Comparing Copper With Stainless Steel as a Stabilizer Layer in Resistive Superconducting Fault Current Limiters

The increasing penetration of renewable energy sources (RESs) into electrical networks offers several interesting opportunities and challenges. One such opportunity is the utilization of DC transmission lines, which can enhance the efficiency and reliability of power transmission. However, DC transmission lines face a challenge in dealing with fault currents due to their high magnitudes and the absence of zero crossing points, characteristics that make it difficult for DC circuit breakers (CBs) to clear faults. Resistive superconducting fault current limiters (r-SFCLs) effectively minimize high magnitude fault currents, allowing DC CBs to operate safely during fault scenarios. The self-triggering feature and fast fault current limitation ability of r-SFCLs also make them particularly suitable for protecting against high DC fault currents. Several studies demonstrated the performance of r-SFCLs with one type of stabilizer layer, most commonly using either copper (Cu) or stainless steel (SS). This paper investigates and compares the performance of an r-SFCL with the two different stabilizer layers, with one case using copper and the other using stainless steel. A thermoelectric r-SFCL model incorporating all composed layers has been developed in Simulink/MATLAB® to investigate the performance of the r-SFCLs with the two different stabilizer layers. The r-SFCLs have been evaluated using different fault scenarios applied to the DC transmission lines of a solar farm. In this model, all r-SFCL layers, excluding the stabilizer layer but including the superconducting, silver, and substrate layers, have been fixed to show the impact of the stabilizer layer materials on the r-SFCL’s performance. This paper illustrates the fault current limiting capability of the r-SFCL, its effect on voltage behavior, its operating temperature, and its sensitivity to the fault location with the two different stabilizer layers. To simulate a range of fault levels and assess the limitation capability of the r-SFCLs, three distinct fault locations have been considered: one located 5 km away from the solar farm, another 15 km away, and a third 25 km away

The experience and impact of stigma in Saudi people with a mood disorder

Abstract Background Stigma plays a powerful role in an individual’s attitude towards mental illness and in their seeking psychiatric and psychological services. Assessing stigma from the perspective of people with mood disorders is important as these disorders have been ranked as major causes of disability. Objectives To determine the extent and impact of stigma experiences in Saudi patients with depression and bipolar disorder, and to examine stigma experiences across cultures. Method Ninety-three individuals with a mood disorder were interviewed at King Saud University Medical City using the Inventory of Stigmatizing Experiences (ISE). Results We detected no significant differences in experiences of stigma or stigma impact in patients with bipolar vs. depressive disorder. However, over 50% of respondents reported trying to hide their mental illness from others to avoiding situations that might cause them to feel stigmatized. In comparison with a Canadian population, the Saudi participants in this study scored significantly lower on the ISE, which might be due to cultural differences. Conclusion More than half of the Saudi participants with a mood disorder reported avoiding situations that might be potentially stigmatizing. There are higher levels of stigma in Canada and Korea than in Saudi Arabia. Our results suggest that cultural differences and family involvement in patient care can significantly impact self-stigmatization. The ISE is a highly reliable instrument across cultures

Optimal Power Flow Analysis With Renewable Energy Resource Uncertainty Using Dwarf Mongoose Optimizer: Case of ADRAR Isolated Electrical Network

Over the last twin decades, significant advancements have occurred in global electricity grids due to the widespread adoption of renewable energy resources (RES). While these sources play an essential role in total generation cost reduction, transmission power loss minimization, and reduction of environmental hazards related to traditional power plants. Still, however, the optimal planning and operation of the power system in the presence RES is considered a primary challenge due to the their stochastic natural and intermittency. One of the most complex and motivating issues in a power system is optimal power flow (OPF), a constrained optimization problem characterized by non-linearity and non-convexity. From these specifications, researchers competed in the past decades to find optimal solutions to stochastic OPF problems while keeping system stability. To tackle this challenge, an effective optimization algorithm which mimics on the foraging behavior of dwarf mongooses’ in the nature is introduced. The objective function considers reserve cost for overestimation and penalty cost for underestimation of intermittent renewable sources. To show the robustness and efficacy of the recommended optimizer, case studies on the customized IEEE 30-bus system and a realistic power system DZA 26-bus (isolated grid) are undertaken. Numerical findings show that the proposed DMOA beats all previous published-results and performs better over a variety of objective functions while finding high-quality optimally viable solutions. The obtained results demonstrate that the DMOA realized exceptional performance for both the test networks, with total generation cost minimized values of 780.982 ${\$}$ /h and 8283.942 US ${\$}$ /h, respectively. These results highlight the precision and robustness of DMOA in effectively addressing various instances of the OPF problem Furthermore, the one-way analysis of variance (ANOVA) test, a statistical approach, was employed to evaluate the superiority of the proposed algorithm and to highlight a certain level of confidence to our study

Identification of on-target mutagenesis during correction of a beta-thalassemia splice mutation in iPS cells with optimised CRISPR/Cas9-double nickase reveals potential safety concerns

Precise and accurate gene correction is crucial for enabling iPSC-based therapies, and Cas9-Nickase based approaches are increasingly considered for in vivo correction of diseases such as beta-thalassemia. Here, we generate footprint-free induced pluripotent stem cells from a patient with a beta-thalassemia mutation (IVSII-1 G > A) and employ a double Cas9nickase-mediated correction strategy combined with a piggyBac transposon-modified donor vector for gene correction. Our approach further aimed to minimize the formation of adjacent single-strand breaks at the targeted allele through the destruction of the binding site for one guide and the use of a synonymous protospacer adjacent motif blocking mutation (canonical PAM sequence 5'-NGG-3' is changed to 5'-NCG-3', where N indicates any nucleobase) for the other guide. We show that this strategy indeed not only permits bi-allelic seamless repair of the beta-globin gene splice site mutation and negligible off-target mutagenesis or re-editing of the targeted allele but also results in unexpected on-target mutagenesis with some guide RNAs (gRNAs) in several targeted clones. This study thus not only validates a framework for seamless gene correction with enhanced specificity and accuracy but also highlights potential safety concerns associated with Cas9-nickase based gene correction. (C) 2018 Author(s)

Analysis of retinal structure and function in cone dystrophy with supernormal rod response

Purpose: To report the clinical and electrophysiological features of cone dystrophy with supernormal rod response (CDSRR). Methods: Retrospective cohort study of 15 unrelated patients (nine males and six females, median age 16, range 5–47 years) diagnosed with CDSRR by clinical examination, full-field electroretinography (ERG) and genetic testing. Observations: History, ophthalmic examination including near vision, color vision and contrast sensitivity assessment, multimodal retinal imaging and ERG. Genetic testing was done for all patients using next-generation sequencing. Results: The rate of consanguinity was 86.7%. Color vision was defective in 56.3%. Near vision was defective in all patients (mean 20/160). Contrast sensitivity was affected in all patients at low contrast of 2.5%. A parafoveal ring of increased autofluorescence imaging was seen in most patients (75%). Supernormal mixed maximal response b-wave was seen bilaterally in 63% of patients (and high normal in 37%). Rod dysfunction with prolonged rod b-wave latency was detected in all. The 30-Hz flicker response was more reduced and delayed compared to the single-flash cone response. A novel homozygous missense variant c.530G>C (p.Cys177Ser) in KCNV2 was detected in one patient, the nonsense homozygous mutation c.427G>T (p.Glu143*) was found in 13 patients, and the nonsense c.159C>G (p.Tyr53*) was found in one patient. Conclusion: This is the largest cohort of CDSRR from a single ethnic background. Rod dysfunction and reduced 30-Hz flicker response were demonstrated in all patients. In contrast to previous descriptions in the literature, a supernormal combined dark-adapted rod-cone ERG was present in the majority of the patients at standard stimulus intensity. Considering the consistent genotype and the demonstration of likely pathogenic genetic variants in all the patients, we argue that the combination of delayed rod b-wave and subnormal flicker response strongly suggests the diagnosis of CDSRR

Boron doped graphene based linear dynamic range photodiode

The boron-doped graphene oxide film was prepared using drop casting/coating technique. The film was coated by hydrothermal method on p-Si substrate and thus Al/p-Si/B-doped GO/Au diode was fabricated. The structural properties of the film was investigated by SEM and EDS techniques. The optoelectronic behavior of the diode was analyzed under various solar light and frequencies. The diode indicates that the forward current is higher that of reverse current with a rectification ratio (RR = I-F/I-R) of 7.30 x 10(4) at dark and +/- 5 V. The diode electronic parameters of the diode were computed from electrical characteristics. An increase in the photocurrent of the diode with solar light intensity indicates the presence of a photoconduction mechanism. The photoconductive and photovoltaic response of the diode were analyzed using photocurrent measurements. The interface state density (N-ss) of the diode was analyzed from conductance technique. The optoelectrical results of the studied device suggest that the diode can be used in optic communications.Scientific Project Unit of Kirklareli University [Klubap 76, Klubap 113]; International Scientific Partnership Program ISPP at King Saud University [0046]This study was supported by Scientific Project Unit of Kirklareli University under project number: Klubap 113. This study was supported by Scientific Project Unit of Kirklareli University under project number: Klubap 76. The authors extend their appreciation to the International Scientific Partnership Program ISPP at King Saud University for funding this research work through ISPP# 0046.WOS:0004496211000142-s2.0-8504813680

Influence of TiO2 and ZrO2 Nanoparticles on Adhesive Bond Strength and Viscosity of Dentin Polymer: A Physical and Chemical Evaluation

The present study aimed to formulate an experimental adhesive (EA) and reinforce it with 5 wt.% titanium dioxide (TiO2) or zirconium oxide (ZrO2) to yield 5% TiO2 and 5% ZrO2 adhesives, respectively, and then analyze the impact of this reinforcement on various mechanical properties of the adhesives. The EA contained a blend of monomers such as bisphenol A glycol dimethacrylate (BisGMA), triethylene glycol dimethacrylate (TEGDMA), 2-hydroxyethyl methacrylate (HEMA), and ethyl 4-dimethylamino benzoate and camphorquinone. The EA included ethyl 4-dimethylamino benzoate and camphorquinone photo-initiators, and diphenyliodonium hexafluorophosphate (DPIHP) was also included to act as an electron initiator. The TiO2 and ZrO2 nanoparticles were incorporated into the EA post-synthesis. To characterize the filler nanoparticles, scanning electron microscopy (SEM) and line-energy dispersive X-ray (EDX) spectroscopy were performed. The adhesives were characterized by analyzing their rheological properties, shear-bond strength (SBS), and interfacial failure types. Further, the resin–dentin interface was also analyzed via SEM. The TiO2 nanoparticles were spherically shaped on the SEM micrographs, while the ZrO2 nanoparticles were seen as non-uniformly shaped agglomerates. The EDX mapping demonstrated the presence of Ti and oxygen for TiO2 and Zr and oxygen for the ZrO2 nanoparticles. Both 5% TiO2 and 5% ZrO2 adhesives revealed decreased viscosity as compared with the EA. The 5% TiO2 adhesive demonstrated higher SBS values for both non-thermocycled (NTC) and thermocycled samples (NTC: 25.35 ± 1.53, TC: 23.89 ± 1.95 MPa), followed by the 5% ZrO2 adhesive group (NTC: 23.10 ± 2.22, TC: 20.72 ± 1.32 MPa). The bulk of the failures (>70%) were of adhesive type in all groups. The SEM analysis of the resin–dentin interface revealed the development of a hybrid layer and resin tags (of variable depth) for the EA and 5% TiO2 groups. However, for the 5% ZrO2 group, the hybrid layer and resin tag establishment appeared compromised. Reinforcement of the EA with TiO2 or ZrO2 caused an increase in the adhesive’s SBS (with the 5% TiO2 group demonstrating the highest values) in comparison with the EA (without nanoparticles). However, both nanoparticle-containing adhesives revealed decreased viscosity compared with the EA (without nanoparticles). Further studies investigating the impact of diverse filler concentrations on the properties of adhesives are suggested

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population