Search Results (4)

Every day, millions of meteoroids enter the atmosphere and ablate, forming a long plasma trail. It is a strongly scattering object for electromagnetic waves and can be effectively detected by meteor radar at altitudes between 70 km and 140 km. Its echo typically has Fresnel oscillation characteristics. Most of the traditional detection methods rely on determining the threshold value of the signal-to-noise ratio (SNR) and solving parameters to recognize meteor echoes, making them highly susceptible to interference. In this paper, a neural network model, YOLOv8n-BP, was proposed for detecting the echoes of underdense meteors by identifying them from their echo characteristics. The model combines the strengths of both YOLOv8 and back propagation (BP) neural networks to detect underdense meteor echoes from Range-Time-Intensity (RTI) plots where multiple echoes are present. In YOLOv8, the n-type parameter represents the lightweight version of the model (YOLOv8n), which is the smallest and fastest variant in the YOLOv8 series, specifically designed for resource-constrained scenarios. Experiments show that YOLOv8n has excellent recognition ability for underdense meteor echoes in RTI plots and can automatically extract underdense meteor echoes without the influence of radio-frequency interference (RFI) and disturbance signals. Limited by the labeling error of the dataset, YOLOv8 is not precise enough in recognizing the head and tail of meteors in the radar echograms, which may result in the extraction of imperfect echoes. Utilizing the Fresnel oscillation properties of meteor echoes, a BP network based on a Gaussian activation function is designed in this paper to enable it to detect meteor head and tail positions more accurately. The YOLOv8n-BP model can quickly and accurately detect and extract underdense meteor echoes from RTI plots, providing correct data for meteor parameters such as radial velocities and diffusion coefficients, which are used to allow wind field calculations and estimate atmospheric temperature. Full article

(1) Introduction: Adiponectin is synthetized by white adipose tissue and has anti-diabetic, anti-atherosclerotic, anti-thrombotic, anti-inflammatory, and cardioprotective properties. In patients with arterial hypertension, plasma concentration of adiponectin is lower than in healthy subjects. Renal denervation, i.e., percutaneous ablation of fibers from the sympathetic nervous system located in the wall of the renal arteries by radio frequency waves, is a method of resistant arterial hypertension treatment. (2) The aim of this single center, interventional, clinical study was to assess the effect of renal denervation on the plasma adiponectin concentration in patients with resistant arterial hypertension. (3) Materials and methods: 28 patients (13 women, 15 men) aged 54.4 ± 9.2 years with resistant hypertension who underwent renal denervation using Simplicity catheters (Medtronic, Inc., Northridge, CA, USA) were enrolled in the study. Plasma adiponectin concentration was determined using the Human Adiponectin ELISA Kit (Otsuka Pharmaceutical Co, Tokyo, Japan) before the renal denervation and 6 and 12 months after this procedure. (4) Results: Blood pressure (BP) values before renal denervation and 6 and 12 months after this procedure were as follows: systolic BP 190.4 ± 24.5, 160.8 ± 14.5, 155.7 ± 17.9 mmHg (p < 0.001) and diastolic BP 111.7 ± 18.9, 88.9 ± 8.3, 91.2 + 10.2 mmHg (p < 0.001), respectively. Body mass index (BMI) before renal denervation, 6 and 12 months after this procedure were 31.5 ± 4.2, 30.5 ± 4.4, 30.2 ± 4.0 kg/m², (p = 0.057), respectively. Plasma adiponectin concentration before the renal denervation and 6 and 12 months after this procedure were 4.79 (3.95; 9.49), 7.58 (5.04; 9.51), 6.62 (4.57; 11.65) [µg/mL] (p = 0.007), respectively. (5) Conclusions: Plasma adiponectin concentration increases significantly after successful renal denervation in patients with resistant hypertension. Higher plasma adiponectin concentration may participate—beyond blood pressure reduction—in the cardiovascular benefits related to successful renal denervation; however’ clinical consequences of these results need further investigations. Full article

During the pulsed laser ablation of metals, as well as other materials, the development of a plasma plume close to the ablated surface leads to the emission of radio frequency energy. In this paper, we describe a process for analysing the received radio frequency power (RFP) for an aluminium (Al) surface ablation process in atmosphere using picosecond laser pulses at a wavelength of 1064 nm. The analysis of the RFP was carried out on two sets of experiments, where two parameters of the laser (repetition rate of laser (RRL) and power of laser (PL)) were varied while other parameters remained constant. In addition to the RFP measurement during the laser processing, the spatter area (SA), which is defined in this paper, and the depth of the ablated hole were measured post-process using a 3D microscope. It was observed that there is a direct relationship between (RFP)² and SA. Accordingly, an appropriate RF calibration was performed, which leads to the definition of a quantity called the RF regulation % (RFR%). By comparing the RFR and PL/RRL variations, to which the laser beam fluence is proportional in these experiments, a diagnostic process (i.e., flowchart) for real-time depth evaluation was proposed and experimentally confirmed. This diagnostic process can indicate if the depth of the laser ablated crater is less than or exceeds a predetermined depth, which in this study was set to 15 µm. It is also demonstrated that the SA variation can be estimated in real-time by analysing the received RF power and, secondly, the depth of ablation can be measured in real time using a combination of information from the received RF power and laser parameters. Full article

Scars are a common disfiguring sequela of various events such as acne, hidradenitis suppurativa, surgery, trauma, and burns, which can lead to serious psychosocial problems with a negative effect on the quality of life. Many conventional approaches have been proposed for the treatment of scars, including surgical techniques, dermabrasion, chemical peels, topical silicone gel, 5-fluorouracile and dermal fillers injection or autologous fat transfer for atrophic scars, and corticosteroids injection for hypertrophic and keloid scars; however, they have sporadic effects. Ablative lasers, such as carbon dioxide laser or Erbium Yag laser, are associated with many collateral effects limiting their application. Non-ablative laser treatments have been shown to be safer and to have fewer side effects, but they have a reduction of clinical efficacy compared to ablative lasers and a minimal improvement of scars. The demand for minimal invasive and safe technology for the treatment of a scars has stimulated the search for more effective novel therapy with fewer collateral effects. Plasma radiofrequency ablation is a new technique consisting of the generation of plasma energy through the production of ionized energy, which thermally heats tissue in a uniform and controlled manner, through a plasma radiofrequency device, inducing a sublimation of the tissue. The aim of this study is to evaluate the effectiveness of P-RF ablation in the treatment of scars performed with D.A.S. Medical device (Technolux, Italia), which is a tool working with the long-wave plasma radiofrequency principle. Full article