356 research outputs found
Forcing scale invariance in multipolarization SAR change detection
This paper considers the problem of coherent (in the sense that both amplitudes and relative phases of the polarimetric returns are used to construct the decision statistic) multi-polarization SAR change detec- tion starting from the availability of image pairs exhibiting possible power mismatches/miscalibrations. The principle of invariance is used to characterize the class of scale-invariant decision rules which are insensitive to power mismatches and ensure the Constant False Alarm Rate (CFAR) property. A maximal invariant statistic is derived together with the induced maximal invariant in the parameter space which significantly compress the data/parameters domain. A Generalized Likelihood Ratio Test (GLRT) is synthesized both for the cases of two- and three-polarimetric channels. Interestingly, for the two-channel case, it is based on the comparison of the condition number of a data-dependent matrix with a suitable threshold. Some additional invariant decision rules are also proposed. The performance of the considered scale-invariant structures is compared to those from two non- invariant counterparts using both simulated and real radar data. The results highlight the robustness of the proposed method and the performance tradeoff involve
Correlation analysis between foveal avascular zone and near peripheral retinal hypoperfusion in multiple sclerosis: a wide field optical coherence tomography angiography study
The identification of non-invasive biomarkers to investigate and monitor retinal structural and vascular changes in multiple sclerosis (MS) represents an interesting source of debate. Until now optical coherence tomography angiography (OCTA) evaluated the foveal avascular zone (FAZ) and areas of retinal non-perfusion only in the macular region in MS patients. It could be interesting to identify possible biomarkers, useful in assessing the ischemic areas also in the near peripheral retina, since FAZ enlargement and the areas of peripheral retinal non-perfusions share common pathogenic processes. In this cross-sectional study, we investigated the correlation between the FAZ area and retinal vessel density (VD) in the near peripheral retina by new wide-field optical coherence tomography angiography (OCTA) in patients affected by relapsing-remitting multiple sclerosis (RR-MS). Moreover, we compared the FAZ area and the VD of superficial and deep capillary plexuses in the fovea region and in the near peripheral retina (6.4 x 6.4 mm) between RR-MS patients and healthy controls by means of a Solix full-range OCTA. Last, we also detected the changes in structural OCT parameters (ganglion cell complex and retinal nerve fiber layer). Thirty-three eyes of 33 RR-MS patients and 35 eyes of 35 healthy controls were enrolled. RR-MS patients showed a lower VD in the superficial capillary plexus and a significant increase in the FAZ area compared with controls. The deep capillary plexus revealed a reduced VD although not statistically significant in patients with respect to controls. In the patients' group, the FAZ area showed significantly negative correlations with VD of superficial capillary plexuses in the foveal and whole region, while the FAZ area did not negatively correlate with the VD of the deep capillary plexus. The significant correlations among OCTA parameters could demonstrate the FAZ area as a possible biomarker for assessing the perfusion status in the near peripheral retina, useful in RR-MS management. These findings could confirm the role of vascular dysfunction in the pathogenetic mechanisms of MS
Urantide Conformation and Interaction with the Urotensin-II Receptor
Urotensin II (U-II) is a disulfide bridged peptide hormone identified as the ligand of a G protein-coupled receptor. Human U-II (H-Glu-Thr-Pro-Asp-c[Cys-Phe-Trp-Lys-Tyr-Cys]-Val-OH) has been described as the most potent vasoconstrictor compound identified to date. We have previously identified the compound termed urantide (H-Asp-c[Pen-Phe-DTrp-Orn-Tyr-Cys]-Val-OH), which is the most potent UT receptor (UTR) antagonist described to date. Urantide may have potential clinical value in the treatment of atherosclerosis. In the present study, we studied the conformational preferences of urantide in DPC micelles and developed a urantide/UTR interaction model. This model can help the design of novel peptides and small molecules as UTR antagonists
Google Maps Timeline: An open-access digital tool to monitor walking abilities in people with multiple sclerosis
Introduction: Gait impairment is common in multiple sclerosis (MS), but difficult to evaluate in clinical practice. In this proof-of-concept observational study, we compared walking ability recorded by Google Maps Timeline to conventional clinical measures in people with MS. Methods: We used open-access Google Maps Timeline to record the total number of days with walking activity, walking distance, walking time, and walking speed. Each Google Maps Timeline variable was included in a different stepwise linear regression model including all conventional clinical variables. Results: We included nine people with MS (age 43.1 ± 6.6 years; females 55.6%; disease duration 12.7 ± 3.1 years; median Expanded Disability Status Scale 3.0 (range 1.0-5.5)). Higher percentage of days with recorded walking was associated with lower Fatigue Severity Scale (p = 0.01), and higher MS Walking Scale (p = 0.04). Longer average daily walking distance was associated with shorter Timed-25 Foot Walking Test (p = 0.02), lower Expanded Disability Status Scale (p = 0.01), and higher Euro-Quality of Life (p = 0.04). Longer average daily walking time was associated with shorter Timed-25 Foot Walking Test (p = 0.03). Higher walking speed was associated with lower Fatigue Severity Scale (p = 0.04). Conclusion: Google Maps Timeline parameters provide actual estimates of daily walking activities in MS
âA warning from Marsâ: effect of microclimate changes at the Specola Museum of Palermo
The Specola Museum is located at the Palermo Astronomical Observatory and preserves most of its material heritage. It is part of the Museum System of the University of Palermo (SiMuA) and its management and conservation are entrusted to the INAF - Astronomical Observatory of Palermo. Among the historical instruments on display, there is a 19th-century painted wooden globe reproducing the surface of Mars. It has been on display in a showcase, inside the Merz Telescope Hall, for about 20 years without undergoing any type of intervention or evident deterioration sign. From 2021, in less than two years, damages of its pictorial layers occurred at a progressive rate. The European Standard EN 15757 explains that hygroscopic materials are highly vulnerable to microclimate changes. The wooden globe was in good conditions after two decades of permanence at the museum, but the recent control and management of the indoor climate was not compatible with the past climate history of the globe to which it has adapted.
The speed of the degradation made it evident that the microclimatic conditions of the room changed abruptly. The warning deduced from the Mars globe deterioration was hence easy to decode: there is something wrong with this climate!
It is well known that museum microclimate plays a key role in the conservation of the objects on display. It may trigger or aggravate degradation processes of the materials constituting the object exhibited and affect their âlife expectancyâ. Moreover, each object responses peculiarly to environment variability, depending on its composition and conservation history. When an artifact is composed of different materials, unexpected synergistic effects may develop. Finding appropriate values range of temperature, relative humidity and illuminance and managing them to guarantee the conservation of the entire collection, and at the same time improving the thermal comfort for people working there, is a difficult task. The issue becomes even more challenging in buildings not originally designed for conservation purposes, as the Specola Museum, located in the ancient observatory rooms, built in 1790 on the top of the 12nd-century Royal Palace.
An accurate restoration has been made, and conservation measures have been adopted, to stop the serious deteriorating processes affecting the model of Mars but the risk of further deterioration phenomena involving other objects is expected to increase substantially if no actions are taken.
This contribution intends to present the results of the preliminary study concerning the thermo-hygrometric records taken in the Merz Telescope Hall over the last two years and propose specific actions to improve its microclimate conditions.
References
Carotenuto M. R., Randazzo D., Chinnici I., Genua G., Preventive Conservation Projects on LAM Materials at the INAF-Astronomical Observatory of Palermo âG.S. Vaianaâ, Bulletin of the AAS, 54(2) (2022)
Carotenuto M. R., Chinnici I. et al., Rapporto tecnico INAF 2022 - Il Museo della Specola: progetti per la conservazione, la fruizione, la comunicazione (2018-2020)
Camuffo D., Microclimate for cultural heritage. Measurement, Risk Assessment, Conservation, Restoration, and Maintenance of Indoor and Outdoor Monuments, Elsevier, third Edition (2019)
Antomarchi C., Pedersoli Jr., Michalski S., Guide to Risk Management, ICCROM (2016)
FoderaÌ Serio G., Chinnici I., L'Osservatorio Astronomico di Palermo, Palermo (1997
Low serum 25âhydroxy-vitamin D levels are associated with cognitive impairment in multiple sclerosis
Background: Cognitive impairment frequently affects people with multiple sclerosis (MS). Low vitamin D has been associated with cognitive dysfunction in different neurodegenerative diseases, and, in MS, with motor disability and disease activity. We aim to investigate associations between vitamin D and cognitive status in MS. Methods: In this cross-sectional study, we included 181 MS patients, recruited consecutively at the MS Unit of the Policlinico Federico II University Hospital of Naples, Italy, between January and April 2022, with serum 25âhydroxy (25-OH) vitamin D measurements using Chemiluminescence-ImmunoAssay, and cognitive assessment using the Brief International Cognitive Assessment for MS (BICAMS), which includes Symbol Digit Modalities Test (SDMT), California Verbal Learning Test-II (CVLT-II) and Brief Visuospatial Memory Test-Revised (BVMT-R). We collected demographics (age, sex, education), and clinical variables (disease duration, disease subtype, expanded disability status scale (EDSS), disease modifying treatment, relapses in previous 12 months, vitamin D supplementation, comorbidities). For a subset of patients (n = 41, 23.2% of the total sample), we collected Beck Depression Inventory-II, Beck Anxiety Inventory, and Modified Fatigue Impact Scale. Results: At univariable linear regression models, serum 25-OH-vitamin D levels were 0.9 ng/mL higher for each unit increase of SDMT adjusted scores (Coeff=0.93; 95%CI=0.81, 1.04; p<0.01), 0.7 ng/mL higher for each unit increase of CVLT-II adjusted scores (Coeff=0.68; 95%CI=0.53, 0.83; p<0. 01), 0.6 ng/mL higher for each unit increase of BVMT-R adjusted scores (Coeff=0.58; 95%CI=0.43, 0.73; p<0.01), -9.63 ng/mL lower for each impaired BICAMS test (Coeff=-9.63; 95%CI=-11.48, -7.79; p<0.01), and -2.2 ng/mL lower for each unit increase of EDSS (Coeff=-2.16; 95%CI=-3.57, -0.75; p<0.01). At multivariable linear regression models, we confirmed associations between 25-OH-vitamin D and EDSS (Coeff=-2.09; 95%CI=-4.45, -0.43; p<0.01), SDMT (Coeff=0.75; 95%CI=0.60, 0.90; p<0.01), and CVLT-II (Coeff=0.14; 95%CI=0.01, 0.28; p = 0. 04). Results remained unchanged when including depression, anxiety and fatigue scores. Conclusions: Lower serum 25-OH-vitamin D was associated with worse cognitive function in MS. Future studies should consider longitudinal variations in cognitive function in relation to vitamin D supplementation
Assessment of neuroactive steroids in cerebrospinal fluid comparing acute relapse and stable disease in relapsing-remitting multiple sclerosis
Previous studies have reported an involvement of neuroactive steroids as neuroprotective and anti-inflammatory agents in neurological disorders such as multiple sclerosis (MS); an analysis of their profile during a specific clinical phase of MS is largely unknown. The pregnenolone (PREG), dehydroepiandrosterone (DHEA), and allopregnanolone (ALLO) profile was evaluated in cerebrospinal fluid (CSF) in relapsing-remitting multiple sclerosis (RR-MS) patients as well as those in patients affected by non-inflammatory neurological (control group I) and without neurological disorders (control group II). An increase of PREG and DHEA values was shown in CSF of male and female RR-MS patients compared to those observed in both control groups. The ALLO values were significantly lower in female RR-MS patients than those found in male RR-MS patients and in female without neurological disorder. During the clinical relapse, we observed female RR-MS patients showing significantly increased PREG values compared to female RR-MS patients in stable phase, while their ALLO values showed a significant decrease compared to male RR-MS patients of the same group. Male RR-MS patients with gadolinium-enhanced lesions showed PREG and DHEA values higher than those found in female RR-MS patients with gadolinium-enhanced lesions. Similary, male RR-MS patients with gadolinium-enhanced lesions showed PREG and DHEA values higher than male without gadolinium-enhanced lesions. Female RR-MS patients with gadolinium-enhanced lesions showed DHEA values higher than those found in female RR-MS patients with gadolinium-enhanced lesions. Male and female RR-MS patients with gadolinium-enhanced lesions showed ALLO values higher than those found in respective gender groups without gadolinium-enhanced lesions. ALLO values were lower in male than in female RR-MS patients without gadolinium-enhanced lesions. Considering the pharmacological properties of neuroactive steroids and the observation that neurological disorders influence their concentrations, these endogenous compounds may have an important role as prognostic factors of the disease and used as markers of MS activity such as relapses
Late and early onset dementia: what is the role of vascular factors? A retrospective study.
Neuropathology of Alzheimer's disease (AD) demonstrates that the common occurrence of vascular lesions and vascular factors is suggested to contribute significantly to the clinical progression of the disease. This study has assessed the presence of vascular brain lesions and risk factors in subjects with diagnosis of AD and their influence on the disease course both in Late Onset Dementia (LOD) and in Early Onset Dementia (EOD).
METHODS:
MRI scans of 374 LOD and of 67 EOD patients were evaluated for the presence of vascular associated lesions and rated according to the age-related white matter changes (ARWMC) scale as "pure degenerative", "mixed" and "vascular" cases of dementia. Vascular risk factors burden (hypertension, diabetes, dyslipidemia, myocardial infarction) and disease progression were also assessed.
RESULTS:
44% of LOD cases and 46% of EOD were classified as "mixed dementia cases". The vascular risk factors burden showed an increase from the pure degenerative to the pure vascular forms. Disease progression, calculated in two years using the Mini Mental State Evaluation (MMSE), Activities of Daily Living (ADL) and Instrumental Activities of Daily Living (IADL) scores, did not reveal differences among the three different classes of dementias.
CONCLUSIONS:
Vascular lesions are found in the majority of LOD cases and in about one half of EOD. This observation is consistent with the hypothesis of a synergistic effect of the degenerative and vascular factors on the development of cognitive dysfunction. The linear increase of the vascular burden supports the idea of a continuum spectrum between the pure degenerative and the pure vascular forms of adult-onset dementia disorder
Performance prediction of the coherent radar detector on measured UAVs data
This paper presents measurements of Radar Cross Section (RCS) of five Unmanned Aerial Vehicles (UAVs), comprising both consumer grade and professional small drones, collected in a semi-controlled environment as a function of azimuth aspect angle, polarization and frequency in the range 8.2-18 GHz. A first-order statistical analysis of the measured RCSs is firstly reported prior to assessing the radar detection performance on both measured and bespoke simulated data (leveraging the results of the developed statistical analysis), including, as benchmark terms, the curves for non-fluctuating and Rayleigh fluctuating targets
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