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Study of oxido-reduction properties of L-histidine
No full textU ovom završnom radu su ispitivana oksido-redukcijska svojstva L-histidina u pH području od pH =4 do pH = 10, te stvaranje kompleksa L-histidina sa ionima prijelaznih metala (, , i ) uporabom voltametrijskih metoda (cikličke i diferencijalne pulsne voltametrije) te UV/VIS spektroskopije. Utvrđeno je da je L-histidin elektroaktivan pri pH = 10, u potpuno deprotoniranom obliku te da se oksidacijski produkt L-histidina adsorbira na površinu elektrode od staklastog ugljika. Također je utvrđeno da nastaju kompleksi L-histidina i metalnog iona (, , i ) u omjeru 1:1 u puferu pH = 10.In this final work, the oxido-reduction properties of L-histidine in pH range from pH=4 to pH=10 and formation of the L-histidine complex with transition metals (, , i ) were studied by voltammetric methods (cyclic and differential pulse voltammetry) and UV / VIS spectroscopy. It was found that L-histidine was electroactive at pH = 10, in a completely deprotonated form, and that the oxidative product of L-histidine was adsorbed on the glassy carbon electrode surface. It has also been found that complexes of L-histidine and metal ions (, , i ) were formed in a 1: 1 ratio in a buffer pH = 10
Temporal varioations in concentration of atmospheric pollutanats in the southern part of the Slavonian
No full textOnečišćenje zraka postao je globalni problem koji ne poznaje granice. U ovom radu su prikazani rezultati mjerenja koncentracija atmosferskih polutanata u južnom dijelu Slavonije za 2015.,2016., i 2017. godinu. Sve koncentracije praćenih polutanata mjerene su automatskim analizatorima koji su u vlasništvu Ministarstva zaštite okoliša i prirode, a mjerna postaja smještena je u prigradskoj industrijskoj zoni Slavonskog Broda. Analizom podataka dobiveni su rezultati iz kojih se može pretpostaviti da su koncentracije polutanata u zraku uglavnom antropogenog podrijetla. Koncentracije nekih polutanata se pravilno smanjuju i povećavaju tijekom određenih godišnjih doba ili doba dana što je dokaz fotokemijskih reakcija. U metodičkom dijelu diplomskog rada obrađena je nastavna jedinica "Kisik" za 3. razred gimnazije. Sastoji se od pripreme za nastavni sat koja uključuje plan učeničkog zapisa i radnog listića. Predviđen je frontalni rad s učenicima, zaključno s ponavljanjem nastavne jedinice pomoću predviđenog radnog listića.Air pollution has become a global problem that knows no boundaries. This paper presents the results of measurements of atmospheric pollutants in the southern part of Slavonia for 2015, 2016, and 2017. All concentrations of monitored pollutants were measured by automatic analyzers owned by the Ministry of Environment and Nature, and the local station was located in the suburban industrial area of Slavonski Brod. By analyzing the results obtained, it can be observed that the concentration of pollutants would be in the air of mainly anthropogenic origin. Concentrations of some pollutants properly decrease and increase during certain seasons or days, which is evidence of photochemical reactions. In the methodical part of the diploma thesis, the unit "Oxygen" was analyzed for the 3rd grade of high school. It consists of teacher preparation that includes a plan for student records and a worksheet. Frontal work with students is foreseen, including the repetition of teaching units using the provided worksheet
Chemical equilibrium
No full textU kemijskim reakcijama dolazi do pretvorbe reaktanata u produkte tijekom pregrupacije atoma zbog kidanja postojećih kemijskih veza i stvaranja novih kemijskih veza. Jedna od karakteristika kemijske reakcije je ravnoteža gdje postoje dvije vrlo važne činjenice. Prva je ta da postoje reakcije u kojima se reaktanti transformiraju u produkte i dolazi do zaustavljanja reakcije i takvi procesi se zovu ireverzibilni procesi. Druga činjenica je da postoje reakcije koje se odvijaju u oba smjera i takvi procesi se zovu reverzibilni procesi. Reverzibilna reakcije je moguća samo ako je nastala mala količina produkata te je ujedno i mala brzina povratne reakcije. U jednom trenutku brzine oba procesa će se izjednačiti i uspostaviti će se ravnoteža.In chemical reactions, reactants are converted into products during the regrouping of atoms due to the breaking of existing chemical bonds and the formation of new chemical bonds. One of the characteristics of a chemical reaction is equilibrium where there are two very important facts. The first is that there are reactions in which the reactants are transformed into products and the reaction is stopped and such processes are called irreversible processes. Another fact is that there are reactions that take place in both directions and such processes are called reversible processes. Reversible reactions are only possible if a small amount of products is formed and at the same time a reaction rate is low. At some point, the rate of both processes will become equal and the equilibrium will be reached
Effect of stress on the expression of photosynthetic proteins
No full textU ovom radu je istraživan utjecaj stresa sušom i visokim intenzitetom svjetlosti na ekspresiju D1 podjedinice fotosustava II (PSII), PsbO podjedinice kisik razvijajućeg kompleksa (OEC) i velike podjedinice (LSU) enzima Rubisco u klijancima ječma (Hordeum vulgare L.) kultivara Panonac. Klijanci ječma su izloženi stresu izazvanom sušom u trajanju od 14 dana te visokom intenzitetu svjetlosti u trajanju od 4, odnosno 11 sati u klima komori. Kako bi se odredila količina ispitivanih fotosintetskih proteina, proteini su razdvojeni denaturirajućom elektroforezom u poliakrilamidnom gelu (SDS-PAGE) nakon čega su prenešeni na nitroceluloznu membranu (Western blot) te detektirani specifičnim protutijelima. Izlaganje stresu izazvanom sušom nije doveo do snažnije degradacije sva tri ispitivana fotosintetska proteina. Izlaganje stresu uzrokovanom visokim intenzitetom svjetlosti pokazao je snažniju degradaciju u odnosu na izlaganje suši za sva tri ispitivana proteina. Kraće izlaganje visokom intenzitetu svjetlosti (4h) izazvalo je jaču degradaciju D1 i LSU podjedinice u odnosu na dugotrajnije izlaganje (11h) ovom tipu stresa. Dobiveni rezultati upućuju na to da je izabrana sorta ječma pokazala manju osjetljivost na sušu u odnosu na visoki intenzitet svjetlosti.In this thesis, the effect of stress, trough drought and high light intensity, on the expression of D1 subunit of photosystem II, the PsbO subunit of the oxygen-evolving complex (OEC), and the large subunit (LSU) of the Rubisco enzyme in barley (Hordeum vulgare L.) cultivar Panonac was investigated. e. Barley seedlings were exposed to 14 days of drought stress and to high light intensity stress in the climate chamber in duration of 4 and 11 hours. To determine the amount of examined photosynthetic proteins, denaturing polyacrylamide gel electrophoresis (SDS-PAGE) was used for their separation followed by the transfer to a nitrocellulose membrane (Western blot) and detection with specific antibodies. Exposure to drought induced stress did not result in significant degradation of any of three examined photosynthetic proteins. Exposure to stress caused by high light intensity showed stronger degradation compared to drought exposure in all three proteins. Shorter exposure to high light intensity (4h) caused more degradation of the D1 and LSU subunits when compared to a longer exposure (11h) to this type of stress. The results obtained indicate that the selected cultivar of barley showed a lower sensitivity to drought compared to the high light intensity stress
Synthesis, characterization and metal extraction studies of novel oxa-aza macrocycles
No full textMakrocikličke Schiffove baze jedna su od vrsta markocikličkih molekula koje imaju mogućnost modificiranja čime predstavljaju potencijalne ligande za vezanje različitih metalnih kationa. U ovome radu opisana je sinteza 4 - donorne tetradentatne Schiffove baze korištenjem dialdehida i diamina. Redukcija sintetiziranih makrocikala provedena je pomoću NaBH4 redukcijskog sredstva. Rezultat redukcije su kristalne čvrste tvari mDo4R, mDo5R, mDo6R, mDo7R (mDo4R=1,5-diaza-2,4:7,8:15,16- tribenzo-9,14-dioksa-cikloheptadekan, mDo5R = 1,5-diaza-2,4:7,8:16,17-tribenzo-9,15-dioksa-ciklononadekan, mDo6R = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioksa-ciklononadekan; mDo7R = 1,5-diaza-2,4:7,8:18,19-tribenzo-9,17-dioksa-cikloeikozan) s visokim postotcima iskorištenja. Strukture sintetiziranih spojeva utvrđene su nuklearnom magnetnom rezonancijom (NMR) i IR spektroskopijom (FTIR). Ekstrakcija metalnih kationa provedene je prema poznatoj Pedersonovoj proceduri. Za istraživanje je korišteno 10 metalnih soli pikrata: , , , , , , , , i . Istraživanje ekstrakcije metalnih kationa iz vodenog medija pokazala su da pripravljeni spojevi najbolje ekstrahiraju željezove (III), živine (II) i srebrove (I) katione.Macrocyclic Schiff bases are types of macrocyclic molecules that can be modified to represent potential ligands for binding different types of metals. This paper describes the synthesis of 4 - donor tetradentate macrocyclic Schiff bases using dialdehydes and diamines. The reduction of synthesized macrocycles was performed using a NaBH4 as reducing agent. The results of reduction reactions are crystalline solids mDo4R, mDo5R, mDo6R, mDo7R ( mDo4R=1,5-diaza-2,4:7,8:15,16-tribenzo-9, 14-dioxa-cycloheptadecane, mDo5R = 1,5-diaza-2,4:7,8:16,17-tribenzo-9,15-dioxa-cyclooctadecane, mDo6R = 1,5-diaza-2,4:7,8:17,18-tribenzo-9,16-dioxa-cyclononadecane; mDo7R = 1,5-diaza-2,4:7,8:18,19-tribenzo-9,17-dioxa-cycloeicosane) in high yields. The structures of the synthesized compounds were determined by nuclear magnetic resonance (NMR) and IR spectroscopy (FTIR). Extraction of metal cations was carried out according to the well-known Pederson procedure. For this experiment 10 metal picrates were used: , , , , , , , , i . The results of metal cation extraction indicate that best liquid-liquid extraction is achieved for iron (III), mercury (II) and silver (I) cations
Potentiometric determination of anionic surfactants mixture using sensor with functionalized carbon nanotubes
No full textTenzidi su površinski aktivne tvari koje imaju sposobnost snižavanja površinske napetosti tekućine u kojoj se nalaze. Po kemijskom sastavu, tenzidi su organski spojevi sastavljeni od polarne glave i nepolarnog repa. Ako je tekućina u kojoj se nalaze voda, tada je glava hidrofilna, a rep hidrofoban. U vodenim otopinama, anionski tenzidi disociraju i daju negativno nabijene površinski aktivne organske ione. Tenzidi su obično sastavni dijelovi sredstva za čišćenje i pranje, odnosno to su detergenti. Kod potenciometrijskog određivanja smjese anionskih tenzida korištena je tenzidno selektivna elektroda čija membrana je kao senzorski materijal imala ionski par tetrafenilborata (TPB) i funkcionaliziranih višestjenčanih ugljikovih nanocjevčica (MWCNT, eng. multiwalled carbon nanotubes). Napravljene su potenciometrijske titracije natrijeva dekansulfonata (, c = 4‧ M), natrijeva dodecilsulfonata (, c = 4‧ M) i natrijeva tetradecilsulfonata (, c = 1‧ M) najprije svakog zasebno, a zatim u smjesi. Titracije su izvođene s cetilpiridinijevim kloridom kao kationskim titrantom (CPC, c = 4‧ M).Surfactants are surface active compounds that have the ability to lower the surface tension of the liquid in which they are present. By chemical composition, surfactants are organic compounds composed of polar heads and non-polar tails. If they are contained in water, then the head is hydrophilic and a tail is hydrophobic. Anionic surfactants dissociate in aqueous solutions and form negatively charged surface-active organic ions. Surfactants are usually components of cleaning and washing agents, so they are detergents. For potentiometric determination of anionic surfactants mixture, a surfactant selective electrode with membrane with ionic pair tetraphenylborate (TPB) and functionalized multiwalled carbon nanotubes (MWCNT) as sensor material, was used. Sodium decanesulphonate (, c = 4‧ M), sodium dodecylsulphonate (, c = 4‧ M) and sodium tetradecylsulphonate (, c = 1‧ M) were titrated first separately and then into the mixture. Titrations were performed with cetylpyridinium chloride as cationic titrant (CPC, c = 4‧ M)
Methods for measuring blood glucose concentration
No full textDijabetes je neizlječivi metabolički poremećaj. Razvija se zbog nedostatka inzulina u tijelu, neosjetljivost organizma na inzulin ili oboje. Uzrokuje povišene razine glukoze u krvi što se naziva hiperglikemija ili smanjene koncentracije glukoze koje znamo pod nazivom hipoglikemija. Cilj ovog rada je sažeto i organizirano opisati različite neinvazivne, minimalno invazivne i neinvazivne metode mjerenja razine glukoze u krvi sa njihovim prednostima i nedostacima. Kako bi se razvio pouzdan uređaj za kontinuirano praćenje glukoze u krvi koji je prenosiv, nenametljiv i lak za nošenje na koži, utrošeni su veliki napori u razna znanstvena istraživanja. Trenutno je veliki broj metoda već otkriven i opisan, ali samo ih se nekoliko koristi i u praksi.Diabetes mellitus is an incurable metabolic disorder that results in the human body due to insulin deficiency, insulin resistance or both. It causes elevated blood glucose levels called hyperglycemia or decreased glucose levels known as hypoglycemia. The aim of this study is to describe concise and organised information about different techniques of non-invasive, minimally invasive and invasive continuous blood glucose monitoring with its advantages and limitations. Many research groups have been working to develop wearable sensors for continuous blood glucose monitoring that may become predictable, selective, reliable and acceptable for patient use. In the present, many methods are already discovered and described, but only few are used in practice
Preparation of macrocyclic compounds derived from ortho-vanilin
No full textMakrociklički spojevi pripravljeni s orto-vanilinom vrsta su Schiffovih baza. Nastali su kondenzacijom unaprijed priređenih dialdehida orto-vanilina i p-fenilendiamina. Dialdehidi o-vanilina međusobno su povezani CH2 -skupinama čiji broj može varirati od 4 do 7. Dialdehidi su pripravljeni reakcijom α,ꞷ-dibromalkana koji reagiraju s o-vanilinom pri povišenoj temperaturi u DMF-u kao otapalu. Makrocikličke Schiffove baze nastaju u blago kiselom mediju anhidrida octene kiseline u metanolu kao otapalu. Za nastajanje Schiffovih baza najvažniji su pH uvjeti medija u kojemu ona nastaje. Kako bi kondenzacija dialdehida o-vanilina i p-fenilendiamina u makrocikličku Schiffovu bazu bila uspješna, potrebno je koristi medij čiji se pH iznosi između 3-5 pri povišenoj temperaturi. Kiseli uvjeti reakcije potrebni su za eliminaciju , a istodobno ne smiju biti prekiseli jer bi se amin protonirao, što bi smanjilo njegovu nukleofilnost. Smanjenje nukleofilnosti amina inhibiralo bi prvi stupanj reakcije. Pri nastanku Schiffove baze C=O veza aldehida zamjenjuje se C=N vezom nastalog supstituiranog imina. U završnom radu sintetizirano je šest spojeva, od kojih su tri dialdehidi potrebni za sintezu tri makrocikličke Schiffove baze. Nastali spojevi analizirani su FT-IR spektroskopijom.Macrocycle compounds derived from o-vanillin are compounds that belong to a group called Schiff bases. They are derived by the condensation of dialdehydes precoursors and p-phenylenediamine. Dialdehydes precoirsors are prepared by reaction of o-vanillin with α,ꞷ-dibromalkene on elevated temperatures in DMF as a solvent. The Schiff macrocyclic base is formed in mildly acidic solution of methanol and acetic anhydride. The pH conditions of the medium in which they are formed are crucial for the formation of Schiff bases. For the condensation of the o-vanillin and p-phenylenediamine in macrocyclic Schiff base to be successful it is necessary to use a medium whose pH is in 3-5 on pH scale range and elevated temperature. Acidic reaction conditions are required to eliminate and at the same time they must not be too acidic because the amine would be protonated, which would reduce nucleophilicity on the nitrogen atom. A decrease in the amine nucleophilicity would inhibit the first stage of the reaction. By forming the Schiff base, the C=O bond of the aldehyde is replaced by the C=N of the newly formed substituted imine. In this final paper, six compounds were synthesized- three of which are dialdehydes required for the synthesis three macrocycle Schiff bases. Synthesized products were weight and analyzed by FT-IR spectroscopy
Isolation of metallothioneins using gel filtration
No full textMetalotioneini su proteini male molekulske mase i specifične strukture bogate cisteinima. Prisutni su u mnogim organizmima te su važni za održavanje homeostaze esencijalnih metalnih iona te za detoksifikaciju teških metala. Njihova detekcija i analiza zahtjeva prethodnu izolaciju iz kompleksnih bioloških uzoraka. Gel filtracija je vrsta tekućinske kromatografija kojom se proteini razdvajaju na osnovi veličine te je pogodna za izdvajanje malih proteina, poput metalotioneina, iz kompleksnih bioloških uzoraka. U ovom su radu, metodom gel filtracije uz Sephadex G-50 i G-100, izdvojeni metalotioneini iz homogenata gujavica (Lumbricus terrestris) tretiranih cinkom.Metallothioneins are low molecular weight proteins with specific structure rich in cysteines. They are present in many organisms and are important for maintaining homeostasis of essential metal ions and for detoxification of heavy metals. Their detection and analysis requires prior isolation from complex biological samples. Gel filtration is a type of liquid chromatography that separates proteins based on their size and is suitable for separating small proteins, such as metallothionein, from complex biological samples. In this work, gel filtration with Sephadex G-50 and G-100 was used for isolation of metallothioneins from zinc-treated earth worm (Lumbricus terrestris) homogenates
Electrolytes
No full textElektroliti su tvari koje djeluju kao izvor iona, a karakteristično svojstvo im je sposobnost provođenja električne struje. Otapanjem u otapalu elektroliti disociraju na katione i anione, pri čemu se povećava broj čestica u otopini, te iz navedenog razloga otopine elektrolita imaju izraženija koligativna svojstva u odnosu na otopine neelektrolita. Kemijska promjena izazvana prolazom električne struje naziva se elektroliza. Ovisno o njihovoj sposobnosti disocijacije u otopini, elektrolite dijelimo na jake i slabe. Jaki elektroliti potpuno disociraju na ione, a slabi djelomično što se može izraziti stupnjem disocijacije α. Molarna provodnost tj. sposobnost elektrolitne otopine da provodi struju je određena brojem prisutnih aniona i kationa i njihovim pokretljivostima, a ona je najviša pri beskonačnom razrijeđenju otopine.Electrolytes are substances which are the source of ions and their main characteristic is the ability to conduct electricity. By disolving in a solvent, electrolytes separate into cations and anions thus the number of particles increases. This is the reason why their colligative properties are much higher in comparison with nonelectrolytes. Chemical change caused by conduction of electricity is called electrolysis. Depending on their dissociating ability in a solvent, electrolytes are divided into strong and weak electrolytes, strong being the ones that are fully ionized in solution and weak being the ones that dissociate only partially therefore their behaviour can be expressed by the degree of dissociation α. Molar conductivity is the ability of electrolyte solution to conduct electricity and is determined by the number of present anions and cations and their mobility. Molar conductivity is the highest at the infinite dilution of a solution