16 research outputs found
Experimental Characterization of Ionic Polymer Metal Composite as a Novel Fractional Order Element
Ionic polymer metal composites (IPMCs) are electroactive materials made of ionic polymer thin membranes with platinum metallization on their surfaces. They are interesting materials due to not only their electromechanical applications as transducers but also to their electrochemical features and the relationship between the ionic/solvent current and the potential field. Their electrochemical properties thus suggest the possibility for exploiting them as compact fractional-order elements (FOEs) with a view of defining fabrication processes and production strategies that assure the desired performances. In this paper, the experimental electrical characterization of a brand new IPMC setup in a fixed sandwich configuration is proposed. Two IPMC devices with different platinum absorption times (5 h and 20 h) are characterized through experimental data: first, a preliminary linearity study is performed for a fixed input voltage amplitude in order to determine the frequency region where IPMC can be approximated as linear; then, a frequency analysis is carried out in order to identify a coherent fractional-order dynamics in the bode diagrams. Such analyses take the first steps towards a simplified model of IPMC as a compact electronic FOE for which the fractional exponent value depends on fabrication parameters as the absorption time
The effects of creatine supplementation combined with resistance training on regional measures of muscle hypertrophy: a systematic review with meta-analysis.
The purpose of this paper was to carry out a systematic review with meta-analysis of randomized controlled trials that examined the combined effects of resistance training (RT) and creatine supplementation on regional changes in muscle mass with direct imaging measures of hypertrophy. Moreover, we performed regression analyses to determine the potential influence of covariates. We included trials of at least 6 weeks in duration that examined the combined effects of creatine supplementation and RT on site-specific direct measures of hypertrophy (magnetic resonance imaging [MRI], computed tomography [CT] or ultrasound) in healthy adults. A total of 44 outcomes were analyzed across 10 studies that met inclusion criteria. Univariate analysis of all standardized outcomes showed a pooled mean estimate of 0.11 (95% Credible Interval [CrI]: -0.02 to 0.25) providing evidence of a very small effect favoring creatine supplementation when combined with RT, compared to RT and placebo. Multivariate analyses found similar small benefits for the combination of creatine supplementation and RT on changes in upper and lower body muscle thickness (0.10-0.16 cm). Analyses of moderating effects indicated a small superior benefit for creatine supplementation on younger compared to older adults (0.17 [95% CrI: -0.09 to 0.45]). In conclusion, results suggest that creatine supplementation combined with RT promotes a small increase in direct measures of skeletal muscle hypertrophy in both the upper and lower body
EXplainable AI for Decision Support to Obesity Comorbidities Diagnosis
This paper describes the implementation of a comprehensive clinical decision support system (CDSS) for the risk factors prediction of comorbidities related to obesity and for the characterization of indirect connections between such comorbidities and non-communicable diseases. In particular, the direct correlation between obesity, diabetes, cardiovascular, and heart disease is analyzed by using machine learning (ML) predictive models, while the connection of the co-occurring disorders to the numerous additional non-communicable diseases is analyzed via a graph-based user interface. The CDSS here proposed is, therefore, structured with three main components: ML predictive models based on publicly available datasets, explainable artificial intelligence (XAI) local and global model interpretation, and graph-based representation of non-communicable disease connections. Multiple ML models are presented for risk assessment and a comparison is carried out based on performance key performance indicators. The best-performing model for each disease was proved to be: the multi-layer perceptron for diabetes and heart disease, and extreme gradient boosting for cardiovascular disease. Comorbidities risk factor prediction and a XAI local model explanation is performed on significant case studies. In addition, XAI global model interpretation is given for the entire dataset providing insights on the features’ contribution to the models’ implementation. Moreover, the graph-based visualization of indirect disease co-occurrence is performed by filtering connections according to different relative risk factor thresholds. This interface can be exploited by healthcare professionals to obtain, according to the needs and the clinical approach, a global perspective on obesity and its associated pathologies prevention as well as long-term treatment and care provision
Fractional-Order Identification and Control of Heating Processes with Non-Continuous Materials
The paper presents a fractional order model of a heating process and a comparison of fractional and standard PI controllers in its closed loop system. Preliminarily, an enhanced fractional order model for the heating process on non-continuous materials has been identified through a fitting algorithm on experimental data. Experimentation has been carried out on a finite length beam filled with three non-continuous materials (air, styrofoam, metal buckshots) in order to identify a model in the frequency domain and to obtain a relationship between the fractional order of the heating process and the different materials’ properties. A comparison between the experimental model and the theoretical one has been performed, proving a significant enhancement of the fitting performances. Moreover the obtained modelling results confirm the fractional nature of the heating processes when diffusion occurs in non-continuous composite materials, and they show how the model’s fractional order can be used as a characteristic parameter for non-continuous materials with different composition and structure. Finally, three different kinds of controllers have been applied and compared in order to keep constant the beam temperature constant at a fixed length
Fractional-Order Identification and Control of Heating Processes with Non-Continuous Materials
Exercise-related changes in lower body regional muscle development .
This study had 2 primary aims (1) compare the effects of multi-joint vs. single-joint lower body exercise on regional muscular development of the quadriceps, and; (2) compare the effects of exercises performed at different knee-joint angles on hypertrophy of the triceps surae. Thirty young, resistance-trained participants unilaterally performed a combination of the following lower body exercises: leg press, leg extension, straight-leg toe press, and seated calf raise. The participants' right legs were randomly allocated to perform 1 of the following 4 conditions: (1) leg press and straight-leg toe press; (2) leg-press and seated calf raise; (3) leg extension and straight-leg toe press; (4) leg extension and seated calf raise. Based on the allocated condition, the contralateral leg performed the other 2 exercises included in the protocol. Training was carried out twice per week on non-consecutive days for 8 weeks. Point estimates for the rectus femoris outcomes favored the single-joint exercise intervention with posterior probabilities ranging from 0.910 ≤ p ≤ 0.990. In contrast, point estimates for the vastus lateralis outcomes favored the multi-joint exercise intervention with posterior probabilities ranging from 0.875 ≤ p ≤ 0.994. Regarding the triceps surae, the point estimate favored straight-leg plantar flexion for muscle thickness of the medial gastrocnemius (p = 0.991), with equivocal results observed for the lateral gastrocnemius and soleus. Our findings indicate that exercise selection can influence regional hypertrophy of the muscles of the lower limbs and evidence of differences can be measured within 8 weeks