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Isolation and analysis of multiply glycosylated desulfoglucosinolates from selected pland species of the Brassicaceae and Moringaceae families : diploma thesis
No full textU ovom radu analizirani su glukozinolati u biljnim vrstama Hesperis laciniata, Thlaspi perfoliatum (Brassicaceae) i Moringa oleifera (Moringaceae). Glavni cilj bio je izolacija i identifilacija desulfoglukozinolata iz različitih biljnih dijelova primjenom modificirane ISO 9167-1 metode te njihova kvalitativna i kvantitativna analiza korištenjem UHPLC-DAD-MS/MS sustava. Identificirano je ukupno 7 različitih desulfoglukozinolata, uključujući nekoliko do sada nepoznatih spojeva. Najveća koncentracija glukozinolata u H. laciniata utvrĎena je u cvijetu (110,08 µmol/g suhog biljnog materijala), dok je kod T. perfoliatum koncentracija bila najviša u komuščici (97,6 µmol/g). Kod sjemenki M. oleifera, dominantni spoj bio je glukomoringin (221,74 µmol/g). U biljci H. laciniata, najzastupljeniji glukozinolat bio je 4´- O-β-D-apiofuranozilglukomatronalin (69,57 µmol/g suhog biljnog materijala), dok je kod T. perfoliatum dominantni spoj bio 4´-O-(β-D-apiofuranoziloksi)benzil-glukozinolat (53,86 µmol/g). Nadalje, provedena je uspješna izolacija pojedinih glukozinolata korištenjem HPLC-DAD sustava sa sakupljačem frakcija. Iz biljke T. perfoliatum izolirane su tri frakcije: desulfoglukosinalbin, desulfo-apiofuranozilglukomatronalin i desulfo-(apiofuranoziloksi)benzil-glukozinolat. Rezultati ukazuju na specifične razlike u profilu glukozinolata meĎu vrstama, a identificirani spojevi predstavljaju značajan doprinos razumijevanju kemijske raznolikosti unutar porodica Brassicaceae i Moringaceae. Posebno se ističe identifikacija višestruko glikoziliranih glukozinolata, što doprinosi daljnjoj karakterizaciji bioloških i kemijskih svojstava ovih biljaka.In this study glucosinolates from the plant species Hesperis laciniata, Thlaspi perfoliatum (Brassicaceae), and Moringa oleifera (Moringaceae) were analyzed. The main goal was the isolation and identification of desulfoglucosinolates from different plant parts using a modified ISO 9167-1 method, followed by their qualitative and quantitative analysis using the UHPLC-DAD-MS/MS system. A total of seven different desulfoglucosinolates were identified, including several previously unknown compounds. The highest concentration of glucosinolates in H. laciniata was found in the flowers (110.08 µmol/g dry plant material), while in T. perfoliatum, the highest concentration was observed in the siliques (97.6 µmol/g). In the seeds of M. oleifera, the dominant compound was glucomoringin (221.74 µmol/g). In H. laciniata, the most abundant glucosinolate was 4´-O-β-D-apiofuranosylglucomatronalin (69.57 µmol/g dry plant material), whereas in T. perfoliatum, the dominant compound was 4´-O-(β-D- apiofuranosyloxy)benzyl-glucosinolate (53.86 µmol/g). Furthermore, successful isolation of individual glucosinolates was achieved using the HPLC-DAD system with a fraction collector. From T. perfoliatum, three fractions were isolated: desulfoglucosinalbin, desulfo-apiofuranosylglucomatronalin, and desulfo- (apiofuranosyloxy)benzyl-glucosinolate. The results highlight specific differences in glucosinolate profiles among the species studied, and the identified compounds represent a significant contribution to understanding the chemical diversity within the Brassicaceae and Moringaceae families. Notably, the identification of multiply glycosylated glucosinolates advances the characterization of the biological and chemical properties of these plants
Investigation of the corrosion behaviour of Ti and Ti6Al4V alloy in brackish water, seawater and seawater bittern : diploma thesis
No full textTi i Ti6Al4V legura imaju značajnu primjenu u medicini za izradu implantata, kao i za izradu dijelova konstrukcija kod koje se traže dobra mehanička svojstva, mala masa i visoka korozijska otpornost, što je bila i motivacija kod izbora materijala za istraživanje. U radu je provedeno ispitivanje korozijskog ponašanja Ti i Ti6Al4V legure u boćatoj, morskoj i gorkoj morskoj vodi. Elektrokemijska ispitivanja su obuhvaćala mjerenje potencijala otvorenog strujnog kruga (E OC ), kao i primjenu polarizacijskih metoda (linearne i potenciodinamičke polarizacije). Ti i Ti6Al4V legura pokazuju najpozitivniji potencijal u boćatoj vodi, a najnegativniji u gorkoj vodi. Najmanja vrijednost korozijske struje i najveća vrijednost polarizacijskog otpora dobiveni su mjerenjem u boćatoj vodi za Ti, dok je Ti6Al4V pokazala najmanju korozijsku otpornost u gorkoj vodi. Analiza površine elektroda nakon polarizacijskih mjerenja optičkom mirkoskopijom, optičkom profilometrijom i SEM/EDS ispitivanjima pokazala je mala oštećenja što ukazuje na visoku korozijsku otpornost Ti i Ti6Al4V legure u ispitivanim medijima.Ti and Ti6Al4V alloys have significant applications in medicine for the manufacture of implants, as well as for the manufacture of structural parts that require good mechanical properties, low weight and high corrosion resistance, which was the motivation for selecting these materials for research. In this work, the corrosion behavior of Ti and Ti6Al4V alloy in brackish, sea and bitter sea water was tested. Electrochemical investigations included the measurement of the open circuit potential (E OC ), as well as the application of polarization methods (linear and potentiodynamic polarization). Ti and Ti6Al4V alloy show the most positive potential in brackish water and the most negative in bitter water. The lowest value of corrosion current and the highest value of polarization resistance were obtained by measuring in brackish water for Ti, while Ti6Al4V showed the lowest corrosion resistance in bitter water. The analysis of the electrode surface after polarization measurements by optical microscopy, optical profilometry and SEM/EDS tests showed small damages, which indicates the high corrosion resistance of Ti and Ti6Al4V alloy in the tested media
Investigation of the corrosion behaviour of stainless steels in seawater of varying salinity : diploma thesis
No full textU radu je ispitano korozijsko ponašanje nehrđajućih čelika AISI 304L, AISI 316L i 2205 DSS u morskoj vodi različitog saliniteta – boćatoj (BMV), morskoj (MV) i ugušćenoj morskoj vodi (UMV) koja je uzeta iz procesa proizvodnje soli (solane) nakon kristalizacije natrijeva klorida i sadrži nižu koncentraciju Na + i Cl⁻ iona. Ispitivanje je izvršeno primjenom elektrokemijskih metoda (potencijal otvorenog strujnog kruga (E OC ), linearna i potenciodinamička polarizacija) te analizom površine (optička mikroskopija, SEM/EDS, optička profilometrija). Dobiveni rezultati pokazuju da u svim otopinama otpornost na koroziju raste sljedećim redoslijedom: AISI 304L < AISI 316L < 2205 DSS, što se pripisuje sve većem udjelu legirajućih elemenata poput kroma i molibdena koji stabiliziraju pasivni oksidni sloj i povećavaju otpornost na lokalnu (pitting) koroziju. Dupleks čelik 2205 DSS pokazao je najpozitivnije vrijednosti E OC i korozijskog (E kor ) potencijala, najveći polarizacijski otpor (R p ), najnižu korozijsku struju (i kor ), najpozitivniji pitting potencijal (E dp ) te najšire pasivno područje, što ukazuje na njegovu superiornu stabilnost u svim ispitivanim medijima. Posebno je zanimljivo da je u UMV, iako s višim ukupnim salinitetom, otpornost na koroziju bila veća nego u običnoj MV, što se objašnjava smanjenom koncentracijom Cl - iona i prisutnošću Mg²⁺, Ca²⁺ i SO₄²⁻ koji potiču formiranje zaštitnih taloga na površini čelika. Površinske analize potvrdile su izraženu rupičastu koroziju kod AISI 304L u MV, dok su u BMV i UMV oštećenja bila značajno manja, osobito kod 2205 DSS koji je u većini uvjeta ostao gotovo neoštećen. Rezultati jasno upućuju na potrebu odabira čelika otpornijih na lokalnu koroziju za primjenu u morskim okruženjima, pri čemu se 2205 DSS pokazao kao najsigurniji izbor.This study investigated the corrosion behaviour of stainless steels AISI 304L, AISI 316L and 2205 DSS in seawater with different salinity – brackish water (BMV), seawater (MV) and concentrated seawater (UMV) which is taken from the salt production process after NaCl crystallization and contains lower concentration of Na + and Cl - ions. The study was carried out using electrochemical methods (open circuit potential (E OC ), linear and potentiodynamic polarization) and surface analysis techniques (optical microscopy, SEM/EDS, optical profilometry). The results showed that corrosion resistance increased in all tested solutions in the following order: AISI 304L < AISI 316L < 2205 DSS, which is due to the increasing content of alloying elements such as chromium and molybdenum, which stabilize the passive oxide layer and increase the resistance to localized (pitting) corrosion. Duplex steel 2205 DSS exhibited the most positive E OC and corrosion potential (E corr ) values, the highest polarization resistance (R p ), the lowest corrosion current density (i corr ), the most positive pitting potential (E dp ) and the widest passive range, indicating its superior stability in all tested environments. Remarkably, – despite the higher total salt content, corrosion resistance in concentrated seawater was greater than in seawater, which can be explained by the lower concentration of Cl - ions and the presence of Mg²⁺, Ca²⁺ and SO₄²⁻ ions, which promote the formation of protective surface deposits on the steel. Surface analysis confirmed pronounced pitting corrosion in AISI 304L in seawater, while damage was significantly less in brackish and concentrated seawater, especially in 2205 DSS, which remained virtually undamaged under most conditions. These results clearly show the importance of selecting steels with higher resistance to localized corrosion for marine applications, with 2205 DSS proving to be the most reliable choice
Mechanical recycling of the trimmer line : diploma thesis
No full textU ovom radu ispitan je utjecaj mehaničkog recikliranja na strukturu i toplinsku postojanost materijala od kojeg su izrađene niti za košnju. Niti za košnju su mehanički reciklirane u laboratorijskom dvopužnom ekstruderu. Infracrvena spektroskopija s Fourierovom transformacijom (FT-IR) upotrijebljena je za identifikaciju polimernog materijala od kojeg su izrađene niti te za određivanje strukture materijala nakon recikliranja. Usporedbom snimljenih FT-IR spektrograma s podatcima u literaturi i bazi podataka utvrđeno je da je poliamid 6 (poli( -kaprolaktam)) polimer od kojeg su izrađene niti za košnju. Također je utvrđeno da mehaničko recikliranje nije utjecalo na strukturu niti za košnju. Utjecaj mehaničkog recikliranja na toplinsku postojanost niti za košnju istraživan je primjenom termogravimetrijske analize (TG). Zaključeno je da mehaničko recikliranje neznatno poboljšava toplinsku postojanost materijala od kojeg su izrađene niti za košnju.In this paper, influence of mechanical recycling on the structure and thermal stability of the material from which the trimmer lines were made was examined. Trimmer lines were mechanically recycled in a laboratory twin screw extruder. Fourier transform infrared spectroscopy (FT-IR) was used to identify the polymer material from which the lines were made and to determine the structure of the material after recycling. By comparing the recorded FT-IR spectrograms with the data in the literature and the database, it was determined that polyamide 6 (poly( -caprolactam)) is the polymer from which the trimmer lines were made. It was also found that mechanical recycling did not affect the structure of the trimmer lines. The influence of mechanical recycling on the thermal stability of trimmer lines was investigated using thermogravimetric analysis (TG). It was concluded that mechanical recycling slightly improves the thermal stability of the material from which the trimmer lines were made
SELECTION OF OPTIMAL PRECIPITATING AGENT FOR ZINC REMOVAL FROM AQUEOUS SOLUTIONS BY CHEMICAL PRECIPITATION : bachelor thesis
No full textIndustrijskom revolucijom započelo je intenzivnije onečišćenje okoliša različitim štetnim tvarima. Značajnu ulogu u onečišćenju prirodnih voda imaju industrijske otpadne vode, koje su jedan od glavnih izvora emisije teških metala u okoliš. S ekološkog i zdravstvenog stajališta važno je prije emisije industrijske otpadne vode adekvatno pročistiti. Najčešće metode obrade takvih voda su kemijsko taloženje, ionska izmjena, adsorpcija i membranske tehnike. U ovome radu provedeno je uklanjanje cinka iz vodenih otopina koncentracija 100 mg/L i 500 mg/L metodom kemijskog taloženja uz prethodnu neutralizaciju do pH područja 7,0-7,5; 8,0-8,5 i 9,0-9,5 različitim taložnim sredstvima - suspenzijama vapnenog mlijeka pripravljenim iz tehničkog vapna različite čistoće te natrijevim hidroksidom. Uklanjanje cinka uspješno je provedeno uz neutralizaciju u pH području 9,0-9,5 korištenjem svih ispitanih taložnih sredstava, s ostatnom koncentracijom cinka ispod maksimalno dopuštene. Uzimajući u obzir učinkovitost taložnog sredstva, cijenu te količinu nastalog otpadnog mulja, optimalno taložno sredstvo za ispitane eksperimentalne uvjete je suspenzija vapnenog mlijeka pripravljena iz tehničkog vapna čistoće 94,3%.With the industrial revolution, more intensive environment pollution with various harmful substances began. Industrial wastewaters, as one of the main sources of heavy metal emissions into the environment, play a significant role in the pollution of natural waters. From an ecological and health point of view, it is important to adequately purify industrial wastewaters before emission. The most common methods of their treatment are chemical precipitation, ion exchange, adsorption and membrane techniques. In this bachelor thesis, the removal of zinc from aqueous solutions containing 100 mg Zn/L and 500 mg Zn/L was carried out by chemical precipitation with prior neutralization to a pH ranges of 7.0-7.5; 8.0-8.5 and 9.0-9.5, respectively, using different precipitating agents - milk of lime prepared from technical lime of different purity and sodium hydroxide. Zinc removal was successfully performed with neutralization in the pH range of 9.0-9.5 using all precipitating agents tested, with the residual zinc concentration below the maximum allowed. Taking into account the effectiveness of the precipitating agent, costs and the amount of waste sludge generated, the optimal precipitating agent for the tested experimental conditions is milk of lime prepared from the technical lime with 94.3% of purity
Bacterial resistance to antibiotics in Klebsiella and Enterobacter isolates from wastewater treatment plants in Croatia
No full textCilj ovog diplomskog rada je izolirati karbapenem-rezistentne Klebsiella i Enterobacter izolate iz uzoraka otpadne vode iz uređaja za otpadne vode (UPOV-i) grada Splita i morske vode u blizini pripadajućih podmorskih ispusta u srednjem Jadranu, te testirati njihovu fenotipsku osjetljivost na antibiotike. Određena je razina fekalnog onečišćenja u uzorcima te je 108 izolata identificirano do vrste i ispitana njihova fenotipska osjetljivost na 16 antibiotika metodom disk-difuzije na Mueller-Hinton agaru. Najveći broj izolata pokazao je rezistenciju na cefoksitin (97,22%), piperacilin (90,74%), aztreonam (84,26%) i meropenem (79,63%), dok je najmanja učestalost rezistencije zabilježena na trimetoprim-sulfametoksazol (17,59%). Rezultati pokazuju visok postotak rezistencije na različite klase antibiotika, odnosno višestruko rezistentni fenotip izolata i moguću prisutnost karbapenemaza. Također, obzirom da UPOV Katalinića Brig obrađuje i otpadne vode iz KBC-a Split, mogući su rizici širenja bolničkih rezistentnih sojeva u morski okoliš, što potvrđuje potrebu za daljnjim praćenjem njihove učestalosti te nastavkom istraživanja u smjeru određivanja genotipa rezistencije ovih oportunističkih patogena kritičnog prioriteta.The aim of this thesis was to isolate carbapenem-resistant Klebsiella and Enterobacter isolates from wastewater samples from wastewater treatment plants (WWTPs) of the city of Split and seawater from the adjacent submarine outlets in the central Adriatic, and to test their phenotypic sensitivity to antibiotics. The level of fecal contamination in the samples was determined, and 108 isolates were identified to species and their phenotypic sensitivity to 16 antibiotics was tested using the disk-diffusion method on Mueller-Hinton agar. The largest number of isolates showed resistance to cefoxitin (97.22%), piperacillin (90.74%), aztreonam (84.26%) and meropenem (79.63%), while the lowest frequency of resistance was recorded against trimethoprim-sulfamethoxazole (17.59%). The results show a high percentage of resistance to different classes of antibiotics, i.e. the multiple resistant phenotype of the isolates and the possible presence of carbapenemases. Also, considering that UPOV Katalinića Brig also processes wastewater from University Hospital Split, there are possible risks of the spread of hospital resistant strains into the marine environment, which confirms the need for further monitoring of their frequency and the continuation of research in the direction of determining the resistance genotype of these WHO critical-priority opportunistic pathogens
Evaluation of the rosemery extract effect on the thermal properties of polyethylene oxide based composite material : diploma thesis
No full textPoli(etilen-oksid) (PEO) je vodotopljiv, netoksičan i biokompatibilan polimer s velikim potencijalnom primjene u mnogim granama industrijama. Kako bi mu se proširila primjena, neka svojstva je potrebno poboljšati dodavanjem aditiva. Dodatak prirodnih aditiva, poput ekstrakta ružmarina (ER), predstavlja strategiju za poboljšanje strukturnih, toplinskih, mehaničkih i biorazgradljivih svojstava. Cilj ovog rada je pripremiti kompozite PEO/ER ekstruzijom, istražiti utjecaj dodatka ER na strukturu PEO primjenom infracrvene spektroskopije sa Fourierovom transformacijom, zaključiti o utjecaju dodatka ER na toplinska svojstva PEO pomoću diferencijalne pretražne kalorimetrije (DSC) i temeljem termogravimetrijske analize (TGA) zaključiti o utjecaju dodatka ER na toplinsku postojanost PEO. Ovakvo istraživanje omogućava dublje razumijevanje utjecaja ER na svojstva PEO, što je ključno za razvoj novih materijala s unaprijeđenim svojstvima.Poly(ethylene-oxide) (PEO) is water-soluble, non-toxic and biocompatible polymer with great potential for various industries. In order to expand its application, some properties needs to be enhanced by adding additives. Adding natural additives such as rosemary extract (ER), represents a strategy for improving structural, thermal, mechanical and biodegradable properties. The aim of this study is to prepare PEO/ER composite by hot-melt extrusion, investigate the influence of ER addition on the structure of PEO using Fourier-transform infrared spectroscopy (FTIR), conclude about the effect of ER addition on thermal properties of PEO using differential scanning spectroscopy (DSC) and based on thermogravimetric analysis (TGA) estimate the effect of ER addition on thermal stability of PEO. This research enables a deeper understanding of the impact of ER on PEO properties, which is crucial for the devolopment of new materials with improved properties
Spectroscopic determination of glucosinolates in plants Sinapis alba and Lepidium draba : diploma thesis
No full textU ovom radu UHPLC-DAD-MS/MS analizom odreĎen je glukozinolatni profil različitih biljnih dijelova biljke Lepidium draba i nepoznatog biljnog uzorka te glukozinolatni profil sjemenki biljke Sinapis alba. Glukozinolati su iz uzoraka izolirani u desulfatiranome obliku modificiranom metodom ISO 9167-1. Dobiveni glukozinolatni profil biljke Lepidium draba usporeĎen je s glukozinolatnim profilom nepoznate biljne vrste kako bi se odredile kemotaksonomske značajke nepoznatog biljnog uzorka. U oba uzorka, najveći udio glukozinolata je pronaĎen u listu, a najmanji u stabljici. Pri tome, najzastupljeniji spoj u listu oba uzorka je glukorafanin (41,49 ± 4,05 μmol/g suhog biljnog materijala biljke Lepidium draba te 40,40 ± 3,62 μmol/g suhog biljnog materijala nepoznatog uzorka), a u cvatu pak glukosinalbin (32,03 ± 5,43 μmol/g u biljci Lepidium draba te 34,73 ± 0,76 μmol/g u nepoznatom uzorku). Najzastupljeniji glukozinolati u oba uzorka potječu od metionina. Na temelju znatne sličnosti glukozinolatnih profila uzoraka te UV i MS2 spektara, zaključeno je da nepoznatni uzorak vjerojatno pripada vrsti Lepidium draba. Obzirom da je glukozinolatni profil sjemenki biljke Sinapis alba bio uvelike jednostavniji od gore navedenih uzoraka, taj uzorak je posluţio za potvrdu strukture najzastupljenijeg spoja sjemenki - desulfoglukosinalbina. Struktura je potvrĎena NMR tehnikom te je utvrĎena β konfiguracija anomernog ugljikovog atoma glukozne jedinice glukosinalbina.In this paper, UHPLC-DAD-MS/MS analysis was used for determination of the glucosinolate profile of various plant parts of Lepidium draba and an unknown plant sample, as well as the glucosinolate profile of Sinapis alba seeds. Glucosinolates were isolated from the samples in their desulfated form using a modified ISO 9167-1 method. The obtained glucosinolate profile of Lepidium draba was compared with the glucosinolate profile of the unknown plant species in order to determine chemotaxonomic characteristics of the unknown plant sample. In both samples, the highest glucosinolate content was found in the leaves, while the lowest content was found in the stem. The most abundant compound in the leaves of both samples was glucoraphanin (41.49 ± 4.05 μmol/g dry plant material of Lepidium draba and 40.40 ± 3.62 μmol/g dry plant material of the unknown sample) and glucosinalbin in the inflorescence (32.03 ± 5.43 μmol/g in Lepidium draba and 34.73 ± 0.76 μmol/g in the unknown sample). The most abundant glucosinolates in both samples are derived from methionine. Based on the significant similarity in the glucosinolate profiles and UV and MS2 spectra of the samples, it was concluded that the unknown sample likely belongs to the Lepidium draba species. Since the glucosinolate profile of Sinapis alba seeds was much simpler than that of the above-mentioned samples, this sample was used for confirmation of the structure of the most abundant compound in the seeds - desulfoglucosinalbin. The structure was confirmed using NMR techniques, and the β configuration of the anomeric carbon atom of the glucose unit of glucosinalbin was determined