9 research outputs found
A comparative analysis of milling strategies of complex geometry surfaces
This paper analyses the influence of machining strategies and cutting parameters on the milling of aluminium complex geometry parts. In the first experimental phase, parts were machined with a combination of two roughing strategies and three finishing strategies, with recommended machining parameters. The machining time, machining surface roughness, and the surface geometric accuracy were measured. In the second phase, a new sample was machined with corrected cutting parameters using the best strategy adopted from the first phase. The results have shown that the selection of machining strategy and cutting parameters significantly affects the productivity, quality, and accuracy when machining complex geometry parts
Apical Leakage after Four Endodontic Instrumentation and Filling Procedures
Svrha je bila ispitati apeksnu propusnost punjenih korijenskih kanala uporabom konstrukcije za prijenos tekuÄine, nakon dvije razliÄite tehnike instrumentacije (ādouble flareā i step-backā) kombinirane s uporabom dvaju razliÄitih materijala za punjenje (eukaperka i Roeko
sealĀ®).
U pokusu je rabljen uzorak od 40 trajnih jednokorijenskih zuba. Zubi su dekoronirani na razini caklinskocementnog spojiÅ”ta, a zatim podijeljeni u Äetiri skupine od po 10 zuba. Korijenski kanali prve i druge skupine mehaniÄki su obraÄeni ādouble flareā tehnikom, a āstepbackā tehnika primijenjena je u treÄoj i Äetvrtoj skupini.
kanali su tijekom instrumentacije ispirani 2,5% otopinom NaOCl. ObraÄeni korijenski kanali prve i treÄe skupine punjeni su gutaperka kolÄiÄima i eukaperka pastom tehnikom hladne alteralne kondenzacije, dok je u drugoj i Äetvrtoj skupini rabljen Roeko sealĀ® umjesto eukaperke tijekom punjenja. UÄinjenim endodontskim postupcima stvorene su Äetiri skupine: skupina DF/EF (double-flare
/ eukaperka) skupina DF/RS (double-flare / Roeko sealĀ®) skupina, skupina SB/EP (step back/eukaperka) i skupina SB/RS (step back / Roeko sealĀ®). Punjeni korijeni pohranjeni su u sterilnu fizioloÅ”ku otopinu na 37Ā°C u razdoblju od 7 dana nakon Äega su postavljeni u konstrukciju za prijenos tekuÄine. Propusnost je mjerena pomakom zraÄnoga mjehuriÄa u kapilarnoj cijevi spojenoj s apeksnim krajem
napunjenoga zubnog korijena.
Razlika izmeÄu skupine DF/EF (0,152 Ī¼L Ā± 0,12), skupine DF/RS (0,186 Ī¼L Ā± 0,098), skupine SB/EP (0,195 Ī¼L Ā± 0,12), i skupine SB/RS (0,360 Ī¼L Ā± 0,230) statistiÄki je analizirana Sheffe (ANOVA) testom. statistiÄki znatna razlika utvrÄena je izmeÄu skupine DF/EP i skupine SB/RS. Daljnjom statistiÄkom raÅ”Älambom s pomoÄu Mann-Whitney U testa utvrÄeno je da razliÄita tehnika instrumentacije utjeÄe na rezultate raÅ”Älambe.
U uvjetima pokusa, rezultati dobiveni primjenom konstrukcije za prijenos tekuÄine pokazuju da razliÄiti materijali za punjenje korijenskih kanala ne utjeÄu na apeksnu propusnost.The aim of this research was to examine apical obturation leakage of filled root canals by a fluid transport model after two different instrumentation techniques (ādouble flareā and āstep-backā) combined with use of two different sealers (eucapercha and Roeko sealĀ®).
A sample of 40 permanent single-rooted teeth was used. The coronal part of each tooth was removed at the amelo-cement junction. Teeth were divided into four groups of 10 teeth each. Root-canals of the first and second group were cleaned and shaped by ādouble flareā technique while āstep-backā technique was performed in the third and fourth group. All root-canals were irrigated with 2.5% NaOCl during instrumentation. Prepared root-canals of the first and third group were filled with gutta-percha points and eucapercha sealer by the cold lateral condensation technique while in the second and fourth group Roeko sealĀ® was used as a sealer instead of eucapercha
during filling procedure. Filled roots were stored in NaCl 3% at 37Ā°C for 7 days. These procedures formed four groups: group DF/EO (double flare/eucapercha), group DF/RS (double flare/Roeko sealĀ®, group SB/EP (step back/eucapercha) and group SB/RS (step back/Roeko sealĀ®). Each root was mounted in a fluid transport model
and leakage was measured by the movement of an air bubble in a capillary glass tube connected to the experimental root section.
The difference between group DF/EP (0,152 Ī¼L Ā± 0,12), group DF/RS (0,186 Ī¼L Ā± 0,098), group SB/EP (0,195 Ī¼L Ā± 0,12), and group SB/RS (0,360 Ī¼L Ā± 0,230) was statistically analyzed by Sheffe test. Statiatically significant difference was determined between group DF/EO and group SB/RS. Further statistical anlysis peformed by
Mann-Whitney U test showed that different instrumentation technique were responsable for the results of analysis.
Under the conditions of this research, results obtained with fluid transport model indicate that there is no statistically significant difference between groups where rootcanals were filled with different materials. Apical leakage was signifuicantly lower where root-canals were instrumented by ādouble flareā technique
NEW FEED ADDITIVES BASED ON PHYTOGENICS AND ACIDIFIERS IN ANIMAL NUTRITION **
Abstract: Low regulations for feed additives use, has been changed in EU as well as in our country, especially in use of antibiotics as growth promotors. Along years it has investigated an alternative for antibiotics as growth promotors. Essential oilsand organic acids are one of alternative feed, which acting in a few of the most important directions: as antioxidants, metabolic upgraders, growth promotors and development of pathogenic microorganizms controllers, including moulds and bacterias and as environmental protecting through control of amonia and nitrogen excretion. The objective of this paper was to determine the composition of essential oils in a commercial product which, in combination with the blend of organic acids may be used in poultry nutrition as an alternative to antibiotic growth promoters and establish impacts on performance parameters in broilers and microbiological properties of feces. Obtained results showed that the product contained an essential oil in which over 75 % of total mass account for 2-phenol- carvacrol and eugenol
Optimization of co-solvent addition in supercritical fluid extraction of fat with carbon dioxide
This investigation is concerned with supercritical fluid extraction (SFE) using CO2, as an analytical technique for total fat extraction from food and feed samples. Its most significant advantages are safety, cleanness, and shorter extraction time. The main limitation of this technique includes the difficulty of extracting polar lipids due to the non-polar character of the solvent (CO2) used for the extraction. The influence of ethanol as a co-solvent on the SFE of mash pig feed was investigated in this paper. Total fat content was determined by SFE and Soxhlet method for ten commercially available mesh pig feeds. Yields of the fat extracted by both methods were plotted one against the other and compared. Statistically significant difference (p ā¤ 0.05) has been found only between the total fat obtained by the Soxhlet extraction and SFE by pure CO2. Based on the mathematical model, maximum yield of the extracted fat is achieved at an ethanol addition of 0.67 ml/g of sample, when the other parameters are the same as recommended by the producerās procedure
EFFECT OF Artemisia absinthium ESSENTIAL OIL ON ANTIOXIDATIVE SYSTEMS OF BROILER'S LIVER
ABSTRACT: The effect of Artemisia absinthium essential oil (AAEO) on enzymatic activity of superoxide-dismutase (SOD), glutathione-peroxidase (GSHPx), glutathione-reductase (GR), peroxidase (POD), xantine-oxidase (XOD) and non-enzymatic (content of lipid peroxides (LPx) and gluthathione (GSH)) antioxidative status of broilers infected with mixture of oocysts of Eimeria tenella, Eimeria mitis and Eimeria necatrix in comparison to coccidiostat salinomycin was investigated. The in vivo investigation were carried out on 120 Arbor acres broilers of both sexes. Broilers were randomly distributed into four groups. Group A was uninfected and untreated; group B was infected and was kept untreated; group C preventively received coccidiostatic salinomycin in quantity of 60 mg/kg of feed and was inoculated with coccidia species at 21 st day-of-age and group D received in feed AAEO in quantity of 3 g/kg and was infected with Eimeria oocysts at 21 st day-of-age. Livers were collected for the subsequent evaluation of antioxidative status. It was concluded that AAEO added in feed for broilers prevented the development of coccidia oocysts and therefore it can be used as prophylactic feed additive
Connection of inherent structure with nutrient profiles and bioavailability of different co-products and by-products after processing using advanced grading and vibrational molecular spectroscopy
From Agricultural Waste to Biofuel: Enzymatic Potential of a Bacterial Isolate Streptomyces fulvissimus CKS7 for Bioethanol Production
Purpose To avoid a negative environmental and economic impact of agricultural wastes, and following the principles of circular economy, the reuse of agricultural wastes is necessary. For this purpose, isolation of novel microorganisms with potential biotechnological application is recommended. The current researches in bioethanol production are aimed to reduce the production costs using low-cost substrates and in-house produced enzymes by novel isolated microorganisms. In line with this, in this study valorization of these agricultural by-products by novel isolate S. fulvissimus CKS7 to biotechnological value added products was done. Methods Standard microbiological methods were used for the isolation and characterization of strain. Enzymes activities were determinated using DNS method while, the ethanol concentration was determined based on the density of the alcohol distillate at 20 degrees C. Results The maximal enzymatic activities for amylase, cellulases (carboxymethyl cellulase and Avicelase), pectinase and xylanase were achieved using rye bran as a waste substrate for CKS7 growth. Obtained crude bacterial enzymes were used for enzymatic hydrolysis of lignocellulosic materials including horsetail waste, yellow gentian waste, corn stover, cotton material and corona pre-treated cotton material. The maximum yield of reducing sugars was obtained on horsetail waste and corona pre-treated cotton material. Waste brewer's yeast Saccharomyces cerevisiae was successfully used for the production of bioethanol using horsetail waste hydrolysate and corona pre-treated cotton material hydrolysate. Conclusion The obtained results showed that bacterial strain CKS7 has a significant, still unexplored enzymatic potential that could be used to achieve a cleaner, environmental friendly and economically acceptable biofuel production. [GRAPHICS]