411 research outputs found
Effects of processing on polyphenolic and volatile composition and fruit quality of clery strawberries
Strawberries belonging to cultivar Clery (Fragaria x ananassa (Duchesne ex Weston)), cultivated in central Italy were subjected to a multi‐methodological experimental study. Fresh and defrosted strawberries were exposed to different processing methods, such as homogenization, thermal and microwave treatments. The homogenate samples were submitted to CIEL*a*b* color analysis and Head‐Space GC/MS analysis to determine the impact of these procedures on phytochemical composition. Furthermore, the corresponding strawberry hydroalcoholic extracts were further analyzed by HPLC‐DAD for secondary metabolites quantification and by means of spectrophotometric in vitro assays to evaluate their total phenolic and total flavonoid contents and antioxidant activity. These chemical investigations confirmed the richness in bioactive metabolites supporting the extraordinary healthy potential of this fruit as a food ingredient, as well as functional food, highlighting the strong influence of the processing steps which could negatively impact on the polyphenol composition. Despite a more brilliant red color and aroma preservation, nonpasteurized samples were characterized by a lower content of polyphenols and antioxidant activity with respect to pasteurized samples, as also suggested by the PCA analysis of the collected data
Predictors of unemployment status in people with relapsing multiple sclerosis: a single center experience
Background: Multiple sclerosis (MS) is the most common cause of nontraumatic chronic neurological disability affecting young adults during their crucial employment years. Objectives: To evaluate patients and disease related factors associated to unemployment in a cohort of relapsing–remitting (RR) MS patients. Methods: We included RRMS patients with a follow-up of at least 1 year. We collected data about years of school education and employment status. Patients underwent a neuropsychological evaluation using the Brief International Cognitive Assessment for Multiple Sclerosis (BICAMS). Demographic and clinical predictors of unemployment were assessed through a multivariable stepwise logistic regression model. Results: We evaluated 260 consecutive RRMS patients. Employed patients were less frequently female (68.4% vs 83.3%, p = 0.006), less disabled (median Expanded Disability Status Scale (EDSS) score: 2.0 (0–7.0) vs 2.5 (0–7.5), p < 0.001), with more years of school education (mean ± standard deviation (SD), years: 13.74 ± 0.30 vs 10.86 ± 3.47, p < 0.001). Female sex and a higher EDSS score resulted associated with a greater risk of unemployment (OR 3.510, 95% CI 1.654–7.448, p = 0.001; OR 1.366, 95% CI 1.074–1.737, p = 0.011, respectively), whereas a greater number of years of schooling and current disease-modifying therapy exposure resulted protective factors (OR 0.788, 95% CI 0.723–0.858, p < 0,001; OR 0.414, 95% CI 0.217–0.790, p = 0.008, respectively). Conclusions: Understanding work is pervasively influenced by consequences of MS, we confirmed the impact of demographic, physical, and cognitive factors on employment status in RRMS patients
Electronic Structure of CeFeAsO1-xFx (x=0, 0.11/x=0.12) compounds
We report an extensive study on the intrinsic bulk electronic structure of
the high-temperature superconductor CeFeAsO0.89F0.11 and its parent compound
CeFeAsO by soft and hard x-ray photoemission, x-ray absorption and soft-x-ray
emission spectroscopies. The complementary surface/bulk probing depth, and the
elemental and chemical sensitivity of these techniques allows resolving the
intrinsic electronic structure of each element and correlating it with the
local structure, which has been probed by extended-x-ray absorption fine
structure spectroscopy. The measurements indicate a predominant 4f1 (i.e. Ce3+)
initial state configuration for Cerium and an effective valence-band-to-4f
charge-transfer screening of the core hole. The spectra also reveal the
presence of a small Ce f0 initial state configuration, which we assign to the
occurrence of an intermediate valence state. The data reveal a reasonably good
agreement with the partial density of states as obtained in standard density
functional calculations over a large energy range. Implications for the
electronic structure of these materials are discussed.Comment: Accepted for publication in Phys. Rev.
Ag/mgo nanoparticles via gas aggregation nanocluster source for perovskite solar cell engineering
Nanocluster aggregation sources based on magnetron-sputtering represent precise and versatile means to deposit a controlled quantity of metal nanoparticles at selected interfaces. In this work, we exploit this methodology to produce Ag/MgO nanoparticles (NPs) and deposit them on a glass/FTO/TiO2 substrate, which constitutes the mesoscopic front electrode of a monolithic perovskite-based solar cell (PSC). Herein, the Ag NP growth through magnetron sputtering and gas aggregation, subsequently covered with MgO ultrathin layers, is fully characterized in terms of structural and morphological properties while thermal stability and endurance against air-induced oxidation are demonstrated in accordance with PSC manufacturing processes. Finally, once the NP coverage is optimized, the Ag/MgO engineered PSCs demonstrate an overall increase of 5% in terms of device power conversion efficiencies (up to 17.8%)
Zno thin films growth optimization for piezoelectric application
The piezoelectric response of ZnO thin films in heterostructure-based devices is strictly related to their structure and morphology. We optimize the fabrication of piezoelectric ZnO to reduce its surface roughness, improving the crystalline quality, taking into consideration the role of the metal electrode underneath. The role of thermal treatments, as well as sputtering gas composition, is investigated by means of atomic force microscopy and x-ray diffraction. The results show an optimal reduction in surface roughness and at the same time a good crystalline quality when 75% O2 is introduced in the sputtering gas and deposition is performed between room temperature and 573 K. Subsequent annealing at 773 K further improves the film quality. The introduction of Ti or Pt as bottom electrode maintains a good surface and crystalline quality. By means of piezoelectric force microscope, we prove a piezoelectric response of the film in accordance with the literature, in spite of the low ZnO thickness and the reduced grain size, with a unipolar orientation and homogenous displacement when deposited on Ti electrode
The IL-17F/IL-17RC Axis Promotes Respiratory Allergy in the Proximal Airways
Summary The interleukin 17 (IL-17) cytokine and receptor family is central to antimicrobial resistance and inflammation in the lung. Mice lacking IL-17A, IL-17F, or the IL-17RA subunit were compared with wild-type mice for susceptibility to airway inflammation in models of infection and allergy. Signaling through IL-17RA was required for efficient microbial clearance and prevention of allergy; in the absence of IL-17RA, signaling through IL-17RC on epithelial cells, predominantly by IL-17F, significantly exacerbated lower airway Aspergillus or Pseudomonas infection and allergic airway inflammation. In contrast, following infection with the upper respiratory pathogen Staphylococcus aureus , the IL-17F/IL-17RC axis mediated protection. Thus, IL-17A and IL-17F exert distinct biological effects during pulmonary infection; the IL-17F/IL-17RC signaling axis has the potential to significantly worsen pathogen-associated inflammation of the lower respiratory tract in particular, and should be investigated further as a therapeutic target for treating pathological inflammation in the lung
Ballistic nanofriction
Sliding parts in nanosystems such as Nano ElectroMechanical Systems (NEMS)
and nanomotors, increasingly involve large speeds, and rotations as well as
translations of the moving surfaces; yet, the physics of high speed nanoscale
friction is so far unexplored. Here, by simulating the motion of drifting and
of kicked Au clusters on graphite - a workhorse system of experimental
relevance -- we demonstrate and characterize a novel "ballistic" friction
regime at high speed, separate from drift at low speed. The temperature
dependence of the cluster slip distance and time, measuring friction, is
opposite in these two regimes, consistent with theory. Crucial to both regimes
is the interplay of rotations and translations, shown to be correlated in slow
drift but anticorrelated in fast sliding. Despite these differences, we find
the velocity dependence of ballistic friction to be, like drift, viscous
Thermoelectric and Structural Properties of Sputtered AZO Thin Films with Varying Al Doping Ratios
Nanomaterials can be game-changers in the arena of sustainable energy production because they may enable highly efficient thermoelectric energy conversion and harvesting. For this purpose, doped thin film oxides have been proven to be promising systems for achieving high thermoelectric performances. In this work, the design, realization, and experimental investigation of the thermoelectric properties exhibited by a set of five Al:ZnO thin films with thicknesses of 300 nm and Al doping levels ranging from 2 to 8 at.% are described. Using a multi-technique approach, the main structural and morphological features of the grown thin films are addressed, as well as the electrical and thermoelectrical transport properties. The results show that the samples exhibited a Seebeck coefficient absolute value in the range of 22-33 mu V/K, assuming their maximum doping level was 8 at.%, while the samples' resistivity was decreased below 2 x 10(-3) Ohm center dot cm with a doping level of 3 at.%. The findings shine light on the perspectives of the applications of the metal ZnO thin film technology for thermoelectrics
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