Magnetorheological elastomers characterization under shear loading up to failure: A magneto-mechanical multivariate analysis

This work analyses the shear behavior of magnetorheological elastomers (MRE), a class of smart materials which presents interesting magneto-mechanical properties. In order to determine the effect of several variables at a time, a design of experiment approach is adopted. A set of several samples of MRE was manufactured, by varying the weight fraction of ferromagnetic material inside the viscoelastic matrix and the isotropicity of the material, by adding an external magnetic field while the elastomeric matrix was still liquid. The mechanical behavior of each sample was analyzed by conducting cyclic tests at several shear rates, both with and without an external magnetic field. Moreover, in order to estimate the maximum shear stress, the specimens were loaded monotonically up to failure. Shear stiffness, maximum shear stress and specific dissipated energy were calculated on the basis of the experimental data. The results were analyzed using an Analysis of Variance (ANOVA) to assess the statistical influence of each variable. The experimental results highlighted a strong correlation between the weight fraction of ferromagnetic material in each sample and its mechanical behavior. Moreover, the dissipated energy of the MRE drops down when the magnetic field stiffens the behavior or the shear rate increases. The ultimate failure shear stress is strongly affected by the external magnetic field, increasing it by nearly 50%. The ANOVA on the results provides a simple phenomenological model is built for each output variable and it is compared with the experimental tests. These models produce a fast and fairly accurate prediction of each analyzed response of the MRE under various shear rates and applied magnetic fields

Transient spectroscopy of the reaction of cyanide with ferrous myoglobin: Effect of distal side residues

The reaction of cyanide metmyoglobin with dithionite conforms to a two-step sequential mechanism with formation of an unstable intermediate, identified as cyanide bound ferrous myoglobin. This reaction was investigated by stopped-flow time resolved spectroscopy using different myoglobins, i.e. those from horse heart, Aplysia limacina buccal muscle, and three recombinant derivatives of sperm whale skeletal muscle myoglobin (Mb) (the wild type and two mutants). The myoglobins from horse and sperm whale (wild type) have in the distal position (E7) a histidyl residue, which is missing in A. limacina Mb as well as the two sperm whale mutants (E7 His----Gly and E7 His----Val). All these proteins in the reduced form display an extremely low affinity for cyanide at pH less than 10. The differences in spectroscopy and kinetics of the ferrous cyanide complex of these myoglobins indicate a role of the distal pocket on the properties of the complex. The two mutants of sperm whale Mb are characterized by a rate constant for the decay of the unstable intermediate much faster than that of the wild type, at all pH values explored. Therefore, we envisage a specific role of the distal His (E7) in controlling the rate of cyanide dissociation and also find that this effect depends on the protonation of a single ionizable group, with pK = 7.2, attributed to the E7 imidazole ring. The results on A. limacina Mb, which displays the slowest rate of cyanide dissociation, suggests that a considerable stabilizing effect can be exerted by Arg E10 which, according to Bolognesi et al. (Bolognesi, M., Coda, A., Frigerio, F., Gatti, C., Ascenzi, P., and Brunori, M. (1990) J. Mol. Biol. 213, 621-625), interacts inside the pocket with fluoride bound to the ferric heme iron. A mechanism of control for the rate of dissociation of cyanide from ferrous myoglobin, involving protonation of the bound anion, is discussed

Exploring depression in Parkinson's disease: an Italian Delphi Consensus on phenomenology, diagnosis, and management

Background: Depression is a prodromic and a frequent non-motor symptom of Parkinson's disease, associated to reduced quality of life and poor outcomes. The diagnosis of depression in parkinsonian patients represents a challenge due to the overlapping of symptoms typical of the two conditions. Methods: A Delphi panel survey was performed to reach a consensus amongst different Italian specialists on four main topics: the neuropathological correlates of depression, main clinical aspects, diagnosis, and management of depression in Parkinson's disease. Results and conclusion: Experts have recognized that depression is an established risk factor of PD and that its anatomic substrate is related to the neuropathological abnormalities typical of the disease. Multimodal and SSRI antidepressant have been confirmed as a valid therapeutic option in the treatment of depression in PD. Tolerability, safety profile, and potential efficacy on broad spectrum of symptoms of depression including cognitive symptoms and anhedonia should be considered when selecting an antidepressant and the choice should be tailored on the patients' characteristics

Fragment-based discovery of a regulatory site in thioredoxin glutathione reductase acting as "doorstop" for NADPH entry

Members of the FAD/NAD-linked reductase family are recognized as crucial targets in drug development for cancers, inflammatory disorders, and infectious diseases. However, individual FAD/NAD reductases are difficult to inhibit in a selective manner with off target inhibition reducing usefulness of identified compounds. Thioredoxin glutathione reductase (TGR), a high molecular weight thioredoxin reductase-like enzyme, has emerged as a promising drug target for the treatment of schistosomiasis, a parasitosis afflicting more than 200 million people. Taking advantage of small molecules selected from a high-throughput screen and using X-ray crystallography, functional assays, and docking studies, we identify a critical secondary site of the enzyme. Compounds binding at this site interfere with well-known and conserved conformational changes associated with NADPH reduction, acting as a doorstop for cofactor entry. They selectivity inhibit TGR from Schistosoma mansoni and are active against parasites in culture. Since many members of the FAD/NAD-linked reductase family have similar catalytic mechanisms the unique mechanism of inhibition identified in this study for TGR broadly opens new routes to selectively inhibit homologous enzymes of central importance in numerous diseases

Detecting delirium superimposed on dementia: diagnostic accuracy of a simple combined arousal and attention testing procedure

Detecting delirium superimposed on dementia (DSD) can be challenging because assessment partly relies on cognitive tests that may be abnormal in both conditions. We hypothesized that a combined arousal and attention testing procedure would accurately detect DSD. Patients aged ≥70 years were recruited from five hospitals across Europe. Delirium was diagnosed by physicians using DSM-5 criteria using information from nurses, carers, and medical records. Dementia was ascertained by the Informant Questionnaire on Cognitive Decline in the Elderly. Arousal was measured using the Observational Scale of Level of Arousal (OSLA), which assesses eye opening, eye contact, posture, movement, and communication. Attention was measured by participants signaling each time an “A” was heard when “S-A-V-E-A-H-A-A-R-T” was read out. The sample included 114 persons (mean age 82 years (SD 7); 54% women). Dementia alone was present in 25% (n = 28), delirium alone in 18% (n = 21), DSD in 27% (n = 31), and neither in 30% (n = 34). Arousal and attention was assessed in n = 109 (96%). Using OSLA, 83% participants were correctly identified as having delirium (sensitivity 85%, specificity 82%, AUROC 0.92). The attention task correctly classified 76% of participants with delirium (sensitivity 90%, specificity 64%, AUROC 0.80). Combining scores correctly classified 91% of participants with delirium (sensitivity 84%, specificity 92%, AUROC 0.94). Diagnostic accuracy remained high in the subgroup with dementia (93% correctly classified, sensitivity 94%, specificity 92%, AUROC 0.98). This combined arousal–attention assessment to detect DSD was brief yet had high diagnostic accuracy. Such an approach could have clinical utility for diagnosing DSD

Systematic review of the literature on the clinical effectiveness of the cochlear implant procedure in paediatric patients

The aim of this systematic review of the literature was to summarize the results of scientific publications on the clinical effectiveness of the cochlear implant (CI) procedure in children. The members of the Working Group first examined existing national and international literature and the principal international guidelines on the procedure. They considered as universally-accepted the usefulness/effectiveness of unilateral cochlear implantation in severely-profoundly deaf children. Accordingly, they focused attention on systematic reviews addressing clinical effectiveness and cost/efficacy of the CI procedure, with particular regard to the most controversial issues for which international consensus is lacking. The following aspects were evaluated: post-CI outcomes linked to precocity of CI; bilateral (simultaneous/ sequential) CI vs. unilateral CI and vs. bimodal stimulation; benefits derived from CI in deaf children with associated disabilities. With regard to the outcomes after implantation linked to precocity of intervention, there are few studies comparing post-CI outcomes in children implanted within the first year of life with those of children implanted in the second year. The selected studies suggest that children implanted within the first year of life present hearing and communicative outcomes that are better than those of children implanted after 12 months of age. Concerning children implanted after the first year of life, all studies confirm an advantage with respect to implant precocity, and many document an advantage in children who received cochlear implants under 18 months of age compared to those implanted at a later stage. With regard to bilateral CI, the studies demonstrate that compared to unilateral CI, bilateral CI offers advantages in terms of hearing in noise, sound localization and during hearing in a silent environment. There is, however, a wide range of variability. The studies also document the advantages after sequential bilateral CI. In these cases, a short interval between interventions, precocity of the first CI and precocity of the second CI are considered positive prognostic factors. In deaf children with associated disabilities, the studies analyzed evidence that the CI procedure is also suitable for children with disabilities associated with deafness, and that even these children may benefit from the procedure, even if these may be slower and inferior to those in children with isolated deafness, especially in terms of high communicative and perceptive skills

Residential proximity to petrol stations and risk of childhood leukemia

Petrol stations emit benzene and other contaminants that have been associated with an increased risk of childhood leukemia. We carried out a population-based case-control study in two provinces in Northern Italy. We enrolled 182 cases of childhood leukemia diagnosed during 1998-2019 and 726 age- and sex-matched population controls. We geocoded the addresses of child residences and 790 petrol stations located in the study area. We estimated leukemia risk according to distance from petrol stations within a 1000 m buffer and amount of supplied fuel within a buffer of 250 m from the child's residence. We used conditional logistic regression models to approximate risk ratios (RRs) and 95% confidence intervals (CIs) for associations of interest, adjusted for potential confounders. We also modeled non-linear associations using restricted cubic splines. In secondary analyses, we restricted to acute lymphoblastic leukemia (ALL) cases and stratifed by age (<5 and >= 5 years). Compared with children who lived >= 1000 m from a petrol station, the RR was 2.2 (95% CI 0.5-9.4) for children living<50 m from nearest petrol station. Associations were stronger for the ALL subtype (RR=2.9, 95% CI 0.6-13.4) and among older children (age >= 5 years: RR=4.4, 95% CI 0.6-34.1; age<5 years: RR=1.6, 95% CI 0.1-19.4). Risk of leukemia was also greater (RR=1.6, 95% CI 0.7-3.3) among the most exposed participants when assigning exposure categories based on petrol stations located within 250 m of the child's residence and total amount of gasoline delivered by the stations. Overall, residence within close proximity to a petrol station, especially one with more intense refueling activity, was associated with an increased risk of childhood leukemia, though associations were imprecise

Reduced level of arousal and increased mortality in adult acute medical admissions: a systematic review and meta-analysis

Abstract Background Reduced level of arousal is commonly observed in medical admissions and may predict in-hospital mortality. Delirium and reduced level of arousal are closely related. We systematically reviewed and conducted a meta-analysis of studies in adult acute medical patients of the relationship between reduced level of arousal on admission and in-hospital mortality. Methods We conducted a systematic review (PROSPERO: CRD42016022048), searching MEDLINE and EMBASE. We included studies of adult patients admitted with acute medical illness with level of arousal assessed on admission and mortality rates reported. We performed meta-analysis using a random effects model. Results From 23,941 studies we included 21 with 14 included in the meta-analysis. Mean age range was 33.4 - 83.8 years. Studies considered unselected general medical admissions (8 studies, n=13,039) or specific medical conditions (13 studies, n=38,882). Methods of evaluating level of arousal varied. The prevalence of reduced level of arousal was 3.1%-76.9% (median 13.5%). Mortality rates were 1.7%-58% (median 15.9%). Reduced level of arousal was associated with higher in-hospital mortality (pooled OR 5.71; 95% CI 4.21-7.74; low quality evidence: high risk of bias, clinical heterogeneity and possible publication bias). Conclusions Reduced level of arousal on hospital admission may be a strong predictor of in-hospital mortality. Most evidence was of low quality. Reduced level of arousal is highly specific to delirium, better formal detection of hypoactive delirium and implementation of care pathways may improve outcomes. Future studies to assess the impact of interventions on in-hospital mortality should use validated assessments of both level of arousal and delirium