407 research outputs found

    Ups and Downs of Water Photodecolorization by Nanocomposite Polymer Nanofibers

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    Given the exponentially expanding water pollution causing water scarcity, there is an urgent need for operative nanotechnological systems that can purify water, with insignificant energy consumption, and rapidly. Here, we introduce a nanocomposite system based on TiO 2 nanoparticles (NPs) and PES nanofibers (NFs) that can adsorb and then photodecompose organic water pollutants such as dye molecules. We evaluate pros and cons of this system with respect to its purification efficiency and structural properties that can be impacted by the photocatalytic activity of the nanofillers. While the material is superhydrophilic and able to remove 95% methylene blue (MB) from water via adsorption/photodecomposition, its thermomechanical properties decline upon UV irradiation. However, these properties still remain at the level of the neat NFs. The removal behavior is modeled by the first-and second-order kinetic models from the kinetic point of view. The nanocomposite NFs’ removal behavior complies much better with the second-order kinetic model. Overall, such feedbacks implied that the nanocomposite can be effectively applied for water treatment and the structural properties are still as reliable as those of the neat counterpart.Peer reviewe

    Design, synthesis and antitumor evaluation of novel pyrazolopyrimidines and pyrazoloquinazolines

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    A series of N-aryl-7-aryl-pyrazolo[1,5-a]pyrimidines 18a–u and N-aryl-pyrazolo[1,5-a] quinazolines 25a–c were designed and synthesized via the reaction of 5-aminopyrazoles 11a–c with enaminones 12a–g or 19, respectively. The new compounds were screened for their in vitro antitumor activity toward liver (HepG-2) and breast (MCF-7) human cancer cells using 3-[4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide MTT assay. From the results, it was found that all compounds showed dose-dependent cytotoxic activities against both HepG-2 and MCF-7 cells. Two compounds 18o and 18a were selected for further investigations. Cell cycle analysis of liver (HepG-2) cells treated with 18o and breast (MCF-7) cells treated with 18a showed cell cycle arrest at G2/M phase and pro-apoptotic activity as indicated by annexin V-FITC staining.publishedVersio

    New Algorithm for Drawings of 3-Planar Graphs

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    Graphs arise in a natural way in many applications, together with the need to be drawn. Except for very small instances, drawing a graph by hand becomes a very complex task, which must be performed by automatic tools. The field of graph drawing is concerned with finding algorithms to draw graph in an aesthetically pleasant way, based upon a certain number of aesthetic criteria that define what a good drawing, (synonyms: diagrams, pictures, layouts), of a graph should be. This problem can be found in many such as in the computer networks, data networks, class inter-relationship diagrams in object oriented databases and object oriented programs, visual programming interfaces, database design systems, software engineering…etc. Given a plane graph G, we wish to find a drawing of G in the plane such that the vertices of G are represented as grid points, and the edges are represented as straight-line segments between their endpoints without any edge-intersection. Such drawings are called planar straight-line drawings of G. An additional objective is to minimize the area of the rectangular grid in which G is drawn. In this paper we introduce a new algorithms that finds an embedding of 3-planar graph. Keywords: 3- Planar Graph; Graph Drawing; drawing on grid

    Amenability of heap leaching technology on uranium extraction from Gattar and El Missikat area, Eastern Desert, Egypt: A kinetic approach

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    Studies of uranium heap leaching from different uranium mineralization situated in Eastern Desert of Egypt was investigated via batch experiments, followed by its optimum condition applicationon column percolationtests.The optimum process operating parameters were implemented on large column scale in order to make more condition control and evaluate the time and reagents needed in the large scale. The results show thatleaching efficiency of GIIattained about 78.3% with 34kg/ton acid consumption in a 44 days period, while leaching efficiency of El-Missikat attained about 86.6% with 28kg/ton acid consumption in a 40 days period.Kinetics reaction models of column tests have been investigated to optimize the column leaching behavior. Based on the leaching results of two mineralized samples, the rate of the uranium metal dissolution is controlled by the chemical reaction and the diffusion reaction but diffusion reaction control was more predominate than a chemical reaction control

    The effect of green competencies and values on carbon footprint on sustainable performance in healthcare sector

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    This research investigates how green competencies and values associated with carbon footprint directly influence sustainable performance. Additionally, it seeks to assess the indirect influence of green competencies and values concerning carbon footprint on sustainable performance, mediated by the willingness to mitigate carbon emissions. The research model was analyzed using Structural Equation Modeling (SEM), and data from 269 healthcare organizations were employed for this purpose. The findings reveal several significant relationships. Firstly, Green competencies were observed to positively and significantly influence the willingness to mitigate carbon footprint. Secondly, values related to carbon footprint were also found to positively influence the willingness to mitigate carbon footprint. Furthermore, the willingness to mitigate carbon footprint was identified as a positive enhancer of sustainable performance within healthcare organizations. In terms of indirect relationships and the mediation effect of willingness to mitigate carbon footprint, the results indicate that this willingness acts as a mediator. It mediates the connection between green competencies and sustainable performance, as well as between values related to carbon footprint and sustainable performance. As a result, this study contributes theoretically to four distinct areas. Additionally, it offers practical insights for healthcare managers and policymakers. Lastly, the study suggests possible directions for future research endeavours

    Stimuli-responsive hydrogels: smart state of-the-art platforms for cardiac tissue engineering

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    Biomedicine and tissue regeneration have made significant advancements recently, positively affecting the whole healthcare spectrum. This opened the way for them to develop their applications for revitalizing damaged tissues. Thus, their functionality will be restored. Cardiac tissue engineering (CTE) using curative procedures that combine biomolecules, biomimetic scaffolds, and cells plays a critical part in this path. Stimuli-responsive hydrogels (SRHs) are excellent three-dimensional (3D) biomaterials for tissue engineering (TE) and various biomedical applications. They can mimic the intrinsic tissues’ physicochemical, mechanical, and biological characteristics in a variety of ways. They also provide for 3D setup, adequate aqueous conditions, and the mechanical consistency required for cell development. Furthermore, they function as competent delivery platforms for various biomolecules. Many natural and synthetic polymers were used to fabricate these intelligent platforms with innovative enhanced features and specialized capabilities that are appropriate for CTE applications. In the present review, different strategies employed for CTE were outlined. The light was shed on the limitations of the use of conventional hydrogels in CTE. Moreover, diverse types of SRHs, their characteristics, assembly and exploitation for CTE were discussed. To summarize, recent development in the construction of SRHs increases their potential to operate as intelligent, sophisticated systems in the reconstruction of degenerated cardiac tissues

    Perioperative opioids and survival outcomes in resectable head and neck cancer: A systematic review.

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    BACKGROUND: Opioids are a mainstay in pain control for oncologic surgery. The objective of this systematic review is to evaluate the associations of perioperative opioid use with overall survival (OS) and disease-free survival (DFS) in patients with resectable head and neck cancer (HNC). METHODS: A systematic review of PubMed, SCOPUS, and CINAHL between 2000 and 2022 was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies investigating perioperative opioid use for patients with HNC undergoing surgical resection and its association with OS and DFS were included. RESULTS: Three thousand three hundred seventy-eight studies met initial inclusion criteria, and three studies representing 562 patients (intraoperative opioids, n = 463; postoperative opioids, n = 99) met final exclusion criteria. One study identified that high intraoperative opioid requirement in oral cancer surgery was associated with decreased OS (HR = 1.77, 95% CI 0.995-3.149) but was not an independent predictor of decreased DFS. Another study found that increased intraoperative opioid requirements in treating laryngeal cancer was demonstrated to have a weak but statistically significant inverse relationship with DFS (HR = 1.001, p = 0.02) and OS (HR = 1.001, p = 0.02). The last study identified that patients with chronic opioid after resection of oral cavity cancer had decreased DFS (HR = 2.7, 95% CI 1.1-6.6) compared to those who were not chronically using opioids postoperatively. CONCLUSION: An association may exist between perioperative opioid use and OS and DFS in patients with resectable HNC. Additional investigation is required to further delineate this relationship and promote appropriate stewardship of opioid use with adjunctive nonopioid analgesic regimens
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