Upotreba bakterijskih sojeva koji sintetiziraju bakteriocine u proizvodnji mliječnih prerađevina

Lactic acid bacteria have been used since ancient times for food preparation and for bio-conservation by fermentation. Selected strains are capable of producing antimicrobial peptides - bacteriocins, which can be natural preservatives, especially in products with short shelf lives. The present study is focused on inhibitory effects of the bacteriocin-producing bacteria strains Enterococcus faecium, Pediococccus acidilactici and Lactobacillus plantarum against Listeria innocua as an indicator microorganism. Freeze-dried preparations of bacterial strains producing particular bacteriocins were tested by agar well-diffusion assay and by the traditional spread plate method. Plantaricin exhibited the highest anti-listerial effect among the tested bacteriocins. Pediocin also demonstrated a distinct inhibitory effect, but enterocin appeared to be heat labile and its efficiency was also suppressed under cold storage conditions. Plantaricin reduced Listeria innocua counts by 1 log in dairy spread made from cheese and quark. The formation of bacteriocins by various Lactobacillus plantarum strains were substantially influenced by the cultivation conditions of the mother culture and by the microbial preparation process before freeze-drying. Bacteriocins introduced into foodstuffs via protective cultures in situ offer new perspectives on enhancing food quality and safety.Bakterije mliječne kiseline od davnina se koriste u proizvodnji hrane te za biološko konzerviranje putem vrenja. Odabrani sojevi bakterija mliječne kiseline mogu sintetizirati bakteriocine - peptide s antimikrobnim djelovanjem, a koji se mogu koristiti kao prirodni konzervansi i to prije svega za proizvode kratkog roka trajanja. Svrha ovog istraživanja bila je ispitati inhibitiorne učinke sojeva Enterococcus faecium, Pediococccus acidilactici i Lactobacillus plantarum koji sintetiziraju bakteriocine naspram soja Listeria innocua kao testnog mikroorganizma. Dubokosmrznuti pripravci bakterijskih sojeva koji sintetiziraju specifične bakteriocine ispitivani su dvama metodama - metodom ubrizgavanja kulture u rupice na testnom agaru i klasičnim nacjepljivanjem na hranjivu podlogu. Među svim ispitivanim bakteriocinima plantaricin je pokazao najjači inhbitorni učinak naspram testnog soja Listeria innouca. Pediocin je također pokazao određeni inhibitorni učinak, dok se enterocin pokazao termolabilnim te se njegov učinak znatno smanjio u uvjetima hladnog čuvanja. U uzorcima namaza na bazi sira i kvarka plantaricin je uzrokovao redukciju broja živih stanica soja Listeria innocua za 1 log. Na sposobnost proizvodnje bakteriocina u različitih sojeva vrste Lactobacillus plantarum snažno su utjecali uvjeti uzgoja izvorne kulture kao i primijenjeni procesi pripreme prije postupka dubokog smrzavanja. Bakteriocini koji se namirnicama dodaju in situ putem zaštitnih kultura predstavljaju nove mogućnosti za poboljšanje kvalitete i sigurnosti prehrambenih proizvoda

EXPERIMENTAL STUDY OF DAMAGED CR-COATED FUEL CLADDING IN POST-ACCIDENT CONDITIONS

To enhance the safety of nuclear power, the focus of researchers all around the world has recently mainly objected on the development of Accident Tolerant Fuels. Especially the Chromium coating of current Zirconium based cladding has been widely suggested and discussed for its immense positive effect on overall cladding properties. Nevertheless, it was observed that during the first stage of the Loss of Coolant Accident, cracks appear in the Cr coating due to its inability to tolerate higher plastic strain. Therefore, experimental methodology used in this article focuses on testing fuel cladding with damaged Cr coating after the high-temperature transient. The impact of cracks on degradation of cladding mechanical properties was observed using optical microscopy, ring compression test, microhardness, and evaluating hydrogen content and weight gain

THE EFFECT OF EXOGENOUS PROTEASE IN BROILER DIETS ON THE APPARENT ILEAL DIGESTIBILITY OF AMINO ACIDS AND ON PROTEASE ACTIVITY IN JEJUNUM

Abstract The objective of this study was to evaluate the effect of a mono-component commercial serine protease supplement in broiler diets on apparent ileal amino acid digestibility and protease activity. A total of 150 male (28 d old) ROSS 308 were randomly placed into 30 battery pens and divided into 5 treatment groups with 6 replicates each. The experiment was performed for 7 days. Five dietary treatments were used: 2 standard protein diets without (SP) and with protease (SP + P) formulated 20.7 % CP, 2 lower-protein diets (19.9 % CP) without (LP) and with protease (LP + P) and one lower-protein diet with protease and with doubled rapeseed meal (RSM) content (SP-RSM + P) compared with the other treatments. Lower-protein diets were formulated with a 4 % decrease in the relative CP value compared with the standard protein diet. Enzyme protease was added to the diets at a concentration of 200 ppm (15,000 PROT units per kg). The diets contained 0.3 % Cr2O3 to facilitate the estimation of apparent AA digestibility and overall apparent ileal crude protein digestibility. Mono-component protease had no effect on apparent ileal AA digestibility or jejunum protease activity if diets contained the same level of RSM. The supplement of exogenous protease did not affect (P > 0.05) the apparent ileal AA digestibility coefficients if a higher RSM level was used. The CP level influenced (P < 0.05) only the coefficients of the apparent ileal AA digestibility of Pro and Arg. The RSM level (P < 0.01) had significant effects on protease activity in the jejunum

Thin film systems

This bachelor’s thesis is focused on the problematics of thin-film technology. In the beginning the work deals with a general theory of this problematics, discusses various methods and ways to lay a thin film, where more emphasis is placed on magnetron sputtering, which is used in the practical part of the work, and describes procedures that are performed before and after the application of the thin film. The magnetron sputtering coating machine NP-12 and its control are described in the practical part of the work. Subsequently the selection and adjustment of suitable substrates is made, the thin-film system is deposited using the magnetron sputtering method and the analysis of the properties of deposited thin-film samples is done

Thin film systems

Tato bakalářská práce je zaměřena na problematiku technologie vytváření tenkých vrstev. V úvodu se zabývá obecnou teorií této problematiky, rozebírá různé metody a způsoby nanášení tenkých vrstev, kdy je kladen větší důraz na metodu magnetronového naprašování, která je využita v experimentální části práce, a popisuje procedury, které jsou prováděny před a po samotném nanesením tenké vrstvy. V praktické části práce je popsáno magnetronové naprašovací zařízení NP-12 a jeho ovládání. Následně je proveden výběr a úprava vhodných substrátů, depozice tenkovrstvého systému pomocí magnetronového naprašování a analýza vlastností deponovaných tenkovrstvých vzorků.This bachelor’s thesis is focused on the problematics of thin-film technology. In the beginning the work deals with a general theory of this problematics, discusses various methods and ways to lay a thin film, where more emphasis is placed on magnetron sputtering, which is used in the practical part of the work, and describes procedures that are performed before and after the application of the thin film. The magnetron sputtering coating machine NP-12 and its control are described in the practical part of the work. Subsequently the selection and adjustment of suitable substrates is made, the thin-film system is deposited using the magnetron sputtering method and the analysis of the properties of deposited thin-film samples is done.

Možnosti snížení obsahu dusíkatých látek v krmných směsích pro brojlerová kuřata

The aim of the dissertation was to investigate the effect of exogenous protease (EP) in feed mixtures (FM) for broiler chickens with reduced crude protein (CP) content by 4 and 8 % on growth parameters, carcass quality, apparent ileal digestibility of amino acids and protease activity in the jejunum of broiler chickens. At the same time, the effect of EP on the given parameters was investigated at the increased level of rape seed meal (RSM) in FM. The addition of EP to KS with a 4% reduction in CP did not have a statistically significant (P> 0,05) effect on growth, conversion and feed intake, quality of carcass, nor on the apparent ileal digestibility of amino acids and protease activity in jejunum of the broiler chicken. Higher content of RSM in FM with a 4% CP reduction negatively (P 0.05) effect on protease activity in the jejunum of broilers with FM intake with an 8% CP reduction. Higher content of RSM in FM with an 8% CP reduction significantly decreased (P <0.05) apparent ileal digestibility of Pro and significanlty (P <0.05) increased protease activity in broilers jejunum

Wireless charger based on the NFC Forum WLC 2.0 standard

This diploma thesis is focused on wireless charging technology according to the Wireless Charing 2.0 standard by the NFC Forum and the design of an ASIC circuit of a device functioning as a listener, where the primary emphasis is placed on the digital design of this circuit. In the beginning the work deals with a general theory, gradually discussing all the standards from the NFC Forum that are necessary for the control protocol design according to the Wireless Charging 2.0. Subsequently, the analysis of a real communication in the development kit for this standard is conducted, based on which the system design of the digital circuit is made. The designed circuit is described by VHDL language and verified by running the basic simulations to check the functionality of the designed parts of the circuit. In the final part of the thesis, a prototype module with the proposed system is fabricated, implemented in an FPGA with a connected battery charger circuit and its functionality is tested in practice