INVESTIGATING THE IMPACT OF TREE-BASED NETWORK TOPOLOGY ON THE SDN CONTROLLER PERFORMANCE

Software Defined Networking (SDN) is an important technology that enables a new approach to how we develop and manage networks. SDN divides the data plane and control plane and promotes logical centralization of network control so that the controller can schedule the data in the network effectively through the OpenFlow protocol. The performance and capabilities of the controller itself are important. The impact of network topology type on controller performance can be very significant. In order to have better communication in SDN, it is essential to have an analysis of the performance of specific network topologies. In this paper, we simulate ONOS and RYU controllers and compare their different network parameters under the proposed complex custom Tree-based topology. A network topology has been designed using a Mininet emulator, and the code for topology is executed in Python. From the throughput, packet transmission rate, and latency analysis, the ONOS controller displayed better results than RYU, showing that it can respond to requests more efficiently under complex SDN topologies and traffic loads. On the contrary, the RYU controller provides better results for the less complex SDN networks

SUMMARY

Background: Samples of blood, kidney, and liver per animal were randomly selected from slaughtered pigs (n=60) and analyzed for ochratoxin A. Methods: Determination of ochratoxin A concentration in samples of kidney and liver was performed by high-performance thinlayer chromatography after immunoaffnity column clean up, while for plasma samples, a spectrofluorometric procedure was used. Results: Of the 60 plasma samples, 60 % contained ochratoxin A in the range of 2.5-33.3 ng/mL (mean 3.05±5.0 ng/mL), while the incidence of ochratoxin A in kidneys and liver were very similar (70 % and 65%). The average ochratoxin A concentration in liver was 3.2±4.35 ng/g (1.2-19.5 ng/g) and in kidneys was 3.97±4.47 ng/g (1.3-22.0 ng/g). A statistically significant difference (p<0.01) was found between region Bačka Topola and Kovilj for both liver and kidney samples. In kidney samples originating from region Kovilj and Senta, a statistically significant difference (p<0.01) was found. Mean distribution followed the pattern: kidney>liver>serum (100>80.8>77%). The results from this survey indicated that there was a strong correlation between the ochratoxin A level in serum and liver as well as in the ochratoxin A serum in kidney (r=0.884 and r=0.896, respectively) while the strongest correlation was found between the ochratoxin A level in liver and in kidney (r=0.970). Conclusion: The results of present study show that pork tissues as well as pork products are considered an important source of ochratoxin A in humans

Residue of ochratoxin A in swine tissues: Risk assessment

Background: Samples of blood, kidney, and liver per animal were randomly selected from slaughtered pigs (n=60) and analyzed for ochratoxin A. Methods: Determination of ochratoxin A concentration in samples of kidney and liver was performed by high-performance thinlayer chromatography after immunoaffnity column clean up, while for plasma samples, a spectrofluorometric procedure was used. Results: Of the 60 plasma samples, 60% contained ochratoxin A in the range of 2.5-33.3 ng/mL (mean 3.05±5.0 ng/mL), while the incidence of ochratoxin A in kidneys and liver were very similar (70% and 65%). The average ochratoxin A concentration in liver was 3.2±4.35 ng/g (1.2-19.5 ng/g) and in kidneys was 3.97±4.47 ng/g (1.3-22.0 ng/g). A statistically significant difference (p<0.01) was found between region Bačka Topola and Kovilj for both liver and kidney samples. In kidney samples originating from region Kovilj and Senta, a statistically significant difference (p<0.01) was found. Mean distribution followed the pattern: kidney>liver>serum (100>80.8>77%). The results from this survey indicated that there was a strong correlation between the ochratoxin A level in serum and liver as well as in the ochratoxin A serum in kidney (r=0.884 and r=0.896, respectively) while the strongest correlation was found between the ochratoxin A level in liver and in kidney (r=0.970). Conclusion: The results of present study show that pork tissues as well as pork products are considered an important source of ochratoxin A in humans

Izolacija i molekularna detekcija parainfluenca 3 virusa kod goveda u Srbiji

The presence of bovine parainfluenza virus type 3 (BPIV3) was examined in 119 nasal swabs collected from cattle with severe respiratory infection. All samples were conducted for virus isolation on the MDBK cell line. The cytopathic effect was observed after 48h to 72h in cells inoculated with eight samples (8/119; 6.7%). The confirmation of isolated strains of BPIV3 was done by the virus-neutralization test. In addition, all samples of bovine nasal swabs were also examined for the presence of BPIV3 virus using RT-PCR with primers specific for the part of HN gene. The presence of BPIV3 was detected in eight samples (8/119; 6.7%) that were also positive upon virus isolation. The molecular characterization based on nucleotide sequencing of the part of the HN gene showed that all BPIV3 isolates belonged to genotype C of BPIV3. They branched in one distinct cluster with three different branches, but these branches were very similar to each other (98.1% to 99.8%). Serbian BPIV3c isolates were most similar to the Chinese BPIV3c isolates SD0805, SD0809 and SD0835 (from 97.92% to 99.7%), and to South Korean (12Q061), Japanese (HS9) and American (TVMDL16 and TVMDL20) BPIV3c strains (from 97.1% to 98.8%), and distinct from American (TVMDL15and TVMDL17) and Australian (Q5592) BPI3V genotype B strains (only 79.9% to 82.3% similarity), as well as from the genotype A BPIV3 strains from different countries published in GenBank.Ukupno je ispitano 119 uzoraka nosnih briseva goveda na prisustvo parainfluenca 3 virusa goveda (bovine parainfluenza virus type, eng. - 3 BPIV3). Iz svih uzoraka nosnih briseva je vršena izolacija virusa na ćelijskoj liniji MDBK. Pojava citopatogenog efekta na kulturi ćelija, nakon 48h, odnosno 72h, utvrđena je kod osam uzoraka nosnih briseva (8/119; 6.7%). Identifikacija izolovanih sojeva BPIV3 je izvršena primenom virus neutralizacionog testa. Dodatno, svi uzorci nosnih briseva goveda su ispitani na prisustvo BPIV3 i primenom metode RT-PCR uz korišćenje prajmera specifičnih za deo HN gena virusa. Prisustvo virusne nukleinske kiseline je utvrđeno kod osam uzoraka nosnih briseva (8/119; 6.7%), koji su bili pozitivni i na izolaciji virusa. Molekularna karakterizacija zasnovana na sekvenciranju dela HN gena izolata BPIV3 iz Srbije je potvrdila da svi pripadaju genotipu C BPIV3 (BPIV3c). Oni su se u filogenetskom stablu granali u tri različite grane koje su međusobno veoma slične (98.1% do 99.8%). Izolati BPIV3 iz Srbije su pokazali visok stepen sličnosti nukleotidnih sekvenci sa BPIV3c sojevima SD0805, SD0809 i SD0835 iz Kine (97.92% do 99.7%), odnosno sa BPIV3c sojevima 12Q061 iz Južne Koreje, HS9 iz Japana i TVMDL16 i TVMDL20 iz Amerike (sličnost od 97.1% do 98.8%), kao i različitosti u odnosu na nukleotidne sekvence sojeva TVMDL15 i TVMDL17 izolovanih u Americi i soja Q5592 izolovanog u Australiji, a koji su pripadali genotipu B BPIV3 (sličnost od 79.9% do 82.3%). Slična razlika je utvrđena i sa nukleotidnim sekvencama sojeva virusa, poreklom iz različitih država, svrstanih u genotip A BPIV3, a objavljenih u genskoj bazi podataka (NCBI GenBank)