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Testing of ion-selective membranes based on iron(II) sulphide with the addition of nanoparticles of magnitite to the response to iron cations : master thesis
No full textProvedeno je ispitivanje odziva ionsko-selektivnih membrana na željezove(II) i željezove(III) ione u otopinama željezovih soli pripravljenih u acetatnom ili dušičnom puferu u svrhu namještanja pH vrijednosti otopine. Osnovni cilj bilo je testirati membranske elektrode te ispitati mogućnost praktične primjene istih. S obzirom da su ionsko-selektivne membrane predstavljene u ovom radu modificirane nanočesticama magnetita, ispitan je i njihov utjecaj na karakteristike senzora kao što su linearno dinamičko područje odziva te osjetljivost metode. Testiranje svake membrane je ponovljeno minimalno tri puta. Potenciometrijska metoda se jako često koristi u laboratorijima zbog svoje jednostavnosti, niske cijene i praktičnosti. Selektivnost metode može se povećati promjenom reakcijskih uvjeta, odnosno s promjenom pH otopine uzorka. Ispitivanje membrana se vršilo u elektrokemijskoj ćeliji metodom slijednog razrjeđivanja koristeći otopinu željezova(II) sulfata heptahidrata pripremljenu u acetatnom puferu, odnosno otopinu željezova(III) nitrata nonahidrata pripremljenu u dušičnom puferu. Razrjeđivanje se provodilo sve dok razlika potencijala između dva mjerenja nije iznosila 0-1 mV. Dobivene vrijednosti odziva grafički su obrađene.The response of ion-selective membranes to iron(II) and iron(III)ions in solutions of iron salts prepared in acetate or nitrogen buffer was performed in order to adjust the pH value of the solution. The main goal was to test membrane electrodes and examine the possibility of their practical application. Since the ion-selective membranes presented in this paper were modified with magnetite nanoparticles, their influence on the sensor characteristics such as the linear dynamic response range and the sensitivity of the method was also examined. Testing of each membrane was repeated at least three times. The potentiometric method is very often used in laboratories due to its simplicity, low cost and practicality. The selectivity of the method can be increased by changing the reaction conditions such as by changing the pH of the sample solution. Membrane testing was performed in an electrochemical cell by sequential dilution using a solution of iron(II) sulfate heptahydrate prepared in acetate buffer, or a solution of iron(III) nitrate nonahydrate prepared in nitrogen buffer. Dilution was performed until the potential difference between the two measurements was 0-1 mV. The obtained response values were graphically processed
Cytotoxic activity of 3-aminophenylboronic acid and indomethacine : diploma thesis
No full textKemija borovih spojeva postaje sve veći predmet istraživanja zbog specifičnih svojstava bora i njegovih spojeva koji mogu imati primjenu u medicini i farmaciji. Boronične kiseline su kemijski spojevi koji sadrže trovalentni borov atom. Njihova blaga reaktivnost i stabilnost čine boronične kiseline atraktivnim sintetičkim međuproduktima. Borovi spojevi posjeduju značajna biološki aktivna svojstva koja mogu biti od iznimne koristi u liječenju mnogih bolesti. Spoj, 3-aminofenilboronična kiselina (3-APBA), postoji kao bijeli kristalični prah koji je topljiv u vodi, metanolu, dimetil-sulfoksidu (DMSO). Osim 3- APBA kiseline u ovom radu ispitana je i citotoksičnost spoja indometacina. To je tvar u obliku žutog kristalnog praha, topljiva u otapalima poput kloroforma, acetona i dimetil-sulfoksida (DMSO). Indometacin je lijek koji ima protuupalna, analgetska i antipiretička svojstva, te spada u skupinu nesteroidnih protuupalnih spojeva. U ovom radu, ispitan je citotoksični učinak serije koncentracija 3-APBA i indometacina na stanične linije fibroblasta i keratinocita. Vijabilnost stanica utvđena je pomoću MTT testa, za oba ispitana spoja u rasponu koncentracija od 0,012 mM do 0,391 mM. Za svaki pojedinačni spoj izračunate su vrijednosti koncentracije koja uzrokuje inhibiciju rasta stanica kod vijabilnosti od 50 %. Općenito, svi ispitani spojevi pokazali su veću toksičnost na staničnu liniju keratinocita nego na staničnu liniju fibroblasta.Treba uzeti u obzir i toksični učinak DMSO kao otapala. Najveću toksičnost pokazao je indometacin otopljen u DMSO dok je najnižu toksičnost pokazala 3-APBA otopljena u ultra čistoj vodi.The chemistry of boron compounds is becoming increasingly investigated due to the specific properties of boron and its compounds that can be used in medicine and pharmacy. Boronic acids are chemical compounds containing a trivalent boron atom. Their mild reactivity and stability make boronic acids attractive as synthetic intermediates. Boron compounds possess significant biologically active properties that can be of exceptional benefit in the treatment of many diseases. The compound, 3- aminophenylboronic acid (3-APBA), exists as a white crystalline powder, soluble in water, methanol and dimethyl sulphoxide (DMSO). Another tested compound in this paper is called indomethacin. It is a substance in the form of a yellow crystalline powder, soluble in solvents such as chloroform, acetone, dimethyl sulphoxide (DMSO), etc. Indomethacin is a medicine that has anti-inflammatory, analgesic and antipyretic properties and belongs to a group of non-steroidal anti-inflammatory compounds. In this study, cytotoxic effect of a series of concentrations of 3-APBA and indomethacin on human fibroblasts and keratinocytes cells was tested. The MTT assay showed viability of cells, for both tested compunds in the concentration range of 0,012 mM to 0,391 mM. Concentration values which causes 50% inhibition of cell growth were calculated for each individual compound. All tested compounds showed higher toxicity to the keratinocyte cell line than to the fibroblasts cell line. The toxic effect of DMSO as solvent should also be taken into account. The highest toxicity was shown by indomethacin dissolved in DMSO, while the lowest toxicity was shown by 3-APBA dissolved in ultra-pure water
Analysis of natural soap and industrial toilet soap : bachelor thesis
No full textSapuni su po kemijskom sastavu natrijeve ili kalijeve soli viših masnih kiselina. Dobivaju se procesima bazične hidrolize masti i ulja tj. procesima saponifikacije. Proces saponifikacije je ostao nepromijenjen godinama, no razvitkom svijesti o utjecaju štetnih tvari na zdravlje i ekologiju započela je težnja za što prirodnijim kozmetičkim i higijenskim preparatima. Cilj ovog završnog rada bio je analizirati svojstva sapuna proizvedenih iz biljnih ulja te njihova svojstva usporediti sa svojstvima industrijskog toaletnog sapuna. Sapuni su pripravljani postupkom na hladno. Korišteno je svježe maslinovo ulje, maslinovo ulje starosti dvije godine, kokosovo ulje, palmino ulje te natrijeva lužina i voda. Pripravljeni sapuni su kemijski analizirani i provedena je usporedba njihovih svojstava sa svojstvima industrijskog toaletnog sapuna.Chemically soaps are sodium or potassium salts of higher fatty acids. They are obtained by base catalyzed hydrolysis of fats and oils, i.e. processes of saponification. The process of saponification has remained unchanged for years, but with the development of awareness of the impact of harmfull substances on health and ecology, the aspiration for the more natural cosmetics and hygiene products began. The purpose of this bachelor thesis was to analyze the properties of soaps produced by the synthesis from vegetable oils and to compare them with the properties of industrial toilet soap. Soaps are prepared by the cold process. Fresh olive oil, two-year-old olive oil, coconut oil, palm oil, sodium hydroxide and water were used. The prepared soaps were chemically analyzed and the comparison of their properties with the properties of the industrial toilet soap was performed
Mass spectrometry-based metabolic profiling for disease detection : bachelor thesis
No full textMasena spektrometrija igra važnu ulogu u pronalaženju biomarkera za detekciju bolesti. Visokokvalitetni kvantitativni podaci potrebni su za preciznu analizu metaboličkih smetnji kod pacijenata. Ovaj rad opisuje nedavne napretke u istraživanju metabolizma temeljenom na masenoj spektrometriji s primjenom u detekciji nekoliko najzastupljenijih ljudskih bolesti, s fokusom na istraživanje kohorta, korištene maseno spektrometrijske platforme, statističke analize i identifikaciju razlikovnih metabolita. Sumirani su potencijalni nedavno otkriveni biomarkeri za dijabetes tipa 2, kardiovaskularne bolesti, hepatocelularni karcinom te su raspravljena ograničenja i mogućnosti.Mass spectrometry plays an important role in seeking biomarkers for disease detection. High-quality quantitative data is needed for accurate analysis of metabolic perturbations in patients. This thesis describes recent developments in mass spectrommetry-based metabolomics research with applications to the detection of several major common human diseases, focusing on study cohorts, mass spectrometry platforms utilized, statistical analyses and discriminant metabolite identification. Potential disease biomarkers recently discovered for type 2 diabetes, cardiovascular diseases,hepatocellular carcinoma are summarized and limitations and possibilities are discussed
Gluten in food : bachelor thesis
No full textAlergeni su antigeni proteinskog sastava, bezopasne tvari koje induciraju alergijsku reakciju kod preosjetljivih osoba. Tijekom kontakta obrambenog sustava i alergena dolazi do burne reakcije između protutijela i alergena. Stvara se ogromna količina protutijela koji pripadaju skupini imunoglobulina E i na taj način dolazi do alergijske reakcije. Za hrvatske proizvođače obvezno je označavanje alergena i tvari koje izazivaju intoleranciju od 1. siječnja 2007.god., a vezane su za obveze propisane: Zakonom o hrani, Pravilnikom o označavanju i prezentiranju hrane uz dopune. Gluten je jedan od alergena, po svom sastavu je bjelančevina koja je zastupljena u pšenici, raži i ječmu. U posljednje vrijeme sve više ljudi ima alergijsku reakciju na gluten i zbog toga sve veći broj ljudi prelazi na bezglutensku prehranu koja je ujedno i temeljni način liječenja celijakije. Jedna od najpoznatijih metoda određivanja glutena u namirnicama je tzv. ELISA metoda kojom se određuje prisutnost i količina antigena. Ukoliko prehrambeni proizvod sadrži gluten koji nije propisan pravilnikom ili se utvrdi veća količina glutena od maksimalno dopuštene sukladno tome slijedi povlačenje i/ili opoziv proizvoda s tržišta. U sklopu završnog rada je naveden opoziv proizvoda na primjeru čokolade. Dakle, ukoliko prehrambeni proizvod sadrži veću količinu glutena od maksimalno dopuštene Ministarstvo poljoprivrede je dužno obavijestiti potrošače o prisutnosti proizvoda na tržištu. Kod ljudi koji boluju od celijakije prisutnost glutena u hrani je štetna za zdravlje potrošača te se pritom prehrambeni proizvod opoziva i/ili povlači iz prometa ili tržišta kao što je prikazano na primjeru čokolade.Allergens are antigens of protein composition, harmless substances that trigger an allergic reaction in hypersensitive individuals. During the defence system encounters the allergen, there is a violent reaction between the antibody and the allergen. Huge amounts of antibodies of the immunoglobulin E group are produced and therefore an allergic reaction occurs. For Croatian producers, the labelling of allergens and substances causing intolerance is obligatory from 1 January 2007. related to the obligations arising from: the Food Act, Regulation on the labelling and presentation of foodstuffs with amendments. Gluten is one of the allergens, in its composition it is a protein found in wheat, rye and barley. Recently, there has been more and more peoples are allergic on gluten so they switch to gluten- free diet, which is also a basic method of treating coeliac disease. One of the best-known methods for determining gluten in food is the so-called e.g. ELISA method to determine the presence and amount of the antigen. If a food does not contain gluten as required by the Regulation or if a higher amount of gluten than the maximum permitted amount is detected, the product will be withdrawn and/or recalled from the market. In the context of the final paper, the recall of the product is mentioned using chocolate as an example. Therefore, if a food product contains a higher gluten content than the maximum permitted level, the Ministry of Agriculture is obliged to inform consumers about the presence of the product on the market. For people with coeliac disease, the presence of gluten in food is harmful to health, these foods will be immediately recalled and/or withdrawn from the market, as the example of chocolate shows.
Biological activity of phenylboronic acid : bachelor thesis
No full textCilj ovog završnog rada bio je istražiti literaturu koja se bavi biološkom aktivnosti fenilboronične kiseline. Fenilboronična kiselina je spoj koji ima mnogo pozitivnih svojstava, koja ju čine korisnim farmaceutskim sredstvom za liječenje raka. U završnom radu se navodi kako fenilboronična kiselina može utjecati na migraciju određenih staničnih linija raka. Jedan od problema tijekom liječenja pacijenata od raka je ta što određeni lijekovi mogu negativno utjecati na zdrave stanice i organe, a u završnom radu će navesti, kako fenilboronična kiselina utječe na zdrave stanice te postoji li mogućnost da fenilboronična kiselina ima bolju selektivnost tijekom liječenje od ostalih lijekova. Također uz pomoć dostupne literature i raznih istraživanja utvrdilo se da inhibitori koji sadrže fenilboroničnu kiselinu imaju bolje antivirusno djelovanje od derivata karboksilne kiseline. Svi ovi navodi će biti pobliže objašnjeni u završnom radu.The aim of this thesis was to investigate the literature dealing with the biological activity of phenylboronic acid. Phenylboronic acid is a compound that has many positive properties, which makes it a useful pharmaceutical agent for the treatment of cancer. In this bachelor thesis states how phenylboronic acid can affect the migration of certain cancer cell lines. One of the problems during the treatment of cancer patients is that certain drugs can adversely affect healthy cells and organs, and in the final paper they will state how phenylboronic acid affects healthy cells and whether there is a possibility that phenylboronic acid has better selectivity during treatment than other drugs. . Also with the help of the available literature and various studies, it was found that inhibitors containing phenylboronic acid have better antiviral activity than carboxylic acid derivatives. All these allegations will be explained in more detail in the this thesis.
Phenolic composition of the fruits from genus Rosa : diploma thesis
No full textModeran način života povećava razinu oksidativnog stresa stoga brojne studije nastoje pronaći nove, prirodne supstance koje je lako unijeti u organizam i koje će pomoći ljudskom organizmu u borbi sa slobodnim radikalima. Upravo u te supstance ubrajamo fenolne spojeve koje nalazimo u biljkama. U ovom radu je ispitan fenolni sastav plodova roda Rosa. Analiza je provedena na četiri različita uzorka ploda vrste Rosa canina L. i dva uzorka ploda Rosa hybrida spp. koristeći Folin-Ciocalteu metodu određivanja ukupnih fenola i tekućinsku kromatografiju visoke djelotvornosti (High-performance liquid chromatography, HPLC) metodu za određivanje fenolnog profila. Rezultati pokazuju visoki udio ukupnih fenola kod svih ispitanih uzoraka te je HPLC metodom dokazano prisustvo fenolnih kiselina i flavonoida od kojih su najzastupljeniji galna i protokatehinska kiselina te epikatehin i katehin. U vrstama Rosa hybrida spp. je dokazan veći udio fenolnih spojeva i bolji fenolni profil u usporedbi s Rosa canina vrstama.Modern lifestyle increas oxidative stress level, therefore numerous studies try to find new, natural substances that are easy to consume and help with free radicals. These substances include phenolic compounds found in plants. This paper examine the phenolic composition of Rosa fruits. The analysis was performed on four different fruit samples of Rosa canina L. and two fruit samples Rosa hybrida spp. using the Folin-Ciocaltea method for the determination of total phenols and the High-performance liquid chromatography (HPLC) method for the determination of the phenolic profile. The results show a high proportion of total phenols in all tested samples and the HPLC method proved the presence of some phenolic acids and flavonoids, the most common of which were gallic and protocatechinic acid, and epicatechin and catechin. Rosa hybrida spp. showed a higher total phenolic content and a better phenolic profile compared to Rosa canina species
Influence of yeast strains on sensory properties and composition of volatile compounds of Pošip wine : diploma thesis
No full textPošip je bijela sorta grožđa koja se uglavnom uzgaja na južnim dijelovima otoka Korčule, osobito na području Čare i Smokvice gdje daje vino vrhunske kvalitete čemu svjedoče brojne nagrade i priznanja. Vino je osebujnog okusa sa svojstvenim aromama suhih marelica i smokava, blistavo, slamnate- zlatnožute boje. U posljednje vrijeme proizvođači rade brojne eksperimente kako bi utvrdili optimalne uvjete za provedbu fermentacije i odabrali odgovarajući soj kvasaca kojima bi se postigao maksimum sortnih i sekundarnih aroma i u konačnici visokokvalitetan proizvod. U ovom radu su korištena dva vina sorte Pošip koja su proizvedena s različitim kvascima. Za određivanje razlike utjecaja različitih sojeva kvasaca provedena je senzorska analiza i izolacija hlapljivih organskih spojeva mikroekstrakcijom vršnih para na krutoj fazi (HS-SPME). Aromatični profil uzoraka vina Pošip određen je vezanim sustavom plinska kromatografija-spektrometrija masa (GC -MS). Najveći intenziteti mirisnih i okusnih obilježja u vinima su bili „voćno“ i „cvjetno“. Uzorak X-16 imao je nešto veće intenzitete „voćnosti“ dok su „cvjetni“ intenziteti bili viši u uzorku X-5. Najzastupljeniji spojevi u oba uzorka vina su spojevi sekundarne arome. U skupini estera dominiraju etilni esteri viših masnih kiselina (2-metilbutil-oktanoat, etil-heksadekanoat, etil-dec-9-enoat, etil-tetradekanoat, etil-linoleat). Najviši udio u oba uzorka vina imao je ester 2-metilbutil-oktanoat čiji je senzorski opis „voćno“. U uzorku X-16 utvrđen je viši udio izoamil-acetata što se može dovesti u korelaciju s rezultatima senzorske analize gdje su obilježja „voćnosti“ viših intenziteta u uzorku X-16. Dobiveni rezultati pokazuju kako različiti kvasci različito doprinose aromi vina.Pošip is a white grape variety that is mainly grown in the southern parts of the island of Korčula, especially in the area of Čara and Smokvica, where it produces top quality wine, as evidenced by numerous awards. The wine has a distinctive taste with its aromas of dried apricots and figs, bright, straw-golden yellow in color. Recently, producers have been conducting numerous experiments to determine the optimal conditions for fermentations and to select the appropriate yeast strain that would achieve the maximum of sorted and secondary aromas and ultimately a high quality product. In this paper, two Pošip wines produced with different yeast strains were used. To determine the influence of different yeast strains, sensory analysis and isolation of volatile organic compounds by headspace solid phase microextraction (HS-SPME) were performed. The aromatic profile of Pošip wine samples was determined by the coupled gas chromatography-mass spectrometry (GC -MS) system. The highest intensities of fragrant and tasty attributes in the wines were "fruity" and "floral". The X-16 sample had slightly higher “fruitiness” intensities while the “floral” intensities were higher in the X-5 sample. The most common compounds in both wine samples are secondary aroma compounds. The group of esters is dominated by ethyl esters of higher fatty acids (2-methylbutyl octanoate, ethyl hexadecanoate, ethyl-dec- 9-enoate, ethyl tetradecanoate, ethyl linoleate). The highest share in both wine samples had the ester 2- methylbutyl octanoate, whose sensory description is "fruity". A higher content of isoamyl acetate was found in the X-16 sample, which can be correlated with the results of sensory analyzes where the "fruitiness" of higher intensities in the X-16 sample was marked. The obtained results showed how different yeast strains contribute differently to the aroma of wine
Electrochemical properties of Ti and Ti-6V-4Al alloy : diploma thesis
No full textDugotrajna stabilnost oksidnih filmova na Ti i legurama Ti ima odlučujuću ulogu pri odabiru ovih biokompatibilnih materijala za izradu različitih medicinskih i dentalnih implantata. U ovom radu ispitano je elektrokemijsko i korozijsko ponašanje Ti i Ti-6V-4Al legure u slanoj otopini fosfatnog pufera (PBS, pH = 7.4) na 37 o C (tj. u simuliranoj fiziološkoj otopini u ljudskom tijelu) praćenjem vremenske promjene potencijala otvorenog strujnog kruga, primjenom polarizacijih metoda te elektrokemijske impedancijske spektroskopije. Oštećenja na površini metala nastala polarizacijom potvrđena su optičkim i pretražnim elektronskim mikroskopom, dok je elementarni sastav oksidnog filma na površini pojedinog uzorka određen EDS analizom. Elektrokemijsko i korozijsko ponašanje Ti i Ti-6V-4Al legure posljedica je formiranja površinskog oksidnog filma koji ima dvoslojnu strukturu, a sastoji se od unutarnjeg tankog barijernog sloja i vanjskog poroznog sloja. Koroziju Ti i Ti-6V-4Al legure uglavnom sprječava unutarnji barijerni sloj, čija debljina i otpor naglo rastu u prvih nekoliko dana izlaganja PBS otopini. Kod dužih vremena izalaganja PBS otopini dolazi do naknadnog sređivanja strukture barijernog sloja i daljnjeg rasta njegovog otpora. U usporedbi Ti-6V-4Al legurom, čisti Ti pokazuje veću korozijsku stabilnost.The long-term stability of oxide films on Ti and Ti alloys plays a crucial role in the use of these biocompatible materials for the manufacture of various implants in medical and dental practice. The electrochemical and corrosion behavior of Ti and Ti-6V-4Al alloy in phosphate buffer solution (PBS, pH = 7.4) at 37 o C (i.e. in simulated physiological solution in the human body) was examined using open circuit potential measurements, polarization and electrochemical impedance spectroscopy methods. The polarization surface damages were verified by optical and scanning electron microscopy, while the elemental composition of oxide film on the surface of each sample was determined by EDS analysis. The electrochemical and corrosion behavior of Ti and Ti-6V-4Al alloys is due to the formation of two- layer model of surface oxide film, consisting of a thin barrier-type inner layer and a porous outer layer. Corrosion of Ti and Ti-6V-4Al alloy is mainly prevented by the inner barrier layer, whose thickness and resistance increase sharply in the first few days of exposure to PBS solution. With longer exposure times to the PBS solution, the structure of the barrier layer subsequently settles and its resistance increases further. Compared to Ti-6V-4Al alloy, pure Ti shows greater corrosion stability
Biological potential of selected red algae : diploma thesis
No full textCrvene alge (Rhodophyta) su široko rasprostranjena grupa jednostaničnih i višestaničnih vodenih fotoautotrofnih organizama. Odličan su izvor bioaktivnih komponenti kao što su vitamini, minerali, vlakna i polisaharidi. Upravo njihov sastav ih čini odličnim izvorom antioksidansa. U ovom radu određen je sadržaj ukupnih fenola Folin-Ciocalteu metodom te antioksidacijski potencijal tri vrste crvenih algi (Laurencia obtusa, Corallina officinalis i Peyssonnelia squamaria) iz Jadranskog mora, korištenjem DPPH (eng. 2,2,- Diphenyl-picrylhydrazyl assay), FRAP (eng. Ferric-reducing antioxidant power) i ORAC (eng. Oxygen radical absorbing capacity) metoda. Dodatno, određen je i utjecaj dviju ekstrakcija, ekstrakcije potpomognute ultrazvukom (UAE) i ekstrakcije potpomognute mikrovalovima (MAE) na ukupan broj fenola. Iz rezultata se može zaključiti da od tri ispitivane vrste alga P. squamaria ima najbolji antioksidacijski potencijal, a MAE se pokazala kao bolja metoda za ekstrakciju jer omogućava ekstrahiranje veće količine fenola, a time i veću antioksidacijsku aktivnost odabranih crvenih algi.Red algae (Rhodophyta) are a widespread group of unicellular and multicellular aquatic photoautotrophic organisms. They are an excellent source of bioactive components such as vitamins, minerals, fiber and polysaccharides. It is their composition that makes them an excellent source of antioxidants. In this paper, the content of total phenols via Folin-Ciocalteu method and the antioxidant potential of three species of red algae from Adriatic (Laurencia obtusa, Corallina officinalis and Peyssonnelia squamaria) were determined using DPPH (2.2, -Diphenyl-picrylhydrazyl assay), FRAP (Ferric-reducing antioxidant power) and ORAC (Oxygen radical absorbing capacity) methods. In addition, the influence of two extractions, ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) on the total phenolics was determined. From the results it can be concluded that of the three tested algae species P. squamaria had the best antioxidant potential, and MAE proved to be a better method for extraction because it allows extraction of higher amounts of phenols, and thus higher antioxidant activity of selected red algae