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Barium titanate (BaTiO3) is a lead-free ferroelectric crystal used in electro-mechanical transducers and electro-optic films. Nanomechanical devices based on thin films of BaTiO3 are still unavailable, as the internal stress of thin ferroelectric films results in brittle fracture. Here, we use the electro-mechanical force to fabricate deformable assemblies (nanobeams) of BaTiO3 nanocrystals, on top of plasmonic metasurfaces. The mechanical deformation of the nanobeams is driven by the piezoelectric response of the BaTiO3 nanocrystals. The plasmonic-ferroelectric nanostructures due to the plasmonic enhancement enable subwavelength interaction lengths and support reflection modulation up to 2.936 ± 0.008%. Their frequency response is tested across 50 kHz up to 2 MHz and is dependent on the mechanical oscillations of the deformable BaTiO3 nanobeams. The ferroelectric nanobeams support mechanical nonlinearities, which offer additional control over the electro-mechanical to optical conversion.

We report on the generation of photon pairs at 1550 nm from free-standing epitaxially grown self-assisted micrometre long GaAs nanowires. The efficiency of the spontaneous parametric down-conversion process has a rate of 320 GHz/Wm normalized to the transmission of the setup, the pump intensity, and the volume of the nanostructure. GaAs is a high index dielectric that can support electromagnetic Mie modes, therefore we model how shorter nanowires could improve the second-harmonic signal and we found that sub-micro long nanowires (600 nm length and 250 nm diameter) can support quality factors up to 15 at the pump wavelength (780 nm). We anticipate that the near field enhancement compared to micrometre long nanowires will boost the second-harmonic generation and, correspondingly, the biphoton rate efficiency.

Abstract Per- and polyfluoroalkyl substances (PFAS) pose an emerging environmental risk impacting food products and ecosystems. This study analyzes over 150,000 entries from food safety authorities and scientific publications from 2017 onwards. Our findings show that fish & seafood, and biota have the highest PFAS concentrations due to environmental contamination and bioaccumulation. Surface water samples also frequently contain PFAS, raising concerns about long-term ecological and human health effects. Comprehensive strategies are essential to mitigate these risks.

We present the design and fabrication advances on active lithium niobate metasurfaces. We determine by numerical calculations a metasurface design with electro-magnetic resonances in the visible and near-infrared, by taking into account the constraints for fabrication on thin films of lithium niobate. We suggest that the optical properties of the metasurface can be switched using the electro-optical properties of lithium niobate.

Abstract We introduce a novel, gaseous target optical shaping laser set-up, capable to generate short scale length, near-critical target profiles via generated colliding blast waves. These profiles are capable to maintain their compressed density for several nanoseconds, being therefore ideal for laser-plasma particle acceleration experiments in the near critical density plasma regime. Our proposed method overcomes the laser-target synchronization limitations and delivers energetic protons, during the temporal evolution of the optically shaped profile, in a time window of approximately 2.5 ns. The optical shaping of the gas-jet profiles is optimised by MagnetoHydroDynamic simulations. 3D Particle-In-Cell models, adopting the spatiotemporal profile, simulate the 45 TW femtosecond laser plasma interaction to demonstrate the feasibility of the proposed proton acceleration set-up. The optical shaping of gas-jets is performed by multiple, nanosecond laser pulse generated blastwaves. This process results in steep gradient, short scale length plasma profiles, in the near critical density regime allowing operation at high repetition rates. Notably, the Magnetic Vortex Acceleration mechanism exhibits high efficiency in coupling the laser energy into the plasma in the optically shaped targets, resulting to collimated proton beams of energies up to 14 MeV.

Background: Parathyroid adenoma is the most common cause of hypercalcemia and rarely leads to a hypercalcemic crisis, which is an unusual endocrine emergency that requires timely surgical excision. Case presentation: A 67-year-old male was admitted to the ER of the Euroclinic Hospital, Athens, Greece, because of elevated calcium levels and a palpable right-sided neck mass, which were accompanied by symptoms of nausea, drowsiness, and weakness for six months that increased prior to our evaluation. A gradual creatinine elevation and decreasing mental state were observed as well. The initial laboratory investigation identified severely elevated serum calcium (3.6 mmol/L) levels consistent with a hypercalcemic crisis (HC) and parathyroid hormone PTH (47.6 pmol/L) due to primary hyperparathyroidism. Neck ultrasonography (USG) identified a large, well-shaped cystic mass in the right thyroid lobe. With a serum calcium concentration of 19.5 mg/dL and a PTH of 225.3 pmol/L, the patient underwent partial parathyroidectomy and total thyroidectomy, which decreased serum calcium and PTH to 2.5 mmol/L and 1.93 pmol/L, respectively. Histology revealed a giant intrathyroidal cystic parathyroid adenoma, which was responsible for the hypercalcemic crisis. Postoperatively, the patient developed severe biochemical and clinical hypocalcemia, with calcium concentrations as low as 1.65 mmol/L, consistent with hungry bone syndrome (HBS), which was treated with high doses of intravenous calcium gluconate and oral alfacalcidol, and a slow recovery of serum calcium. After discharge, parathyroid function recovered, and symptomatology resolved entirely in more than one month. Discussion/conclusions: We present a case involving an exceptionally large intrathyroidal parathyroid adenoma that is characterized by clinical manifestations that mimic malignancy. The identification and treatment of such tumors is challenging and requires careful preoperative evaluation and postoperative care for the risk of hungry bone syndrome.

Radial basis function networks are widely used in a multitude of applications in various scientific areas in both classification and data fitting problems. These networks deal with the above problems by adjusting their parameters through various optimization techniques. However, an important issue to address is the need to locate a satisfactory interval for the parameters of a network before adjusting these parameters. This paper proposes a two-stage method. In the first stage, via the incorporation of grammatical evolution, rules are generated to create the optimal value interval of the network parameters. During the second stage of the technique, the mentioned parameters are fine-tuned with a genetic algorithm. The current work was tested on a number of datasets from the recent literature and found to reduce the classification or data fitting error by over 40% on most datasets. In addition, the proposed method appears in the experiments to be robust, as the fluctuation of the number of network parameters does not significantly affect its performance.

The Grammatical Evolution technique has been successfully applied to a wide range of problems in various scientific fields. However, in many cases, techniques that make use of Grammatical Evolution become trapped in local minima of the objective problem and fail to reach the optimal solution. One simple method to tackle such situations is the usage of hybrid techniques, where local minimization algorithms are used in conjunction with the main algorithm. However, Grammatical Evolution is an integer optimization problem and, as a consequence, techniques should be formulated that are applicable to it as well. In the current work, a modified version of the Simulated Annealing algorithm is used as a local optimization procedure in Grammatical Evolution. This approach was tested on the Constructed Neural Networks and a remarkable improvement of the experimental results was shown, both in classification data and in data fitting cases.

The Grammatical Evolution technique has been successfully applied to some datasets from various scientific fields. However, in Grammatical Evolution, the chromosomes can be initialized at wide value intervals, which can lead to a decrease in the efficiency of the underlying technique. In this paper, a technique for discovering appropriate intervals for the initialization of chromosomes is proposed using partition rules guided by a genetic algorithm. This method has been applied to feature construction techniques used in a variety of scientific papers. After successfully finding a promising interval, the feature construction technique is applied and the chromosomes are initialized within that interval. This technique was applied to a number of known problems in the relevant literature, and the results are extremely promising.

Methanol has been identified as a transition fuel for the decarbonisation of combustion-based industries, including automotive and maritime. This study aims to conduct a critical review of methanol combustion in compression ignition engines and analyse the reviewed studies’ results to quantify methanol use’s impact on engine performance and emissions characteristics. The diesel and diesel–methanol operation of these engines are comparatively assessed, demonstrating the trade-offs between the methanol fraction, the key engine performance parameters, including brake thermal efficiency, peak in-cylinder pressure, heat release rate, and temperature, as well as the carbon dioxide, carbon monoxide, nitrogen oxides, and particulate matter emissions. The types of the reviewed engines considering the main two combustion methods, namely premixed and diffusion combustion, are discussed. Research gaps are identified, and recommendations for future research directions to address existing challenges for the wider use of methanol as a marine fuel are provided. This comprehensive review provides insights supporting methanol engine operation, and it is expected to lead to further studies towards more efficient use of methanol-fueled marine engines.

Background: Vitamin D testing (VDT) and supplement use (VDS) are on the rise, but most patients remain deficient (3000 IU/day)), intake duration (short-term (2; never users: n = 5553 (80.3%), former users: n = 533 (7.7%), current users: n = 826 (12.0%). Current use of VDS was higher in females. VDT rose from 42.1% in 2014 to 92.7% in 2022, and VDA rose from 14.8% to 25.5% for the same time. VDA was found overall in n = 1511 (21.9%); Never users: n = 864 (15.6%), Former users: n = 123 (23.2%); and Current users: n = 370 (44.8%). The maximal VDA (67.9%) was found in subjects using high-dose VDS in the long term. Conclusions: Despite the significant rise in VDT and VDS use, VDA was found in a minority of patients. Prolonged use of high-dose supplements produces modest improvements in VDA.