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Permanent URI for this collectionhttps://hdl.handle.net/20.500.14288/3
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Publication Metadata only Neuro-ophthalmic and neuro-otologic evaluation in individuals with motion sickness susceptibility(Aves, 2024) Aydin, Kubra; Kara, Eyyup; Uzun Adatepe, Nurten; Ataş, Ahmet; School of Medicine; Koç University HospitalBACKGROUND: Since the physiological background of motion sickness is not entirely clear, it was aimed to examine the physiological differences in groups consisting of individuals susceptible and non-susceptible to motion sickness. METHODS: Sixty subjects [motion sickness (MS) group: 33 female, 3 male; 28.8 ± 8.1 years; control group: 19 female, 5 male; 24.5 ± 4.3 years] were included in the study. Near visual acuity test on the treadmill in the presence of visual stimulation, pattern visual-evoked potentials, oculomo-tor tests, and computerized dynamic posturography were applied. Receiver operating characteristic analysis was performed to determine the parameter that provides the excellent discrimination between the groups. RESULTS: The most effective parameter in differentiating the study groups was determined as dynamic visual acuity with 77.8% sensitivity and 95.8% specificity. Significant differences were found in the vestibular (mean ± standard deviation: 0.63 ± 0.17), visual (0.77 ± 0.18), and composite scores (73.11 ± 11.89) of the patients (P = .000) in posturographic evaluation. In the visual-evoked potential examination, a significant decrease was found in the amplitude values between the P100-N145 waves in the binocular (5.0 ± 2.8, P = .002), right eye (7.6 ± 3.2, P = .009) and left eye (7.9 ± 2.9, P = .016) in the symptomatic patients. In binocular oculomotor evaluation, directional asymmetric findings were obtained. CONCLUSION: It has been shown that the most effective test parameter that distinguishes the MS susceptible and non-susceptible individuals is the dynamic visual acuity value. Based on the results of neuro-physiological tests, it was suggested that a possible visual-vestibular integration disorder in individuals susceptible to motion sickness may affect visual and vestibular performance.Publication Metadata only Ethics of deep brain stimulation for neuropsychiatric disorders(Springer, 2024) Darko, K.; Detchou, D.; Barrie, U.; Aydın, Serhat; School of MedicineDeep Brain Stimulation (DBS) has emerged as a revolutionary neurosurgical technique with significant implications for the treatment of various neuropsychiatric disorders. Initially developed for movement disorders like Parkinson’s disease, DBS has expanded to psychiatric conditions such as obsessive-compulsive disorder, depression, anorexia nervosa, dystonia, essential tremor, and Tourette’s syndrome. This paper explores the clinical efficacy and ethical considerations of DBS in treating these disorders. While DBS has shown substantial promise in alleviating symptoms and improving quality of life, it raises ethical challenges, including issues of informed consent, patient selection, long-term management, and equitable access to treatment. The irreversible nature of DBS, potential adverse effects, and the high cost of the procedure necessitate a rigorous ethical framework to guide its application. The ongoing evolution of neuromodulation requires continuous ethical analysis and the development of guidelines to ensure that DBS is used responsibly and equitably across different patient populations. This paper underscores the need for a balanced approach that integrates clinical efficacy with ethical considerations to optimize patient outcomes and ensure sustainable practice.Publication Metadata only Self-supervised object-centric learning for videos(Neural information processing systems foundation, 2023) Xie, Weidi; Department of Computer Engineering; Aydemir, Görkay; Güney, Fatma; Department of Computer Engineering; Graduate School of Sciences and Engineering; College of EngineeringUnsupervised multi-object segmentation has shown impressive results on images by utilizing powerful semantics learned from self-supervised pretraining. An additional modality such as depth or motion is often used to facilitate the segmentation in video sequences. However, the performance improvements observed in synthetic sequences, which rely on the robustness of an additional cue, do not translate to more challenging real-world scenarios. In this paper, we propose the first fully unsupervised method for segmenting multiple objects in real-world sequences. Our object-centric learning framework spatially binds objects to slots on each frame and then relates these slots across frames. From these temporally-aware slots, the training objective is to reconstruct the middle frame in a high-level semantic feature space. We propose a masking strategy by dropping a significant portion of tokens in the feature space for efficiency and regularization. Additionally, we address over-clustering by merging slots based on similarity. Our method can successfully segment multiple instances of complex and high-variety classes in YouTube videos.Publication Metadata only Tracing the phase formation and stability of the clathrate phase BaGe5(Elsevier Inc., 2024) Baitinger, Michael; Grin, Yuri; Burkhardt, Ulrich; Department of Chemistry; Aydemir, Umut; Department of Chemistry; Koç University Boron and Advanced Materials Application and Research Center (KUBAM) / Koç Üniversitesi Bor ve İleri Malzemeler Uygulama ve Araştırma Merkezi (KUBAM); College of SciencesThermal stability and phase formation of the clathrate phase BaGe5 and its formation from the clathrate-I phase Ba8Ge43 square(3) (square = vacancy in the crystal structure) have been investigated by microstructure analysis, differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). The experiments confirm the peritectic formation of the high-temperature phase Ba8Ge43 square(3) from alpha-Ge and liquid at 810 degrees C, and the eutectic temperature of Ba8Ge43 square(3) and Ba6Ge25 at 808 degrees C. At T = 770 degrees C, Ba8Ge43 square(3) decomposes by a eutectoid reaction to Ba6Ge25 and alpha-Ge, and at T = 520 degrees C, the low-temperature phase BaGe5 forms in a peritectoid reaction from these two phases. BaGe5 was synthesized by decomposition of the high-temperature clathrate-I phase Ba8Ge43 square(3) at temperatures between 350 degrees C and 520 degrees C. Annealing and DSC experiments verify that BaGe5 is an equilibrium phase at ambient pressure. The formation of BaGe5 from Ba8Ge43 square(3) was traced through microstructure analysis, revealing microdomains with pleochroic behavior in polarized light.Publication Metadata only Novel vaginal cerclage assisted laparoscopic cervico-sacropexy technique for uterovaginal prolapse(SAGE Publications Ltd, 2024) Aydın, Serdar; Çekiç, Sebile Güler; School of Medicine; Koç University HospitalAim Laparoscopic hysteropexy is a complicated procedure that requires specialized surgical skills, including precise dissection and suturing. The aim is to describe the technical considerations for performing a new, feasible, and minimally invasive technique to correct apical and concurrent apical and anterior vaginal wall defects.Method A retrospective analysis was conducted on 70 consecutive women who underwent surgery for stage >= 3 uterovaginal prolapse. As a part of the technique, an anterior 2-cm long transverse incision was made at the anterior cervicovaginal junction, and the bladder was dissected through blunt and sharp dissection to the level of the isthmus. A posterior colpotomy was performed. A polypropylene tape was inserted into the cervical connective tissue, and the free arms of the tape were inserted into the peritoneum via the posterior colpotomy. Two arms of the tape were passed from the tunnel parallel and medial to a right sacrouterine fold, then fixed to the anterior longitudinal ligament via the laparoscopic route.Results The tape can be inserted into the cervix in a median of 15 min, and the laparoscopy procedure can be completed in 24 min. No mesh erosion or long-term complications occurred. At a 1-year control, there were no cases of recurrence.Conclusions This novel cervico-sacrocolpopexy technique is a feasible and safe, minimally invasive way to correct apical or multicompartment defects, with a short operation time and an anatomical result that mimics the normal sacrouterine ligament.Publication Metadata only Diagnostic value of serum and urine endocan levels in nonmuscle invasive bladder cancer: a prospective comparative study(Wiley-Hindawi, 2024) Aydin, Hasan Riza; Adanur, Senol; Ozkaya, Fatih; Utlu, Adem; Laloglu, Esra; Turgut, Hasan; Demirdogen, Saban Oguz; Akkas, Fatik; Canda, Abdullah Erdem; School of MedicineObjective. This prospective study aimed to explore the potential diagnostic value of endocan levels in bladder cancer by investigating a possible association of serum and urine endocan levels with the stage and grade of bladder tumors in patients with nonmuscle-invasive bladder cancer (NMIBC) in terms of risk stratification. Materials and Methods. Participants included 66 male patients with NMIBC. Patients with full pathology results, NMIBC stage T1, and healthy controls were categorized as groups 1, 2, and 3, respectively. Patients were further classified into high- and low-grade groups following their pathology results. Risk classification according to the European Association of Urology (EAU) was assigned to patients with NMIBC, and associations of risk groups with serum and urine endocan levels were analyzed. An enzyme-linked immunosorbent assay was used to identify serum and urine endocan concentrations. Results. Serum endocan levels according to pathological staging were significantly higher in groups 1 and 2 than in group 3. The urine endocan level was statistically significantly higher in group 2 than in group 3 (p < 0.001). The predictive power of the urine endocan level was evaluated for its ability to predict T1 disease, revealing an area under the curve of 0.735 and a threshold of 903. The EAU classification was evaluated according to risk groups, and the urine endpoint was statistically significantly higher in the univariate analysis for the high and very high-risk groups (p = 0.034). Conclusion. Our results indicate that endocan levels hold significant promise in prognostic feature evaluation in NMIBC, particularly in the context of screening patients with hematuria.Publication Metadata only Gemcitabine-loaded chitosan nanoparticles enhanced apoptotic and ferroptotic response of gemcitabine treatment alone in the pancreatic cancer cells in vitro(Springer, 2024) Ozturk, Kivilcim; Arslan, Fatma Betul; Calis, Sema; Ulusu, Nuriye Nuray; Aydemir, Duygu; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); School of Medicine; Graduate School of Health SciencesGemcitabine (GEM) is a first-line treatment for pancreatic ductal adenocarcinoma (PDAC) patients, causing side effects and poor overall survival. Eighty percent of patients often develop resistance rapidly to GEM. Developing therapeutic approaches and increasing sensitivity to gemcitabine in PDAC has become one of the challenges in cancer research. We synthesized GEM-loaded NPs prepared with a method that combines ultrasonication and ionotropic gelation to overcome GEM-related limitations in PDAC. CFPAC-1 cells were treated with increased concentrations of GEM, empty chitosan, and GEM-loaded NPs (0.66, 1.32, 2.64, 5.32 mu g/ml) for up to 48 h. Empty chitosan NPs did not show toxicity on L929 cells. Antioxidant enzyme activities, including glucose 6-phosphate dehydrogenase (G6PD), 6-phosphogluconate dehydrogenase (6-PGD), glutathione reductase (GR), glutathione s-transferase (GST), and glutathione peroxidase (GPx), significantly reduced in GEM-loaded NPs compared to the GEM associated with increased oxidative stress, PPP, and glycolysis. Bcl-xL, NOXA/mcl-1, and Ca2+ levels significantly increased in GEM-loaded NP-administered cells compared to the GEM and control groups. In contrast, JNK, p38, STAT3, Akt, and CREB levels significantly decreased in the GEM-loaded NP group, addressing enhanced apoptotic response compared to the GEM alone. Increased ferroptosis activity in GEM-loaded NP-administered groups has been validated via decreased antioxidant enzyme activities, increased cytosolic Fe, Zn, Mg, and Mn levels, and reduced GPx activity compared to the GEM and control groups. For the first time in the literature, we showed biocompatible GEM-loaded NPs enhanced apoptotic and ferroptotic response in CFPAC-1 cells via downregulation of antioxidant, glycolysis, and PPP metabolism compared to the GEM alone.Publication Metadata only Evidence of mitophagy in lens capsule epithelial cells of patients with pseudoexfoliation syndrome(Lippincott Williams and Wilkins, 2024) N/A; Aydemir, Dilara; Sönmez, Sadi Can; Kısakürek, Zeynep Büşra; Gözel, Merve; Karslıoğlu, Melisa Zişan; Güleser, Ümit Yaşar; Şahin, Afsun; Hasanreisoğlu, Murat; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Graduate School of Health Sciences; School of Medicine; Koç University HospitalPurpose Pseudoexfoliation Syndrome (PEX) is a condition in which aberrant fibrillary protein builds up in various components of the eye and other extraocular tissues. In this study, we aim to investigate the functionality of intracellular auto-degradative machinery -especially mitophagy- and related genes and proteins in PEX. Methods Anterior lens capsules were obtained from cataracts patients with and without PEX to constitute the PEX group and age-matched controls during microincision cataracts surgery. PINK1-mediated mitophagy markers were evaluated on the transcriptional and translational level via RT-qPCR and immunohistochemistry analysis, respectively. Results The lens epithelial cells of PEX patients were characterized by significantly higher PINK1 gene expression compared to that of the controls (p<0.05). In terms of intensity of staining of expressed proteins, PINK1 (p<0.05), Parkin (p<0.01) and LC3B (p<0.01) were all statistically higher in PEX, compared to the controls. Conclusion Altered auto-degradative response -specifically mitophagy- is a component of increased oxidative stress in PEX patients. The role of this mechanism in emerging complications warrants further research.Publication Metadata only Development and psychometric analysis of care needs scale for mothers of children with congenital heart disease(Elsevier Inc., 2024) Ay, Ayse; Saridag, Kubra Nur Kabakci; Semerci, Remziye; School of NursingPurpose: This cross-sectional study aimed to create and evaluate a care needs scale for mothers of children with congenital heart disease (CHD) to determine its psychometric properties. Design and methods: This methodological research was conducted with 155 mothers whose children were diagnosed with CHD and were treated at a university hospital. The study's methodology included scale development, specialist opinions, and a pilot test. Data analysis involved descriptive statistics, exploratory and con firmatory factor analyses, and reliability assessments. Results: The 11 -item scale was created using component analysis, expert comments, and pilot testing. It was divided into two categories: Information Needs Regarding Disease and Treatment and Needs Regarding Care. The Exploratory Factor Analysis revealed a 2 -factor structure, explaining 41.5% of the variance. Reliability analysis showed reliable dimensions, and Tukey's scalability test indicated the scale requires separate dimension evaluation. The model fi t indices were obtained as CMIN/DF (72.751/41) =1.774, GFI = 0.925, IFI = 0.923, TLI = 0.893, CFI = 0.920, RMSEA = 0.071, SRMR = 0.063. The Cronbach's alpha coef ficient for subdimension 1 was 0.758, and for subdimension 2 was 0.678, indicating reliable dimensions. Conclusion: The developed scale provides a valuable tool for assessing the care needs of mothers of children with CHD, contributing to enhancing maternal support programs in pediatric cardiology clinics. Practice implications: Assessment of the care needs of mothers who have children with CHD is promising for the development of educational programs on this subject and to ensure the competence of mothers for care.Publication Metadata only The impact of the vitamin D and resveratrol administration on the stiffness and elasticity of T2DM rat aorta associated with the trace element and mineral levels(Elsevier Inc., 2024) Anapali-Aykac, Merve; Ulutin, Turgut; Komurcu-Bayrak, Evrim; Kaya-Dagistanli, Fatma; Department of Mechanical Engineering; Ulusu, Nuriye Nuray; Aydemir, Duygu; Salman, Naveed; Karimzadehkhouei, Mehrdad; Alaca, Burhanettin Erdem; Department of Mechanical Engineering; Koç University Research Center for Translational Medicine (KUTTAM) / Koç Üniversitesi Translasyonel Tıp Araştırma Merkezi (KUTTAM); Koç University Surface Science and Technology Center (KUYTAM) / Koç Üniversitesi Yüzey Teknolojileri Araştırmaları Merkezi (KUYTAM); n2STAR-Koç University Nanofabrication and Nanocharacterization Center for Scientifc and Technological Advanced Research; School of Medicine; Graduate School of Health Sciences; College of EngineeringBackground: Type 2 diabetes mellitus (T2DM) is directly associated with increased aortic stiffness, reduced aortic elasticity, and aortic dissection, which are independent risk factors for cardiovascular death. Since Vit D and resveratrol have been reported due to their cardioprotective effects, in this study, we aim to evaluate the impact of Vit D and resveratrol treatment alone or in combination on the aortic health associated with trace element and mineral levels in a high-fructose diet/streptozotocin-induced T2DM model. Methods: We investigated biomechanical changes of the aorta samples via a custom-built stretcher, where trace element and mineral levels in aorta samples were determined via inductively coupled plasma mass spectrometry (ICP-MS) following acidic microwave digestion. Results: Vitamin D treatment ameliorated the adverse effects of T2DM on aortic stiffness, aortic elasticity, and relaxation modulus in diabetic rats. Trace element and mineral levels correlated with cardiovascular homeostasis, including Fe, Cu, Zn, Se, and Na, have been regulated upon Vit D treatment in diabetic and healthy rats. On the other hand, resveratrol treatment alone or in combination with Vit D did not show any positive effects on biomechanical properties and trace element metabolism of diabetic or healthy rats, according to our data. Conclusion: Vit D can be used in T2DM patients to protect their cardiovascular health and should be considered a promising targeted therapy approach via nanoparticles to target cardiovascular diseases in the future.