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Mehanochemical synthesis of calcium oxalate from calcium sulfate
No full textKalcijevi oksalati su sastavni dio bubrežnih kamenaca i oni su kalcijeve soli oksalne kiseline. Sve više ljudi u današnje vrijeme ima problema sa bubrežnim kamencima stoga su istraživanja na tu temu sve intenzivnija, najviše se istražuju procesi taloženja kalcijevih oksalata te načini njihova mogućeg uklanjanja ili prevencije njihova nastanka. U medicinskom smislu ovaj problem se naziva urolitijaza ili nefrolitijaza. Ovisno o uvjetima, kalcijev oksalat može kristalizirati u tri hidratna oblika, kalcijev oksalat monohidrat (COM) koji je termodinamički najstabilniji, te metastabilni dihidrat (COD) i trihidrat (COT) koji se vrlo rijetko može naći u sastavu bubrežnih kamenaca. U ovom radu je cilj bio provjeriti koji hidratni oblik kalcijeva oksalata nastaje mehanokemijskom sintezom i to na dva načina, bez dodatka otapala (samo praškasti reaktanti) i s dodatkom minimalne količine otapala, u ovom slučaju vode. Dobiveni rezultati su obrađeni i interpretirani FT-IR spektroskopijom, termogravimetrijskom analizom te optičkom mikroskopijom.Calcium oxalates are components of kidney stones and they are calcium salts of oxalic acid. Nowadays more and more people have problems with kidney stones therefore research on this subject are more intensive, mainly precipitation processes of calcium oxalate and the ways of their possible removal or prevention of crystal growth. In medical way this problem is known as urolithiasis of nefrolithiasis. Depending on conditions, calcium oxalate cristallizes in three hidrate forms, calcium oxalate monohydrate (COM) which is thermodynamically most stable, and metastable dihydrate (COD) and trihydrate (COT) which is the rarest to be found in kidney stone composition. The goal of this work was to see which hydrate form of calcium oxalate will form by mechanochemical synthesis and it was done in two ways, without adding minimum quantity of solvent (only pulverised reactants) and with adding a minimum quantity of water, in this case water. Results were processed and interpreted with FT-IR spectroscopy, thermogravimetric analysis and optical microscopy
Synthesis and chemical modification of silica and biodegradiable nanoparticles
No full textSilikatne nanočestice su sintetizirane hidrolizom alkil silikata i postupnom kondenzacijom silikatne kiseline u alkoholnoj otopini uz amonijak kao katalizator. Promjena koncentracije amonijaka u rasponu od 0,05 do 0,70 uzrokuje promjenu veličine čestica od 13 nm do 87 nm. Funkcionalizacija silikatnih nanočestica je izvršena dodavanjem modifikatora nakon završene sinteze čestica. Matematičkim izračunima, podešavanjem pH vrijednosti i mjerenjem zeta potencijala postavljeni su uvjeti kontrolirane agregacije. Kontrolirana agregacija temelji se na elektrostatskim privlačnim silama između pozitivno i negativno nabijenih čestica koje tvore određeni uzorak agregiranja. Kitozanske nanočestice pripravljene su iz emulzije isparavanjem otapala, povećavanjem koncentracije polisorbata 20 u intervalu od 1∙ do 5∙ su dobivene kitozanske nanočestice veličine od 32,67 nm do 78,66 nm s 0,44% masenog udjela kitozana. Čestice su okarakterizirane dinamičkim raspršenjem svjetlosti (DLS) i transmisijskim elektronskim mikroskopom (TEM), mjerenja zeta potencijala izvršena su s elektroforetskim raspršenjem svjetlosti (ELS) te je kemijska modifikacija potvrđena infracrvenom spektroskopijom s Fourierovom transformacijom (FT-IR). Na kraju rada, opisan je i metodički dio na temu "Građa atoma" za prvi razred gimnazijskog programa srednje škole.Silica nanoparticles are prepared with hydrolysis of alkyl silica followed by subsequent condensation silicic acid in alcohol with ammonia catalyst. Ammonia concentration ranging from 0,05 to 0,70 , causes a change in particles size from 13 nm to 87 nm. Silica nanoparticles are functionalized by post-modification. Mathematical calculation, adjusting pH and zeta potential measurement are necessary for controled aggregation. Electrostatic attractive forces between positive and negative particles are basis for controled agreggation with pattern. Emulgation solvent evaporation is method for preparation chitosan nanoparticles, changing concentration polysorbate 20 from 1∙ to 5∙ , resulted in particles size from 32,67 nm to 78,66 nm, with 0,44% chitosan. Particles are characterized with dynamic light scattering (DLS) and transmission electron microscopy (TEM), electrophoretic light scattering (ELS) is used to measure zeta potential, and chemical modification is confirmed with Fourier-transform infrared spectroscopy (FT-IR). Thesis contains a part with teaching method on subject "Atom structure" for first class of high school
Determination of anionic surfactants using direct potentiomerty in municipal wastrwater
No full textUspoređena su tri potenciometrijska senzora (bazirana na tetraoktadecilamonijevom tetrafenilboratu, višestjenčanim ugljikovim nanocjevčicama (MWCNT) funkcionaliziranim sulfatnom skupinom i cetilpiridinijevim ionom te dimetildioktadecilamonijevom tetrafenilboratu (DDA-TPB) s dodatkom ugljikovih nanočestica kao senzorskim materijalom) kako bi se odabrao najpogodniji za određivanje anionskih tenzida u komunalnim otpadnim vodama. Izabran je potenciometrijski senzor koji se bazira na ionskom paru DDA-TPB kao elektroaktivnoj komponenti i o-nitrofeniloktileteru (o-NPOE) kao plastifikatoru, uz dodatak ugljikovih nanočestica. Određivanje anionskih tenzida u komunalnim otpadnim vodama provedeno je koristeći tri različite metode: potenciometrijska titracija, direktna potenciometrija i standardna spektrofotometrijska metilensko plavo (MBAS) metoda. Pri potenciometrijskim titracijama korištena je standardna otopina cetilpiridinijeva klorida (CPC), c = 4· mol/L kao titrans, te metoda standardnog dodatka koja je dala zadovoljavajuće rezultate u otopinama uzoraka komunalnih otpadnih voda. Natrijev dodecilsulfat (NaDS), c = 4· mol/L korišten je kao standardni dodatak. Tijekom određivanja odzivnih karakteristika senzor je pokazao sub-Nernstovski odziv (55,70 mV ± 0,10 po dekadi) u rasponu koncentracija od 2,0· mol/L do 2,0· mol/L za NaDS. Ciljana metoda korištenja DDA-TPB senzora za određivanje anionskih tenzida u uzorcima otpadnih voda bila je direktna potenciometrija, pri čemu su uzorci određivani u natrijevom sulfatu ( ), c = 1· mol/L. Uzorci su određeni i metodom direktne potenciometrije uz standardni dodatak, prilikom čega je kao standardni dodatak korišten NaDS na tri nivoa koncentracija. MBAS metoda je korištena za usporedbu rezultata s onima dobivenima potenciometrijskim titracijama i direktnom potenciometrijom sa i bez standardnog dodatka pri čemu je direktna potenciometija bez standardnog dodatka dala bolje rezultate.Three potentiometric sensors (based on tetraoctadecylammonium-tetraphenylborate, multi-walled carbon nanotubes (MWCNT) functionalized with sulfate group and cetylpyridinium ion and dimethyldioctadecylammonium-tetraphenylborate (DDA-TPB) with addition of carbon nanoparticles, as sensing material) were compared to select the most suitable one for the determination of anionic surfactants in municipal wastewater. Potentiometric sensor based on the DDA-TPB ion pair as an electroactive material and o-nitrophenyloctylether (o-NPOE) as the plasticizer with addition of carbon nanoparticles was selected. Determination of anionic surfactants in municipal wastewater was carried out using three different methods: potentiometric titration, direct potentiometry and standard spectrophotometric method Methylene Blue Active Substances (MBAS). Standard solution of cetylpyridinium chloride (CPC) at concentration of c = 4· mol/L used as titrant and standard addition method, which obtained satisfying results in industrial wastewater samples, were used in potentiometric titrations. Sodium dodecylsulfate (NaDS) at concentration of c = 4· mol/L was used as standard addition. The sensor exhibited a sub-Nernstian response (55,70 ± 0,10 mV/decade of activity) over the range of 2,0· mol/L do 2,0· mol/L for NaDS. The targeted method of using DDA-TPB sensor for determination of anionic surfactants in municipal wastewater samples was direct potentiometry with samples being determined in sodium sulfate ( ), c = 1· mol/L. Samples were also determined using direct potentiometric method with a standard addition, where NaDS was used as added standard at three concentration levels. The MBAS method was used as control for comparison of the results with those obtained using potentiometric titrations and direct potentiometry with and without added standard where direct potentiometry without the standard addition yielded better results
Substitutions of transtition element cations in MOF-5
No full textMetaloorganske mreže su materijali koji su građeni od anorganske(metal) i organske(ligand) jedinice i predstavljaju novu klasu poroznih materijala. Razlikuju se od drugih poroznih materijala zbog svoje velike površine i pora, male gustoće, fleksibilnosti i stabilnosti. U ovom radu sintetiziran je , MOF-5, na dva načina, pri sobnoj temperaturi i u autoklavu. Sintetizirani MOF-5 se koristio za postupak kationske supstitucije prijelaznim elementima. Dobiveni spojevi su karakterizirani pomoću FT-IR spektroskopije, termogravimetrijske i rentgenske analize. Dobiveni rezultati upućuju na realnu mogućnost supstitucije kationa u MOF-5. TG analiza ukazuje na visoku termičku stabilnost MOF-5 i na manji postotak dimetilformamida (DMF) u porama MOF-5, a nakon višestrukog natapanja s diklormetanom (DCM). Supstitucijom kationa u MOF-5 moguće je sintetizirati nove materijale s približno istom strukturom, ali drugačijim svojstvima u odnosu na polazni spoj.Metaloorganic frameworks are materials that are built from inorganic(metal) and organic(ligand) units and represent a new class of porous materials. They differ from other porous materials due to their large surface area and pores, low density, flexibility and stability. In this paper, , MOF-5 is synthesized in two ways, at room temperature and in the autoclave. The synthesized MOF-5 was used for the process of cationic substitution with some transition elements. The prepared crystals were characterized by FT-IR spectroscopy, thermogravimetric and X-ray analysis. The obtained results indicate possibility of cation substitution in MOF-5. TG analysis indicates high thermal stability of MOF-5 and lower percentage of DMF in MOF-5 after multiple soaking with DCM. Using cation substitutions in MOF-5, it is therefore possible to synthesize new materials with approximately the same structure but with different properties in comparison to the starting compound
Biological activity of compounds with oxadiazole core
No full textOksadiazoli su spojevi karakteristični po svojem peteročlanom heterocikličkom prstenu. Zbog širokog spektra bioloških aktivnosti koje pokazuju, ovi spojevi imaju veliki potencijal za otkriće novih medicinski važnih spojeva. Do danas su ispitane razne metode sinteze ovih spojeva, primjerice protokol s karboksilnim kiselinama kao početnim materijalom. Napretkom znanosti utvrĎena su antibakterijska, antiupalna, antituberkulozna, antikancerogena, antiepileptička, anti-HIV, antihelmintička, antidijabetička i mnoga druga učinkovita djelovanja oksadiazola i njihovih derivata. Iako su poznata četiri izomera, svojom se djelotvornošću na području biomedicinskih istraživanja najviše ističe 1,3,4- te 1,2,4-oksadiazol.Oxadiazoles are chemical compounds containing a unique five-membered heterocyclic ring, with great potential for discovery of novel medicinally significant compounds due to their various biological activity. So far, various methods of oxadiazole synthesis have been used, such as protocol with carboxylic acids as starting material. Various research have proven antibacterial, anti-inflammatory, antituberculous, anticancerogenic, antiepileptic, anti-HIV, antihelmintic, antidiabetic and other activities of oxadiazoles and their derivatives. Although there are four oxadiazole isomers, in biomedical research most important ones are 1,3,4- and 1,2,4-oxadiazole
Gases and the gas laws
No full textIako su na prvi pogled jednostavni i po svojoj strukturi i za opisati, plinovi su izuzetno važni. Život na Zemlji se velikim djelom odvija u zraku, čije lokane promjene nazivamo "vremenom". U ovom radu opisani su plinovi, najjednostavniji oblik materije. Opisani su i pokusi koji su doveli do ideje o idealnom plinu i jednadžbi stanja idealnog plina i kako se te ideje lagano mogu proširiti na smjese. Zamišljanje plina kao skupa čestica koje se nasumično gibaju daje objašnjenje zakona idealnog plina. No, taj zakon samo približno vrijedi za realne plinove pa je u ovom radu također opisano zašto se realni plinovi ponašaju drugačije.Although, at first glance they seem simple for their structure and for description, gases are very important. Life on Earth would be unimaginable without air. This undergraduate thesis describes gases, the simplest form of matter. Experiments that led to idea of ideal gas and ideal gas equation and how easily those ideas can be applied on gas mixtures. As we imagine gases as complex of particles which randomly move gives the explanation of the law of ideal gas. However, this law is just about true for real gases, so in this paper it is also described how real gases behave differently
Determination of fat content in hens feed using Soxhlet method
No full textMasti su organski spojevi koji pripadaju široj skupini spojeva zvanim lipidi. Pripadaju skupini spojeva koji su topivi u organskim otapalima. Esteri su glicerola i viših masnih kiselina pa se nazivaju i trigliceridima. Masti utječu na razinu kolesterola u krvi. Zasićene te trans masne kiseline, iako pripadaju nezasićenim masnim kiselinama, povećavaju udio "lošeg" kolesterola, LDL (eng. Low Density Lipoprotein) kolesterol te u isto vrijeme snižavaju udio "dobrog" kolesterola, HDL (eng. High Density Lipoprotein) kolesterol. Mono i polinezasićene masne kiseline povećavaju udio "dobrog" kolesterola te snižavaju udio "lošeg" kolesterola. Soxhlet metoda je uobičajena metoda za određivanje slobodnih masti u uzorcima. Pomoću te metode, ekstrahirana je mast u uzorcima hrane za nesilice te je određena prisutna količina masti. Ekstrakcija je izvođena uz prikladno otapalo, petroleter uz sigurnosne laboratorijske uvjete. Masti su u organizmu veliki izvor energije i imaju veliki energetski doprinos, neophodne su u ishrani kako bi se organizam oprskrbio esencijalnim masnim kiselinama. U ishrani peradi, važno je osigurati hranu bogatu polinezasićenim masnim kiselinama, zbog njihovog korisnog djelovanja na organizam. Cilj ovoga istraživanja je pomoću Soxhlet ekstrakcije odrediti sadržaj masti u različitim uzorcima hrane za nesilice.Fats are organic compounds which belong to a broader group of compounds called lipids. They belong to a group of compounds that are soluble in organic solvents. Fats are, according to the chemical composition, glycerol and higher fatty acids esters and are, therefore, called triglycerides. Fats have a significant effect on the proportion of cholesterol in the blood. Saturated and trans fatty acids, although belonging to nonsaturated fatty acids, increase the share of "bad" cholesterol, LDL (Low Density Lipoprotein) cholesterol, and at the same time decrease the share of "good" cholesterol, HDL (High Density Lipoprotein) cholesterol. Mono and polyunsaturated fatty acids increase the share of "good" cholesterol and decrease the share of "bad" cholesterol. Soxhlet method is common method for determining free fats in samples. Using this method, fat was extracted in the samples of hens feed and the present amount of fat was determined. The extraction was carried out with a suitable solvent: petroleum ether. Fats are a good source of energy in the body and have good energy contribution, fats are essential part of the diet because they provide to the body essential fatty acids. It is important, in nutrition of poultry, to provide food rich in polyunsaturated fatty acids due to their useful effect on the organism. The aim of this study is, to determine the fat content in feed for laying hens. using Soxhlet extraction method
Medications for treating urolithiasis
No full textUrolitijaza ili nefrolitijaza je bolest urinarnog trakta u kojoj dolazi do stvaranja kamenaca u mokraćnom sustavu, a nastaje kao posljedica prekomjernog izlučivanja slabo topljivih tvari mokraćom. Bubrežni kamenci su treća najčešća bolest mokraćnog sustava, nakon uroinfekcije i bolesti prostate. U glavne uzročnike bubrežnih kamenaca ubrajamo hiperkalciuriju, hiperoksaluriju, hiperurikozurija, hipocitraturiju te cistinuriju. Hiperoksalurija nastaje kao posljedica endogene (unutrašnje) hiperprodukcije oksalata. Hiperoksalurija je stanje koje se definira kao povišeno izlučivanje oksalata mokraćom. Odsutnost crijevne bakterije Oxalobacter formigenes u gastrointestinalnom traktu dovodi do povećane apsorpcije oksalata što dovodi do hiperoksalurije. Kao jedan od razloga ne postojanja kolonizacije bakterije Oxalobacter formigenes ističe se dugotrajno uzimanje antibiotske terapije, čime se narušava pH crijevne flore. Osobe s dijagnosticiranom urolitijazom osjećaju vrlo oštru, tupu i neugodnu bol. Oboljelima na raspolaganju stoje dvije skupine lijekova: nesteroidni protuupalni lijekovi (NSPL) (diklofenak, indometacin) te opioidi (hidromorfin, tramadol). Prostaglandini imaju različite funkcije u tijelu, jedna od njih je povećanje osjetljivosti receptora boli na mehaničke i kemijske podražaje. Nesteroidni protuupalni lijekovi smanjuju proizvodnju prostaglandina blokirajući djelovanje enzima ciklooksigenaze (COX) uključenog u njihovo stvaranje. Opioidi prvenstveno svoj analgetski učinak ostvaraju mehanizmom sprječavanja pohrane serotonina i noradrenalina, tvari koje su važne u prijenosu boli te specifičnim vezanjem za opioidne receptore koji su također važni u prijenosu boli.Urolithiasis or nephrolithiasis is a disease of the urinary tract, which is resulting in formation a kidney stone in the urinary tract and it comes about as a consequence of excessive secretion of poorly soluble substances by urine. Kidney stones are the third most common urinary tract disease, after uroinfection and prostate disease. The main causes of kidney stones include hypercalciuria, hyperoxaluria, hyperuricosuria, hypocitraturia and cystinuria. Hyperoxaluria is the result of endogenous (internal) hyperproduction of oxalate. Hyperoxaluria is a condition that is defined as elevated urinary excretion of oxalate. The absence of intestinal bacteria Oxalobacter formigenes in the gastrointestinal tract leads to increased oxalate absorption leading to hyperoxaluria. One of the reasons for the absence of colonization of Oxalobacter formigenes is the prolonged time use of antibiotic therapy, which disrupts the pH of the intestinal flora. People with diagnosed urolithiasis feel very sharp, dull, and unpleasant pain. There are two groups of medications available to the patients: the non-steroidal anti-inflammatory drugs (NSAIDs) (diclofenac, indomethacin) and opioids (hydromorphone, tramadol). Prostaglandins have different functions in the body, one of which is the increase in receptors sensitivity to pain in mechanical and chemical stimuli. Nonsteroidal anti-inflammatory drugs reduce the production of prostaglandins by blocking the activity of the cyclooxygenase enzyme (COX) involved in their production. Opioids primarily have their analgesic effect through the mechanism of preventing storage of serotonin and noradrenaline, substances that are important in pain transfer and specific binding to opioid receptors that are also important in the transmission of pain
Investigation of surfactant-selective electrode response characteristics toward the pseudocationic complexes of barium cation and ethxyated nonionic surfactants
No full textTenzidi su organski spojevi koji smanjuju napetost površine. Sastoje se od dva dijela: polarnog i nepolarnog (hidrofilnog i hidrofobnog). Prema hidrofilnim skupinama koje se nalaze unutar strukture tenzida, tenzide dijelimo u četiri skupine: kationski, anionski, amfolitski i neionski. Metode kojima se najčešće određuju tenzidi su potenciometrijske metode. Metoda koja je korištena u ovome radu je direktna potenciometrija, koja je također i najčešća metoda ispitivanja odziva tenzida. U eksperimentalnom dijelu rada je ispitan odziv tenzidno-selektivne elektrode, koja se sastojala od ionskog para 1,3-didecil-2-metilimidazolijevog tetrafenilborata (DMI-TPB), na pseudokationske komplekse barijevog iona i etoksiliranih neionskih tenzida. Ispitivanje se provelo dodavanjem dvije koncentracije različitih vrsta etoksiliranih neionskih tenzida u otopinu barijeva klorida stalnog volumena i koncentracije. Odzivi elektrode prikazani su grafički te je napravljena usporedba odziva dvije skupine etoksiliranih neionskih tenzida sličnih svojstava.Surfactants are organic compounds that are reducing surface tension. They consists of two parts: polar and non-polar (hydrophilic and hydrophobic). According to the hydrophilic groups found within the structure of surfactants, the surfactants are divided into four groups: cationic, anionic, ampholytic and nonionic. The most frequently used methods for determination of the surfactants are potentiometric methods. The method used in this paper is direct potentiometry, which is also the most common method for surfactant response analysis. In the experimental part of the study, a response of a surfactant-selective electrode consisting of 1,3-didecyl-2-methylimidazolium tetraphenylborate (DMI-TPB) ion pair was tested, to the pseudocationic complexes of barium ions and ethoxylated nonionic surfactants. The test was carried out by adding different types of ethoxylated nonionic surfactants prepared at two concentrations in a solution of constant volume and concentration of barium chloride. The electrode responses were graphically illustrated and a comparison of the response of two groups of ethoxylated nonionic surfactants of similar properties was made
Precipitation of Calcium Oxalate in Artificial Urine
No full textU ovom diplomskom radu provedena su sustavna istraživanja spontanog taloženja kalcijeva oksalata u kompleksnom sustavu umjetnog urina u uvjetima hiperoksalurije. Taložni sustavi su optimizirani kako bi se ujedno imitirali fiziološki i patološki uvjeti (, = 5,0 i = 9,0) u širem koncentracijskom području kalcija (2,0 mmol ≤ ≤ 10,0 mmol ) te koncentracijskom području oksalata (0,6 mmol ≤ ≤ 8,0 mmol ) kako bi se zadovoljio uvjet hiperoksalurije. Glavni cilj istraživanja je ispitivanje utjecaja kompleksnosti i sustava te početne koncentracije reaktanata na taloženje i morfologiju kalcijeva oksalata u patološkim uvjetima. U svim taložnim sustavima umjetnog urina dominantno taloži kalcijev oksalat monohidrat (COM), dok su značajne razlike uočene u sustavu umjetnog urina pri = 9,0 u koncentracijskom području ≥ 6,0 mmol i ≥ 7,5 mmol gdje taloži smjesa COM i kalcijeva oksalata dihidrata (COD). Također su uočene i morfološke razlike između taložnih sustava: u umjetnom urinu talože kristali nepravilnih oblika s tendencijom agregacije, što je posebno izraženo u sustavima više prezasićenosti.In this Thesis, systematic research of spontaneous precipitation of calcium oxalate in the artificial urine system with increased complexity mimicking the conditions of hyperoxaluria was conducted. The precipitation systems have been optimized in order to emulate physiological and pathological conditions (, = 5.0 and = 9.0) over a wide range of initial reactant concentrations of calcium (2.0 mmol ≤ ≤ 10.0 mmol ) and oxalate (0.6 mmol ≤ ≤ 8.0 mmol ) with the aim of establishing hyperoxaluria conditions. The main aim of this research is to investigate the effects of system complexity, initial and reactant concentration on precipitation and morphology of calcium oxalate under pathological conditions. In all precipitation systems, dominant precipitation of calcium oxalate monohydrate (COM) was observed, except in the artificial urine system at = 9.0, in the concentration range ≥ 6.0 mmol and ≥ 7.5 mmol where a mixture of COM and calcium oxalate dihydrate (COD) precipitated. The significant difference in crystal morphology was observed: irregular crystals with pronounced aggregation tendency have precipitated in the artificial urine, particularly in the systems with increased supersaturation