A match coefficient approach for damage imaging in structural components by ultrasonic synthetic aperture focus

Ultrasonic Synthetic Aperture Focus (SAF) techniques are commonly used to image structural defects. In this paper, a variation of SAF based on ideas borrowed from Matched Field Processing (MFP) is evaluated to reduce artifacts and sidelobes of the resulting images. In particular, instead of considering the full RF ultrasonic waveforms for the SAF time backpropagation, only selected features from the waveforms are utilized to form a “data vector” and a “replica” (expected) vector of MFP. These vectors are adaptive for the pair of transmitter-receiver and the focus point. The image is created as a matched filter between these two vectors. Experimental results are shown for an isotropic and homogenous metallic plate with simulated defects, probed by six piezoelectric patches used as receivers or transmitters

Methods for preclinical validation of software as a medical device

Software as a medical device is subject to dedicated regulatory requirements before it can be used on human beings. The certification process in Europe requires that sufficient data on clinical benefits are available before the device is CE marked. This position paper describes our proposal of a risk-based approach to technical and preclinical validation of software as medical devices. This approach ensures that all technical solutions for safety are implemented in the software and that all information for safe use is consistent before the software can be made available to patients. This approach is compliant to the main international standards ISO 13485 on quality systems and ISO 14971 on risk management and therefore ensures regulatory compliance as well as patient protection. This integrated approach allows the designers of the software to integrate regulatory and safety testing in the technical testing of the candidate release version of the device. This approach ensures patient safety and regulatory compliance at the same time as technical functionality

A Proposal For COVID-19 Applications Enabling Extensive Epidemiological Studies

During the next phase of COVID-19 outbreak, mobile applications could be the most used and proposed technical solution for monitoring and tracking, by acquiring data from subgroups of the population. A possible problem could be data fragmentation, which could lead to three harmful effects: i) data could not cover the minimum percentage of the people for monitoring efficacy, ii) it could be heavily biased due to different data collection policies, and iii) the app could not monitor subjects moving across different zones or countries. A common approach could solve these problems, defining requirements for the selection of observed data and technical specifications for the complete interoperability between different solutions. This work aims to integrate the international framework of requirements in order to mitigate the known issues and to suggest a method for clinical data collection that ensures to researchers and public health institution significant and reliable data. First, we propose to identify which data is relevant for COVID-19 monitoring through literature and guidelines review. Then we analysed how the currently available guidelines for COVID-19 monitoring applications drafted by European Union and World Health Organization face the issues listed before. Eventually we proposed the first draft of integration of current guidelines

A novel method for validating multi-classifiers. A case study for ICF-based health status classification

In this paper, we propose a novel method for the validation of a multi-classification model according to the intended use and aim of a device for health status classification and the clinical needs of the practitioners involved

Usability assessment of an intraoperative planning software

Usability is a crucial aspect of medical device safety. The brand-new European Regulation requires the manufacturer to assess the usability of the new medical devices. In this study, we evaluate the usability of a new medical device intended to assist the intraoperative planning with the visualization of 3d patient-specific organ models. The usability study started from the early stage of the device design and iterated through an early formative, completed with desk-based activities, late formative, completed with a focus group, and summative phase, that comprised a user test, and questionnaire filling. The identified usability issues are mitigated, the safety of the device user interface is confirmed and the training contents are defined and confirmed. Additional information regarding the user experience is collected and analyzed to identify further improvements of the device

Peptidergic receptors

The term neuropeptides refers to a relatively large number of biologically active molecules localized to discrete cell populations of nervous system, including autonomic ganglion neurons and their effector cells. Different combinations of transmitters and peptides are found in ganglionic cells of the autonomic system which comprise a functional “chemical code” for neurons subserving specific actions. Generally, peptidergic receptors are G-protein coupled receptors acting through multiple transduction pathways which reflect the pleiotropic actions of peptides. This section represents a current view of the most important actions of peptides and their receptors in the autonomic nervous system and in peripheral organs.L'articolo è disponibile sul sito dell'editore http://www.sciencedirect.com

Distribution of α-transducin and α-gustducin immunoreactive cells in the chicken (Gallus domesticus) gastrointestinal tract

The expression and distribution patterns of the taste signaling molecules, α-gustducin (Gαgust) and α-transducin (Gαtran) G-protein subunits, were studied in the gastrointestinal tract of the chicken (Gallus domesticus) using the immunohistochemical method. Gαgust and Gαtran immunoreactive (-IR) cells were observed in the mucosal layer of all examined segments, except the esophagus, crop, and the saccus cranialis of the gizzard. The highest numbers of Gαgust and Gαtran-IR cells were found in the proventriculus glands and along the villi of the pyloric, duodenum, and rectal mucosa. Gαgust and Gαtran-IR cells located in the villi of the jejunum, ileum, and cloaca were much less numerous, while only a few Gαgust and Gαtran-IR cells were detected in the mucosa of the proventriculus and cecum. In the crypts, IR cells were observed in the small and large intestine as well as in the cloaca. Gαgust and Gαtran-IR cells displayed elongated ("bottle-" or "pear-like") or rounded shape. The demonstration of Gαgust and Gαtran expression provides evidence for taste receptor mediated mucosal chemosensitivity in the chicken gastrointestinal tract

Novel understanding on genetic mechanisms of enteric neuropathies leading to severe gut dysmotility

The enteric nervous system (ENS) is the third division of the autonomic autonomic nervous system and the largest collection of neurons outside the central nervous system (CNS). The ENS has been referred to as "the brain in the gut" or "the second brain of the human body" because of its highly integrated neural circuits controlling a vast repertoire of gut functions, including absorption/secretion, splanchnic blood vessels, some immunological aspects, intestinal epithelial barrier, and gastrointestinal (GI) motility. The latter function is the result of the ENS fine-tuning over smooth musculature, along with the contribution of other key cells, such as enteric glia (astrocyte like cells supporting and contributing to neuronal activity), interstitial cells of Cajal (the pacemaker cells of the GI tract involved in neuromuscular transmission), and enteroendocrine cells (releasing bioactive substances, which affect gut physiology). Any noxa insult perturbing the ENS complexity may determine a neuropathy with variable degree of neuro-muscular dysfunction. In this review, we aim to cover the most recent update on genetic mechanisms leading to enteric neuropathies ranging from Hirschsprung's disease (characterized by lack of any enteric neurons in the gut wall) up to more generalized form of dysmotility such as chronic intestinal pseudo-obstruction (CIPO) with a significant reduction of enteric neurons. In this line, we will discuss the role of the RAD21 mutation, which we have demonstrated in a family whose affected members exhibited severe gut dysmotility. Other genes contributing to gut motility abnormalities will also be presented. In conclusion, the knowledge on the molecular mechanisms involved in enteric neuropathy may unveil strategies to better manage patients with neurogenic gut dysmotility and pave the way to targeted therapies

Expression and regulation of α-transducin in the pig gastrointestinal tract

Taste signalling molecules are found in the gastrointestinal (GI) tract suggesting that they participate to chemosensing. We tested whether fasting and refeeding affect the expression of the taste signalling molecule, a-transducin (Gatran), throughout the pig GI tract and the peptide content of Gatran cells. The highest density of Gatran-immunoreactive (IR) cells was in the pylorus, followed by the cardiac mucosa, duodenum, rectum, descending colon, jejunum, caecum, ascending colon and ileum. Most Gatran-IR cells contained chromogranin A. In the stomach, many Gatran-IR cells contained ghrelin, whereas in the upper small intestine many were gastrin/cholecystokinin-IR and a few somatostatin-IR. Gatran-IR and Gagust-IR colocalized in some cells. Fasting (24 h) resulted in a significant decrease in Gatran-IR cells in the cardiac mucosa (29.3 0.8 versus 64.8 1.3, P < 0.05), pylorus (98.8 1.7 versus 190.8 1.9, P < 0.0 l), caecum (8 0.01 versus 15.5 0.5, P < 0.01), descending colon (17.8 0.3 versus 23 0.6, P < 0.05) and rectum (15.3 0.3 versus 27.5 0.7, P < 0.05). Refeeding restored the control level of Gatran-IR cells in the cardiac mucosa. In contrast, in the duodenum and jejunum, Gatran-IR cells were significantly reduced after refeeding, whereas Gatran-IR cells density in the ileum was not changed by fasting/refeeding. These findings provide further support to the concept that taste receptors contribute to luminal chemosensing in the GI tract and suggest they are involved in modulation of food intake and GI function induced by feeding and fasting