139 research outputs found
Derivatives combining the fragment of pyrazinamide and 4-aminosalicylic acid as antimycobacterial compounds
No full textCharles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical chemistry and Pharmaceutical analysis Author: Petr Šlechta Supervisor: doc. PharmDr. Jan Zitko, Ph.D. Consultant: MSc. Ghada Basem Bouz, Ph.D. Title of diploma thesis: Derivatives combining the fragment of pyrazinamide and 4-aminosalicylic acid as antimycobacterial compounds According to WHO, tuberculosis (TB) is the leading cause of death from a single infectious organism worldwide and the number of cases with drug resistant TB is still increasing, creating the need for new antituberculotics. Therefore, we report design, synthesis and antimicrobial evaluation of a series of hybrid compounds combining different pyrazinamide derivates and p- aminosalicylic acid as potential antituberculotic agents. The compounds were prepared by mixing different pyrazinecarboxylic acids, after activation by 1,1'-carbonyldiimidazole, with p- aminosalicylic acid in dimethylsulfoxide as a solvent. Obtained compounds were in vitro tested for their antimycobacterial activity against M. tuberculosis H37Rv, M. tuberculosis H37Ra and four other mycobacterial strains. Prepared compounds were also in vitro screened for antibacterial, antifungal, and cytotoxic (HepG2) activity. Most compounds showed antimycobacterial activity in range of..
The Arab Intellectual as a Woman: The Writings of Ghada Samman
No full textGhada Samman (b. 1942) is a prominent literary figure with an established legacy across the Arabic-speaking world. Through her widely-acclaimed writings, the Syrian author, journalist, and critic occupies a unique position in Arab intellectual circles as a woman who combines a commitment to the peoples’ causes with an innovative literary style vividly capturing the estrangement faced by the modern Arab subject. Samman has spent her life in exile, first in Beirut and eventually settling in Paris when the Lebanese Civil War (1975-1990) escalated. She has published 10 poetry books, 6 short story collections, 5 novels, and 20 collections of essays. However, despite her influential writings, Samman is relatively unknown outside of the Arabic-speaking world and a negligible portion of her corpus has been translated into English. My presentation posits the reason for this exclusion being that the Anglophone world does not know where to place Samman as she refuses the mould of “women’s writing” to which the Western academy is accustomed. Hers is the broad, interdisciplinary concern of the intellectual, writing on themes of exile, diatribes against capitalism and classism, the liberation of sexuality from prescribed norms, as well as how patriarchal hegemonies victimise both men and women. Even in the Arabic-speaking world she has pushed back against reductive labelling of her work, writing in a 1987 article: ‘My allegiance is to my freedom and my faith in a woman’s ability to write great human literature. There’s no need to call it “feminist” when its defence of women is part and parcel of its defence of all who are oppressed in Arab societies.’ My presentation will explore the life and work of Ghada Samman from the position of an Arab intellectual rather than a limited (and expected) reading of her as a woman writer exclusively concerned with “women’s issues”
Characterization and Structural Elucidation of the Complex Mixture Thearubigins in Black Tea using Advanced Analytical Mass Spectrometry
No full textThearubigins are the most abundant pigments found in black tea, contributing to a wide range of heterogeneous fractions of polyphenolic oxidation products. The term thearubigins has been introduced fifty years ago but up till now their chemical nature remained unresolved and a challenge for the scientists despite many attempts and efforts made to understand their composition. Detailed structural knowledge of thearubigins is of high interest to understand their sensory properties in order to assist the manufacturing and quality of black tea as an economically important beverage. By employing a strategy in combining a series of advanced powerful mass spectrometry techniques, the chemical composition and structural elucidation of these compounds were achieved. A series of analytical mass spectrometry experiments including ESI-LC tandem mass and ESI-LC-TOF mass spectrometry, MALDI-TOF-TOF mass spectrometry, ESI-UPLC ion mobility mass spectrometry, MALDI imaging mass spectrometry were employed in combination with experimental potentiostatic studies and theoretical computational analysis. In this work, two classes of compounds were identified and a new structural hypothesis in thearubigin formation was further substantiated. The data revealed the presence of polyhydroxylated dimers of the theanaphthaquinone and theasinensin C structures, which were consistent with the polyhydroxylation hypothesis previously formulated. Furthermore, new class of peroxo-/ epoxi- compounds in the series of theasinensin A were identified, thus indicating the presence of H2O2 and its important contribution in the tea fermentation process. A series of novel trimeric and tetrameric catechins were identified. The results showed that the structures of these compounds provide for the first time experimental evidence on oxidative oligomerisation of flavan-3-ols through an oxidative coupling pathway, most notably between theaflavin/ theasinensin and oxidized flavan-3-ols. Furthermore, the regiochemistry of the new trimeric structures were suggested based on computational studies. Isomeric structures were also resolved based on the energy dimension in direct infusion MSn experiments.
An electrochemical model oxidation system was established. Theasinensins, theaflavins and their gallate esters were identified and shown as the main reaction products obtained from the electrochemical oxidation process performed, thus acting as the main precursors for further oxidation processes in thearubigin formation. Since thearubigins are one of the most complex mixtures present in nature, being composed of sets of multiple isomers, the differentiation between isomeric structure of theasinensins, proanthocyanidins B-type, and rutin (Quercetin-3-O-rutinoside) were studied according to their mobility drift times acquired and the assignment of the individual isomeric structures were based on comparison between their experimental drift times and theoretical collisional cross sections. Furthermore, polyphenolic components present in the tea leaves and their spatial distribution were located allowing a molecular mapping of the green tea constituents to be achieved. A new free matrix MS imaging method was developed for the first time, where the biochemical process occurring in a young green tea leaf has been determined. Finally, the importance of thearubigins on the health benefits by studying its inhibitory activity on nutrient cultures containing both gram positive and gram negative bacteria was highlighted.
This study characterizes the thearubigin as a complex mixture, reveals the important reaction mechanism occurring and identifies novel components, shows the main polyphenolic occurring components as main precursors in the oxidation process, demonstrates the isomerism present in thearubigin fractions, reveals the initial biochemical processing in the leaf matrix, and shows its important biological activity. In a word, this study serves a step forward for unraveling the mystery of black tea
Modeling and Simulation of Highly Efficient and Eco-Friendly Perovskite Solar Cells Enabled by 2D Photonic Structuring and HTL-Free Design
No full textA novel, eco-friendly perovskite solar cell design is investigated using numerical simulations based on the finite-difference time-domain (FDTD) method. The proposed structure incorporates a two-dimensional (2D) photonic crystal (PhC) architecture featuring a titanium dioxide (TiO2) cylindrical electron extraction layer. To reduce fabrication complexity and overall production costs, a hole-transport-layer-free (HTL-free) configuration is employed. Simulation results reveal a significant enhancement in photovoltaic performance compared to conventional planar structures, achieving an ultimate efficiency of 42.3%, compared to 36.6% for the traditional design—an improvement of over 16%. Electromagnetic field distributions are analyzed to elucidate the physical mechanisms behind the enhanced absorption. The improved optical performance is attributed to strong coupling between photonic modes and surface plasmon polaritons (SPPs), which enhances light–matter interaction. Furthermore, the device exhibits polarization-insensitive and angle-independent absorption characteristics, maintaining high performance for both transverse magnetic (TM) and transverse electric (TE) polarizations at incidence angles up to 60°. These findings highlight a promising pathway toward the development of cost-effective, lead-free perovskite solar cells with high efficiency and simplified fabrication processes
Ladder Bottom-up Convolutional Bidirectional Variational Autoencoder for Image Translation of Dotted Arabic Expiration Dates
No full textThis paper proposes an approach of Ladder Bottom-up Convolutional Bidirectional Variational Autoencoder (LCBVAE) architecture for the encoder and decoder, which is trained on the image translation of the dotted Arabic expiration dates by reconstructing the Arabic dotted expiration dates into filled-in expiration dates. We employed a customized and adapted version of Convolutional Recurrent Neural Network CRNN model to meet our specific requirements and enhance its performance in our context, and then trained the custom CRNN model with the filled-in images from the year of 2019 to 2027 to extract the expiration dates and assess the model performance of LCBVAE on the expiration date recognition. The pipeline of (LCBVAE+CRNN) can be then integrated into an automated sorting systems for extracting the expiry dates and sorting the products accordingly during the manufacture stage. Additionally, it can overcome the manual entry of expiration dates that can be time-consuming and inefficient at the merchants. Due to the lack of the availability of the dotted Arabic expiration date images, we created an Arabic dot-matrix True Type Font (TTF) for the generation of the synthetic images. We trained the model with unrealistic synthetic dates of 60,000 images and performed the testing on a realistic synthetic date of 3000 images from the year of 2019 to 2027, represented as yyyy/mm/dd. In our study, we demonstrated the significance of latent bottleneck layer with improving the generalization when the size is increased up to 1024 in downstream transfer learning tasks as for image translation. The proposed approach achieved an accuracy of 97% on the image translation with using the LCBVAE architecture that can be generalized for any downstream learning tasks as for image translation and reconstruction.* Corresponding author E-mail address: ghadasoliman@orangecom Received: 14 April 2024; Accepted: 28 August 2024; Published: 30 September 202
Ġāda as-Sammān fī riḥlātihā aw kayfa yuṣbiḥu al-ǧasad ḥaqībat safar
No full textIn a book entitled "The Body is a Suitcase" Ghada as-Samman publishes narratives from places visited by her in the years 1964-1976. In the form of essays and reportages she describes European and Arab cities, including many capitals. These materials that resulted finally in the abovementioned 520-page book had been earlier published separately in two Lebanese journals and one of them also in a Kuwaiti journal. In her works as-Samman do not focuses on descriptions of visited places but she shows noteworthy and often surprising phenomena or cases that should be interesting for the curious Arab reader. She picks untypical traditions and titbits referring to the daily life of the European societies and correlates them with Arabian traditions. The aim of this paper is to analyse the concept of journey in terms of Ghada as-Samman works and destabilisation as a consequence of the journey. Ghada as-Samman herself declares that destabilisation instigates the people to think. Therefore, during her journey she contemplates many important issues relevant to the cultural and political life of Arabs. Language used by the author is very colourful so in this paper it also forms an area of investigation. It is worth noticing that sometimes as-Samman’s works are full of metaphors and beautiful expressions adeptly and tastefully used by the author. On the other hand, some of her essays are written in simple language and can be understood directly – the conclusion is that Ghada Samman’s main goal was to make her works get to the broadest audience possible
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Middle Eastern Studies Newsletter 2010-2011, No. 34
No full textNew Ancient Israel and the Near East program; interview with Ghada Abdel Aal, author of I Want to Get Married! The Jil Jadid graduate student conference in Arabic literature and linguistics; a visit by Adonis; Arabic House co-op; Intensive Persian language summer institute; teacher study abroad; outreach lecture series; the new push for Turkish studies.Middle Eastern Studie
Remote sensing-based automatic detection of shoreline position: A case study in apulia region
No full textRemote sensing and satellite imagery have become commonplace in efforts to monitor and model various biological and physical characteristics of the Earth. The land/water interface is a continually evolving landscape of high scientific and societal interest, making the mapping and monitoring thereof particularly important. This paper aims at describing a new automated method of shoreline position detection through the utilization of Synthetic Aperture Radar (SAR) images derived from European Space Agency satellites, specifically the operational SENTINEL Series. The resultant delineated shorelines are validated against those derived from video monitoring systems and in situ monitoring; a mean distance of 1 and a maximum of 3.5 pixels is found.</p
Palestine in London: Palestinian and Jewish Lifeworlds after the Foundation of the State of Israel
No full textThe article is based on Ghada Karmi’s autobiography published in 2002 and deals with the problem of forced migration and the establishment of a new life and a new identity in London. Expelled with her family from Jerusalem in 1948, Ghada describes her desire and attempts to become integrated in British society. Confronted with racism directed at the new wave of immigrants in the 1960’s, her newly-developed British identity was questioned from outside while her Palestinian identity was weakened and the Arab culture conveyed by her parents had no real meaning for her generation. The author argues that it was precisely this problem of living in a Zwischenwelt (intermediate world) that made Ghada’s generation receptive to political ideologies imported from the Middle East, such as the Panarabism of Nasser or a secular Palestinian identity symbolised by Arafat.The article is based on Ghada Karmi’s autobiography published in 2002 and deals with the problem of forced migration and the establishment of a new life and a new identity in London. Expelled with her family from Jerusalem in 1948, Ghada describes her desire and attempts to become integrated in British society. Confronted with racism directed at the new wave of immigrants in the 1960’s, her newly-developed British identity was questioned from outside while her Palestinian identity was weakened and the Arab culture conveyed by her parents had no real meaning for her generation. The author argues that it was precisely this problem of living in a Zwischenwelt (intermediate world) that made Ghada’s generation receptive to political ideologies imported from the Middle East, such as the Panarabism of Nasser or a secular Palestinian identity symbolised by Arafat
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