IYTE GCRIS Database (Izmir Institute of Technology)
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An Analytical Methodology for the Determination of Cadmium Bound To Whey-Proteins by Laser-Induced Breakdown Spectroscopy at Low Pressures
No full textIn this study, a dried-droplet LIBS methodology for determining cadmium in cow milk has been developed. The performance of the methodology was shown by standard and real protein samples. A standard protein, bovine serum albumin (BSA), and whey protein extracted from skim cow milk were incubated in standard Cd solutions, and the complex solution was filtered through cut-off filters by centrifugation. The unreacted cadmium in the filtrate and Cd-bound protein in the filtered fraction were loaded separately onto a Si-wafer substrate and analyzed via dried-droplet LIBS methodology. Measurements were performed at reduced pressures by taking advantage of the signal enhancement effect. The optimum pressure for most Cd emission lines was found to be 100 mbar. It has been shown that the dried-droplet LIBS methodology at reduced pressures can be used for the identification and determination of free and protein-bound Cd in the whey matrix. The concentration-based detection limit of Cd bound to whey proteins was determined to be 20.2 ng mL- 1, which corresponds to as low as 10 pg in absolute amount with a sample volume of 500 nL. The LOQ value is estimated as 67.3 ng mL- 1 and 33.3 pg, in terms of concentration unit and absolute amount, respectively. The use of small sample volumes is important in the analysis of limited amounts of samples, such as body fluids. Preconcentration studies with multiple loadings of the sample on the same spot resulted in improvements in concentration-based detection. 8 ng mL- 1 Cd in the whey matrix that could not be determined by a single droplet loading due to being below the detection limit; could be determined after 10 consecutive loadings. The methodology may also be applied to the determination of other toxic metals bound to proteins for food quality control
Optimized Lithium(I) Recovery From Geothermal Brine of Germencik, Türkiye, Utilizing an Aminomethyl Phosphonic Acid Chelating Resin
No full textThis study investigates the performance of Lewatit TP 260 ion exchange resin for the efficient recovery of lithium (Li(I)) from geothermal water sourced from the Germencik Geothermal Power Plant in Türkiye. A series of batch sorption experiments were performed to evaluate the influence of key parameters, including resin dosage, solution pH, temperature, initial Li(I) concentration, and contact time, on the Li(I) recovery process. The optimal conditions were determined to be a resin dose of 0.5 g per 25 mL of geothermal water, pH in the range of 6–8, and a temperature of 25°C. Under these conditions, the resin achieved a maximum Li(I) recovery rate of 71% from the geothermal water. Sorption isotherms were further analyzed using the Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) models. Among these, the Langmuir model provided the best fit (R² = 0.9841), suggesting a maximum sorption capacity (qm) of 4.31 mg/g. Continuous recovery experiments conducted in column mode confirmed the practical applicability of Lewatit TP 260, achieving a total sorption capacity of 0.41 mg Li(I)/mL resin. The findings exhibit the potential of this resin as a viable sorbent for sustainable Li(I) extraction from geothermal brines, supporting the development of green energy technologies and contributing to the circular economy. © 2024 Taylor ; Francis Group, LLC
Gate-Controlled Photoresponse in an Individual Single-Walled Carbon Nanotube Modified With a Fluorescent Protein
No full textBionanohybrids of carbon nanotubes and fluorescent proteins (FPs) are a promising class of materials for optoelectronic applications. Understanding and controlling the charge transport mechanism between FPs and carbon nanotubes are critical to achieving functional reproducibility and exploring novel synergetic effects. This work demonstrates a novel phenomenon of photocurrent generation in field-effect transistors based on the conjugation of an individual single-walled carbon nanotube (SWCNT) and FPs. When studying the effect of gate voltage on the photoresponse, reversible switching from fast positive to a slow negative photoresponse in bionanohybrids associated with depletion and accumulation modes, respectively is observed. The latter demonstrates a stable memory effect after the light is turned off. It is revealed that in depletion mode, the charge carriers from the protein are not trapped at the interface due to effective screening by the gate potential. It is suggested that the main mechanism in photoresponse switching is a competitive effect between photogating and effective photodoping of the SWCNT by charges trapped at the nanotube interface. The noticeable effect of water molecules can support proton transfer as the main mechanism of charge transfer. This result illustrates that SWCNT/FP bionanohybrids bear great potential for the realization of novel optoelectronic devices. © 2024 The Author(s). Advanced Electronic Materials published by Wiley-VCH GmbH
Development of a Dopamine-Based Surface Modification Technique To Enhance Protein Fouling Resistance in Commercial Ultrafiltration Membranes
No full textThis study introduces a new method for modifying ultrafiltration membranes using dopamine polymerization to overcome issues such as prolonged polymerization times, potential pore narrowing, and insufficient formation of hydrophilic groups. The technique involves continuously supplying oxygen (O2) gas from the porous backside of the membrane while simultaneously applying an aqueous dopamine solution to the active top surface. TGA and XPS analyses revealed that 10 kDa commercial polysulfone (PSF) membranes coated with O2 backflow contained more dopamine than those modified using the classical method. Additionally, changes in contact angle and zeta potential values were more pronounced with the O2 backflow method. Dopamine coating for 10 and 20 min improved the pure water permeance of the PSF membrane, whereas a 40-min coating decreased it. Notably, the reduction in permeance was 2.5 times less with the O2 backflow method than with the classical method. The classical dopamine coating method did not enhance the PSF membrane's resistance to fouling during whey filtration; in fact, 20 and 40-min coatings caused more significant flux declines compared to the unmodified membrane. Conversely, 10 and 20 min of PDA coating under O2 backflow improved fouling resistance, though this benefit disappeared with a 40-min coating
Effect of the Synthesis Method and Particle Size on Bczt Electrocaloric Properties
No full textIn this study, the electrocaloric properties of BCZT ceramics fabricated through different processing methods: solid-state and sol-gel were investigated. The calcination process was done for BCZT powders obtained by sol-gel process at 900 degrees C for 2 h and by solid-state calcination method at 1200 degrees C for 6 h. BCZT-SG ceramics exhibited higher Delta T values, particularly at lower temperatures (similar to 0 degrees C-20 degrees C), and a stronger response to the electric field, suggesting a more efficient domain structure due to sol-gel processing. Notably, BCZT-SGH samples demonstrated the most complex and pronounced electrocaloric behavior, with dual Delta T peaks around 0 degrees C and 50 degrees C, and the highest Delta T of 2.5 K at 80 kV/cm and 50 degrees C, surpassing values in the literature. Especially, high Delta T results at 0 degrees C allows using this material in the extreme conditions. These results emphasize the significant role of processing techniques in tailoring the structural, dielectric, and electrocaloric properties of BCZT ceramics for high-performance energy applications
A Finite Difference Approach To Solve the Nonlinear Model of Electro-Osmotic Flow in Nano-Channels
No full textThis article considers a system of coupled equations constructed by the nonlinear model of electro-osmotic flow through a one-dimensional nano-channel. Functions that belong to this system include distributions of mole fraction of cation and anion, electrical potential, and velocity. We try to find an accurate closed-form solution. To this end, some mathematical approaches are concurrently used to convert the equations to a nonlinear differential equation in terms of the mole fraction of anion. The latter nonlinear differential equation is transformed into a nonlinear algebraic system by the finite difference method, and the system's solution is obtained using Newton's iterative algorithm. Furthermore, equations for the mole fraction of cation, electrical potential, and velocity in terms of the mole fraction of anion are obtained. We calculate errors by substituting the proposed solution into the equations to validate the results. Comparing the results with some other numerical research works demonstrates an acceptable accuracy
Fbg-Based Temperature and Fire Sensors for Use in Industrial Microwave Ovens
No full textIndustrial microwave-heating systems play a crucial role in sectors such as food processing and materials manufacturing, where precise temperature control and safety are paramount. However, traditional systems often face challenges like uneven heat distribution and elevated fire risks due to the inherent characteristics of microwave heating. This study introduces a fiber-optic sensor-based monitoring system designed to address these critical issues. The system features an advanced fiber-optic sensor capable of 2D temperature distribution monitoring and a specialized fire detection mechanism, both aimed at significantly reducing risks and improving the heating process. Experimental results demonstrate the potential for transformative advancements in industrial heating technologies, paving the way for enhanced process efficiency and safety. © 2025 SPIE
Magnetically Controllable and Degradable Milliscale Swimmers as Intraocular Drug Implants
No full textIntraocular drug implants are increasingly used for retinal treatments, such as age-related macular degeneration and diabetic macular edema, due to the rapidly aging global population. Although these therapies show promise in arresting disease progression and improving vision, intraocular implant-based therapies can cause unexpected complications that require further surgery due to implant dislocation or uncontrolled drug release. These frequent complications of intraocular drug implants can be overcome using magnetically controllable degradable milliscale swimmers (MDMS) with a double-helix body morphology. A biodegradable hydrogel, polyethylene glycol diacrylate, is employed as the primary 3D printing material of MDMS, and it is magnetized by decorating it with biocompatible polydopamine-encapsulated iron-platinum nanoparticles. MDMS have comparable dimensions to commercial intraocular implants that achieve translational motions in both aqueous and vitreous bodies. They can be imaged in real-time using optical coherence tomography, ultrasound, and photoacoustic imaging. Thanks to their biodegradable hydrogel-based structure, they can be loaded with anti-inflammatory drug molecules and release the medications without disrupting retinal epithelial viability and barrier function, and decrease proinflammatory cytokine release significantly. These magnetically controllable swimmers, which degrade in a couple of months, can be used for less invasive and more precise intraocular drug delivery compared to commercial intraocular drug implants. © 2025 The Author(s). Advanced Science published by Wiley-VCH GmbH
Fluorescent Protein With Environmentally-Sensitive Fluorescence Lifetime for Quantitative Ph Measurement
No full textIntracellular pH is a key factor in cell homeostasis, regulated within specific compartments, and changes in pH can result from or affect biochemical pathways. This study explores a yellow fluorescent protein EYFP-G65T as a core for a time-resolved pH-indicator. Among the tested designs-a circular permutant, a chimeric SypHer3s-like construct, and an unmodified protein-the unmodified EYFP-G65T performed best for live-cell imaging. Upon two-photon excitation, purified EYFP-G65T exhibited a 4.5-fold increase in mean fluorescence lifetime across pH 5.5-7 and a 7-fold change in its major component's lifetime from pH 6.5-8. Using this indicator, we measured pH values ranging from 6 to 8 in various organelles, and mapped pH shifts in mitochondria and the Golgi apparatus in response to stimuli
Impact of Green Wall and Roof Applications on Energy Consumption and Thermal Comfort for Climate Resilient Buildings
No full textNowadays, reducing energy consumption and obtaining thermal comfort are significant for making educational buildings more climate resilient, more sustainable, and more comfortable. To achieve these goals, a sustainable passive method is that of applying green walls and roofs that provide extra thermal insulation, evaporative cooling, a shadowing effect, and the blockage of wind on buildings. Therefore, the objective of this study is to evaluate the impact of green wall and roof applications on energy consumption and thermal comfort in an educational building. For this purpose, a university building in the Csb climate zone is selected and monitored during one year, as a case study. Then, the case building is modelled in a well-calibrated dynamic building energy simulation tool and twenty-one different plant species, which are mostly used for green walls and roofs, are applied to the envelope of the building in order to determine a reduction in energy consumption and an increase in thermal comfort. The Hedera canariensis gomera (an ivy species) plant is used for green walls due to its aesthetic appeal, versatility, and functional benefits while twenty-one different plants including Ophiopogon japonicus (Mando-Grass), Phyllanthus bourgeoisii (Waterfall Plant), and Phoenix roebelenii (Phoenix Palm) are simulated for the green roof applications. The results show that deploying Hedera canariensis gomera to the walls and Phyllanthus bourgeoisii to the roof could simultaneously reduce the energy consumption by 9.31% and increase thermal comfort by 23.55% in the case building. The authors acknowledge that this study is solely based on simulations due to the high cost of all scenarios, and there are inherent differences between simulated and real-world conditions. Therefore, the future work will be analysing scenarios in real life. Considering the limited studies on the effect of different plant species on energy performance and comfort, this study also contributes to sustainable building design strategies