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Engineering 3D-printed soft electronics: Roles of conducting polymers and conductive hydrogels in biosensor design
No full textThree-dimensional (3D) printing has revolutionized the fabrication of advanced sensing platforms by integrating diverse materials into complex, functional architectures. This review presents a comprehensive comparison of two primary classes of printable conductive materials, conducting polymers (CPs) and conducting hydrogels (CHs), within the context of sensor and bioelectronic device fabrication. It details the roles of 3D printing technologies such as direct ink writing (DIW), digital light processing (DLP), and extrusion methods in tailoring the performance of soft, conductive structures, highlighting how CPs offer superior electrical conductivity and structural integrity, whereas CHs provide enhanced biocompatibility, flexibility, and adaptability to soft environments. The review discusses key material characteristics including conductivity, printability, mechanical robustness, and biocompatibility, alongside application-specific performance in wearable electronics, biosensing, and implantable systems. By critically assessing trade-offs and synergies of each material class, this work aims to guide future developments in soft and functional sensing devices via additive manufacturing. © 2025 Elsevier B.V., All rights reserved
Environmental drivers of lionfish catch efficiency in trammel net fisheries in the Southwest coasts of Türkiye
No full textInvasive species pose significant challenges to marine ecosystems worldwide, with lionfish among the most prominent. Lionfish (Pterois miles and Pterois volitans) began invading the northwestern Atlantic in the 1980s and rapidly expanded throughout the region. In the Mediterranean, they were first recorded off Israel in 1991, followed by a new invasion event in Lebanon in 2012. Since then, the species has spread rapidly across the eastern Mediterranean and progressively westward, raising concerns over ecological and socio-economic impacts, building on lessons from their invasion in the Atlantic and far beyond. In Türkiye, P. miles has rapidly expanded along the southern coasts, triggering ecological concerns and driving interest in scalable removal strategies. This study evaluates the catch efficiency of thick trammel nets, a widely used gear type in small-scale fisheries in relation to gear configuration and environmental factors. Between 2022 and 2024, 41 thick trammel net deployments were conducted at depths of 16–62.5 m using nets with varying mesh sizes (72, 90, 100 mm) and twine thicknesses (210/9 and 210/12 denier). The nets were soaked for 12 h and 50 min to 23 h. All fish were identified and weighed onboard. Lionfish accounted for over 50 % of total catch, reflecting their high regional abundance. Catch per unit effort was positively correlated with soak time and water temperature, and negatively with mesh size and longitude. Generalized Additive Models indicated peak catch per unit effort at 24–28 °C, with optimal performance around 80–90 mm mesh size and longer soak durations. While twine thickness had a limited effect on catch per unit effort, thicker lines were associated with safer handling of lionfish and may increase fisher willingness to target this species. The findings suggest that modest gear adjustments—combined with favorable environmental timing—can enhance lionfish removals without altering core fishing practices. These results support the integration of gear-based solutions into market-driven invasive species control strategies, with potential socio-economic benefits for small-scale fisheries communities. © 2025 Elsevier B.V., All rights reserved
Comparative luminescence and Judd–Ofelt analysis of Eu3+-doped Ca2GdVO6 and Sr2GdVO6 phosphors for red-emitting applications
No full textIn this study, Eu3+-activated Ca2Gd1?xVO6 and Sr2Gd1?xVO6 (x = 0–30 mol%) red-emitting phosphors were synthesized via a conventional solid-state reaction route and systematically characterized to assess the effect of A-site variation on their structural and photoluminescence properties. X-ray diffraction results confirmed the single phase formation of monoclinic-Ca2GdVO6 (P21/n) and monoclinic-Sr2GdVO6 (P2/m) structures, as further corroborated by full Rietveld refinements that yielded low-residual fits and reliable lattice parameters. SEM micrographs revealed similar grain morphologies with marginal differences in average grain sizes. Photoluminescence excitation spectra exhibited a broad charge transfer band (CTB) centered near 256 nm, attributed to O2? ? Eu3+ transitions, along with sharp f–f transitions and characteristic Gd3+ absorptions. Emission spectra under blue excitation (?ex = 467 nm) demonstrated dominant 5D0 ? 7F2 electric dipole transitions, with higher asymmetry ratios observed in the Ca-based system, indicating a more distorted local environment. Judd–Ofelt (JO) analysis further confirmed this distinction through elevated ?2 parameters, particularly at low doping levels. The quantum efficiencies (?QE) calculated using the Judd–Ofelt formalism were 99.56 % and 78.05 % for the most luminescent Ca-based and Sr-based samples, respectively, while the experimentally measured IQE/EQE values were 79.82 %/41.69 % (Ca-based) and 65.58 %/36.66 % (Sr-based). Additionally, colorimetric evaluation revealed that both phosphor systems emitted warm reddish light with high color purity (up to ?85 % for Ca-based and ?96 % for Sr-based) and low correlated color temperature (CCT ? 1600–2500 K), suitable for warm-white LED and display applications. These findings highlight the tunable nature of Eu3+-activated vanadate perovskites via A-site engineering, enabling their use in solid-state lighting, displays, and optical security. © 2025 Elsevier B.V., All rights reserved
Comparative Analysis of Various Trawl Codend Selectivity for Red Mullet (Mullus barbatus) and Whiting (Merlangius merlangus) in the Black Sea
No full textThe aim of this study was to estimate the selectivity of 40 mm (40D) and 44 mm (44D) diamond mesh size, 40 mm square (40S), and turned (40T) mesh codend for red mullet (Mullus barbatus) and whiting (Merlangius merlangus). Samples were collected from two locations in the western Black Sea during 21-28 July 2020 using covered codend method was used in experiment. For red mullet, the mean fifty-percent retention length (L50) values for 40D, 40S, 40T and 44D were estimated at 8.55 (8.02-8.93) cm, 12.04 (11.03-12.80) cm, 11.46 (10.11-11.99) and 13.23 (12.69-13.71) cm respectively. L50 values of 40D, 40S, 40T and 44D were determined as 10.06 (8.59-12.58) cm, 15.61 (14.74-16.24) cm, 15.45 (14.48-15.54) cm, 13.56 (12.63-14.11) cm for whiting, respectively. The estimated L50 of the commercially used 40D codend was lower than the Minimum Conservation Reference Size (MCRS) for red mullet and whiting (13 cm). All tested experimental codends improved the size selectivity of the studied species compared with the legally allowed minimum mesh size (40 mm). In addition, the discard rate for red mullet using the 40D codend, which is commonly employed in the Black Sea, was found to be 97.90%. The implementation of 40S codends could reduce this rate to approximately 84.57%. Similarly, for whiting, the discard rate decreased from approximately 74.09% to 59.03%, depending on the tested experimental codends. The size selectivity and exploitation pattern of codends for red mullet and whiting could be improved by simply changing to square (40S) orturning(40T) meshes, based on MCRS. Also, the present study provides the scientific foundation for the regulation concerning the increase of the codend mesh size of diamond 44 mm in trawl fishing in the Black Sea, which is scheduled for implementation in 2028.Istanbul University BAP Scientific Research Projects Coordination Unit [FDK-2018-30202]This study was supported by Istanbul University BAP Scientific Research Projects Coordination Unit. Project number: FDK-2018-30202. Authors would like to thank the anonymous referees for their suggestions and comments
Classification of color images of leathers tanned with different vegetable tannins by convolution neural network
No full textThe leather industry is a multifaceted domain where the tanning process plays a pivotal role in determining the final characteristics of the product. Among various methods, vegetable tanning is an age-old technique yet sustainable that utilizes natural tannins extracted from various plant sources to transform raw animal hides into durable and versatile leather. The ability to accurately classify leathers tanned with different vegetable tannins is of paramount importance for quality control, product authentication, and optimizing the tanning process itself. However, traditional classification approaches based on physical, biochemical, or microscopic analyses are often subjective, time-consuming, and prone to inconsistencies. In response to these limitations, this study proposes a deep learning-based classification approach using Convolutional Neural Networks (CNNs) to automatically differentiate between color images of leathers tanned with four different types of vegetable tannins. A dataset comprising 144 leather images was developed, with 80% used for training and 20% for testing. The CNN model achieved promising results, with precision, recall, and F1-score values of 88%, 87%, and 86% on the training set, and 77%, 78%, and 77% on the test set, respectively. These findings demonstrate the potential of CNN-based methods as efficient and objective tools for leather tannin classification in industrial applications
Comparative Analysis of Various Trawl Codend Selectivity for Red Mullet (Mullus barbatus) and Whiting (Merlangius merlangus) in the Black Sea
No full textThe aim of this study was to estimate the selectivity of 40 mm (40D) and 44 mm (44D) diamond mesh size, 40 mm square (40S), and turned (40T) mesh codend for red mullet (Mullus barbatus) and whiting (Merlangius merlangus). Samples were collected from two locations in the western Black Sea during 21-28 July 2020 using covered codend method was used in experiment. For red mullet, the mean fifty-percent retention length (L50) values for 40D, 40S, 40T and 44D were estimated at 8.55 (8.02–8.93) cm, 12.04 (11.03–12.80) cm, 11.46 (10.11–11.99) and 13.23 (12.69–13.71) cm respectively. L50 values of 40D, 40S, 40T and 44D were determined as 10.06 (8.59–12.58) cm, 15.61 (14.74–16.24) cm, 15.45 (14.48–15.54) cm, 13.56 (12.63–14.11) cm for whiting, respectively. The estimated L50 of the commercially used 40D codend was lower than the Minimum Conservation Reference Size (MCRS) for red mullet and whiting (13 cm). All tested experimental codends improved the size selectivity of the studied species compared with the legally allowed minimum mesh size (40 mm). In addition, the discard rate for red mullet using the 40D codend, which is commonly employed in the Black Sea, was found to be 97.90%. The implementation of 40S codends could reduce this rate to approximately 84.57%. Similarly, for whiting, the discard rate decreased from approximately 74.09% to 59.03%, depending on the tested experimental codends. The size selectivity and exploitation pattern of codends for red mullet and whiting could be improved by simply changing to square (40S) or turning (40T) meshes, based on MCRS. Also, the present study provides the scientific foundation for the regulation concerning the increase of the codend mesh size of diamond 44 mm in trawl fishing in the Black Sea, which is scheduled for implementation in 2028. © 2025 Elsevier B.V., All rights reserved
Falsely elevated FSH levels due to assay interference: a case-based approach
No full textLaboratory results are important to patient diagnosis and management. Immunoassay interference can lead to misleading results and inappropriate clinical decisions. We present the case of a 30-year-old woman with secondary amenorrhea and unexpectedly elevated follicle-stimulating hormone (FSH) levels that did not align with her clinical findings, including normal ovarian reserve and spontaneous return of menstruation. Suspecting assay interference, a comprehensive evaluation was undertaken, including serial dilution, polyethylene glycol (PEG) precipitation, heterophile antibody blocking, and method comparison studies. Non-linear serial dilution results and markedly low FSH recovery after PEG precipitation (7.09 %) supported the presence of macro-FSH or interfering antibodies. Heterophile blocking tube tests showed no significant effect, making heterophile interference less likely. However, method comparison revealed discordant FSH values across platforms, with only Advia Centaur XP reporting within the reference range. Notably, Advia Centaur used sheep-derived detecting antibodies, unlike Abott Architect i 2000 and Roche Elecsys, which both used mouse-derived antibodies. This led to the hypothesis of an autoantibody against mouse-derived detecting antibodies as the source of interference. This case underscores the importance of close collaboration between clinicians and laboratory professionals to identify assay interference, ensuring accurate diagnosis and avoiding unnecessary interventions
Derin ve transfer öğrenme yöntemleri kullanılarak otomatik göğüs röntgeni raporlama
No full textGöğüs röntgeni, hekimler tarafından en sık başvurulan radyolojik tetkiklerden biridir. Ancak, özellikle hasta yoğunluğunun yüksek olduğu sağlık kurumlarında bu görüntülerin yorumlanması ve raporlanması, radyoloji birimlerinin iş yükünü önemli ölçüde artırmaktadır. Bu tez çalışması kapsamında, göğüs röntgenlerinden otomatik rapor üretimini hedefleyen üç aşamalı AURORA-CXR modeli geliştirilmiştir. Modelin ilk aşamasında, görüntü kalitesini artırmaya yönelik olarak histogram eşitleme, gamma düzeltme ve bulanık mantık temelli tekniklerden yararlanan adaptif bir ön işleme yaklaşımı tasarlanmıştır. İkinci aşamada, tıbbi görüntülerden anlamlı özniteliklerin çıkarılması için Evrişimli Sinir Ağı (CNN) tabanlı derin öğrenme mimarileri kullanılmıştır. Son aşamada ise, elde edilen özniteliklerin tıbbi raporlara dönüştürülmesi amacıyla transformer tabanlı bir dil modeli oluşturulmuştur. Buna ek olarak, rapor üretim sürecinde ortaya çıkan aday raporları klinik ve doğal dil metriklerine göre yeniden değerlendiren çok kanallı bir reranking mekanizması kullanılmış, böylece sistemin doğruluk ve güvenilirliği artırılmıştır. Bu çalışmanın temel katkıları, görüntü kalitesini yükseltmek üzere adaptif ön işleme tekniklerinin ve rapor doğruluğunu artırmak üzere çok kanallı yeniden sıralama algoritmalarının bir arada kullanılmasıdır. Yapılan deneysel çalışmalar, özellikle klinik metriklerde anlamlı iyileşmeler sağlandığını ortaya koymuştur.Chest X-ray is one of the most frequently utilized radiological examinations by physicians. However, especially in healthcare institutions with high patient density, the interpretation and reporting of these images significantly increase the workload of radiology departments. Within the scope of this dissertation, a three-stage model named AURORACXR was developed with the aim of automatic report generation from chest Xrays. In the first stage, an adaptive preprocessing approach was designed, utilizing techniques such as histogram equalization, gamma correction, and fuzzy logicbased methods to improve image quality. In the second stage, Convolutional Neural Network (CNN) based deep learning architectures were employed to extract meaningful features from medical images. In the final stage, a transformerbased language model was constructed to convert the extracted features into medical reports. Additionally, a multi-channel reranking mechanism was used to re-evaluate the candidate reports generated during the reporting process according to clinical and natural language metrics, which enhances the accuracy and reliability of the system. The main contributions of this study are the integration of adaptive preprocessing techniques to improve image quality and the use of multi-channel reranking algorithms to increase report accuracy. Experimental analyses demonstrated that the proposed approach provided significant improvements, particularly in clinical metrics
Biyogaz tesislerinin mekânsal modellemesinde Coğrafi Bilgi Sistemleri kullanımı
No full textBu tez çalışmasında, İzmir ili Menemen ilçesinde hayvansal atıklara dayalı biyogaz üretim potansiyelinin belirlenmesi ve bu potansiyelin ekolojik ve ekonomik kriterler doğrultusunda kurulacak biyogaz tesislerinin uygun alanlara yönlendirilmesi amacıyla Coğrafi Bilgi Sistemleri (CBS) kullanılarak mekânsal bir analiz gerçekleştirilmiştir. Biyogaz tesislerinin yer seçimi, hem sürdürülebilir enerji üretimini desteklemek hem de doğal ve kültürel değerleri korumak açısından kritik bir öneme sahiptir. Menemen ilçesi sınırları içerisinde 2023 yılı itibariyle yaklaşık 31.135 büyükbaş, 58.861 küçükbaş ve 921.206 kanatlı hayvan bulunmaktadır. Çalışmada, hayvansal atıkların biyogaz eşdeğeri olan metan (CH₄) potansiyelleri hesaplanmış, mahalle düzeyinde değerlendirilmiştir. Bununla birlikte koruma alanları, tarım arazileri, kıyı alanları, su kaynakları gibi çevresel kısıtlayıcı ekolojik kriterler dikkate alınmış “korumacı” ve “sakınmacı” yaklaşım ile tampon bölgeler belirlenmiştir. Ayrıca Network analizi ile hayvan atıklarının tesislere ulaştırılabilirliği değerlendirilmiş, enerji nakil hatlarına yakınlık gibi ekonomik unsurlar göz önünde bulundurulmuştur. Elde edilen sonuçlara göre, Menemen ilçesinde biyogaz üretimi potansiyeli en yüksek mahalleler Ulukent, Yahşelli, Çukurköy ve İnönü’dür. Ancak bu bölgelerdeki kültürel miras alanları ve endemik türlerin yaşam alanları gibi ekolojik değerler, tesis yer seçimini sınırlandırmaktadır. Çalışma sonucunda, biyogaz potansiyeli ile çevresel sürdürülebilirlik ilkeleri birlikte değerlendirildiğinde, özellikle Çukurköy, Hasanlar, Yahşelli, Türkelli ve Ulukent mahallelerinin belirli bölümlerinin tesis kurulumu açısından uygun olduğu ortaya konmuştur. Bu bütüncül yaklaşım, yalnızca enerji üretimi değil, aynı zamanda doğal kaynakların korunması açısından da literatüre önemli bir katkı sunmaktadır.In this thesis study, a spatial analysis was conducted using Geographic Information Systems (GIS) to determine the biogas production potential based on animal waste in the Menemen district of İzmir province and to identify suitable areas for the establishment of biogas plants in accordance with ecological and economic criteria. Site selection for biogas facilities is of critical importance not only to support sustainable energy production but also to preserve natural and cultural assets. As of 2023, the Menemen district hosts approximately 31,135 cattle, 58,861 small ruminants, and 921,206 poultry. In this study, the methane (CH₄) potential equivalent of animal waste was calculated and evaluated at the neighborhood level. In addition, ecological constraints such as protected areas, agricultural lands, coastal zones, and water resources were taken into account. Buffer zones were established through a “precautionary” and “conservationoriented” approach. Furthermore, a network analysis was applied to evaluate the accessibility of animal waste to potential plant sites, taking into consideration economic factors such as proximity to energy transmission lines. The findings indicate that the neighborhoods of Ulukent, Yahşelli, Çukurköy, and İnönü have the highest biogas production potential in Menemen. However, ecological values such as cultural heritage sites, and habitats of endemic species in these areas limit the options for site selection. As a result of the study, when biogas potential is assessed alongside environmental sustainability principles, specific parts of Çukurköy, Hasanlar, Yahşelli, Türkelli, and Ulukent neighborhoods are identified as suitable for plant establishment. This holistic approach contributes significantly to the literature not only in terms of energy production but also for the conservation of natural resources
Mikroplastik kirliliğinin toprağın fiziko-kimyasal ve mikrobiyolojik özellikleri üzerine etkisi
No full textPlastik atıkların zaman içerisinde daha küçük parçalara ayrılmasıyla ortaya çıkan ve 5 mm'den küçük boyutlara sahip olan mikroplastikler, çevresel ortamlara yayılarak toprağa da ulaşmakta ve toprak sistemlerinin fiziksel, kimyasal ve mikrobiyolojik özelliklerini etkileyebilmektedir. Tarımda kullanılan plastiklerin bozunması, mikroplastiklerin topraklara geçişinde en belirgin nedenlerden biridir. Bu çalışma, tarımsal üretimde sıklıkla tercih edilen polipropilen (PP) taban örtüleri ile düşük yoğunluklu polietilen (PE) fidan torbalarının parçalanmasıyla ortaya çıkan mikroplastik kalıntılarının, toprak özellikleri üzerindeki potansiyel etkilerini incelemeyi amaçlamaktadır. Araştırmada, kimyasal yapıları farklı iki plastik malç materyali (Polietilen, PE ve Polipropilen, PP) üç farklı dozda (%1, %2 ve %3) toprağa uygulanmıştır. Sivri biber bitkisinin yetiştirildiği saksı denemesi 3 tekerrürlü olarak tesadüf parselleri deneme desenine göre yürütülmüştür. Toplam 3,5 ay süren deneme sonunda hasat edilen bitkilerde biyokütle ağırlıkları ve bitki besin madde içerikleri saptanmıştır. Saksı topraklarında ise bazı fiziksel, kimyasal ve mikrobiyolojik analizler yürütülmüştür. Ayrıca toprağa uygulanan mikroplastiklerin bakteri ve fungus taksonomik gruplarında yaptığı etkiyi incelemek için metagenomik analiz yapılmıştır. PP ve PE mikroplastik uygulamalarının toprağın fiziksel özellikleri üzerindeki etkisi net bir şekilde ortaya çıkmıştır. Her iki mikroplastik çeşidi, istatistiksel olarak da önemli olan toprağın hacim ağırlığı parametresi üzerinde, kontrol grubu ile kıyaslandığında azaltıcı bir etki gösterirken, benzer şekilde kontrol grubuna göre PP’in toprağın maksimum su tutma kapasitesini artırdığı fakat PE’nin ise azaltıcı yönde bir etkisi olduğu tespit edilmiştir. Mikroplastik uygulamaları ile toprağın pH değerinde kontrole oranla bir miktar azalma kaydedilirken, Kontrol grubunda %0,65 olarak belirlenen organik madde miktarı, PP-D2 dozunda %2,18’e yükselmiş ve bu durum kontrol grubuna kıyasla yaklaşık %235 oranında bir artışa sebep olmuştur. Çalışmada kullanılan PP ve PE mikroplastiklerinin toprağın bazı mikrobiyolojik özellikleri üzerine de etkili olduğu ortaya çıkarılmıştır. İstatistiksel açıdan önemli olan toprağın dehidrogenaz enzim aktivitesinde PP-D1 dozunda %15’lik bir düşüş kaydedilirken, alkalin fosfataz enzim aktivitesi değerlerinde ise PE-D3 dozunda %8 değerinde bir azalma meydana gelmiştir. Mikroplastiklerin toprak solunumu üzerindeki etkisi de mikroplastiğin çeşidine göre değişiklik göstermiştir. Gerek toprağın ve gerekse bitkinin makro ve mikro besin madde içeriği mikroplastiklerin çeşit ve dozuna bağlı olarak farklı etkilere sahip olmuştur. Metagenomik analizlere göre, deneme topraklarında 10 bakteri ve 5 fungus şubesi tanımlanmıştır. Topraklarda en yüksek orana sahip bakteri şubesi Proteobacteria olmuş ve mikroplastik uygulanan topraklarda kontrole oranla bu bakterilerin oranında bir azalma meydana gelmiştir. Topraklarda en yüksek orana sahip fungus şubesi ise Ascomycota olmuş ve mikroplastik uygulanmış topraklarda kontrole oranla bu şubeye ait fungusların da oransal olarak azaldığı tespit edilmiştir.Microplastics, which are particles smaller than 5 mm formed through the degradation of larger plastic materials, can enter environmental systems and subsequently reach the soil, where they influence various properties including physical, chemical, and microbiological characteristics. One of the primary pathways through which microplastics are introduced into soil is the degradation of plastics used in agricultural practices. This study aimed to investigate the potential effects of microplastic residues derived from commonly used polypropylene (PP) ground covers and low-density polyethylene (PE) seedling bags on soil properties. In this study, two plastic mulch materials with different chemical structures— polyethylene (PE) and polypropylene (PP)—were applied to the soil at three different concentrations (1%, 2%, and 3%). A pot experiment using long green pepper (Capsicum annuum) was conducted in a randomized plot design with three replicates. At the end of the 3.5-month trial period, biomass weights and plant nutrient contents of the harvested plants were determined. Additionally, various physical, chemical, and microbiological analyses were performed on the pot soils. Furthermore, metagenomic analysis was carried out to investigate the effects of the applied microplastics on the taxonomic composition of bacterial and fungal communities in the soil. The effects of PP and PE microplastic applications on the physical properties of the soil were clearly revealed. Both types of microplastics showed a decreasing effect on the bulk density parameter of the soil, which was also statistically significant, when compared with the control group. Similarly, while PP increased the maximum water holding capacity of the soil compared to the control group, PE was found to have a decreasing effect. With microplastic applications, a slight decrease in soil pH was recorded compared to the control. The organic matter content, which was determined as 0.65% in the control group, increased to 2.18% at the PP-D2 dose, resulting in approximately a 235% increase compared to the control group. It was also revealed that the PP and PE microplastics used in the study had an effect on certain microbiological properties of the soil. While a 15% decrease was recorded at the PP-D1 dose in soil dehydrogenase enzyme activity, which was statistically significant, an 8% decrease was observed in alkaline phosphatase enzyme activity at the PE-D3 dose. The effect of microplastics on soil respiration also varied depending on the type of microplastic. Both the macro- and micronutrient content of the soil and plants were affected differently depending on the type and dose of microplastics. According to metagenomic analyses, 10 bacterial and 5 fungal phyla were identified in the experimental soils. The most abundant bacterial phylum in the soils was Proteobacteria, and their proportion decreased in soils treated with microplastics compared to the control. The most abundant fungal phylum in the soils was Ascomycota, and the proportion of fungi belonging to this phylum was also found to decrease in soils treated with microplastics compared to the control