Novel PBAT‐Based Biocomposites Reinforced with Bioresorbable Phosphate Glass Microparticles

Biocomposites based on poly(butylene adipate terephthalate) (PBAT) and reinforced with micro-particles of inorganic biodegradable phosphate glass (PG) at 2, 10, and 40 wt% are prepared and characterized from a mechanical and morphological point of view. Scanning electron microscope (SEM) images show a good dispersion of the PG micro-grains, even at high concentrations, in the PBAT matrix, resulting in homogeneous composites. Tensile and dynamic-mechanical tests, respectively, indicate that Young’s and storage moduli increase with PG concentration. The reinforcement of PBAT aims at modifying and tailoring the mechanical and viscoelastic properties of the material to expand its application field especially in the food and agricultural packaging sector, thanks to the similarity of PBAT performance with polyethylene

Preparation and characterization of innovative poly(butylene adipate terephthalate)-based biocomposites for agri-food packaging application

The present work reports on the preparation and subsequent mechanical, morphological and thermal characterization of composites based on poly(butylene adipate terephthalate) (PBAT), reinforced with micro-particles of inorganic bioabsorbable calcium-phosphate glass (CPG) at different contents up to 40 wt%. The PBAT-CPG composites were prepared by solvent casting. The resulting composite pellets were used for the injection molding of model 1BA specimens, according to standard UNI EN ISO 527. PBAT-CPG composites displayed an effective increase of the Young's modulus (E) up to 82% with respect to the pristine polymer, while showing a reduction of the yield stress (σy) up to 20%, of the stress at break (σB) up to 46%, of the strain at break (εB) up to 57% and of the toughness (T) up to 72%. The values of E, σy and σB were also compared and validated with theoretical values calculated using Kerner’s and Pukanszky’s models. Scanning electron microscopy (SEM) images display homogeneous dispersion and distribution of the filler particles in the polymer matrix with no aggregates or phase separation that would cause a deterioration of the material properties. Infrared (IR) spectroscopy did not show structural variations of the polymer matrix due to the CPG presence. The oxygen permeability in PBAT-based samples assumes significantly lower values when benchmarked with the permeability of low-density polyethylene (LDPE). Among the different composites, a decrease in oxygen permeability is observed as the CPG concentration increases. Regarding water vapor permeability, PBAT-based samples show a lower barrier effect than PE: in particular, permeability to water vapor assumes an increasing trend as the quantity of filler increases. The tuneable degradability of the final composite materials was defined by the disintegration degree (DD) determination under composting conditions in a laboratory-scale reactor. The developed materials prove to be valid biodegradable and eco-friendly alternatives to traditional thermoplastic polymers, such as LDPE, and can be applied in many fields, especially in package and mulch film applications

Preparation and characterization of innovative poly(butylene adipate terephthalate)‐based biocomposites for agri‐food packaging application

The present work reports on the preparation and subsequent mechanical, morphological and thermal characterization of composites based on poly(butylene adipate terephthalate) (PBAT), reinforced with micro-particles of inorganic bioabsorbable calcium-phosphate glass (CPG) at different contents up to 40 wt%. The PBAT-CPG composites were prepared by solvent casting. The resulting composite pellets were used for the injection molding of model 1BA specimens, according to standard UNI EN ISO 527. PBAT-CPG composites displayed an effective increase of the Young's modulus (E) up to 82% compared to the pristine polymer, while showing a reduction of the yield stress (σy) up to 20%, of the stress at break (σB) up to 46%, of the strain at break (εB) up to 57% and of the toughness (T) up to 72%. The values of E, σy and σB were also compared and validated with theoretical values calculated using Kerner's and Pukanszky's models. Scanning electron microscopy (SEM) images display homogeneous dispersion and distribution of the filler particles in the polymer matrix with no aggregates or phase separation that would cause a deterioration of the material properties. Infrared (IR) spectroscopy did not show structural variations of the polymer matrix due to the CPG presence. The oxygen permeability in PBAT-based samples assumes significantly lower values when benchmarked with the permeability of low-density polyethylene (LDPE). Among the different composites, a decrease in oxygen permeability is observed as the CPG concentration increases. Regarding water vapor permeability, PBAT-based samples show a lower barrier effect than polyethylene (PE): in particular, permeability to water vapor assumes an increasing trend as the quantity of filler increases. The tuneable degradation of the final composite materials was defined by the disintegration degree (DD) determination under composting conditions in a laboratory-scale reactor. The developed materials prove to be valid biodegradable and eco-friendly alternatives to traditional thermoplastic polymers, such as LDPE, and can be applied in many fields, especially in package and mulch film applications

Stradivari's Varnish Revisited: Feature Improvements Using Chemical Modification

The most widespread varnish formulations used by master violin-makers of the "Italian Golden Age", including Antonio Stradivari, were based on mixtures of siccative oils (e.g., linseed oil) and natural resins (e.g., colophony). Similar formulations are still used for the finish of contemporary instruments. Although most precious violins made by Stradivari and other Cremonese Masters are kept in museums, several instruments are still played and their finish may undergo deterioration due to contact with the players. Moreover, the decay of the traditional varnish may occur due to mechanical stress and natural aging caused by environmental agents (e.g., exposure to uncontrolled light, humidity, and temperature changes). The main aim of this research work is to investigate the possible improvement of varnish resistance to the decay induced by different aging processes. For this purpose, the traditional varnish (linseed oil/colophony 3:1 w/w) was recreated in the laboratory following an ancient recipe and then it was functionalized with a cross-linking agent (3-Glycidyloxypropyltrimethoxysilane, GLYMO). Plain and functionalized varnishes underwent artificial aging (UV light, temperature, and humidity variations), and their properties were comparatively studied using different techniques. All the results suggest that the functionalized varnish displays improved resistance to the aging process and particularly enhanced photostability and increased hardness (resistance to scratches)

Clinical Phenotypes of Atrial Fibrillation and Mortality Risk—A Cluster Analysis from the Nationwide Italian START Registry

: Patients with atrial fibrillation (AF) still experience a high mortality rate despite optimal antithrombotic treatment. We aimed to identify clinical phenotypes of patients to stratify mortality risk in AF. Cluster analysis was performed on 5171 AF patients from the nationwide START registry. The risk of all-cause mortality in each cluster was analyzed. We identified four clusters. Cluster 1 was composed of the youngest patients, with low comorbidities; Cluster 2 of patients with low cardiovascular risk factors and high prevalence of cancer; Cluster 3 of men with diabetes and coronary disease and peripheral artery disease; Cluster 4 included the oldest patients, mainly women, with previous cerebrovascular events. During 9857 person-years of observation, 386 deaths (3.92%/year) occurred. Mortality rates increased across clusters: 0.42%/year (cluster 1, reference group), 2.12%/year (cluster 2, adjusted hazard ratio (aHR) 3.306, 95% confidence interval (CI) 1.204-9.077, p = 0.020), 4.41%/year (cluster 3, aHR 6.702, 95%CI 2.433-18.461, p < 0.001), and 8.71%/year (cluster 4, aHR 8.927, 95%CI 3.238-24.605, p < 0.001). We identified four clusters of AF patients with progressive mortality risk. The use of clinical phenotypes may help identify patients at a higher risk of mortality

High concentration Er-doped phosphate glass optical fibers for single-frequency fiber amplifiers

The continuous improvement of interferometric gravitational-wave detectors (GWDs) and the preparations for next generation of GWDs set highly demanding requirements on their laser sources. A promising candidate to fulfill the challenging requirements of GWD laser sources is the hybrid master-oscillator power fiber amplifier (MOPFA) configuration. The implementation of a MOPFA relies principally on commercial silica glass-based optical fiber technology, which has been key in the successful development of high-power fiber amplifiers but that poses also a limitation to power scaling of these devices. It is well known that erbium (Er) ions tend to cluster in silica glass leading to ion-ion interactions and degradation of performance. The limited concentration of RE ions per unit length implies a limited optical gain per unit length and thus the requirement for long amplifying fiber lengths that enforce deleterious nonlinear effects, foremost stimulated Brillouin scattering (SBS). Numerous SBS suppression techniques have been proposed, alongside investigation of specialty optical fibers. One of the most promising solutions is the use of highly doped optical fibers based on multicomponent phosphate glass that allows the fabrication of ultra-compact active devices with minimized nonlinearities. To realize compact optical fiber amplifiers operating at 1.5 µm, a series of highly Er3+-doped custom phosphate glass compositions was designed and fabricated to be used as active materials for the core of the fiber amplifiers. Suitable cladding compositions were explored. Core and cladding glasses were synthesized by melt-quenching method. The core glass was cast into a cylindrical mold to form a rod, whereas the cladding tube was fabricated by extrusion technique. Phosphate fibers were then manufactured by drawing the preform assembled by rod-in-tube technique. Preliminary results of the application of the Er3+-doped phosphate fiber as laser active medium in a fully monolithic single-mode single-frequency core-pumped MOPFA setup resonantly pumped at around 1480 nm are presented

PREPARATION AND CHARACTERIZATION OF POLYMER-BASED BIOCOMPOSITES FOR AGRI-FOOD PACKAGING APPLICATIONS

The present work aims at the preparation and subsequent mechanical, morphological and thermal characterization of composites based on poly(butylene adipate terephthalate) (PBAT), loaded with micro-particles of inorganic biodegradable phosphate glass (PG)i at 2, 4, 10, 20 and 40 wt%. The reinforcement of PBAT has the purpose of modifying and modulating the mechanical and thermo-mechanical properties of the material to expand its application field especially in the food and agricultural packaging sectorii, thanks to the similarity of PBAT performance with polyethylene (PE)iii. The PBAT-PG specimens were subjected to uniaxial tensile stress and the collected data were analysed to obtain characteristic parameters such as Young's modulus (E), yield stress (σy), stress at break (σB), elongation at break (εB) and toughness (T) (Fig. 1). Scanning electron microscopy (SEM) images display homogeneous dispersion and distribution of the filler particles in the polymer matrix with no aggregates or phase separation (Fig. 2). PBAT is considered as one of the most promising biodegradable polyesters and this work demonstrates the successful realization of a PBAT-based composite material, as valid biodegradable and eco-friendly alternative to traditional thermoplastic polymers, such as PE

Lung Ultrasound in COVID-19 Pneumonia: Correlations with Chest CT on Hospital admission

Background: Lung ultrasound (LUS) is an accurate, safe, and cheap tool assisting in the diagnosis of several acute respiratory diseases. The diagnostic value of LUS in the workup of coronavirus disease-19 (COVID-19) in the hospital setting is still uncertain. Objectives: The aim of this observational study was to explore correlations of the LUS appearance of COVID-19-related pneumonia with CT findings. Methods: Twenty-six patients (14 males, age 64 ± 16 years) urgently hospitalized for COVID-19 pneumonia, who underwent chest CT and bedside LUS on the day of admission, were enrolled in this observational study. CT images were reviewed by expert chest radiologists, who calculated a visual CT score based on extension and distribution of ground-glass opacities and consolidations. LUS was performed by clinicians with certified competency in thoracic ultrasonography, blind to CT findings, following a systematic approach recommended by ultrasound guidelines. LUS score was calculated according to presence, distribution, and severity of abnormalities. Results: All participants had CT findings suggestive of bilateral COVID-19 pneumonia, with an average visual scoring of 43 ± 24%. LUS identified 4 different possible -abnormalities, with bilateral distribution (average LUS score 15 ± 5): focal areas of nonconfluent B lines, diffuse confluent B lines, small subpleural microconsolidations with pleural line irregularities, and large parenchymal consolidations with air bronchograms. LUS score was significantly correlated with CT visual scoring (r = 0.65, p < 0.001) and oxygen saturation in room air (r = -0.66, p < 0.001). Conclusion: When integrated with clinical data, LUS could represent a valid diagnostic aid in patients with suspect COVID-19 pneumonia, which reflects CT findings

Multi‑parametric MRI in the diagnosis and scoring of gastrointestinal acute graft‑versus‑host disease

Objectives Acute gastrointestinal graft-versus-host disease (GI-aGVHD) is a severe complication of allogeneic hematopoietic stem cell transplantation (HSCT). Diagnosis relies on clinical, endoscopic, and pathological investigations. Our purpose is to assess the value of magnetic resonance imaging (MRI) in the diagnosis, staging, and prediction of GI-aGVHD-related mortality. Methods Twenty-one hematological patients who underwent MRI for clinical suspicion of acute GI-GVHD were retrospectively selected. Three independent radiologists, blinded to the clinical findings, reanalyzed MRI images. The GI tract was evaluated from stomach to rectum by analyzing fifteen MRI signs suggestive of intestinal and peritoneal inflammation. All selected patients underwent colonoscopy with biopsies. Disease severity was determined on the basis of clinical criteria, identifying 4 stages of increasing severity. Disease-related mortality was also assessed. Results The diagnosis of GI-aGVHD was histologically confirmed with biopsy in 13 patients (61.9%). Using 6 major signs (diagnostic score), MRI showed 84.6% sensitivity and 100% specificity in identifying GI-aGVHD (AUC = 0.962; 95% confidence interval 0.891–1). The proximal, middle, and distal ileum were the segments most frequently affected by the disease (84.6%). Using all 15 signs of inflammation (severity score), MRI showed 100% sensitivity and 90% specificity for 1-month related mortality. No correlation with the clinical score was found. Conclusion MRI has proved to be an effective tool for diagnosing and scoring GI-aGVHD, with a high prognostic value. If larger studies will confirm these results, MRI could partly replace endoscopy, thus becoming the primary diagnostic tool for GI-aGVHD, being more complete, less invasive, and more easily repeatable. Key Points • We have developed a new promising MRI diagnostic score for GI-aGVHD with a sensitivity of 84.6% and specificity of 100%; results are to be confirmed by larger multicentric studies. • This MRI diagnostic score is based on the six MRI signs most frequently associated with GI-aGVHD: small-bowel inflammatory involvement, bowel wall stratification on T2-w images, wall stratification on post-contrast T1-w images, ascites, and edema of retroperitoneal fat and declivous soft tissues. • A broader MRI severity score based on 15 MRI signs showed no correlation with clinical staging but high prognostic value (100% sensitivity, 90% specificity for 1-month related mortality); these results also need to be confirmed by larger studies