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Ultrasound Basics
Published in Massimo Zambon, Ultrasound of the Diaphragm and the Respiratory Muscles, 2022
Sound is vibration of a physical medium. In clinical ultrasound, a mechanical vibrator, known as the transducer, is placed in contact with a surface (i.e., the skin, but it can be an internal surface such as the oesophagus) to create tissue vibrations (sound waves). The core of every transducer consists of piezoelectric crystals. Piezoelectricity is the process of using crystals to convert mechanical energy into electrical energy, or vice versa. Therefore, a transducer converts (or transduces) electrical energy to or from mechanical energy. The amplitudes of the returning echoes are represented as pixels of varying brightness along the vertical axis of the display. The brightness correlates with the strength of the returning signal.
Electrophysiology
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
The input transducer is of two different types, namely, active and passive transducers. Active transducers convert physical quantities into electrical signals. The examples of active sensors are piezo-electric devices, solar cells and thermocouples. Passive transducers are used to convert the changes in the physical variables into variations in capacitance, inductance and resistance.
Oocyte Pick-Up Technique
Published in Arianna D'Angelo, Nazar N. Amso, Ultrasound in Assisted Reproduction and Early Pregnancy, 2020
An older but readily available method for a probe cover was to use a finger of a sterile surgical glove. This practice should be avoided because of the risk that it creates air bubbles in the gel (between the probe and glove part), which compromises the ultrasound view. Specialized probe covers should be preferred. The transducer needle guide should be simple to attach after a sterile cover has been applied. The transducer should be cleaned and disinfected between procedures following the local protocols. Chapter 19 elaborates on infection control methods, which all health-care professionals working in IVF units must be familiar with.
Comparison between incus short process and long process coupling of the vibrant soundbridge in human temporal bones
Published in International Journal of Audiology, 2023
Lukas Graf, Jonas Lochner, Hamidreza Mojallal, Andreas Arnold, Flurin Honegger, Christof Stieger
Comparisons of the described differences between SP and LP coupling on the outcome in clinical studies are limited as for our data showing the efficiency of the system. This might have an impact on the battery lifetime and not influence the clinical performance as long as the transducer is driven within its working range. Nevertheless, a higher efficiency could enlarge the indication range. As in a clinical setup, direct comparison of two couplers in the same specimen is impossible. Some studies show no significant difference in terms of word recognition (Lee et al. 2017; Rahne et al. 2021). However, Schraven et al. (2018) found an increased speech perception with SP couplers, what is supported by our findings of a significantly increased efficiency for the SP coupler in speech relevant frequencies.
Diagnostic accuracy of clinically applied nanoparticle-based biosensors at detecting SARS-CoV-2 RNA and surface proteins in pharyngeal swabs compared to RT-PCR as a reference test
Published in Expert Review of Molecular Diagnostics, 2022
Milad Shirvaliloo, Roghayeh Sheervalilou, Ehsan Ahmadpour, Saeid Safiri, Hossein Bannazadeh Baghi
In short, a biosensor is a device consisting of bioreceptors (e.g. antibody, DNA, protein receptors, etc.) and transducers, and is considered the backbone of biosensing platforms that are commonly used for detection of various molecules such as infective agents and disease-specific biomarkers. The transducer is an integrated part of any biosensor and is responsible for converting a biological response; for instance, the presence of SARS-CoV-2 particles in a patient sample, to electrical, optical, fluorescent or any other type of signal that can be measured visually. Nanobiosensors or nanosensors are, in effect, biosensors with integrated nanomaterials. These nanomaterials include a very extensive range of nanocomposites like nanotubes (NTs), nanorods (NRs), nanowires (NWs) and nanoparticles (NPs), the latter of which have garnered widespread attention, owing to their high carrier capacity and stability [4].
Biosensors for the detection of mycotoxins
Published in Toxin Reviews, 2022
Akansha Shrivastava, Rakesh Kumar Sharma
A biosensor can be defined as any measuring device containing a compound of biological origin and used as a sensing bio-recognition element that is closely associated with a sensor element (physicochemical transducer). Whole microbial cell, antibody, enzyme, protein, and nucleic acid are the most frequently used bio-recognition element. The physicochemical transducer can be electrochemical, optical, piezoelectric optical, and sometimes thermal (Pohanka et al. 2007, Nawaz et al. 2017). A biological recognition element is carefully chosen and immobilized within the biosensor. It must be capable of binding the analyte, which needs to be detected and quantify. During the process, the interaction of target and biorecognition element generates a physicochemical signal eased by the transducer, which is finally interpretable by a read-out device to the user. Fabrication of the biosensor is the most important part of the bio-component. The overall performance of the device depends on factors such as chemical, physical conditions, thickness, and stability of materials used. This process permits sensitive detection of mycotoxins (Evtugyn et al. 2017) (Table 1).