50 research outputs found

    Evaluation of sesamum gum as an excipient in matrix tablets

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    In developing countries modern medicines are often beyond the affordability of the majority of the population. This is due to the reliance on expensive imported raw materials despite the abundance of natural resources which could provide an equivalent or even an improved function. The aim of this study was to investigate the potential of sesamum gum (SG) extracted from the leaves of Sesamum radiatum (readily cultivated in sub-Saharan Africa) as a matrix former. Directly compressed matrix tablets were prepared from the extract and compared with similar matrices of HPMC (K4M) using theophylline as a model water soluble drug. The compaction, swelling, erosion and drug release from the matrices were studied in deionized water, 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) using USP apparatus II. The data from the swelling, erosion and drug release studies were also fitted into the respective mathematical models. Results showed that the matrices underwent a combination of swelling and erosion, with the swelling action being controlled by the rate of hydration in the medium. SG also controlled the release of theophylline similar to the HPMC and therefore may have use as an alternative excipient in regions where Sesamum radiatum can be easily cultivated

    Mobile app stores from the user's perspectives

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    YesThe use of smartphones has become more prevalent in light of the boom in Internet services and Web 2.0 applications. Mobile stores (e.g., Apple’s App Store and Google Play) have been increasingly used by mobile users worldwide to download or purchase different kinds of applications. This has prompted mobile app practitioners to reconsider their mobile app stores in terms of design, features and functions in order to maintain their customers’ loyalty. Due to the lack of research on this context, this study aims to identify factors that may affect users’ satisfaction and continued intention toward using mobile stores. The proposed model includes various factors derived from information systems literature (i.e., usefulness, ease of use, perceived cost, privacy and security concerns) in addition to the dimensions of mobile interactivity (i.e. active control, mobility, and responsiveness). The study sets out 13 hypotheses that include mediating relationships (e.g., perceived usefulness mediates the influence of ease of use, active control, responsiveness and mobility; perceived ease of use mediates the influence of active control). As well as outlining the proposed research method, the research contributions, limitations and future research recommendations are also addressed

    Compressed-Domain Detection and Estimation for Colocated MIMO Radar

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    This article proposes a compressed-domain signal processing (CSP) multiple-input multiple-output (MIMO) radar, a MIMO radar approach that achieves substantial sample complexity reduction by exploiting the idea of CSP. CSP MIMO radar involves two levels of data compression followed by target detection at the compressed domain. First, compressive sensing is applied at the receive antennas, followed by a Capon beamformer, which is designed to suppress clutter. Exploiting the sparse nature of the beamformer output, a second compression is applied to the filtered data. Target detection is subsequently conducted by formulating and solving a hypothesis testing problem at each grid point of the discretized angle space. The proposed approach enables an eightfold reduction of the sample complexity in some settings as compared to a conventional compressed sensing (CS) MIMO radar, thus enabling faster target detection. Receiver operating characteristic curves of the proposed detector are provided. Simulation results show that the proposed approach outperforms recovery-based CS algorithms. </p

    Compressed-Domain Detection and Estimation for Colocated MIMO Radar

    No full text
    This article proposes a compressed-domain signal processing (CSP) multiple-input multiple-output (MIMO) radar, a MIMO radar approach that achieves substantial sample complexity reduction by exploiting the idea of CSP. CSP MIMO radar involves two levels of data compression followed by target detection at the compressed domain. First, compressive sensing is applied at the receive antennas, followed by a Capon beamformer, which is designed to suppress clutter. Exploiting the sparse nature of the beamformer output, a second compression is applied to the filtered data. Target detection is subsequently conducted by formulating and solving a hypothesis testing problem at each grid point of the discretized angle space. The proposed approach enables an eightfold reduction of the sample complexity in some settings as compared to a conventional compressed sensing (CS) MIMO radar, thus enabling faster target detection. Receiver operating characteristic curves of the proposed detector are provided. Simulation results show that the proposed approach outperforms recovery-based CS algorithms. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Circuits and System

    TiO2/g-C3N4/SO3H(IL) : unique usage of ionic liquid-based sulfonic acid as an efficient photocatalyst for visible-light-driven preparation of 5-HMF from cellulose and glucose

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    Upgrading of biomass wastes to value-added materials has been incessantly pursued worldwide with diverse applications, especially deploying photocatalytic composites encompassing metal oxides with acidic and carbon compounds. Herein, the fabrication of a morphologically unique acidic catalyst encompassing a two-dimensional (2D) TiO2/g-C3N4 heterojunction feature is described for the generation of 5-hydroxymethylfurfural (5-HMF), which exploits the acidic/ionic liquid (IL) bifunctional photocatalysis under visible light. The structural integrity of the synthesized TiO2/g-C3N4/SO3H(IL) was corroborated by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy-energy-dispersive spectroscopy (EDX-EDS), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), field emission scanning electron microscopy (FESEM), UV-vis, Tauc plots, transmission electron microscopy (TEM), and Brunauer-Emmett-Teller-Barrett-Joyner-Halenda (BET-BJH) analyses. Keeping environmental impact in mind, there are compelling advantages in the development of bio-derived pathways to access ILs from natural renewable resources. The outcomes of environmental assessments have revealed that the incorporation of TiO2 in g-C3N4 and ClSO3H can reduce the probability of recombination due to ionic charges present, therefore enhancing the photocatalytic activity via the transformation of cellulose and glucose to produce 5-HMF in higher yields, with the optimum conditions being reaction in water under a blue light-emitting diode (LED), at 100 °C, for 1-1.5 h. The main advantages of this production method include minimum number of synthetic steps as well as ample availability of and easy access to primary ingredients. While a significant volume of 5-HMF was produced under blue light-emitting diode (LED) radiation, the selectivity was drastically reduced in the dark. The salient attributes of the catalyst comprise stability in air, robustness, reusability, and its overall superior activity that is devoid of hazardous additives or agents. This inimitable method has uncovered a newer strategy for enhancing the photocatalytic attributes of deployed semiconducting materials for numerous photocatalytic functions while adhering to the tenets of environmental friendliness
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