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Endoscopic transorbital transconjunctival approach to the pterygopalatine fossa: anatomical cadaver study.
No full textSustainable photoredox C(sp3)–P bond formation via nitrogen-vacancy-engineered carbon nitride
No full textSelective construction of C(sp3)–P bonds remain a fundamental challenge in green chemistry due to the widespread use of transition-metals, peroxides, or stoichiometric oxidants in state-of-the-art methodologies. Here, we report a metal-free, selective and sustainable strategy for oxidative C(sp3)–P bond formation using nitrogen-vacancy-engineered carbon nitride (Nv-CN) photocatalysts. A series of Nv-CN were synthesized by thermal annealing of pristine CN under controlled temperatures and atmospheres, revealing a clear structure–defect–activity relationship that correlates nitrogen vacancies with their enhanced photocatalytic performance. Among them, cyanamide-based Nv-CN annealed at 650 °C under argon atmosphere, Nv-CN(C)-650Ar, demonstrated the highest photocatalytic activity in the photoredox C(sp3)–P bond formation, achieving up to 92% yield within 1 hour under blue LED irradiation at room temperature, outperforming previously reported photocatalytic systems. Structural analyses revealed that the superior performance of Nv-CN(C)-650Ar is closely linked to an optimized N-vacancy concentration and favorable material properties, including a highly disordered structure, increased –NHx functionalities, and a high density of paramagnetic defects. The photocatalyst also exhibits a porous architecture, large surface area, strong visible-light absorption, a narrowed bandgap, and suppressed charge recombination due to the mid-gap states. Mechanistic studies indicate a single-electron oxidation pathway mediated by superoxide radicals. Nv-CN(C)-650Ar demonstrates broad substrate scope, excellent stability, and reusability over five consecutive cycles. For the optimized model C–P bond formation on a 0.25 mmol scale, the E-factor was calculated to be E = 1.4 by excluding the recyclable solvents. This work not only fills a critical gap in green C(sp3)–P bond formation, but also introduces the vacancy-performance relation through mechanistic understanding of defect engineering in CN materials and offers a sustainable, metal-free photocatalytic strategy for C–H functionalization
Development of Pre-Pottery Neolithic architecture in the Upper Tigris region: evidence from Gre Fılla
No full textRecent excavations at Gre Fılla, located in the northern part of the Upper Tigris region in modern-day Türkiye, have revealed an architecturally diverse settlement that was occupied during much of the Pre-Pottery Neolithic (c. 9300–7500 BC). While early architecture at the site aligns with developments seen more widely in northern Mesopotamia, the typological diversity that fluoresces during the Pre-Pottery Neolithic B (c. 8800–7500 BC) has previously been under-represented in the region. Here, the author examines the evolution of the architecture uncovered at Gre Fılla, arguing that the increasing architectural complexity reflects the developing social complexity of Neolithic communities
Immobilization of Trametes versicolor Laccase Enzyme to Cu-silica Aerogel and its Decolorization of Synthetic Dyes
No full textLaccase from Trametes versicolor was immobilized on a Cu-silica aerogel carrier with a large surface area (370 m²/g). Its catalytic efficacy against various synthetic dyes was thoroughly evaluated. Under optimal immobilization conditions (25 °C, pH 4.5, 2% glutaraldehyde, 12 mg/g enzyme loading, 4 h), immobilization efficiency and activity retention reached 93%, demonstrating the effectiveness of the immobilization strategy. After 10 reuse cycles, the immobilized enzyme retained 80% of its original activity, indicating high operational durability. Additionally, the immobilized biocatalyst exhibited greater stability across a broader temperature range (up to 60 °C) and at pH 4.5 compared to the free enzyme. The kinetic data for 2,6-dimethoxyphenol (2,6-DMP) showed a Km of 0.20 mM (free enzyme: 0.10 mM) and a Vmax of 178 µmol min⁻¹ mL⁻¹ (free enzyme: 69 µmol min⁻¹ mL⁻¹). For ABTS, the immobilized system had a Km of 0.35 mM (free: 0.20 mM) and a Vmax of 278 µmol min⁻¹ mL⁻¹ (free: 500 µmol min⁻¹ mL⁻¹), indicating a change in substrate affinity after immobilization. The enhanced catalytic efficiency of the immobilized enzyme was further confirmed by dye degradation tests, which showed 95% elimination of Methylene Blue within 24 h and complete removal of Coomassie Brilliant Blue G-250 and Congo Red. This performance significantly exceeded that of the free enzyme. Therefore, Cu-silica aerogel-immobilized laccase is a strategically valuable biocatalyst with high catalytic efficiency, strong operational stability, and promising scalability, offering significant potential for industrial wastewater treatment and advanced environmental biotechnology applications
Blockchain-Enabled Water Management and Crop Optimization in Arid Regions: A Sustainable Path to Food and Energy Security – The Australian Case
No full textThis study examines the short-run effects of blockchain-enabled irrigation management in the Murray–Darling Basin (MDB), one of Australia’s most water-stressed agricultural regions. Although interest in digital water technologies has accelerated, empirical evidence on their real-world effectiveness remains scarce, leaving a substantial gap in the literature. To help address this gap, we implement a simulation-assisted difference-in-differences (DID) framework that integrates annual agricultural data (2014–2023) with a counterfactual control series generated from pre-intervention dynamics. Within this framework, the adoption of blockchain-enabled irrigation in 2019 is treated as a hypothetical intervention year created through simulation rather than an observed policy change. The results reveal a significant post-2019 decline in agricultural water use alongside a measurable increase in energy consumption attributable to blockchain-assisted monitoring. No statistically significant short-term effect is detected for crop yield, suggesting that productivity responses may require longer behavioural or agronomic adjustment periods that are not fully captured by annual observations. Overall, the findings underscore both the efficiency gains and the energy trade-offs associated with blockchain-supported irrigation systems. This study offers one of the earliest empirical assessments of blockchain applications in agricultural water management and provides policy-relevant insights for arid and semi-arid regions seeking to modernize irrigation governance
FINDIK KABUĞU KATKILI POLİLAKTİK ASİT KOMPOZİT FİLAMENT GELİŞTİRİLMESİ VE DAYANIKLILIK PERFORMANSININ ARAŞTIRILMASI
No full textBu çalışmada, Polilaktik Asit (PLA) esaslı kompozitfilamentlerin mekanik özelliklerinin iyileştirilmesi ve atık fındık kabuğunun(FK) katma değerli bir malzeme olarak değerlendirilmesi amaçlanmıştır. Bukapsamda %0 Saf PLA, % 1, 3 ve 5 oranlarında fındık kabuğu katkısı içeren PLAkompozit filamentler üretilmiş ve bu filamentlerden mekanik test numunelerihazırlanmıştır.Üretilen filamentlerden elde edilen numuneler üzerinde çekme, darbe ve eğmetestleri gerçekleştirilmiştir. Çekme ve eğme testlerinde yük–uzama eğrileriesas alınarak değerlendirme yapılmış, darbe testlerinde ise absorb edilenenerji ve darbe dayanımı değerleri incelenmiştir. Her bir katkı oranı için üçeradet numune test edilmiş ve elde edilen sonuçlar karşılaştırmalı olarak analizedilmiştir.Mekanik testsonuçlarına göre saf PLA numuneleri, çekme, darbe ve eğme testlerinde dahakararlı ve sünek bir davranış sergilemiştir. Fındık kabuğu katkısınıneklenmesiyle birlikte mekanik özelliklerde genel olarak düşüş eğilimigözlenmiş, özellikle %1 ve %5 katkı oranlarında erken kırılma ve gevrekdavranış belirginleşmiştir. %3 fındık kabuğu katkılı numunelerin ise bazımekanik özellikler açısından saf PLA ile yüksek katkı oranları arasında geçişve denge davranışı sergilediği belirlenmiştir.Mekanik testsonuçlarını mikroyapısal açıdan desteklemek amacıyla Taramalı ElektronMikroskobu (SEM) analizleri gerçekleştirilmiştir. SEM görüntülerinde, fındıkkabuğu katkı oranının artmasıyla birlikte partikül kümelenmesi, mikro boşlukoluşumu ve katkı–matris ara yüzeyinde zayıf bağlanma bölgelerinin arttığıgözlemlenmiştir. Maksimum ve minimum mekanik performans sergileyen numunelereait kırılma yüzeyleri incelendiğinde, sünek ve gevrek kırılma davranışlarınınmekanik test sonuçları ile doğrudan ilişkili olduğu ortaya konulmuştur. Eldeedilen sonuçlar, fındık kabuğu katkısının PLA kompozitlerin mekanik performansıüzerinde belirleyici bir etkiye sahip olduğunu göstermektedir.</p
İnsansız Sualtı Araçlarında Görsel Servo Tabanlı Hedef Tespiti ve Otonom Yaklaşma
No full textBu tez çalışmasında, otonom bir sualtı aracı (AUV) için kamera ve basınç sensörü verilerinin birlikte kullanıldığı, hedefe yönelim ve yörünge planlamaya yönelik bir algılama ve kontrol algoritması geliştirilmiştir. Çalışmanın amacı, sınırlı sensör altyapısına sahip bir sualtı aracının görsel ve derinlik bilgilerini kullanarak hedef nesneyi algılaması, hedefe kararlı bir şekilde yönelmesi ve belirlenen mesafede kavrama görevini gerçekleştirmesidir.Görüntü işleme aşamasında, kamera verileri üzerinde ön işleme adımları uygulanmış, HSV renk uzayında renk tabanlı segmentasyon gerçekleştirilmiş ve morfolojik işlemlerle maske iyileştirilmiştir. Hedef nesne, kontur tabanlı yöntemlerle tespit edilerek görüntü düzlemindeki konumu ve piksel tabanlı boyutu hesaplanmıştır. Bu bilgiler kullanılarak tek kameralı (monocular) mesafe kestirimi yapılmıştır. Görüntüden elde edilen yatay ve düşey sapma değerleri, aracın yönelim ve derinlik referanslarının dinamik olarak güncellenmesinde kullanılmıştır.Derinlik kontrolü, basınç sensöründen elde edilen ölçümlerle PID tabanlı bir denetleyici aracılığıyla sağlanmıştır. Yanal sürüklenme (drift) etkileri ise ardışık kamera kareleri arasında hesaplanan Farnebäck yoğun optik akış yöntemi ile tahmin edilmiş ve kontrol sinyallerine telafi edici bir bileşen olarak eklenmiştir. Geliştirilen algoritma, hedef tespiti, arama, yönelim, yaklaşma ve kavrama aşamalarını içeren durum tabanlı bir yapı içerisinde test edilmiş ve deneysel sonuçlar yöntemin sualtı ortamında uygulanabilir olduğunu göstermiştir.Anahtar Kelimeler: Durum Tabanlı Kontrol, Görüntü Tabanlı Seyrüsefer, Otonom Sualtı Aracı, Sualtı Robotları, Yörünge Planlama.This thesis develops a central, target-oriented orientation and planning system for autonomous underwater vehicles (AUVs) using camera and pressure sensor data. The aim of the study is to visually and depth-wise expand a controlled underwater vehicle, detect the target object, steer it stably towards the target, and achieve the segment objective from the recorded distance.In the image processing stage, preprocessing steps were applied to the camera data, color-based segmentation was performed in the HSV color space, and masking was improved with morphological operations. The position of the target object in the image plane and its pixel-based size were calculated by detecting it with a contour system. The single-camera (monocular) distances formed from this information were maintained. Vertical and vertical deviation values obtained from the image were used to dynamically update the details of the vehicle and depth references. Depth control is maintained by a PID-based controller with measurements obtained from pressures. Lateral drag effects were estimated using the Farnebäck dense optical data method, which calculates data between successive camera frames and rapidly incorporates them into the control signals. The method was tested within a case-based framework encompassing development, target acquisition, search, refinement, approach, and baseline phases, and comprehensive results demonstrated its applicability in underwater environments.Keywords: State-Based Control, Vision-Based Navigation, Autonomous Underwater Vehicle (AUV), Underwater Robots, Trajectory Planning.</p
Sakaguchi type functions defined by q-Bernoulli numbers
No full textThis study uses a q-derivative operator and q-Bernoulli numbers to establish the subclass SBq,λs,bF0 of Sakaguchi type functions. We obtained constraints for the initial coefficients |a2| and |a3| through our analysis, providing insight into the characteristics and behavior of functions in this subclass. Furthermore, we derive the Fekete-Szegö inequality that is peculiar to this class, along with a number of corollaries that expand on our results and enhance our comprehension of their implications