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PROTACs for targeted degradation of glycogen synthase kinase 3
No full textCiljana razgradnja proteina (TPD) predstavlja inovativan pristup u istraživanju i razvoju lijekova koji koristi prirodne stanične mehanizme za selektivno uklanjanje patoloških proteina. Posebno je značajna za ciljanje proteina na koje se klasičnim lijekovima malim molekulama ne može učinkovito djelovati. TPD ima velik potencijal u liječenju karcinoma, autoimunih i neurodegenerativnih bolesti.
Jedna od ključnih skupina molekula u TPD-u su kimere koje usmjeravaju ciljanu proteolizu, (engl. Proteolysis Targeting Chimeras, PROTAC-i). Ovaj diplomski rad opisuje sintezu i karakterizaciju PROTAC-a koji ciljaju enzim kinazu glikogen sintaze 3 (GSK3), ključnu kinazu u Alzheimerovoj bolesti.
Opisani PROTAC-i se sastoje od liganda za GSK3 (harmina), liganda za cereblon E3 ligazu (talidomida) i alkiltriazolske poveznice s tri, odnosno četiri ugljikova atoma u alkilnom lancu. U svrhu priprave PROTAC-a bilo je potrebno sintetizirati odgovarajuće prekursore: alkin harmina 2 i azide 3a-b. Alkin 2 dobiven je alkiliranjem harmina propargil-bromidom, dok su azidi 3a-b dobiveni diazo prijenosom iz odgovarajućih N-tert-butiloksikarbonil-monozaštićenih diamina i diazo donora 1H-imidazol-1-sulfonil azid hidroklorida 1. Alkin 2 i azidi 3a-b povezani su preko 1,2,3-triazolskog prstena u jednom reakcijskom koraku Huisgenovom 1,3-dipolarnom cikloadicijom, a nakon uklanjanja zaštitne tert-butiloksikarbonilne (Boc) iz spojeva 4a-b, dobiveni su amini 5a-b. Reakcijom kondenzacije amina 5a-b s talidomidskom kiselinom uz kondenzacijski reagens HATU sintetizirani su PROTAC-i 6a i 6b.
Spojevi su karakterizirani pomoću ¹H i ¹³C NMR, MS i FT-IR spektroskopije. Prema SwissADME analizi, spojevi imaju ograničenu oralnu bioraspoloživost, ne prelaze krvno-moždanu barijeru, djeluju kao inhibitori enzima citokrom P450 te su supstrati P-glikoproteina. Njihova biološka aktivnost bit će ispitana u daljnjim istraživanjima koja prelaze okvire ovog diplomskog rada.Targeted protein degradation (TPD) is an innovative approach in drug discovery and development that harnesses natural cellular mechanisms to selectively eliminate pathological proteins. It is especially important for targeting proteins that cannot be effectively modulated by conventional small-molecule drugs. TPD holds great potential in the treatment of cancer, autoimmune, and neurodegenerative diseases.
One of the major classes of molecules in TPD are proteolysis-targeting chimera (PROTAC). This master’s thesis focuses on the synthesis and characterization of PROTACs targeting glycogen synthase kinase 3 (GSK3), a key kinase implicated in Alzheimer’s disease.
The designed PROTACs consist of a GSK3 ligand (harmine), an E3 ligase ligand (thalidomide), and an alkyltriazole linker containing three or four carbon atoms in the alkyl chain. For the preparation of the target PROTACs, the appropriate precursors were synthesized: harmine alkyne 2 and azides 3a-b. Alkyne 2 was obtained by alkylating harmine with propargyl bromide, while azides 3a-b were synthesized by diazo transfer from the corresponding N-tert-butyloxycarbonyl-monoprotected diamines and the diazo donor 1H-imidazole-1-sulfonyl azide hydrochloride 1. Alkyne 2 and azides 3a-b were connected through a 1,2,3-triazole ring in a single reaction step using Huisgen 1,3-dipolar cycloaddition. After removal of the tert-butyloxycarbonyl (Boc) protecting group from compounds 4a-b, the corresponding amines 5a-b were obtained. Condensation of amines 5a-b with thalidomide acid using the coupling reagent HATU afforded PROTACs 6a and 6b.
The compounds were characterized using ¹H and ¹³C NMR, MS, and FT-IR spectroscopy. According to SwissADME predictions, the compounds exhibit limited oral bioavailability, do not cross the blood-brain barrier, act as cytochrome P450 inhibitors, and are substrates of P-glycoprotein. Their biological activity will be investigated in future studies beyond the scope of this thesis
Investigation of change in water content of swollen donepezil loaded microspheres at simulated nasal conditions
No full textOsjetilni učinci povezani s primjenom lijekova putem nosa važan su aspekt pri razvoju novih oblika lijekova. Prevelika viskoznost gelova ima negativan utjecaj na mehanizam mukocilijarnog čišćenja što može narušiti homeostazu nazalne sluznice i dišnog sustava. Isušivanje i stvaranje filma također su potencijalne mane gelirajućih sustava i mogu uzrokovati iritaciju nosne sluznice i smanjiti adherenciju pacijenata. In vitro ispitivanje gubitka vode iz gela i kroz gel prvi je korak u predviđanju osjetilnih učinaka nakon primjene in situ gelirajućih praškastih sustava za nazalnu primjenu.
Cilj ovog rada bio je ispitati promjenu sadržaja vode pri simuliranim uvjetima nosne šupljine u izbubrenim mikrosferama kao nosačima donepezila, indiciranog u liječenju blage do umjerene Alzheimerove bolesti. Metodom sušenja raspršivanjem pripravljene su mikrosfere koje sadrže: (i) donepezil i kitozan (DK), (ii) donepezil, kitozan i manitol (DKM) te (iii) donepezil, kitozan i laktozu (DKL), i kontrolnim fizičkim smjesama DK mikrosfera s manitolom (DK+M) i laktozom (DK+L). Mikrosfere su uspješno pripravljene sušenjem raspršivanjem, a iskorištenje procesa iznosilo je 14,5 – 60,1 %. Postignuta je uspješnost uklapanja donepezila u rasponu 91,4 – 93,2 % te je sadržaj lijeka iznosio 4,6 – 4,7 %. Bubrenjem svih pripravljenih praškastih uzoraka u umjetnom nosnom fluidu pripravljeni su gelovi za provedbu ispitivanja gubitka vode iz gela i kroz gel, pri simuliranim uvjetima nosne šupljine. Imerzijska ćelija kao nosač gela, pokazala se prikladnom za provedbu predmetnih ispitivanja. Konzistencija gelova koji su u svom sastavu imali laktozu bila je dostatna samo za orijentacijska mjerenja ispitivanih parametara gubitka vode. Za sve gelove inkubirane tijekom 8,5 h pri temperaturi od 34°C i 90% relativne vlage, uočena je linearna ovisnost kumulativnog gubitka mase vode o vremenu: (i) iz gela iznad praznog spremišnog odjeljka imerzijske ćelije, (ii) iz gela iznad spremišnog odjeljka imerzijske ćelije koji sadrži vodu, i (iii) iz spremišnog odjeljka koji sadrži vodu, kroz gel. Najveća brzina isparavanja vode iz gela iznad praznog spremišnog odjeljka imerzijske ćelije (44,3 mg/h) i iznad spremišnog odjeljka koji sadrži vodu (38,5 mg/h) zabilježena je za gel pripravljen bubrenjem DK mikrosfera. Isti gel karakteriziran je i najizraženijim okluzivnim učinkom u usporedbi s drugim ispitivanim gelovima, što upućuje na promjenu strukture konvencionalnog kitozanskog gela uslijed dehidracije. Najveća sposobnost zadržavanja vode DKM gela pripisana je prisustvu manitola te upućuje na najmanju mogućnost isušivanja i stvaranja polimernog filma na nosnoj sluznici te, posljedično, na najmanji rizik od izazivanja iritacije nosne sluznice. Time su DKM mikrosfere procijenjene kao praškasti sustav s najvećim potencijalom za neiritabilnu nazalnu primjenu.Sensory effects associated with nasal drug administration represent an important aspect in the development of innovative drug formulations. Excessive gel viscosity can negatively affect the mucociliary clearance mechanism, potentially disrupting the homeostasis of the nasal mucosa and the respiratory system. Dehydration and film formation are also potential drawbacks of gelling systems, which may cause nasal mucosa irritation and reduce patient adherence. In vitro evaluation of water loss from and through the gel is the first step in predicting the sensory effects following the application of in situ gelling nasal powders.
The aim of this study was to investigate changes in water content under simulated nasal cavity conditions in swollen microspheres used as carriers for donepezil, a drug indicated for the treatment of mild to moderate Alzheimer's disease. Spray dryng method was employed to prepare microspheres containing: (i) donepezil and chitosan (DK), (ii) donepezil, chitosan and mannitol (DKM), and (iii) donepezil, chitosan and lactose (DKL). Additionally, physical mixtures of DK microspheres with mannitol (DK+M) and lactose (DK+L) were used as control samples. The microspheres were successfully prepared with process yields ranging from 14.5% to 60.1%. The entrapment efficiency of donepezil ranged from 91.4% to 93.2%, and drug content ranged from 4.6% to 4.7%. Gell were obtained by swelling of the prepared powder samples in artificial nasal fluid, and subsequently used to evaluate water loss from and through the gels under simulated nasal cavity conditions. The immersion cell used as a gel holder proved to be suitable for conducting the planned investigations. The consistency of gels containing lactose was sufficient only for indicative measurements of water loss parameters. For all gels incubated for 8.5 hours at 34°C and 90% relative humidity, a linear relationship was observed between cumulative water mass loss and time: (i) from the gel above the empty reservoir compartment of the immersion cell, (ii) from the gel above the reservoir compartment containing water, and (iii) from the reservoir compartment containing water, through the gel. The highest evaporation rate from the gel above the empty reservoir compartment (44.3 mg/h) and above the water-containing reservoir (38.5 mg/h) was recorded for the gel prepared by swelling of DK microspheres. This gel also showed the most pronounced occlusive effect compared to other tested gels, indicating structural changes in the conventional chitosan gel due to dehydration. The greatest water retention capacity of the DKM gel was attributed to the presence of mannitol, suggesting the lowest potential for dehydration and polymer film formation at the nasal mucosa and, consequently, the lowest risk of mucosal irritation. Based on these findings, DKM microspheres were recognized as the powder with the greatest potential for non-irritating nasal administration
Analysis of media discourse regarding Islam in the case of news portal in Croatia
No full textOvaj rad analizira medijski diskurs o islamu u Hrvatskoj na primjeru tri hrvatska news portala: 24sata.hr, Index.hr i Večernji.hr. Svrha analize je dobiti uvid u medijsku prezentaciju i sliku islama u Hrvatskoj. Također, naglasak rada je na moći komunikacije odnosno diskursa pri formuliranju stavova pojedinaca. Hipoteza je kako je diskurs o islamu negativnog karaktera s pregršt predrasuda i stereotipa te kako je ovaj diskurs u svoj suštini izrazito rasistički. Istraživanje je provedeno na uzorku od 48 članaka sva tri portala u periodu od 1. siječnja do 30. lipnja 2017. Članci su odabrani upisom termina islam i muslimani u tražilice portala i analizirani kvalitativnom metodom kritičke analize diskursa. Rezultati su u slučaju 24sata.hr i Večernji hr. potvrdili osnovnu hipotezu u cijelosti, dok je u slučaju Index.hr potvrda hipoteze djelomična. Smatram kako razlozi ovakvog prikaza islama leže u geopolitičkim i ekonomskim interesima velesila, sukladno s korištenim teorijama.This paper analyzes media discourse about Islam in Croatia. Three Croatian news portals were analyzed: 24sata.hr, Index.hr and Večernji.hr. The purpose of the anlysis is to get insight into the media presentation of Islam in Croatia. Also one of the main themes of this paper is the power that communication or rather discourse has on the opinions of individuals. The main hypothesis is that the discourse about Islam has a negative character, that many stereotypes and types of prejudice are used and that this discourse is, in its essence, racist. The analysis was conducted on a sample of 48 news articles from all three portals in the period from January 1. until June 30. 2017. The articles are selected by typing Islam or Muslims in the portals search bars and analyzed using critical discourse analysis, a qualitative method. The results confirmed the hypothesis completely in the case of 24sata.hr i Večernji.hr and were partially confirmed in the case of index.hr. It is my opinion that the reason for portraying Islam in this way lay in the geopolitical, strategic and economic interests of superpowers as stated in the theory used
Chemical oxidative polymerization of aniline monomer in the presence of ZnO nanoparticles
No full textNanokompozit polianilin/cinkov oksid (PANI/ZnO) sintetiziran je in situ kemijsko oksidativnom polimerizacijom monomera anilina (ANI) u prisustvu nanočestica cinkovog oksida (ZnO). U radu su istraženi optimalni uvjeti sinteze koja je provedena u vodenoj otopini organskog otapala dietilen glikola (DEG) uz dodatak 2,5 mL, 5,0 mL te 10,0 mL DEG-a te pri različitim vremenima polimerizacije: 15 min, 30 min, 45 min, 60 min. Karakterizacija sintetiziranih nanokompozita provedena je infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), difuznom refleksijskom spektroskopijom (DRS), rendgenskom difrakcijskom analizom (XRD), pretražnom elektronskom mikroskopijom (SEM) te određivanjem elektrovodljivosti. Na temelju rezultata uspješno je provedena sinteza vodljivog PANI/ZnO nanokompozita polimerizacijom anilina u neutralnom mediju uz dodatak DEG-a u uvjetima u kojima je izbjegnuto otapanje nanočestica ZnO. Nadalje, XRD analiza potvrdila je prisutnost nanočestica ZnO u obliku vurcita, dok su FTIR i DRS spektroskopija, kao i elektrovodljivost dokazali postojanje PANI-ja u vodljivom obliku kao zelena emeraldinska sol (PANI-ES). Iz dobivenih rezultata karakterizacije, može se zaključiti da najbolja vodljiva svojstva pokazuju nanokompozitni uzorci PANI/ZnO/5,0 mL DEG – 15 min (κ/S·cm^-1=2,066⋅10^-4) i PANI/ZnO/10,0 mL DEG – 60 min (κ/S·cm^-1=6,227⋅10^-4). Ovaj predstavljeni pristup pokazuje značajan napredak u sprječavanju otapanja nanočestica ZnO osjetljivih na nizak pH tijekom in situ sinteze PANI/ZnO nanokompozita, čime se značajno proširuje područje njegove primjene, pogotovo u fotokatalizi i senzorima.Nanocomposite polyaniline/zinc oxide (PANI/ZnO) was synthesized by in situ chemical oxidative polymerization of aniline monomer (ANI) in the presence of zinc oxide (ZnO) nanoparticles. The paper investigated the optimal conditions of the synthesis, which was carried out in an aqueous solution of the organic solvent diethylene glycol (DEG) with the addition of 2,5 mL, 5,0 mL and 10,0 mL of DEG and at different polymerization times: 15 min, 30 min, 45 min, 60 min. The characterization of the synthesized nanocomposites was carried out by Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and determination of electrical conductivity. Based on the results, a conductive PANI/ZnO nanocomposite was successfully synthesized by polymerization of aniline in a neutral medium with the addition of DEG under conditions in which the dissolution of ZnO nanoparticles was avoided. Furthermore, XRD analysis confirmed the presence of ZnO nanoparticles in the form of wurtzite, while FTIR and DRS spectroscopy, as well as electrical conductivity, proved the existence of PANI in a conductive form as green emeraldine salt (PANI-ES). From the obtained characterization results, it can be concluded that the best conductive properties are shown by nanocomposite samples PANI/ZnO/5,0 mL DEG – 15 min (κ/S·cm^-1=2,066⋅10^-4) and PANI/ZnO/10,0 mL DEG – 60 min (κ/S·cm^-1=6.227⋅10^-4). This presented approach demonstrates significant progress in preventing the dissolution of low pH-sensitive ZnO nanoparticles during the in situ synthesis of PANI/ZnO nanocomposite, thereby significantly expanding its application area, especially in photocatalysis and sensors
A survey of tick species in Sjeverovac, Sunja
No full textKrpelji su mali ektoparazitske hematofagne grinje koji pripadaju redu Ixodida. Poznato je da
su oni uzročnici i prijenosnici uzročnika bolesti. Između ostalog, ti uzročnici uključuju viruse,
bakterije, protiste i metozoe. Iako nisu sve vrste krpelja i svi krpelji unutar vrste vektori,
uvijek postoji potencijalna opasnost za zdravlje u ubodu koji može dovesti do bolesti. Kod
domaćih životinja bolesti koje prenose krpelji mogu uzrokovati velike ekonomske gubitke,
dok kod ljudi velike zdravstvene probleme, uključujući paralizu i smrt. Dakle, prepoznavanje
vrste krpelja može dati uvid u potencijalne uzročnike koji mogu biti preneseni na domaće
životinje, pa čak i ljude.
Cilj ovog istraživanja bio je istražiti raznolikost i morfologiju vrsta krpelja trenutno prisutnih
u Sjeverovcu, Sunja, nudeći pri tome kritički uvid u njihove ekološke uloge i potencijalne
utjecaje na zdravlje. Krpelji su prikupljeni „dragging“ metodom na tri lokacije u Sjeverovcu.
Ukupno je sakupljeno i identificirano četiri vrste krpelja od ukupno 134 jedinke: Ixodes
ricinus (88,06%), Dermacentor marginatus (5,97%), Dermacentor reticulatus (4,48%) i
Haemaphysalis concinna (1,49%). Rezultati ovog istraživanja su dali, početni temeljni
pregled o tome koliko i kojih vrsta krpelja trenutno ima na području Sjeverovca, pridonoseći
pri tome budućim istraživanjima o raznolikosti krpelja, ekologiji i potencijalnim
zdravstvenim posljedicama.Ticks are small ectoparasitic, hematophagous mites that belong to the order Ixodida. They are
known to be causative agents and vectors of various caustive agents of diseases. Among these
causative agents are viruses, bacteria, protista and metozoa. While not every tick species and
every tick within the species are vectors, there is always a potential health risk associated
with a tick bite, which can lead to disease. In domestic animals, tick-borne diseases can cause
significant economical losses, while in humans, they can lead to major health issues,
including paralysis and death. Thus, identifying tick species can give insight into the potential
causative agents that can be transmitted to domestic animals, and even humans.
The aim of this study was to investigate the diversity and morphology of tick species
currently present in Sjeverovac, Sunja, offering critical insights into their ecological roles and
potential health impacts. Ticks were collected using the drag sampling method across three
locations within Sjeverovac. A total of four species out of 134 specimens were collected and
identified: Ixodes ricinus (88.06%), Dermacentor marginatus (5.97%), Dermacentor
reticulatus (4.48%) and Haemaphysalis concinna (1.49%). The results of this research
provided an initial basic overview of the number and species of ticks currently present in the
Sjeverovac area, contributing to future research on tick diversity, ecology and health-related
implications
Analysis of residual stresses in aluminium alloy T-joints made by AC MIG and DC MIG process
No full textZavršni rad obrađen je teorijski i eksperimentalno. U teorijskom dijelu naglasak je na zaostalim naprezanjima kao neizbježnoj pojavi koja se pojavljuje u materijalu kao posljedica zavarivanja. Prikazana su svojstva i karakteristike materijala uzoraka u eksperimentalnom dijelu, te su opisani postupci AC i DC MIG zavarivanja. Objašnjeni su razlozi nastanka zaostalih naprezanja nakon zavarivanja kao i svojstva materijala koja utječu na njih. Prikazana je raspodjela zaostalih naprezanja na zavarenim spojevima uz probleme koje uzrokuju te se predstavljene mjere za smanjenje zaostalih naprezanja. Ukratko su opisane najčešće metode mjerenja zaostalih naprezanja, uz naglasak na metodu rendgenske difrakcije.
U eksperimentalnom dijelu provedeno je mjerenje zaostalih naprezanja metodom rendgenske difrakcije na dvama uzorcima zavarenim AC MIG odnosno DC MIG postupkom. Provedena je analiza rezultata te su dobivene distribucije zaostalih naprezanja shodno literaturi. Usporedbom rezultata AC i DC MIG-a mogu se uočiti različiti iznosi i raspodjela zaostalih naprezanja. Provedeno je elektropoliranje uzoraka te analiza dobivenih rezultata.The topic of this final paper was addressed both theoretically and experimentally. The theoretical part focuses on residual stresses as an inevitable phenomenon occurring in materials after welding. Initially, the materials used for the experimental samples are presented, followed by a description of AC and DC MIG welding processes. The reasons for the formation of residual stresses after welding and the material properties that influence them are explained. The distribution of residual stresses is shown, along with the problems they cause, and measures for their mitigation are discussed. The most common methods for measuring residual stresses are briefly described, with an emphasis on the X-ray diffraction method, its working principle, and basic classification, which was utilized in the experimental part of the work.
In the experimental part, residual stress measurements were performed using the X-ray diffraction method on two samples, one welded using the AC MIG process and the other using the DC MIG process. The results were analyzed, and residual stress distributions were obtained according to the literature. By comparing the results of AC and DC MIG, different amounts and distributions of residual stress can be observed. Electropolishing of the samples was performed and the results obtained were analyzed
Optimization of protein extraction methods for LC-MS/MS analysis: Preliminary analysis of the proteome of the Croatian oak plant (Quercus virgiliana (Ten.) Ten. )
No full textU ovome radu proveli smo analizu metoda ekstrakcije proteina za opisivanje proteoma lista i tkiva modificiranog hrastovom osicom biljke hrvatskog hrasta (drmun, Quercus virgiliana (Ten.) Ten.) pomoću LC-MS spektrometrije masa. Testirana su četiri različita protokola kako bi se odredila najučinkovitija metoda za ekstrakciju i izolaciju proteoma: SDC-FASP, ekstrakcija fenolom u kombinaciji sa SDC-FASP, taloženje TCA/acetonom praćeno ekstrakcijom fenolom i SDC-FASP, te taloženje TCA/acetonom u kombinaciji sa SDC-FASP. Cilj je bio utvrditi najučinkovitiju metodu za izolaciju i pročišćavanje proteina za pripremu uzoraka uz pomoć filtera (engl. filter-assisted sample preparation, FASP). Identifikacija proteina i posttranslacijske modifikacije (PTM) analizirane su korištenjem softvera ProteinPilot™ prema bazi podataka referentnog proteoma Quercus lobata. Iako su izmjereni niski prinosi proteina za sve protokole, taloženje TCA/acetonom praćeno ekstrakcijom fenolom i SDC-FASP dalo je najveći broj identificiranih proteina. Ukupni ionski kromatogrami (engl. total ion chromatograms, TIC) također su potvrdili niske signale peptidnih iona koji ukazuju na niske koncentracije proteina. Usporedna analiza uzoraka lista i tkiva modificiranog hrastovom osicom (engl. gall-wasp) pokazala je različite proteomske profile. Tkiva lista bila su bogata proteinima povezanim s fotosintezom, energetskim metabolizmom i odgovorima na stres, dok tkiva modificiranog hrastovom osicom sadrže proteine povezane s prikupljanjem hranjivih tvari, regulacijom razvoja i imunološkom modulacijom, odražavajući fiziološke učinke modificiranog tkiva na domaćina.In this study, we performed an analysis of protein extraction methods suitable for proteomic experiments of oak leaves and oak gall wasp-modified tissue from Quercus virgiliana using LC-MS-based mass spectrometry. Four extraction protocols were tested for optimal protein isolation: SDC-FASP, phenol extraction combined with SDC-FASP, TCA/acetone precipitation with phenol extraction and SDC-FASP, and a combination of TCA/acetone precipitation and SDC-FASP. The aim was to determine the most effective method for protein isolation and purification for filter-assisted sample preparation (FASP). Protein identification and post-translational modifications (PTMs) were analyzed using ProteinPilot™ with reference to the Quercus lobata proteome. While low protein yields were observed for all protocols, TCA/acetone precipitation followed by phenol extraction and SDC-FASP yielded the highest number of identified proteins. The total ion chromatograms (TIC) also confirmed the low peptide ion signals indicating low protein concentrations. Comparative analysis of leaf and gall wasp-modified tissues revealed different proteomic profiles. The leaf tissues were rich in proteins related to photosynthesis, energy metabolism and stress responses, while gall wasp-modified tissues had proteins related to nutrient acquisition, developmental regulation and immune modulation, reflecting the physiological effects of gall production on the host
Fatigue life of a planetary gearbox with respect to crack initiation at the tooth root
No full textU radu je provedena numerička analiza jednostavnog planetarnog prijenosnika s tri planetarna zupčanika, pri čemu su ispitivani različiti rubni uvjeti kako bi se procijenio njihov utjecaj na raspodjelu naprezanja i zamorni vijek trajanja zuba. Geometrija zupčanika definirana je pomoću softvera KISSsoft, dok je metodom konačnih elemenata (MKE) u programskom paketu Abaqus provedena dvodimenzijska numerička analiza raspodjele naprezanja u korijenu zuba pojedinih zupčanika u prijenosniku. Na temelju dobivenih rezultata, dodatkom FE-Safe izvršena je analiza zamora primjenom principa lokalne deformacije (ε-N metoda), s ciljem određivanja potencijalnog mjesta i vremena do nastanka zamorne pukotine u korijenu zuba.In this work a numerical analysis was conducted of a simple planetary gear set with three planet gears. Different boundary conditions were investigated to assess their influence on stress distribution and tooth fatigue life. The gear geometry was defined using KISSsoft software, while a two-dimensional numerical analysis was conducted of the stress distribution at the tooth root of individual gears within the gear set using the Finite Element Method (FEM) in the Abaqus software package. Based on the obtained results, fatigue analysis was performed using FE-Safe, applying the local strain approach (ε-N method), aiming to determine the potential location and time to crack initiation at the tooth root
Development and Characterization of Novel Ice Cream Enriched with Almond Oil Cake
No full textTijekom proizvodnje hladno prešanog bademovog ulja nastaje nusproizvod poznat kao uljna pogača, koji sve više privlači pozornost zbog mogućnosti primjene u obogaćivanju prehrambenih proizvoda. Zadatak ovog diplomskog rada bio je ispitati svojstva sladoleda u kojem je brašno uljne pogače badema korišteno kao zamjena za 25 %, 50 %, 75 %, te 100 % obranog mlijeka u prahu. Dobiveni uzorci su uspoređeni s kontrolnim uzorkom koji nije sadržavao brašno badema. Određena je titracijska kiselost, porast volumena sladoleda, tvrdoća, parametri boje te svojstva topljenja sladoleda. Dodatak brašna uljne pogače badema u sladoled rezultirao je smanjenjem titracijske kiselosti, porastom vrijednosti tvrdoće te blagim smanjenjem udjela inkorporiranog zraka. Također, uzorci s dodanim brašnom badema pokazali su sporije topljenje i tamniju boju u odnosu na kontrolni uzorak, pri čemu su ostali parametri boje ukazivali na pomak prema crvenim i žutim tonovima. S obzirom na dobivene rezultate, može se zaključiti da se brašno uljne pogače badema može koristiti kao prikladna zamjena mlijeka u prahu u proizvodnji sladoleda, uz potencijalno poboljšanje njegovih fizikalno-kemijskih, ali i nutritivnih svojstava.During the production of cold-pressed almond oil, a by-product known as oil cake is generated. This by-product has been gaining increasing attention due to its potential application in the enrichment of food products. The task of this thesis was to examine the properties of ice cream samples in which almond press cake flour was used as a substitute for 25%, 50%, 75%, and 100% of skim milk powder. The resulting samples were compared with a control sample that did not contain almond flour. The titratable acidity, overrun, hardness, colour, and melting properties were determined. The addition of almond oil cake flour resulted in a decrease in titratable acidity of the ice cream, an increase in hardness values, and a slight reduction in the amount of incorporated air. Furthermore, samples with added almond flour exhibited slower melting rates and darker colouration compared to the control sample, with colour parameters indicating a shift towards red and yellow hues. Based on the obtained results, it can be concluded that almond oil cake flour represents a suitable substitute for skim milk powder in ice cream production, with the potential to improve its physicochemical, and possibly nutritional properties
Parasitofauna of Wild Birds
No full textIako se u Hrvatskoj nalazi 385 vrsta divljih ptica od kojih 285 redovito obitava u
Hrvatskoj, parazitofauna divljih ptica tema je koja nije dovoljno istražena na ovom području.
Ptice, kako u ulozi predatora tako i u ulozi plijena, bitan su dio ekosustava. Nositelji su raznih
parazita, a u ovom istraživanju naglasak je na gastrointestinalnim parazitima koji, iako
normalan nalaz s kojim većina ptica neometano živi, ipak u određenim okolnostima mogu
dovesti do oboljenja pa i uginuća.
Kako bi dobili uvid u prisutnost crijevnih parazita divljih ptica Hrvatske, sakupljeno je
24 uzorka izmeta različitih vrsta ptica koje su zaprimljene u Oporavilište za divlje životinje –
Wildrescue Veterinarskog fakulteta u periodu od 2023. do 2024. godine. Izmet je pripadao
skupinama ptica grabljivica, vrapčarki, golubovki, djetlovki, rodarica te srpokrilki.
Koprološkom pretragom, metodom floatcije izmet je pretražen na prisutnost gastrointestinalnih
parazita Zavodu za parazitologiju i invazijske bolesti s Klinikom.
Izmet 12 ptica nije sadržavao nikakve parazitske elemente dok su u ostalih 12 ptica
uočeni slijedeći paraziti: oociste kokcidija u ćuka, kopca, male ušare, dva kosa te dva goluba;
Capillaria sp. u kopca, male ušare, sove jastrebače, škanjca, kosa, goluba te velikog djetlića;
askaridni tip jajašaca u male ušare i kosa; strongilidni tip jajašaca u male ušare i kosa;
Porrocaecum sp. u kosa.
Kako bi dobili precizniji uvid u prevalenciju parazita kao i raznolikost populacije
parazita koja invadira gastrointestinalni sustav divljih ptica Hrvatske, bilo bi potrebno
uzorkovati izmet većeg broja ptica kroz dulje vremensko razdoblje.Although Croatia is home to 385 species of wild birds, 285 of which are regular
inhabitants, the parasitofauna of wild birds is a topic that has not been sufficiently researched
in this region. Birds, both as predators and prey, are an essential part of the ecosystem. They
are carriers of various parasites, with this study focusing on gastrointestinal parasites which,
although commonly found and often harmless to most birds, can under certain circumstances
lead to disease and even death.
To gain insight into the prevalence and structure of intestinal parasites in wild birds in
Croatia, fecal samples from 24 different bird species, which were admitted to the Wildlife
Rehabilitation Center – WildRescue at the Veterinary Faculty, were collected during the period
of 2023 to 2024. Feces belonged to raptors, passerines, pigeons, woodpeckers, storks, and
swifts. To examine the feces for presence of the gastrointestinal parasites at the Department of
Parasitology and Invasive Diseases with Clinic flotation method was used.
The feces of 12 birds tested negative for parasites while the following parasites were
observed in the other 12 birds: coccidia oocysts in Eurasian scops owl, sparrowhawk, longeared owl, blackbirds, and pigeons; Capillaria sp. in sparrowhawk, long-eared owl, Ural owl,
common buzzard, blackbird, pigeon, and great spotted woodpecker; ascarid-type eggs in longeared owl and blackbird; strongylid-type eggs in long-eared owls and blackbirds; Porrocaecum
sp. in blackbirds.
In order to get more precise insight into the parasite prevalence as well as the diversity
of the parasitic populations that invade the gastrointestinal systems of wild birds in Croatia, it
would be necessary to collect the feces from a larger number of birds over a longer period of
time