4,203 research outputs found
Feature-based tuning of simulated annealing applied to the curriculum-based course timetabling problem
We consider the university course timetabling problem, which is one of the
most studied problems in educational timetabling. In particular, we focus our
attention on the formulation known as the curriculum-based course timetabling
problem, which has been tackled by many researchers and for which there are
many available benchmarks.
The contribution of this paper is twofold. First, we propose an effective and
robust single-stage simulated annealing method for solving the problem.
Secondly, we design and apply an extensive and statistically-principled
methodology for the parameter tuning procedure. The outcome of this analysis is
a methodology for modeling the relationship between search method parameters
and instance features that allows us to set the parameters for unseen instances
on the basis of a simple inspection of the instance itself. Using this
methodology, our algorithm, despite its apparent simplicity, has been able to
achieve high quality results on a set of popular benchmarks.
A final contribution of the paper is a novel set of real-world instances,
which could be used as a benchmark for future comparison
Fully Polarizable QM/Fluctuating Charge Approach to Two-Photon Absorption of Aqueous Solutions
We present the extension of the quantum/classical polarizable fluctuating
charge model to the calculation of single residues of quadratic response
functions, as required for the computational modeling of two-photon absorption
cross-sections. By virtue of a variational formulation of the quantum/classical
polarizable coupling, we are able to exploit an atomic orbital-based
quasienergy formalism to derive the additional coupling terms in the response
equations. Our formalism can be extended to the calculation of arbitrary order
response functions and their residues. The approach has been applied to the
challenging problem of one- and two-photon spectra of rhodamine 6G (R6G) in
aqueous solution. Solvent effects on one- and two-photon spectra of R6G in
aqueous solution have been analyzed by considering three different approaches,
from a continuum (QM/PCM) to two QM/MM models (non-polarizable QM/TIP3P and
polarizable QM/FQ). Both QM/TIP3P and QM/FQ simulated OPA and TPA spectra show
that the inclusion of discrete water solvent molecules is essential to increase
the agreement between theory and experiment. QM/FQ has been shown to give the
best agreement with experiments
Benign hepatocellular nodules of healthy liver: focal nodular hyperplasia and hepatocellular adenoma
Owing to the progress of imaging techniques, benign hepatocellular nodules are increasingly discovered in the clinical practice. This group of lesions mostly arises in the context of a putatively normal healthy liver and includes either pseudotumoral and tumoral nodules. Focal nodular hyperplasia and hepatocellular adenoma are prototypical examples of these two categories of nodules. In this review we aim to report the main pathological criteria of differential diagnosis between focal nodular hyperplasia and hepatocellular adenoma, which mainly rests upon morphological and phenotypical features. We also emphasize that for a correct diagnosis the clinical context such as sex, age, assumption of oral contraceptives, associated metabolic or vascular disturbances is of paramount importance. While focal nodular hyperplasia is a single entity epidemiologically more frequent than adenoma, the latter is representative of a more heterogeneous group which has been recently and extensively characterized from a clinical, morphological, phenotypical and molecular profile. The use of the liver biopsy in addition to imaging and the clinical context are important diagnostic tools of these lesions. In this review we will survey their systematic pathobiology and propose a diagnostic algorithm helpful to increase the diagnostic accuracy of not dedicated liver pathologists. The differential diagnosis between so-called typical and atypical adenoma and well differentiated hepatocellular carcinoma will also be discussed
Data of safety in a single-center alemtuzumab treated population
Alemtuzumab is approved for highly active MS and, in Europe, can be employed after other disease-modifying treatments (DMTs) as an escalation approach or first therapeutic option. The occurrence of secondary autoimmune adverse events and infections differs depending on the employed approach. In the manuscript entitled “Alemtuzumab treatment of multiple sclerosis in real-world clinical practice: report from a single Italian center” by di Ioia M. and collaborators, efficacy and safety data of alemtuzumab were evaluated in a real-world MS population. The aim of the article is to describe in detail the unexpected serious adverse events which occurred in this cohort during and after the administration of the alemtuzumab treatment. Adverse events were observed in 45,7% of the patients. These events were ranked as severe in 23% of the patients. We reported, in particular, cases of autoimmune hemolytic anemia (AIHA), pancytopenia, viral hepatitis E and noninfectious meningo-encephalomyelitis
Dual-energy CT in musculoskeletal imaging:technical considerations and clinical applications
Dual-energy CT stands out as a robust and innovative imaging modality, which has shown impressive advancements and increasing applications in musculoskeletal imaging. It allows to obtain detailed images with novel insights that were once the exclusive prerogative of magnetic resonance imaging. Attenuation data obtained by using different energy spectra enable to provide unique information about tissue characterization in addition to the well-established strengths of CT in the evaluation of bony structures. To understand clearly the potential of this imaging modality, radiologists must be aware of the technical complexity of this imaging tool, the different ways to acquire images and the several algorithms that can be applied in daily clinical practice and for research. Concerning musculoskeletal imaging, dual-energy CT has gained more and more space for evaluating crystal arthropathy, bone marrow edema, and soft tissue structures, including tendons and ligaments. This article aims to analyze and discuss the role of dual-energy CT in musculoskeletal imaging, exploring technical aspects, applications and clinical implications and possible perspectives of this technique.</p
Coadministration of Atorvastatin Prevents Nitroglycerin-Induced Endothelial Dysfunction and Nitrate Tolerance in Healthy Humans
ObjectivesWe aimed to assess whether concurrent administration of atorvastatin would modify the development of tolerance and endothelial dysfunction associated with sustained nitroglycerin (GTN) therapy in humans.BackgroundAnimal studies have demonstrated that administration of 3-hydroxy-3 methylglutaryl coenzyme A reductase inhibitors can protect against GTN-induced endothelial dysfunction and tolerance, likely through an antioxidant mechanism.MethodsThirty-six healthy male volunteers were randomized to receive continuous transdermal GTN (0.6 mg/h) and placebo, atorvastatin (80 mg/day) alone, or continuous transdermal GTN (0.6 mg/h) with concurrent atorvastatin (80 mg/day), all for 7 days. On the second visit, forearm blood flow was measured with venous-occlusion strain gauge plethysmography in response to incremental infusions of acetylcholine (7.5, 15, and 30 μg/min). Acetylcholine infusions were coinfused first with saline, and repeated during the coinfusion of vitamin C (24 mg/min). Blood pressure responses to sublingual GTN (400 μg) were assessed on both visits.ResultsAcetylcholine responses in the GTN plus placebo group were significantly attenuated versus those in the GTN plus atorvastatin and atorvastatin groups (p < 0.01). Coinfusion of vitamin C completely restored acetylcholine responses in the GTN plus placebo group (p < 0.01 vs. saline coinfusion), but caused no change in either the atorvastatin or the GTN plus atorvastatin groups. Blood pressure responses to sublingual GTN did not significantly change between visits in subjects receiving GTN plus atorvastatin and atorvastatin alone, but were significantly blunted in the GTN plus placebo group (p < 0.05).ConclusionsThe present findings demonstrate, for the first time in humans, that atorvastatin prevents both GTN-induced endothelial dysfunction and nitrate tolerance, likely by counteracting the GTN-induced increase in oxidative stress
A real-time RT-PCR assay for molecular identification and quantitation of feline morbillivirus RNA from biological specimens.
The aim of this study was to develop a real-time RT-PCR to detect and quantitate feline
morbillivirus (FeMV) RNA in biological samples. Primers and probe were targeted on a conserved
region of FeMV P/V/C gene. To validate the assay with field samples, a total number of specimens
of cats have been recruited including 264 urine and blood samples and compared with a generic
RT-PCR targeting the L protein encoding gene of morbilliviruses. In addition, 385 tissue samples
from 35 carcasses of cats have been also employed. RNA titres were low in all tested samples.
Results also indicated the absence of cross-reaction with related morbilliviruses and existing
pathogens of cats. However, in tissues with low levels of FeMV RNA, the presence of viral antigen
was confirmed by immunohistochemistry targeting the N viral protein. This newly described assay
allows for a rapid, accurate and reliable quantitative detection of FeMV RNA that can be applied
for diagnostics and research studies
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