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Holmium-Molybdate Nanoparticle-Modified Carbon Paste Electrode for Electrocatalytic Detection of Paracetamol
No full textHolmium tetra-molybdate nanoparticles have been employed for the first time to modify carbon paste electrodes, leading to the creation of an electrochemical sensor for the detection of paracetamol (PAR). These nanoparticles were synthesized using a straightforward, one-pot, organic-solvent-free hydrothermal method. FTIR, XPS, SEM/EDS, TEM, XRD patterns, and Raman spectra showed high crystallinity of the material, characteristic stretching vibrations with an empty part of the spectrum in the range of 750–450 cm–1, confirming the regular form of tetramolybdate, with a uniform distribution of components. The resulting material demonstrated very good electrocatalytic performance, with a 4.5 times decrease in the Rct value obtained in the EIS study, significant current promotion, and a decrease in the ΔE value resulting from CV measurements, which can be attributed to its unique size and morphology. The practical feasibility of nanomaterials in analytical applications was demonstrated through the development of an electrochemical sensor that was then used to establish a sensor platform for PAR detection. Under optimized square wave voltammetry (SWV) conditions, the sensor exhibited a wide linear range of 3–300 μM, a low limit of detection of 0.314 μM, and a sensitivity of 0.239 μA μM–1 cm–2. These findings, along with satisfactory sensitivity, stability, and repeatability, underscore the potential of this sensor for routine paracetamol analysis, shown through the determination of PAR in pharmaceutical samples with 99.72% to 101.92% recovery values. Effective practical application in real matrices highlights this material as a high-performance structure for the real-time monitoring of biologically active compounds and applications in medicinal analytical chemistry and the pharmaceutical industry
A Review on Ionic Liquids in the Design of Carbon-Based Materials for Environmental Contaminant Removal
No full textContamination of water and soil with a wide range of pollutants, including pesticides, pharmaceuticals, and industrial chemicals, remains a significant environmental challenge. Carbon-based materials are widely recognized for their high adsorption capacity, chemical stability, and the possibility to tailor their surface and structural properties. In recent years, ionic liquids (ILs) have been explored as useful media and functionalization agents in the preparation of such materials. Their unique physicochemical properties can facilitate activation, influence pore structure, and introduce specific functional groups that improve interactions with target contaminants. This review summarizes recent developments in the use of ILs for the synthesis, modification, and regeneration of carbonaceous adsorbents. Particular attention is given to IL-assisted activation techniques, surface functionalization strategies, and reported improvements in adsorption performance. Key challenges, such as the environmental impact and cost of ILs, as well as prospects for developing more sustainable IL-based processes, are also discussed. Taken together, these findings highlight the relevance of IL-enabled carbon materials for practical adsorption processes, including water and wastewater treatment, selective pollutant removal, and regeneration-driven purification systems
Assessing performance of atenolol removal from contaminated water using zero-valent iron impregnated apricot stone biochar
No full textThis study investigates the performance of zero-valent iron (ZVI) impregnated apricot stone-derived biochar (ZVI/ASB) for the removal of atenolol (ATL), a widely detected pharmaceutical pollutant, from contaminated water. The biochar was synthesized at pyrolysis temperatures of 800, 900, and 1000 °C, with ZVI/ASB-800 exhibiting the highest sorption capacity due to its superior textural properties, including a Brunauer-Emmett-Teller (BET) surface area of 1162 m2/g and a well-developed porous structure. Characterization techniques such as X-Ray diffraction (XRD) analysis, Fourier Transform Infrared Spectroscopy (FTIR), and Scanning electron microscopy (SEM) confirmed the successful incorporation of ZVI and the material's enhanced physicochemical properties. Batch sorption experiments evaluated the effects of pH, sorbent dosage, stirring speed, and initial ATL concentration, with optimal conditions identified at pH 9, a dosage of 0.75 g/L, and a stirring speed of 250 rpm. The sorption process followed the Langmuir isotherm model and pseudo-second-order kinetics. The maximum experimental sorption capacity reached 129 mg/g, demonstrating competitive performance compared to commercial sorbents. Reusability tests showed a retention of 73.2 % removal efficiency after five cycles, highlighting the material's considerable stability. These findings underscore the potential of ZVI/ASB-800 as a cost-effective and sustainable sorbent for pharmaceutical pollutant removal, leveraging agricultural waste for environmental remediation
Quantum Computing of Many-body Effects in Quantum Dots
No full textQuantum mechanics is witnessing its second revolution. It is of fundamental
academic interest and of paramount benefit for new and nascent industries and technologies.
The QM is the driving force behind the discovery practical applications, such as quantum
camera, quantum time, quantum computing or quantum cryptography, to name a few.
Consumer electronics nowadays, like mobile phones, the Internet, GPS, or QLED TV, would
be impossible without the progress in QM. The field of QM was established by Max Planck in
1900. From then on, tremendous effort has been dedicated to the study of QM, which led to the
ground-breaking invention of the laser, the creation of entangled quantum particles,
semiconductor quantum dots (QD), the cooling of atoms, quantum manipulation of individual
atoms, and quantum computing (QC). The discovery of those phenomena was awarded by
several Nobel Prizes, most notably in 2022 to Aspect, Clauser & Zeilinger for the discovery of
entanglement and in 2023 to Ekimov, Brus and Bawendi for the discovery of QD. With a new
paradigm and extremely efficient approaches to solving problems that were, until recently, in
the realm of science fiction only. Quantum computation is the most anticipated new technology
on the horizon. QC aims to solve challenging computational tasks by utilising rules of quantum
mechanics to manipulate the information. Here, we propose to simulate quantum systems
consisting of many thousands of atoms in QD and its many body phenomena on a quantum
computer based on the arrays of Rydberg atoms. The precision and robustness offered by the
Ry-mediated entanglement protocols are the key factors for their penetration and wider
applicability in experiments and in nascent quantum industries. However, to realise them, one
needs to control a large assembly of quantum objects with exquisite precision. This is a
tremendously difficult task, both from the point of intellectual comprehension and from the
technological point of view. Indeed, such academic developments spur the race in quantum
technology, ultimately aiming at quantum supremacy, when the quantum computers will
outperform the speed and abilities of conventional supercomputers when manipulating data.
Along the overview of the historical context, I will review the program of my Fulbright
Scholarship which is devoted to quantum computing with Rydberg atoms. I will offer the
contribution to the current understanding and challenges of many-body processes in QD and
how they can be addresses by Ry-atoms quantum computers.19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026
Scalability of splitters based on waveguide arrays
No full textPhotonic integrated circuits (PICs) are a promising route towards the next generation of classical and quantum information technologies [1, 2]. An important challenge before their widespread implementation is scaling to a competitive footprint and high data transfer rate [3]. This translates into solving the problems of crosstalk between photonic components and energy loss, both exacerbated by minimization. Here, we present the design of a miniature 1:N splitter based on linearly coupled waveguide arrays in silicon on insulator (SOI). Previously, we demonstrated the proof of principle in waveguides realized by femtosecond laser writing in glass [4]. The main difference between these two platforms is the contrast in refractive indices of the waveguide core and cladding. SOI has 2 orders of magnitude higher contrast, which allows for sub-micron interwaveguide spacing while maintaining coupling only between nearest neighbours and single-mode guiding. Our finite-difference-time-domain simulations in Lumerical show promising prospects for realizing small-footprint low-loss splitters. A few-micrometer splitter width requires waveguide fan-out to tens of micrometers needed for coupling to external sources and detectors and, hence, the multiscale simulation. We will discuss these challenges and solutions and offer insights into the mask design as the final step before fabrication. Further developments include incorporating non-nearest-neighbour coupling to achieve the ultimate footprint scaling for single-mode waveguides.19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026
Wavelength Demultiplexers Based on Self-Imaging in Optical Lattices with Length-Modulated Waveguides
No full textWe have proposed a wavelength demultiplexer based on wavelength-dependent self-imaging in linearly coupled optical lattices, implemented using a simple and compact photonic lattice configuration [1]. Straight waveguides ensure low propagation losses, while intuitive control of the coupling parameters allows precise tuning of both the output wavelength and the operational bandwidth. An experimental proof of concept is provided through fabrication of the demultiplexers in borosilicate glass using femtosecond laser writing techniques [2, 3]. The wavelength separation is achieved via self-imaging and perfect state transfer of the input optical field during propagation through a lattice with length-modulated waveguides. Specifically, longer wavelengths revive in the input waveguide, whereas shorter wavelengths are fully transferred to the opposite output port. However, this approach allows for dichroic separation only. To extend the splitting capability to multiple wavelengths, we introduce a modified structure with waveguide lengths as additional parameters. Only the input waveguide and its nearest neighbor are of equal lengths, while successive waveguides are gradually shortened. We will present the design principle, numerical simulations and performance evaluation of 3- and 4- wavelength demultiplexers.19th Photonics Workshop, (International Conference), Kopaonik, March 08-12, 2026
Tailoring cobalt nanostructures via e-beam glancing angle deposition method: Thickness-dependent effects on optical and photocatalytic properties
No full textCobalt (Co) thin films were deposited onto silicon substrates to the thicknesses of 50 nm, 160 nm, 240 nm, and 360 nm in order to analyze the changes in optical and photocatalytic properties. The morphology of the films was characterized by an increase in column diameter and porosity with increasing film thickness. X-ray diffraction and transmission electron microscopy analyses demonstrated that the deposited samples exhibit a fine-grained structure. The chemical analysis revealed that metallic Co is the predominant phase in the deposited films, with a certain amount of the oxide phase. Optical properties, including the refractive index and extinction coefficient, exhibit variations with thickness, which can be attributed to the changes in the microstructure and porosity. Additionally, the electrical resistivity was found to decrease with thickness, suggesting relationship between film structure and conductivity. Both, optical and electrical properties were influenced by the growth mechanism, with behavior strongly linked to defect concentration and the metallic nature of the Co thin films. Finally, the photocatalytic activity of the cobalt nanostructures demonstrated their capability to degrade methylene blue organic dye under light irradiation, highlighting the potential of Co nanomaterials for environmental remediation applications
Mapping the heart rhythm: Leveraging Poincaré plot asymmetry to detect congestive heart failure and age-related changes
No full textObjectives We propose an improvement to our novel approach for Heart Rate Asymmetry (HRA) assessment based on Poincaré Plots (PPs) derived from Heart Rate Variability (HRV). We evaluate the ability of the modified Asymmetry Magnitude Index (AMI) to discriminate between clinically distinct cohorts and its applicability to short-term HRV. Methods For both AMI variants, the degree of asymmetry is quantified by applying the Frobenius norm to the Asymmetric Matrix Component (AMC) of an estimated two-dimensional PP distribution. The approaches differ only in the estimation method, with the modified AMI using Kernel Density Estimation (KDE) method instead of square histograms. The KDE AMI is compared with the Histogram-based counterpart (HB AMI), standardized PP descriptors, and established HRA measures using 20-minute HRV from healthy subjects (HS) and patients with Congestive Heart Failure (CHF), as well as segments of 1, 5, and 10 min. Results The KDE AMI and standardized PP descriptor SD1 outperform other measures, distinguishing older HS vs. patients with CHF (oHS vs. CHF) and younger vs. older healthy subgroups (yHS vs. oHS), irrespective of HRV duration. In contrast, the HB AMI and SD2 perform well only at longer timescales for oHS vs. CHF, while offering similar discrimination for yHS vs. oHS. Other HRA indices reach statistical significance only at specific timescales. Conclusions KDE AMI successfully detects differences in HRA between clinically distinct cohorts. The discriminative power of KDE AMI is comparable to that of SD1, whereas among HRA measures, it demonstrates the strongest and most consistent performance across short-term timescales. Moreover, the results justify the rationale for the employment of KDE to address the limitations of the Histogram-based counterpart. Further refinement and validation of the proposed index could pave the way for its seamless integration into routine clinical practice and wearable technologies. To strengthen its applicability, current limitations should be addressed by evaluating the index across a more diverse patient sample
From noble metal ion implantation to tailored optical and electrical performance of TiN thin films via rapid thermal annealing
No full textTitanium nitride (TiN) thin films were implanted with 110 keV silver ions and 150 keV gold ions at a fluence of 5 × 1016 ions/cm2 and subsequently subjected to rapid thermal annealing at 700◦C for 10 s, 30 s, and 60 s. Spectroscopic ellipsometry, four-point probe measurements, and X-ray photoelectron spectroscopy were used to monitor changes in dielectric function, electrical conductivity, and surface chemistry. Silver implantation induced moderate lattice damage and nanoparticle formation, partially reducing metallicity and optical absorption, which were efficiently restored by short-term annealing via defect healing and improved carrier mobility. Gold implantation caused stronger structural disorder, suppressing metallic and optical response, with only limited recovery after annealing. Drude–Lorentz analysis quantitatively correlated plasma frequency and damping constant with resistivity trends, demonstrating a direct link between defect dynamics and macroscopic optical and electrical properties. X-ray photoelectron spectroscopy confirmed these changes occurred independently of surface oxidation, indicating that defect evolution and free-carrier modulation are the primary drivers. These results provide a controllable strategy to tune TiN thin films through ion implantation and thermal treatment, offering guidance for designing plasmonic and optoelectronic coatings
Low-carbon Materials for Environmental Monitoring
No full textIn response to the escalating challenges posed by climate change and environmental degradation, there is a growing imperative to reduce the carbon footprint associated with monitoring technologies. The use of low-carbon materials in environmental monitoring is crucial, as it minimizes the environmental impact of these technologies and aligns with global sustainability goals. This chapter reviews various carbon-based, low-carbon materials that exhibit remarkable potential for applications in environmental sensors, detectors, and monitoring devices. It explores the synthesis and fabrication methods of these materials, outlining their unique properties that contribute to enhanced sensor performance. A significant portion of the chapter is dedicated to the diverse applications of low-carbon materials in environmental monitoring. The advantages of employing these materials, such as improved sensitivity, selectivity, and durability, are discussed in detail. Furthermore, the chapter addresses the challenges and future prospects associated with the integration of low-carbon materials into environmental monitoring systems. It explores potential hurdles in large-scale production, standardization, and technological scalability while also envisioning the role of emerging technologies and interdisciplinary collaborations in advancing the field. By highlighting the innovative solutions and encouraging a shift toward eco-conscious practices, this chapter aims to contribute to the ongoing efforts to build a more sustainable and resilient future