Uludag University Academic Repository
Not a member yet
50710 research outputs found
Sort by
Kişiye özgü humerus protezi dizaynı için humerus’un proksimal bölümünün morfometrik özelliklerinin tahmin edilmesi
No full textThe human arm and shoulder joint depend on the humerus, which is the bone that bears the most weight in the upper limb. An individual's quality of life could be affected by a humeral fracture; the rigid geometry of current prosthetic systems complicates the process of obtaining anatomical restoration after arthroplasty. This study aimed to generate hypotheses about the morphometric properties of the proximal end of the humerus, derived from the morphometric characteristics of the distal end of the individual's humerus, to enable the construction of a personalized humeral prosthesis. There were 33 dry humerus bones used in the study; IBM SPSS Statistics was used for statistical analysis. This paper developed predictive linear regression models using 33 dry humeral bones in order to determine proximal humerus morphometric features. The approach showed developments in patient-specific humeral prosthetic design and offers a solution to problems related with current standardized prosthetic systems. The thorough approach, clinically relevant approach, and clear presentation of results of the study make it a major source for building patient-specific humeral prosthesis. The developed equations might improve surgical results and patient quality of life. Validating these equations in vivo using CT imaging and clinical data should be given priority in future studies.İnsan kolu ve omuz eklemi, üst ekstremitedeki en fazla ağırlık taşıyan kemik olan humerus'a bağlıdır. Bir bireyin yaşam kalitesi, bir humerus kırığı tarafından etkilenebilir; mevcut protez sistemlerinin kalıp geometrisi, artroplasti sonrası anatomik restorasyon elde etme sürecini karmaşıklaştırır. Bu çalışmada, bireyin humerus'unun distal ucunun morfometrik özelliklerinden türetilen, humerus'un proksimal ucunun morfometrik özellikleri hakkında hipotezler oluşturmak amaçlandı ve böylece kişiselleştirilmiş bir humeral protez dizaynı geliştirme yönünde yeni formüller ortaya kondu. Çalışmada 33 kuru humerus kemiği kullanıldı; istatistiksel analiz için IBM SPSS Statistics v28.0 kullanıldı. Bu makale, proksimal humerus morfometrik özelliklerini belirlemek amacıyla 33 kuru humerus kemiği kullanarak öngörücü doğrusal regresyon modelleri geliştirmiştir. Yaklaşım, hasta spesifik humeral protez tasarımında gelişmeler gösterdi ve mevcut standartlaştırılmış protez sistemleriyle ilgili sorunlara bir çözüm sundu. Kapsamlı yaklaşım, klinik olarak ilgili yaklaşım ve çalışmanın sonuçlarının net sunumu, hasta spesifik humeral protezlerin oluşturulmasında önemli bir kaynak haline getiriyor. Geliştirilen denklemler, cerrahi sonuçları ve hasta yaşam kalitesini artırabilir. Bu denklemlerin in vivo olarak CT görüntüleme ve klinik veriler kullanılarak doğrulanması, sonraki çalışmalarda ön planda olmalıdır
Investigation of mechanical and interface behaviors of natural fiber reinforced polymer matrices
No full textKompozit malzemeler günümüzde hemen hemen tüm endüstriyel ve teknolojik alanlarda yaygın olarak kullanılmaktadır. Bu malzemeler ağırlıklı olarak sentetik elyaf takviyeleri ve termoset bazlı matris sistemleri kullanılarak üretilmektedir. Ancak termoset bazlı malzemelerin kürlendikten sonra geri dönüştürülemediği iyi bilinmektedir. Son yıllarda, sürdürülebilirlik ve çevresel etkinin azaltılması konusundaki küresel farkındalık, doğal elyaf takviyeli termoplastik kompozit malzemelere olan ilginin artmasına yol açmıştır. Bu ilgi, elektrikli araç pazarının genişlemesine paralel olarak bu tür malzemelere giderek daha fazla yönelen otomotiv endüstrisinde özellikle belirgindir. Bu tez kapsamında takviye elemanı olarak kenevir elyafı seçilirken, matris malzemesi olarak polipropilen iplik ve polipropilen granülleri kullanılmıştır. Polipropilen, hibrit iplik, kumaş ve granül formunda kullanılmış ve sıcak pres kalıplama yöntemi kullanılarak üç farklı kompozit plaka üretilmiştir. Elde edilen kompozit numuneler, ISO standartlarına uygun olarak üç nokta eğilme, Izod darbe, çekme ve darbeli delinme testlerine tabi tutulmuş ve elde edilen veriler buna göre analiz edilmiştir.Composite materials are widely used in almost all industrial and technological fields today. These materials are predominantly produced using synthetic fiber reinforcements and thermoset-based matrix systems. However, it is well known that thermoset-based materials are non-recyclable once cured. In recent years, global awareness of sustainability and the reduction of environmental impact has led to a growing interest in natural fiber-reinforced thermoplastic composite materials. This interest is particularly evident in the automotive industry, which is increasingly turning to such materials in parallel with the expansion of the electric vehicle market. In the scope of this thesis, hemp fiber was selected as the reinforcing element, while polypropylene yarn and polypropylene granules were used as the matrix material. Polypropylene was utilized in the form of hybrid yarn, fabric, and granules, and three different composite plates were produced using the hot press molding method. The resulting composite samples were subjected to three-point bending, Izod impact, tensile, and drop-weight impact tests in accordance with ISO standards, and the obtained data were analyzed accordingly.ELVİN TEKSTİ
The role of personality traits and decision-making styles in career decision-making difficulties
No full textCareer decisions are one of the most important decisions individuals make in their lives. These decisions are multifaceted and complex, making them a challenging process, particularly for students. This creates obstacles for students navigating the career choice process. The aim of this study is to examine career decision-making difficulties within the framework of personality traits and decision-making styles. The target group of this study is undergraduate students studying at a public university. For this research, we collected data through online questionnaire forms. The questionnaire comprised demographic questions and three scales: career decision-making difficulties, personality traits, and decision-making styles. A total of 505 students (63.2% female) participated in the questionnaire. The research model was tested using path analysis. We also conducted network analysis in order to better understand and visualize the relationships between the sub-dimensions of the scales. The findings showed significant direct relationships between career decision-making difficulties and personality traits (conscientiousness, openness, neuroticism, and agreeableness) and decision-making styles (rational, dependent, avoidant, and spontaneous). According to the path analysis result, neurotic personality traits were positively correlated with career decision-making difficulties, while openness to experience, agreeableness, and conscientiousness were negatively correlated with them. The relationship between dependent, avoidant, and spontaneous decision-making styles and career decision-making difficulties was positive. These results provide valuable insights into the factors that shape career decisions, helping students make more informed choices and manage their career paths effectively
The relationship of strength-based parenting with the negative effects of earthquake: Mediating roles of optimism, resilience and mindfulness
No full textEarthquakes are natural disasters whose devastating effects are widely known and in early February 2023, 11 provinces in T & uuml;rkiye were deeply shaken. It was important to examine the protective factors against the negative effects of earthquakes to develop effective interventions and significant recovery. Hitherto, research in the literature focused more on the negative effects of the disaster and paid less attention to the conditions under which the forces that support well-being, such as optimism, resilience, and mindfulness. Thus, in the current study, we tested the relationship between Strength-based Parenting and depression, anxiety, and stress symptoms and the mediating role of optimism, resilience, and mindfulness in such a relationship. 408 university students who survived the devastating earthquake were included in the study. Participants filled out the Strength-Based Parenting Scale, Optimism and Pessimism Scale, Brief Resilience Scale, Mindfulness Scale, and Depression, Stress, Anxiety Scale (DASS-21). In the results, strength-based parenting was found to be positively correlated with optimism, resilience, and mindfulness while negative correlations were detected with depression, anxiety, and stress. Moreover, optimism, resilience, and mindfulness were found to mediate the relationship between strength-based Parenting and depression, anxiety, and stress. In this manner, the results showed that strength-based parenting has a protective role against the negative effects of the earthquake by contributing to optimism, resilience, and mindfulness. Thus, strength-based parenting appears promising in natural disaster studies
Reinforcement of polylactic acid parts manufactured additively by material extrusion method by adding monofilament polyester mesh interlayers
No full textThis study investigates the use of monofilament polyester mesh interlayers to enhance the mechanical performance of PLA parts produced by fused filament fabrication (FFF). Through tensile and bending tests conducted on samples manufactured with varying numbers of reinforcement layers (0, 1, 2) and extrusion temperatures (210 degrees C, 230 degrees C, 250 degrees C), it was determined that extrusion temperature significantly influences mechanical properties; low temperatures led to insufficient adhesion issues, while increasing temperatures generally improved strength. It was also found that polyester mesh reinforcement particularly increased tensile strength at low temperatures, but this effect diminished or became negative at higher temperatures. In conclusion, this research suggests that the incorporation of reinforcement mesh interlayers in FFF offers a promising hybrid approach to improve mechanical properties with proper parameter selection
An engineering approach to perceived quality in automotive product development
No full textAlgılanan kalite, müşterinin bir ürün hakkında henüz bilgisi çok kısıtlıyken algıladığı kalite seviyesidir. Müşterinin ürün hakkında bilgisi kısıtlı olduğu için, ürünün ilk izleniminin çok iyi olması istenir. Müşteri algısını içerdiği için soyut bir kavram olarak ele alınabilir. Bu çalışma, soyut bir kavram olan algılanan kalitenin otomotivde ölçülebilir metriklere dönüştürülmesini amaçlamıştır. Bu amaçla, araç kapıları, otomotivde algılanan kaliteye mühendislik yaklaşımı sergilemek üzere örnek parça olarak seçilmiştir. Araç kapıları, açılıp kapanma, güvenlik ve estetik gibi çok boyutlu görevler üstlenir. Araç gövdesine bağlantıları sadece menteşeler ve kilit ile yapılmasına rağmen, aracın üzerinde sanki gövde ile kapılar tek parçaymış gibi uyum göstermesi beklendiği için özellikle kapılar üzerinde çalışılacak parça olarak seçilmiştir. İlk bölümde algılanan kalite kavramı ele alınırken, ikinci bölümde detaylı literatür araştırması ile otomotivde algılanan kalite kavramı, araç kapıları fonksiyonel ve estetik isterler, araç kapılarının açma kapama enerjisinin hesaplanması gibi konular ele alınarak araç kapılarında algılanan kalite beklentilerinin listelenmesi ile bölüm tamamlanmıştır. Üçüncü bölümde ise, kapılarda açma kapama hoşnutluğu için kayar kapılarda açma kapama kolu müşteri beklentilerinden tasarıma kadar ele alınmıştır. Bu alanda, algılanan kalitenin tasarıma girdi sağlanması hedeflenmiştir. Müşteri odaklı (KFG, Kano) modelleri yanı sıra, istatiksel yöntemler (Taguchi, Pugh matris) kullanılarak rijit bir tasarımı amaçlanmıştır. Paralel olarak, üçüncü bölümde, kapıların açma kapama enerjisinin hesaplanması için, araç üzerinden alınan ölçümlere yer verilmiştir. Dördüncü bölümde ise, araç kapılarının enerji hesaplamaları için bulunan bulgular tartışılmıştır. Pearson analizi yapılarak etkenler analiz edilmiş ve akabinde regresyon analizi ile bir model önerilmiştir. Bu çalışmaların doğrulanması ile son olarak, algılanan kalitenin modellenmesi ve optimizasyonuna odaklanılmıştır. Bu çalışma, otomotiv özelinde algılanan kalitenin tasarım aşamasından ele alınması için bir rehber olmakla beraber, farklı sektörlere de uygulanabilir.Perceived quality refers to the level of quality a customer senses about a product when they still have very limited information about it. As the customer’s knowledge is restricted at this stage, perceived quality is crucial. This study aims to transform the initial concept of perceived quality into measurable metrics in the automotive industry. For this purpose, vehicle doors were selected as a case study component to demonstrate an engineering approach to perceived quality in automotive applications. Vehicle doors perform multidimensional functions such as opening and closing, ensuring safety, and providing aesthetic appeal. Although they are connected to the vehicle body only through hinges and locks, they are expected to align seamlessly with the body as if they were a single piece—making them a particularly relevant focus for this study. The first section discusses the concept of perceived quality. In the second section, a detailed literature review explores perceived quality in the automotive context, expectations from vehicle doors, and the calculation of door opening and closing energy. This section concludes with a list of perceived quality expectations for vehicle doors. In the third section, the focus shifts to sliding doors, examining the opening and closing handle from customer expectations to design. The goal here is to incorporate perceived quality as an input into the design process. In addition to customer-focused models (KFG, Kano), statistical methods (Taguchi, Pugh matrix) are used to achieve a robust design. In parallel, this section also includes measurements taken from the vehicle to calculate the energy required to open and close the doors. The fourth section discusses the findings from the energy calculations of vehicle doors. A Pearson analysis is conducted to examine the influencing factors, followed by a regression analysis to propose a model. With the validation of these studies, the final focus is on results of the study. While this study serves as a guide for addressing perceived quality from the design phase in the automotive industry, it is also applicable to other sectors
Estimation of PCDD/F levels in soil and aquatic environments using the atmospheric concentrations in an urban site
Get PDFPoliklorlu dibenzo-p-dioksinler ve dibenzofuranlar (PCDD/F’ler) Stokholm Sözleşmesi’nin EK-C kısmında listelenmiş, insan ve çevre sağlığı açısından önemli risk teşkil eden kalıcı organik kirleticilerdendir. PCDD/F’ler kaynaktan salındıktan sonra atmosferik çökelme ve dağılım mekanizmaları ile toprak ve su ortamına karışabilmektedirler. Biyolojik olarak zor bozunabilme özellikleri sayesinde bu ortamlarda yaygın olarak bulunabilmekte ve farklı canlı ve ortamlara taşınabilmektedirler. PCDD/F’lerin farklı ortamlardaki konsantrasyon seviyelerinin belirlenmesi bu kirleticilerin davranış mekanizmalarının anlaşılması açısından önem taşımaktadır. Türkiye’de toprak ortamı için oldukça az sayıda ölçüm verisi bildirilmiş olup sucul ortam için bildirilen herhangi bir veri bulunmamaktadır. Bu çalışmada Bursa şehrinin kentsel bir bölgesinde dört mevsimi kapsayacak şekilde ölçümü yapılmış olan atmosferik PCDD/F konsantrasyonları kullanılarak çeşitli denge durumu eşitlikleri yardımı ile toprak ve sucul ortamlardaki PCDD/F konsantrasyon seviyelerinin araştırılması amaçlanmıştır. Buna göre toprak ve sucul ortam için hesaplanan ortalama PCDD/F konsantrasyonlarının sırasıyla 702,74±553,74 pg/g (21,14±13,41 pg TEQ/g) ve 0,8±0,61 pg/L (0,12±0,08 pg TEQ/L) olduğu belirlenmiştir. Bu değerlerin literatürde bildirilen çeşitli çalışmalar ile uyum içinde olduğu görülmüştür. En yüksek konsantrasyon değerleri iki ortam için de kış ayları için hesaplanmış, mevsimsel etkinin konsantrasyon seviyeleri üzerindeki etkisi açıkça gözlemlenmiştirPolychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are persistent organic pollutants listed in Annex C of the Stockholm Convention, which pose a significant risk to public and environmental health. PCDD/Fs, after being released from the source, can enter the soil and water environment through atmospheric deposition and partition mechanisms. Due to their characteristic of difficult biodegradability, they can be widely found in these environments and can be transported to different living organisms and environments. Determination of the concentration levels of PCDD/Fs in different environments is important for understanding the behavioural mechanisms of these pollutants. In Türkiye, few measurement data have been reported for the soil environment, and currently, there is no data reported for the aquatic environment. In this study, it was aimed to investigate the PCDD/F concentration levels in soil and aquatic environments by using atmospheric PCDD/F concentrations measured over four seasons in an urban area of Bursa city by means of various equilibrium equations. Accordingly, the mean total PCDD/F concentrations estimated for soil and aquatic environment were 702.74±553.74 pg/g (21.14±13.41 pg TEQ/g) and 0.8±0.61 pg/L (0.12±0.08 pg TEQ/L), respectively. These values were found to be in agreement with various studies reported in the literature. The highest concentration values were estimated in winter months for both environments, and the effect of seasonal effect on concentration levels was clearly observed
Retrospective evaluation of clinical features, imaging, and biochemical parameters in patients diagnosed with osteoporosis treated with teriparatide
Get PDFGiriş ve Amaç: Osteoporoz, düşük kemik kütlesi ve kemiğin mikro mimari yapısının bozulma sonucu kırılganlık artışı ile karakterize kronik bir kemik hastalığıdır. Anabolik bir ajan olan teriparatid tedavisinin, şiddetli osteoporoz hastalarında kemik mineral yoğunluğunu (KMY) artırdığı ve kırık riskini azalttığı gösterilmiştir. Bu çalışmanın amacı, osteoporoz tanısı ile teriparatid tedavisi kullanan hastaların klinik özelliklerinin, biyokimyasal ve görüntüleme parametrelerinin retrospektif olarak değerlendirilmesi, tedavi etkinliği ve olası yan etkilerinin incelenmesidir. Yöntem: Bursa Uludağ Üniversitesi Tıp Fakültesi’nde 01/01/2017-01/09/2023 yılları arasında teriparatid tedavisi başlanan 53 hasta değerlendirilmiştir. Hastaların demografik verileri, komorbid hastalıkları, tedavi süreleri ve yan etkiler incelenmiş; tedavi öncesi ve sonrası kırık öyküsü, KMY ve biyokimyasal parametreler karşılaştırılmıştır. Bulgular: Tedavi başlanan 48 hastanın verileri tam olan 47’sinden %57,4’ü 18 aylık tedavi süresini tamamladı. Ortalama tedavi süresi 14,5 ay olarak bulundu. Biyokimyasal tetkikler incelendiğinde nötrofil ve lökosit sayısındaki azalma dışında istatistiksel olarak anlamlı değişiklik saptanmadı. Lomber vertebra KMY’sinde anlamlı bir artış gözlenirken (p=0,011), femur boynundaki artış istatistiksel olarak anlamlı bulunmadı (p=0,201). Yan etki nedeniyle tedaviyi bırakma oranı %5 idi. Yeni kırık gelişme oranı %2,3 olarak saptandı. Sonuç: Teriparatid tedavisi, lomber KMY’de anlamlı artış sağlayarak etkili ve güvenli bir seçenek olduğunu göstermiştir. Ancak tedaviye devam oranlarının düşük olması, etkinliği sınırlamaktadır. Hasta eğitimine yönelik programların geliştirilmesi ve takiplerin iyileştirilmesi tedavi başarısını artırabilir.Introduction and Objective: Osteoporosis is a chronic bone disease characterized by low bone mass, impaired microarchitecture, and increased fragility. Teriparatide, an anabolic agent, has been shown to increase bone mineral density (BMD) and reduce fracture risk in patients with severe osteoporosis. This study aims to retrospectively evaluate the clinical characteristics and biochemical and imaging parameters of patients receiving teriparatide therapy, as well as to assess its efficacy and potential side effects. Methods: A total of 53 patients who began teriparatide therapy at Bursa Uludağ University Faculty of Medicine between January 1, 2017, and September 1, 2023, were evaluated. Demographic data, comorbidities, treatment durations, and side effects of the patients were examined. Fracture history, BMD, and biochemical parameters before and after the treatment were compared. Results: Among 48 patients started treatment, 47 patients whose data were complete included in the study. Of 47 patients 57.4% completed the 18-month treatment period, with an average treatment duration of 14.5 months. Biochemical tests indicated no statistically significant changes, except for a decrease in the number of neutrophils and leukocytes. A significant increase in lumbar spine BMD was observed (p=0.011), while the increase in femoral neck BMD was not statistically significant (p=0.201). The rate of treatment discontinuation due to side effects was 5%, and the incidence of new fractures was 2.3%. Conclusion: Teriparatide therapy is an effective and safe treatment option, significantly improving lumbar BMD. However, low treatment adherence limits its overall efficacy. Developing patient education programs and enhancing follow-up strategies may improve treatment outcomes
Contributions of cartograph prof. dr. murat yakar to the field of epigraphy
No full textFrom the past to the present, the world's nations have given importance to maps and cartography. The science of cartography has gained great importance, especially in the current century. Considering the development of cartography in Turkey, significant developments have been made in the last 30 years. Many works have been added to the relevant literature, and many have been trained at undergraduate, graduate, and doctoral levels. This study provides information about the value that Prof. Dr. Murat YAKAR, one of the leading scientists of Turkey and the world in the fields of cartography and photogrammetry in particular, and the contribution he has made to the field of epigraphy. Prof. Dr. Murat YAKAR stands out as an important scientist in the fields of cartography and photogrammetry, as well as in Turkish and world academia, with his professional experience of over 30 years, published articles, and papers, many of which are the first in their fields and books that are reference sources, and scientific journals that he founded and edited in national and international arenas. Information is provided with visuals about Prof. Dr. Murat YAKAR, who contributed to the field of epigraphy, such as the detection of inscriptions, the relationship of inscriptions and related areas with cartography, the mapping of important geographies of the Turkish world, and the determination of underground inscriptions, with the influence of the projects he took part in in the geography extending from Asia to Europe
Second-generation braf inhibitor encorafenib resistance is regulated by ncoa4-mediated iron trafficking in the drug-resistant malignant melanoma cells
No full textThe current study established the first in vitro Encorafenib resistance protocol in BRAF-mutated malignant melanoma (MM) cells and investigated the resistance-related mechanisms. After establishing Encorafenib-resistant A375-MM cells, resistant-related mechanisms were investigated using WST-1, Annexin V, cell cycle, morphological analysis, live-cell, Western blot, RNA-Seq, transmission electron microscopy-(TEM), oxidative stress and iron colorimetric assay. The most resistant group, called A375-R, was determined in the cells treated with a constant dose of 10 nM over 3 months. The viability, apoptosis, and G0/G1 arrest reflected the acquired chemoresistance. Autophagic Beclin and LC3 proteins, and AKT signaling increased in the A375-R. RNA-Seq results also exhibited altered epigenetic regulation of resistance; particularly ferritin family members, ion transport pathways. Then, increased NCOA4, FTH1, and iron levels detected in A375-R suggest that the iron metabolism-related mechanism, such as ferritinophagy, might be triggered, which was supported by TEM and oxidative stress analysis. Iron storage, transport, and ferritinophagy have the promising potential to be targeted for combining with BRAF-targeted therapy to reverse Encorafenib resistance in MM. Moreover, this is the first study evaluating in vitro Encorafenib resistance mechanisms, and we suggest that our findings contribute to improving new drug combinations targeting BRAF and iron metabolism in different MM cells