66 research outputs found

    Cuckoo search algorithm based for tunning both PI and FOPID controllers for the DFIG-Wind energy conversion system

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    Wind Energy has received great attention in this century. It influences the new power systems, adding new challenges to the power system expansion problem. Nowadays, double feed induction generator (DFIG) wind turbines are used majorly in wind farms, due to their advantages over other types. Therefore, the analysis of the system using this type has become very important. In this paper, a wind turbine modelling was introduced with suggested controllers, in order to enhance the system response, with respect to both pitch control and maximum output power. Cuckoo search algorithm (CSA), a meta-heuristic optimization technique, was implemented to determine the gains of a proportional-integral (PI) controller and fractional order proportional-integral-derivative (FOPID) controller to optimize the system, which considered three control loops: pitch, rotor-side converter, and grid-side converter control loop. Simulation results were determined using MATLAB/Simulink. The comparative analysis of the results showed that the PI Controller gave the simplest and the best response in case of the pitch and rotor-side control loops while the FOPID was the best when applied to the grid-side control loop. Based on the results and discussion, a suggestion of using a compination of each controller was introduced

    Switched capacitor based multi-level boost inverter for smart grid applications

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    To link DC power sources to an AC grid, converters are needed. Inverters are the power electronic devices, which are used for this purpose. Conventional inverters employ harmonic filters and transformers that are lossy and expensive. Multilevel inverters (MLIs) are an alternative to conventional ones, proposing reduced total harmonic distortion (THD), increased range of control, and inductor-less design. They generate a stepped waveform, with close similarity to a sine wave. Many distributed sources may be employed in a smart grid. If those sources have minimal THD, the filtering process could be reduced at the point of common coupling. This paper presents two switched capacitor based MLIs, proposing boost capability and low THD. Inverters have inherent charge balancing capability, which eliminates the need for auxiliary circuits and voltage sensors. Inverters switches are modulated using phase opposition disposition pulse-width modulation (PODPWM) method that ease the balancing of the voltage and decrease the losses of switching. Designs were verified by simulation and the output waveforms were introduced

    DNA-binding and anticancer activity of binuclear gold(I) alkynyl complexes with a phenanthrenyl bridging ligand

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    3,6-Diethynyl-9,10-diethoxyphenanthrene (4) was synthesized from phenanthrene and employed in the synthesis of the binuclear gold(I) alkynyl complexes (R3P)Au(C≡C-3-[C14H6-9,10-diethoxy]-6-C≡C)Au(PR3) (R = Ph (5a), Cy (5b)). The diyne 4 and complexes 5a and 5b were characterized by NMR spectroscopy, mass spectrometry, and elemental analysis. UV-Vis spectroscopy studies of the metal complexes and precursor diyne show strong π → π* transitions in the near UV region that red shift by ca. 50 nm upon coordination at the gold centers. The emission spectrum of 4 shows an intense fluorescence band centered at 420 nm which red shifts, slightly upon coordination of 4 to gold. Binding studies of 4, 5a, and 5b against calf thymus DNA were carried out, revealing that 4, 5a, and 5b have ≥40% stronger binding affinities than the commonly used intercalating agent ethidium bromide. The molecular docking scores of 4, 5a, and 5b with B-DNA suggest a similar trend in behavior to that observed in the DNA-binding study. Unlike the ligand 4, promising anticancer properties for 5a and 5b were observed against several cell lines; the DNA binding capability of the precursor alkyne was maintained, and its anticancer efficacy enhanced by the gold centers. Such phenanthrenyl complexes could be promising candidates in certain biological applications because the two components (phenanthrenyl bridge and metal centers) can be altered independently to improve the targeting of the complex, as well as the biological and physicochemical properties.This project was funded by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Saudi Arabia under grant no. (KEP-44-130-40). The authors, therefore, acknowledge with thanks DSR technical and financial support

    The potential anticancer activities of platinum(II) complexes with tridentate N'N'N' pincer ligands

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    519-530Treatment of cis/trans-[PtCl2(N≡CR)2] 1 (R = CH3 (1a), C2H5 (1b), C6H5 (1c), CH2C6H4(p-CH3) (1d)) with 1,3-diiminoisoindoline 2 gives access to the corresponding symmetrical (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato) platinum(II) complexes [PtCl{NH=C(R)N=C(C6H4)NC=NC(R)=NH}] 3a-d, in good yields (65–77%). The compounds 3a-d have been characterized by IR, 1H, 13C and DEPT-135 NMR spectroscopies, ESI-MS and elemental analyses. GIAO/DFT studies have been performed to confirm the molecular structure of the platinum(II)-pincer 3d by comparing the experimental and theoretical 1H and 13C NMR chemical shifts, and it has shown good correlations between experimental and calculated chemical shifts for proton and carbon with correlation coefficients of 0.9947 and 0.9968, respectively. Molecular electrostatic potential is used to investigate the nucleophilic or electrophilic regions in the molecule 3d. The antimicrobial activities of compounds 3a-d are determined against different bacterial pathogens and yeasts. No toxicity is recorded against Artemia saline as a test organism for 3a-c, while moderate toxicity is found for 3d at 0.62 µM. Comparable antitumor activities are found for 3a-d against human colon HCT116 and human breast (MCF-7) cancer cell lines. The complexes 3a-d have shown good binding affinities to ct-DNA in the range of 6.00´105 to 8.33´105 and the conducted molecular docking studies suggest an intercalation mode of binding with DNA by the isoindole fragment of the ligands. Overall, this class of tridentate ligands have shown good potential in designing platinum(II) complexes with promising biological and anticancer activities. Moreover, the presence of the side chains on the ligands provides great design flexibility by introducing some chemical and/or physical characteristics

    Stop Turning a Blind Eye: Tobacco Smoking Among Egyptian Patients With Schizophrenia

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    Background: Patients with schizophrenia have considerably higher rates of mortality than general population. Multiple factors may play a role in this. Despite being a major preventable cause of death, smoking is usually overlooked when dealing with patients with schizophrenia. Understanding the pattern of smoking, its severity, and the reasons to quit might be helpful in managing patients with schizophrenia and decreasing the mortality gap.Subjects and Methods: The study included smokers divided into two groups; the first included 346 patients with schizophrenia while the second group had 150 smokers with no mental illness. Both groups were assessed and compared regarding sociodemographic variables, pattern of smoking, severity of nicotine dependence, and motivation to quit smoking.Results: Earlier age of starting to smoke, higher number of cigarettes per day, and lower dependency scores were noted in patients with Schizophrenia. Positive correlation was found between positive symptoms and severity of dependence. Specific positive symptoms were correlated to number of cigarettes per day and time before first cigarette. Patients with Schizophrenia showed a significant difference in intrinsic reasons to quit (health concerns and self-control), which were also positively correlated to their positive symptoms score. Linear regression analysis for predictors of FTND score revealed that only age, sex, and schizophrenia were significant predictors of FTND score.Conclusion: Patients with schizophrenia smoke at earlier ages and smoke more cigarettes per day, yet, have less severe dependence than non-schizophrenic counterparts. Positive symptoms play a role in their smoking pattern and severity. Health concerns and self-control are their main motives to quit smoking

    DNA-Binding Capabilities and Anticancer Activities of Ruthenium(II) Cymene Complexes with (Poly)cyclic Aromatic Diamine Ligands

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    Ruthenium(II) arene complexes of the general formula [RuCl(η6-p-cymene)(diamine)]PF6 (diamine = 1,2-diaminobenzene (1), 2,3-diaminonaphthalene (2), 9,10-diaminophenanthrene (3), 2,3-diaminophenazine (4), and 1,2-diaminoanthraquinone (5) were synthesized. Chloro/aqua exchange was evaluated experimentally for complexes 1 and 2. The exchange process was investigated theoretically for all complexes, revealing relatively fast exchange with no significant influence from the polycyclic aromatic diamines. The calf thymus DNA (CT-DNA) binding of the complexes increased dramatically upon extending the aromatic component of the diamines, as evaluated by changes in absorption spectra upon titration with different concentrations of CT-DNA. An intercalation binding mode was established for the complexes using the increase in the relative viscosity of the CT-DNA following addition of complexes 1 and 2. Theoretical studies showed strong preference for replacement of water by guanine for all the complexes, and relatively strong Ru-Nguanine bonds. The plane of the aromatic systems can assume angles that support non-classical interactions with the DNA and covalent binding, leading to higher binding affinities. The ruthenium arenes illustrated in this study have promising anticancer activities, with the half maximal inhibitory concentration (IC50) values comparable to or better than cisplatin against three cell lines.This project was funded by the Deanship of Scientific Research (DSR), King Abdulaziz University, Jeddah, Saudi Arabia under grant no. (KEP-60-130-38)

    The potential anticancer activities of platinum(II) complexes with tridentate N'N'N' pincer ligands

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    Treatment of cis/trans-[PtCl2(N≡CR)2] 1 (R = CH3 (1a), C2H5 (1b), C6H5 (1c), CH2C6H4(p-CH3) (1d)) with 1,3-diiminoisoindoline 2 gives access to the corresponding symmetrical (1,3,5,7,9-pentaazanona-1,3,6,8-tetraenato) platinum(II) complexes [PtCl{NH=C(R)N=C(C6H4)NC=NC(R)=NH}] 3a-d, in good yields (65–77%). The compounds 3a-d have been characterized by IR, 1H, 13C and DEPT-135 NMR spectroscopies, ESI-MS and elemental analyses. GIAO/DFT studies have been performed to confirm the molecular structure of the platinum(II)-pincer 3d by comparing the experimental and theoretical 1H and 13C NMR chemical shifts, and it has shown good correlations between experimental and calculated chemical shifts for proton and carbon with correlation coefficients of 0.9947 and 0.9968, respectively. Molecular electrostatic potential is used to investigate the nucleophilic or electrophilic regions in the molecule 3d. The antimicrobial activities of compounds 3a-d are determined against different bacterial pathogens and yeasts. No toxicity is recorded against Artemia saline as a test organism for 3a-c, while moderate toxicity is found for 3d at 0.62 µM. Comparable antitumor activities are found for 3a-d against human colon HCT116 and human breast (MCF-7) cancer cell lines. The complexes 3a-d have shown good binding affinities to ct-DNA in the range of 6.00´105 to 8.33´105 and the conducted molecular docking studies suggest an intercalation mode of binding with DNA by the isoindole fragment of the ligands. Overall, this class of tridentate ligands have shown good potential in designing platinum(II) complexes with promising biological and anticancer activities. Moreover, the presence of the side chains on the ligands provides great design flexibility by introducing some chemical and/or physical characteristics

    Computational approaches for the design of novel anticancer compounds based on pyrazolo[3,4-d]pyrimidine derivatives as trap1 inhibitor

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    In the present in-silico study, various computational techniques were applied to determine potent compounds against TRAP1 kinase. The pharmacophore hypothesis DHHRR_1 consists of important features required for activity. The 3D QSAR study showed a statistically significant model with R2 = 0.96 and Q2 = 0.57. Leave one out (LOO) cross-validation (R2 CV = 0.58) was used to validate the QSAR model. The molecular docking study showed maximum XP docking scores (−11.265, −10.532, −10.422, −10.827, −10.753 kcal/mol) for potent pyrazole analogs (42, 46, 49, 56, 43), respectively, with significant interactions with amino acid residues (ASP 594, CYS 532, PHE 583, SER 536) against TRAP1 kinase receptors (PDB ID: 5Y3N). Furthermore, the docking results were validated using the 100 ns MD simulations performed for the selected five docked complexes. The selected inhibitors showed relatively higher binding affinities than the TRAP1 inhibitor molecules present in the literature. The ZINC database was used for a virtual screening study that screened ZINC05297837, ZINC05434822, and ZINC72286418, which showed similar binding interactions to those shown by potent ligands. Absorption, distribution, metabolism, and excretion (ADME) analysis showed noticeable results. The results of the study may be helpful for the further development of potent TRAP1 inhibitors

    X-ray crystal structure, NMR, DFT investigations, pharmaco-kinetic, and toxicity of sarcotrocheliol: A pyrane-based cemranoids of marine origin

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    69-80One of a recently discovered marine origin cembranoids has been studied experimentally and theoretically to obtain its thorough structural, electronic, spectroscopic, and biochemical activity. The exact molecular structure of sarcotrocheliol (C20H34O2) 1 has been determined for the first time using a single crystal X-ray diffraction analysis. Crystallography shows that the molecule is crystalline as an orthorhombic, space group of P212121, with a = 9.20(4) Å, b = 10.80(4) Å, c = 19.99(9) Å. 1H, 13C and DEPT-135 NMR measurements of sarcotrocheliol1have been measured in four different deuterated solvents: CDCl3, CD3CN, MeOH-d4 and DMSO-d6. Theoretical calculations have been performed to find the main structural and electronic properties of the compound and matched with the experimental properties. The density functional theory (DFT) method at B3LYP/6-311++G(d,p) level of theory has been used for all computed properties. Vibrational frequencies have been determined using DFT calculations and compared with the experimental values. Computed chemical shifts in the NMR have been determined by the GIAO method. The correlation coefficients between the calculated and experimental NMR chemical shifts have been found to be 0.92 and 0.998 for 1H and 13C NMR, respectively. Physicochemical parameters of the compound versus reference drugs have been done. The isolated compound meets the main criteria of the employed rules indicating a drug-like character. The molecular docking studies have been performed for the compound toward the breast and prostate cancers
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