343 research outputs found
Automatic Patient Modeling for Hyperthermia Treatment Planning of Head and Neck Cancer
Head and neck (H&N) cancer is the term used to describe a wide range of malig-
nant tumors originating in the upper airways and swallowing tracts. In 2012,
this disease accounted for approximately 5% of all cancers worldwide, with
680,000 new cases diagnosed and 370,000 recorded deaths, resulting as the seventh
most common cancer worldwide. The H&N region is often divided in subregions
containing dfferent tumor sites, as depicted in Figure 1.1: the oral cavity, paranasal
sinus and nasal cavity, salivary glands, nasopharynx, oropharynx, hypopharynx (bot-
tom part of the throat) and larynx. Tumors in the eyes, brain and skin are generally
not considered H&N cancer
âConvergenze e sinergie tra traduzione e studi comparati: una rassegna criticaâ
L'articolo propone un'analisi dell'attuale dibattito su studi traduttori e letterature transnazionali-World literatur
Integrability and strong normal forms for non-autonomous systems in a neighbourhood of an equilibrium
The paper deals with the problem of existence of a convergent "strong" normal
form in the neighbourhood of an equilibrium, for a finite dimensional system of
differential equations with analytic and time-dependent non-linear term. The
problem can be solved either under some non-resonance hypotheses on the
spectrum of the linear part or if the non-linear term is assumed to be (slowly)
decaying in time. This paper "completes" a pioneering work of Pustil'nikov in
which, despite under weaker non-resonance hypotheses, the nonlinearity is
required to be asymptotically autonomous. The result is obtained as a
consequence of the existence of a strong normal form for a suitable class of
real-analytic Hamiltonians with non-autonomous perturbations.Comment: 10 page
Persistence of Diophantine flows for quadratic nearly-integrable Hamiltonians under slowly decaying aperiodic time dependence
The aim of this paper is to prove a Kolmogorov-type result for a
nearly-integrable Hamiltonian, quadratic in the actions, with an aperiodic time
dependence. The existence of a torus with a prefixed Diophantine frequency is
shown in the forced system, provided that the perturbation is real-analytic and
(exponentially) decaying with time. The advantage consists of the possibility
to choose an arbitrarily small decaying coefficient, consistently with the
perturbation size.Comment: Several corrections in the proof with respect to the previous
version. Main statement unchange
Normal Form and Nekhoroshev stability for nearly-integrable Hamiltonian systems with unconditionally slow aperiodic time dependence
The aim of this paper is to extend the results of Giorgilli and Zehnder for
aperiodic time dependent systems to a case of general nearly-integrable convex
analytic Hamiltonians. The existence of a normal form and then a stability
result are shown in the case of a slow aperiodic time dependence that, under
some smallness conditions, is independent on the size of the perturbation.Comment: Corrected typo in the title and statement of Lemma 3.
[68Ga]Ga-DOTANOC Uptake at Pancreatic Head/Uncinate Process: Is It a Persistent Diagnostic Pitfall Over Time?
Simple Summary The purpose of the present study is to describe the frequency of non-malignant [68Ga]Ga-DOTANOC uncinate process (UP) uptake and to evaluate its variations over time. Among the first 6 months of enrolment of a monocentric prospective observational electronic archive, analyses of a large number of PET/CT scans (n = 268) of NEN pts (n = 172) demonstrated that: UP uptake is a frequent finding (observed in almost half of the cases, slightly higher than previously reported), mostly presenting with a diffuse pattern and, interestingly, characterized by variations over time in almost one third of the cases. The consciousness of this diagnostic pitfall is of utmost importance for accurate [68Ga]Ga-DOTANOC PET/CT reporting, since the pancreas represents one of the most frequent sites of NEN. Purpose: [68Ga]Ga-DOTA-peptide uptake in the pancreatic head/uncinate process (UP) is a frequent PET/CT finding. Although mostly physiologic, it can represent a pitfall in PET/CT reading, especially when focal. An increased frequency of UP uptake has been reported in patients (pts) affected by diabetes mellitus (DM). The aim of the study is to describe the frequency of [68Ga]Ga-DOTANOC UP uptake to evaluate its variations over time and its possible correlation with DM. Methods: In September 2017, a monocentric prospective observational electronic archive was initiated at our center to collect clinical and imaging data of pts undergoing [68Ga]Ga-DOTANOC PET/CT. Among the pts enrolled in the first 6 months (Sept 2017 to Feb 2018), those presenting [68Ga]Ga-DOTANOC PET/CT uptake at UP level were included. Pts with UP lesions already documented on CT/MRI or those that underwent surgical excision of UP before PET/CT were excluded from the analysis. [68Ga]Ga-DOTANOC UP uptake was classified as diffuse or focal and compared with the pattern observed in previous PET/CT scans performed at our center. An increased frequency of UP uptake was also correlated with the presence of DM. Results: In the first 6 months, 253 pts were enrolled in the archive and 172 out of them were included in the analysis. UP increased uptake was frequently observed (77/172, 44.8%) and was mostly diffuse (62/77). In 75/172 pts (43.6%), previous [68Ga]Ga-DOTANOC PET/CT scans were available (overall 268 scans; number of previous PET per pt range: 1-20) and were retrospectively reviewed. Despite the fact that, in most pts, the uptake pattern was stable over time (54/75 pts, 72%), it changed in approximately one third of cases (21/75, 28%). Among DM pts (29/172), only 10/29 (34.4%) presented increased UP uptake. Conclusions: UP [68Ga]Ga-DOTANOC uptake is a frequent non-malignant finding (slightly higher than previously reported), mostly presenting with a diffuse pattern. However, contrary to previous reports, our data show that the pattern of uptake may vary over time in approximately one third of the cases and it is not more frequently observed in pts with DM
Feasibility and relevance of discrete vasculature modeling in routine hyperthermia treatment planning
Purpose: To investigate the effect of patient specific vessel cooling on head and neck hyperthermia treatment planning (HTP). Methods and materials: Twelve patients undergoing radiotherapy were scanned using computed tomography (CT), magnetic resonance imaging (MRI) and contrast enhanced MR angiography (CEMRA). 3D patient models were constructed using the CT and MRI data. The arterial vessel tree was constructed from the MRA images using the âgraph-cutâ method, combining information from Frangi vesselness filtering and region growing, and the results were validated against manually placed markers in/outside the vessels. Patient specific HTP was performed and the change in thermal distribution prediction caused by arterial cooling was evaluated by adding discrete vasculature (DIVA) modeling to the Pennes bioheat equation (PBHE). Results: Inclusion of arterial cooling showed a relevant impact, i.e., DIVA modeling predicts a decreased treatment quality by on average 0.19 °C (T90), 0.32 °C (T50) and 0.35 °C (T20) that is robust against variations in the inflow blood rate (|ÎT| 0.5 °C) were observed. Conclusion: Addition of patient-specific DIVA into the thermal modeling can significantly change predicted treatment quality. In cases where clinically detectable vessels pass the heated region, we advise to perform DIVA modeling
radionuclides behavior in fruit plants
This paper summarizes research carried out on fruits by the Universita Cattolica del Sacro Cuore (UCSC) in Piacenza, Italy. Among the fruit crops studied, strawberry, blackberry, grapevine, apple, pear, and olive, research on strawberry and blackberry was funded by the Food Standard Agency (UK). Fruit plants were grown in pots, kept under tunnels or in open field, and contaminated with 134Cs and 85Sr via leaves or via soil. Interception in strawberry plants ranges 39â17 % for 134Cs, from anthesis (April) to predormancy (November). Leaf-to-fruit translocation occurs to a greater extent for 134Cs than for 85Sr. The distribution of contamination in fruit crops is an element-specific process: 134Cs is preferentially allocated to fruits and 85Sr to leaves. However, the activity in leaves is also species-specific: fruit species show different leaf-to-fruit translocation. Results on apple, pear, and grape crops indicate that the highest transfer from leaf to fruit occurs in apple crops. Olive plants also show 134Cs translocation from leaves to trunks. Grapevines grown on mineral soil show a root uptake higher for 85Sr than for 134Cs, while strawberries grown on a peat substrate show a root uptake higher for 134Cs than for 85Sr. Rinsing directly contaminated fruits removes 85Sr (36 %) to a greater degree than 134Cs (24 %). Transfer to olive oil is low. A 57 % of 134Cs is transferred from grapes to white wine
Affective economies, pandas, and the atmospheric politics of lively capital
This paper is concerned with the affective economies of lively capital. Its central argument is that nonhuman life itself has become a locus of accumulation, marked by an atmospheric politics of capital: the intensification of relations between life and productivity by incorporating entire lifeworlds into regimes of generating value. Focusing on the Giant panda â a spectacular icon raising millions of dollars globally â the paper first examines junctures at which their charismatic affects emerge and are manipulated to produce value. Turning to panda lifeworlds in zoos, it then shows how such value production is contingent upon affective labours nonhumans perform in captivity. Nonhuman labour, as a component of atmospheric politics, enables understanding how lively capital is produced and reproduced, a theme interrogated through a critical analysis of the commercial global circulation of pandas. The paper develops the concept of atmospheric politics â an intervention in an animalâs milieu and its affective intensities â as a means for analyzing the dynamics of lively capital. Atmospheric politics retrieves a critical political economy obscured by the concept of nonhuman charisma, and restages biopower as an apparatus and political technology of capital.Parts of the research conducted for this paper was enabled by a British
Academy Postdoctoral Fellowship (Award No. pf140038)
The gendered impact of the financial crisis:Struggles over social reproduction in Greece
The global financial crisis has triggered a dramatic transformation of employment in the weakest Eurozone economies. This is evidenced in deteriorating work conditions, limited employee negotiating power, low pay, zero-hours contracts and, most importantly, periods of prolonged unemployment for most of the working population, especially women. We offer a critical analysis of the boundaries of formal and informal, paid and unpaid, productive and reproductive work, and explore how austerity policies implemented in Greece in the aftermath of the global financial crisis have transformed womenâs everyday lives. In contributing to critical discussions of neoliberal capitalism and recent feminist geography studies, our empirical study focuses on how womenâs struggles over social reproduction unfold in the public and private spheres. It proposes that womenâs temporary retreat to unpaid work at home constitutes a form of resistance to intensifying precarisation, and, at times, contributes to the emergence of new collective forms of reproduction.</p
- âŠ