Peroxymonosulfate activation by CuMn-LDH for the degradation of bisphenol A: Effect, mechanism, and pathway.

The remediation of water contaminated with bisphenol A (BPA) has gained significant attention. In this study, a hydrothermal composite activator of Cu3Mn-LDH containing coexisting phases of cupric nitrate (Cu(NO3)2) and manganous nitrate (Mn(NO3)2) was synthesized. Advanced oxidation processes were employed as an effective approach for BPA degradation, utilizing Cu3Mn-LDH as the catalyst to activate peroxymonosulfate (PMS). The synthesis of the Cu3Mn-LDH material was characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). According to the characterization data and screening experiments, Cu3Mn-LDH was selected as the best experimental material. Cu3Mn-LDH exhibits remarkable catalytic ability with PMS, demonstrating good degradation efficiency of BPA under neutral and alkaline conditions. With a PMS dosage of 0.25 g·L-1 and Cu3Mn-LDH dosage of 0.10 g·L-1, 10 mg·L-1 BPA (approximately 17.5 µM) can be completely degraded within 40 min, of which the TOC removal reached 95%. The reactive oxygen species present in the reaction system were analyzed by quenching experiments and EPR. Results showed that sulfate free radicals (SO4•-), hydroxyl free radicals (•OH), superoxide free radicals (•O2-), and nonfree radical mono-oxygen were generated, while mono-oxygen played a key role in degrading BPA. Cu3Mn-LDH exhibits excellent reproducibility, as it can still completely degrade BPA even after four consecutive cycles. The degradation intermediates of BPA were detected by GCMS, and the possible degradation pathways were reasonably predicted. This experiment proposes a nonradical degradation mechanism for BPA and analyzes the degradation pathways. It provides a new perspective for the treatment of organic pollutants in water.

Development, comparison, and internal validation of prediction models to determine the visual prognosis of patients with open globe injuries using machine learning approaches.

INTRODUCTION: Open globe injuries (OGI) represent a main preventable reason for blindness and visual impairment, particularly in developing countries. The goal of this study is evaluating key variables affecting the prognosis of open globe injuries and validating internally and comparing different machine learning models to estimate final visual acuity. MATERIALS AND METHODS: We reviewed three hundred patients with open globe injuries receiving treatment at Khatam-Al-Anbia Hospital in Iran from 2020 to 2022. Age, sex, type of trauma, initial VA grade, relative afferent pupillary defect (RAPD), zone of trauma, traumatic cataract, traumatic optic neuropathy (TON), intraocular foreign body (IOFB), retinal detachment (RD), endophthalmitis, and ocular trauma score (OTS) grade were the input features. We calculated univariate and multivariate regression models to assess the association of different features with visual acuity (VA) outcomes. We predicted visual acuity using ten supervised machine learning algorithms including multinomial logistic regression (MLR), support vector machines (SVM), K-nearest neighbors (KNN), naïve bayes (NB), decision tree (DT), random forest (RF), bagging (BG), adaptive boosting (ADA), artificial neural networks (ANN), and extreme gradient boosting (XGB). Accuracy, positive predictive value (PPV), recall, F-score, brier score (BS), Matthew correlation coefficient (MCC), receiver operating characteristic (AUC-ROC), and calibration plot were used to assess how well machine learning algorithms performed in predicting the final VA. RESULTS: The artificial neural network (ANN) model had the best accuracy to predict the final VA. The sensitivity, F1 score, PPV, accuracy, and MCC of the ANN model were 0.81, 0.85, 0.89, 0.93, and 0.81, respectively. In addition, the estimated AUC-ROC and AUR-PRC of the ANN model for OGI patients were 0.96 and 0.91, respectively. The brier score and calibration log-loss for the ANN model was 0.201 and 0.232, respectively. CONCLUSION: As classic and ensemble ML models were compared, results shows that the ANN model was the best. As a result, the framework that has been presented may be regarded as a good substitute for predicting the final VA in OGI patients. Excellent predictive accuracy was shown by the open globe injury model developed in this study, which should be helpful to provide clinical advice to patients and making clinical decisions concerning the management of open globe injuries.

Tamoxifen induced maculopathy presenting like macular telangiectasia type 2 in a patient with breast cancer.

INTRODUCTION: Drug-induced crystalline maculopathy has been reported secondary to tamoxifen use for breast cancer treatment. It could be misdiagnosed as macular telangiectasia type 2 (MacTel type 2). CASE REPORT: A 56-year-old woman with a history of diabetes mellitus and breast cancer was referred to our clinic with painless, bilateral, gradual onset of central vision loss for several months. The fundus examination showed the macular pigmentary change in both eyes and a few refractile crystalline deposits in the parafoveal area in the left eye. However, the rest of the retina was normal in both eyes. MANAGEMENT AND OUTCOME: With the diagnosis of tamoxifen-induced maculopathy, the drug was discontinued and supplementary treatment was started. DISCUSSION: In this report, patient medical and drug history was an important and powerful measure. Due to the side effects of long-term use of tamoxifen, we need further studies on the need for retinal screening in these patients.

A comprehensive review on pollution status and associated health risk assessment of human exposure to selected heavy metals in road dust across different cities of the world.

In order to expound on the present situation and potential risk of road dust heavy metals in major cities, a total of 114 literatures mainly over the past two decades, involving more than 5000 sampling sites in 61 cities of 21 countries, were screened through the collection and analysis of research papers. The concentration, sources, distribution, health risk, sample collection, and analytical methods of heavy metal research on road dust in cities around the world are summarized. The results show that Cd, Zn, and Cu in many urban road dusts in the world are higher than the grade II of the Chinese maximum allowable concentration of potentially toxic elements in the soil. Geo-accumulation index values show that Pb > Cd > Zn > Cu had the highest contamination levels. Hazard index assessment indicates Pb and Cr had the highest potential health risk, especially for children in which ingestion was found as the main exposure pathway. Moreover, through comparative analysis, it is found that some pollutants are higher in developed and industrialized cities and transport (53%) followed by industrial emissions (35%) provide the major contributions to the sources of heavy metals.

Evaluation of the Effect of Religious Fasting on Retinal Vessel Density and Retinal Thickness Using Optical Coherence Tomography Angiography.

We conducted this study to assess the effect of religious fasting on intraocular pressure (IOP) as well as retinal parameters and retinal thickness during Ramadan using optical coherence tomography angiography (OCTA) performed on a spectral domain device. All the participants ate a pre-dawn meal and drink, and then fasted for at least 15 hours. We assessed a total of 61 eyes from 31 healthy volunteers with a mean age of 32.87 ± 8.07. A significant decrease was found in the median IOP after fasting at 10.00 mmHg in comparison with the pre-fasting value of 12.00 mmHg (p < .0001). Retinal peri-papillary capillary (RPC) whole image, RPC inside disk, and RPC mean values showed significant decreases after fasting (p = .011, .012, and .032 respectively). RPC whole vessel density (VD), RPC inside VD, and RPC VD mean values also showed significant decreases after fasting period (p = .025, <.0001, and .003, respectively). Religious fasting during the warm season could decrease IOP. It could also reduce the blood flow of the retina, specifically the macula, and the retinal peri-papillary VD.

Activities and polymorphisms of MMP-2 and MMP-9, smoking, diabetes and risk of prostate cancer.

Matrix metalloproteinases (MMPs) are a group of zinc dependent enzymes that are involved in tumor cell invasion and metastasis. The role of MMP-2 and -9 genetic polymorphism in different malignancies has been the subject of numerous studies. The present research has attempted to discover any positive correlation between MMP-2 and MMP-9 SNPs and prostate cancer (PCa) in patients with a history of either diabetes or smoking habits. 112 PCa-patients and 150 unrelated healthy-controls that matched for age and sex were selected for present case-control study. MMP-2 -1575G/A and MMP-9 -1562 C/T polymorphisms detected by PCR-RFLP, serum tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2), testosterone, prostate-specific antigen (PSA), free-prostate-specific-antigen (fPSA), and fPSA/PSA levels were detected by ELISA and enzyme assay, respectively. MMP-2 and MMP-9 activities were measured by gelatin-zymography. Covariates were considered as age, status of cigarette smoking, and a possible history of diabetes mellitus (DM). The frequency of -1575 MMP-2 A/A + A/G and -1562 MMP-9 C/T + T/T genotypes were higher in PCa-patients with DM (74.3%,p = 0.003) and with smoking habits (72.5%,p = 0.005). These genotypes were associated with the increased risk of prostate cancer in smokers (3.52-folds) and in individuals with history of DM (4.34-folds). A significant positive association was found between level of TIMPs (TIMP -1 and TIMP-2) and BMI in PCa-patients and also between testosterone levels and MMP-9 activity in healthy control subjects. For the first time, this study demonstrated that activities of MMP-2 -1575G/A and MMP-9 -1562C/T variants in association with smoking and diabetes are considered significant risk factors for PCa.

Assimilation of exogenous cyanide cross talk in Oryza sativa L. to the key nodes in nitrogen metabolism.

Exogenous cyanide (CN-) effects on nitrogen (N) uptake, transport, and assimilation in rice seedlings were investigated at the biochemical and molecular levels. Seedlings were treated with either a 2-d or 4-d supply of potassium cyanide (KCN) in the nutrient solution containing nitrate (NO3-) or ammonium (NH4+). Although a KCN-induced increase was recorded in the activity of ß-cyanoalanine synthase (ß-CAS) in rice tissues of both NH4+-fed and NO3--fed seedlings, the former showed a significantly greater assimilation rate for CN- than the latter. The addition of KCN decreased NO3- uptake and assimilation, whereas a negligible impact was observed in NH4+ treatments. Enzymatic assays showed a marked activities enhancement of glutamine synthetase (GS), glutamate synthase (GOGAT), and glutamate dehydrogenase (GDH) in NH4+-fed seedlings after KCN exposure. Similarly, the rises occurring in nitrate reductase (NR) and GDH activity in NO3--fed seedlings were also detected after 2-d exposure to KCN, whereas a significant reduction of GS and GOGAT activities was determined. The results suggest that although exogenous KCN at moderate or high concentrations caused repressively effects on biomass growth of both NH4+-fed and NO3--fed rice seedlings, the nontoxic concentration of KCN supplied can serve as a supplemental N source in plant nutrition and N metabolism.

Application of non-cooperative dynamic game theory for groundwater conflict resolution.

The opposing objectives of the groundwater stakeholders, ranging from maximum withdrawal for economic gain to minimum withdrawal for aquifer and environmental protection, lead stakeholders to behave non-cooperatively. In this study, dynamic non-cooperative games are applied to model these conflicts. These games incorporate stakeholders' non-cooperative decision-making processes and groundwater exploitation details over time. The two key players considered in this study are the government, which aims to minimize the groundwater drawdown, and local farmers, who pursue maximum economic gain. In order to calculate the players' payoffs over the modeling period, a simulation-optimization model is developed. For evaluation, the proposed methodology is implemented in the Bad-Khaledabad study area in Iran. Therefore, two dynamic non-cooperative games are developed, considering weak governmental power and players' interaction. It is concluded that creating a transactional relationship, involving the cropping patterns changes and the irrigation efficiency enhancement, will increase farmers' profits by 28% and decrease withdrawal from the aquifer by 21%.

The role of early office-based needle aspiration in the management of subperiosteal hematoma.

Subperiosteal hematoma of the orbit is a rare complication that may occur in different situations. The most common cause is blunt trauma to the head region. The victims are usually young boys and the common site is usually orbital roof. There is no uniform approach in the literature in the management of subperiosteal hematoma. Conservative management has been recommended in cases with intact visual function. If conservative management is planned, complete resorption of hematoma may last several months, and the patients must tolerate diplopia and varying degrees of proptosis in this relatively long period of time. In this study, four boys (12-15 years) were referred to our clinic with a provisional diagnosis of subperiosteal hematoma after blunt trauma no more than 10 days after initial trauma. Although in our patients, no one had compressive optic neuropathy, they underwent hematoma aspiration and nearly 7 ml dark blood was drained. All procedures were performed in an office-based setting without local anesthesia or sedation and the patients tolerated the procedure comfortably and the procedure was uneventful. When there is no indication for orbitotomy in cases of subperiosteal hematoma, early office-based needle aspiration in comparison to follow-up or administration of steroid, is a viable approach because of its feasibility, an office-based treatment that obviates the need for general anesthesia and yields immediate recovery.

Using fuzzy logic approach to predict work-related musculoskeletal disorders among automotive assembly workers.

Background: Musculoskeletal disorders (MSDs) are considered an important health concern, particularly in automotive assembly industries. Evaluation of the effects of all MSDs risk factors is difficult due to its multifactorial nature. In addition, the risk factors cannot be detected accurately when they are only based on individual opinions. Thus, in this study, fuzzy logic tool was used to evaluate the combined effects of all risk factors on MSDs. Methods: This cross sectional study was conducted on 100 male workers in an automotive industry. Job satisfaction, job stress, job fatigue, and body posture were evaluated by a self-reported questionnaire. Body posture was evaluated using Rapid Entire Body Assessment (REBA). Primary data analysis on extracting the input variables of MATLAB was performed by SPSS 22, with a significant level of 0.05. T test, one-way Anova, and Pearson correlation analysis were used to extract the input variables for the fuzzy logic model. The results obtained from the Nordic questionnaire was selected as the output of the fuzzy model. Fuzzy logic assessment was performed using MATLAB software version 7.0. Results: There were significant differences between WMSDs factors, including job fatigue, strain, working posture, and the REBA final score, and pain in all limbs of the body (p<0.05). A significant difference was also found between working posture with wrist score (p<0.05). The findings on defuzzification showed a strong correlation between real and modelling results. Conclusion: The results showed that many factors such as posture, fatigue, and strain affect MSDs. Based on the obtained results, all categories of risk factors, including personal, psychosocial, and occupational, should be considered to predict MSDs, which can be achieved by a modeling approach.

Two-phase vesicles: a study on evolutionary and stationary models.

In the current article, the dynamic evolution of two-phase vesicles is presented as an extension to a previous stationary model and based on an equilibrium of local forces. In the simplified model, ignoring the effects of membrane inertia, a dynamic equilibrium between the membrane bending potential and local fluid friction is considered in each phase. The equilibrium equations at the domain borders are completed by extended introduction of membrane section reactions. We show that in some cases, the results of stationary and evolutionary models are in agreement with each other and also with experimental observations, while in others the two models differ markedly. The value of our approach is that we can account for unresponsive points of uncertainty using our equations with the local velocity of the lipid membranes and calculating the intermediate states (shapes) in the consequent evolutionary, or response, path.

Tropical stormwater nutrient degradation using nano-TiO2 in photocatalytic reactor detention pond.

The photo-degradation of nutrients in stormwater in photocatalytic reactor wet detention pond using nano titanium dioxide (TiO2) in concrete was investigated in a scale model as a new stormwater treatment method. Degradation of phosphate and nitrate in the presence of nano-TiO2 under natural ultra violet (UV) from tropical sunlight was monitored for 3 weeks compared with normal ponds. Two types of cement, including ordinary Portland and white cement mixed with TiO2 nano powder, were used as a thin cover to surround the body of the pond. Experiments with and without the catalyst were carried out for comparison and control. Average Anatase diameter of 25 nm and Rutile 100 nm nano particles were applied at three different mixtures of 3, 10 and 30% weight. The amounts of algae available orthophosphate and nitrate, which cause eutrophication in the ponds, were measured during the tests. Results revealed that the utilization of 3% up to 30% weight nano-TiO2 can improve stormwater outflow quality by up to 25% after 48 h and 57% after 3 weeks compared with the control sample in normal conditions with average nutrient (phosphate and nitrate) removal of 4% after 48 h and 10% after 3 weeks.

Prediction of the compression ratio for municipal solid waste using decision tree.

The compression ratio of municipal solid waste (MSW) is an essential parameter for evaluation of waste settlement and landfill design. However, no appropriate model has been proposed to estimate the waste compression ratio so far. In this study, a decision tree method was utilized to predict the waste compression ratio (C'c). The tree was constructed using Quinlan's M5 algorithm. A reliable database retrieved from the literature was used to develop a practical model that relates C'c to waste composition and properties, including dry density, dry weight water content, and percentage of biodegradable organic waste using the decision tree method. The performance of the developed model was examined in terms of different statistical criteria, including correlation coefficient, root mean squared error, mean absolute error and mean bias error, recommended by researchers. The obtained results demonstrate that the suggested model is able to evaluate the compression ratio of MSW effectively.

Post cataract surgery refractive surprise due to intraocular lens mislabeling.

Key Clinical Message: If an intraocular lens (IOL) is incorrectly labeled, problems can arise for surgeons and patients. Precise biometry is important to accurately determine the IOL power and prevent the implantation of the wrong IOL. Labeling and verifying IOLs with accuracy is crucial to ensuring the best possible results of cataract surgery. Abstract: Mislabeling of IOLs can cause unpredictable problems for surgeons. However, we can prevent incorrect IOLs by using precise biometry to determine accurate IOL power and safely implant the correct IOL. A 50-year-old female with no medical or ocular history came to our clinic complaining of decreased vision in both eyes that had been ongoing for several months. After being diagnosed with cataracts, primary angle closure suspect, and high hyperopia, the patient underwent phacoemulsification surgery. A posterior chamber IOL was implanted, and visco-goniosynechialysis was performed. During follow-up appointments, it was discovered that the patient had an uncorrected visual acuity of 20/50 in her right eye, which was corrected to 20/20 with a + 7.00 D lens. Upon further evaluation, it was determined that the source of the error was due to a manufacturing mislabeling of the IOL power. The patient then underwent successful IOL exchange surgery, and her best-corrected visual acuity became 20/20 with no significant refraction. This case highlights an uncommon source of refractive surprise after phacoemulsification surgery, successfully managed with IOL exchange surgery using the same IOL power from a different brand.

A review of the degradation of antibiotic contaminants using advanced oxidation processes: modification and application of layered double hydroxides based materials.

In recent years, the treatment of organic pollutants has become a global concern due to the threat to human health posed by emerging contaminants, especially antibiotic contamination. Advanced oxidation processes (AOPs) can solve the organic pollution problem well, which have been identified as a promising solution for the treatment of hard-to-handle organic compounds including antibiotic contaminants. Layered double hydroxides (LDHs) are excellent catalysts because of their flexible tunability, favorable thermal stability, abundant active sites, and facile exchangeability of intercalated anions. This paper conducted a systematic review of LDHs-based materials used for common antibiotic removal by three significant AOP technologies, such as photocatalysis, the Fenton-like processes, and peroxymonosulfate catalysis. The degradation effects studied in various studies were reviewed, and the mechanisms were discussed in detail based on the type of AOPs. Finally, the challenges and the application trends of AOPs that may arise were prospected. The aim of this study is to suggest ways to provide practical guidance for the screening and improvement of LDH materials and the rational selection of AOPs to achieve efficient antibiotic degradation. This could lead to the development of more efficient and environmentally friendly materials and processes for degrading antibiotics, with significant implications for our ecological conservation by addressing water pollution.

Effective adsorption of Pb(ii) from wastewater using MnO2 loaded MgFe-LD(H)O composites: adsorption behavior and mechanism.

Pb(ii) adsorption by MnO2/MgFe-layered double hydroxide (MnO2/MgFe-LDH) and MnO2/MgFe-layered metal oxide (MnO2/MgFe-LDO) materials was experimentally studied in lab-scale batches for remediation property and mechanism analysis. Based on our results, the optimum adsorption capacity for Pb(ii) was achieved at the calcination temperature of 400 °C for MnO2/MgFe-LDH. Langmuir and Freundlich adsorption isotherm models, pseudo-first-order and pseudo-second-order kinetics, Elovich model, and thermodynamic studies were used for exploring the Pb(ii) adsorption mechanism of the two composites. In contrast to MnO2/MgFe-LDH, MnO2/MgFe-LDO400 °C has a stronger adsorption capacity and the Freundlich adsorption isotherm model (R2 > 0.948), the pseudo-second-order kinetic model (R2 > 0.998), and the Elovich model (R2 > 0.950) provide great fits to the experimental data, indicating that the adsorption occurs predominantly via chemisorption. The thermodynamic model suggests that MnO2/MgFe-LDO400 °C is spontaneously heat-absorbing during the adsorption process. The maximum adsorption capacity of MnO2/MgFe-LDO400 °C for Pb(ii) was 531.86 mg g-1 at a dosage of 1.0 g L-1, pH of 5.0, and temperature of 25 °C. Through characterization analysis, the main mechanisms involved in the adsorption process were precipitation action, complexation with functional groups, electrostatic attraction, cation exchange and isomorphic replacement, and memory effect. Besides, MnO2/MgFe-LDO400 °C has excellent regeneration ability in five adsorption/desorption experiments. The above results highlight the powerful adsorption capacity of MnO2/MgFe-LDO400 °C and may inspire the development of new types of nanostructured adsorbents for wastewater remediation.

Diversity, Distribution, and Biogeography of Freshwater Fishes in Guangxi, China.

The Guangxi Zhuang Autonomous Region has the largest number of cavefish species in the world and is a global biodiversity hotspot. In this study, a species list of freshwater fishes in 12 Sub-basins of Guangxi was compiled systematically. Moreover, the species composition and distribution of the diversity were analyzed via the G-F index, taxonomic diversity index, and beta diversity index. Results showed that 380 species of freshwater fishes were recorded in this region, which belonged to 158 genera in 43 families and 17 orders in 2 phyla, in which 128 species of endemic fishes and 83 species of cavefish accounted for 33.68% and 21.84%, respectively. The species diversity from northwest to southeast gradually decreased for most Sub-basins. The G-F index has generally risen in recent years. The taxonomic diversity index showed that the freshwater fish taxonomic composition in Guangxi is uneven. The spatial turnover component was the main contributor to beta diversity. A cluster analysis showed that the 12 Sub-basins in the study area could be divided into four groups, and the phylogenetic relationships of freshwater fishes in Guangxi generally reflect the connections between water systems and geological history. The freshwater fish system in Guangxi, which belonged to the South China division in the Southeast Asiatic subregion of the Oriental region, originated in the early Tertiary period. The results will provide the information needed for freshwater fish resource protection in Guangxi and a reference for promoting the normalization of fish diversity conservation in the Pearl River Basin and other basins.

Enhancing mechanism of arsenic(iii) adsorption by MnO2-loaded calcined MgFe layered double hydroxide.

The use of MnO2/MgFe-layered double hydroxide (MnO2/MgFe-LDH) and MnO2/MgFe-layered double oxide (MnO2/MgFe-LDO400 °C) for arsenic immobilization from the aqueous medium is the subject of this research. Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy were used to characterise MnO2/MgFe-LDH and MnO2/MgFe-LDO400 °C. Based on our developed method, MnO2 was spread on the clay composites' surfaces in the form of a chemical bond. The clay composite exhibited a good adsorption effect on arsenic. The experimental findings fit the pseudo-second-order model well, indicating that the chemisorption mechanism played a significant role in the adsorption process. Furthermore, the Freundlich model suited the adsorption isotherm data of all adsorbents well. The recycling experiment showed that MnO2/MgFe-LDH and MnO2/MgFe-LDO400 °C exhibited good stability and reusability. In summary, MnO2/MgFe-LDH and MnO2/MgFe-LDO400 °C are promising for developing processes for efficient control of the pollutant arsenic.

Halogenated organic pollutants (HOPs) in marine fish from the Beibu Gulf, South China Sea: Levels, distribution, and health risk assessment.

Six marine fish species, collected from the Beibu Gulf were statistically analyzed for polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and dichlorodiphenyltrichloroethanes (DDTs). The concentrations of ∑14PBDEs, ∑26PCBs, and ∑6DDTs ranged from 11.8-1431, 8.74-495, and 9.47-1263 ng g-1 lipid weight (lw), respectively. In general, PBDEs were the predominant halogenated organic pollutants (HOPs) in the Beibu Gulf. The homologues profiles of Mugil cephalus and Trichiurus nanhaiensis differed from other four species. For example, the contributions of deca-BDEs in M. cephalus (14 %) and T. nanhaiensis (1 %) were lower than other four species (56 %). The ratio of (DDE + DDD)/ΣDDTs in all samples was >0.5, indicating that DDTs were mainly derived from historical residues. Intakes of HOPs through the consumption of the marine fish from the study areas might not subject residents of the coastal areas in the Beibu Gulf to health risks.

Challenges of Emergency Medical Services Response to Arasbaran Twin Earthquakes; a Content Analysis.

Introduction: One of the most important concerns in responding to disasters is providing Basic Life Support (BLS) services. Considering the key role of Emergency Medical Services (EMS) in providing BLS, the purpose of this study is to investigate the experience of provincial EMS during their response to the Arasbaran twin earthquakes and its challenges in Iran. Methods: This study was conducted using a qualitative approach and the conventional content analysis method. Data were collected through Focused Group Discussions (FGD) and semi-structured in-depth interviews with purposively-selected EMS paramedics and officials in East Azerbaijan Province, Iran. To form the main categories, the interviews were encoded in three stages and the similar codes were placed under the same subcategories and merged. Results: A total of 26 EMS paramedics participated in the study. The codes extracted from the interviews, after three stages of reduction, were placed in the top ten categories, including the lack of preparedness and coordination, dead bodies' management challenges, responders' psychosocial support, deficiencies in supplies and ambulances, difficulty of access to rural areas, volunteer management, non-documentation of the experiences, communication challenges, recalling, and deploying of EMS responders. Conclusion: Timely response of the EMS and paramedics' sense of responsibility for providing services were positive and successful points about the emergency response operations. The weaknesses of EMS should, therefore, be addressed through transferring of experiences and by planning and arranging training courses.