Biology subjects

Pilloni, G.

Publications and source records attributed to Pilloni, G..

4 recordsLinked to original sources

bioRxiv2026

Impedance-Derived Heart Rate and Heart Rate Variability from tDCS Output Voltage: Sensorless Physiological Monitoring During Electrical Neuromodulation

BackgroundTranscranial direct current stimulation (tDCS) devices adjust output voltage to maintain the target current despite varying impedance. Pulsatile blood flow produces beat-synchronous changes in tissue impedance. ObjectiveTo determine whether impedance-derived heart rate (IHR), heart rate variability (IHRV), and respiration (IDR) can be estimated from tDCS output voltage without additional physiological sensors. MethodsA custom analog front-end acquires the tDCS output voltage across its full dynamic DC range and superimposed AC fluctuations with high precision. Beats detected from the AC-coupled signal yielded normal-to-normal intervals for HR, HRV, and interval-derived respiration. Accuracy was quantified as mean absolute error (MAE) in 10 healthy laboratory participants against ECG and respiration-monitor references, and against chest-strap RR intervals in 19 at-home sessions from 10 participants with mild-to-moderate depression. ResultsLaboratory MAEs versus ECG were 0.57 bpm for HR, 9.40 ms for SDNN, and 18.90 ms for RMSSD (r = 0.995, 0.859, and 0.778; N = 10); respiratory-rate MAE was 1.36 breaths/min (r = 0.852; N = 6). Across 1-5 mA of tDCS, the cardiac voltage {Delta}Vcardiac(t) amplitude scaled linearly with current (slope, 0.073 mV/mA; p < 0.001). The pulsatile impedance {Delta}Zcardiac(t) = ({Delta}Vcardiac(t)/Iapplied) amplitude averaged 0.080 {+/-} 0.029 {Omega} (mean {+/-} SD) across 50 participant-current observations, with no significant dependence on intensity (slope, -0.002 {Omega}/mA; p = 0.086). At-home MAEs were 1.43 bpm for HR, 8.86 ms for SDNN, and 24.92 ms for RMSSD (r = 0.995, 0.767, and 0.680; 19 sessions). ConclusionstDCS output voltage contains a recoverable cardiac-synchronous signal arising from pulsatile impedance, enabling HR, HRV, and respiratory monitoring without additional physiological sensors.

bioengineering↗

bioRxiv2025

Flickering white light stimulation at 60 Hz induces strong, widespread neural entrainment and synchrony in healthy subjects

BackgroundWhile the effects of 40 Hz externally-induced neural entrainment have been extensively described, little is known about 60 Hz entrainment in humans. Given the role of 60 Hz in cognition, neuroplasticity and neuropsychiatric disorders, this warrants further investigation. ObjectivesThis pilot study characterizes, for the first time, the neural and somatic response to 60 Hz light entrainment in healthy volunteers, over a 3 week-period. MethodsFourteen volunteers were randomized to receive either 60 Hz flickering white light or constant light as sham (30-min sessions, for 3 weeks, 5 days a week). Neural entrainment was assessed with EEG on days 1, 5 and 19. Salivary cortisol and C-reactive protein (CRP) levels, measured with ELISA, assessed the somatic response to stimulation. Side effects and well-being were monitored via questionnaires. Results60 Hz flickering light induced a strong neural entrainment across visual, parietal, temporal and frontal cortex. The signal was highly synchronous but declined significantly by day 19 compared to day 1, indicating neural habituation. Cortisol and CRP salivary levels were unchanged and the stimulation was well tolerated. ConclusionsTo the best of our knowledge this is the first study to characterize both the neural and the somatic response to flickering light over 3 weeks. The observed neural habituation suggests that neuroplasticity could be induced with repeated stimulations over 3 weeks. 60 Hz stimulation for modulating brain activity and induce neuroplasticity has implications for our basic understanding of brain physiology as well as treatment of psychiatric disorders.

neuroscience↗

bioRxiv2022

Complete sequences of the velvet worm slime proteins reveal that slime formation is enabled by disulfide bonds and intrinsically disordered regions

The slime of velvet worms (Onychophora) is a strong and fully biodegradable protein material, which upon ejection undergoes a fast liquid-to-solid transition to ensnare prey. However, the molecular mechanisms of slime self-assembly are still not well understood, notably because the primary structures of slime proteins are yet unknown. Combining transcriptomic and proteomic studies, we have obtained the complete primary sequences of slime proteins and identified key features for slime self-assembly. The high molecular weight slime proteins contain Cys residues at the N- and C-termini that mediate the formation of multi-protein complexes via disulfide bonding. Low complexity domains in the N-termini were also identified and their propensity for liquid-liquid phase separation established, which may play a central role for slime biofabrication. Using solid-state nuclear magnetic resonance, rigid and flexible domains of the slime proteins were mapped to specific peptide domains. The complete sequencing of major slime proteins is an important step towards sustainable fabrication of polymers inspired by the velvet worm slime.

bioengineering↗

bioRxiv2021

Extremely thermophilic endospores germinate and metabolise organic carbon in sediments heated to above 80°C

Endospores of thermophilic bacteria are widespread in cold seabed environments where they remain dormant during initial burial in accumulating sediments. The temperature increase during sedimentation can be simulated in experimental heating of sediments, resulting in the temperature-dependent activation of different endospore populations from the microbial seed bank. Here we investigated the response of endospore populations to heating at extreme high temperature (80- 99{degrees}C). Metabolites for germination and organic matter degradation (dipicolinic acid and organic acids) revealed both endospore germination and subsequent metabolism at [≥]80{degrees}C. Endospore-forming Firmicutes with the genomic potential for organic carbon and nitrogen transformation were recovered by genome-resolved metagenomics. Genomes from Symbiobacteriales, Thermosediminibacteriales, Moorellales and Calditerricolales encode multiple mechanisms for high temperature degradation of sedimentary organic carbon and features of necromass that accumulate during sediment burial including saccharides, amino and nucleic acids. The results provide insight into the metabolism of novel carbon cycling microorganisms activated at high temperature, and suggest that extremely thermophilic Firmicutes dispersed in the ocean are poised to germinate in response to sediment heating during burial and transform a wide range of organic substrates.

microbiology↗