Impedance Analysis Research Articles

Electrical performance of a novel extravascular temporary pacing lead system

Abstract Background An investigational extravascular (EV) cardiac temporary pacing system has been developed that includes a parasternally-positioned temporary pacing lead within the anterior mediastinum. The pacing lead is inserted using a custom delivery tool through a parasternal skin incision. This novel system may provide clinical advantages over existing device alternatives that require intravascular, endocardial, or epicardial contact. Objective The purpose of this study was to evaluate electrical performance of an EV temporary pacing lead over 48 hours. Methods In this single-center study, patients who underwent a transvenous (TV) permanent pacemaker implant or replacement were simultaneously implanted with the investigational EV temporary pacing lead. Electrical performance was evaluated through analysis of capture thresholds, impedance, and R-wave amplitudes during multiple times on the day of the procedure and on the subsequent 2 days of follow-up. Results Lead insertions with acute capture were successful in all 8 patients (40% female, 71 ± 8 years, BMI 27 ± 3 kg/m2). Mean acute measurements for pacing capture threshold at 1.5 ms, impedance and R-wave amplitude were 6.2 mA, 1396 Ω, 5.4 mV, respectively. Pacing capture was maintained in 100% of assessments conducted over 3 days (Figure 1). There were no serious complications during insertion, removal or chronic use of the lead. Conclusions Results support that the investigational EV temporary pacing lead is capable of safely providing temporary pacing with thresholds typically well below the maximum output of temporary pacemakers.

Development of an Open-Source Robotic NDT Solution for Automated Composite Repair Testing

Abstract Non-destructive testing (NDT) plays an important role in aircraft maintenance and repair processes, ensuring the structural integrity necessary for safe operation. The paper presents the design and evaluation of an animated, low-cost robotic NDT system tailored for inspecting composite bonding agents. The system integrates commercially available components, including a three-degree-of-freedom robotic arm and a Raspberry Pi 4B, managed by custom Python software with a user-friendly graphical interface. Mechanical Impedance Analysis (MIA) and Eddy Current Testing (ET) methods were employed to assess the system’s performance on representative test specimens. Results indicate that the system delivers reliable and accurate measurements comparable to commercial tools like the MAUS V, while offering simplicity and modularity. Limitations such as scanning speed and handling of complex geometries are acknowledged, with potential solutions proposed for future enhancement. The system provides an affordable and customizable alternative for NDT automation in the aerospace industry.

Standardization of transthoracic impedance values for estimating heart failure and its utility

Abstract Background The use of intrathoracic impedance for examining pleural effusion in heart failure patients has been explored previously. However, due to concerns about its accuracy and complexity, transthoracic impedance values have had limitations in quantifying extravascular lung water. Our dual objectives were to clarify the relationship between intrathoracic conditions and percutaneous transthoracic impedance values, and to establish a basic model for a new machine learning-based estimation system for assessing intrathoracic conditions in patients with heart failure. Methods First, we developed a live porcine congested lung model that induced pleural effusion by substantial fluid loading, and then longitudinally evaluated its correlation with percutaneous transthoracic impedance values. Second, we conducted multi-frequency bioelectrical impedance analysis to simultaneously collect electrical, physical, and hematological data from 63 hospitalized heart failure patients and 82 healthy volunteers Results In the porcine model, pleural effusion correlated with a concurrent decrease in SpO2 and a gradual decrease in impedance. We indexed and generated features from the measured values and developed an intrathoracic estimation model based on electrical measurements and clinical findings using a decision tree-based machine learning approach. Among the 286 features collected per individual, the model used 16 features. Notably, the model demonstrated high accuracy in discriminating patients with pleural effusion, achieving an AUC of 0.905 (95% CI: 0.870-0.940) in cross-validation, significantly outperforming the conventional frequency-based method. Conclusions Transthoracic impedance values, when indexed, reflect intrathoracic conditions and improve estimation. Our results highlighted the potential of machine learning and thoracic impedance measurement for accurate estimation of pleural effusion. This approach provides an effective means of assessing intrathoracic conditions. Figure: The upper figure shows the relationship between impedance values and pleural effusion in the congested lung model. On these results, human data were collected to construct the estimation model. The lower illustrates the accuracy of the model and provides a comprehensive view of the system.

Prognostic value of sarcopenia defined by the Sarcopenia Definitions and Outcomes Consortium criteria in patients with heart failure

Abstract Background Sarcopenia, the loss of skeletal muscle mass and function, is recognized as a negative prognostic factor in heart failure patients. Current guidelines, such as those by the Asian Working Group for Sarcopenia (AWGS), emphasize quantifying muscle mass using methods like bioelectrical impedance analysis or dual-energy X-ray absorptiometry, known for their precision. In contrast, the Sarcopenia Definitions and Outcomes Consortium (SDOC) focuses on functional parameters. However, its applicability and effectiveness as a prognostic indicator in heart failure remain uncertain. Purpose To determine the prognostic utility of sarcopenia determined by the SDOC diagnostic criteria in predicting all-cause mortality among older patients with heart failure, and to compare its prognostic predictability with that of the AWGS 2019 diagnostic algorithms. Methods This was a post-hoc analysis of the FRAGILE-HF study, a prospective, multicenter, observational study involving patients aged ≥65 years hospitalized for heart failure. Sarcopenia was diagnosed according to two definitions: AWGS 2019 guidelines criteria and the SDOC criteria, which diagnose sarcopenia based only on grip strength and gait speed. With SDOC criteria, patients were divided into three groups: sarcopenia (low grip strength and decreased gait speed), pre-sarcopenia (low grip strength or decreased gait speed), and non-sarcopenia (normal grip strength and normal gait speed) groups. Two logistic models for the primary outcome were constructed by adding the information on pre-sarcopenia and sarcopenia defined by AWGS 2019 and SDOC to the MAGGIC-HF risk score + log BNP, and prognostic predictability was compared by receiver operating characteristic curve areas under the curve (ROC-AUC) and net-reclassification improvement (NRI) between three models. The primary outcome was 2-year mortality. Results Of 1282 study patients, pre-sarcopenia and sarcopenia were diagnosed in 357 and 786 individuals, respectively, according to SDOC criteria. The Kaplan-Meier analysis revealed a significant stepwise association between the sarcopenic status and the primary outcome. The adjusted Cox proportional hazards analysis indicated a significant stepwise association between sarcopenic status and mortality risk (pre-sarcopenia, hazard ratio [HR]: 1.22, 95% confidence interval [CI]: 0.66–2.28, P= 0.525; sarcopenia, HR: 1.89, 95% CI: 1.08–3.34, P= 0.027). No significant difference was observed in the prognostic capabilities between the two models adding sarcopenia defined by SDOC and AWGS 2019 diagnostic criteria to the model incorporating the MAGGIC-HF risk score + log BNP (NRI: -0.009, 95% CI: -0.193–0.174, P=0.920, with ROC-AUC of 0.697 for SDOC and 0.703 for AWGS 2019, P=0.675, respectively). Conclusion Diagnosing sarcopenia with the SDOC criteria, which does not include muscle mass, provides incremental prognostic information as same as that defined by AWGS 2019 criteria.Figure

Pulmonary hypertension in patients on chronic hemodialysis

Abstract Introduction Pulmonary hypertension (PH) is a common condition in patients with advanced chronic kidney disease and is associated with higher morbidity and mortality. High arteriovenous fistula (AVF) flow is one of known etiological factors, but the association of AVF flow within the acceptable range and PH has not been tested. Moreover, the prevalence of PH differed among various studies. Purpose The aims of this study were: 1. to describe the prevalence of PH in the Czech hemodialysis population; 2. to analyze the relation between dialysis fistula flow and PH; 3. to reveal other etiology of PH in a cross-sectional non-invasive trial. Methods We analyzed index visits of the cohort CZecking HF-CKD study (ISRCTN 18275480). Thus, this is a cross-sectional analysis based on detailed echocardiography with cardiac output (CO) calculation, evaluation of the central venous pressure (CVP) and AVF flow, bio-impedance and basic laboratory tests. All these measurements were done within an hour. The presence of PH was based on the peak systolic pulmonary arterial pressure (PASP) estimation above 35 mmHg. Results We analyzed data of 162 patients. They were 73,2 ± 12,6 years old, dialysis vintage 30 ± 69 months. Pulmonary hypertension was present in 35 % of analyzed patients. Among these patients, mild PH was present in 35 %, moderate in 53 % and severe in 12 %. There was no significant impact of AVF/AVG flow on the presence of PH or PASP value (Table 1.). However patients with PH had higher prevalence of heart failure (HF), which was present in 86 % of patients with PH and only in 46 % without PH (p<0.00001), see Figure 1. This and other differences presented in Table 1. document significant contribution of postcapillary PH. Patients with PH were also more overhydrated when considered by CVP, by overhydration measurement using bioelectrical impedance analysis and had higher N-terminal pro brain natriuretic peptide (NTproBNP) (Table 1.). There was a positive correlation between systemic vascular resistance (SVR) and PASP (R=0,333, p= .001). Conclusions PH is present in approximately one third of the dialysis patients. The presence of heart failure and changes of left heart chambers show for the postcapillary etiology of PH. Neither the prevalence nor the severity of PH were significantly related to arteriovenous access flow.

New nomenclature and subclassification of steatotic liver disease and loss of skeletal muscle mass: A longitudinal cohort study.

Identifying risk factors for sarcopenia is important due to its significant effect on health. The association between sarcopenia and the newly proposed steatotic liver disease (SLD) and its subclassification has largely been unexplored. This longitudinal cohort study included 67905 adults who underwent at least two health checkup examinations. SLD participants were categorized as cryptogenic SLD, metabolic dysfunction-associated SLD, metabolic dysfunction-associated alcoholic liver disease, or alcoholic liver disease. Appendicular skeletal muscle mass (ASM) was evaluated by bioelectrical impedance analysis. The average duration of follow-up was 5.9years. The annual ASM change was -31.0g (95% CI -32.3, -29.6) and -38.3g (-40.3, -36.3) in participants without and with SLD, respectively. When assessed based on SLD severity, annual ASM loss was fastest in SLD participants with Fibrosis-4 score ≥1.3, followed by those with Fibrosis-4 score <1.3 and those without SLD. In multivariable adjusted analysis, annual ASM loss was fastest in participants with metabolic dysfunction-associated alcoholic liver disease (-49.8g; -93.1, -6.5), followed by those with metabolic dysfunction-associated SLD (-24.7g; -60.4, 11.1), and alcoholic liver disease (-24.4g; -91.1, 42.3), and slowest in those with cryptogenic SLD (reference). This pattern was more pronounced in participants with Fibrosis-4 score ≥1.3. The loss of skeletal muscle mass was fastest in the participants with metabolic dysfunction-associated alcoholic liver disease, followed by participants with metabolic dysfunction-associated SLD, alcoholic liver disease, and cryptogenic SLD. Particular attention to prevent sarcopenia should be given to SLD patients with cardiometabolic risk factors or alcohol consumption, especially in patients with advanced fibrosis.

Evaluating Muscle Mass Changes in Critically Ill Patients: Rehabilitation Outcomes Measured by Ultrasound and Bioelectrical Impedance

Background/Objectives: The loss of muscle mass is common in critically ill patients and is associated with poor prognosis, and efforts have been made to mitigate muscle loss through rehabilitation. This study aimed to evaluate changes in muscle mass in critically ill patients following rehabilitation. Methods: We enrolled 53 patients expected to stay in the ICU for more than 7 days, dividing them into rehabilitation (15 patients) and no rehabilitation groups (38 patients). Muscle mass was measured using ultrasound and bioelectrical impedance analysis (BIA). Results: Baseline characteristics and comorbidities showed no statistical differences between the two groups. Initial measurements of muscles showed no significant differences between the groups in rectus femoris thickness, total anterior thigh muscle thickness, cross-sectional area, echogenicity, or in-body skeletal muscle mass at baseline and 7 days. However, at 14 days, significant differences emerged. The rehabilitation group had greater rectus femoris thickness (1.42 cm vs. 0.81 cm, p = 0.007) and total anterior thigh muscle thickness (3.79 cm vs. 2.32 cm, p = 0.007) compared to the no rehabilitation group. Additionally, the rehabilitation group experienced a significantly smaller reduction in rectus femoris cross-sectional area (−4.6% vs. −22.8%, p = 0.021). Although survival rates were higher in the rehabilitation group (73.3% vs. 52.6%), this difference was not statistically significant (p = 0.096). Conclusions: Our findings suggest that rehabilitation in critically ill patients is associated with a slower rate of muscle loss, particularly in the cross-sectional area of the rectus femoris muscle, which may be beneficial for patient recovery.

Association of age to nutritional status and muscle mass in children with transfusion-dependent β-thalassemia: a cross-sectional study

BackgroundTransfusion-dependent β-thalassemia (TDT) is a hereditary blood disorder that often leads to complications affecting growth, nutritional status, and muscle mass in children. This study aims to investigate the associations between age, nutritional status, and muscle mass in children with TDT, providing insights into the progressive impact of age on these parameters.MethodsOne hundred twenty-two children with TDT from March 2023 to March 2024 were enrolled in this cross-sectional study. Their nutritional status was assessed using the 2006–2007 World Health Organization (WHO) Growth Charts, and their muscle mass was measured using bioelectrical impedance analysis (BIA). Data related to age, gender, weight, height, fat-free mass (FFM), skeletal muscle mass (SMM), and soft lean mass (SLM) of children were collected for comparative analysis from the hospital record room. Furthermore, Spearman’s rank correlation coefficients and regression analyses were utilized to investigate the associations between age and both nutritional status and muscle mass.ResultsThe results of this study revealed negative correlations between age and wasting (r = −0.26, p &amp;lt; 0.001), stunting (r = −0.28, p &amp;lt; 0.001), FFM (r = −0.3, p &amp;lt; 0.001), SMM (r = −0.23, p &amp;lt; 0.01), and SLM (r = −0.36, p &amp;lt; 0.001). The regression analysis indicated that age was an independent predictor of wasting, stunting, and reduced muscle mass in these children (all p &amp;lt; 0.001).ConclusionOur study observed a trend of worsening stunting, wasting, and muscle loss in children with TDT as they age. These findings highlight the importance of monitoring both nutritional and muscular health in TDT patients. Early detection and comprehensive nutritional management may improve outcomes in this population.

Anthropometric indices in older adults with and without Locomotive Syndrome

BackgroundLocomotive syndrome is a major challenge for older adults, and anthropometric indices can greatly affect the musculoskeletal system. This study aimed to compare the anthropometric indices between older adults with and without locomotive syndrome.MethodsThis descriptive-analytical study was performed on 211 older adults using random cluster sampling from a population of over-60 individuals covered by comprehensive health service centers in Sari in Autumn, 2021. Participants were divided into two groups: with and without locomotive syndrome. Locomotive syndrome was assessed via the 25-item Geriatric Locomotive Function Scale questionnaire, and the level of anthropometric indices was determined through the Bioelectrical Impedance Analysis device. Data were analyzed by independent t-test, Mann-Whitney U, Chi-Square, and Binary logistic regression in SPSS, Version 23 (P < 0.05).ResultsThe average age of older adult participants was 78.4 ± 6.6 years. In older adults with locomotive syndrome, the average percentage of fat-free mass (P < 0.001) was significantly lower while the average percentage of fat mass and fat mass index (P < 0.001) was significantly higher. Older adults with locomotive syndrome were shorter in height (P < 0.001) and had a higher body mass index (P < 0.05). Fat-free mass percentage (OR = 0.59) and body mass index (OR = 1.4) predicted the incidence of locomotive syndrome in the subjects. Significant differences such as chronic diseases, chronic pain, falls, age, and gender were observed between the two groups (P < 0.05).ConclusionAnthropometric indices can play an important role in the occurrence of locomotive syndrome in older adults. Evaluation of anthropometric indices and management of body composition can help prevent locomotive syndrome and improve the quality of life of older adults.

The addition of Bi2WO6 nanoparticles to polyvinyl alcohol film: Improvements in optical, mechanical, and electrical properties

This study deals with the influence of adding Bi2WO6 (BWO) nanoparticles on the optical, structural, dielectric, and mechanical properties of polyvinyl alcohol (PVA). BWO nanoparticles synthesized by solvothermal method were characterized by X-Ray diffraction (XRD) and scanning electron microscope (SEM-EDS). The thick film nanocomposites were analyzed by Fourier Transformed Infrared (FTIR) spectrometer, XRD device, SEM, atomic force microscope (AFM), ultraviolet visible (UV–Vis) spectrophotometer, impedance analyzer, and tensile test machine. While FTIR analyses confirmed the formation of composite structure and the presence of BWO in the composites, AFM views indicated the reduced roughness for composites. Additionally, the UV–Vis light absorption spectra revealed a narrowed band gap in the composites. Moreover, with increasing BWO contribution, gradual increases were recorded in Young's modulus, toughness and % breaking strain parameters. The frequency dependent dielectric properties was also shown that the energy storage ability of the PVA matrix enhances 25 % and 50 % due to 2 % and 3 % BWO additives, respectively. However, the composite with higher ε′ and lower ε″ values than the pure PVA in the entire frequency range was the 2 % BWO-doped nanocomposite. Based on the serious and simultaneously improvements in electrical, optical and mechanical properties, it can be suggested that 2 % BWO additive provides the opportunity to expand the application area of PVA synergistically.

Droplet Impedance Feedback-Enabled Microsampling Microfluidic Device for Precise Chemical Information Monitoring.

Microelectrodes have transformed our understanding of spatiotemporal responses to electrical stimulation. However, biological signals are often molecular, complicating the capture of intricate chemical signals. The microfluidic chip developed in this paper accurately measures droplet volume by using impedance analysis. The utilization of droplet volume as a feedback signal for precise microsampling pressure control ensures that microsampling remains unaffected by droplet volume influence. Once the microsampling is complete, chemiluminescence detection enables high temporal resolution and continuous and sensitive monitoring of chemical information within the droplets. Experimental verification shows that the chip can avoid volume influence through impedance feedback, achieving consistent and stable microampling at the nanoliter level (0-3 nL). In just 0.3 s, it can perform sensitive chemiluminescence detection of H2O2 and glucose within droplets. The linear detection ranges for these analytes are 10-50,000 and 20-600 μM, respectively, with the limit of detection being 0.648 and 0.334 μM. The significance of this chip lies in its ability to reveal changes in both electrical and chemical signals during transient biological processes. Its potential applications are numerous, encompassing a wide range of emerging areas such as single-cell analysis, cell communication, and cellular immunity.

Habitual water intake impacted the body composition of young male athletes in free-living conditions: a cross-sectional study

The study aimed to explore the associations between water intake and body composition and differences of body composition in different water itake and hydration statuses among young male athletes. A cross-sectional study was conducted among 111 young male athletes in Beijing, China. Total drinking fluids (TDF) and water from food were assessed using a 7-day, 24-h fluid intake record questionnaire and the duplicate portion method, respectively. The osmolality of 24-hour urine and blood samples was tested. Body composition was measured using a bioelectrical impedance analyzer twice at 5-min intervals. Participants were divided into two groups based on the recommendations of total water intake (TWI) and TDF in China, as well as into three groups based on 24-h urine osmolality. Pearson's correlation coefficients were calculated to determine the relationship between water intake and body composition. Chi-square tests and Student's t-tests were used to compare differences. A total of 109 participants completed the study. TDF (r = 0.230, p = 0.016; r = 0.234, p = 0.014; r = 0.242, p = 0.011) and TWI (r = 0.275, p = 0.004; r = 0.243, p = 0.011; r = 0.243, p = 0.011) were positively correlated with total body water (TBW), intracellular water (ICW), and extracellular water (ECW). TBW/body weight (BW) was positively associated with TDF percentage of BW (TDF/BW) (r = 0.267, p = 0.005), water from food percentage of BW (r = 0.217, p = 0.024), and TWI percentage of BW (TWI/BW) (r = 0.316, p = 0.001). Participants who met the TDF recommendation of China had 1.3 kg higher skeletal muscle mass (SMM), 0.9 kg higher ICW, and 0.5% higher TBW/BW than those who did not (all p &amp;lt; 0.05), with fat-free mass (FFM) and TBW being higher (p = 0.051; p = 0.050). Those who met the TWI recommendation of China had 1.3 kg higher SMM, 2.4 kg higher FFM, 1.1 kg higher ICW, 0.6 kg higher ECW, and 1.7 kg higher TBW than their counterparts (all p &amp;lt; 0.05). Moderate associations were found between water intake and body composition. No significant differences were observed among participants in three hydration statuses (all p &amp;gt; 0.05). Participants who met the TWI or TDF recommendations had better body composition distribution than their counterparts. Thus, habitual water intake, not hydration status, affects body composition among athletes in free-living conditions.

Synthesis, Structural, Morphology and Magnetic Properties: Effect of La on Multiferroic Nature of BiFeO3 Nanoparticles

Objectives: The present study focuses on developing La-doped BiFeO3 multiferroic materials for dielectric absorber applications. Methods: The samples are characterized by X-ray Diffractometer (XRD). Further, the morphology is examined using field emission electron microscopy (FESEM) and Transmission Electron Microscopy (TEM). The dielectric parameters and ac-electrical parameters are carried out by impedance spectroscopy. The magnetic properties are studied using a vibrating sample magnetometer VSM, P-E loop. Findings: XRD confirms the rhombohedral (trigonal) structure of BLFO nanoparticles. The grain and particle size values are determined by SEM and TEM, respectively. The dielectric and ac-electrical parameters for all the samples are thoroughly discussed at room temperature. The Maxwell-Wagner or interfacial polarization is noticed at low input field frequencies for x=0.2-0.8. The impedance analysis shows the contribution of grain and its boundary in the electrical conduction mechanism. The multiferroic behavior is examined using M-H loops, P-E loops, and μi-f plots. Novelty: The samples are synthesized by the hydrothermal process to prepare La-doped BiFeO3 nanomaterials. Keywords: Nanoparticles, Electron Microscopy, Multiferroic, Magnetization, Polarization, Permeability

Elucidating the Performance Limitations of a 25 cm2 Pure‐Water‐Fed Non‐Precious Metal Anion Exchange Membrane Electrolyzer Cell

AbstractAnion exchange membrane (AEM) water electrolysis has emerged as a promising technology for producing hydrogen in a carbon‐neutral economy. To advance its industrial application, performance evaluations of non‐precious metal AEM electrolyzers with electrode areas of 25 cm2 were conducted. The focus was on pure water operation, achieving a current density of 0.26 A cm−2 at a voltage of 2.2 V. To gain a better understanding, the AEM electrolyzer was also operated in aqueous KOH, yielding 1.2 A cm−2 at 2.2 V. By adding a liquid electrolyte and by varying cell components, causes of the occurring performance limitations and ways to improve the AEM electrolyzer were identified. Electrochemical impedance analysis showed that the activation loss at the anode due to sluggish OER kinetics was the limiting factor at low current densities. At higher current densities, which is the operating range of interest for industrial application, the ohmic resistance from the membrane was the dominant factor limiting high performance in pure water operation.

Somatotype and body composition profiles of children and adolescent male basketball players.

Somatotype and body composition (BC) are related to athletes' physical fitness and performance. The aims of this study were (a) to determine the somatotype and BC profiles of children and adolescent male basketball players and (b) to investigate the relationship between somatotype and BC. Four hundred forty-nine children and adolescent male basketball players between the ages of 7-17 participated in the study voluntarily. Somatotype scores were determined according to the Heath & Carter method, and BC was evaluated by the bioelectrical impedance analysis (BIA) method. Pearson correlation test was used to determine the relationship between somatotype and BC. A significant positive relationship between body mass (BM), body fat (BF), body mass index (BMI), and fat mass (FM) with endomorphy and mesomorphy scores; a significant negative relationship between body height (BH) with endomorphy and mesomorphy scores were found. In addition, ectomorphy scores were significantly positively correlated with BH and negative with other parameters. This current research shows that as age increases, BH, BM, BMI, and FM increase, and BF, endomorphy, and mesomorphy scores decrease. With increasing age, the somatotype score changes from endomorphic mesomorphy (5-7-2) to balanced mesomorphy (3-6-3). The comprehensive data presented in this study can serve as a reference value and be used as an indicator for children and adolescent basketball coaches.

Anthropometric Profile and Position-Specific Changes in Segmental Body Composition of Professional Football Players Throughout a Training Period.

Body and anthropometric profiles of football players vary depending on the physiological and technical demands imposed by different positions. The aim of this study was to evaluate the body composition of professional soccer players in relation to their position on the field during a training macrocycle. The Direct Segmental Multi-Frequency Bioelectrical Impedance Analysis method was used to analyze 58 players at six key moments of the macrocycle. The results show that body profiles are adjusted to the specific demands of each position. Midfielders showed the lowest muscle mass, while defenders showed many notable changes. In general, as the season progressed, all field players experienced an increase in trunk body fat. Fat and lean mass values of goalkeepers differed greatly from the rest. The greatest variations in body composition were observed during pre-season and transition in relation to variations in training load and competitive intensity. The results suggest that the phase of the macrocycle has a greater influence on these variations, although the physical characteristics of each position are relevant. Understanding these dynamics allows for the design of more personalized and efficient training programs to optimize the performance of footballers according to their roles and each stage of the season.

Weight loss, changes in body composition and inflammatory status after a very low-energy ketogenic therapy (VLEKT): does gender matter?

BackgroundConsidering differences in body composition and inflammatory status between sexes, as well as recent recommendations advocating for personalized dietary approaches, this study aimed to explore how sex influences weight loss, changes in body composition, and inflammatory status in subjects with grade I and II obesity undergoing a 45-day of the Very Low-Energy Ketogenic Therapy (VLEKT).MethodsParticipants (21 premenopausal females and 21 males), included in the study adhered to the 45-day of the VLEKT and underwent assessments of anthropometric parameters (weight, height, body mass index—BMI –, and waist circumference), body composition via bioelectrical impedance analysis, and inflammatory status measured by high sensitivity C-reactive protein (hs-CRP) levels at baseline and post-intervention.ResultsAt baseline, premenopausal females and males did not differ in BMI (p = 0.100) and hs-CRP levels (p = 0.948). Males demonstrated overall larger benefits than premenopausal females from the VLEKT in terms of weight loss (Δ% = − 11.63 ± 1.76 vs − 8.95 ± 1.65 kg, p < 0.001), fat mass (Δ% = − 30.84 ± 12.00 vs -21.36 ± 4.65 kg, p = 0.002), and hs-CRP levels (Δ% = − 41.42 ± 21.35 vs − 22.38 ± 17.30 mg/L, p = 0.003). Of interest, in males phase angle values are statistically improved compared to female (Δ% = 17.11 ± 9.00 vs 7.05 ± 3.30°, p < 0.001).ConclusionThese findings underscore the importance of considering sex-specific responses in personalized obesity treatment strategies, particularly dietary interventions like VLEKTs.Graphical

Improved functional oral intake and exercise training attenuate decline in aerobic capacity following chemoradiotherapy in patients with esophageal cancer.

To investigate the impact of chemoradiotherapy on the physical fitness of patients with oesophageal cancer, and the clinical factors influencing it. A total of 67 participants successfully completed the study, with 18 of them engaging in supervised, in-hospital aerobic training at moderate intensity for a minimum of 20 sessions. Cardiopulmonary exercise testing, hand grip strength, body composition assessed via bioelectrical impedance analysis, patient-generated subjective global assessment, albumin, and the Functional Oral Intake Scale (FOIS) were evaluated before chemoradiotherapy and 6-8 weeks after its completion. Among the participants, cardiopulmonary fitness, hand grip strength, and phase angle of BC-BIA declined during chemoradiotherapy. Before and after chemoradiotherapy, V̇O2peak was 19.6 ± 4.4 and 17.4 ± 3.9 mL/min/kg respectively. The improvement in FOIS during chemoradiotherapy showed a positive correlation with changes in aerobic capacity. Additionally, exercise training was associated with attenuating the decline in aerobic capacity. Physical fitness deteriorated in patients with oesophageal cancer following chemoradiotherapy. Improvement in dysphagia helps maintain aerobic capacity. Additionally, exercise training has the potential to mitigate the decline. This discovery can serve as a reference for enhancing holistic care for patients with oesophageal cancer.

Frequency experimental identification approach for single-phase induction motor common-mode parameters

Introduction. The presence of broad-spectrum and high-amplitude electromagnetic interference (EMI) within a single-phase induction motor (SPIM) drive poses a significant threat to both the system and other electronic equipment. High-frequency (HF) models of electrical motors play a critical role in overcoming these challenges, as they are essential for characterizing electromagnetic compatibility (EMC) in drives and designing effective EMI filters. The novelty of this study proposes an enhanced HF motor model based on transfer functions (TFs) to accurately represent the motor’s behavior at HFs for frequency-domain analyses in the range of 100 Hz to 30 MHz. Purpose. The equivalent HF model for a SPIM is discussed in this paper. The suggested equivalent circuit describes a motor’s common-mode (CM) properties. Methodology. HF model was developed by a frequency-domain analysis utilizing an experimental setup and MATLAB software. The motor impedance analysis is based on the measurement of variations in motor characteristics as a function of frequency in the CM setup. Originality. TF has been tuned using an asymptotic identification method of Bode to match the behavior of the real impedances of the motor parameters as a function of the frequency in the CM configuration. This tuned TFs are then synthesized into a comprehensive wideband EMC equivalent circuit model using the Foster network technique, which can be then simulated in any Spice-based simulator tools. Results. The proposed mathematical model was employed to conduct simulations, and the resulting predictions were validated against experimental data. CM response of the EMC equivalent circuit at low, medium, and HFs were compared between simulations and experimental measurements using Lt-Spice simulator software. Practical value. It is observed that results show satisfactory agreement with the measurements over a large frequency bandwidth [100 Hz–30 MHz], and the equivalent model of SPIM can be cascaded with other electronic and electrical modules to form a complete single-phase electric drive system model for fast analysis and prediction of system level EMI and electromagnetic sensitivity. References 37, table 5, figures 13.

Is body composition important in the context of renal function in pediatric neurogenic bladder?

Neurogenic bladder due to myelomeningocele (MMC) is a significant risk factor for chronic kidney disease in children. Cystatin C (CysC) is a more accurate GFR marker than creatinine as it is unaffected by muscle mass but may be influenced by fat mass and BMI. This study evaluates: (1) GFR measurement accuracy using CysC and creatinine in MMC-related neurogenic bladder, (2) the relationship between body composition via bioelectrical impedance analysis (BIA) and renal parameters, and (3) the use of BIA for non-invasive GFR and body composition assessment. Forty children (median age 9.96years) underwent serum creatinine, CysC testing, and BIA measurements. We assessed age, sex, spinal lesion level, anthropometric measurements, BMI, and activity using Hoffer's scale. GFR was calculated using five creatinine-based formulas, three CysC-based, and three combining CysC and creatinine, including BIA GFR as an alternative approach. Creatinine-based GFR estimates were significantly higher than CysC-based GFR. Although only 30% of MMC patients met the traditional BMI criteria for overweight/obesity, 62.5% were obese based on BIA-measured body fat percentage. Significant differences were found in CysC and CysC-based GFR equations within BMI and fat mass groups. Positive correlations were observed between CysC and body weight, BMI percentiles, body fat mass and fat-to-muscle ratio. Muscle mass positively correlated with creatinine. BIA-determined fat mass percentage is a more sensitive obesity indicator than BMI in MMC patients. CysC levels and CysC-based GFR equations are influenced by body fat mass, requiring consideration of adiposity to avoid misestimating renal impairment.