Design and characterization of a PVDF ultrasonic range sensor

An ultrasonic sensor for in-air applications has been fabricated using ferroelectric polymer technology. The proximity sensor, designed to be incorporated into a multiple sensing robotic gripper, consists of two unimodal transducers, a transmitter, and a receiver and is obtained by curving a strip of 40-mum-thick polyvinylidene fluoride. The transducers have a resonance frequency of 63.5 kHz, a quality factor Q approximately equal to 12 and a transverse piezoelectric coupling coefficient k(31) of 0.29. The maximum detectable distance is 300 mm, with an axial resolution of about 3 mm. Furthermore transducers resonating at 380 kHz, which operate at a maximum distance of 100 mm with a resolution of 2 mm can be fabricated by using the same technique. Features and performance of both transmitter and receiver are discussed, together with the echo acquisition and the preprocessing electronic unit.     

Quantifying the Detrimental Effects of Multiple Freeze/Thaw Cycles on Primary Human Lymphocyte Survival and Function

The use of cryopreserved peripheral blood mononuclear cells is common in biological research. It is widely accepted that primary cells are rendered unusable by several freezing cycles, although this practice might be very helpful when the biological material is valuable and its re-collection is impractical. To determine the extent to which primary cells undergoing repeated freezing cycles are comparable to one another and to fresh samples, we evaluated overall lymphocyte viability, their proliferation and cytokine production capabilities, as well as the levels of 27 cell subtypes in ten human peripheral blood mononuclear cells frozen for five years and repeatedly thawed. As expected, we observed a progressive increase in cell death percentages on three rounds of thawing, but the frequency of the main lymphocyte subsets was stable across the three thawings. Nevertheless, we observed a significant reduction of B cell frequency in frozen samples compared to fresh ones. On repeated thawings and subsequent conventional stimulation, lymphocyte proliferation significantly decreased, and IL-10, IL-6, GM-CSF, IFN-gamma, and IL-8 showed a trend to lower values.     

Complexity‐reduced in the hydroclimatological modelling of aquifer's discharge

Climate variability induces considerable interannual fluctuations in spring discharge, especially in mountain areas, where groundwater is recharged mainly by rain and snow melt. This study presents the discharge climatological model (DISCLIM), which was developed to test a complexity‐reduced approach to perform historical reconstruction in the lack of physical assumptions. The Mount Cervialto aquifer (Southern Italy) is the test site, where a powerful karst spring is monitored since the 1920s and is very sensitive to climatic conditions. DISCLIM incorporates seasonal precipitation and climate indicators only. Despite its simplicity, DISCLIM has been able to well estimate the yearly fluctuations of discharge hydrological, explaining about 90% of the interannual variability at the calibration stage, and more than 80% at validation stage. This means that DISCLIM can be easily used for estimating the discharge in historical times, when no all the hydrological balance data are available for the purpose.     

CD8+ T Cell Senescence: Lights and Shadows in Viral Infections,Autoimmune Disorders and Cancer

CD8⁺ T lymphocytes are a heterogeneous class of cells that play a crucial role in the adaptive immune response against pathogens and cancer. During their lifetime, they acquire cytotoxic functions to ensure the clearance of infected or transformed cells and, in addition, they turn into memory lymphocytes, thus providing a long-term protection. During ageing, the thymic involution causes a reduction of circulating T cells and an enrichment of memory cells, partially explaining the lowering of the response towards novel antigens with implications in vaccine efficacy. Moreover, the persistent stimulation by several antigens throughout life favors the switching of CD8⁺ T cells towards a senescent phenotype contributing to a low-grade inflammation that is a major component of several ageing-related diseases. In genetically predisposed young people, an immunological stress caused by viral infections (e.g., HIV, CMV, SARS-CoV-2), autoimmune disorders or tumor microenvironment (TME) could mimic the ageing status with the consequent acceleration of T cell senescence. This, in turn, exacerbates the inflamed conditions with dramatic effects on the clinical progression of the disease. A better characterization of the phenotype as well as the functions of senescent CD8⁺ T cells can be pivotal to prevent age-related diseases, to improve vaccine strategies and, possibly, immunotherapies in autoimmune diseases and cancer.     

A piezoresistive tactile sensor

A piezoresistive strain-gauge sensor, mounted in an array configuration, for the measurement of distributed pressures during robotic grasp applications is investigated. The prototype presented consists of a 16-element test cell connected to an electronic acquisition unit that also provides temperature compensation. The structure of the tactile sensor and its principle of operation are described     

The effect of surface on the power spectrum of the Barkhausen noise in ferromagnetic materials

The Barkhausen noise power spectrum was investigated on laminated polycrystalline toroids of Fe and 4% SiFe as a function of sample thickness; that is, of surface-to-volume ratio. Upon decreasing the thickness strong variations of spectrum shape are observed-the cut-off frequency increases and the spectral density drops in the very-low-frequency range. On the other hand, only negligible variations of static magnetic properties are observed. According to a recent theory, the results are explained assuming that a change of thickness directly affects the number of elementary pulses clustering into a large Barkhausen discontinuity. The calculated variations of the spectrum intensity and cut-off frequency are in good agreement with the experimental results.     

The Impact of the ‘Mis-Peptidome’ on HLA Class I-Mediated Diseases: Contribution of ERAP1 and ERAP2 and Effects on the Immune Response

The strong association with the Major Histocompatibility Complex (MHC) class I genes represents a shared trait for a group of autoimmune/autoinflammatory disorders having in common immunopathogenetic basis as well as clinical features. Accordingly, the main risk factors for Ankylosing Spondylitis (AS), prototype of the Spondyloarthropathies (SpA), the Behçet’s disease (BD), the Psoriasis (Ps) and the Birdshot Chorioretinopathy (BSCR) are HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02, respectively. Despite the strength of the association, the HLA pathogenetic role in these diseases is far from being thoroughly understood. Furthermore, Genome-Wide Association Studies (GWAS) have highlighted other important susceptibility factors such as Endoplasmic Reticulum Aminopeptidase (ERAP) 1 and, less frequently, ERAP2 that refine the peptidome presented by HLA class I molecules to CD8⁺ T cells. Mass spectrometry analysis provided considerable knowledge of HLA-B*27, HLA-B*51, HLA-C*06:02 and HLA-A*29:02 immunopeptidome. However, the combined effect of several ERAP1 and ERAP2 allelic variants could generate an altered pool of peptides accounting for the “mis-immunopeptidome” that ranges from suboptimal to pathogenetic/harmful peptides able to induce non-canonical or autoreactive CD8⁺ T responses, activation of NK cells and/or garbling the classical functions of the HLA class I molecules. This review will focus on this class of epitopes as possible elicitors of atypical/harmful immune responses which can contribute to the pathogenesis of chronic inflammatory diseases.     

Computed tomography in injuries to the respiratory system in children. The correlation with adults

INTRODUCTION: Diagnostic imaging in emergency rooms may be inadequate and delayed, which makes chest traumas in children more severe and difficult to treat. We carried out a retrospective study on adults and children who had survived major chest traumas involving the respiratory tract to assess the differences between the two age groups and the role of emergency CT. MATERIAL AND METHODS: Our series consisted of fourteen children admitted to the emergency department for various accidents. Home accidents prevailed (9/14 = 64.3%). On admission, chest radiography was performed in most cases (11/14 = 78.6%); CT was carried out in 21.4% (3/14 patients). RESULTS: Trauma involved more organs in pediatric patients (11/14 = 78.6%) and lung involvement was always associated with other types of injury, namely contusion (14/14 = 100%), pneumothorax (11/14 = 78.6%), hemothorax (10/14 = 71.4%), tear (4/14 = 28.6%). CT corrected or integrated the radiographic findings of contusion focus in 67% (8/14) and that of pneumothorax in 63.6%; both patterns cannot be demonstrated otherwise. DISCUSSION: Mixed and multiple posterior parenchymal injuries with no rib fractures prevail in young subjects because their bones and ligaments are more elastic, which may lead to trauma underestimation. Tracheobronchial ruptures and pneumomediastinum are much more severe in children than in adults. Chest plain film is often the only diagnostic tool used, despite its major technical and interpretative limitations, also because skull and abdomen are the most investigated regions. Executive limitations are stronger in childhood, increasing the margin of error and the risk of delayed treatment. CT is as cost-effective as radiography and shows even the injuries missed or poorly depicted on conventional images; CT also gives accurate information on damage severity and nature. CONCLUSIONS: Traumatic injuries are more severe in pediatric patients due to their build and to biomechanical, clinical and management factors. Spiral CT should be considered the examination of choice to be performed in the emergency department equipped also for pediatric re-animation.     

The naturally occurring polymorphism Asp116-->His116, differentiating the ankylosing spondylitis-associated HLA-B*2705 from the non-associated HLA-B*2709 subtype, influences peptide-specific CD8 T cell recognition

HLA-B27 molecules are interesting because of their strong association with ankylosing spondylitis (AS) and reactive arthritis (ReA). A pathogenetic role for these molecules has been postulated in presenting a putative "arthritogenic" peptide to CD8 T cells. The HLA-B*2709 subtype, although differing by a single amino acid (His116-->Asp116) from the widespread and strongly AS-associated subtype HLA-B*2705, is not found in patients. Since residue 116 interacts with the C terminus of the peptide, it is possible that the two subtypes differ in their antigen-presenting features. We show here that CD8 T cells can distinguish the two HLA-B27 subtypes when presenting a same epitope derived from Epstein-Barr virus-latent membrane protein 2. Moreover, alanine scanning mutagenesis analysis revealed that the peptide residues relevant for such recognition are different depending on whether HLA-B*2705 or -B*2709 molecules present the epitope. These results give support to the belief that functional differences determined by subtype-specific polymorphisms can have a pathogenetic relevance and open up a new scenario where subtle modifications within the peptide/HLA ligand might be responsible for the differential association between HLA-B27 subtypes and spondyloarthropathies.