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Rome, Italy

The University of Rome II also known as University of Rome Tor Vergata is a public research university located in Rome, Italy. Its current president is Giuseppe Novelli, a professor in the Faculty of Medicine and Surgery.It was established in 1981 with the goal of providing high quality education for students preparing to meet the ever-evolving needs and opportunities of the 21st century workforce. Despite its young age, Tor Vergata has already reached high quality standards in Italy and Europe. Located in the South-Eastern suburb of Rome, the university combines a liberal arts tradition with emphasis on career orientation in the field of Economics, Engineering, science and Medicine.Many Professors of the University are important members of the italian cultural and political environment. Wikipedia.

Tinnirello I.,University of Palermo | Bianchi G.,University of Rome Tor Vergata | Xiao Y.,University of Alabama
IEEE Transactions on Vehicular Technology | Year: 2010

With the popularity of the IEEE 802.11 standards, many analytical saturation throughput studies for the distributed coordination function (DCF) have been reported. In this paper, we outline a number of issues and criticalities raised by previously proposed models. In particular, a careful look at backoff counter decrement rules allows us to conclude that, under saturation conditions, the slot immediately following a successful transmission can be accessed only by the station (STA) that has successfully transmitted in the previous channel access. Moreover, due to the specific acknowledgment (ACK) timeout setting adopted in the standard, the slot immediately following a collision cannot be accessed by any STA. Thus, the hypothesis of uncorrelation between consecutive channel slots and statistical homogeneity is not generally true. We propose a new backoff decrement model that retains the simplicity of traditional DCF models while being able to take into account such a correlation, and we compare the accuracy of our model with that of previously proposed approaches. © 2006 IEEE. Source

Rizzo R.,University of Catania | Gulisano M.,University of Catania | Cali P.V.,University of Catania | Curatolo P.,University of Rome Tor Vergata
European Journal of Paediatric Neurology | Year: 2013

Marrocco G.,University of Rome Tor Vergata
IEEE Wireless Communications | Year: 2010

Things equipped with electronic labels having both identification and sensing capability could naturally be turned into digital entities in the framework of the Internet of Things. Radio frequency identification (RFID) technology offers the natural background to achieve such functionalities, provided that the basic physics governing the sensing and electromagnetic interaction phenomena are fully exploited. The sensing of Things is here reviewed from an electromagnetic perspective with the purpose of showing how advanced performance may be achieved by means of low-cost batteryless devices. A possible classification of basic sensing modalities is introduced, and many ideas, at different stages of maturity, are then discussed with the help of examples ranging from the sensing of non-living Things up to the more challenging sensing of Humans. © 2010 IEEE. Source

Arca-Sedda M.,University of Rome La Sapienza | Arca-Sedda M.,University of Rome Tor Vergata | Capuzzo-Dolcetta R.,University of Rome La Sapienza
Monthly Notices of the Royal Astronomical Society | Year: 2014

Nuclear star clusters (NSCs) are often present in spiral galaxies as well as resolved stellar nuclei (SNi) in elliptical galaxies centres. Ever growing observational data indicate the existence of correlations between the properties of these very dense central star aggregates and those of host galaxies, which constitute a significant constraint for the validity of theoretical models of their origin and formation. In the framework of the well-known 'migratory and merger' model for NSC and SN formation, in this paper we obtain, first, by a simple argument the expected scaling of the NSC/SN mass with both time and parent galaxy velocity dispersion in the case of dynamical friction as dominant effect on the globular cluster system evolution. This generalizes previous results by Tremaine et al. and is in good agreement with available observational data showing a shallow correlation between NSC/SN mass and galactic bulge velocity dispersion. Moreover, we give statistical relevance to predictions of this formation model, obtaining a set of parameters to correlate with the galactic host parameters.We find that the correlations between the masses of NSCs in the migratory model and the global properties of the hosts reproduce quite well the observed correlations, supporting the validity of the migratory-merger model. In particular, one important result is the flattening or even decrease of the value of the NSC/SN mass obtained by the merger model as function of the galaxy mass for high values of the galactic mass, i.e. ≳3 × 1011 M, in agreement with some growing observational evidence. © 2014 The Authors. Source

De Grijs R.,Peking University | Bono G.,University of Rome Tor Vergata | Bono G.,National institute for astrophysics
Astronomical Journal | Year: 2014

The accuracy of extragalactic distance measurements ultimately depends on robust, high-precision determinations of the distances to the galaxies in the local volume. Following our detailed study addressing possible publication bias in the published distance determinations to the Large Magellanic Cloud (LMC), here we extend our distance range of interest to include published distance moduli to M31 and M33, as well as to a number of their wellknown dwarf galaxy companions. We aim at reaching consensus on the best, most homogeneous, and internally most consistent set of Local Group distance moduli to adopt for future, more general use based on the largest set of distance determinations to individual Local Group galaxies available to date. Based on a careful, statistically weighted combination of the main stellar population tracers (Cepheids, RR Lyrae variables, and the magnitude of the tip of the red-giant branch), we derive a recommended distance modulus to M31 of (m - M) M31 0 = 24.46 ± 0.10 mag - adopting as our calibration an LMC distance modulus of (m - M)LMC 0 = 18.50 mag - and a fully internally consistent set of benchmark distances to key galaxies in the local volume, enabling us to establish a robust and unbiased, near-field extragalactic distance ladder. © 2014. The American Astronomical Society. All rights reserved. Source

Pigolotti S.,Polytechnic University of Catalonia | Benzi R.,University of Rome Tor Vergata
Physical Review Letters | Year: 2014

We study a stochastic spatial model of biological competition in which two species have the same birth and death rates, but different diffusion constants. In the absence of this difference, the model can be considered as an off-lattice version of the voter model and presents similar coarsening properties. We show that even a relative difference in diffusivity on the order of a few percent may lead to a strong bias in the coarsening process favoring the more agile species. We theoretically quantify this selective advantage and present analytical formulas for the average growth of the fastest species and its fixation probability. © 2014 American Physical Society. Source

Van De Weert M.,Copenhagen University | Stella L.,University of Rome Tor Vergata
Journal of Molecular Structure | Year: 2011

In recent years fluorescence quenching has become a popular tool to investigate various aspects of ligand binding. Unfortunately, various pitfalls are often overlooked in a large number of papers, published in many different journals. In this criticism we discuss a number of possible mistakes and show how they may affect the data and their analysis. Moreover, we point to problems in the understanding of the fundamentals of fluorescence quenching, and show direct contradictions within many of these papers. This review hopefully contributes to a re-appraisal of the published literature and to a more appropriate use of fluorescence quenching to study ligand binding. © 2011 Elsevier B.V. All rights reserved. Source

Stella L.,University of Rome Tor Vergata
Journal of Chemical Education | Year: 2011

The influence of the excited-state lifetime of a fluorophore on its susceptibility to collisional quenching is discussed. In the case of cytochrome c, FRET to the heme moiety strongly reduces the tryptophan fluorescence lifetime. This should be taken into account to correctly evaluate the tryptophan solvent accessibility from acrylamide quenching experiments. Copyright © 2011 American Chemical Society and Division of Chemical Education, Inc. Source

Zhang J.,Sophia University | Shen T.,Sophia University | Marino R.,University of Rome Tor Vergata
Control Engineering Practice | Year: 2010

This paper presents a model-based control scheme to the cold-start speed control in spark ignition (SI) engines. The multi-variable control algorithm is developed with the purpose of improving the transient performance of the starting engine speed: the control inputs are the fuel injection, the throttle and the spark advance (SA), while the engine speed and the air mass flow rate are the measured signals. The fuel injection is performed with a dual sampling rate system: the cycle-based fuel injection command is individually adjusted for each cylinder by using a TDC (top dead center)-based air charge estimation. The desired performance for speed regulation is achieved by using a coordinated control of SA and throttle operation. The speed error convergence of the closed loop system is proved for simplified, second-order model with a time-delay, and the robustness with respect to parameter uncertainties is investigated. The performance and the robustness with respect to modeling uncertainties of the proposed control scheme are tested using an industrial engine simulator with six cylinders. © 2010 Elsevier Ltd. Source

Borra S.,University of Rome Tor Vergata | Di Ciaccio A.,University of Rome La Sapienza
Computational Statistics and Data Analysis | Year: 2010

The estimators most widely used to evaluate the prediction error of a non-linear regression model are examined. An extensive simulation approach allowed the comparison of the performance of these estimators for different non-parametric methods, and with varying signal-to-noise ratio and sample size. Estimators based on resampling methods such as Leave-one-out, parametric and non-parametric Bootstrap, as well as repeated Cross Validation methods and Hold-out, were considered. The methods used are Regression Trees, Projection Pursuit Regression and Neural Networks. The repeated-corrected 10-fold Cross-Validation estimator and the Parametric Bootstrap estimator obtained the best performance in the simulations. © 2010 Elsevier B.V. All rights reserved. Source

Abramo G.,CNR Institute for System Analysis and Computer Science Antonio Ruberti | D'Angelo C.A.,University of Rome Tor Vergata
Journal of Informetrics | Year: 2014

National policies aimed at fostering the effectiveness of scientific systems should be based on reliable strategic analysis identifying strengths and weaknesses at field level. Approaches and indicators thus far proposed in the literature have not been completely satisfactory, since they fail to distinguish the effect of the size of production factors from that of their quality, particularly the quality of labor. The current work proposes an innovative "input-oriented" approach, which permits: (i) estimation of national research performance in a field and comparison to that of other nations, independent of the size of their respective research staffs; and, for fields of comparable intensity of publication, (ii) identification of the strong and weak research fields within a national research system on the basis of international comparison. In reference to the second objective, the proposed approach is applied to the Italian case, through the analysis of the 2006-2010 scientific production of the Italian academic system, in the 200 research fields where bibliometric analysis is meaningful. © 2014 Elsevier Ltd. Source

Bianchi G.,University of Rome Tor Vergata
IEEE Communications Letters | Year: 2011

SEBA is a recently proposed probabilistic identification-free batch authentication solution for RFID tags. It significantly differs from traditional RFID authentication approaches: rather than relying on authentication information delivered by the tags, it exploits the position of the tags' transmissions in response to an authentication challenge. This letter revisits, and meanwhile extends, SEBA. We show that SEBA is a particular case of a more general framework, called SEBA+, which envisions multiple tag responses in a frame. These are in turns interpreted as a Bloom filter, whose authenticity is verified against an authenticator Bloom filter comprising all the deployed tags' computed responses. Our proposed extension significantly improves SEBA's performance when more stringent counterfeit RFID tag detection capabilities are required. © 2011 IEEE. Source

Baciocchi R.,University of Rome Tor Vergata
Water, Air, and Soil Pollution | Year: 2013

This paper provides a short overview of the main oxidation processes more commonly applied for the remediation of contaminated sites, with specific reference to their application for the in situ remediation of contaminated sites, i.e. In Situ Chemical Oxidation (ISCO). A review of the main patents issued on this topic shows the relevant contribution to the development of this technology in the last 20 years, especially in the USA. The still limited deployment of ISCO in other geographical areas may be improved by the increased acceptance of the technology that may come from the development of proper application guidelines based on accepted design criteria. The latter ones are also discussed in this paper with reference to the application of Fenton's treatment. © Springer Science+Business Media Dordrecht 2013. Source

Porretta A.,University of Rome Tor Vergata
Dynamic Games and Applications | Year: 2014

We consider the planning problem for a class of mean field games, consisting in a coupled system of a Hamilton-Jacobi-Bellman equation for the value function u and a Fokker-Planck equation for the density m of the players, whereas one wishes to drive the density of players from the given initial configuration to a target one at time T through the optimal decisions of the agents. Assuming that the coupling F(x,m) in the cost criterion is monotone with respect to m, and that the Hamiltonian has some growth bounded below and above by quadratic functions, we prove the existence of a weak solution to the system with prescribed initial and terminal conditions m 0, m 1 (positive and smooth) for the density m. This is also a special case of an exact controllability result for the Fokker-Planck equation through some optimal transport field. © 2013 Springer Science+Business Media New York. Source

Tauraso R.,University of Rome Tor Vergata
Electronic Journal of Combinatorics | Year: 2010

We show that for any prime prime p ≠ 2, by expressing the left-hand side as a combination of alternating multiple harmonic sums. Source

Verrelli C.M.,University of Rome Tor Vergata
International Journal of Control | Year: 2011

On the basis of the ideas recently presented in Tomei and Verrelli (Tomei, P., and Verrelli, C.M. (2010), 'Learning Control for Induction Motor Servo Drives with Uncertain Rotor Resistance', International Journal of Control, 83, 1515-1528) and Marino et al. (Marino, R., Tomei, P., and Verrelli, C.M. (2011), 'Robust Adaptive Learning Control for Nonlinear Systems with Extended Matching Unstructured Uncertainties', International Journal of Robust and Nonlinear Control, Early View, doi: 10.1002/rnc.1720), we briefly show how the adaptive learning control design proposed in Liuzzo and Tomei (Liuzzo, S., and Tomei, P. (2009), Global Adaptive Learning Control of Robotic Manipulators by Output Error Feedback, International Journal of Adaptive Control and Signal Processing, 23, 97-109) can be extended to robotic manipulators driven by nonsalient-pole (surface) permanent magnet synchronous motors. Unstructured uncertain dynamics (that is no parameterisation is available for the uncertainties) of the rigid robot with rotational joints are considered as well as uncertainties in stator resistances of the synchronous motors are taken into account. Two solutions with clear stability proofs are presented: a global decentralised control via state feedback and a semi-global control via output feedback. Output tracking of known periodic reference signals and learning of corresponding uncertain input reference signals are achieved. Available results in the literature are thus improved since no simplification concerning negligible electrical motor dynamics is used. © 2011 Taylor & Francis. Source

Benzi R.,University of Rome Tor Vergata | Pinton J.-F.,French National Center for Scientific Research
Physical Review Letters | Year: 2010

We study a simple magnetohydrodynamical approach in which hydrodynamics and MHD turbulence are coupled in a shell model, with given dynamo constraints in the large scales. We consider the case of a low Prandtl number fluid for which the inertial range of the velocity field is much wider than that of the magnetic field. Random reversals of the magnetic field are observed and it shown that the magnetic field has a nontrivial evolution-linked to the nature of the hydrodynamics turbulence. © 2010 The American Physical Society. Source

Breccia M.,University of Rome La Sapienza | Lo-Coco F.,University of Rome Tor Vergata
Expert Opinion on Pharmacotherapy | Year: 2012

Introduction: Acute promyelocytic leukemia (APL), the most rapidly fatal leukemia only two decades ago, has been converted into the most frequently curable leukemia by the advent of all-trans retinoic acid (ATRA) and its combination with anthracycline-based chemotherapy. More recently, arsenic trioxide (ATO) has been shown to be the most effective single agent in this disease and has been approved for the treatment of relapsed patients both in the United States and Europe. Moreover, ATO has been included in the design of several front-line studies, with the aim to reduce therapy-related toxicity while maintaining the potential of cure. Areas covered: First, this review briefly discusses the mechanisms of action and the toxicity profile of ATO. Furthermore, the reported experience on the use of ATO as single agent or in combinatorial schemes both in relapsed and in newly diagnosed patients with APL is critically reviewed. Finally, the use of this agent in special subsets of patients unfit to receive conventional chemotherapy is discussed, along with its potential role in maintenance therapy. Expert opinion: While the role of ATO as single agent or in combination with ATRA is well established and recommended by the European LeukemiaNet guidelines as a first option for relapsed patients, the role of the drug in newly diagnosed patients is still uncertain and based only on evidence levels mostly originating from non-randomized trials. The results of ongoing randomized studies should better define the role of ATO in front-line therapy. © 2012 Informa UK, Ltd. Source

Amelio I.,University of Leicester | Cutruzzola F.,University of Rome La Sapienza | Antonov A.,University of Leicester | Agostini M.,University of Leicester | And 2 more authors.
Trends in Biochemical Sciences | Year: 2014

Serine and glycine are biosynthetically linked, and together provide the essential precursors for the synthesis of proteins, nucleic acids, and lipids that are crucial to cancer cell growth. Moreover, serine/glycine biosynthesis also affects cellular antioxidative capacity, thus supporting tumour homeostasis. A crucial contribution of serine/glycine to cellular metabolism is through the glycine cleavage system, which refuels one-carbon metabolism; a complex cyclic metabolic network based on chemical reactions of folate compounds. The importance of serine/glycine metabolism is further highlighted by genetic and functional evidence indicating that hyperactivation of the serine/glycine biosynthetic pathway drives oncogenesis. Recent developments in our understanding of these pathways provide novel translational opportunities for drug development, dietary intervention, and biomarker identification of human cancers. © 2014. Source

Ferrazzoli D.,University of Rome Tor Vergata
CNS & neurological disorders drug targets | Year: 2013

While many studies have investigated electroencephalographic (EEG) features of dementia, few have analysed the relationship between EEG and cerebrospinal fluid biomarkers in cognitive impairment. Seizures are frequently observed at the end stage of Alzheimer disease, and experimental animal studies support the view that epileptiform activity may contribute to the cognitive decline. In this paper, after reviewing literature findings concerning the role of EEG in dementia, we show the preliminary results of our study aimed to correlate the presence of epileptiform EEG patterns with cerebrospinal fluid biomarkers in order to better define the prognosis of dementia. Our study shows a clear relationship between phospho-tau protein levels and epileptiform EEG pattern. This finding seems to suggest in humans the observation made in animal models that not only β-amyloid protein, but also tau and phospho-tau proteins, are involved in the aberrant regulation of neural transmission possibly contributing to EEG deterioration, cognitive decline and worse prognosis. On the basis of the relationship between phospho-tau protein, cognitive decline and epileptogenicity we suspect that high liquoral phospho-tau levels and epileptiform EEG pattern may provide an early identification of patients with dementia and/or represent an aggressive phenotype of dementia. We propose that qualitative EEG analysis integrated with cerebrospinal biomarkers may be extensively used to better define dementia. Source

Aloisio R.,National Institute of Nuclear Physics, Italy | Boncioli D.,University of Rome Tor Vergata
Astroparticle Physics | Year: 2011

The recent results of the Pierre Auger Observatory on the possible correlation of Ultra High Energy Cosmic Rays events and several nearby discrete sources could be the starting point of a new era with charged particles astronomy. In this paper we introduce a simple model to determine the effects of any local distribution of sources on the expected flux. We consider two populations of sources: faraway sources uniformly distributed and local point sources. We study the effects on the expected flux of the local distribution of sources, referring also to the set of astrophysical objects whose correlation with the Auger events is experimentally claimed. © 2011 Elsevier B.V. All rights reserved. Source

Marcelli L.,University of Rome Tor Vergata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2011

Piras F.,Neuropsychiatry Laboratory | Chiapponi C.,Neuropsychiatry Laboratory | Girardi P.,University of Rome La Sapienza | Caltagirone C.,Neuropsychiatry Laboratory | And 2 more authors.
Cortex | Year: 2015

The most widely accepted model of obsessive-compulsive disorder (OCD) assumes brain abnormalities in the "affective circuit", mainly consisting of volume reduction in the medial orbitofrontal, anterior cingulate and temporolimbic cortices, and tissue expansion in the striatum and thalamus. The advent of whole-brain, voxel-based morphometry (VBM) has provided increasing evidence that regions outside the "affective" orbitofronto-striatal circuit are involved in OCD. Nevertheless, potential confounds from the different image analysis methods, as well as other factors, such as patients' medication and comorbidity status, may limit generalization of results.In the present paper, we systematically reviewed the whole-brain VBM literature on OCD by focussing specifically on degree of consistency between studies, extent to which findings have been replicated and interrelation between clinical variables and OCD anatomy, a potentially crucial factor that has been systematically examined only in a limited number of studies. The PubMed database was searched through February 2012. A total of 156 studies were identified; 18 of them fulfilled the inclusion/exclusion criteria and included 511 patients and 504 controls. Results support the notion that the brain alterations responsible for OCD are represented at the network level, and that widespread structural abnormalities may contribute to neurobiological vulnerability to OCD. Apart from defects in regions within the classic "affective" circuit, volume reduction of the cortical source of the dorsolateral (DL) prefronto-striatal "executive" circuit (dorsomedial, DL, ventrolateral and frontopolar prefrontal cortices), and of reciprocally connected regions (temporo-parieto-occipital associative areas) is consistently described in OCD patients. Moreover, increased volume of the internal capsule and reduced frontal and parietal white matter volumes may account for altered anatomical connectivity in fronto-subcortical circuitry. Morphometric changes in both "affective" and "executive" parallel the disease clinical course, being at the same time responsible for variation in symptom severity. Thus, OCD mechanisms involve a more widespread network of cerebral dysfunctions than previously thought, which may explain the heterogeneity in clinical manifestations and symptom severity. © 2013 Elsevier Ltd. Source

Stellato A.,University of Rome Tor Vergata
Journal of Integrative Agriculture | Year: 2012

The Semantic Web seems finally close to maintaining its promise about a real world-wide graph of interconnected resources. The SPARQL query language and protocols and the Linked Open Data initiative have laid the way for endless data endpoints sparse around the globe. However, for the Semantic Web to really happen, it does not suffice to get billions of triples out there: these must be shareable, interlinked and conform to widely accepted vocabularies. While more and more data are converted from already available large knowledge repositories of companies and organizations, the question whether these should be carefully converted to semantically consistent ontology vocabularies or find other shallow representations for their content naturally arises. The danger is to come up with massive amounts of useless data, a boomerang which could result to be contradictory for the success of the web of data. In this paper, I provide some insights on common problems which may arise when porting huge amount of existing data or conceptual schemes (very common in the agriculture domain) to resource description framwork (RDF), and will address different modeling choices, by discussing in particular the relationship between the two main modeling vocabularies offered by W3C: OWL and SKOS. © 2012 Chinese Academy of Agricultural Sciences. Source

Naganuma T.,Japan International Center for Materials Nanoarchitectonics | Traversa E.,Japan International Center for Materials Nanoarchitectonics | Traversa E.,University of Rome Tor Vergata
Nanoscale | Year: 2012

A high concentration of Ce 3+ ions, above 80%, was created in 5 nm thick cerium oxide nanoparticle (nanoceria) layers deposited on a polymer substrate. The reduction from Ce 4+ to Ce 3+ was achieved by irradiating the nanoceria layers with Ar ions, which resulted in the formation of oxygen vacancies at the surface. The samples were exposed to ambient air and compared with nanoceria pellets. Ce retained the 3+ valence state in the particle layers, but not in the pellets, even after 47 days of exposure to humid air. Thus, the irradiated nanoceria particle layers contain a high level of Ce 3+ ions and possess an outstanding stability in air. © 2012 The Royal Society of Chemistry. Source

Rosso F.,University of Turin | Bisicchia S.,University of Rome Tor Vergata | Bonasia D.E.,AO CTO M | Amendola A.,University of Iowa
American Journal of Sports Medicine | Year: 2015

Background: Meniscal allograft transplantation (MAT) was developed as a means of treating the symptoms of compartmental overload after meniscectomy. Despite more than 20 years of research in this field, many controversies still exist regarding meniscal transplantation. Purpose: The aims of this study were to assess (1) the quality of the published studies on MAT; (2) the indications for this type of surgery; (3) the methods used for preservation, sizing, and fixation of the allograft; and (4) the clinical and radiographic outcomes of this procedure and its role in preventing osteoarthritis. Study Design: Systematic review. Methods: Inclusion criteria for the articles were (1) English language, (2) peer-reviewed clinical studies with evidence levels 1 to 4, (3) reported clinical and/or radiological outcomes of MAT isolated or combined with other procedures, (4) minimum 12-month follow-up, (5) case series of at least 10 patients, and (6) a follow-up rate of at least 80% (no more than 20% of patients lost to follow-up). Results: A total of 55 studies matched the inclusion criteria (2 level 2, 7 level 3, and 46 level 4). The average Coleman methodology score was 49.73 ± 12.41 (range, 24-81). There was agreement in the literature regarding the indications for MAT: joint line pain and tenderness correlated with previous meniscectomy, young patients, without diffuse Outerbridge grade III and no grade IV cartilage damage, and a stable and well-aligned knee. Different graft types have been used: viable, fresh frozen, cryopreserved, and lyophilized. The most common method for graft sizing was plain radiography. Different fixation techniques have been described, with only a few studies comparing the clinical results of the different techniques and with no proven superiority of one method over the other. All the studies showed clinical improvement at last follow-up visit compared with preoperatively. The chondroprotective effect of MAT is still unclear. Conclusion: Meniscal allograft transplantation seems to provide good clinical results at short-term and midterm follow-up, with improvement in knee function as well as acceptable complication and failure rates. Higher quality studies are necessary to better assess the potential chondroprotective effect of MAT and to identify differences in terms of outcomes between different surgical techniques. © 2015 The Author(s). Source

Gori F.,University of Rome Tor Vergata
Applied Thermal Engineering | Year: 2013

The mass and the energy-capital conservation equations are employed to study the time evolution of the mass of oil and the oil price evolution with time of the resources sold to the market in case of no-accumulation and no-depletion of the resources; i.e. when the resources are extracted and sold to the market at the same mass flow rate. The time evolution of the monthly oil price is studied from January 1994 until December 2013, investigating the detailed forecast resulting from the application of the present theory. The oil price can be reasonably forecasted using the prime and the discount rate interests as extreme limits. The method is then applied to forecast the oil price during months when the economic rates are still unknown. © 2013 Elsevier Ltd. All rights reserved. Source

Calleja R.,McGill University | Celletti A.,University of Rome Tor Vergata
Chaos | Year: 2010

We implement different methods for the computation of the breakdown threshold of invariant attractors in the dissipative standard mapping. A first approach is based on the computation of the Sobolev norms of the function parametrizing the solution. Then we look for the approximating periodic orbits and we analyze their stability in order to compute the critical threshold at which an invariant attractor breaks down. We also determine the domain of convergence of the dissipative standard mapping by extending the computations to the complex parameter space as well as by investigating a two-frequency model. © 2010 American Institute of Physics. Source

Cannarsa P.,University of Rome Tor Vergata | Frankowska H.,University Pierre and Marie Curie
Systems and Control Letters | Year: 2013

It is well-known that the value function V of a Bolza optimal control problem fails to be everywhere differentiable. In this paper, however, we show that, if V is proximally subdifferentiable at (t,x), then it is smooth on a neighborhood of (t,x). Our result yields that V stays smooth on a neighborhood of any optimal trajectory starting at a point where the proximal subdifferential is nonempty. This leads to sufficient conditions for the regularity of optimal trajectories and optimal controls. © 2013 Elsevier B.V. All rights reserved. Source

Hou H.,Aix - Marseille University | Di Vona M.L.,University of Rome Tor Vergata | Knauth P.,Aix - Marseille University
Journal of Membrane Science | Year: 2012

Biasco L.,San Raffaele Telethon Institute for Gene Therapy | Baricordi C.,San Raffaele Telethon Institute for Gene Therapy | Aiuti A.,San Raffaele Telethon Institute for Gene Therapy | Aiuti A.,University of Rome Tor Vergata
Molecular Therapy | Year: 2012

γ-Retroviral and lentiviral vectors allow the permanent integration of a therapeutic transgene in target cells and have provided in the last decade a delivery platform for several successful gene therapy (GT) clinical approaches. However, the occurrence of adverse events due to insertional mutagenesis in GT treated patients poses a strong challenge to the scientific community to identify the mechanisms at the basis of vector-driven genotoxicity. Along the last decade, the study of retroviral integration sites became a fundamental tool to monitor vector-host interaction in patients overtime. This review is aimed at critically revising the data derived from insertional profiling, with a particular focus on the evidences collected from GT clinical trials. We discuss the controversies and open issues associated to the interpretation of integration site analysis during patient's follow up, with an update on the latest results derived from the use of high-throughput technologies. Finally, we provide a perspective on the future technical development and on the application of these studies to address broader biological questions, from basic virology to human hematopoiesis. © The American Society of Gene & Cell Therapy. Source

Tomellini M.,University of Rome Tor Vergata
Journal of Materials Science | Year: 2013

The impact of soft impingement on the kinetics of diffusion-controlled growth of binary alloys is investigated. An analytical approach is developed which takes into account the process of island growth, that is the time dependence of the position of the nucleus/parent phase interface. The concentration profile, the growth law, and the kinetics of the fraction of transformed phase are computed and compared with those attained for point islands. At odd with the point island approach the local kinetics of growth depends on initial supersaturation. On the other hand, the whole transformation kinetics is in good agreement with that of the point island model with an Avrami exponent close to the theoretical value n = 0.5. The concentration profile is well described by a polynomial function in the whole spatial domain, with an exception for the initial stage of the phase separation. The effect of the spatial distribution of the nuclei on the kinetics is also studied in the model case of hard-core correlation among nuclei. © 2013 Springer Science+Business Media New York. Source

Anselmi M.,University of Rome La Sapienza | Di Nola A.,University of Rome La Sapienza | Amadei A.,University of Rome Tor Vergata
Journal of Physical Chemistry B | Year: 2011

Neuroglobin (Ngb) is a globular protein that reversibly binds small ligands at the six coordination position of the heme. With respect to other globins similar to myoglobin, Ngb displays some peculiarities as the topological reorganization of the internal cavities coupled to the sliding of the heme, or the binding of the endogenous distal histidine to the heme in the absence of an exogenous ligand. In this Article, by using multiple (independent) molecular dynamics trajectories (about 500 ns in total), the migration pathways of photolized carbon monoxide (CO) within solvated Ngb were analyzed, and a quantitative description of CO migration and corresponding kinetics was obtained. MD results, combined with quantum mechanical calculations on the CO-heme binding-unbinding reaction step in Ngb, allowed construction of a quantitative model representing the relevant steps of CO migration and rebinding. © 2011 American Chemical Society. Source

Sesti F.,University of Rome Tor Vergata
The journal of obstetrics and gynaecology research | Year: 2011

To compare postoperative outcomes and effects on quality of life following thermal balloon ablation (TBA) or laparoscopic supracervical hysterectomy (LSH) in women with heavy menstrual bleeding (HMB). Sixty-eight women requiring surgical treatment for HMB were randomly allocated into two treatment arms: TBA (n = 34) and LSH (n = 34). The randomization procedure was based on a computer-generated list. The primary outcome was a comparison of the effects on menstrual bleeding (Pictorial Blood Loss Assessment Chart [PBAC]) between the two procedures. The secondary outcome measures were quality of life, improvement of bleeding patterns, intensity of postoperative pain, and early postoperative complications. Continuous outcome variables were analyzed using Student's t-test. Discrete variables were analyzed with the χ2 test or Fisher's exact test. P < 0.05 was considered statistically significant. The PBAC score was significantly reduced in both treatment groups. After LSH all women had amenorrhea. After TBA there was a significant improvement of bleeding frequency and length. The postoperative pain intensity at 24 h was significantly minor in women treated with TBA rather than with LSH. The Medical Outcomes Survey Short Form 36 (SF-36) score improved in both groups. However, LSH showed a negative impact on the emotional state. No intraoperative complications occurred, and no case was returned to the theatre in either group. The effectiveness of TBA as a possible treatment of HMB is confirmed. However, LSH showed a definitive improvement of the symptoms, and a better life quality profile. Further controlled prospective studies are required for identifying the best surgical approach in women with HMB. © 2011 The Authors. Journal of Obstetrics and Gynaecology Research © 2011 Japan Society of Obstetrics and Gynecology. Source

Massaro F.,Smithsonian Astrophysical Observatory | Grindlay J.E.,Smithsonian Astrophysical Observatory | Paggi A.,University of Rome Tor Vergata
Astrophysical Journal Letters | Year: 2010

Gamma-ray bursts (GRBs) show evidence of different light curves, duration, afterglows, and host galaxies and explode within a wide redshift range. However, their spectral energy distributions (SEDs) appear to be very similar, showing a curved shape. Band etal. proposed a phenomenological description of the integrated spectral shape for the GRB prompt emission, the so-called Band function. In this Letter, we suggest an alternative scenario to explain the curved shape of GRB SEDs: the log-parabolic model. In comparison with the Band spectral shape our model is statistically favored because it fits the GRB spectra with one parameter less than the Band function and is motivated by a theoretical acceleration scenario. The new Fermi observations of GRBs will be crucial for disentangling these two models. © 2010. The American Astronomical Society. All rights reserved. Source

Bianchi D.,University of Rome Tor Vergata
International Urology and Nephrology | Year: 2016

Introduction: IgG4-related disease (IgG4-RD) is a recent nosological entity defined as a chronic immune-mediated fibro-inflammatory condition characterized by a tendency to form tumefactive, tissue-destructive lesions or by organ failure. Urologic involvement in IgG4-RD has been described in some short series of patients and in isolated case reports. Aim: The aim of the present study was to review urologic involvement in IgG4-RD with the purpose of providing urologists with the proper background necessary for a preliminary assessment of possible urologic localization of this recent clinical entity. Indeed, patients are typically referred for immunologic management, often right after a differential diagnosis of urologic disease. Materials and methods: A systematic search of PubMed® for both original and review articles published up until October 2015 was performed using keywords relating to IgG4 and to single specific urologic organs, structures, or anatomic sites. The search was then extended to Google® using the same search criteria in order to identify articles not indexed in PubMed®. Results: IgG4-RD is a systemic condition potentially involving every urologic site. It can mimic malignancies and is often misdiagnosed due to its rarity. Conclusions: A multidisciplinary approach to IgG4-RD should be required because it occasionally mimics other urologic diseases, including malignancies. Therefore, urologists should perform preliminary assessments to avoid inappropriate urologic treatments. © 2015, Springer Science+Business Media Dordrecht. Source

Rossolini G.M.,University of Siena | Thaller M.C.,University of Rome Tor Vergata
Genome Medicine | Year: 2010

Antibiotic resistance is a public health issue of global dimensions with a significant impact on morbidity, mortality and healthcare-associated costs. The problem has recently been worsened by the steady increase in multiresistant strains and by the restriction of antibiotic discovery and development programs. Recent advances in the field of bacterial genomics will further current knowledge on antibiotic resistance and help to tackle the problem. Bacterial genomics and transcriptomics can inform our understanding of resistance mechanisms, and comparative genomic analysis can provide relevant information on the evolution of resistant strains and on resistance genes and cognate genetic elements. Moreover, bacterial genomics, including functional and structural genomics, is also proving to be instrumental in the identification of new targets, which is a crucial step in new antibiotic discovery programs. © 2010 BioMed Central Ltd. Source

Gusynin V.P.,NASU Bogolyubov Institute for Theoretical Physics | Sharapov S.G.,NASU Bogolyubov Institute for Theoretical Physics | Varlamov A.A.,University of Rome Tor Vergata
Physical Review B - Condensed Matter and Materials Physics | Year: 2014

A strong spin Nernst effect with nontrivial dependences on the carrier concentration and electric field applied is expected in silicene and other low-buckled Dirac materials. These Dirac materials can be considered as being made of two independent electron subsystems of the two-component gapped Dirac fermions. For each subsystem, the gap breaks a time-reversal symmetry and thus plays the role of an effective magnetic field. Accordingly, the standard Kubo formalism has to be altered by including the effective magnetization in order to satisfy the third law of thermodynamics. We explicitly demonstrate this by calculating the magnetization and showing how the correct thermoelectric coefficient emerges. © 2014 American Physical Society. Source

Berrilli F.,University of Rome Tor Vergata
Frontiers in cellular and infection microbiology | Year: 2012

The interactions between intestinal microbiota, immune system, and pathogens describe the human gut as a complex ecosystem, where all components play a relevant role in modulating each other and in the maintenance of homeostasis. The balance among the gut microbiota and the human body appear to be crucial for health maintenance. Intestinal parasites, both protozoans and helminths, interact with the microbial community modifying the balance between host and commensal microbiota. On the other hand, gut microbiota represents a relevant factor that may strongly interfere with the pathophysiology of the infections. In addition to the function that gut commensal microbiota may have in the processes that determine the survival and the outcome of many parasitic infections, including the production of nutritive macromolecules, also probiotics can play an important role in reducing the pathogenicity of many parasites. On these bases, there is a growing interest in explaining the rationale on the possible interactions between the microbiota, immune response, inflammatory processes, and intestinal parasites. Source

Saggio G.,University of Rome Tor Vergata
Sensors and Actuators, A: Physical | Year: 2014

A new array of flex sensors was developed for integration into a sensory glove to perform goniometric semi-automated measurements. With this array, the sensory glove gained in repeatability of the measures, with respect to other gloves previously reported, performing with the lowest Range and Standard Deviation ever obtained. The reliability was notable, insofar the ICC averaged the "state of the art" sensory gloves. Performances and cheapness (tens of dollars) make this array particularly suitable for rehabilitation, when objective measures of the functional capabilities of subject's hand can be mandatory. © 2013 Elsevier B.V. Source

Fanelli P.,University of Tuscia | Vivio F.,University of Rome Tor Vergata
Theoretical and Applied Fracture Mechanics | Year: 2014

An analytical procedure for the evaluation of the elastic-plastic behaviour of spot welded joints, in terms of global stiffness is presented in this paper. The analytical procedure is based on a new reference theoretical model of the sheet region close to spot welded joint able to follow the evolution of plastic flow close to the joint. The new closed-form solutions allow to define the deflection of spot joint when an axial load is applied and plasticization occurred. The reference theoretical model is based on theory of elasticity and consists in a circular plate having two annular portions with different variable thickness and having a central rigid core representing the spot weld. This model allows to correctly simulate the actual plasticization radius when load increases and the global stiffness of the actual joint. The analytical procedure presented is new and lead to the definition of a spot weld finite element, able to precisely evaluate both local and overall stiffness of spot joints, also in elastic plastic field. This spot weld element lead to accurate simulation of multi spot welded structures with a very low computational effort. © 2014 Elsevier Ltd. Source

Arias De Fuentes O.,University of Habana | Ferri T.,University of Rome La Sapienza | Frasconi M.,University of Rome La Sapienza | Paolini V.,University of Rome La Sapienza | Santucci R.,University of Rome Tor Vergata
Angewandte Chemie - International Edition | Year: 2011

Tubes in file: Single-walled carbon nanotubes (SWNTs) were covalently anchored on different substrates by diazonium salt reactions (see picture). This unprecedented approach is highly versatile and leads to stable and well-organized SWCNT assemblies with potential for practical applications. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Source

Conti L.,University of Tuscia | Scardi M.,University of Rome Tor Vergata
Marine Ecology Progress Series | Year: 2010

Primary productivity (PP) and fisheries yield were analysed in 14 large marine ecosystems (LMEs), which encompassed temperate boreal shelves and the Eastern Boundary Currents (EBCs), from 1998 to 2002. PP was estimated by means of a depth-integrated neural network model based on Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data and aimed at providing conservative PP estimates. Landings records were extracted from the global spatial database provided by the Sea Around Us Project (SAUP). Correspondence analysis performed on yield data outlined the role played by different trophic levels (TLs) in LME catches. PP temporal variability was significantly and positively correlated to average trophic level of catches (TLc) so that higher yields in less variable ecosystems were characterised by a lower TLc. From a functional perspective, high PP temporal variability was associated preferentially with demersal fishes and lower yields, while pelagic-dominated catches were harvested in conditions with lower PP variability. Primary production required (PPR) to sustain fisheries in each LME showed that the highest yield occurred in combination with moderate fishing pressure especially when TLc was intermediate to low. High fishing pressures were associated with intermediate total yields and high TLc, a condition which seemed to occur in high-latitude boreal LMEs. The %PPR and TLc were used to assess fisheries impact on ecosystems. PP model choice affects the assessment of exploitation levels, in that a more conservative estimation of PP could contribute to a more precautionary approach to fisheries management where high levels of exploitation are more easily attained. Copyright © Inter-Research 2010. Source

Andreoni M.,University of Rome Tor Vergata
European review for medical and pharmacological sciences | Year: 2012

Hepatitis C virus (HCV) is the cause of more than three-quarters of liver-related deaths in HIV-seropositive individuals and it is remarkable that today approximately one-quarter of HIV-infected individuals in Europe and the USA have a HCV coinfection. HIV/HCV coinfected patients were more likely to develop cirrhosis, had an increased risk of developing AIDS, of HIV-related disease and of overall mortality. How HCV may affect the course of HIV infection is not well known even if it was suggested that HCV co-infection is able to increase immune activation and to sensitize CD4+ T-cells towards apoptosis in the absence of HIV therapy. There are many evidences that the simultaneous presence of HIV infection accelerates the liver damage from HCV favouring the evolution to cirrhosis in co-infected patients. HIV increasing of TNF alpha liver production and of HCV replication in peripheral blood lymphomonocytes are the mechanisms at the basis of this phenomenon. HAART had a positive effect on HIV/HCV co-infection, otherwise it does not appear to fully correct the adverse effect of HIV infection on HCV-related outcomes. Traditional treatment with pegilated Interferon plus ribavirin have low rates of sustained virological response in co-infected patients especially if infected with HCV genotype 1, and better results were often obtained in patients in which the use of antiretroviral treatment was avoided to reduce the occurrence of adverse effects. The recent preliminary results on the use of anti-HCV protease inhibitor drugs, boceprevir and telapravir, in co-infected people seems to demonstrate an enhanced antiviral efficacy in the HIV/HCV co-infected population of triple anti-HCV treatment even is some important limitation as interactions with antiretroviral agents and selection of HCV drug resistance, lead to consider the need for further studies designed to assess the best therapeutic strategies. Source

Breccia M.,University of Rome La Sapienza | Coco F.L.,University of Rome Tor Vergata | Coco F.L.,Laboratory of Neuro Oncohematology
Thrombosis Research | Year: 2014

Acute promyelocytic leukemia (APL) has become the most curable form of acute myeloid leukemia after the advent of all-trans retinoic acid (ATRA). However, early deaths (ED) mostly due to the disease-associated coagulopathy remain the major cause of treatment failure. In particular, hemorrhagic events account for 40-65% of ED and several prognostic factors have been identified for such hemorrhagic deaths, including poor performance status, high white blood cell (WBC) count and coagulopathy. Occurrence of thrombosis during treatment with ATRA may be associated with differentiation syndrome (DS) or represent an isolated event. Some prognostic factors have been reported to be associated with thrombosis, including increased WBC or aberrant immunophenotype of leukemic promyelocytes. Aim of this review is to report the incidence, severity, possible pathogenesis and clinical manifestations of thrombo-haemorrhagic deaths in APL. © 2014 Elsevier Ltd. All rights reserved. © 2014 Elsevier Ltd. Source

Poghossian R.,University of Rome Tor Vergata | Poghossian R.,Yerevan Physics Institute
Journal of High Energy Physics | Year: 2011

A system of Bethe-Ansatz type equations, which specify a unique array of Young tableau responsible for the leading contribution to the Nekrasov partition function in the ?2 → 0 limit is derived. It is shown that the prepotential with generic ?1 is directly related to the (rescaled by ?2) number of total boxes of these Young tableau. Moreover, all the expectation values of the chiral fields htr?J i are simple symmetric functions of their column lengths. An entire function whose zeros are determined by the column lengths is introduced. It is shown that this function satisfies a functional equation, closely resembling Baxter's equation in 2d integrable models. This functional relation directly leads to a nice generalization of the equation defining Seiberg-Witten curve. © SISSA 2011. Source

Bernardi M.,Massachusetts Institute of Technology | Palummo M.,Massachusetts Institute of Technology | Palummo M.,University of Rome Tor Vergata | Grossman J.C.,Massachusetts Institute of Technology
Nano Letters | Year: 2013

Graphene and monolayer transition metal dichalcogenides (TMDs) are promising materials for next-generation ultrathin optoelectronic devices. Although visually transparent, graphene is an excellent sunlight absorber, achieving 2.3% visible light absorbance in just 3.3 Å thickness. TMD monolayers also hold potential as sunlight absorbers, and may enable ultrathin photovoltaic (PV) devices due to their semiconducting character. In this work, we show that the three TMD monolayers MoS2, MoSe2, and WS2 can absorb up to 5-10% incident sunlight in a thickness of less than 1 nm, thus achieving 1 order of magnitude higher sunlight absorption than GaAs and Si. We further study PV devices based on just two stacked monolayers: (1) a Schottky barrier solar cell between MoS2 and graphene and (2) an excitonic solar cell based on a MoS2/WS2 bilayer. We demonstrate that such 1 nm thick active layers can attain power conversion efficiencies of up to ∼1%, corresponding to approximately 1-3 orders of magnitude higher power densities than the best existing ultrathin solar cells. Our work shows that two-dimensional monolayer materials hold yet untapped potential for solar energy absorption and conversion at the nanoscale. © 2013 American Chemical Society. Source

Nechache R.,University of Rome Tor Vergata | Harnagea C.,INRS - Institute National de la Recherche Scientifique | Li S.,INRS - Institute National de la Recherche Scientifique | Cardenas L.,INRS - Institute National de la Recherche Scientifique | And 4 more authors.
Nature Photonics | Year: 2014

Multiferroic films are increasingly being studied for applications in solar energy conversion because of their efficient ferroelectric polarization-driven carrier separation and above-bandgap generated photovoltages, which in principle can lead to energy conversion efficiencies beyond the maximum value ( 1/434%) reported in traditional silicon-based bipolar heterojunction solar cells. However, the efficiency reported so far is still too low (<2%) to be considered for commercialization. Here, we demonstrate a new approach to effectively tune the bandgap of double perovskite multiferroic oxides by engineering the cationic ordering for the case of Bi 2 FeCrO 6. Using this approach, we report a power conversion efficiency of 8.1% under AM 1.5 €.G irradiation (100 €.mW €.cm '2) for Bi 2 FeCrO 6 thin-film solar cells in a multilayer configuration. © 2014 Macmillan Publishers Limited. All rights reserved. Source

De Grijs R.,Peking University | Wicker J.E.,CAS National Astronomical Observatories | Bono G.,University of Rome Tor Vergata | Bono G.,National institute for astrophysics
Astronomical Journal | Year: 2014

The distance to the Large Magellanic Cloud (LMC) represents a key local rung of the extragalactic distance ladder yet the galaxy's distance modulus has long been an issue of contention, in particular in view of claims that most newly determined distance moduli cluster tightly - and with a small spread - around the "canonical" distance modulus, (m-M)0 = 18.50 mag. We compiled 233 separate LMC distance determinations published between 1990 and 2013. Our analysis of the individual distance moduli, as well as of their two-year means and standard deviations resulting from this largest data set of LMC distance moduli available to date, focuses specifically on Cepheid and RR Lyrae variable-star tracer populations, as well as on distance estimates based on features in the observational Hertzsprung-Russell diagram. We conclude that strong publication bias is unlikely to have been the main driver of the majority of published LMC distance moduli. However, for a given distance tracer, the body of publications leading to the tightly clustered distances is based on highly non-independent tracer samples and analysis methods, hence leading to significant correlations among the LMC distances reported in subsequent articles. Based on a careful, weighted combination, in a statistical sense, of the main stellar population tracers, we recommend that a slightly adjusted canonical distance modulus of (m-M)0 = 18.49 ± 0.09 mag be used for all practical purposes that require a general distance scale without the need for accuracies of better than a few percent. © 2014. The American Astronomical Society. All rights reserved. Source

De Mauro A.,University of Rome Tor Vergata | Greco M.,University of Cassino and Southern Lazio | Grimaldi M.,University of Cassino and Southern Lazio
AIP Conference Proceedings | Year: 2015

Although Big Data is a trending buzzword in both academia and the industry, its meaning is still shrouded by much conceptual vagueness. The term is used to describe a wide range of concepts: from the technological ability to store, aggregate, and process data, to the cultural shift that is pervasively invading business and society, both drowning in information overload. The lack of a formal definition has led research to evolve into multiple and inconsistent paths. Furthermore, the existing ambiguity among researchers and practitioners undermines an efficient development of the subject. In this paper we have reviewed the existing literature on Big Data and analyzed its previous definitions in order to pursue two results: first, to provide a summary of the key research areas related to the phenomenon, identifying emerging trends and suggesting opportunities for future development; second, to provide a consensual definition for Big Data, by synthesizing common themes of existing works and patterns in previous definitions. © 2015 AIP Publishing LLC. Source

Volonte C.,CNR Institute of Neuroscience | Apolloni S.,CNR Institute of Neuroscience | Carri M.T.,CNR Institute of Neuroscience | Carri M.T.,University of Rome Tor Vergata | D'Ambrosi N.,CNR Institute of Neuroscience
Pharmacology and Therapeutics | Year: 2011

Amyotrophic lateral sclerosis (ALS) is one of the most common neuromuscular diseases. It is devastating and fatal, causing progressive paralysis of all voluntary muscles and eventually death, while sparing cognitive functions. A pathological hallmark of ALS is neuroinflammation mediated by non-neuronal cells in the nervous system, such as microglia and astrocytes that accelerate the disease progression. Scientists have neither found a unique key mechanism, nor an effective treatment against ALS, supposedly because it is a multi-factorial and multi-systemic disease. Extracellular purines and pyrimidines are widespread and powerful physiopathological molecules, signalling to most cell types and directing cell-to-cell communication networks. They are instrumental for instance for neurotransmission, muscle contraction and immune surveillance. Recent work has reported the crucial involvement of purinergic pathways in many neurodegenerative and neuroinflammatory diseases, comprising ALS. Especially P2 receptors for ATP, P1 receptors for adenosine, and nucleotide transporters were found to be modulated in ALS cells and tissues, playing a potential role in the disease. Given the composite cellular cross-talk occurring during ALS and the established action of extracellular purines/pyrimidines as neuron-to-glia alarm signal in the nervous system, a mutual query in these two fields should now be whether, how and when purinergic would meet ALS. In this review, we will highlight the early cellular and molecular purinergic cross-talk that participates to ALS etiopathology, with the conviction that better understanding of purinergic dynamics might provide original research perspectives, stimulate alternative disease modelling, and the design and testing of more powerful targeted therapeutics against this relentlessly progressive disorder. © 2011 Elsevier Inc. Source

Fontini F.,University of Padua | Pavan G.,University of Rome Tor Vergata
Energy Policy | Year: 2014

We evaluate the contribution of technological change in reducing CO2 emissions in the Italian pulp and paper industry during the first and second phases of application of the European Union Emission Trading System (EU-ETS). We decompose the variation in emission and emission intensity into three different types of effects: a composition effect, a technique effect and a scale effect. The composition effect measures the change in emissions and emissions intensity due to a shift in production towards products that cause less emissions. The technique effect measures the change per each type of product, thereby accounting for technology improvements in the production of each type of good produced. The scale effect singles out the reduction in total emission due to an overall reduction in output. We show that the first phase of the application of EU-ETS has led to a reduction in both emissions and emission intensity due to the composition effect. The technological change has had a limited negative impact on emissions in the first phase, while in the second phase there has been limited technology improvement in the industry. However, the figures of the scale effect show that the larger reduction in emission is due to the overall decrease in output. © 2013 Elsevier Ltd. Source

Lunine J.I.,University of Rome Tor Vergata | Lunine J.I.,Istituto di Astrofisica Spaziale e Fisica Cosmica

The Cassini-Huygens mission discovered an active "hydrologic cycle" on Saturn's giant moon Titan, in which methane takes the place of water. Shrouded by a dense nitrogen-methane atmosphere, Titan's surface is blanketed in the equatorial regions by dunes composed of solid organics, sculpted by wind and fluvial erosion, and dotted at the poles with lakes and seas of liquid methane and ethane. The underlying crust is almost certainly water ice, possibly in the form of gas hydrates (clathrate hydrates) dominated by methane as the included species. The processes that work the surface of Titan resemble in their overall balance no other moon in the solar system; instead, they are most like that of the Earth. The presence of methane in place of water, however, means that in any particular planetary system, a body like Titan will always be outside the orbit of an Earth-type planet. Around M-dwarfs, planets with a Titan-like climate will sit at 1 AU - a far more stable environment than the ∼0.1 AU where Earth-like planets sit. However, an observable Titan-like exoplanet might have to be much larger than Titan itself to be observable, increasing the ratio of heat contributed to the surface atmosphere system from internal (geologic) processes versus photons from the parent star. © 2010 The Royal Society of Chemistry. Source

Meneely J.P.,Queens University of Belfast | Ricci F.,University of Rome Tor Vergata | van Egmond H.P.,RIKILT Institute of Food Safety | Elliott C.T.,Queens University of Belfast
TrAC - Trends in Analytical Chemistry | Year: 2011

This article describes the trends in analytical techniques for the determination of trichothecene mycotoxins, namely deoxynivalenol, and T-2 and HT-2 toxins in cereals and cereal products with particular emphasis on screening and rapid approaches. The driving force behind the changing methodologies is mainly attributed to legislative demands. However, for commercial and governmental testing laboratories, the need to use validated official methods is ever increasing to ensure quality assurance of results. Much research has been undertaken to improve screening assays, highlighted by the number of new methods using a variety of formats and platforms, including optical and electrochemical biosensors. Significant advances in the traditional reference methods have also been demonstrated in addition to the emergence of a variety of commercial immunoaffinity and solid-phase extraction columns for clean up. The use of liquid chromatography coupled to tandem mass spectrometry for mycotoxin detection is ever increasing, allowing simultaneous determination of many toxins in various sample matrices. © 2010 Elsevier Ltd. Source

Abramo G.,CNR Institute for System Analysis and Computer Science Antonio Ruberti | D'Angelo C.A.,CNR Institute for System Analysis and Computer Science Antonio Ruberti | D'Angelo C.A.,University of Rome Tor Vergata
Scientometrics | Year: 2014

Productivity is the quintessential indicator of efficiency in any production system. It seems it has become a norm in bibliometrics to define research productivity as the number of publications per researcher, distinguishing it from impact. In this work we operationalize the economic concept of productivity for the specific context of research activity and show the limits of the commonly accepted definition. We propose then a measurable form of research productivity through the indicator “Fractional Scientific Strength (FSS)”, in keeping with the microeconomic theory of production. We present the methodology for measure of FSS at various levels of analysis: individual, field, discipline, department, institution, region and nation. Finally, we compare the ranking lists of Italian universities by the two definitions of research productivity. © 2014, Akadémiai Kiadó, Budapest, Hungary. Source

Watkins H.M.,University of California at Santa Barbara | Simon A.J.,University of California at Santa Barbara | Ricci F.,University of Rome Tor Vergata | Plaxco K.W.,University of California at Santa Barbara
Journal of the American Chemical Society | Year: 2014

The high packing densities and fixed geometries with which biomolecules can be attached to macroscopic surfaces suggest that crowding effects may be particularly significant under these often densely packed conditions. Exploring this question experimentally, we report here the effects of crowding on the stability of a simple, surface-attached DNA stem-loop. We find that crowding by densely packed, folded biomolecules destabilizes our test-bed biomolecule by ∼2 kJ/mol relative to the dilute (noninteracting) regime, an effect that presumably occurs due to steric and electrostatic repulsion arising from compact neighbors. Crowding by a dense brush of unfolded biomolecules, in contrast, enhances its stability by ∼6 kJ/mol, presumably due to excluded volume and electrostatic effects that reduce the entropy of the unfolded state. Finally, crowding by like copies of the same biomolecule produces a significantly broader unfolding transition, likely because, under these circumstances, the stabilizing effects of crowding by unfolded molecules increase (and the destabilizing effects of neighboring folded molecules decrease) as more and more neighbors unfold. The crowding of surface-attached biomolecules may thus be a richer, more complex phenomenon than that seen in homogeneous solution. © 2014 American Chemical Society. Source

Watkins H.M.,University of California at Santa Barbara | Vallee-Belisle A.,University of California at Santa Barbara | Ricci F.,University of Rome Tor Vergata | Makarov D.E.,University of Texas at Austin | Plaxco K.W.,University of California at Santa Barbara
Journal of the American Chemical Society | Year: 2012

Surface-tethered biomolecules play key roles in many biological processes and biotechnologies. However, while the physical consequences of such surface attachment have seen significant theoretical study, to date this issue has seen relatively little experimental investigation. In response we present here a quantitative experimental and theoretical study of the extent to which attachment to a charged-but otherwise apparently inert-surface alters the folding free energy of a simple biomolecule. Specifically, we have measured the folding free energy of a DNA stem loop both in solution and when site-specifically attached to a negatively charged, hydroxylalkane-coated gold surface. We find that whereas surface attachment is destabilizing at low ionic strength, it becomes stabilizing at ionic strengths above ∼130 mM. This behavior presumably reflects two competing mechanisms: excluded volume effects, which stabilize the folded conformation by reducing the entropy of the unfolded state, and electrostatics, which, at lower ionic strengths, destabilizes the more compact folded state via repulsion from the negatively charged surface. To test this hypothesis, we have employed existing theories of the electrostatics of surface-bound polyelectrolytes and the entropy of surface-bound polymers to model both effects. Despite lacking any fitted parameters, these theoretical models quantitatively fit our experimental results, suggesting that, for this system, current knowledge of both surface electrostatics and excluded volume effects is reasonably complete and accurate. © 2012 American Chemical Society. Source

Desideri E.,University of Rome Tor Vergata | Martins L.M.,MRC Toxicology Unit
International Journal of Cell Biology | Year: 2012

Mitochondria are cellular energy generators whose activity requires a continuous supply of oxygen. Recent genetic analysis has suggested that defects in mitochondrial quality control may be key factors in the development of Parkinson's disease (PD). Mitochondria have a crucial role in supplying energy to the brain, and their deterioration can affect the function and viability of neurons, contributing to neurodegeneration. These organelles can sow the seeds of their own demise because they generate damaging oxygen-free radicals as a byproduct of their intrinsic physiological functions. Mitochondria have therefore evolved specific molecular quality control mechanisms to compensate for the action of damaging agents such as oxygen-free radicals. PTEN-induced putative kinase 1 (PINK1) and high-temperature-regulated A2 (HTRA2), a mitochondrial protease, have recently been proposed to be key modulators of mitochondrial molecular quality control. Here, we review some of the most recent advances in our understanding of mitochondria stress-control pathways, focusing on how signalling by the p38 stress kinase pathway may regulate mitochondrial stress by modulating the activity of HTRA2 via PINK1 and cyclin-dependent kinase 5 (CDK5). We also propose how defects in this pathway may contribute to PD. Copyright © 2012 Enrico Desideri and L. Miguel Martins. Source

Blackburn J.A.,Wilfrid Laurier University | Cirillo M.,University of Rome Tor Vergata | Gronbech-Jensen N.,University of California at Davis
Physics Reports | Year: 2016

For decades following its introduction in 1968, the resistively and capacitively shunted junction (RCSJ) model, sometimes referred to as the Stewart-McCumber model, was successfully applied to study the dynamics of Josephson junctions embedded in a variety of superconducting circuits. In 1980 a theoretical conjecture by A.J. Leggett suggested a possible new and quite different behavior for Josephson junctions at very low temperatures. A number of experiments seemed to confirm this prediction and soon it was taken as given that junctions at tens of millikelvins should be regarded as macroscopic quantum entities. As such, they would possess discrete levels in their effective potential wells, and would escape from those wells (with the appearance of a finite junction voltage) via a macroscopic quantum tunneling process. A zeal to pursue this new physics led to a virtual abandonment of the RCSJ model in this low temperature regime. In this paper we consider a selection of essentially prototypical experiments that were carried out with the intention of confirming aspects of anticipated macroscopic quantum behavior in Josephson junctions. We address two questions: (1) How successful is the non-quantum theory (RCSJ model) in replicating those experiments? (2) How strong is the evidence that data from these same experiments does indeed reflect macroscopic quantum behavior? © 2015 Elsevier B.V. Source

Adriano F.,Laboratory of Clinical and Behavioural Neurology | Caltagirone C.,Laboratory of Clinical and Behavioural Neurology | Caltagirone C.,University of Rome Tor Vergata | Spalletta G.,Laboratory of Clinical and Behavioural Neurology
Neuroscientist | Year: 2012

Several magnetic resonance imaging studies have reported hippocampal volume reduction in patients with schizophrenia, but other studies have reported contrasting results. In this review and meta-analysis, the authors aim to clarify whether a reduction in hippocampal volume characterizes patients with schizophrenia by considering illness phase (chronic and first episode) and hippocampus side separately. They made a detailed literature search for studies reporting physical volumetric hippocampal measures of patients with schizophrenia and healthy control (HC) participants and found 44 studies that were eligible for meta-analysis. Individual meta-analyses were also performed on 13 studies of first-episode patients and on 22 studies of chronic patients. The authors also detected any different findings when only males or both males and females were considered. Finally, additional meta-analyses and analyses of variance investigated the role of the factors "illness phase" and "side" on hippocampal volume reduction. Overall, the patient group showed significant bilateral hippocampal volume reduction compared with HC. Interestingly, first-episode and chronic patients showed same-size hippocampal volume reduction. Moreover, the left hippocampus was smaller than the right hippocampus in patients and HC. This review and meta-analysis raises the question about whether hippocampal volume reduction in schizophrenia is of neurodevelopmental origin. Future studies should specifically investigate this issue. © The Author(s) 2012. Source

Cattani G.,University of Rome Tor Vergata
Journal of Physics: Conference Series | Year: 2011

ATLAS (A Toroidal LHC ApparatuS) is one of the four experiments ready for p-p collisions scheduled in autumn 2009 at the LHC at CERN. It is a general purpose experiment, with a physics program that spans from the search of the Higgs Boson to the evidence of physics Beyond the Standard Model (BSM). Events with final state muons are a signature of the most promising physics channels, e.g. the Standard Model Higgs Boson decaying into four muons (H 4μ). For this reason a completely independent in-air Muon Spectrometer with a toroidal magnetic field for muon track measurement has been realized to trigger and measure the momentum of high energy muons. Resistive Plate Chambers (RPCs) provide the first-level muon trigger and the measurement of the coordinate in the non-bending direction in the barrel region of the Muon Spectrometer. The installation in the experimental hall of RPCs has been completed and extensive tests of their performance have been performed with cosmic-rays muons. An overview of the ATLAS experiment, focusing on the results of the studies on the RPCs performance will be presented. © Published under licence by IOP Publishing Ltd. Source

Vallee-Belisle A.,University of California at Santa Barbara | Ricci F.,University of Rome Tor Vergata | Ricci F.,Consorzio Interuniversitario Biostrutture e Biosistemi | Plaxco K.W.,University of California at Santa Barbara
Journal of the American Chemical Society | Year: 2012

Biomolecular recognition has long been an important theme in artificial sensing technologies. A current limitation of protein- and nucleic acid-based recognition, however, is that the useful dynamic range of single-site binding typically spans an 81-fold change in target concentration, an effect that limits the utility of biosensors in applications calling for either great sensitivity (a steeper relationship between target concentration and output signal) or the quantification of more wide-ranging concentrations. In response, we have adapted strategies employed by nature to modulate the input-output response of its biorecognition systems to rationally edit the useful dynamic range of an artificial biosensor. By engineering a structure-switching mechanism to tune the affinity of a receptor molecule, we first generated a set of receptor variants displaying similar specificities but different target affinities. Using combinations of these receptor variants (signaling and nonsignaling), we then rationally extended (to 900000-fold), narrowed (to 5-fold), and edited (three-state) the normally 81-fold dynamic range of a representative biosensor. We believe that these strategies may be widely applicable to technologies reliant on biorecognition. © 2011 American Chemical Society. Source

Laussy F.P.,University of Southampton | Kavokin A.V.,University of Southampton | Kavokin A.V.,University of Rome Tor Vergata | Shelykh I.A.,University of Iceland | Shelykh I.A.,St Petersburg Academic University
Physical Review Letters | Year: 2010

We revisit the exciton mechanism of superconductivity in the framework of microcavity physics, replacing virtual excitons as a binding agent of Cooper pairs by excitations of an exciton-polariton Bose-Einstein condensate. We consider a model microcavity where a quantum well with a two-dimensional electron gas is sandwiched between two undoped quantum wells, where a polariton condensate is formed. We show that the critical temperature for superconductivity dramatically increases with the condensate population, opening a new route towards high-temperature superconductivity. © 2010 The American Physical Society. Source

de Felici M.,University of Rome Tor Vergata
Molecular Human Reproduction | Year: 2010

At or early after birth, mammalian ovaries are filled with primordial follicles each composed by an oocyte blocked at the end of prophase I surrounded by a single layer of granulosa cells. The doctrine that female mammals are born with a finite number of oocytes fated to be exhausted with the age has been challenged by recent results claiming that new oocytes can be continuously formed in the post-natal mouse ovary. In my view, this notion, termed neo-oogenesis, is strictly linked to the process of the germline specification which presents unique features. Therefore, in the present paper, I am going to discuss two aspects of neo-oogenesis related to this process: first, evidence showing that adult mammalian ovary contains cells able to undergo germline specification and produce new oocytes; and second, the possible origin of such cells. In conclusion, I favour the possibility that a small number of primordial germ cells (PGCs)/oogonia or of PGC-derived undifferentiated cells with stem cell characteristics could remain in the post-natal ovary and under certain conditions may resume mitosis, enter meiosis and give rise to oocytes. © The Author 2010. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology. All rights reserved. Source

Busa R.,University of Rome Tor Vergata | Sette C.,Laboratory of Neuroembryology
RNA Biology | Year: 2010

Defects in the regulation of alternative splicing have strong relevance in the onset and progression of several types of human cancer. Modulation of alternative splicing allows cancer cells to adapt to hostile environments through production of specific mRNA variants. In particular, genotoxic stress exerted by chemotherapeutic drugs or irradiation strongly affects splicing of many genes. A key role in this aberrant regulation is played by the unbalanced expression of several splicing factors in cancer cells. Among them, the RNA-binding protein Sam68, which is overexpressed in various tumours, was shown to accumulate in nuclear foci of active transcription, together with other splicing regulators, and to affect splicing of target mRNAs in response to genotoxic stress. We suggest that subcellular redistribution of splicing factors is guided by changes in chromatin conformation elicited by DNA-damaging drugs. This event might represent an escape mechanism used by cancer cells to survive to genotoxic insults through expression of pro-survival, cancer-specific gene products. © 2010 Landes Bioscience. Source

Zaccarian L.,University of Rome Tor Vergata | Nesic D.,University of Melbourne | Teel A.R.,University of California at Santa Barbara
International Journal of Robust and Nonlinear Control | Year: 2011

In this paper we provide analytical and numerical Lyapunov functions that prove stability and performance of a First-order Reset Element (FORE) in feedback interconnection with a SISO linear plant. The Lyapunov functions also allow to establish finite gain ℓ2 stability from a disturbance input acting at the input of the plant to the plant output. ℓ2 stability is established by giving a bound on the corresponding ℓ2 gains. The proof of stability and performance is carried out by showing that the Lyapunov functions constructed here satisfy the sufficient conditions in the main results of Nešićet al. (Automatica 2008; 44(8):2019-2026). In the paper we also point out and illustrate via a counterexample an analysis subtlety overlooked in the preliminary results of Zaccarian et al. (American Control Conference, Portland, OR, U.S.A., 2005). © 2010 John Wiley & Sons, Ltd. Source

Efstathiou G.,Kavli Institute for Cosmology | Migliaccio M.,Kavli Institute for Cosmology | Migliaccio M.,University of Rome Tor Vergata
Monthly Notices of the Royal Astronomical Society | Year: 2012

We develop a model for the power spectrum of unresolved clusters of galaxies arising from the thermal Sunyaev-Zel'dovich (tSZ) effect. The model is based on a 'universal' gas pressure profile constrained by X-ray observations and includes a parameter to describe departures from self-similar evolution. The model is consistent with recent Planck observations of the tSZ effect for X-ray clusters with redshifts z≲ 1 and reproduces the low amplitude for the tSZ inferred from recent ground-based observations. By adjusting two free parameters, we are able to reproduce the tSZ power spectra from recent numerical simulations to an accuracy that is well within theoretical uncertainties. Our model provides a simple, empirically motivated tSZ template that may be useful for the analysis of new experiments such as Planck. © 2012 The Authors Monthly Notices of the Royal Astronomical Society © 2012 RAS. Source

Risso M.,University of Rome Tor Vergata
International Journal of Technology Management | Year: 2012

In the context of a globalised economy, many companies have adopted corporate social responsibility (CSR) strategies in their vertical relationships with suppliers whom they have asked to comply with their own codes of conduct. Thus, suppliers that enter into contractual relationships with such large companies may be confronted with multiple codes of conduct that incorporate different standards that they are expected to meet. This entails additional costs with consequential limited benefits. This paper focuses on large companies in specific sectors that operate in supply chains where they do not exert control over their suppliers and that are already promoting several collaborative initiatives among competitors to facilitate the identification of common standards across their supply chains. The descriptive and exploratory research includes a qualitative analysis of four cases, each of which explains an intra-sector collaborative approach to implementing CSR in international supply chains. Copyright © 2012 Inderscience Enterprises Ltd. Source

Kauppi L.,Sloan Kettering Cancer Center | Kauppi L.,University of Helsinki | Barchi M.,Sloan Kettering Cancer Center | Barchi M.,University of Rome Tor Vergata | And 5 more authors.
Genes and Development | Year: 2013

Different organisms display widely different numbers of the programmed double-strand breaks (DSBs) that initiate meiotic recombination (e.g., hundreds per meiocyte in mice and humans vs. dozens in nematodes), but little is known about what drives these species-specific DSB set points or the regulatory pathways that control them. Here we examine male mice with a lowered dosage of SPO11, the meiotic DSB catalyst, to gain insight into the effect of reduced DSB numbers on mammalian chromosome dynamics. An approximately twofold DSB reduction was associated with the reduced ability of homologs to synapse along their lengths, provoking prophase arrest and, ultimately, sterility. In many spermatocytes, chromosome subsets displayed a mix of synaptic failure and synapsis with both homologous and nonhomologous partners ("chromosome tangles"). The X chromosome was nearly always involved in tangles, and small autosomes were involved more often than large ones. We conclude that homolog pairing requirements dictate DSB set points during meiosis. Importantly, our results reveal that karyotype is a key factor: Smaller autosomes and heteromorphic sex chromosomes become weak links when DSBs are reduced below a critical threshold. Unexpectedly, unsynapsed chromosome segments trapped in tangles displayed an elevated density of DSB markers later in meiotic prophase. The unsynapsed portion of the X chromosome in wild-type males also showed evidence that DSB numbers increased as prophase progressed. These findings point to the existence of a feedback mechanism that links DSB number and distribution with interhomolog interactions. © 2013 by Cold Spring Harbor Laboratory Press. Source

Ghibelli L.,University of Rome Tor Vergata | Diederich M.,Laboratoire Of Biologie Moleculaire Et Cellulaire Du Cancer
Mitochondrion | Year: 2010

Bax is a pro-apoptotic protein allowing apoptosis to occur through the intrinsic, damage-induced pathway, and amplifying that one occurring via the extrinsic, receptor mediated pathway. Bax is present in viable cells and activated by pro-apoptotic stimuli. Activation implies structural changes, consisting of exposure of the N terminus and hydrophobic domains; changes in localization, consisting in migration from cytosol to mitochondria and endoplasmic reticulum membranes; changes in the aggregation status, from monomer to dimer and multimer. Bax has multiple critical domains, namely the N terminus exposed after activation; two hydrophobic stretches exposed for membrane anchorage; two reactive cysteines allowing multimerization; the BH3 domain for interactions with the Bcl-2 family members; alpha helix 1 for t-Bid interaction. Bax has also multiple functions: it releases different mitochondrial factors such as cytochrome c, SMAC/diablo; it regulates mitochondrial fission, the mitochondrial permeability transition pore; it promotes Ca2+ leakage through ER membrane. Altogether, Bax activation is a complex multi-step phenomenon. Here, we analyze these events as logically separable or alternative steps, attempting to assess their role, timing and reciprocal relation. © 2010 Mitochondria Research Society. Source

Bartolucci D.,University of Rome Tor Vergata
International Journal of Modern Physics D | Year: 2012

The equilibrium configurations of self-gravitating uniformly rotating isothermal cylinders in contact with a heat bath and their stability is studied by recently derived analytical techniques. The known critical temperature T c obtained by Katz and Lynden-Bell is found to be a stability threshold with respect to axially symmetric perturbations. We provide the almost explicit expression of negative specific heat solutions whose densities are sharply concentrated either near the symmetry axis or near some off-axis filaments as T → Tc-. The critical angular frequency observed numerically in literature is found to be the threshold value for the existence of these off-axis filaments. This is in striking contrast with the static case analyzed by Katz and Lynden-Bell where equilibrium configurations are found only if T > Tc and no negative specific heat equilibria exists at all. Metastability of the free energy's relative maximizers for T ≤ Tc is also discussed. Those off-axis configurations were predicted in the study of negative temperature states for guiding-centre plasmas and vortex systems. © 2012 World Scientific Publishing Company. Source

Horder J.,University of Oxford | Matthews P.,Milton Keynes Hospital | Waldmann R.,University of Rome Tor Vergata
Journal of Psychopharmacology | Year: 2011

Kirsch et al. (2008, Initial severity and antidepressant benefits: a meta-analysis of data submitted to the Food and Drug Administration. PLoS Med 5: e45), conducted a meta-analysis of data from 35 placebo controlled trials of four newer antidepressants. They concluded that while these drugs are statistically significantly superior to placebo in acute depression, the benefits are unlikely to be clinically significant. This paper has attracted much attention and debate in both academic journals and the popular media. In this critique, we argue that Kirsch et al.'s is a flawed analysis which relies upon unusual statistical techniques biased against antidepressants. We present results showing that re-analysing the same data using more appropriate methods leads to substantially different conclusions. However, we also believe that psychopharmacology has lessons to learn from the Kirsch et al. paper. We discuss issues surrounding the interpretation of clinical trials of antidepressants, including the difficulties of extrapolating from randomized controlled trials to the clinic, and the question of failed trials. We call for more research to establish the effectiveness of antidepressants in clinically relevant populations under naturalistic conditions, for example, in relapse prevention, in patients with co-morbidities, and in primary care settings. © The Author(s) 2011 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav. Source

Spalletta G.,Neuropsychiatry Laboratory | Piras F.,Neuropsychiatry Laboratory | Caltagirone C.,Neuropsychiatry Laboratory | Caltagirone C.,University of Rome Tor Vergata | Orfei M.D.,Neuropsychiatry Laboratory
Human Brain Mapping | Year: 2014

Lack of insight into illness is a multidimensional phenomenon that has relevant implications on clinical course and therapy compliance. Here, we focused on metacognitive insight in schizophrenia, that is, the ability to monitor one's changes in state of mind and sensations, with the aim of investigating its neuroanatomical, psychopathological, and neuropsychological correlates. Fifty-seven consecutive patients with Diagnostic and Statistical Manual of Mental Disorders (Fourth Edition, Text Revision) diagnosis of schizophrenia were administered the Insight Scale, and comprehensive psychopathological and neuropsychological batteries. They underwent a high-resolution T1-weighted magnetic resonance imaging investigation. Gray matter (GM) and white matter (WM) volumes were analyzed on a voxel-by-voxel basis using Statistical Parametric Mapping 8. Reduced metacognitive insight was related to reduced GM volumes in the left ventrolateral prefrontal cortex, right dorsolateral prefrontal cortex and insula, and bilateral premotor area and putamen. Further, it was related to reduced WM volumes of the right superior longitudinal fasciculum, left corona radiata, left forceps minor, and bilateral cingulum. Increased metacognitive insight was related to increased depression severity and attentional control impairment, while the latter was related to increased GM volumes in brain areas linked to metacognitive insight. Results of this study suggest that prefrontal GM and WM bundles, all implied in cognitive control and self-reflection, may be the neuroanatomical correlates of metacognitive insight in schizophrenia. Further, higher metacognitive insight is hypothesized to be a risk factor for depression which may subsequently impair attention. This line of research may provide the basis for the development of cognitive interventions aimed at improving self-monitoring and compliance to treatment. © 2014 Wiley Periodicals, Inc. Source

Capraro V.,Center for Mathematics and Computer Science | Marcelletti A.,University of Rome Tor Vergata
Scientific Reports | Year: 2014

Actions such as sharing food and cooperating to reach a common goal have played a fundamental role in the evolution of human societies. Despite the importance of such good actions, little is known about if and how they can spread from person to person to person. For instance, does being recipient of an altruistic act increase your probability of being cooperative with a third party? We have conducted an experiment on Amazon Mechanical Turk to test this mechanism using economic games. We have measured willingness to be cooperative through a standard Prisoner's dilemma and willingness to act altruistically using a binary Dictator game. In the baseline treatments, the endowments needed to play were given by the experimenters, as usual; in the control treatments, they came from a good action made by someone else. Across four different comparisons and a total of 572 subjects, we have never found a significant increase of cooperation or altruism when the endowment came from a good action. We conclude that good actions do not necessarily inspire good actions in others. While this is consistent with the theoretical prediction, it challenges the majority of other experimental studies. Source

Menasce D.A.,George Mason University | Casalicchio E.,University of Rome Tor Vergata | Dubey V.,George Mason University
Performance Evaluation | Year: 2010

Service Oriented Architectures enable a multitude of service providers to provide loosely coupled and interoperable services at different Quality of Service and cost levels. This paper considers business processes composed of activities that are supported by service providers. The structure of a business process may be expressed by languages such as BPEL and allows for constructs such as sequence, switch, while, flow, and pick. This paper considers the problem of finding the set of service providers that minimizes the total execution time of the business process subject to cost and execution time constraints. The problem is clearly NP-hard. However, the paper presents an optimized algorithm that finds the optimal solution without having to explore the entire solution space. This algorithm can be used to find the optimal solution in problems of moderate size. A heuristic solution is also presented. Thorough experimental studies, based on random business processes, demonstrate that the heuristic algorithm was able to produce service provider allocations that result in execution times that are only a few percentage points (less than 2.5%) worse than the allocations obtained by the optimal algorithm while examining a tiny fraction of the solution space (tens of points versus millions of points). © 2010 Elsevier B.V. All rights reserved. Source

Ercolani G.,University of Rome Tor Vergata
Tetrahedron Asymmetry | Year: 2014

The idea that an achiral receptor can promote asymmetric autocatalysis with amplification of chirality is presented and discussed in the light of two models, dubbed ACM1 and ACM2, corresponding to the autocatalytic versions of the classical Kagan and Noyori models for non-linear effects in asymmetric catalysis. The chiral amplifications produced by the two models have been investigated. The results suggest that an achiral receptor working according to the ACM1 model presents distinct advantages over the ACM2 counterpart, both in terms of elegance of design and performance. © 2014 Elsevier Ltd. All rights reserved. Source

Scagliarini A.,University of Rome Tor Vergata
Journal of Turbulence | Year: 2011

We study the statistics of curvature and torsion of Lagrangian trajectories from direct numerical simulations of homogeneous and isotropic turbulence (at Reλ ≈ 280) in order to extract informations on the geometry of small-scale coherent structures in turbulent flows. We find that, as previously observed by Braun et al. (W. Braun, F. De Lillo, and B. Eckhardt, Geometry of particle paths in turbulent flows, J. Turbul. 7 (2006), p. 62) and Xu et al. (H. Xu, N.T. Ouellette, and E. Bodenschatz, Curvature of Lagrangian trajectories in turbulence, Phys. Rev. Lett. 98 (2007), p. 050201), the high curvature statistics is dominated by large-scale flow reversals where velocity magnitude assumes very low values. We show that flow-reversal events are characterized by very short correlation times. We introduce both time filtering and threshold in the minimum velocity amplitude in order to disentangle intense curvature events generated from genuine small-scale vortex structures from simple flow-reversal.We present for the first time measurements of torsion statistics in fully developed turbulent flows. By studying the joint statistics of curvature and torsion, we present further evidences that intense and persistent events are dominated by helical-type trajectories. © 2011 Taylor & Francis. Source

Viaggiu S.,University of Rome Tor Vergata
International Journal of Modern Physics D | Year: 2016

In this paper, we continue the study of the physical consequences of our modified black hole entropy formula in expanding spacetimes. In particular, we apply the new formula to apparent horizons of Friedmann expanding universes with zero, negative and positive spatial curvature. As a first result, we found that apart from the static Einstein solution, the only Friedmann spacetimes with constant (zero) internal energy are the ones with zero spatial curvature. This happens because, in the computation of the internal energy U, the contribution due to the nonvanishing Hubble flow must be added to the usual Misner-Sharp energy giving, for zero curvature spacetimes, a zero value for U. This fact does not hold when curvature is present. After analyzing the free energy F, we obtain the correct result that F is stationary only for physical systems in isothermal equilibrium, i.e. a de Sitter expanding universe. This result permits us to trace back a physically reasonable hypothesis concerning the origin of the early and late times de Sitter phase of our universe. Finally, we deduce an interesting temperature-length inequality similar to the time-energy uncertainty of ordinary quantum mechanics but with temperature instead of time coordinate. Remarkably, this relation is independent of the gravitational constant G and can thus be explored also in nongravitational contexts. © 2016 World Scientific Publishing Company. Source

Cherubini S.,University of Rome Tor Vergata | Iasevoli G.,University | Michelini L.,University
Journal of Cleaner Production | Year: 2015

In the electric car industry the service component assumes considerable importance and it is a relevant factor in purchasing decisions. Therefore, proper management of the "Product-Service System" (PSS) is essential. This article aims to 1) identify the main sub-systems of the PSS in the electric car industry and 2) identify the critical success factors (CSFs) in marketing. The review of the literature led to the definition of four sub-systems: vehicle, infrastructure, on-board electronics, and energy. Based on these PSS sub-systems, organisations belonging to each sub-system were selected, and five managers were interviewed. The data were analysed using a cognitive mapping technique. Ten CSFs were identified, of which two belong to the vehicle sub-system (value proposition and product-service system bundle); one relates to the electronic on-board sub-system (advanced navigation systems); three relate to infrastructure sub-system (incentives, alternative transport systems and advocacy campaigns) and three belong to infrastructure and energy sub-systems (ease of use, proximity of charging point and standardisation). Finally, partnerships among players involve all the four sub-systems. Moreover, the relevance/manageability matrix offers evidence that partnerships represent a priority factor that requires immediate action from companies. The research offers a new means to identify CSFs by using a PSS analysis rather than taking an industry sector perspective. © 2014 Elsevier Ltd. Source

Carbone M.,University of Rome Tor Vergata | Quaroni L.,Paul Scherrer Institute
Biochimica et Biophysica Acta - General Subjects | Year: 2013

Background The pH of a biological system is a crucial determinant of the structures and reactivity of its components and cellular homeostasis of H + is critical for cell viability. Control and monitoring of cellular acidity are highly desirable for the purpose of studying biochemical processes in vivo. Methods The effect of photolysis of a caged strong acid, the ester 1-(2-nitrophenyl)-ethylhexadecyl sulfonate (HDNS) is used to cause a controlled drop in pH in single cells. An isolated cell is selected under the IR microscope, irradiated with near-UV light and monitored by FTIR. Results We demonstrate the use of FTIR spectromicroscopy to monitor light-induced acidification of the cellular medium by measuring the increased concentration of CO2 and corresponding decrease of HCO3 - in the cell and in the surrounding medium. Conclusions We have demonstrated a method to control and accurately monitor the changes in pH of a cellular system by coupling a caged proton-releasing agent with FTIR spectromicroscopy detection. The overall implementation of photolysis and spectroscopic detection in a microscope optical configuration ensures single cell selectivity in both acidification and monitoring. We show the viability of monitoring of pH changes by FTIR spectromicroscopy with sensitivity comparable to that of glass electrodes, better than the existing methods for determining cell pH. General significance Reporting the effect of small variations of cellular acidity provides a major improvement in the understanding of the interplay between molecular properties as assessed in vitro and cell physiology. © 2013 Elsevier B.V. Source

Russo F.,University of Reggio Calabria | Comi A.,University of Rome Tor Vergata
Transportation | Year: 2010

The paper reports a modelling system to simulate goods movements at an urban scale. It allows joint analysis of choices made by end-consumers (assumed to be families) and retailers. These movements are examined at two levels: analysis of commodity flows, in terms of quantity, generated by the consumption of commodities; analysis of commodity flows, in terms of vehicles, due to restocking. The first level allows us to calculate the goods quantity flows due to consumption and restocking; the second level allows us to determine the service, vehicles used and target time, as well as the route chosen for restocking sales outlets in order to estimate vehicle flows on the urban/metropolitan transportation network. The modelling system is a multi-step model and considers a disaggregated approach for each decisional level. © 2010 Springer Science+Business Media, LLC. Source

Calogero G.,CNR Institute for Chemical and Physical Processes | Bartolotta A.,CNR Institute for Chemical and Physical Processes | Di Marco G.,CNR Institute for Chemical and Physical Processes | Di Carlo A.,University of Rome Tor Vergata | Bonaccorso F.,Italian Institute of Technology
Chemical Society Reviews | Year: 2015

There is currently a large effort to improve the performance of low cost renewable energy devices. Dye-sensitized solar cells (DSSCs) are emerging as one of the most promising low cost photovoltaic technologies, addressing "secure, clean and efficient solar energy conversion". Vegetable dyes, extracted from algae, flowers, fruit and leaves, can be used as sensitizers in DSSCs. Thus far, anthocyanin and betalain extracts together with selected chlorophyll derivatives are the most successful vegetable sensitizers. This review analyses recent progress in the exploitation of vegetable dyes for solar energy conversion and compares them to the properties of synthetic dyes. We provide an in-depth discussion on the main limitation of cell performance e.g. dye degradation, effective electron injection from the dye into the conduction band of semiconducting nanoparticles, such as titanium dioxide and zinc oxide, outlining future developments for the use of vegetable sensitizers in DSSCs. We also discuss the cost of vegetable dyes and how their versatility can boost the advancement of new power management solutions, especially for their integration in living environments, making the practical application of such systems economically viable. Finally, we present our view on future prospects in the development of synthetic analogues of vegetable dyes as sensitizers in DSSCs. This journal is © The Royal Society of Chemistry. Source

Barletta M.,University of Rome Tor Vergata | Bellisario D.,University of Rome La Sapienza
Progress in Organic Coatings | Year: 2011

The present investigation analyzes the deformation behaviour under static and dynamic loading conditions of electrostatically sprayed epoxy-polyester powder coatings by local and uniaxial tests, trying to account for the separate contribution of the raw polymeric material alone and of the adhesion to the underlying metal substrate. First, thermo-rheological properties of the basic material (i.e., the thermosetting powder paints) were characterized by differential scanning calorimetry (DSC) and rheometry. Secondly, free-standing films were manufactured by electrostatic spraying of the thermosetting powders onto stainless steel substrates pre-coated with an intermediate layer of silicon-based heat curable release coating. The resulting free standing-films were macroscopically characterized by combined dynamic-mechanical analyses (DMA) and tensile tests. Finally, local mechanical characterization of the coating performance was carried out by micro-scale depth sensing scratch and indentation on coatings 'free-standing' and 'rigidly adhering' onto metal substrate. The experimental findings show the different mechanical behaviour of the polymeric coatings, whose thermal, rheological, dynamical properties were fully characterized, when deposited on untreated or pre-treated substrates as well as on intermediate layers of release coating, thus contributing to better understand how much of the coating properties are ascribable to the material chosen or to the interfacial adhesion between coating and substrate. © 2010 Elsevier B.V. All rights reserved. Source

Chiricozzi A.,Rockefeller University | Chiricozzi A.,University of Rome Tor Vergata | Krueger J.G.,Rockefeller University
Expert Opinion on Investigational Drugs | Year: 2013

Introduction: Psoriasis is a chronic, disabling, inflammatory skin disease whose pathogenesis still remains to be fully elucidated. Genetic and environmental factors induce an immune response mediated by several cytokines and chemokines, including IL-17A. Areas covered: Emerging evidence now suggests that IL-17A is central in the pathogenesis of psoriasis. Three agents neutralizing IL-17 (i.e., secukinumab and ixekizumab) or antagonizing its receptor (i.e., brodalumab) are in development and are being studied in Phase III clinical trials to evaluate their overall efficacy and safety. However, Phase II results of IL-17 blockade with each of these agents has shown a marked improvement of disease severity, thus confirming the pathogenic relevance of IL-17 in mediating crucial inflammatory circuits in psoriasis. Expert opinion: Anti-IL-17 agents are likely to become important future therapeutics in this disease and the may potentially impact on cardiovascular diseases, arthritis and other comorbidities associated with psoriasis. © 2013 Informa UK, Ltd. Source

Lhotka C.,University of Vienna | Celletti A.,University of Rome Tor Vergata
Icarus | Year: 2015

We investigate the stability of motion close to the Lagrangian equilibrium points L4 and L5 in the framework of the spatial, elliptic, restricted three-body problem, subject to the radial component of Poynting-Robertson drag. For this reason we develop a simplified resonant model, that is based on averaging theory, i.e. averaged over the mean anomaly of the perturbing planet. We find temporary stability of particles displaying a tadpole motion in the 1:1 resonance. From the linear stability study of the averaged simplified resonant model, we find that the time of temporary stability is proportional to βa1n1, where β is the ratio of the solar radiation over the gravitational force, and a1, n1 are the semi-major axis and the mean motion of the perturbing planet, respectively. We extend previous results (Murray, C.D. [1994]. Icarus 112, 465-484) on the asymmetry of the stability indices of L4 and L5 to a more realistic force model. Our analytical results are supported by means of numerical simulations. We implement our study to Jupiter-like perturbing planets, that are also found in extra-solar planetary systems. © 2014 Elsevier Inc. Source

Barletta M.,University of Rome Tor Vergata
Progress in Organic Coatings | Year: 2011

Metal-flake powder coatings are a special class of metallic paint finishes composed of two superimposed layers: a pigmented decorative base coat and an overlaying transparent protective top coat. In the present investigation, a novel curing procedure for such bilayer coatings is proposed. Flash IR pre-curing of the base coat promotes the formation of a surface diffusion barrier and limits movement of the decorative pigments and metal flakes around their initial positions. Oven baking after deposition of the top coat then completes curing of the bilayer coating. The influence of the IR intensity and irradiation time on the final properties of bilayer coatings was investigated. The visual appearance, surface morphology and scratch resistance were evaluated. Experimental findings revealed that the hybrid IR/oven baking curing procedure is a viable method for obtaining bilayer powder coatings with outstanding properties in a shorter processing time and with considerable energy savings. © 2011 Elsevier B.V. Source

Cascetta E.,University of Naples Federico II | Coppola P.,University of Rome Tor Vergata
Transportation Research Part A: Policy and Practice | Year: 2016

Despite some substantial limitations in the simulation of low-frequency scheduled services, frequency-based (FB) assignment models are by far the most widely used in practice. They are less expensive to build and less demanding from the computational viewpoint with respect to schedule-based (SB) models, as they require neither explicit simulation of the timetable (on the supply side), nor segmentation of OD matrices by desired departure/arrival time (on the demand side).The objective of this paper is to assess to what extent the lack of modeling capabilities of FB models is acceptable, and, on the other hand, the cases in which such approximations are substantial and more detailed SB models are needed. This is a first attempt to shed light on the trade-off between (frequency-based) model inaccuracy and (scheduled-based) model development costs in the field of long-distance (e.g. High-speed Rail, HSR) service modeling.To this aim, we considered two modeling specifications estimated using mixed Revealed Preferences (RP) and Stated Preferences (SP) surveys and validated with respect to the same case study. Starting from an observed (baseline) scenario, we artificially altered the demand distributions (uniform vs. time-varying demand) and the supply configuration (i.e. train departure times), and analyzed the differences in modal split estimates and flows on individual trains, using the two different model specifications.It resulted that when the demand distribution is uniform within the period of analysis, such differences are significant only when departure times of trains are strongly unevenly spaced in time. In such cases, the difference in modal shares, using FB w.r.t. SB, is in the range of [0%, +5%] meaning that FB models tend to overestimate HSR modal shares. When the demand distribution is not uniform, the difference in modal shares, using FB w.r.t. SB, is in the range of [-10%, +10%] meaning that FB models can overestimate or underestimate HSR modal shares, depending on timetable settings with respect to travelers' desired departure times. The differences in on-board train flow estimates are more substantial in both cases of uniform and not uniform demand distribution. © 2015 Elsevier Ltd. Source

Dolgopyat D.,University of Maryland University College | Liverani C.,University of Rome Tor Vergata
Communications in Mathematical Physics | Year: 2011

We consider a finite region of a lattice of weakly interacting geodesic flows on manifolds of negative curvature and we show that, when rescaling the interactions and the time appropriately, the energies of the flows evolve according to a nonlinear diffusion equation. This is a first step toward the derivation of macroscopic equations from a Hamiltonian microscopic dynamics in the case of weakly coupled systems. © 2011 Springer-Verlag. Source

Piancastelli L.,University of Bologna | Frizziero L.,University of Bologna | Pezzuti E.,University of Rome Tor Vergata
ARPN Journal of Engineering and Applied Sciences | Year: 2014

Surprisingly, the safety of a flight is still not guaranteed to maximum steam ejection of power during take-off. Moreover, modern aircraft require significant amounts of electricity. It could also be argued that today in many respects the automotive industry appears to be a technology leader with respect to the aerospace industry that, instead, is more conservative. Ferrari has developed, and implemented, on their F1 cars, an electronic device, called KERS, which is able to produce electricity, with peaks of 60 KW for 7s, with a mass of 20 kg, including rechargeable batteries. The main goal of this paper is to explore utilization of turbo-charged aerodiesel engines and conduct feasibility study of the F1-derived KERS to assist power generation in normal and critical flight phases. The KERS' reversible brushless electric motor works as a generator for all aircraft power needs and also provides starting power. It is demonstrated here that such design philosophy improves performance and flight safety of light-to-medium airplanes and helicopter. © 2006-2014 Asian Research Publishing Network (ARPN). Source

Iacobelli S.,University of Rome Tor Vergata
Bone Marrow Transplantation | Year: 2013

This document explains some of the relevant methodological issues involved in planning a clinical study using survival and time-to-event outcome data, particularly in the field of haematopoietic stem cell transplantation, and indicates the appropriate statistical methods to use for the analysis. As the majority of these methods are commonly used in survival and event-history analysis, this document discusses their potential and limitations with reference to common SCT research situations. Some reference is given to methods, recently appearing in the literature that may be capable of handling complex investigations. These guidelines also address various practical issues, such as recoding or transforming variables in regression models or reporting results. © 2013 Macmillan Publishers Limited All rights reserved. Source

Patrizi L.,University of Rome Tor Vergata
Diagnostic pathology | Year: 2013

The "proximal-type" epithelioid sarcoma is a very rare kind of mesenchimal tumor characterized by the difficulty in histological diagnosis and the very aggressive biological behavior. We report of a case of a 63 years old woman with a vulvar "proximal-type" epithelioid sarcoma that underwent a radical surgical staging followed by an adjuvant radiotherapy. She is on follow-up care for 14 months and there is no clinical evidence of disease. Even if quite rare the proximal type epithelioid sarcoma should be regarded as a separate entity of particularly aggressive biologic behaviour. Its diagnosis attracts controversies and criticism related to the surgical approach and the choice of an adjuvant therapy. The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1508554852942125. Source

Luciano D.E.,Center for Fertility and Womens Health | Exacoustos C.,University of Rome Tor Vergata | Johns D.A.,University of Texas Southwestern Medical Center | Luciano A.A.,Center for Fertility and Womens Health
American Journal of Obstetrics and Gynecology | Year: 2011

OBJECTIVE: The objective of the study was to assess the accuracy of hysterosalpingo-contrast sonography (HyCoSy) in establishing tubal patency or blockage and evaluating the uterine cavity by comparing it with hysteroscopy laparoscopy (HLC) or hysterosalpingography (HSG). STUDY DESIGN: This study was a chart review evaluating infertility patients and patients who had undergone hysteroscopic sterilization who underwent both HyCoSy and HLC or HyCoSy and HSG at private offices associated with university hospitals. Sensitivity, specificity, positive predictive value, and negative predictive value of HyCoSy were calculated. RESULTS: HyCoSy compared with HLC had a sensitivity of 97% and specificity of 82%, and HyCoSy compared with HSG was 100% concordant. Uterine cavities evaluated by sonohysterography and hysteroscopy were 100% concordant. CONCLUSION: HyCoSy is accurate in determining tubal patency and evaluating the uterine cavity, suggesting it could supplant HSG not only as the first-line diagnostic test in an infertility workup but also in confirming tubal blockage after hysteroscopic sterilization. © 2011 Mosby, Inc. Source

Mineo T.C.,University of Rome Tor Vergata
Oncology (Williston Park, N.Y.) | Year: 2012

Malignant pleural mesothelioma (MPM) is a highly severe primary tumor of the pleura mainly related to exposure to asbestos fibers. The median survival after symptom onset is less than 12 months. Conventional medical and surgical therapies--either as single lines or combined--are not wholly effective. No universally accepted guidelines have yet been established for patient selection and the use of therapeutic strategies. In addition, retrospective staging systems have proved inadequate at improving therapeutic outcomes. Therapy is currently guided by gross tumor characteristics and patient features; however, these seem less accurate than the biological fingerprint of the tumor. A number of clinical prognostic factors have been considered in large multicenter series and independently validated. A series of novel biomarkers can predict the evolution of the disease. Here we summarize the principal and novel factors that influence prognosis and are thus potentially useful for selecting patients for targeted therapy. Source

Carlino C.,University of Rome Tor Vergata
Igiene e sanità pubblica | Year: 2012

Vaccines represent the most effective and economical tools available in the field of Public Health. The use of vaccines led to profound changes in the epidemiology of many infectious diseases, reducing their morbidity and mortality. Adults became specific target of immunization strategies in the last decades. In this paper, the factors affecting their acceptance of vaccinations were analyzed, using the examples of the widely discussed vaccinations against HPV and flu. Source

Castillo-Rogez J.C.,Jet Propulsion Laboratory | Lunine J.I.,University of Rome Tor Vergata
Geophysical Research Letters | Year: 2010

We model the thermal evolution of Titan's core and search for solutions that are consistent with the mean moment of inertia yielded by the Cassini-Huygens Mission. Like previous studies we assume that Titan's core is enriched in hydrated silicates. However, our modeling accounts for the possible dehydration of these minerals. The resulting models are consistent with Titan's moment of inertia if the inner dry silicate core remains smaller than ∼1300 km in radius. This constraint is met if at least 30% of potassium was leached from the silicate during the hydration event, i.e., the core is depleted in one of its major heat source. In this scenario, the core is currently undergoing dehydration. © 2010 by the American Geophysical Union. Source

Tarisciotti L.,University of Nottingham | Zanchetta P.,University of Nottingham | Watson A.,University of Nottingham | Bifaretti S.,University of Rome Tor Vergata | Clare J.C.,University of Nottingham
IEEE Transactions on Industrial Electronics | Year: 2014

Multilevel converters are known to have many advantages for electricity network applications. In particular, cascaded H-bridge converters are attractive because of their inherent modularity and scalability. Predictive control for power converters is advantageous as a result of its applicability to discrete system and fast response. In this paper, a novel control technique, named modulated model predictive control, is introduced with the aim to increase the performance of model predictive control. The proposed controller addresses a modulation scheme as part of the minimization process. The proposed control technique is described in detail, validated through simulation and experimental testing, and compared with dead-beat and traditional model predictive control. The results show the increased performance of the modulated model predictive control with respect to the classic finite control set model predictive control in terms of current waveform total harmonic distortion (THD). Moreover, the proposed controller allows a multi-objective control, with respect to dead-beat control that does not present this capability. © 1982-2012 IEEE. Source

Rossi G.C.,University of Rome Tor Vergata | Testa M.,University of Rome La Sapienza
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

We show how to define and compute in a nonperturbative way the potential between q and q̄ color sources in the singlet and octet (adjoint) representations of the color group. © 2013 American Physical Society. Source

De Felici M.,University of Rome Tor Vergata | Barrios F.,University of Cambridge
Reproduction | Year: 2013

The function of female germline stem cells (FGSCs, also called oogonial stem cells) in the adult mammalian ovary is currently debated in the scientific community. As the evidence to support or discard the possible crucial role of this new class of germ cells in mammals has been extensively discussed, in this review, we wonder which could be their origin. We will assume that FGSCs are present in the post-natal ovaries and speculate as to what origin and characteristics such cells could have. We believe that the definition of these features might shed light on future experimental approaches that could clarify the ongoing debate. © 2013 Society for Reproduction and Fertility. Source

Stevens R.J.A.M.,University of Twente | Verzicco R.,University of Rome Tor Vergata | Lohse D.,University of Twente
Journal of Fluid Mechanics | Year: 2010

Results from direct numerical simulation (DNS) for three-dimensional RayleighBnard convection in a cylindrical cell of aspect ratio 1/2 and Prandtl number Pr=0.7 are presented. They span five decades of Rayleigh number Ra from 2 106 to 2 × 1011. The results are in good agreement with the experimental data of Niemela et al. (Nature, vol. 404, 2000, p. 837). Previous DNS results from Amati et al. (Phys. Fluids, vol. 17, 2005, paper no. 121701) showed a heat transfer that was up to 30% higher than the experimental values. The simulations presented in this paper are performed with a much higher resolution to properly resolve the plume dynamics. We find that in under-resolved simulations the hot (cold) plumes travel further from the bottom (top) plate than in the better-resolved ones, because of insufficient thermal dissipation mainly close to the sidewall (where the grid cells are largest), and therefore the Nusselt number in under-resolved simulations is overestimated. Furthermore, we compare the best resolved thermal boundary layer profile with the PrandtlBlasius profile. We find that the boundary layer profile is closer to the PrandtlBlasius profile at the cylinder axis than close to the sidewall, because of rising plumes close to the sidewall. © 2009 Cambridge University Press. Source

Sbragaglia M.,University of Rome Tor Vergata | Shan X.,Exa Corporation
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2011

We outline a systematic procedure on how to construct and derive interactions for nonideal lattice fluids. Using a mesoscopic approach based on exact lattice theories, we prove the consistency of the resulting diffuse interface theory with continuum thermodynamics. Translated in the framework of the so called "Shan-Chen" model for nonideal lattice fluids, this paper shows how to adjust the associated pseudopotentials to reproduce a free energy model based on a square gradient theory of equilibrium interfaces. © 2011 American Physical Society. Source

Longo R.,University of Rome Tor Vergata | Witten E.,Institute for Advanced Study
Communications in Mathematical Physics | Year: 2011

We build up local, time translation covariant Boundary Quantum Field Theory nets of von Neumann algebras Av on the Minkowski half-plane M+ starting with a local conformal net of von Neumann algebras on ℝ and an element V of a unitary semigroup ε(A) associated with A. The case V = 1 reduces to the net A+ considered by Rehren and one of the authors; if the vacuum character of A is summable, A+ is locally isomorphic to ε(A). We discuss the structure of the semigroup ε(A). By using a one-particle version of Borchers theorem and standard subspace analysis, we provide an abstract analog of the Beurling-Lax theorem that allows us to describe, in particular, all unitaries on the one-particle Hilbert space whose second quantization promotion belongs to ε(A(0)) with A(0) the U(1)-current net. Each such unitary is attached to a scattering function or, more generally, to a symmetric inner function. We then obtain families of models via any Buchholz-Mack-Todorov extension of A(0). A further family of models comes from the Ising model. © 2010 Springer-Verlag. Source

Vallee-Belisle A.,University of California at Santa Barbara | Bonham A.J.,University of California at Santa Barbara | Reich N.O.,University of California at Santa Barbara | Ricci F.,University of Rome Tor Vergata | Plaxco K.W.,University of California at Santa Barbara
Journal of the American Chemical Society | Year: 2011

The development of convenient, real-time probes for monitoring protein function in biological samples represents an important challenge of the postgenomic era. In response, we introduce here "transcription factor beacons," binding-activated fluorescent DNA probes that signal the presence of specific DNA-binding activities. As a proof of principle, we present beacons for the rapid, sensitive detection of three transcription factors (TATA Binding Protein, Myc-Max, and NF-κB), and measure binding activity directly in crude nuclear extracts. © 2011 American Chemical Society. Source

Conti R.,International School for Advanced Studies | Viggiani G.M.B.,University of Rome Tor Vergata
Journal of Geotechnical and Geoenvironmental Engineering | Year: 2012

This paper describes a method to compute the mobilized shear modulus, G, and damping ratio, D, using the nonlinear fit of experimental transfer functions obtained at different depths in centrifuge models, with the analytical expression of the amplification function for a viscoelastic soil layer on a rigid base. The corresponding shear strain,γ, is computed as a function of the particle velocity and shear wave velocity. The sources of potential error in the determination of G, D, and γ embedded in the proposed method are identified and discussed in comparison with two other methods that have been proposed in the literature, based either on the determination of the time lag of accelerations between two accelerometers or on the evaluation of the shear stress-strain cycles from acceleration time histories recorded at different depths in the model. The performance of the threemethods is evaluated using the experimental data obtained from nine centrifuge tests on dry sand. The values of G obtained by the proposed method compare well with the results oflaboratory and literature data; D values are more dispersed and slightly higher than the literature data. © 2012 American Society of Civil Engineers. Source

Cannuccia E.,University of Rome Tor Vergata | Cannuccia E.,European Theoretical Spectroscopy Facility | Marini A.,CNR Institute of Structure of Matter
Physical Review Letters | Year: 2011

The quantum zero-point motion of the carbon atoms is shown to induce strong effects on the optical and electronic properties of diamond and trans-polyacetylene, a conjugated polymer. By using an ab initio approach, we interpret the subgap states experimentally observed in diamond in terms of entangled electron-phonon states. These states also appear in trans-polyacetylene causing the formation of strong structures in the band structure that even call into question the accuracy of the band theory. This imposes a critical revision of the results obtained for carbon-based nanostructures by assuming the atoms frozen in their equilibrium positions. © 2011 American Physical Society. Source

Mencattini A.,University of Rome Tor Vergata | Salicone S.,Polytechnic of Milan
IEEE Transactions on Instrumentation and Measurement | Year: 2010

In the recent years, fuzzy variables (FVs) and random-fuzzy variables (RFVs) have been proposed to represent the measurement results with their associated uncertainty. However, up to now, the different authors do not yet agree in the mathematical way FVs should be composed together, so different approaches have been proposed. This paper compares these approaches to find their advantages and disadvantages and shows a new proposal that is supposed to hopefully overcome the disadvantages of the original approaches. © 2009 IEEE. Source

Luisetto I.,Third University of Rome | Tuti S.,Third University of Rome | Di Bartolomeo E.,University of Rome Tor Vergata
International Journal of Hydrogen Energy | Year: 2012

Co/CeO2 (Co 7.5 wt.%), Ni/CeO2 (Ni 7.5 wt.%) and Co-Ni/CeO2 (Co 3.75 wt.%, Ni 3.75 wt.%) catalysts were prepared by surfactant assisted co-precipitation method. Samples were characterized by X-Ray diffraction, BET surface areas measurements, temperature programmed reduction and tested for the dry reforming of methane CH4 + CO2 → 2CO + 2H2 in the temperature range 600-800 °C with a CH4:CO2:Ar 20:20:60 vol.% feed mixture and a total flow rate of 50 cm3 min-1 (GHSW = 30,000 mL g-1 h-1). The bimetallic Co-Ni/CeO2 catalyst showed higher CH4 conversion in comparison with monometallic systems in the whole temperature range, being 50% at 600 °C and 97% at 800 °C. H 2/CO selectivity decreased in the following order: Co-Ni/CeO 2 > Ni/CeO2 > Co/CeO2. Carbon deposition on spent catalysts was analyzed by thermal analysis (TG-DTA). After 20 h under stream at 750 °C, cobalt-containing catalysts, Co/CeO2 and Co-Ni/CeO2, showed a stable operation in presence of a deposited amorphous carbon of 6 wt.%, whereas Ni/CeO2 showed an 8% decrease of catalytic activity due to a massive presence of amorphous and graphitic carbon (25 wt.%). Copyright © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Borgognoni F.,ENEA | Borgognoni F.,University of Rome Tor Vergata | Tosti S.,ENEA
International Journal of Hydrogen Energy | Year: 2012

An experimental campaign has been carried out in order to assess the performance of a two-step membrane process in terms of hydrogen production by methane auto-thermal reforming. A reformer operating at high temperature (700 °C) has been coupled with a module consisting of an array of 19 Pd-Ag membranes (length 250 mm, diameter 10 mm and wall thickness 0.150 mm) operating at 300-400 °C. The hydrogen produced in the reformer has been selectively separated through the membrane tubes. The capability of the whole system to produce pure hydrogen has been investigated by varying the operating parameters: reformer temperature 580-700 °C, reaction pressure 100-500 kPa, water/methane feed molar ratio from 1.5/1 to 4.5/1 and methane feed flow rate in the range 4.47 × 10-4-1.11 × 10-3 mol s -1. Auto-thermal conditions have been studied by adding air in order to provide oxygen/methane feed molar ratio of 0.1/1, 0.33/1, 0.5/1. A maximum pure hydrogen flow rate of 1.65 × 10-3 mol s-1 has been collected in the membrane module shell with a reformer temperature of about 700 °C, membrane module temperature of 400 °C, reaction (lumen) pressure of 350 kPa, feed molar ratio methane/water/oxygen of 1/3/0.333 and methane feed flow rate of 1.11 × 10-3 mol s-1. Under these conditions the hydrogen yield measured has been 1.48. © 2011, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source

Curatolo P.,University of Rome Tor Vergata | Jozwiak S.,Childrens Memorial Health Institute
European Journal of Paediatric Neurology | Year: 2012

Tuberous sclerosis complex (TSC) is a leading genetic cause of epilepsy. TSC-associated epilepsy generally begins during the first year of life, and is associated with neurodevelopmental and cognitive problems. Management is challenging and seizures tend to persist in a large proportion of patients despite pharmacological and surgical treatment. This report summarizes the clinical recommendations for the management of TSC-associated epilepsy made by a panel of European experts in March 2012. Current treatment options and outstanding questions are outlined. © 2012 European Paediatric Neurology Society. Published by Elsevier Ltd. All rights reserved. Source

Piancastelli L.,University of Bologna | Frizziero L.,University of Bologna | Pezzuti E.,University of Rome Tor Vergata
ARPN Journal of Engineering and Applied Sciences | Year: 2014

Normally in diesel and gasoline engines, common rail systems are employed. The key factors for correct engine power management are pressure, precision and velocity. Digital computers and PID control systems characterize current systems. Recovery strategies are used when anomalies occur and engine performance is significantly reduced. So, restoring normal conditions needs technical assistance. For safety reasons this approach cannot be used in aeronautical, naval and energy-supply applications. In some cases it is necessary to utilize all the possible energy from the power unit causing significant life-reduction of the engine. In this case a progressive reduction strategy should be used and injection law should be reduced accordingly. For this purpose injection control based on fuzzy logic is more effective. In this case, traditional PID control systems are substituted by fuzzy logic control. A reference map is introduced in the Full Authority Digital Electronic Control; this map is interpreted by the fuzzy logic control system that adapts the injection law to the current engine situation. This method has been experimented on a common-rail test bed and results are compared with traditional "binary recovery strategy" FADEC. ©2006-2014 Asian Research Publishing Network (ARPN). Source

Lionetto A.,University of Rome Tor Vergata | Racioppi A.,Estonian National Institute of Chemical Physics and Biophysics
Nuclear Physics B | Year: 2010

We study the neutralino radiative decay into the lightest supersymmetric particle (LSP) in the framework of a minimal anomalous U (1)′ extension of the MSSM. It turns out that in a suitable decoupling limit the axino, which is present in the Stückelberg multiplet, is the LSP. We compute the branching ratio (BR) for the decay of a neutralino into an axino and a photon. We find that in a wide region of the parameter space, the BR is higher than 93% in contrast with the typical value (≲ 1 %) in the CMSSM. © 2010 Elsevier B.V. All rights reserved. Source

Micheletti A.,University of Rome Tor Vergata
Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2013

Tensegrity systems are prestressed frameworks composed of bars and cables. A particular elastic tensegrity system is examined. This system can be bistable in two fundamentally different ways, one depending on its geometric dimensions, and the other one depending on the initial deformation, or prestrain, of the elastic elements. A reduced-order semi-analytical model is derived, and its predictions are verified with a full-order numerical model. In particular, the critical geometry and prestrain at which the system switches from one regime to another are determined. This case study provides a benchmark and new insights on this class of structures. Copyright © The Royal Society 2013. Source

Barletta M.,University of Rome Tor Vergata | Gisario A.,University of Rome La Sapienza
Applied Surface Science | Year: 2011

The present investigation analyzes the deformation response of electrostatically sprayed epoxy-polyester powder coatings by 'in situ' micro-mechanical tests. The characterization of the performance of the coatings was carried out by micro-scale scratching, by varying the indenter type, the applied load and the sliding speed. The tests were carried out on polymeric coatings deposited on as-received, micro and macro-corrugated AISI 304 stainless steel substrates and 'rigidly adhered' to them. Further tests were performed on 'free-standing' coatings, that is, on the as-received metal substrates pre-coated with an intermediate layer of silicon-based heat curable release coating. Experimental data allow us to evaluate the influence of the contact conditions between substrate and indenter and the role of the loading conditions on the scratch and penetration resistance of the epoxy-polyester coatings. The different responses of the polymeric coatings when deposited on untreated or pre-treated substrates as well as on an intermediate layer of release coating, contribute to a better understanding of the intrinsic roles of the polymeric material and substrate as well as the influence of the interfacial adhesion between coating and substrate. © 2010 Elsevier B.V. Source

Semplici S.,University of Rome Tor Vergata
Medicine, Health Care and Philosophy | Year: 2013

The new dilemmas and responsibilities which arise in bioethics both because of the unprecedented pace of scientific development and of growing moral pluralism are more and more difficult to grapple with. At the 'global' level, the call for the universal nature at least of some fundamental moral values and principles is often being contended as a testament of arrogance, if not directly as a new kind of subtler imperialism. The human rights framework itself, which provided the basis for the most relevant international declarations and documents, is not exempt from the charge. However, the refusal of a top-down conception of the universal as a sort of product for exportation should not be confused with a relativistic landscape, where all the cows can be indifferently black or white. This contribution aims at outlining an approach, which reconciles universalism as enshrined in founding human rights declarations with respect for cultural diversity. In order to do so, two conceptual frameworks are discussed: the 'tool-kit' model and the morals/ethics difference. The example of the right to quality health care confirms the argument that striking a balance between cherishing pluralism and defending some fundamental rights and obligations does not amount to an assertion of moral imperialism. © 2013 Springer Science+Business Media Dordrecht. Source

Matthiae G.,University of Rome Tor Vergata
New Journal of Physics | Year: 2010

The Auger Observatory was designed to study high-energy cosmic rays by measuring the properties of the showers produced in the atmosphere. The instrument has taken data since January 2004 and was completed in 2008. First results on the energy spectrum of the primary cosmic rays for energies above 1018 eV with statistics larger than collected in previous works are presented and discussed. © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft. Source

Saladino R.,University of Tuscia | Crestini C.,University of Rome Tor Vergata | Pino S.,University of Rome La Sapienza | Costanzo G.,CNR Institute of Molecular Biology and Pathology | Di Mauro E.,University of Rome La Sapienza
Physics of Life Reviews | Year: 2012

The complexity of life boils down to the definition: "self-sustained chemical system capable of undergoing Darwinian evolution" (Joyce, 1994) [1]. The term "self-sustained" implies a set of chemical reactions capable of harnessing energy from the environment, using it to carry out programmed anabolic and catabolic functions. We briefly present our opinion on the general validity of this definition.Running anabolic and catabolic functions entails complex chemical information whose stability, reproducibility and evolution constitute the core of what is dubbed genetics.Life as-we-know-it is made of the intimate interaction of metabolism and genetics, both built around the chemistry of the most common elements of the Universe (hydrogen, oxygen, nitrogen, carbon). Other elements like phosphorus and sulphur play important but ancillary and potentially replaceable roles.The reproducible interaction of metabolic and genetic cycles results in the hypercycles of organization and de-organization of chemical information that we consider living entities. In order to approach the problem of the origin of life it is therefore reasonable to start from the assumption that both metabolism and genetics had a common origin, shared a common chemical frame, were embedded in physical-chemical conditions favourable for the onset of both.The most abundant three-atoms organic compound in interstellar environment is hydrogen cyanide HCN, the most abundant three-atoms inorganic compound is water H 2O. The combination of the two results in the formation of formamide H 2NCOH. We have explored the chemistry of formamide in conditions compatible with the synthesis and the stability of compounds of potential pre-genetic and pre-metabolic interest. We discuss evidence showing (i) that all the compounds necessary for the build-up of nucleic acids are easily obtained abiotically, (ii) that essentially all the steps leading to the spontaneous generation of RNA are abiotically possible, (iii) that the key compounds of extant metabolic cycles are obtained in the same chemical frame, often in the same test tube.How close are these observations to a plausible scenario for the origin of life?. © 2011 Elsevier B.V. Source

Tomellini M.,University of Rome Tor Vergata
Computational Materials Science | Year: 2011

The effect of the soft impingement mechanism on the kinetics of diffusion-controlled phase transitions of binary alloys is investigated. Soft impingement arises from the interference of the diffusional fields and implies a different morphology of the product phase when compared to that attained in the case of genuine impingement. Mean field rate equations for nucleus radius and supersaturation are coupled with the mass balance equation in terms of the geometrical parameter (time dependent) which defines the soft impingement process. The kinetics is studied as a function of the initial supersaturation and it is compared with that attained in the case of genuine impingement. Solutions of the kinetics are obtained in the model case of time dependent supersaturation which scales according to Ham's law and in the case of simultaneous nucleation. The phase transformation of immiscible alloys in one-dimensional system is also investigated. In this case and for point islands, the exact solution of the kinetics is obtained and allows one to gain an insight into the validity of the Kolmogorov-Johnson-Mehl-Avrami model and Avrami's exponent for one-dimensional growths. © 2011 Elsevier B.V. All rights reserved. Source

Guazzaroni M.,University of Tuscia | Crestini C.,University of Rome Tor Vergata | Saladino R.,University of Tuscia
Bioorganic and Medicinal Chemistry | Year: 2012

Agaricus bisporous tyrosinase was immobilized on commercial available epoxy-resin Eupergit®C250L and then coated by the Layer-by-Layer method (LbL). The two novel heterogeneous biocatalysts were characterized for their morphology, pH and storage stability, kinetic properties (K m, V max, V max/K m) and reusability. These biocatalysts were used for the efficient and selective synthesis of bioactive catechols under mild and environmental friendly experimental conditions. Ascorbic acid was added in the reaction medium to inhibit the formation of ortho-quinones, thus avoiding the known enzyme suicide inactivation process. Catechols were obtained mostly in quantitative yields and conversion of substrate. Tyrosinase immobilized on Eupergit®C250L and coated by the LbL method showed better catalytic activities, higher pH and storage stability, and reusability with respect to immobilized uncoated tyrosinase. Since chemical procedures to synthesize catechols are often expensive and with high environmental impact, the use of immobilized tyrosinase represents an efficient alternative for the preparation of this family of bioactive compounds. © 2011 Elsevier Ltd. All rights reserved. Source

Dymarsky A.,Institute for Advanced Study | Martucci L.,University of Rome Tor Vergata | Martucci L.,Ludwig Maximilians University of Munich
Journal of High Energy Physics | Year: 2011

We study how non-perturbative dynamics on D-branes affects the tendimensional geometry. We show that a gaugino condensate changes the complex and the symplectic structures of the original manifold by deforming the supersymmetry conditions. The cases of D5, D6 and D7-branes are discussed in detail. In the latter case we find the explicit form of the resulting back-reacted background at linear order in the gaugino condensate. © SISSA 2011. Source

Verrelli C.M.,University of Rome Tor Vergata | Damm G.,University of Evry Val dEssonne
International Journal of Control | Year: 2010

The robust transient stabilisation problem (with stability proof) of a synchronous generator in an uncertain power network with transfer conductances is rigorously formulated and solved. The generator angular speed and electrical power are required to be kept close, when mechanical and electrical perturbations occur, to the synchronous speed and mechanical input power, respectively, while the generator terminal voltage is to be regulated, when perturbations are removed, to its pre-fault reference constant value. A robust adaptive nonlinear feedback control algorithm is designed on the basis of a third-order model of the synchronous machine: only two system parameters (synchronous machine damping and inertia constants) along with upper and lower bounds on the remaining uncertain ones are supposed to be known. The conditions to be satisfied by the remote network dynamics for guaranteeing L2 and L∞ robustness and asymptotic relative speed and voltage regulation to zero are weaker than those required by the single machine-infinite bus approximation: dynamic interactions between the local deviations of the generator states from the corresponding equilibrium values and the remote generators states are allowed. © 2010 Taylor & Francis. Source

Casolino M.,University of Rome Tor Vergata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

In this work we discuss the Data Handling electronics of the JEM-EUSO experiment, devoted to the study of UHE Cosmic Rays from space. The detector is composed of about 6000 multianode photomultipliers for a total of ≃2×105 channels. A multi-layer parallel architecture has been devised to handle the data flow and select valid triggers, reducing it to a rate compatible with downlink constraints. Each processing level filters the event with increasingly complex algorithms using ASIC, FPGAs and DSPs in this order to reject spurious events and reduce the data rate. The main CPU monitors the general acquisition of the experiment, handles the slow control and the interfaces to the Space Station. In this work are discussed the hardware solutions adopted to cope with the various constraints posed by this space borne detector. © 2010 Elsevier B.V. All rights reserved. Source

Astolfi A.,Imperial College London | Astolfi A.,University of Rome Tor Vergata | Ortega R.,Supelec | Venkatraman A.,University of Groningen
Automatica | Year: 2010

The problem of velocity estimation for general, n degrees-of-freedom, mechanical systems, is of great practical and theoretical interest. For unconstrained systems many partial solutions have been reported in the literature. However, even in this case, the basic question of whether it is possible to design a globally convergent speed observer remains open. In this paper, an affirmative answer to the question is given for general mechanical systems with k non-holonomic constraints, by proving the existence of a 3 n - 2 k + 1-dimensional globally exponentially convergent speed observer. An observer for unconstrained mechanical systems is obtained as a particular case of this general result. Instrumental for the construction of the speed observer is the use of the Immersion and Invariance technique, in which the observer design problem is recast as a problem of rendering attractive and invariant a manifold defined in the extended state-space of the plant and the observer. © 2009 Elsevier Ltd. All rights reserved. Source

Araneo R.,University of Rome La Sapienza | Falconi C.,University of Rome Tor Vergata | Falconi C.,CNR Institute of Acoustics and Sensors Orso Mario Corbino
Nanotechnology | Year: 2013

Quasi-1D piezoelectric nanostructures may offer unprecedented sensitivity for transducing minuscule input mechanical forces into high output voltages due to both scaling laws and increased piezoelectric coefficients. However, until now both theoretical and experimental studies have suggested that, for a given mechanical force, lateral bending of piezoelectric nanowires results in lower output electric potentials than vertical compression. Here we demonstrate that this result only applies to nanostructures with a constant cross-section. Moreover, though it is commonly believed that the output electric potential of a strained piezo-semiconductive device can only be reduced by the presence of free charges, we show that the output piezopotential of laterally bent tapered nanostructures, with typical doping levels and very small input forces, can be even increased up to two times by free charges. Our analyses confirm that, though not optimal for piezoelectric energy harvesting, lateral bending of tapered nanostructures with typical doping levels can be ideal for transducing tiny input mechanical forces into high and accessible piezopotentials. Our results provide guidelines for designing high-performance piezo-nano-devices for energy harvesting, mechanical sensing, piezotronics, piezo-phototronics, and piezo-controlled chemical reactions, among others. © 2013 IOP Publishing Ltd. Source

Benzi R.,University of Rome Tor Vergata
Physica D: Nonlinear Phenomena | Year: 2010

In this paper we review some recent progress in understanding the phenomenon of drag reduction with polymers in wall bounded turbulence. © 2009 Elsevier B.V. All rights reserved. Source

Cattani G.,University of Rome Tor Vergata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2010

Resistive Plate Chambers (RPCs) provide the first-level muon trigger and the measurement of the coordinate in the non-bending direction in the barrel region of the muon spectrometer of the ATLAS experiment. Calibrating such a system means fine-tuning thousands of parameters (involving both front-end electronics and gap voltages) as well as constantly monitoring performance and environmental quantities such as gap efficiency, average cluster size, temperature, gas flow, gap currents, counting rates. In this paper the RPC calibration effort will be presented. An overview of the performance measurements done using cosmic rays will be also given. © 2009 Elsevier B.V. All rights reserved. Source

Coccia E.,University of Rome Tor Vergata
Acta Physica Polonica B | Year: 2010

Underground laboratories, shielded by the Earth's crust from the particles that rain down on the surface in the form of cosmic rays, provide the low radioactive background environment necessary to host key experiments in the field of particle and astroparticle physics, nuclear astrophysics and other disciplines that can profit of their characteristics and of their infrastructures. The cosmic silence condition existing in these laboratories allows the search for extremely rare phenomena and the exploration of the highest energy scales that cannot be reached with accelerators. I briefly describe all the facilities that are presently in operation around the world. Source

Coccia E.,University of Rome Tor Vergata
Journal of Physics: Conference Series | Year: 2010

Underground laboratories provide the low radioactive background environment necessary to host key experiments in the field of particle and astroparticle physics, nuclear astrophysics and other disciplines that can profit of their characteristics and of their infrastructures. The cosmic silence condition existing in these laboratories allows the search for extremely rare phenomena and the exploration of the highest energy scales that cannot be reached with accelerators. I briefly describe all the facilities that are presently in operation around the world. © 2010 IOP Publishing Ltd. Source

Rufini A.,University of Leicester | Tucci P.,University of Leicester | Tucci P.,University of Calabria | Celardo I.,University of Leicester | And 2 more authors.
Oncogene | Year: 2013

p53 functions as a transcription factor involved in cell-cycle control, DNA repair, apoptosis and cellular stress responses. However, besides inducing cell growth arrest and apoptosis, p53 activation also modulates cellular senescence and organismal aging. Senescence is an irreversible cell-cycle arrest that has a crucial role both in aging and as a robust physiological antitumor response, which counteracts oncogenic insults. Therefore, via the regulation of senescence, p53 contributes to tumor growth suppression, in a manner strictly dependent by its expression and cellular context. In this review, we focus on the recent advances on the contribution of p53 to cellular senescence and its implication for cancer therapy, and we will discuss p53's impact on animal lifespan. Moreover, we describe p53-mediated regulation of several physiological pathways that could mediate its role in both senescence and aging. © 2013 Macmillan Publishers Limited. Source

Sbragaglia M.,University of Rome Tor Vergata | Sugiyama K.,University of Tokyo
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010

We analyze a volumetric formulation of lattice Boltzmann for compressible thermal fluid flows. The velocity set is chosen with the desired accuracy, based on the Gauss-Hermite quadrature procedure, and tested against controlled problems in bounded and unbounded fluids. The method allows the simulation of thermohydrodyamical problems without the need to preserve the exact space-filling nature of the velocity set, but still ensuring the exact conservation laws for density, momentum, and energy. Issues related to boundary condition problems and improvements based on grid refinement are also investigated. © 2010 The American Physical Society. Source

Conti R.,International School for Advanced Studies | Madabhushi G.S.P.,University of Cambridge | Viggiani G.M.B.,University of Rome Tor Vergata
Geotechnique | Year: 2012

This paper describes an experimental investigation of the behaviour of embedded retaining walls under seismic actions. Nine centrifuge tests were carried out on reduced-scale models of pairs of retaining walls in dry sand, either cantilevered or with one level of props near the top. The experimental data indicate that, for maximum accelerations that are smaller than the critical limit equilibrium value, the retaining walls experience significant permanent displacements under increasing structural loads, whereas for larger accelerations the walls rotate under constant internal forces. The critical acceleration at which the walls start to rotate increases with increasing maximum acceleration. No significant displacements are measured if the current earthquake is less severe than earthquakes previously experienced by the wall. The increase of critical acceleration is explained in terms of redistribution of earth pressures and progressive mobilisation of the passive strength in front of the wall. The experimental data for cantilevered retaining walls indicate that the permanent displacements of the wall can be reasonably predicted adopting a Newmark-type calculation with a critical acceleration that is a fraction of the limit equilibrium value. Source

Squitti R.,AFaR Fatebenefratelli Hospital | Squitti R.,Biomedical University of Rome | Polimanti R.,University of Rome Tor Vergata
Journal of Alzheimer's Disease | Year: 2012

Testi M.,University of Rome Tor Vergata
Tissue antigens | Year: 2013

The novel allele HLA-DQB1*04:09 differs from DQB1*04:02:01 by three nonsynonymous nucleotide substitutions in exon 2. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source

Gravante G.,Pilgrim Hospital | Venditti D.,University of Rome Tor Vergata
Surgical Laparoscopy, Endoscopy and Percutaneous Techniques | Year: 2013

Introduction:: Low-cost box models (BMs) are a valuable tool alternative to virtual-reality simulators. We aim to provide surgical trainees with a description of most common BMs and to present their validity to achieve basic and advanced laparoscopic skills. Materials and Methods:: A literature search was undertaken for all studies focusing on BMs, excluded were those presenting data on virtual-reality simulators only. Databases were screened up to December 2011. Results:: Numerous studies focused on various BMs to improve generic tasks (ie, instrument navigation, coordination, and cutting). Only fewer articles described models specific for peculiar operations. All studies showed a significant improvement of basic laparoscopic skills after training with BMs. Furthermore, their low costs make them easily available to most surgical trainees. Conclusions:: BMs should be developed by all surgical trainees during their training. Fields for future improvement regard endoscopy and complex laparoscopic operations for which ad hoc BMs are not available. © 2013 by Lippincott Williams and Wilkins. Source

Billi D.,University of Rome Tor Vergata
Origins of Life and Evolution of Biospheres | Year: 2012

Two GFP-based plasmids, namely pTTQ18-GFP-pDU1mini and pDUCA7-GFP, of about 7 kbp and 15 kbp respectively, able to replicate in Chroococcidiopsis sp. CCMEE 029 and CCMEE 123, were developed. Both plasmids were maintained in Chroococcidiopsis cells after 18 months of dry storage as demonstrated by colony PCR, plasmid restriction analysis, GFP imaging and colony-forming ability under selection of dried transformants; thus suggesting that strategies employed by this cyanobacterium to stabilize dried chromosomal DNA, must have protected plasmid DNA. The suitability of pDU1mini-plasmid for GFP tagging in Chroococcidiopsis was investigated by using the RecA homolog of Synechocystis sp. PCC 6803. After 2 months of dry storage, the presence of dried cells with a GFP-RecASyn distribution resembling that of hydrated cells, supported its capability of preventing desiccation-induced genome damage, whereas the rewetted cells with filamentous GFP-RecASyn structures revealed sub-lethal DNA damage. The long-term stability of plasmid DNA in dried Chroococcidiopsis has implication for space research, for example when investigating the recovery of dried cells after Martian and space simulations or when developing life support systems based on phototrophs with genetically enhanced stress tolerance and stored in the dry state for prolonged periods. © 2012 Springer Science+Business Media B.V. Source

Cazzola M.,University of Rome Tor Vergata | Anapurapu S.,Sprim Advanced Life science | Page C.P.,Kings College London
Pulmonary Pharmacology and Therapeutics | Year: 2012

Background: Respiratory tract infections are common and remain a major source of morbidity, mortality and economic cost worldwide, despite advances in modern medicine. One treatment approach is to non-specifically increase the immune response or augment innate defense mechanisms through the use of bacterial lysates. Polyvalent Mechanical Bacterial Lysate (PMBL) is a bacterial lysate made from a wide range of pathogenic bacteria, including all of the most commonly occurring pathogens of the upper and lower respiratory tract obtained by mechanical lysis. Aim: To test the available evidence that PMBL is able to prevent respiratory tract infections. Methods: A number of studies investigating randomized comparisons of PMBL (active) with placebo or no treatment (control) were selected for analysis. The primary outcome measure was the prevention of exacerbations or acute respiratory tract infection. The results were expressed as relative risk (RR) and the number of patients needed to treat for one to benefit (NNTB). Results: Data from 2557 patients from 15 randomized clinical trials (RCTs) was investigated. PMBL induced a significant reduction of infections vs placebo (RR-0.513; 95% CI;-0.722--0.303; p=0.00). The NNTB was 1.15. The RR was always in favor of PMBL (in recurrent respiratory infections other than COPD, chronic bronchitis and tuberculosis, RR-0.502; 95% CI-0.824--0.181; in children RR-2.204; 95% CI-3.260--1.147; in COPD or chronic bronchitis, RR-0.404; 95% CI-0.864-0.057; in tuberculosis, RR-0.502; 95% CI-0.890--0.114). Conclusions: The results of the present meta-analysis suggest that PBML is effective in both in children and in adults in preventing respiratory tract infections. Our current meta-analysis shows that there is a trend with PBML toward clinically significant results in patients with COPD but it did not quite achieve statistical significance due to the small number of COPD studies. © 2011 Elsevier Ltd. Source

Lechner G.,University of Leipzig | Longo R.,University of Rome Tor Vergata
Communications in Mathematical Physics | Year: 2015

Starting from a real standard subspace of a Hilbert space and a representation of the translation group with natural properties, we construct and analyze for each endomorphism of this pair a local, translationally covariant net of standard subspaces, on the lightray and on two-dimensional Minkowski space. These nets share many features with low-dimensional quantum field theory, described by corresponding nets of von Neumann algebras.Generalizing a result of Longo and Witten to two dimensions and massive multiplicity free representations, we characterize these endomorphisms in terms of specific analytic functions. Such a characterization then allows us to analyze the corresponding nets of standard spaces, and in particular to compute their minimal localization length. The analogies and differences to the von Neumann algebraic situation are discussed. © 2014, Springer-Verlag Berlin Heidelberg. Source

Breccia M.,University of Rome La Sapienza | Lo-Coco F.,University of Rome Tor Vergata
Expert Opinion on Biological Therapy | Year: 2011

Introduction: Acute promyelocytic leukemia (APL) is characterized by peculiar biological features and high sensitivity to therapeutic agents such as anthracyclines, all-trans retinoic acid (ATRA) and arsenic trioxide (ATO). Because cure rates of up to 80 90% have been reported using various combinations of the above agents, future strategies will probably aim at reducing therapy-related toxicity while maintaining therapeutic efficacy. Gemtuzumab ozogamicin (GO) is a calicheamicin-conjugated mAb directed against CD33, a surface antigen highly expressed on APL blasts. GO has been shown to be effective in this disease and better tolerated than conventional chemotherapy. Areas covered: This review looks at the mechanism of action, pathways associated with resistance and toxicity profile of GO. Reported experience on the use of GO for relapsed or newly diagnosed APL is also discussed along with evidence on its efficacy and relative tolerability in APL management. In addition to its activity in advanced disease, data suggest that GO in various combinations may replace chemotherapy in APL front-line therapy. This should apply in particular to some subsets such as elderly patients or those unfit to receive conventional chemotherapy. Expert opinion: GO has proven effective and relatively safe as a single agent in advanced APL. In combinations with ATRA and/or ATO, GO may substitute for conventional chemotherapy of APL, particularly in unfit patients. © 2011 Informa UK, Ltd. Source

Alteri C.,University of Rome Tor Vergata
The Journal of antimicrobial chemotherapy | Year: 2013

This study evaluates the impact of specific HIV-1 protease-compensatory mutations (wild-type amino acids in non-B subtypes) on virological response to a first-line lopinavir/ritonavir-containing regimen in an HIV-1 subtype B-infected population. The prevalence of protease-compensatory mutations from 1997 to 2011 was calculated in 3063 drug-naive HIV-1 B-infected patients. The role of these mutations on virological outcome is estimated in a subgroup of 201 patients starting their first lopinavir/ritonavir-containing regimen by covariation and docking analyses. The number of HIV-1 B-infected patients with at least one protease-compensatory mutation increased over time (from 86.4% prior to 2001 to 92.6% after 2009, P = 0.02). Analysing 201 patients starting first-line lopinavir/ritonavir, the median time to virological failure was shorter in patients with at least one protease-compensatory mutation than in patients with no protease-compensatory mutations. By covariation and docking analyses, specific mutations were found to affect lopinavir affinity for HIV-1 protease and to impact virological failure. Specifically, the L10V + I13V + L63P + I93L cluster, related to fast virological failure, correlated with a decreased drug affinity for the enzyme in comparison with wild-type (ΔGmut = -30.0 kcal/mol versus ΔGwt = -42.3 kcal/mol). Our study shows an increased prevalence of specific protease-compensatory mutations in an HIV-1 B-infected population and confirms that their copresence can affect the virological outcome in patients starting a lopinavir/ritonavir-containing regimen. Source

Pieraccioli M.,University of Rome Tor Vergata
Oncogene | Year: 2015

ZNF281 is a zinc-finger factor involved in the control of cellular stemness and epithelial–mesenchymal transition (EMT). Here, we report that ZNF281 expression increased after genotoxic stress caused by DNA-damaging drugs. Comet assays demonstrated that DNA repair was delayed in cells silenced for the expression of ZNF281 and treated with etoposide. Furthermore, the expression of 10 DNA damage response genes was downregulated in cells treated with etoposide and silenced for ZNF281. In line with this finding, XRCC2 and XRCC4, two genes that take part in homologous recombination and non-homologous end joining, respectively, were transcriptionally activated by ZNF281 through a DNA-binding-dependent mechanism, as demonstrated by luciferase assays and Chromatin crosslinking ImmunoPrecipitation experiments. c-Myc, which also binds to the promoters of XRCC2 and XRCC4, was unable to promote their transcription or to modify ZNF281 activity. Of interest, bioinformatic analysis of 1971 breast cancer patients disclosed a significant correlation between the expression of ZNF281 and that of XRCC2. In summary, our data highlight, for the first time, the involvement of ZNF281 in the cellular response to genotoxic stress through the control exercised on the expression of genes that act in different repair mechanisms.Oncogene advance online publication, 24 August 2015; doi:10.1038/onc.2015.320. © 2015 Macmillan Publishers Limited Source

Talj R.,French National Center for Scientific Research | Ortega R.,University Paris - Sud | Astolfi A.,Imperial College London | Astolfi A.,University of Rome Tor Vergata
Automatica | Year: 2011

Fuel cells are electrochemical devices that convert the chemical energy of a gaseous fuel directly into electricity. They are widely regarded as potential future stationary and mobile power sources. The response of a fuel cell system depends on the air and hydrogen feed, flow and pressure regulation, and heat and water management. In this paper, the study is concentrated on the control of the air subsystem that feeds the fuel cell cathode with oxygenwhose dynamics is described with a widely accepted nonlinear model. Due to the complexity of this model, the model-based controllers that have been proposed for this application are designed using its linear approximation at a given equilibrium point, which might lead to conservative stability margin estimates for the usually wide operating ranges of the system. On the other hand, practitioners propose the use of simple proportional or proportionalintegral controllers around the compressor flow, which ensures good performance in most applications. In this paper we provide the theoretical justification to this scheme, proving that this output variable has the remarkable property that the linearization (around any admissible equilibrium) of the inputoutput map is strictly passive. Hence, the controllers used in applications yield (locally) asymptotically stable loopsfor any desired equilibrium point and all values of the controller gains. Ensuring stability for all tuning gains overcomes the inherent conservativeness of linearized dynamics analysis, and assures the designer on the current use of robust, high performance loops. Instrumental to prove the passivity property is the exploitation of some monotonicity characteristics of the system that stem from physical laws. © 2011 Elsevier Ltd. All rights reserved. Source

Chen W.-M.,National Taiwan University | Huang Y.-T.,National Taiwan University | Huang Y.-T.,Institute for Advanced Study | Wen C.,University of Rome Tor Vergata
Journal of High Energy Physics | Year: 2015

Abstract: It is known that for (Formula presented.) supergravity, the double-soft-scalar limit of a n-point amplitude is given by a sum of local SU(8) rotations acting on a (n−2)-point amplitude. For (Formula presented.) supergravity theories, complication arises due to the presence of a U(1) in the (Formula presented.) isotropy group, which introduces a soft-graviton singularity that obscures the action of the duality symmetry. In this paper, we introduce an anti-symmetrised extraction procedure that exposes the full duality group. We illustrate this procedure for tree-level amplitudes in 4 (Formula presented.) supergravity in four dimensions, as well as (Formula presented.) supergravity in three dimensions. In three dimensions, as all bosonic degrees of freedom transform under the E8 duality group, supersymmetry ensures that the amplitude vanishes in the single-soft limit of all particle species, in contrast to its higher dimensional siblings. Using recursive formulas and generalized unitarity cuts in three dimensions, we demonstrate the action of the duality group for any tree-level and one-loop amplitudes. Finally we discuss the implications of the duality symmetry on possible counter terms for this theory. As a preliminary application, we show that the vanishing of single-soft limits of arbitrary component fields in three-dimensional supergravity rules out the direct dimensional reduction of D8R4 as a valid counter term. © 2015, The Author(s). Source

Nesic D.,University of Melbourne | Teel A.R.,University of California at Santa Barbara | Zaccarian L.,University of Rome Tor Vergata
IEEE Transactions on Automatic Control | Year: 2011

We consider set-point regulation and L2 robust stability properties of a class of reset control systems consisting of a minimum-phase relative degree-one linear SISO plant controlled by a novel first-order reset element (FORE). These results rely on necessary and sufficient conditions for exponential and L2 finite gain stability of a class of planar reset systems consisting of a scalar linear plant controlled by the novel FORE. We show that the L2 gain of the planar reset system decreases to zero as the pole and/or the gain of the FORE are increased to infinity. A number of stability results, including Lyapunov conditions for Lp and exponential stability, for a larger class of reset and hybrid systems are presented and used to prove our main results. © 2011 IEEE. Source

Cazzola M.,University of Rome Tor Vergata | Matera M.G.,The Second University of Naples
Pulmonary Pharmacology and Therapeutics | Year: 2012

Amelio I.,Medical Research Council Toxicology Unit | Inoue S.,Ontario Cancer Institute | Markert E.K.,Institute for Advanced Study | Levine A.J.,Institute for Advanced Study | And 4 more authors.
Proceedings of the National Academy of Sciences of the United States of America | Year: 2015

Tumor hypoxia and hypoxia-inducible factor 1 (HIF-1) activation are associated with cancer progression. Here, we demonstrate that the transcription factor TAp73 opposes HIF-1 activity through a nontranscriptional mechanism, thus affecting tumor angiogenesis. TAp73-deficient mice have an increased incidence of spontaneous and chemically induced tumors that also display enhanced vascularization. Mechanistically, TAp73 interacts with the regulatory subunit (α) of HIF-1 and recruits mouse double minute 2 homolog into the protein complex, thus promoting HIF-1α polyubiquitination and consequent proteasomal degradation in an oxygen-independent manner. In human lung cancer datasets, TAp73 strongly predicts good patient prognosis, and its expression is associated with low HIF-1 activation and angiogenesis. Our findings, supported by in vivo and clinical evidence, demonstrate a mechanism for oxygen-independent HIF-1 regulation, which has important implications for individualizing therapies in patients with cancer. © 2014, National Academy of Sciences. All rights reserved. Source

Gentileschi P.,University of Rome Tor Vergata
Gastroenterology Research and Practice | Year: 2012

Introduction. Laparoscopic sleeve gastrectomy (LSG) represents a valid option for morbid obesity, either as a primary or as a staged procedure. The aim of this paper is to report the experience of a single surgeon with LSG as a standalone operation for morbid obesity. Methods. From April 2006 to April 2011, 200 patients underwent LSG for morbid obesity. Each patient record was registered and prospectively collected. In July 2011, a retrospective analysis was conducted. Results. Patients were 128 females and 72 males with a median age of 40.0 years. Median pre-operative BMI was 49.4kg 2. Median follow-up was 27.2 months. Median post-operative BMI was 30.4kg 2. Median excess weight loss (EWL) was 63.6. Median post-operative hospital stay was 4.0 days in the first 84 cases and 3.0 days in the last 116 cases. Six major post-operative complications occurred (3): two gastric stump leaks (1), three major bleedings (1.5) and 1 (0.5) bowel obstruction. One case of mortality was registered (0.5). To date only 4 patients are still in the range of morbid obesity (BMI 35kg 2). Conclusions. Laparoscopic sleeve gastrectomy is a formidable operation in the short-term period. Median EWL in this series was 63.6 at 27.2 months follow-up. Copyright © 2012 Paolo Gentileschi. Source

Spagnolo G.,University of Rome Tor Vergata
International Journal of Industrial Organization | Year: 2012

Based on my recent work with several co-authors this paper explores the relationship between discretion, reputation, competition and entry in procurement markets. I focus especially on public procurement, which is highly regulated for accountability and trade reasons. In Europe regulation constrains the use of past performance information to select contractors while in the US its use is encouraged. I present some novel evidence on the benefits of allowing buyers to use reputational indicators based on past performance and discuss the complementary roles of discretion and restricted competition in reinforcing relational/reputational forces, both in theory and in a new empirical study on the effects restricted rather than open auctions. I conclude reporting preliminary results form a laboratory experiment showing that reputational mechanisms can be designed to stimulate rather than hindering new entry. © 2012 Elsevier B.V. All rights reserved. Source

Cantone L.,University of Rome Tor Vergata
Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit | Year: 2011

The increasing demand of long and interoperable freight trains requires suitable numerical simulators of train longitudinal dynamics. Focusing attention on the European railway freight transport, such simulators need to properly model the typical Union Internationale des Chemins de Fer (UIC) pneumatic brake, even for more than one active locomotive placed along the train. A pneumatic model, previously developed, has been integrated in a software for longitudinal train dynamics (TrainDy). This software has been successfully subjected to an international process of validation and certification, undertaken by an ad hoc expert group on behalf of UIC. By using TrainDy, UIC plans to update the actual limits of the UIC leaflet 421. Moreover, UIC has established a consortium dedicated to further improve the code. This article outlines the main features of the simulator along with the most significant results of its validation process. Source

Squitti R.,Fatebenefratelli Foundation for Health Research and Education | Squitti R.,Laboratorio Of Neurodegenerazione | Siotto M.,Don Carlo Gnocchi Foundation ONLUS | Polimanti R.,University of Rome Tor Vergata
Neurobiology of Aging | Year: 2014

Copper is an essential element, and either a copper deficiency or excess can be life threatening. Recent studies have indicated that alteration of copper metabolism is one of the pathogenetic mechanisms of Alzheimer's disease (AD). In light of these findings, many researchers have proposed preventive strategies to reduce AD risk. Because the general population comes in contact with copper mainly through dietary intake, that is, food 75% and drinking water 25%, a low-copper diet can reduce the risk of AD in individuals with an altered copper metabolism. We suggest that a diet-gene interplay is at the basis of the "copper phenotype" of sporadic AD. Herein, we describe the pathways regulating copper homeostasis, the adverse sequelae related to its derangements, the pathogenic mechanism of the AD copper phenotype, indications for a low-copper diet, and future perspectives to improve this preventive strategy. © 2014 Elsevier Inc. Source

Sisto R.,INAIL Ex ISPESL | Sanjust F.,INAIL Ex ISPESL | Moleti A.,University of Rome Tor Vergata
Journal of the Acoustical Society of America | Year: 2013

The input/output functions of the different-latency components of human transient-evoked and stimulus-frequency otoacoustic emissions are analyzed, with the goal of relating them to the underlying nonlinear dynamical properties of the basilar membrane response. Several cochlear models predict a cubic nonlinearity that would yield a correspondent compressive response. The otoacoustic response comes from different generation mechanisms, each characterized by a particular relation between local basilar membrane displacement and otoacoustic level. For the same mechanism (e.g., reflection from cochlear roughness), different generation places would imply differently compressive regimes of the local basilar membrane dynamics. Therefore, this kind of study requires disentangling these contributions, using suitable data acquisition and time-frequency analysis techniques. Fortunately, different generation mechanisms/places also imply different phase-gradient delays, knowledge of which can be used to perform this task. In this study, the different-latency otoacoustic components systematically show differently compressive response, consistent with two simple hypotheses: (1) all emissions come from the reflection mechanism and (2) the basilar membrane response is strongly compressive in the resonance region and closer to linear in more basal regions. It is not clear if such a compressive behavior also extends to arbitrarily low stimulus levels. © 2013 Acoustical Society of America. Source

Abundo M.,University of Rome Tor Vergata
Physica A: Statistical Mechanics and its Applications | Year: 2016

By using the law of the excursions of Brownian motion with drift, we find the distribution of the nth passage time of Brownian motion through a straight line S(t)=a+bt. In the special case when b=0, we extend the result to a space-time transformation of Brownian motion. © 2016 Elsevier B.V. All rights reserved. Source

Chakrabartty J.P.,INRS - Institute National de la Recherche Scientifique | Nechache R.,University of Rome Tor Vergata | Harnagea C.,INRS - Institute National de la Recherche Scientifique | Rosei F.,INRS - Institute National de la Recherche Scientifique | Rosei F.,McGill University
Optics Express | Year: 2014

We report an external solar power conversion efficiency of ∼0.1% in Bi-Mn-O thin films grown onto (111) oriented Niobium doped SrTiO3 (STO) single crystal substrate by pulse laser deposition (PLD). The films contain BiMnO3 (BMO) and Mn3O4 (MO) phases, which both grow epitaxially. The growth conditions were tailored to obtain films with different Bi/Mn ratios. The films were subsequently illuminated under a sun simulator (AM 1.5 G). We find that the Bi/Mn ratio in the film affects the magnitude of the photo induced voltage and photocurrent and therefore the photovoltaic conversion efficiency. Specifically, a higher Bi/Mn ratio (towards unity) in the film increases the power conversion efficiency. This effect is described in terms of a more favorable energy band alignment of the film/substrate hetero-structure junction, which controls photo carrier separation. © 2013 Optical Society of America. Source

Loreni F.,University of Rome Tor Vergata | Mancino M.,San Raffaele Scientific Institute | Biffo S.,San Raffaele Scientific Institute
Oncogene | Year: 2014

Gene expression is shaped by translational control. The modalities and the extent by which translation factors modify gene expression have revealed therapeutic scenarios. For instance, eukaryotic initiation factor (eIF)4E activity is controlled by the signaling cascade of growth factors, and drives tumorigenesis by favoring the translation of specific mRNAs. Highly specific drugs target the activity of eIF4E. Indeed, the antitumor action of mTOR complex 1 (mTORc1) blockers like rapamycin relies on their capability to inhibit eIF4E assembly into functional eIF4F complexes. eIF4E biology, from its inception to recent pharmacological targeting, is proof-of-principle that translational control is druggable. The case for eIF4E is not isolated. The translational machinery is involved in the biology of cancer through many other mechanisms. First, untranslated sequences on mRNAs as well as noncoding RNAs regulate the translational efficiency of mRNAs that are central for tumor progression. Second, other initiation factors like eIF6 show a tumorigenic potential by acting downstream of oncogenic pathways. Third, genetic alterations in components of the translational apparatus underlie an entire class of inherited syndromes known as 'ribosomopathies' that are associated with increased cancer risk. Taken together, data suggest that in spite of their evolutionary conservation and ubiquitous nature, variations in the activity and levels of ribosomal proteins and translation factors generate highly specific effects. Beside, as the structures and biochemical activities of several noncoding RNAs and initiation factors are known, these factors may be amenable to rational pharmacological targeting. The future is to design highly specific drugs targeting the translational apparatus. © 2014 Macmillan Publishers Limited. All rights reserved. Source

Perno C.F.,University of Rome Tor Vergata
Annali dell'Istituto Superiore di Sanita | Year: 2011

The therapy of HIV infection has been dramatically improved over the years, and allowed the achievement of unexpected results. The availability of many drugs, and the knowledge of HIV related pathogenesis, helped in selecting highly effective antiviral therapies, yet today a major challenge stands, that is the selection of the best regimen(s) in clinical practice. In this frame, evidencebased medicine remains a cornerstone of modern medicine, but its structure needs to be adapted to the new challenges, made by an excess of information (not always fully reliable), by highly sophisticated statistical systems that may overlook the clinical practice despite their ability to define the statistical significance, and the limited number of independent controlled studies. The revision of the criteria of evidence-based medicine, and their adaptation to the new tools available, may allow a better contribution to the definition of the best therapy for each single patient. Source

Santo L.,University of Rome Tor Vergata
Progress in Aerospace Sciences | Year: 2016

Recent advances in shape memory polymer (SMP) foam research are reviewed. The SMPs belong to a new class of smart polymers which can have interesting applications in microelectromechanical systems, actuators and biomedical devices. They can respond to specific external stimulus changing their configuration and then remember the original shape. In the form of foams, the shape memory behaviour can be enhanced because they generally have higher compressibility. Considering also the low weight, and recovery force, the SMP foams are expected to have great potential applications primarily in aerospace. This review highlights the recent progress in characterization, evaluation, and proposed applications of SMP foams mainly for aerospace applications. © 2016 Elsevier Ltd. Source

Perilli L.,University of Rome Tor Vergata
Early Science and Medicine | Year: 2012

The Aldine edition of Galen, awaited for more than 25 years, was perhaps the most risky enterprise in the whole history of the publishing house, and it almost brought Aldus' heirs to bankruptcy. Although the editors were among the most renowned specialists of the time, the edition was harshly criticized by one former friend and collaborator of Aldus, Desiderius Erasmus of Rotterdam. Why? Was the edition so bad, were the manuscripts on which the edition was based responsible for its quality? Or were there other reasons for Erasmus' complaint? This paper tries to give some hints in order to answer such questions, arguing that the role of Erasmus in the assessment of the value of the edition should take us into Aldus' house in the period of the late fifteenth and early sixteenth century, and into the political and religious debate of the time. © 2012 BRILL. Source

Picazio S.,Non invasive Brain Stimulation Unit | Koch G.,Non invasive Brain Stimulation Unit | Koch G.,University of Rome Tor Vergata
Cerebellum | Year: 2015

Motor inhibition is an essential skill for fully adapted behavior requiring motor control and higher-order functions of motor cognition. A wide set of cortical and subcortical areas, including the right inferior frontal gyrus, the pre-supplementary motor area, and the subthalamic nucleus in the basal ganglia, contribute to convey the inhibitory command to the motor cortex. In the present review, we discuss how recent evidence supports the idea that the cerebellum may also have a relevant contribution in certain aspects of motor inhibition. This evidence were provided by behavioral data collected in patients with cerebellar lesions, functional magnetic resonance (fMRI) investigations conducted in clinical samples and in healthy participants, and by transcranial magnetic stimulation (TMS) techniques used to non-invasively test cerebello-motor functional connectivity. The application of these methods, combined with the execution of inhibitory tasks, could provide new evidence for a causal role of the effective cerebello-cortical connectivity in motor inhibition. Understanding the neurophysiological mechanisms that mediate motor inhibition through the cerebellum could be essential to design new rehabilitative protocols for treating several neurological and psychiatric disorders characterized by disinhibited behavior such as addiction, schizophrenia, attention deficit hyperactivity disorder (ADHD) and Parkinson’s disease. © 2014, Springer Science+Business Media New York. Source

Tomassetti G.,University of Rome Tor Vergata
Archive of Applied Mechanics | Year: 2011

We propose a new derivation of the evolution equation of a sharp, coherent interface in a two-phase body having elongated shape, a body which we regard as a one-dimensional micropolar continuum. To this aim, we introduce a system of forces acting at the interface, and we apply the method of virtual powers to derive a balance law involving these forces. By exploiting the dissipation inequality, we manage to write this balance law in terms of a scalar field whose form is reminiscent of a well-known expression for the configurational stress in three dimensional micropolar continua. © 2010 Springer-Verlag. Source

Pandolfi L.,University of Rome Tor Vergata
Bollettino della Societa Paleontologica Italiana | Year: 2013

Three rhinoceros species have been identified at Ponte Milvio: Stephanorhinus hundsheimensis (Toula, 1902), Stephanorhinus hemitoechus (Falconer, 1859) and Stephanorhinus kirchbergensis (Jäger, 1839). Remains ascribed to S. hundsheimensis were collected in gravels and sands deposits. They show morphological and morphometric affinities with the small-sized populations of the latest Early Pleistocene from Vallonnet. The occurrence of these small-sized specimens suggests the presence of a faunal assemblage chronologically related with the Early-Middle Pleistocene transition. The remains of S. hemitoechus and S. kirchbergensis were collected in volcanoclastic deposits. The specimens ascribed to S. hemitoechus show morphometric characters close to the small-sized specimens of the latest Middle Pleistocene. Moreover, S. kirchbergensis seems to be common in Italy during the late Middle Pleistocene and it has never been collected with certainty from Late Pleistocene sites. The co-occurrence of S. kirchbergensis and the small-sized S. hemitoechus suggests the presence of a faunal assemblage chronologically referable to a time span between MIS10 and MIS8. © 2013, Mucchi Editori s.r.l. All rights reserved. Source

Giuliani A.,Third University of Rome | Mastropietro V.,University of Rome Tor Vergata | Porta M.,University of Rome La Sapienza
Physical Review B - Condensed Matter and Materials Physics | Year: 2010

The effects of the electromagnetic (em) electron-electron interactions in half-filled graphene are investigated in terms of a lattice gauge theory model. By using exact renormalization group methods and lattice Ward identities, we show that the em interactions amplify the responses to the excitonic pairings associated to a Kekulé distortion and to a charge-density wave. The effect of the electronic repulsion on the Peierls-Kekulé instability, usually neglected, is evaluated by deriving an exact non BCS gap equation, from which we find evidence that strong em interactions among electrons facilitate the spontaneous distortion of the lattice and the opening of a gap. © 2010 The American Physical Society. Source

De Sanctis M.,University of Rome Tor Vergata
Wireless Personal Communications | Year: 2016

The KNOWLEDGE-CARE vision is to enable new e-health services that are personalized, preventive, predictive, pre-emptive, participatory, pervasive and precise. This vision aims to make a move from reactive medicine to predictive medicine, developing dynamic and responsive models through knowledge extraction and using such models for personalized clinical healthcare. The proposed healthcare ecosystem can learn over time and can adapt to the variation seen in the actual real-world population. © 2016, Springer Science+Business Media New York. Source

Chan A.,Ruhr University Bochum | Lo-Coco F.,University of Rome Tor Vergata
Neurology | Year: 2013

Despite the long-standing and extensive use of mitoxantrone (MTZ) for the treatment of aggressive forms of multiple sclerosis (MS), especially in Europe, its benefit-risk profile remains controversial. In particular, the risk of developing therapy-related acute leukemia (TRAL) and cardiotoxicity have led to treatment restrictions for MTZ; however, the precise risk for these severe complications is still unclear. Here we review current data on TRAL incidence, research strategies aimed at individual risk stratification, and provide recommendations for hematologic monitoring. A recent meta-analysis indicates a TRAL risk of approximately 0. 81%, more than 10-fold higher than in previously reported meta-analyses (0. 07%). There also appear to be considerable differences among countries, with recent TRAL risk estimates from Italy as high as 0. 93%, compared to the 0. 25%-0. 41% risk reported from Germany and France. Whereas methodologic differences may partly account for some of these differences, high regional variability may point to exogenous factors such as heterogeneous treatment protocols and cotreatments. In addition, genetic risk factors (MTZ metabolism, DNA repair) might contribute to the individual risk profile. The case of potentially curable MTZ-induced secondary leukemia highlights the need for close hematologic monitoring during and after therapy. Intensive collaboration between neurologists and hematologists will likely provide benefits both for research efforts aimed at unraveling TRAL pathogenesis and for clinical practice with improved identification and monitoring of patients at higher risk of MTZ-induced TRAL. This is of particular importance, since treatment alternatives, especially in secondary progressive MS, are sparse. © 2013 American Academy of Neurology. Source

Esposito A.,Columbia University | Guerrieri A.L.,University of Rome Tor Vergata | Pilloni A.,University of Rome La Sapienza
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2015

The nature of the so-called XYZ states is a long-standing problem. It has been suggested that such particles may be described as compact four-quark states or loosely bound meson molecules. In the present work we analyze the Zc(')→ηcρ decay using both approaches. Such channel might provide useful insights on the nature of the Zc('), helping discriminating between the two different models. © 2015 The Authors. Source

Speleers H.,University of Rome Tor Vergata
Computer Aided Geometric Design | Year: 2015

We consider a C1 cubic spline space defined over a triangulation with Powell-Sabin refinement. The space has some local C2 super-smoothness and can be seen as a close extension of the classical cubic Clough-Tocher spline space. In addition, we construct a suitable normalized B-spline representation for this spline space. The basis functions have a local support, they are nonnegative, and they form a partition of unity. We also show how to compute the Bézier control net of such a spline in a stable way. © 2015 Published by Elsevier B.V. Source

Verrelli C.M.,University of Rome Tor Vergata
Automatica | Year: 2011

The adaptive learning approach proposed in Del Vecchio, Marino, and Tomei (2003) and Liuzzo, Marino, and Tomei (2007a), which guarantees output tracking of sufficiently smooth periodic reference signals (of known period) for classes of time-invariant nonlinear systems with sufficiently smooth unstructured uncertainties, is considered. By using a slightly different analysis (and in particular less conservative bounds), we show how improved convergence properties can be established while maintaining the same learning control structures. The delayed first arithmetic mean of the Fourier series of the uncertain periodic time function f (of known period) can be used instead of the partial sums of the Fourier series of f to further improve the result: a trigonometric polynomial, whose approximation to f is almost as good as the best approximation of f, is obtained. © 2011 Elsevier Ltd. All rights reserved. Source

Costa R.,University of Rome Tor Vergata
Expert Systems with Applications | Year: 2012

In this paper we evaluate the efficiency and productivity of Intellectual Capital (IC) through the assessment of Bests Practices, that have successfully implemented strategies of Intellectual Capital management. The techniques selected for appraising the productivity of intangibles are the Data Envelopment Analysis (DEA) and the Malmquist Productivity Index (MPI). This approach allows a direct comparison between firms of the same industry in the perspective of improvement through benchmarking. It overcomes one of the main limitations of the current intangibles metrics comparing enterprises on the basis their Intellectual Capital management. The paper gives both academic and practical insights that could be used for the operational and strategic Intellectual Capital management. Actually, the outcome of the application gives to inefficient companies some directions for progress, that should constitute the basis for the formulation of future Intellectual Capital management strategies. Finally, we apply the analysis to the Italian yacht manufacturing sector in order to offer yachting companies guidelines for Intellectual Capital management. © 2011 Elsevier Ltd. All rights reserved. Source

Russo F.,University of Reggio Calabria | Comi A.,University of Rome Tor Vergata
Journal of Urban Planning and Development | Year: 2011

Around the world, interest in urban and metropolitan goods movements is increasing because they account for a substantial share of traffic in urban and metropolitan areas. In this context, many city administrators have implemented measures to mitigate the negative effects of freight transportation. Starting from an analysis of existing studies relative to freight policies implemented at the urban scale in Europe, this paper proposes a general classification of measures adopted at the urban scale and an analysis of expected goals and tested results. Each described measure is analyzed by considering the temporal reference scale (strategic, tactical, and operative) of the actors and decision makers involved. Each measure pursues and is linked to one or more expected goal, and the empirical results obtained in the European cities and demonstrated by specific indicators representing the goal are presented. © 2011 American Society of Civil Engineers. Source

Calabretta S.,University of Rome Tor Vergata
Oncogene | Year: 2015

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive and incurable disease. Poor prognosis is due to multiple reasons, including acquisition of resistance to gemcitabine, the first-line chemotherapeutic approach. Thus, there is a strong need for novel therapies, targeting more directly the molecular aberrations of this disease. We found that chronic exposure of PDAC cells to gemcitabine selected a subpopulation of cells that are drug-resistant (DR-PDAC cells). Importantly, alternative splicing (AS) of the pyruvate kinase gene (PKM) was differentially modulated in DR-PDAC cells, resulting in promotion of the cancer-related PKM2 isoform, whose high expression also correlated with shorter recurrence-free survival in PDAC patients. Switching PKM splicing by antisense oligonucleotides to favor the alternative PKM1 variant rescued sensitivity of DR-PDAC cells to gemcitabine and cisplatin, suggesting that PKM2 expression is required to withstand drug-induced genotoxic stress. Mechanistically, upregulation of the polypyrimidine-tract binding protein (PTBP1), a key modulator of PKM splicing, correlated with PKM2 expression in DR-PDAC cell lines. PTBP1 was recruited more efficiently to PKM pre-mRNA in DR- than in parental PDAC cells. Accordingly, knockdown of PTBP1 in DR-PDAC cells reduced its recruitment to the PKM pre-mRNA, promoted splicing of the PKM1 variant and abolished drug resistance. Thus, chronic exposure to gemcitabine leads to upregulation of PTBP1 and modulation of PKM AS in PDAC cells, conferring resistance to the drug. These findings point to PKM2 and PTBP1 as new potential therapeutic targets to improve response of PDAC to chemotherapy.Oncogene advance online publication, 3 August 2015; doi:10.1038/onc.2015.270. © 2015 Macmillan Publishers Limited Source

Giacobbe A.,University of Rome Tor Vergata
Oncogene | Year: 2015

Metastasis is a multistep cell-biological process, which is orchestrated by many factors, including metastasis activators and suppressors. Metastasis Suppressor 1 (MTSS1) was originally identified as a metastasis suppressor protein whose expression is lost in metastatic bladder and prostate carcinomas. However, recent findings indicate that MTSS1 acts as oncogene and pro-migratory factor in melanoma tumors. Here, we identify and characterized a molecular mechanism controlling MTSS1 expression, which impinges on a pro-tumorigenic role of MTSS1 in breast tumors. We found that in normal and in cancer cell lines ΔNp63 is able to drive the expression of MTSS1 by binding to a p63-binding responsive element localized in the MTSS1 locus. We reported that ΔNp63 is able to drive the migration of breast tumor cells by inducing the expression of MTSS1. Notably, in three human breast tumors data sets the MTSS1/p63 co-expression is a negative prognostic factor on patient survival, suggesting that the MTSS1/p63 axis might be functionally important to regulate breast tumor progression.Oncogene advance online publication, 29 June 2015; doi:10.1038/onc.2015.230. © 2015 Macmillan Publishers Limited Source

Latina A.,University of Rome Tor Vergata
Oncogene | Year: 2015

During physiological aerobic metabolism, the epidermis undergoes significant oxidative stress as a result of the production of reactive oxygen species (ROS). To maintain a balanced oxidative state, cells have developed protective antioxidant systems, and preliminary studies suggest that the transcriptional factor p63 is involved in cellular oxidative defence. Supporting this hypothesis, the ΔNp63α isoform of p63 is expressed at high levels in the proliferative basal layer of the epidermis. Here we identify the CYGB gene as a novel transcriptional target of ΔNp63 that is involved in maintaining epidermal oxidative defence. The CYGB gene encodes cytoglobin, a member of the globin protein family, which facilitates the diffusion of oxygen through tissues and acts as a scavenger for nitric oxide or other ROS. By performing promoter activity assays and chromatin immunoprecipitation, reverse transcriptase quantitative PCR and western blotting analyses, we confirm the direct regulation of CYGB by ΔNp63α. We also demonstrate that CYGB has a protective role in proliferating keratinocytes grown under normal conditions, as well as in cells treated with exogenous hydrogen peroxide. These results indicate that ΔNp63, through its target CYGB has an important role in the cellular antioxidant system and protects keratinocytes from oxidative stress-induced apoptosis. The ΔNp63–CYGB axis is also present in lung and breast cancer cell lines, indicating that CYGB-mediated ROS-scavenging activity may also have a role in epithelial tumours. In human lung cancer data sets, the p63–CYGB interaction significantly predicts reduction of patient survival.Oncogene advance online publication, 22 June 2015; doi:10.1038/onc.2015.222. © 2015 Macmillan Publishers Limited Source

Bifaretti S.,University of Rome Tor Vergata
2013 IEEE Energy Conversion Congress and Exposition, ECCE 2013 | Year: 2013

International Standards impose to Distributed Energy Resources, connected to the grid by an inverter, to detect an islanding condition within a suitable time interval. In this paper a Phase Locked Loop (PLL), based on a third-order prediction-correction filter, is proposed to implement an islanding detector with reduced detection time. Such feature is obtained using the estimation of the grid angular frequency and acceleration provided by the PLL with a negligible time delay. The proposed approach is implemented on a DSP and validated through an experimental comparison among different detection methods, such as Rate of Change of Frequency (ROCOF) and Sleep Mode frequency Shift (SMS). A combined use of ROCOF and SMS is also illustrated and discussed. © 2013 IEEE. Source

Di Renzo L.,University of Rome Tor Vergata
European review for medical and pharmacological sciences | Year: 2013

Strategies to improve weight maintenance are focused on considering the genetic makeup and its interaction with dietary intake, with the aim to identify vulnerable individuals that will benefit from a variety of more personalized dietary recommendations. The aim of the study was to examine the impact of the C677T MTHFR gene Polymorphism on body composition changes induced by a balanced hypocaloric Italian Mediterannean diet (IMD). Participation in the study included a complete screening of anthropometry and body composition by Dual-energy X-ray absorptiometry (DXA), and a genotyping for the C677T MTHFR polymorphism. 70 Italian Caucasian obese were enrolled and 56 of them completed the screening at baseline and 12 weeks after the nutritional intervention. T(+) carriers had a higher content of Total Body Fat (TBFat), and Lean (TBLean), reflecting on higher weight and BMI, than T(-) carriers. After IMD, the 28.6% and 71.4% of total subjects decreased weight and TBFat (Kg), respectively. The relative changes were: delta % = -9.09±3.85 for weight; delta % = -15.79±8.51 for TBFat; delta % = -3.80±5.60 for TBLean. The 5.3% of subjects who reached the end point of intervention, and the 8.9% who reduced TBFat (%) below the cut-off of preobesity, were T(-) carriers. A loss of TBLean (Kg) was observed in the 5.1% and 23.5% of T(-) and T(+) carriers. MTHFR genetic variations analysis would be an innovative tool for the nutritional assessment, in order to predict the therapeutic response of obese subjects, in terms of fat and lean mass loss. Source

Novelli G.,University of Rome Tor Vergata
Internal and Emergency Medicine | Year: 2010

Personalized medicine provide to physicians a molecular makeup of each patient. Looking at the patient on this level helps the physician get a profile of the patient's genetic distinction, or mapping. By investigating this genetic profile, medical professionals are then able to select patients, and use the found information to plan out a course of treatment that is much more in step with the way their body works. Personalize medicine is a direct extension of the genomic medicine that use genetic information to prevent or treat disease in adults or their children. © 2010 SIMI. Source

Koch G.,Laboratorio Of Neurologia Clinica E Comportamentale | Koch G.,University of Rome Tor Vergata
Functional Neurology | Year: 2010

Non-invasive brain stimulation methods, such as repetitive transcranial magnetic stimulation (rTMS), are currently used to modulate the excitability of the cerebral cortex, providing important insights into mechanisms of cortical plasticity. Used to create long-lasting changes in the excitability of synapses, rTMS has been intensively investigated as a therapeutic tool in several neurological and psychiatric conditions and given some promising results. Recent studies have shown that rTMS of cerebellar structures is capable of inducing long-lasting changes in the excitability of cerebellothalamo-cortical pathways. Thus, this novel approach may be important for investigating the functions of cerebellar plasticity. Indeed, cerebellar rTMS has been shown to modulate motor control, cognitive functions, emotion and mood. Moreover, recent studies seem to indicate that long-lasting modifications of cerebellar pathways could be usefully exploited in the treatment of several pathological conditions characterized by altered cortical excitability, such as Parkinson's disease, stroke, depression and schizophrenia. The high potential of cerebellar rTMS as a therapeutic tool in neurology could depend on the possibility of modulating several interconnected remote areas, through the activation of different systems, such as the cerebello-thalamo-cortical and limbic-thalamo-cortical networks. © CIC Edizioni Internazionali. Source

Lorenz R.D.,Johns Hopkins University | Newman C.,Ashima Research | Newman C.,California Institute of Technology | Lunine J.I.,University of Rome Tor Vergata
Icarus | Year: 2010

Motivated by radar and near-infrared data indicating that Titan's polar lakes are extremely smooth, we consider the conditions under which a lake surface will be ruffled by wind to form capillary waves. We evaluate laboratory data on wind generation and derive, without scaling for surface tension effects, a threshold for pure methane/ethane of ∼0.5-1. m/s. However, we compute the physical properties of predicted Titan lake compositions using the National Institute for Standards Technology (NIST) code and note that dissolved amounts of C3 and C4 compounds are likely to make Titan lakes much more viscous than pure ethane or methane, even without allowing for suspended particulates which would increase the viscosity further. Wind tunnel experiments show a strong dependence of capillary wave growth on liquid viscosity, and this effect may explain the apparent absence so far of waves, contrary to prior expectations that generation of gravity waves by wind should be easy on Titan. On the other hand, we note that winds over Titan lakes predicted with the TitanWRF Global Circulation Model indicate radar observations so far have in any case been when winds have been low (∼0.5-0.7. m/s), possibly below the wave generation threshold, while peak winds during summer may reach 1-2. m/s. Thus observations of Titan's northern lakes during the coming years by the Cassini Solstice mission offer the highest probability of observing wind-roughening of lake surfaces, while observations of Ontario Lacus in the south will likely continue to show it to be flat and smooth. © 2009. Source

Cazzola M.,University of Rome Tor Vergata | Page C.P.,Kings College London | Calzetta L.,San Raffaele Pisana Hospital | Matera M.G.,The Second University of Naples
European Respiratory Journal | Year: 2012

The hallmark of chronic obstructive pulmonary disease (COPD) is an enhanced or abnormal inflammatory immune response of the lungs to inhaled particles and gases, usually from cigarette smoke, characterised by increased numbers of neutrophils, activated macrophages and activated T-lymphocytes (Tc1 and Th1 cells). Therefore, suppression of the inflammatory response is a logical approach to the treatment of COPD. Despite the inflammatory nature of COPD, currently available anti-inflammatory therapies provide little or no benefit in COPD patients and may have detrimental effects. For this reason, there is an urgent need to discover effective and safe anti-inflammatory treatments that might prevent the relentless progression of the disease. In recent years, attention has largely been focused on inhibition of recruitment and activation of inflammatory cells, and on antagonism of their products. In this review, we put together a summary of the state-of-the-art development of clearly and/or potentially useful anti-inflammatory strategies in COPD. Copyright©ERS 2012. Source

Scapagnini G.,University of Molise | Davinelli S.,University of Molise | Drago F.,University of Catania | De Lorenzo A.,University of Rome Tor Vergata | Oriani G.,University of Molise
CNS Drugs | Year: 2012

Depression is a medical condition with a complex biological pattern of aetiology, involving genetic and epigenetic factors, along with different environmental stressors. Recent evidence suggests that oxidative stress processes might play a relevant role in the pathogenic mechanism(s) underlying many major psychiatric disorders, including depression.Reactive oxygen and nitrogen species have been shown to modulate levels and activity of noradrenaline (norepinephrine), serotonin, dopamine and glutamate, the principal neurotransmitters involved in the neurobiology of depression. Major depression has been associated with lowered concentrations of several endogenous antioxidant compounds, such as vitamin E, zinc and coenzyme Q10, or enzymes, such as glutathione peroxidase, and with an impairment of the total antioxidant status. These observations introduce new potential targets for the development of therapeutic interventions based on antioxidant compounds.The present review focuses on the possible role of oxidative stress processes in the pathogenesis of depression. The therapeutic potential of antioxidant compounds as a co-adjuvant treatment to conventional antidepressants is discussed. For instance, N-acetyl-cysteine has been shown to have a significant benefit on depressive symptoms in a randomized placebo-controlled trial. Additionally, curcumin, the yellow pigment of curry, has been shown to strongly interfere with neuronal redox homeostasis in the CNS and to possess antidepressant activity in various animal models of depression, also thanks to its ability to inhibit monoamine oxidases. There is an urgent need to develop better tolerated and more effective treatments for depressive disorders and several antioxidant treatments appear promising and deserve further study. © 2012 Springer International Publishing AG. All rights reserved. Source

Luo H.,University of Hamburg | Wen C.,University of Rome Tor Vergata
Journal of High Energy Physics | Year: 2016

Abstract: We establish a set of new on-shell recursion relations for amplitudes satisfying soft theorems. The recursion relations can apply to those amplitudes whose additional physical inputs from soft theorems are enough to overcome the bad large-z behaviour. This work is a generalization of the recursion relations recently obtained by Cheung et al. for amplitudes in scalar effective field theories with enhanced vanishing soft behaviours, which can be regarded as a special case of those with non-vanishing soft limits. We apply the recursion relations to tree-level amplitudes in various theories, including amplitudes in the Akulov-Volkov theory and amplitudes containing dilatons of spontaneously-broken conformal symmetry. © 2016, The Author(s). Source

Meda A.,University of Rome Tor Vergata | Minelli F.,University of Brescia | Plizzari G.A.,University of Brescia
Composites Part B: Engineering | Year: 2012

Even though a number of research studies have demonstrated the effectiveness of Fibre Reinforced Concrete (FRC) in improving the structural response of RC members under different loading conditions, some concerns recently arose on the sectional ductility under flexure which can be reduced under specific conditions. In fact, fibres do not significantly increase the ultimate moment of RC members and, with rather tough FRC and low strain-hardening ratio of the longitudinal rebars, the rotation capacity can substantially decrease owing to a cracking localization at ultimate limit state. This paper focuses on this topic with a number of experimental results on full-scale FRC beams tested under flexure. Experimental results evidence that fibres, when provided in sufficient amount, are able to move the beam failure from concrete crushing to steel rupture. Under certain circumstances, the overall ductility, measured in terms of displacements, may decrease. On the other hand, in all cases the addition of fibres determines a stiffer and in general enhanced post-cracking behaviour in service conditions. © 2011 Elsevier Ltd. All rights reserved. Source

Maruotti A.,Third University of Rome | Rocci R.,University of Rome Tor Vergata
Statistics in Medicine | Year: 2012

Hidden Markov models (HMMs) are frequently used to analyse longitudinal data, where the same set of subjects is repeatedly observed over time. In this context, several sources of heterogeneity may arise at individual and/or time level, which affect the hidden process, that is, the transition probabilities between the hidden states. In this paper, we propose the use of a finite mixture of non-homogeneous HMMs (NH-HMMs) to face the heterogeneity problem. The non-homogeneity of the model allows us to take into account observed sources of heterogeneity by means of a proper set of covariates, time and/or individual dependent, explaining the variations in the transition probabilities. Moreover, we handle the unobserved sources of heterogeneity at the individual level, due to, for example, omitted covariates, by introducing a random term with a discrete distribution. The resulting model is a finite mixture of NH-HMM that can be used to classify individuals according to their dynamic behaviour or to estimate a mixed NH-HMM without any assumption regarding the distribution of the random term following the non-parametric maximum likelihood approach. We test the effectiveness of the proposal through a simulation study and an application to real data on alcohol abuse. © 2012 John Wiley & Sons, Ltd. Source

Tomassini L.,University of Chieti Pescara | Tomassini L.,University of Gottingen | Viaggiu S.,University of Rome Tor Vergata
Classical and Quantum Gravity | Year: 2011

We derive new spacetime uncertainty relations (STUR) at the fundamental Planck length LP from quantum mechanics and general relativity, both in flat and curved backgrounds. Contrary to claims present in the literature, our approach suggests that no minimal uncertainty appears for lengths, but instead for minimal space and four-volumes. Moreover, we derive a maximal absolute value for the energy density. Finally, some considerations on possible commutators among quantum operators implying our STUR are given. © 2011 IOP Publishing Ltd. Source

Liotta G.,University of Rome Tor Vergata
PloS one | Year: 2013

HIV infection is a major contributor to maternal mortality in resource-limited settings. The Drug Resource Enhancement Against AIDS and Malnutrition Programme has been promoting HAART use during pregnancy and postpartum for Prevention-of-mother-to-child-HIV transmission (PMTCT) irrespective of maternal CD4 cell counts since 2002. Records for all HIV+ pregnancies followed in Mozambique and Malawi from 6/2002 to 6/2010 were reviewed. The cohort was comprised by pregnancies where women were referred for PMTCT and started HAART during prenatal care (n = 8172, group 1) and pregnancies where women were referred on established HAART (n = 1978, group 2). 10,150 pregnancies were followed. Median (IQR) baseline values were age 26 years (IQR:23-30), CD4 count 392 cells/mm(3) (IQR:258-563), Viral Load log10 3.9 (IQR:3.2-4.4), BMI 23.4 (IQR:21.5-25.7), Hemoglobin 10.0 (IQR: 9.0-11.0). 101 maternal deaths (0.99%) occurred during pregnancy to 6 weeks postpartum: 87 (1.1%) in group 1 and 14 (0.7%) in group 2. Mortality was 1.3% in women with Source

Jevnikar A.,University of Rome Tor Vergata
Advanced Nonlinear Studies | Year: 2016

We are concerned with the class of equations with exponential nonlinearities -Δu=ρ 1 he u Σ he u dV g - 1 |Σ|-ρ 2 he -u Σ he -u dV g - 1 |Σ|$- \Delta u = \rho -1 \Biggl ( \frac{h e^{u}}{\int -\Sigma h e^{u} \,dV-g} - \frac{1}{|\Sigma |} \Biggr ) - \rho -2 \Biggl ( \frac{h e^{-u}}{\int -\Sigma h e^{-u} \,dV-g} - \frac{1}{|\Sigma |} \Biggr )$ on a compact surface Σ, which describes the mean field equation of equilibrium turbulence with arbitrarily signed vortices. Here, h is a smooth positive function and ρ 1 ,ρ 2 ${\rho -1, \rho -2}$ are two positive parameters. We provide the first multiplicity result for this class of equations by using Morse theory. © 2016 by De Gruyter. Source

Oliva F.,University of Rome Tor Vergata | Frizziero A.,University of Padua | Maffulli N.,Queen Mary, University of London | Maffulli N.,University of Salerno
Muscles, Ligaments and Tendons Journal | Year: 2013

The design, implementation, evaluation, interpretation and report of research is a key important for the science. The researc required minimize the uncertainty, therefore we encourage all authors of respect how much can possible the contents in this official editorial also in order to stimulate interest and debate about constructive change in the use of statistics in our disciplines1,2. Authors are required to confirm that these standards and laws have been adhered to by formally citing this editorial within the methods section of their own manuscript. Source

Oleas J.,University of Florida | Yokoi F.,University of Florida | Deandrade M.P.,University of Florida | Pisani A.,University of Rome Tor Vergata | Li Y.,University of Florida
Movement Disorders | Year: 2013

Dystonia is a neurological disorder characterized by abnormal involuntary movements that are prolonged and often cause twisting and turning. Several genetically modified worms, fruit flies, and rodents have been generated as models of genetic dystonias, in particular DYT1, DYT11, and DYT12 dystonias. Although these models do not show overt dystonic symptoms, the rodent models exhibit motor deficits in specialized behavioral tasks, such as the rotarod and beam-walking tests. For example, in a rodent model of DYT12 dystonia, which is generally stress triggered, motor deficits are observed only after the animal is stressed. Moreover, in a rodent model of DYT1 dystonia, the motor and electrophysiological deficits can be rescued by trihexyphenidyl, a common anticholinergic medication used to treat dystonic symptoms in human patients. Biochemically, the DYT1 and DYT11 animal models also share some similarities to patients, such as a reduction in striatal D2 dopamine receptor and binding activities. In addition, conditional knockout mouse models for DYT1 and DYT11 dystonia demonstrate that loss of the causal dystonia-related proteins in the striatum leads to motor deficits. Interestingly, loss of the DYT1 dystonia causal protein in Purkinje cells shows an improvement in motor performance, suggesting that gene therapy targeting of the cerebellum or intervention in its downstream pathways may be useful. Finally, recent studies using DYT1 dystonia worm and mouse models led to a potential novel therapeutic agent, which is currently undergoing clinical trials. These results indicate that genetic animal models are powerful tools to elucidate the pathophysiology and to further develop new therapeutics for dystonia. © 2013 Movement Disorder Society. Source

Pacchiarotti A.,University of Rome La Sapienza | Caserta D.,University of Rome La Sapienza | Sbracia M.,University of Rome Tor Vergata | Moscarini M.,University of Rome La Sapienza
Fertility and Sterility | Year: 2011

The objective of this study was to test the expression of the oct-4 and c-kit, both markers of stem cells, in the ectopic endometrial tissue of endometriotic lesions of women with severe endometriosis. Our findings show that ectopic epithelial cells express oct-4 and c-kit and this suggests that the ectopic endometrium in endometriosis has a stem cell origin and could explain the possible progression to ovarian cancer. ©2011 by American Society for Reproductive Medicine. Source

Semplici S.,University of Rome Tor Vergata
Medicine, Health Care and Philosophy | Year: 2011

The publication of the Report of the International Bioethics Committee of Unesco on Social responsibility and health provides an opportunity to reshape the conceptual framework of the right to health care and its practical implications. The traditional distinctions between negative and positive, civil-political and economic-social, legal and moral rights are to be questioned and probably overcome if the goal is to pursue 'the highest attainable standard of health' as a fundamental human right, that should as such be guaranteed to every human being. What we are called upon to, is the commitment not to exclude now and forever anyone from having access to the 'excellence' of scientific and medical progress. Therefore, the addressees of this 'responsibility' cannot be just the governments and the states within the limits of their 'jurisdiction'. The challenge is to tackle at the same time the social and global determinants of health. © 2011 Springer Science+Business Media B.V. Source

Huang Y.-T.,National Taiwan University | Wen C.,University of Rome Tor Vergata
Journal of High Energy Physics | Year: 2015

Abstract: We discuss constraints imposed by soft limits for effective field theories arising from symmetry breaking. In particular, we consider those associated with anomalous conformal symmetry as well as duality symmetries in supergravity. We verify these soft theorems for the dilaton effective action relevant for the a-theorem, as well as the one-loop effective action for N=4 supergravity. Using the universality of leading transcendental coefficients in the α′ expansion of string theory amplitudes, we study the matrix elements of operator R4 with half maximal supersymmetry. We construct the non-linear completion of R4 that satisfies both single and double soft theorems up to seven points. This supports the existence of duality invariant completion of R4. © 2015, The Author(s). Source

Chen W.-M.,National Taiwan University | Huang Y.-T.,National Taiwan University | Huang Y.-T.,Institute for Advanced Study | Wen C.,University of Rome Tor Vergata
Journal of High Energy Physics | Year: 2015

Abstract: We consider constraints on higher-dimensional operators for supersymmetric effective field theories. In four dimensions with maximal supersymmetry and SU(4) R-symmetry, we demonstrate that the coefficients of abelian operators Fn with MHV helicity configurations must satisfy a recursion relation, and are completely determined by that of F4. As the F4 coefficient is known to be one-loop exact, this allows us to derive exact coefficients for all such operators. We also argue that the results are consistent with the SL(2,Z) duality symmetry. Breaking SU(4) to Sp(4), in anticipation for the Coulomb branch effective action, we again find an infinite class of operators whose coefficients are determined exactly. We also consider three-dimensional N$$\mathcal{N}$$ = 8 as well as six-dimensional N$$\mathcal{N}$$ = (2,0),(1,0) and (1,1) theories. In all cases, we demonstrate that the coefficient of dimension-six operator must be proportional to the square of that of dimension-four. © 2015, The Author(s). Source

Bianchi M.,University of Rome Tor Vergata | He S.,Institute for Advanced Study | He S.,Perimeter Institute for Theoretical Physics | Huang Y.-T.,Institute for Advanced Study | And 2 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2015

We study soft theorems in a broader context, their universality in effective field theories and string theory, as well as continue the analysis of their fate at loop level. In effective field theories with F3 and R3 interactions, the soft theorems are not modified. However, for gravity theories with R2φ interactions, the sub-subleading order soft graviton theorem, which is beyond what is implied by the extended Bondi, van der Burg, Metzner, and Sachs symmetry, requires modifications at tree level for nonsupersymmetric theories and at loop level for N≤4 supergravity due to anomalies. For open and closed superstrings at finite α′, via explicit calculation for lower-point examples as well as world sheet operator product expansion analysis for arbitrary multiplicity, we show that scattering amplitudes satisfy the same soft theorem as their field-theory counterpart. This is no longer true for closed bosonic or heterotic strings due to the presence of R2φ interactions. We also consider loop corrections to gauge theories in the planar limit, where we show that tree-level soft gluon theorems are respected at the integrand level for 1≤N≤4 SYM. Finally, we discuss the fate of soft theorems for finite loop amplitudes in pure Yang-Mills theory and gravity. © 2015 American Physical Society. Source

Viaggiu S.,University of Rome Tor Vergata
General Relativity and Gravitation | Year: 2015

Recently, we have generalized the Bekenstein–Hawking entropy formula for black holes embedded in expanding Friedmann universes. In this letter, we begin the study of this new formula to obtain the first law of thermodynamics for dynamical apparent horizons. In this regard we obtain a generalized expression for the internal energy U together with a distinction between the dynamical temperature TD of apparent horizons and the related one due to thermodynamics formulas. Remarkable, when the expression for U is applied to the apparent horizon of the universe, we found that this internal energy is a constant of motion. Our calculations thus show that the total energy of our spatially flat universe including the gravitational contribution, when calculated at the apparent horizon, is an universal constant that can be set to zero from simple dimensional considerations. This strongly support the holographic principle. © 2015, Springer Science+Business Media New York. Source

Barbaranelli C.,University of Rome La Sapienza | Lee C.S.,Oregon Health And Science University | Vellone E.,University of Rome Tor Vergata | Riegel B.,University of Pennsylvania
Research in Nursing and Health | Year: 2014

The Self-Care of Heart Failure Index (SCHFI) is used widely, but issues with reliability have been evident. Cronbach alpha coefficient is usually used to assess reliability, but this approach assumes a unidimensional scale. The purpose of this article is to address the dimensionality and internal consistency reliability of the SCHFI. This was a secondary analysis of data from 629 adults with heart failure enrolled in three separate studies conducted in the northeastern and northwestern United States. Following testing for scale dimensionality using confirmatory factor analysis, reliability was tested using coefficient alpha and alternative options. Confirmatory factor analysis demonstrated that: (a) the Self-Care Maintenance Scale has a multidimensional four-factor structure; (b) the Self-Care Management Scale has a two-factor structure, but the primary factors loaded on a common higher-order factor; and (c) the Self-Care Confidence Scale is unidimensional. Reliability estimates for the three scales, obtained with methods compatible with each scale's dimensionality, were adequate or high. The results of the analysis demonstrate that issues of dimensionality and reliability cannot be separated. Appropriate estimates of reliability that are consistent with the dimensionality of the scale must be used. In the case of the SCHFI, coefficient alpha should not be used to assess reliability of the self-care maintenance and the self-care management scales, due to their multidimensionality. When performing psychometric evaluations, we recommend testing dimensionality before assessing reliability, as well using multiple indices of reliability, such as model-based internal consistency, composite reliability, and omega and maximal reliability coefficients. © 2014 Wiley Periodicals, Inc. Source

Ascione F.,University of Rome Tor Vergata
Mechanics Research Communications | Year: 2010

The first results of a numerical and experimental investigation on the shear forces distribution in a bolted joint made entirely from FRP materials are presented. It is also proposed an experimental equipment for investigating the strains and stresses distributions around the holes of the connection as well as the bearing stresses at the interface between plate and steel bolt. A good agreement between numerical and experimental results allows to use the proposed testing set-up for analysing the bearing failure of several joint configuration with different lamination scheme, geometry and type of load. © 2010 Elsevier Ltd. All rights reserved. Source

Chen W.-M.,National Taiwan University | Huang Y.-T.,National Taiwan University | Huang Y.-T.,Institute for Advanced Study | Wen C.,University of Rome Tor Vergata
Physical Review Letters | Year: 2015

Soft limits of a massless S matrix are known to reflect the symmetries of the theory. In particular, for theories with Goldstone bosons, the double-soft limit of scalars reveals the coset structure of the vacuum manifold. In this Letter, we propose that such universal double-soft behavior is not only true for scalars, but also for spin-1/2 particles in four dimensions and fermions in three dimensions. We first consider the Akulov-Volkov theory and demonstrate that the double-soft limit of Goldstinos yields the supersymmetry algebra. More surprisingly, we also find that amplitudes in 4≤N≤8 supergravity theories in four dimensions as well as N=16 supergravity in three dimensions behave universally in the double-soft-fermion limit, analogous to the scalar ones. The validity of the new soft theorems at loop level is also studied. The results for supergravity are beyond what is implied by supersymmetry Ward identities and may impose nontrivial constraints on the possible counterterms for supergravity theories. © 2015 American Physical Society. © 2015 American Physical Society. Source

Volovich A.,Brown University | Wen C.,University of Rome Tor Vergata | Zlotnikov M.,Brown University
Journal of High Energy Physics | Year: 2015

Abstract: We investigate the tree-level S-matrix in gauge theories and open superstring theory with several soft particles. We show that scattering amplitudes with two or three soft gluons of non-identical helicities behave universally in the limit, with multi-soft factors which are not the product of individual soft gluon factors. The results are obtained from the BCFW recursion relations in four dimensions, and further extended to arbitrary dimensions using the CHY formula. We also find new soft theorems for double soft limits of scalars and fermions in N=4 and pure N=2 SYM. Finally, we show that the double-soft-scalar theorems can be extended to open superstring theory without receiving any α′ corrections. © 2015, The Author(s). Source

Carbone M.,University of Rome Tor Vergata
Surface and Interface Analysis | Year: 2015

Formic acid is the simplest of the carboxylic acids and a model adsorption system for several surfaces. In spite of the simple structure, formic acid reactivity and photoreactivity may be quite complex. In this paper, a study is presented on the deuterated formic acid adsorption on Si(111)7x7 at room temperature. The study is performed both by valence band photoemission and by photon-stimulated desorption as a function of time and of photon energy in the 90-120 eV range. A primarily adsorption on rest atoms is found. This is verified by monitoring rest atoms and adatom intensity as a function of formic acid exposure. Further checks were made to control that surface adatoms were still free to react after the adsorption of formic acid. The photon stimulated desorption produces 5 single positively charged fragments: D+, O+, OD+ CO+ and CDO+. Possible fragmentation mechanisms are discussed. Copyright © 2014 John Wiley & Sons, Ltd. Source

Pietropaolo A.,University of Rome Tor Vergata
Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment | Year: 2012

Localized neutron beam monitors are very useful for applications related to the measurement of the so called single event effects (SEE) in electronic devices, especially at spallation neutron sources. Although the high-energy component of the spectrum typically represents a concern for SEE, nevertheless the measurement of the flux over the whole energy range is also desirable. Indeed, the possibility of measuring the spectral neutron fluence rate is instrumental for a reliable and complete assessment of the robustness of the irradiated devices to SEE induced by neutron fields that close resemble the atmospheric one, that extends up to 10 9 eV energy. In this paper, an approach to monitor the epithermal energy region of the pulsed neutrons beams available at the ISIS spallation neutron source is presented. It is based on the exploitation of the resonances of the 235U(n,f) reaction and the detection of the fission fragments by means of single crystal diamonds. These explorative tests are intended as complementary to the use of diamond detectors for localized fast neutron beams monitoring and the results obtained, while assessing this aspect, also show the possibility to measure the relative spectral neutron fluence rate at different energies in the electronvolt region. © 2012 Elsevier B.V. All rights reserved. Source

Pigolotti S.,Niels Bohr Institute | Pigolotti S.,Polytechnic University of Catalonia | Benzi R.,University of Rome Tor Vergata | Jensen M.H.,Niels Bohr Institute | Nelson D.R.,Harvard University
Physical Review Letters | Year: 2012

We study competition between two biological species advected by a compressible velocity field. Individuals are treated as discrete Lagrangian particles that reproduce or die in a density-dependent fashion. In the absence of a velocity field and fitness advantage, number fluctuations lead to a coarsening dynamics typical of the stochastic Fisher equation. We investigate three examples of compressible advecting fields: a shell model of turbulence, a sinusoidal velocity field and a linear velocity sink. In all cases, advection leads to a striking drop in the fixation time, as well as a large reduction in the global carrying capacity. We find localization on convergence zones, and very rapid extinction compared to well-mixed populations. For a linear velocity sink, one finds a bimodal distribution of fixation times. The long-lived states in this case are demixed configurations with a single interface, whose location depends on the fitness advantage. © 2012 American Physical Society. Source

Sacca S.C.,Ophthalmology Unit | Centofanti M.,University of Rome Tor Vergata | Izzotti A.,University of Genoa
Investigative Ophthalmology and Visual Science | Year: 2012

PURPOSE. The aim of this study was to investigate the expression level of several biomarkers in the in the aqueous humor of 14 patients with primary open angle glaucoma who underwent glaucoma surgery, and 11 nonglaucomatous normals who underwent cataract extraction surgery. METHODS. The aqueous humor proteome of 25 patients was analyzed using an antibody microarray. Fourteen patients with uncontrolled intraocular pressure-despite profound therapeutic interventions-who underwent filtering procedures and 11 control subjects who underwent surgery for senile cataracts were included in the present study. Protein expression was evaluated using Cy3/Cy5 labeling, column purification, and hybridization on antibody-spotted glass microarrays. Fluorescent signals were detected by fluorescence laser scanning. RESULTS. The levels of 13 proteins were significantly increased in the aqueous humor of glaucomatous patients compared with expression levels in healthy controls. One of the 13 proteins (ELAM 1) was involved in inflammation. Two of these proteins (apolipoprotein B and E) were involved in the delivery of cholesterol to cells. Five of the 13 proteins (myotrophin, myoblast determination protein 1, myogenin, vasodilatorstimulated phosphoprotein, and ankyrin-2) were involved in muscle cell differentiation and function. Three proteins (heat shock 60 kilodaltons (kDa) and 90 kDa proteins, and ubiquitin fusion degradation 1-like) were involved in stress response and the removal of damaged proteins; and two proteins (phospholipase C β and γ) were involved in signal transduction and neural development. CONCLUSIONS. The expressions of these proteins in the aqueous humor of glaucomatous patients reflect the damage occurring in anterior chamber endothelia, mainly including the trabecular meshwork, which is the main structure of this ocular segment injured by glaucoma. © 2012 The Association for Research in Vision and Ophthalmology, Inc. Source

Padulo J.,University of Rome Tor Vergata | Capua R.D.,University of Molise | Viggiano D.,University of Molise
European Journal of Applied Physiology | Year: 2012

Variability of cycle-to-cycle duration during a pedaling task is probably related to the rhythmic control of the lower limb muscles as in gait. Although walking variability has been extensively studied for its clinical and physiological implications, pedaling variability has received little attention. The present contribution determines the variability of the cycling time during a 10-min exercise as a function of upper body position. Nine healthy males were required to pedal on cycle-ergometer at a selfselected speed for 10 min in two different upper body positions [hands on upper handlebars (UP) or lower handlebars (DP)]. Time domain measures of cycling variability [total standard deviation (SDtot), mean standard deviation cycle-to-cycle intervals over 100 cycles (SD100), standard deviation of the average cycle-to-cycle intervals over 100 cycles (SDA100)] were measured. Moreover, the same time domain measures were also calculated for heart rate in order to discriminate possible involvements of autonomic regulation. Finally, the structure of the cycle variations has been analyzed in the framework of deterministic chaos calculating the maximum Lyapunov exponents. Significant increases in cycle-to-cycle variability were found for SDtot, SD100 in DP compared to UP, whereas cardiac parameters and other cycling parameters were not changed in the two positions. Moreover, the maximum Lyapunov exponent was significantly more negative in DP. The results suggest that small perturbations of upper body position can influence the control of cycling rhythmicity by increasing the variability in a dissipative deterministic regimen. © Springer-Verlag 2011. Source

Dall'Agata G.,University of Padua | Dall'Agata G.,National Institute of Nuclear Physics, Italy | Inverso G.,University of Rome Tor Vergata | Inverso G.,National Institute of Nuclear Physics, Italy
Nuclear Physics B | Year: 2012

We discuss a simple procedure for finding vacua of gauged supergravity models, based on the variation of the embedding tensor rather than on a direct minimization of the scalar potential. We apply this procedure to N=8 gauged supergravity in 4 dimensions. We easily recover many of the previously known vacua, also completing their scalar mass spectrum, and we apply our procedure to find a dozen of new analytical vacuum solutions. The analysis shows an interesting structure on the moduli spaces of these vacua and provides new criteria to determine the expected value of the cosmological constant by a simple inspection of the group properties of the embedding tensor. © 2012 Elsevier B.V. Source

Morselli A.,University of Rome Tor Vergata
Acta Physica Polonica B | Year: 2012

Successfully launched in June 2008, the Fermi Gamma-ray Space Telescope, formerly named GLAST, has been observing the high-energy gammaray sky with unprecedented sensitivity in the 20 MeV-300 GeV energy range and electrons + positrons in the 7 GeV-1 TeV range, opening a new observational window on a wide variety of astrophysical objects. Source

Orlandi A.,University of Rome Tor Vergata
International Journal of Stem Cells | Year: 2015

Intimal accumulation of smooth muscle cells contributes to the development and progression of atherosclerotic lesions and restenosis following endovascular procedures. Arterial smooth muscle cells display heterogeneous phenotypes in both physiological and pathological conditions. In response to injury, dedifferentiated or synthetic smooth muscle cells proliferate and migrate from the tunica media into the intima. As a consequence, smooth muscle cells in vascular lesions show a prevalent dedifferentiated phenotype compared to the contractile appearance of normal media smooth muscle cells. The discovery of abundant stem antigen-expressing cells in vascular lesions also rarely detected in the tunica media of normal adult vessels stimulated a great scientific debate concerning the possibility that proliferating vascular wall-resident stem cells accumulate into the neointima and contribute to the progression of lesions. Although several experimental studies support this hypothesis, others researchers suggest a positive effect of stem cells on plaque stabilization. So, the real contribute of vascular wall-resident stem cells to pathological vascular remodelling needs further investigation. This review will examine the evidence and the contribution of vascular wall-resident stem cells to arterial pathobiology, in order to address future investigations as potential therapeutic target to prevent the progression of vascular diseases. Source

Bernardi M.,Massachusetts Institute of Technology | Palummo M.,University of Rome Tor Vergata | Grossman J.C.,Massachusetts Institute of Technology
Physical Review Letters | Year: 2012

We explain the nature of the electronic energy gap and optical absorption spectrum of carbon-boron-nitride (CBN) monolayers using density functional theory, GW and Bethe-Salpeter calculations. The band structure and the optical absorption are regulated by the C domain size rather than the composition (as customary for bulk semiconductor alloys). The C and BN quasiparticle states lie at separate energy for C and BN, with little mixing for energies near the band edge where states are chiefly C in character. The resulting optical absorption spectra show two distinct peaks whose energy and relative intensity vary with composition in agreement with the experiment. The monolayers present strongly bound excitons localized within the C domains, with binding energies of the order of 0.5-1.5 eV dependent on the C domain size. The optoelectronic properties result from the overall monolayer band structure, and cannot be understood as a superposition of the properties of bulklike C and BN domains. © 2012 American Physical Society. Source

Giuliani A.,Third University of Rome | Mastropietro V.,University of Rome Tor Vergata | Porta M.,ETH Zurich
Annals of Physics | Year: 2012

The effects of gauge interactions in graphene have been analyzed up until now in terms of effective models of Dirac fermions. However, in several cases lattice effects play an important role and need to be taken consistently into account. In this paper, we introduce and analyze a lattice gauge theory model for graphene, which describes tight binding electrons hopping on the honeycomb lattice and interacting with a three-dimensional quantum U(1) gauge field. We perform an exact renormalization group analysis, which leads to a renormalized expansion that is finite at all orders. The flow of the effective parameters is controlled thanks to Ward identities and a careful analysis of the discrete lattice symmetry properties of the model. We show that the Fermi velocity increases up to the speed of light and Lorentz invariance spontaneously emerges in the infrared. The interaction produces critical exponents in the response functions; this removes the degeneracy present in the non interacting case and allows us to identify the dominant excitations. Finally, we add mass terms to the Hamiltonian and derive by a variational argument the correspondent gap equations, which have an anomalous non-BCS form, due to the non trivial effects of the interaction. © 2011 Elsevier Inc. Source

Matera M.G.,The Second University of Naples | Page C.,Kings College London | Cazzola M.,University of Rome Tor Vergata
Expert Opinion on Investigational Drugs | Year: 2014

Introduction: PDE inhibitors could be useful in the treatment of asthma because of their bronchodilator and/or anti-inflammatory activities. Recently, some selective PDE3, PDE4 and PDE3/4 inhibitors have been shown to have beneficial effects in patients with asthma suggesting that such drugs may offer novel therapeutic options for the treatment of this disease.Areas covered: The authors describe the main PDE families that could be involved in asthma as well as the PDE inhibitors that have been evaluated for the treatment of asthma.Expert opinion: Although the potential therapeutic utility of PDE inhibitors has been demonstrated in various animal models of asthma, their clinical efficacy have been restricted by the dose-limiting side effects; no PDE inhibitor has yet been approved for the treatment of patients with asthma. Although new PDE inhibitors have been synthesised, most data are from cellular and tissue-level studies with human trials still on the horizon. Apparently, only CHF 6001, an inhaled PDE4 inhibitor, and RPL554, a dual PDE3/4 inhibitor, are still under clinical development. Further data from these new drugs are eagerly anticipated to better understand where these drugs might stand in the future treatment of asthma. © 2014 Informa UK, Ltd. Source

Stankovski T.,Lancaster University | Duggento A.,University of Rome Tor Vergata | McClintock P.V.E.,Lancaster University | Stefanovska A.,Lancaster University
Physical Review Letters | Year: 2012

A new method is introduced for analysis of interactions between time-dependent coupled oscillators, based on the signals they generate. It distinguishes unsynchronized dynamics from noise-induced phase slips and enables the evolution of the coupling functions and other parameters to be followed. It is based on phase dynamics, with Bayesian inference of the time-evolving parameters achieved by shaping the prior densities to incorporate knowledge of previous samples. The method is tested numerically and applied to reveal and quantify the time-varying nature of cardiorespiratory interactions. © 2012 American Physical Society. Source

Stanev Y.S.,University of Rome Tor Vergata
Nuclear Physics B | Year: 2012

We derive a generating function for all the 3-point functions of higher spin conserved currents in four dimensional conformal field theory. The resulting expressions have a rather surprising factorized form which suggests that they can all be realized by currents built from free massless fields of arbitrary (half-)integer spin . s. This property is however not necessarily true also for the higher-point functions. As an illustration we analyze the general 4-point function of conserved abelian . U(1) currents of scale dimension equal to three and find that apart from the two free field realizations there is a unique possible function which may correspond to an interacting theory. Although this function passes several non-trivial consistency tests, it remains an open challenging problem whether it can be actually realized in an interacting CFT. © 2012 Elsevier B.V. Source

Curatolo P.,University of Rome Tor Vergata
Pediatric Neurology | Year: 2015

Background Tuberous sclerosis complex is a multiorgan disease resulting from a mutation of one of two TSC genes. The two gene products form a functional complex that regulates the mTOR signaling pathway (mTOR initially represented mammalian target of rapamycin, but increasingly the term mechanistic target of rapamycin is used to reflect the ubiquitous occurrence of mTOR). Epilepsy is the most common neurological symptom of tuberous sclerosis complex, occurring in 80% to 90% of affected individuals over the course of their lifetimes and causing significant morbidity and mortality. The mechanistic target of rapamycin (mTOR) signaling pathway is intricately involved in multiple cellular functions - including protein synthesis, cell growth and proliferation, and synaptic plasticity - which may influence neuronal excitability and precipitate epileptogenesis. Recent preclinical and clinical studies have increased interest in the potential role of mTOR inhibitors for the treatment of tuberous sclerosis complex-related epilepsy. Methods Medline and PubMed database searches were used to identify relevant studies and other information on tuberous sclerosis complex-related epilepsies, the mTOR pathway, and current advances in treatment approaches. Results Although current management strategies that provide symptomatic relief are effective at reducing the frequency of seizures in individuals with tuberous sclerosis complex, there is further room for the exploration of therapies that directly address hyperactive mTOR signaling - the underlying etiology of the disease. The role of the antiepileptic effect of mTOR inhibition was first demonstrated in knockout TSC1 mouse models. Additionally, several case studies demonstrated a positive effect on seizure frequency and severity in patients with pharmacoresistant epilepsy. In a phase 1/2 clinical trial with 28 patients, clinically relevant reduction in overall seizure frequency was documented in individuals treated with the mTOR inhibitor everolimus. In a phase 3 trial evaluating the role of everolimus in subependymal giant cell astrocytoma, seizures were a secondary end point. Because the median seizure frequency was zero in this study, the analysis was inconclusive. Conclusion Various preclinical models provide substantial evidence for the role of mTOR inhibition in the treatment of epilepsy in individuals with tuberous sclerosis complex. Preliminary clinical studies provide supportive evidence for a role of mTOR inhibition in the management of tuberous sclerosis complex-associated epilepsy and pave the way for new randomized placebo-controlled studies. This article reviews current treatment recommendations for the management of tuberous sclerosis complex-associated epilepsy as well as the rationale and evidence to support the use of mTOR inhibitors. © 2015 Elsevier Inc. All rights reserved. Source

Spallone V.,University of Rome Tor Vergata
Current Diabetes Reports | Year: 2012

The treatment of painful diabetic polyneuropathy (PDPN) remains a major challenge. A number of reasons have made the guidelines on PDPN management of particular interest, including its high prevalence, health and socioeconomic impact, interdisciplinary nature and the need for updated evidence-based information to refine patienttailored treatment by weighing up the risks of each treatment against its proven benefits, as well as optimizing the use of all available resources. The various guidelines on the management of neuropathic pain developed so far contain some differences in their work methodology and results. Some variations in the recommendations are to be expected but could be disorienting and confusing for stakeholders. In this review, a critical evaluation of the more recent guidelines on the management of PDPN is provided together with highlights on points of agreement and disagreement as well as insights into their clinical aspects. © Springer Science+Business Media, LLC 2012. Source

Ibeas A.,University of Cantabria | Cordera R.,ETRA Norte S.A. | Dell'Olio L.,University of Cantabria | Coppola P.,University of Rome Tor Vergata
Transportation Research Part A: Policy and Practice | Year: 2013

The use of Mul