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IntroductionRegorafenib is an oral multi-targeted tyrosine kinase inhibitor (TKI) indicated for the treatment of various tumor types, including metastatic gastrointestinal stromal tumors (GIST), as a third-line systemic therapy. Erythrocytosis, which is characterized by an increase in erythrocyte count, hemoglobin, and hematocrit levels, has been described as a side effect of some antiangiogenic TKIs but has never been associated with regorafenib administration.Case presentationAn extra-GIST was diagnosed in a 58-year-old woman after she underwent surgery to remove a pelvic mass. Three years later, systemic therapy with imatinib was started due to pelvic disease recurrence. However, after six months, due to disease progression, we prescribed sunitinib, which the patient received for four years. Regorafenib was initiated in June 2019, and after six months, we noted an increase in the erythrocytes’ count and hemoglobin (Hb) levels. Given that the patient had clinical benefit and hematocrit was within normal range, we only monitored the blood cell count and continued to give regorafenib at the same dose. The drug was then stopped for over six weeks due to hospitalization for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, and Hb levels returned to normal. Therefore, we decided to restart regorafenib at a lower dose. However, Hb levels rose again in conjunction with increased hematocrit, resulting in the need for multiple phlebotomies. We attempted to restart regorafenib every other day, but it was unsuccessful, so we stopped it permanently in May 2023, and all values returned to normal.ConclusionRegorafenib may cause secondary erythrocytosis that could not be dose-related, as this case report suggests. Secondary erythrocytosis might be a marker of TKI efficacy, given the patient’s prolonged clinical benefit during regorafenib treatment (48 months). In patients receiving regorafenib, monitoring blood count as well as any symptoms associated with erythrocytosis may be suggested.

This paper presents a suitably general model for resistive displacement sensors where the model parameters depend on the current sensor conditions, thereby capturing wearout and failure, and proposes a novel fault detection method that can be seamlessly applied during sensor operation, providing self-diagnostic capabilities. On the basis of the estimation of model parameters, an innovative self-compensation method is derived to increase the accuracy of sensors subject to progressive wearout. The proposed model and methods have been validated by both numerical simulations and experimental tests on two real resistive displacement sensors, placed in undamaged and faulty conditions, respectively. The fault detection method has shown an accuracy of 97.2%. The position estimation error is < ±0.2% of the full-scale span for the undamaged sensor, while the self-compensation method successfully reduces the position estimation error from ±15% to approximately ±2% of the full-scale span for the faulty sensor.

The possibility to steer floating cells dispersed in water by means of flexural plate waves (FPWs) generated by a 9 mm $\times9$ mm piezoelectric MEMS transducer has been explored. The MEMS transducer has a squared cavity etched out in a silicon substrate formed by a 6 mm $\times6$ mm composite diaphragm made of a piezoelectric aluminum nitride (AlN) layer on top of a doped silicon plate. The piezoelectric layer can be electrically actuated by means of metal interdigital transducers (IDTs) placed over the AlN film at the diaphragm edges. Cell alignment has been sought for by inducing standing FPWs in the diaphragm and in the contacting water layer in the cavity by the one-dimensional (1D) acoustic field pattern obtained by exciting two IDTs located symmetrically with respect to the diaphragm centre. The working principle has been validated by means of 2D finite element modelling and simulations. The MEMS transducer has been fabricated using the PiezoMUMPs process and experimentally tested by exploiting a tailored front-end electronic circuit. Inactive fibroblast cells with an approximate diameter of $15~\mu \text{m}$ have been dispersed in demineralized water within the cavity at a concentration in the order of 105 cells/ml. By applying sinusoidal excitation signals to faced IDTs with zero phase shift and peak amplitude of 10 V, lines of cells spaced by half wavelength $\lambda $ /2 = $56~\mu \text{m}$ have been achieved at 12.5 MHz, in good agreement with theoretical predictions and simulation results.

Neuro-biological variations in the timing of sexual maturation within a species are part of an evolved strategy that depend on internal and external environmental conditions. An increased incidence of central precocious puberty (CPP) has been described in both adopted and “covid-19 pandemic” children. Until recently, it was hypothesised that the triggers for CPP in internationally adopted children were likely to be better nutrition, greater environmental stability, and improved psychological wellbeing. However, following data collected during and after the coronavirus (COVID-19) global pandemic, other possibilities must be considered. In a society with high levels of child wellbeing, the threat to life presented by an unknown and potentially serious disease and the stressful environment created by lockdowns and other public health measures could trigger earlier pubertal maturation as an evolutionary response to favour early reproduction. The main driver for increased rates of precocious and rapidly progressive puberty during the pandemic could have been the environment of “fear and stress” in schools and households. In many children, CPP may have been triggered by the psychological effects of living without normal social contact, using PPE, being near adults concerned about financial and other issues and the fear of getting ill. The features and time of progression of CPP in children during the pandemic are similar to those observed in adopted children. This review considers the mechanisms regulating puberty with a focus on neurobiological and evolutionary mechanisms, and analyses precocious puberty both during the pandemic and in internationally adopted children searching for common yet unconsidered factors in an attempt to identify the factors which may have acted as triggers. In particular, we focus on stress as a potential factor in the early activation of the hypothalamic-pituitary-gonadal axis and its correlation with rapid sexual maturation.

Abstract Objective over the last few decades there has been a progressive decline in the average age of onset of pubertal development stages in both sexes. The increase in the prevalence of childhood obesity seems to play an important role in this phenomenon. Design we undertook a retrospective, longitudinal evaluation of the average age of thelarche and menarche to evaluate the relationship between BMI and weight change during the first years of life and the timing and tempo of puberty. Methods we evaluated data for 577 Italian girls born between 1995 and 2003. We collected the main auxological and clinical parameters, including age at B2 and at menarche, BMI SDS at B2 and menarche, gestational age and birth weight and Z-score change from birth weight (BW) to BMI at B2 and menarche. Results the mean age of B2 was 10.06 ± 1.03 years and the mean age of menarche was 12.08 ± 1.02 years. Age at B2 and menarche were inversely correlated with BMI SDS (p

Abstract Background COVID-19 and its related anti-inflammatory treatment (steroids, immunomodulators) may induce the reactivation of latent bacterial, parasitic, and viral infections. According to our knowledge, no case of disseminated HHV-8-related Kaposi sarcoma (KS) after COVID-19 and its treatment has been described so far. Only one case of cutaneous KS concurrently with COVID-19 has been previously reported. Case presentation We describe a case of disseminated KS in a 61-year-old immunocompetent Albanian man after hospitalization for COVID-19. Methods for literature research We used PubMed as biomedical database for the literature research. We selected keyword combinations including “Kaposi sarcoma,” “HHV-8,” “immunocompetent,” “COVID-19,” “SARS-CoV-2,” and “steroids.” No time or language limitation was set. Titles and abstracts of selected articles were systematically screened. Articles were included in the examination if they were published under free access through the digital library of the University of Brescia (Italy), and provided full text. Articles were excluded if the topic was beyond the aim of our study. Finally, we selected 15 articles. Results We describe a case of KS in COVID-19 patient and postulate that Interleukin-6 (IL-6) activity and steroid-induced immunodeficiency may play a major role in KS emergence. No published case of disseminated KS following COVID-19 in otherwise healthy individuals was found through the systematic literature review, despite the high incidence of COVID-19 in areas with medium–high prevalence of HHV-8 infection. This observation might be explained by the role of individual genetic susceptibility factors. Conclusions SARS-CoV-2 infection and its treatment may lead to reactivation of several latent infections, including HHV-8 and its related clinical syndrome, Kaposi sarcoma.

BackgroundAmong sarcomas, which are rare cancers with an incidence of 24 months. Nine patients had at least one grade 3/4 adverse event, mostly being bone marrow toxicity (n=6).ConclusionsTrabectedin has some anti-tumor activity in some ultra-rare and other rare sarcomas, particularly translocation-related sarcomas, with the well-known manageable safety profile.

Noonan syndrome (NS) is a disorder characterized by a typical facial gestalt, congenital heart defects, variable cognitive deficits, skeletal defects, and short stature. NS is caused by germline pathogenic variants in genes coding proteins with a role in the RAS/mitogen-activated protein kinase signaling pathway, and it is typically associated with substantial genetic and clinical complexity and variability. Short stature is a cardinal feature in NS, with evidence indicating that growth hormone (GH) deficiency, partial GH insensitivity, and altered response to insulin-like growth factor I (IGF-1) are contributing events for growth failure in these patients. Decreased IGF-I, together with low/normal responses to GH pharmacological provocation tests, indicating a variable presence of GH deficiency/resistance, in particular in subjects with pathogenic PTPN11 variants, are frequently reported. Nonetheless, short- and long-term studies have demonstrated a consistent and significant increase in height velocity (HV) in NS children and adolescents treated with recombinant human GH (rhGH). While the overall experience with rhGH treatment in NS patients with short stature is reassuring, it is difficult to systematically compare published data due to heterogeneous protocols, potential enrolment bias, the small size of cohorts in many studies, different cohort selection criteria and varying durations of therapy. Furthermore, in most studies, the genetic information is lacking. NS is associated with a higher risk of benign and malignant proliferative disorders and hypertrophic cardiomyopathy, and rhGH treatment may further increase risk in these patients, especially as dosages vary widely. Herein we provide an updated review of aspects related to growth, altered function of the GH/IGF axis and cell response to GH/IGF stimulation, rhGH treatment and its possible adverse events. Given the clinical variability and genetic heterogeneity of NS, treatment with rhGH should be personalized and a conservative approach with judicious surveillance is recommended. Depending on the genotype, an individualized follow-up and close monitoring during rhGH treatments, also focusing on screening for neoplasms, should be considered.

The occupational risk of operators using display screen equipment (DSE) is usually evaluated according to the extent of time spent in active operator–DSE interactions. Risk assessment is based on activity data collected through questionnaires. We evaluated an original and innovative system that can objectively assess active operator–DSE interactions by collecting electrical impulses generated by the activation of mouse, keyboard and a camera that collects attentive eye-screen fixation. The main aim of this study was to evaluate the system’s performance on an employee sample involved in the task of active reading and copying at a DSE workstation connected to the system. In the context of mandatory health surveillance at work, we enrolled 38 DSE operators with normal neuropsychological and eye assessments who were required to complete two predefined reading and writing tasks. The obtained results show that the system is able to collect activity data derived from operator–DSE interactions through screen fixation, keyboard tapping and mouse handling. In the copying task, the session duration as recorded by the system was highly related to the screen fixation time. In the copying task, mouse and keyboard activities were more strongly related to session duration than screen fixation. For the copying task, it was also possible to obtain individual profiles of operator–DSE interactions while performing the same standardized tasks. Collected data can allow an objective evaluation of active time spent by DSE operators at their workstations, thus allowing a more accurate occupational health risk assessment and management. Prospective analysis of individual operator–DSE interaction profiles can favor the setup of targeted preventive and organizational interventions from an of even wider worker wellbeing perspective.

A passive flexible patch for human skin temperature measurement based on contact sensing and contactless interrogation is presented. The patch acts as an RLC resonant circuit embedding an inductive copper coil for magnetic coupling, a ceramic capacitor as the temperature-sensing element and an additional series inductor. The temperature affects the capacitance of the sensor and consequently the resonant frequency of the RLC circuit. Thanks to the additional inductor, the dependency of the resonant frequency from the bending of the patch has been reduced. Considering a curvature radius of the patch of up to 73 mm, the maximum relative variation in the resonant frequency has been reduced from 812 ppm to 7.5 ppm. The sensor has been contactlessly interrogated by a time-gated technique through an external readout coil electromagnetically coupled to the patch coil. The proposed system has been experimentally tested within the range of 32–46 °C, giving a sensitivity of −619.8 Hz/°C and a resolution of 0.06 °C.

This work presents a novel development of the impact-based mechanism for piezoelectric vibration energy harvesters. More precisely, the effect of an impacting mass on a cantilever piezoelectric transducer is studied both in terms of the tip mass value attached to the cantilever and impact position to find an optimal condition for power extraction. At first, the study is carried out by means of parametric analyses at varying tip mass and impact position on a unimorph MEMS cantilever, and a suitable physical interpretation of the associated electromechanical response is given. The effect of multiple impacts is also considered. From the analysis, it emerges that the most effective configuration, in terms of power output, is an impact at the cantilever tip without a tip mass. By changing the value of the tip mass, a sub-optimal impact position along the beam axis can also be identified. Moreover, the effect of a tip mass is deleterious on the power performance, contrary to the well-known case of a resonant energy harvester. A mesoscale prototype with a bimorph transducer is fabricated and tested to validate the computational models. The comparison shows a good agreement between numerical models and the experiments. The proposed approach is promising in the field of consumer electronics, such as wearable devices, in which the impact-based device moves at the frequencies of human movement and is much lower than those of microsystems.

This work proposes a mono-axial piezoelectric energy harvester based on the innovative combination of magnetic plucking and indirect impacts, e.g., impacts happening on the package of the harvester. The harvester exploits a permanent magnet placed on a non-magnetic mass, free to move within a predefined bounded region located in front of a piezoelectric bimorph cantilever equipped with a magnet as the tip mass. When the harvester is subjected to a low-frequency external acceleration, the moving mass induces an abrupt deflection and release of the cantilever by means of magnetic coupling, followed by impacts of the same mass against the harvester package. The combined effect of magnetic plucking and indirect impacts induces a frequency up-conversion. A prototype has been designed, fabricated, fastened to the wrist of a person by means of a wristband, and experimentally tested for different motion levels. By setting the magnets in a repulsive configuration, after 50 s of consecutive impacts induced by shaking, an energy of 253.41 μJ has been stored: this value is seven times higher compared to the case of harvester subjected to indirect impacts only, i.e., without magnetic coupling. This confirms that the combination of magnetic plucking and indirect impacts triggers the effective scavenging of electrical energy even from low-frequency non-periodical mechanical movements, such as human motion, while preserving the reliability of piezoelectric components.

The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 mm × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage Vb between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of Vb, thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics®. The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range Vb = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying Vb = 0 in transmission and Vb = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency.

Multi-converter piezoelectric harvesters based on mono-axial and bi-axial configurations are proposed. The harvesters exploit two and four piezoelectric converters (PCs) and adopt an impinging spherical steel ball to harvest electrical energy from human motion. When the harvester undergoes a shake, a tilt, or a combination of the two, the ball hits one PC, inducing an impact-based frequency-up conversion. Prototypes of the harvesters have been designed, fabricated, fastened to the wrist of a person by means of a wristband and watchband, and experimentally tested for different motion levels. The PCs of the harvesters have been fed to passive diode-based voltage-doubler rectifiers connected in parallel to a storage capacitor, Cs = 220 nF. By employing the mono-axial harvester, after 8.5 s of consecutive impacts induced by rotations of the wrist, a voltage vcs(t) of 40.2 V across the capacitor was obtained, which corresponded to a stored energy of 178 μJ. By employing the bi-axial harvester, the peak instantaneous power provided by the PCs to an optimal resistive load was 1.58 mW, with an average power of 9.65 μW over 0.7 s. The proposed harvesters are suitable to scavenge electrical energy from low-frequency nonperiodical mechanical movements, such as human motion.

A technique and electronic circuit for contactless electromagnetic interrogation of piezoelectric micro-electromechanical system (MEMS) resonator sensors are proposed. The adopted resonator is an aluminum-nitride (AlN) thin-film piezoelectric-on-silicon (TPoS) disk vibrating in radial contour mode at about 6.3 MHz. The MEMS resonator is operated in one-port configuration and it is connected to a spiral coil, forming the sensor unit. A proximate electronic interrogation unit is electromagnetically coupled through a readout coil to the sensor unit. The proposed technique exploits interleaved excitation and detection phases of the MEMS resonator. A tailored electronic circuit manages the periodic switching between the excitation phase, where it generates the excitation signal driving the readout coil, and the detection phase, where it senses the transient decaying response of the resonator by measuring through a high-impedance amplifier the voltage induced back across the readout coil. This approach advantageously ensures that the readout frequency of the MEMS resonator is first order independent of the interrogation distance between the readout and sensor coils. The reported experimental results show successful contactless readout of the MEMS resonator independently from the interrogation distance over a range of 12 mm, and the application as a resonant sensor for ambient temperature and as a resonant acoustic-load sensor to detect and track the deposition and evaporation processes of water microdroplets on the MEMS resonator surface.

This paper describes a piezoelectric energy harvester employing a snap-through buckling (STB) mechanism for frequency-up conversion (FuC). The harvester consists of two main components: a bistable mechanical structure and one piezoelectric cantilever beam. The device is designed by means of analytical methods and numerical simulations. A proof-of-concept prototype is manufactured and tested under low frequency mechanical excitation. Experimental results show that, if the STB is induced, from the second stable configuration back to the undeformed one, the FuC is obtained and the response of the beam presents frequency components in a wide range, even though the resonant frequency of the cantilever beam is not excited. The results are hence in agreement with the expected behavior: if the device, forced in the second stable configuration, is subject to a low-frequency excitation whose amplitude exceeds a threshold, STB is triggered and the ensuing FuC provokes a widening of the beam vibrations frequency range and consequently a significant effectiveness in terms of power output. A maximum power of 4 mW is obtained by using an optimal resistive load as STB from a stable configuration of the bistable mechanism to the other one is triggered; a maximum energy of 4.5 μ J is obtained in case of a rectifier circuit with storage capacitor.

In this paper, the possibility to steer and confine live human cells by means of acoustic waves, such as flexural plate waves (FPWs), generated by piezoelectric actuators applied to non-piezoelectric substrates, has been explored. A device with two lead zirconate titanate (PZT) actuators with an interdigital transducer (IDT) screen-printed on an alumina (Al2O3) substrate has been fabricated and tested. The experimental results show that, by exciting the actuators at their resonant frequencies, FPW modes are generated in the substrate. By exploiting the device, arrangements of cells on lines at frequency-dependent distances have been obtained. To maintain the alignment after switching off the actuator, cells were entrapped in a fibrin clot that was cultured for several days, enabling the formation of cellular patterns.

Crizotinib is an efficacious and well-tolerated drug in the management of ALK-positive lung cancer. Crizotinib treatment, however, is rarely complicated by the occurrence of acute interstitial lung disease (ILD) that is often fatal. There is no treatment for this serious adverse event. We report a female non-small cell lung cancer patient who developed ILD after a few days of crizotinib therapy. She showed a significant improvement after a high dose of pulse corticosteroid therapy, both radiologically and clinically. Unfortunately, the patient subsequently developed an aspergillosis superinfection leading to death. Our experience suggests that high-dose steroid therapy may be efficacious in the management of a severe complication of crizotinib therapy. However, potent antifungal therapy should be considered to prevent the risk of severe aspergillosis.

Zinc oxide (ZnO, n-type) and copper oxide (CuO, p-type) nanowires have been synthesized and preliminarily investigated as innovative materials for the fabrication of a proof-of-concept thermoelectric device. The Seebeck coefficients, electrical conductivity and thermoelectric power factors (TPF) of both semiconductor materials have been determined independently using a custom experimental set-up, leading to results in agreement with available literature with potential improvement. Combining bundles of ZnO and CuO nanowires in a series of five thermocouples on alumina leads to a macroscopic prototype of a planar thermoelectric generator (TEG) unit. This demonstrates the possibility of further integration of metal oxide nanostructures into efficient thermoelectric devices.

ABSTRACT: Objective: Adrenocortical carcinoma (ACC) is a rare disease often associated with hormonal hypersecretion. Hypercortisolism is the most common endocrine syndrome associated with ACC. Abiraterone acetate is a selective and irreversible inhibitor of cytochrome P450 17A1 that is currently used in the treatment of metastatic castration-resistant prostate cancer. The drug induces a profound suppression of both androgen and cortisol secretion and it is a plausible candidate for medical treatment of Cushing's syndrome. We evaluated the hormonal effects of abiraterone administration in a patient with Cushing's syndrome induced by heavily pre-treated metastatic ACC.Methods: A 50-year-old woman with ACC, suffering from severe and unmanageable Cushing's syndrome despite mitotane therapy, received oral abiraterone at 500 mg/day.Results: After 9 days of treatment, the patient experienced a dramatic improvement in autonomy and deambulation, reduction of edema, better control of blood pressure and glycemia, serum potassium normalization, restoration of the sleep-wake rhythm, and disappearance of mental confusion episodes. Hormonal laboratory tests showed a marked reduction in circulating androgen levels and urinary cortisol excretion (urinary free cortisol levels lowered from 1,863 to 520 μg/24 h). Abiraterone therapy was interrupted due to subsequent deterioration of the patient's condition caused by the progression of ACC.Conclusions: Abiraterone can be an effective medical treatment in the management of Cushing's syndrome induced by ACC. This preliminary observation warrants confirmation in a prospective clinical trial.Abbreviations: ACC = adrenocortical carcinoma

We report the case of a 67-year-old man affected by metastatic esophageal cancer. The patient developed a symptomatic heart metastasis presenting as mimicking ST-segment elevation myocardial infarction. Cardiac magnetic resonance imaging (MRI) documented the presence of a mass in the apex and septum of the left ventriculum. The dissemination of cancer was confirmed by the detection of circulating tumor cells (CTCs) in the peripheral blood, measured by the CellSearch System (Veridex, LLC, Raritan, N.J., USA). The blood sample drawn at cardiac disease progression revealed the presence of 2 CTCs per 7.5 ml of blood. This report highlights the potential role of CTCs as markers of metastatic spread.

Contactless readout of passive LC sensors composed of a capacitance sensor connected to a coil can be performed through an electromagnetically coupled readout coil set at distance d. Resonant frequency fs and Q-factor QS of the LC sensor can be extracted from the measurement of the impedance at the readout coil by using a technique theoretically independent of d. This work investigates the effects on the measurement accuracy due to the unavoidable parasitic capacitance CP in parallel to the readout coil, which makes the measured values of fs and QS dependent on d. Numerical analysis and experimental tests confirm such dependence. To overcome this limitation, a novel electronic circuit topology for the compensation of CP is proposed. The experimental results on assembled prototypes show that for a LC sensor with fs ≈ 5.48 MHz a variation of less than 200 ppm across an interrogation distance between 2 and 18 mm is achieved with the proposed compensation circuit.

A Current-Mode (CM) TransImpedance Amplifier (TIA) based on Second Generation Current Conveyors (CCIIs) for capacitive microsensor measurements is presented. The designed electronic interface performs a capacitance-to-voltage conversion using 3 CCIIs and 3 resistors exploiting a synchronous-demodulation technique to improve the overall detection sensitivity and resolution of the system. A CM-TIA solution designed at transistor level in AMS0.35 µm integrated CMOS technology with a power consumption lower than 900 µW is proposed. Experimental results obtained with a board-level prototype show linear behavior of the proposed interface circuit with a resolution up to 34.5 fF and a sensitivity up to 223 mV/nF, confirming the theoretical expectations.

Coil-coupled passive sensors can be interrogated without contact, exploiting the magnetic coupling between two coils forming a telemetric proximity link. A primary coil connected to the interface circuit forms the readout unit, while a passive sensor connected to a secondary coil forms the sensor unit. This work is focused on the interrogation of sensor units based on resonance, denoted as resonant sensor units, in which the readout signals are the resonant frequency and, possibly, the quality factor. Specifically, capacitive and electromechanical piezoelectric resonator sensor units are considered. Two interrogation techniques, namely a frequency-domain technique and a time-domain technique, have been analyzed, that are theoretically independent of the coupling between the coils which, in turn, ensure that the sensor readings are not affected by the interrogation distance. However, it is shown that the unavoidable parasitic capacitance in parallel to the readout coil introduces, for both techniques, an undesired dependence of the readings on the interrogation distance. This effect is especially marked for capacitance sensor units. A compensation circuit is innovatively proposed to counteract the effects of the parasitic input capacitance, and advantageously obtain distance-independent readings in real operating conditions. Experimental tests on a coil-coupled capacitance sensor with resonance at 5.45 MHz have shown a deviation within 1.5 kHz, i.e., 300 ppm, for interrogation distances of up to 18 mm. For the same distance range, with a coil-coupled quartz crystal resonator with a mechanical resonant frequency of 4.432 MHz, variations of less than 1.8 Hz, i.e., 0.5 ppm, have been obtained.

In this paper an energy harvesting system based on a piezoelectric converter to extract energy from airflow and use it to power battery-less sensors is presented. The converter is embedded as a part of a flexure beam that is put into vibrations by von Karman vortices detached from a bluff body placed upstream. The vortex street has been investigated by Computational Fluid Dynamics (CFD) simulations, aiming at assessing the vortex shedding frequency as a function of the flow velocity. From the simulation results the preferred positioning of the beam behind the bluff body has been derived. In the experimental characterization the electrical output from the converter has been measured for different flow velocities and beam orientations. Highest conversion effectiveness is obtained by an optimal orientation of the beam, to exploit the maximum forcing, and for flow velocities where the repetition frequency of the vortices allows to excite the beam resonant frequency at its first flexural mode. The possibility to power battery-less sensors and make them autonomous has been shown by developing an energy management and signal conditioning electronic circuit plus two sensors for measuring temperature and flow velocity and transmitting their values over a RF signal. A harvested power of about 650 μW with retransmission intervals below 2 min have been obtained for the optimal flow velocity of 4 m/s.

This paper presents a measurement technique and system for the contactless interrogation of capacitive sensors via electromagnetic coupling. The interrogation unit employs a primary coil to periodically excite the capacitive sensor connected to a secondary coil forming an LC resonant circuit. When the excitation to the primary coil is switched off the damped response of the LC circuit is detected. As a fundamental advantage compared to techniques based on reflected impedance, this approach ensures that the readout frequency is to first order independent of the interrogation distance between the two coils. The system has been tested with reference capacitors and with a capacitive liquid level sensor. The experimental results are in a good agreement with theoretical expectations and show a sensitivity of about −23 kHz/pF at 5.4 MHz and the possibility to operate with interrogation distances up to few centimeters.

A Micro Electro-Mechanical System (MEMS) that allows to measure an external force applied to a probe tip exploiting an electrical servo-assisted mechanism based on position feedback is presented. The sensor architecture keeps the position of the probe tip fixed by driving a pair of variable-area electrostatic actuators in a feedback loop controlled by a variable-gap capacitive sensor. By adjusting specific loop parameters, the force sensitivity can be finely tuned electrically. Sub-nanonewton measurement range is achieved with high flexibility in setting the tip working point, making the system promising for measuring forces generated by living biological cells.

The possibility to generate acoustic modes based on FPWs (Flexural Plate Waves) in a generic non-piezoelectric substrate for microfludic applications by means of piezoelectric actuators has been explored and described in this paper. The FPW acoustic modes are generated by means of actuators made of Lead Zirconate Titanate (PZT) layers with InterDigital Transducers (IDTs) screen-printed on alumina (Al2O3) substrate. The experimental results show that, by exciting the resonances of the actuators, circular vortex rotations are obtained in a fluid drop placed on the substrate between the IDTs. Micrometric particles dispersed in the drop allow to demonstrate that standing waves can be generated in the liquid obtaining particle accumulation along circular lines. These results suggest the possibility to employ the proposed actuators for fluid mixing and controlled positioning of dispersed particles.