99 research outputs found
A selective ratiometric fluorescent probe for noâwash detection of PVC microplastic
Microplastics (MP) are micrometric plastic particles present in drinking water, food and the environment that constitute an emerging pollutant and pose a menace to human health. Novel methods for the fast detection of these new contaminants are needed. Fluorescenceâbased detection exploits the use of specific probes to label the MP particles. This method can be environmentally friendly, lowâcost, easily scalable but also very sensitive and specific. Here, we present the synthesis and application of a new probe based on peryleneâdiimide (PDI), which can be prepared in a few minutes by a oneâpot reaction using a conventional microwave oven and can be used for the direct detection of MP in water without any further treatment of the sample. The green fluorescence is strongly quenched in water at neutral pH because of the formation dimers. The ability of the probe to label MP was tested for polyvinyl chloride (PVC), polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polystyrene (PS), poly methyl methacrylate (PMMA) and polytetrafluoroethylene (PTFE). The probe showed considerable selectivity to PVC MP, which presented an intense red emission after staining. Interestingly, the fluorescence of the MP after labeling could be detected, under excitation with a blue diode, with a conventional CMOS color camera. Good selectivity was achieved analyzing the red to green fluorescence intensity ratio. UVâ Vis absorption, steadyâstate and timeâresolved fluorescence spectroscopy, fluorescence anisotropy, fluorescence wideâfield and confocal laser scanning microscopy allowed elucidating the mechanism of the staining in detail
A new methodological approach to correlate protective and microscopic properties by soft x-ray microscopy and solid state nmr spectroscopy: The case of cusaâs stone
Hydrophobic treatment is one of the most important interventions usually carried out for the conservation of stone artefacts and monuments. The study here reported aims to answer a general question about how two polymers confer different protective performance. Two fluorinated-based polymer formulates applied on samples of Cusaâs stone confer a different level of water repellence and water vapour permeability. The observed protection action is here explained on the basis of chemico-physical interactions. The distribution of the polymer in the pore network was investigated using scanning electron microscopy and X-ray microscopy. The interactions between the stone substrate and the protective agents were investigated by means of solid state NMR spectroscopy. The ss-NMR findings reveal no significant changes in the chemical neighbourhood of the observed nuclei of each protective agent when applied onto the stone surface and provide information on the changes in the organization and dynamics of the studied systems, as well as on the mobility of polymer chains. This allowed us to explain the different macroscopic behaviours provided by each protective agent to the stone substrate
Sicilian byzantine icons through the use of non-invasive imaging techniques and optical spectroscopy: The case of the madonna dellâelemosina
The iconographic heritage is one of the treasures of Byzantine art that have enriched the south of Italy, and Sicily in particular, since the early 16th century. In this work, the investigations of a Sicilian Icon of Greek-Byzantine origin, the Madonna dellâElemosina, is reported for the first time. The study was carried out using mainly non-invasive imaging techniques (photography in reflectance and grazing visible light, UV fluorescence, infrared reflectography, radiography, and computed tomography) and spectroscopic techniques (X-ray fluorescence and infrared spectroscopy). The identification of the constituent materials provides a decisive contribution to the correct historical and artistic placement of the Icon, a treasure of the Eastern European historical community in Sicily. Some hidden details have also been highlighted. Most importantly, the information obtained enables us to define its conservation state, the presence of foreign materials, and to direct its protection and restoration
Clinical presentations leading to arrhythmogenic left ventricular cardiomyopathy
Objectives To describe a cohort of patients with arrhythmogenic left ventricular cardiomyopathy (ALVC), focusing on the spectrum of the clinical presentations. Methods Patients were retrospectively evaluated between January 2012 and June 2020. Diagnosis was based on (1) â„3 contiguous segments with subepicardial/midwall late gadolinium enhancement in the left ventricle (LV) at cardiac magnetic resonance plus a likely pathogenic/pathogenic arrhythmogenic cardiomyopathy (AC) associated genetic mutation and/or familial history of AC and/or red flags for ALVC (ie, negative T waves in V4-6/aVL, low voltages in limb leads, right bundle branch block like ventricular tachycardia) or (2) pathology examination of explanted hearts or autoptic cases suffering sudden cardiac death (SCD). Significant right ventricular involvement was an exclusion criterion. Results Fifty-two patients (63% males, age 45 years (31-53)) composed the study cohort. Twenty-one (41%) had normal echocardiogram, 13 (25%) a hypokinetic non-dilated cardiomyopathy (HNDC) and 17 (33%) a dilated cardiomyopathy (DCM). Of 47 tested patients, 29 (62%) were carriers of a pathogenic/likely pathogenic DNA variant. Clinical contexts leading to diagnosis were SCD in 3 (6%), ventricular arrhythmias in 15 (29%), chest pain in 8 (15%), heart failure in 6 (12%) and familial screening in 20 (38%). Thirty patients (57%) had previously received a diagnosis other than ALVC with a diagnostic delay of 6 years (IQR 1-7). Conclusions ALVC is hidden in different clinical scenarios with a phenotypic spectrum ranging from normal LV to HNDC and DCM. Ventricular arrhythmias, chest pain, heart failure and SCD are the main clinical presentations, being familial screening essential for the affected relatives' identification
On the integration of Riemann-measurable vector-valued functions
We confine our attention to convergence theorems and descriptive relationships within some subclasses of Riemann-measurable vector-valued functions that are based on the various generalizations of the Riemann definition of an integral
Description of the limit set of Henstock-Kurzweil integral sums of vector-valued functions
Let f be a function defined on [0, 1] and taking values in a Banach space
X. We show that the limit set IHK(f) of Henstock-Kurzweil integral sums is
non-empty and convex when the function f has an integrable majorant and
X is separable. In the same setting we give a complete description of the
limit set
How Many Secret Details Could a Systematic Multi-Analytical Study Reveal About the Mysterious Fresco Trionfo della Morte?
The âTrionfo della morteâ is a detached fresco painting dated at the half of the XV century. Its history is strictly connected with the history of Palermo and it is considered a symbol of the late Gothic period. Some small areas of the fresco were analyzed using a combination of non-invasive techniques and hand-held instrumentations (multispectral imaging analysis, X-ray fluorescence (XRF), and IR spectroscopy). The characterization of the nature of pigments used in its realization and restoration works was performed and some indications about its conservation state were obtained. More interestingly, some hidden details were revealed on the mysterious painting. They constitute additional evidence of the preciousness of the fresco
Multiresolution Texture Analysis for Human Oocyte Cytoplasm Description
In this work we present an approach based on image texture analysis to obtain a description of oocyte cytoplasm which could aid the medical expert in the selection of oocytes to be used for assisted insemination. More specifically, we describe some characteristics such as different levels of uniformity and/or granularity in the oocyte cytoplasm, using multiresolution texture analysis applied to light microscope images. To this aim, we evaluate some statistical measures in the wavelet transform domain of image regions and classify them according to different levels of granularity. Preliminary experimental results on a collection of light microscope images of oocytes are reported to show the effectiveness of the proposed approach
- âŠ