489 research outputs found

    Identifying the lights position in photometric stereo under unknown lighting

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    Reconstructing the 3D shape of an object from a set of images is a classical problem in Computer Vision. Photometric stereo is one of the possible approaches. It stands on the assumption that the object is observed from a fixed point of view under different lighting conditions. The traditional approach requires that the position of the light sources is accurately known. It has been proved that the lights position can be estimated directly from the data, when at least 6 images of the observed object are available. In this paper, we give a Matlab implementation of the algorithm for solving the photometric stereo problem under unknown lighting, and propose a simple shooting technique to solve the bas-relief ambiguity.Comment: new versio

    Metal-Free Modified Boron Nitride for Enhanced CO2 Capture

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    Porous boron nitride is a new class of solid adsorbent with applications in CO2 capture. In order to further enhance the adsorption capacities of materials, new strategies such as porosity tuning, element doping and surface modification have been taken into account. In this work, metal-free modification of porous boron nitride (BN) has been prepared by a structure directing agent via simple heat treatment under N2 flow. We have demonstrated that textural properties of BN play a pivotal role in CO2 adsorption behavior. Therefore, addition of a triblock copolymer surfactant (P123) has been adopted to improve the pore ordering and textural properties of porous BN and its influence on the morphological and structural properties of pristine BN has been characterized. The obtained BN-P123 exhibits a high surface area of 476 m2/g, a large pore volume of 0.83 cm3/g with an abundance of micropores. More importantly, after modification with P123 copolymer, the capacity of pure CO2 on porous BN has improved by about 34.5% compared to pristine BN (2.69 mmol/g for BN-P123 vs. 2.00 mmol/g for pristine BN under ambient condition). The unique characteristics of boron nitride opens up new routes for designing porous BN, which could be employed for optimizing CO2 adsorption

    K Index in cerebrospinal fluid: a valid tool in multiple sclerosis diagnosis

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    Detection of oligoclonal IgG bands in cerebrospinal fluid by isoelectrocfocusing and immunodetection is the current gold standard to detect an inflammatory process in the central nervous system. It has been proposed that the presence of free light chains (FLCs) in CSF was associated with recent demyelination activity in MS and might be used as a prognosis marker. Our study’s objective is assessing the diagnostic accuracy of a new highly sensitive latex-enhanced nephelometric assay for k free light chain (kFLC) determination in CSF/serum as an alternative to traditional tests and its clinical application. Methods. kFLCs were measured in CSF/serum pairs from 80 patients by the use of a new highly sensitive latex-enhanced nephelometric automated immunoassay for detection of immunoglobulin FLC. The eighty patients were split into three groups according to the neurological diagnosis. In this study we confirm even more the use of the k Index as a diagnostic aid in multiple sclerosis. Results. kFLC Index seems to be more accurate parameter respect the determination of oligoclonal immunoglobulin bands (OCBs). We recalculate the K Index sensitivity and specificity respect the precedent published result. Two patients previously diagnosed with leukoencephalopathy have gone to group 3 as confirmed the diagnosis of MS. Conclusions. These new data reinforce even more the use of the k Index to diagnose MS in comparison to classical methods and to the reference method, the OCBs

    ESA SENTINEL 2 IMAGERY AND GBGEOAPP: INTEGRATED TOOLS FOR THE DEOSAI NATIONAL PARK MANAGEMENT PLAN

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    Deosai plateau, in the Gilgit-Baltistan Province of Pakistan, for its average elevation of 4,114 meters, is the second highest plateau in the world after Changtang Tibetan Plateau. Two biogeographically important mountain ranges merge in Deosai: the Himalayan and Karakorum–Pamir highlands. The Deosai National Park, with its first recognition in 1993, encompasses an area of about 1620 km2, with the altitude ranging from 3500 to 5200 meters a.s.l. It is known and visited by tourists for the presence of brown bear, but a large number of species of fauna and flora leave, and can be seen during the summer season. This high-altitude ecosystem is particularly fragile and can be considered a sentinel for the effects of climate changes. Due to its geographic position and high altitude, the area of Deosai has never been studied in all its ecosystem components, producing high resolution maps. The first land cover map of Deosai with 10 meters of resolution is discussed in this study. This map has been obtained from Sentinel-2 imagery and improved through the new tool developed in this study: the GBGEOApp. This application for mobile has been done with three main ambitions: the validation of the new land cover map, its improvement with land use information, and the collection of new data in the field. On the basis of the results, the use of the GBGEOApp, as a tool for validation and increasing of environmental data collection, seems to be completely applicable involving the local technicians in a process of data sharing

    ON THE APPLICATION OF REMOTE SENSING TIME SERIES ANALYSIS FOR LAND COVER MAPPING: SPECTRAL INDICES FOR CROPS CLASSIFICATION

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    Abstract. This study aims to introduce a semi-automatic classification workflow for the production of a land use/land cover (LULC) map of the island of Sardinia (Italy) following the CORINE legend schema, and a ground spatial resolution compatible with a scale of 1:25.000. The classification is based on free high-resolution satellite imagery from Sentinel-1 and Sentinel-2 collected in 2020, ancillary data derived from Sardinian Geoportal, Joint Research Centre (JRC) and OpenStreetMap. The LULC map production includes three steps: 1) pixel-based classification, realized with two different approaches, that use i) information derived from existing thematic maps eventually re-coded in case of incoherencies observed between datasets and/or satellite data products, and ii) spectral indices and parameter thresholds defined on the basis of multitemporal analysis; 2) segmentation of Sentinel-1 and 2 annual composites, and pre-labelling of segments with the pixel-based classified map, obtaining the preliminary map; 3) visual inspection procedure in order to confirm, or re-assign, classes to polygons. The accuracy of the preliminary map was tested in a sample area and on specific class of non-irrigated crops through ground truth data collected from a detailed photo-interpretation, estimating 97% of overall accuracy. The results show a great improvement from existing thematic maps in terms of detail, with the possibility of a yearly updating of the map via automatic processes. However, some limitations were found, due to the high fragmentation of Sardinian landscape and the high variety of crop types and agricultural practices, that could affect the efficiency of the classifier

    Effect of storage conditions on seed germination of eigTyrrhenian endemic vascular plant species of conservation interest

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    The conservation of endemic and endangered plant species is of great interest to the scientific and research community. In this frame, seed banks play a crucial role when biodiversity preservation and climate change are considered. The study of seed viability and germination during storage conditions provides basic and useful information to ensure successful ex situ conservation. The aim of this study was to evaluate whether storage time and conditions (i.e., base collection at -25°C and active collection at +5°C) affect seed germination in the long term. For these purposes, eight Tyrrhenian endemic vascular plant species (mostly endangered) with orthodox seeds were studied: Brassica insularis, Centranthus amazonum, Dianthus morisianus, Digitalis purpurea var. gyspergerae, Ferula arrigonii, Helicodiceros muscivorus, Iberis integerrima and Verbascum plantagineum. These species were stored in the Sardinian Germplasm Bank (BG-SAR) at -25°C and at +5°C for a time ranging from 2 to 12 years. Germination tests were carried out following the optimal conditions reported in the literature for each species. The results showed, in general terms, the high seed germination capacity of all species stored at both conditions; regarding the time of seed storage, germination in some tested species (such as B. insularis and C. amazonum) slightly decreased over time. We argued that seed dehydration, low seed moisture content during storage and the use of hermetic glass containers can be considered key factors for long-term conservation of these orthodox seeds. In conclusion, this study showed that the conservation of these endemic species is ensured by seed bank storage, according to the general assumption that seed longevity depends on seed lot quality, on well-sealed storage containers and conditions before and during storage

    Chronic treatment with statins increases the availability of selenium in the antioxidant defence systems of hemodialysis patients.

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    Project. Oxidative stress (OS) is enhanced in hemodialysis (HD) patients. Lipid peroxidation and oxidative damage to glycids, proteins and nucleic acids are main consequences of OS and are associated to increased cardiovascular risk. Vitamin E and Glutathione Peroxidase (GSH-Px) represent main antioxidant systems in human cells. Selenium (Se), bound to the active sites of GSH-Px, plays a critical role in this antioxidant defense system. Statins are widely used and extensively investigated in the prevention of cardiovascular disease, notably in high-risk subjects. Several studies suggest that statins show antioxidant effects, protecting low-density lipoproteins from oxidation. Aim of our study was to compare serum Se concentration in ESRD patients on maintenance HD and in homogeneous healthy subjects and to investigate whether chronic assumption of statins may interfere with serum Se concentration in HD patients. Procedure. A total of 103 HD patients and 69 healthy subjects were enrolled; HD patients were then divided into patients who were not treated with statins (group A) and patients who assumed statins since six months at least (group B). Serum Se was determined by atomic absorption spectrometry. Results. Serum Se was significantly lower in HD patients of group A compared to healthy subjects (81.65±19.66mcg/L Vs. 96.47±15.62mcg/L, p<0.0040). However, in HD patients who assumed statins serum Se was significantly higher than in HD patients who did not. (111.83±18.82mcg/L Vs. 81.65±19.66mcg/L, p<0.0001). Conclusions. our results suggest that in HD patients chronic assumption of statins is related to a higher availability of active antioxidant agents and to reduced oxidative stress

    acat1 cav 1 and prp expression in brains and skin fibroblasts from sarda breed sheep with scrapie resistant and scrapie susceptible genotype

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    Scrapie is an infective ovine neurodegenerative disease; the only identified component of the infectious agent being an aberrant isoform (PrPSc) of the cellular prion protein (PrPC). So far, no means for ante-mortem diagnosis are available for Scrapie as well as for any other mammal Transmissible Spongiform Encephalopaties. We recently found a strong relationship between cell susceptibility to scrapie-infection and intracellular cholesterol homeostasis alterations. In brain tissues as well as in ex vivo cultures of skin fibroblasts and PBMCs from healthy and scrapie-affected sheep carrying a scrapie-susceptible (ARQ/ARQ) genotype, the levels of cholesterol esters were consistently higher than in tissues and cultures derived from animals with a scrapie-resistant (ARR/ARR) genotype. Moreover, both uninfected and scrapie-affected ARQ/ARQ sheep showed abnormally low levels of high density lipoprotein-cholesterol (HDL-C) in their plasma, as compared to ARR/ARR animals. We now show that intracellular accumulation of cholesterol esters in fibroblasts derived from scrapie-susceptible sheep was accompanied by parallel alterations in the expression level of genes and gene products (ACAT1 and Cav-1) that are involved in the pathways leading to intracellular cholesterol esterification and trafficking. Comparative analysis of PrPc mRNA, showed an higher expression level in cells from animals carrying susceptible genotype, with or without Scrapie. Preliminary experiments also revealed the presence of PK-resistant PrP isoforms in the latter cultures. The data reported in the present paper suggest that accumulation of cholesterol esters in peripheral cells, together with the altered expression of some proteins implicated in intracellular cholesterol homeostasis, might serve to identify a distinctive lipid metabolic profile associated with increased susceptibility to develop prion disease following infection

    RNA analysis of consensus sequence splicing mutations: implications for thediagnosis of Wilson disease

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    Wilson disease (WD) is an autosomal recessive disorder caused by a defective function of the copper-transporting ATP7B protein. This results in progressive copper overload and consequent liver, brain, and kidney damage. Approximately 300 WD-causing mutations have been described to date. Missense mutations are largely prevalent, while splice-site mutations are rarer. Of these, only a minority are detected in splicing consensus sequences. Further, few splicing mutations have been studied at the RNA level. In this study we report the RNA molecular characterization of three consensus splice-site mutations identified by DNA analysis in WD patients. One of them, c.51 + 4 A --> T, resides in the consensus sequence of the donor splice site of intron 1; the second, c. 2121 + 3 A --> G, occurred in position + 3 of intron 7; and the c.2447 + 5 G --> A is localized in the consensus sequence of the donor splice site of intron 9. Analysis revealed predominantly abnormal splicing in the samples carrying mutations compared to the normal controls. These results strongly suggest that consensus sequence splice-site mutations result in disease by interfering with the production of the normal WD protein. Our data contribute to understanding the mutational spectrum that affect splicing and improve our capability in WD diagnosis

    In vitro synergistic anti-prion effect of cholesterol ester modulators in combination with chlorpromazine and quinacrine

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    Abstract Our studies on the role of cholesterol in prion infection/replication showed that brains and peripheral cells of sheep susceptible-to or suffering-from Scrapie were characterized by an altered cholesterol homeostasis, and that drugs affecting cholesterol ester pool were endowed with selective anti-prion activity in N2a cell lines infected with the 22L and RML prion strains. In these prion-infected N2a cell lines, we now report increased anti-prion activity of dual-drug combinations consisting of cholesterol ester modulators associated with prion inhibitors. Synergism was obtained with the cholesterol ester modulators everolimus, pioglitazone, progesterone, and verapamil associated with the anti-prion chlorpromazine, and with everolimus and pioglitazone associated with the anti-prion quinacrine. In addition, comparative lipid analyses in prion-infected vs. uninfected N2a cells, demonstrated a derangement of type and distribution of cholesterol ester, free cholesterol, and triglyceride pools in the infected cells. Single-drug treatments differently affected synthesis of the various lipid forms, whereas combined drug treatments appeared to restore a lipid profile similar to that of the untreated-uninfected cells. We conclude that the anti-prion synergistic effects of cholesterol ester modulators associated with the cholesterol-interfering anti-prion drugs chlorpromazine and quinacrine may arise from the ability of combined drugs to re-establish lipid homeostasis in the prion-infected cells. Overall, these data suggest that inhibition of prion replication can be readily potentiated by combinatorial drug treatments and that steps of cholesterol/cholesterol ester metabolism may represent suitable targets
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