Search Results (60,139)

Open-source and commercial fifth-generation (5G) deployments are difficult to compare because they are built for different goals and reported under different conditions, which slows down validation and technology transfer from research to practice. This study explores the deployment and evaluation of two 5G Standalone (SA) disaggregated Radio Access Network (RAN) systems, using open-source research RAN, commercial RAN, and Software-Defined Radio (SDR) hardware. The first testbed is a SDR-based prototype, containing a Universal Software Radio Peripheral (USRP) B210 device, using Software Radio System RAN (srsRAN) as the RAN. The commercial-based testbed contains a Benetel RAN550 Radio Unit (RU), connected via an optical fiber to a Commercial Off-the-Shelf (COTS) server acting as the Distributed Unit (DU) and Centralized Unit (CU) using the Accelleran virtualized Baseband Unit (vBBU) platform. The Core Network (CN) is implemented using the open-source Open5GS in both testbeds. To evaluate the network’s functionality, throughput and latency are tracked using a Motorola Edge 50 Pro mobile terminal. The experimental results are analyzed and compared with representative performance metrics reported in the literature to place the measurements in a broader research context. This study further assesses trade-offs related to cost, portability, and scalability by comparing SDR-based research prototypes with commercial deployments. Full article

Non-arteritic ischemic optic neuropathy (NAION) results from vascular insufficiency within the optic nerve head. The precise pathogenesis of NAION remains unclear; however, insufficient blood supply from the short posterior ciliary arteries and the choroidal circulation has been associated with its development. Although major risk factors include diabetes, hypertension, and hyperlipidemia, coronavirus disease 2019 (COVID-19) may also contribute to the development of NAION. This literature review presents our case of NAION associated with COVID-19 infection and summarizes previously reported cases of NAION following COVID-19 infection published in the English-language literature worldwide. Because direct infection of ocular tissues, including ocular vessels, via the angiotensin-converting enzyme 2 receptor is thought to contribute to the development of NAION, cases of NAION associated with COVID-19 vaccination were excluded from this review. Furthermore, we discuss the possible molecular mechanisms underlying the development of NAION after COVID-19 infection and highlight the potential risks of COVID-19 for clinical ophthalmologists. Full article

Coloured and variegated leaves are common in shade-tolerant ornamentals. However, it remains unclear whether their photosynthetic performance is determined mainly by pigment abundance or by the organisation of chloroplasts and thylakoids. We tested this in three Epipremnum aureum phenotypes (‘Neon’, ‘Golden’ and ‘Jade’) that share a genetic background but contrast in leaf colour, chloroplast density and thylakoid membrane abundance. Plants were grown in a greenhouse and assessed by hyperspectral and thermal imaging, infrared gas exchange analysis, chlorophyll a fluorescence measurements, and structural, ultrastructural and biochemical analyses. Traits were integrated by principal component analysis, with the quantum yield of CO₂ assimilation per absorbed photon (αCO_2,abs) as the response variable. ‘Neon’ leaves had high specific leaf area and approximately 55% lower maximum Rubisco carboxylation (Vc_MAX) and electron transport capacity (J_MAX) than ‘Jade’, as well as reduced chloroplast and thylakoid abundance and warmer canopies, despite carotenoid enrichment. JIP-test parameters and fluorescence light–response curves showed high absorption and dissipation per PSII reaction centre, elevated excitation pressure, modest non-photochemical quenching (NPQ), low αCO_2,abs, small carbohydrate pools and low intrinsic water-use efficiency. ‘Jade’ leaves developed thick mesophyll with dense chloroplast populations, extensive thylakoid networks, highest NPQ, cool canopies and large carbohydrate reserves, whereas ‘Golden’ leaves combined thin laminae and intermediate chloroplast–thylakoid organisation with early light saturation of CO₂ assimilation and the highest intrinsic water-use efficiency. Principal component analysis revealed a structural axis of chloroplast and thylakoid organisation that better predicted αCO_2,abs, net carbon gain and canopy temperature than pigment abundance. In variegated E. aureum, ‘photon economy’ is therefore governed primarily by chloroplast and thylakoid membrane organisation and abundance rather than by carotenoid accumulation. Full article

Nondiffracting structured light has attracted considerable attention owing to broad applications in both the classical and quantum optics. Despite extensive research, existing generation approaches suffer from a contradiction between the subwavelength focal spot size and the strong side lobes, leading to a low-contrast localized light field in the far field. Here, we theoretically report a distinct technique for the generation of high-contrast nondiffracting structured light with its feature size reaching a subwavelength scale. The presented technique relies on a randomly perturbed sharp-edge aperture, which comprises a basic circular obstacle for exciting the in-phase high-spatial-frequency diffractive waves and randomized slit motifs for realizing destructive interference among the zero-order diffractive components, emerging from the sharp-edge diffraction. With this framework, we obtain a continuous high-contrast light needle, both for the zero-order light mode and the higher-order light with topological structure. In both cases, the resultant light fields preserve their subwavelength intensity profiles along propagation distance. This operating strategy provides an effective manner for structured light generation in the subwavelength scale, offering opportunities for advanced applications such as super-resolution imaging and nano-scale light–matter interaction. Full article

We investigate the optical response properties of an atom-assisted spinning optomechanical system, in which a spinning optical resonator is coupled simultaneously to a two-level atomic ensemble and a mechanical resonator driven by a weak pump field. Remarkably, we demonstrate that by simply reversing the rotation direction, the system can be switched between a low-absorption electromagnetic and optomechanically induced transparency state and a high-absorption state, constituting a form of non-reciprocal optical control at the quantum level. Furthermore, by tuning the phase difference between the mechanical pump and the probe field, direction-dependent switching between absorption and gain is achieved. These non-reciprocal effects originate from the Sagnac-induced frequency shift in the optical mode, which leads to distinct optomechanical and atom–cavity couplings for opposite spinning directions. We also show that the absorption spectrum can be modulated by the angular velocity and the atomic number. Our results indicate that the optical properties of the hybrid system can be manipulated via the angular velocity, phase difference, and atom number, with potential applications in chiral photonic communications. Full article

Interest in non-centrosymmetric crystalline materials exhibiting second harmonic generation (SHG) has increased due to their potential applications in optical sensing and biosensing. Saccharide-based metal complexes are particularly attractive systems, as chiral sugars can promote non-centrosymmetric crystal packing. In this work, a new lanthanum–β-d-fructose compound, [La(C₆H₁₂O₆)(H₂O)₅]Cl₃ (LaFRUCl), was synthesized using a simple and low-cost method and characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group P2₁2₁2₁ and consists of infinite (La³⁺–fructose)_n chains extending along the [001] direction, forming a one-dimensional Metal–Organic Framework. The nonlinear optical response was evaluated using the Kurtz–Perry powder technique with a Nd:YAG laser (1064 nm) and compared to a sucrose reference. The measured SHG efficiency is comparable to that of previously reported alkaline earth metal–sugar analogs. While the compound’s SHG emission is significant, evaluation of its structural stability under aqueous or physiological conditions is be required before considering biological applications. Full article

Stimulated Raman scattering (SRS) with Raman crystals is widely recognized as an effective technical approach for achieving high-efficiency lasers at specific wavelengths. However, due to crystal size limitations, it is challenging to generate large-energy Raman lasers while simultaneously considering the laser damage threshold of optical components. To overcome this limitation, in this paper we describe the successful fabrication of a large-aperture barium nitrate Raman gain medium using the directional template growth technique. Employing this large-aperture Raman medium and a 532 nm pulse laser as the excitation source, a large-energy, high-efficiency yellow–orange waveband laser system was constructed. When injected with 886.7 mJ pump energy at 532 nm, the Raman laser achieved a maximum output energy of 556.2 mJ, corresponding to an optical-to-optical conversion efficiency of 62.7%. This represents a significant advancement in single-pulse energy for barium nitrate Raman lasers. Large-energy yellow–orange wavelength lasers have applications in the clinical treatment of skin diseases and microfluidic chip manufacturing. Full article

Sand production in an offshore hydrocarbon wells poses significant operational and integrity challenges, particularly in deviated wells, where complex flow geometries intensify particle transport and erosion risks. The traditional sand-monitoring method utilizes stationary acoustic sensors attached to the production flowline at the surface. However, these sensors provide limited spatial coverage and intermittent measurements, restricting their ability to detect early sanding onset or precisely localize sanding intervals. By combining with vertical seismic profiling (VSP), Distributed Acoustic Sensing (DAS) delivers continuous, high-density data along the entire length of the wellbore and is increasingly recognized as a powerful diagnostic tool for real-time downhole monitoring. This study presents a field application of DAS-VSP for detecting and characterizing sand transport in a deviated offshore production well equipped with 350 distributed fiber-optic channels spanning 0–1983 m true vertical depth (TVD) at 8 m spacing. A multistage workflow was developed, including SEGY ingestion and shot merging, channel and time window selection, trace normalization, and low-pass filtering below 20 Hz. Multi-domain signal analysis, such as RMS energy, spike-based time-domain attributes, FFT, PSD spectral characterization, and time–frequency decomposition, were used to isolate the characteristic im-pulsive low-frequency (<20 Hz) signatures associated with sand impact. An adaptive thresholding and event-clustering scheme was then applied to discriminate sanding bursts from background noise and integrate their acoustic energy over depth. The processed DAS section revealed distinct, depth-localized sand ingress zones within the production interval (1136–1909 m TVD). The derived sand log provided a quantitative measure of sand intensity variations along the deviated wellbore, with normalized RMS amplitudes ranging from 0.039 to 1.000 a.u., a mean value of 0.235 a.u., and 137 analyzed channels within the production interval. These results indicate that sand production is highly clustered within discrete depth intervals, offering new insights into sand–fluid interactions during steady-state flow. Overall, the findings confirm that DAS-VSP enables continuous real-time monitoring of the sanding behavior with a far greater depth resolution than conventional tools. This approach supports proactive sand management strategies, enhances well-integrity decision-making, and underscores the potential of DAS to evolve into a standard surveillance technology for hydrocarbon production wells. Full article

As a response to aging of cultured urease-producing microorganisms, the blending method was examined to obtain the required carbonate production amount using the apparent viability (Rcv) based on previous research. As a result, a significantly higher carbonate content than the amount of CaCl₂ 2H₂O used was produced. Since this trend has been obtained in previous studies, it was judged that carbonate hydrate was formed. As a next step, a penetration test of soil–biocement–liquid (BCS) was conducted to investigate the properties and behavior of the BCS system, taking into account the microscopic properties of the BCS response. The depth distribution of carbonate content (C) was measured by the acid dissolution method of soil sampled from the specimen. It was assumed that the C-profile was formed by adsorption based on the diffuse double layer of microorganisms. It was shown that the amount of precursor-carbonate (precursor CPR), the optical density (OD) of viable bacteria, and the physical amount of soil adsorbed at that position can be estimated from C obtained at the various depths. In addition, the previously obtained formulas among CPR, viable OD, and Rcv shown are briefly explained in this paper. Full article

Ice clouds play a significant role in the Earth’s radiation balance due to their unique microphysical and radiative properties, which vary with formation mechanisms and regions and influence the local energy budget. In this study, six years of Ka-band Zenith Radar (KAZR) observations from the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL) and the Southern Great Plains (SGP) sites, combined with the Fu–Liou radiative transfer model, were used to examine the macrophysical and microphysical properties of ice clouds, their radiative effects, and contributions to the surface energy budget. The results show that the frequency of ice cloud occurrence at SACOL is 40%, significantly higher than the 27% observed at SGP. At both sites, ice cloud altitudes exhibit an increasing trend in the context of recent warming, with a more pronounced increase at SGP. Seasonal variations are evident, with spring characterized by relatively thick and widespread ice clouds, while summer is dominated by high-altitude, optically thin clouds. Ice cloud occurrence peaks at night and decreases during the day at both sites; however, cloud diurnal variations in summer are much greater at SGP than at SACOL. Radiative analysis indicates that longwave radiation-induced warming dominates ice cloud radiative forcing. Net radiative forcing at the top of the atmosphere is 6.08 W/m² at SACOL and 3.06 W/m² at SGP, contributing to atmospheric heating within and beneath cloud layers. At the surface, sensible heat dominates the energy budget at SACOL (over 63%) due to its arid climate, whereas latent heat dominates at SGP (about 67%) because of abundant moisture; and ice clouds have the greatest impact in winter, reducing surface net radiation by 29% at SACOL and 26% at SGP, producing a cooling effect. Full article

The ability to assess molecular binding kinetics in real time is critical for advancing our understanding of molecular interactions in biochemical and biotechnological systems. This work presents a novel optical tweezer (OT)-based method to monitor molecular affinity in real time, focusing on the high-affinity streptavidin–biotin system as a model. Transparent poly(methyl methacrylate) (PMMA) microparticles functionalized with streptavidin were trapped before, during, and after binding with biotinylated bovine serum albumin (biotin–BSA), enabling the analysis of forward-scattered signals to detect nanoscale changes in particle size. By applying the Power Spectral Density method, the friction coefficient of individual particles was calculated, allowing for real-time tracking of binding dynamics and the estimation of the association rate constant ($k_{\mathrm{on}}\approx {10}^6{\mathrm{M}}^{-1}{\mathrm{s}}^{-1}$). These results are consistent with literature values and demonstrate the potential of this OT-based approach for non-invasive, label-free detection of molecular interactions. Compared to existing techniques, such as atomic force microscopy and cantilever-based sensors, this method offers significant advantages, including real-time monitoring, adaptability to different bioaffinity systems, and compatibility with miniaturized setups. This work establishes a foundation for using OT-based tools to monitor high-affinity molecular interactions in real time. While demonstrated here using biotinylated BSA as a model ligand, future studies will explore the method’s applicability to smaller ligands and more subtle surface modifications. Full article

The preparation of the novel optically active sulfoxides (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(p-tolylsulfinyl)phenyl]propan-2-ol 1, (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(methylsulfinyl)phenyl]propan-2-ol 2 and (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(t-butyl-sulfinyl)phenyl]propan-2-ol 3 according to the Andersen methodology and their spectroscopic characterization is presented. The NMR and CD spectroscopic evidence of the existence of the equilibrium between sulfoxide and hypervalent sulfurane forms of these compounds in solution and attempts at the isolation of corresponding sulfuranes are shown. For compound 3, the unprecedented subsequent irreversible transformation in solution into corresponding cyclic sulfinate ester–sultine 17 was established on the basis of NMR spectroscopy measurements. The mechanism of this transformation was investigated by means of GC-MS analysis and confirmed on the basis of synthesized long alkyl chain analog 23 transformation in solution. Moreover, the oxidation properties of obtained sulfoxides 2 and 3 for the selected compounds are described. Full article

Background: The aim of this study was to evaluate the influence of demographic, clinical and physical factors on the occurrence of ocular complications after ruthenium-106 (Ru-106) brachytherapy, iodine-125 (I-125) brachytherapy and proton therapy of uveal melanoma. Methods: A retrospective analysis of 300 patients’ electronic and paper medical records treated for uveal melanoma at the Department of Ophthalmology and Ocular Oncology, University Hospital in Krakow, Poland, from May 2014 to December 2016 was performed. The created database, which includes numerous parameters characterizing patients, tumors, applied treatments and their effects, with particular emphasis on the occurrence of ocular complications, was subjected to detailed analysis. The influence of selected factors on the occurrence of identified complications was checked by performing a univariable Cox proportional hazards regression analysis, and then the factors that were statistically significant were included in a multivariable Cox proportional hazards regression analysis which gave the final results. Results: Of the 300 patients, 125 (41.67%) were treated with Ru-106 brachytherapy (87 (29%) with CCB plaque and 38 (12.67%) with COB plaque), 102 (34%) with I-125 brachytherapy and 73 (24.33%) with proton therapy. Mean follow-up was 88.63 months (median 89, range: 20–127). The occurrence of cataract was associated with the older age of patients. Maculopathy was associated with female sex, younger age, use of I-125 brachytherapy, tumor location involving the macula and/or optic disc and moderate tumor pigmentation. Diagnosis of systemic hypertension was associated with a lower risk of maculopathy. Retinopathy was associated with younger age, tumor location involving the macula and/or optic disc and the use of I-125 brachytherapy. Optic neuropathy was associated with younger age, greater tumor largest base diameter, tumor location involving the macula and/or optic disc and the use of I-125 brachytherapy. Secondary glaucoma was associated with baseline best corrected visual acuity (BCVA) weaker than 0.5, greater tumor thickness, involvement of the left eye and the use of I-125 brachytherapy. Vitreous hemorrhage was associated with greater tumor thickness, tumor location including the macula and/or optic disc and mushroom-shaped tumor. Conclusions: Our study demonstrated an association between demographic, clinical, and physical factors and the occurrence of ocular complications after radiotherapy for uveal melanoma. Full article

Boriding is a thermochemical process that improves the surface properties of metallic materials, such as wear resistance, hardness, and Young’s modulus. The current work evaluated the kinetics of boride layers formed by boriding on AISI H13 steel. The AISI H13 steel samples were covered with a non-commercial powder mixture of 70% wt. SiC, 20% B₄C wt. and 10% wt. KBF₄. The samples were treated for 2, 4, and 6 h at 850, 875, and 900 °C, respectively. The growth kinetics of boride layers were estimated as a function of the treatment parameters, using a solution of the second Fick’s Law, as in a parabolic model. Also, the hardness of layers was assessed by Vickers microindentation. Optical examination of the samples showed a biphasic FeB/Fe₂B layer at all temperatures after 6 h of treatment. In contrast, those exposed for 2 h exhibited a monophasic Fe₂B layer with isolated zones of the FeB phase in all temperatures. The results suggested that the obtained layer thicknesses are highly dependent on the treatment parameters. After 2 h at 850 °C, the samples exhibited a well-defined layer with a thickness of 8.51 ± 1.01 μm, whereas after 6 h it was 24.39 ± 1.01 μm. The activation energy was estimated at 230.63 kJ/mol, with a correlation coefficient (R2) of 0.97, consistent with values reported in the literature. Additionally, the hardness values were estimated to range from 1880 to 2192 HV for the FeB phase and from 1294 to 1715 HV for the Fe₂B phase, indicating that the hardness of the boride layers is highly dependent on the treatment conditions. Full article

Nanopositioning systems (NPS) are used in various fields of technology, such as micro- and nanoelectronics, optics, and biotechnology, where demands for higher dynamic performance and sub-nanometer accuracy are continuously increasing. Thus, the determination and compensation of stress-induced negative impacts on the systems gain significance to ensure accurate positioning. Major contributors are temperature gradients. Hence, understanding and predicting temperature changes is crucial for improving such systems. This work focuses on a substructure of an NPS drive system consisting of coil assemblies. This substructure serves as a primary heat source due to the occurrence of ohmic losses, leading to an increase in temperature and therefore significantly influencing the thermal deformation. The aim of this paper is to compose a CFD model with reduced submodels of the coil assembly, which, in comparison to experimental validation data, predicts its temperature development with satisfactory accuracy. By simplification of the system through a number of sub-models, computational effort is significantly lowered. The reduced CFD model not only enables efficient thermal analysis of the coil assembly but also provides a practical approach for broader use in system design and optimization, where fast and reliable thermal predictions are essential. Full article