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Preparation of a fluorescent indicator for the determination of H2S
No full textU ovom zavrbnom radu opisana je priprava fluorescentnog indikatora za detekciju unutarstani nog H2S. Kao fluorofor u procesu dizajna fluorescentnog indikatora odabran je 1,8-naftalimidni sustav, dok je kao receptor odgovoran za reakciju s ciljnim analitom, H2S, odabrana azidna skupina. Osnovni naftalimidni sustav strukturno je modificiran uvođenjem anilinskih derivata na dubikov atom. Kao polazni spoj za pripravu ciljnih spojeva odabran je 4-brom-1,8-naftalanhidrid dok kao anilinski derivati odabrani su p-metilanilin i p-kloranilin. Za pripravu ciljnih derivata koribten je sintetski put koji podrazumijeva pripravu azidnog derivata 4-brom-1,8- naftalanhidrida, spoja 1, te njegovu reakciju s odabranim anilinskim derivatima. Ovakav sintetski put rezultirao je uspjebnom pripravom spoja 2, s metilnom skupinom na arilnom dijelu molekule, dok spoj b, s atomom klora na arilnom dijelu molekule, nije uspjebno pripravljen predlo~enim sintetskim putem. S ciljem priprave spoja b predlo~en je i novi sintetski put koji podrazumijeva reakciju polaznog spoja, 4-brom-1,8-naftalanhidrida s pkloranilinom, nakon ega slijedi uvođenje azidne skupine u strukturu naftalimidnog derivata. Spoj b nije uspjebno pripravljen niti novim predlo~enim sintetskim putem. Ciljni produkt, spoj 2, koribten je za fluorescentnu detekciju generiranog H2S. Strukture pripravljenih spojeva pretpostavljene su NMR spektroskopijom (1H i 13C).In this thesis the preparation of a fluorescent indicator for the detection of intracellular H2S is described. The 1,8-naphthalimide system was chosen as the fluorophore in the fluorescent indicator design process, while the azide group was chosen as the receptor responsible for the reaction with the target analyte, H2S. The basic naphthalimide system is structurally modified by introduction of aniline derivatives on the nitrogen atom. 4-bromo-1,8-naphthalic anhydride was selected as the starting compound for the preparation of the target compounds, while p-methylaniline and p-chloroaniline were selected as aniline derivatives. For the preparation of target derivatives synthetic pathway which implies preparation of the azide derivative of 4-bromo-1,8-naphthalanhydride, compound 1, and its reaction with selected aniline derivatives was used. This synthetic route resulted in the successful preparation of compound 2, with a methyl group on the aryl part of the molecule, while compound b, with a chlorine atom on the aryl part of the molecule, was not successfully prepared using the proposed synthetic route. With the aim of preparing compound b, a novel synthetic route was proposed, which involves the reaction of the starting compound, 4-bromo-1,8-naphthalanhydride with p-chloroaniline, followed by the introduction of an azide group into the structure of the naphthalimide derivative. Compound b was not successfully prepared even by the novel proposed synthetic route. The target product, compound 2, was used for fluorescence detection of generated H2S. The structures of the prepared compounds were assumed by NMR spectroscopy ( 1H and 13C)
Chemistry of immunological reactions to tumors
No full textU ovom radu istraduju se biokemijski procesi koje se odvijaju u organizmu prije te tijekom nastanka tumora. Opisuje se imunologija organizma te preduvjeti koji su potrebni za nastanak tumora. Istradene su molekule koje su uklju ene u biokemijske procese nastanka tumora, patogeneza te kancerogeneza. Imunolobki sustav mode prepoznati maligno transformirane stanice zahvaljuju i antigenima koji razlikuju tumorsku stanicu od normalne. Upala u mikrookrudenju tumora uzrokuje nakupljanje imunolobkih stanica na tom mjestu, stoga tumor ima neke mehanizme imunolobke supresije u mikrookrudenju kako bi izbjegao imunolobki nadzor. Zaklju no tome ukoliko je prisutan stani ni stres, mutacije, genetske predispozicije te razni imbenici povezani sa samim kemijskim molekulama to e rezultirati pojavom procesa koji ine razliku izme u tumora i normalnih stanica. Fosfatidilserin (PS) je fosfolipid koji se u normalnim stanicama nalazi na unutarnjoj strani membrane, ali tijekom apoptoze prelazi na vanjsku stranu, signaliziraju i fagocitima za uklanjanje stanice. PS tako er igra ulogu u imunosupresiji, bto tumorske stanice iskoribtavaju za izbjegavanje imunolobkog odgovora. NK stanice su klju ne za imunolobku obranu, prepoznaju i ubijaju tumorske i zaradene stanice. B7-H6 protein, prisutan na tumorskim stanicama, aktivira NK stanice putem NKp30 receptora, poti u i njihovu citotoksi nost.This thesis investigates the biochemical processes occurring in the body before and during tumor development. It describes the body's immunology and the prerequisites necessary for tumor formation. Molecules involved in the biochemical processes of tumorigenesis, pathogenesis, and carcinogenesis are explored. The immune system can recognize malignantly transformed cells thanks to antigens that distinguish tumor cells from normal ones. Inflammation in the tumor microenvironment causes immune cells to accumulate at that site, prompting tumors to develop mechanisms of immune suppression in the microenvironment to evade immune surveillance. Consequently, if cellular stress, mutations, genetic predispositions, and various factors related to chemical molecules are present, they will result in processes that differentiate tumors from normal cells. Phosphatidylserine (PS) is a phospholipid that, in normal cells, is found on the inner side of the membrane but during apoptosis moves to the outer side, signaling phagocytes to remove the cell. PS also plays a role in immunosuppression, which tumor cells exploit to evade the immune response. NK cells are crucial for immune defense, recognizing and killing tumor and infected cells. The B7-H6 protein, present on tumor cells, activates NK cells via the NKp30 receptor, promoting their cytotoxicity
Electrochemical characterization of p-coumaric acid
No full textOvim radom ispitivana su elektrokemijska svojstva p-kumarinske kiseline cikličkom i diferencijalnom pulsnom voltametrijom. Cilj ovog diplomskog rada bio je ispitati utjecaj pH vrijednosti, brzine polarizacije elektrode i koncentracije p-kumarinske kiseline na njena oksido-redukcijska svojstva, te ispitati adsorpciju p-kumarinske kiseline na površinu radne elektrode i detektirati p-kumarinsku kiselinu u realnim uzorcima. Mjerenja su provedena pomoću PalmSens potenciostata/galvanostata kontroliranog s PSTrace 1.2. računalnim programom. Mjerenja su izvedena u elektrokemijskoj ćeliji s troelektrodnim sustavom koji se sastoji od radne elektrode od staklastog ugljika, referentne Ag/AgCl elektrode i protuelektrode platinske žice. Sustav je prije svakog mjerenja propuhan argonom visoke čistoće (φAr = 99,999 %). Ciklički voltamogrami pokazali su oksidacijski strujni vrh, što ukazuje na oksidaciju hidroksilne skupine p-kumarinske kiseline, pri čemu je utvrđeno da je proces kontroliran difuzijom. Diferencijalni pulsni voltamogrami pokazali su da se visina oksidacijskog strujnog vrha p-kumarinske kiseline mijenja s promjenom pH vrijednosti, pri čemu je optimalna pH vrijednost za oksidaciju pri pH = 3,0. U realnim uzorcima (sok od jabuke, mrkve, limuna i šipka) detektirana je p-kumarinska kiselina u koncentracijskom području od 2 μM. do 9 μM.In this study, the electrochemical properties of p-coumaric acid were determined by using cyclic and differential pulse voltammetry. The study aimed to examine the influence of pH, scan rate, and p-coumaric acid concentration on its redox properties, to study the adsorption of p-coumaric acid on the surface of the working electrode and to detect p-coumaric acid in real samples. Measurements were performed by using a PalmSens potentiostat/galvanostat controlled by the PSTrace 1.2 software. The measurements were conducted in an electrochemical cell with a three-electrode system consisting of a glassy carbon working electrode, an Ag/AgCl reference electrode, and a platinum wire counter electrode. Before each measurement, the system was purged with high-purity argon (φAr = 99.999%). Cyclic voltammograms showed an oxidation peak corresponding to the oxidation of the hydroxyl group of p-coumaric acid, indicating that the process is diffusion-controlled. Differential pulse voltammograms revealed that the height of the oxidation peak of p-coumaric acid changes with pH, while the optimal pH for oxidation was at the pH= 3.0. In real samples (apple juice, carrot juice, lemon juice, and pomegranate juice), p-coumaric acid was detected in the concentration range from 2 μM to 9 μM
Food toxicology and safety of food products
No full textHrana je nešto što svakodnevno konzumiramo stoga je bitno znati kakve sve supstance unosimo u organizam njenom konzumacijom. Prilikom proizvodnje, skladištenja i transporta hrana se može kontaminirati na razne načine. Neke kontaminacije neće imati posljedice na organizam, dok unos toksičnih kontaminanata ovisno o dozi može biti koban. Toksikologija hrane proučava način ulaska tokiskanata iz hrane u organizam, način raspodjele, metabolizam i izlučivanje istih. Toksikanti koji kontaminiraju hranu mogu se prirodno nalaziti u namirnicama, dospjeti u namirnice iz zagađenog okoliša ili utjecajem čovjeka. Hrana može biti zagađena mikotoksinima, teškim metalima, pesticidima, toksinima biljnog i životinjskog podrijetla poput lektina, oksalata, histamina i priona. Kako bi se proizvela sigurna i zdravstveno ispravna hrana, proizvođači hrane moraju poštovati razne zakone propisane od strane mjerodavnih službi. Službe koje nadziru sigurnost hrane i prehrambenih proizvoda u Europi su: Vijeće ministara, Europska komisija i Europski parlament, a u Republici Hrvatskoj: Ministarstvo poljoprivrede, Ministarstvo zdravlja i Hrvatska agencija za sigurnost hrane. HACCP (engl. Hazard Analysis and Critical Control Point) također ima veliku ulogu u reguliranju proizvodnje sigurne i zdravstveno ispravne hrane.Food is something that we consume every day, therefore it is important to know which substances we introduce into the body by consuming it. During production, storage and transportation, food can be contaminated in various ways. Some contaminations will have no consequences on the organism, while the intake of toxic contaminants depending on the dose can be fatal. Food toxicology studies the way toxicants from food enter the body, the way they are distributed, their metabolism and excretion. Toxicants that contaminate food can be found naturally in food, get into food from a polluted environment or by human influence. Food can be contaminated with mycotoxins, heavy metals, pesticides, and plant and animal toxins such as lectins, oxalates, histamine and prions. To produce safe and healthy food, food manufacturers must comply with various laws prescribed by the competent authorities. The services that monitor the safety of food and food products in Europe are the Council of Ministers, the European Commission and the European Parliament, and in the Republic of Croatia: the Ministry of Agriculture, the Ministry of Health and the Croatian Food Safety Agency. HACCP (Hazard Analysis and Critical Control Point) also plays a major role in regulating the production of safe and healthy food
Enzymes in honey and their reactions
No full textU ovom zavrbnom radu istražuju se enzimi prisutni u medu, s posebnim naglaskom na njihovu kataliti ku aktivnost i utjecaj na kvalitetu meda. Prou avaju se metode određivanja enzimske aktivnosti, kao i utjecaj skladibtenja i obrade meda na o uvanje te aktivnosti. Da bi se u potpunosti razumjela važnost enzima, potrebno je poznavati cjelokupan kemijski sastav meda, reakcije koje se u njemu odvijaju te njihove produkte, koji zajedno s enzimima oblikuju njegovu kakvo u. U fokusu su enzimi poput invertaze, dijastaze, katalaze i glukoza-oksidaze, ije su specifi ne funkcije i reakcije detaljno analizirane, uzimaju i u obzir uvjete djelovanja poput temperature, pH, obrade i skladibtenja meda. Pregledom dostupne literature, istaknuta je klju na uloga enzima u o uvanju kvalitete i trajnosti meda. Također, razmatraju se metode za analizu enzimske aktivnosti i faktori koji utje u na njihovu stabilnost.In this final paper, enzymes present in honey are studied, with a particular focus on their catalytic activity and their impact on honey quality. The methods for determining enzyme activity are examined, as well as the effects of storage and processing of honey on the preservation of this activity. To fully understand the importance of enzymes, it is essential to be familiar with the complete chemical composition of honey, the reactions that occur within it, and their products, which, together with enzymes, shape its overall quality. The focus is on enzymes such as invertase, diastase, catalase, and glucose oxidase, whose specific functions and reactions are thoroughly analyzed, considering conditions like temperature, pH, processing, and honey storage. Through the analysis of available literature, the critical role of enzymes in maintaining honey's quality and longevity is highlighted. Additionally, methods for analyzing enzyme activity and the factors influencing their stability are considered
The influence of neodymium on the structure of high-entropy oxides
No full textVisokoentropijski oksidi (HEO) definirani su kao materijali kod kojih konfiguracijska entropija ima važnu ulogu u formiranju i stabilnosti prilikom nastanka jednofaznog spoja. Izgrađeni su od minimalno pet elemenata koji dijele kationsko mjesto u kristalnoj rešetki. U ovom radu su sintetizirana četiri spoja visokoentropijskih oksida u osnovi cerijevog dioksida te je istražen utjecaj množinskog udjela neodimija na strukturna i katalitička svojstva HEO. Spojevi su sintetizirani koristeći modificiranu sol-gel sintezu. Dobiveni spojevi su karakterizirani putem rentgenske difrakcije u prahu, određivanjem termičke stabilnosti te analizom površine i optičkih svojstava. Sintetiziranim HEO spojevima je potvrđena fotokatalitička aktivnost na razgradnju organskih bojila metilensko modrilo i rodamin B te je uspoređena s vrijednostima katalitičke aktivnosti cerijevog dioksida. Dokazano je kako HEO spojevi imaju modificirana strukturna, površinska i optička svojstva te poboljšanu katalitičku aktivnost u odnosu na cerijev dioksid.High-entropy oxides (HEO) are defined as materials where configurational entropy plays an important role in the formation and stability of a single-phase compound. They are built from a minimum of five elements that share a cation site in the crystal lattice. In this work, four compounds of high-entropy oxides based on ceria were synthesized, and the influence of the molar ratio of neodymium on the structural and catalytic properties of HEO was investigated. The compounds were synthesized using a modified sol-gel synthesis. The obtained compounds were characterized by X-ray powder diffraction, determination of thermal stability and analysis of surface and optical properties. The photocatalytic activity for the degradation of organic dyes methylene blue and rhodamine B was confirmed by the synthesized HEO compounds and was compared with the values of the catalytic activity of pure ceria. It has been proven that HEO compounds have modified structural, surface and optical properties and improved catalytic activity compared to pure ceria
Application of "narrow gap" electrodes for electrochemical analysis in liquid media with low electrical conductivity
No full textOvaj rad pokriva razli ite aspekte elektrokemijske analize, kao bto su komponente elektrokemijskih elija, uklju uju i radne, referentne i pomo ne elektrode, otapala i elektrolite. Također daje pregled nekoliko elektrokemijskih tehnika kao bto su diferencijalna pulsna i pravokutna voltametrija, stripping voltametrija, amperometrija i upotreba narrow gap elektroda. Također se bavi principima galvanskih i elektrokemijskih lanaka, raspravljaju i o njihovim konfiguracijama, koribtenim materijalima i va~nosti potencijala elektrode. U eksperimentalnom dijelu opisani su materijali i metode koribtene za ispitivanje u inkovitosti narrow gap elektroda. Cilj istra~ivanja je utvrditi utjecaj udaljenosti i koncentracije pomo nih elektrolita na ja inu odziva dobivenog cikli kom voltametrijom. Kao pomo na elektroda koribtena je platinska vrpca debljine 0,1 mm, birine 3 mm i duljine 25 mm dok je ulogu radne elektrode obavljala platinska disk elektroda promjera 50 mikrometara. Mjerenja su izvođena u rasponu potencijala od 0 do 0.6 V uz konstantnu brzinu polarizacije od 50mV/s. Faktor koji se mijenjao bila je udaljenost radne i pomo ne elektrode. Diplomski rad zavrbava sa~etkom gdje su rezimirani svi rezultati uz naglasak na potencijalna poboljbanja u metodama elektrokemijske analize koja ove elektrode nude.This paper covers various aspects of electrochemical analysis, including the components of electrochemical cells, such as working, reference and auxiliary electrodes, solvents and electrolytes. It also provides an overview of several electrochemical techniques such as differential pulse and rectangular voltammetry, stripping voltammetry, amperometry and the use of narrow gap electrodes. Additionally, it discusses the principles of galvanic and electrochemical articles, discussing their configurations, materials used, and the significance of electrode potential. In the experimental part, the materials and methods used for testing the efficiency of narrow gap electrodes are described. The goal of the research is to determine the influence of distance and the concentration of auxiliary electrolytes on the response obtained by cyclic voltammetry. A platinum ribbon with a thickness of 0.1 mm, a width of 3 mm and a length of 25 mm was used as the auxiliary electrode, while a platinum disk electrode with a diameter of 50 micrometers served as the working electrode. Measurements were performed in the potential range from 0 to 0.6V with a constant value of the scan rate of 50 mV/s. The factor that was varied was the distance between the working and auxiliary electrodes. The thesis ends with a summary where all results are summarized with an emphasis
Precipitation of the unstable hydrated phase of calcium oxalate
No full textBiomineralizacija je proces nastajanja funkcionalnih biominerala u živim organizmima (kosti, zubi, školjke). U slučaju da dođe do stvaranja neželjenih biominerala govorimo o patološkoj biomineralizaciji (karijes, kamenci, ...). Bubrežni kamenci su primjer patološke biomineralizacije koji uzrokuju kroničnu bolest - urolitijazu. U današnje vrijeme zbog načina života, loše prehrane i raznih vanjskih čimbenika bubrežni kamenci su postali sve češći pojam rasprave. U 80% slučajeva bubrežni kamenci su kalcij oksalatnog sastava. U bubrežnim kamencima najčešće prevladavaju kalcijev oksalat monohidrat (COM) i kalcijev oksalat dihidrat (COD), dok se kalcijev oksalat trihidrat (COT) vrlo rijetko nađe u sastavu kamenaca, ali je pretpostavka da je on prvi oblik koji nastane te transformira u stabilniji oblik. U ovom diplomskom radu cilj je bio sintetizirati nestabilnu hidratnu fazu u što čišćem obliku te analizama optičke mikroskopije, infracrvene spektroskopije, rendgenske difrakcije i termogravimetrijske analize okarakterizirati dobivene kristale i istražiti njihova svojstva. Provedene su sinteze pri tri temperature (25; 36,5 i 48 ℃) i tri ionske jakosti (0,01; 0,05 i 0,1 mol dm-3). Zaključeno je da pri 25 i 36,5 ℃ nastaje COT dok povišenjem temperature na 48 ℃ nastaje COM neovisno o ionskoj jakosti.Biomineralization is the process of formation of functional biominerals in living organisms (bones, teeth, shells). When undesirable biominerals are formed, we are talking about pathological biomineralization (caries, stones, ...). Kidney stones are an example of pathological biomineralization that causes a chronic disease - urolithiasis. Nowadays, kidney stones are an increasingly frequent topic of conversation due to lifestyle, poor diet and various external factors. In 80% of cases, kidney stones are calcium oxalate. In kidney stones, calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) predominate most frequently, while calcium oxalate trihydrate (COT) is rarely found in the composition of stones, but it is believed to be the first hydrate phase formed and then transforms into a more stable form. The aim of this work was to synthesize the unstable hydrate phase in as pure form as possible and to characterize the crystals obtained and study their properties using optical microscopy, infrared spectroscopy, X-ray diffraction and thermogravimetric analyzes. The syntheses were carried out at three temperatures (25, 36.5 and 48 ℃) and three ionic strengths (0.01, 0.05 and 0.1 mol dm-3). It was found that COT is formed at 25 and 36.5 ℃, while increasing the temperature to 48℃ produces COM regardless of the ionic strength
Analysis of water for pharmaceutical industry according to the European pharmacopoeia
No full textEuropska farmakopeja je zbirka tekstova o kvalitativnom i kvantitativnom sastavu lijekova, o ispitivanjima koja se provode na lijekovima, o sirovinama koje se koriste u samoj proizvodnji lijekova, te o međuproduktima sinteze lijekova i medicinskih pripravaka. Prema europskoj farmakopeji razlikuju se 3 vrste voda: pro ia ena voda, voda za injekcije, voda za pripravu ekstrakata. U ovom radu ispitivala se voda iz monografija pro ia ene vode. Analiziralo se ukupni organski ugljik, elektri na vodljivost, prisutnost nitrata, sulfata, kalcija i magnezija, klorida, oksidiraju ih tvari, kiselost ili lu~natost i ostatak nakon uparavanja. Svi dobiveni rezultati odgovaraju zadanim normama iz europske farmakopeje, te se time mo~e zaklju iti kako je voda iz farmaceutske tvrtke Yasenka pogodna za upotrebu u farmaceutskoj industriji.European pharmacopoeia is a collection of texts about qualitative and quantitaive composition of drugs, about scanning on drugs, raw materials used in pharmaceutical industry, and about intermediate products in making drugs and medicines. There are 3 tipes of water in European pharmacopoeia: Purified water, Water for injections, water for preparation of extracts. In this paper was used only purified water. We were testing total organic carbon, conductivity, nitrates, acidity or alkalinity, sulfates, calcium and magnesium, chlorides, oxidisable substances, ammonium and residue on evaporation. Results of analysis are compactibile with norms given in pharmacopoeia, and proving us that water from pharmaceutical company Yasenka is suitable for using in pharmaceutical industry
Synthesis and characterization of N,S -donor macrocycles
No full textStruktura makrocikli kih spojeva je takva da se u njihovoj sredini nalazi bupljina zbog koje su oni pogodni spojevi za ubacivanje raznih manjih molekula, iona i sli no. Ukoliko se metalni ioni vežu na makrocikli ki spoj dolazi do pove anja njihove termodinami ke stabilnosti u odnosu na ione vezane na acikli ki spoj te se ta pojava naziva makrocikli kim efektom. Po etak sinteze N2S2 makrocikli kih spojeva obuhva a dodatak polimetilnog mosta između dva atoma sumpora tiosalicilne kiseline te se zatim nastala dikiselina reducira do alkohola koji oksidacijom uz manganov oksid prelazi u dialdehid. Kondenzacijom dialdehida i diamina dolazi do zatvaranja prstena i nastanka makrocikli ke Schiffove baze. U ovom radu je također pokazano da je N,S-donorne makrocikli ke spojeve mogu e pripraviti direktnom reakcijom dikiseline s diaminima.The structure of macrocyclic compounds is such that their middle has a cavity which makes them suitable for insertion of various smaller compounds and ions. If metal ions are coordinated to a macrocyclic compound, their thermodynamic stability increases in comparison to ions coordinated to an acyclic compound. This phenomenon is called the macrocyclic effect. The beginning of the synthesis of N2S2 macrocyclic compounds includes the addition of a polymethyl bridge between two sulfur atoms in the thiosalicylic acid after which the resulting diacid is reduced to an alcohol, and then into a dialdehyde by oxidation with manganese oxide. Condensation of dialdehyde and diamine results in ring closure and the formation of a macrocyclic Schiff base. In this work it was also demonstrated that the N,S-donor macrocycles can be obtained by direct reaction of diacid and diamine