Voltage Profile and Power Quality Improvement Using Multicell Dynamic Voltage Restorer

This work is licensed under a Creative Commons Attribution-Share Alike 4.0 International License.Multi-level converter topologies are increasingly being used in various applications due to their high power, high voltage, and low harmonic levels in the output waveforms. These converter topologies produce different output voltage levels and have a highly modular structure. This paper proposes the design of a dynamic voltage restorer (DVR) based on multilevel topology to enhance the voltage profile and improve the power quality in the network. The DVR is an effective, fast-acting device which detects voltage sags and swells in a transmission line and inject a compensating voltage through a boost transformer. A simulation study is carried out under MATLAB/Simulate to demonstrate the performance of the proposed DVR circuit. The simulation results show improved transient response and enhanced power quality in the transmission network.Peer reviewe

New insights into the phytochemical profile and biological properties of Lycium intricatum Bois. (Solanaceae)

This work aimed to boost the valorisation of Lycium intricatum Boiss. L. as a source of high added value bioproducts. For that purpose, leaves and root ethanol extracts and fractions (chloroform, ethyl acetate, n-butanol, and water) were prepared and evaluated for radical scavenging activity (RSA) on 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,20 -azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals, ferric reducing antioxidant power (FRAP), and metal chelating potential against copper and iron ions. Extracts were also appraised for in vitro inhibition of enzymes implicated on the onset of neurological diseases (acetylcholinesterase: AChE and butyrylcholinesterase: BuChE), type-2 diabetes mellitus (T2DM, α-glucosidase), obesity/acne (lipase), and skin hyperpigmentation/food oxidation (tyrosinase). The total content of phenolics (TPC), flavonoids (TFC), and hydrolysable tannins (THTC) was evaluated by colorimetric methods, while the phenolic profile was determined by high-performance liquid chromatography, coupled to a diode-array ultraviolet detector (HPLCUV-DAD). Extracts had significant RSA and FRAP, and moderate copper chelation, but no iron chelating capacity. Samples had a higher activity towards α-glucosidase and tyrosinase, especially those from roots, a low capacity to inhibit AChE, and no activity towards BuChE and lipase. The ethyl acetate fraction of roots had the highest TPC and THTC, whereas the ethyl acetate fraction of leaves had the highest flavonoid levels. Gallic, gentisic, ferulic, and trans-cinnamic acids were identified in both organs. The results suggest that L. intricatum is a promising source of bioactive compounds with food, pharmaceutical, and biomedical applications.info:eu-repo/semantics/publishedVersio

Pyrrolizidine alkaloids from Solenanthus lanatus DC. with acetylcholinesterase inhibitory activity

The whole plant ethanolic extract of Solenanthus lanatus was used for the isolation of acetylcholinesterase inhibitors. A new pyrrolizidine alkaloid, 7-O-angeloylechinatine N-oxide, 1, was isolated together with three known compounds of the same class (3′-O-acetylheliosupine N-oxide, 2, heliosupine N-oxide, 3, and heliosupine, 4), by bioassayguided approach. Their structures were elucidated by spectroscopic methods. All the isolated compounds showed inhibition activity against the AChE, with IC50 0.53–0.60 mM

First study on the pyrrolizidine alkaloids of Pardoglossum cheirifolium (L.) E.Barbier & Mathez.. GC-MS analysis of their volatile components in the whole plant

In this work, the first study on the pyrrolizidine alkaloids content of Pardoglossum cheirifolium (L.) E.Barbier & Mathez. was reported. The studied exemplar was collected in Algeria and the analysis was carried out by means of GC-MS on the crude base extract deriving from the whole plant. Nine compounds were tentatively identified and they all represent new phytochemicals at the species level. Their presence confirms the botanical classification of the plant as a member of the Boraginaceae family. In addition, it points out some interesting chemosystematic relations within the family

Acetylcholinesterase inhibitory activity of pyrrolizidine alkaloids from Echium confusum Coincy

Four pyrrolizidine alkaloids, namely 7-O-angeloyllycopsamine N-oxide 1, echimidine N-oxide 2, echimidine 3 and 7-O-angeloylretronecine 4, were isolated for the first time from the whole plant ethanolic extract of Echium confusum Coincy, through bioassay-guided approach. Their structures were determined by spectroscopic means. All the isolates compounds showed moderate activities in inhibiting AChE, with IC50 0.276–0.769

Phytochemical profiles, antioxidant and antiacetylcholinesterasic activities of the leaf extracts of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire in different solvents

In this work, the extracts obtained with different solvents from the leaves of Rhamnus lycioides subsp. oleoides (L.) Jahand. & Maire were studied for their phytochemical profile and then for their antioxidant and acetylcholinesterase inhibitory activities. The phytochemical profiles of the extracts in n-hexane, dichloromethane, ethyl acetate, methanol, anthraquinone rich and water, showed the presence of different compounds belonging to several classes of natural products such as flavonoids, anthraquinones, saccharides and fatty acids. For what concerns the biological tests, the ethyl acetate, methanol and anthraquinone rich extracts showed the highest activities in both assays due to the high amount of compounds possessing those properties such as flavonoids and anthraquinones. By consequence, these specific extracts of the species may be considered to be potential sources of natural antioxidant and anti-acetylcholinesterasic compounds

Pyrrolizidine alkaloids from Pardoglossum cheirifolium

The ethanolic extract derived from the whole plant of Pardoglossum cheirifolium was submitted to phytochemical investigation. A new pyrrolizidine alkaloid, 3′-O-acetylleptanthine N-oxide (1), was isolated together with three known compounds of the same class, i.e., heliosupine N-oxide (2), heliosupine (3), and heliovicine (4). The structure of the new compound was elucidated after extensive mono- and bidimensional NMR experiments and confirmed by a MS experiment