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Thermodynamic and structural characterization of cyclopeptide complexes with colorimetric and fluorescent anionic dyes
No full textU ovom su radu ispitana spektroskopska i strukturna svojstva te termodinamička stabilnost kompleksa homociklopentapeptida s kolorimetrijskim i fluorescentnim anionskim bojama u acetonitrilu pomoću spektrofluorimetrijskih i spektrofotometrijskih titracija i simulacija molekulske dinamike. Kao ciklopeptidi korišteni su ciklopentafenilalanin, ciklopentaleucin i derivat ciklopentalizina čije su amino skupine na bočnim ograncima zaštićene BOC skupinama. Kao reprezentativni anioni sulfonatnih fluorescentnih boja korišteni su 8-anilino-1-naftalensulfonska kiselina i alizarin crveno S, a kao reprezentativni anion sulfonatnih kolorimetrijskih boja korišten je metiloranž. Kao reprezentativni anioni karboksilatnih fluorescentnih boja korištene su N-acetilirane aromatske amino kiseline triptofan i fenilalanin. Rezultati upućuju na stvaranje stabilnih kompleksa između ciklopepentaleucina i derivata ciklopentalizina sa sulfonatnim i karboksilatnim fluorescentnim i kolorimetrijskim bojama, dok je u slučaju ciklopentafenilalanina afinitet prema fluorescentnim karboksilatnim bojama nešto viši. Kod nastalih kompleksa ciklopeptida s fluorescentnim sulfonatnim i karboksilatnim bojama u većini slučajeva opažena je značajna razlika u molarnim spektrima kompleksa, dok ta razlika nije uočena kod kompleksa s kolorimetrijskom sulfonatnom bojom. Također, rezultati provedenih MD simulacija u otapalu upućuju na koordinaciju aniona preko amidnih protona ciklopeptida.In this work, spectroscopic and structural properties, as well as thermodynamic stability of homocyclopentapeptide complexes with colorimetric and fluorescent anionic dyes in acetonitrile were examined by means of spectrofluorimetric and spectrophotometric titrations and molecular dynamics simulations. As cyclopeptides, cyclopentaphenylalanine, cyclopentaleucine and cyclopentalysine derivative with BOC protected amino group side chains were used. 8-anilino-1-naftalenesulfonic acid and alizarin red S were used as sulfonic fluorescent dyes representatives, while methyl orange was used as sulfonic colorimetric dye representative. N-acetylated aromatic amino acids tryptophan and phenylalanine were used as carboxylic fluorescent dyes representatives. The results indicate that both of cyclic peptides form stabile complexes with fluorescent and colorimetric sulfonic and carboxylic dyes, while the affinity of cyclopentaphenylalanine towards fluorescent carboxylic dyes is somewhat higher. In most cases a significant difference in molar spectra of fluorescent dye complexes with both peptides were observed. That significant difference was not observed with colorimetric anion dye complexes. Also, the results obtained by MD simulations indicate that the anions are coordinated by the amide protons of the peptide
Detekcija benignih varijanti broja kopija analizom kromosomskih mikročipova u hrvatskoj populaciji
No full textCopy number variants are characterized by losses or gains of DNA sequences in a range from 50 base pairs (pb) up to several megabase (Mb) for each copy. The clinical significance of CNVs is classified according to the guidelines of the American College for Medical Genetics and Genomics. Benign copy number variants are widespread in the general population and have no clinical significance. As part of this research, a retrospective-prospective analysis was conducted based on results for 400 patients referred for diagnostic treatment for various types of neurodevelopmental disorders, in the period from September 2021 to May 2023. As part of the research, a register of benign CNVs of the Croatian population is established. The significantly higher frequency of benign CNVs on chromosome 14 (34.75% of the total number of variants) indicates a possible uniqueness within the Croatian population, while benign variants on chromosomes 13, 18 and 20 are almost absent. The distribution of duplications (72.55%) among 2288 variants is significantly more prevalent than deletions (27.45%). Benign variants encompassing segments or entire genes whose specific alleles are assocaited with different diseases (so called morbid genes) like FCGR3A, ATF6, TFG, NIPA1, TAP2, KANSL1 underscore the existence of non-clinically significant variations in coding and regulatory regions of the human genome. This registry represents an important resource not only for diagnostic purposes but also for future research on genomic variability in the Croatian population, providing a systematic insight into benign CNVs.Varijante broja kopija (CNV) označavaju delecije ili duplikacije DNA veličine od 50 parova baza (bp) do nekoliko megabaza (Mb). Klinički značaj CNV-ova klasificira se prema smjernicama Američkog sveučilišta medicinske genetike i genomike. Benigne varijante broja kopija su raširene u općoj populaciji i nemaju kliničkog značaja. U okviru ovog istraživanja provela se retrospektivno-prospektivna analiza kod 400 pacijenata upućenih na dijagnostičku obradu radi različitih tipova neurorazvojnih poremećaja, u razdoblju od rujna 2021. do svibnja 2023. U sklopu istraživanja napravljen je registar benignih CNV-ova hrvatske populacije. Značajno veća učestalost benignih CNV-ova na kromosomu 14 (34.75% od ukupnog broja varijanti) ukazuje na moguću jedinstvenost unutar hrvatske populacije, dok su benigne varijante na kromosomima 13, 18 i 20 gotovo u potpunosti odsutne. Distribucija duplikacija (72,55%) među 2288 varijanti značajno prevladava u odnosu na delecije (27,45%). Benigne varijante koje sadržavaju dio ili cijele gene, čiji su specifični aleli povezani s različitim bolestima (tzv. morbidni geni) poput FCGR3A, ATF6, TFG, NIPA1, TAP2, KANSL1, pokazuju da unutar ljudskog genoma postoje različite varijante u kodirajućim i regulacijskim regijama koje nemaju klinički značaj. Ovaj registar predstavlja važan resurs ne samo za dijagnostičke svrhe već i za buduća istraživanja genomske varijabilnosti u hrvatskoj populaciji, pružajući povezan i sustavan uvid u benigne CNV-ove
Load capacity analysis of cylindrical asymmetric gears
No full textOdabirom različitih kutova nagiba profila osnovne ozubnice dobiva se geometrija ozubljenja koju nazivamo asimetričnom. Nosivosti korijena i boka zuba nedvojbeno ovise o toj geometriji. U ovome radu opisana je osnovna geometrija vezana uz asimetrično ozubljenje, opisani su postupci proračunavanja nosivosti korijena i boka asimetričnog zuba zupčanika te je izvršena analiza nosivosti asimetričnog ozubljenja u ovisnosti o promjeni pojedinih parametara geometrije. Postupak proračunavanja nosivosti korijena asimetričnog ozubljenja preuzet je od Langheinricha koji je primjenom metode konačnih elemenata modificirao postojeću normu ISO 6336-3 te u proračun uveo nove faktore kako bi korigirao ovisnost geometrije asimetričnog zuba. Postupak proračunavanja nosivosti korijena ostaje isti te se vrši prema normi ISO 6336-2. Analiza nosivosti provedena je u programskom paketu KISSsoft te je provedena za različite kutove nagiba aktivnog boka, kutove nagiba neaktivnog boka, polumjere zaobljenja korijena osnovne ozubnice te module. Konačni rezultati analize pokazali su da se promjenom geometrije asimetričnog ozubljenja mogu postići značajne promjene u nosivosti korijena i boka, indicirajući na superiornost geometrije asimetričnog ozubljenja.By choosing the different pressure angles of a basic rack we get gearing geometry that is called asymmetrical gearing. Load capacity of a tooth root and a flank highly depend on mentioned geometry. This thesis describes the basic geometry of an asymmetric gearing, calculation of load capacity for tooth root and a flank of an asymmetric gear and an analysis of load capacity for asymmetric gearing depending on the change of given geometry parameters. Calculation of load capacity for tooth root of an asymmetric gear was taken from Langheinrich, who used finite element analysis method to modify the existing ISO 6336-3 standard by introducing new factors for correcting an influence of a pressure angle change. Calculation of flank load capacity stays the same and is calculated using the ISO 6336-2 standard. Load capacity analysis in this thesis was made using software package KISSsoft and was carried for different pressure angles on drive side, pressure angles on coast side, tooth root fillets of a basic rack and moduli. Final results of an analysis showed great changes in both load capacity of tooth flank and tooth root for different geometry settings, indicating the superiority of an asymmetric gearing
The expression of IL1B and CXCR4 genes in EGFR-positive non-small cell lung cancer
No full textKarcinom pluća vodeći je uzrok smrtnosti povezane s tumorima u svijetu. Ovisno o molekularnim
karakteristikama, karcinom pluća dijeli se na podtipove, a njihova precizna karakterizacija nužna
je za primjenu ciljane, što efikasnije terapije. Za jedan od podtipova karcinoma pluća nemalih
stanica, adenokarcinom, osobito je važna mutacija gena EGFR. Vodeća mutacija u genu za receptor
epidermnog faktora rasta definira podtip karcinoma pluća, a povezana je i s promjenama u
tumorskom mikrookolišu. Interakcija stanica tumorskog mikrookoliša putem brojnih signalnih
molekula ključna je za imunosni odgovor organizma na tumor, a uključena je i u odgovor na
terapiju. U ovom radu istražena je ekspresija interleukina-1β i kemokina CXCR4 koji su dio
imunosnog odgovora kod pacijenata s karcinomom pluća. Kako bi se utvrdila potencijalna
povezanost između ekspresije gena IL1B, koji kodira proupalni citokin interleukin-1β, i gena
CXCR4, koji kodira kemokinski receptor 4, s mutacijom u genu EGFR, izolirana je RNA iz uzoraka
karcinoma pluća nemalih stanica koji ima mutaciju gena EGFR, provedena je reverzna
transkripcija te je lančanom reakcijom polimerazom u stvarnom vremenu utvrđena razina
ekspresije tih dvaju gena. Dobiveni podaci uspoređeni su s podacima za karcinom pluća nemalih
stanica koji nema mutaciju gena EGFR i pokazano je da je ekspresija gena IL1B i CXCR4 statistički
značajno niža kod tumora s mutacijom.Lung cancer is the leading cause of cancer-related mortality worldwide. There are several subtypes
of lung cancer, depending on molecular characteristics, which must be precisely characterized to
apply targeted, most efficient possible therapy. Adenocarcinoma, one of the subtypes of non-small
cell lung cancer, is often characterized by the mutation of the EGFR gene. This driver mutation in
the epidermal growth factor not only defines a specific subtype of cancer but is also associated with
specific changes in the tumor microenvironment. Cells of the tumor microenvironment
communicate through an intricate net of signaling molecules which is crucial for the body’s
immune response to the tumor and the tumor’s response to therapy. In this thesis, the expression
of interleukin 1β and chemokine CXCR4, both part of the immune response, is investigated. To
determine a potential association between their expression and the EGFR gene mutation, RNA was
isolated from non-small cell lung cancer samples, reversely transcribed into cDNA with which
polymerase chain reaction in real time was performed. Expression levels of these genes were also
compared to the data for non-small cell lung cancer lacking the EGFR mutation. It was shown that
the expression of the IL1B and CXCR4 genes is significantly lower in the tumors with the EGFR
gene mutation
Spectral profiles of unifloral types of honey from the Republic of Croatia
No full textBudući da med potječe od različitih biljnih vrsta, složen je proizvod raznolikog sastava. Stoga su klasične analitičke metode za određivanje botaničkog podrijetla meda zahtjevne te se u tu svrhu sve više primjenjuju i instrumentalne analitičke metode od kojih se posebno ističe infracrvena (IR) spektroskopija. Cilj je ovog rada bio utvrditi specifične spektralne profile uniflornih vrsta meda s područja Republike Hrvatske te izraditi zbirku IR spektara istih temeljem njihovih karakterističnih apsorpcijskih vrpci. Uz navedeno, cilj je istraživanja bio utvrditi korelaciju između spektralnih podataka i fizikalno-kemijskih parametara meda (udio vode, električna provodnost i pH vrijednost). Prikupljeno je ukupno 226 uzoraka meda s područja 6 županija RH koji su obuhvaćali 23 vrste uniflornog meda. Analiza fizikalno kemijskih parametara provedena je klasičnim analitičkim metodama. IR spektri meda su snimljeni FTIR- spektroskopijom s ATR tehnikom snimanja spektara. Rezultati su pokazali kako su fizikalno- kemijski parametri svih analiziranih uzoraka meda u skladu s međunarodno propisanim kriterijima. FTIR-ATR spektri analiziranih uzoraka meda pokazali su slične integralne spektralne značajke karakterističan za med, ali su se temeljem sličnosti apsorpcijskih vrpci fruktoze, glukoze i saharoze istaknula tri karakteristična spektralna profila. Jednostavnom linearnom regresijom nije utvrđena korelacija između fizikalno-kemijskih parametara i spektralnih podataka što ukazuje na potrebu primjene kemometrijskog modeliranja s ciljem utvrđivanja njihove korelacijske povezanosti.Since honey originates from different plant species, it is a complex product with a diverse composition. Therefore, classical analytical methods for determining the botanical origin of honey are complex, and instrumental analytical methods are increasingly being used for this purpose, of which infrared (IR) spectroscopy stands out. The aim of this study was to determine the specific spectral profiles of unifloral types of honey from the Republic of Croatia and to create a collection of IR spectra based on their characteristic absorption bands. In addition to the above, the aim of this research was to determine the correlation between the spectral data and physicochemical parameters of honey (water content, electrical conductivity and pH value). In total 226 honey samples were collected from 6 counties of the Republic of Croatia, including 23 types of unifloral honey types. Physiochemical analyses were carried out using classical analytical methods. Honey IR spectra were recorded using the FTIR spectroscopy coupled with ATR recording technique. Results have revealed that the physiochemical properties of analysed honey samples were in accordance with internationally prescribed criteria. FTIR-ATR spectra of analysed honey samples showed similar integral spectral features characteristic for honey, but based on the similarity of the absorption bands of fructose, glucose and sucrose, three characteristic spectral profiles were determined. Simple linear regression did not show a correlation between the physicochemical parameters and spectral data which indicates a need to apply chemometric modeling aiming to determine their correlation
The influence of inhibitors on the protective properties of biological acrylate coating
No full textU skladu s rastućom potražnjom za ekološki prihvatljivim alternativama u industriji premaza,
razvijen je vodorazrjedivi akrilatni premaz na bioosnovi za direktnu zaštitu metalnih površina.
U radu su evaluirane karakteristike razvijenog bio-premaza uspoređujući tri vrste inhibitora
korozije: hlapljivi inhibitor korozije, inhibitor korozije na bazi metalnog kompleksa te
inhibitor korozije na bazi aminokarboksilata. U eksperimentalnom dijelu određena su
fizikalna i mehanička svojstva ispitnih premaza s fokusom na usporedbu zaštitnih svojstava
inhibitora korozije koristeći ispitivanje u vlažnoj i slanoj komori, te elektrokemijsku
impedancijsku spektroskopiju (EIS). Rezultati ovog rada doprinose kontinuiranim naporima u
razvoju održivih premaza s poboljšanim svojstvima zaštite od korozije te pruža vrijedne
informacije o performansama ekoloških alternativa u usporedbi s tradicionalnim premazima.In response to the growing demand for environmentally friendly alternatives in the coating
industry, a water-dilutable bio-based acrylic coating for DTM protection has been developed.
The characteristics of the developed bio-coating were evaluated by comparing three types of
corrosion inhibitors: volatile corrosion inhibitor, metal complex-based corrosion inhibitor,
and amino carboxylate-based corrosion inhibitor. In the experimental section, the physical
and mechanical properties of the test samples were determined, with a focus on comparing the
protective properties of corrosion inhibitors using humidity testing, salt spray testing, and
electrochemical impedance spectroscopy (EIS). The results of this study contribute to ongoing
efforts in the development of sustainable coatings with improved corrosion protection
properties and provide valuable information on the performance of environmental alternatives
compared to traditional coatings
Distribution of organic pollutants in the air, total deposited matter, and soil in the city of Zagreb and its surroundings
No full textOnečišćenje zraka je globalni problem koji uzrokuje brojne posljedice po ljudsko zdravlje i okoliš. Dokazano štetne učinke imaju lebdeće čestice u zraku, osobito one ekvivalentnog aerodinamičkog promjera manjeg od 10 μm (PM10) i 2,5 μm (PM2,5), koje mogu u svom sastavu sadržavati brojne toksične tvari. Policiklički aromatski ugljikovodici (PAU) su spojevi od posebnog interesa zbog svog štetnog kancerogenog djelovanja, dok poliklorirani bifenili (PCB) i organoklorovi pesticidi (OCP) pripadaju grupi postojanih organskih onečišćujućih tvari koje karakterizira postojanost, bioakumulacija i toksičnost. Atmosfersko taloženje, uključujući suho i mokro taloženje, koje je ključno za uklanjanje onečišćujućih tvari iz zraka, može imati negativne učinke na ekosustave i posredno na ljudsko zdravlje. Štetni organski spojevi dospijevaju u tlo putem prirodnih procesa taloženja i ljudskom aktivnošću kao što je izlijevanje nafte, neodgovarajuće odlaganje otpada ili uslijed požara. U prvom dijelu istraživanja provedena su preliminarna ispitivanja koja su obuhvatila različite metode priprave uzoraka za određivanje PAU-a, PCB-a i OCP-a u lebdećim česticama u zraku, ukupnoj taložnoj tvari (UTT) i tlu. Postupci kojima je bilo moguće optimalno istovremeno odrediti spojeve iz sve tri grupe primijenjeni su na uzorke UTT-a, frakcije lebdećih čestica PM10 i tla s različitih lokacija u Gradu Zagrebu i okolici. Tijekom tri godine (2020. – 2023. godina) kontinuirano su sakupljani mjesečni uzorci UTT-a na deset lokacija, a tjedni uzorci frakcije lebdećih čestica PM10 sakupljani su na jednom mjernom mjestu tijekom 2022. godine. Kompozitni uzorci površinskog sloja tla uzeti su na istim lokacijama 2022. godine te je provedena fizikalno-kemijska karakterizacija tla i određen sadržaj elemenata. Pronađene su razlike u tokovima taloženja PAU-a između mjernih mjesta, ali su se pokazale statistički značajne samo za PAU-e s četiri aromatska prstena i benzo[a]piren u UTT-u na nekim mjernim mjestima. Za PCB-e i OCP-e u UTT-u nije pronađena statistički značajna razlika između mjernih mjesta. Značajne sezonske razlike u tokovima taloženja uočene su za PAU-e, pojedine heksa- i hepta-PCB-e te izomere HCH, pri čemu su najviše vrijednosti zabilježene zimi. Masene koncentracije spojeva PAU, HCH, DDT i njegovih razgradnih produkata u frakciji lebdećih čestica PM10 bile su značajno više zimi, dok se kod PCB-a sezonski minimum i maksimum razlikovao ovisno o stupnju kloriranja kongenera. Dijagnostički omjeri PAU-a i rezultati faktorske i rojne analize te analize glavnih komponenti, pokazuju prisutnost različitih izvora onečišćenja, ovisno o mjernom mjestu i godišnjem dobu (izgaranje biomase, nafte i fosilnih goriva, emisije iz prometa), dok se prisutnost PCB-a i OCP-a povezuje s povijesnim ili prekograničnim unosima. Primijenjeni statistički alati upućuju na kompleksne međusobne odnose između spojeva te su različito grupirali mjerna mjesta, ovisno o promatranoj sastavnici okoliša. Uz karakter mjernog mjesta i lokalne izvore, na razine PAU-a, PCB-a i OCP-a utječe i sam geografski položaj mjernog mjesta, što je vjerojatno povezano s različitim režimom oborina i strujanja zraka. Značajne linearne korelacije između PAU-a u UTT-u i frakciji lebdećih čestica PM10 te između PCB-a s višim stupnjem kloriranja u UTT-u i frakciji lebdećih čestica PM10 upućuju na zaključak da suho taloženje vjerojatno ima značajnu ulogu u uklanjanju tih spojeva iz atmosfere. Odnosi između pojedinih PAU-a, PCB-a i OCP-a u tlu i UTT-u ukazuju na složene mehanizme kruženja tih spojeva u okolišu.Air pollution is a global issue that leads to various negative outcomes to human health and the environment. Particulate matter in the air, especially that with an equivalent aerodynamic diameter of less than 10 μm (PM10) and 2.5 μm (PM2.5), has been proven to have harmful effects and can contain various toxic substances. Polycyclic aromatic hydrocarbons (PAHs) are compounds of particular interest due to their harmful carcinogenic effects, while polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) belong to the group of persistent organic pollutants characterized by persistence, bioaccumulation, and toxicity. Atmospheric deposition, including dry and wet deposition, is crucial for removing pollutants from the air, but it can have negative effects on ecosystems and, indirectly, on human health. Harmful organic compounds enter the soil through natural deposition processes, as well as due to local events such as oil spills, improper waste disposal, and fires. In the first part of this study, preliminary investigations were conducted, covering various sample preparation methods for determining PAHs, PCBs, and OCPs in particulate matter, total deposited matter (TDM), and soil. Procedures that showed optimal results for the simultaneous determination of all three groups of compounds were selected. The optimized methods were applied to samples of PM10, TDM, and soil at various polluted locations in the city of Zagreb and its surroundings. Over three years (2020–2023), monthly TDM samples were continuously collected at ten locations, and weekly samples of the PM10 fraction of airborne particles were collected at one measurement site in 2022. Additionally, composite samples of the surface soil layer were collected at the same locations in 2022, and the physical and chemical characteristics of the soil and the elements present were determined. Differences in PAHs deposition fluxes between measurement sites were found, but were statistically significant only for PAHs with 4 aromatic rings and benzo[a]pyrene in TDM at some locations.
No statistically significant difference between locations was found for PCBs and OCPs in TDM. Significant seasonal differences in deposition fluxes were observed for PAHs, some hexa- and hepta-PCBs, and HCH isomers, with the highest values recorded in winter. The mass concentrations of PAHs, HCH, DDT and its degradation products in the PM10 were significantly higher in winter, while the seasonal minimum and maximum for PCBs differed depending on the chlorination degree of the compound. The diagnostic ratios of PAHs and results of factor analysis, cluster analysis, and principal component analysis indicated the presence of different pollution sources, depending on the location and season (biomass burning, petroleum and fossil fuel combustion, traffic emissions), while PCBs and OCPs were associated with historical or transboundary inputs. The applied statistical tools indicated complex relationships between compounds and differently grouped locations depending on the observed environmental compartment. In addition to local sources, the geographical location of the measurement site also affects the levels of PAHs, PCBs, and OCPs, likely related to different precipitation regimes and airflow patterns. Significant linear correlation between PAHs in TDM and PM10, as well as between PCBs with higher degrees of chlorination in TDM and PM10, suggested that dry deposition likely played a significant role in removing these compounds from the atmosphere. Relationships between individual PAHs, PCBs, and OCPs in soil and TDM indicated the complex circulation mechanisms of these compounds in the environment
Application of metallographic replicas during plastic deformation of low carbon steel
No full textPoznavanje raspodjele naprezanja i deformacija te promjene u mikrostrukturi od ključne su važnosti za razumijevanje procesa koji se odvijaju tijekom plastične deformacije, odnosno oblikovanja deformiranjem u industrijskoj proizvodnji. Raspodjela promjene temperature, odnosno naprezanja, i deformacija danas se mogu detaljno odrediti metodama termografije i digitalne korelacije slike (eng. DIC - digital image correlation). Kako bi se odredile promjene u mikrostrukturi koje se javljaju tijekom plastične deformacije korištena je metoda metalografskih replika. Obzirom na vrlo kompleksnu i složenu pripremu ispitnih uzoraka za istovremeno ispitivanje metodama statičkog vlačnog ispitivanja, termografije, digitalne korelacije slike i metalografskim replikama u ovom istraživanju provedeno je ispitivanje mogućnosti primjene metalografskih replika na niskougljičnom čeliku tijekom hladne plastične deformacije uz istovremeno korištenje prehodno navedenih metoda. U odabranim točkama ispitivanja uzimane su metalografske replike s ispitne površine nakon čega je provedena analiza mikrostrukture niskougljičnog čelika. Analiza mikrostrukture i primjena metalografskih replika u ovom radu povezana je s promjenama temperature odnosno naprezanjima i deformacijama niskougljičnih čelika dobivenih metodama termografije i digitalne korelacije slike. Istraživanja su pokazala da je moguće primijeniti istovremeno metode statičkog vlačnog ispitivanja, digitalne korelacije slike, termografije i metalografskih replika tijekom plastične deformacije niskougljičnog čelika. Utvrđeno je da je s ovim načinom ispitivanja moguće, bez razaranja materijala, ispitati i povezati raspodjelu promjena temperature, odnosno naprezanja, i deformacija te mikrostrukturne promjene tijekom plastične deformacije niskougljičnog čelika, ali i ostalih metalnih materijala. Zaključeno je da se ispitivanjem mikrostrukture metalografskim replikama mogu utvrditi promjene koje su posljedice utjecaja hladne plastične deformacije.The knowledge of stress and strain distribution and microstructural changes has a great importance for understanding the processes of plastic deformation during metal forming in industrial production. Today, the distribution of temperature changes, i.e. stress, and strains can be determined in detail using thermography and digital image correlation (DIC - digital image correlation). In order to determine the microstructure changes that occur during plastic deformation, the method of metallographic replicas was used. In this study, the possibility of applying metallographic replicas to low-carbon steel during cold plastic deformation using static tensile testing, thermography, digital image correlation and metallographic replicas simultaneously was tested, as the sample preparation for simultaneous testing with the aforementioned methods is very complex. At the selected test points, metallographic replicas were taken from the test surface and the microstructure analysis of the low-carbon steel was performed. In this work, microstructural analysis and the application of the metallographic replicas are related to the temperature changes, i.e. the stresses and strains of the low-carbon steel obtained by thermography and digital image correlation. Research has shown that it is possible to simultaneously apply static tensile testing, digital image correlation, thermography and metallographic replicas during the plastic deformation of low-carbon steel. It was found that with these test methods it is possible to investigate and relate the temperature changes, i.e. the stress and strain distribution and the microstructural changes during plastic deformation of low-carbon steels, but also of other metallic materials, without destroying the material. It was found that by examining the microstructure with metallographic replicas, it is possible to determine the changes that can be attributed to the influence of cold plastic deformation
One-pot synthesis of a fully protected trisaccharide from linear oligosaccharide domain of Quillaja saponaria plant saponin
No full textU sklopu ovog diplomskog rada sintetiziran je potpuno zaštićeni trisaharid β-D-Xylp-(1→4)-α-L-Rhap-(1→2)-D-Fucp koji je ujedno i strukturna domena saponina QS-21 izoliranog iz biljke Quillaja saponaria, nužna za njegovu imunoadjuvantsku aktivnost. Metoda sinteze glikozidne veze korištena u ovom diplomskom radu koristi glikozil-fluoride kao donore glikozila te sililne etere kao akceptore. Za razliku od standardnih reakcija glikozilacije, ova metoda ne zahtijeva rigorozne suhe uvjete, niti hlađenje na niske temperature, već se odvija uz komercijalno dostupan katalizator, borov trifluorid dietileterat, pri sobnoj temperaturi i u otapalu koje ne mora biti sušeno. Korištenje navedenih prekursora otvara mogućnost tzv. one-pot glikozilacije, odnosno povezivanja nekoliko reakcija glikozilacije u jedan sintetski korak. Strategija one-pot glikozilacije korištena u sintezi ciljnog trisaharida iskorištava suptilne razlike u reaktivnosti različitih sililnih etera. Konačni prekursori i produkt sinteze strukturno su okarakterizirani standardnim spektroskopskim metodama (IR, 1H i 13C NMR).n this diploma thesis, a fully protected trisaccharide β-D-Xylp-(1→4)-α-L-Rhap-(1→2)-D-Fucp was synthesized. This trisaccharide is a structural domain of saponin QS-21, which is isolated from the plant Quillaja saponaria and is essential for its immunoadjuvant activity. The glycosidic bond synthesis method used in this thesis employs glycosyl fluorides as glycosyl donors and silyl ethers as acceptors. Unlike standard glycosylation reactions, this method does not require rigorous dry conditions nor cooling to low temperatures. Instead, it utilizes a commercially available catalyst, boron trifluoride diethyl etherate, at room temperature and in a solvent that does not need to be dried. The use of these precursors opens up the possibility of one-pot glycosylation, connecting several glycosylation reactions into a single synthetic step. The one-pot glycosylation strategy used in this synthesis exploits subtle differences in the reactivity of various silyl ethers. The final precursors and the product were structurally characterized using standard spectroscopic methods (IR, 1H, 13C NMR)
Computational analysis of the correlation between vaginal microbiota and HPV status in the general female population
No full textIako zauzima oko 9% mikrobioma žena, mikrobiom rodnice važan je za zdravlje ženskog reproduktivnog sustava. Zdrav mikrobiom rodnice karakterizira visoka zastupljenost bakterijskog roda Lactobacillus koji, osim snižavanjem pH, rodnicu često štiti proizvodnjom vodikova peroksida (H2O2). Mikrobiom se može proučavati metodama uzgoja bakterija, ali je na taj način nemoguće zabilježiti cjelokupnu mikrobnu bioraznolikost, niti je jednostavno proučavati ulogu, funkciju i interakciju mikrobioma s ogranizmom domaćinom. Umjesto toga, zahvaljujući napretku visokoprotočnog sekvenciranja, koristi se metagenomika. Njome se mikrobiom može proučavati izravno, bez uzgoja pojedinih vrsta ili sojeva, čime se, uz pripadajuću bioinformatičku analizu, mikrobiom može bolje taksonomski opisati, a omogućava se i njegovo funkcijsko opisivanje, primjerice analizom učestalosti upotrebe kodona. Pomoću dobivenih izvornih očitanja visokoprotočnog sekvenciranja metagenoma 10 uzoraka prikupljenih tijekom dobrovoljnog davanja brisa rodnice u svrhu testiranja na HPV, odredio sam taksonomski sastav mikrobioma unutar kraljevstva bakterija na svim taksonomskim razinama. Na temelju tih rezultata uzorke sam grupirao, te sam odredio gene i metaboličke puteve kojima su pojedine skupine uzoraka obogaćene. U konačnici sam ustanovio da postoje statistički značajne razlike između pojedinih skupina uzoraka u skladu s dosadašnjom literaturom, ali nisam mogao odrediti koje taksonomske skupine ili koja funkcija mikrobioma je povezana s povećanom zarazom HPV-a.Although it occupies only about 9% of female's microbiome, microbiome of the uterus is important for the health of the female reproductive system. A healthy uterine microbiome is characterised by high abundance of bacterial genus Lactobacillus. The genus is protecting uterus by lowering its pH and producing hydrogen peroxide. Microbiome can be studied by cultivation method, which is unable to cover much of a microbial diversity and it is not providing easy functional analysis. Metagenomic is an alternative method enabled by high-throughput sequencing. It can be used for a direct taxonomic characterization of a microbiome, without prior cultivation, and it facilitates functional analysis of codon bias, by applying proper bioinformatic tools. I determined taxonomic composition for kingdom of Bacteria for all taxonomic levels to group 10 samples taken from volunteers that gave the samples from uterus to test them for the presence of HPV infection. Additionally, I determined genes and metabolic pathways for which the samples were enriched. Finally, I found that certain metadata is statistically significantly different between the samples in accordiance with current literature, but I could not determine which taxonomic units or function of microbiom are in correlation with HPV infection