Designing a conceptual model for dynamic empowerment of medical science education managers.

BACKGROUND: Educational managers at universities of medical sciences are the suppliers of human resources to the healthcare system. Thus, attention to their professional empowerment can play a prominent role in improving the quality of medical science education. MATERIALS AND METHODS: The present study was implemented through the method of modeling and in the three stages of conceptual, modeling, and validation. The research environment was the medical science universities of Iran and the sampling method was purposive. The two qualitative approaches of literature review and semi-structured interview were used to develop the components of the model. The results were then integrated, the relationships between the components were investigated, and the model was eventually finalized. The resulting scores were analyzed using MicMac software. RESULTS: Twelve categories and 20 subcategories were identified in the first micro-study (desk research). Qualitative analysis of the interviews in the second stage led to the identification of 21 subcategories and seven categories. Components of the conceptual model were extracted from the results of the two first stages, both of which were aimed at the extraction of concepts relevant to dynamic empowerment of medical science educational managers, and the conceptual model for dynamic empowerment of medical science education managers was designed in the six categories of education, decision-making, organization, belief, dynamic capabilities, and environment after the interactions between the components were studied. CONCLUSIONS: Results of the present study revealed that dynamic empowerment of the managers is a multifaceted and multidimensional concept, and all of the factors incorporated in the conceptual model for dynamic empowerment of managers must receive special attention.

Health risk assessment of the European inhabitants exposed to contaminated ambient particulate matter by potentially toxic elements.

PM10-associated potential toxic elements (PTEs) can enter the respiratory system and cause health problems. In the current study, the health risk indices caused by PM10 inhalation by adults, children, and infants in 158 European cities between 2013 and 2019 were studied to determine if Europeans were adversely affected by carcinogenic and non-carcinogenic factors or not. The Mann-Kendall trend test examined PM10's increasing or decreasing trend. Random Forest analysis was also used to analyse meteorological factors affecting PM10 in Europe. Hazard quotient and cancer risk were estimated using PM10-associated PTEs. Our results showed a decline in continental PM10 concentrations. The correlation between PM10 concentrations and temperature (-0.40), PBLH (-0.39), and precipitation were statistically strong (-0.21). The estimated Pearson correlation coefficients showed a statistically strong positive correlation between As & Pb, As & Cd, and Cd & Pb during 2013-2019, indicating a similar origin. PTEs with hazard quotients below one, regardless of subpopulation type, posed no noncancerous risk to Europeans. The hazard quotient values positively correlated with time, possibly due to elevated PTE levels. In our study on carcinogen pollution in Europe between 2013 and 2019, we found unacceptable levels of As, Cd, Ni, and Pb among adults, children, and infants. Carcinogenic risk rates were highest for children, followed by infants, adult women, and adult men. Therefore, besides monitoring and mitigating PM concentrations, effective control of PM sources is also needed.

Epidemiological update on prevalence and incidence of overweight and obesity in adults in the south-east of the Islamic Republic of Iran: findings from the Kerman Coronary Artery Diseases Risk Factors Study (KERCADRS).

BACKGROUND: Obesity is common worldwide, especially in low- and middle-income countries. AIMS: To update data on the prevalence of overweight, obesity and central obesity, and to measure incidence rates for such outcomes in adults living in the south-east of the Islamic Republic of Iran. METHODS: We enrolled 9997 adults (aged 15-80 years) between 2014 and 2018 (phase 2); 2820 of whom had participated in phase 1 (2009-2011). Participants were examined for overweight, obesity, central obesity, diabetes, hypertension, low physical activity, and dyslipidaemia. Univariate and multivariate logistic regression models were used to determine the potential predictors of overweight, obesity and central obesity, and adjusted odds ratios (AOR) were obtained. Incidence rate of overweight, obesity and central obesity was reported among those who had none of these outcomes in phase 1. RESULTS: The prevalence was 35.8% (37% men, 35% women) for overweight, 22.3% (16% men, 26.3% women) for obesity, and 31.1% (15.6% men, 41.2% women) for central obesity. The prevalence of overweight/obesity was significantly associated with age (AOR = 2.8-7.4), higher education (AOR = 1.7), female gender (AOR = 1.4), low physical activity (AOR = 1.3), smoking (AOR = 0.55) and opium use (AOR = 0.79). The prevalence increased from 33.3% to 35.8% for overweight and from 15.4% to 22.3% for obesity between phases 1 and 2. The incidence rate per 100 person-years was 5.5 for overweight, 4.7 for obesity and 2.9 for central obesity. CONCLUSION: Prevalence of overweight and obesity increased over 5 years. Middle-aged participants, women, and those with low physical activity were at higher risk for overweight/obesity.

Interplay between MAPK/ERK signaling pathway and MicroRNAs: A crucial mechanism regulating cancer cell metabolism and tumor progression.

Mitogen-activated protein kinase (MAPK) signal transduction, as a highly conserved signaling pathway, is reported to be involved in various biological events, including metabolic reprogramming, cell proliferation, survival, and differentiation. Mutations in key molecules involved in MAPK/ERK signaling and dysregulation of this pathway are very common events in various human malignancies, which make the MAPK signaling a crucial signaling pathway participating in the regulation of glucose uptake by malignant cells and tumorigenesis. MicroRNAs (miRNAs), as small non-coding RNAs, are critical regulators of gene expression that play key roles in cancer initiation and progression. On the other hand, these small RNAs mutually regulate the MAPK signaling which is often overexpressed in the case of cancer progression; suggesting that crosstalk between miRNAs and this signaling pathway plays a pivotal role in the development of human cancers. Some miRNAs such as miR-20b, miR-34c-3p, miR-152, miR-181a, and miR-302b through inhibiting MAPK signaling, and miR-193a-3p, miR-330-3p, and miR-592 by activating this signaling pathway, play imperative roles in tumorigenesis. Therefore, in this review, we aimed to focus on the interplay between miRNAs and MAPK signaling in the various steps of tumorigenesis, including metabolic regulation, cell proliferation, apoptosis, metastasis, angiogenesis, and drug resistance.

Safety and efficacy of Favipiravir in moderate to severe SARS-CoV-2 pneumonia.

BACKGROUND: We examined the safety and efficacy of a treatment protocol containing Favipiravir for the treatment of SARS-CoV-2. METHODS: We did a multicenter randomized open-labeled clinical trial on moderate to severe cases infections of SARS-CoV-2. Patients with typical ground glass appearance on chest computerized tomography scan (CT scan) and oxygen saturation (SpO2) of less than 93% were enrolled. They were randomly allocated into Favipiravir (1.6 gr loading, 1.8 gr daily) and Lopinavir/Ritonavir (800/200 mg daily) treatment regimens in addition to standard care. In-hospital mortality, ICU admission, intubation, time to clinical recovery, changes in daily SpO2 after 5 min discontinuation of supplemental oxygen, and length of hospital stay were quantified and compared in the two groups. RESULTS: 380 patients were randomly allocated into Favipiravir (193) and Lopinavir/Ritonavir (187) groups in 13 centers. The number of deaths, intubations, and ICU admissions were not significantly different (26, 27, 31 and 21, 17, 25 respectively). Mean hospital stay was also not different (7.9 days [SD = 6] in the Favipiravir and 8.1 [SD = 6.5] days in Lopinavir/Ritonavir groups) (p = 0.61). Time to clinical recovery in the Favipiravir group was similar to Lopinavir/Ritonavir group (HR = 0.94, 95% CI 0.75 - 1.17) and likewise the changes in the daily SpO2 after discontinuation of supplemental oxygen (p = 0.46) CONCLUSION: Adding Favipiravir to the treatment protocol did not reduce the number of ICU admissions or intubations or In-hospital mortality compared to Lopinavir/Ritonavir regimen. It also did not shorten time to clinical recovery and length of hospital stay.

Should all patients with hypertension be worried about developing severe coronavirus disease 2019 (COVID-19)?

BACKGROUND: Hypertension, the most common comorbidity among coronavirus disease 2019 (COVID-19) patients, is accompanied by worse clinical outcomes, but there is lack of evidence about prognostic factors among COVID-19 patients with hypertension. We have come up with some prognostic factors to predict the severity of COVID-19 among hypertensive patients. In addition, epidemiologic, clinical and laboratory differences among COVID-19 patients with and without underlying hypertension were evaluated. METHODS: Medical profiles of 598 COVID-19 cases were analyzed. Patients were divided into two comparative groups according to their positive or negative history of hypertension. Then, epidemiologic, clinical, laboratory and radiological features and also clinical outcomes were compared. RESULTS: 176 (29.4%) patients had underlying hypertension. Diabetes was significantly higher in hypertensive group [72 (40.9%) vs 76 (18%)] (P-value: 0.001). Cardiovascular and renal disorders were significantly higher in hypertensive patients. (P-value: 0.001 and 0.013 respectively). In COVID-19 patients with hypertension, severe/critical types were significantly higher. [42(23.8%) vs. 41(9.7%)], (P-value: 0.012). In the logistic regression model, Body mass index > 25 (ORAdj: 1.8, 95% CI: 1.2 to 2.42; P-value: 0.027), age over 60 (ORAdj: 1.26, 95% CI: 1.08 to 1.42; P-value: 0.021), increased hospitalization period (ORAdj: 2.1, 95% CI: 1.24 to 2.97; P-value: 0.013), type 2 diabetes (ORAdj: 2.22, 95% CI: 1.15 to 3.31; P-value: 0.001) and chronic kidney disease (ORAdj: 1.83, 95% CI: 1.19 to 2.21; P-value: 0.013) were related with progression of COVID-19. CONCLUSION: Hypertensive patients with Age > 60-year-old, BMI > 25 Kg/m2, CVD, diabetes and chronic kidney disease are associated with poor outcomes in those with COVID-19 infection.

The effect of different pulp-capping materials on proliferation, migration and cytokine secretion of human dental pulp stem cells.

OBJECTIVES: Biocompatibility of dental biomaterials plays a critical role in regeneration of dental stem cells. The aim of present study was to evaluate the effects of novel biomaterials of TheraCal-LC (TheraCal; Bisco), Angelus mineral trioxide aggregate (MTA; Angelus), calcium-enriched mixture (CEM; BioniqueDent), and Biodentine (Septodont) on viability of human dental pulp stem cells (hDPSCs). Moreover, the recruitment of dental pulp stem cells is a prerequisite for regeneration of damaged dentin. Therefore, in this study the effects of mentioned biomaterials on migration of hDPSCs and the secretion of some chemoattractive molecules by these cells were examined. MATERIALS AND METHODS: The cell viability of hDPSCs was assessed using MTT assay. Transwell migration assay was used to determine cell migration ability. The cytokine secretion was evaluated using enzyme-linked immunosorbent assay. RESULTS: The biomaterials of MTA, CEM, and Biodentine at different dilutions had no cytotoxic effects on hDPSCs at different time points; however, non-diluted extract of TheraCal showed toxic effects after 24, 48, and 72 hr. Meanwhile, the highest cell migration was observed in the presence of CEM and Biodentine (P<0.05). The secretion of MCP-1 and TGF-ß1 were higher in hDPSCs treated with Biodentine compared to some other groups (P<0.05, P<0.01). Moreover, TheraCal decreased protein secretion of TNF-α (P<0.05), and IL-8 (P<0.01) in hDPSCs. CONCLUSION: The biological compatibility associated with CEM and Biodentine indicates promising applications in the field of vital pulp therapy.

Motivating medical students for social accountability in medical schools.

INTRODUCTION: As health professionals, physicians are accountable for their professional practice.  The aim of this study was to explain the medical students' motivation to attain social accountability in medical schools, based on the experience of both students and faculties. METHODS: We conducted a qualitative conventional content analysis research in Shiraz University of medical sciences in Iran since 2018 through purposive, snowball sampling. The data were collected through semi-structured interviews with 35 participants i.e., medical students and teachers. Coding was carried out by conventional content analysis. RESULTS: We drew four themes and ten related subthemes and the central variable explains the motivation of medical students toward social accountability and makes a link among the subthemes, was purposeful beliefs and behavior. The key dimensions during motivational process which generated the social accountability development in medical students consisted of social culture of medicine, medical school reality, teaching and learning strategy and creating purposeful beliefs and behavior. Also, eight subthemes of individual motivation, content motivation process motivation, attending to the outcomes of the curriculum, traditional routine centered curriculum, observational learning, role modeling, hidden curriculum, respect for social values and norms and benefitting the society emerged which explain the process of motivate for social accountability by creating purposeful beliefs and behavior in medical students. CONCLUSIONS: The core variable of motivation toward social accountability must be reflected in future developmental programs, curriculum planning and training general physicians. In other words, the best efforts for purposeful beliefs and behavior in medical students, must be made to improve motivation toward social accountability.

Sulforaphane Modulates Cell Migration and Expression of ß-Catenin and Epithelial Mesenchymal Transition Markers in Breast Cancer Cells.

BACKGROUND: We aimed to assess the effect of sulforaphane (SFN) on breast cancer cell migration and also its effect on the expression of epithelial mesenchymal transition (EMT) markers and ß-catenin. METHODS: This study was performed in Shahroud University of Medical Sciences, Shahroud, Iran from 2017-2018. In this experimental study, MDA-MB-231 cells were treated with different concentrations of SFN (5, 10, 20, 30 and 40 µM) at different time points of 24, 48, and 72 h. The control group was untreated cells. The inhibitory effects of different concentrations of SFN on cell migration at different time points were evaluated using scratch assay. Moreover, apoptosis was assessed by using flow cytometric analysis. The expression of ß-catenin and EMT markers of ZEB1, fibronectin, and claudin-1 were determined by real-time PCR. Western blotting analysis of ß-catenin was applied to determine its changes after SFN treatment. RESULTS: SFN markedly inhibited the migration of cells at concentrations of 10, 20, 30, and 40µM after 24, 48, and 72 h. At relatively, high concentrations (30, 40µM), SFN induced apoptosis. Moreover, SFN reduced the gene expression of ZEB1, fibronectin, and claudin-1 after 72 h. The expression of ß-catenin revealed a time-dependent decrease at the concentration of 40 µM SFN. CONCLUSION: Downregulation of EMT markers and ß-catenin showed accordance with the inhibition of migration. SFN could be a promising drug candidate to reduce metastasis in breast cancer.

Towards a circular economy: A comprehensive study of higher heat values and emission potential of various municipal solid wastes.

Maximizing resource recovery from waste streams (e.g., energy) is a critical challenge for municipalities. Utilizing the ultimate analysis and high heat value (HHV), we investigated the energy recovery and emission characteristics for 252 solid wastes of a diverse range of geographical origins classifications (e.g., 30 paper, 12 textile, 12 rubber and leather, 29 MSW mixture, 34 plastic, 61 wood, 20 sewage sludge and 53 other wastes) under the thermal waste-to-energy operation. Given the significance of wastes' HHV data, we proposed a rapid and cost-effective methodology for filling the gaps in the experimental data by prediction of the missing or uncertain wastes' HHV. We further employed wastes' nitrogen and sulphur contents to assess their atmospheric emissions. The results from this analysis show the highest energy content belonged to plastic waste, but higher levels of air pollution (mainly due to nitrogen and sulfur) could be emitted during thermal energy recovery of sewage sludge, rubber, and textile wastes. Also, we demonstrated more significant potential for recovering energy from plastic, wood, and paper wastes, while emitting less nitrogen and sulphur compounds to the atmosphere. Finally, our presented HHV models outperform concerning generalizability, validity, and accuracy when comparing the obtained results to those of previously published models. The results from this present study are particularly advantageous in designing sustainable thermal waste-to-energy systems to facilitate cities' transition into a circular economy.

Nutrient Deprivation Modulates the Metastatic Potential of Breast Cancer Cells.

BACKGROUND: Breast cancer is the leading cause of cancer related death in women worldwide. The development of metastatic cancer is the main factor contributing to mortality. The molecular mechanisms underlying the metastatic process have yet to be clearly elucidated. However, the interplay between the tumor microenvironment and the cancer cells hold a critical role in influencing the progression of cancer metastasis. Within the microenvironment of solid tumors, the lack of sufficient vasculature leads to the development of nutrient deprived conditions. This study aimed to examine how nutrient deprivation influences factors involved in cancer progression and metastasis. Specifically, we examined how nutrient stress changes cancer cell migration, the gene expression, and cytokine production of metastasis-related factors in a human breast cancer cell line. METHODS: MCF7 breast cancer cells were cultured in serum-free media for 24, 48, and 72 h. Cell migration was evaluated using a transwell migration assay. The transcriptional expression of metastatic related genes was examined via real-time PCR. Cytokine production was examined via enzyme-linked immunosorbent assay. RESULTS: Nutrient deprivation of the MCF7 cells significantly reduced cell migration after 24 h. However, following 72 h of nutrient deprivation, there was significant increase in cell migration compared to the 24 h group. Transcriptional expression of markers involved in migration including, ß-catenin, twist, vimentin, fibronectin, ICAM1, VCAM1, and VEGF were up regulated after 72 h of nutrient deprivation. The cytokines TGFß1, IL-8, and MCP1 were differentially secreted. CONCLUSION: Nutrient deprivation is an environmental stress factor that can influence the behavior of cancer cells. Current treatments implement nutrient deprivation as a potential cancer treatment. Under short periods of nutrient deprivation, cancer cell migration is inhibited. However, our findings show that following extended lengths of nutrient deprivation, cancer cells are capable of adapting themselves to the environmental condition and restoring their migratory abilities. This, in part, may be a result of increased expression of metastasis-related genes. Further research is required to accurately identify how the expression of metastasis-related genes is modulated and controlled in response to nutrient deprivation and environmental stress.

High-Resolution FBG-Based Fiber-Optic Sensor with Temperature Compensation for PD Monitoring.

This paper presented a new sensor to detect and localize partial discharge (PD) in power transformers based on a fiber Bragg grating (FBG). The fundamental characteristics of the proposed sensor, as a PD detector, were temperature compensation and direction independence. The proposed high-resolution PD detector operated based on the FBG wavelength shift. It is necessary to evaluate the physical parameters of the sensor to achieve the best results. Therefore, in this paper, the detected signal strength was investigated for different angles and temperatures. A Teflon hollow mandrel and two FBGs attached to the inner and outer surfaces of the hollow mandrel were chosen as the inner transformer PD detector. The changes in the sensor output were less than 0.4 mV and 0.5 mV for direction variations and a temperature variation of 14 °C (degrees Celsius), respectively. Consequently, the proposed sensor could be successfully employed for the detection of a transformer PD signal.

Gene Expression Changes in Pomegranate Peel Extract-Treated Triple-Negative Breast Cancer Cells.

BACKGROUND: Triple-negative breast cancer (TNBC) is treated with highly aggressive non-targeted chemotherapies. Safer and more effective therapeutic approaches than those currently in use are needed. Natural pomegranate peel extract (PPE) has recently been found to inhibit breast cancer progression; however, its mechanisms of action remain unclear. We hypothesized that transcriptional changes in the genes encoding the adherence proteins of intercellular adhesion molecule-1 (ICAM-1) and vascular endothelial growth factor (VEGF), may explain, at least in part, the anti-metastatic properties of PPE. Recently, the tumor microenvironment has been recognized as a key contributor to cancer progression. We speculated that PPE acts by modulating matrix glycoproteins including MMP9 and fibronectin. Moreover, we hypothesized that VEGF, which is required for tumor development, may contribute to the antimetastatic effects of PPE. METHODS: To address these possibilities, MDA-MB-231 cells were treated with different doses of PPE at different time points. Apoptosis was detected by flow cytometry using annexin V and propidium iodide. Cell migration was detected with a transwell assay. Gene expression changes were analyzed by real-time PCR. RESULTS: Exposure to PPE resulted in TNBC cell death and markedly inhibited PPE-resistant cell migration. Moreover, PPE up-regulated the expression of ICAM-1, a protein essential for cell adhesion, and down-regulated the expression of MMP9, fibronectin, and VEGF, the products of which contribute to cancer cell migration. CONCLUSION: Transcriptional changes in ICAM-1, MMP9, fibronectin, and VEGF may contribute to PPE-mediated antimetastatic effects in TNBC.

Pomegranate peel extract inhibits expression of ß-catenin, epithelial mesenchymal transition, and metastasis in triple negative breast cancer cells.

The standard treatment for triple-negative breast cancer (TNBC) is chemotherapy, which is highly toxic to patients; thereby, there is a need to identify safer and more effective therapeutic approaches. Medicinal plants constitute a common alternative for cancer treatment. Pomegranate is a well-known fruit in this context, but its antimetastatic property has not been extensively studied. As breast cancer-related deaths from TNBC are mainly due to metastasis, the present study was designed to investigate the antimigratory effect of pomegranate peel extract (PPE) on TNBC cells. For this purpose, the MDA-MB-231 cells were treated with different concentrations of PPE for 24, 48 and 72 hr. The effects of PPE on cell migration and invasion were determined by wound healing and transwell assays. To address the possible molecular mechanisms underlying the antimetastatic effect of PPE, real-time quantitative PCR analysis of selected epithelial mesenchymal transition (EMT) markers were performed. Moreover, the expression of ß-catenin as a critical factor in promoting cancer metastasis was examined. PPE markedly inhibited the migration and invasion of cells at concentrations of 25, 50, 100, 250, 500, and 1000µg/ml. At relatively high concentrations (500, 1000µg/ml), PPE induced apoptosis. Moreover, PPE decreased the gene expression of vimentin, ZEB1, and ß-catenin and also increased the expression of E-cadherin in TNBC cells. The protein level of ß-catenin, as measured using western analysis, revealed a time-dependent decrease at the concentration of 1000µg/ml PPE. Downregulation of EMT markers and ß-catenin showed accordance with the inhibition of migration and invasion. The present data show that PPE could be a promising drug candidate to reduce metastasis in TNBC cells.

Effects of Two Calcium Silicate Cements on Transforming Growth Factor-ß1 Secretion from Human Dental Pulp Stem Cells.

Introduction: The aims of this in vitro study were to evaluate the effects of two calcium silicate based cements, Calcum-enriched Mixture (CEM) and Biodentine on proliferation of human dental pulp stem cells (hDPSCs) and the effects of proposed cements on the secretion of Transforming Growth Factor ß1 (TGF-ß1). Methods and materials: The cell cultures of human Dental Pulp Stem Cells (hDPSCs) at passage 3-5 were treated with various dilutions (1/1, 1/2, 1/4, 1/8, 1/16, and 1/32) of CEM and Biodentine extracts to assess the cell proliferation using 3-(4, 5-dimethylthiazol-2-Y1)-2, 5-diphenyltetrazolium brovide (MTT) assay after 48 and 72 h. The amount of TGF-ß 1 secretion were estimated after 72 h using an enzyme-linked immunosorbent assay. Data were analyzed using the one-way analysis of variance (ANOVA) followed by the Dunnett's test at the level of significance set at 0.05. Result: CEM showed the highest rates of cell proliferation compared to Biodentine after 72 h (P<0.05). A greater amount of TGF-ß1 was secreted by hDPSCs treated with Biodentine compared to CEM (P<0.05). These differences were statistically significant (P<0.05). Conclusion: In this in vitro study hDPSCs showed more proliferation capacity with CEM rather than Biodentine and TGF-ß1 secretion rate in Biodentine was higher.

QSPR prediction of the hydroxyl radical rate constant of water contaminants.

In advanced oxidation processes (AOPs), the aqueous hydroxyl radical (HO) acts as a strong oxidant to react with organic contaminants. The hydroxyl radical rate constant (kHO) is important for evaluating and modelling of the AOPs. In this study, quantitative structure-property relationship (QSPR) method is applied to model the hydroxyl radical rate constant for a diverse dataset of 457 water contaminants from 27 various chemical classes. The constricted binary particle swarm optimization and multiple-linear regression (BPSO-MLR) are used to obtain the best model with eight theoretical descriptors. An optimized feed forward neural network (FFNN) is developed to investigate the complex performance of the selected molecular parameters with kHO. Although the FFNN prediction results are more accurate than those obtained using BPSO-MLR, the application of the latter is much more convenient. Various internal and external validation techniques indicate that the obtained models could predict the logarithmic hydroxyl radical rate constants of a large number of water contaminants with less than 4% absolute relative error. Finally, the above-mentioned proposed models are compared to those reported earlier and the structural factors contributing to the AOP degradation efficiency are discussed.

Impact of hydrodynamics on pollutant degradation and energy efficiency of VUV/UV and H2O2/UV oxidation processes.

The Vacuum-UV/UV process, an incipient catalyst/chemical-free advanced oxidation process (AOP), is potentially a cost-effective solution for the removal of harmful micropollutants from water. Utilizing a novel mechanistic numerical model, this work aimed to establish a thorough understanding of the degradation mechanisms in the VUV/UV process operating under continuous flow conditions, when compared with the widely applied H2O2/UV AOP. Of particular interest was the examination of the impact of flow characteristics (hydrodynamics) on the degradation efficacy of a target micropollutant during the VUV/UV and H2O2/UV AOPs. While hydroxyl radical (OH) oxidation was the dominant degradation pathway in both processes, the degradation efficacy of the VUV/UV process showed much stronger correlation with the extent of mixing in the photoreactor. Under a uniform flow regime, the degradation efficiency of the target pollutant achieved by the H2O2/UV process with 2- and 5 ppm H2O2 was greater than that provided by the VUV/UV process. Nonetheless, introduction of mixing and circulation zones to the VUV/UV reactor resulted in superior performance compared with the H2O2/UV AOP. Based on the electrical energy-per-order (EEO) analysis, incorporation of circulation zones resulted in a reduction of up to 50% in the overall energy cost of the VUV/UV AOP, while the corresponding reduction for the 5-ppm H2O2/UV system was less than 5%. Furthermore, the extent of OH scavenging of natural organic matter (NOM) on energy efficiency of the VUV/UV and H2O2/UV AOPs under continuous flow conditions was assessed using the EEO analysis.

A study of enhanced performance of VUV/UV process for the degradation of micropollutants from contaminated water.

VUV/UV is a chemical-free and straightforward solution for the degradation of emerging contaminants from water sources. The objective of this work was to investigate the feasibility of VUV/UV advanced oxidation process for the effective degradation of a target micropollutant, atrazine, under continuous flow operation of 0.5-6.5L/min. To provide an in-depth understanding of process, a comprehensive computational fluid dynamics (CFD) model, incorporating flow hydrodynamics, 185nm VUV and 254nm UV radiation propagation along with a complete kinetic scheme, was developed and validated experimentally. The experimental degradation rates and CFD predicted values showed great consistency with less than 2.9% average absolute relative deviation (AARD). Utilizing the verified model, energy-efficiency of the VUV/UV process under a wide range of reactor configurations was assessed in terms of electrical energy-per-order (EEO), OH concentration as well as delivered UV and VUV dose distributions. Thereby, the extent of mixing and circulation zones was found as key parameter controlling the treatment economy and energy-efficiency of the VUV/UV process. Utilizing a CFD-driven baffle design strategy, an improved VUV/UV process with up to 72% reduction in the total electrical energy requirement of atrazine degradation was introduced and verified experimentally.