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Effects of complex mixtures of plastic nanoparticles on androgen and estrogen receptors
No full textPrekomjerna upotreba plastičnih proizvoda i neprikladno gospodarenje plastičnim otpadom rezultirali su nakupljanjem mikro- i nanočestica plastike (PNP) u okolišu, čime je ugrožen i hranidbeni lanac čovjeka. Interakcija takvih čestica s ljudskim organizmom potvrđena je njihovom detekcijom u mnogim biološkim uzorcima ljudskog porijekla ali njihov učinak na zdravlje, posebice reproduktivno, nije u potpunosti razjašnjen. Zbog mogućnosti adsorpcije različitih kemikalija na površinu PNP izuzetno je važno proučavati utjecaj kompleksnih smjesa kojima je čovjek izložen. Ova doktorska disertacija je imala za cilj odrediti endokrino disruptivno djelovanje PNP ispitivanjem djelovanja pojedinih PNP i smjesa PNP na androgene i estrogene receptore te na proces steroidogeneze. Ispitivanja su provedena korištenjem 3 in vitro modela u skladu s relevantnim regulatornim smjernicama. U istraživanju je korišteno osam vrsta PNP različite veličine i polimernog sastava kako bi se ispitalo utječu li ta svojstva na njihove biološke učinke. Također, ispitan je endokrino-disruptivni učinak PNP u smjesama s oksibenzonom i metilparabenom u svrhu mogućeg otkrivanja sinergističkih i/ili antagonističkih učinaka takvih smjesa. Rezultati pokazuju da učinak PNP na receptore ovisi o vrsti polimera, a učinak je najizraženiji kod nanočestica polipropilena.Excessive use of plastic products and inappropriate management of plastic waste have resulted in the accumulation of plastic micro- and nanoparticles (PNP) in the environment, threatening also the human food chain. The interaction of such particles with the human organism has been confirmed by their detection in many human samples, but their effect on health, especially reproductive, has not been fully clarified. Due to the possibility of adsorption of various chemicals onto the surface of PNP, it is extremely important to study the impact of complex mixtures to which humans are exposed. This doctoral dissertation aimed to determine the endocrine disruptive effect of PNP by examining the interaction of individual PNPs and PNP mixtures with androgen and estrogen receptors and the process of steroidogenesis. Experiments were conducted using 3 in vitro models in accordance with relevant regulatory guidelines. The study used eight types of PNP of different sizes and polymer composition to examine whether these properties affect their biological effects. Also, the endocrine disrupting effect of PNP in mixtures with oxybenzone and methylparaben was evaluated by means of synergistic and/or antagonistic effects of such mixtures. The results show that the effect of PNP depends on the type of polymer and is most pronounced with polypropylene nanoparticles
Epigramatic poetry of Đuro Ferić: interpretation, critical edition and commentary
No full textAutor se u radu bavi trima rukopisnim zbirkama dubrovačkoga erudita, pjesnika, parafrazatora i prevoditelja Đura Ferića (Dubrovnik, 5. VI. 1739. - 13. III. 1820.), jednoga od najplodnijih dubrovačkih pisaca s kraja XVIII. i početka XIX. stoljeća. Donosi se sažeti pregled dosadašnjih istraživanja Ferićeva latinskoga pjesništva te povijesni kontekst u kojem je djelovao i stvarao. Posebno se analiziraju tri rukopisne zbirke njegovih latinskih epigrama koje do sada, osim djelomično, nisu bile posebno istraživane ni interpretirane. Riječ je o sljedećim zbirkama epigrama: Pohvale dubrovačkih pjesnika koji su pisali hrvatskim jezikom (Ragusinorum poetarum qui Illyrica lingua scripserunt elongia Latine exarata), Epigrami o našijencima (Epigrammata de nostratibus) i Moji epigrami (Epigrami miei). Ukupan opseg navedenih zbirki obuhvaća 6 482 stiha koji su transkribirani i čije je kritičko izdanje priređeno u dodatku ovoga rada. Svaka se od navedenih triju zbirki interpretira u kontekstu Ferićeva stvaralaštva i njegova portretiranja Dubrovnika prve polovice XIX. stoljeća. Budući da je kao svećenik i profesor bio kulturno angažiran i u tom kontekstu njegovi su epigrami važni za uvid u recepciju hrvatskih književnika, zatim i za bolje razumijevanje efemernih tema kao i socijalno-psihološkoga profila Ferićevih zbirki per se i njihovu ulogu u dubrovačkoj književnosti, ali i njihovoj anticipaciji hrvatskoga narodnoga preporoda. Temeljem dosadašnjih istraživanja i novostečenih spoznaja nastoji se Ferića prikazati kao ključnu književnu figuru koja čiji latinski opus predstavlja kontinuitet između predromantizma i hrvatskoga narodnoga prepodroda.The author deals with three manuscript collections of the erudite poet, paraphraser and translator Đuro Ferić (Dubrovnik, 5 June 1739 - 13 March 1820), one of the most prolific Dubrovnik writers from the end of the 18th and the beginning of the 19th century. A brief overview of previous research into Ferić's Latin poetry and the historical context in which he worked and created is provided. Three manuscript collections of his Latin epigrams are analyzed in particular, which until now except partially have not been specifically researched or interpreted. These are the following collections if epigrams: Praises of Dubrovnik poets who wrote in Croatian language (Ragusinorum poetarum qui Illyrica linga scripserunt elogia Latine exarata), Epigrams about our citizens (Epigrammata de nostratibus) and My epigrams (Epigrami miei). The total scope of the mentioned collections includes around 6 500 verses that were transcribed and whose critical edition is prepared in the appendix of this work. Each of the mentioned three collections is interpreted in the context of Ferić's creativity and his portrayal of Dubrovnik in the first half of the 19th century. Since he was culturally engaged as a priest and professor, and in this context, his epigrams are important for insight into the reception of Croatian writers, and also for a better understanding of ephemeral topics as well as the social-psychological profile of Ferić's contemporaries. Furthermore, Ferić's language, style and versification are analyzed in the context of Croatian neo-Latin literature. The author places special emphasis on the valorization of Ferić's collections per se and their role in Dubrovnik literature, but also on his anticipation of the Croatian national revival. On the basis of previous research and newly acquired knowledge, we try to present Ferić as a key literary figure whose Latin oeuvre represents the continuity between pre-romanticism and the Croatian national revival.
Ferić's deep connection and work on collecting manuscripts of Croatian poets from 16th-18th centuries resulted with a collection of epigrams under the title Elongia Ragusinorum poetarum qui Illyrica linguia scripserunt in which he mentioned 73 older Croatian poets and 18 prose writers who characterized the mentioned period in the form of praise in verses. The collection consists of total of 854 Latin verses, most of which fall into elgiac couplets, and a smaller part into hendecasyllables. In each epigram, Ferić mentioned the name of the author and the work for which he deserves praise, and if it was about monks, he also mentioned which order the belonged to.
Another manuscript collection of epigrams entitled Epigrammata de nostratibus deals with
humorous anecdotes of Ferić's contemporaries. In 1202 Latin verses and 105 epigrams, which are mostly sarcastic and humorous, he illustrates the incidents of priests, lawyers, merchants and
nobles, and in the commentary he mentions which person it is. Although most of the persons
remain unknown to this day, this collection is of exceptional importance for the social history of Dubrovnik in the first decade of the 19th century.
The third and largest collection entitled Epigrammi miei consists of 541 epigrams in 5
books. The larger epigrams do not have a great literary value, but they point to Ferić's humanist
erudite-eclectic explications. Their mostly trivial content leaves plenty of room for humor and
vivid anecdotes. On the other hand, in some epigrams Ferić shows his reading and education, so
he mentions some writers like John Milton, Jean Racine, Rabelais and others. With these epigrams,Ferić came closest in terms of style and content to the Martial canon, because they are concise, and the writer tries to surprise the reader.
The importance of this research into the life and epigrammatic creativity of Đur Ferić not
only complemented his poetic physiognomy and versification skills, but also showed that in the
manuscript collections of epigrams he established a kind of syncretism of almost disparate starting
points of ancient, medieval and humanistic provenance. The presented corpus of his epigrams
proved to be crucial for delineating his creative profile, which is why he was appreciated by his
contemporaries in Dubrovnik
Preparation and supramolecular chemistry of (thio)urea derivatives of calix[4]arenes – complexation of anions, ion pairs, and heterodimerisation reactions
No full textSintetizirana su tri nova (tio)ureidna derivata kaliks[4]arena te je sustavno istražen njihov afinitet prema brojnim anionima u acetonitrilu pri 25 °C. Kombinacijom ITC, NMR i UV spektroskopije ostvarena je detaljna termodinamička karakterizacija vezanja aniona, uzimajući pritom u obzir mogućnost deprotonacije ureidnih skupina. Primijećeno je nastajanje kompleksa različitih stehiometrija, pri čemu su derivati s većim brojem veznih skupina pokazali veći afinitet za vezanje aniona. U većini slučajeva trend stabilnosti kompleksa slijedio je bazičnost aniona. U slučaju iona H2PO4− i HP2O73−, utvrđen je neobično visok afinitet njihovog vezanja s tioureidnim receptorom. Provedeno je i detaljno istraživanje vezanja ionskih parova (NaCl, NaHSO4 i NaH2PO4) na ureido-amidni kaliks[4]aren u acetonitrilu korištenjem brojnih eksperimentalnih metoda i računalnih simulacija molekulske dinamike te je uočena pozitivna kooperativnost. Termodinamički parametri povezani s popratnim procesima, poput stvaranja ionskih parova i precipitacije soli, određeni su različitim metodama što je omogućilo pouzdano određivanje konstanti stabilnosti ternarnih kompleksa. Reakcije heterodimerizacije između kaliksarena koji sadrže deprotonirane karboksilne skupine i ureidnih derivata kaliks[4]arena, detaljno su istražene pomoću UV spektroskopije, 1H NMR, ITC, DOSY, MS i konduktometrije. Pokazalo se da tetraureidni derivat kaliksarena stvara iznimno stabilne heterodimere s diacetatnim kaliks[4]arenom u acetonitrilu. Potvrđeno je da se doseg reakcije stvaranja heterodimera može kontrolirati promjenom stupnja protonacije karboksilnih skupina, odnosno dodatkom kiseline ili baze. Utvrđeno je i da tioureidni kaliksaren posjeduje izraziti afinitet prema srebrovom kationu, pri čemu nastaje kompleks neuobičajene stehiometrije (3:2, kation:receptor).Three novel (thio)ureido calix[4]arene derivatives were synthesized, and their anion-binding properties towards a series of anions were systematically investigated in acetonitrile at 25 °C. A combination of NMR, ITC, and UV spectroscopy was employed synergistically to provide a comprehensive thermodynamic characterization. Thereby, the possibility of proton transfer from receptor to anion was also considered. Complexes of various stoichiometries were identified, and their stabilities were closely related to the number of binding moieties within the receptor and the basicity of the anions. Rather similar binding affinities were determined for urea and thiourea analogues, except in the cases of H2PO4− and HP2O73− whereby the thiourea receptor formed stronger complexes. Further on, a detailed study of ion-pair binding (NaCl, NaHSO4, and NaH2PO4) by a ureido-amide calix[4]arene host in acetonitrile was conducted using multiple experimental techniques, complemented by molecular dynamics simulations, which revealed positive cooperativity. Thermodynamic parameters related to side processes, such as ion pairing and salt precipitation, were also determined, enabling the reliable determination of ternary complex stability constants. Complex formation between complementary calixarenes containing urea and carboxylate functionalities were examined in detail using UV spectroscopy, 1H NMR, ITC, DOSY, MS, and conductometry. The tetraureido calixarene derivative exhibited the highest affinity, forming heterodimers with diacetate- calix[4]arenes almost quantitatively. Furthermore, the extent of heterodimer formation could be controlled by adjusting the protonation degree of carboxylate groups, i.e. by addition of acid or base. Finally, it was found that a thioureido calixarene interacted with silver cation with a remarkably high affinity, forming an unusual complex stoichiometry (3:2, cation:receptor)
GENETIC VARIABILITY AND PHYLOGENY OF EPSTEIN-BARR VIRUS IN INFECTIOUS MONONUCLEOSIS
No full textVirus Epstein-Barr (EBV) pripada porodici Orthoherpesviridae čiji se genom sastoji od
dvolančane linearne DNA. Temeljem varijabilnosti sekvencija pojedinih gena, EBV se
klasificira u različite tipove, podtipove i varijante. Ciljevi ovog istraživanja bili su odrediti
varijabilnost gena LMP-1, EBNA-1, EBNA-2, BLLF1 i promotora Zp u infektivnoj
mononukleozi (IM), filogenetskom analizom proučiti arhitekturu virusne populacije te
provjeriti mogućnost koinfekcije metodom sekvenciranja nove generacije u uzorcima s više
varijanti gena LMP-1. Najčešća varijanta gena LMP-1 bila je divlji tip, dok su druge varijante
(China1, Med-, North Carolina) i rekombinanti bili rjeđe zastupljeni. Analizom gena EBNA-1
dokazani su prototipovi P-ala i P-thr te novootkriveni polimorfizam Arg594Lys. Analizom
gena EBNA-2 dokazana su oba tipa virusa uz novotkrivenu adiciju Leu212. Najzastupljeniji
podtip gena BLLF1 bio je BLLF1-a s polimorfizmom Q201, dok je najčešća varijanta
promotora Zp bio Zp-P. Rezultati ovog rada pokazali su, po prvi puta, molekularnu raznolikost
EBV-a u IM u ovom geografskom području.Epstein-Barr virus (EBV) belongs to the Orthoherpesviridae family whose genome consists of
double-stranded linear DNA. Based on the variability of individual gene sequences, EBV is
classified into different types, subtypes and variants. The aims of this study were to determine
the variability of LMP-1, EBNA-1, EBNA-2, BLLF1 genes and Zp promoter in infectious
mononucleosis (IM), to study the architecture of the viral population by phylogenetic analysis,
and to check the possibility of co-infection using the new generation sequencing method in
samples with multiple variants of the LMP-1 gene. The most frequent variant of the LMP-1
gene was the wild type, while other variants (China1, Med-, North Carolina) and recombinants
were less frequently represented. The analysis of the EBNA-1 gene showed the presence of
prototypes P-ala and P-thr and the newly discovered polymorphism Arg594Lys. Analysis of
the EBNA-2 gene showed the presence of both viral types as well as newly discovered addition
of Leu212. The most frequent BLLF1 gene subtype was BLLF1-a with the Q201
polymorphism, while the most common variant of the Zp promoter was Zp-P. The results of
this study showed, for the first time, the extent of the molecular diversity of EBV in IM in this
geographical area
Agregacija, paralelna agregacija i koagregacija proteina u kroničnim mentalnim bolestima
No full textChronic mental illnesses (CMIs), including schizophrenia (SZ),
bipolar disorder (BiPD), and major depressive disorder (MDD), present
a substantial burden on individuals and healthcare systems worldwide.
CMIs exhibit complex etiologies involving a mixture of genetic and
environmental factors. While protein aggregation is a well-established
hallmark of neurodegenerative diseases, its role in CMIs remains poorly
understood. Key questions remain unanswered, such as whether
aggregation occurs uniformly across brain regions, whether different
proteins aggregate within the same individuals, what drives this
aggregation, and how it may contribute to behavioral symptoms. This
thesis aims to address these knowledge gaps by investigating the
causes and effects of protein aggregation in CMIs, with a focus on the
potential for co-aggregation of key candidate proteins.
This research utilizes post-mortem human brain samples, in vitro
cell models, and a transgenic Drosophila model. Analysis of human
brain samples revealed distinct patterns of insolubility and aggregation
for CRMP1, DISC1, NPAS3, and TRIOBP-1 across different brain regions
linked to SZ, MDD, and suicide. Notably, these proteins were found to
co-aggregate within the same individuals, including some healthy
controls, suggesting either shared physiological mechanisms or
differential pathological thresholds. The extent and location of
aggregation varied between brain regions and individuals, showing that
it does not follow a consistent pattern based on diagnosis.
Moreover, the link between protein aggregation, genetic
mutation, and environmental susceptibility was investigated using
wild-type and mutant forms of NPAS3 in cell culture experiments. While
previous research showed that mutation alone can cause NPAS3
aggregation, my findings demonstrated that loss of nuclear localization
and potential aggregation can also occur under physiological and stress
conditions, even in the absence of mutation. This suggests that these
changes may be less dependent on genetic alterations than previously
assumed.
Region-specific analysis further revealed that the PAS1 domain
strongly influences NPAS3 localization in cells, promoting its retention
in the cytoplasm rather than the nucleus. This mislocalization may
reduce NPAS3's functional activity and increase its susceptibility to aggregation. Additionally, CRMP1 showed potential for co-aggregation with DISC1 and TRIOBP-1 in cells, echoing findings from human brain
analyses. Additionally, the Drosophila model expressing human DISC1
variants shows potential for revealing behavioral and molecular
alterations. However, the model requires thorough validation due to
lack of expression control.
These findings establish that protein aggregation in CMIs is a
heterogeneous, region-dependent process, with multiple proteins
aggregating within the same individuals. It also provides new evidence
that co-aggregation may be a contributing molecular mechanism in
CMIs. Moreover, it highlights how both genetic and environmental
stressors can influence aggregation. This study is limited by variability
in brain tissue quality, protein aggregation detected in controls, and
reliance on overexpression models in cell culture. Also, the Drosophila
model showed leaky gene expression and requires further validation.
Taken together, these factors highlight the need for improved models
and normalization methods in future research. Nevertheless, the
results from this thesis lay the groundwork for future research into
protein aggregation as a potential biomarker or therapeutic target,
offering novel molecular insights into the pathophysiology of CMIs.Kronične mentalne bolesti (KMB), uključujući shizofreniju (SZ),
bipolarni poremećaj (BiPD) i kliničku depresiju (KD), predstavljaju
značajan teret za pojedince i zdravstvene sustave diljem svijeta. KMB
imaju složenu etiologiju koja uključuje kombinaciju genetskih i
okolišnih čimbenika. Iako je agregacija proteina dobro poznata
značajka neurodegenerativnih bolesti, njezina uloga u KMB još uvijek
nije dovoljno istražena. Ključna pitanja ostaju neodgovorena: događa
li se agregacija ravnomjerno u različitim regijama mozga, agregiraju li
različiti proteini unutar istih pojedinaca, što pokreće agregaciju i kako
ona može pridonijeti razvoju simptoma. Ova disertacija ima za cilj
popuniti te praznine u znanju istraživanjem uzroka i posljedica
agregacije proteina u KMB, s posebnim naglaskom na mogućnost
koagregacije ključnih kandidata proteina.
Opisano istraživanje uključuje analize post-mortem uzoraka
ljudskog mozga, in vitro stanične modele i transgenični model vinske
mušice (Drosophila). Analiza ljudskog moždanog tkiva otkrila je
različite obrasce netopljivosti i agregacije proteina CRMP1, DISC1,
NPAS3 i TRIOBP-1 u različitim regijama mozga povezanim sa SZ, MDD
i
suicidalnim ponašanjem. Analizirani proteini koagregirali unutar
određenih pojedinaca sa dijagnozom i u kontrolnim uzorcima,
upućujući na zajedničke fiziološke mehanizme ili različite patološke
pragove. Opseg i lokalizacija agregacije varirali su među regijama
mozga i pojedincima te agregacija nije bila dosljedna ni specifična za
dijagnozu.
Nadalje, povezanost agregacije proteina, genetskih mutacija i
osjetljivosti na okoliš istražena je pomoću divljeg i mutiranog oblika
proteina NPAS3 u staničnim kulturama. Iako su prethodna istraživanja
pokazala kako sama mutacija može uzrokovati agregaciju NPAS3, moji
rezultati pokazuju kako gubitak nuklearne lokalizacije i potencijalna
agregacija mogu nastupiti i pod fiziološkim i stresnim uvjetima, čak i
bez mutacije. Stoga opisane promjene mogu biti manje ovisne o
genetici nego što se prethodno mislilo. Analiza regija proteina NPAS3
dodatno je pokazala kako PAS1 domena snažno utječe na lokalizaciju
NPAS3 u stanicama, potičući njegovu lokalizaciju u citoplazmi umjesto
u jezgri. Opisana promjena u lokalizaciji može smanjiti funkcionalnu
aktivnost NPAS3 i povećati njegovu sklonost agregaciji. Također,
pokazala sam kako CRMP1 može koagregirati s DISC1 i TRIOBP-1 u stanicama, što je u skladu s rezultatima analize uzoraka ljudskog mozga. Transgenični model vinske mušice koji eksprimira ljudski
DISC1 pokazuje potencijal za otkrivanje bihevioralnih i molekularnih
promjena, ali zahtijeva detaljnu validaciju zbog nedostatka kontrole
ekspresije.
Opisani rezultati potvrđuju heterogenost i specifičnost agregacija
proteina u KMB, pri čemu više proteina može agregirati unutar istih
pojedinaca. Disertacija također nudi nove dokaze kako koagregacija
može biti molekularni mehanizam koji doprinosi razvoju KMB te ističe
utjecaj genetskih i okolišnih čimbenika na agregaciju. Ovo istraživanje
ima ograničenja, uključujući varijabilnost kvalitete tkiva, agregaciju
proteina kod kontrola te prekomjernu ekspresiju proteina u staničnim
kulturama. Također, Drosophila model pokazuje manjak kontrole
ekspresije proteina, zbog čega zahtijeva dodatnu validaciju.
Sveukupno, korišteni modeli i metode zahtjevaju značajnu modifikaciju
u budućim istraživanjima. Unatoč tome, rezultati ovog rada postavljaju
temelje za daljnja istraživanja agregacije proteina kao potencijalnog
biomarkera ili terapijskog cilja, nudeći nove molekularne uvide u
patofiziologiju KMB
Metoda za osiguranje kvalitete oznaka graničnih okvira objekata na slikama utemeljena na strojnom učenju
No full textObject detection is a computer vision technique that enables machines to recognize, identify, and locate objects in an image. The dissertation aims to automate the quality assurance of the object bounding box annotations on images to create a dataset that can be used in object detection solutions in computer vision. In the object detection context, labels are a means of identifying and marking objects in images. They are defined by the object’s name and two points in the image coordinate system. Labels help machine learning models process the content of images and form the basis for their learning. Labels can be derived from different sources with different quality levels. To automate the quality assurance of bounding box labels, a machine learning-based model is proposed to quickly and automatically evaluate the quality of a large set of labels in order to create a reliable dataset of labeled images that can then be used to train more effective object detection models. Building a machine learning-based model, which is a binary classifier, starts with preparing a carefully curated, small yet representative dataset with meticulously labeled examples. Utilizing this dataset, a substantial number of good and bad labels are generated. The classifier is specifically designed to discern between good and bad labels.Detekcija objekata važan je dio računalnog vida koji omogućuje strojevima prepoznavanje, identificiranje i lociranje objekata na slici. Cilj disertacije je automatizirati osiguranje kvalitete oznaka graničnih okvira objekata na slikama kako bi se stvorio skup podataka koji se može koristiti u rješenjima za detekciju objekata u računalnom vidu. U kontekstu detekcije objekata, oznake graničnih okvira su sredstvo za identifikaciju i označavanje objekata na slikama i definirane su imenom objekta i dvjema točkama u koordinatnom sustavu slike. Oznake graničnih okvira slika omogućuju modelima strojnog učenja da razumiju sadržaj slika i čine osnovu za njihovo učenje. Oznake graničnih okvira se mogu prikupiti iz različitih izvora s različitim razinama kvalitete. Kako bi se automatiziralo osiguranje kvalitete oznaka graničnih okvira, predlaže se oblikovanje modela temeljenog na strojnom učenju za brzu i automatsku procjenu kvalitete velikog skupa oznaka kako bi se stvorio pouzdani skup podataka označenih slika koje se zatim mogu koristiti za učenje učinkovitih modela detekcije objekata. Izrada modela temeljenog na strojnom učenju, koji je binarni klasifikator, počinje pripremom pažljivo odabranog, malog, ali reprezentativnog skupa podataka s precizno označenim primjerima. Korištenjem ovog skupa podataka generira se velik broj dobrih i loših oznaka. Klasifikator je posebno dizajniran za razlikovanje dobrih od loših oznaka
Biodegradable hydrogels as drug carriers in the treatment of bone tumors
No full textTradicionalne metode liječenja agresivnih tumora poput osteosarkoma često rezultiraju narušavanjem strukturnog integriteta kosti nakon resekcije tumora, dok popratna kemoterapija često izaziva sistemsku toksičnost, uključujući kardiotoksičnost i imunosupresiju. Takvi problemi naglašavaju potrebu za razvojem ciljanih, višenamjenskih sustava koji ne samo da djeluju kao sustavi za ciljanu dostavu lijekova, već istovremeno potiču obnovu koštanog tkiva kroz osteogena i angiogena svojstva. Biorazgradljivi polimerni sustavi, osobito oni temeljeni na prirodnim polimerima poput kitozana, zbog svoje sličnosti s izvanstaničnom matricom, posjeduju visok stupanj biokompatibilnosti i biorazgradljivosti. Inkapsulacijom kemoterapeutika unutar polimerne matrice kitozana osigurava se zaštita lijeka od prerane razgradnje i postiže ciljano otpuštanje lijeka, što može smanjiti nuspojave i povećati terapijsku učinkovitost tijekom liječenja. Kombinacija sustava za ciljanu dostavu lijekova s inovativnim biokeramičkim materijalima, kao što je hidroksiapatit (HAp), i spojevi bora, poput borne kiseline, ima veliki potencijal u obnovi koštanog tkiva. Kombinacijom HAp biokeramike (potpomaže osteointegraciju i osteogenezu) i borne kiseline (potpomaže angiogenezu) s polimernom matricom kitozana omogućuje se stvaranje kompozitnih biomaterijala koji mogu služiti kao biorazgradljivi sustavi za ciljanu dostavu lijekova uz istovremeno poticanje obnove tkiva. U ovome doktorskom radu pripravljene su bornom kiselinom modificirane kompozitne okosnice na temelju kitozana i HAp-a kao sustavi za ciljanu dostavu kemoterapeutika. Visokoporozne okosnice s različitim udjelom HAp-a i borne kiseline pripravljene su metodom toplinski inducirane fazne separacije praćenom procesom liofilizacije. Identifikacija pripravljenih sustava provedena je rendgenskom difrakcijskom analizom i infracrvenom spektroskopijom s Fourierovom transformacijom koje su potvrdile uspješnu modifikaciju okosnica bornom kiselinom i ugradnju HAp-a u polimernu matricu okosnica. Morfologija okosnica istražena je pretražnom elektronskom mikroskopijom s energijski razlučujućom rendgenskom analizom koje su ukazala na makroporoznu strukturu okosnica s međusobno povezanim porama, te prisutnost kalcija i fosfora na površini kompozitnih okosnica u obliku interaktivnog apatitnog sloja upućujući na bioaktivna svojstva okosnica. Svojstva enzimske razgradnje i kapacitet apsorpcije istraženi su u fiziološkom (fosfatnom) mediju gdje je utvrđena enzimska razgradnja okosnica i visoki kapacitet apsorpcije (do 3000 %) u ovisnosti o pH-vrijednosti, dok su kompozitne okosnice pokazale pad kapaciteta apsorpcije s dodatakom HAp-a u polimernu matricu. Otpuštanje inkapsuliranog lijeka, doksorubicina (DOX), ispitano je u fosfatnom i staničnom mediju. HPLC analizom utvrđeno je pH ovisno otpuštanje DOX-a, dok je UV-VIS analiza otpuštanja DOX-a iz kompozitnih okosnica utvrdila da inkorporacija HAp-a u polimernu matricu nema utjecaj na otpuštanje. Dodatak HAp-u u polimernu matricu nije utjecao na kovalentno umreživanje okosnica genipinom, dok je reološka analiza ukazala na prirodu „jakog“ gela pripravljenih sustava. ICP-MS analizom određeno je otpuštanje iona kalcija i bora uranjanjem u fosfatni medij pri tumorskom (kiselom) i fiziološkom pH. Potvrđeno je pH ovisno otpuštanje iona bora iz modificiranih okosnica i postepeno otpuštanje iona kalcija iz kompozitnih okosnica. Analiza citotoksičnosti kompozitnih okosnica kao nosača lijeka prema HDFa i MG-63 staničnim linijama potvrdila je netoksičnost okosnica bez lijeka dok su okosnice s inkapsuliranim lijekom bile citotoksične prema svim staničnim linijama. Osteogena diferencijacija ljudskih matičnih stanica (hMSC) u stanice osteoblasta na kompozitnim okosnicama potvrđena je detekcijom izvanstaničnih markera osteogene diferencijacije poput kolagena i osteokalcina. Analiza ekspresije vaskularnog endotelnog faktora rasta (engl. vascular endothelial growth factor)(VEGF) kao markera angiogeneze ukazala je na porast ekspresije VEGF-a HDFa stanica uzgojenih s kompozitnim okosnicama s nižim udjelom borne kiseline, dok je kod MG-63 stanica uočen značajan porast ekspresije VEGF-a u kontaktu s kompozitnim okosnicama bez borne kiseline.Traditional treatment methods for aggressive tumours such as osteosarcoma often result in disruption of the bone’s structural integrity following tumour resection, while accompanying chemotherapy frequently induces systemic toxicity, including cardiotoxicity and immunosuppression. These challenges highlight the need for the development of targeted, multifunctional systems that not only serve as platforms for localized drug delivery but also promote bone tissue regeneration through osteogenic and angiogenic properties. Biodegradable polymeric systems, especially those based on natural polymers such as chitosan, exhibit high biocompatibility and biodegradability due to their similarity to the extracellular matrix. Encapsulation of chemotherapeutics within the chitosan matrix protects the drug from premature degradation and enables controlled release, thereby reducing side effects and enhancing therapeutic efficacy. The combination of targeted drug delivery systems with innovative bioceramic materials, such as hydroxyapatite (HAp), and boron compounds, such as boric acid, has great potential in bone tissue regeneration. Integrating HAp bioceramics (supports osteointegration and osteogenesis) and boric acid (supports angiogenesis) with the polymer matrix of chitosan enables the creation of composite biomaterials that can serve as biodegradable systems for the targeted delivery of drugs with simultaneous regenerative properties. In this doctoral work, boric acid-modified composite scaffolds composed of chitosan and HAp were developed as platforms for the targeted delivery of chemotherapeutics. Highly porous scaffolds with varying contents of HAp and boric acid were fabricated using thermally induced phase separation followed by lyophilisation process. The identification of prepared systems was performed by X-ray diffraction and Fourier transformed infrared spectroscopy which confirmed successful boric acid modification and the incorporation HAp into the scaffold polymer matrix. Scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy revealed a macroporous structure with interconnected pores, and the creation of a calcium and phosphate interactive apatite layer on composite scaffold surface when incubated in simulated body fluid (SBF) indicative of bioactive properties of the composite scaffolds. In vitro studies in a physiological phosphate medium demonstrated significant enzymatic degradation and pH-dependent absorption capacity (up to 3000%), while the incorporation of HAp had no significant effect on absorption capacity. Release of the encapsulated drug, doxorubicin (DOX), was evaluated in phosphate buffer and cell culture media. High-performance liquid chromatography demonstrated pH-dependent release of DOX, whereas UV–VIS analysis of DOX release from the composite scaffolds showed that incorporating HAp into the polymer matrix had no effect on the release cadence. Addition of HAp into the polymer matrix did not affect the covalent crosslinking process between chitosan and genipin, while rheological analysis indicated the "strong" gel nature of the prepared composite systems. ICP-MS was used to determine the release of calcium and boron ions by immersing the samples in a phosphate medium at tumor (acidic) and physiological pH. The results confirmed a pH-dependent release of boron ions from the modified scaffolds and a gradual release of calcium ions from the composite scaffolds. Cytotoxicity evaluation of the composite scaffolds as drug carriers toward HDFa and MG-63 cell lines confirmed the non-toxicity of scaffolds without the drug, while drug-loaded scaffolds were cytotoxic against all tested cell lines. The osteogenic differentiation of human mesenchymal stem cells (hMSCs) into osteoblasts on composite scaffolds was confirmed via detection of extracellular markers of osteogenic differentiation such as collagen and osteocalcin. Analysis of the vascular endothelial growth factor (VEGF) expression in HDFa cells indicated increase in VEGF expression when cultured with composite scaffold containing lower amount of boric acid, while MG-63 cells expressed significantly higher quantity of VEGF when cultured with scaffolds without the presence of boric acid
Impact of anthracycline-based chemotherapy on oxidative stress, inflammation and methylation status of RB1 gene in peripheral blood in patients with sarcoma
No full textOvo istraživanje provedeno na kohorti bolesnika sa sarkomom pokazalo je da bolesnici sa sarkomom mogu imati promjenu metilacije gena RB1 u leukocitima periferne krvi te da se viša razina upale i niža razina antioksidansa u perifernoj krvi može povezati s većim tumorskim opterećenjem. Niža razina oksidacijskog stresa i upale te snižena metilacija CpG85 gena RB1 nakon kemoterapije antraciklinima odražava njen pozitivan učinak.This study conducted on a cohort of patients with sarcoma showed that patients with sarcoma may have changes in the methylation of the RB1 gene in peripheral blood leucocytes, and that higher levels of inflammation and lower levels of antioxidants in peripheral blood can be associated with greater tumor burden. The lower levels of oxidative stress and inflammation, along with the reduced methylation of the CpG85 region of the RB1 gene after anthracycline chemotherapy, reflect its positive effect
Modifications of graphene and gallium nitride by swift heavy ions
No full textIstraživanje interakcija između ionskih snopova i čvrste tvari bogato je i rastuće područje u fizici materijala. Ono doprinosi poznavanju temeljnih značajki spomenute interakcije i svojstava materijala u ekstremnim uvjetima zračenja, no, ozračivanje materijala ionskim snopovima također je svestrani alat za modifikaciju i nanostrukturiranje materijala putem uvođenja defekata. Parametri snopa pri ozračivanju, kao što su vrsta iona, energija, doza, kut ozračivanja i nabojno stanje iona mogu se varirati pa se u velikoj mjeri može istraživati i, u konačnici, upravljati efektima ozračivanja.
Korištenje snopova iona visokih energija (~MeV-GeV), koji se često nazivaju brzim teškim ionima, (eng. swift heavy ions, SHI) pruža različite mogućnosti za nanostruktruriranje materijala. Svojom pravocrtnom trajektorijom i dugim dosegom u materijalu mogu stvoriti trajno cilindrično oštećenje, tzv. ionski trag (eng. ion track). Osim mogućnosti za stvaranje nanostruktura u samom volumenu materijala, ionima ove vrste mogu se stvarati jedinstvene strukture i na površini materijala, te u 2D materijalima. Kako bi se procesi proizvodnje ovako nanostrukturiranih defekata mogli predvidjeti i kontrolirati, nužno je razumijevanje procesa nastanka defekata pri ozračivanju. U tu svrhu, u ovoj tezi predstavljene su interakcije ionskih snopova s dva materijala: grafenom i galijevim nitridom.
Prvi dio istraživanja fokusiran je na interakciju dvodimenzionalnog materijala, samostojećeg grafena i grafena na podlozi s ionskim snopovima energija u rasponu 1-23 MeV. Opisana je morfologija defekata u grafenu i povezana je s parametrima ozračivanja. Također je dano objašnjenje podrijetla tih defekata, odnosno određen je doprinos dvaju glavnih kanala depozicije energije snopa u materijal, te je istražen utjecaj podloge. Drugi dio istraživanja tiče se galijevog nitrida koji, kao materijal otporan na efekte zračenja, karakterizira visoki prag za nastanak ionskog traga. Opisani su uvjeti potrebni za uvođenje defekata i nastanak tragova, u prvom koraku snopovima energija u rasponu od 2-900 MeV, a na temelju sekvencijalnog ozračivanja dvama snopovima, opisana su dva oprečna efekta: povećanje i smanjenje broja postojećih defekata, te su također opisani uvjeti u kojima ih je moguće ostvariti. Također je kvantificirana količina defekata prisutna u materijalu po završetku ozračivanja.The interaction of ion beams and solids is a rich and growing field in materials physics. By delving deeper into some of its traits and peculiarities, we can contribute to the current understanding of a material’s behavior under irradiation. Moreover, ion beams are also a versatile tool for materials modification and nanostructuring. Ion beam parameters like ion species, ion charge states, beam energy (velocity), fluence, and angle of irradiation can be controlled, consequently opening the possibility of defects engineering. Using high-energy ion beams in the ~MeV-GeV range, often called swift heavy ions (SHI), offers additional opportunities for materials nanostructuring. With its linear trajectories and long ranges, SHI can create permanent cylindrical damage around the trajectory, called an ion track. Besides the possibility of damage creation in the bulk of the material, SHI can also create unique structures on the materials’ surfaces and in 2D materials. To predict and control the production of nanostructures this way, it is necessary to thoroughly understand the processes of defect creation during ion beam irradiation. For this purpose, in this thesis, we explore the interactions of various ion beams with two materials: graphene and gallium nitride. The first part of our research focuses on the interaction of a 2D material, graphene (suspended and supported) with ion beams in the energy ranges from 1-23 MeV. We describe the morphology of defects and connect it to the beam parameters. We explain the origin of defects by deconvoluting the contribution of the ion beam's two main energy deposition channels to the material and discuss the role of the substrate. The other part of our research presented here pertains to gallium nitride, a bulk material characterized by its radiation hardness, represented by the high energy threshold for the ion track formation. We describe the conditions for the introduction of defects despite this threshold, irradiating this material by ion beams in the energy range of 2-900 MeV. In the second step, we turn to sequential irradiation using two beams, finally reaching two contrary effects: an increase and a decrease in the number of previously introduced defects. We describe the conditions where these effects are reachable, and for all the above cases, we quantify the number of defects that are permanently present in the material after the irradiations
Discrete numerical modelling of reinforced concrete structures by embedded discontinuity approach : doctoral thessis
No full textU ovom radu predstavljen je novi diskretni numerički model s ugrađenim diskontinuitetom za analizu armirano betonskih konstrukcija izloženih statičkom i dinamičkom opterećenju. Unutar diskretnog modela koji se koristi za simulaciju ponašanja betonske konstrukcije zasnovanog na Voronoi poligonima, koji su povezani kohezivnim vezama modeliranima pomoću Timoshenkovih greda, implementirana je armatura koja se postavlja neovisno o postojećoj mreži diskretnih elemenata betona. Modeliranjem međudjelovanja između armature i betona omogućen je prijenos sila između betonskih i armaturnih elementa te simuliranje klizanja armature. Sve materijalne komponente armiranog betona (beton, armaturne šipke i međudjelovanje betona i armature) modelirane su s istim elementima, Timoshenkovim gredama s ugrađenim diskontinuitetom, koje omogućuju opis heterogenosti u materijalu, nelinearno deformiranje i pucanje betona i armature, kao i klizanje i izvlačenje armaturnih šipki. Kako bi se opisalo ponašanje pojedinih komponenti materijala implementirani su modeli ponašanja materijala i to model oštećenja za opisivanje ponašanja krtih i kvazi-krtih materijala poput betona, te model plastičnosti za opisivanje ponašanja čelika i međudjelovanja između armature i betona. Za modele oštećenja i plastičnosti detaljno je prikazan postupak dobivanja lokalnih/unutarnjih varijabli. Za analizu dinamičkog opterećenja razvijen je dinamički model dodavanjem utjecaja inercijalnih sila. Integracija u vremenu se provodi primjenom Newmarkove metode, koristeći sve prethodno razvijene formulacije za statički model. U sklopu dinamičkog modela prikazana je analiza energija u diskontinuitetu za model oštećenja te za model plastičnosti. Validacija novog modela oštećenja-omekšavanja izvršena je na testovima sa statičkim i dinamičkim opterećenjem. Verifikacija i validacija modela za analizu amirano betonske konstrukcije napravljena je za nekoliko statičkih i dinamičkih testova te su dobiveni rezultati uspoređeni s rezultatima dobivenim poznatim analitičkim i numeričkim metodama te dostupnim eksperimentalnim ispitivanjima.In this paper a novel discrete lattice numerical model with embedded discontinuity was presented for modelling of reinforced concrete structures exposed to static and dynamic load. Into discrete lattice model which is used for concrete behaviour and was represented here by Voronoi cells and Timoshenko beams as cohesive links between them, reinforcement bars were implemented and positioned in the concrete domain irrespective of the Voronoi cells. In order to provide force transfer between concrete and reinforcement and to represent bond-slip, the bond between concrete and reinforcement was modelled. All material components of reinforced concrete (concrete, steel bars and bond between concrete and reinforcement) were modelled with the same elements, Timoshenko's beams with embedded discontinuities which enable the representation of heterogeneity of material, nonlinear deformation, cracking of concrete, rupture of reinforcement, bond-slip and pulling out of the reinforcement. In order to describe each material component behaviour, a damage constitutive model was implemented for brittle and quasi-brittle materials like concrete, and a plasticity constitutive model was implemented for steel and bond between concrete and reinforcement. For the damage model and the plasticity model computation of internal variables was presented in detail. For dynamic analysis, dynamic model was developed by adding inertial contributions. Newmark algorithm is used for time integration, with existing formulation for static model. Also, energy analysis for discontinuity for the damage and the plasticity model was presented. Validation of novel softening-damage model was performed for static and dynamic tests. Verification and validation of model for the analysis of reinforced concrete structure was performed for several of static and dynamic tests and results of numerical simulations of this model were compared with results obtained by analytical and numerical methods and results obtained by experiments