93 research outputs found
A Unified Framework for Investigating Aperiodic and Periodic Components in the Hearbeat Dynamics Spectrum: a Feasibility Study
No full textHeart Rate Variability (HRV) series is a widely used, non-invasive, and easy-to-acquire time-resolved signal for evaluating autonomic control on cardiovascular activity. Despite the recognition that heartbeat dynamics contains both periodic and aperiodic components, the majority of HRV modeling studies concentrate on only one component. On the one hand, there are models based on self-similarity and 1/f behavior that focus on the aperiodic component; on the other hand, there is the conventional division of the spectral domain into narrow-band oscillations, which considers HRV as a combination of periodic components. Taking inspiration from a recent parametrization of EEG power spectra, here we evaluate the applicability of a unified modeling framework to quantitatively assess heartbeat dynamics spectra as a mixture of aperiodic and periodic components. The proposed model is applied on publicly-available, real HRV series collected during postural changes from 10 healthy subjects. Results show that the proposed modeling effectively characterizes different experimental conditions and may complement HRV standard analysis defined in the frequency domain
Estimation of Dynamical Noise Power in Unknown Systems
No full textNoise can be modeled as a sequence of random variables defined on a probability space that may be added to a given dynamical system , which is a map on a phase space. In the non-trivial case of dynamical noise , where follows a Gaussian distribution and the system output is , without any specific knowledge or assumption about , the quantitative estimation of the noise power is a challenge. Here, we introduce a formal method based on the nonlinear entropy profile to estimate the dynamical noise power without requiring knowledge of the specific function. We tested the correctness of the proposed method using time series generated from Logistic maps and Pomeau-Manneville systems under different conditions. Our results demonstrate that the proposed estimation algorithm can properly discern different noise levels without any a priori information
Synthesis of a chemiluminescent probe useful for the purification of steroid 5α-reductase
No full textSteroid 5α-reductase is a system of two isozymes (5αR-1 and 5αR-2), which is related to several human disease. The synthesis of a chemiluminescent probe (AZA-LU) useful for purification of 5αR is described. AZA-LU has a chemiluminescence detectable up to 10-15 M and is a good inhibitor (IC50 = 0.5 μM) for rat 5αR-1 expressed in transformed Saccharomyces cerevisiae yeast. Incubation of AZA-LU with yeast lysates, followed by SDS-PAGE, led to the detection of two luminescent protein regions with estimated molecular weights of 26 kDa and 21 kDa
Synthesis of a Chemiluminescent Probe Useful for the Purification of Steroid 5alpha-Reductase
No full textSynthesis of taurine analogues from alkenes
No full text(±)trans 2-Aminocyclohexanesulfonic acid and (±)trans 2-aminocyclo-pentanesulfonic acid were prepared from cyclohexene and cyclopentene respectively by sulfur monochloride addition, followed by oxidation to 2-chlorosulfonic acid and substitution of chlorine
Size distribution of ions and elements in urban and peri-urban areas: evidence of dust resuspension
No full textOn the Time-Invariance Properties of Upper Limb Synergies
No full textIn this paper, we present a novel approach to dynamically describe human upper limb trajectories, addressing the question on whether and to which extent synergistic multi-joint behavior is observed and preserved over time evolution and across subjects. To this goal, we performed experiments to collect human upper limb joint angle trajectories and organized them in a dataset of daily living tasks. We then characterized the upper limb poses at each time frame through a technique that we named repeated-principal component analysis (R-PCA). We found that, although there is no strong evidence on the predominance of one principal component (PC) over the others, the subspace identified by the first three PCs takes into account most of the motion variability. We evaluated the stability of these results over time, showing that during the reaching phase, there is a strong consistency of these findings across participants. In other words, our results suggest that there is a time-invariant low-dimensional approximation of upper limb kinematics, which can be used to define a suitable reduced dimensionality control space for upper limb robotic devices in motion phases
Cardiac sympathetic-vagal activity initiates a functional brain–body response to emotional arousal
No full textA century-long debate on bodily states and emotions persists. While the involvement of bodily activity in emotion physiology is widely recognized, the specificity and causal role of such activity related to brain dynamics has not yet been demonstrated. We hypothesize that the peripheral neural control on cardiovascular activity prompts and sustains brain dynamics during an emotional experience, so these afferent inputs are processed by the brain by triggering a concurrent efferent information transfer to the body. To this end, we investigated the functional brain–heart interplay under emotion elicitation in publicly available data from 62 healthy subjects using a computational model based on synthetic data generation of electroencephalography and electrocardiography signals. Our findings show that sympathovagal activity plays a leading and causal role in initiating the emotional response, in which ascending modulations from vagal activity precede neural dynamics and correlate to the reported level of arousal. The subsequent dynamic interplay observed between the central and autonomic nervous systems sustains the processing of emotional arousal. These findings should be particularly revealing for the psychophysiology and neuroscience of emotions
Restoring bottom-up communication in brain-heart interplay after trauma-focused psychotherapy in breast cancer patients with post-traumatic stress disorder
No full textBackground: The psychological impact of breast cancer (BC) is substantial, with a significant number of patients (up to 32 %) experiencing post-traumatic stress disorder (PTSD). Exploring the emotional aspects of PTSD through the functional brain-heart interplay (BHI) offers valuable insights into the condition. BHI examines the functional interactions between cortical and sympathovagal dynamics. This study aims to investigate changes in functional directional BHI after trauma-focused (TF) psychotherapy, specifically Eye Movement Desensitization and Reprocessing (EMDR), in comparison to treatment as usual (TAU) among BC patients with PTSD. To our knowledge, this study represents the first examination of such changes. Methods: We enrolled thirty BC patients who met the criteria for a PTSD diagnosis, with fourteen receiving EMDR and fifteen receiving TAU over a two- to three-month period. We analyzed changes in the emotional response during a script-driven imagery setting. Quantification of the functional interplay between EEG and sympathovagal dynamics was achieved using the synthetic data generation model (SDG) on electroencephalographic (EEG) and heartbeat series. Our focus was on the difference in the BHI index extracted at baseline and post-treatment. Results: We found statistically significant higher coupling in the heart-to-brain direction in patients treated with EMDR compared to controls. This suggests that the flow of information from the autonomic nervous system to the central nervous system is restored following EMDR-induced recovery from PTSD. Furthermore, we observed a significant correlation between improvements in PTSD symptoms and an increase in functional BHI after EMDR treatment. Conclusions: TF psychotherapy, particularly EMDR, appears to facilitate the restoration of the bottom-up flow of interoceptive information, which is dysfunctional in patients with PTSD. The application of BHI analysis to the study of PTSD not only aids in identifying biomarkers of the disorder but also enhances our understanding of the changes brought about by TF treatments
Additional value of integrated 18 F-choline PET/4D contrast-enhanced CT in the localization of hyperfunctioning parathyroid glands and correlation with molecular profile
No full textPurpose: The localization of hyperfunctioning parathyroid gland(s) (HPTG) in patients with primary hyperparathyroidism (PHPT) with negative or inconclusive first-line imaging is a significant challenge. This study aimed to evaluate the role of integrated 18 F-choline PET/4D contrast-enhanced computed tomography (4DCeCT) in these patients, compare its detection rate and sensitivity with those of 18 F-choline PET/CT and (4DCeCT), and analyse the association between choline metabolism and morphological, biochemical and molecular parameters of HPTG. Methods: We prospectively enrolled 44 PHPT patients with negative or inconclusive first-line imaging. 18 F-Choline PET/CT and 4DCeCT were performed at the same time, and integrated 18 F-choline PET/4DCeCT images were obtained after coregistration. Experienced physicians examined the images. The SUVratio and degree of contrast enhancement were recorded for each positive finding. Histopathology, laboratory and multidisciplinary follow-up were used as the standard of reference. Both the detection rates and sensitivities of the three imaging modalities were calculated retrospectively. Immunohistochemistry was performed to evaluate the molecular profile of HPTGs. Results: 18 F-Choline PET/4DCeCT was positive in 32 of 44 patients with PHPT (detection rate 72.7%), and 31 of 31 surgically treated patients (sensitivity 100%). These results were significantly (p < 0.05) better than those of 18 F-choline PET/CT (56.8% and 80%, respectively) and those of 4DCeCT (54.5 and 74%, respectively). A significant correlation between SUV and calcium level was found. In a multivariate analysis, only calcium level was significantly associated with 18 F-choline PET/4DCeCT findings. SUVratio and Ki67 expression were significantly correlated. Conclusion: Integrated 18 F-choline PET/4DCeCT should be considered as an effective tool to detect PHPT in patients with negative or inconclusive first-line imaging. Choline metabolism is correlated with both calcium level and Ki67 expression in HPTG
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