Magnetic sensors based on the colossal magnetoresistance (CMR) effect in manganite thin films are promising for high-field measurements due to their wide operating range, low magnetoresistance anisotropy, and ability to function without full saturation at extremely high magnetic fields. However, the long-term stability of their transport properties remains a key challenge for practical sensor applications. In this work, accelerated aging of nanostructured La1−xSrxMnyO3 thin films was investigated for two manganese compositions: nominally stoichiometric (y = 1.05) and Mn-excess (y = 1.15). The electrical resistivity and magnetoresistive properties strongly depended on the manganese content and substrate type. Accelerated aging was induced by annealing at 100 °C in an argon atmosphere, and the evolution of the transport properties was analyzed using a stretched-exponential relaxation model. The analysis of the extracted parameters indicated defect-related mechanisms governing transport stability. It was found that despite the increase in resistivity during thermal treatment, the magnetoresistance changes were insignificant. The results provide insights into the aging behavior of nonstoichiometric manganite films and offer guidance for optimizing stabilization procedures in CMR-based magnetic field sensors.

The presence of microplastics in agrosystems has become a growing environmental concern. In particular, LDPE plastic mulching has been recognized as one of the primary pathways by which microplastics are introduced into terrestrial environments and eventually transported across multiple ecosystems. Recent efforts to reduce microplastics have focused on advanced oxidation processes, such as photocatalytic degradation. However, it remains uncertain how the physical properties of microplastics influence the photocatalytic degradation performance. This study investigates the photocatalytic degradation of LDPE films in two colors (black and transparent) and two sizes (1 & times;1 mm and 3 & times;3 mm) in the presence of Ag-TiO2 nanomaterials. Among the studied samples, black-colored LDPE films exhibited twice the mass loss compared to transparent LDPE films over 960 min. Furthermore, the mass loss increased as the LDPE film size decreased. Alterations in surface morphology and chemical structure were monitored before and after degradation. SEM imaging indicated a more pronounced formation of cracks, cavities, and pits in black-colored films compared to transparent ones. Meanwhile, FTIR analysis showed the formation of new absorption bands corresponding to oxygen-containing groups and unsaturated carbon bonds, with CI and VI values ranging from 0.43 to 0.93 and from 0.25 to 0.49, respectively. The results of the quenching test for ROS indicated that center dot OH was the primary radical that initiated and controlled the degradation process. This study advances current understanding of the role of physical properties of LDPE in photocatalytic processes by proposing a new mechanistic interpretation of LDPE film degradation in an Ag-TiO2-based system.

An in situ transmission electron microscopy study of Bi quantum dot (QD) formation in an annealed GaAsBi/AlAs multiple quantum well (MQW) structure is presented in this work. The investigated structure, containing two GaAsBi QWs and embedded in an AlGaAs parabolic quantum barrier (PQB), was grown on semi-insulating GaAs (100) and was transferred onto an in situ heating holder (DENS solutions) and heated up to 650 °C. Sample evolution was continuously recorded in situ in bright-field STEM mode. The analysis revealed that QD formation occurs at lower annealing temperatures in case of in situ heating of lamella than in bulk. In addition, we find that the mechanism governing Bi QD formation is different in the in situ TEM experiment compared to bulk ex-situ annealing. Comparison of the ex-situ and in situ annealed structures, as well as in-depth postannealed structure TEM analysis, is presented.

This work is focused to investigation of bismuth quantum dots formation mechanism using segregation process via two types of annealing of gallium arsenide bismide quantum well structures with aluminium gallium arsenide parabolic barriers: in-situ annealing in a molecular beam epitaxy reactor immediately after growth and ex-situ in a rapid thermal annealing oven. Both processes were performed in the range of temperatures of 600-750 degrees C and adjusting annealing time from 0 to 180 s. The structures were characterized using high resolution transmission electron microscopy, temperature and time dependent photoluminescence measurements, cathodoluminescence, Raman spectroscopy, and dimensional analysis. Transmission electron microscopy images demonstrated that in-situ annealing in a reactor at temperatures up to 750 degrees C for 0-150 s results in the formation of randomly oriented Bi quantum dots with a dominant size of about 10-15 nm, exhibiting cathodoluminescence at 0.9 eV at 10 K. The investigation using ex-situ rapid thermal annealing showed a trend that with increase of annealing temperature the intensity of quantum well related emission reduces, peak is redshifted and broadens, while the quantum dot related emission increases in intensity, suggesting the diffusion of bismuth atoms from the bismide lattice leading to formation of pure bismuth quantum dots.

In this work, we present a novel hybrid magnetic sensor that combines the unique properties of manganite and graphene to measure both the magnitude and direction of a magnetic field. The sensor consists of a nanostructured manganite film to detect the magnetic field strength and a graphene layer to determine the angle between the magnetic field and the sensor plane. This dual sensor approach increases sensitivity over a wide range of magnetic field strengths and provides directional information, making it ideal for applications such as object positioning and navigation. The sensor design, based on a voltage divider configuration, has been optimized to achieve high sensitivity. Experimental results in pulsed magnetic fields up to 21 T demonstrated the increased sensitivity offered by the graphene-manganite combination. In addition, a measurement system for recording and processing data was developed that enables real-time measurement of the magnetic field magnitude and its orientation.

This study presents a system for precisely measuring pulsed magnetic fields with high amplitude and microsecond duration with minimal interference. The system comprises a probe with an advanced magnetic field sensor and a measurement unit for signal conversion, analysis, and digitization. The sensor uses a thin nanostructured manganite La-Sr-Mn-O film exhibiting colossal magnetoresistance, which enables precise magnetic field measurement independent of its orientation. Films with different compositions were optimized and tested in pulsed magnetic fields. The measurement unit includes a pulsed voltage generator, an ADC, a microcontroller, and an amplifier unit. Two versions of the measurement unit were developed: one with a separate amplifier unit configured for the sensor positioned more than 1 m away from the measurement unit, and the other with an integrated amplifier for the sensor positioned at a distance of less than 0.5 m. A bipolar pulsed voltage supplying the sensor minimized the parasitic effects of the electromotive force induced in the probe circuit. The data were transmitted via a fiber optic cable to a PC equipped with a special software for processing and recording. Tests with 20–30 μs pulses up to 15 T confirmed the effectiveness of the system for measuring high pulsed magnetic fields.

This work is focused to the investigation of LED containing GaAsBi quantum dots embedded in a layer or parabolic quantum well formed in-situ in MBE reactor using segregation process as an alternative method.

In this work, we compare two molecular beam epitaxy (MBE) modes used for the growth of GaAsBi/GaAs multiple quantum well (MQW) structures. In the conventional growth mode, both the GaAsBi quantum well and GaAs barrier layers were grown at 370 degrees C, whereas in the modified growth mode, the substrate temperature was increased to 450 degrees C during GaAs barrier layer deposition. The results indicate that the elevated barrier growth temperature led to higher Bi incorporation and more homogeneous Bi distribution within GaAsBi, along with a reduction in defect density. On the other hand, MQW structures grown at a constant 370 degrees C temperature exhibited more uniform quantum well thickness. Despite its lower emission efficiency, the photoluminescence (PL) intensity was higher for the GaAsBi/GaAs MQW, where the entire structure was grown at the same 370 degrees C temperature, likely due to enhanced carrier localization.

Noble metal nanoparticles, specifically gold and silver, are extensively utilized in sensors, catalysts, surface-enhanced Raman scattering (SERS), and optical-electronic components due to their unique localized surface plasmon resonance (LSPR) properties. The production of these nanoparticles involves various methods, but among the environmentally friendly approaches, laser ablation stands out as it eliminates the need for toxic chemicals during purification. However, nanoparticle aggregation poses a challenge in laser ablation, necessitating the addition of extra materials that contaminate the otherwise clean process. In this study, we investigate the effectiveness of a biocompatible material, potassium chloride (KCl), in preventing particle aggregation. Although salt is known to trigger aggregation, we observed that certain concentrations of KCl can slow down this process. Over an eight-week period, we examined the aggregation rate, extinction behavior, and stability of gold, silver, and hybrid nanoparticles generated in different KCl concentrations. Extinction spectra, SEM images, SERS signal strength, and zeta potential were analyzed. Our results demonstrate that laser ablation in water and salt solutions yields nanoparticles with a spherical shape and a negative zeta potential. Importantly, we identified the optimal concentration of potassium chloride salt that maintains solution stability and SERS signal strength. Adsorbed chloride ions on silver nanoparticles were evidenced by low-frequency SERS band near 242 cm−1. A better understanding of the effect of KCl concentration on the properties of noble metal nanoparticles can lead to improved generation protocols and the development of tailored nanoparticle systems with enhanced stability and SERS activity.

In this work, electrochemical bioanalytical systems for the determination of antibodies against the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Spike protein (anti-rS) is reported. Environmentally friendly chemicals were applied in the synthesis of gold nanoparticles (AuNPs). The AuNPs were integrated onto the screen-printed carbon electrodes (SPE), and the biological recognition part was based on recombinant SARS-CoV2 Spike protein (rS), which during the immobilization was cross-linked by glutaraldehyde. Immobilized rS protein based biological recognition part enabled selective recognition of anti-rS antibodies. The current flux of AuNPs reduction (at +200 mV) in a pure phosphate buffer (PB) was employed as the transduction signal. It has been reported that the formation of anti-rS layers on the surface of AuNPs delays the electrode response time (ts), tracked at the current flux density values of 80 mu A cm-2. Using the AuNP-modified SPE, we demonstrated a rapid anti-rS detection within a detection limit of 2 ng mL-1 (0.125 binding antibody units mL-1, 17 pM). This system can be applied to track the response of immune system towards SARS-CoV-2 infection and monitoring of Coronavirus Disease 2019 (COVID-19).

Magneto-plasmonic nanoparticles were fabricated using a 1064 nm picosecond-pulsed laser for ablation of Fe/Au and Fe/Au/Fe composite thin films in acetone. Nanoparticles were characterized by electron microscopy, ultraviolet-visible (UV-VIS) absorption, and Raman spectroscopy. Hybrid nanoparticles were arranged on an aluminum substrate by a magnetic field for application in surface-enhanced Raman spectroscopy (SERS). Transmission electron microscopy and energy dispersive spectroscopy analysis revealed the spherical core-shell (Au-Fe) structure of nanoparticles. Raman spectroscopy of bare magneto-plasmonic nanoparticles confirmed the presence of magnetite (Fe3O4) without any impurities from maghemite or hematite. In addition, resonantly enhanced carbon-based bands were detected in Raman spectra. Plasmonic properties of hybrid nanoparticles were probed by SERS using the adsorbed biomolecule adenine. Based on analysis of experimental spectra and density functional theory modeling, the difference in SERS spectra of adsorbed adenine on laser-ablated Au and magneto-plasmonic nanoparticles was explained by the binding of adenine to the Fe3O4 structure at hybrid nanoparticles. The hybrid nanoparticles are free from organic stabilizers, and because of the biocompatibility of the magnetic shell and SERS activity of the plasmonic gold core, they can be widely applied in the construction of biosensors and biomedicine applications.

Group III–V semiconductor multi-junction solar cells are widely used in concentrated-sun and space photovoltaic applications due to their unsurpassed power conversion efficiency and radiation hardness. To further increase the efficiency, new device architectures rely on better bandgap combinations over the mature GaInP/InGaAs/Ge technology, with Ge preferably replaced by a 1.0 eV subcell. Herein, we present a thin-film triple-junction solar cell AlGaAs/GaAs/GaAsBi with 1.0 eV dilute bismide. A compositionally step-graded InGaAs buffer layer is used to integrate high crystalline quality GaAsBi absorber. The solar cells, grown by molecular-beam epitaxy, achieve 19.1% efficiency at AM1.5G spectrum, 2.51 V open-circuit voltage, and 9.86 mA/cm 2 short-circuit current density. Device analysis identifies several routes to significantly improve the performance of the GaAsBi subcell and of the overall solar cell. This study is the first to report on multi-junctions incorporating GaAsBi and is an addition to the research on the use of bismuth-containing III–V alloys in photonic device applications.

This is the first study reporting the presence of airborne nano-sized plastic particles in the bronchoalveolar lavage fluid (BALF) samples of patients undergoing diagnostic bronchoscopy. The results represent the plastic pollution content in the lower airways of the residents of Northern Europe. Airborne micro-and nanoplastic particles (MP/NPs) are widely dispersed worldwide and intrude on human organisms to various extents, with the respiratory tract being the first line of exposure. The amounts of inhaled MP/NPs, their fate in the human respiratory tract, and the effects on the health of human airways and other exposed organs remain largely unknown.In this clinical study, human BALF samples were assessed by means of optical and transmission electron microscopy coupled with energy-dispersive X-ray spectroscopy (TEM-EDX). Results show that MP/NPs levels vary in the interval of 0.14-12.8 particles per 100 ml of BALF and are present in all samples tested, mainly in a fragmented form. External pollution by MP/NPs was excluded by carefully choosing methodology and equipment. This finding is a timely addition of valuable information and stimulates further research into the biological effects of inhaled MP/NPs.

The particle number concentration (PNC), particulate matter (PM1) and black carbon (BC) mass concentration limits are not available from standard air quality monitoring networks as well as for indoor level standards in many countries. Total personal exposure is often disproportionately affected by the relatively short amount of time spent in office spaces and commuting trips. In this study, real-time measurements of PNC, PM1, and BC mass concentrations in the office and during commuting trips were performed to assess real-time employee personal exposure. Urban environments are very complex due to the different emission sources and their emission activities; therefore, a combination of mobile and stationary measurements allows for a better understanding of their dynamics and employee exposure, constituting a better predictor of health effects. Mobile measurements at the street level showed that the BC mass concentrations were the highest during peak hours, reaching up to 7.14 µg/m3 at hotspots. The hourly mean BC mass concentration in March 2022 at the urban background station ranged from 0.30 to 9.01 µg/m3, with traffic-related BC (BCtr) accounting for 66

We report a detailed characterization of five thermophilic bacteriophages (phages) that were isolated from compost heaps in Vilnius, Lithuania using Geobacillus thermodenitrificans strains as the hosts for phage propagation. The efficiency of plating experiments revealed that phages formed plaques from 45 to 80 °C. Furthermore, most of the phages formed plaques surrounded by halo zones, indicating the presence of phage-encoded bacterial exopolysaccharide (EPS)-degrading depolymerases. Transmission Electron Microscopy (TEM) analysis revealed that all phages were siphoviruses characterized by an isometric head (from ~63 nm to ~67 nm in diameter) and a non-contractile flexible tail (from ~137 nm to ~150 nm in length). The genome sequencing resulted in genomes ranging from 38,161 to 39,016 bp. Comparative genomic and phylogenetic analysis revealed that all the isolated phages had no close relatives to date, and potentially represent three new genera within siphoviruses. The results of this study not only improve our knowledge about poorly explored thermophilic bacteriophages but also give new insights for further investigation of thermophilic and/or thermostable enzymes of bacterial viruses.

Co2+:MgAl2O4 crystals are successfully used as passive Q-switches within the cavity of erbium glass lasers. Their limited resistance to laser radiation might also put constraints on the generated output peak power. Usually, polishing of optical substrates induces a contaminated Beilby layer and damages the subsurface layer, which leads to a considerably lower optical resistance of the obtained surface. Low-energy oxygen plasma etching using different depths of 50, 100, 250 and 400 nm was performed on polished crystals. The surface morphology by atomic force microscopy, transmission spectra, subsurface structure by transmission electron microscopy and the LIDT (R(1)-in-1) using 1540 nm nanosecond pulses were analyzed. It was demonstrated that plasma etching substantially increased the initial crystal surface LIDT. It also allowed the removal of the damaged subsurface layer and almost maintained the initial surface roughness. The presented results demonstrated the good potential of oxygen plasma etching for obtaining highly laser-damage-resistant Co2+:MgAl2O4 crystals for high-power laser applications.

A high temperature-adapted bacteriophage, vB_PtoS_NIIg3.2 (NIIg3.2), was isolated in Lithuania from compost heaps using Parageobacillus toebii strain NIIg-3 as a host for phage propagation. Furthermore, NIIg3.2 was active against four strains of Geobacillus thermodenitrificans, and it infected the host cells from 50 to 80 °C. Transmission electron microscopy analysis revealed siphovirus morphology characterized by an isometric head (~59 nm in diameter) and a noncontractile tail (~226 nm in length). The double-stranded DNA genome of NIIg3.2 (38,970 bp) contained 71 probable protein-encoding genes and no genes for tRNA. In total, 29 NIIg3.2 ORFs were given a putative functional annotation, including those coding for the proteins responsible for DNA packaging, virion structure/morphogenesis, phage–host interactions, lysis/lysogeny, replication/regulation, and nucleotide metabolism. Based on comparative phylogenetic and bioinformatic analysis, NIIg3.2 cannot be assigned to any genus currently recognized by ICTV and potentially represents a new one within siphoviruses. The results of this study not only extend our knowledge about poorly explored thermophilic bacteriophages but also provide new insights for further investigation and understanding the evolution of Bacilllus-group bacteria-infecting viruses.

The structures of the Caudovirales phage tails are key factors in determining the host specificity of these viruses. However, because of the enormous structural diversity, the molecular anatomy of the host recognition apparatus has been elucidated in only a number of phages. Klebsiella viruses vB_KleM_RaK2 (RaK2) and phiK64-1, which form a new genus Alcyoneusvirus according to the ICTV, have perhaps one of the most structurally sophisticated adsorption complexes of all tailed viruses described to date. Here, to gain insight into the early steps of the alcyoneusvirus infection process, the adsorption apparatus of bacteriophage RaK2 is studied in silico and in vitro. We experimentally demonstrate that ten proteins, gp098 and gp526-gp534, previously designated as putative structural/tail fiber proteins (TFPs), are present in the adsorption complex of RaK2. We show that two of these proteins, gp098 and gp531, are essential for attaching to Klebsiella pneumoniae KV-3 cells: gp531 is an active depolymerase that recognizes and degrades the capsule of this particular host, while gp098 is a secondary receptor-binding protein that requires the coordinated action of gp531. Finally, we demonstrate that RaK2 long tail fibers consist of nine TFPs, seven of which are depolymerases, and propose a model for their assembly.

The results of colossal magnetoresistance (CMR) properties of La0.83Sr0.17Mn1.21O3 (LSMO) films grown by pulsed injection MOCVD technique onto various substrates are presented. The films with thicknesses of 360 nm and 60 nm grown on AT-cut single crystal quartz, polycrystalline Al2O3, and amorphous Si/SiO2 substrates were nanostructured with column-shaped crystallites spread perpendicular to the film plane. It was found that morphology, microstructure, and magnetoresistive properties of the films strongly depend on the substrate used. The low-field MR at low temperatures (25 K) showed twice higher values (−31% at 0.7 T) for LSMO/quartz in comparison to films grown on the other substrates (−15%). This value is high in comparison to results published in literature for manganite films prepared without additional insulating oxides. The high-field MR measured up to 20 T at 80 K was also the highest for LSMO/quartz films (−56%) and demonstrated the highest sensitivity S = 0.28 V/T at B = 0.25 T (voltage supply 2.5 V), which is promising for magnetic sensor applications. It was demonstrated that Mn excess Mn/(La + Sr) = 1.21 increases the metal-insulator transition temperature of the films up to 285 K, allowing the increase in the operation temperature of magnetic sensors up to 363 K. These results allow us to fabricate CMR sensors with predetermined parameters in a wide range of magnetic fields and temperatures.