Metal-polymer nanocomposite with stable plasmonic tuning under cyclic strain conditions

We report the fabrication and characterization of stretchable nanocomposite films with mechanically tunable surface plasmon resonance. The films have been produced by implantation in a Polydimethylsiloxane substrate of neutral gold nanoparticles aerodynamically accelerated in a supersonic expansion. Optical absorption spectroscopy shows that uniaxial stretching of the nanocomposite induce a reversible redshift of the plasmon peak up to 180 nm from the peak wavelength of the non-stretched sample. The range of the plasmon peak shift depends upon the density of implanted nanoparticles. The optical behavior of the nanocomposite evolves upon cyclical stretching due to the rearrangement of the nanoparticles in the elastomeric matrix. We have identified the fabrication and post-deposition treatment conditions to stabilize the plasmonic shift upon cyclical stretching in order to obtain robust and large area nanocomposites with tunable and reproducible optical properties over a wide visible wavelength range

Facile fabrication of complex networks of memristive devices

We describe the memristive properties of cluster-assembled gold films. We show that resistive switching is observed in pure metallic nanostructured films at room temperature and atmospheric pressure, in response to applied voltage inputs. In particular, we observe resistance changes up to 400% and archetypal switching events that have remarkable symmetry with the applied voltage. We associated this symmetry with 'potentiation' and 'anti-potentiation' processes involving the activation of synapses and of pathways comprising multiple synapses. The stability and reproducibility of the resistance switching, which lasted over many hours, make these devices ideal test-beds for exploration of the basic mechanisms of the switching processes, and allow convenient fabrication of devices that may have neuromorphic properties

Clinical features and therapeutic management of patients admitted to Italian acute hospital psychiatric units: the PERSEO (psychiatric emergency study and epidemiology) survey

<p>Abstract</p> <p>Background</p> <p>The PERSEO study (psychiatric emergency study and epidemiology) is a naturalistic, observational clinical survey in Italian acute hospital psychiatric units, called SPDCs (Servizio Psichiatrico Diagnosi e Cura; in English, the psychiatric service for diagnosis and management). The aims of this paper are: (i) to describe the epidemiological and clinical characteristics of patients, including sociodemographic features, risk factors, life habits and psychiatric diagnoses; and (ii) to assess the clinical management, subjective wellbeing and attitudes toward medications.</p> <p>Methods</p> <p>A total of 62 SPDCs distributed throughout Italy participated in the study and 2521 patients were enrolled over the 5-month study period.</p> <p>Results</p> <p>Almost half of patients (46%) showed an aggressive behaviour at admission to ward, but they engaged more commonly in verbal aggression (38%), than in aggression toward other people (20%). A total of 78% of patients had a psychiatric diagnosis at admission, most frequently schizophrenia (36%), followed by depression (16%) and personality disorders (14%), and no relevant changes in the diagnoses pattern were observed during hospital stay. Benzodiazepines were the most commonly prescribed drugs, regardless of diagnosis, at all time points. Overall, up to 83% of patients were treated with neuroleptic drugs and up to 27% received more than one neuroleptic either during hospital stay or at discharge. Atypical and conventional antipsychotics were equally prescribed for schizophrenia (59 vs 65% during stay and 59 vs 60% at discharge), while atypical drugs were preferred in schizoaffective psychoses (72 vs 49% during stay and 70 vs 46% at discharge) and depression (41 vs 32% during stay and 44 vs 25% at discharge). Atypical neuroleptics were slightly preferred to conventional ones at hospital discharge (52 vs 44%). Polypharmacy was in general widely used. Patient attitudes toward medications were on average positive and self-reported compliance increased during hospital stay.</p> <p>Conclusion</p> <p>Results confirm the widespread use of antipsychotics and the increasing trend in atypical drugs prescription, in both psychiatric in- and outpatients.</p

A genome-wide association study for survival from a multi-centre European study identified variants associated with COVID-19 risk of death

The clinical manifestations of SARS-CoV-2 infection vary widely among patients, from asymptomatic to life-threatening. Host genetics is one of the factors that contributes to this variability as previously reported by the COVID-19 Host Genetics Initiative (HGI), which identified sixteen loci associated with COVID-19 severity. Herein, we investigated the genetic determinants of COVID-19 mortality, by performing a case-only genome-wide survival analysis, 60&nbsp;days after infection, of 3904 COVID-19 patients from the GEN-COVID and other European series (EGAS00001005304 study of the COVID-19 HGI). Using imputed genotype data, we carried out a survival analysis using the Cox model adjusted for age, age2, sex, series, time of infection, and the first ten principal components. We observed a genome-wide significant (P-value &lt; 5.0 × 10−8) association of the rs117011822 variant, on chromosome 11, of rs7208524 on chromosome 17, approaching the genome-wide threshold (P-value = 5.19 × 10−8). A total of 113 variants were associated with survival at P-value &lt; 1.0 × 10−5 and most of them regulated the expression of genes involved in immune response (e.g., CD300 and KLR genes), or in lung repair and function (e.g., FGF19 and CDH13). Overall, our results suggest that germline variants may modulate COVID-19 risk of death, possibly through the regulation of gene expression in immune response and lung function pathways

Common, low-frequency, rare, and ultra-rare coding variants contribute to COVID-19 severity

The combined impact of common and rare exonic variants in COVID-19 host genetics is currently insufficiently understood. Here, common and rare variants from whole-exome sequencing data of about 4000 SARS-CoV-2-positive individuals were used to define an interpretable machine-learning model for predicting COVID-19 severity. First, variants were converted into separate sets of Boolean features, depending on the absence or the presence of variants in each gene. An ensemble of LASSO logistic regression models was used to identify the most informative Boolean features with respect to the genetic bases of severity. The Boolean features selected by these logistic models were combined into an Integrated PolyGenic Score that offers a synthetic and interpretable index for describing the contribution of host genetics in COVID-19 severity, as demonstrated through testing in several independent cohorts. Selected features belong to ultra-rare, rare, low-frequency, and common variants, including those in linkage disequilibrium with known GWAS loci. Noteworthily, around one quarter of the selected genes are sex-specific. Pathway analysis of the selected genes associated with COVID-19 severity reflected the multi-organ nature of the disease. The proposed model might provide useful information for developing diagnostics and therapeutics, while also being able to guide bedside disease management. © 2021, The Author(s)

Genome-wide Association Study of Long COVID

SummaryInfections can lead to persistent or long-term symptoms and diseases such as shingles after varicella zoster, cancers after human papillomavirus, or rheumatic fever after streptococcal infections1, 2. Similarly, infection by SARS-CoV-2 can result in Long COVID, a condition characterized by symptoms of fatigue and pulmonary and cognitive dysfunction3–5. The biological mechanisms that contribute to the development of Long COVID remain to be clarified. We leveraged the COVID-19 Host Genetics Initiative6, 7to perform a genome-wide association study for Long COVID including up to 6,450 Long COVID cases and 1,093,995 population controls from 24 studies across 16 countries. We identified the first genome-wide significant association for Long COVID at theFOXP4locus.FOXP4has been previously associated with COVID-19 severity6, lung function8, and cancers9, suggesting a broader role for lung function in the pathophysiology of Long COVID. While we identify COVID-19 severity as a causal risk factor for Long COVID, the impact of the genetic risk factor located in theFOXP4locus could not be solely explained by its association to severe COVID-19. Our findings further support the role of pulmonary dysfunction and COVID-19 severity in the development of Long COVID.</jats:p

A very simple scheme for spectrally resolved imaging by means of curved polymeric gratings

We report the fabrication of a simple and inexpensive device based on diffractive optics for spectrally resolved imaging. A brass surface manufactured on a metal lathe and a deformable, reflecting diffraction grating guarantee spatially and spectrally resolved images without the need for other optical elements. The grating is a metal-polymer nanocomposite replica of a plastic grating: reflectivity of the transparent dielectric substrate is obtained by the implantation of gold clusters, hence preserving deformability. The brass surface is a portion of a rotation ellipsoid, on which the deformable grating adheres to gain optical power. According to the optical tests performed on the system, the achieved spatial resolution of the system is ~80 \u3bcm, whereas limiting spectral resolution of about 3 nm is observed. Reflectivity of the zero-order reflection and the first order diffraction approaches 45% and 5% respectively. We detail the results for the reconstruction of an on-axis and off-axis pointlike source, and a vertically extended slit-like source with a 110 \u3bcm obstruction

Shape Changes in AuPd Alloy Nanoparticles Controlled by Anisotropic Surface Stress Relaxation

The shape of AuPd nanoparticles is engineered by surface stress relaxation, achieved by varying the Au content in nanoparticles of Pd-rich compositions. AuPd nanoparticles are grown in the gas phase for several compositions and growth conditions. Their structure is atomically resolved by HRTEM/STEM and EDX. In pure Pd distributions the dominant structures are FCC truncated octahedra (TO), while increasing the Au content there is a transition to icosahedral (Ih) structures in which Au atoms are preferentially placed at the nanoparticle surface. The transition is sharper for growth conditions closer to equilibrium. The physical origin of the transition is determined with the aid of computer simulations. Global optimization searches and free energy calculations confirm that Ih become the equilibrium structure for increasing the Au content. Atomic stress calculations demonstrate that the TO \u2192 Ih shape change is caused by a better relaxation of anisotropic surface stress in icosahedra