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Search Results: 1 - 10 of 2099 matches for " Ilaria Russo "
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A Plane Wave Virtual Element Method for the Helmholtz Problem
Ilaria Perugia,Paola Pietra,Alessandro Russo
Mathematics , 2015,
Abstract: We introduce and analyze a virtual element method (VEM) for the Helmholtz problem with approximating spaces made of products of low order VEM functions and plane waves. We restrict ourselves to the 2D Helmholtz equation with impedance boundary conditions on the whole domain boundary. The main ingredients of the plane wave VEM scheme are: i) a low frequency space made of VEM functions, whose basis functions are not explicitly computed in the element interiors; ii) a proper local projection operator onto the high-frequency space, made of plane waves; iii) an approximate stabilization term. A convergence result for the h-version of the method is proved, and numerical results testing its performance on general polygonal meshes are presented.
Heart rate variability analysis in postural orthostatic tachycardia syndrome: a case report
Vincenzo Russo,Ilaria De Crescenzo,Ernesto Ammendola,Carolina Pagano
Heart International , 2010, DOI: 10.4081/hi.2006.126
Abstract: The authors present a case of 36 year old male patient with idiopathic postural orthostatic tachycardia syndrome (POTS) diagnosed during head-up tilt testing. Power spectral analysis of heart rate variability (HRV) during the tilt test revealed that the ratio of low and high frequency powers (LF/HF) increased with the onset of orthostatic intolerance. This analysis confirmed in our patient a strong activation in sympathetic tone.
Butyrate Attenuates Lipopolysaccharide-Induced Inflammation in Intestinal Cells and Crohn's Mucosa through Modulation of Antioxidant Defense Machinery
Ilaria Russo, Alessandro Luciani, Paola De Cicco, Edoardo Troncone, Carolina Ciacci
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032841
Abstract: Oxidative stress plays an important role in the pathogenesis of inflammatory bowel disease (IBD), including Crohn's disease (CrD). High levels of Reactive Oxygen Species (ROS) induce the activation of the redox-sensitive nuclear transcription factor kappa-B (NF-κB), which in turn triggers the inflammatory mediators. Butyrate decreases pro-inflammatory cytokine expression by the lamina propria mononuclear cells in CrD patients via inhibition of NF-κB activation, but how it reduces inflammation is still unclear. We suggest that butyrate controls ROS mediated NF-κB activation and thus mucosal inflammation in intestinal epithelial cells and in CrD colonic mucosa by triggering intracellular antioxidant defense systems. Intestinal epithelial Caco-2 cells and colonic mucosa from 14 patients with CrD and 12 controls were challenged with or without lipopolysaccaride from Escherichia Coli (EC-LPS) in presence or absence of butyrate for 4 and 24 h. The effects of butyrate on oxidative stress, p42/44 MAP kinase phosphorylation, p65-NF-κB activation and mucosal inflammation were investigated by real time PCR, western blot and confocal microscopy. Our results suggest that EC-LPS challenge induces a decrease in Gluthation-S-Transferase-alpha (GSTA1/A2) mRNA levels, protein expression and catalytic activity; enhanced levels of ROS induced by EC-LPS challenge mediates p65-NF-κB activation and inflammatory response in Caco-2 cells and in CrD colonic mucosa. Furthermore butyrate treatment was seen to restore GSTA1/A2 mRNA levels, protein expression and catalytic activity and to control NF-κB activation, COX-2, ICAM-1 and the release of pro-inflammatory cytokine. In conclusion, butyrate rescues the redox machinery and controls the intracellular ROS balance thus switching off EC-LPS induced inflammatory response in intestinal epithelial cells and in CrD colonic mucosa.
Selection of Candidate Housekeeping Genes for Normalization in Human Postmortem Brain Samples
Ilaria Penna,Serena Vella,Arianna Gigoni,Claudio Russo,Ranieri Cancedda,Aldo Pagano
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12095461
Abstract: The most frequently used technique to study the expression profile of genes involved in common neurological disorders is quantitative real-time RT-PCR, which allows the indirect detection of very low amounts of selected mRNAs in tissue samples. Expression analysis by RT-qPCR requires an appropriate normalization to the expression level of genes characterized by a stable, constitutive transcription. However, the identification of a gene transcribed at a very stable level is difficult if not impossible, since significant fluctuations of the level of mRNA synthesis often accompanies changes of cell behavior. The aim of this study is to identify the most stable genes in postmortem human brain samples of patients affected by Alzheimer’s disease (AD) suitable as reference genes. The experiments analyzed 12 commonly used reference genes in brain samples from eight individuals with AD and seven controls. After a careful analysis of the results calculated by geNorm and NormFinder algorithms, we found that CYC1 and EIF4A2 are the best reference genes. We remark on the importance of the determination of the best reference genes for each sample to be analyzed and suggest a practical combination of reference genes to be used in the analysis of human postmortem samples.
A Mechanochemical Approach to Porous Silicon Nanoparticles Fabrication
Luigi Russo,Francesco Colangelo,Raffaele Cioffi,Ilaria Rea,Luca De Stefano
Materials , 2011, DOI: 10.3390/ma4061023
Abstract: Porous silicon samples have been reduced in nanometric particles by a well known industrial mechanical process, the ball grinding in a planetary mill; the process has been extended to crystalline silicon for comparison purposes. The silicon nanoparticles have been studied by X-ray diffraction, infrared spectroscopy, gas porosimetry and transmission electron microscopy. We have estimated crystallites size from about 50 nm for silicon to 12 nm for porous silicon. The specific surface area of the powders analyzed ranges between 100 m 2/g to 29 m 2/g depending on the milling time, ranging from 1 to 20 h. Electron microscopy confirms the nanometric size of the particles and reveals a porous structure in the powders obtained by porous silicon samples which has been preserved by the fabrication conditions. Chemical functionalization during the milling process by a siloxane compound has also been demonstrated.
A Novel Chemotaxis Assay in 3-D Collagen Gels by Time-Lapse Microscopy
Angela Vasaturo, Sergio Caserta, Ilaria Russo, Valentina Preziosi, Carolina Ciacci, Stefano Guido
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0052251
Abstract: The directional cell response to chemical gradients, referred to as chemotaxis, plays an important role in physiological and pathological processes including development, immune response and tumor cell invasion. Despite such implications, chemotaxis remains a challenging process to study under physiologically-relevant conditions in-vitro, mainly due to difficulties in generating a well characterized and sustained gradient in substrata mimicking the in-vivo environment while allowing dynamic cell imaging. Here, we describe a novel chemotaxis assay in 3D collagen gels, based on a reusable direct-viewing chamber in which a chemoattractant gradient is generated by diffusion through a porous membrane. The diffusion process has been analysed by monitoring the concentration of FITC-labelled dextran through epifluorescence microscopy and by comparing experimental data with theoretical and numerical predictions based on Fick's law. Cell migration towards chemoattractant gradients has been followed by time-lapse microscopy and quantified by cell tracking based on image analysis techniques. The results are expressed in terms of chemotactic index (I) and average cell velocity. The assay has been tested by comparing the migration of human neutrophils in isotropic conditions and in the presence of an Interleukin-8 (IL-8) gradient. In the absence of IL-8 stimulation, 80% of the cells showed a velocity ranging from 0 to 1 μm/min. However, in the presence of an IL-8 gradient, 60% of the cells showed an increase in velocity reaching values between 2 and 7 μm/min. Furthermore, after IL-8 addition, I increased from 0 to 0.25 and 0.25 to 0.5, respectively, for the two donors examined. These data indicate a pronounced directional migration of neutrophils towards the IL-8 gradient in 3D collagen matrix. The chemotaxis assay described here can be adapted to other cell types and may serve as a physiologically relevant method to study the directed locomotion of cells in a 3D environment in response to different chemoattractants.
PfeIK1, a eukaryotic initiation factor 2α kinase of the human malaria parasite Plasmodium falciparum, regulates stress-response to amino-acid starvation
Clare Fennell, Shalon Babbitt, Ilaria Russo, Jonathan Wilkes, Lisa Ranford-Cartwright, Daniel E Goldberg, Christian Doerig
Malaria Journal , 2009, DOI: 10.1186/1475-2875-8-99
Abstract: The impact of starvation on the phosphorylation state of PfeIF2α was examined. Bioinformatic methods were used to identify plasmodial eIF2α kinases. The activity of one of these, PfeIK1, was investigated using recombinant protein with non-physiological substrates and recombinant PfeIF2α. Reverse genetic techniques were used to disrupt the pfeik1 gene.The data demonstrate that the Plasmodium falciparum eIF2α orthologue is phosphorylated in response to starvation, and provide bioinformatic evidence for the presence of three eIF2α kinases in P. falciparum, only one of which (PfPK4) had been described previously. Evidence is provided that one of the novel eIF2α kinases, PfeIK1, is able to phosphorylate the P. falciparum eIF2α orthologue in vitro. PfeIK1 is not required for asexual or sexual development of the parasite, as shown by the ability of pfeik1- parasites to develop into sporozoites. However, eIF2α phosphorylation in response to starvation is abolished in pfeik1- asexual parasitesThis study strongly suggests that a mechanism for versatile regulation of translation by several kinases with a similar catalytic domain but distinct regulatory domains, is conserved in P. falciparum.Human malaria is caused by infection with intracellular protozoan parasites of the genus Plasmodium that are transmitted by Anopheles mosquitoes. Of four species that infect humans, Plasmodium falciparum is responsible for the most virulent form of the disease. The transition from one stage of the life cycle to the next must be tightly regulated, to ensure proliferation and differentiation occur when and where appropriate; this is undoubtedly linked to differential gene expression. Analysis of the P. falciparum transcriptome during the erythrocytic asexual cycle reveals an ordered cascade of gene expression [1], and the various developmental stages display distinct transcriptomes; how this is orchestrated remains obscure. Initial investigation of the P. falciparum genome revealed a paucity
Accurate Tools for Analyzing the Behavior of Impulse Noise Reduction Filters in Color Images  [PDF]
Fabrizio Russo
Journal of Signal and Information Processing (JSIP) , 2013, DOI: 10.4236/jsip.2013.41005
Abstract:

Effective cancellation of noise and preservation of color/structural information are features of paramount importance for any filter devoted to impulse noise removal in color images. In this paper novel full-reference tools for analyzing the behavior of this family of filters are presented. The proposed approach is based on the classification of color errors into two main classes that separately take into account the inaccuracy in removing noise pulses and the filtering distortion. The distortion errors are then classified into two subclasses for a deeper analysis of the filtering behavior. Computer simulations show that the proposed method gives more accurate results than using other measures of filtering performance in the literature. Furthermore, the method can easily yield the spatial location of the different filtering features in the image.

Using Rapid Prototyping Data to Enhance a Knowledge-Based Framework for Product Redesign  [PDF]
Stefano FILIPPI, Ilaria CRISTOFOLINI
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.21001
Abstract: The particular characteristics of Rapid Prototyping technologies, both in terms of constrains and opportunities, often require the reconfiguration of the product model to obtain the best compliance with the product functionalities and performances. Within this field of research, a knowledge-based tool named Design GuideLines Collaborative Framework (DGLs-CF) was developed to support both the designers defining the product consistently with the manufacturing technologies and the manufacturers defining the building setup consistently with the product requirements. Present work is focused on enhancing the DGLs-CF knowledge base and on updating the DGLs-CF knowledge management by using the information gathered on some RP technologies. The added-value of this research is represented by an improvement in the Redesign/Reconfig- uration Package, the final result of the DGLs-CF adoption. This is a list of actions to be performed on the product model and on the process parameters to avoid the limitations of the technology and to exploit at best its opportunities.
Historic Centers Restoration and Ancient Buildings Energetic Efficiency Improvement  [PDF]
Nicola Santopuoli, Ilaria Pecoraro
Journal of Building Construction and Planning Research (JBCPR) , 2014, DOI: 10.4236/jbcpr.2014.23019
Abstract: The historical center is a part of the city with specific environmental, architectural and historical values, which emerges from the urban fabric structural continuity. This complex reality requires a comprehensive understanding to determinate the most proper ways to carry out functional transformations and system adaptations, with respect to historical buildings values. Each building must obtain those proper improvements and functional adjustments, also in terms of technology and energetic efficiency. The achievements of a complex interdisciplinary research project on Ceglie Messapica historical center (BR, Italy) are explained. They lead to guidelines for mulation for the historical buildings’ critical conservative restoration.
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