM , and the average fiber diameter was determined using ImageJ software 2 salt with deionized water in 1000 mL volumetric flask. Different initial concentrations of Pb(II) ion solutions were prepared by diluting the stock solution. The adsorption of Pb(II) was conducted by contacting 100 mg/L Pb(II) solution with 25 mg each of PAN CNF and PAN/SL CNFs at pH 5. The experiments were conducted in a 250 mL conical flask and the solution mixture was magnetically stirred at 200 rpm for 240 min at room temperature. After specified time intervals, the solution mixture was collected and analyzed using an inductively coupled plasma-optical emission spectrometer .The adsorption of Pb(II) ions by PAN CNFs and PAN/SL CNFs was studied using the batch adsorption method. The stock solution of Pb(II) ions (1000 ppm) was prepared by dissolving 1.5980 g of Pb(NO0 (mg/L) is the initial concentration of Pb(II) ions, Ct (mg/L) is the concentration of Pb(II) in solution at time t, V (L) is the volume of Pb(II) ions solution, and m (g) is the mass of adsorbent.To optimize the adsorption process, the one factor at a time method was used. The four parameters used in the optimization experiments were adsorbent dosage (25–100 mg), contact time, initial concentration of Pb(II) solution (75–175 mg/L) and pH of the solution (1–7). The pH of the solution was adjusted to the desired value by the addition of either 1.0 M HCl or 1.0 M NaOH solution. The percentage of removal of Pb(II) and the adsorption capacity was calculated using Equations (6) and (7), respectively.3 due to the presence of surface oxygen groups. The best-suited adsorption conditions that gave the highest percentage removal of 67%, with an adsorption capacity of 524 mg/g, were 40 mg of adsorbent dosage, 125 ppm of Pb(II) solution, pH 5, and a contact time of 240 min. It was determined that the pseudo-second-order kinetic model was well-fitted with the experimental data which indicates that the adsorption process was controlled by chemisorption. From the intra-particle diffusion multilinear plot, it was suggested that two steps of adsorption were involved in the adsorption of Pb(II) ions. Besides, the adsorption process can be said to follow the Langmuir isotherm model with qm of 588.24 mg/g. These results imply that PAN/SL ACNFs are effective adsorbent for the removal of Pb(II) from aqueous solution and have the potential to be used as the adsorbent for wastewater treatment.In this study, PAN/SL ACNFs were successfully prepared by incorporating sago lignin into PAN via a simple and versatile technique which is electrospinning. PAN/SL ACNFs have shown significantly higher percentage removal of Pb(II) by three times after activation with HNO


The three ILs-POSS were synthesized via a green chemistry approach—a thiol-ene “click” reaction without metal ions as catalysts. Furthermore, the spherical vesicle structures of the ILs-POSS were observed and caused by self-assembly behaviors. Through comprehensive characterizations, these ILs-POSS have performed excellent thermal stabilities and low glass transition temperatures. In addition, we found it very meaningful that the limits of detection (LODs) of the three ILs-POSS for the detection of the Fe3+ ion were 7.91 × 10−8 M, 1.2 × 10−7 M, and 1.2 × 10−7 M, respectively. These data illustrate that these ILs-POSS have great potential for the detection of the Fe3+ ion. In conclusion, this study not only prepared novel ILs-POSS, but also provided new materials as fluorescent sensors in the detection of Fe3+.This study reports a novel series of imidazolium ionic liquids (ILs) based on polyhedral oligomeric silsesquioxanes (POSS) towards effective detection of metal ions, especially Fe3+ ion.  In recent years, ionic liquids (ILs) have been widely applied in numerous chemical engineering fields such as eletrochemical sensors , catalysHowever, some certain conditions have limited the development and employment of ILs. Thus, it is urgent to produce a more multifunctional and composite new class of ILs.Over the past decades, polyhedral oligomeric silsesquioxanes (POSS)  have pla2) under mild conditions. Akbari [The study of the preparations and applications of ILs-POSS have been reported by many researchers over the decades. For example, Chen  reported. Akbari  prepared3+ as an indispensable trace metal element in living organisms [3+ exceeded the limit, it would cause disorders of the pancreas [3+ could cause anemia [3+. In addition, the United States Environmental Protection Agency (UEPA) and the World Health Organization have set a limit of Fe which is no more than 5.4 μmol/L [3+ has great significance [3+ have attracted much attention due to their high sensitivity, simplicity, cost-effectiveness, and fast response times [Ferganisms  has playpancreas , the heae anemia . It is ke anemia . Along w4 μmol/L , therefoificance . Traditiificance . In addise times .3+ in order to expand the fields of ILs and silicone materials.Imidazolium functionalized ILs-POSS have performed strong fluorescent abilities and been employed in the detection of metal ions . NeverthThe starting materials  were purchased from Aladdin Co.  and used without further purification. 2,2-dimethoxy-2-phenylacetophenone (DMPA) was purchased from the Aladdin Co.  and used as received. Tetrahydrofuran (THF) and toluene were purified and distilled over sodium before use. The routine procedure was as follows: Benzophenone was used as an indicator, and sodium metal was added to the THF, which was heated until the solution was dark blue. Octa(mercaptopropyl)silsesquioxane (denoted as POSS-SH) were prepared according to a method described in the literature .1H NMR, 13C NMR, and 29Si NMR spectra were recorded on a Bruker Avance-400 spectrometer  using CDCl3 or a mixture of CD3OD and acetone-d6 as the solvent and without tetramethylsilane (TMS) as an internal reference. High resolution mass spectra (HRMS) were obtained in the negative mode on an Agilent Technologies 6510 Q-TOF mass spectrometer . FTIR spectra were recorded on a Bruker TENSOR-27 infrared spectrophotometer  via the KBr pellet technique within the wave number region from 4000 to 400 cm−1. Luminescence (excitation and emission) spectra of the samples were recorded with a Hitachi F-4500 fluorescence spectrophotometer  equipped with a monochromatic Xe lamp as an excitation source. Thermal measurements were carried out using a TA Instruments SDTQ 600 . The ILs-POSS were loaded into aluminium pans, which were then heated from −150 to 40 °C, cooled to −150 °C, and finally reheated to 40°C. The heating and cooling temperature ramping rates were 10 °C/min. The differential scanning calorimetry (DSC) data reported in this paper were from the second heating cycle. TGA was performed on a Mettler Toledo TGA/DSC1  at a heating rate of 10 °C/min from room temperature to 700 °C under N2 (10 mL/min) at ambient pressure. To analyze the self-assembly behaviors of the ILs-POSS by TEM observation, samples were prepared by spreading a drop of aggregated solution onto a copper grid, followed by air drying at room temperature before testing on a JEM-1011 (100 kV) electron microscope .3OH and CH2Cl2. The starting materials were then irradiated with a UV lamp for 15 min after dissolving completely. Finally, IL1-POSS was obtained after solvent evaporation at low pressure and vacuum drying at 60 °C for 24 h. The yield of IL1-POSS was 91%. IL2-POSS (yield: 92%) and IL3-POSS (yield: 90%) were prepared in the same way as above. The thiol-ene reaction mixture was irradiated with high-intensity UV light from a Spectroline model SB–100P/FA lamp . As illustrated in In this paper, we prepared a series of ILs-POSS: IL1-POSS, IL2-POSS, and IL3-POSS. The synthetic routes are described in −1) was consistent with the appearance of peaks that were assigned to the imidazole ring at 1579 and 1446 cm−1. In the meantime the peaks of the carbonyl group were around 1730 cm−1, as shown in 1H NMR spectra of the ILs-POSS are shown in 2 peak at approximately 5.5–6.0 ppm vanished  of the ILs-POSS ranged from 200 °C to 300 °C  and differential scanning calorimetry (DSC) were performed. The thermal decomposition temperatures (Tshown in . For insg) , we obtained the LOD value of the three ILs-POSS, which were LOD1 = 7.91 × 10−8 M, LOD2 = 1.2 × 10−7 M, and LOD3 = 1.47 × 10−7 M. In conclusion, the three ILs-POSS could be used to detect Fe3+ at extremely low concentrations.Illustrated by the Stern–Volmer curves shown in 3+, which demonstrates that ILs-POSS have potential application in the field of fluorescent sensors.Based on the data above, the ILs-POSS performed excellent fluorescent ability in detecting Fe3+, the ILs-POSS were immobilized on the testing paper to obtain the fluorescent paper shown in For the sake of intuitive observation of ILs-POSS in detecting Fe3+ aqueous solution. This phenomenon suggested that the three ILs-POSS reported were equipped with the potential ability to be employed as the fluorescent sensors in the field of detecting metal ions. These three ILs-POSS were distinct from other traditional ionic liquids. Firstly, it was more in accordance with the concept of “green chemistry” to adopt the approach of the thiol-ene “click” reaction, which does not consist of metal catalysts; secondly, the introduction of an Si atom into the product structures was beneficial to the enhancement of fluorescent intensity; thirdly, with POSS as the core of the structure, the application temperature range of the ILs-POSS was expanded.It is noteworthy that fluorescence was quenched after the testing papers were immersed in the Fe3+ of the three ILs-POSS, and the results demonstrated that the ILs-POSS performed excellent fluorescent sensibilities in detecting Fe3+ and have great potential to act as the fluorescent sensors in the field of detecting metal ions. In conclusion, this report described the synthesis of the novel ILs-POSS through thiol-ene “click” reaction and provided a potential application as fluorescent sensors. It is expected that more and more functionalized ILs-POSS can be produced via green chemistry reaction and applied as practical sensors in the future.All in all, the three ILs-POSS were synthesized in high yields through thiol-ene “click” reaction and characterized by comprehensive measurements. The ILs-POSS reported in this paper exhibited excellent thermal stabilities and low glass transition temperatures profiting from the highly structured POSS cage. Furthermore, the ILs-POSS presented spherical vesicle structures in selected solvents due to the unique amphiphilic nature and the strong electrostatic interactions among the molecules. Additionally, the fluorescent intensity of the ILs-POSS also performed excellently, not only owing to the imidazole ring, but also to the Si→S coordination bond. Based on the above data, we found the application in detecting Fe


The present paper focused on the investigation of the effectiveness of using various chemical admixtures and their effect on the strength and deformability of the reinforced spun concrete members—the supporting poles of the overhead power transmission lines—under the unfavorable long-term combined action of the aggressive salt-saturated groundwater and the temperature changes. According to the long-term experimental program, 96 prismatic spun concrete specimens were subjected to multi-cycle (25-50-75 cycles) processing under the combined aggressive environmental conditions. It has been found that chemical admixtures which decrease the initial water-cement ratio produce a considerable positive effect on the mechanical properties of spun concrete used in hot and arid climates and exposed to physical salt attack (PSA). Superplasticizers decrease the initial water-cement ratio the most, and, due to a unique concrete compaction method used, they produce the most homogeneous and dense concrete structure. They can be recommended as most effective in increasing the durability of spun concrete used under the above-mentioned aggressive environmental conditions. The wide application of reinforced concrete structures in engineering leads to very different operating conditions, which are often unfavorable to concrete durability. In general, the durability of concrete depends on its resistance under the physical, chemical, or biological actions of natural or artificial origin. Concrete durability is affected by a number of factors: the quality of the concrete components , the degree of concrete compaction, residual water-cement ratio (W/C), conditions of the concrete hardening, alternate wetting and drying conditions, bacterial corrosion, the attacks of various chemicals , seawater and brine exposure, calcium leaching, freezing and thawing, carbonation, etc. Under unfavorable operating conditions, the structural changes of the already hardened concrete stone, which significantly decrease the durability of concrete structures, occurs.General requirements to the durability of concrete and reinforced concrete structures are regulated by local design codes ,2,3. HowIn real service-life conditions, the concrete of structures is subjected, in most cases, not only to one  but also to several aggressive attacks. In some cases, the joint action of several unfavorable factors at the same time may cause a more destructive effect than only the combined defects, occurring when these factors act separately. In other cases, a simultaneous action of several types of aggressive factors may lead to the gradual destruction of concrete structures, compared to the cases of a separate action of these factors. It means that the investigation of durability of concrete in the aggressive environment has to be complex in character.The subject analyzed, i.e., spun concrete of the supporting poles of overhead power lines, in hot and arid climates is subjected not only to a single unfavorable action of temperature changes during the day-night time (up to 50–60 °C) and to the action of the aggressive groundwater, saturated with various kinds of salts, but also to the infiltration of water, saturated with salts, in concrete of the structures due to wind pressure . TherefoAs rightly observed by O.E. Gjorv ,5 and A.Focusing on the physical salts attack (PSA) on the reinforced concrete structures, dual penetration of salts into concrete or their contact with it in the areas of various climates may be observed. The first type of contact is external and appears in the colder climate zones, where salt is used as a means against icing up, in particular, for sprinkling the road surface with salt in winter. Another contact type can be observed in the warmer climate zones where the effect of salts is produced by the infiltration of salts dissolved in the groundwater and affects the concrete elements which are in contact with the soil. The present paper analyzed the supporting poles of the overhead power lines, used in the zones of dry and arid climate. Such climatic conditions occur, for example, in Asia, North Africa, and in some states of the USA. In these climatic zones, the considered negative salts’ effect is much more considerable because periodical temperature changes cause cyclic dehydration-hydration, which also accelerates the process of concrete destruction.Salts cause a number of negative effects in contact with concrete. They decrease the concrete pH, while the acidic reaction weakens the concrete structure (increasing the size of the pores), thereby decreasing its strength. As a hygroscopic material, salt attracts and retains water in the concrete pores and capillaries. This, in turn, produces the additional damaging crystallization pressure in the cases of salt crystallization or concrete freezing. Salt also accelerates concrete carbonization, thereby contributing to the reinforcement corrosion , not to Due to salt crystallization taking place in the concrete pores and capillaries, the crystals formed in the pores have the ability ‘to grow’ and, in time, cause damaging crystallization pressure in concrete pores. Therefore, their size and amount, strongly depending on water-cement ratio and the technology of concrete production and the time of the salt action (the number of wetting-drying cycles) are the main influencing factors used in assessing the damaging effect of salt on concrete. For this reason, some researchers recommend the maximum W/C ratio of 0.40–0.45 ,13,14.It should be noted that the presence of salt in the solution improves the structure of concrete in the initial period of action, while the negative effects related to damaging crystallization pressure are noticeable only after the prolonged action of cyclic wetting and drying (CWD). The crystallization pressure is caused by the repulsive forces acting between the growing salt crystal in the CWD process and the concrete pore wall.Currently, there are no common standard methods for testing the concrete resistance to PSA . Due to Apart from PSA, the second factor affecting the long-term strength of concrete is the operating temperature. The temperature accelerates not only the process of concrete paste hardening but also a whole number of physical-chemical processes taking place in the hardened concrete stone. For example, it accelerates the process of hardening and the reaction of alkaline compounds. This allows us to assume that alkali-aggregate reactions and the connected development of cracks and destruction are more intense and harmful in hot and arid regions. Only in more arid regions concrete might crack slightly less if it does not come in the direct contact with water. However, numerous cycling of dehydration and rehydration of the salts caused by temperature cycling accelerates the deterioration of concrete ,21,22,23A general and comprehensive literature review based on the effect of the elevated temperature on concrete materials and structures is presented in Reference . The detAlthough there are many papers about concrete durability and the related research about various aggressive actions ,21,22,23residual than those in regular vibrated concrete [Speaking about spun concrete products (including the supporting poles of overhead power lines), it should be mentioned that their production technology is specific, which results in the different concrete structure and texture and a smaller value of the residual water-cement ratio (W/C)concrete . The perconcrete .One of the effective measures to improve the durability of concrete is using water-soluble chemical admixtures ,27,28. AA series of previous papers by the authors analyzed the influence of chemical admixtures on the reinforced spun concrete elements-supporting poles of the overhead power transmission lines . The preAccording to the program of the present studies, 84 spun concrete specimens of annular cross section with the external diameter of 560 mm and the wall thickness of 50 to 95 mm were made at the factory conditions. The spun specimens were made of concrete mixes based on the binders and aggregates currently used at the considered factory. Portland slag cement with the compressive strength of 40 MPa was used as a binder. Its basic physical and mechanical parameters of cement are given in Sand and crushed granite stone were used as fine and coarse aggregates for making the experimental specimens. The main data on the granulometric composition and physical-mechanical properties of the concrete mix aggregates are given in To select an effective chemical admixture for increasing the physical and mechanical properties of spun concrete and creating the effective prestressed reinforced spun concrete supports of overhead power transmission lines resistant to corrosion, three-fourths of the specimens were made by using various chemical admixtures, such as superplasticizers C-3 and ‘Dofen’ (C-4), as well as acetone-formaldehyde resin ACF-3M . It shouAccording to the case of using chemical admixtures in spun concrete described by the authors in the previous studies, the effective quantity of chemical admixtures C-3 and ‘Dofen’ is 1% of the cement mass, while the effective amount of resin ACF-3M is 0.15% of the cement mass in the concrete mixes . All admLow-slump concrete mixes were used for making the tubular spun concrete specimens. The composition of the concrete mixes made without using any chemical admixtures was similar to the composition of the concrete mixes used at the reinforced concrete factories for making the spun concrete supports of the overhead power transmission lines and ensuring the strength of spun concrete of 60 MPa. The compositions of the concrete mixes, including chemical admixtures, were chosen so that the slump of concrete cone of these mixes could correspond to the similar parameter of the workability of the concrete mix made without any admixtures. This was achieved by varying the water-cement ratio (W/C). The detailed composition of spun concrete mixes, including the activity of cement, granulometric composition of aggregates, and water-cement ratio, is presented in The tubular 550 mm high specimens were made by using a roller-type centrifuge for one-layer centrifuging. The metallic molds with the inner diameter of 560 mm and the length of 23,100 mm aimed at manufacturing spun concrete poles of the overhead power transmission lines were used. Special metallic diaphragms were used for forming the specimens of the specified height of 550 mm. The technological parameters of producing the experimental spun concrete elements are presented in A steel mold with the spun concrete was subjected to thermal treatment according to the following mode: 2 h (curing at the temperature of about +20 °C) plus 2 h (raising the temperature to +75 °C), plus 3 h (curing at the temperature of + 75 ± 5 °C), and plus 2 h (lowering the temperature). It corresponds to the mode of thermal treatment of the reinforced spun concrete poles of overhead power transmission lines. Thermal treatment of spun concrete was performed in the induction chamber, where the reinforced concrete elements were heated by heating the metal mold and the reinforcement in the electromagnetic field.To check the strength of concrete from the initial concrete mix, simultaneously with the tubular spun specimens, the vibrated concrete cubes with the rib size of 10 cm and spun prisms were made. The latter elements were made with special attachments attached to the steel molds.In a single metal mold forty-two 550 mm high and of 50 to 95 mm thick spun concrete specimens of annular cross section were produced. Four various types of concrete mixes, including chemical admixtures and admixture free see  were cenA part of specimens of annular cross section were cut into prisms-segments , with onIn general, 96 prisms were cut out from the spun elements of annular cross section (12 elements of annular cross section were cut) for the present experiment.In real ambient conditions concrete in reinforced concrete structures is usually exposed to more than one aggressive attack .In some cases, the simultaneous action of various aggressive factors can result in slower destruction of a concrete structure than that observed in the case of their individual action.In other cases, the simultaneous action of several harmful factors on concrete results in a more destructive effect than that of the summed defects observed in concrete under the individual action of these factors.The total double effect of these attacks may occur:Thus, the study of concrete durability in harmful conditions should always be complex. The research should be made in several aspects: in the direction of concrete resistance to the action of the particular types of aggressive environment and to its resistance to the complex simultaneous action of several harmful factors.It is well-known that spun concrete, particularly the concrete in reinforced spun concrete poles of the supports of the overhead power lines, working in the countries with hot and dry climate, is subjected to great changes in the day and night air temperature, as well as to the aggressive action of the groundwater. Therefore, the present study is focused on testing the resistance of spun concrete to these two aggressive actions, also including the complex effect.As mentioned above, the complex effect, in particular, may be ambiguous. Therefore, for complex testing of the durability of spun concrete used in hot and arid climate and subjected to the aggressive salty groundwater, the authors developed a special technique for quickly determining the corrosion resistance of spun concrete, which corresponds best to the natural aggressive environment, where the reinforced spun concrete structures, in particular, the supporting poles of overhead power transmission lines are exposed. The technique involves the alternating processes of wetting spun specimens in the water or a salt solution and drying them in the air.The alternating processes of drying the specimens in the ambient air for 8 h at the temperature of 100 °C and their wetting in water for 8 h at the temperature of 20–25 °C.The alternating processes of drying the specimens in the ambient air for 8 h at the temperature of 100 °C and their wetting in the salt solution for 8 h at the temperature of 20–25 °C.According to this technique, the following modes of the aggressive environmental actions were used in testing spun concrete specimens:In order to eliminate completely the additional hydration of cement, occurring in wetting the concrete stone, the complex (combined) tests were performed with spun concrete of more than one year of age.The composition of the salt solution for creating the aggressive water environment in the laboratory conditions was chosen taking into consideration the results of the chemical analysis of the groundwater in the region of the service of the supporting poles of the overhead power transmission lines .It should be noted that, in real conditions, aggressive salt saturated groundwater is in contact only with one (outer) side of the concrete member. Therefore, in order to appropriately reflect a real one-sided action of the salt solution in the laboratory conditions, both ends of the prismatic specimens, as well as their lateral surfaces , were waterproofed before testing with 5 coats of polyvinyl acetate (PVA) glue. Then, the specimens were submerged in the salt solution or water  and held there for about 24 h. The wetting process of the specimens took place in two specially equipped containers with water or the salt solution, respectively.The specimens were dried in a specially equipped concrete drying chamber. The investigation of the resistance of spun concrete to various types of the aggressive environmental actions was performed in three stages after 25, 50, or 75 cycles of the wetting and drying, respectively.Two prisms were kept as control specimens under the conditions of the normal ambient temperature and humidity for evaluating the level of the impact of the two considered aggressive effects on the mechanical properties of spun concrete. The distribution of prismatic specimens, depending on the testing objectives, is presented in When the specified number of the cycles of the alternate wetting and drying of spun concrete was completed, the main and control prismatic specimens were subjected to the short-term axial compression in the dry conditions.To achieve more uniform inclusion of the cross section of specimens into the resistance under loading, their facing parts were inserted into special metallic casings by using the cement mortar. The specimens were tested by using a hydraulic press with the power of 5000 kN. The specimens were centered until the loads reached 25–30% of the maximal loads. For this purpose, the clock type mechanical indicators were used for measure linear strains. The loads were applied in steps amounted to 5–7% of the expected maximum strains. The tests lasted for 30–40 min, while the axial and transverse concrete strains of the prismatic specimens were measured by the strain gauges with a measuring base of 50 mm. The prism specimens were subjected to the action of the short-term axial compressive load. The specimens prepared for testing are presented in The major characteristics of the cross section and the results of testing under short-term axial compression of the prismatic specimens , subjected or not subjected (the control specimens) to the aggressive action, by different number of CWD, are presented in The statistical analysis of the experimental data has shown that the variation coefficient of the compressive strength of the control spun concrete prisms soaked for various numbers of cycles in the water or a salt solution and dried in the air was not higher than 9% for each series and the initial modulus of elasticity was not higher than 13%. Though the number of the test specimens in each series was only three (due to experiment complexity), the above statistical indicator shows that the experiment was performed sufficiently accurately and the obtained results were reliable.α and β. These coefficients show the degree of retaining of the initial mechanical properties of concrete under the influence of the particular aggressive environment. The resistance coefficient is determined by the ratio between the mechanical properties of concrete subjected and not subjected to the action of the aggressive environment. The coefficients α and β were determined based on two major characteristics of the mechanical properties of concrete in compression, i.e., prismatic compressive strength cf and the modulus of elasticity E, respectively.The resistance of spun concrete to the action of the aggressive environment was assessed by the dimensionless coefficients of resistance Taking into consideration that various chemical admixtures were used in making the spun concrete specimens, for which testing for durability various aggressive environmental actions were employed, the three-digit indices were introduced for considering the testing specimens. Each of them indicates the type of the chemical admixture and the temperature mode, as well as the mode of wetting and drying the main specimens used.1.Acetone-formaldehyde resin ACF-ЗM;2.Superplasticizer ‘Dofen’;3.Superplasticizer C-3;0.The admixture-free concrete mix.The first index digit in the three-digit indices of the mechanical properties of spun concrete indicates the type of the chemical admixture used as follows:1.Drying the specimens in the air at the temperature of 100–105 °C;0.Storing the specimens in the air at the temperature of 18–22 °C.The second index digit shows the ambient temperature conditions as follows:1.Water of normal temperature (20–25 °C);2.Salt solution of normal temperature (20–25 °C);0.The air of normal humidity (the control specimens) and temperature (20–25 °C).The third index digit shows the environmental conditions in the process of wetting the main specimens and curing the control specimens:c,i,f1,1 and cEi,1,1, denote the prismatic compressive strength and the initial modulus of elasticity of spun concrete subjected to the cyclic actions of drying in the air under the temperature of 100–105 °C and wetting in the water of 20–25 °C; c,if,0,0 and c,iE,0,0 indicate the prismatic compressive strength and the initial modulus of elasticity of spun concrete cured in the air of normal ambient temperature and humidity.The resistance of spun concrete under the temperature changes was evaluated by the dimensionless coefficients as follows:c,if,1,2 and c,iE,1,2 indicate the prismatic compressive strength and the initial modulus of elasticity of spun concrete subjected to the cyclic actions of drying in the air of 100–105 °C and wetting in the salt solution at the temperature of 20–25 °C.As mentioned above, great attention should be paid to studying the resistance of concrete used in the extreme environmental conditions to the combined effect of the aggressive action of various conditions, for example, the salt solution and temperature variations (as in the present study). The considered resistance of concrete was described by the coefficients:Using chemical admixtures in the concrete mix increases the cost of production; therefore, the efficiency of their use in concrete mixes should be determined preliminarily.γ assessing the ratio between the values of the average prismatic compressive strength of the hardened concrete made with and without the admixtures is suggested:The effectiveness criterion (coefficient of effectiveness) In calculating this coefficient, the prismatic compressive strength of concrete stored for the same time under the same conditions  were compared.tα and tβ, referring to 25, 50, and 75 cycles of alternate drying in the air and wetting in the water, a considerable negative effect of temperature changes on the mechanical properties and durability of spun concrete can be observed  and t,cβ according to (4), given in The data obtained in testing spun concrete, subjected to 25, 50, and 75 cycles of alternate drying in the air and wetting in the salt solution, have shown that admixtures actually produce the same positive effect on the considered indicator of spun concrete resistance. It can only be mentioned that, in the considered case, the admixtures C-3 and ‘Dofen’ appeared to be most effective. This is shown by the experimental values of the coefficients of resistance Comparing the data given in the histograms in In the case of a complex effect of a salt solution and temperature changes, the negative effect of the latter, shown by the formation of micro cracks in concrete, is smoothed by a positive effect of new formations of salt crystals in micro cracks and pores on the strength and deformability of concrete.Thus, in the case of the above complex aggressive effect of the environment, the corrosion of concrete characterized by the crystallization of salts in the concrete pores with the consequent pressure of the edges of the growing crystals on the walls of the pores, in the considered case (after 50 CWD cycles) produced a positive rather than a negative effect on the mechanical properties of ordinary spun concrete. This means that the corrosion of the third type ‘cured’ the damaged structure of ordinary spun concrete caused by cyclic temperature changes.The most detailed analysis of stresses caused by salt crystallization was performed by G. W. Scherer ,30. Thern > 50), when the process of micro cracks’ formation in concrete caused by the cyclic temperature changes actually stops, a positive effect of the corrosion of the third type on the strength and deformability of concrete (by curing the defects) turns into a negative effect because the pressure on the walls of the pores and micro cracks exerted by the edges of the growing crystals can be observed. This was confirmed by the results of the tests performed by using prisms when, after 75 cycles of their wetting in the salt solution, the coefficient of resistance t,cα decreased considerably.However, in the case of a larger amount of the CWD cycles  and t,cβ based on (4) since both these influencing factors (temperature changes and concrete corrosion of the third type) are interrelated.Based on the above mentioned facts, it can be concluded that corrosion resistance of spun concrete under the complex aggressive effect of the salt solution and temperature changes can hardly be determined only by the coefficients The use of chemical admixtures in making the objects of spun and vibrated concrete has been discussed in one of the papers , where, As a result, a considerable economy of cement and a shorter time of curing the concrete can be obtained, which, in turn, allows for the economy of power resources, faster reuse of metal molds and smaller labor expenditure at the plants of reinforced concrete structures’ production . In the This paper presents the research results, allowing us to summarize the effectiveness of using chemical admixtures in spun concrete at the age of up to 1.5 years, as well as in concrete soaked in the water or the salt solution for 25, 50, or 75 cycles and dried in the air at 100 °C, and their effect on its durability.n = 25), a year (n = 50) or 1.5 years (n = 75) hardened under normal ambient temperature and humidity were decreasing and seemed to depend on the initial water-cement ratio of the concrete mix  the strength increases by ~16% per year, while, for concrete with admixtures C-3 and ‘Dofen’, the strength increases by ~2–5% per 1.5 years.Considering the data given in These relationships are similar to those obtained for spun concrete mixes with chemical admixtures and for spun concrete soaked in water or a salt solution  and drieThe compression stress of these types of concrete after their subjection to the action of the aggressive environment for 75 cycles and reaching the age of 1.5 years exceeds the stress of concrete without any admixtures by 40–50% when admixtures C-3 and ‘Dofen’ are used and only by ~10% when the admixture ACF-3M is used.When turned into the economic effect, the effective service time of spun concrete supporting poles of the overhead electric power transmission lines together with the repair and replacement of the poles, the sums of milliards of euros could be obtained. The producing cost of a single supporting pole of 110 kV and its mounting in the overhead electric power transmission line in Lithuania is over 4.5 thousand Euros.It has been determined that, after 25, 50, and 75 cycles of concrete wetting in the water and drying in the air, the temperature gradient (80 °C) produce a considerable negative effect on the mechanical properties of spun concrete. Depending on the number of the wetting-drying cycles, the compression strength of concrete without admixtures is decreased by 20–30%, while its modulus of elasticity is decreased by 30–40%. However, the compression strength of spun concrete with superplasticizers C-3 and Dofen, which reduce the initial water-cement ratio, is decreased by 10–15%, while its modulus of elasticity is decreased by 20–25%. The compression strength and the modulus of elasticity of spun concrete with the ACF-3M admixture, which only slightly reduces the initial water-cement ratio, are decreased to a greater extent–by 15–20% and 25–30%, respectively.It has been found that under the complex action of temperature changes and a salt solution, complex and important processes are taking place in the structure of spun concrete. First, the fading process of the concrete structure’s destruction caused by the cyclic temperature changes takes place. Second, the salt solution contributes to the improvement of the concrete structure in the initial period of the investigated environmental effect. Under the action of a long-term complex effect of temperature changes and the salt solution, the positive effect of concrete corrosion of the third type turns into a negative effect. After 75 cycles of the complex effect of temperature and the salt solution, the compression strength of spun concrete without admixtures decreased by 35%, while the modulus of elasticity–by 40%. For concrete with admixtures, these mechanical properties decreased to a lesser extent, by 25–35%.The coefficients of effectiveness (5) describing the effectiveness and economic use of chemical admixtures, decreasing the initial water-cement ratio in the concrete mix, show that the considered admixtures improve the mechanical properties of spun concrete used in dry and hot climatic conditions by up to 1.5 times.


In this study, recycled aggregate concrete (RAC) modified with polypropylene fiber (PP) and air-entraining agent (AGA) was prepared, and the effects of PP and AGA on the static  and dynamic properties (dynamic modulus of elasticity and damping ratio) of RAC were investigated. The experimental results showed that the addition of an AGA and PP had a favorable effect on the damping ratio of the concrete, however, the addition of the AGA had a slightly negative effect on the mechanical performance of the concrete. The AGA and PP contents required to achieve the optimum damping ratio of the concrete with the least reduction in the mechanical performance were 0.02% and 0.10%, respectively. Furthermore, the addition of AGA was more effective than that of PP in improving the damping property of the concrete. Concrete is the most common construction material and has been extensively used in buildings, bridges, and dams owing to the advantages of its low cost, abundant raw materials, high strength, and excellent durability ,2. AggreRecycled concrete aggregate (RCA) is manufactured from abandoned concrete blocks by a series of processes, including washing, crushing, and grading. RCA is a renewable resource and can be used to alleviate environment pollution ,11. StudDynamic characteristics govern the intrinsic properties of a material and can reflect the behavior of a material under dynamic loading . Such chStudies have suggested that due to its high tensile strain, a fiber polymer, as an additive, can contribute to improving the performance of concrete ,7,21,22.In this study, for the first time, RAC was incorporated with the advantage of PP as well as the high damping characteristic of AGA. The damping properties of RAC at various PP and AGA contents were compared with those of the reference concrete. Our results provide a deep understanding of the dynamic behavior of RAC modified with PP and AGA and potentially serve as an effective tool for designing concrete with excellent damping property.The cementitious materials used were ordinary Portland cement (P·O 42.5) and fly ash (FA). The cement was purchased from Shaanxi Qinling Cement Co., Ltd. , and the FA was purchased from Shenmu County Huatai Clean Coal Technology Development Co., Ltd. . The fine aggregate used was river sand (RS) with a fineness modulus of 2.60 (medium sand); it has water absorption of 1.15% and specific gravity of 2.45. The coarse aggregates used were NCA (broken granite gravel) and RCA (laboratory waste concrete block) and with continuous grading. The maximum size of the coarse aggregates was 25 mm. PP with a length of 12 mm was used to improve the damping property of RAC. Polycarboxylate superplasticizer (SP) with a water reduction ratio of 30% and solid content of 35% was used in this study. An AGA with a specific density of 1.02% was used to enhance the damping property of the concrete.3. The mixing water consisted of two parts: water consumption of ordinary concrete mix design and additional water. It should be noted that the additional water did not change the effective water-to-binder ratio of the mixture. Nine different mixtures of RAC modified with AGA (wt.%) and PP (V%) were prepared. For testing the compressive strength, Young’s modulus, and splitting tensile strength, 150 mm × 150 mm × 150 mm cubic molds, 100 mm × 100 mm × 400 mm prism, and 150 mm × 150 mm × 300 mm prism cubic molds were used, respectively, according to GB/T 50081-2002 . The tesdE, W, L, f, and α represent the dynamic modulus of elasticity of RAC (MPa), weight of sample (kg), length of test sample (mm), transverse frequency of the specimen (Hz), and the side length of square cross-section sample (mm), respectively.The dynamic modulus of elasticity of the concrete was determined by the resonant frequent method in accordance with GB/T 50082-2009 . It was 2/s) graphs, as shown in 0) was obtained [ξ, f1, and f2 represent the damping ratio of concrete (%), frequency corresponding to an amplitude of f0 /√2 (Hz), and the resonant frequency of concrete (Hz), respectively.The damping ratio of concrete was evaluated by the vibration of a free-free beam. A pulse hardware/software vibration analysis system (Brüel and Kjær) was utilized to record the acceleration response signals as time magnitude and hammer force, as shown in obtained . The halobtained . All speFurther, a large number of micro-cracks and voids exist in the old cement mortar and ITZs of RAC, as seen in The compressive strength of RAC slightly decreased by 1.15% (50RAC-A1) and 3.54% (50RAC-A2) when the AGA content was below 0.02%, but was sharply reduced to 10.95% (50RAC-A3) for the mixture containing 0.03% AGA as compared to that of the 50RAC sample after 28 days of curing. This could be attributed to the increment of porosity due to the introduction of AGA in concrete.The compressive strength of the RAC decreased by 18.03% (50RAC-P1), 3.15% (50RAC-P2), and 22.89% (50RAC-P3) than that of 50RAC after 28 days of curing. The PP-reinforced RAC consisted of six phases: original aggregate, natural aggregate, cement mortar (new cement mortar and old cement mortar), new ITZ (between the NCA and new cement mortar), old ITZ (between the NCA and old cement mortar), and ITZ between the fiber and cement mortar . A largeThe Young’s modulus of the RAC decreases by 3.77% and 41.74% for RCA with replacement percentage of 50% and 100%, respectively, as compared to that of the reference concrete. Furthermore, the Young’s modulus of the RAC decreased with increasing AGA content. A slightly decreasing trend is observed when the AGA content is less than 0.02%. However, when the AGA content is higher than 0.02%, the Young’s modulus of the specimens (50RAC-A3) exhibit a significant reduction. Previous studies have indicated that the properties of aggregates significantly affect the Young’s modulus of concrete ,4. The rFurthermore, the splitting tensile strength of concrete decreases by 1.57% (50RAC-A1), 2.42% (50RAC-A2), and 13.53% (50RAC-A3) as compared to that of the 50RAC samples. Therefore, a similar conclusion as that from the compressive strength test can be drawn, i.e., a higher dose of AGA adversely affects the splitting tensile property of the RACs regardless of the replacement ratio of the RCA. While a slight increment was found for the specimen containing PP, the splitting tensile strength of concrete increased by 3.85% (50RAC-P1), 4.42% (50RAC-P2), and 3.27% (50RAC-P3). Similar conclusions have been reported by earlier studies ,31.The dynamic behavior, i.e., the dynamic modulus of elasticity and damping ratio of the reference concrete and the RAC modified with AGA and PP, is shown in It is evident from The dynamic modulus of elasticity of the samples 50RAC-A1, 50RAC-A2, and 50RAC-A3 decreases by 1.60%, 4.34%, and 13.65%, respectively, as compared to that of 50RAC specimen. It is clear seen that the dynamic modulus of elasticity decreases with the increase in the replacement percentage of RCA and the AGA content. The dynamic modulus of elasticity of the samples 50RAC-P1, 50RAC-P2, and 50RAC-P3 decreases by 22.51%, 4.62%, and 29.64%, respectively, indicating that the addition of PP can significantly reduce the dynamic modulus of elasticity of RAC with the exception for concrete with 0.50% PP.The damping ratio of concrete exhibits a sharply increasing trend with the increase in the replacement percentage of RCA, as seen in Previous reports have indicated that the indentation modulus of new cement mortar is 1.18 times that of new ITZ, while the indentation modulus of the old cement mortar is approximately 1.33 times higher than that of the old ITZ in the RAC , which iThe damping ratio of RAC increases with the increase in the AGA content. This increasing trend is more obvious when the AGA content is above 0.02%. The central function of the AGA is to introduce several air bubbles and pores into the concrete, which plays a vital role in flexible cushioning bag when the structure is subjected to external vibration, as shown in The damping ratio of the samples 50RAC-P1, 50RAC-P2, and 50RAC-P3 increases by 3.18%, 0.66%, and 5.26%, respectively, as compared to that of the 50RAC specimen after 28 days of curing. This can be attributed to the significant gap between the micro-hardness of ITZs , which increases the energy dissipation of RAC due to the sliding between the ITZs [The RCA had a marginal effect on the mechanical properties of RAC with a replacement aggregate percentage of 50% (reduced by approximately 5%). However, the mechanical properties of the RAC with 100% replacement aggregate were significantly affected (approximately decreased by 40%) than those of the reference concrete.The addition of both AGA and PP adversely affected the mechanical properties of the concrete, and the effect of PP addition on the reduction of the mechanical properties of RAC was stronger than that of AGA addition. The compressive strength and Young’s modulus reduced slightly when the AGA content was below 0.02%.The addition of both AGA and PP favorably affected the damping property of the concrete, and the addition of AGA was more effective than that of PP in increasing the damping ratio of the RAC. Furthermore, the AGA and PP contents to achieve the optimum dynamic property of the concrete with the least reduction in the mechanical performance were determined to be 0.02% and 0.10%, respectively.We prepared RAC containing PP and AGA and evaluated their damping properties and mechanical performance at various AGA and PP contents. The important results of this study are summarized as follows:


Advanced colorectal adenocarcinoma (CRAC), featured by distinctive histopathological appearance, distant organ metastasis, acquired chemoresistance, and tumorigenic stemness is a group of heterogeneous cancers with unique genetic signatures and malignant phenotypes. Treatment of CRAC is a daunting task for oncologists. Currently, various strategies including molecular targeting using therapeutic monoclonal antibodies, small molecule kinase inhibitors and immunoregulatory checkpoint therapy have been applied to combat this deadly disease. However, these therapeutic modalities and approaches achieve only limited success. Thus, there is a pharmaceutical need to discover new targets and develop novel therapeutics for CRAC therapy. MET and RON receptor tyrosine kinases have been implicated in CRAC pathogenesis. Clinical studies have revealed that aberrant MET and/or RON expression and signaling are critical in regulating CRAC progression and malignant phenotypes. Increased MET and/or RON expression also has prognostic value for CRAC progression and patient survival. These features provide the rationale to target MET and RON for clinical CRAC intervention. At present, the use of small molecule kinase inhibitors targeting MET for CRAC treatment has achieved significant progress with several approvals for clinical application. Nevertheless, antibody-based biotherapeutics, although under clinical trials for more than 8 years, have made very little progress. In this review, we discuss the importance of MET and/or RON in CRAC tumorigenesis and development of anti-MET, anti-RON, and MET and RON-dual targeting antibody-drug conjugates for clinical application. The findings from both preclinical studies and clinical trials highlight the potential of this novel type of biotherapeutics for CRAC therapy in the future. Advanced colorectal adenocarcinoma (CRAC), defined by its histopathological appearances, metastatic dissemination, and acquired chemoresistance, is a distinctive, heterogenic and aggressive cancer , 2. DuriNon-surgical treatment of CRAC aimed at prolonging survival is a serious clinical challenge. Except first-line chemotherapies, molecularly targeted and immunoregulatory approaches have been applied with clinical benefits , 9, 10. For the last 30 years, roles of MET and RON in CRAC have been established , 12. CurGenetic alterations in MET and RON genes are characterized by activating mutation, gene amplification, and/or aberrant exon splicing Fig.  12, 28,,28, 29. Pathogenesis of MET and/or RON in CRAC is characterized by phenotypic plasticity known as epithelial to mesenchymal transition (EMT), featuring increased survival, invasive growth, acquired chemoresistance, and tumorigenic stemness Fig.  11, 12,, 30–38. Clinical studies using immunohistochemical (IHC) staining provide insight into the status of MET and/or RON expression in primary CRAC samples. In the majority of IHC studies using primary CRAC samples, high frequencies of MET and/or RON expression are documented , 44–54. Clinically, increased expression of MET, RON, or both receptors has been shown to have prognostic value , 44–54. First, MET and RON are highly and preferentially expressed in CRAC cells but minimal in their corresponding normal epithelial tissues . I. I57]. IPhase I clinical trials of telisotuzumab vedotin, that ended in the middle of 2018, show promising results for this ADC . Among 4BSHR-A1403: This ADC is formed by humanized anti-MET mAb HTI-1066  with payload SHR152852 using a non-cleavable linker  and a relatively long terminal half-life (t½: 6.1 day) [85 indicating low systemic exposure of the free toxin to tissues.6.1 day) , 60, 85.in vitro strongly causes cell cycle arrest and inhibits proliferation of cancer cells from gastric, lung, breast, prostate, renal, and hepatic tissues [in vivo has been determined in several xenograft tumor models using cancer cell lines derived from liver, lung, and gastric tissues with different malignant and chemoresistant statuses and of hepatocellular carcinoma (HCC) PDX models  to PBD toxin-linker tesirine  [ine Fig. ; Table 1Table 1) . TR1801 Table 1) . P3D12 aTable 1) . ModificTable 1) . The PBDTable 1) . The useTable 1) . These fin vitro is highly potent against cancer cells expressing high levels of MET  with or without MET gene amplification (Table 1). Also, CRAC cell lines expressing low to moderate levels of MET  are sensitive to TR1801-ADC [in vitro studies that among all anti-MET ACDs tested, TR1801-ADC is the most potent in killing cancer cells expressing variable levels of MET.TR1801-ADC is homogeneous with an average DAR of ~ 2.0 . Toxic s1801-ADC . In a co1801-ADC , 86. It ex vivo 3D tumoroid and xenograft tumor models including primary PDXs have been applied to validate TR1801-ADC Antibodies selected for ADC development: Currently, two anti-RON mAbs, Zt/g4 and PCM5B14, have been selected, resulting in Zt/g4- and PCM5B14-based ADCs for potential clinical evaluation Cytotoxicity of anti-RON ADCs in CRAC cellular models: Various CRAC cell lines with different subtypes, malignant status, drug sensitivity, and levels of RON expression have been tested for their response to anti-RON ADCs [RON ADCs –63. BothRON ADCs –81. The (C)Therapeutic efficacy of anti-RON ADCs in CRAC xenograft models: Studies from animal models have proven the efficacy of both Zt/g4- and PCM5B14-based anti-RON ADCs in inhibition and/or eradication of CRAC cell-derived xenograft tumors Pharmacokinetic and toxicological Features of Anti-RON ADCs: Both Zt/g4 and PCM5B14 based ADCs, formed either by noncleavable or by cleavable linkers, are stable in human plasma up to 30 days with less than 4.0% of payloads dissociated from the antibody [in vivo [antibody , 79–81. [in vivo –63. The [in vivo . Zt/g4-M[in vivo . These oToxicological analysis in both mice and cynomolgus monkeys demonstrate that anti-RON ADCs are safe with manageable adverse activities , 79–81. (A) MET and RON dual targeting ADC: PCMdt-MMAE is the first dual targeting ADC specific to both MET and RON  range from 10 to 20 h dependent on cellular levels of MET and RON expression, which results in delivery of sufficient amounts of payload for cancer cell killing [Third, PCMbs-MR is suitable for conjugation with various payloads, including MMAE and DM-1, using either cleavable or noncleavable linkers. The resulting ADCs are stable in serum and have a favorable PK profile in mice [Finally, the fact that PCMbs-MR recognizes not only human MET and RON but also their monkey corresponding homologies make it suitable for using the monkey model to study the PK profile and toxicological activity of PCMdt-MMAE.RON Fig. ; Table 1or mouse . The duaor mouse , 78. Secin vitro meet pharmaceutical expectations in terms of its potency in killing CRAC cells. Flow cytometric analysis indicates that PCMdt-MMAE causes cell cycle arrest in the G2/M phase. This effect is observed as early as 12 h after ADC treatment and characterized by progressive reduction of the G1 phase and the accumulation of cells at the G2/M phase [50 values ranging from 1 to 15 nM. Analysis of cellular morphology and apoptotic markers has confirmed PCMdt-MMAE-induced CRAC cell death [The biological activities of PCMdt-MMAE /M phase . PCMdt-Mll death . The facFirst, in a comparative study using anti-MET ADC PCM-MET01-MMAE and anti-RON ADC PCM5B14-MMAE for comparison, PCMdt-MMAE on average reduces tumor volume up to 93%, decreases tumor weight up to 96%, and eradicates tumors up to 20%. The calculated TSC for PCMdt-MMAE is 0.35 mg/kg, similar to that for PCM-MET01-MMAE and PCM5B14-MMAE (0.51 mg/kg and 0.32 mg/kg. respectively) [Second, in a concentration-dependent experiment, PCMdt-MMAE at 1 mg/kg is sufficient to inhibit CRAC xenograft growth and prevent tumor regrowth for up to two weeks. Additional analysis confirms reduction of tumor weight ranging from 65–99% dependent on the dose of PCMdt-MMAE used. Also, PCMdt-MMAE at 3 to 10 mg/kg is capable of eliminating tumors at variable levels [Third, in tumors mediated by cancer cell lines from colon, lung, pancreas and breast, regardless of their metastatic and chemoresistant status, PCMdt-MMAE shows a broad anticancer activity leading to inhibition of all these xenografts. The inhibition by average tumor volume was 97% for CRAC HCT116, 86% for SCLCS H358, and 91% for pancreatic cancer BxPC-3 mediated tumors. More importantly, the effect of PCMdt-MMAE is long-lasting. At 10 mg/kg in a single dose injection schedule, PCMdt-MMAE inhibits xenograft tumor growth for almost four weeks, equivalent to a ~ 6 half-life cycle in vivo [Studies from mouse models prove the therapeutic effectiveness of PCMdt-MMAE Fig. F. This cctively) . These re levels . Thus, P in vivo . Thus, Pin vivo. It appears that the PK profile of PCMdt-MMAE in mice displays a two-compartment model, similar to other clinically approved ADCs such as T-DM1. Moreover, the PK profiles of PCMdt-MMAE between tumor-bearing and -nonbearing mice show no differences. Overall, data from tumor-bearing mice overlap with those from tumor-nonbearing mice with 95% prediction intervals [in vivo. In other words, tumors constitutively expressing MET and RON probably have very little effect on absorption, distribution, metabolism, and excretion of PCMdt-MMAE [The use of mouse models for the PK profiling provides insight into the dynamics of PCMdt-MMAE ntervals . AdditioMdt-MMAE . Nonethein vivo should not exceed 30 mg/kg limitation. Considering the average TSCs (0.35 mg/kg) of PCMdt-MMAE in xenograft models tested, the dose limitation judged by mouse bodyweight should be a valuable reference, together with toxicological studies in primates, for the use of PCMdt-MMAE in a first-in-human study in the future.Toxic activities of PCMdt-MMAE at therapeutic doses in mice appears to be safe with minimal impact on animal’s behavior or body weight. However, a single dose of PCMdt-MMAE at 30 mg/kg has a negative impact in mice highlighted by slight changes in mouse behavior and by moderate reduction in bodyweight for a short period . This im(B) MET and EGFR dual targeting ADC: At present, two dual targeting ADCs specific to both MET and EGFR, namely B10v5 × 225-H-vc-MMAE and B10v5 × 225-M-vc-MMAE, have been described (Table 50 values ranging from 0.4 to 1.0 nM/L [1.0 nM/L . UnfortuAberrant MET and RON expression and signaling are malignant features in CRAC with different behaviors and phenotypes. Altered expression of MET, RON and both receptors also have prognostic values for disease progression and patient survival. Establishment of MET and RON as therapeutic targets has led to the development of antibody-based biotherapeutics including ADCs for potential clinical application. Unlike MET-specific SMKIs that require cancer cell signaling addiction for growth and survival to show therapeutic activity, ADCs specifically deliver highly potent cytotoxic payloads for cancer cell killing and eradication. Currently, various ADCs targeting MET, RON, or both receptors are in preclinical development and some of them have advanced into clinical trials with promising results. Considering therapeutic superiorities with favorable pharmacological profiles and manageable adverse activities, ADCs targeting MET, RON, or both receptors hold the promise as an effective modality for CRAC treatment in the future. In this sense, the success of ADCs will depend on stratification of CRAC patients selected for clinical trials, suitability of optimized ADC dosing and schedule, and criteria for objective efficacy evaluation. Moreover, the advancements in IgG recombination technology, generation of versatile chemical likers, selection of suitable payloads for maximizing killing of cancer cells, and pharmaceutical improvements will lead to the development of new generations of ADCs in the near future for clinical CRAC application.