42 research outputs found
High availability using virtualization
No full textHigh availability has always been one of the main problems for a data center. Till
now high availability was achieved by host per host redundancy, a highly expensive method in
terms of hardware and human costs. A new approach to the problem can be offered by
virtualization. Using virtualization, it is possible to achieve a redundancy system for all the
services running on a data center. This new approach to high availability allows the running
virtual machines to be distributed over a small number of servers, by exploiting the features of
the virtualization layer: start, stop and move virtual machines between physical hosts. The 3RC
system is based on a finite state machine, providing the possibility to restart each virtual
machine over any physical host, or reinstall it from scratch. A complete infrastructure has been
developed to install operating system and middleware in a few minutes. To virtualize the main
servers of a data center, a new procedure has been developed to migrate physical to virtual
hosts. The whole Grid data center SNS-PISA is running at the moment in virtual environment
under the high availability system
Oxidative stress, isoprostanes and hepatic fibrosis
No full textAn introduction to oxidative stress enlightening the spreading of interest in lipid peroxidation in the 60's and in the identification of cytotoxic aldehydes originating from it is given. The discovery of F2-isoprostanes as specific markers of oxidative stress is described. Isoprostanes are also agonists of important biological effects. Since a relationship between oxidative stress and collagen hyperproduction has been previously suggested, and since lipid peroxidation products (aldehydes) have been proposed as possible mediators of liver fibrosis, we investigated whether collagen synthesis is induced by F2-isoprostanes, which can posses receptors for signal transduction pathways. In a rat model of carbon tetrachloride-induced hepatic fibrosis, plasma isoprostanes were markedly elevated for the entire experimental period and hepatic collagen content was also increased. Moreover, when hepatic stellate cells (HSC) isolated from normal livers were cultured up to activation and then treated with F2-isoprostanes (8-epi-PGF2α) in the concentration range found in the in vivo studies (10-9 to 10-8 M), a striking increase in DNA synthesis, in cell proliferation and in collagen synthesis was observed. F2-isoprostanes also increased the production of transforming growth factor-ß1 by U937 cells, assumed as a model of Kupffer cells or liver macrophages. The hypothesis that F2-isoprostanes generated by lipid peroxidation in hepatocytes mediate HSC proliferation and collagen hyperproduction, seen in this experimental hepatic fibrosis, was reinforced by the demonstration, by using immunoblot analysis, that isoprostane receptors identical or analogous to those for thromboxane A2 (TxA2r) are present in HSC. Immunocytochemical studies showed the major localization of TxA2r in the perinuclear site and its colocalization with α-smooth muscle actin
Modulazione -glutamil transpeptidasi-dipendente delle attività collagenolitiche in cellule di melanoma Me665/2 a diverso potenziale invasivo
No full textHPC on the Grid: the Theophys experience
No full textThe Grid Virtual Organization (VO)
“Theophys”, associated to the INFN (Istituto
Nazionale di Fisica Nucleare), is a theoretical
physics community with various computational
demands, spreading from serial, SMP, MPI and
hybrid jobs. That has led, in the past 20 years, towards
the use of the Grid infrastructure for serial
jobs, while the execution of multi-threaded, MPI
and hybrid jobs has been performed in several
small-medium size clusters installed in different
sites, with access through standard local submission
methods. This work analyzes the support for
parallel jobs in the scientific Grid middlewares,
then describes how the community unified the
management of most of its computational need
(serial and parallel ones) using the Grid through
the development of a specific project which integrates
serial e parallel resources in a common
Grid based framework. A centralized national
cluster is deployed inside this framework, providing
“Wholenodes” reservations, CPU affinity,
and other new features supporting our High Per-
formance Computing (HPC) applications in the
Grid environment. Examples of the cluster performance
for relevant parallel applications in theoretical
physics are reported, focusing on the
different kinds of parallel jobs that can be served
by the new features introduced in the Grid
Glycosyl-curcuminoids as potential new chelating agents in iron overload chelation therapy
No full textThe iron(III) chelating ability of some glycosyl derivatives of curcuminoids is tested by means of UV, potentiometric and NMR studies. The pK(a) of the ligands and the stability constants of their Fe3+ and Ga3+ complexes are evaluated by UV spectroscopy. The only metal binding site of the ligand is the beta-dioxo moiety; the glycosyl moiety does not interact with the metal ion at acidic pH values but it helps to stabilise metal/ligand (1:2) complexes by means of hydrophilic interactions. By comparing the pFe(3+) of our ligands with those reported for other chelating agents we suggest using these molecules as pro-drugs in iron overload treatment. Some of the more water-soluble derivatives are also tested for their antioxidant properties in vitro in biological systems and proved to act as free-radical scavengers inhibiting the iron redox cycle, ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Levels of folic acid in plasma and in blood cells of colorectal cancer patients
No full textThe levels of folic acid have been determined by radioimmunological method in the plasma and in the red blood cells of normal subjects and colorectal cancer patients. A decrease was evident both in the plasma and erythrocytes of cancer patients. The possible reasons and applications of this observation are discusse
Ethanol-induced oxidative stress: basic knowledge
No full textAfter a general introduction, the main pathways of ethanol metabolism (alcohol dehydrogenase, catalase, coupling of catalase with NADPH oxidase and microsomal ethanol-oxidizing system) are shortly reviewed. The cytochrome P(450) isoform (CYP2E1) specifically involved in ethanol oxidation is discussed. The acetaldehyde metabolism and the shift of the NAD/NADH ratio in the cellular environment (reductive stress) are stressed. The toxic effects of acetaldehyde are mentioned. The ethanol-induced oxidative stress: the increased MDA formation by incubated liver preparations, the absorption of conjugated dienes in mitochondrial and microsomal lipids and the decrease in the most unsaturated fatty acids in liver cell membranes are discussed. The formation of carbon-centered (1-hydroxyethyl) and oxygen-centered (hydroxyl) radicals during the metabolism of ethanol is considered: the generation of hydroxyethyl radicals, which occurs likely during the process of univalent reduction of dioxygen, is highlighted and is carried out by ferric cytochrome P(450) oxy-complex (P(450)-Fe(3+)O(2) (.-)) formed during the reduction of heme-oxygen. The ethanol-induced lipid peroxidation has been evaluated, and it has been shown that plasma F(2)-isoprostanes are increased in ethanol toxicity
