PubMed İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/397
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Article Parametric Study on the Behavior of CFRP-Strengthened Reinforced Concrete Deep Beams with Cut Circular Web Openings in Shear Spans(Nature Portfolio, 2026-02-17) Yagmur, ErenWeb openings in reinforced concrete deep beams are often necessary for functional purposes but substantially reduce structural performance. Carbon fiber-reinforced polymer (CFRP) strengthening is commonly employed to mitigate these effects. Previous studies typically examined openings in regions without stirrups or assumed closed stirrup configurations, overlooking the frequent stirrup damage that occurs in practice due to the high shear reinforcement in deep beams. In this study, three specimens from a prior experimental program were modeled in ABAQUS, and the numerical results were validated against experimental data. Openings of varying diameters were introduced by cutting reinforcements, and the beams were subsequently strengthened with CFRP laminates, and a parametric study was conducted. Results showed that increasing opening diameter markedly reduces load-carrying capacity and energy absoption, while thicker CFRP laminates partially restore performance. For example, a 300 mm opening in a 500 mm high unstrengthened beam reduced load capacity by 56% and energy absorption by 87%. Even when the opening diameter was less than one-third of the beam height, 1.8 mm CFRP laminates provided only limited improvement. Deep beam performance was strongly influenced by web opening size, and the effectiveness of CFRP strengthening was limited when stirrup integrity was compromised.Article Measuring Disaster Resilience in MENA Countries and Its Impact on Disaster Losses(Nature Portfolio, 2025-12-08) Demir, Abdullah; Dincer, Ali Ersin; Dincer, Nazire NergizDisaster resilience is a protective feature aimed at reducing the effects of natural disaster events and losses resulting from these events. This study develops a Disaster Resilience Index (DRI) for MENA countries to assess resilience across ten dimensions, including economic, social, institutional, infrastructural, and environmental factors. Unlike most prior studies, which focus on individual countries or use narrower sets of indicators, this study provides a multi-country, region-specific framework tailored to MENA's socio-economic and environmental heterogeneity. The index integrates geospatial data on disaster risk from geographic information systems (GIS) and a natural hazard risk dimension. Validation using disaster-related fatalities, supported by a dual PCA-based sensitivity analysis, confirms the robustness of the DRI and reveals that countries with stronger governance, higher human capital, and robust infrastructure tend to exhibit greater resilience, while fragile states and resource-dependent economies are more vulnerable. Notably, the DRI calculated using both dimension-specific and all-indicator PCA produces closely aligned values, indicating the choice of conducting PCA at the dimension level does not significantly alter the overall assessment of disaster resilience. These insights provide a foundation for targeted disaster risk reduction strategies and highlight areas where international cooperation and policy interventions can strengthen resilience in the region.Article Vim-Polyp: Multimodal Colon Polyp Dataset with Video, Histopathology, and Protein Expression(Nature Portfolio, 2025-12-03) Dogan, Refika Sultan; Akay, Ebru; Dogan, Serkan; Yilmaz, BulentThe dataset in this study includes 202 videos with a total of 422 minutes, reaching Kayseri City Hospital's gastroenterology department as colonoscopy videos and 1903 microscopy images between 2019 and 2021. It includes 399 colonoscopy, microscopy images, and pathological diagnoses of polyps, as well as immunohistochemical staining results for proteins that play an important role in the assessment of cancerous cells, such as staining results for p53 (clone: bp53-11), Ki-67 (clone: 30-9), CD34 (clone: QBend/10), PD-L1 (clone: SP142), BRAF (clone: V600E) and VEGF (clone: SP125). By sharing the data openly, we aim to facilitate benchmarking, exploratory analysis and transfer-learning studies on colorectal polyps and cancer. In combination with external datasets or pretrained models, the resource can help advance data-driven detection and characterisation work. The diverse range of polyps assigned to cancer stages from 201 patients makes this tool valuable for researchers and clinicians in furthering diagnosis and treatment.Article Citation - WoS: 11Citation - Scopus: 10UV Light Promoted Dihydrolipoic Acid and Its Alanine Derivative Directed Rapid Synthesis of Stable Gold Nanoparticles and Their Catalytic Activity(Nature Portfolio, 2024-10-21) Temur, Nimet; Dadi, Seyma; Nisari, Mustafa; Ucuncuoglu, Neslihan; Avan, Ilker; Ocsoy, IsmailIn general, colloidal gold nanoparticles (AuNPs) have been synthesized in heated or boiling water containing HAuCl4 precursor with sodium citrate as reducing stabilizing reagent. Although temperature plays a driving for synthesis of AuNPs, elevated temperature in thermal reduction method causes aggregation of the AuNPs. The preferential, rapid and strong binding of dihydro-lipoic acid and its derivatives on surface of AuNPs via thiol - Au chemistry promote the production of very stable AuNPs. In this study, we have developed citric acid (CA), dihydrolipoic acid (DHLA) and DHLA-Alanine (DHLA-Ala) directed rapid synthesis of ultra-stable AuNPs, DHLA@AuNPs and DHLA-Ala@AuNPs, under the UV (311 nm) irradiation at room temperature (RT: 25 degrees C) in around 10 min (min). CA is used as a potential reducing agent to expedite both reduction of Au3+ ion and AuNP formation, DHLA and DHLA-Ala act as stabilizing agents by replacing CA molecules on surface of AuNPs in order to produce quite stable AuNP. It is worthy to mention that reduction of Au3+ ion, formation and surface stabilization of AuNPs are consequently occurred in one step. We also investigated how experimental parameters including reaction time and temperature, pH of reaction solution, affect formation of the AuNPs. The effects of salt concentration and storage temperature were studied to show stability of the AuNPs. The synthesized DHLA@AuNPs and DHLA-Alanine@AuNPs were characterized via UV-Vis spectrophotometer (UV-Vis), scanning transmission electron microscope (STEM), dynamic light scattering (DLS) and Zeta potential (ZT) devices. The reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was efficiently catalyzed by the AuNPs in the presence of sodium borohydride in aqueous solution.Article Citation - WoS: 55Citation - Scopus: 53MoO3/WO3 as Electrode Material for Supercapacitor and Catalyst for Methanol and Ethanol Electrooxidation(Nature Portfolio, 2024-04-30) Askari, Mohammad Bagher; Salarizadeh, Parisa; Zadeh, Mohammad Hassan Ramezan; Ramezan zadeh, Mohammad HassanThe potential of metal oxides in electrochemical energy storage encouraged our research team to synthesize molybdenum oxide/tungsten oxide nanocomposites (MoO3/WO3) and their hybrid with reduced graphene oxide (rGO), in the form of MoO3/WO3/rGO as a substrate with relatively good electrical conductivity and suitable electrochemical active surface. In this context, we presented the electrochemical behavior of these nanocomposites as an electrode for supercapacitors and as a catalyst in the oxidation process of methanol/ethanol. Our engineered samples were characterized by X-ray diffraction pattern and scanning electron microscopy. As a result, MoO3/WO3 and MoO3/WO3/rGO indicated specific capacitances of 452 and 583 F/g and stability of 88.9% and 92.6% after 2000 consecutive GCD cycles, respectively. Also, MoO3/WO3 and MoO3/WO3/rGO nanocatalysts showed oxidation current densities of 117 and 170 mA/cm(2) at scan rate of 50 mV/s, and stability of 71 and 89%, respectively in chronoamperometry analysis, in the MOR process. Interestingly, in the ethanol oxidation process, corresponding oxidation current densities of 42 and 106 mA/cm(2) and stability values of 70 and 82% were achieved. MoO3/WO3 and MoO3/WO3/rGO can be attractive options paving the way for prospective alcohol-based fuel cells.Article Citation - WoS: 7Citation - Scopus: 9Green Synthesis of Silver Nanoparticles From Pomegranate Peel and Their Application in PVA-Based Nanofibers for Coating Minced Meat(Nature Portfolio, 2025-05-16) Gencag, Burcu Sari; Kahraman, Kevser; Ekici, Lutfiye; Sari Gencag, BurcuIn this study, silver nanoparticles (AgNPs) were synthesized via a green method from pomegranate peel extract and incorporated into polyvinyl alcohol (PVA) to produce AgPVA nanofibers through electrospinning. Nanofibers containing different silver concentrations (0.5, 1, and 1.5% Ag) were used as coating materials to coat minced meat, and their effects on various quality parameters during storage at 4 degrees C were evaluated. FTIR, XRD, SEM, and antibacterial analyses were conducted for the characterization of AgNPs and AgPVA nanofibers. To assess the quality characteristics of the minced meat during storage, pH, color, peroxide, TBARS, and microbiological analyses were performed. The results indicated that silver concentrations up to 1% could delay oxidation in minced meat and help preserve its quality. Compared with the other samples, the samples coated with 0.5% AgPVA (A1) and 1.0% AgPVA (A2) nanofibers exhibited a significant antimicrobial effect at the 6-day storage point (p < 0.05). The migration of AgNPs into minced meat was monitored during storage, and all migration values remained below the European food safety authority (EFSA) safety limit of 0.05 mg/kg, demonstrating the safety of the coatings. These findings suggest that AgPVA nanofibers synthesized via a green method could be a promising approach for extending the shelf life of perishable foods by reducing spoilage.Article Citation - WoS: 59Citation - Scopus: 54Atomically Precise Gold Nanoclusters at the Molecular-to Transition With Intrinsic Chirality From Surface Layers(Nature Portfolio, 2023-04-26) Liu, Li-Juan; Alkan, Fahri; Zhuang, Shengli; Liu, Dongyi; Nawaz, Tehseen; Guo, Jun; He, JianChiral metal nanoclusters prepared from achiral ligands generally contain chiral kernel structures. Here, the authors report an alternative type of gold nanoclusters whose intrinsic chirality arises solely from the arrangement of the organic components on their surface. The advances in determining the total structure of atomically precise metal nanoclusters have prompted extensive exploration into the origins of chirality in nanoscale systems. While chirality is generally transferrable from the surface layer to the metal-ligand interface and kernel, we present here an alternative type of gold nanoclusters (138 gold core atoms with 48 2,4-dimethylbenzenethiolate surface ligands) whose inner structures are not asymmetrically induced by chiral patterns of the outermost aromatic substituents. This phenomenon can be explained by the highly dynamic behaviors of aromatic rings in the thiolates assembled via pi - pi stacking and C - H center dot center dot center dot pi interactions. In addition to being a thiolate-protected nanocluster with uncoordinated surface gold atoms, the reported Au-138 motif expands the size range of gold nanoclusters having both molecular and metallic properties. Our current work introduces an important class of nanoclusters with intrinsic chirality from surface layers rather than inner structures and will aid in elucidating the transition of gold nanoclusters from their molecular to metallic states.Article Citation - WoS: 5Citation - Scopus: 3Arousal State Transitions Occlude Sensory-Evoked Neurovascular Coupling in Neonatal Mice(Nature Portfolio, 2023-07-17) Gheres, Kyle W. W.; Unsal, Hayreddin S. S.; Han, Xu; Zhang, Qingguang; Turner, Kevin L. L.; Zhang, Nanyin; Drew, Patrick J. J.In the adult sensory cortex, increases in neural activity elicited by sensory stimulation usually drive vasodilation mediated by neurovascular coupling. However, whether neurovascular coupling is the same in neonatal animals as adults is controversial, as both canonical and inverted responses have been observed. We investigated the nature of neurovascular coupling in unanesthetized neonatal mice using optical imaging, electrophysiology, and BOLD fMRI. We find in neonatal (postnatal day 15, P15) mice, sensory stimulation induces a small increase in blood volume/BOLD signal, often followed by a large decrease in blood volume. An examination of arousal state of the mice revealed that neonatal mice were asleep a substantial fraction of the time, and that stimulation caused the animal to awaken. As cortical blood volume is much higher during REM and NREM sleep than the awake state, awakening occludes any sensory-evoked neurovascular coupling. When neonatal mice are stimulated during an awake period, they showed relatively normal (but slowed) neurovascular coupling, showing that that the typically observed constriction is due to arousal state changes. These result show that sleep-related vascular changes dominate over any sensory-evoked changes, and hemodynamic measures need to be considered in the context of arousal state changes. A combination of optical imaging, electrophysiology, and BOLD fMRI in unanesthetized neonatal mice reveals that sleep-related vascular changes dominate over sensory-evoked changes.Article Citation - WoS: 7Citation - Scopus: 7A Genome-Scale Metabolic Model of Parasitic Whipworm(Nature Portfolio, 2023-10-31) Bay, Omer F.; Hayes, Kelly S.; Schwartz, Jean-Marc; Grencis, Richard K.; Roberts, Ian S.Genome-scale metabolic models are widely used to enhance our understanding of metabolic features of organisms, host-pathogen interactions and to identify therapeutics for diseases. Here we present iTMU798, the genome-scale metabolic model of the mouse whipworm Trichuris muris. The model demonstrates the metabolic features of T. muris and allows the prediction of metabolic steps essential for its survival. Specifically, that Thioredoxin Reductase (TrxR) enzyme is essential, a prediction we validate in vitro with the drug auranofin. Furthermore, our observation that the T. muris genome lacks gsr-1 encoding Glutathione Reductase (GR) but has GR activity that can be inhibited by auranofin indicates a mechanism for the reduction of glutathione by the TrxR enzyme in T. muris. In addition, iTMU798 predicts seven essential amino acids that cannot be synthesised by T. muris, a prediction we validate for the amino acid tryptophan. Overall, iTMU798 is as a powerful tool to study not only the T. muris metabolism but also other Trichuris spp. in understanding host parasite interactions and the rationale design of new intervention strategies. In this work, Bay et al describe the construction of the first genome-scale metabolic model for the parasitic whipworm, Trichuris muris and use it to identify novel metabolic pathways and predict critical enzymes and essential metabolites for worm survival.