Flavonoids have been documented to have good antioxidant activities in vitro. In recent years, reports on the antioxidant activities of flavone C-glycosides, a subclass of flavonoids, have attracted great attention. Despite the wealth of information on this subject, the correlation between structure and function is not well understood. In this work, the relationship between the structure and the antioxidant activity of 12 flavone C-glycosides extracted from the aerial part of winter linseed (Linum usitatissimum L.) was studied to fill the current gaps. Orientin, isoorientin, vitexin, isovitexin, swertisin, swertiajaponin, carlinoside, schaftoside, lucenin-1, lucenin-2, vicenin-1, and vicenin-2 were purified by preparative HPLC and by the drowning-out crystallization method. Then, the control of the purity and the confirmation of the chemical structures were assessed by LC-MS and NMR analyses. The antioxidant activity was evaluated using ABTS, CUPRAC, FRAP, and iron chelating activity in vitro assays. Luteolin and its flavone C-glycoside derivatives exhibited higher antioxidant activity than apigenin and its flavone C-glycosides derivatives. This could be attributed to the ortho-dihydroxyl groups at C-3′ and C-4′ of the B ring in the flavonoid skeleton, which seemed to play an important role in antioxidant behavior. These results indicate that the antioxidant activity of these compounds, derived from apigenin and luteolin, can be closely related to their structural characteristics, including the position and nature of the sugars, the number of hydroxyl groups, and the presence of methyl group.
Basically, augmented reality (AR) technology grants innovative ways so as to manipulate and visualize a three-dimensional (3D) model of an object through superimposing computer-generated images onto another object interactively. Being able to interact in real-time with digital and spatial information offers further chances in order to manipulate medical data efficiently and easily. In fact, surgeons encounter multiple challenges handling digital patient data during surgical interventions. Multiple techniques are invested in order to visualize the operative areas, as for example fluoroscopy and ultrasound methods. The latter display certain deficiencies. Therefore, the AR technique can stand for a good candidate in order to project a 3D model of a target organ into the surgeon's perspective and view field so as to enhance the efficiency and accuracy of the medical intervention intraoperatively. The basic target of this paper is to simulate a generated biomechanical model of the liver organ and visualize its deformations through the use of an AR headset during the open surgery. The proposed approach is validated by the use of acquired CT scans of a human liver organ.
This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/policies/article-withdrawal).This abstract has been retracted at the request of the author H. Allaoui and her supervisor E. Messadi, because of the latter's lack of consent to publish the text which still contained errors.
The Tunisian musical system is not yet well defined rigorously in terms of its musical scale compared to other modal systems, such as the Turkish and Persian system and now included in the Arab musical system. Given that these last two have known studies which attempt to find theoretical formulas which almost translate the magnitudes of the intervals by semantic signs which correspond to their melodic specificities. Our following study is considered a musicometric specimen to elicit researchers to reveal the nature of Tunisian tbus (modes). We first approached the theoretical Arab models which refuted the quarter-tone system reported by the modes and rhythms committee of the Arab Music Congress in Cairo in 1932. We have proved, moreover, that through two analyzed examples of the tbâ (mode) dhil, there is no similarity in the quantities of the melodic intervals, in particular the modal notes (sikah « mi half flat», awj « si2 half flat », araq « si1 half flat ») that we were satisfied with in our objective, which evokes the dispute over the referential musical scale of this tbâ and its scalar system.We have mentioned that the musical scale depends on the musician and his interpretation, these cultural tendencies or his usual auditory memory which has influenced his tastes and the musical culture which belongs to him, as well as by the impact of certain factors interpretation. We are ultimately looking to find a very rigorous theoretical model for this tbâ and for the other Tunisian tubu by introducing artificial intelligence and expanding the number of recordings analyzed which can give us satisfactory results.
