Search Results (5)

Background: Inter-limb asymmetry has implications for both athletic performance and healthcare practice. High baseline inter-limb asymmetries have been associated with impaired mobility, increased fall risk, and musculoskeletal injuries across the lifespan. Exercise interventions able to stimulate the stretch–shortening cycle (e.g., plyometric training and jump training) have been shown to have a good impact on asymmetries. Among these, Mini-Trampoline Training (MTT) has recently emerged as potentially effective in reducing asymmetries. Objectives: The study aimed to evaluate the acute effects of a single MTT session on muscle power and inter-limb asymmetry in young adults. Methods: Twenty-eight recreationally active participants (25.6 ± 2.4 years) completed one MTT session. Before (PRE) and after (POST) the MTT session, single-leg 6 m Timed Hop (6MTH) and countermovement jump (CMJ) tests were administered. Additionally, 6MTH values of the dominant (DOM) and non-dominant (NODOM) limbs were used to stratify participants according to higher (HBIA) or lower (LBIA) baseline inter-limb asymmetry, based on a commonly adopted Normalized Symmetry Index (NSI) threshold (NSI ≥ 10%, n = 12; NSI < 10%, n = 16). Repeated-measures mixed models were used to evaluate the effects of the MTT session on 6MTH, NSI, and CMJ. Results: Regardless of group and limb, significant (p < 0.0001) improvements in 6MTH (PRE: 2.5 ± 0.06 s; POST: 2.3 ± 0.05 s) were found. Interestingly, the MTT session had a significant (p = 0.01) effect on both groups, with a significant (p = 0.003) interaction with NSI values, showing an improvement for HBIA (PRE = 15.4 ± 1.1%, POST = 11.3 ± 2.1%), whereas a decrement in LBIA was recorded (PRE = 5.1 ± 0.6%, POST = 9.6 ± 1.5%). CMJ did not show any changes in HBIA (PRE: 36.2 ± 0.9 cm; POST: 35.1 ± 0.7 cm), while a significant (p = 0.007) decrease was found in LBIA (PRE: 34.8 ± 1.2 cm; POST: 33.2 ± 1.3 cm). Conclusions: A single MTT session induced acute neuromuscular fatigue, reflected by reduced CMJ performance and improved (~8%) inter-limb control during hopping. The HBIA group preserved jump height (~36 cm) and demonstrated a significant reduction in asymmetry (NSI: −4.1%), suggesting more balanced lower-limb recruitment. Conversely, LBIA showed a significant decrease in CMJ and an increased NSI (+4.5%), possibly reflecting fatigue-related compensatory strategies. Overall, a single MTT elicited distinct responses according to baseline asymmetry, supporting its potential as an adaptable modality for enhancing neuromuscular function in HBIA. Full article

A sensitive non-contact sensing system based on the CoFeNiSiB amorphous ribbon giant magnetoimpedance (GMI) effect is proposed for current testing. The sensing system consists of a GMI probe, a sinusoidal current generator, a voltage follower, a preamplifier, a low-pass filter, and a peak detector. Four different GMI probes derived from amorphous ribbon meanders are designed and fabricated through MEMS processes. GMI probes were driven by a 10 MHz, 5 mA AC current. A permanent magnet was used to provide a bias magnetic field for the probe. The effect of the bias magnetic field on the output DC voltage was investigated. This non-contact current sensing system exhibits good sensitivity and linearity at a bias magnetic field H_bias = 15 Oe. The sensitivity can reach up to 24.2 mV/A in the ±1.5 A range. Full article

Wireless sensor network (WSN) deployment is an intensive field of research. In this paper, we propose a novel approach based on machine learning (ML) and metaheuristics (MH) for supporting decision-makers during the deployment process. We suggest optimizing node positions by introducing a new hybridized version of the “Hitchcock bird-inspired algorithm” (HBIA) metaheuristic algorithm that we named “Intensified-Hitchcock bird-inspired algorithm” (I-HBIA). During the optimization process, our fitness function focuses on received signal maximization between nodes and antennas. Signal estimations are provided by the machine learning “K Nearest Neighbors” (KNN) algorithm working with real measured data. To highlight our contribution, we compare the performances of the canonical HBIA algorithm and our I-HBIA algorithm on classical optimization benchmarks. We then evaluate the accuracy of signal predictions by the KNN algorithm on different maps. Finally, we couple KNN and I-HBIA to provide efficient deployment propositions according to actual measured signal on areas of interest. Full article

Poppers are legal and largely used in France despite severe side effects, such as methaemoglobinaemia (MetHbia). Our work aimed to assess the prevalence of poppers consumers among patients with a MetHbia higher than or equal to 5% in French university hospitals and its evolution before and after the legalization of poppers in France. We conducted a national multicentre observational retrospective study. All patients for whom at least one MetHbia measurement was performed from 2012 to 2017 in university hospitals where the French addictovigilance network (FAN) is implanted were included. For each MetHbia measurement exceeding or equal to 5%, a return to the clinical file was made by the FAN to assess poppers consumption. We calculated the prevalence of MetHbia exceeding or equal to 5% and 25% and the prevalence of poppers consumption before and after the legalization. A total of 239 (0.14%) patients had a MetHbia level exceeding or equal to 5% with 25 (10.46%) cases of poppers consumption. Poppers consumption represented 68.4% (13 out of 19) of cases with MetHbia greater than or equal to 25%. Poppers consumption among patients with MetHbia exceeding or equal to 5% increased after the legalization from 4.76% to 11.67% (prevalence ratio PR = 2.45, 95% CI = [0.98–8.37], p-value = 0.190). The proportion of patients with a MetHbia level of 25% or more increased after the legalization from 4.76% to 8.63% (PR = 1.81, 95% CI = [0.68–6.82], p-value = 0.374). The use of poppers is very frequently reported by patients with MetHbia greater than or equal to 25%. Full article

This paper describes the modeling of magnetoelectric (ME) effects for disk-type Terfenol-D (Tb_0.3Dy_0.7Fe_1.92)/PZT (Pb(Zr,Ti)O₃) laminate composite at low frequency by combining the advantages of the static elastic model and the equivalent circuit model, aiming at providing a guidance for the design and fabrication of the sensors based on magnetoelectric laminate composite. Considering that the strains of the magnetostrictive and piezoelectric layers are not equal in actual operating due to the epoxy resin adhesive bonding condition, the magnetostrictive and piezoelectric layers were first modeled through the equation of motion separately, and then coupled together with a new interface coupling factor k_c, which physically reflects the strain transfer between the phases. Furthermore, a theoretical expression containing k_c for the transverse ME voltage coefficient α_v and the optimum thickness ratio n_optim to which the maximum ME voltage coefficient corresponds were derived from the modified equivalent circuit of ME laminate, where the interface coupling factor acted as an ideal transformer. To explore the influence of mechanical load on the interface coupling factor k_c, two sets of weights, i.e., 100 g and 500 g, were placed on the top of the ME laminates with the same thickness ratio n in the sample fabrication. A total of 22 T-T mode disk-type ME laminate samples with different configurations were fabricated. The interface coupling factors determined from the measured α_v and the DC bias magnetic field H_bias were 0.11 for 500 g pre-mechanical load and 0.08 for 100 g pre-mechanical load. Furthermore, the measured optimum thickness ratios were 0.61 for k_c = 0.11 and 0.56 for k_c = 0.08. Both the theoretical ME voltage coefficient α_v and optimum thickness ratio n_optim containing k_c agreed well with the measured data, verifying the reasonability and correctness for the introduction of k_c in the modified equivalent circuit model. Full article