Minimal information for studies of extracellular vesicles 2018 (MISEV2018): a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

Aeroacoustic model for the prediction of turbulent free jets noise using scanning laser doppler vibrometry

none3nononeCastellini P.; Martarelli M.; Tomasini E.P.Castellini, P.; Martarelli, M.; Tomasini, E. P

Envelope Cepstrum Based Method for Rolling Bearing Diagnostics

The task of identifying a faulty roller element bearing has been so far faced through the use of envelope analysis. As it is well known the main issue linked to such approach is related to the definition of the optimal band-pass filter which can enhance the defect characteristics when the vibration signal is affected by severe noise. The Kurtogram has overcome this limit by letting the optimal band-pass filter be selected in a semi-automatic way, that is by exploiting the potentials of the Spectral Kurtosis. This paper aims at presenting an alternative algorithm which is able to cope with faults characterised by an impulsive-periodic nature. It is well known that faults characterised by periodic-impulsive nature are identifiable by means of cepstral analysis while damages inducing modulation effects are usually assessed via envelope processing. The presented algorithm combine two instruments, since it is based on the Fourier spectrum of the cepstrum squared envelope. Such spectrum allows to isolate the modulation effect by centring the modulating frequency around the DC component. In this paper the algorithm is applied to both synthesized data reproducing typical damaged rolling bearing signals and experimental data. Results achieved by exploiting the proposed algorithm are compared to the ones obtained by applying conventional envelope analysis based on Spectral Kurtosis

Laser doppler myography (LDMi): A novel non-contact measurement method for the muscle activity

Background and aims: Electromyography (EMG) is considered the gold-standard for the evaluation of muscle activity. Transversal and dimensional changes of the muscle, during muscle activity, generate vibrational phenomena which can be measured by Laser Doppler Vibrometry (LDVi). There is a relationship between muscle contraction and vibrational activity, therefore, some information on fundamental muscle parameters can be assessed without contact with LDVi. In this paper, we explore the possibility to relate the EMG signal causing the muscle contraction and the vibrational activity also measureable on the muscle. A novel non-contact measurement method - Laser Doppler myography (LDMi) - aiming to measure the vibrational behavior of muscle during contraction, is presented herein. Correlations with some parameters normally measured with EMG are reported. Materials and methods: The proposed method has been compared with standard superficial EMG (sEMG). Signals produced with sEMG and laser Doppler myography have been simultaneously acquired and processed to test correlations on a population of 20 healthy volunteers. Tests have been carried out on the flexor carpi ulnaris and the tibialis anterior muscles (left and right). Results: Results show that it is possible to measure: The timing of muscle activation (max differences: 440 ms), the amplitude of the signals acquired during activation respect to the signals during rest (S/N), the correlation between the S/N of the sEMG and LDMi signals at different levels of force (P> 0.89), and to assess muscle fatigue. Conclusions: LDMi is a valid measurement technique for the assessment of muscle activity and fatigue. It is a non-contact method and this characteristic could suggest its use together with low level laser therapy pre-, intra- and post-LLLT sessions to evaluate the efficacy and effects of the treatments without the need for invasive electrodes

A non contact approach for the evaluation of large artery stiffness: a preliminary study

BACKGROUND The time from carotid to femoral pulse wave propagation (pulse transit time (PTT)) is required to estimate the carotid-femoral pulse wave velocity (PWV), a reliable index for evaluating large artery stiffness. METHODS In this work, we propose a novel, noncontact laser-based technique, named optical vibrocardiography (VCG), for evaluating PTT from synchronous recordings of the motion of the skin on the neck and the groin. These measurements, which have been demonstrated to be related to the radial displacement of the underlying blood vessels, were performed on 14 healthy subjects. As validation, applanation tonometry was performed to determine PTT between the carotid and the femoral artery. RESULTS PTT evaluated by VCG was not different from applanation tonometry (74.86 +/- 8.63 ms vs. 75.85 +/- 8.61 ms, P = 0.377). CONCLUSIONS Our preliminary results demonstrate that laser-based noncontact measurement in young healthy volunteers is feasible, and yields PTTs that are equivalent to those measured using arterial applanation tonometry. Its clinical application can overcome limitations inherent to a contact method like arterial tonometry