Hacettepe Üniversitesi Açık Erişim Sistemi (HÜAES)
- HÜAES, Hacettepe Üniversitesi bünyesinde üretilen kitap, makale, tez, bildiri, rapor gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, etkisini artırmak için telif haklarına uygun olarak Açık Erişime sunar.
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Meme Kanseri için Hedeflenebilir İlaç Salım Sistemi Olarak İkili İlaç Yüklü Albümin Bazlı Nanopartiküllerin Geliştirilmesi
(Fen Bilimleri Enstitüsü, 2025) Türkeş Ezgi; Biyomühendislik
Current areas of research in cancer include the development of carriers to allow alternative dosage routes, new therapeutic targets such as blood vessels that feed tumor growth, and more specific targeted therapies. An ideal drug delivery system should have optimal physical-chemical properties such as enhanced targeting ability, low toxicity and controlled drug release profile. Within the scope of this thesis, different albumin-based
drug carrier formulations in the nano-size range have been prepared especially for breast cancer. Protein-polymer hybrid nanoparticles in the structure of poly(lactic-co-glycolic acid):albumin core-shell were synthesized based on nanoprecipitation method and particle size and size distribution were optimized. Active and passive targeting approaches are predominantly studied in current cancer therapy research. All synthesized particle formulations are suitable for passive targeting by trying to keep the targeted size in the range of 100-200nm, and formulations suitable for active targeting have been prepared by taking advantage of the albumin layer conjugated to the surface of the formulation, albumin being a nitrogen and energy source in the body, allowing the encapsulation of a second drug, and accumulating in tumor areas. In poly(lactic-coglycolic acid):albumin protein-polymer hybrid nanoparticles, Docetaxel, a chemotherapeutic active ingredient, was encapsulated in the core of the poly(lactic-coglycolic acid) and curcumin, a chemosensitizing and chemopreventive active ingredient, was encapsulated in the albumin layer forming the shell. In current studies carried out for
the treatment of breast cancer, studies showing the importance of the combined use of Docetaxel and Curcumin in order to overcome drug resistance, to increase cell apoptosis by creating a synergistic effect, and to increase the effectiveness of treatment by sensitizing cells to chemotherapy. In addition to protein-polymer hybrid nanoparticles in the structure of Poly(lactic-co-glycolic acid):albumin core-shell synthesized for this
purpose, nanoparticle formulations of both polymer and protein alone were also prepared. In this way, it was possible to compare both polymer-protein hybrid and protein nanoparticles in terms of size, charge, drug release, etc. On the other hand, the surface of the prepared formulations was conjugated with folic acid and thus synthesis, characterization and drug release studies of formulations suitable for specific targeting of cancer cells carrying folate receptors were carried out. For the synthesized formulations, characterization studies such as size analysis and zeta potential measurements with Zetasizer, SEM, FTIR, TGA, DSC, XRD, contact angle measurements were carried out. The encapsulation efficiencies and loading capacity values of the drug-loaded formulations were calculated, both single and dual in vitro drug release studies were investigated by dialysis method at 37oC in pH 5.6 PBS buffer media simulating acidic tumor microenvironment and pH 7.4 PBS buffer media simulating physiological blood, and compliance with different drug release kinetic models (Zero Order, First Order,
Higuchi, Hixson-Crowell and Korsmeyer-Peppas) was examined.
Bigadiç (Balıkesir) Borat Havzası Ayana Sahasındaki Birimlerin Mineralojik ve Jeokimyasal İncelenmesi
(Fen Bilimleri Enstitüsü, 2025) Gülaydın Gözde Emine; Jeoloji Mühendisliği
It is aimed to determine the mineralogical, petrographic and geochemical
properties of the units in the Ayana Plain of the Bigadiç Borate Basin, to determine the lateral and vertical distribution of neoformation minerals (borate, clay, carbonate, zeolite and sulfate) and to interpret the paleogeographic development of the basin. A total of 363 core samples were taken from 4 different drillings (20BM - 613, 20BM - 619, 20BM - 632 and 20BM - 644) in Ayana Plain from Değirmenli Tuff Member, Uzun Tepe Member, Emirler Member and İskele Member of Bigadiç Formation. On these samples, mineralogical-petrographic examinations were conducted, including XRD (whole rock and clay fraction), optical microscopy, and SEM-EDS; geochemical analyses were performed, including major and trace element analyses as well as boron isotope analysis. XRD - whole rock analysis
of all samples was performed and as a result, illite / mica, amphibole, clay, quartz, opal - CT, feldspar, calcite, dolomite, aragonite, analcime, clinoptilolite / heulandite, pyrite, gypsum and anhydrite minerals and borate minerals
(colemanite, ulexite, probertite and howlite) were identified. XRD - clay fraction analysis was performed on 128 selected samples and the analysis revealed the presence of smectite, illite, kaolinite, chlorite and serpentine minerals. Within the scope of SEM - EDS analysis, apatite, chromite, zircon, allanite, galenite and torite minerals were determined in addition to the minerals determined from XRD - Whole rock analysis. 30 samples were analyzed for major and trace elements. According to the results of whole rock analyses, the highest Li values were found to be 60 ppm in Emirler Tuff Member, 90 ppm in Değirmenli Tuff Member, 1210 ppm in İskele Member and 1900 ppm in Uzun Tepe Member. It has been determined that the clay fraction samples containing only smectite are hectorite minerals according to the structural formulas calculated from the geochemical analysis results. It has been determined that samples with high smectite content also have high Li values. The highest value in terms of Li content was determined as 2720 ppm in the clay fraction containing only smectite in the sample taken from the borated zone of Uzun Tepe Member. According to these results, Li enrichment is associated with Mg-rich smectite minerals. Therefore, it was revealed that borate deposits are important in terms of lithium potential. Boron isotope analyses were performed on the minerals ulexite (δ¹¹B: - 4.3‰ and - 4.9‰), probertite (δ¹¹B: - 4.0‰), colemanite (δ¹¹B: - 9.1‰) and howlite (δ¹¹B: -
15.1‰ and δ¹¹B: - 14.7‰). According to boron isotope data, the origin of the
borates was determined as non-marine evaporite. The observation of analcime mineral in the Uzun Tepe Member in drillings 20BM-619 and 20BM-644 indicates that salinity, alkalinity and pH were high during the deposition of the Uzun Tepe Member in this part of the Ayana Plain.
İç Anadolu’da Marnlı Bir Bozkır Habitatında Yetişen Dar Yayılışlı ve Yaygın Bitkilerin Polinatör Böcek Çeşitliliği Örüntüleri
(Fen Bilimleri Enstitüsü, 2025) Kırgıl Gülseli; Biyoloji
Pollination is the transfer of pollen from the anthers to the stigma of plants. Insects play a key role in pollination, and floral visitors contribute to process at varying levels. In ecology, understanding the factors shaping species distribution patterns is a central focus. Pollen limitation, defined by inadequate or poor-quality pollen receipt, can occur when pollinators
are insufficient or ineffective, influencing plant distribution. Specialized and generalist behaviors relate to resource use capacity of taxa. Limited niche breadth indicates specialization, while broader niche breadth in generalists allows tolerance to diverse conditions. Differences in these behaviorsbetween plants and pollinators may also affect plant distribution, and most insights into these interactions are achievable only through an interaction network approach. While pollinator effects on plant distribution have been examined from various angles, diversity patterns of pollinators across plant distribution
groups remain understudied. This thesis investigates whether plant distribution patterns are associated with the taxon richness, diversity, visitation frequency, and taxonomic composition of insect pollinators. Fieldwork was conducted in marl steppe habitats in Sivrihisar, Eskişehir, on three species each from narrowly distributed endemic, widespread
endemic, and widespread non-endemic plant groups. For each species, pollinator observations were carried out on five individuals, and additional general samples were taken. Flower samples were collected for eDNA metabarcoding. Observational samples were categorized into pollinator insects and other floral visitors, with analyses conducted
separately for pollinators and all-inclusive visitor groups. Taxon richness and visitation frequency were analyzed using generalized linear models based on Poisson distribution. Taxon diversity was assessed using the Shannon index, general linear models, and one-way ANOVA. For taxon composition, non-metric multidimensional scaling and non-parametric multivariate analysis of variance were performed, and Jaccard similarity index was used for
taxon similarity. Interaction network analyses were also conducted. Results showed differences in the communities formed by pollinators and all visitors across plant distribution groups. Narrowly distributed plants had significantly lower taxon richness, diversity, and visitation frequency for both pollinators and all visitors, whereas widespread non-endemic plants had the highest values. This suggests that pollen limitation may be occurring in
narrowly distributed plants due to reduced pollinator visitation. However, no distinct differences were found in community composition between groups. This may be explained by the distributional variability of pollinator taxa among plants and broad variation within the data. While eDNA metabarcoding enabled the detection of some hard-to-observe floral visitors, it failed to yield data specific to pollinator insects. This study identifies the
pollinator insects present in Central Anatolia's marl steppe ecosystem and their interactions with plant species exhibiting different distribution patterns. Its findings provide valuable insights for improving conservation strategies, especially for narrowly distributed and endemic species, by incorporating species interactions into planning.
Kontrollü ve Sıralı Büyüme Faktörü Salımı için Manyetik Silika/Aljinat Mikroküreler Kullanılarak Manyetik Duyarlı Kemik Doku İskelelerinin Geliştirilmesi
(Fen Bilimleri Enstitüsü, 2025) Polat Görkem; Biyomühendislik
This thesis aims to develop magnetically responsive composite tissue scaffolds that allow controlled and sequential release of growth factors in the field of bone tissue engineering. The developed system is composed of magnetic silica nanoparticles (MMSNs) and alginate (ALG) microspheres combined with a collagen/hydroxyapatite (COL/HA) matrix. Thus, synchronized release of osteogenic (BMP-2) and angiogenic (VEGF)
growth factors with physiological timing was targeted. Firstly, silica nanoparticles were synthesized with an expanded pore structure, surface
modified with amino groups and modified with citric acid coated Fe₃O₄ nanoparticles to obtain MMSN structures. Then, protein delivery and release profile of MMSNs loaded with bovine serum albumin as a model protein were investigated. In parallel, alginate microspheres synthesized by ionic cross-linking were designed for the prolonged release of growth factors. These carriers were combined with COL/HA matrix to form three
dimensional porous tissue scaffolds. Characterization studies were performed by FT-IR, BET, DLS, VSM, XRD, TGA and SEM analysis. Release studies with magnetic field application revealed that MMSNs provide triggerable and controlled protein release, while ALG microspheres offer an early
onset and sustained release profile. Biocompatibility analyses by MTT assay revealed that the scaffolds support cell viability. Furthermore, RT-qPCR analyses showed that the developed system promoted osteogenic differentiation by increasing the expression of RUNX2, COL1A1, ALP and OCN genes. The data revealed that magnetic field-triggered systems are effective in precisely controlling the timing of growth factor release and that a sequential release strategy can physiologically promote osteogenic differentiation. In this respect, the developed platform offers a promising strategy for the repair of critical bone defects. In conclusion, this thesis study has demonstrated the bone regeneration-promoting effects of magnetic field-sensitive composite systems based on controlled and sequential growth factor release and contributed to the development of new generation smart tissue scaffolds.
Nejat Başeğmezler’in Suite Adlı Eserinin Biçim, Armonik Yapı ve Bestecilik Teknikleri Açısından İncelemesi
(Güzel Sanatlar Enstitüsü, 2026) Vecihe Cansu Yılmaz; Kompozisyon ve Orkestra Şefliği
Nejat Başeğmezler is a composer recognized for his productivity, diverse output, and distinctive musical language, particularly through his works written for viola, chamber ensembles, and orchestra. His sustained compositional activity across both the twentieth and twenty-first centuries, as well as his engagement with the musical transformations that characterized these periods, renders the study of his works particularly significant. Within this context, Suite (1997), composed for string orchestra, constitutes the primary focus of this artistic research report.
The aim of this study is to examine the work in terms of its form, harmonic structure, and compositional techniques, and to clarify the evaluation of the work by elucidating Başeğmezler’s musical perspective through his own statements. Furthermore, the study evaluates, through a descriptive approach, the manner in which Başeğmezler approaches the suite tradition within a contemporary context as reflected in the work itself. Within this framework, the aforementioned work constitutes the scope of the study.
The data collection and analysis process was conducted in three stages. In the first stage, a review of the relevant literature was carried out; sources related to the suite genre were examined, and the work was analyzed in terms of its form, harmonic structure, and compositional techniques through the method of document analysis. In the second stage, a semi-structured interview technique was employed, allowing the composer to articulate his approach to the work in his own words. In the final stage, the findings of the musical analysis and the interview data were considered together, enabling a comprehensive evaluation of the work within a holistic framework.
The findings of this study reveal Nejat Başeğmezler’s approach to the suite tradition in his work, particularly in terms of form, harmonic structure, and compositional techniques.