Tick-Borne Encephalitis

Tick-borne encephalitis (TBE) is an important central nervous system infection in Europe and Asia. It is caused by three subtypes of TBE virus (TBEV): European, Siberian and Far-Eastern, belonging to the genus Flavivirus. TBE is delineated by three criteria: the presence of clinical signs of meningitis, meningoencephalitis or meningoencephalomyelitis; cerebrospinal fluid pleocytosis (>5 × 106 cells/L); and demonstration of a recent infection with TBEV by the presence of specific serum IgM and IgG antibodies or IgG seroconversion. Imaging of the brain and spinal cord has a low sensitivity and specificity, but it is useful for the differential diagnosis. Clinical course and outcome of TBE depend on the subtype of TBEV (the disease caused by the European subtype has a milder acute course and a more favorable long-term outcome than the disease caused by the other two virus subtypes), age of patients (increasing age is associated with more severe acute course and poorer outcome) and probably on some host genetic factors. Due to relatively severe clinical course combined with the absence of etiologic treatment, considerable proportion of patients with incomplete recovery after acute illness, and increasing incidence, TBE represents a growing (public) health problem that could be substantially reduced with vaccination

Probability calculations of voltage conditions and load flow in power systems with included FACTS devices

Doktorska disertacija obravnava področje verjetnostne analize napetostnih razmer in pretokov energije v radialnih omrežjih z vključenimi hitrimi regulabilnimi napravami. Zaradi vključevanja novih naprav v elektroenergetski sistem (EES) se ta neprestano razvija. V zadnjem času je razvoj usmerjen v smeri množičnega vključevanja obnovljivih virov v sistem, ki pa imajo slabo lastnost, da je njihov obratovalni režim pogojen z vremenskimi razmerami in je bolj ali manj nenapovedljiv. Zaradi tega se vse pogosteje uporablja verjetnostni pristop k analizi napetostnih razmer in pretokov energije. Ima pa nepoznavanje obratovalnih razmer za posledico še potrebo po ustrezni regulaciji napetostnih razmer. V nekaterih starejših transformatorskih postajah so vključeni transformatorji, ki omogočajo preklope le v času izključitve. Ker pa se proizvodnja s strani sončnih elektrarn spreminja dnevno, bi bilo treba v takšnih sistemih dnevno spreminjati odcepe. Zato se kot ena izmed smiselnih rešitev postavlja vključitev hitrih regulabilnih naprav v sistem za namen regulacije ustreznih napetostnih razmer. Doktorska disertacija, ki temelji na reševanju problematike napetostnih razmer v radialnih omrežjih z vključevanjem hitrih regulabilnih naprav v sistem in z verjetnostno analizo obratovalnih stanj sistema je v grobem sestavljena iz štirih sklopov. V prvem sklopu so opisani trifazni modeli najbolj pogosto uporabljenih naprav ter metode za izračun napetostnih razmer in pretokov energije. V drugem sklopu smo se dotaknili verjetnostnega računa, osnov statistike in metod za verjetnostni izračun napetostnih razmer in pretokov energije. V tem delu je predstavljena tudi nadgradnja obstoječe metode kumulant za verjetnostni izračun napetostnih razmer in pretokov energije, ki omogoča verjetnostni izračun v radialnih omrežjih. Obstoječa metoda namreč zaradi singularnosti občutljivostne matrike ni uporabna v radialnih omrežjih. V tretjem sklopu doktorska disertacija predstavlja nove modele hitrih naprav, ki so primerni za uporabo v radialnih sistemih v trifazni analizi napetostnih razmer in pretokov energije. Modeli naprav temeljijo na reševanju sistema nelinearnih enačb znotraj reševanja sistema linearnih enačb. S sistemom nelinearnih enačb so zapisane lastnosti hitre regulabilne naprave, sistem linearnih enačb pa predstavljajo enačbe za padce napetosti. Predstavljen je model vzdolžne veje, katerega zastopnik je SSSC, model prečne veje, ki ga simbolizira naprava STATCOM, in njuna kombinacija, ki jo zastopa UPFC. V četrtem sklopu pa so prikazani primeri uporabe novih modelov hitrih regulabilnih naprav in nove nadgrajene metode kumulant. Modele hitrih regulabilnih naprav smo preskusili na treh standardnih testnih sistemih, tj. IEEE 34, IEEE 37 in IEEE 123 vozliščnem testnem sistemu. Vsi trije sistemi so radialni in se za izračun napetostnih razmer ter pretokov energije uporablja U-I metoda. Pri testiranju modelov posamezne naprave smo opazovali število iteracij, potrebnih za dosego želene točnosti rezultata, napetostni odziv sistema na vsiljeno jalovo moč in modele dodatno preizkusili z nadomestno impedanco, ki jo je predstavljala hitra regulabilna naprava. Prav tako smo na standardnih trifaznih sistemih z vključenimi nelinearnimi napravami prikazali uporabo nove nadgrajene metode za verjetnostni izračun napetostnih razmer in pretokov energije. Rezultate verjetnostnih napetostnih razmer in pretokov energije smo podali v obliki tabel in jih primerjali z rezultati, pridobljenimi z metodo Monte Carlo. Na podlagi analize smo ugotovili, da so rezultati obeh metod primerljivi, zato se lahko za verjetnostni izračun napetostnih razmer in pretokov energije v radialnih omrežjih uporabi nova nadgrajena metoda, ki je v primerjavi z metodo Monte Carlo bistveno hitrejša.This doctoral thesis deals with probabilistic power flow in radial distributional systems which include flexible alternating current transmission system devices (FACTS devices). Due to the integration of new devices into the electric power system (EPS), the system is constantly evolving. Recently, development has been oriented towards the massive integration of renewable power plants into the system, but these have the disadvantage that their operating diagram is subjected to weather conditions and inconveniences. As a result, the probabilistic approach is being used increasingly to analyse voltage conditions and power flows. The lack of knowledge of the operating diagram of renewable power plants has resulted in the need for appropriate regulation of voltage conditions. Some of the older substations include transformers which allow tap changes only when disconnected. However, since the production of solar power plants varies daily, it would be difficult to change the taps in such systems. Therefore, a reasonable solution is to include FACTS devices in the system for the purposes of regulating voltage conditions. This doctoral thesis, which presents the solution to the problem of voltage conditions in radial distributional systems by integrating FACTS devices and the probabilistic analysis of operating conditions into the system, is roughly composed of four parts. The first part describes the three-phase models of the most commonly used devices and the methods for calculating voltage conditions and power flows. In the second part, the basic statistics and probability methods for calculating voltage conditions and power flows are illustrated. This section presents the upgrading of the existing method of cumulants for calculating the probabilistic power flow that is suitable for use in radial networks. Due to the singularity of the sensitivity matrix, the basic cumulant method is unsuitable for use in radial networks. The third part of the thesis presents new models of FACTS devices that are suitable for use in three-phase power flow calculations in radial systems. The models are based on the solving of a system of nonlinear equations within the system of linear equations. The system of nonlinear equations describes the features of FACTS devices, while the system of linear equations represents voltage drops. The thesis presents the model of the static synchronous series compensator (SSSC), the static synchronous compensator (STATCOM) and the unified power flow controller (UPFC). In the fourth part, new models of FACTS devices and the new upgraded method of cumulants are evaluated. The models of FACTS devices were tested on three standard test systems, i.e. IEEE 34, IEEE 37 and IEEE 123 node test systems. All three systems are radial, so the U-I method was used for power flow calculation. The number of iterations required to achieve the desired accuracy and voltage response was observed when testing the FACTS devices. The reactance of FACTS devices was calculated from mathematical results and used in simulations to verify the models. The new upgraded method for probability power flow calculations was tested on standard three-phase systems incorporating FACTS devices. The results of the probabilistic power flow are presented in tabular form and compared with the results obtained by the Monte Carlo method. Based on the analysis, it has been established that the results of the two methods are comparable, and therefore the new upgraded method, which is much faster than the Monte Carlo method, may be used for probability power flow calculations in radial networks

Antimicrobial Resistance of Common Zoonotic Bacteria in the Food Chain: An Emerging Threat

Antimicrobial resistance in the food chain is currently a subject of a major interest. The excessive use or rather misuse of antimicrobials coupled with a poor hygiene in the food production chain has led to a rise of resistant zoonotic bacteria, commonly transmitted by food. They pose a serious threat to human health. Campylobacteriosis is the leading bacterial food-borne illness and most commonly reported zoonosis in humans in the European Union for more than a decade. Salmonellosis is most frequently diagnosed in food-borne outbreaks. Fluoroquinolones are considered as critically important for treatment of severe cases of both zoonoses in humans. Due to an extremely prevalent resistant isolates, especially from broilers and meat, also the treatment of human Campylobacter infections with fluoroquinolones has become compromised. Salmonella isolates from poultry and poultry meat tend to be highly resistant to fluoroquinolones as well. Beside the resistance to this group of antibiotics, the threat of multiple drug resistant (MDR) Campylobacter and Salmonella strains is discussed in the light of most recent reports of animal, food and human clinical surveillance systems

The influence of population size of gram-negative psychrotrophs on survival during pasteurization

Na tri izolata vrste Pseudomonas fluorescens izolirana iz pasteriziranog mlijeka proučavali smo utjecaj veličine populacije na kinetiku odumiranja za trajanje pasterizacije mlijeka (63 °C/30 min). Bez obzira na veličinu populacije i pojedine izolate, do najveće redukcije broja stanica došlo je u vrijeme dogrijavanja uzroka do 63 °C (4 min.). Ako je početna populacija bila <10^4 BK/ml ustanovili smo sto postotnu letalnost. Nakon 48 sati skladištenja (7 °C) i u tim uzorcima pasteriziranog mlijeka zapazili smo prisustvo živih stanica.The influence of initial population size on destruction kinetics during milk pasteurization (63 °C/30 min) was studied relative to three Pseudomonas fluorescens isolates from pasteurized milk. The greatest reduction of viable cells was observed during first stage of milk pasteurization to reaching final temperature (63 °C/4 min) for all isolates and every starting population size. When inital population size attained <10^4 CFU/ml lethality determined immediately after pasteurization was 100%. Despite this fact viable cells were observed in all samples of pasteurized milk stored 48 hours at 7 °C

In-situ inhibicija Staphylococcus aureus bakterijama mliječne kiseline iz dva tradicionalna slovenska sira proizvedena od sirovog mlijeka

Bacteriocin(s) producing lactic acid bacteria naturally present in traditional cheeses represent an inexhaustive pool of microbes with safeguarding potential. Some bacteriocins produced by cheese lactic acid bacteria were already described as successful anti-staphylococcal agents. The presence of genes for bacteriocins with potential anti-staphylococcal activity was also demonstrated in two Slovenian traditional raw milk cheeses, “Tolminc” and “Kraški ovčji sir”. Same bacteriocin genes were also detected in viable lactic acid bacteria consortia’s isolated from “bacteriocin positive cheeses” on Rogosa, M17 and CATC agar media. The aim of the research was to elucidate whether or not this particular cheese consortia, in which bacteriocin genes were detected, actually exhibit anti-staphylococcal activity in milk and/or cheese. For this purpose different cheese consortia were selected in relation to versatility of detected bacteriocin genes and used to perform challenge tests against Staphylococcus aureus in milk and cheese. In milk following the time/temperature regime of traditional cheese production all cheese consortia effectively inhibited growth of Staphylococcus aureus in the range of app. 2 to 3 log. In cheese the inhibition of staphylococci was less pronounced but still evident since inhibition of app. 1.5 log was detected. Sole inhibition by lactic acid production was ruled out while linking inhibition directly to bacteriocin production would take some additional work.Bakterije mliječne kiseline (BMK), prirodno prisutne u tradicionalnim sirevima, predstavljaju neograničen izvor mikroba sa zaštitnim svojstvima. Za neke bakteriocine, koje proizvode BMK iz sira, antistafilokokna svojstva već su poznata. Prisutnost gena za bakteriocine s antistafilokoknim svojstvima potvrđena je u dva tradicionalna slovenska sira iz sirovog mlijeka; to su sir “Tolminc” i “Kraški ovčji sir”. Prisutnost istih bakteriocina potvrđena je i kod bakterija mliječne kiseline, koji su izolirali iz tih sireva na agar podlogama Rogosa, M17 i CATC. Cilj je bio provjeriti da li izolirani sojevi bakterija mliječne kiseline, koji nose gene za bakteriocine, zaista pokazuju antistafilokokna svojstva u mlijeku i/ili siru. Na temelju prisutnih gena za bakteriocine ispitana je antimikrobna aktivnost združene kulture bakterija mliječne kiseline prema bakteriji Staphylococcus aureus u mlijeku i siru. U mlijeku kojeg smo podvrgnuli vremensko-temperaturnom režimu proizvodnje tradicionalnih sireva, združena kultura bakterija mliječne kiseline inhibirala je rast bakterije Staphylococcus aureus u rasponu od 2 do 3 logaritamske jedinice. U siru je inhibicija stafilokoka bila nešto manje izražena, ali još uvijek očita sa 1,5 logaritamskih jedinica slabijim rastom S. aureus nego u kontrolnom siru. Učinak inhibicije izazvane mliječnom kiselinom bio je isključen, ali bi bilo potrebno izvesti još dodatna ispitivanja, da se utvrdi izravno inhibicijsko djelovanje bakteriocina na stafilokoke

Kompetitivna prednost bakteriocinogenih sojeva konzorcija bakterija mliječne kiseline izoliranih iz sira proizvedenog od sirovog mlijeka

The presence of gene determinants for different bacteriocins has been already demonstrated in traditional Slovenian types of raw milk cheeses ‘Tolminc’ and ‘Kraški’. These genes were present also in the cultivable microbiota. In this research the aim was to establish how the presence of gene determinants for bacteriocins in microbial consortia is reflected in its antimicrobial activity. In addition, one of the goals was to determine whether the strains that carry gene determinants for bacteriocins have any competitive growth advantage in microbial population. Microbial consortium of ‘Tolminc’ cheese was propagated in milk and examined at the end of propagation its antimicrobial activity and the presence of gene determinants for bacteriocins. Comparison of the results obtained before and after propagation leaded to the conclusion that most of the strains possessing gene determinants for bacteriocins were unable to persist during propagation. The strains which did persist during propagation carried gene determinants for enterocins P, L50B and cytolysin. Antimicrobial activity of consortium before and after propagation was not substantially different and cannot be attributed to any of detected bacteriocins.Prisutnost genskih determinanti za stvaranje različitih vrsta bakteriocina već je ranijim istraživanjima utvrđena u slovenskim ovčjim sirevima “Tolminac” i “Kraški sir” koji se proizvode na tradicionalan način. Isti geni za izoliranu mikrobnu populaciju (konzorcij) također su potvrđeni i u kultiviranim uvjetima. U ovom radu pokušalo se utvrditi kako se prisutnost tih genskih determinanti u mikrobnom konzorciju odražava na njegovu antimikrobnu aktivnost. Osim toga, utvrđivao se i utjecaj bakterijskih sojeva koji nose gene za stvaranje bakteriocina na kompetitivnost rasta u mješovitoj populaciji. Mikrobni konzorcij izoliran iz sira “Tolminac” propagiran je u mlijeku 10 dana, nakon čega je utvrđena antimikrobna aktivnost kulture i prisutnost genskih determinanti za stvaranje bakteriocina. Usporedbom rezultata za sposobnost stvaranja bakteriocina prije i nakon precjepljivanja u mlijeku, utvrđen je gubitak te sposobnosti za većinu izoliranih sojeva. Sojevi koji su izdržali ponovljena precjepljivanja u mlijeku nosili su genske determinante za bakteriocine: enterocin P, enterocin L50B i citolizin. Antimikrobna aktivnost konzorcija prije i nakon precjepljivanja nije se značajno razlikovala te se ne može pripisati niti jednom od u ovom pokusu potvrđenih bakteriocina

Utjecaj antibiotika na bakterije mliječne kiseline probavnog sustava

Lactic acid bacteria (LAB) are common inhabitants of the gastrointestinal (GI) tract and have important role in maintaining the equilibrium of GI flora, which can be influenced by various factors like diets, antimicrobials and stress. Minimal inhibitory concentrations (MIC) and minimal bactericidal concentrations (MBC) of 6 antibiotics, commonly used in human medicine for 8 selected lactobacilli strains were determined by macrodilution and microdilution methods in liquid media and by diffusion method on agar plates. The effects of Penicillin G and Ampicillin on intestinal LAB were tested in vivo on mice as well. Lactobacilli were sensitive to Penicillin G, (penicillines and their derivatives) and Erythromycin (macrolides) by in vitro testing. Clyndamycin (pyranosid) showed moderate inhibitory effect. All lactobacilli strains were resistant to Kanamycin and Neomycin (aminoglycosides), while L. salivarius IM 124 has shown extra resistance to Erythromycin and Clyndamycin. The influence of orally administered Ampicillin showed no significant influence on LAB count in mice faeces. The effect of Penicillin G on mice LAB total count was significant, while no effect of orally administered lactobacilli was determined.Bakterije mliječne kiseline (BMK) su uobičajeni sudionici crijevne mikroflore ljudi i životinja. One imaju važnu ulogu u održavanju ravnoteže gastrointestinalne (GI) flore, na koju mogu utjecati različiti faktori poput prehrane (hrane) antimikrobnih supstancija i stresa. Pomoću makrodilucijske i mikrodilucijske metode u tekućoj podlozi te metode difuzije na agar pločama, određene su minimalne inhibicijske koncentracije (MIC) i minimalne baktericidne koncentracije (MBC) šest (6) antibiotika koji se svakodnevno upotrebljavaju u humanoj medicini za 8 sojeva BMK. Učinak penicilina G i ampicilina na BMK probavnog sustava testiran je također in vivo na laboratorijskim miševima. Laktobacili su se pokazali osjetljivim na penicilin G, na ampicilin (derivati penicilina) i na eritromicin (makrozidni antibiotik) prilikom testiranja in vitro. Klindamicin (piranozidni antibiotik) je pokazao umjereni inhibicijski učinak. Svi sojevi BMK pokazali su se otpornim na kanamicin i neomicin (aminoglikozidni antibiotici). Od svih testiranih BMK posebno se otpornim na eritromicin i klindamicin pokazao L. salivarius IM 124. Učinak oralno primjenjenog ampicilina, na broj BMK u stolici miševa nije statistički dokazan. Utjecaj penicilina G na broj BMK kod miševa pokazao se signifikantnim, ali to nije bio slučaj s oralno primijenjenim BMK