İstanbul Sağlık ve Teknoloji Üniversitesi Kurumsal Akademik Arşivi
DSpace@İSTÜN, Üniversite mensupları tarafından doğrudan ve dolaylı olarak yayınlanan; kitap, makale, tez, bildiri, rapor, araştırma verisi gibi tüm akademik kaynakları uluslararası standartlarda dijital ortamda depolar, Üniversitenin akademik performansını izlemeye aracılık eder, kaynakları uzun süreli saklar ve telif haklarına uygun olarak Açık Erişime sunar.
Güncel Gönderiler
Does lip change following premolar extraction differ in patients with high and normal vertical growth patterns?
(Galenos Publishing House, 2026) Erdem, Buket; Başal, Ece; Emir, Büşra
Objective: To evaluate the relationship between incisor retraction and upper and lower lip repositioning in patients with high and normal vertical growth patterns (NVP), and to assess whether vertical growth pattern influences soft tissue changes following extraction treatments. Methods: Pre- and post-treatment lateral cephalograms of 79 patients who underwent extraction of two or four first premolars were analyzed. Patients were divided into a [high vertical pattern (HVP); Frankfort-mandibular plane angle (FMA) >30°, n=49] and a NVP; 22< FMA ≤30°, n=30) group. Horizontal and vertical changes in the lips, labiomental fold, and lip strain were measured, and correlations between these changes and incisor movements were assessed. Results: Upper lip retraction was greater in the HVP group (2.86 mm, p<0.05) than in the NVP group (1.97 mm, not significant). Upper lip height decreased significantly in both groups, with a slightly greater decrease in the NVP group (p<0.001). Upper lip strain decreased in both groups, especially in the HVP group (p<0.001). Incisor retraction was strongly correlated with upper-lip changes in both groups, and with lower-lip and labiomental-fold repositioning in the NVP group. Conclusion: Soft tissue response to incisor retraction varies with vertical growth pattern, with greater upper lip retraction in HVP patients. Vertical growth patterns should be considered for optimal soft tissue outcomes.
Thermo, pH, and ionic-strength-responsive MPEG–PEI copolymer: A reversible soluble–insoluble support promotes glucoamylase immobilization and sustainable catalysis
(Elsevier, 2026) Haykır, Nazife Işık; Kosaoğlu, Hacim; Tuncel, Ali; Çelebi, Serdar Suut
Glucoamylase (GA) plays a crucial role in the saccharification of starch and other related oligo saccharides in the food and fermentation industries. The construction of an immobilized GA using a reversibly soluble/insoluble methoxy polyethylene glycol–polyethyleneimine (MPEG–PEI) copolymer synthesized via carbodiimide chemistry is presented in this work. Various MPEG:GA ratios were assessed to optimize enzyme loading and catalytic activity. Immobilized GA retained up to 12.6% of its theoretical activity but demonstrated excellent operational stability and reusability. Substrate-assisted immobilization, using maltose and maltodextrin to protect GA's active site during synthesis of the carrier, significantly improved enzyme activity—up to a 3.1- fold increase compared to the unprotected system. While maltodextrin yielded higher initial activity, maltose with a lower initial activity offered better long-term stability, maintaining 70% of its initial activity even after 11 reuse cycles. Kinetic analysis using the Lambert-W function revealed increased Km for the immobilized enzyme, indicating decreased substrate affinity due to a possible conformational change on the immobilized form of GA. While a minor decrease in conversion efficiency was observed under high initial substrate concentrations in practice, the reversibly soluble/insoluble MPEG–PEI copolymer exhibited effective thermo-responsive char acteristics, enabling the sustained and recyclable use of GA in starch hydrolysis and offering considerable potential for other future biotechnological applications.
Evaluation of muscle oxygenation by functional near-infrared spectroscopy in patients with myasthenia gravis during rest and exercise
(Turkish Neuropsychiatric Society, 2026) Coşkun Semiz, Ebru; Alökten, Merve; Karakulak, Ece Zeynep; Aysal, Fikret; Hanoğlu, Lütfü
Introduction: Myasthenia gravis (MG) is an autoimmune disease that is caused by autoantibodies targeting the neuromuscular junction. A few studies in the literature show that MG may negatively affect muscle metabolism. However, no current study investigates MG pathophysiology’s effect on muscle oxygenation. In this study, we aimed to investigate the difference in muscle oxygenation in MG disease and to evaluate its clinical Pathophysiological implications. Methods: 19 MG patients and 19 age, gender and body mass index (BMI) matched healthy controls participated in the study. Functional near-infrared spectroscopy (fNIRS) recordings were recorded from six channels over the biceps brachii muscles during the rhythmic elbow flexion-extension task. Results: It was observed that oxygenated-hemoglobin (HbO) (p = 0.008) and total hemoglobin (HbT) (p = 0.017) values during exercise were significantly lower in MG patients in the motor point of the biceps brachii muscle. In addition, at rest, deoxygenated-hemoglobin (HbR) levels were significantly lower in patients (p<0.05) in the motor point and the lateral region of the biceps brachii muscles. Additionally, a difference is observed in fNIRS values between the moderate-severe MG group and healthy controls. Also, a negative correlation was observed between exercise-state HbO and rest-state HbR values and disease severity (p<0.05). Conclusion: MG patients show deterioration in muscle oxygenation values during exercise and rest. Oxygenation values show significant differences in disease severity and negatively correlate with disease severity. Based on these findings, MG disease may affect muscle oxygenation and can be monitored by fNIRS.
Sharps injuries among nursing staff: A qualitative study
(SAGE Publications, 2026) Aydoğdu, Ana Luiza Ferreira
Background: Injuries involving members of the nursing team are not uncommon, with sharps-related incidents being among the most frequent. Previous studies have focused on quantitative outcomes or on healthcare professionals in general, leaving a gap in understanding the subjective experiences and perspectives of nursing staff. This study aimed to explore the opinions and experiences of nursing staff regarding sharps injuries, with the goal of identifying contributing factors, gaps in current prevention strategies, and opportunities to improve occupational safety and injury-prevention practices within healthcare settings. Methods: This qualitative study used a descriptive phenomenological approach and included 38 nursing staff from various regions of Brazil. Participants responded to open-ended online questions between July 26 and September 11, 2025. Findings: Themes emerged: (1) the moment when the injuries occur, (2) factors that trigger the injuries, (3) the period following the injuries, and (4) strategies adopted to prevent new injuries. Twelve subthemes were identified.Conclusions/Applications to Practice:The study addresses a highly relevant issue in healthcare, as nursing staff need to prioritize their own health while caring for others. Although it does not present findings different from previous research regarding the occurrence of such injuries, its importance may lie precisely in highlighting results that remain unchanged. The study also shows that nurses often internalize blame for occupational injuries, viewing them as personal failures rather than system issues. It highlights the need for rigorous monitoring, ongoing training, consistent safety materials, and encouragement of incident reporting to strengthen collective safety and promote a positive safety culture.
Effect of agricultural waste-derived biomethanol use on the performance and emission characteristics of a diesel engine
(Pen Academic Publishing Journals, 2026) Tunçer, Erdal
This study investigates the effects of wheat straw-derived biomethanol–diesel blends on the performance and emission characteristics of a diesel engine. Four fuel blends were tested: pure diesel (D100) and biomethanol blends at volumetric ratios of 5%, 10%, and 15% (B5, B10, B15). Experiments were conducted on a single-cylinder diesel engine under four load conditions (25%, 50%, 75%, and 100%). The results show that although the lower heating value of biomethanol increased specific fuel consumption (from 308 g/kWh to 346 g/kWh at full load), its high oxygen content and latent heat of vaporization significantly improved key emission parameters. Under full load, the B15 blend reduced exhaust gas temperature by 29 °C, soot emissions by 25%, and CO emissions by approximately 21% compared to D100. Conversely, nitrogen oxide (NOx) emissions increased from 2165 ppm to 2420 ppm, attributed to the ignition delay characteristics of biomethanol. Overall, blending biomethanol with diesel is an effective strategy for reducing soot and CO emissions; however, further optimization is required to address the trade-off between NOx emissions and fuel consumption.
