Development of an electrical impedance tomography set-up for the quantification of mineralization in biopolymer scaffolds

Objective. 3D cell cultures are becoming a fundamental resource for in-vitro studies, as they mimic more closely in-vivo behavior. The analysis of these constructs, however, generally rely on destructive techniques, that prevent the monitoring over time of the same construct, thus increasing the results variability and the resources needed for each experiment. Approach. In this work, we focus on mineralization, a crucial process during maturation of artificial bone models, and propose electrical impedance tomography (EIT) as an alternative non-destructive approach. In particular, we discuss the development of an integrated hardware/software system capable of acquiring experimental data from 3D scaffolds and reconstructing the corresponding conductivity maps. We also show how the same software can test how the measurement is affected by biological features such as scaffold shrinking during the culture. Main results. An initial validation, comprising the acquisition of both a non-conductive phantom and alginate/gelatin scaffolds with known calcium content will be presented, together with the in-silico study of a cell-induced mineralization process. This analysis will allow for an initial verification of the systems functionality while limiting the effects of biological variability due to cell number and activity. Significance. Our results show the potential of EIT for the non-destructive quantification of matrix mineralization in 3D scaffolds, and open to the possible long term monitoring of this fundamental hallmark of osteogenic differentiation in hybrid tissue engineered constructs

A broadband current sensor based on the X-Hall architecture

A broadband current sensor, which is fully integrated and galvanically-isolated, is presented in this paper. The current sensor relies only on a Hall-effect probe to realize the magnetic sensing core so as to minimize the cost and the occupied space. Bandwidth limitations of state-of-the-art Hall-effect probes are overcame by combining the novel X-Hall architecture with a wide bandwidth differential-difference current-feedback amplifier. A prototype implemented in 0.16 \u3bcm BCD technology demonstrates a bandwidth wider than 20 MHz. Offset, sensitivity and power consumption are comparable to the state of the art. This is the first Hall-only current sensor achieving a bandwidth higher than 3 MHz

Energy autonomous systems : future trends in devices, technology, and systems

The rapid evolution of electronic devices since the beginning of the nanoelectronics era has brought about exceptional computational power in an ever shrinking system footprint. This has enabled among others the wealth of nomadic battery powered wireless systems (smart phones, mp3 players, GPS, …) that society currently enjoys. Emerging integration technologies enabling even smaller volumes and the associated increased functional density may bring about a new revolution in systems targeting wearable healthcare, wellness, lifestyle and industrial monitoring applications

Validazione di Pulse Wave Velocity e Augmentation Index come metodiche per la valutazione non invasiva della rigidit\ue0 arteriosa

La rigidit\ue0 delle arterie \ue8 alla base di numerose complicanze ed eventi cardiovascolari, nonch\ue9 il principale responsabile della malattia aterosclerotica e dei piccoli vasi. Scopo del nostro studio \ue8 stato quello di validare la misurazione di Pulse Wave Velocity (PWV) e Augmentation Index (AI) come procedura applicabile nella pratica clinica quotidiana per la valutazione della rigidit\ue0 arteriosa. Il nostro lavoro ha coinvolto 45 soggetti sani volontari (23 giovani, et\ue0 media 24\ub13 anni, e 22 adulti, et\ue0 media 55\ub13 anni) e 10 pazienti (64\ub112 anni) con fibrillazione atriale sottoposti a cardioversione elettrica esterna. Le derivazioni periferiche dell\u2019elettrocardiogramma e i flussi arteriosi carotideo e femorale sono stati registrati mediante strumentazione commerciale standard; il polso di pressione radiale \ue8 stato prelevato mediante un tonometro (Millar). Tutta la strumentazione \ue8 stata interfacciata con un computer per consentire la visualizzazione, la memorizzazione e la successiva elaborazione dei segnali. PWV \ue8 stato calcolato come rapporto tra la distanza tra la fossetta giugulare e la congiungente le due spine iliache antero-superiori ed il ritardo della propagazione del flusso tra i siti considerati. L\u2019AI aortico \ue8 stato derivato dalla tonometria radiale e dalla pressione sanguigna periferica brachiale utilizzando una funzione matematica di trasferimento gi\ue0 validata e pubblicata[1]. I valori ottenuti di PWV ed AI sono stati correlati ad et\ue0, sesso e pressione arteriosa. I soggetti patologici sono stati sottoposti a queste indagini prima e dopo la cardioversione per valutare eventuali modifiche indotte dalla terapia. AI aumenta significativamente con l\u2019et\ue0 (p=0,03) mentre \ue8 indipendente dal sesso. PWV \ue8 maggiore nei maschi ed aumenta con l\u2019et\ue0 (p=0,08). I pazienti con FA presentano valori di AI pi\uf9 alti rispetto agli adulti sani (p<0,001), mentre non abbiamo evidenziato differenze significative sia per AI sia per PWV tra i valori ottenuti prima e dopo la cardioversione. Ci\uf2 pu\uf2 essere dovuto alla persistenza dell\u2019adattamento instauratosi nel sistema cardiocircolatorio a causa della patologia. In conclusione, la valutazione di PWV ed AI potrebbe essere uno strumento utile per ottenere un quadro pi\uf9 completo del sistema cardiovascolare di un soggetto anche se sono necessari ulteriori studi a supporto di ci\uf2 La semplicit\ue0, velocit\ue0 di esecuzione e la non-invasivit\ue0 delle metodiche renderebbero le stesse fruibili nella pratica clinica quotidiana e ben accette ai pazienti. 1. Karamanoglu M, O\u2019Rourke MF et al.: An analysis of the relationship between central aortic and peripheral upper limb pressure waves in man. Eur Heart J 1993; 14: 160-167

Usefulness of Finasteride to induce ovulation in a non responder hyperandrogenic woman: birth of a healthy male infant.

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Cell-Based CMOS Sensor and Actuator Arrays

In recent years, increasing knowledge about in vitro cell handling and culturing has encouraged a variety of CMOS- based approaches to stimulate and detect electrical activity of biological cells. This paper outlines in a topical review the scope of cell-based biosensors and actuators for in vitro applications ranging from single-cell detection to multisite probing of complex neural tissue. Recent examples are selected to demonstrate how standard CMOS processes have been used to engineer arrays with different functionality. Index Terms\u2014Cell-based biosensors, cell manipulation, dielec- trophoresis, extracellular recording, image sensors, in vitro, multi- electrode array (MEA), multisite recording, neurons

Proposal of a non-invasive approach for biomechanical follow-up of heart failure patients.

Heart failure (HF) is the most important cause of death in the world. The prognosis is very poor and strictly dependent on the therapy that should be continuously optimized in function of the mechanical behaviour of the ventricle. To follow the evolution of the disease, we are testing an approach based on the biomechanical coupling between failed heart and aorta, which considers end systolic ventricular volume referred to pressure, stroke volume referred to aortic pulse and a new non invasive index of left ventricular contractility validated by Zhong et al. To test the sensitivity of our approach to monitor the HF condition and evolution, a follow up program of 10 HF patients submitted to cardiac resynchronization therapy is on course and will be concluded in the next three months