Image-guided neurosurgery allows surgeons to view their tools in relation to preoperatively acquired patient images and models. To continue using neuronavigation systems throughout operations, image ...registration between preoperative images typically magnetic resonance imaging (MRI) and intraoperative images (e.g., ultrasound) is common to account for brain shift (deformations of the brain during surgery). We implemented a method to estimate MRI-ultrasound registration errors, with the goal of enabling surgeons to quantitatively assess the performance of linear or nonlinear registrations. To the best of our knowledge, this is the first dense error estimating algorithm applied to multimodal image registrations. The algorithm is based on a previously proposed sliding-window convolutional neural network that operates on a voxelwise basis. To create training data where the true registration error is known, simulated ultrasound images were created from preoperative MRI images and artificially deformed. The model was evaluated on artificially deformed simulated ultrasound data and real ultrasound data with manually annotated landmark points. The model achieved a mean absolute error (MAE) of 0.977 ± 0.988 mm and a correlation of 0.8 ± 0.062 on the simulated ultrasound data, and an MAE of 2.24 ± 1.89 mm and a correlation of 0.246 on the real ultrasound data. We discuss concrete areas to improve the results on real ultrasound data. Our progress lays the foundation for future developments and ultimately implementation of clinical neuronavigation systems.
ABSTRACT
Blazars research is one of the hot topics of contemporary extragalactic astrophysics. That is because these sources are the most abundant type of extragalactic γ-ray sources and are ...suspected to play a central role in multimessenger astrophysics. We have used Swift$\_$xrtproc, a tool to carry out an accurate spectral and photometric analysis of the Swift-XRT data of all blazars observed by Swift at least 50 times between December 2004 and the end of 2020. We present a database of X-ray spectra, best-fit parameter values, count rates and flux estimations in several energy bands of over 31 000 X-ray observations and single snapshots of 65 blazars. The results of the X-ray analysis have been combined with other multifrequency archival data to assemble the broad-band Spectral Energy Distributions (SEDs) and the long-term light curves of all sources in the sample. Our study shows that large X-ray luminosity variability on different time-scales is present in all objects. Spectral changes are also frequently observed with a ‘harder-when-brighter’ or ‘softer-when-brighter’ behaviour depending on the SED type of the blazars. The peak energy of the synchrotron component (νpeak) in the SED of HBL blazars, estimated from the log-parabolic shape of their X-ray spectra, also exhibits very large changes in the same source, spanning a range of over two orders of magnitude in Mrk421 and Mrk501, the objects with the best data sets in our sample.
Calderas are collapse structures related to the emptying of magmatic reservoirs, often associated with large eruptions from long-lived magmatic systems. Understanding how magma is transferred from a ...magma reservoir to the surface before eruptions is a major challenge. Here we exploit the historical, archaeological and geological record of Campi Flegrei caldera to estimate the surface deformation preceding the Monte Nuovo eruption and investigate the shallow magma transfer. Our data suggest a progressive magma accumulation from ~1251 to 1536 in a 4.6 ± 0.9 km deep source below the caldera centre, and its transfer, between 1536 and 1538, to a 3.8 ± 0.6 km deep magmatic source ~4 km NW of the caldera centre, below Monte Nuovo; this peripheral source fed the eruption through a shallower source, 0.4 ± 0.3 km deep. This is the first reconstruction of pre-eruptive magma transfer at Campi Flegrei and corroborates the existence of a stationary oblate source, below the caldera centre, that has been feeding lateral eruptions for the last ~5 ka. Our results suggest: 1) repeated emplacement of magma through intrusions below the caldera centre; 2) occasional lateral transfer of magma feeding non-central eruptions within the caldera. Comparison with historical unrest at calderas worldwide suggests that this behavior is common.
The self is the core of our mental life. Previous investigations have demonstrated a strong neural overlap between self‐related activity and resting state activity. This suggests that information ...about self‐relatedness is encoded in our brain's spontaneous activity. The exact neuronal mechanisms of such “rest‐self containment,” however, remain unclear. The present EEG study investigated temporal measures of resting state EEG to relate them to self‐consciousness. This was obtained with the self‐consciousness scale (SCS) which measures Private, Public, and Social dimensions of self. We demonstrate positive correlations between Private self‐consciousness and three temporal measures of resting state activity: scale‐free activity as indexed by the power‐law exponent (PLE), the auto‐correlation window (ACW), and modulation index (MI). Specifically, higher PLE, longer ACW, and stronger MI were related to higher degrees of Private self‐consciousness. Finally, conducting eLORETA for spatial tomography, we found significant correlation of Private self‐consciousness with activity in cortical midline structures such as the perigenual anterior cingulate cortex and posterior cingulate cortex. These results were reinforced with a data‐driven analysis; a machine learning algorithm accurately predicted an individual as having a “high” or “low” Private self‐consciousness score based on these measures of the brain's spatiotemporal structure. In conclusion, our results demonstrate that Private self‐consciousness is related to the temporal structure of resting state activity as featured by temporal nestedness (PLE), temporal continuity (ACW), and temporal integration (MI). Our results support the hypothesis that self‐related information is temporally contained in the brain's resting state. “Rest‐self containment” can thus be featured by a temporal signature.
The number of elderly patients diagnosed with hepatocellular carcinoma (HCC) is expected to increase. We compared the presenting features and outcome of HCC in elderly (>or=70 years) and younger ...patients (<70 years).
Multicentre retrospective cohort study and nested case-control study. Patients 614 elderly and 1104 younger patients from the ITA.LI.CA database, including 1834 HCC cases consecutively diagnosed from January 1987 to December 2004. Both groups were stratified according to treatment: hepatic resection, percutaneous procedures, transarterial chemoembolisation (TACE). Survival was assessed in the whole population and in each treatment subgroup. Age, sex, aetiology, cirrhosis, comorbidities and cancer stage (CLIP score) were tested as predictors of survival. In each subgroup, differences in patient survival were also assessed after adjustment and matching by propensity score.
Ageing was associated with a higher prevalence of comorbidities, better liver function and CLIP score. Regardless of age, two-thirds of patients underwent radical treatments or TACE. Elderly patients underwent more ablative procedures and fewer resections or TACE sessions. The survival of elderly and younger patients was comparable in each treatment subset, and was predicted by CLIP score. This result was confirmed by the propensity analysis.
The overall applicability of radical or effective HCC treatments was unaffected by old age. However, treatment distribution differed, elderly individuals being more frequently treated with percutaneous procedures and less frequently with resection or TACE. Survival was unaffected by age and primarily predicted by cancer stage, assessed by the CLIP system, both in the overall population and in treatment subgroups.
In this paper we investigate the computational power of a set of mobile robots with limited visibility. At each iteration, a robot takes a snapshot of its surroundings, uses the snapshot to compute a ...destination point, and it moves toward its destination. Robots are punctiform and memoryless, they operate in
R
m
, they have local reference systems independent of each other, and are activated asynchronously by an adversarial scheduler. Moreover, robots are non-rigid, in that they may be stopped by the scheduler at each move before reaching their destination (but are guaranteed to travel at least a fixed unknown distance before being stopped). We show that despite these strong limitations, it is possible to arrange
3
m
+
3
k
of these weak entities in
R
m
to simulate the behavior of a stronger robot that is rigid (i.e., it always reaches its destination) and is endowed with
k
registers of persistent memory, each of which can store a real number. We call this arrangement a
TuringMobile
. In its simplest form, a TuringMobile consisting of only three robots can travel in the plane and store and update a single real number. We also prove that this task is impossible with fewer than three robots. Among the applications of the TuringMobile, we focused on Near-Gathering (all robots have to gather in a small-enough disk) and Pattern Formation (of which Gathering is a special case) with limited visibility. Interestingly, our investigation implies that both problems are solvable in Euclidean spaces of any dimension, even if the visibility graph of the robots is initially disconnected, provided that a small amount of these robots are arranged to form a TuringMobile. In the special case of the plane, a basic TuringMobile of only three robots is sufficient.
Palmar-plantar erythrodysesthesia (PPE), also called hand-foot syndrome or hand-to-foot syndrome, is a distinctive and relatively frequent dermatologic toxic reaction associated with certain ...chemotherapeutic agents. Pegylated liposomal doxorubicin (PLD), a long-circulating formulation of doxorubicin in which doxorubicin hydrochloride is encapsulated within pegylated liposomes, is approved to treat patients with metastatic breast cancer, advanced ovarian cancer, and acquired immunodeficiency syndrome-related Kaposi's sarcoma. The incidence of PPE is increased in patients receiving PLD compared with conventional doxorubicin. In studies that utilized the currently approved dose of PLD (50 mg/m2 every 4 weeks), ∼50% of all patients receiving PLD experienced PPE, and ∼20% experienced grade 3 PPE. The pathophysiology of PPE, as it occurs with any drug with which it is associated, is not well understood. Studies evaluating the development of PPE specifically associated with PLD have not fully elucidated the mechanism; however, data support the roles of drug excretion in sweat and local pressure as contributors. When PPE develops, clinical interventions with respect to altering PLD administration include dose reduction, less frequent dosing, and ultimately, drug withdrawal with several consequences on treatment efficacy. This article will review the available data regarding the etiology and potential management strategies of PPE associated with PLD.
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