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Analysis of CAD activities in a multi-user CAD environment
No full textUpotreba CAD (eng. Computer Aided Design) alata važna je u kasnijim fazama razvoja proizvoda. Korištenjem CAD alata, razvojni tim kreira digitalni model proizvoda. Tradicionalni CAD alati omogućuju asinkroni rad na digitalnim modelima čime je otežana kolaboracija između članova tima. Razvojem računarstva u oblaku omogućeni je razvoj višekorisničkih CAD alata. Jedan od vodećih višekorisničkih CAD alata smještenih u oblaku (eng. Cloud-based software) je Onshape® tvrtke PTC koja omogućuje sinkroni rad više članova tima na istom modelu. Onshape® omogućuje kontinuirano praćenje aktivnosti članova razvojnog tima prilikom CAD modeliranja. Za potrebe rada korišteni su podaci o CAD aktivnostima studentske udruge koja se bavi izradom raketa. U praćenom razdoblju postoje zapisi o 18453947 aktivnosti proizašlih od strane 491 korisnika (članova tima). Na samom početku rada provedeno je istraživanje postojeće literature vezanu za analizu CAD aktivnosti što je uvelike pomoglo definiranju pristupa samoj analizi podataka. Analiza aktivnosti podijeljena je u tri dijela. U sklopu prvog dijela generirane su grupe korisnika i Onshape dokumenata s obzirom na broj zabilježenih aktivnosti, te je provedena analiza aktivnosti za svaku generiranu grupu. U drugom dijelu analize, za potrebe klasteriranja dokumenata i korisnika, korišteni su K-Means i GMM algoritam. Pomoću oba algoritma provedeno je klasteriranje podataka o aktivnostima te su navedeni rezultati analize. Struktura CAD aktivnosti grupa dokumenata i korisnika ovisi o pristupu grupiranja istih. Generirani klasteri pomoću dva različita algoritma daju drugačije rezultate ističući pojedine klastere (s obzirom na strukturu CAD aktivnosti) od ostalih klastera U sklopu trećeg dijela analize odrađeni je pregled kolaboracije unutar tima. Korisnici (Članovi tima) Analiziranjem dinamike promjena mreže kolaboracije utvrđeno je postojanje podtimova koji rade zajedno, ali ti podtimovi variraju na mjesečnoj bazi.The usage of CAD (Computer-Aided Design) tools is important in the later stages of product development. With CAD tools, the design team can create digital models of the product. Traditional CAD (single-user CAD) tools enable work from one PC and one user at a time on a single CAD model. This restriction makes collaboration more difficult.
The development of cloud computing has enabled the creation of multi-user CAD tools. One of the leading multi-user CAD tools is Onshape, a PTC company product that allows more than one user to work on a CAD model simultaneously. Onshape also enables tracking of user activity using the Audit Trail module.
For this master’s thesis, a dataset of CAD activity from a student association involved in rocket design is used. During the tracking period, 18,453,947 CAD activity were recorded from 491 users. At the beginning of this work, a survey of the existing literature related to the analysis of CAD activities was conducted, which greatly helped define the approach to data analysis.
The analysis of CAD activity is divided into three parts. The first part involves grouping users and Onshape documents based on the number of recorded timestamps. Each created group is analyzed separately. In the second part, GMM (Gaussian Mixture Model) and K-Means clustering algorithms are used to generate clusters of documents and users. Clustering of data for CAD activity is performed using each algorithm, and the results are compared. Each approach to data grouping provides different insights into the structure of CAD activity. The use of different clustering algorithms results in the creation of some clusters that differ in their approach to CAD activity.
The last part is the analysis of user collaboration. After analyzing the dynamics of the collaboration network, the existence of sub-teams was established, but only on a monthly basis
Development of belt tensioner for bicycle with rear suspension
No full textU ovom radu prikazan je razvoj zatezača remena za bicikl sa stražnjom suspenzijom. Razvoj je
započet kratkim uvodom i prikazom problema kojeg je potrebno riješiti. Potom je provedena
analiza patenata i postojećih proizvoda na tržištu. Pomoću funkcijske dekompozicije i
morfološke matrice koja iz nje slijedi – generirana su tri koncepta zatezača remena za bicikl sa
stražnjom suspenzijom. Na temelju vrednovanja izabran je koncept za daljnju konstrukcijsku
razradu. Nakon konstrukcijske razrade model zatezača remena kontroliran je numeričkom
analizom metode konačnih elemenata. Također, proveden je i dinamički proračun sigurnosti
ležaja i tijela zatezača. Nad usvojenim modelom, nakon zadovoljavanja proračuna, proveden je
proces topološke optimizacije. Na koncu su izvršene konačne evaluacije novog modela pomoću
prethodno spomenutih metoda. Konačno rješenje je diskutirano i predloženi su eventualni
pravci daljnjeg razvoja zatezača remena.The topic of this thesis is the development of belt tensioner for bicycle with rear suspension.
The development was started with a short introduction and presentation of the problem that
needs to be solved. An analysis of patents and existing products on the market was then carried
out. By means of the functional decomposition and the morphological matrix that follows from
it – three concepts of belt tensioners for bicycle with rear suspension were generated. Based on
the evaluation, a concept was chosen for further design development. After the design
development, the belt tensioner model was controlled by numerical analysis of the finite
element method. Also, a dynamic calculation of the safety of the bearing and tensioner body
was carried out. After satisfying the engineering analysis, the topological optimization process
was carried out over the adopted model. Finally, the final evaluations of the new model were
performed using the previously mentioned methods. The final solution was discussed and
possible directions for further development of the belt tensioner were proposed
Phospholipid nanosystems with thymol: preparation, characterization and in vitro antimicrobial assessment
No full textRastući trend rezistencije bakterija na antibiotike predstavlja veliki javnozdravstveni problem koji zahtjeva istraživanja novih učinkovitih djelatnih tvari i formulacija. Jedna od takvih bakterija je MRSA, glavni uzročnik bolničkih infekcija s visokim stupnjem mortaliteta. Timol, izoliran iz različitih biljnih vrsta porodice Lamiaceae, pokazao je značajan antimikrobni učinak i dobro djelovanje na MRSU; međutim, zbog svoje lipofilnosti ima ograničenu terapijsku primjenu. S ciljem poboljšanja farmakokinetičkih svojstava i bioraspoloživosti timola, pripremljene su različite fosfolipidne nanoformulacije s uklopljenim timolom kojima su određena fizikalno-kemijska svojstva (veličina liposoma, indeks polidisperznosti, zeta potencijal) i ispitan antimikrobni učinak. Korištenjem visokotlačne homogenizacije pripravljene su fosfolipidne disperzije koje omogućuju visoko uklapanje timola, sa srednjim promjerima vezikula manjim od 200 nm. Ispitivanja in vitro antimikrobne aktivnosti pokazala su da većina pripremljenih fosfolipidnih nanoformulacija s uklopljenim timolom ne pokazuje bolji antimikrobni učinak od otopine timola.The growing trend of antibacterial resistance represents a major public health problem. It requires research of a new antimicrobial substances that should be effective and safe for human use. MRSA is a major cause of hospital-acquired infections with a high mortality rate. Thymol, isolated from different plant species of the Lamiaceae family, showed a significant antimicrobial effect against MRSA. However, due to its lipophilicity, thymol has limited therapeutic use. To improve the pharmacokinetic properties and bioavailability of thymol, it was incorporated into phospholipid-based nanoformulations, vesicular phospholipid gels and conventional liposomes. They were evaluated for the physicochemical properties (mean diameter, polydispersity index, zeta potential) and in vitro antibacterial effect. Vesicular phospholipid gels with thymol, prepared by high-pressure homogenization, resulted with high incorporation of thymol in vesicles smaller than 200 nm. In vitro antibacterial evaluation showed that most of the prepared phospholipid nanoformulations with incorporated thymol did not show a better antimicrobial effect than thymol solution
Synthesis and characterization of a proteolysis-targeting chimera (PROTAC) for the targeted degradation of glycogen synthase kinase 3Beta (GSK3Beta) And dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A)
No full textAlzheimerova bolest (AB) jedna je od najčešćih neurodegenerativnih bolesti današnjice. Terapija ove bolesti ograničena je na nekoliko lijekova koji djeluju simptomatski te ne dovode do izlječenja, zbog čega je potrebno kontinuirano istraživati i razvijati nove lijekove koji ciljaju nove mete s potencijalom za modificiranje tijeka bolesti. Posljednjih godina istražuje se mogućnost ciljanja različitih signalnih molekula uključenih u patofiziologiju AB, uključujući kinazu glikogen sintaze 3 (GSK3) i dvospe-cifične tirozinskom fosforilacijom regulirane kinaze 1A (DYRK1A).
Cilj ovog rada je sinteza i karakterizacije nove kimere koja usmjerava ciljanu proteolizu (PROTAC) GSK3β i DYRK1A. Ciljni PROTAC sastoji se od tri dijela: liganda za ciljne proteine (harmin) i liganda za E3 ligazu (talidomid) koji su povezani alkil-triazolskom poveznicom. U svrhu priprave PROTAC-a potrebno je sintetizirati odgovarajuće prekursore: azid 3 i alkin harmina 6 te karboksilnu kiselinu talidomida 5. Sinteza alkina 6 odvija se u jednom reakcijskom koraku, alkiliranjem harmina propargil-bromidom u bazičnim uvjetima. Azid 3, prekursor alkiltriazolske poveznice, sintetiziran je u tri koraka iz etanolamina. Derivat talidomida 5 sintetiziran je 4-hidroksitalidomida i tert-butil-2-bromoacetata pri čemu nastaje eter kojem se u drugom koraku skida tert-butiloksikarbonilna zaštitna skupina (Boc) trifluoroctenom kiselinom. Alkin 6 i azid 3 povezani su preko 1,2,3-tria-zolskog prstena u jednom reakcijskom koraku Huisgenovom 1,3-dipolarnom cikloadicijom. Spoju 7 je uklonjen Boc s amino skupine u kiselim uvjetima pri čemu nastaje amin 8. PROTAC 9 dobiven je coupling reakcijom između karboksilne kiseline talidomida 5 i amina 8 uz pomoć coupling reagensa HATU.
Novosintetizirani spoj karakteriziran je analitičkim i spektroskopskim metodama (1H i 13C NMR, MS i FT-IR) te su mu web alatom SwissADME predviđeni fizičko-kemijski parametri koji procjenjuju ograničenu oralnu bioraspoloživost i nemogućnost prolaska krvno-moždane barijere. Također se predviđa da je PROTAC 9 inhibitor CYP enzima i supstrat P-glikoproteina. Spo-sobnost razgradnje ciljnih kinaza bit će ispitana u daljnjim istraživanjima.Alzheimer's disease (AD) is one of the most common neurodegenerative diseases today. The therapy for this disease is limited to only a few drugs that only alleviate symptoms but do not cure nor significantly modify disease progression. Therefore, continuous research to develop new disease-modifying drugs for new targets is necessary. In recent years, the possibility of targeting various signal molecules involved in the pathophysiology of AD, including glycogen synthase kinase 3 (GSK3) and dual specificity tyrosine-phosphorylation-regulated kinase 1A (DYRK1A), has been investigated.
The aim of this study is to synthesize and characterize a novel proteolysis-targeting chimera (PROTAC) for the targeted degradation of GSK3β and DYRK1A. The target PROTAC consists of three parts: a ligand for proteins of interest (harmine) and a ligand for E3 ligase (thalidomide) linked by an alkyltriazole linker. To prepare PROTAC, it is necessary to synthesize the appropriate precursors: azide 3, harmine alkyne 6, and the carboxylic acid of thalidomide 5. The synthesis of alkyne 6 is carried out in a single reaction step by alkylation of harmine with propargyl bromide in the presence of a base. Azide 3, a precursor of the alkyltriazole linker, is synthesized in three steps from ethanolamine. The thalidomide derivative 5 is synthesized from 4-hydroxythalidomide and tert-butyl-2-bromoacetate to form an ether 4, from which, in the second step, tert-butyloxycarbonyl protecting group (Boc) is removed with trifluoroacetic acid. Alkyne 6 and azide 3 are connected via a 1,2,3-triazole ring in a single reaction step by Huisgen 1,3-dipolar cycloaddition. The removal of Boc from the amino group of compound 7 gives an amine 8. PROTAC 9 was obtained in the coupling reaction between the carboxylic acid of thalidomide 5 and amine 8 using the coupling reagent HATU.
The novel compound is characterized by analytical and spectroscopic methods (1H and 13C NMR, MS, and FT-IR). The SwissADME web tool predicted limited oral bioavailability and blood-brain barrier penetration, based on the physicochemical properties. PROTAC 9 is also predicted to be a CYP inhibitor and a P-glycoprotein substrate. The potential for the degradation of target kinases will be investigated in further studies
The Optimisation of the Computer Image Analysis Method for Evaluating the Quality of Bread with Added Acorn Flour
No full textOvaj diplomski rad usmjeren je na razvoj i verifikaciju automatiziranog postupka računalne analize slike za procjenu kvalitete kruha s dodatkom brašna od žira (Quercus rotundifolia). U istraživanju su analizirani različiti algoritmi segmentacije slike kako bi se odredili ključni parametri strukture kruha, uključujući broj šupljina, prosječnu veličinu šupljina i poroznost. Algoritmi kao što su Default, IsoData, Li, Moments i Otsu pokazali su se najprikladnijima za analizu, pružajući konzistentne rezultate, dok se IsoData algoritam posebno istaknuo kao najuspješniji zbog svoje stabilnosti i pouzdanosti. Nasuprot tome, algoritmi poput MinError, MaxEntropy, Yen i Triangle pokazali su manju učinkovitost zbog varijacija u rezultatima i nerealne filtracije, osobito kod uzoraka s kompleksnom strukturom. Istraživanje je pokazalo da veći udio brašna od žira povećava broj šupljina, prosječnu veličinu šupljina i poroznost kruha, pri čemu uzorci s 100% brašna imaju najvišu vrijednost ovih parametara. Povećanje udjela vode iznad 100% smanjilo je broj šupljina, ali je povećalo prosječnu veličinu šupljina i poroznost kod uzoraka s brašnom od žira. U uzorcima bez žira, udio vode nije imao značajan utjecaj, što ukazuje na ključnu ulogu brašna od žira u formiranju strukture kruha.This thesis deals with the development and verification of an automated image analysis method for the evaluation of the quality of bread with the addition of acorn flour (Quercus rotundifolia). In the study, different image segmentation algorithms were analysed to determine important structural parameters of the bread, including the number of voids, average void size and porosity. Algorithms such as Default, IsoData, Li, Moments and Otsu were found to be the most suitable for the analysis and provided consistent results, with the IsoData algorithm standing out as the most successful due to its stability and reliability. In contrast, algorithms such as MinError, MaxEntropy, Yen and Triangle were less effective due to fluctuations in results and unrealistic filtering, especially for samples with complex structure. The study showed that a higher proportion of acorn flour increased the number of voids, the average void size and the porosity of the bread, with samples containing 100% acorn flour having the highest values for these parameters. Increasing the water content above 100% reduced the number of voids but increased the average void size and porosity in samples with acorn flour. In samples without acorn flour, the water content had no significant effect, emphasising the key role of acorn flour in shaping the bread structure
The connection between knowledge sharing, innovative work behavior and hidden employee
No full textOvaj diplomski rad istražuje povezanost dijeljenja znanja, inovativnog radnog ponašanja i
skrivenog inoviranja zaposlenika, polazeći od pretpostavke da su ovi procesi međusobno
povezani i ključni za organizacijsku uspješnost u suvremenom, dinamičnom poslovnom
okruženju. Teorijski dio rada temelji se na relevantnoj znanstvenoj literaturi iz područja
upravljanja znanjem, organizacijskog ponašanja i inovacijskog menadžmenta. Naglasak je
stavljen na ulogu tacitnog znanja, koje se prenosi neformalno i često nesvjesno, a pokazuje se
posebno važnim u generiranju kreativnih rješenja i inovativnih ideja. Inovativno radno
ponašanje definira se kao niz aktivnosti zaposlenika koje uključuju generiranje, promociju i
implementaciju novih ideja, dok se skriveno inoviranje odnosi na neformalnu, često
neautoriziranu praksu razvoja inovacija izvan službenih okvira organizacije. Empirijski dio
rada temelji se na kvantitativnoj analizi prikupljenih podataka putem anketnog upitnika
provedenog među zaposlenicima iz različitih organizacija. Rezultati istraživanja provedenog
na uzorku od 108 zaposlenika iz različitih poduzeća pokazuju statistički značajnu povezanost
između dijeljenja znanja i inovativnog radnog ponašanja, kao i između inovativnog ponašanja
i sklonosti skrivenom inoviranju. Također je potvrđeno da inovativno ponašanje zaposlenika
djelomično posreduje odnos između dijeljenja znanja i skrivenog inoviranja. Ovi nalazi
upućuju na to da se sustavno poticanje dijeljenja znanja može pozitivno odraziti na spremnost
zaposlenika da aktivno sudjeluju u inovacijskim procesima, bilo formalno, bilo kroz skriveno
inoviranje. Rad daje teorijski doprinos razumijevanju odnosa između znanja i inovacija, a
istovremeno nudi i praktične implikacije za organizacije koje žele potaknuti kulturu dijeljenja,
kreativnosti i neformalne inovativnosti..This thesis explores the connection between knowledge sharing, innovative work behavior and
employee latent innovation, starting from the assumption that these processes are
interconnected and crucial for organizational success in a modern, dynamic business
environment. The theoretical part of the paper is based on relevant scientific literature in the
field of knowledge management, organizational behavior and innovation management.
Emphasis is placed on the role of tacit knowledge, which is transmitted informally and often
unconsciously, and has proven to be particularly important in generating creative solutions and
innovative ideas. Innovative work behavior is defined as a series of employee activities that
include the generation, promotion and implementation of new ideas, while latent innovation
refers to the informal, often unauthorized practice of developing innovations outside the official
framework of the organization. The empirical part of the paper is based on a quantitative
analysis of data collected through a questionnaire conducted among employees from different
organizations. The results of the research on 108 employees from different companies show a
statistically significant connection between knowledge sharing and innovative work behavior,
as well as between innovative behavior and a tendency to latent innovation. It was also
confirmed that innovative behavior partially mediates the relationship between knowledge
sharing and latent innovation. These findings suggest that systematically encouraging
knowledge sharing can positively affect employees' willingness to actively participate in
innovation processes, either formally or through latent innovation. The paper makes a
theoretical contribution to the understanding of the relationship between knowledge and
innovation, while also offering practical implications for organizations that want to foster a
culture of sharing, creativity, and informal innovation
The development of cultural and creative industries as a catalyst for urban regeneration in Trnje
No full textUrbana regeneracija vrlo je kompleksan proces koji zauzima sve važnije mjesto u razvoju postindustrijskih gradova. Ona nastoji dovesti do poboljšanja gospodarskih, društvenih, fizičkih i okolišnih uvjeta u zapuštenim područjima. Postoje različiti pristupi urbanoj regeneraciji, a u ovom radu je istražen pristup kroz razvoj i djelovanje kulturnih i kreativnih industrija. Kulturne i kreativne industrije važan su sektor u novoj ekonomiji koji nudi različite usluge i mogućnosti za razvoj gradova – bilo to u kontekstu povećanja gospodarske konkurentnosti, poticanju društvenog i kulturnog razvoja ili oblikovanju fizičkih elemenata u prostoru. Prostorni obuhvat istraživanja je administrativno područje zagrebačke gradske četvrti Trnje, s fokusom na tzv. brownfield područjima. U radu su istražene prilike koje nudi urbana regeneracija temeljena na razvoju kulturnih i kreativnih industrija, uz identifikaciju izazova koji se pojavljuju u njenom planiranju. Konzultacijom relevantne znanstvene i stručne literature te istraživačkom metodom intervjua dobiveni su rezultati prema kojima su određena načela i uvjeti za kvalitetno planiranje urbane regeneracije u GČ Trnje, s naglaskom na kulturnu komponentu.Urban regeneration is a highly complex process that is becoming increasingly important in the development of post-industrial cities. It aims to improve the economic, social, physical, and environmental conditions in neglected areas. There are various approaches to urban regeneration, and this paper explores the approach based on the development and operation of cultural and creative industries. Cultural and creative industries are a key sector in the new economy, offering a range of services and opportunities for urban development – whether through enhancing economic competitiveness, fostering social and cultural growth, or shaping the physical elements of urban space. The spatial scope of the research is the administrative area of the Trnje district in Zagreb, with a focus on so-called brownfield sites. The paper examines the opportunities offered by urban regeneration based on the development of cultural and creative industries, while also addressing the challenges that arise in its planning. Through a review of relevant scientific and professional literature and the use of the interview research method, the findings provided a basis for identifying principles and conditions for high-quality urban regeneration planning in the Trnje district, with an emphasis on the cultural component
Snake venoms and their application
No full textLjekovita svojstva otrova zmija čovjeku su poznata već dugi niz godina. Njihova primjena u tradicionalnoj
medicini potaknula je mnoge znanstvenike da detaljnije istraže njegove komponente. Rezultati istraživanja
redovno pokazuju mnoga korisna svojstva otrova koja se mogu primijeniti pri liječenju bolesti poput raka te
pri liječenju srčanih bolesti koje predstavljaju liječnicima velik izazov. Zahvaljujući modernim tehnikama
istraživanja otkriva se sve više novih komponenata otrova koje se mogu iskoristiti za proizvodnju novih
lijekova.The healing properties of snake venoms have been known to man for many years. Their application in
traditional medicine has inspired many scientists to investigate its components in more detail. The results of
research regularly show many useful properties of toxins that can be used in the treatment of diseases such as
cancer and in the treatment of heart disease, which is a great challenge for doctors. Thanks to modern research
techniques, more and more new components of toxins are being discovered that can be used to produce new
drugs
Priprava i karakterizacija vezikularnog fosfolipidnog gela s timolom
No full textCilj istraživanja
Cilj ovog istraživanja bila je priprava i evaluacija vezikularnog fosfolipidnog gela (VFG) s
timolom, namijenjenog dermalnoj primjeni. Optimizirani su uvjeti priprave VFG-a, te je ispitan
utjecaj sastava VFG-a na fizikalna svojstava vezikula (liposoma) unutar VFG-a, oslobađanje
timola i reološke karakteristike formulacija.
Materijali i metode
Eksperimentalni dio rada obuhvaćao je izradu VFG-ova s timolom različitog (fosfo)lipidnog
sastava metodom visokotlačne homogenizacije. Provedeno je određivanje fizikalno-kemijskih
svojstava VFG-ova s timolom (srednji promjer, indeks polidisperznosti, zeta potencijal
liposoma unutar VFG-ova) te ispitivanje topljivosti timola u različitim otapalima kako bi se
odredio prikladan medij za provođenje ispitivanja in vitro oslobađanja. Ispitivanja in vitro
oslobađanja timola iz odabranih formulacija VFG-ova i kontrole (otopina timola) provedena
su metodom dijalize, a oslobođeni timol je određen spektrofometrijski. Reološka
karakterizacija formulacija uključivala je rotacijska (profil viskoznosti) i oscilatorna (test
promjene amplitude) mjerenja.
Rezultati
Visokotlačnom homogenizacijom uz primjenjeni tlak od 500 bara pripravljena su dva različita
tipa VFG-a srednjih promjera liposoma od 140 do 200 nm i blago negativnog zeta potencijala
(-5 do -8 mV). Postignuto je produljeno oslobađanje timola iz oba tipa VFG-a u odnosu na
kontrolu, pri čemu je (fosfo)lipidni sastav značajno utjecao na udio oslobođenog timola.
Prisustvo kolesterola u formulaciji je rezultiralo polaganijim oslobađanjem timola u odnosu na
formulaciju pripravljenu isključivo iz sojinog fosfadilkolina. (Fosfo)lipidni sastav VFG-a
utjecao je i na reološka svojstva formulacija. VFG pripravljen bez kolesterola bio je neznatno
viskozniji u odnosu na VFG s kolesterolom, dok temperatura na kojoj su provedena mjerenja
nije utjecala na viskoznost formulacija. Oba tipa VFG-a su pokazala viskoelastična svojstva
prikladna za dermalnu primjenu (G' > G“ u linearnom viskoelastičnom području).
Zaključak
Rezultati provedenih ispitivanja u sklopu ovog rada ukazuju na mogućnosti primjene VFG-a
kao inovativne polučvrste podloge za dermalnu dostavu timola. Reološkom karakterizacijom
potvrđena su pseudoplastična svojstva pripravaka, kojima se omogućuje produljeno
oslobađanje timola. Daljnjim ispitivanjima (permeabilnost kroz kožu, antimikrobni učinak,
biokomaptibilnost) procijenila bi se prikladnost formulacija VFG-ova s timolom za primjenu
na kožu.Objective
The aim of this research was to prepare and evaluate a vesicular phospholipid gel (VPG) for
dermal delivery of thymol. The preparation conditions of VPGs were optimized, and the impact
of the (phospho)lipid composition of the VPG on the release of thymol, physico-chemical
properties of the liposomes within the VPGs, and the rheological characteristics of the
formulations, was examined.
Material and Methods
Thymol-loaded VPGs of different (phospho)lipid composition were prepared using the highpressure homogenization method at applied pressure of 500 bar. The physicochemical
properties of liposomes within the thymol-loaded VPGs were determined (mean diameters,
polydispersity indexes, zeta potentials) and the solubility of thymol in different solvents was
tested in order to determine a suitable medium for conducting in vitro release studies. In vitro
release of thymol from the selected VPGs and the control (thymol solution) were performed
using the dialysis method, while the released thymol was determined spectrophotometrically.
Rheological characterization of the formulations included rotational (viscosity profile) and
oscillatory (amplitude test) measurements.
Results
Two different types of VPGs, with liposomes exhibiting mean diameters of 140 - 200 nm and
a slightly negative zeta potentials (-5 to -8 mV), were prepared by high-pressure
homogenization method. Prolonged release of thymol from the both types of VPGs was
achieved compared to the control, whereby the (phospho)lipid composition had a significant
effect on the release of thymol. The presence of cholesterol in the VPG resulted in a slower
release of thymol compared to the VPG prepared exclusively from soy phosphadylcholine. The
(phospho)lipid composition of VPGs also affected the rheological properties of the
formulations. VPG prepared without cholesterol was slightly more viscous compared to VPG
with cholesterol, while the temperature at which the measurements were carried out did not
affect the viscosity of the formulations. Both types of VPGs showed viscoelastic properties
suitable for dermal application (G' > G“, in linear viscoelastic region).
Conclusion
The results of all conducted studies indicate the suitability of VPG as an innovative semisolid
vehicle for dermal delivery of thymol. The rheological characterization confirmed the
pseudoplastic properties of VPGs, which enabled the prolonged release of thymol. However,
further investigations are required, such as skin permeability studies, antimicrobial testing, and
biocompatibility assessment, to evaluate the suitability of thymol-loaded VPGs for skin
application
Static Calculation of Business Building : Undergraduate Thesis
No full textU radu je prikazan statički proračun poslovne zgrade. Poslovna zgrada sastoji se od prizemlja, četiri etaže i ravnog krova. Nosiva konstrukcija građevine izvedena je od armiranog betona. Projekt sadrži tehnički opis, proračun nosivih konstrukcijskih elemenata te karakteristične građevinske nacrte.The static design of business building is presented in this work. The building consist of four stories, ground floor and flat roof. Structure is made of reinforced concrete. The work includes technical description of the structure, calculation of the main structural elements and characteristic structural plans