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Pulmonary function tests are vital for detecting pathologies, especially chronic obstructive pulmonary diseases (COPD), emphasizing the importance of assessing lung parenchyma involvement in maintaining proper gas exchange. Electrical impedance tomography (EIT) offers a non-invasive alternative for respiratory function evaluation while preserving natural breathing. We propose using EIT to detect lung parenchyma conditions by analyzing tidal volume patterns (by averaging the impedance image) in the frequency domain. Twenty COPD patients underwent simultaneous evaluation with a pneumotachometer and an EIT device, performing three 30-second respiratory maneuvers. FFT spectra analysis yielded parameters, including the area under the curve and quartiles (25 %, 50 %, 75 %) of power values in six frequency regions. Correlations between these parameters and clinical test results (pulmonary diffusing capacity and arterial blood gas analysis) revealed significant associations, particularly with PCO2. Multiple linear regression analysis predicted PCO2 with an R2adj = 0.827, suggesting the potential for noninvasively detecting lung parenchyma affectation by correlating FFT bioimpedance ventilatory patterns with gas exchange performance in COPD patients. [ABSTRACT FROM AUTHOR]

Spirometry is a test for the diagnosis of chronic obstructive pulmonary disease. It is a technique that can be intolerant due to the essential use of a mouthpiece and a clamp. This study proposes the use of electrical impedance tomography to measure respiratory parameters. Patients underwent spirometry and three respiratory exercises. The impedance signals were convolved, and the resultant was analyzed by fast Fourier transform. The frequency spectrum was divided into seven segments (R1 to R7). Each segment was represented in terms of quartiles (Q25%, Q50%, Q75%). Each quartile of each segment was correlated with the spirometric parameters to obtain a fitting equation. FVC was correlated 70% with the 3 quartiles of R7, 3 equations were obtained with a fit of 60%. FEV1 correlated 70% with the Q50% of R7, obtaining an equation with a fit of 40%. FEV1/FVC correlated 69% with Q75% of R2, obtaining an equation with a fit of 60%. Spirometric parameters can be estimated from the implied carrier frequency components of the ventilatory impedance signal. [ABSTRACT FROM AUTHOR]

Background/aims: While stress has been implicated in functional dyspepsia (FD), the mechanisms by which stress results in symptoms are not well defined. The aim of the current study was to assess gastric myoelectric and autonomic changes in response to a physical stressor in youth with FD.Methods: In a group of healthy controls and pediatric FD subjects, we recorded ECG and EGG signals 30 min before and 60 min after, a cold pressor task (CPT). Gastric EGG and heart rate variability (HRV) parameters were calculated in pre- and post-CPT stages and in short intervals.Results: The pre-CPT percent tachygastria was higher in FD subjects as compared to controls. However, CPT did not induce any EGG changes in either controls or FD subjects and the two groups did not differ from each other post-CPT. The CPT resulted in an increase in HRV and standard deviation of NN intervals in controls; there was no change in any HRV parameter in FD subjects.Conclusions: Acute physical stress does not appear to induce gastric electrical abnormalities in youth with FD. Youth with FD appear to lack the normal flexible autonomic response to a physical stressor. [ABSTRACT FROM AUTHOR]

Background: Meal‐related symptoms are common in paediatric functional dyspepsia (FD). There are only a small number of paediatric studies assessing mechanisms for meal‐related symptoms, and these have not utilized Rome IV criteria. The aim of the current study was to assess gastric myoelectric and autonomic nervous system (ANS) responses to both liquid and solid meals in youth with Rome IV‐defined FD. Methods: In healthy controls (N = 14) and youth with FD (N = 12), we recorded electrocardiograph (to assess heart rate variability; HRV) and electrogastrograph (EGG) signals before and after two test meals, one liquid and one solid. EGG parameters and HRV were assessed for the entire pre‐ and postprandial periods and in short time intervals. Additionally, liquid gastric emptying was assessed utilizing a 13C‐acetate breath test. Key Results: During the EGG, the dominant power increased with both meals in controls but not patients with FD. During HRV assessment, the low frequency to high frequency ratio was higher after the liquid meal in controls, despite being similar preprandial, as compared to patients with FD. In controls, both standard deviation of normal to normal waves (SDNN) and root mean square of successive ECG R peaks (R‐R interval) differences (rMSSD) increased after the liquid meal (but not after the solid meal) in controls but not patients with FD. Conclusions and Inferences: Youth with Rome IV‐defined FD lacks the normal postprandial EGG dominant power response or autonomic nervous system response following a liquid meal. The latter appears to indicate a lack of ANS flexibility. [ABSTRACT FROM AUTHOR]

Electrical bio-impedance measurements were conducted on local strawberry fruits. A non-destructive device was designed to obtain the impedance spectrum of the whole fruit. Four electrical variables were tested: low frequency resistor R0 (related to extracellular resistances), the high frequency resistor R∞ (related to intracellular resistances), and constant phase element (magnitude and phase, related to the membrane capacitances and heterogeneity, respectively). In parallel with the electrical bio-impedance measurement, color and firmness were correlated to the ripeness stage. The results indicated that the strawberries at the highest stage of ripeness had significantly lower constant phase element and R0 values. [ABSTRACT FROM AUTHOR]

Synthesis and application of different nanomaterials are the fast-growing fields of research due to nanoparticles' unique properties. Nanoparticles-based materials are used in different fields, such as silver nanoparticles as antiseptics and titanium oxide as photocatalyst. Some drugs based on metallic nanoparticles, such as colloidal iron, are already approved by FDA. However, there is a growing concern about the environmental safety of the materials and that their possible accumulation within living organisms, including humans, may cause negative effects. Nanoparticles' toxicity is widely investigated, but it is still difficult to assess their accumulation in tissue non-invasively. Our research group is studying different applications of electrical bioimpedance, mainly in the biomedical field, so the purpose of this work was to assess the possibility of sensing the accumulation of different nanoparticles by electrical bioimpedance. We used different types of tissues (heart, muscle, liver, and kidney) as ex vivo models. Nanoparticles (mainly metallic) were dissolved in medical-grade saline and injected separately into tissue samples. Electrical bioimpedance before and after nanoparticles injection was recorded with potentiostat SP-150 (BioLogic Science Instrument). Meanwhile, no common pattern was observed, it was seen that almost all nanomaterials changed one or both electrical bioimpedance parameters (module and phase). Likewise, different types of tissues respond differently to the nanoparticles: muscle tissue was the least responsive and heart tissue presented the most notorious changes. As a conclusion, we have seen that nanoparticles accumulation can be assessed by electrical bioimpedance in ex vivo model, so, in vivo experiments must be conducted. [ABSTRACT FROM AUTHOR]

Electrical bioimpedance is a non-invasive and radiation-free technique that was proposed to be used in different clinical areas, however, its practical use is limited due to its low capacity to discriminate between tissues. In order to overcome this limitation, our research group proposes to incorporate the contrast media into the electrical bioimpedance procedure. The main objective of the present study was to assess the crystalloid solutions as a possible contrast media to discriminate between different tissue types in the bioimpedance technique. Two medical-grade crystalloid solutions (Hartmann and NaCl 0.9%) were injected into three biological ex vivo models: kidney, liver, and brain. BIOPAC system was used to acquire bioimpedance data before and after the injections. The data was adjusted to the Debye electrical model. The analysis of measured values showed substantial bioimpedance disparities in tissues subjected to isotonic solutions. The NaCl solution exhibited more pronounced changes in electrical parameters compared to the Hartmann solution. Similarly, NaCl solution displayed superior discriminatory capabilities among tissues, with variations of 465%, 157%, and 206%. Distinct spectral modifications were identified, with tissues demonstrating unique responses at each frequency of analysis relative to untreated tissue. Variations in bandwidth alterations were discernible among tissues, providing clear distinctions. In conclusion, the research showed that the crystalloid solution exhibited greater sensitivity and superior tissue contrast at specific frequencies. This study's findings underscore the feasibility of implementing crystalloid solutions to enhance tissue discrimination, similar to the effects of contrast agents. • Crystalloid solutions change impedance parameters in ex vivo models. • In the liver, the Hartman solution causes a decrease in bandwidth change. • The data presented acceptable adjustments to the Debye model. • Crystalloid solutions are the viable contrast media for bioimpedance applications. [ABSTRACT FROM AUTHOR]