Catalytic Degradation of 4-Ethylpyridine in Water by Heterogeneous Photo-Fenton Process

In this work, the degradation of 4-ethylpyridine (4EP) in water by a heterogeneous photo-Fenton process (H2O2/Fe3O4/ultraviolet irradiation (UV)) was investigated. More rapid and effective 4EP degradation was obtained with H2O2/Fe3O4/UV than Fenton-like (H2O2/Fe3O4) and UV/H2O2, which is due to the larger production of hydroxyl radicals from the chemical and photolytic decomposition of H2O2. The operational conditions were varied during 4EP degradation experiments to evaluate the effects of pH, catalyst, concentration, and temperature on the kinetics and efficiency of H2O2/Fe3O4/UV oxidation. Under optimal conditions (100 mg/L 4EP, [H2O2] = 1000 mg/L, Fe3O4 = 40 mg/L, pH = 3 and room temperature, 300 rpm), 4EP was totally declined and more than 93% of the total organic carbon (TOC) was eliminated. Liquid chromatography analysis confirmed the formation of aromatic and aliphatic intermediates (4-hydroxypyridine, 4-pyridone, malonic, oxalic, and formic acids) that resulted in being mineralized. Ion chromatography analysis demonstrated the stoichiometric release of NH4+ ions during 4EP degradation by heterogeneous photo-Fenton oxidation. The reuse of the heterogeneous catalyst was evaluated after chemical and heat treatment at different temperatures. The heat-treated catalyst at 500 °C presented similar activity than the pristine Fe3O4. Accordingly, heterogeneous photo-Fenton oxidation can be an alternative method to treat wastewaters and groundwater contaminated with pyridine derivatives and other organic micropollutants. The combination of heterogeneous photo-Fenton oxidation with classical biological methods can be proposed to reduce the overall cost of the treatment in large-scale water treatment plants. View Full-TextQatar National Librar

Carbetocin versus Oxytocin and Misoprostol in prevention of atonic post-partum hemorrhage in high risk patients planed for cesarean delivery

Background: Post-partum hemorrhage prevention (PPH) is considered a major issue due to its effect on maternal morbidity and mortality. The objective of this study was to compare efficacy of Carbetocin in prevention of atonic post-partum hemorrhage in high risk patients undergoing elective caesarean section in comparison to Oxytocin and Misoprostol.Methods: 150 pregnant women prepared for elective caesarean section were classified into 3 groups; Group I (50 patients received Carbetocin 100 mg I.V infusion), Group II (50 patients received 20 IU of Oxytocin infusion on 1000 ml of normal saline solution) and Group III (50 cases received Misoprostol 400 µg per rectum immediately before induction of anaesthesia). Assessment of PPH and its degree was determined according to amount of blood loss during and for first 24 hours of caesarean delivery, also further need for haemostatic measures were also assessed.Results: There was a statistically significant difference in PPH among the three groups 6, 14 and 12% for group I, II and III respectively (P <0.001), major PPH was 0, 4 and 6% for the same groups respectively (P <0.001). The need for additional uterotonic agents was significantly lesser in Group I compared to Group II and III (2% versus 8 and 12% respectively P = 0.02) also the need for additional surgical measures was significantly lesser among the three groups (P= 0.00). The drop in Hb level and haematocrit value was significantly lesser in group I compared to group II& III (P <0.05). The need for blood transfusion was significantly lesser in Group I compared to group II and III (0% versus 12% p <0.0001)Conclusions: Carbetocin was superior to Oxytocin and Misoprostol in prevention of atonic PPH in high risk patients underwent elective caesarean delivery. Carbetocin should be administered for all cases undergoing elective CS and carry a risk factor for postpartum hemorrhage.

Electrolytic oxidation as a sustainable method to transform urine into nutrients

© 2020 by the authors. In this work, the transformation of urine into nutrients using electrolytic oxidation in a single-compartment electrochemical cell in galvanostatic mode was investigated. The electrolytic oxidation was performed using thin film anode materials: boron-doped diamond (BDD) and dimensionally stable anodes (DSA). The transformation of urine into nutrients was confirmed by the release of nitrate (NO3-) and ammonium (NH4 +) ions during electrolytic treatment of synthetic urine aqueous solutions. The removal of chemical oxygen demand (COD) and total organic carbon (TOC) during electrolytic treatment confirmed the conversion of organic pollutants into biocompatible substances. Higher amounts of NO3-and NH4 + were released by electrolytic oxidation using BDD compared to DSA anodes. The removal of COD and TOC was faster using BDD anodes at different current densities. Active chlorine and chloramines were formed during electrolytic treatment, which is advantageous to deactivate any pathogenic microorganisms. Larger quantities of active chlorine and chloramines were measured with DSA anodes. The control of chlorine by-products to concentrations lower than the regulations require can be possible by lowering the current density to values smaller than 20 mA/cm2. Electrolytic oxidation using BDD or DSA thin film anodes seems to be a sustainable method capable of transforming urine into nutrients, removing organic pollution, and deactivating pathogens

Mineralization of Riluzole by Heterogeneous Fenton Oxidation Using Natural Iron Catalysts

Fenton (H2O2/Fe2+) system is a simple and efficient advanced oxidation technology (AOT) for the treatment of organic micropollutants in water and soil. However, it suffers from some drawbacks including high amount of the catalyst, acid pH requirement, sludge formation and slow regeneration of Fe2+ ions. If these drawbacks are surmounted, Fenton system can be the best choice AOT for the removal of persistent organics from water and soil. In this work, it was attempted to replace the homogeneous catalyst with a heterogeneous natural iron-based catalyst for the decomposition of H2O2 into oxidative radical species, mainly hydroxyl (HO•) and hydroperoxyl radicals (HO2•). The natural iron-based catalyst is hematite-rich (α-Fe2O3) and contains a nonnegligible amount of magnetite (Fe3O4) indicating the coexistence of Fe (III) and Fe(II) species. A pseudo-first order kinetics was determined for the decomposition of H2O2 by the iron-based solid catalyst with a rate constant increasing with the catalyst dose. The catalytic decomposition of H2O2 into hydroxyl radicals in the presence of the natural Fe-based catalyst was confirmed by the hydroxylation of benzoic acid into salicylic acid. The natural Fe-based catalyst/H2O2 system was applied for the degradation of riluzole in water. It was demonstrated that the smaller the particle size of the catalyst, the larger its surface area and the greater its catalytic activity towards H2O2 decomposition into hydroxyl radicals. The degradation of riluzole can occur at all pH levels in the range 3.0–12.0 with a rate and efficiency greater than H2O2 oxidation alone, indicating that the natural Fe-based catalyst can function at any pH without the need to control the pH by the addition of chemicals. An improvement in the efficiency and kinetics of the degradation of riluzole was observed under UV irradiation for both homogeneous and heterogeneous Fenton systems. The results chromatography analysis demonstrate that the degradation of riluzole starts by the opening of the triazole ring by releasing nitrate, sulfate, and fluoride ions. The reuse of the catalyst after heat treatment at 500 °C demonstrated that the heat-treated catalyst retained an efficiency >90% after five cycles. The results confirmed that the natural sources of iron, as a heterogeneous catalyst in a Fenton-like system, is an appropriate replacement of a Fe2+ homogeneous catalyst. The reuse of the heterogeneous catalyst after a heat-treatment represents an additional advantage of using a natural iron-based catalyst in Fenton-like systems

Design technique to mitigate unwanted coupling in densely packed radiating elements of an antenna array for electronic devices and wireless communication systems operating in the millimeter-wave band

An innovative design is presented of a metamaterial inspired antenna array for millimeter-wave band applications where non-mechanical beam-steering is required such as in 5G and 6G communications, automotive and radar systems. In communication systems beam-steering antennas can significantly improve signal-to-noise ratio, spatial directivity, and the efficiency of data transmission. However, in tightly packed arrays the effects of mutual coupling between the radiating elements can severely limit the array’s performance. The proposed antenna array consists of a 3×3 matrix of patch radiators that are tightly packed and interconnected to each other. Rows of radiators are demarcated by a horizontal microstrip transmission-line whose ends are short-circuited to the ground-plane. This technique reduces unwanted surface waves that contribute to undesired coupling. Embedded in the square patch radiators is a rhombus shaped slot that increases the effective aperture of the antenna with no impact on the antenna’s size. As the antenna is excited via a single feedline the edge-to-edge spacing between the radiators and the interconnected feedlines are made such that there is phase coherency at the radiating elements. Measured results show that the effectiveness of the proposed array in simultaneously improving its impedance bandwidth and radiation characteristics. The measured peak gain and radiation efficiency are 13.6 dBi and 89.54%, respectively

Metasurface-Inspired Flexible Wearable MIMO Antenna Array for Wireless Body Area Network Applications and Biomedical Telemetry Devices

This article presents a sub-6GHz ISM-band flexible wearable MIMO antenna array for wireless body area networks (WBANs) and biomedical telemetry devices. The array is based on metasurface inspired technology. The antenna array consists of 2×2 matrix of triangular-shaped radiation elements that were realized on 0.8 mm thick Rogers RT/duroid 5880 substrate. Radiation characteristics of the array are enhanced by isolating the surface current interaction between the individual radiators in the array. This is achieved by inserting an electromagnetic bandgap (EBG) decoupling structure between the radiating elements. The radiating elements were transformed into a metasurface by etching sub-wavelength slots inside them. The periodic arrangement of slots acts like resonant scatterers that manipulate the electromagnetic response of the surface. Results confirm that by employing the decoupling structure and sub-wavelength slots the isolation between the radiators is significantly improved (>34.8 dB). Moreover, there is an improvement in the array’s fractional bandwidth, gain and the radiation efficiency. The optimized array design for operation over 5.0-6.6 GHz has an average gain and efficiency of 10 dBi and 83%, respectively. Results show that the array’s performance is not greatly affected by a certain amount of bending. In fact, the antenna maintains a gain between 8.65-10.5 dBi and the efficiency between 77-83%. The proposed MIMO antenna array is relatively compact, can be easily fabricated on one side of a dielectric material, allows easy integration with RF circuitry, is robust, and maintains its characteristics with some bending. These features make it suitable for various wearable applications and biomedical telemetry devices

Metasurface-inspired flexible wearable MIMO antenna array for wireless body area network applications and biomedical telemetry devices

This article presents a sub-6GHz ISM-band flexible wearable MIMO antenna array for wireless body area networks (WBANs) and biomedical telemetry devices. The array is based on metasurface inspired technology. The antenna array consists of 2 x 2 matrix of triangular-shaped radiation elements that were realized on 0.8 mm thick Rogers RT/duroid 5880 substrate. Radiation characteristics of the array are enhanced by isolating the surface current interaction between the individual radiators in the array. This is achieved by inserting an electromagnetic bandgap (EBG) decoupling structure between the radiating elements. The radiating elements were transformed into a metasurface by etching sub-wavelength slots inside them. The periodic arrangement of slots acts like resonant scatterers that manipulate the electromagnetic response of the surface. Results confirm that by employing the decoupling structure and sub-wavelength slots the isolation between the radiators is significantly improved (>34.8 dB). Moreover, there is an improvement in the array's fractional bandwidth, gain and the radiation efficiency. The optimized array design for operation over 5.0-6.6 GHz has an average gain and efficiency of 10 dBi and 83%, respectively. Results show that the array's performance is not greatly affected by a certain amount of bending. In fact, the antenna maintains a gain between 8.65-10.5 dBi and the efficiency between 77-83%. The proposed MIMO antenna array is relatively compact, can be easily fabricated on one side of a dielectric material, allows easy integration with RF circuitry, is robust, and maintains its characteristics with some bending. These features make it suitable for various wearable applications and biomedical telemetry devices

Study protocol of DIVERGE, the first genetic epidemiological study of major depressive disorder in Pakistan

INTRODUCTION: Globally, 80% of the burdenof major depressive disorder (MDD) pertains to low- and middle-income countries. Research into genetic and environmental risk factors has the potential to uncover disease mechanisms that may contribute to better diagnosis and treatment of mental illness, yet has so far been largely limited to participants with European ancestry from high-income countries. The DIVERGE study was established to help overcome this gap and investigate genetic and environmental risk factors for MDD in Pakistan. METHODS: DIVERGE aims to enrol 9000 cases and 4000 controls in hospitals across the country. Here, we provide the rationale for DIVERGE, describe the study protocol and characterise the sample using data from the first 500cases. Exploratory data analysis is performed to describe demographics, socioeconomic status, environmental risk factors, family history of mental illness and psychopathology. RESULTS AND DISCUSSION: Many participants had severe depression with 74% of patients who experienced multiple depressive episodes. It was a common practice to seek help for mental health struggles from faith healers and religious leaders. Socioeconomic variables reflected the local context with a large proportion of women not having access to any education and the majority of participants reporting no savings. CONCLUSION: DIVERGE is a carefully designed case-control study of MDD in Pakistan that captures diverse risk factors. As the largest genetic study in Pakistan, DIVERGE helps address the severe underrepresentation of people from South Asian countries in genetic as well as psychiatric research

Higher ethical objective (Maqasid al-Shari'ah) augmented framework for Islamic banks : assessing the ethical performance and exploring its determinants.

This study utilises higher objectives postulated in Islamic moral economy or the maqasid al-Shari’ah theoretical framework’s novel approach in evaluating the ethical, social, environmental and financial performance of Islamic banks. Maqasid al-Shari’ah is interpreted as achieving social good as a consequence in addition to well-being and, hence, it goes beyond traditional (voluntary) social responsibility. This study also explores the major determinants that affect maqasid performance as expressed through disclosure analysis. By expanding the traditional maqasid al-Shari’ah,, we develop a comprehensive evaluation framework in the form of a maqasid index, which is subjected to a rigorous disclosure analysis. Furthermore, in identifying the main determinants of the maqasid disclosure performance, panel data analysis is used by including several key variables alongside political and socio-economic environment, ownership structures, and corporate and Shari’ah governance-related factors. The sample includes 33 full-fledged Islamic banks from 12 countries for the period of 2008–2016. The findings show that although during the nine-year period the disclosure of maqasid performance of the sampled Islamic banks has improved, this is still short of ‘best practices’. Through panel data analysis, this study finds that the Muslim population indicator, CEO duality, Shari’ah governance, and leverage variables positively impact the disclosure of maqasid performance. However, the effect of GDP, financial development and human development index of the country, its political and civil rights, institutional ownership, and a higher share of independent directors have an overall negative impact on the maqasid performance. The findings reported in this study identify complex and multi-faceted relations between external market realities, corporate and Shari’ah governance mechanisms, and maqasid performance