Herein we investigate the effect of graphene decoration with metal nanoparticles, namely Ag and Pd, starting from pristine graphene (GR). Decoration is directly made on graphene obtained by Liquid ...Phase Exfoliation of natural graphite in eco-friendly solvents. The nanoparticles are synthesized in situ via chemical reduction from metal salts promoted by microwave treatment, resulting in metal nanoparticles directly stuck onto the pristine graphene surface. Sensing layers based on graphene and metal decorated graphenes were exposed to hydrogen, nitrogen dioxide and ammonia. Pristine graphene showed a marked specificity towards NO2 gas. Palladium nanoparticles enhanced graphene response towards hydrogen, while devices based on graphene/silver nanoparticles were highly specific towards ammonia detection. This eco-friendly and straightforward preparation method of graphene and graphene hybrids demonstrates an effective modulation of the sensing properties of graphene with respect to sensitivity and selectivity.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Melanoma is the most aggressive skin cancer; there is no cure in advanced stages. Identifying molecular participants in melanoma progression may provide useful diagnostic and therapeutic tools. FK506 ...binding protein 51 (FKBP51), an immunophilin with a relevant role in developmental stages, is highly expressed in melanoma and correlates with aggressiveness and therapy resistance. We hypothesized a role for FKBP51 in melanoma invasive behaviour. FKBP51 promoted activation of epithelial-to-mesenchymal transition (EMT) genes and improved melanoma cell migration and invasion. In addition, FKBP51 induced some melanoma stem cell (MCSC) genes. Purified MCSCs expressed high EMT genes levels, suggesting that genetic programs of EMT and MCSCs overlap. Immunohistochemistry of samples from patients showed intense FKBP51 nuclear signal and cytoplasmic positivity for the stem cell marker nestin in extravasating melanoma cells and metastatic brains. In addition, FKBP51 targeting by small interfering RNA (siRNA) prevented the massive metastatic substitution of liver and lung in a mouse model of experimental metastasis. The present study provides evidence that the genetic programs of cancer stemness and invasiveness overlap in melanoma, and that FKBP51 plays a pivotal role in sustaining such a program.
Global grey matter (GM) loss has been reported in multiple sclerosis (MS). We addressed the question of if and where GM loss is localized by means of optimized voxel-based morphometry, applied to MRI ...studies of 51 patients with clinically defined relapsing–remitting MS and 34 age-matched normal subjects, segmented into normal and abnormal brain tissues using a multiparametric approach. Segmented GM volumes were subsequently compared on a voxel-by-voxel basis to highlight regions of relative GM loss (
P < 0.05, corrected for multiple comparisons at AnCova).
Additionally, localized differences in brain asymmetry between the MS and the control groups were assessed by comparing on a voxel-by-voxel basis maps of GM differences between the two hemispheres (
P < 0.05 corrected for multiple comparisons).
In MS patients, GM volume was significantly decreased at the level of the left fronto-temporal cortex and precuneus, as well as of anterior cingulate gyrus and of caudate nuclei bilaterally. The only cortical region of significant GM loss in the right hemisphere was located in the postcentral area.
Furthermore, GM loss regions were colocalized with increased GM asymmetries (Left < Right) in MS, confirming a preferential left-sided GM loss.
Caudate atrophy correlated with lesion load, while no correlation between cortical regional GM loss and disease duration, clinical status or lesion load emerged.
Our findings suggest that in RR-MS cortical GM reduction preferentially involves left fronto-temporal structures and deep GM, the latter correlating preferentially to global lesion load.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
The extremely high sensitivity to the external environment and the high specific surface area, as well as the absence of bulk phenomena that could interfere with the response signal, make graphene ...highly attractive for the applications in the field of sensing. Among the various methods for producing graphene over large areas, liquid phase exfoliation (LPE) appears to be very promising, especially if combined with inkjet printing (IJP), which offers several advantages, including the selective and controlled deposition of small ink volumes and the versatility of the exploitable inks and substrates. Herein we present a feasibility study of chemiresistive gas sensors inkjet-printed onto paper substrates, in which a LPE graphene suspension dispersed in a water/isopropanol (H2O/IPA) mixture is used as sensing ink. The device performances, in terms of relative conductance variations, upon exposure to NO2 at standard ambient temperature and pressure, are analysed. In addition, we examine the effect of the substrate morphology and, more specifically, of the ink/substrate interaction on the device performances, by comparing the response of different chemiresistors fabricated by dispensing the same suspension also onto Al2O3 and Si/SiO2 substrates and carrying out a supportive atomic force microscopy analysis. The results prove the possibility to produce sensor devices by means of a wholly environmentally friendly, low-cost process that meets the requests coming from the increasing field of paper-based electronics and paving the way towards a flexible, green-by-design mass production.
Background and purpose
Grey matter (GM) and white matter (WM) are both affected in multiple sclerosis (MS). WM is predominantly involved in inflammatory demyelination of relapsing–remitting MS ...(RRMS), whereas GM is predominantly involved in neurodegenerative processes of secondary progressive MS. Thus, we investigated the ratio between GM and WM volumes in predicting MS evolution.
Methods
The present 10‐year retrospective cohort study included 149 patients with newly‐diagnosed RRMS, undergoing magnetic resonance imaging for segmentation and brain volumetry. The ratio between GM and normal‐appearing WM (NAWM) volumes was calculated for each subject. Outcome measures of interest were Expanded Disability Status Scale (EDSS) progression, reaching EDSS 4.0 and conversion to secondary progressive (SP) MS.
Results
During a period of 10.6 ± 2.4 years, a median 1.5 EDSS progression was observed (range 0–5.5), 54 subjects (36.2%) reached EDSS 4.0 and 30 subjects (20.1%) converted to SP. With ordinal logistic regression models, EDSS progression was associated with GM:NAWM ratio (coefficient, −2.918; 95% CI, −4.739–1.097). With Cox regression models, subjects with higher GM:NAWM ratio at diagnosis had a 90% lower rate of reaching EDSS 4.0 (hazard ratio, 0.111; 95% CI, 0.020–0.609) and of converting to secondary progressive MS (hazard ratio, 0.017; 95% CI, 0.001–0.203) compared with subjects with lower GM:NAWM ratio.
Conclusions
The GM:NAWM ratio is a predictor of disability progression and of SP conversion in subjects with newly diagnosed RRMS, suggesting that GM and NAWM are variably affected in relation to disease evolution from the early phases of MS.
Full text
Available for:
BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Objective:
The objective of this paper is to identify clinical or magnetic resonance imaging (MRI) predictors of long-term clinical progression in a large cohort of multiple sclerosis (MS) patients.
...Methods:
A total of 241 relapsing–remitting (RR) MS patients were included in a nine-year follow-up (FU) study. The reference MRIs were acquired at baseline (BL) as part of a multicenter, cross-sectional, clinical-MRI study. Volumetric MRI metrics were measured by a fully automated, operator-independent, multi-parametric segmentation method. Clinical progression was evaluated as defined by: conversion from RR to secondary progressive (SP) disease course; progression of Expanded Disability Status Scale (EDSS); achievement and time to reach EDSS 4.
Results:
We concluded that conversion from RR to SP (OR 0.79; CI 0.7–0.9), progression of EDSS (OR 0.85; CI 0.77–0.93), achievement of EDSS 4 (OR 0.8; CI 0.7–0.9), and time to reach EDSS 4 (HR 0.88; CI 0.82–0.94) were all predicted by BL gray matter (GM) volume and, except for progression of EDSS, by BL EDSS (respectively: (OR 2.88; CI 1.9–4.36), (OR 2.7; CI 1.7–4.2), (HR 3.86; CI 1.94–7.70)).
Conclusions:
BL GM volume and EDSS are the best long-term predictors of disease progression in RRMS patients with a relatively long and mild disease.
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
To measure white matter (WM) and gray matter (GM) atrophy and lesion load in a large population of patients with multiple sclerosis (MS) using a fully automated, operator-independent, multiparametric ...segmentation method.
The study population consisted of 597 patients with MS and 104 control subjects. The MRI parameters were abnormal WM fraction (AWM-f), global WM-f (gWM-f), and GM fraction (GM-f).
Significant differences between patients with MS and control subjects included higher AWM-f and reduced gWM-f and GM-f. MRI data showed significant differences between patients with relapsing-remitting and secondary progressive forms of MS. Significant correlations between MRI parameters and between MRI and clinical data were found.
Patients with multiple sclerosis have significant atrophy of both white matter (WM) and gray matter (GM); secondary progressive patients have significantly more atrophy of both WM and GM than do relapsing-remitting patients and a significantly higher lesion load (abnormal WM fraction); lesion load is related to both WM and even more to GM atrophy; lesion load and WM and GM atrophy are significantly related to Expanded Disability Status Scale score and age at onset (suggesting that the younger the age at disease onset, the worse the lesion load and brain atrophy); and GM atrophy is the most significant MRI variable in determining the final disability.
Previous studies have shown a preferential loss of grey matter in fronto-temporal regions in patients with multiple sclerosis. Studies of correlates of disease severity are more controversial, ...because some studies have suggested an association between sensorimotor cortex atrophy and Expanded Disability Status Scale score, while others did not find such a correlation. The objective of this study was to assess the correlation of regional loss of grey matter and white matter with indexes of clinical and radiological severity in relapsing—remitting multiple sclerosis, including the Expanded Disability Status Scale and lesion load. Correlations between Expanded Disability Status Scale, lesion load and disease duration were assessed in 128 patients with relapsing—remitting multiple sclerosis (Expanded Disability Status Scale range 1.0—6.0) using optimized voxel-based morphometry. Bilateral loss of grey matter in sensorimotor cortices was correlated with Expanded Disability Status Scale, and tissue loss also involved adjacent white matter, extending along pyramidal tracts to the brainstem. Increasing lesion load was correlated with loss of deep grey matter and white matter. No specific region of grey matter or white matter showed a significant correlation with disease duration. These findings support the hypothesis that motor neuron involvement plays a major role in the progression of physical disability. Lesion load accrual affects mainly highly interconnected subcortical structures, while disease duration has a less significant impact on brain atrophy, probably owing to the inter-subject heterogeneity of the clinical course of the disease.
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK
This study was designed to validate a novel semi-automated segmentation method to measure regional intra-orbital fat tissue volume in Graves' ophthalmopathy. Twenty-four orbits from 12 patients with ...Graves' ophthalmopathy, 24 orbits from 12 controls, ten orbits from five MRI study simulations and two orbits from a digital model were used. Following manual region of interest definition of the orbital volumes performed by two operators with different levels of expertise, an automated procedure calculated intra-orbital fat tissue volumes (global and regional, with automated definition of four quadrants). In patients with Graves' disease, clinical activity score and degree of exophthalmos were measured and correlated with intra-orbital fat volumes. Operator performance was evaluated and statistical analysis of the measurements was performed. Accurate intra-orbital fat volume measurements were obtained with coefficients of variation below 5%. The mean operator difference in total fat volume measurements was 0.56%. Patients had significantly higher intra-orbital fat volumes than controls (p<0.001 using Student's t test). Fat volumes and clinical score were significantly correlated (p<0.001). The semi-automated method described here can provide accurate, reproducible intra-orbital fat measurements with low inter-operator variation and good correlation with clinical data.
Full text
Available for:
NUK, OILJ, SAZU, UKNU, UL, UM, UPUK, VSZLJ
The working principle of composite polymer vapor sensors is basically to exploit the vapor absorption properties of an insulating polymer whose electrical properties are modulated by a conductive ...“filler”. Carbon black and graphite powder have already been used as “filler” materials Sens. Actuators B87 (2002) 130, Anal. Chem. 74 (2002) 1307, Sens. Actuators B66 (2000) 37, Anal. Chem. 70 (1998) 2560. In this work we fabricate and characterize vapor sensors with a new type of “filler”: carbon nanoparticles obtained by flame synthesis. Electrochemically prepared porous silicon with a 40% porosity has been used as the substrate for the carbon growth. Carbon nanoparticles have been characterized by AFM, SEM, FTIR; XRD, diffraction laser spectroscopy, nitrogen isothermal adsorption and visible optical micrography. The carbon structures seem composed of “units” whose size is in the range 5–20
nm. Composite thin films have been realized using mainly poly(methyl-methacrylate) (PMMA) as polymeric insulating matrix. Thin films of the composite are used to realize chemiresistor sensing devices. The characteristics of the sensors responses to volatile organic compounds (VOCs) are related to filler types in order to optimize the sensing device and show the importance of the filler characteristics.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
PDF
