252 research outputs found
On the Toxicity of Therapeutically Used Nanoparticles: An Overview
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
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Turbulent convective heat transfer and pressure drop of dilute CuO (copper oxide) - water nanofluid Inside a circular tube
This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Turbulent forced convective heat transfer and pressure drop of 0.01 vol.% CuO-water nanofluid was assessed experimentally. The nanofluids were made flow into a heated horizontal tube under uniform constant heat flux within Reynolds number range of 11,500 to 32,000. The first objective is to know how close traditional correlation/formula for, both, heat transfer and pressure drop can predict nanofluid’s heat transfer and pressure drop. The second is to know how nanofluid’s convective heat transfer and pressure drop are compared to those of its base fluid; in this case water. The results showed that the abovementioned characteristics of the nanofluid can be predicted by the traditional correlation available. It is also found that the nanofluid’s Nusselt number and friction factor, which represent the heat transfer rate and pressure drop, respectively, are close to those of water. Hence, there is no anomaly due to the dispersed nanoparticles within the water.KACST (King Abdulaziz City for Science and Technology
Numerical simulation of GE 7001 EA gas turbine using experimental data for compressor inlet air cooling
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
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
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 dry
weight (DW), respectively, and catechin, at 5.55 and 6.80 mg 100 DW, respectively. M. baccata
and M. toringoides bark extracts showed antioxidant activities using 2,2-diphenyl-1-picrylhydrazyl
(DPPH), -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
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
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 -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
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
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
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
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