169,947 research outputs found
Mechanical-optical-electro modulation by stretching a polymer-metal nanocomposite
No full textWe report the simultaneous investigation of both the plasmonic resonance and electrical conductance evolution in stretchable metal-polymer nanocomposite films. The films are produced by the implantation of neutral gold nanoparticles in a polydimethylsiloxane substrate by aerodynamic acceleration in a supersonic expansion. A redshift of the gold nanoparticle plasmon peak is found upon stretching as well as a strong correlation between the plasmonic peak wavelength and the nanocomposite electrical resistance. Optical simulations attribute the optical response to the compression of the polymer perpendicular to the stretching direction, which brings the gold particles closer to each other, increasing the plasmonic coupling. Mechanical stretching can induce a simultaneous modulation of the optical and electrical properties of the nanocomposite
Pneumococcal polysaccharide immunization strategies in Italian regions
No full textThe aim of this study is to describe the immunization strategies for 23-valent pneumococcal vaccine in the Italian regions. Sixteen regions offer pneumococcal vaccine to elderly people and 18 regions to risk groups. Nine among them offer the vaccine free of charge and perform the call for immunization. Five regions created a database of the risk groups. Data about vaccination coverage are available for seven regions; in the other only the number of administered doses is collected yearly. Different immunization strategies may represent a determinant of health inequalities
Synthesis of a 4-Vinyltetrahydrocarbazole by Palladium-Catalyzed Asymmetric Allylic Alkylation of Indole-Containing Allylic Carbonates
No full textPalladium-catalyzed intramolecular asymmetric allylic alkylation was used for the first time to prepare 4-vinyltetrahydrocarbazole 3. Suitable indole-containing allylic carbonates were synthesized and cyclized in the presence of a chiral catalyst formed in situ from Pd(OAc)2 and members of the PhthalaPhos ligand library (i.e., 1,1′-bi-2-naphthol-monophosphites possessing a phthalic acid diamide group). The use of a stable and readily available palladium source such as Pd(OAc)2 reduced in situ by the phosphite to form the Pd0 catalyst allowed better and more reproducible results to be obtained relative to the results achieved by using [Pd2(dba)3·CHCl3] (dba = dibenzylideneacetone) and [Pd(allyl)Cl]2. A ligand screening led to identification of the best ligand [(S)-L1], which, after optimization of the reaction parameters, gave product 3 with 75 % ee. Remarkably, the reaction turned out to be stereodivergent: by using ligand (S)-L1, the absolute configuration of product 3 was found to depend on the geometry of the substrate's double bond [(E)-substrate → (S)-3, (Z)-substrate → (R)-3]
An audit about clinical governance skills in Italian medical managers
No full textThe objective of this study is to describe the knowledge and skills of managers working in health organizations in the Region of Puglia (South of Italy) on the principles and tools of clinical governance
Developing a Reciprocating Mechanism for the Emergency Implementation of a Mechanical Pulmonary Ventilator using an Integrated CAD-MBD Procedure
No full textFollowing the COVID-19 outbreak, the redesign of an emergency mechanical pulmonary ventilator that is cheap and easily portable became necessary in several contexts, such as emergency hotspots and environments with poor resources. To address this important issue, a general multibody approach is employed in this paper to develop a reciprocating mechanism suitable for retrofitting the existing manual mechanical ventilators through computer-aided engineering tools. By analyzing various basic articulated mechanisms typically found in engineering mechanics, a prototype is created and reproduced in a threedimensional environment using SOLIDWORKS's CAD software. Subsequently, a high-fidelity mechanical model is developed starting from the CAD geometry and employing the SIMSCAPE MULTIBODY software, an extension of the MATLAB family of programs that can effectively and efficiently perform kinematic and dynamic simulations of the mechanism of interest. As discussed in the paper, by carrying out numerous numerical experiments, the virtual simulations predict several fundamental medical parameters, such as the airflow introduced into patients, the respiratory rate, and the respiratory ratio
Synthesis of a 4-Vinyltetrahydrocarbazole by palladium-catalyzed asymmetric allylic alkylation of indole-containing allylic carbonates
No full textPalladium-catalyzed intramolecular asymmetric allylic alkylation was used for the first time to prepare 4-vinyltetrahydrocarbazole 3. Suitable indole-containing allylic carbonates were synthesized and cyclized in the presence of a chiral catalyst formed in situ from Pd(OAc)2 and members of the PhthalaPhos ligand library (i.e., 1,1′-bi-2-naphthol-monophosphites possessing a phthalic acid diamide group). The use of a stable and readily available palladium source such as Pd(OAc)2―reduced in situ by the phosphite to form the Pd0 catalyst―allowed better and more reproducible results to be obtained relative to the results achieved by using [Pd2(dba)3·CHCl3] (dba = dibenzylideneacetone) and [Pd(allyl)Cl]2. A ligand screening led to identification of the best ligand [(S)-L1], which, after optimization of the reaction parameters, gave product 3 with 75 % ee. Remarkably, the reaction turned out to be stereodivergent: by using ligand (S)-L1, the absolute configuration of product 3 was found to depend on the geometry of the substrate's double bond [(E)-substrate [RIGHTWARDS ARROW] (S)-3, (Z)-substrate [RIGHTWARDS ARROW] (R)-3]
Development Languages and Environments for Induction Cooking System Design and Simulation
No full textOctahedral Growth of PtPd Nanocrystals
No full textPtPd nanoparticles are among the most widely studied nanoscale systems, mainly because of their applications as catalysts in chemical reactions. In this work, a combined experimental-theoretical study is presented about the dependence of growth shape of PtPd alloy nanocrystals on their composition. The particles are grown in the gas phase and characterized by STEM-HRTEM. PtPd nanoalloys present a bimodal size distribution. The size of the larger population can be tuned between 3.8 ± 0.4 and 14.1 ± 2.0 nm by controlling the deposition parameters. A strong dependence of the particle shape on the composition is found: Pd-rich nanocrystals present more rounded shapes whereas Pt-rich ones exhibit sharp tips. Molecular dynamics simulations and excess energy calculations show that the growth structures are out of equilibrium. The growth simulations are able to follow the growth shape evolution and growth pathways at the atomic level, reproducing the structures in good agreement with the experimental results. Finally the optical absorption properties are calculated for PtPd nanoalloys of the same shapes and sizes grown in our experiments
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A computerized photographic method to evaluate changes in head posture and scapular position following rapid palatal expansion: a pilot study
No full textObjective: to assess the applicability of a computerized method to measure on digital photographs the changes in head and scapular posture following rapid palatal expansion (RPE) treatment. Study design: randomized controlled trial. Twenty-three children (age 9.27±0.88 years) diagnosed with maxillary constriction were randomly divided into two groups: 1. Study group (n=12): patients receiving RPE treatment; 2. Untreated controls (n=11). Postural measurements were taken on frontal, lateral, and dorsal views of each subject. In the study group measurements were taken at T0 (the day orthodontic records were taken), T1 (end of RPE active phase), and T2 (RPE removal). In controls the same observations were conducted at T0 and T1(98.18±36.01 days after T0). Measurements were statistically analyzed (Intraclass Correlation Coefficient, t-tests, Signed Rank test, One-Way Repeated Measures Analysis of Variance, Tukey test; p<0.05). Results: In the study group a significant reduction in forward head posture (FHP) occurred between T0 and T1. Forward shoulder posture (FSP) decreased significantly between T1 and T2. At T1 treated patients exhibited significantly lower values of the measurements indicating FHP and FSP than controls. Conclusion: Changes in head and scapular posture following RPE treatment can be documented with computerized measurements on digital photographs
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