Impedance Analysis Data Research Articles

Impedance Spectroscopy and Study of Electrical Properties of Pb(Zr<sub>0.52</sub>Ti<sub>0.48</sub>)<sub>1-x</sub>Fe<sub>x</sub>O<sub>3-x</sub> (0≤x≤0.20) Ceramics

Iron substituted Lead zirconate titanate nanoparticles Pb (Zr0.52Ti0.48) 1-x FexO3-x (PZTFx) (for (x=0.00, 0.025, 0.05, 0.075, 0.10, 0.15 and 0.20) was prepared using the sol-gel route in the morphotropic phase boundary (MPB) region. The X-ray diffraction data revealed the formation of both rhombohedral and tetragonal structures. The microstructural properties of the compounds were examined through the scanning electron microscopy (SEM) technique. The impedance spectroscopy and conductivity spectroscopy were carried out over a wide range of temperatures (RT–400°C) and frequencies (100 Hz–2 MHz) to investigate the grain and grain boundary effect on the electrical properties of PZTFx. The complex impedance analysis data have been presented in the Nyquist plot which is used to identify the corresponding equivalent circuit and fundamental circuit parameters. Cole– Cole plots indicate Debye-type dielectric relaxation and the grain boundaries resistance is dominant at room temperature. The Nyquist plot showed the negative temperature coefficient of resistance (NTCR) character of PZTFx ceramics. The dielectric properties of (PZTFx) ceramics as a function of temperature are studied and displayed a resonance phenomenon for all samples. Temperature-dependent conductivity behavior indicated an Arrhenius type of thermally activated process in the low-temperature region. Activation energy has been calculated from the temperature-dependent DC electrical conductivity measurements for all the samples.

Machine learning-based obesity classification considering 3D body scanner measurements

Obesity can cause various diseases and is a serious health concern. BMI, which is currently the popular measure for judging obesity, does not accurately classify obesity; it reflects the height and weight but ignores the characteristics of an individual’s body type. In order to overcome the limitations of classifying obesity using BMI, we considered 3-dimensional (3D) measurements of the human body. The scope of our study was limited to Korean subjects. In order to expand 3D body scan data clinically, 3D body scans, Dual-energy X-ray absorptiometry, and Bioelectrical Impedance Analysis data was collected pairwise for 160 Korean subjects. A machine learning-based obesity classification framework using 3D body scan data was designed, validated through Accuracy, Recall, Precision, and F1 score, and compared with BMI and BIA. In a test dataset of 40 people, BMI had the following values: Accuracy: 0.529, Recall: 0.472, Precision: 0.458, and F1 score: 0.462, while BIA had the following values: Accuracy: 0.752, Recall: 0.742, Precision: 0.751, and F1 score: 0.739. Our proposed model had the following values: Accuracy: 0.800, Recall: 0.767, Precision: 0.842, and F1 score: 0.792. Thus, our accuracy was higher than BMI as well as BIA. Our model can be used for obesity management through 3D body scans.

The role of muscle ultrasound to predict sarcopenia

ObjectivesThis study aimed to provide data about the role of muscle ultrasound (US) to predict sarcopenia. MethodsA total of 313 geriatric outpatients (age ≥65 y) were enrolled in the study. After a comprehensive geriatric assessment, anthropometric measurement and handgrip strength (HGS) data were obtained and a bioelectrical impedance analysis was performed. Sarcopenia was diagnosed using HGS and bioelectrical impedance analysis data. Gastrocnemius medialis (GC), rectus femoris (RF), and rectus abdominis (RA) muscle thickness as well as the RF cross-sectional area (CSA) were measured with US. The role of muscle US to predict sarcopenia was defined with a receiver operating characteristics analysis. ResultsThe prevalence of probable and confirmed sarcopenia were 43.8% (n = 137) and 13.4% (n = 42), respectively. All muscle US parameters had positive correlations with both HGS and the fat-free mass index. There were inverse correlations between all muscle US parameters and the five-item sarcopenia questionnaire. The RF CSA had stronger correlations with the five-item sarcopenia questionnaire, HGS, and the fat-free mass index than others. The values of GC, RF, and RA muscle thickness and the RF CSA to predict sarcopenia for women/men were 13.9/13.8 mm (area under the curve [AUC]: 0.817/0.707 mm), 13/15.5 mm (AUC: 0.760/0.736 mm), 4.3/5.2 cm2 (AUC: 0.766/0.773 cm2), and 6.6/7.0 mm (AUC: 0.740/0.688 mm), respectively. ConclusionsGC, RF, and RA muscle thickness and the RF CSA all may predict sarcopenia accurately in geriatric outpatients.

Comparison of lateralized bioelectrical impedance analysis data and lateralized manual muscle testing score in amyotrophic lateral sclerosis (als) during the initial and final nutritional assessment

Rationale: Amyotrophic lateral sclerosis (ALS) is a rare disease with a poor prognosis. During follow-up, manual muscle testing (MMT) makes it possible to determine the laterality of the functional impairment. Bioelectrical impedance analysis (BIA) determines the body composition and therefore the fat-free mass (FFM), reflecting muscle mass. The BIA can be lateralized by right or left hemi-body. The objectives of this work were to determine if there was a link between the lateralized changes in body composition in BIA and the lateralized motor deficit objectified by MMT, and to determine if this link was stable during the course of the disease.

Application of Electroimpedance Spirometry for Clinical Assessment of Respiratory Function Indices

A practical method of studying the dynamics of respiratory function associated with the registration of the electrical impedance of conductive biological fluids exhaled by the patient is described. In the model measuring cell, the physical causes and relationships in the conductivity of the air flow, saturated with an electrolytic fluid aerosol created by an ultrasonic nebulizer have been investigated experimentally. The design of a new electrical impedance spirometer in the form of a mouthpiece with electrical sensors, filled with a porous medium impregnated with electrolyte, through which the patient breathes, is developed and tested. To register fluctuations in the magnitude of the impedance modulus, an original hardware and software complex is used, made on the basis of a high-speed analog-to-digital converter. Based on electrical impedance analysis data, the methods are proposed for quantitative assessment of the basic spirometric medical indicators characterizing the state and functioning of the patient’s breathing apparatus, such as respiration rate, entry and expiration rate, exhaled air volume, amount and concentration of exhaled lung fluid.

NutriCatt Protocol Improves Body Composition and Clinical Outcomes in Elderly Patients Undergoing Colorectal Surgery in ERAS Program: A Retrospective Cohort Study.

Background: A poor body composition, often found in elderly patients, negatively impacts perioperative outcomes. We evaluated the effect of a perioperative nutritional protocol (NutriCatt) on body composition and clinical outcomes in a cohort of elderly patients undergoing colorectal surgery in a high-volume center adopting the ERAS program. Methods: 302 out of 332 elderly (>75 years) patients from 2015 to 2020 were identified. Patients were divided according to their adherence, into “NutriCatt + ERAS” (n = 166) or “standard ERAS” patients (n = 136). Anthropometric and bioelectrical impedance analysis data were evaluated for NutriCatt + ERAS patients. Complications, length of hospital stay (LOS), and other postoperative outcomes were compared between both groups. Results: In NutriCatt + ERAS patients, significant improvements of phase angle (pre-admission vs. admission 4.61 ± 0.79 vs. 4.84 ± 0.85; p = 0.001; pre-admission vs. discharge 4.61 ± 0.79 vs. 5.85 ± 0.73; p = 0.0002) and body cell mass (pre-admission vs. admission 22.4 ± 5.6 vs. 23.2 ± 5.7; p = 0.03; pre-admission vs. discharge 22.4 ± 5.6 vs. 23.1 ± 5.8; p = 0.02) were shown. NutriCatt + ERAS patients reported reduced LOS (p = 0.03) and severe complications (p = 0.03) compared to standard ERAS patients. A regression analysis confirmed the protective effect of the NutriCatt protocol on severe complications (OR 0.10, 95% CI 0.01–0.56; p = 0.009). Conclusions: The NutriCatt protocol improves clinical outcomes in elderly patients and should be recommended in ERAS colorectal surgery.

Application of Artificial Neural Network to Somatotype Determination

Somatotype characteristics are important for the selection of sporting activities, as well as and the prevalence of several chronic diseases. Nowadays the most common method of somatotyping is the Heath–Carter method, which calculates the somatotype base on 10 anthropometric parameters. Another possibility for evaluation of somatotype gives commonly used bioelectrical impedance analysis), but the accuracy of the proposed formulas is questioned. Therefore, we aimed to investigate the possibility of applying an artificial neural network to achieve the formulas, which allow us to determine the endomorphy and mesomorphy using data on body height and weight and raw bioelectrical impedance analysis data in young women. The endomorphy (Endo), ectomorphy (Ecto), and mesomorphy (Meso) ratings were determined using artificial neural networks and the Heath–Carter method. To identify critical parameters and their degree of impact on the artificial neural network outputs, a sensitivity analysis was performed. The multi-layer perceptron MLP 4-4-1 (input: body mass index (BMI), reactance, resistance, and resting metabolic rate) for the Endo somatotype was proposed (root mean squared error (RMSE) = 0.66, χ2 = 0.66). The MLP 4-4-1 (input: BMI, fat-free mass, resistance, and total body water) for the Meso somatotype was proposed (RMSE = 0.76, χ2 = 0.87). All somatotypes (Endo, Meso and Ecto) can be calculated using MLP 2-4-3 (input: BMI and resistance) with accuracy RMSE = 0.67 and χ2 = 0.51. The bioelectrical impedance analysis and Heath–Carter method compliance was evaluated with the statistical algorithm proposed by Bland and Altman. The artificial neural network-based formulas allow us to determine the endomorphy and mesomorphy in young women’s ratings with high accuracy and agreement with the Heath–Carter method. The results of our study indicate the successful application of artificial neural network-based model in predicting the somatotype of young women. The artificial neural network model can be practically used in bioelectrical impedance analysis devices in the future.

Weight loss, phase angle, and survival in cancer patients undergoing radiotherapy: a prospective study with 10-year follow-up.

Cancer patients undergoing radiotherapy (RT) frequently experience weight loss and changes in body composition, which negatively affect their nutritional status, lead to a poor clinical prognosis, and reduce survival rates. This study aimed to evaluate whether changes in body weight, phase angle, and standardized phase angle are associated with longer survival in cancer patients undergoing RT. This prospective cohort study included 62 cancer patients who underwent RT between 2008 and 2009 and were followed until 2019. Anthropometric and bioelectrical impedance analysis data were assessed before and after RT. The Kaplan-Meier method was used to calculate survival, and mortality risk was assessed using the Cox proportional hazards model. Kaplan-Meier analysis indicated no significant difference in survival time after the 10-year follow-up between patients who had weight loss during RT and those with weight maintenance or weight gain during RT. Mortality risk was associated, in the adjusted multivariate analysis, with age (p = 0.023), site of treatment (p = 0.001), and weight loss during RT (p = 0.044). Every 1 kg lost increased the risk of death by 25% compared with patients who maintained or gained weight during RT. Changes in phase angle and standardized phase angle after RT were not associated with increased mortality risk. Weight loss during RT, site of treatment, and age are associated with a higher risk of death in cancer patients after the 10-year follow-up.

Simple estimation of excess fluid volume in hemodialysis patients based on multifrequency bioelectrical impedance analysis data

Simple estimation of excess fluid volume in hemodialysis patients based on multifrequency bioelectrical impedance analysis data

Structural, microstructural and dielectric properties of Ba1−xLaxTi(1−x∕4)O3 prepared by sol gel method

Detailed structural and dielectric properties of Lanthanum-doped barium titanate [Formula: see text]Lax[Formula: see text]O3 ceramic powders BLTx (where [Formula: see text]; 0.10; 0.20; 0.30 and 0.40)/BT, BLT10, BLT20, BLT30 and BLT40, synthesized by the sol gel process, calcined at 900∘C for 3[Formula: see text]h and sintered at 1250∘C for 6[Formula: see text]h, have been investigated. The phase formation and crystal structure of the samples were checked by X-ray diffraction (XRD) and Raman spectroscopy. The samples crystallize in the pure perovskite structure that transforms from tetragonal to pseudocubic under doping with La; results that have been confirmed by Rietveld Refinement technique. The estimated average crystallite size of the samples was about 23[Formula: see text]nm. Dielectric parameters (dielectric permittivity and losses) were determined in the temperature range room temperature (RT) — 280∘C and in the frequency range 500[Formula: see text]Hz–2[Formula: see text]MHz. La doping gives rise to a strong decrease of the ferro-to-paraelectric transition temperature, and the frequency dependence of the permittivity shows that the samples with [Formula: see text] and [Formula: see text] reach their resonance frequency. The frequency dependence of impedance and electric modulus properties were studied over a wide frequency range from 1[Formula: see text]kHz to 2[Formula: see text]MHz at various temperatures to confirm the contributions from grains and grain-boundaries. The complex impedance analysis data have been presented in the Nyquist plot which is used to identify the corresponding equivalent circuit and fundamental circuit parameters; it was found that the grain boundaries resistance is dominant at room temperature. The frequency dependence of the parameters permittivity, losses and AC conductivity reveals that the relaxation process is of the Maxwell–Wagner type of interfacial polarization.

Application of electrical impedance spirometry to evaluate respiratory function

A practical method for studying the dynamics of respiratory function associated with the registration of the electrical impedance of conductive biological fluids exhaled by the patient is described. In the model measuring cell, the physical causes and patterns of change in air flow conductivity, saturated with an electrolytic fluid aerosol created by an ultrasonic nebulizer, have been investigated experimentally. The design of a new electrical impedance spirometer in the form of a mouthpiece with electrical sensors, filled with a porous medium impregnated with electrolyte, through which the patient breathes, is developed and tested. To register fluctuations in the magnitude of the impedance modulus, an original hardware and software complex is used made on the basis of a high-speed analog-to-digital converter. Based on electrical impedance analysis data, quantitative and qualitative assessment methods are proposed for the basic spirometric medical indicators characterizing the state and functioning of the patient’s breathing apparatus, such as respiration rate, entry and expiration rate, exhaled air volume, amount and concentration of exhaled lung fluid.

Study of inflammatory factors’ effect on the endothelial barrier using piezoelectric biosensor

This paper used piezoelectric sensor to study the dysfunction of endothelial cell monolayer barrier caused by inflammatory factors. The biocompatible conductive polymer membrane of pPy[pGlu]-pLys was prepared on the surface of the ITO work electrode to improve the interface between the endothelial cell and the electrode. Both the impedance analysis data and the stable plateau stage of sensor's frequency shift indicated that endothelial cells formed a good monolayer barrier on this polymer surface. The response frequency shifts of lipopolysaccharide (LPS)- and histamine-induced endothelial barrier dysfunction were different, which distinguished their different stimulation mechanism. It provided a valuable analysis method for detecting the endothelial barrier function affected by inflammatory factor, and could further promote the application of piezoelectric sensor in cell biology and toxicology research.

Stratification of Fat‐Free Mass Index Percentiles for Body Composition Based on National Health and Nutrition Examination Survey III Bioelectric Impedance Data

Loss of protein mass and lower fat-free mass index (FFMI) are associated with longer length of stay, postsurgical complications, and other poor outcomes in hospitalized patients. Normative data for FFMI of U.S. populations do not exist. This work aims to create a stratified FFMI percentile table for the U.S. population using the large bioelectric impedance analysis data obtained from National Health and Nutrition Examination Surveys (NHANES). Fat-free mass (FFM) was calculated from the NHANES III bioelectric impedance analysis and anthropometric data for males and females ages 12 to >90 years for 3 race/ethnicities (non-Hispanic white, non-Hispanic black, and Mexican American). FFM was normalized by subject height to create an FFMI distribution table for the U.S. Selected percentiles were obtained by age, sex, and race/ethnicity. Data were collapsed by race/ethnicity before and after removing obese and underweight participants to create an FFMI decile table for males and females 12 years and older for the healthy-weight U.S. FFMI increased during adolescent growth but stabilized in the early 20s. The FFMI deciles were similar by race/ethnicity, with age group remaining relatively stable between ages 25 and 80 years. The FFMI deciles for males and females were significantly different. After eliminating the obese and extremely thin, FFMI percentiles remain stable during adult years allowing creation of age- and race/ethnicity-independent decile tables for males and females. These tables allow stratification of individuals for nutrition intervention trials to depict changing nutrition status during medical, surgical, and nutrition interventions.

Analysis of structural and electrical properties of Ni2+:Zn2SiO4 ceramic powders by sol–gel method

Present paper reports on the synthesis and electrical properties of Ni2+:Zn2SiO4 (Zn2−xSiO4 = xNi2+, x = 0.0, 0.25, 0.50 and 0.75 mol%) ceramic powders by a conventional sol–gel method. The structural details of Ni2+:Zn2SiO4 ceramic powders have been investigated from the measurement of XRD, FT-IR, Raman spectral profiles and SEM images. The results reveal that these ceramic powders are all in nanometer sized-grains of spherical forms with willemite structures. The XRD and EDAX results have thus corroborated the successful doping of Ni2+ ions into the Zn2SiO4 matrix. The dielectric real (e′), imaginary (e″) parts, loss tangent (tan δ) and AC conductivity (σac) properties as the function of frequency have been carried out and those are strongly dependent on Ni concentration and this behaviours have been explained on the basis of Maxwell–Wagner type of interfacial space charge polarization. Complex impedance analysis data shows only one semicircle corresponding to the grain boundary volume and thus suggesting that the conduction occurrence through grain boundary volume in Ni2+ doped samples and it has been explained using the Cole–Cole expression. .

Long term assessment of a hybrid electrochemical treatment

Monitoring the performance of systems installed to protect against/halt the corrosion of reinforcing steel in concrete is essential in ensuring that the reinforcing bar (rebar) is adequately protected and remains in a non-corroding state. A chloride contaminated concrete test block containing a hybrid anode system has been periodically monitored over the past 4.5 years to assess the anode current output and thus, the protection offered to the steel. De-polarisation and impedance analysis data have been acquired to calculate steel corrosion rates. Both tests indicated that the steel was passive in the concrete environment and that the anode was able to protect all of the embedded steel despite the difficult geometry of the sample. It was also found that after 2 years it was still possible to drive a high current from the installed anode.

Thigh muscle volume predicted by anthropometric measurements and correlated with physical function in the older adults.

(1) to correlate thigh muscle volume measured by magnetic resonance image (MRI) with anthropometric measurements and physical function in elderly subjects; (2) to predict MRI-measured thigh muscle volume using anthropometric measurements and physical functional status in elderly subjects. Cross-sectional, nonrandomized study. Outpatient clinic in Taiwan. Sixty-nine elderly subjects (33 men and 36 women) aged 65 and older. The anthropometric data (including body height, body weight, waist size, and thigh circumference), physical activity and function (including grip strength, bilateral quadriceps muscle power, the up and go test, chair rise, and five meters walk time) and bioelectrical impedance analysis data (including total body fat mass, fat-free mass, and predictive muscle size) were measured. MRI-measured muscle volume of both thighs was used as the reference standard. The MRI-measured thigh volume was positively correlated with all anthropometric data, quadriceps muscle power and the up and go test as well as fat-free mass and predictive muscle mass, whereas it was negatively associated with age and walk time. In predicting thigh muscle volume, the variables of age, gender, body weight, and thigh circumference were significant predictors in the linear regression model: Muscle volume (cm3) =4226.3－42.5 × Age (year)－955.7 × gender (male=1, female=2) + 45.9 × body weight(kg) + 60.0 × thigh circumference (cm) (r2 = 0.745, P < 0.001; standard error of the estimate = 581.6 cm3). The current work provides evidence of a strong relationship between thigh muscle volume and physical function in the elderly. We also developed a prediction equation model using anthropometric measurements. This model is a simple and noninvasive method for everyday clinical practice and follow-up.

Body Composition Comparison: Bioelectric Impedance Analysis with Dual-Energy X-Ray Absorptiometry in Adult Athletes

The primary purpose of this study was to investigate the accuracy of the DF50 (ImpediMed Ltd, Eight Mile Plains, Queensland, Australia) bioelectrical impedance analysis device using dual-energy x-ray absorptiometry as the criterion in two groups: endurance athletes and power athletes. The secondary purpose was to develop accurate body fat percentage prediction equations for each group based on bioelectrical impedance analysis data and/or the combination of bioelectrical impedance analysis and anthropometric data. Eighty male athletes (40 elite endurance athletes and 40 were power athletes), age 19–48 with body mass indexes ranging from 18.9 to 37.4 were recruited. Anthropometric measurements were taken. Body composition was assessed by dual-energy x-ray absorptiometry and bioelectrical impedance analysis. An athlete-specific bioelectrical impedance analysis prediction equation was developed by stepwise regression analysis using dual-energy x-ray absorptiometry as the criterion and bioelectrical impedance analysis data and anthropometric measurements as predictor variables. The DF50 bioelectrical impedance analysis significantly overestimated body fat percentage by 6.4 ± 0.5 in the entire group (p < .001) and in both the endurance group (6.1 ± .6, p < .001) and the power group (6.7 ± 0.7, p < .001). The endurance and power group showed no significant difference in the error of estimation by bioelectrical impedance analysis (p = .554), indicating that bioelectrical impedance analysis has the same error in both groups. The final prediction equation incorporated both anthropometric variables as well as bioelectrical impedance analysis variables and produced an adjusted r2 of .982 and a standard error of the estimate (SEE) of 1.98 for the entire group. This prediction equation used bioelectrical impedance analysis measurements and anthropometric measurements, specifically trunk measurements, to account for trunk size, a common source of error in bioelectrical impedance analysis equations. Follow-up validation studies are necessary to further validate the equations produced.

Impedance analysis of varnish-modified crystal quartz resonators coupled with FT-IR and FT-Raman: Assessment of the environmental impact on artistic materials in conservation sites

There is an increasing interest in analytical sensing systems for assessing the impact of the environment on the materials of the cultural heritage stored in indoor conservation areas. In this paper, the response of sensors obtained by coating quartz resonators with thin films of artistic varnishes (mastic and dammar), artificially aged under visible or UV radiation, is discussed in terms of their impedance curves around the resonating frequency. Electrodeless quartz crystals are used on account of their enhanced recycling simplicity and lower cost. The ageing under visible radiation induces a systematic negative shift (of the order of hundreds of Hz) and a damping of the impedance curve, with an increase in the impedance minima, which seems to indicate both gravimetric and visco-elastic effects. Controls exhibit only a minor shift, but again in the negative direction. On the other hand, under UV artificial ageing the frequency change is towards more positive values and is more substantial than in the case of visible light ageing. In these impedance spectra, although the overall frequency change appears to be more directly associated with the degree of ageing and/or degradation (thus being a potentially suitable parameter for continuous monitoring in field applications), the alterations in the shape of the curves are important to distinguish different types of ageing. The impedance analysis data is combined with the information retrieved from FT-Raman and FT-IR, also non-destructive techniques. A different rate of ageing, inferred by impedance analysis, is observed in the changes of specific band markers identified in the FT-Raman and FT-IR spectra. In particular, the higher reactivity of mastic versus dammar was highlighted by both methods.

Prevention of the cathode induced electrochemical degradation of [Ru(bpy)3](PF6)2 light emitting devices

Light emitting electrochemical cells based on the tris(2,2′ bipyridyl) ruthenium(II) complex show improved performance if electrochemically stable materials such as Ag are used as the cathode material. In contrast, if Al is used as the cathode such devices undergo degradation when stored in the off-state in inert atmosphere. In this work, the mechanism of the aluminum-induced degradation is investigated. X-ray photoelectron spectroscopy shows that some of the Ru(II) complexes are reduced in the presence of the Al cathode to Ru(I). In addition, secondary ion mass spectrometry depth profiles indicate degradation of the indium tin oxide in devices with Al cathodes. Because of the mixed-valent Ru(II)/(I) states, devices with Al cathodes exhibit unipolar charge injection at voltages below the turn-on voltages. The unipolar charge injection can be described by a theory of charge hopping in mixed-valent redox systems. In addition, impedance analysis data at 0 V bias of devices with Al or Ag cathodes can be fit using simple equivalent electric circuits. In the case of Al devices, the equivalent electric circuit was modified to account for the redox conduction at 0 V bias and an oxide layer at the cathode interface.