297 research outputs found
CREATION OF A MULTIRESOLUTION AND MULTIACCURACY DTM: PROBLEMS AND SOLUTIONS FOR HELI-DEM CASE STUDY
The work is part of "HELI-DEM" (HELvetia-Italy Digital Elevation Model) project, funded by the European Regional Development Fund within the Italy-Switzerland cooperation program. The aim of the project is the creation of a unique DTM for the alpine and subalpine area between Italy (Piedmont, Lombardy) and Switzerland (Ticino and Grisons Cantons); at present, different DTMs, that are in different reference frames and have been obtained with different technologies, accuracies, and resolutions, have been acquired. The final DTM should be correctly georeferenced and produced validating and integrating the data that are available for the project. DTMs are fundamental in hydrogeological studies, especially in alpine areas where hydrogeological risks may exist. Moreover, when an event, like for example a landslide, happens at the border between countries, a unique and integrated DTM which covers the interest area is useful to analyze the scenario. In this sense, HELI-DEM project is helpful. To perform analyses along the borders between countries, transnational geographic information is needed: a transnational DTM can be obtained by merging regional low resolution DTMs. Moreover high resolution local DTMs should be used where they are available. To be merged, low and high resolution DTMs should be in the same three dimensional reference frame, should not present biases and should be consistent in the overlapping areas. Cross-validation between the different DTMs is therefore needed. Two different problems should be solved: the merging of regional, partly overlapping low and medium resolution DTMs into a unique low/medium resolution DTM and the merging with other local high resolution/high accuracy height data. This paper discusses the preliminary processing of the data for the fusion of low and high resolution DTMs in a study-case area within the Lombardy region: Valtellina valley. In this region the Lombardy regional low resolution DTM is available, with a horizontal resolution of 20 meters; in addition a LiDAR DTM with a horizontal resolution of 1 meter, which covers only the main hydrographic basins, is also available. The two DTMs have been transformed into the same reference frame. The cross-validation of the two datasets has been performed comparing the low resolution DTM with the local high resolution DTM. Then, where significant differences are present, GPS survey have been used as external validation. The results are presented. Moreover, a possible strategy for the future fusion of the data, is shortly summarized at the end of the paper
A semi-implicit, second-order-accurate numerical model for multiphase underexpanded volcanic jets
Abstract. An improved version of the PDAC (Pyroclastic Dispersal Analysis Code, Esposti Ongaro et al., 2007) numerical model for the simulation of multiphase volcanic flows is presented and validated for the simulation of multiphase volcanic jets in supersonic regimes. The present version of PDAC includes second-order time- and space discretizations and fully multidimensional advection discretizations in order to reduce numerical diffusion and enhance the accuracy of the original model. The model is tested on the problem of jet decompression in both two and three dimensions. For homogeneous jets, numerical results are consistent with experimental results at the laboratory scale (Lewis and Carlson, 1964). For nonequilibrium gasâparticle jets, we consider monodisperse and bidisperse mixtures, and we quantify nonequilibrium effects in terms of the ratio between the particle relaxation time and a characteristic jet timescale. For coarse particles and low particle load, numerical simulations well reproduce laboratory experiments and numerical simulations carried out with an EulerianâLagrangian model (Sommerfeld, 1993). At the volcanic scale, we consider steady-state conditions associated with the development of Vulcanian and sub-Plinian eruptions. For the finest particles produced in these regimes, we demonstrate that the solid phase is in mechanical and thermal equilibrium with the gas phase and that the jet decompression structure is well described by a pseudogas model (Ogden et al., 2008). Coarse particles, on the other hand, display significant nonequilibrium effects, which associated with their larger relaxation time. Deviations from the equilibrium regime, with maximum velocity and temperature differences on the order of 150 m sâ1 and 80 K across shock waves, occur especially during the rapid acceleration phases, and are able to modify substantially the jet dynamics with respect to the homogeneous case
Dual-layer spectral CT fusion imaging for lung biopsies: more accurate targets, diagnostic samplings, and biomarker information?
The increasingly widespread use of computed tomography (CT) has increased the number of detected lung lesions, which are then subjected to needle biopsy to obtain histopathological diagnosis. Obtaining high-quality biopsy specimens is fundamental for diagnosis and biomolecular characterisation that guide therapy decision-making. In order to obtain samples with high diagnostic potential, fusion imaging techniques, such as fusion between positron emission tomography and CT, have been introduced to target the biopsy where there more viable neoplastic cells can be sampled. Nowadays, dual-layer spectral CT represents a novel technology enabling an increased tissue characterisation. In particular, Z-effective images, i.e., colour-coded images based on the effective atomic number of tissue components, provide a higher level of discrimination than usual imaged based on x-ray attenuation in Hounsfield units and offer the potential of a better tissue characterisation. Our hypothesis is based on the future use of data provided by spectral CT, in particular by Z-effective images, as a guide for appropriate biopsy sampling for histopathological and biomolecular characterisation in the era of patient tailored-therapy
Pocket-sized, wireless-Bluetooth ultrasound system to perform diagnostic and low-complexity interventional procedures in bedridden patients during the COVID-19 pandemic: from intensive care unit to domiciliary service?
The use of a pocked-sized, wireless-Bluetooth ultrasound portable system with display images presented on a tablet facilitated the work of our radiologists during the first wave of coronavirus disease 2019 (COVID-19) to perform diagnostic and interventional procedures in bedridden patients. The device is equipped with a battery-powered probe without cables that transmits images to a tablet (or a cell phone) through a dedicated App. We hypothesise in future to extend diagnostic and low-complexity interventional procedures from hospitalised patients to at-home patients who are not able to mobilise out of bed or are difficult to transport. This domiciliary service might also reduce the overhead of hospital accesses
Quaternary capable folds and seismic hazard in Lombardia (Northern Italy): the Castenedolo structure near Brescia.
We identify evidence of late Quaternary compressive tectonics
in the Northern sector of the Central Po Plain through a systematic
revision of the literature, new field mapping, and a new study of
seismic reflection data obtained by ENI E&P. In particular, the reinterpretation
of ca. 18.000 km of seismic profiles clearly shows a belt
of segmented, 10 to 20 km long, fault propagation folds, controlled
by the Plio-Quaternary growth of several out-of-sequence thrusts. As
an example of this active structural style, in this paper we focus on a
buried fold located just south of the Castenedolo Hill, a few km SE
of Brescia. Although the Castenedolo anticline has long ago been
described as a young compressional structure (e.g., DESIO, 1965), no
detailed structural analysis of this feature has been performed until
now. We calculated the uplift rates of this fold through the analysis
of its syntectonic sedimentary record as imaged by the extremely
high quality ENI E&P subsurface data available in the area. The evolution
of this anticline was a discontinuous process characterized by
several tectonic uplift pulses (with rates of ca. 0.1 mm/yr) of different
duration, separated by periods of variable extent in which no
fold growth occurred. The Quaternary growth history of this anticline
and the presence of faulted and folded late Pleistocene to
Holocene deposits at nearby sites (Ciliverghe and Monte Netto)
demonstrate that the significant seismicity of this area (e.g., the
December 25, 1222, Io = IX MCS Brescia earthquake, MAGRI &
MOLIN, 1986; GUIDOBONI, 1986) must be related to active compressional
structures within the Brescia piedmont belt. Our
regional investigations show that the structural and paleoseismic
setting illustrated near Castenedolo is typical of the whole Lombardia
domain of the Southern Alps. This implies that the currently
accepted seismotectonic model for this region, and related
seismic hazard assessment, should be thoroughly and carefully
re-evaluated
Successful endovascular management with a covered stent of an external iliac pseudoaneurysm following allograft nephrectomy using CO 2 as contrast medium: a case report.
Iodinated contrast agents for angiography in chronic kidney disease (CKD) patients could further deteriorate their renal function leading to adverse sequelae. The use of carbon dioxide (CO2) is reported in the literature and has been safely used for a variety of angiographic procedures, particularly to guide aortic and renal interventions. We report the case of the successful endovascular treatment with a covered stent of a right external iliac artery pseudoaneurysm following graft nephrectomy in a CKD patient, using CO2 as contrast medium
Innovative Experimental Ultrasound and US-Related Techniques Using the Murine Model in Pancreatic Ductal Adenocarcinoma: A Systematic Review
Pancreatic ductal adenocarcinoma (PDAC) is a cancer with one of the highest mortality rates in the world. Several studies have been conductedusing preclinical experiments in mice to find new therapeutic strategies. Experimental ultrasound, in expert hands, is a safe, multifaceted, and relatively not-expensive device that helps researchers in several ways. In this systematic review, we propose a summary of the applications of ultrasonography in a preclinical mouse model of PDAC. Eighty-eight studies met our inclusion criteria. The included studies could be divided into seven main topics: ultrasound in pancreatic cancer diagnosis and progression (n: 21); dynamic contrast-enhanced ultrasound (DCE-US) (n: 5); microbubble ultra-sound-mediated drug delivery; focused ultrasound (n: 23); sonodynamic therapy (SDT) (n: 7); harmonic motion elastography (HME) and shear wave elastography (SWE) (n: 6); ultrasound-guided procedures (n: 9). In six cases, the articles fit into two or more sections. In conclusion, ultrasound can be a really useful, eclectic, and ductile tool in different diagnostic areas, not only regarding diagnosis but also in therapy, pharmacological and interventional treatment, and follow-up. All these multiple possibilities of use certainly represent a good starting point for the effective and wide use of murine ultrasonography in the study and comprehensive evaluation of pancreatic cancer
Non-adhesive liquid embolic agents in extra-cranial district: State of the art and review of the literature
This review focuses on the use of ânewâ generation of non-adhesive liquid embolic agents (NALEA). In literature, non-adhesive liquid embolic agents have mainly been used in the cerebral district; however, multiple papers describing the use of NALEA in the extracranial district have been published recently and the aim of this review is to explore and analyze this field of application. There are a few NALEA liquids such as Onyx, Squid, and Phil currently available in the market, and they are used in the following applications: mainly arteriovenous malformations, endoleaks, visceral aneurysm or pseudoaneurysm, presurgical and hypervascular lesions embolization, and a niche of percutaneous approaches. These types of embolizing fluids can be used alone or in combination with other embolizing agents (such as coils or particles) so as to enhance its embolizing effect or improve its possible defects. The primary purpose of this paper is to evaluate the use of NALEAs, predominantly used alone, in elective embolization procedures. We did not attempt a meta-analysis due to the data heterogeneity, high number of case reports, and the lack of a consistent follow-up time period
Peyronie's disease development and management in diabetic men
Background: Peyronie's disease (PD) is a fibrosing disorder of the penis resulting in plaque formation and penile deformity that negatively affect sexual and psychosocial function of patients. A multifactorial etiology of PD is assumed with diabetes mellitus (DM) being a potential risk factor. Objectives: The aim of this narrative review was to investigate diabetes role in PD pathophysiology, diagnosis, and treatment. Materials and methods: A non-systematic narrative review of original articles, meta-analyses, and randomized trials was conducted, including articles in the pre-clinical setting to support relevant findings. Results: Diabetes is one of the most common comorbidity observed in PD patients, with a prevalence of about 11% and a strong association with erectile dysfunction (ED). DM is associated with both a higher risk of developing PD and has also an impact on the outcomes of PD's treatments. Discussion: Evidence from literature underlines that metabolic alterations typical of DM are pivotal factors in the development of PD and resistance to its medical treatment. Conclusion: The role of DM in development of PD is still debated, while its role in PD development is not completely clear, there is a clear impact of DM on PD treatment outcomes
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