138 research outputs found

    Towards a P Systems Normal Form Preserving Step-by-step Behavior

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    Starting from a compositional operational semantics of transition P Systems we have previously defined, we face the problem of developing an axiomatization that is sound and complete with respect to some behavioural equivalence. To achieve this goal, we propose to transform the systems into a unique normal form which preserves the semantics. As a first step, we introduce axioms which allow the transformation of mem- brane structures with no dissolving rules into flat membranes. We discuss the problems which arise when dissolving rules are allowed and we suggest possible solutions. We leave as future work the further step that leads to the wanted normal form

    Cardiac metastasis presenting with an ischaemic electrocardiogram pattern mimicking anterior myocardial infarction

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    A cardiacmetastasis from a squamous cell carcinoma of the nasal cavities presented with an electrocardiogram showing ST-segment elevation and T-waves inversion in the anterior leads

    Sudden death after valve-in-valve procedure due to delayed coronary obstruction: A case report

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    Background: Valve-in-valve transcatheter aortic valve implantation for degenerated aortic bioprostheses is an effective option for patients at high risk for redo surgery, even if it may be burdened by complications more common in specific settings, such as, coronary artery obstruction. Case presentation: We present the case of a Caucasic 84-year-old woman with degeneration of a previously implanted aortic Mitroflow bioprosthesis. She underwent a valve-in-valve transcatheter aortic valve implantation with a CoreValve\uae bioprosthesis. End-procedure coronary angiography demonstrated maintained perfusion of both coronary arteries. However, few hours later, she experienced sudden cardiac death. An autopsy showed that Mitroflow prosthesis leaflets were higher than the left main coronary ostium, and no other possible cause for the sudden death. Fatality was thus ascribed to left main coronary ostium obstruction due to apposition of the Mitroflow leaflet pushed upward by the late expansion of CoreValve\uae. Conclusions: Coronary artery obstruction is a frequently fatal complication which usually presents just after valve implantation, but, as reported in our case, it may also have a delayed presentation. Accurate patient's selection and intraoperative preventive measures can reduce this eventuality

    The Cluster Distribution as a Test of Dark Matter Models. III. the Cluster Velocity Field

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    We study the large-scale velocity fields traced by galaxy clusters in numerical simulations of a box of side 960 h1h^{-1} Mpc, and compare them with available data on real clusters. In order to test the reliability of the simulations, which are based on an optimized version of the Zel'dovich approximation, we compare their cluster velocities with those of "exact" N-body simulations, and find a remarkable agreement between the two according to a variety of statistical tests. We analyse Cold Dark Matter models with density parameter in the range 0.2Ω010.2\le \Omega_0\le 1, both with and without the cosmological constant term to provide a flat geometry. We also simulate a Cold+Hot Dark Matter model, with 30% provided by the hot component. Comparison with real data is performed by applying tests based on the cumulative velocity frequency distribution (CVFD) and bulk flow statistics. For the CVFD, we use observational velocity data from different authors. By merging all available data in a combined sample, the CVFD test is able to exclude only open models with Ω00.4\Omega_0\le 0.4 and flat models with Ω0=0.2\Omega_0=0.2. However, the analysis of individual observational samples gives contradictory results; in particular the recent Giovanelli data, which imply much lower velocities (with significantly smaller uncertainties) than the other data, are actually only consistent with the open Ω0=0.4\Omega_0=0.4 and the flat Ω0=0.2\Omega_0=0.2 models, i.e. the models which are excluded by the other data. Furthermore, CVFD and bulk flow analyses of the Branchini et al. reconstructed velocity data disfavour precisely those models accepted on the grounds of Giovanelli's sample. Finally, we confirm that the Lauer & Postman bulk flow determination is an extremely rare event in the cosmological models we have analysed.Comment: 18 pages in Latex using MN.sty + 7 figures in an additional file, submitted to MNRA

    Single-isocenter multiple-target stereotactic radiosurgery for multiple brain metastases: dosimetric evaluation of two automated treatment planning systems

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    Purpose Automated treatment planning systems are available for linear accelerator (linac)-based single-isocenter multi-target (SIMT) stereotactic radiosurgery (SRS) of brain metastases. In this study, we compared plan quality between Brainlab Elements Multiple Brain Metastases (Elements MBM) software which utilizes dynamic conformal arc therapy (DCAT) and Varian HyperArc (HA) software using a volumetric modulated arc therapy (VMAT) technique. Patients and methods Between July 2018 and April 2021, 36 consecutive patients >= 18 years old with 367 metastases who received SIMT SRS at UPMC Hillman Cancer San Pietro Hospital, Rome, were retrospectively evaluated. SRS plans were created using the commercial software Elements MBM SRS (Version 1.5 and 2.0). Median cumulative gross tumor volume (GTV) and planning tumor volume (PTV) were 1.33 cm(3) and 3.42 cm(3), respectively. All patients were replanned using HA automated software. Extracted dosimetric parameters included mean dose (D-mean) to the healthy brain, volumes of the healthy brain receiving more than 5, 8,10, and 12 Gy (V-5Gy, V-8Gy, V-10Gy and V-12Gy), and doses to hippocampi. Results Both techniques resulted in high-quality treatment plans, although Element MBM DCAT plans performed significantly better than HA VMAT plans, especially in cases of more than 10 lesions). Median V-12Gy was 13.6 (range, 1.87-45.9) cm(3) for DCAT plans and 18.5 (2.2-62,3) cm(3) for VMAT plans (p < 0.0001), respectively. Similarly, V-10Gy, V-8Gy, V-5Gy (p < 0.0001) and median dose to the normal brain (p = 0.0001) were favorable for DCAT plans. Conclusions Both Elements MBM and HA systems were able to generate high-quality plans in patients with up to 25 brain metastases. DCAT plans performed better in terms of normal brain sparing, especially in patients with more than ten lesions and limited total tumor volume

    Anterior mitral valve aneurysm is an uncommon complication of aortic valve infective endocarditis: A case report

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    Objective: Rare disease Background: Mitral valve aneurysms (MVAs) are uncommon conditions frequently associated with aortic valve endocarditis. They may be complicated by perforation and severe mitral regurgitation (MR). Optimal treatment of MVA, and in particular the best timing for surgery, are uncertain. Case Report: A 62-year-old man with a recent history of dental surgery presented to the Emergency Department complaining relapsing fever. A first echocardiogram demonstrated infective endocarditis of the aortic valve. The patient was primarily managed with specific antibiotic therapy. Despite this, a few days later he suffered from splen-ic embolization and an MVA with MR was detected. Surgical replacement of the mitral and aortic valves was therefore performed. Conclusions: MVAs are infrequent but potentially severe complications of AV endocarditis. In the absence of definite treatment indication, the correct time for surgery should depend on concomitant clinical and infective features

    Low expression of Ki-67/MIB-1 labeling index in IDH wild type glioblastoma predicts prolonged survival independently by MGMT methylation status

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    PurposeThe Ki-67/MIB-1 labeling index (LI) is clinically used to differentiate between high and low-grade gliomas, while its prognostic value remains questionable. Glioblastoma (GBM) expressing wild-type isocitrate dehydrogenase IDHwt, a relatively common malignant brain tumor in adults, is characterized by a dismal prognosis. Herein, we have retrospectively investigated the prognostic role of Ki-67/MIB-1-LI in a large group of IDHwt GBM.MethodsOne hundred nineteen IDHwt GBM patients treated with surgery followed by Stupp's protocol in our Institution between January 2016 and December 2021 were selected. A cut-off value for Ki-67/MIB-1-LI was used with minimal p-value based approach.ResultsA multivariate analysis showed that Ki-67/MIB-1-LI expression < 15% significantly correlated with a longer overall survival (OS), independently from the age of the patients, Karnofsky performance status scale, extent of surgery and O-6-methylguanine (O6-MeG)-DNA methyltransferase promoter methylation status.ConclusionsAmong other studies focused on Ki-67/MIB-1-LI, this is the first observational study showing a positive correlation between OS of IDHwt GBM patients and Ki-67/MIB-1-LI that we propose as a new predictive marker in this subtype of GBM

    Role of Arterial Hypertension and Hypertension-Mediated Organ Damage in Cardiotoxicity of Anticancer Therapies

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    Purpose of the review: Arterial hypertension (AH) is the most common cardiovascular (CV) risk factor in the community and in oncologic patients. It also represents the most important CV condition predisposing to anticancer treatment-related cardiotoxicity. This risk is heightened in the presence of cardiac AH-mediated organ damage (HMOD). Influence of AH and HMOD on the development of cardiotoxicity will be reviewed, with a focus on specific scenarios and implications for management of oncologic patients. Recent findings: Not adequately controlled AH before or during anticancer treatments and/or development of AH during or after completion of such therapies have detrimental effects on the clinical course of oncologic patients, particularly if HMOD is present. As overlooking CV health can jeopardize the success of anticancer treatments, the goal for clinicians caring for the oncologic patient should include the treatment of AH and HMOD
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