Quantifying Timing Leaks and Cost Optimisation

We develop a new notion of security against timing attacks where the attacker is able to simultaneously observe the execution time of a program and the probability of the values of low variables. We then show how to measure the security of a program with respect to this notion via a computable estimate of the timing leakage and use this estimate for cost optimisation.Comment: 16 pages, 2 figures, 4 tables. A shorter version is included in the proceedings of ICICS'08 - 10th International Conference on Information and Communications Security, 20-22 October, 2008 Birmingham, U

Information Security as Strategic (In)effectivity

Security of information flow is commonly understood as preventing any information leakage, regardless of how grave or harmless consequences the leakage can have. In this work, we suggest that information security is not a goal in itself, but rather a means of preventing potential attackers from compromising the correct behavior of the system. To formalize this, we first show how two information flows can be compared by looking at the adversary's ability to harm the system. Then, we propose that the information flow in a system is effectively information-secure if it does not allow for more harm than its idealized variant based on the classical notion of noninterference

Light hadrons with improved staggered quarks: approaching the continuum limit

We have extended our program of QCD simulations with an improved Kogut-Susskind quark action to a smaller lattice spacing, approximately 0.09 fm. Also, the simulations with a approximately 0.12 fm have been extended to smaller quark masses. In this paper we describe the new simulations and computations of the static quark potential and light hadron spectrum. These results give information about the remaining dependences on the lattice spacing. We examine the dependence of computed quantities on the spatial size of the lattice, on the numerical precision in the computations, and on the step size used in the numerical integrations. We examine the effects of autocorrelations in "simulation time" on the potential and spectrum. We see effects of decays, or coupling to two-meson states, in the 0++, 1+, and 0- meson propagators, and we make a preliminary mass computation for a radially excited 0- meson.Comment: 43 pages, 16 figure

Transglutaminase-catalyzed preparation of chitosan-ovalbumin films

Microbial transglutaminase was employed as catalyst for preparing chitosan–ovalbumin films. The films showed low solubility at a wide range of pH and underwent to a good enzymatic hydrolysis with trypsin. The degree of swelling was reduced and the mechanical resistance of the chitosan–ovalbumin films increased from 24 to 35MPa after enzymatic treatment with transglutaminase. The barrier efficiency toward water vapour was slightly improved for the films prepared by transglutaminase-mediated cross-linking

Consanguinity and polygenic diseases: a model for antibody deficiencies

Primary immunodeficiencies represent a heterogeneous group of disorders of the immune system, predisposing to various types of infections. Among them, common variable immunodeficiency is the most common symptomatic antibody deficiency. It includes several different forms characterized by defects in the terminal stage of B lymphocyte differentiation, leading to markedly reduced immunoglobulin serum levels and increased susceptibility to bacterial infections. The clinical phenotype is complex, including autoimmunity, granulomatous inflammation, lymphoproliferative disorders and malignancies. Rare autosomal recessive mutations in a number of single genes have recently been reported. However, the underlying genetic defects remain unknown in the majority of cases. In order to seek new genes responsible for the disease, we studied a consanguineous Italian family through exome sequencing combined with homozygosity mapping. Six missense homozygous variants passed our filtering selection and at least two of them were associated with some aspects of the pathological phenotype. Our data remark the complexity of immune system disorders and emphasize the difficulty to understand the significance of genetic results and their correlation with the disease phenotype

Putrescine-polysaccharide conjugate as transglutaminase substrates and their possible use in producing crosslinked films

Putrescine (1,4-diaminobutane) was covalently linked to alginate and low-methoxyl pectin to synthesize new aminated polysaccharides. Both putrescine-pectin and -alginate conjugates, although the latter at higher concentrations, were found to be able to act as effective acyl acceptor transglutaminase substrates in vitro using both dimethylated casein and soy flour proteins as acyl donors. Monodansylcadaverine, a well known acyl acceptor transglutaminase substrate, dose-dependently counteracted the covalent binding of the aminated polysaccharides to the proteins. Putrescine-pectin conjugate was also tested to prepare, in combination with soy flour proteins, edible films in the presence of purified microbial transglutaminase. Characterization of the enzymatically crosslinked films showed a significant decreased water vapor permeability, with respect to the ones obtained with non-aminated pectin in the presence of transglutaminase, as well as improved mechanical properties, such as high extensibility. Possible biotechnological applications of hydrocolloid films containing putrescine-polysaccharide derivatives enzymatically crosslinked to proteins were suggested

Transglutaminase-catalyzed site-specific glycosidation of catalase with aminated dextran

An enzymatic approach, based on a transglutaminase-catalyzed coupling reaction, was investigated to modify bovine liver catalase with an end-group aminated dextran derivative. We demonstrated that catalase activity increased after enzymatic glycosidation and that the conjugate was 3.8-fold more stable to thermal inactivation at 55 ◦C and 2-fold more resistant to proteolytic degradation by trypsin. Moreover, the transglutaminase-mediated modification also improved the pharmacokinetics behavior of catalase, increasing 2.5-fold its plasma half-life time and reducing 3-fold the total clearance after its i.v. administration in rats

Development of a biosensor for copper detection in aqueous solutions using an Anemonia sulcata recombinant GFP

Fluorescent proteins from marine organisms represent potential candidates for biosensor development. In this paper, we described the isolation of a native green fluorescent protein from Anemonia sulcata and the cloning and purification of its equivalent as a recombinant protein in Escherichia coli. Furthermore, the spectroscopic behaviours of the native and recombinant GFPs were investigated as a function of Cu2+, Cd2+, Pb 2+ and Ni2+ concentration. Our results suggest the high selectivity of both proteins at copper than the other metals and, for the recombinant protein, a great sensitivity at a very low concentration (0.1-1 μM). Moreover, starting from these data, using the combination of molecular biology techniques and optical setup, we developed a device for the detection of Cu2+ in water solutions. The quenching effect detected with the device showed that the relative attenuation of the signal (0.46±0.02 AU) was slightly larger than the data measured by fluorescence spectra (0.65±0.03 AU). The good sensitivity in the span of two orders of the magnitude of Cu2+ concentration, the fact that the instrument is made up of low-cost and sturdy parts and the selective quenching of rAsGFP to copper ions make this setup suited as a low cost, on-the-field, copper ion-specific biosensor. © 2013 Springer Science+Business Media