Identification and molecular characterization of Chryseobacterium vrystaatense ST1 isolated from oligomineral water of southeast Serbia

The isolation and molecular characterization of bacterial strains isolated from water sources in the Vlasina Mountain in southeast Serbia, confirmed the presence of a new species Chryseobacterium vrystaatense ST1. This Gram- negative species showed an extremely low level of biochemical reactivity in biochemical tests. The gene for 16S rRNA was amplified by PCR using universal primers and sequenced. Comparison of 16S rRNA gene sequence and phenotypic features indicated that the isolate ST belonged to Chryseobacterium vrystaatense. A BLAST search of sequenced 1088 nucleotides of the 16S rRNA gene with all sequences deposited in the NCBI collection showed the highest similarity (98%) with the strain Chryseobacterium vrystaatense sp. nov., designated as strain R-23533. The very high homology of these two strains allowed classification of our strain at the species level, but some differences indicate, and indirectly confirm, that the isolate ST is an authentic representative. On the basis of these results, we could conclude that Chryseobacterium vrystaatense ST was for first time isolated in Serbia, which is particularly important when one bears in mind that there are only three sequences of this species deposited in the NCBI collection

Identification and molecular characterization of Chryseobacterium vrystaatense ST1 isolated from oligomineral water of southeast Serbia

The isolation and molecular characterization of bacterial strains isolated from water sources in the Vlasina Mountain in southeast Serbia, confirmed the presence of a new species Chryseobacterium vrystaatense ST1. This Gram- negative species showed an extremely low level of biochemical reactivity in biochemical tests. The gene for 16S rRNA was amplified by PCR using universal primers and sequenced. Comparison of 16S rRNA gene sequence and phenotypic features indicated that the isolate ST belonged to Chryseobacterium vrystaatense. A BLAST search of sequenced 1088 nucleotides of the 16S rRNA gene with all sequences deposited in the NCBI collection showed the highest similarity (98%) with the strain Chryseobacterium vrystaatense sp. nov., designated as strain R-23533. The very high homology of these two strains allowed classification of our strain at the species level, but some differences indicate, and indirectly confirm, that the isolate ST is an authentic representative. On the basis of these results, we could conclude that Chryseobacterium vrystaatense ST was for first time isolated in Serbia, which is particularly important when one bears in mind that there are only three sequences of this species deposited in the NCBI collection

Transport of silver nanoparticles from nanocomposite Ag/alginate hydrogels under conditions mimicking tissue implantation

The aim of this work was to assess phenomena occurring during AgNP transport from nanocomposite Ag/alginate hydrogels under conditions relevant for potential biomedical applications as antimicrobial soft tissue implants. First, we have studied AgNP migration from the nanocomposite to the adjacent alginate hydrogel mimicking soft tissue next to the implant. AgNP deposition was carried out by the initial burst release lasting for similar to 24 h yielding large aggregates on hydrogel surfaces and smaller clusters (similar to 400 nm in size) inside. However, the overall released content was low (0.67%) indicating high nanocomposite stability. In the next experimental series, release of AgNPs, 10-30 nm in size, from Ag/alginate microbeads in water was investigated under static conditions as well as under continuous perfusion mimicking vascularized tissues. Mathematical modeling has revealed AgNP release by diffusion under static conditions with the diffusion coefficient within the Ag/alginate hydrogel of 6.9x10(-19) m(2) s(-1). Conversely, continuous perfusion induced increased AgNP release by convection with the interstitial fluid velocity estimated as 4.6 nm s(-1). Overall, the obtained results indicated the influence of hydrodynamic conditions at the implantation site on silver release and potential implant functionality, which should be investigated at the experimentation beginning using appropriate in vitro systems

Molecular and biochemical characterization of pseudomonas putida isolated from bottled uncarbonated mineral drinking water

Pseudomonas putida belongs to a group of opportunistic pathogens that can cause disease in people with weakened or damaged immune systems. Some strains have medical significance, and for most ingestion is not the primary route of infection. If water used by predisposed subjects is contaminated by P. putida, they may become ill. The aim of this work was the biochemical and molecular characterization of strain ST3 of P. putida isolated from non-carbonated bottled drinking water from Jakov Do 4 on Mt. Vlasina. Characterization of P. putida was performed to assess the risk to human health of the indigenous strains present in the water. Biochemical characterization of strains was performed using the manual identification system ID 32 GN (BioMerieux). Identification was obtained using the database identification software ATB System (Bio-Merieux). Molecular characterization was performed by PCR amplification and 16S rDNA "thermal cycling sequencing". Biochemical identification of the strain ST3 was accurate (Id = 99.8%). Comparing the sequences obtained for strain ST3 with NCBI gene bank sequences for 16S rRNA, the highest similarity of our strain (96% identity) with a strain of P. putida, designated as biotype A (gi vertical bar 18076625 vertical bar emb vertical bar AJ308311.1 vertical bar.PPU308311) isolated in New Zealand, was obtained. While comparison with the NCBI collection of all deposited sequences showed that the 16S rRNA gene sequence of strain ST3 has very high homology, it is not identical, indicating indirectly that strain ST-3 is an indigenous strain

Institutional framework for financial supervision in European Union

Државе су, и то готово од самог настанка првих облика банкарства у савременом смислу, препознале да постоји јавни интерес у обезбеђивању стабилног и сигурног банкарског пословања, те да га је неопходно у извесној мери уредити, али и надзирати активности банака. Разлози који оправдавају интервенцију државе у области пословања банака и других финансијских институција су бројни, али би се могла издвојити и два кључна: а) потреба да се обезбеди боља информисаност депонената, односно других корисника финансијских услуга; б) потреба да се обезбеди стабилност финансијског система. Међутим, са интернационализацијом пословања банака, а затим и других финансијских институција – обезбеђење стабилности финансијског система постаје циљ који ниједна држава не може остварити сама за себе, односно без интеракције с државама у којима филијале или огранке имају финансијске институције које послују на њеној територији. Из тог разлога супервизија ових институција постаје питање које превазилази национални значај и националне оквире. Тренд успостављања и развоја институционалних облика сарадње држава у области супервизије финансијских институција који се јавио на ширем међународном плану није заобишао ни Европску унију. Напротив, институционални оквири за вршење ове супервизије су се под окриљем Европске уније развијали још динамичније и интензивније пошто је у условима унутрашњег тржишта, са заједничком валутом, било још очигледније да та супервизија не може бити (бар не у потпуности) препуштена само државама чланицама јер озбиљнији пропусти у њеном вршењу потресају и саме темеље Европске уније.It is almost since the occurrence of the first forms of banking in the modern sense that states have recognized public interest in ensuring safe and sound banking operations and hence, the necessity to regulate and supervise banks' activities to a certain extent. There are numerous reasons that justify state intervention in the field of banking operations and the operations of other financial institutions, but they could all be summed up in the following two: a) the necessity to ensure that depositors and other consumers of financial services are better informed; b) the necessity to ensure the stability of financial system. However, along with an internationalization of banking and financial business in general, ensuring the stability of financial system has become an objective that the state can no longer achieve by itself, without interaction with other states in which financial institutions that operate in its territory also have their branches and subsidiaries. Due to this fact, supervision of financial institutions has become an asset that transcends national relevance and frameworks. The trend of establishment and development of institutional forms of cooperation between states in the field of financial supervision at the wider international level did not bypass the European Union. On the contrary, the institutional frameworks for the supervision of financial institutions were developed under the auspices of the European Union even more dynamically and more intensely as it soon became obvious, with the Internal Market and Single Currency, that leaving supervision to the exclusive competence of Member States could not be afforded because serious omissions in its exercise shook the very foundations of the European Union itself. Institutional forms of Member States' cooperation in the field of financial supervision have developed gradually, along with increasing integration, leading up to the creation of the Banking union within the European Union that we are the witnesses of. Establishment of the European System of Financial Supervision is one of the most important steps forward in this process

Electrochemical deposition and characterization of Ni-W alloys

Kinеtikа еlеktrоhеmiјskоg tаlоžеnjа Ni-W lеgurа iz аmоniјаčnо-citrаtnоg еlеktrоlitа ispitivаnа је pоlаrizаciоnim mеrеnjimаnа rоtirајućој disk еlеktrоdi. Prisustvо i rеlаtivnа kоncеntrаciја rаzličitih kоmplеksnih vrstа је ispitivаnа еlеktrоnskоm аpsоrpciоnоm spеktrоfоtоmеtriјоm. Sаstаv lеgurа i iskоrišćеnjе struје tаlоžеnjа su ispitivаni u zаvisnоsti оd sаstаvа еlеktrоlitа, pH vrеdnоsti, hidrоdinаmičkih uslоvа, gustinе struје i pаrаmеtаrа pulsirајućе struје (frеkvеnciје i оdnоsа vrеmеnа pаuzе i pulsа). Rаzličiti kоmplеksni јоni su prisutni u еlеktrо-litu оd kојih su zа tаlоžеnjе lеgurе nајznаčајniјi prоtоnоvаni vоlfrаmаtnо-citrаtni kоmplеks i аmоniјаčnо-citrаtni kоmplеks niklа. Rеаkciја rеdukciје prоtоvаnih vоlfrаmаtnо-citrаtnih kоmplеksа је difuziоnо kоntrоlisаnа i tаlоžеnjе mеtаlа sе оdigrаvа sаmо u prisustvu аmоniјаčnо-citrаtnih kоmplеksа niklа. Тоkоm еlеktrо-hеmiјskоg tаlоžеnjа Ni-W lеgurа nikаl sе prvеnstvеnо tаlоži iz аmоniјаčnо-citrаtnih kоmplеksnih јоnа. Pri niskim pоlаrizаciјаmа rеdukciја је аktivаciоnо kоntrоlisаnа, а pri nеgаtivniјiјim pоtеnciјаlimа difuziоnо-rеаkci-оnо kоntrоlisаnа, pоštо је mаlа kоncеntrаciја rеdukuјućеg kоmplеksа i mаlа brzinа njеgоvоg stvаrаnjа iz drugih kоmplеksа. Моlski udео vоlfrаmа u dоbiјеnim lеgurаmа је оdrеđеn оdnоsоm brzinа dvе rеаkciје rеdukciје mеtаlnih kоmplеksа i iznоsi оd 0,06 dо 0,25. Uticај pаrаmеtаrа pulsirајućе struје nа mоrfоlоgiјu i udео vоlfrаmа u dоbiјеnim lеgurаmа prаti оpšti trеnd, prеtpоstаvlјеn tеоriјskim mоdеlоm nеstаciоnаrnе difuziје, аli i kоmplеksniје kаrаktеristikе. Еlеktrоhеmiјskо tаlоžеnjе Ni-W lеgurе је znаčајnо s оbzirоm nа spеcifičnе kаrаktеristikе i mоguću prаktičnu primеnu prеvlаkа. Lеgurе tаlоžеnе pulsirајućоm struјоm su rаvniје, vеćе tvrdоćе, pоsеbnо nаkоn tеrmičkоg trеtmаnа nа pоvišеnim tеmpеrаturаmа, u оdnоsu nа lеgurе tаlоžеnе kоnstаntnоm struјоm. Pоlаrizаciоnе krivе аnоdnоg rаstvаrаnjа i kаtоdnih rеаkciја snimlјеnе su u zаvisnоsti udеlа vоlfrаmа u еlеktrоhеmiјski tаlоžеnim lеgurаmа Ni-W, u sulfаtnim rаstvоrimа, pH vrеdnоsti оd 0 dо 14. Zаvisnоst kоrоziоnоg pоtеnciјаlа i dоbiјеnih struја оd mоlskоg udеlа vоlfrаmа i pH vrеdnоsti еlеktrоlitа ukаzuје dа sе nа pоvršini lеgurе, tоkоm stајаnjа nа pоtеnciјаlu оtvоrеnоg kоlа i tоkоm аnоdnе pоlаrizаciје u ispitivаnоm rаstvоru, stvаrа bаriјеrni slој kојi sprеčаvа dаlје rаstvаrаnjе lеgurе.Kinetics of the electrochemical deposition Ni-W alloys from ammonia-citrate electrolyte was studied by polarization measurements with a rotating disc electrode. Presence and relative concentrations of different complex species was employed by UV-VIS spectroscopy. The deposit composition and current efficiency were measured as a function composition of the electrolyte for deposition, pH, hydrodynamic condition, current density of deposition and the variables of pulsating current (frequency and ratio of off time to on time). Different complex species are found in the electrolyte, the most important for the alloy deposition process being the protonated tungstate-citrate complex and ammonia-citrate complex of nickel. The electrochemical reduction of the protonated tungsten-citrate complexes is diffusion controlled and the deposition of the metal occurs only in the presence of the ammonia-citrate complexes of nickel. During the electrochemical deposition of Ni-W alloys Ni is deposited primarily from the ammonia-citrate complex. At low overpotentials the reaction is activation controlled, while at more negative potentials diffusion/reaction control takes over, because of the low concentration of the electroactive species and low rate of its formation from other complexes. The composition of the alloy is determined by the ratio of the rates of the two reduction reactions of metallic ions, tungsten content were from 6 to 25 mol %. The effect of pulsating current parameters on the morphology of the alloy as well as on the tungsten content obtained in this work follow a general trend predicted by the non-steady state diffusion model, but show a some more complex behavior. Electrochemical deposition of Ni-W alloy is interesting for plating practice, because of some characteristic properties and possible practical applications of the deposit. The pulse deposited alloys were better smoothness, microhardness, especially after ageing at high temperatures, than alloy obtained by constant c.d. Polarization curves of anodic dissolution and cathodic reactions of electrodeposited Ni-W alloys, different content of tungsten, were determined in sulphate solutions, the pH values were varied from 0 to 14. The dependence of corrosion potential and obtained current on content of tungsten and pH indicated that at the alloy surface, during ageing and anodic polarization in employed solution, forming barrier layer, which to protected the alloy from dissolution

Characterization of NTC thick film thermistor paste Cu0.2Ni0.5Zn1.0Mn1.3O4

A powder of Cu0.2Ni0.5Zn1.0 Mn1.3O4 composition for custom thermistor was prepared by using the respective mixture of metal oxides and solid state reaction at 1000 °C/4h in air. The obtained thermistor powder was milled in the planetary ball mill and agate mill for a prolonged time to achieve submicron powder. The prepared thermistor powder was further characterized by using XRD and SEM techniques. After that, the thermistor powder was pressed into small disc-shaped samples and sintered at 1150 °C/2h. The sintered samples were also characterized by using XRD and SEM. The main electrical properties such as nominal resistance R and thermistor exponential factor B were measured in the climatic test chamber. After that, the thick film paste was prepared using the same powder, an organic vehicle and a glass frit. The paste was printed on alumina substrate, dried at 150 °C /30 min and sintered in air at 850 °C /10 min in a hybrid conveyor furnace. Planar electrodes were printed on the sintered NTC thermistor layer using PdAg thick film paste. The electric properties of the sintered thick film thermistor were also measured in the climatic test chamber. The obtained results were used for development of novel self-heating thermistor applications

Physico-chemical Properties of Corn Extrudates Enriched with Tomato Powder and Ascorbic Acid

The aim of this research was to investigate the influence of the addition of tomato powder (TP) to corn grits at levels 4, 6 or 8 % and the addition of ascorbic acid (AA) at levels 0.5 and 1 %, on total polyphenol content (PF), and antioxidant activity of the extrudates. The hardness and the expansion ratio of the extruded products were also tested. Mathematical models that describe the influence of additives on the mentioned properties were also determined. Extrusion was performed at two temperature regimes: 135/170/170 °C and 100/150/150 °C. Lower temperature regime led to increased hardness and the expansion of extrudates. The addition of tomato and AA led to decreased hardness and the expansion at both temperature regimes. The addition of tomato increased PF and AA compared with pure corn extrudates. Greater degradation of PF and AA was at lower temperature regime. High correlation between PF and AA was demonstrated at both extrusion temperatures

Model-based catalyst selection for the oxidative coupling of methane in an adiabatic fixed-bed reactor

Adiabatic operation of catalytic fixed-bed reactors for oxidative coupling of methane (OCM) has been simulated using a detailed microkinetic and reactor model. For several catalysts (1%(wt) Sr/La2O3, 10%(wt) La-20%(wt) Sr/CaO, 4%(wt) Sn-2%(wt) Li/MgO, and 12%(wt) Mn-20%(wt) Na2WO4/SiO2), diverse in activity and selectivity toward C2+ products, operating conditions have been determined that maximize C2+ yield at low inlet temperature T-0 (<< 923 K). A prior analysis of light-off curves served as a guideline for optimal operating temperature ranges for each catalyst. Imposing a maximum temperature in the reactor (T-max <= 1273 K) suggested a limit for the catalytic performances, corresponding to 13% CH4 conversion and 61% C2+ selectivity at the reactor outlet for an active (T-0 = 723 K) Sr/La2O3 catalyst, and an improved 19% CH4 conversion and 82% C2+ selectivity for a less active (T-0 = 853 K) NaMnW/SiO2 catalyst. The obtained results indicated catalyst selectivity, rather than activity, as the key parameter for an industrially relevant adiabatic OCM process