Security concerns and economic losses caused by network attacks have inspired extensive network security research with active study fields that include data collection, analysis, and visualization. ...Visualization can help analysts to efficiently detect unusual behavior patterns in a vast amount of data, which should result in a prompt response to a potential security threat. However, the majority of the research papers suggest custom visualization solutions for the proposed analysis techniques rather than using available and well-adopted data pipelines that can further support the analysis. In this paper, we propose a system architecture for clustering, visualization, and computer-assisted network security analysis based on an open-source Elastic Stack. We extended the data pipeline in order to enable data clustering prior to visualization and employed visual mapping techniques to filter data and successfully spot the network assaults. A case study that demonstrates the effectiveness of the proposed solution is given in the example of a port scan attack.
Piece wise affine (PWA) model comprises several affine dynamics defined over polyhedral regions in the regressor (state+input) space. Identification of a PWA model is very often a starting point for ...the controller synthesis of hybrid systems. In this paper we extend the clustering-based procedure for identification of a piece wise autoregressive exogenous (PWARX) model proposed in Ferrari-Trecate et al., 2003. By exploiting a priori process knowledge we choose an appropriate linear transformation of the regression vector for a better and more efficient identification of the process nonlinearities. We significantly reduce the computational complexity of the classification algorithm for finding the complete polyhedral partition of the model domain. This modified clustering-based procedure is used to identify a PWARX model of the electronic throttle-a highly nonlinear component that regulates air inflow to the engine of a car.
The parameters which influence the removal of different zinc (Zn) species: Zn2+, Zn(II)–EDTA and Zn(II)–citrate from aqueous solutions by nanoparticles of zero-valent iron (nZVI) were investigated at ...environmental relevant pH values. Untreated, surface modified and silica-fume supported nZVI were applied at different iron loads and contact times to Zn solutions, which were buffered to pH5.3, 6.0 and 7.0. The results revealed that pH, the type of nZVI, the iron load, the contact time, and the Zn species all had a significant influence on the efficiency of removal. Zn2+, Zn(II)–EDTA and Zn(II)–citrate were the most effectively removed from aqueous solutions by untreated nZVI. Zn2+ removal was governed mainly by adsorption onto precipitated iron oxides. Complete removal of Zn2+ and Zn(II)–citrate was obtained at all pH values investigated. The removal of strong Zn(II)–EDTA complex was successful only at acidic pH, which favored degradation of Zn(II)–EDTA. Consequently, the released Zn2+ was completely removed from the solution by adsorption onto iron oxides.
•Removal of ionic and complexed Zn(II) species from aqueous solutions by nZVI was studied.•Conditions for mutual removal of Zn2+, Zn(II)–EDTA and Zn(II)–citrate were examined.•Untreated, silica-fume supported, and choline dispersed nZVI were used at pH5–7.•Zn2+, Zn(II)–EDTA and Zn(II)–citrate were effectively removed by untreated nZVI.•At pH5 simultaneous removal of ionic and complexed Zn(II) species by nZVI is possible.
Development of nonalcoholic fatty liver disease (NAFLD) occurs through initial steatosis and subsequent oxidative stress. The aim of this study was to examine the effects of α-lipoic acid (LA) on ...methionine–choline deficient (MCD) diet-induced NAFLD in mice. Male C57BL/6 mice (n=21) were divided into three groups (n=7 per group): (1) control fed with standard chow, (2) MCD2 group—fed with MCD diet for 2 weeks, and (3) MCD2+LA group—2 weeks on MCD receiving LA i.p. 100 mg/kg/day. After the treatment, liver samples were taken for pathohistology, oxidative stress parameters, antioxidative enzymes, and liver free fatty acid (FFA) composition. Mild microvesicular hepatic steatosis was found in MCD2 group, while it was reduced to single fat droplets evident in MCD2+LA group. Lipid peroxidation and nitrosative stress were increased by MCD diet, while LA administration induced a decrease in liver malondialdehyde and nitrates+nitrites level. Similary, LA improved liver antioxidative capacity by increasing total superoxide dismutase (tSOD), manganese SOD (MnSOD), and copper/zinc-SOD (Cu/ZnSOD) activity as well as glutathione (GSH) content. Liver FFA profile has shown a significant decrease in saturated acids, arachidonic, and docosahexaenoic acid (DHA), while LA treatment increased their proportions. It can be concluded that LA ameliorates lipid peroxidation and nitrosative stress in MCD diet-induced hepatic steatosis through an increase in SOD activity and GSH level. In addition, LA increases the proportion of palmitic, stearic, arachidonic, and DHA in the fatty liver. An increase in DHA may be a potential mechanism of anti-inflammatory and antioxidant effects of LA in MCD diet-induced NAFLD.
Deficiency in methionine or choline can induce oxidative stress in various organs such as liver, kidney, heart, and brain. This study was to examine the effects of alpha-lipoic acid (LA) on oxidative ...stress induced by methionine and choline deficiency (MCD) in several brain structures. Male mice C57BL/6 (n = 28) were divided into four groups: (1) control – continuously fed with standard chow; (2) LA – fed with standard chow and receiving LA; (3) MCD2 – fed with MCD diet for two weeks, and (4) MCD2+LA – fed with MCD diet for two weeks and receiving LA (100 mg/kg/day intraperitonealy i.p.). Brain tissue (cortex, hypothalamus, striatum and hippocampus) was taken for determination of oxidative stress parameters. MCD diet induced a significant increase in malondialdehyde and NOx concentration in all brain regions, while LA restored their content to normal values. Similar to this, in MCD2 group, activity of total SOD, MnSOD, and Cu/ZnSOD was reduced by MCD diet, while LA treatment improved their activities in all brain structures. Besides, in MCD2 group a decrease in catalase activity in cortex and GSH content in hypothalamus was evident, while LA treatment induced an increase in catalase activity in cortex and striatum and GSH content in hypothalamus. LA treatment can significantly reduce lipid peroxidation and nitrosative stress, caused by MCD diet, in all brain regions by restoring antioxidant enzymes activities, predominantly total SOD, MnSOD, and Cu/ZnSOD, and to a lesser extent by modulating catalase activity and GSH content. LA supplementation may be used in order to prevent brain oxidative injury induced by methionine and choline deficiency.
Aging and ethanol induce oxidative stress due to increased prooxidant production and decreased antioxidative capacity. The aim was to investigate the influence of aging on oxidative stress in liver, ...stomach and pancreas in acute ethanol intoxication. Adult (3 months) and old (18 months) male Wistar rats were divided into the following groups: control (control group rats aged 3 months (C3) and control group rats aged 18 months (C18)) and ethanol-treated groups (ethanol-treated 3-month-old rats (E3) and ethanol-treated 18-month-old rats (E18)). Ethanol was administered in five doses of 2 g/kg at 12-h intervals by orogastric tube. Tissue samples were collected for the determination of oxidative stress parameters. Malondialdehyde (MDA) concentration was increased in all the experimental groups and investigated organs versus C3 group ( p < 0.01). The highest MDA level was observed in the stomach in E18 group when compared with C18 and E3 groups ( p < 0.01). Activity of total superoxide dismutase (SOD) and its isoenzymes (copper-/zinc-SOD and manganese-SOD) in E18 group was significantly decreased when compared with E3 and C18 groups ( p < 0.01). Nitrates and nitrites (NO
x
) concentration was increased in stomach and pancreas for all the groups when compared with C3 group ( p < 0.01). Hepatic, gastric and pancreatic NO
x
level was significantly increased in E18 group when compared with E3 group ( p < 0.01). Moreover, level of NO
x
in liver and pancreas in E18 group was significantly increased when compared with C18 group ( p < 0.01). Aging potentiates ethanol-induced oxidative stress in liver, stomach and pancreas due to increased lipid peroxidation and nitrosative stress and decreased antioxidative tissue capacity.
This paper presents the results of studies on protein polymorphism in seeds of Scots pine (Pinus sylvestris L.) and Austrian pine (Pinus nigra Arn.) as the most important economic species of the ...genus Pinus in Serbia. Polymorphism of protein markers was determined in selected genotypes originating from seven populations (Scots pine) and six populations (Austrian pine). Analysis of protein markers was performed using two statistical methods, NTSYS and correspondence analysis. Both methods give the same arrangement of the analyzed populations, whereby, because of a different view of genetic distances, they can and should be combined, enabling easier and more precise understanding of mutual relationships of the observation units.
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