Ain Shams University
  • Cairo, Cairo Governorate, Egypt
Recent publications
Synchronverters are inverters controlled to behave like synchronous generators. However, unbalanced faults or voltage dips may stimulate synchronverters to generate excessive currents and cause instantaneous active and reactive power oscillations at twice the grid's fundamental frequency. Therefore, this paper proposes three fault ride-through (FRT) strategies to remedy these power oscillations and the unlimited current generation during unbalanced faults. The first strategy is based on an instantaneous active and reactive control that significantly reduces power oscillations. The second strategy relies on an average active and reactive control that ensures the delivery of average active and reactive power and maintains sinusoidal phase currents. Finally, the third FRT strategy employs a comprehensive instantaneous active and reactive control to eliminate power oscillations and maintain sinusoidal currents simultaneously. The proposed FRT strategies are equipped with a power management controller that delivers the required active and reactive power during normal operation and limits the inverter's phase currents during faults. Further, the proposed FRT strategies maintain the intrinsic features of synchronverters and ensure seamless activation of the proposed FRT strategies. Comparative results confirm the efficacy of the proposed strategies to reduce power oscillations, limit current generation, maintain synchronverters' intrinsic features, and comply with grid codes.
Essential oils biological activities are more than any time before needed and sought after. From their antimicrobial, antioxidant to antitumor and neuroprotective activities, citrus essential oils are endued with wide health and nutritional benefits, yet their limiting low solubility were a hurdle against their widespread use. Nano emulsions represent an attractive controlled strategy to deliver the lipophilic natural volatile components with ultra-efficacy due to their minute size and stable kinetic properties. Various applications demand the use of Citrus nano emulsions formulations; for instance, sustainable food industry requires safe and powerful antimicrobial agents for long term storage as well as flavoring and coloring agents. In medicine, the low bioavailability of Citrus oil was always a concern and restricted its wide use as a nutraceutical agent despite its proven health profits. This chapter focuses on the different methods applied in the preparation of citrus nano emulsions, their types and properties with a special insight over their role in food, therapy and medicine as well as cosmetics.
Ulcerative colitis (UC) is a chronic relapsing inflammatory disease of the colorectal area that demonstrates a dramatically increasing incidence worldwide. This study provides novel insights into the capacity of the exogenous β-hydroxybutyrate and ketogenic diet (KD) consumption to alleviate dextran sodium sulfate (DSS)-induced UC in rats. Remarkably, both interventions attenuated disease activity and colon weight-to-length ratio, and improved macro and microstructures of the damaged colon. Importantly, both β-hydroxybutyrate and KD curbed the DSS-induced aberrant NLRP3 inflammasome activation as observed in mRNA and protein expression analysis. Additionally, inhibition of the NLRP3/NGSDMD-mediated pyroptosis was detected in response to both regimens. In parallel, these modalities attenuated caspase-1 and its associated consequences of IL-1β and IL-18 overproduction. They also mitigated apoptosis as indicated by the inactivation of caspase-3. The anti-inflammatory effects of BHB and KD were confirmed by the reported decline in the levels of inflammatory markers including MPO, NFκB, IL-6, and TNF-α. Moreover, these interventions exhibited antioxidative properties by reducing ROS production and improving antioxidative enzymes. Their effectiveness in mitigating UC was also evident in the renovation of normal intestinal epithelial barrier function, as shown by correcting the discrepancies in the levels of tight junction proteins ZO-1, OCLN, and CLDN5. Furthermore, their effects on the intestinal microbiota homeostasis were investigated. In terms of autophagy, exogenous β-hydroxybutyrate upregulated BECN-1 and downregulated p62, which may account for its superiority over KD in attenuating colonic damage. In conclusion, this study provides experimental evidence supporting the potential therapeutic use of β-hydroxybutyrate or β-hydroxybutyrate-boosting regimens in UC.
As technology continues to advance, it increases the energy demand. As a result, alternative technologies based on renewable energy are conceivable. Another significant contributor to worldwide energy usage has been cooking. Consequently, switching to solar energy for cooking can solve the current energy issue. The box-style solar cooker is the most straightforward tool for gathering incoming solar radiation and transforming it into heat energy. This study discusses the efficiency and power output as examples of thermal performance parameters used to evaluate various cookers. The efficiency of solar cookers has previously ranged from 17% to 25%; however, this project raises it by 33%. This study uses an automated solar tracking system to improve the performance and efficacy of solar cookers. The four-sided reflector-based box-type solar cooker moves following the sun’s rotation to extract the most energy for heating it and getting it ready for cooking. This test model of the device based on a servo motor is intelligently controlled by an Arduino UNO board.
This work aimed to develop and optimize a simple and rapid method to fabricate a commercially viable catalyst for treating colored, organics-pregnant wastewater effluents for small and medium units requiring simplified fixed installations and medium-skilled labor. This work concentrated on the direct immobilization of CuO onto quartz sand. The crystallography features confirmed complete crystallization in the Tenorite phase. Tenorite grain size showed propagation with annealing temperatures (AT) and slower cooling rates (CR). The SEM confirmed their uniform spherical particles in the submicron range (400–600 nm). A thorough statistical analysis was conducted to infer the optimum synthesis conditions: AT ≈ 400 °C and CR: SC. The fabricated material has demonstrated promising and superior catalytic activity performance for removing organic pollutants. The dynamic optimization plot helped infer the optimum conditions yielding the highest % decolorizing, > 95%, as 0.5 g of 5400Aq catalyst, ≈ 2.0 mL of 3% H2O2, and pH: 2. The dye decays exponentially according to pseudo-first-order kinetics with a half-life time of 3.7 min in case of 5400Aq. The results suggest that the fabricated CuO-coated sand is an effective and commercially viable catalyst, simple, cost-effective, reliable, readily applicable and separable, efficient, enhanced process kinetic, and needs no irradiation.
Graphene quantum dots (GQDs) are a cutting-edge material that has excellent electrical, thermal, and mechanical characteristics, as well as minimal toxicity and powerful photoluminescence. These unique properties give GQDs the ability to be used in different electrical, optical, and optoelectronic applications. GQDs with hexagonal and triangular cuts with armchair and zigzag ends (ATRI, AHEX, ZTRI, and ZHEX) were decorated with different metal oxides such as ZnO, CuO, and TiO2. Metal oxides (MOs) were employed to tune the band gap and electrical properties of GQDs for usage in certain applications. The influence of functionalization on the GQDs electronic properties was examined utilizing HOMO–LUMO orbital distribution and molecular electrostatic potential (MESP) mapping calculations. The model structures were calculated using density functional theory (DFT: B3LYP/ LanL2DZ). The band gap energies of AHEX C42, ZHEX C54, ATRI C60, and ZTRI C46 were found to be 3.508, 2.886, 3.177, and 0.305 eV, respectively. The findings show that addition of MOs increases the total dipole moment (TDM) while decreasing the band gap energy ∆E. The most effective metal MO on GQDs band gap and electronic properties was TiO2, which enhanced the band gap energy ∆E for AHEX C42-TiO2, ZHEX C54-TiO2, ATRI C60-TiO2, and ZTRI C46-TiO2 to 0.391, 0.530, 0.287, and 0.250 eV, respectively. Accordingly, GQDs seem to be excellent for certain applications. Accordingly, GQDs functionalized with ZnO could be used for sensors, due to their increased responsiveness and energy gap variation while GQDs functionalized with TiO2 is excellent to be applied as optoelectronic materials.
Microplastic (MP) pollution in agricultural soils, resulting from the use of plastic mulch, compost, and sewage sludge, jeopardizes the soil microbial populations. However, the effects of MPs on soil chemical properties and microbial communities remain largely unknown. Here, we investigated the effects of different concentration levels (0, 0.1, 1, 3, 5, and 7%; w:w) of low-density polyethylene (LDPE) MPs on the chemical properties and bacterial communities of agricultural soil in an incubation study. The addition of LDPE MPs did not drastically change soil pH (ranging from 8.22 to 8.42). Electrical conductivity increased significantly when the LDPE MP concentrations were between 1 and 7%, whereas the total exchangeable cations (Na⁺, K⁺, Mg²⁺, and Ca²⁺) decreased significantly at higher LDPE MP concentrations (3–7%). The highest available phosphorus content (2.13 mg kg⁻¹) was observed in 0.1% LDPE MP. Bacterial richness (Chao1 and Ace indices) was the lowest at 0.1% LDPE MP, and diversity indices (Shannon and Invsimpson) were higher at 0 and 1% LDPE MP than at other concentrations. The effect of LDPE MP concentrations on bacterial phyla remained unchanged, but the bacterial abundance varied. The relative abundance of Proteobacteria (25.8–33.0%) was the highest in all treatments. The abundance of Acidobacteria (15.8–17.2%) was also high, particularly in the 0, 0.1, and 1% LDPE MPs. With the increase in LDPE MP concentration, the abundance of Actinobacteria gradually increased from 7.80 to 31.8%. Our findings suggest that different MP concentration levels considerably alter soil chemical properties and microbial composition, which may potentially change the ecological functions of soil ecosystems.
Migrant workers have higher rates of mental health problems than non-migrant workers, with Ethiopian migrant workers in the United Arab Emirates appearing to be overrepresented in the psychiatric inpatient population compared with their numbers in the general population. We sought to investigate the pattern of psychiatric inpatient admissions in Ethiopian migrant workers over a 10-year period (2011-2020) in order to highlight demographic and clinical characteristics, and to investigate factors predicting the length of hospital stay. We reported the mean and frequency of demographic and clinical data of Ethiopian psychiatric inpatients at one of the largest governmental hospitals in eastern Abu Dhabi between 2011 and 2020, and investigated factors predicting length of stay in hospital using linear regression. Our results show that Ethiopian expatriates made up 7.9% of all admissions over a 10-year period, had a mean length of hospital stay of almost 20 days, with 98.1% of them being female, 92.8% being domestic workers, 90.1% having a language barrier, 57.4% being single and 55.5.% having one or more recent stressors prior to admission. The most common diagnoses were acute stress reaction (31.6%), psychosis (29.3%), bipolar disorder (14.8%) and adjustment disorder (11.0%). Work-related stress, termination of employment and several clinical factors significantly predicted length of stay in hospital.
Objective: To point out our experience and assess the efficacy and safety of real-time ultrasound-guided central internal jugular vein (IJV) catheterization in the treatment of hemodialysis patients. Methods: This retrospective study comprised 150 patients with end-stage renal disease (ESRD) who had real-time ultrasonography (US)-guided IJV HD catheters placed in our hospital between March 2019 and March 2021. Patients were examined for their demographic data, etiology, site of catheter insertion, type (acute or chronic) of renal failure, technical success, operative time, number of needle punctures, and procedure-related complications. Patients who have had multiple catheter insertions, prior catheterization challenges, poor compliance, obesity, bony deformity, and coagulation disorders were considered at high-operative risk. Results: All patients experienced technical success. In terms of patient clinical features, an insignificant difference was observed between the normal and high-risk groups (p-value > 0.05). Of the 150 catheters, 62 (41.3%) were placed in high-risk patients. The first-attempt success rate was 89.8% for the normal group and 72.5% for the high-risk group (p = 0.006). IJV cannulation took less time in the normal-risk group compared to the highrisk group (21.2 ± 0.09) minutes vs (35.4 ± 0.11) minutes, (p < 0.001). There were no serious complications. During the placing of the catheter in the internal jugular vein, four patients (6.4%) experienced arterial puncture in the high-risk group. Two participants in each group got a small neck hematoma. One patient developed a pneumothorax in the high-risk group, which was managed with an intercostal chest tube insertion. Conclusions: Even in the high-risk group, the real-time US-guided placement of a central catheter into the IJV is associated with a low complication rate and a high success rate. Even under US guidance, experience lowers complication rates. Real-time USguided is recommended to be used routinely during central venous catheter insertion.
New thienopyrimidine derivatives were designed and synthesized as GSK-3β inhibitors based on the structure of active binding site of GSK-3β enzyme. In this study, compounds 6b and 6a were found to be moderate GSK-3β inhibitors with IC50s 10.2 and 17.3 μM, respectively. Molecular docking study was carried out by docking the targeted compounds in the binding site of the GSK-3β enzyme using the MOE program. Moreover, ADME study was performed to predict certain pharmacokinetic properties. The results showed that all synthesized compounds may not be able to penetrate the blood brain barrier; so, the chances of CNS side effects are predicted to be low. CYP1D6 is predicted to be inhibited by compounds (5a, 5d, 6a, 9a and 9b), So drug-drug interactions are expected upon administration of these compounds. Graphical Abstract
Background Failed back surgery syndrome (FBSS) is a constellation of conditions occurring after spine surgeries, characterized by the presence of persistent or recurring low back pain that has a significant impact on patients' quality of life. Neuromodulation in the form of Spinal Cord Stimulation (SCS) is considered an indispensable treatment modality in the management of certain chronic pain conditions and it is showing good results for improvement in pain scores and functional capacity of the FBSS patients. Objectives To assess the change in pain scores, quality of life, and opioid medication intake as an outcome of neuromodulation procedures performed on patients diagnosed with failed back surgery syndrome, and to detect the post‐procedure complications. Methods A prospective observational study was conducted at two university hospitals in Egypt and the U.S.A. during the period from September 2019 to August 2021 for patients who underwent spinal cord stimulation procedures for FBSS with follow‐up period of at least 1 year. Patients who are 18 years old or older diagnosed with FBSS for more than 6 months and treated with spinal cord stimulation with successful trials during this time frame were included in the study. Results Thirty‐four patients were included in this study who had successful SCS trials and underwent permanent implantation of SCS devices with post‐procedure follow‐up period of 12 months. Patients showed a median pain numerical rating scale (NRS) of 7/10 at baseline with a median NRS of 4/10 through the follow‐up period. Basic mobility and daily activity scores assessed by activity measure of post‐acute care (AM‐PAC) showed significant improvement from the mean of 16.87 ± 2.74 at baseline to a mean of 19.97 ± 2.93 through follow‐up. In addition, there was a reduction in opioid medication usage. Post‐procedure complications was of low percentage with the most detected were battery dysfunction in 7 patients and pocket pain in 6 patients. Reoperation was needed in 13 patients with 4 needed just revision and 9 patients required a complete removal of the device. Conclusion Spinal cord stimulation is an effective modality of treatment for cases of failed back surgery syndrome with a statistically significant reduction in pain scores and a significant improvement in quality of life. Also, it achieves a recognizable reduction in opioid analgesic medications, with a reliable safety profile as detected with the recorded post‐procedure complications. However, randomized controlled trials with more patients and long‐term follow‐up are highly recommended.
Numerous studies revealed that Chlorella vulgaris and orange peels are potential sources for many valuable compounds such as flavonoids, which are natural polyphenols with antioxidant capacities that trigger oxidative stress via suppressing ROS levels. Thus, this study was designed to investigate their radioprotective efficiency either alone or in combination as natural food supplements. Sixty‐four male Albino rats were divided into eight groups ( n = 8) as follows: control, orange peel (10% in diet), C. vulgaris (1% in diet), orange peel + C. vulgaris , gamma irradiated (2Gy twice per week up to 8Gy), orange peel + gamma irradiation, C. vulgaris + gamma irradiation, and orange peel + C. vulgaris + gamma irradiation. After the experiment, blood serums were collected for biochemical analysis, whole bloods were collected for blood picture, bone marrows were collected for GSH, MDA, TGF‐β, NOX2 and NOX4, and liver tissues were collected for histopathological evaluation. Current study revealed that exposure to gamma irradiation induced a significant disturbance in liver function markers (ALT and AST), kidney function markers (urea and creatinine), cholesterol and triglycerides levels in serum. In addition, a significant decrease in WBCs, RBCs, PLT, and Hb in blood of irradiated rats. Moreover, a significant elevation in TGF‐β, NOX2, NOX4 activities, and MDA level, while showed a marked decrease in GSH concentration. Furthermore, hepatic inflammation appeared in the histopathological examination. Orange peels or C. vulgaris treatments showed acceptable amelioration in all measured parameters, combination between orange peels and C. vulgaris showed statistically significant additive amelioration in radiation induced disturbance.
This work examines the impact of an unchanged longitudinal electric field and the ambient gas on the EHD instability of an Oldroyd-B fluid in a vertical cylinder, where the system is immersed in permeable media. In order to explore the possible subject uses in thermo-fluid systems, numerous experimental and theoretical types of research on the subject are conducted. The main factors influencing the dispersion and stability configurations are represented by the energy and concentration equations. The linear Boussinesq approximating framework is recommended for further convenience. A huge growth in numerous physical and technical implications is what motivated this study. Using the standard normal modes of examination, the characteristics of velocity fields, temperature, and concentration are analyzed. The conventional stability results in a non-dimensional convoluted transcendental dispersion connection between the non-dimensional growth rate and all other physical parameters. The Maranogoni phenomenon, in which temperature and concentration distributions affect surface tension, has been addressed. It is observed that the intense electric field, the Prandtl numeral, the Lewis numeral, and the Lewis numeral velocity ratio have a stabilizing influence. As opposed to the Weber numeral, the Ohnesorge numeral, and the density ratio have a destabilizing influence.
This study investigates the influence of tip speed ratio (TSR) as maximum power point tracking (MPPT) technique on energy conversion for wind-powered electric vehicles (EVs) charging stations. The data for 14 different models of (EVs) as well as the energy demand profile for El Sherouk city in new Cairo, Egypt, is used in the study. Those vehicles represent the models that are most likely to be used according to the nature of the Egyptian market from economic and technological concerns. This includes range, battery capacity, battery technology and charging methods. charging can be in the form of fast DC, three phases which are suitable for commercial charging stations or a single phase charging suitable for residential use. A simulation is done using MATLAB/Simulink for a wind turbine Permanent Magnet Synchronous Generator (PMSG) system including TSR MPPT algorithm. The energy output is compared with and without implementing the MPPT algorithms to measure the difference in energy. The system simulation optimized by the TSR MPPT algorithm shows an increase in the energy yield by 41.68%. The economic analysis showed a 30% reduction in the levelized cost of energy while utilizing the TSR concerning a bare system without an MPPT algorithm.
Correction for ‘Highly selective optical sensor N/S-doped carbon quantum dots (CQDs) for the assessment of human chorionic gonadotropin β-hCG in the serum of breast and prostate cancer patients’ by Yasmeen M. AlZahrani et al., RSC Adv., 2023, 13, 21318–21326,
Covid-19 crisis did hit many socio-economic aspects in the whole world. In the scientific research, the problem is getting even worse, since most of materials and consumable are allocated to the health sector. Many research laboratories around the world have big delay in receiving their purchases to accomplish their research projects. In the developing countries, the situation is much more difficult, since most of the funding resources are directed to the Covid-19 crisis and there is a notable increase in reagents’ prices. Therefore, the aim of the present study is to make a homemade reagents for RNA purification from eukaryotic cells/tissues. The homemade phenol-based RNA extraction reagents were prepared using saturated phenol pH 4.3 (adjusted by 0.5 M citrate buffer) and guanidine thiocyanate. To validate the phenol-based reagent, RNA was purified from different biological samples (cell line, tissues, and fungi) using homemade phenol-based versus a commercial one. Concentration of RNA samples extracted from the same number of cells were compared to assess the homemade preparation of phenol-based reagent. In conclusion, homemade phenol-based reagent is cost effective and comparable to the commercial one. Using homemade phenol-based, RNA extraction was successfully purified from different biological sources.
Background The treatment of vitiligo can be challenging and depends on several factors such as the subtype, disease activity, vitiligo extent, and treatment goals. Vitiligo usually requires a long‐term approach. To improve the management of vitiligo worldwide, a clear and up‐to‐date guide based on international consensus with uniform stepwise recommendations is needed. Objectives To reach an international consensus on the nomenclature and to develop a management algorithm for the diagnosis, assessment, and treatment of vitiligo. Methods In this consensus statement, a consortium of 42 international vitiligo experts and four patient representatives participated in online and live meetings to develop a consensus management strategy for vitiligo. At least two vitiligo experts summarized the evidence of topics included in the algorithms. A survey was utilized to resolve remaining issues among a core group of eight experts. Subsequently, the unanimous recommendations were finalized and validated based on further input from the entire group during two live meetings. Results The algorithms highlight the importance of shared decision‐making. Dermatologists are encouraged to provide patients with detailed explanations of the prognosis and expected therapeutic outcomes based on clinical examination. The treatment goal should be discussed and clearly emphasized to patients given the different approaches for disease stabilization and repigmentation. The evaluation of disease activity remains a cornerstone in the tailor‐made approach to vitiligo patients. Conclusions These new treatment algorithms are intended to guide clinical decision‐making in clinical practice. Promising novel therapies for vitiligo are on the horizon, further highlighting the need for reliable outcome measurement instruments and greater emphasis on shared decision‐making.
The pursuit of low-cost manufacturing of newly effective pigments is a pressing economic need. Thus, in this work, low-cost ZnFe 2 O 4 spinel nanoparticles (ZF-NPs) with an average diameter of 20 nm were successfully synthesized using a simple sol–gel method, which can be extended for large-scale fabrication of a reddish nano pigment. TGA/DTA, XRD, DRS, HRTEM, and SEM/EDX investigations were used to characterize the as-prepared product. The color of synthesized NPs was studied using CIE L * a * b * colorimetric method with color coordinates of L * = 41.7, a * = 72.2, and b * = 48.8. The newly developed pigment was examined to be superior to the traditional pigment (M6001/Fe 2 O 3 : L * = 30.4, a * = 42.16, and b * = 45.7). After that, the synthesized nano pigment was integrated into both ink and paint formulations as a multifunctional coating. The inclusion of synthesized nano pigment in metal coating printing ink formulation was done to produce a good alternative and cost-effective substitute for the commercially available pigment used in the inks industry. Also, the effect of the fabricated nanoparticles on corrosion resistance and thermal stability of epoxy-based paint formulations was evaluated using different standard tests. Therefore, the ZnFe 2 O 4 pigment should be applied as a highly efficient inorganic nano pigment.
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21,777 members
Yasser Mohammed Sabry
  • Department of Electronics and Electrical Communication Engineering
Ahmed Shaker
  • Department of Engineering Physics and Mathematics
Wael M. El-Sayed
  • Department of Zoology
Ashraf Fawzy Nabhan
  • Department of Obstetrics and Gynecology
Al-Khalifa Al-Maamoun, Abbassia, 11566, Cairo, Cairo Governorate, Egypt
Head of institution
Prof. Dr. Mahmoud El-Meteini