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PEOPLE@HES-SO – Annuaire et Répertoire des compétences

PEOPLE@HES-SO
Annuaire et Répertoire des compétences

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Potty Philippe

Potty Philippe

Professeur-e HES ordinaire

Compétences principales

Ingénierie médicale

Dispositifs médicaux

Physique Médicale

Physique appliquée

Management de projet

  • Contact

  • Enseignement

  • Publications

Contrat principal

Professeur-e HES ordinaire

Téléphone: +41 32 930 26 22

Haute Ecole Arc - Ingénierie
Espace de l'Europe 11, 2000 Neuchâtel, CH
DING
BSc HES-SO en Microtechniques - Haute Ecole Arc - Ingénierie
  • Dispositifs médicaux
  • Capteurs et instrumentations en bio-ingénierie
  • Biologie
  • Statistiques
  • Réglementation médicale
MSc HES-SO en Engineering - HES-SO Master
  • Dispositifs médicaux

2025

Soft elastomeric optical fibers for oxygen change measurements of blood and living tissues :
Article scientifique ArODES
a thermoplastic polyurethane assessment

Miguel Llera, Edith Laux, Frédéric Flahaut, Laure Jeandupeux, Esteban Alvarez Seoane, Maxime Zerbib, Jean-Charles Beugnot, Philippe Potty

Biomedical Optics Express,  2025, 16, 2, 426

Lien vers la publication

Résumé:

This paper discusses the design, fabrication, and use of thermoplastic polyurethane optical fibers intended for oxygen saturation measurements. It includes an evaluation of the fiber attenuation and the creation of two probes for the measurement assessment. For comparison, a third probe is made using conventional glass optical fibers. The assessment is conducted in two stages: first, absorption measurements are performed using a mixture of methylene blue and intralipid diluted in deionized water; second, a measurement with human blood is conducted to demonstrate the effectiveness of such fibers in measuring blood oxygen saturation. Additionally, a comprehensive study of measurement stability is provided.

2020

Assembly of Liquid-based thermoelectric generator modules based on amine bonding
Article scientifique ArODES

Laure Jeandupeux, Edith Laux, Claudio Prieur, Philippe Potty, Herbert Keppner

Materials Today: Proceedings,  2021, vol. 44, Pt. 4, pp. 3494-3499

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Résumé:

In the previous years, it has been shown that ionic liquids (IL) are good candidates as base material for thermo-electric generators (TEG). Having identified promising ILs, the next step is building a module integrating those liquids and enabling its use with consumer devices. To keep the flexibility given by a liquid TEG, all the involved materials must be flexible. A TEG is composed of three different layers: 1) the bottom electrode foil, 2) a core foil, containing cavities with liquids, and 3) the top electrode foil. The core foil must be flexible, tight, easily shaped and must exhibit a low thermal conductivity. Inspired by microfluidics, polydimethylsiloxane (PDMS) was chosen. The electrode foils have to withstand metal coating and patterning, must be flexible while retaining electrical conductivity, and must not react with the liquids. Unfortunately, PDMS is not easily bonded to another polymer. Moreover, hermetic sealing of the liquids in a cavity while keeping the contact with the electrode is critical. The TEG being serial connected, if one junction fails the entire TEG fails. In this paper, we demonstrate a way to create the module first by using amine-based bonding of the liquids-accepting housing, and then filling the core cavities with liquids featuring different Seebeck coefficients, using a home built vacuum chamber. The results on bonding and filling are encouraging; they ensure tightness of all the 100 TEG contacts between ILs and electrodes. A Seebeck coefficient (SE) of 1 mV∙K−1 was measured, which is inferior to the expected value and thus asking for multiple improvements. However, the results must rather be seen as a proof of concept, especially concerning the sealing of the liquid, and as a step in the manufacturing process of highly integrated liquid-containing devices.

Impact of organic solvents in combination with redox-couples on magnitude of seebeck coefficient, and electrical current in thermoelectric generators
Article scientifique ArODES

Edith Laux, Laure Jeandupeux, Alexandra Kämpfer, Martin Hofmann, Philippe Potty, Herbert Keppner

Materials Today: Proceedings,  2021, 44, 4, 3489-3493

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Résumé:

In previous work it was shown that Ionic Liquids as active substances in thermoelectric generators have the potential to reduce the thermal conductivity as compared to Solid State materials used in conventional TEGs. Furthermore, it was observed that the Seebeck coefficient could be significantly increased. After a large variety of experiments, it appears that the remaining bottleneck coming to high performance TEGs is, first finding ILs with increased negative Seebeck coefficient, and, second sufficient current extraction. Looking at the current it appears, that higher extractions for a given redox-couple concentration are favoured at reduced viscosity. On the way to explore the effect of viscosity-induced current limitation, in a first step, the Ionic liquids are substituted by a low-viscosity organic solvent such as propylene carbonate (PC). The results showed that, indeed, the thermo-current increases significantly. It was further found that the Seebeck coefficient (SE) using PC exhibited values as high as 1.7 mV/K. Such high values were in previous work rather attributed to the use of ionic liquids. Surprisingly, by adding up to 10% of water to PC, the increased current allowed doubling the power, compared to pure PC. The paper studies the effect of combinations of solvent and redox-couples and tries to correlate the effect of water in PC looking at physical properties such as viscosity, but also the effects of charged carrier-attachment at the electrodes.

Assembly of Liquid-based thermoelectric generator modules based on amine bonding
Article scientifique

Potty Philippe

Materials Today: Proceedings, 2020

Résumé:

n the previous years, it has been shown that ionic liquids (IL) are good candidates as base material for thermo-electric generators (TEG). Having identified promising ILs, the next step is building a module integrating those liquids and enabling its use with consumer devices. To keep the flexibility given by a liquid TEG, all the involved materials must be flexible. A TEG is composed of three different layers: 1) the bottom electrode foil, 2) a core foil, containing cavities with liquids, and 3) the top electrode foil. The core foil must be flexible, tight, easily shaped and must exhibit a low thermal conductivity. Inspired by microfluidics, polydimethylsiloxane (PDMS) was chosen. The electrode foils have to withstand metal coating and patterning, must be flexible while retaining electrical conductivity, and must not react with the liquids. Unfortunately, PDMS is not easily bonded to another polymer. Moreover, hermetic sealing of the liquids in a cavity while keeping the contact with the electrode is critical. The TEG being serial connected, if one junction fails the entire TEG fails. In this paper, we demonstrate a way to create the module first by using amine-based bonding of the liquids-accepting housing, and then filling the core cavities with liquids featuring different Seebeck coefficients, using a home built vacuum chamber. The results on bonding and filling are encouraging; they ensure tightness of all the 100 TEG contacts between ILs and electrodes. A Seebeck coefficient (SE) of 1 mV?K?¹ was measured, which is inferior to the expected value and thus asking for multiple improvements. However, the results must rather be seen as a proof of concept, especially concerning the sealing of the liquid, and as a step in the manufacturing process of highly integrated liquid-containing devices.

2001

Stimulation of the left ventricle through the coronary sinus with a newly developed 'over the wire' lead system - Early experiences with lead handling and positioning
Article scientifique

Potty Philippe

Europace, 2001

Lien vers la publication

Résumé:

This report describes the initial clinical results with a newly designed guiding catheter and an 'over the wire' pacing lead based on angiolasty technology to stimulate the left ventricle using the transvenous route via the coronary sinus (OTW-CV lead). In 75% of the 15 patients (6 males, 9 females, mean age of 53 +/- 9 years) with congestive heart failure, access to coronary sinus required less than 2 min; in one patient. the attempt failed. Mean R wave amplitudes plus or minus the standard deviation, measured at apical, mid-ventricular and basal positions the anterior (11.4 +/- 9.2, 10.8 +/- 6.2, 9.3 +/- 6.3 mV) and lateral or posterior veins (10.1 +/- 10.7, 8.6 +/- 6.4, 7.7 +/- 4.3 mV) showed a trend favouring the apex without statistical significance. Pacing impedance, measured at the same sites and vein tributaries, ranged from 670 +/- 191 to 915 +/- 145 ohms. Pacing thresholds measured at apical and mid ventricular sites were significantly lower than at the base in the anterior vein 2.5 +/- 2.8 and 2.8 +/- 1.8 vs 5.6 +/- 2.7 V at 0.5 ms, P<0.001). Thresholds in the lateral/posterior veins showed a similar trend but did not reach statistical significance (3.0 +/- 1.7, 3.6 +/- 1.4 +/- 1.8 V at 0.5 ms). In patients, in whom thresholds were determined in more than one vein, the 'best' mean threshold was 1.6 +/- 0.7 V. The new 'over the wire' lead and guiding catheter system allows uncomplicated access to the coronary sinus and the depth of the coronary vein tributaries. Left ventricular sensing and pacing thresholds are acceptable for chronic use in implanted cardiac rhythm management systems.

2000

Can cardiac resynchronization obviate the need for a heart transplant? A peak oxygen uptake perspective
Article scientifique

Potty Philippe

European Journal of Heart Failure, 2000

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Chronic evaluation of long-term pacing resynchronization for congestive heart failure, relation with acute hemodynamic improvement
Article scientifique

Potty Philippe

European Journal of Heart Failure, 2000

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Résumé:

Atrio-biventricular pacing (ABP) has recently been proposed for treating patients (pts) with drug refractory heart failure (HF) and intraventricular conduction delay (ICD). The aim of this study was to evaluate long-term effects of ABP on cardiac performance and clinical status in pts with severe congestive HF and ICD. Inclusion criterias were chronic and severe (NYHA class III-IV) HF, dilated cardiomyopathy (DCM)(LVEF < 35%, LVEDD > 60 mm), ICD (QRS > 120 msn) and insufficient improvement with standard therapy. Two different biventricular pacing systems were transvenously implanted: 1. Both ventricular leads were connected through a Y bifurcated adapter 2. InSync pacemaker system. LVEDD, LVESD, LVEF, diastolic filling time (DFT), total mitral regurgitation time (tMRT) and rate pressure rise (RPR) were measured by echocardiography at baseline, pre-discharge, 1, 3, 6 and 12 months after implantation. NYHA class, exercise capacity (as METs by treadmill exercise testing with Nanghton protocol), QoL questionnaire (Minnessota Living with HF score) and HRV (SDNN) were evaluated at baseline, 3, 6 and 12 months during follow-up (FU). 11 Pts (mean age 60 + 9 years) with ischemic (n = 7) and non-ischemic (n = 4) DCM, mean NYHA class 3.7 + 0.5, mean LVEF 25.5 ± 7.2%, mean LVEDD 6.9 + 0.7 mm and mean QRS duration 174 4-26 msec entered in this study.

Does baseline qrs-width predict long-term benefit of resynchronization therapy for congestive heart failure?
Article scientifique

Potty Philippe

European Journal of Heart Failure, 2000

Lien vers la publication

Résumé:

Atrio-biventricular pacing (ABP) has recently been proposed for treating patients (pts) with drug refractory heart failure (HF) and intraventricular conduction delay (ICD). The aim of this study was to evaluate long-term effects of ABP on cardiac performance and clinical status in pts with severe congestive HF and ICD. Inclusion criterias were chronic and severe (NYHA class III-IV) HF, dilated cardiomyopathy (DCM)(LVEF < 35%, LVEDD > 60 mm), ICD (QRS > 120 msn) and insufficient improvement with standard therapy. Two different biventricular pacing systems were transvenously implanted: 1. Both ventricular leads were connected through a Y bifurcated adapter 2. InSync pacemaker system. LVEDD, LVESD, LVEF, diastolic filling time (DFT), total mitral regurgitation time (tMRT) and rate pressure rise (RPR) were measured by echocardiography at baseline, pre-discharge, 1, 3, 6 and 12 months after implantation. NYHA class, exercise capacity (as METs by treadmill exercise testing with Nanghton protocol), QoL questionnaire (Minnessota Living with HF score) and HRV (SDNN) were evaluated at baseline, 3, 6 and 12 months during follow-up (FU). 11 Pts (mean age 60 + 9 years) with ischemic (n = 7) and non-ischemic (n = 4) DCM, mean NYHA class 3.7 + 0.5, mean LVEF 25.5 ± 7.2%, mean LVEDD 6.9 + 0.7 mm and mean QRS duration 174 4-26 msec entered in this study.

Is resynchronization between left and right ventricles responsible for improving hemodynamic function of heart failure patients with LBBB?
Article scientifique

Potty Philippe

European Journal of Heart Failure, 2000

Lien vers la publication

1999

Does fusion contribute to the improvement of LV systolic function of heart failure patients when pacing the LV with varying AV delays?
Article scientifique

Potty Philippe

Journal of Cardiac Failure, 1999

Lien vers la publication

1998

Comparison between Three- and Four-Element Windkessel Models to Characterize Vascular Properties of Pulmonary Circulation
Article scientifique

Potty Philippe

Archives of Physiology and Biochemistry, 1998

Lien vers la publication

Résumé:

In 11 anaesthetised pigs the accuracy of the three-element (WK3) and the four-element (WK4) Windkessel models to describe hemodynamic properties of the pulmonary circulation was compared during six different experimental conditions increasing pulmonary arterial pressure: increase in left atrial pressure, increase in alveolar pressure, increase in pulmonary blood flow, endotoxin shock, mechanical obstruction of left pulmonary artery or histamine infusion. Our results showed that WK4 fitted better the data than did WK3 because values of 1-R2 decreased from 6 percent (WK3) to 1.4 percent (WK4) when WK4 was used (P < 0.0005). 1-R2 was an adequate marker of the accuracy of the linear regression used to solve equations of both models. Compliance values estimated by WK4 were decreased by 5% comparatively to WK3 (P = 0.008). However, this difference can be considered as not physiologically relevant. Values of characteristic resistance corresponding to R1 + (L/R2C) in WK4 and to R1 in WK3 were not different (P = 0.22). The relative changes in R1, R2, and C observed due to the different experimental conditions were comparable regardless of the model. In conclusion, the conversion of WK3 in WK4 by adding an inductance, whose physiological meaning is not clear, resulted in an increased statistical accuracy of the model, but did not seem to have relevant influence on parameters or their evolution during experimental conditions.

Pulmonary impedance and right ventricular-vascular coupling in endotoxin shock
Article scientifique

Potty Philippe

Cardiovascular Research, 1998

Lien vers la publication

Résumé:

We tested the hypothesis that right heart failure during endotoxin shock may result from altered ventriculovascular coupling responsible for impeding power transfer to the pulmonary circulation. The changes in vascular pulmonary input impedance and right ventricular contractility produced by low-dose endotoxin infusion were studied in 6 intact anesthetized dogs. Endotoxin insult resulted in pulmonary hypertension (from 22 +/- 2 to 33 +/- 3 mmHg) associated with significant decreases in stroke volume (from 26.9 +/- 4 to 20.2 +/- 3 ml) and right ventricular ejection fraction (from 41 +/- 3 to 32 +/- 2%). The first minimum of input impedance spectrum and zero phase were shifted towards higher frequencies. Input resistance and characteristic resistance were dramatically increased. The latter change contributed to a significant increase in the pulsatile component of total right ventricular power output from 13 to 21%, indicating a reduction in the hydraulic right ventricle power output delivered into the main pulmonary artery. Overall changes in input pulmonary impedance were indicative of increased afterload facing the right ventricle leading to depressed performance. In contrast, right ventricular systolic elastance was simultaneously increased from 0.56 to 0.93 mmHg/ml indicating an increase in right heart contractility. These data suggest that pulmonary hypertension in the setting of experimental endotoxin shock is accompanied by deleterious changes in the pulmonary impedance spectrum, which are responsible for a mismatch of increased contractile state of the right ventricle to the varying hydraulic load ultimately leading to ventricular-vascular uncoupling.

Evidence of non linear espvr through beat-to-beat analysis of a caval occlusion using a time varying elastance model of ventricle
Article scientifique

Potty Philippe

Journal of Biomechanics, 1998

Lien vers la publication

Comparative effect of respiratory cycle on pulmonary and systemic circulation, using beat-to-beat analysis technique
Article scientifique

Potty Philippe

ournal of Biomechanics, 1998

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Correction of pressure waveforms recorded by fluid-filled catheter recording systems: A new method using a transfer equation
Article scientifique

Potty Philippe

Acta Anaesthesiologica Scandinavica, 1998

Résumé:

Pressure measuring systems using fluid-filled catheters can result in the recording of distorted pressure waveforms. It results in phase delay, overestimation of systolic and, to a lesser extent, of diastolic pressure. We designed and evaluated a method to correct this pressure waveform distortion using an appropriate transfer equation obtained from the dynamic response of the fluid-filled catheter. This transfer equation is based on the principle that a fluid-filled catheter recording system is considered as an underdamped dynamic system fully characterized by its natural frequency (omega n) and damping ratio (zeta). Pressure waveforms, simultaneously recorded in vitro or in vivo by a fluid-filled catheter (Pc) and a micromanometer-tipped catheter (Pref), were used to validate the method. Dynamic response of the catheter used was obtained from a fastflush test. The corrected signal (Ppred) was obtained using omega n, zeta and the following transfer equation: d2Pc/dt2 + 2 omega n zeta dPc/dt + omega n 2Pc = C Ppred (t) After correction of Pc, Ppred was compared, using a linear regression, with Pref taken as reference. Our results showed that Ppred was fitted to Pref with excellent coefficient correlation (0.99). The mean error and the standard error of estimate were respectively -1.16 mmHg and 1.4 mmHg. This new method can convert the distorted pressure waveforms transmitted by any fluid-filled catheters into high-fidelity signals. It suppresses the phase delay and the over-estimation of systolic pressure induced by fluid-filled catheters.

1997

Dynamic Cardiomyoplasty Actively Supports Assisted Beats and Improves Telesystolic Elastance (E Max) and End Diastolic Pressure-Volume Regime of Non-assisted Beats
Article scientifique

Potty Philippe

Cardiovascular Surgery, 1997

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1996

Catheter distortion effects on the evaluation of arterial input impedance and related parameters
Article scientifique

Potty Philippe

Engineering in Medicine and Biology Society, 1996

Lien vers la publication

Résumé:

luid-filled catheter-pressure transducer systems are often used to measure pressure in the arterial system. An index is proposed to appreciate, in such systems, the distortion of input impedance at each frequency. Effects on the evaluation of input impedance and some usual derived parameters such as zero-phase frequency, distance to the effective reflection site and characteristic impedance are examined

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