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In this work we extend some ideas about greedy algorithms, which are well-established tools for, e.g., kernel bases, and exponential-polynomial splines whose main drawback consists in possible overfitting and consequent oscillations of the approximant. To partially overcome this issue, we develop some results on theoretically optimal interpolation points. Moreover, we introduce two algorithms which perform an adaptive selection of the spline interpolation points based on the minimization either of the sample residuals (f-greedy), or of an upper bound for the approximation error based on the spline Lebesgue function (λ -greedy). Both methods allow us to obtain an adaptive selection of the sampling points, i.e., the spline nodes. While the f-greedy selection is tailored to one specific target function, the λ -greedy algorithm enables us to define target-data-independent interpolation nodes. [ABSTRACT FROM AUTHOR]

An elliptic partial differential equation with a singular forcing term, describing a steady state flow determined by a pulse-like extraction at a constant volumetric rate, is approximated by a radial basis function approach which takes advantage of decomposing the original domain. The discretization error of such scheme is numerically estimated and we also face up to instability issues. This produces an effective tool for real applications, as confirmed by comparisons with classical grid-based approaches. [ABSTRACT FROM AUTHOR]

The aims of the present work were to evaluate the impact of ultraviolet treatment of remilled semolina on structural development of dough during mixing and leavening and to define a mathematical modelling for leavened doughs. The re-milled semolina was treated with UVC irradiation for 5,15, 30 and 120 min. The UVC treatment caused some changes of moisture content, colour and dough farinographic indices. The leavening kinetic was investigated by recording over time the variation of the dough volume by means of Image Analysis procedure. The mathematical procedure in this study was to model the evolution of a macroscopic morphology descriptor (volume) by a data-driven approach; the Particle Filter (PF) methodology incorporates the direct observations of the evolutionary dynamics in order to predict the data evolution. A specific differential problem is calibrated on the volume data of semolina doughs. An interesting feature of the proposed scheme is its ability to forecast variable states even when little information is available. More in detail, the volume variations are represented with a stochastic differential model and the dynamics of dough leavening are described by an evolution-observation scheme. The approach suggests the possibility of overcoming the costly data managing and image acquisitions. [ABSTRACT FROM AUTHOR]

Background: Osteosarcoma (OS) is a primary bone malignancy that mostly affects young people, characterized by high metastatic potential, and a marked chemoresistance that is responsible for disease relapse in most patients. Therefore, it is necessary to identify novel molecules to setup targeted strategies to improve the clinical outcome. The enzyme nicotinamide N‐methyltransferase (NNMT) catalyses the N‐methylation of nicotinamide and other analogs, playing a crucial role in the biotransformation of drugs and xenobiotics. NNMT overexpression was reported in a wide variety of cancers, and several studies demonstrated that is able to promote cell proliferation, migration and resistance to chemotherapy. The aim of this study was to explore the potential involvement of NNMT in OS. Methods: Immunohistochemical analyses have been performed to evaluate NNMT expression in selected OS and healthy bone tissue samples. Subsequently, OS cell lines have been transfected with vectors targeting NNMT mRNA (shRNAs) and the impact of this downregulation on migration, cell proliferation, and response to chemotherapeutic treatment was also analysed by wound healing, MTT, SRB and Trypan blue assays, respectively. Results: Results showed that OS samples display a significantly higher NNMT expression compared with healthy tissue. Preliminary results suggest that NNMT silencing in OS cell lines is associated to a decrease of cell proliferation and migration, as well as to enhanced sensitivity to chemotherapy. Data obtained showed that NNMT may represent an interesting marker for OS detection and a promising target for effective anti‐cancer therapy. [ABSTRACT FROM AUTHOR]

Objective: To assess the long-term outcome of computed tomography-guided radiofrequency ablation (CT-guided RFA) in patients with suspected osteoid osteoma (OO).Materials and Methods: Single-center retrospective study. Patients with clinical suspicion and imaging diagnosis of osteoid osteoma were treated by CT-guided RFA using the same device with either a 7- or 10-mm active tip electrode. Specific precautions were applied in case of articular or spinal OO. Patients were contacted by phone to evaluate the long-term outcome in terms of pain, ability to perform daily activities (including sports), and long-term complications. Success was defined as the absence of residual pain and ability to perform daily activities normally.Results: From 2008 to 2015, 126 patients were treated by CT-guided RFA for OO in our institution. Mean patient age was 26.1 years (SD = 11, range 1-53); mean delay to diagnosis was 16.9 months (SD = 15.2, range 1-120). Among patients who answered the follow-up call (n = 88), the overall success rate was 94.3%: 79/88 (89.8%) had primary success of the procedure, and 4/88 (4.5%) had a secondary success (repeat-RFA after pain recurrence). Mean follow-up time was 34.6 months (SD = 24.7, range 3-90). Few complications occurred: two mild reversible peripheral nerve injuries, one brachial plexus neuropathy, one broken electrode tip fragment, and one muscular hematoma.Conclusion: Osteoid osteoma can be effectively and safely treated by CT-guided RFA using the presented ablation protocol. Beneficial effects of the treatment persist at long-term follow-up. [ABSTRACT FROM AUTHOR]

The scientific and application-oriented interest in the Laplace transform and its inversion is testified by more than 1000 publications in the last century. Most of the inversion algorithms available in the literature assume that the Laplace transform function is available everywhere. Unfortunately, such an assumption is not fulfilled in the applications of the Laplace transform. Very often, one only has a finite set of data and one wants to recover an estimate of the inverse Laplace function from that. We propose a fitting model of data. More precisely, given a finite set of measurements on the real axis, arising from an unknown Laplace transform function, we construct a dth degree generalized polynomial smoothing spline, where d = 2m-1, such that internally to the data interval it is a dth degree polynomial complete smoothing spline minimizing a regularization functional, and outside the data interval, it mimics the Laplace transform asymptotic behavior, i.e. it is a rational or an exponential function (the end behavior model), and at the boundaries of the data set it joins with regularity up to order m-1, with the end behavior model.We analyze in detail the generalized polynomial smoothing spline of degree d = 3. This choice was motivated by the (ill)conditioning of the numerical computation which strongly depends on the degree of the complete spline. We prove existence and uniqueness of this spline. We derive the approximation error and give a priori and computable bounds of it on the whole real axis. In such a way, the generalized polynomial smoothing spline may be used in any real inversion algorithm to compute an approximation of the inverse Laplace function. Experimental results concerning Laplace transform approximation, numerical inversion of the generalized polynomial smoothing spline and comparisons with the exponential smoothing spline conclude the work. [ABSTRACT FROM AUTHOR]

Abstract: We address design of a numerical algorithm for solving the linear system arising in numerical inversion of Laplace transforms in real case [L. D’Amore, A. Murli, Regularization of a Fourier series method for the Laplace transform inversion with real data, Inverse Problems 18 (2002) 1185–1205]. The matrix has a condition number that grows almost exponentially and the singular values decay gradually towards zero. In such a case, because of this intrinsic strong instability, the main difficulty of any numerical computation is the ability of discovering at run time, only using data, what is the maximum attainable accuracy on the solution. In this paper, we use GMRES with the aim of relating the current residuals to the maximum attainable accuracy of the approximate solution by using a suitable stopping rule. We prove that GMRES stops after, at most, as many iterations as the number of the largest eigenvalues (compared to the machine epsilon). We use a split preconditioner that symmetrically precondition the initial system. By this way, the largest eigenvalue dynamically provides the estimate of the condition number of the matrix. [Copyright &y& Elsevier]

Radiographs (XR), computed tomography (CT) or magnetic resonance imaging (MRI) are regularly analyzed to determine whether a bone lesion is benign or malignant. An online quiz was created providing 15 cases with a clinical summary, MRI, CT, and XR. After each image, participants were asked to rate the probability (0–100%) the bone tumor was malignant. Order and difficulty of the images were randomly determined. Probability statements regarding the diagnosis were actualized along the sequence of exam, to quantify how the degree of belief changed to account for evidence from those exams. 64 physicians participated and provided 154 assessments from 1 (n = 18) to 3 (n = 44) different cases. After the first image, participants favored the correct malignancy status at 70%; 80% after the second and 80% after the third one. Participants were more likely to favor the correct malignancy status when the lesion was malignant and when first confronted with XR or CT, rather than MRI, though the most predictive factor of correct diagnosis was the difficulty of the case. In conclusion, the additional information provided by successive imaging studies was moderate. XR or CT seemed more appropriate than MRI as first imaging study. Bypassing XR should be discouraged. [ABSTRACT FROM AUTHOR]

The minimisation of the total cost of ownership is hard to be faced by the owners of large scale computing systems, without affecting negatively the quality of service for the users. Modern datacenters, often included in distributed environments, appear to be 'elastic', i.e., they are able to shrink or enlarge the number of local physical or virtual resources, also by recruiting them from private/public clouds. This increases the degree of dynamicity, making the infrastructure management more and more complex. Here, we report some advances in the realisation of an adaptive scheduling controller (ASC) which, by interacting with the datacenter resource manager, allows an effective and an efficient usage of resources. In particular, we focus on the mathematical formalisation of the ASC's kernel that allows to dynamically configure, in a suitable way, the datacenter resources manager. The described formalisation is based on a probabilistic approach that, starting from both a hystorical resources usage and on the actual users request of the datacenter resources, identifies a suitable probability distribution for queue time with the aim to perform a short term forecasting. The case study is the SCoPE datacenter at the University of Naples Federico II. [ABSTRACT FROM AUTHOR]

Calcinosis is a typical feature of systemic sclerosis (SSc) and can be found in many different tissues including the superficial soft tissues, periarticular structures, muscles, and tendons. It can also provoke erosive changes on bones. Investigation is conducted most often with plain radiographs. However, when a more detailed assessment is necessary, multidetector computed tomography (MDCT) is helpful owing to its multiplanar reformat (MPR) ability. The purpose of this review is to provide an overview of the various appearances of calcinosis in SSc patients as visualized at MDCT. [Copyright &y& Elsevier]

Objective: To report the biopsy findings of osteoid osteoma (OO) and OO-mimicking lesions, assess their distinctive multidetector computed tomography (MDCT) features and evaluate treatment by radiofrequency ablation (RFA).Methods: In this multicentric retrospective study, 80 patients (54 male, 26 female, mean age 24.1 years, range 5-48) with presumed (clinical and MDCT features) OO were treated by percutaneous RFA between May 2002 and June 2009. Per-procedural biopsies were always performed. The following MDCT features were assessed: skeletal distribution and location within the bone, size, central calcification, surrounding osteosclerosis and periosteal reaction. Clinical success of RFA was evaluated.Results: Histopathological diagnoses were: 54 inconclusive biopsies, 16 OO, 10 OO-mimicking lesions (5 chronic osteomyelitis, 3 chondroblastoma, 1 eosinophilic granuloma, 1 fibrous dysplasia). OO-mimicking lesions were significantly greater in size (p = 0.001) and presented non-significant trends towards medullary location (p = 0.246), moderate surrounding osteosclerosis (p = 0.189) and less periosteal reaction (p = 0.197), compared with OO. Primary success for ablation of OO-mimicking lesions was 100% at 1 month, 85.7% at 6 and 12 months, and 66.7% at 24 months. Secondary success was 100%.Conclusion: Larger size, medullary location, less surrounding osteosclerosis and periosteal reaction on MDCT may help differentiate OO-mimicking lesions from OO. OO-mimicking lesions are safely and successfully treated by RFA. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the accuracy of computed tomography angiography (CTA) in predicting arterial encasement by limb tumours, by comparing CTA with surgical findings (gold standard).Methods: Preoperative CTA images of 55 arteries in 48 patients were assessed for arterial status: cross-sectional CTA images were scored as showing a fat plane between artery and tumour (score 0), slight contact between artery and tumour (score 1), partial arterial encasement (score 2) or total arterial encasement (score 3). Reformatted CTA images were assessed for arterial displacement, rigid wall, stenosis or occlusion. At surgery, arteries were classified as free or surgically encased; 45 arteries were free and 10 were surgically encased.Results: Multivariate logistic regression identified the axial CTA score as a relevant predictor for arterial encasement and subsequent vascular intervention during surgery. All sites where CTA showed a fat plane between the tumour and the artery were classified as free at surgery (n = 28/28). The sensitivity of total arterial encasement on CTA (score 3) was 90%, specificity 93%, accuracy 93% and positive likelihood ratio 13.5.Conclusion: CTA evidence of total arterial encasement is a highly specific indication of arterial encasement. The presence of fat between the tumour and the artery on CTA rules out arterial involvement at surgery. [ABSTRACT FROM AUTHOR]