Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most widespread neurological disorders (NDs) characterized by degeneration of cognitive and motor functions due to malfunction and ...loss of neurons in the central nervous system (CNS). Numerous evidences have established the role of neuroinflammation in the AD and PD pathology. The inflammatory components such as microglia, astrocytes, complement system and cytokines are linked to neuroinflammation in the CNS. More specifically, cytokines have been found to play a central role in the neuroinflammation of AD and PD. A number of studies have demonstrated abnormally elevated levels of inflammatory cytokines such as interleukin-1β (IL-1β) and tumor necrosis factor (TNF) in AD and PD patients. Activated microglial cells have been shown to be involved in the secretion of pro-inflammatory cytokines such as IL-1, IL-6, TNF-α and transforming growth factor-β, thereby contributing towards the progress of NDs. In addition, studies on AD pathogenesis have demonstrated that microglia produce beta-amyloid protein (Aβ), which by itself is pro-inflammatory and causes activation of several inflammatory components. Similarly, chronic inflammation caused by microglial cells is the fundamental process involved in the destruction of neurons associated with dopamine (DA)-production in the brain of PD patients. Hence, there is a need to explore the key inflammatory components in AD and PD pathogenesis in order to fully understand the root cause and establish a substantial link between these two disorders. Such knowledge will help in better management and treatment of AD and PD.
Evaluation of coronary artery calcium score (CACS) at multiple low and high cutoff values for the detection of significant coronary stenosis at two different cutoffs (50 and 70%) in a large number of ...symptomatic patients was not investigated previously in one study. This study aims to investigate if there are a correlation and statistical significance between different CACS cutoffs and the severity of coronary artery stenosis by coronary CT angiography (CCTA) in symptomatic patients.
This is a retrospective study that included all symptomatic patients who had CCTA in a tertiary care hospital over a period of 7 years.
CCTA of 502 patients was evaluated (406 included, mean age 56.2 years); 230 were males (56.7%). The prevalence of stenosis at any percentage was 53.7%, ≥50% was 26.6% and ≥70% was 12.3%. The mean CACS was 84.5 (range 0-1860), for males was 124.5 and for females was 32.1. Patients with CACS of zero (59%) and CACS of ≥1 (41%) had a mean stenosis of 8.9% (range 0-75%) and 52.6% (range 0-100%), respectively. All patients with a CACS of ≥250 were found to have ≥50% stenosis (100% specificity and positive predictive value, 35.2% sensitivity, 81% negative predictive value and 82.6% accuracy). The percentage of stenosis increased as CACS increased with strong statistical significance (P value < 0.0001) and a positive correlation (r = 0.58).
CACS is a valuable diagnostic tool to predict the severity of coronary artery stenosis. A cutoff value of 250 confirmed the presence of at least 50% stenosis in symptomatic patients.
The integration of photovoltaic (PV) into electric power systems has been widely explored and adopted to address the problems associated with the depletion of fossil fuels and the release of ...greenhouse gases. PV panels convert sunlight into electricity, minimizing the reliance on fossil fuels and mitigating environmental pollution. It is crucial to optimally utilize the PV power in the system; hence maximum power point tracking (MPPT) algorithms have been developed to ensure optimal performance of grid-connected PV systems at the maximum power point (MPP) despite changes in weather conditions. Moreover, deep reinforcement learning (DRL) developments provide a promising approach for optimizing grid-connected PV systems, replacing the conventional proportional-integral-derivative (PID) controllers. However, there is limited research evaluating the efficiency of these systems using DRL techniques. This paper proposes a new dandelion optimizer (DO)-based DRL for MPPT of grid-connected photovoltaic systems and evaluates the proposed method for a 100-MW PV plant connected to a 33-kV distribution system. The proposed DRL technique uses proximal policy optimization (PPO) and deep deterministic policy gradient (DDPG) algorithms for continuous states and discrete or continuous action spaces to adjust the PV-measured voltage based on a reference one produced via DO-PPO and DO-DDPG methods. To test the effectiveness and practicality of the introduced methods, simulations were conducted using actual input data of a 100 MW PV plant connected to a 33-kV distribution system for typical days in summer and winter seasons using MATLAB/Simulink software. The proposed implemented methods were evaluated by comparing their simulation results with other techniques: DO-PID, particle swarm optimization (PSO), and incremental conductance (InC-PI). The findings revealed that the efficiencies of the DC-DC boost and the voltage source converters using the introduced methods were 84.25%- 85.90%, and 78.33%- 81.10% on a summer day while they were 92.77%- 95% and 86.70%- 89.50% on a winter day, respectively, which proves that these methods were efficient and effective, indicating their promising potential for future applications.
In electrical distribution systems, shunt capacitors are installed in order to reduce system losses, to enhance the voltage profile, and to free up system capacity. Nevertheless, the installation of ...shunt capacitors in distribution systems with distorted waveforms will magnify the distortion level of harmonics if they are not set at appropriate locations relative to the harmonics. This paper proposes a hybrid method to determine the placement and sizing of shunt capacitors in distorted radial distribution systems, taking into account the presence of harmonic distortion with consideration of ambient temperature effects, (this technique consists of the fuzzy expert system approach and the Genetic Algorithm method). This hybrid technique is applied to an IEEE 34-bus radial standard distribution system as well as a real distribution system in the Saudi Electricity Company. The simulation results show that harmonic distortion considerably reduces and the efficiency of distribution systems increases with a reduction in power loss and enhancement of voltage regulation.
While ionic liquids and deep eutectic solvents, DESs, have been extensively used for natural product extraction relatively little is known about the factors affecting extraction efficiency. In this ...study, 7 simple solutes are extracted into 4 DESs at two temperatures and the thermodynamics of phase transfer are determined. It was found that solutes which are able to form hydrogen bond are more successfully extracted into the DES phase from cyclohexane. For less polar solutes, the extracting DES has a more pronounced effect on extraction efficiency with liquids of a lower surface tension being more effective. With polar solutes the effect of the DES is less pronounced. It is shown that the Gibbs energy of extraction is proportional to the p
K
a
of the solute demonstrating the importance of hydrogen bonding in solute partition. The study was extended to 5 phenolic compounds commonly found in olive oil and again the extraction efficiency was shown to be related to the solute p
K
a
. The green metrics for the extraction of a range of solutes were determined and shown in some cases to be superior to molecular solvents. The energy consumption of extraction was shown to be comparatively small even when mechanically assisted.
While ionic liquids and deep eutectic solvents, DESs, have been extensively used for natural product extraction relatively little is known about the factors affecting extraction efficiency.
An effective maximum power point tracking (MPPT) technique plays a crucial role in improving the efficiency and performance of grid-connected renewable energy sources (RESs). This paper uses the ...African Vulture Optimization Algorithm (AVOA), a metaheuristic technique inspired by nature, to tune the proportional–integral (PI)-based MPPT controllers for hybrid RESs of solar photovoltaic (PV) and wind systems, as well as the PI controllers in a storage system that are used to smooth the output fluctuations of those RESs in a hybrid system. The performance of the AVOA is compared with that of the widely used the particle swarm optimization (PSO) technique, which is commonly acknowledged as the foundation of swarm intelligence. As a result, this technique is introduced in this study to draw a comparison. It is observed that the proposed algorithm outperformed the PSO algorithm in terms of the tracking speed, robustness, and best convergence to the minimum value. A MATLAB/Simulink model was built, and optimization and simulation for the proposed system were carried out to verify the introduced algorithms. In conclusion, the optimization and simulation results showed that the AVOA is a promising method for solving a variety of engineering problems.
Distributed grid-connected photovoltaic (PV) generation explores several methods that produce energy at or near the point of consumption, with the aim of reducing electricity losses among ...transmission networks. Consequently, home on-grid PV applications have garnered increased interest from both scientific researchers and industry professionals over the last decade. Nevertheless, the growing installation of intermittent nature residential PV systems (R-PV) in low-voltage distribution networks is leading to more cautious considerations of technology limitations and PV design challenges. This conservative perspective arises from the standpoint of grid quality and security, ultimately resulting in the revocation of PV connection authorization. Hence, the design of R-PV systems should consider not only the specifications of the PV panels and load profiles but also the characteristics and requirements of the connected power grid. This project therefore seeks to enhance the design considerations of grid-connected PV systems, in order to help the end-users meet the grid codes set out by the Saudi Electricity Regulatory Authority (SERA). Since the maximum amount of generated power is essential for PV system optimization, the ratio of grid strength to maximum transmitted power was employed to ascertain the suitable capacity of the PV system, while the assessment of PV power output was utilized to specify the system size. Furthermore, a battery energy storage system (BESS) with a small size (~10% of the PV capacity) is employed to enhance the PV power quality for a dependable grid interconnection. The BESS is equipped with a versatile power controller in order to achieve the designed objectives. The obtained results show an essential advancement in terms of power quality and reliability at the customer’s connection point. Moreover, with the design assessment process, the low-voltage ride-through (LVRT) and power factor requirements can be met, in addition to the total harmonic distortion (THD) and frequency transient limitations. The proposed solution assists end-users in efficiently designing their own R-PV systems while ensuring quality and sustainability for authorized grid interconnection.
The inhibition of cholinesterase enzymes is one of the promising strategies to manage several neurological disorders that include Alzheimer's disease (AD).
In the current article, we estimated the ...potential inhibition of acetyl cholinesterase (AChE) by phenserine using slightly modified Ellman assay. To find out the binding interactions of phenserine with the catalytic site of AChE, a molecular docking study was also performed.
Phenserine was found to inhibit Electrophorus electricus AChE in a dose-dependent manner with an IC50 value of 0.013 µM. The kinetic analyses indicate that phenserine inhibits AChE in a mixed type manner (competitive and uncompetitive) with Ki values of 0.39 μmole/l and 0.21 µmole/l, respectively. On the other hand, Km and Vmax values were found to be 0.17 µM and 0.39 µM, respectively. The molecular docking studies indicate efficient binding of phenserine through 6 hydrogen bonds, 4 pi-alkyl interactions, and 1 pi-pi interaction within the AChE catalytic pocket.
Results of our computational and kinetics studies indicated a mixed type inhibition by phenserine at AChE catalytic site.
This paper deals with minimax fractional programs whose objective functions are the maximum of finite ratios of convex functions, with arbitrary convex constraints set. For such problems, ...Dinkelbach-type algorithms fail to work since the parametric subproblems may be nonconvex, whereas the latter need a global optimal solution of these subproblems. We give necessary optimality conditions for such problems, by means of convex analysis tools. We then propose a method, based on solving approximately a sequence of parametric convex problems, which acts as dc (difference of convex functions) algorithm, if the parameter is positive and as Dinkelbach algorithm if not. We show that every cluster point of the sequence of optimal solutions of these subproblems satisfies necessary optimality conditions of KKT criticality type, that are also of Clarke stationarity type. Finally we end with some numerical tests to illustrate the behaviour of the algorithm.
Phthalates are a class of high volume production chemicals used as plasticizers for household and industrial use. Several members of this chemical family have endocrine disrupting activity. Owing to ...ubiquitous environmental distribution and exposure of human population at all stages of life, phthalate contamination is a continuous global public health problem. Clinical and experimental studies have indicated that several phthalates are associated with adverse effects on development and function of human and animal systems especially the reproductive system and exposures during pregnancy and early childhood are by far of utmost concern. Sex hormone-binding globulin (SHBG) is a plasma carrier protein that binds androgens and estrogens and represents a potential target for phthalate endocrine disruptor function in the body. In the present study, the binding mechanism of the nine phthalates i.e. DMP, DBP, DIBP, BBP, DNHP, DEHP, DNOP, DINP, DIDP with human SHBG was delineated by molecular docking simulation. Docking complexes of the nine phthalates displayed interactions with 15-31 amino acid residues of SHBG and a commonality of 55-95% interacting residues between natural ligand of SHBG, dihydrotestosterone, and the nine phthalate compounds was observed. The binding affinity values were more negative for long chain phthalates DEHP, DNOP, DINP, and DIDP compared to short chain phthalates such as DMP and DBP. The Dock score and Glide score values were also higher for long chain phthalates compared to short chain phthalates. Hence, overlapping of interacting amino acid residues between phthalate compounds and natural ligand, dihydrotestosterone, suggested potential disrupting activity of phthalates in the endocrine homeostasis function of SHBG, with long chain phthalates expected to be more potent than the short chain phthalates.
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