Meslek Yüksekokulları
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- ItemFabrication of Al/n-GaN/p-Si/Al diodes by thermal evaporation and evaluation of effect of gamma irradiation on device properties(Elsevier, 2024-12) Olkun, Ali; Kaplan, Hüseyin Kaan; Akay, Sertan Kemal; Sarsıcı, Serhat; Erdoğan, Nursev; 414025This study investigates the impact of gamma-irradiation on the material and device properties of Al/n-GaN/p-Si/Al heterojunction diodes. GaN thin films were deposited on glass and p-Si substrates using thermal evaporation, followed by annealing at 450 degrees C. The diodes were subjected to gamma-irradiation doses of 0, 3, and 6 kGy. X-ray diffraction (XRD) measurements revealed significant structural changes, including phase transitions influenced by radiation. Electrical characteristics were assessed through current-voltage (I-V) measurements within the +/- 2 V range. Notably, the ideality factor for the annealed diodes improved from 6.60 to 4.62 and 3.85 with increased gamma-irradiation. The barrier height was determined to be 0.85 eV, and it did not exhibit a significant change upon gamma-irradiation dose. The results provided valuable insights into the response of heterojunction diodes to radiation exposure, aiding in the understanding and potential improvement of the radiation resistance of GaN-based electronic devices.
- PublicationFixation of superolateral platysma flap to the mastoid fascia: a novel isolated neck lift technique(Springer, 2024-09) Okumuş, Ayhan; 293876Background This study aimed to evaluate the utility of a novel neck lift technique based on fixation of superolateral platysma flap to the mastoid fascia in terms of postoperative aesthetic outcome and patient satisfaction within an 18-month follow-up period. Methods A total of 145 female patients who underwent isolated neck lift operation with the superolateral platysma flap technique were included. Global Aesthetic Improvement Scale (GAIS) scores (by the investigator) and the patient reported outcomes were recorded in terms of improvement in the cervicofacial angle, jowls, platysmal bands and malpositioned cervical fats, at 6 and 18 months, postoperatively. The complications were recorded at early postoperative period and at 1, 6 and 18 months, postoperatively. Results The median duration of follow-up was 18 months (range, 6–48 months). GAIS scores at 18th months, revealed exceptional improvement in the cervicofacial angle (82.8%), the jowls (93.1%), platysmal bands (93.1%) and malpositioned cervical fat (97.2%). Majority of patients were very satisfied with the treatment in terms of the aesthetic improvement. Complications involved the minor ecchymosis (17.2%) and minor skin circulatory problem (11.7%) in the early postoperative period, suture exposure (12.4%) in the postoperative 1st month, and cervical band reformation in the 6th (0.7%) and 18th (1.4%) months. Conclusion In conclusion, lateral displacement and fixation of superolateral platysma flap to the mastoid fascia seems to be a useful neck lift technique for correction of platysma- and skin-derived aging sings with minor and manageable complications, immediate return to everyday activities and a high patient satisfaction.
- ItemImpact of pre-stenting and bladder dranaige on intrapelvic pressure during retrograde intrarenal surgery(Wiley, 2024-12) Yeni, Sezgin; Kılıçarslan, Hakan; Ocakoğlu, Gökhan; Coşkun, Burhan; Çiçek, Mehmet Çağatay; Günseren, Kadir Ömür; Yavaşçaoğlu, İsmet; 278343Purpose: This study aims to assess the effect of pre-stenting and bladder drainage on intrapelvic pressure (IP) during Retrograde Intrarenal Surgery (RIRS). Methods: Eighty-five consecutive patients were prospectively enrolled and meticulously recorded in a data form. Forty-two patients meeting the inclusion criteria after applying exclusion factors. The patients were divided into two groups: Group 1 (21 patients with preoperative JJ stents) and Group 2 (21 patients without preoperative JJ stents). IP was measured during RIRS, and the impact of various factors, including pre-stenting, bladder drainage and hydronephrosis (HN) grade, on IP was analysed through univariate and multiple linear regression. Results: The perioperative mean highest IP (78 ± 18.2 mmHg vs. 110 ± 23.9 mmHg), median lowest IP (29 mmHg vs. 42 mmHg) and median overall IP (41 mmHg vs. 69 mmHg) were significantly lower in Group 1 compared to Group 2 (all p < 0.001). Multivariate analysis showed that pre-stenting and mild HN (Grade 0–1) were independent predictors of reduced IP. Conclusion: Pre-stenting led to a significant reduction in IP during RIRS, likely due to passive ureteral dilation. Additionally, bladder drainage with urethral catheter further decreased IP. These findings suggest that pre-stenting and bladder drainage should be considered as strategies to reduce IP during RIRS, potentially improving surgical outcomes.
- ItemShort-term prognostic value of the culprit-SYNTAX score in patients with acute myocardial infarction(MDPI, 2023) Peker, Tezcan; Boyraz, Bedrettin; 313898Background: The SYNergy between Percutaneous Coronary Intervention with TAXus and Cardiac Surgery (SYNTAX) score is a scoring system that helps to decide on surgery or percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (MI), and studies are showing the prognostic value of this scoring system in both MI and coronary artery disease patients undergoing PCI. In acute coronary syndrome (ACS) patients, the infarct-related artery and the complexity of the lesions are also important in terms of mortality and morbidity. Our study aimed to determine the prognostic value of the culprit vessel’s SYNTAX score (cul-SS) in patients presenting with MI. Methods: In our study, 1284 patients presenting with MI were analyzed retrospectively. The SYNTAX scores and cul-SS of the patients were calculated. In-hospital and 30-day deaths and major complications were accepted as primary outcomes. The SYNTAX scores and cul-SS were compared in terms of predicting primary outcomes. Conclusions: Major complications were observed in 36 (2.8%) patients, death in 42 (3.3%) patients, and stent thrombosis in 24 (1.9%) patients. The area under the curves for SYNTAX and cul-SS for predicting primary outcomes is 0.64 and 0.68 (p = 0.026), respectively. Cul-SS was as successful as the SYNTAX score in predicting stent thrombosis and was superior in predicting short-term death and major complications.
- ItemThe effect of being married on heart rate variability, an indicator of autonomic dysfunction: A retrospective study(Lippincott Williams & Wilkins, 2023) Akgümüş, Alkame; Balun, Ahmet; Peker, Tezcan; Boyraz, Bedrettin; 313898Heart rate variability (HRV) is a noninvasive assessment that reflects the autonomic functions of the heart and is known to be impaired in many diseases. In our study, we aimed to investigate the relationship between HRV and being married. The study included 104 patients, between the aged 20 to 40 years were included in the study. The patients were divided into 2 groups as 53 healthy married (group 1) and 51 healthy unmarried (group 2). 24-hour rhythm Holter recordings were performed on all married and unmarried patients. Group 1 had a mean age of 32 ± 5 years and 47.2% men, and group 2 had a mean age of 30 ± 5 years and 54.9% men. Standard deviation of normal to normal (SDNN) was 150 ± 40 versus 128 ± 30 (P = .003), SDNN index was 66 ± 20 versus 56 ± 12 (P = .004), the square root of the mean of the squares of the differences of the adjacent root mean square of successive differences (RMSSD) was 37 ± 10 versus 30 ± 10 (P < .001), percentage of successive R-R intervals that differ by more than 50 milliseconds (PNN50) was 13.5 ± 7 versus 8.5 ± 7 (P = .001), HF was 450 ± 270 versus 225 ± 130 (P < .001) found to be significantly less in the group 2. LF/HF ratio was 1.68 ± 0.65 versus 3.31 ± 1.56 (P < .001) found to be significantly higher in the group 2. In our study, it is possible to say that the sympathetic system effect on the heart was more dominant and the HRV was lower in the unmarried group.
- ItemThe effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position: a quasi-experimental study(Wiley, 2024-02) Yiğit Avcı, Şenay; Yılmaz, Dilek; 397256Aims: The aim of this study was to research the effect of different bed head angles on the hemodynamic parameters of intensive care patients lying in the supine position. Methods: This study was a non-randomized and non-controlled, quasiexperimental repeated measures study. The study was conducted with 50 intensive care patients aged 18 and over in a general surgery intensive care unit in Turkey. With each patient in the supine position, the bed head was raised to an angle of 0°, 20°, 30°, and 45° without a pillow, and the hemodynamic parameters of central venous pressure, systolic and diastolic blood pressure, heart rate, breathing rate, and peripheral oxygen saturation were recorded after 0 and 10 min. Results: It was found that the mean central venous pressure value measured at min 0 and 10 was higher when the intensive care patients' bed head angle was raised to 45° than when the bed head was at an angle of 0° or 20° (p < .05). It was found that the patients' other hemodynamic parameters were not affected by different bed head angles. Conclusions: It was concluded as a result of this research that in intensive care patients in the supine position, only central venous pressure was affected by bed head angle, and that central venous pressure measurement can be reliably made at a bed head angle of 30°.
- ItemThe role of advanced glycation end-product levels measured by skin autofluorescence in the development of mitral annular calcification(MDPI, 2023) Boyraz, Bedrettin; Peker, Tezcan; 313898As a person ages, mitral annular calcification develops in the mitral annulus with increasing frequency. Lipid deposition, inflammation, and aging-related degeneration have been cited as potential causes of this pathophysiology, though there is currently no conclusive evidence to support this. AGEs accumulate in tissues due to the glycation of proteins and lipids, increasing the release of proinflammatory cytokines secondary to oxidative stress through the AGE receptor. The AGE levels increase in diabetic microvascular complications and degenerative aortic valve disease. Our study was planned prospectively as a case–control study involving 94 MAC-positive patients and 94 MAC-negative patients. The demographics, echocardiographic data and AGE levels of the patients were measured and recorded using the skin autofluorescence method. AGE levels were significantly higher in the MAC-positive patient group (3.2 vs. 2.7; p < 0.001). The AGE levels were observed as an independent predictor of MAC development in a regression analysis (OR: 8.05, 95% CI: 3.74–17.33, p < 0.001). In a ROC-curve analysis, the AUC was 0.79 (95% CI: 0.72–0.85). At a cut-off value of 2.7, 79.7% sensitivity and 69.1% specificity were observed. AGE levels can be used to cheaply, easily and non-invasively identify patients at risk of developing MAC.
