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Comprehensive genome analysis of Planococcus sp. S3-L1 isolated from Horseshoe Island in Antarctica reveals its biotechnological potential
No full textThis study explores the biotechnological potential of Planococcus strain S3-L1, isolated from Horseshoe Island in Antarctica during the 6th Turkish Antarctic Expedition in 2022. Marine bacteria inhabiting polar environments play essential roles in ecosystem dynamics and biogeochemical cycles, largely due to their unique adaptations. The Planococcus genus, noted for its halotolerance and ability to thrive in cold environments, has garnered interest for its capability to produce bioactive metabolites, support bioremediation, and facilitate various industrial processes. In this research, Planococcus sp. S3-L1 was isolated and underwent 16S rRNA and wholegenome analysis, revealing a close genetic affinity with Planococcus kocurii and Planococcus faecalis. Genomic analysis identified genes responsible for carotenoid pigment production and aromatic compound degradation, underscoring its potential in environmental remediation and low-temperature pigment production. Furthermore, quorum-quenching enzymes suggest that S3-L1 could serve as an antimicrobial agent. These findings show that Planococcus sp. S3-L1 is a promising candidate for biotechnological applications, particularly within polar marine environments, where its cold adaptation and metabolic diversity offer potential benefits in aquaculture, bioremediation, and the synthesis of commercially valuable compounds
Pregnenolone carbamate derivatives as selective cholinesterase inhibitors: a comprehensive evaluation exploring their interactions with DNA and human serum albumin.
No full textPregnenolone-carbamate derivatives were synthesized and evaluated as potential multifunctional agents with cholinesterase inhibitory and neuroprotective properties. Among them, P3, P5, and P9 exhibited the most promising profiles and were subjected to integrated spectroscopic, biochemical, and computational analyses. Inhibition assays revealed selective acetylcholinesterase (AChE) inhibition by P3 (IC50 = 0.11 μM), butyrylcholinesterase inhibition (BuChE) selectivity for P5 (IC50 = 0.47 μM), and dual inhibition by P9. Fluorescence and UV–vis studies indicated minor groove binding to DNA with log Kapp values around 5.85, while static quenching with human serum albumin (HSA) was observed, with log KA values up to 2.25. Docking studies supported these findings, showing favorable binding energies for DNA (–8.6 kcal/mol) and HSA (–9.7 kcal/mol), and predicted localization within the DNA minor groove and Sudlow sites on HSA. Cytotoxicity assays on HT22 cells indicated high viability (> 75% at 40 µM), suggesting a favorable safety margin. These results offer a molecular-level understanding of the pharmacodynamic and pharmacokinetic properties of these compounds and support their potential for further in vivo evaluation.Kocaeli Üniversitesi FBA‐2023‐346
Collapse of a steel space truss roof due to rainwater and ponding effects
No full textInadequate drainage systems and ponding effects pose risks in long-span roof structures. This study investigates the collapse of a double-layer grid system roof of a terminal building after heavy rainfall due to rainwater accumulation and ponding effects. The terminal roof, supported by reinforced concrete columns, had long spans and cantilevered sections. To investigate the cause of the collapse, this paper presents a comprehensive collapse analysis by performing linear and nonlinear finite-element analyses and ponding analyses considering geometric nonlinearity. The recently developed program, TrussImp3D, was enhanced in this study to capture geometric and ponding nonlinearities, has been validated through comparisons with previously published analytical results. These comparisons demonstrate that the analysis model is both efficient and accurate in representing the behavior of roofs under ponding conditions leading to collapse. The results show that the rainwater load accumulated at the cantilever end due to an inadequate drainage system, and the ponding effect played a critical role in the collapse
Navigating emotional and physical well-being: How organizational structure and climate influence travel agency employees' musculoskeletal discomfort through emotional exhaustion
No full textDrawing on the conservation of resource theory, this study investigates the impact of organizational structure and climate on employees' musculoskeletal discomfort mediated by emotional exhaustion. Data were gathered from employees working in travel agencies in Turkmenistan. The results indicate that an effective organizational structure and climate have a negative significant effect on employees' emotional exhaustion and musculoskeletal discomfort. Moreover, the findings indicated that emotional exhaustion has a positive significant effect on employees' self-reported musculoskeletal discomfort. Furthermore, the results highlighted the mediating role of emotional exhaustion in the interrelationship between organizational structure and climate and employees' musculoskeletal discomfort
Improvement of self-healing performance in thermoplastic matrix polymer composite materials
No full textKendi kendini iyileştirebilen polimer sistemleri, mikro düzeyde gelişen çatlakların tespiti ve onarımı sayesinde malzemelerin kullanım ömrünü artıran, sürdürülebilir ve akıllı malzeme tasarımlarına olanak tanıyan yenilikçi yapılardır. Bu sistemlerde en yaygın kullanılan yöntemlerden biri olan kapsülleme tekniği, çatlak oluşumu sırasında kırılan kapsüllerden salınan iyileştirici ajanların, çatlak yüzeyinde reaksiyona girerek malzemeyi onarmasını hedeflemektedir. Kapsülleme işlemi, hem iyileştirici ajanı çevresel etkilerden korumak hem de kontrollü salınım sağlanması açısından kritik öneme sahiptir. Bu tez çalışması kapsamında, polipropilen (PP) esaslı içi boş makrokapsüller geliştirilmiş ve bu kapsüller hem polistiren (PS) hem de PP matrisleri içerisinde dağıtılarak iyileştirme performansları karşılaştırılmıştır. Kompozit numuneler üzerinde üç nokta eğilme, basma ve çekme testleri uygulanarak mekanik özelliklerin iyileşme öncesi ve sonrası karşılaştırması yapılmıştır. Ayrıca, oluşan çatlak ilerleme yönü üzerindeki etkileri mikroskobik analizlerle desteklenmiştir. Buna ek olarak, reaktif termoplastik akrilik reçine ve benzoil peroksit içeren çekirdek yapısıyla, üre-formaldehit (UF) kabuk temelli mikrokapsüller in-situ polimerizasyon yöntemiyle sentezlenmiştir. Kapsül üretimi ve stabilitesi, çekirdek bileşimi, matris yapısının iyileşme verimliliği mekanik ve karakterizasyon testleriyle değerlendirilmiştir.Self-healing polymer systems are innovative structures that increase the lifetime of materials by detecting and repairing micro-level cracks, enabling sustainable and smart material designs. The encapsulation technique, one of the most widely used methods in these systems, aims to repair the material by reacting on the crack surface with the healing agents released from the capsules that break during crack formation. The encapsulation process is critical in terms of both protecting the healing agent from environmental effects and ensuring controlled release. In this thesis, polypropylene (PP) based hollow macrocapsules were developed and dispersed in both polystyrene (PS) and PP matrices and their healing performances were compared. Three-point bending, compression and tensile tests were performed on the composite specimens to compare the mechanical properties before and after curing. In addition, the effects on the direction of crack propagation were supported by microscopic analysis. In addition, urea-formaldehyde (UF) shell-based microcapsules with a core structure containing reactive thermoplastic acrylic resin and benzoyl peroxide were synthesized by in-situ polymerization. Capsule production and stability, core composition, healing efficiency of the matrix structure were evaluated by mechanical and characterization tests
Combined effect of recycled tire steel fiber and blast furnace slag on the mechanical performance of 3d printable concrete
No full textThis study investigated the effects of waste steel fiber and high-volume blast furnace slag (BFS) substitution on the mechanical and physical properties of three-dimensional printable concrete (3DPC) to improve its environmental performance. BFS was substituted for cement at 0%, 25%, 50%, and 75% by volume. Waste steel fibers were added to the mixtures at three lengths (5, 10, and 15 mm) and two volumetric ratios (0.5% and 1.0%). Twenty-eight mixtures were optimized based on extrudability, buildability, and shape stability criteria. Parameters such as compressive and flexural strength, surface moisture content, and drying shrinkage were evaluated. The results showed that using up to 0.5% waste steel fibers increased compressive strength by up to 23%, but decreased it to a level of 1%. Fiber reinforcement improved the flexural strength of all blends by up to 53% at both ages, regardless of fiber ratio or length. Increasing the BFS substitution rate generally increased surface moisture however, this value decreased in mixtures containing 75% BFS and silica fume. Furthermore, using steel fibers and in-creasing fiber length significantly improved the drying shrinkage performance of the mixtures
Reinforcement of polylactic acid parts manufactured additively by material extrusion method by adding monofilament polyester mesh interlayers
No full textThis study investigates the use of monofilament polyester mesh interlayers to enhance the mechanical performance of PLA parts produced by fused filament fabrication (FFF). Through tensile and bending tests conducted on samples manufactured with varying numbers of reinforcement layers (0, 1, 2) and extrusion temperatures (210 degrees C, 230 degrees C, 250 degrees C), it was determined that extrusion temperature significantly influences mechanical properties; low temperatures led to insufficient adhesion issues, while increasing temperatures generally improved strength. It was also found that polyester mesh reinforcement particularly increased tensile strength at low temperatures, but this effect diminished or became negative at higher temperatures. In conclusion, this research suggests that the incorporation of reinforcement mesh interlayers in FFF offers a promising hybrid approach to improve mechanical properties with proper parameter selection
A comparative evaluation of the effects of prolonged 24-hour fasting/feeding and peripheral ghrelin administration on adiponectin, cortisol, and proinflammatory cytokine levels in rats
No full textGünümüzde obezite, tip 2 diyabet ve kardiyovasküler hastalıklar gibi metabolik bozuklukların önemli bir nedeni olarak karşımıza çıkmaktadır. Bu hastalıklarla mücadelede aralıklı oruç (intermittent fasting, IF) gibi diyet yaklaşımları, kilo kaybının ötesinde metabolik sağlığı iyileştirme potansiyeli ile dikkat çekmektedir. Bu çalışmada, 24 saatlik aralıklı oruç (Alternatif Gün Açlığı, ADF) ve periferik ghrelin uygulamasının farelerde adiponektin, kortizol ve proinflamatuar sitokin düzeyleri üzerindeki etkileri karşılaştırmalı olarak incelenmiştir. Çalışmada 21 adet 10 haftalık erkek Bulb-C faresi üç gruba ayrılmıştır: kontrol grubu (serbest beslenme), aralıklı oruç grubu (24 saat açlık/24 saat beslenme) ve ghrelin enjeksiyon grubu (günlük 1 µmol/kg intraperitoneal ghrelin). İki hafta boyunca uygulanan protokoller sonucunda, grupların plazma ghrelin, adiponektin, kortizol, TNF-α, IL-6 ve IL-1β düzeyleri ELISA yöntemiyle ölçülmüş ve istatistiksel olarak analiz edilmiştir. Bulgulara göre, aralıklı oruç grubunda ghrelin düzeyleri birinci haftada kontrol grubuna kıyasla anlamlı şekilde artmış (%40, p < 0.01), bu artış ikinci haftada daha da belirginleşmiştir (p < 0.001). Adiponektin düzeyleri ise aralıklı oruç grubunda her iki haftada da kontrol grubuna göre yüksek bulunmuş (%35-40, p < 0.001), ancak ghrelin enjeksiyon grubunda bu artış gözlenmemiştir. Kortizol düzeyleri, aralıklı oruç grubunda ilk haftada yükselmiş (p < 0.001), ancak ikinci haftada adaptif bir düşüş göstermiştir (p < 0.001). Proinflamatuar sitokinler (TNF-α, IL-6, IL-1β) aralıklı oruç grubunda belirgin şekilde azalırken (%35-45, p < 0.01), ghrelin enjeksiyon grubunda benzer bir etki görülmemiştir. Bu çalışma, aralıklı orucun ghrelin ve kortizol artışına rağmen adiponektin yükselişi ve inflamatuar yanıtta azalma ile metabolik adaptasyon sağladığını, ancak ekzojen ghrelin uygulamasının bu kompleks etkiyi taklit edemediğini ortaya koymuştur. Bulgular, aralıklı orucun metabolik yararlarının yalnızca ghrelin artışına bağlı olmadığını, daha kapsamlı hormonal ve hücresel mekanizmaları içerdiğini göstermektedir.Today, metabolic disorders such as obesity, type 2 diabetes, and cardiovascular diseases are recognized as significant health concerns. In combating these conditions, dietary approaches like intermittent fasting (IF) have gained attention due to their potential to improve metabolic health beyond just weight loss. This study comparatively examines the effects of 24-hour intermittent fasting (Alternate-Day Fasting, ADF) and peripheral ghrelin administration on adiponectin, cortisol, and proinflammatory cytokine levels in mice. The study involved 21 ten-week-old male Bulb-C mice divided into three groups: a control group (ad libitum feeding), an intermittent fasting group (24-hour fasting/24-hour feeding), and a ghrelin injection group (daily 1 µmol/kg intraperitoneal ghrelin). Following a two-week protocol, plasma levels of ghrelin, adiponectin, cortisol, TNF-α, IL-6, and IL-1β were measured using ELISA and statistically analyzed. The findings revealed that ghrelin levels in the intermittent fasting group increased significantly in the first week compared to the control group (40%, p < 0.01), with a more pronounced rise in the second week (p < 0.001). Adiponectin levels were higher in the intermittent fasting group in both weeks (35-40%, p < 0.001), but no such increase was observed in the ghrelin injection group. Cortisol levels rose in the intermittent fasting group during the first week (p < 0.001) but showed an adaptive decline in the second week (p < 0.001). Proinflammatory cytokines (TNF-α, IL-6, IL-1β) decreased significantly in the intermittent fasting group (35-45%, p < 0.01), whereas no similar effect was seen in the ghrelin injection group. This study demonstrates that intermittent fasting induces metabolic adaptation through increased adiponectin and reduced inflammatory response, despite elevated ghrelin and cortisol levels, whereas exogenous ghrelin administration fails to replicate these complex effects. The findings suggest that the metabolic benefits of intermittent fasting are not solely dependent on ghrelin elevation but involve broader hormonal and cellular mechanisms
Taxation of crypto assets in Turkey: Comparative analysis of legal framework and applications
No full textBu tez, dijitalleşen küresel ekonomiyle birlikte önem kazanan kripto varlıkların vergisel konumunu Türkiye örneği üzerinden incelemekte ve mevcut yasal düzenlemeleri uluslararası uygulamalarla karşılaştırarak kapsamlı bir değerlendirme sunmaktadır. Çalışmada, kripto varlıkların tarihsel gelişimi, teknolojik temelleri ve ekonomik işlevleri açıklanmış; token türleri ile NFT’ler gibi yenilikçi dijital varlık sınıfları ayrıntılı biçimde ele alınmıştır. Blokzincir teknolojisinin teorik ve teknik yönleri incelenerek bu yapının vergi uygulamaları bakımından ortaya çıkardığı fırsatlar ve karşılaştığı zorluklar analiz edilmiştir. Uluslararası düzeyde Avrupa Birliği, IMF, OECD ve FATF gibi kuruluşların düzenleyici yaklaşımları ile Almanya, Fransa, ABD, İngiltere, Japonya ve Güney Kore başta olmak üzere 25’in üzerinde ülkenin kripto varlık vergilendirme sistemleri incelenmiş; bu çerçevede ülkeler arasındaki farklılıklar ve ortak eğilimler karşılaştırmalı olarak ortaya konmuştur. Türkiye açısından ise Hazine ve Maliye Bakanlığı, MASAK, BDDK, SPK ve TCMB gibi kurumların düzenleme ve uygulamaları değerlendirilmiş; kripto varlık işlemlerinin gelir vergisi, KDV, kurumlar vergisi, damga vergisi, BSMV ve veraset ve intikal vergisi kapsamındaki hukuki niteliği tartışılmıştır. Sonuç olarak, Türkiye’nin mevcut vergisel yaklaşımının uluslararası uygulamalara göre parçalı ve belirsiz bir yapıya sahip olduğu; bu nedenle kripto varlıklara yönelik açık, bütüncül ve şeffaf bir vergi rejiminin oluşturulmasının zorunlu hale geldiği sonucuna ulaşılmıştır. Çalışma, hem hukuki belirliliğin artırılması hem de uluslararası uyumun güçlendirilmesi açısından Türkiye’deki politika yapıcılar için yol gösterici bir çerçeve sunmaktadır.This thesis examines the tax position of crypto assets, which have gained increasing importance in the digitalized global economy, through the case of Turkey and in comparison with international practice. The study first explains the historical development, technological foundations and economic functions of crypto assets. It then elaborates on innovative digital asset classes such as different token types and NFTs within a coherent conceptual framework. The theoretical and technical aspects of blockchain technology are analyzed with a particular focus on the opportunities it creates and the challenges it poses for tax law and tax administration. Methodologically, the thesis adopts a comparative legal approach. It analyzes the regulatory and tax perspectives of international organizations such as the European Union, the IMF, the OECD and the FATF, together with the crypto asset taxation regimes of more than twenty-five countries, including Germany, France, the United States, the United Kingdom, Japan and South Korea. In the Turkish context, the study evaluates the regulations and practices of the Ministry of Treasury and Finance, MASAK, the BRSA, the CMB and the Central Bank. It discusses the legal nature of crypto asset transactions under the Income Tax Law, the VAT system, Corporate Tax, Stamp Duty, the Banking and Insurance Transactions Tax and Inheritance and Transfer Tax. The thesis concludes that Turkey’s current tax approach to crypto assets remains fragmented and ambiguous when compared to international practices. Therefore, establishing a clear, comprehensive and transparent tax regime for crypto assets has become imperative. The study offers a guiding framework for policymakers in Turkey to enhance both legal certainty and international compliance in the taxation of crypto assets
Predictive value of TGF-β1 and SMAD-7 expression at diagnosis for treatment response in low-risk myelodysplastic syndrome
No full textMyelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disease. Supportive treatments, such as erythropoiesis-stimulating agents (ESAs), are commonly used in patients with low-risk MDS. This study aimed to retrospectively assess the impact of bone marrow Mothers against decapentaplegic homolog 7 (SMAD-7) and transforming growth factor beta 1 (TGF-β1) protein expression on prognosis and response to ESA treatment in patients with low-risk MDS. We retrospectively analyzed patients diagnosed with low-risk MDS at the adult hematology department of Bursa Uludağ University Hospital. A total of 56 patients classified as low or very low risk were included in the study. Immunohistochemical analysis of bone marrow specimens at diagnosis showed that only five patients (9.8%) exhibited low SMAD-7 staining, while 51 patients (90.2%) showed no staining. Regarding TGF-β1 staining, 18 patients (32.1%) demonstrated moderate to high staining, whereas 38 patients (67.9%) exhibited low (36/38) or no staining (2/38). A statistically significant correlation was found between TGF-β1 staining levels and ESA treatment administration (P = 0.011). Additionally, a significant relationship was observed between lower erythropoietin (EPO) levels and moderate to high TGF-β1 staining (P = 0.04). However, when TGF-β1stainingstatuswascomparedwithfirst-andthird-monthtreatmentresponsesinpatientsreceiving ESA therapy, no significant difference was detected between groups. These findings suggest that while TGF-β1alonemaynotbe sufficient to predict ESA treatment response, additional parameters related to the TGF-β/SMAD pathway should be considered. Strong TGF-β1 staining, alongside EPO levels, may influence the decision to initiate ESA therapy