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Impact of Laparoscopic Sleeve Gastrectomy on Pulmonary Arterial Stiffness and Right Ventricular Function in Obese Patients
No full textIntroduction Pulmonary hypertension (PH) is a serious condition associated with high morbidity and mortality, with obesity identified as a significant risk factor. Pulmonary arterial stiffness (PAS) is an early marker of PH, often preceding clinical symptoms. While laparoscopic sleeve gastrectomy (LSG) has been shown to improve various cardiac parameters in obese patients, its impact on PAS and right ventricular (RV) function in the absence of PH remains unclear. This study investigates the effects of LSG on PAS and RV function in obese patients without pre-existing PH. Methods A cohort of 54 patients with obesity who underwent LSG between January and June 2023 at the University hospital was prospectively studied. Patients were evaluated preoperatively and six months postoperatively using comprehensive echocardiographic assessments. Key parameters measured included tricuspid annular systolic velocity (TAS), tricuspid regurgitation velocity (TRV), pulmonary flow acceleration time (PFAT), pulmonary artery velocity, and PAS. Statistical analyses were conducted using paired t-tests and the Wilcoxon signed-rank test. Results Significant improvements were observed in several echocardiographic and hemodynamic parameters post-LSG. PAS showed a notable reduction from 2.44 +/- 0.68 preoperatively to 1.74 +/- 0.32 postoperatively (p 0.001). Additionally, significant decreases were observed in TRV (2.00 +/- 0.30 m/sec to 1.79 +/- 0.40 m/sec, p = 0.025) and systolic pulmonary artery pressure (SPAP) (21.28 +/- 4.69 mmHg to 18.36 +/- 5.28 mmHg, p = 0.025). Improvements in RV function were indicated by an increase in tricuspid annular plane systolic excursion (TAPSE) from 17.68 +/- 4.17 mm preoperatively to 21.18 +/- 3.53 mm postoperatively (p 0.001). Conclusions LSG significantly reduces PAS and improves RV function in obese patients, even in the absence of PH. These findings suggest that LSG may offer protective effects on pulmonary vascular health, highlighting its potential as a therapeutic intervention for reducing PH risk in obese patients. Further research is warranted to explore the long-term cardiovascular benefits of LSG in diverse populations
Sports Participation and Ankle Injury Prevalence Among Medical School Students
No full textPurpose: The aim of this study is to evaluate the prevalence of ankle injuries and the tendency of medical students to participate in sports, and the effect of medical school preparation and study process on participation in sports. Material and methods: A cross-sectional descriptive study was conducted among medical students at Pamukkale University Faculty of Medicine. Data were collected using an online questionnaire covering aspects of sports participation before and after medical school, types and frequency of sports played, and history of ankle injuries. Statistical analysis was performed to examine changes in sports participation and injury prevalence. Results: A total of 253 students took part in the study. Of these, 135 (53.4%) participated in sports before medical school, with volleyball (28%), football (17%) and basketball (17%) being the most common. Ankle injuries were particularly common in football (50%), basketball (33%) and volleyball (21%). After starting medical school, 48 of the students reduced or stopped their sports activities, citing academic workload as the main reason. However, 46 students started sports activities espacially fitness. Conclusion: The study highlights a significant decline in sports participation during the university entrance exam among medical students due to academic pressure, with a notable prevalence of ankle injuries in high-impact sports. During medical school education, there is an increasing tendency to engage in fitness-style sports with a lower risk of injury. © 2025, Pamukkale University. All rights reserved
Can Waste Heat of a Thermal Power Plant Be a Key for Absorption Cooling Systems
No full textWaste Heat Driven Absorption Cooling Systems (WHDACS) can be simply defined as a cooling system which uses thermal fluid couples such as LiBr-H2O or NH3-H2O to decrease the temperature of selected space via waste heat usage in generator. This study focuses on the use waste heat that is discharged from thermal power plants in order to meet heat load of generator used in absorption cooling systems. Yatagan thermal power plant that has 3 discharged waste heat units with 145 MWt per unit. 172°C steam temperature and 1.18bar steam pressure is examined as a case study. LiBr-H2O ACS is designed and optimum working parameters of system elements are determined by both considering single effect of the parameter and interacted effect of the temperature and concentration ratio parameters on Coefficient of Performance (COP) and Exergetic Coefficient of Performance (EPC) of the system. Optimum values of T1, T2, T4. T5, Xw, Xs for single effect are found as; T1=100°C. T2=40°C. T4=10°C for max COP 4°C for max EPC. T5=70°C. Xw=45% and Xs=63.41%. Optimum values for interacted independent parameters are found as 100°C for T1. 46.86°C for T2. 9.996°C for T4 and 70°C for T5. 45% for Xw. 60% for Xs by using Nelder-Mead Method. It is observed that the waste heat discharged from Yatagan Thermal Power Plant is convenient to establish an absorption cooling system. Cooling potential of WHDACS is calculated 84MWt approximately for each waste heat unit. © 2025, Sakarya University. All rights reserved
Fotonik kristal yapılarında düşük simetrinin öz-kolimasyona etkisi
No full textBu tez çalışması Pamukkale Üniversitesi Bilimsel Araştırma Projeleri
Koordinasyon Birimi tarafından 2021FEBE040 nolu proje ve 100/2000 YÖK
Doktora Burs programı tarafından desteklenmiştir. Bu çalışma sırasında
Pamukkale Üniversitesi Malzeme Fiziği Simülasyon Laboratuvarının
imkanlarından yararlanılmıştır.Fotonik kristallerin optik iletimdeki, özellikle yön kontrolü ve ışık
sınırlamasındaki avantajları, yeni nesil opto-elektronik cihazlardaki kritik rollerini
vurgulamaktadır. Gelecekteki fotonik uygulamalarda ışığı etkili bir şekilde kontrol
etmek için yenilikçi kristal yapılara olan ihtiyaç arttıkça, hegzagonal örgü tabanlı
fotonik kristaller çeşitli açılarda öz-kolimasyon etkileri oluşturma kabiliyetleri
nedeniyle önemli bir çözüm olarak ortaya çıkmaktadır. Bu tez çalışmasında,
hegzagonal örgü yapısına sahip fotonik kristallerin öz-kolimasyon etkisi, birim
hücrenin simetrisinin tüm yönlerde ayarlanmasıyla elde edildi. Önerilen yapının
opto-geometrik parametreleri optimize edilmiş ve öz-kolimasyon etkisi, grup hız
dağılımı (GVD) ile üçüncü dereceden dağılım (TOD) özellikleri kullanılarak analiz
edildi.
Tek bir dielektrik çubuk içeren düşük simetrili hegzagonal örgü fotonik
kristal yapısının, %2,4 band genişliği ile 0,652 ila 0,668 normalize frekans
aralığında her yönde öz-kolimasyon sergilediği belirlendi. Simetrinin daha fazla
kırılması ile iki dielektrik çubuk içeren düşük simetrili bir gruba geçiş, %6,5'lik özkolimasyon
band genişliğine ve iki ayrı frekans bandında mükemmel lineer eş
frekans konturlarının oluşumu ile sonuçlandı. Özellikle, 4. enine manyetik (TM)
band, 0,616 ila 0,652 normalize frekans aralığında tüm yönlerde öz-kolimasyon
etkileri gösterirken, 5. TM bandı, 0,712 ila 0,760 aralığında aynı etkiyi
göstermektedir. Ek olarak, iki dielektrik çubuğun aynı kırılma indisine ve çubuk
çapına sahip dikdörtgen fotonik tellerle değiştirilmesiyle elde edilen hibrit fotonik
kristal yapısı önerildi. Bu hibrit yapı, %11,7 band genişliğiyle her yönde özkolimasyon
etkileri sergilemekte ve sıfıra yakın GVD ve TOD değerleri sağlayarak
potansiyel üretim toleranslarına karşı yüksek dayanıklılık sunmaktadır. Elde edilen
sonuçlar, yeni nesil ışık manipülasyonuna dayalı uygulamalarda kullanım
potansiyeli olan fotonik kristal tasarımlara yenilikler sunmaktadır.The advantages of photonic crystals in optical transmission, particularly in
directional control and light confinement, underscore their critical role in
optoelectronic devices. As the demand for novel crystal structures capable of
effectively manipulating light increases, hexagonal lattice-based photonic crystals
have emerged as a promising solution due to their ability to induce self-collimation
at various angles. In this thesis, the self-collimation effect in hexagonal lattice
photonic crystals is achieved by systematically adjusting the symmetry of the unit
cell. The opto-geometric parameters of the proposed structure are optimized, and
the self-collimation effect is analyzed through group velocity dispersion (GVD) and
third-order dispersion (TOD) characteristics.
It is determined that a low-symmetry hexagonal lattice photonic crystal with
a single dielectric rod exhibits self-collimation in all directions within the
normalized frequency range of 0.652 to 0.668, corresponding to a bandwidth of
2.4%. Further symmetry reduction, achieved by introducing a second dielectric rod,
leads to an increased self-collimation bandwidth of 6.5% and the formation of welldefined
linear equal-frequency contours in two distinct frequency bands.
Specifically, the fourth transverse magnetic (TM) band exhibits self-collimation
within the normalized frequency range of 0.616 to 0.652, while the fifth TM band
demonstrates this effect within 0.712 to 0.760. Additionally, a hybrid photonic
crystal structure is proposed, replacing the two dielectric rods with rectangular
photonic wires of the same refractive index and rod diameter. This hybrid structure
exhibits self-collimation in all directions with an expanded bandwidth of 11.7% and
provides near-zero GVD and TOD values, enhancing robustness against potential
fabrication tolerances. The findings presented in this study contribute to the
advancement of photonic crystal design, with potential applications in nextgeneration
light manipulation technologies
Unravelling the Influence of Service Failure on Negative Customer Engagement: the Moderating Role of Service Recovery
No full textThis study examines negative customer engagement through the influences of service failure, service recovery, (dis)satisfaction with service recovery, and perceived severity of service failure by adopting a mixed-method approach. Based on the qualitative study which identified the most frequent service failures and recoveries in hotels, a scenario-based experiment was designed to test the proposed relationships. The results show that service failure impacts the perceived severity of service failure but is contingent upon the type of service recovery. (Dis)satisfaction with service recovery, which is influenced by perceived severity of service failure determines negative customer engagement. Moreover, the relationships among the perceived severity of service failure, (dis)satisfaction with service recovery, and disengaged behaviour are curvilinear. © 2025 Elsevier Lt
Critical Success Factors for Government Crisis Communication Over Social Media in Emergency Management
No full textSynthesis and Characterization of Ag Doped Cuo Nanoparticles With Different Sizes and Investigation of Their Anticancer Activity
No full textIn this work, Ag-doped CuO nanoparticles with different sizes were synthesized using co-precipitation method at two different reaction temperatures. The crystallinity, particle size, and morphology of the nanoparticles were characterized by XRD, SEM, and EDS analysis. The monoclinic structures of Ag-doped CuO nanoparticles were determined by using XRD analysis, indicating their high crystallinity and the absence of secondary phases. The spherical and disk-like morphology and purity of the nanoparticles were confirmed through FESEM-EDS analysis with an average particle size of 448 nm and 240 nm for CuO@Ag-NP1 (NP1) and CuO@Ag-NP2 (NP2), respectively. The anti-cancer effect of NP1 and NP2 in U87 and LN18 glioblastoma (GBM) cell lines has been examined. GBM, a grade IV astrocytoma, is the most aggressive form of primary brain tumor and currently has no cure, highlighting the urgent need for new treatment strategies. Our findings suggested that both nanoparticles induced cell viability and mitochondrial membrane potential loss, however because NP2 has smaller particle size compared to NP1, it exerted a higher toxic effect following 50 mu g/ml in U87 and LN18 cell lines.Open access funding provided by the Scientific and Technological Research Council of Turkiye (TUB ; Idot;TAK).Scientific and Technological Research Council of Turkiye (TUBIdot;TAK
The Mediating Effects of Mental Fatigue and Mindfulness on the Relationship Between Physical Activity and Quality of Life in Young Adults: Structural Equation Modeling
No full textCan Gur, Ganime/0000-0002-6013-257XObjectives: This study explores the impact of physical activity on young adults' quality of life, with a novel focus on the mediating roles of mental fatigue and mindfulness. Methods: A cross-sectional study was conducted with undergraduate students studying at a university in Western Turkey (May-June 2024). Data were collected online using validated scales, including the Physical Activity Scale-2 (PAS-2), Short Form Health Survey (SF-12), State Mindfulness Scale (SMS), and Mental Fatigue Scale (MFS). Structural equation modeling (SEM) was employed to assess mediation effects. Results: The structural model also exhibits a good fit, with chi(2) (339) = 627.937, chi(2)/df = 1.852, p 0.001, RMSEA = 0.045, SRMR = 0.052, CFI = 0.911, GFI = 0.901, TLI = 0.900, and IFI = 0.912. Mental fatigue significantly mediated the relationship between physical activity and quality of life (beta = 0.108; p = 0.030), while mindfulness did not show a significant mediating role. Physical activity had significant positive direct (beta = 0.151; p = 0.010), indirect (beta = 0.108; p = 0.030), and total (beta = 0.259; p = 0.008) effects on quality of life. Conclusion: The results of the study highlight the importance of physical activity in enhancing young adults' quality of life, particularly by helping to reduce mental fatigue. These results emphasize the need for strategies that promote physical activity as a way to combat mental fatigue and enhance overall well-being
Experimental and Theoretical Investigation of Structural, Spectroscopic, and Physicochemical Properties of Azobenzene-Based Compound
No full textAzobenzene-based compounds have recently attracted a lot of attention in innovative potential applications due to their photoresponsive properties and functions. Herein, we present a comprehensive theoretical and experimental investigation of the changes in the physical and chemical properties of an azobenzene-based compound under UV-light irradiation. In this context, first a novel monomer containing fluorine-substituted photoactive azobenzene and electroactive carbazole namely (E)-9-(4-(4-((4-(trifluoromethyl)phenyl)diazenyl)phenoxy)butyl)-9H-carbazole (coded as Cz-AzoCF(3)) was synthesized. Theoretical studies were conducted using Density functional theory (DFT) and Time-Dependent DFT (TD-DFT) methods, utilizing the functionals of B3LYP and CAM-B3LYP (Becke-3-Lee-Yang-Parr) with the basis set of 6-31 G (d, p). The changes in structural, electronic, and vibrational properties induced by light were analyzed through a combination of theoretical and experimental approaches, utilizing techniques such as IR, NMR, and UV-vis spectroscopy. In conclusion, a high correlation was observed between experimental and calculated data. This remarkable agreement not only provides robust and guiding information on molecular design and characterization but also paves the way for new studies. From this perspective, experimental and theoretical studies are complementary to each other.TUBITAK [119Z618]; Pamukkale University [2021FEBE063]This study was supported by TUBITAK (Grant No: 119Z618) and Pamukkale University (Grant No: 2021FEBE063)
Gastric Acid Challenge: Mechanical Proficiency and Surface Gloss of Tooth-Colored Restorative Materials
No full textBackgroundTo evaluate surface microhardness, roughness, and gloss changes of tooth-colored restorative materials [a direct composite (G-aenial A'Chord), an indirect composite (Gradia Plus), an ormocer (Admira Fusion), a giomer (Beautifil II), and an alkasite (Cention N)] after exposure to simulated gastric acid.MethodsA total of 110 disc-shaped specimens (22 discs of each material) were prepared using silicone molds (8 mmx2 mm) and exposed to either gastric acid or artificial saliva (control). Surface roughness (Ra), gloss (GU), and microhardness (VHN) were measured at baseline and after 96-hour of immersion in the solutions and the respective changes (triangle Ra, triangle GU, triangle VHN) were calculated. Intergroup comparisons were performed using ANOVA (Tukey post hoc) or Kruskal-Wallis tests (Bonferroni correction). Independent samples t-test or Mann-Whitney U test was used for comparisons of each material across immersion media, while paired t-test was applied for time-dependent analyses.ResultsIn the gastric acid medium, changes in all parameters led to significant differences among restorative materials, while in the artificial saliva medium, significant differences were observed in triangle VHN and triangle GU. The statistically significant difference between immersion media was observed in both triangle VHN and triangle Ra values for the giomer group, and in only triangle VHN values for the alkasite and indirect composite groups. In the gastric acid medium, the decrease in VHN and GU values was significant across all subgroups, while the increase in Ra was statistically significant only in the giomer and alkasite groups.ConclusionsWhile the giomer group exhibited the most significant changes in roughness and microhardness following exposure to gastric acid, all tested materials executed clinically admissible results regarding surface gloss.Clinical trial numberNot applicable