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Neuroprotective and anti-inflammatory effect of apigenin
No full textApigenin je flavonoid koji je široko rasprostranjen u biljkama, voću i povrću te zadnjih
godina često predmet istraživanja zbog pozitivnih učinaka na ljudsko zdravlje. Pokazuje značajne neuroprotektivne učinke zahvaljujući svojoj sposobnosti prolaska kroz krvno-moždanu barijeru i djelovanja unutar središnjeg živčanog sustava. Istraživanja su dokazala njegovo antioksidacijsko, protuupalno, antiapopotsko, antihiperlipidemijsko djelovanje i pozitivno djelovanje na neurotransmisiju. Mehanizam njegovog djelovanja temelji se na smanjenju oksidacijskog stresa jer
djeluje kao izravni hvatač reaktivnih kisikovih vrsta i sudjeluje u regulaciji upalnih signalnih puteva, kao što su MAPK i PI3K/Akt. Aktivacijom Nrf2 puta apigenin jača antioksidacijsku obranu, dok istodobno stabilizira mitohondrijsku funkciju, inhibira apoptozu i potiče mitofagiju. Osim toga, apigenin regulira neurotrofine što djeluje pozitivno na poremećaje neurogeneze. Pozitivni učinci apigenina čine ga potencijalnim kandidatom u prevenciji i terapiji neurodegenerativnih bolesti, kao što su Alzheimerova bolest, Parkinsonova bolest i multipla skleroza.Apigenin is a flavonoid widely distributed in plants, fruits, and vegetables and in recent years it has increasingly become a subject of research due to its beneficial effects on human health. It exhibits significant neuroprotective effects owing to its ability to cross the blood–brain barrier and act within the central nervous system. Studies have confirmed its antioxidant, antiinflammatory, anti-apoptotic, antihyperlipidemic activities and its positive effects on neurotransmission. The mechanism of action is primarily based on the reduction of oxidative stress, functioning as a direct remover of reactive oxygen species and on the regulation of inflammatory signalling pathways such as MAPK and PI3K/Akt. Through activation of the Nrf2 pathway, apigenin enhances antioxidant defences, stabilizes mitochondrial function, inhibits apoptosis, and promotes mitophagy. Moreover, it has been shown to regulate neurotrophins, thereby positively influencing impaired neurogenesis. Due positive properties of apigenin, it is considered as a potential candidate for the prevention and treatment of neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and multiple sclerosis
Potentiometric sensors based on molecularly imprinted polymers
No full textPotenciometrija je jednostavna elektrokemijska metoda koja se primjenjuje već dugi niz godina zbog svoje praktičnosti. Potenciometrijska mjerenja nisu kompleksna iz čega proizlazi njezina široka primjena. Unutar potenciometrije razvijaju se potenciometrijski senzori koji imaju mnoge prednosti ispred ostalih vrsta kemijskih senzora. Razvijeno ih je mnogo, a široko se koriste u medicini, zaštiti okoliša, kontroli kvalitete proizvoda itd. Molekulski tiskani polimeri su ekvivalenti biološkim antitijelima jer svojom strukturom odgovaraju samo određenoj molekuli. Temeljem svog visokog stupnja specifičnosti, pronašli su primjenu u raznim područjima znanosti i svakodnevnim kemijskim analizama. Lako se pripremaju, komercijalno su dostupni i veoma su stabilni. Prilikom njihove sinteze koristi se nekoliko različitih reaktanata, a njihovim pažljivim izborom mogu se kontrolirati mnogobrojna svojstva sintetiziranog polimera. Znanost molekulski tiskanih polimera u zadnjih nekoliko desetljeća doživjela je veliki rast i razvoj, a u novije vrijeme primjenjuju se elektrokemijski senzori temeljeni na molekulski tiskanim polimerima kao što su potenciometrijski senzori. Kombiniranjem selektivnih i lako primjenjivih potenciometrijskih senzora i metode molekulskog tiskanja polimera, dobivaju se spojevi koji mogu odrediti
prisutnost i koncentraciju ispitivane tvari uz vrlo veliku točnost. Njihova primjena je široka, ali svakako zahtijeva daljnji razvoj.Potentiometry is a simple electrochemical method which has been in use for a very long time due to its practicality. Its measurements aren't complex which makes it highly applicable. In line with potentiometry theories, scientists have developed a type of sensors called potentiometric sensors which have many advantages over other types of chemical sensors. Many potentiometric sensors have been synthesized, and they are commonly used in medicine, environmental protection, product quality control etc. Molecularly imprinted polymers are equivalent to biological antibodies because their structure only fits a specific molecule. Based on their high degree of specificity, they have found a wide range of applications in different scientific fields and everyday laboratory analyses. They are easily prepared, commercially available and extremely stable. During their synthesis, a few reagents are used and based on the type of
reagent used the chemical properties of the resulting product can be controled. The science of molecularly imprinted polymers has experienced significant growth and development over the past few decades, and more recently, electrochemical sensors based on molecularly imprinted polymers, such as potentiometric sensors, have been applied. By combining selective and easily applicable potentiometric sensors and the
method of molecular imprinting, the resulting compounds can determine the presence and concentration of the analysed compound with very high accuracy. Their range of application is wide, but still requires further
development
Influence of molecular and crystal structure on the melting point of organic compounds
No full textTalište je jedno od temeljnih fizikalnih svojstava koje pruža uvid u čistoću, stabilnost i međumolekulske sile prisutne u organskim spojevima. Ovaj rad istražuje kako molekulska i kristalna građa utječu na vrijednosti tališta kod organskih spojeva. Objašnjeni su osnovni tipovi međumolekulskih sila, prostorna uređenost molekula i način na koji ovi faktori određuju prijelaz iz krutog u tekuće stanje. Poseban naglasak stavljen je na termodinamičke principe taljenja te ulogu tehnika u određivanju tališta. U radu je objašnjeno kako molekulska simetrija, sposobnost stvaranja vodikovih veza te stupanj kristaliničnosti imaju presudnu ulogu u određivanju tališta organskih spojeva.Melting point is one of the fundamental physical properties that provides insight into the purity, stability, and intermolecular forces present in organic compounds. This paper explores how molecular and crystal structure influence the melting point values of organic substances. The fundamental types of intermolecular forces, the spatial arrangement of molecules, and how these factors govern the transition from the solid to the liquid state are explained in this section. Particular emphasis is placed on the thermodynamic principles of melting and the techniques used to determine the melting point. The thesis discusses how molecular symmetry, the ability to form hydrogen bonds, and degrees of crystallinity play a crucial role in the melting point of organic compounds
Precipitation in synthetic urine
No full textBiomineralizacija obuhvaća složene biokemijske procese u kojima nastaju vrsta mineralizirana tkiva. Patološka biomineralizacija je proces u kojem dolazi do taloženja nepoželjnih minerala u tkivima što može narušiti normalno funkcioniranje organa te organskih sustava. Urolitijaza predstavlja jedan od najzastupljenijih oblika patološke biomineralizacije u modernom društvu, a podrazumijeva stvaranje kamenaca u mokraćnom sustavu. Na njezinu pojavu utječu različiti genetski, nutritivni i ekološki čimbenici te stil života i svakodnevne navike. Najčešći mineral u sastavu mokraćnih kamenaca je kalcijev oksalat. Postoje tri hidratna oblika kalcijevih oksalata: kalcijev oksalat monohidrat (COM),kalcijev oksalat dihidrat (COD) te kalcijev oksalat trihidrat (COT). U ovom završnom radu provedena su istraživanja taložnog sustava umjetnog urina u uvjetima hiperoksalurije. Sintetizirana je stabilna monohidratna faza kalcijeva oksalata čiji su kristali okarakterizirani optičkom mikroskopijom, infracrvenom spektroskopijom te rendgenskom difrakcijom na prahu. Cilj završnog rada bio je istražiti utjecaj različitih koncentracija oksalata na taloženje monohidratne faze kalcijeva oksalata u simuliranim fiziološkim uvjetima.Biomineralization encompasses complex biochemical processes that result in the formation of solid mineralized tissues. Pathological biomineralization is a process in which undesirable minerals are deposited in tissues, potentially disrupting the normal function of organs and organ systems. Urolithiasis is one of the most prevalent forms of pathological biomineralization in modern society and refers to the formation of stones in the urinary system. Its occurrence is influenced by various genetic, nutritional, and environmental factors, as well as lifestyle and daily habits. The most common mineral found in urinary stones is calcium oxalate. There are three hydrated forms of calcium oxalate: calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), and calcium oxalate trihydrate (COT). In this thesis, research was conducted on a precipitation system using artificial urine under hyperoxaluric conditions. A stable monohydrate phase of calcium oxalate was synthesized, and its crystals were characterized by optical microscopy, infrared spectroscopy, and powder X-ray diffraction. This thesis aimed to investigate the influence of different oxalate concentrations on the precipitation of the monohydrate phase of calcium oxalate under simulated physiological conditions
Influence of nutrients on metabolic syndrome
No full textMetabolički sindrom predstavlja skup međusobno povezanih metaboličkih poremećaja, uključujući abdominalnu pretilost, dislipidemiju, hipertenziju i poremećaje glukoze, koji značajno povećavaju rizik od razvoja kardiovaskularnih bolesti i dijabetesa tipa 2. U ovom radu prikazana je uloga nutrijenata u nastanku i razvoju metaboličkog sindroma, a poseban naglasak stavljen je na utjecaj makronutrijenata (ugljikohidrata, masti, proteina i prehrambenih vlakana) te mikronutrijenata (vitamina i minerala) na regulaciju metaboličkih procesa, uz isticanje njihove povezanosti s inzulinskom rezistencijom i oksidacijskim stresom. Osim toga, proučena je i uloga polifenola i drugih bioaktivnih spojeva biljnog podrijetla, koji
zbog svojih antioksidativnih i protuupalnih svojstava smanjuju rizik od komplikacija povezanih s metaboličkim sindromom. Također je naglašen značaj crijevnog mikrobioma u regulaciji metabolizma i njegove interakcije s nutrijentima, što otvara mogućnost za nove terapijske pristupe. Rad ukazuje na važnost uravnotežene prehrane bogate zaštitnim nutrijentima i bioaktivnim spojevima u prevenciji i kontroli metaboličkog sindroma.Metabolic syndrome represents a set of interrelated metabolic disorders, including abdominal obesity, dyslipidemia, hypertension, and glucose abnormalities, which significantly increase the risk of developing cardiovascular disease and type 2 diabetes. This paper presents the role of nutrients in the development and progression of metabolic syndrome, with particular emphasis on the impact of macronutrients (carbohydrates, fats, proteins, and dietary fiber) and micronutrients (vitamins and minerals) on the regulation of metabolic processes, highlighting their association with insulin resistance and oxidative stress. In addition, the role of polyphenols
and other plant-derived bioactive compounds has been examined, as their antioxidant and antiinflammatory properties reduce the risk of complications associated with metabolic syndrome. The importance of the gut microbiome in regulating metabolism and its interactions with nutrients has also been emphasized, opening possibilities for new therapeutic approaches. The paper indicates the importance of a balanced diet rich in protective nutrients and bioactive compounds in the prevention and management of metabolic syndrome
Immunomodulatory imides
No full textImunomodulatorni derivati imida predstavljaju skupinu kemijskih spojeva čiji je razvoj
započeo s talidomidom, a nastavio se sintezom lenalidomida, pomalidomida i novijih modulatora cereblon E3 ligaze. Njihovo djelovanje temelji se na sposobnosti vezanja za protein cereblon, dio E3-ubikvitin ligaznog kompleksa, čime se inducira selektivna degradacija transkripcijskih faktora IKZF1 i IKZF3. Strukturne modifikacije glutarimidne jezgre rezultiraju različitom stabilnošću molekula, farmakokinetikom i selektivnošću prema ciljanim staničnim proteinima. U biokemijskom kontekstu,
ovi spojevi reguliraju ekspresiju imunoloških i antiapoptotskih signalnih puteva te modificiraju mikrookoliš koštane srži. Klinički uspjeh kombinacija s deksametazonom i inhibitorima proteasoma povezan je s njihovom kemijskom prilagodljivošću i farmakodinamičkom sinergijom. Istodobno, razvoj nuspojava poput hematološke toksičnosti i neurotoksičnih efekata ukazuje na potrebu za preciznijim strukturama koje selektivnije djeluju na tumorske stanice. Sve veća primjena biomarkera i molekularnog profiliranja omogućuje prediktivnu primjenu spojeva temeljenu na individualnim biokemijskim parametrima.Immunomodulatory imide derivatives represent a class of synthetic compounds originating from thalidomide and further developed through lenalidomide, pomalidomide, and newer cereblon Er ligase modulating molecules. Their mechanism of action involves binding to cereblon, a component of the E3 ubiquitin ligase complex, triggering selective degradation of transcription factors IKZF1 and IKZF3. Structural modifications of the glutarimide core result in varying molecular stability,
pharmacokinetics, and target specificity. In biochemical terms, these compounds modulate the expression of immune and anti-apoptotic signaling pathways and influence the bone marrow microenvironment. Their clinical effectiveness in combination with dexamethasone and proteasome inhibitors is linked to their chemical adaptability and pharmacodynamic synergy. However, the emergence of hematologic and neurologic toxicities highlights the need for more selective molecular designs. The increasing use of biomarkers and molecular profiling allows predictive application based on individual biochemical parameters
The influence of heat waves on the level of ground-level ozone in urban areas
No full textToplinski valovi, potaknuti klimatskim promjenama, intenziviraju fotokemijske
reakcije dušikovih oksida i hlapljivih organskih spojeva u smjeru nastajanja prizemnog ozona u urbanim sredinama. U ovom radu kvantificirana je veza između toplinskih valova i razine ozona u urbanim sredinama, Osijeku i Rijeci, u razdoblju od 2014. do 2023. godine primjenom analize dnevnog hoda, regresijske analize, analize glavnih komponenti i Fourierove analize. Rezultati potvrđuju porast razine ozona tijekom dana i ljetne maksimume u oba grada. U Osijeku je veza između toplinskih valova i razine ozona jasnije izražena zbog kontinentalnih klimatskih uvjeta, dok Rijeka bilježi složeniji odnos zbog obalne cirkulacije, tlaka zraka i regionalnog transporta. Toplinski valovi značajno pridonose povišenim razinama ozona, a na intenzitet i trajanje epizode visoke razine ozona utječu i lokalni meteorološki čimbenici.Heat waves, driven by climate change, intensify the photochemical reactions of nitrogen oxides and volatile organic compounds leading to the formation of ground-level ozone in urban areas. This study investigates the relationship between heat waves and ozone levels in the cities of Osijek and Rijeka during the period 2014–2023, applying diurnal variation analysis, regression analysis, principal component analysis, and Fourier analysis. The results confirm an increase in ozone levels during the day, with pronounced summer maxima in both cities. In Osijek, the relationship between heat waves and ozone levels is more evident due to continental climatic conditions, while in Rijeka the relationship is more complex, influenced by coastal circulation, air pressure, and regional transport. Heat waves significantly contribute to elevated ozone levels, but the intensity and duration of high-ozone episodes are strongly modulated by local meteorological factors
Assesment of cadmium in biological samples of the inhabitants of Eastern Croatia
No full textRad je proveden s ciljem procjene koncentracija kadmija u biološkim uzorcima (urin, serum, kosa) stanovnika na 9 odabranih lokacija na području istočne Hrvatske. Koncentracije kadmija analizirane su metodom ICP-MS, a rezultati su obrađeni metodama osnovne statistike i klaster analizom. Rasponi vrijednosti medijana koncentracija kadmija iznosili su : urin (0,431-1,127 μg/L), serum (0,065-0,164 μg/L) , kosa (0,009-0,352 μg/g). Rezultati provedene klaster analize nisu ukazali na značajnija grupiranja s obzirom na različitost lokacija (ruralne, suburbane i gradske).The thesis was carried out with the aim of assesing the concentration of cadmium in biological samples (urine, serum, hair) of residents at 9 selected locations in Eastern Croatia. Cadmium concentrations were analysed using the ICP-MS method and the results were processed using basic statistics and cluster analysis. The ranges of median cadmium concentrations were: urine (0,431-1,127 μg/L), serum (0,065-0,164 μg/L), hair (0,009-0,352 μg/g). The results of cluster analysis did not indicate the importance of grouping considering the diversity of locations (rural, suburban and urban)
Cholesterol in meat
No full textKolesterol je sterolna molekula koja ima važnu ulogu u ljudskom organizmu.
Prekomjeran unos kolesterola povezuje se s povećanim rizikom od kardiovaskularnih bolesti. Meso kao prehrambena namirnica životinjskog podrijetla prirodno sadrži kolesterol, čiji sadržaj ovisi o vrsti, podrijetlu i načinu prerade. U ovom radu određivana je koncentracija kolesterola u različitim uzorcima mesa, pilećim prsima, pilećem zabatku, pilećoj jetrici te lososu kako biodredili u kojem uzorku je najveća koncentracija kolesterola. Za određivanje koncentracije koristila se tekućinska kromatografija visoke djelotovornosti s UV-VIS detekcijom. Određena je prosječna koncentracija kolesterola i iznosila je za pileća prsa 62,32 mg/100g, za pileći zabatak 44,93 mg/100g, za pileću jetricu (Proizvođač 1) 141,07 mg/100g, za pileću jetricu (Proizvođač 2) 123,65 mg/100g, te za losos 40,61 mg/100g. Dobiveni rezultati pokazali su da je najmanja koncentracija kolesterola u uzorcima lososa, dok je najveća koncentracija kolesterola u uzorcima pileće jetrice.Cholesterol is a sterol molecule that plays a vital role in the human body. Excessive intake of cholesterol is associated with an increased risk of cardiovascular diseases. Meat, as an animal-based food product, naturally contains cholesterol, and its content depends on the type, origin, and processing method. In this study, the cholesterol content was determined in various meat samples chicken breast, chicken thigh, chicken liver, and salmon, in order to identify which sample contains the highest cholesterol concentration. High-performance liquid chromatography (HPLC) with UV-VIS detection was used for the determination. The average
cholesterol concentrations were as follows: chicken breast 62.32 mg/100 g, chicken thigh 44.93 mg/100 g, chicken liver (Producer 1) 141.07 mg/100 g, chicken liver (Producer 2) 123.65 mg/100 g, and salmon 40.61 mg/100 g. The results showed that the lowest cholesterol concentration was found in salmon samples, while the highest concentration was detected in chicken liver samples
Solid-phase extraction
No full textCilj ovog rada bio je provesti kratki literaturni pregled separacijske tehnike ekstrakcije čvrstom fazom (SPE). U radu je detaljno objašnjen princip ove tehnike, prikazan je razvoj sorbensa te su opisane vrste sorbensa koje se najčešće koriste uz naglasak na njihova kemijska i fizikalna svojstva. Također je obrađen razvoj konfiguracije nosača sorbensa. Predstavljene su i strategije SPE, sam postupak ekstrakcije te kategorije ove metode. Nadalje, analizirana je praktična primjena SPE
u različitim područjima analitičke kemije i industrije, uključujući okolišne, biomedicinske i farmaceutske analize. Ekstrakcija čvrstom fazom predstavlja jednu od najraširenijih metoda pripreme uzoraka, zahvaljujući svojoj sposobnosti optimizacije potrošnje kemikalija, povećanja učinkovitosti analize te postizanja visoke selektivnosti, reproducibilnosti i točnosti dobivenih rezultata.The aim of this paper was a brief literature overview of a separation technique called solid-phase extraction (SPE). The paper explains the principles of this technique, shows the development of the sorbent materials and describes the types of sorbents most often used, with an
emphasis on their chemical and physical properties. The development of sorbent carrier configurations is also discussed. SPE strategies, the extraction procedure itself, and the categories of this method are also presented. Furthermore, the practical applications of SPE in various areas
of analytical chemistry and industry are analyzed, including environmental, biomedical and pharmaceutical analysis. Solid-phase extraction is one of the most widely used sample preparation methods, thanks to its ability to optimize consumption of chemicals, increasing of analysis efficiency, and achieving high selectivity, reproductibility and accuracy of the obtained results