Prisustvo sojeva stafilokoka rezistentnih na meticilin kod studenata Fakulteta veterinarske medicine Univerziteta u Beogradu

Resistance to methicillin in staphylococci is considered to be one of the most dangerous forms of bacterial resistances to antibiotics. Methicillinresistant staphylococci (MRS) are zoonotic agents which cause local and systemic infections in humans and animals, often with a fatal outcome due to the absence of adequate antibiotic therapy. People colonized with strains of MRS are asymptomatic carriers and reservoirs of these strains in human populations. The aim of this research was to determine the prevalence of strains of MRS among clinically healthy students of the Faculty of Veterinary Medicine in Belgrade. The study was conducted on 100 volunteers: 62 males and 38 females. Given that staphylococci are expected to be found in the highest percentage in the nose and on the armpit skin, the swabs were taken from these regions of each person. Blood agar was innoculated immediately on taking the swabs After the incubation and isolation, the staphylococci were identified to species level. Their susceptibility to methicillin was tested in a disk-diffusion test with cefoxitin. All strains which were found to be resistant to cefoxitin were investigated for the presence of mecA gene with PCR. Staphylococci were isolated in 146 out of the 200 swabs taken: there were 79 nose swabs and 67 axillar swabs positive for these bacteria. Seventeen isolates were resistant to cefoxitin and the presence of the mecA gene was confirmed in seven, four of which were taken from the nose and three from the axillary region. The results of this research show that, being 6%, the prevalence of mecA-positive staphylococci in the population of clinically healthy students of veterinary medicine is significant. The percentage of methicillin-resistant staphylococci was higher in nose than in the axillar region of the students.Rezistencija na meticilin kod stafilokoka smatra se jednim od najopasnijih oblika rezistencije bakterija na antibiotike. Sojevi meticilin rezistentnih stafilokoka (MRS) pripadaju zoonotskim agensima i uzročnici su lokalnih i sistemskih infekcija kod ljudi i životinja, često sa fatalnim ishodom zbog nedostatka efikasne terapije. Ljudi kolonizovani sojevima MRS su asimptomatski nosioci i predstavljaju rezervoare ovih sojeva u humanoj populaciji. Cilj ovog istraživanja je bio da se utvrdi prevalencija izolata MRS kod klinički zdravih studenata Fakulteta veterinarske medicine u Beogradu. U istraživanje je bilo uključeno 100 studenata - dobrovoljaca, 62 muškog i 38 ženskog pola. Brisevi su uzimani iz nosa i pazuha zato što su stafilokoke u najvećem procentu zastupljene u tim regijama. Brisevi su odmah zasejavani na krvni agar. Nakon inkubacije i izolacije, izvršena je identifikacija stafilokoka do vrste. Ispitivanje osetljivosti stafilokoka na meticilin izvedeno je primenom disk difuzione metode sa cefoksitinom. Svi sojevi rezistentni na cefoksitin ispitani su na prisustvo mecA gena metodom lančane reakcije polimeraze (PCR). Od ukupno 200 uzetih briseva izolovano je 146 izolata stafilokoka, 79 iz briseva nosa i 67 iz briseva pazušne regije. Kod 17 izolata ustanovljena je rezistencija na cefoksitin, a kod 7 je utvrđeno prisustvo mecA gena. Četiri mecA pozitivna izolata su poticala iz briseva nosa, a 3 sa kože pazušne regije. Utvrđena prevalencija meticilin-rezistentnih stafilokoka kod klinički zdravih studenata Fakulteta veterinarske medicine od 6%, procenjena je kao značajna. Veća učestalost stafilokoka rezistentnih na meticilin ustanovljena je na sluzokoži nosa u odnosu na kožu pazuha

DETECTION AND HANDLING EXCEPTIONS IN BUSINESS PROCESS MANAGEMENT SYSTEMS USING ACTIVE SEMANTIC MODEL

Although business process management systems (BPM) have been used over the years, their performance in unpredicted situations has not been adequately solved. In these cases, it is common to request user assistance or invoke predefined procedures. In this paper, we propose using the Active Semantic Model (ASM) to detect and handle exceptions. This is a specifically developed semantic network model for modeling of semantic features of the business processes. ASM is capable of classifying new situations based on their similarities with existing ones. Within BPM systems this is then used to classify new situations as exceptions and to handle the exceptions by changing the process based on ASM’s previous experience. This enables automatic detection and handling of exceptions which significantly improves the performance of bpm systems

Development of the mathematical model for surface topography quality determination at the end milling process

As a metal machining process, end milling is the most widely used processes in industry. One of the most important indicators of success in finishing operation is the estetic quality of the surface that is directly connected to the maximal height of uneven surfaces, namely rougness. In process of milling the quality of the machined surface depends of many factors, for example, tool geometry, cutter parallel axis offset and cutter axis tilt, tool deflection due to cutting forces, tool and work piece vibrations etc. This paper presents the development of mathematical model for the determination of the quality of the machined surface topography. The model starts from an ideal trochoid point trajectory on the cutting edge tooth end mill, and then inserts the deviations due to cutter parallel axis offset and cutter axis tilt and gives instructions for the input of other factors that influence on the machined surface quality. Also it compares the values of maximal roughness height with different mill axis positions, and on different mill cross section heights, as well as the differences at up and down milling

Assessment of the integrity of welded pipes

Predmet rada je analiza integriteta zavarenih cevi izrađenih od čelika API J55 visokofrekventnim kontaktnim zavarivanjem (VF). Eksperimentalna ispitivanja mehaničkih osobina osnovnog materijala su izvršena na cevima povučenim iz ekspolatacije posle 70 000 sati rada. Uticaj oštećenja tipa površinske prsline na integritet cevi ispitan je hidrostatičkim pritiskom cevi sa aksijalnom površinskom prslinom u osnovnom materijalu. Ponašanje pri lomu je ispitivano korištenjem modifikovanih kompaktnih epruveta za zatezanje (CT), s početnom prslinom u osnovnom materijalu, zavarenom spoju i zoni uticaja toplote (ZUT). Kritična vrednost faktora intenziteta napona KIc određena je na osnovu kritične vrednosti J integrala JIc. Osim eksperimentalnog istraživanja, na osnovu dobijenih vrednosti za Kr i Sr primenom dijagrama analize loma (FAD) izvršena je procena integriteta zavarenih cevi sa aksijalnom površinskom prslinom na spoljašnjoj površini.The subject of the paper is analysis of the integrity of welded pipes made of API J55 steel by high frequency contact welding (HF). Experimental research on the mechanical properties of the base material was conducted on pipes withdrawn from exploatation after 70 000 hours at service. Defect influence of the surface crack on the integrity of pipes was tested using hydrostatic pressure of pipes with axial surface crack in the base material. Fracture behaviour was tested using modified compact specimen (CT), with the initial crack in the base material, welded joint and heat affected zone (HAZ). Critical value of the tensile strength factors KIc was determined based on the critical value J of the integral JIc. Apart from the experimental research, based on the derived values of Kr and Sr and by applying fracture analysis diagram (FAD) an assessment of the integrity of welded pipes with axial surface crack on the outer surface area was conducted

On finite time delay dependent stability of linear discrete delay systems: Numerical solution approach

U ovom radu razmatra se jedno moguće rešenje bazične nelinearne kvadratne matrične jednačine. To rešenje ima krucijelni značaj u formulisanju posebnog kriterijuma, zavisnog od iznosa čisto vremenskog kašnjenja, za stabilnost na konačnom vremenskom intervalu posebne klase sistema sa kašnjenjem, opisane svojim matričnim modelom x(k+1)=A0(k) + A1x(k-h). U tom smislu izveden je i odgovarajući kriterijum stabilnosti koji uključuje i iznos čisto vremenskog kašnjenja. Mimo toga, posebno je apostrofiran značaj nelinearnog diskretnog matričnog polinoma u stabilnosti sistema. Koristeći matematički formalizam, baziran na Traub-ovom i Bernuli-jevom algoritmu, zaključeno je da sračunavanje dominantnog solventa matričnog polinoma, ne garantuje potrebnu konvergenciju u svim slučajevima, kao sto je slučaj u tradicionalnim numeričkim procedurama. U ovom radu, prezentuje se jedno posebno i jedno opste rešenje, koje važi za slučaj kada se matrični polinom može prikazati u faktorizovanom obliku. Numeričkim primerom ilustrovana je opravdanost predložene procedure.In this paper, a possible solution of the basic nonlinear quadratic matrix equation was proposed. The solution is crucial in the formulation of the particular criteria for the delay-dependent finite time stability of discrete time delay systems represented as x(k+1)=A0(k)+A1x(k-h). The time delay-dependent criteria have been derived. In addition, the significance of the nonlinear discrete polynomial matrix equation is explained. With the use of the mathematical formalism based on the Traub and Bernoulli's algorithms, it was concluded that the computation of the dominant solvent of the matrix polynomial equation does not guarantee a necessary convergence in all cases, unlike in the traditional numerical procedures. In this paper, we presented one particular and one general solution valid in the case when the discrete matrix equation was presented in its factorial form. The numerical computations are performed to illustrate the suggested results

On finite time delay dependent stability of linear discrete delay systems: Numerical solution approach

U ovom radu razmatra se jedno moguće rešenje bazične nelinearne kvadratne matrične jednačine. To rešenje ima krucijelni značaj u formulisanju posebnog kriterijuma, zavisnog od iznosa čisto vremenskog kašnjenja, za stabilnost na konačnom vremenskom intervalu posebne klase sistema sa kašnjenjem, opisane svojim matričnim modelom x(k+1)=A0(k) + A1x(k-h). U tom smislu izveden je i odgovarajući kriterijum stabilnosti koji uključuje i iznos čisto vremenskog kašnjenja. Mimo toga, posebno je apostrofiran značaj nelinearnog diskretnog matričnog polinoma u stabilnosti sistema. Koristeći matematički formalizam, baziran na Traub-ovom i Bernuli-jevom algoritmu, zaključeno je da sračunavanje dominantnog solventa matričnog polinoma, ne garantuje potrebnu konvergenciju u svim slučajevima, kao sto je slučaj u tradicionalnim numeričkim procedurama. U ovom radu, prezentuje se jedno posebno i jedno opste rešenje, koje važi za slučaj kada se matrični polinom može prikazati u faktorizovanom obliku. Numeričkim primerom ilustrovana je opravdanost predložene procedure.In this paper, a possible solution of the basic nonlinear quadratic matrix equation was proposed. The solution is crucial in the formulation of the particular criteria for the delay-dependent finite time stability of discrete time delay systems represented as x(k+1)=A0(k)+A1x(k-h). The time delay-dependent criteria have been derived. In addition, the significance of the nonlinear discrete polynomial matrix equation is explained. With the use of the mathematical formalism based on the Traub and Bernoulli's algorithms, it was concluded that the computation of the dominant solvent of the matrix polynomial equation does not guarantee a necessary convergence in all cases, unlike in the traditional numerical procedures. In this paper, we presented one particular and one general solution valid in the case when the discrete matrix equation was presented in its factorial form. The numerical computations are performed to illustrate the suggested results

Application of electrodialysis for whey demineralization

Elektrodijaliza predstavlja suvremenu membransku metodu koja se u svijetu sve više koristi za demineralizaciju sirutke radi ostvarivanja njene veće primjene u proizvodnji hrane za ljude. Slatko-slani ukus sirutke u prahu i visoki sadržaj mineralnih tvari naročito ograničavaju njeno učešće u proizvodima konditorske industrije i proizvodnji dječje hrane. Na laboratorijskom uređaju vršena je elektrodijaliza svježe, slatke surutke pri različitim gustoćama struje.Elektrodialysis represents a modern contemporary membrane process which beside many other recent applications finds increasing uses in whey desalinization. Demineralized whey powder appears in wide increasing application in many products of food technology and most particularly for children food

Antioxidant potential and protein interactions of four tea plant extracts

Polyphenols are a large group of natural organic compounds mainly found in plants with diverse protective and metabolic functions. Phenolic compounds are well known for their antioxidant properties and the name “antioxidant” is mostly associated with them1. It’s also known that phenolic compounds, especially tannins, interact with proteins in various significant and distinct ways. This study was focused on examining these characteristics on aqueous extracts of tea plants local to Serbia (freshly picked Satureja montana, Mentha spicata, Salvia officinalis and Matricaria chamomilla), which are known to have various amounts and types of phenolic compounds. We examined total concentration of phenolic compounds, tannins, flavonoids, antioxidant activity and interactions with bovine serum albumin and whey protein. It was concluded that S. montana extract had the highest concentration of polyphenols and tannins. Flavonoid concentration was measured using the aluminium-chloride method and it was concluded that S. officinalis had the highest flavonoid content. Antioxidant activities were measured using DPPH, FRAP and ABTS, which are Single Electron Transfer (SET) mechanism-based antioxidant tests and ORAC which is a Hydrogen Atom Transfer mechanism-based antioxidant test. It was concluded that SET mechanism-based antioxidant activities correspond to the total concentration of polyphenols and tannins, which meant that S. montana extract had the highest antioxidant activity. S. officinalis extract exhibited the highest antioxidant activity measured by the ORAC assay, which corresponded to the highest Flavonoid concentration. Interactions between plant extracts and bovine serum albumin were measured via spectrophotometric and spectrofluorimetric titrations. It was concluded that S. montana exhibited most pronounced interactions with the protein. Nature of such interactions is still unknown but using SDS-PAGE it was concluded that proteins exhibit significant structural changes after interacting with plant extracts

Influence of marination on salmonella spp. Growth in broiler breast fillets

The aim of this study was to investigate the influence of marination, on the growth of Salmonella spp. in contaminated broiler breast fillets during storage. In the conducted study, broiler breast fillets were inoculated with a cocktail of different Salmonella strains and afterwards marinated in different solutions of table salt, sodium tripolyphosphate and/or sodium citrate. The total count of Salmonella spp. was examined on the 0, 3rd, 6th and 9th day of storage. Broiler breast fillets salted in 6% solution of table salt were used as the control. Proximate composition and salt content, pH value and a(w) value, were determined as the meat quality parameters and parameters which can affect environmental conditions for bacterial growth, as well. Compared to initial contamination, Salmonella spp. count in marinated and salted fillets did not change significantly (p 0.05) on protein and fat content in broiler meat. According to the results obtained it can be concluded that marination of broiler breast fillets in solutions containing table salt, sodium trpolyphosphate and/or citrate, in some way, can prolongate the lag phase of Salmonella spp. growth, where sodium citrate is more effective than sodium tripolyphosphate

Chemical composition, antioxidant and antigenotoxic activities of different fractions of Gentiana asclepiadea L. roots extract

The aim of this study was to evaluate the antioxidant and antigenotoxic activities of chloroform, ethyl acetate and n-butanol fractions obtained from Gentiana asclepiadea L. roots methanolic extract. The main secondary metabolites sweroside, swertiamarin and gentiopicrine were quantified in G. asclepiadea root extracts using HPLC-DAD analysis. Amount of total phenols, flavonoids, flavonols and gallotannins was also determined. The antigenotoxic potential of extracts from roots of G. asclepiadea was assessed using the standard in vivo procedure for the detection of sex linked recessive lethal mutations in Drosophila melanogaster males treated with ethyl methanesulfonate (EMS). The results showed that the most abundant secoiridoid in G. asclepiadea roots was gentiopicrine and its content in the n-butanol fraction (442.89 mg/g) was the highest. Among all extracts, ethyl acetate fraction showed the highest antioxidant activity, as well as total phenolics (146.64 GAE/g), flavonoids (44.62 RUE/g), flavonols (22.71 RUE/g) and gallotannins (0.99 mg GAE/g) content. All the fractions showed antioxidant activity using in vitro model systems and the results have been correlated with total phenolics, flavonoids, flavonols and gallotannins content. In addition to antioxidant activity, G. asclepiadea root extract fractions possess an antigenotoxic effect against DNA damage induced by alkylation with EMS. The antioxidant activity exhibited by G. asclepiadea depended on the phenolic compounds content of the tested extracts, while there was no significant difference in the antigenotoxic potential between fractions