249 research outputs found

    On the Toxicity of Therapeutically Used Nanoparticles: An Overview

    Get PDF
    Human beings have been exposed to airborne nanosized particles throughout their evolutionary stages, and such exposures have increased dramatically over the last century. The rapidly developing field of nanotechnology will result in new sources of this exposure, through inhalation, ingestion, and injection. Although nanomaterials are currently being widely used in modern technology, there is a serious lack of information concerning the human health and environmental implications of manufactured nanomaterials. Since these are relatively new particles, it is necessary to investigate their toxicological behavior. The objective of this review was to trace the cellular response to nanosized particle exposure. Therapeutic application of selected nanoparticles together with their range of toxic doses was also reviewed. Effect of therapeutically used nanoparticles on cell membrane, mitochondrial function, prooxidant/antioxidant status, enzyme leakage, DNA, and other biochemical endpoints was elucidated. This paper highlights the need for caution during the use and disposal of such manufactured nanomaterials to prevent unintended environmental impacts

    Numerical simulation of GE 7001 EA gas turbine using experimental data for compressor inlet air cooling

    Get PDF
    Paper presented to the 10th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Florida, 14-16 July 2014.In this paper computer Simulation of GE 7001 EA gas turbine that widely used in the kingdom of Saudi Arabia is reported. Simulation is done using cooled air data obtained previously from different experiments. These data are used as input to the compressor to see its effect on the output power and efficiency of the gas turbine. GE 7001EA gas turbine, (GE7121EA models) is simulated using THERMOFLEX software. The specifications of this type of turbines are built in this software. This type of gas turbine model is used in Riyadh and Taif power stations. ISO conditions and actual weather conditions are used for simulations. The results show that the maximum increase in the net power output is about 12, 6 and 5.8% depend on the used cooling data. On the other hand, the maximum percentage increase in efficiency is turned to about 2.5, 1.3 and 0.9 respectively.cf201

    A Sweet Recipe for Consolidated Vulnerabilities: Attacking a Live Website by Harnessing a Killer Combination of Vulnerabilities

    Full text link
    The recent emergence of new vulnerabilities is an epoch-making problem in the complex world of website security. Most of the websites are failing to keep updating to tackle their websites from these new vulnerabilities leaving without realizing the weakness of the websites. As a result, when cyber-criminals scour such vulnerable old version websites, the scanner will represent a set of vulnerabilities. Once found, these vulnerabilities are then exploited to steal data, distribute malicious content, or inject defacement and spam content into the vulnerable websites. Furthermore, a combination of different vulnerabilities is able to cause more damages than anticipation. Therefore, in this paper, we endeavor to find connections among various vulnerabilities such as cross-site scripting, local file inclusion, remote file inclusion, buffer overflow CSRF, etc. To do so, we develop a Finite State Machine (FSM) attacking model, which analyzes a set of vulnerabilities towards the road to finding connections. We demonstrate the efficacy of our model by applying it to the set of vulnerabilities found on two live websites.Comment: Accepted at 5th International Conference on Networking, Systems and Security (5th NSysS 2018

    Malus baccata var. gracilis and Malus toringoides bark polyphenol studies and antioxidant, antimicrobial and anticancer activities

    Get PDF
    Exploring new sources of polyphenols with biological activities that work against human diseases is the target of natural product studies. This study determined the polyphenol composition of the bark of Malus species M. baccata var. gracilis (Rehder) T.C.Ku and M. toringoides (Rehder) Hughes, using high-performance liquid chromatography with a diode-array detector (HPLC-DAD) analysis. The antiproliferative, cytotoxic, antioxidant and antimicrobial applications of these extracts, as well as the identified phenol, were studied. The HPLC-DAD analysis confirmed three polyphenols in the extracts out of the 21 screened compounds: protocatechuic acid, gallic acid, and catechin. The major constituents in M. baccata and M. toringoides were protocatechuic acid, at 3.16 and 7.15 mg 100 g1g^{-1} dry weight (DW), respectively, and catechin, at 5.55 and 6.80 mg 100 g1g^{-1} DW, respectively. M. baccata and M. toringoides bark extracts showed antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), β\beta-carotene bleaching, and ferric-reducing antioxidant power (FRAP) assays, which were attributed to the dominance of protocatechuic acid. The highest antiproliferative and cytotoxic e ects were against Jurkat cells. Against MCF-7 and Hela cells, there was necrotic cell accumulation in the early apoptotic as well as the late apoptotic phase. The bark extracts showed noticeable antibacterial e ects against Listeria monocytogenes, Bacillus cereus, and Escherichia coli. Protocatechuic acid showed comparable results to bark extracts. There were antifungal effects against Aspergillus ochraceus, A. niger, and Candida albicans, and the activities were higher than the commercial reagent. M. baccata and M. toringoides could be considered as a new source of phenolic acids, including protocatechuic acid with anticancer, antibacterial antifungal, and antioxidant-promising effects

    Polyphenol content and biological activities of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia

    Get PDF
    Natural populations of Ruta graveolens L. and Artemisia abrotanum L. in northern Saudi Arabia may be a rich source of natural polyphenols with potential biological activities. Therefore, tentative high-performance liquid chromatography–diode array detection was used to analyze the polyphenol contents of leaf extracts. R. graveolens mainly contained the phenolic acids chlorogenic acid and p-coumaric acid and the flavonoids rutoside and quercetin, whereas those of A. abrotanum mainly contained the phenolic acids isochlorogenic acid and rosmarinic acid and the flavonoid quercetin. Leaf extracts of both species showed antioxidant activities due to the presence of quercetin, chlorogenic acid, and p-coumaric acid as well as antiproliferative and cytotoxic activities against cancer cells, which may be attributed to necrotic cell accumulation during the early and late apoptotic periods. Both species also exhibited antibacterial activity, although the activity was higher in R. graveolens due to the high contents of quercetin and other polyphenols. Finally, both species exhibited antifungal activities, which were associated with specific polyphenols. This is the first study to confirm the richness of polyphenols and wide spectrum of biological activities in natural populations of R. graveolens and A. abrotanum in northern Saudi Arabia

    Saudi Rosmarinus offcinalis and Ocimum basilicum L. polyphenols and biological activities

    Get PDF
    Investigating the polyphenolic profile of natural Rosmarinus offcinalis and Ocimum basilicum populations may reveal essential compounds that have biological activities. Natural populations of R. offcinalis and O. basilicum in Northern Riyadh were investigated by HPLC-DAD analyses. Several polyphenols, including rosmarinic acid, gentisic acid, 3,4-dihydroxyphenylacetic acid, rutoside, and others, out of 38 screened were confirmed. Rosmarinic acid was the major polyphenol in both of R. offcinalis and O. basilicum. R. offcinalis methanolic leaf extracts contained other phenols such as gentisic acid while O. basilicum contained also 3,4-dihydroxyphenylacetic acid and rutoside as well as others. R. o cinalis showed higher antioxidant activities than O. basilicum using 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and β\beta-carotene bleaching assays. These higher activities are associated with a higher composition of rosmarinic acid in leaf extracts. The antioxidant activities of O. basilicum were attributed to identified phenols of rosmarinic acid, 3,4-dihydroxyphenylacetic acid, and rutoside. There were antiproliferative and cytotoxic activities of leaf extracts, as well as identified polyphenols, against several cancer cells. These activities were attributed to the accumulation of necrotic and apoptotic cells in treated cancer cells with leaf extracts as well as identified polyphenols. The antibacterial and antifungal activities of leaf extracts were mainly attributed to 3,4-dihydroxyphenylacetic acid and rutoside in O. basilicum and rosmarinic acid and caffeic acid in R. offcinalis. This study proved that R. offcinalis and O. basilicum natural populations might be considered as promising sources of natural polyphenols with biological activities

    Improving Glass Walls Thermal Resistance In Air-Conditioned Buildings

    Get PDF
    The solar radiation through an air conditioned building depends on what is called the building envelope. Building envelope consists of the surfaces that separate the inside from the building outdoors. Area, direction, and specifications of glass walls; as one of envelope surfaces; has an important impact on solar radiation. Design and construction of glass walls have significant effects on building comfort and energy consumption. This paper describes methods of improving glass walls thermal resistance in air conditioned buildings. Effect of glass wall radiation temperature on the indoor temperature distribution of building rooms is also investigated. Heat gain through various types of glass is discussed. Optimization and testing of these types are carried out theoretically and experimentally as well. A series of experiments on different types of glass with special strips is performed

    Physical interventions to interrupt or reduce the spread of respiratory viruses: systematic review

    Get PDF
    Objective To review systematically the evidence of effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses

    Pharmacology of ORAI channels as a tool to understand their physiological functions

    Get PDF
    Depletion of inositol 1,4,5 trisphosphate-sensitive Ca2+ stores generates a yet unknown signal, which leads to increase in Ca2+ influx in different cell types [J.W. Putney Jr., A model for receptor-regulated calcium entry, Cell Calcium 7 (1986) 1–12]. Here, we describe a mechanism that modulates this store-operated Ca2+ entry (SOC). Ca2+ influx leads to inhibition of protein tyrosine phosphatase 1B (PTP1B) activity in HEK 293 cells [L. Sternfeld, et al., Tyrosine phosphatase PTP1B interacts with TRPV6 in vivo and plays a role in TRPV6-mediated calcium influx in HEK293 cells, Cell Signal 17 (2005) 951–960]. Since Ca2+ does not directly inhibit PTP1B, we assumed an intermediate signal, which links the rise in cytosolic Ca2+ concentration and PTP1B inhibition.We now show that Ca2+ influx is followed by generation of reactive oxygen species (ROS) and that it is reduced in cells preincubated with catalase. Furthermore, Ca2+-dependent inhibition of PTP1B can be abolished in the presence of catalase. H2O2 (100�M) directly added to cells inhibits PTP1B and leads to increase in Ca2+ influx after store depletion. PP1, an inhibitor of the Src family tyrosine kinases, prevents H2O2-induced Ca2+ influx. Our results show that ROS act as fine tuning modulators of Ca2+ entry. We assume that the Ca2+ influx channel or a protein involved in its regulation remains tyrosine phosphorylated as a consequence of PTP1B inhibition by ROS. This leads to maintained Ca2+ influx in the manner of a positive feedback loop
    corecore