Torsional oscillation monitoring by means of a magnetoelastic resonator: modeling and experimental functionalization to measure viscosity of liquids

A new application of a high sensitivity magnetoelastic resonator able to measure period and dampingconstant of low frequency torsional oscillation is described and validated by experimental tests. Thesensitive parameter is the amplitude of resonant magnetoelastic waves in the soft ferromagnetic core(Fe62.5Co6Ni7.5Zr6Cu1Nb2B15amorphous ribbon). The theoretical model of the device has been developed,correlating torsional oscillations to the friction force applied by the fluid in which they occur. Thus,an accurate indirect evaluation of fluid viscosity has been demonstrated. The main prerogative of theproposed sensor is to work without contact with the oscillating mechanism. As experimental validation,viscosity of UHT milk was measured versus different fat content. The experimental comparison with astandard rheometer demonstrates the new device competitiveness in the measure of low viscosity fluidsat low share rate. Moreover, the detected behaviors at increasing temperature are in agreement withprevious literature. In perspective, the new magnetoelastic resonators application can be very ductileand effective in on-line monitoring of viscosity change with time to control composition, degradation orcontamination of liquids

Light Electrospun Polyvinylpyrrolidone Blanket for Low Frequencies Sound Absorption

Light polymeric soundproofing materials (density = 63 kg/m3) of interest for the transportation industry were fabricated through electrospinning. Blankets of electrospun polyvinylpyrrolidone (average fiber diameter = (1.6 ± 0.5) or (2.8 ± 0.5) μm) were obtained by stacking disks of electrospun mats. The sound absorption coefficients were measured using the impedance tube instrument based on ASTM E1050 and ISO 10534–2. For a given set of disks (from a minimum of 6) the sound absorption coefficient changed with the frequency (in the range 200–1600 Hz) following a bell shape curve with a maximum (where the coefficient is greater than 0.9) that shifts to lower frequencies at higher piled disks number and greater fiber diameter. This work showed that electrospinning produced sound absorbers with reduced thickness (2–3 cm) and excellent sound-absorption properties in the low and medium frequency range

Organic Electrochemical Transistor Immuno-Sensors for Spike Protein Early Detection

The global COVID-19 pandemic has had severe consequences from the social and economic perspectives, compelling the scientific community to focus on the development of effective diagnostics that can combine a fast response and accurate sensitivity/specificity performance. Presently available commercial antigen-detecting rapid diagnostic tests (Ag-RDTs) are very fast, but still face significant criticisms, mainly related to their inability to amplify the protein signal. This translates to a limited sensitive outcome and, hence, a reduced ability to hamper the spread of SARS-CoV-2 infection. To answer the urgent need for novel platforms for the early, specific and highly sensitive detection of the virus, this paper deals with the use of organic electrochemical transistors (OECTs) as very efficient ion-electron converters and amplifiers for the detection of spike proteins and their femtomolar concentration. The electrical response of the investigated OECTs was carefully analyzed, and the changes in the parameters associated with the transconductance (i.e., the slope of the transfer curves) in the gate voltage range between 0 and 0.3 V were found to be more clearly correlated with the spike protein concentration. Moreover, the functionalization of OECT-based biosensors with anti-spike and anti-nucleocapside proteins, the major proteins involved in the disease, demonstrated the specificity of these devices, whose potentialities should also be considered in light of the recent upsurge of the so-called "long COVID" syndrome

Microconfined flow-based imaging methods to study red blood cell deformability and clustering in vitro

An in vitro systematic fluid dynamic investigation of RBC suspensions flowing in a microcirculation-mimicking silicon device containing a network of microchannels of diameter comparable to cell size to investigate RBC membrane viscoelastic properties