Two classes of real numbers and formal power series: quasi algebraic objects

Maurizio Citterio and Rodolfo Talamo, "Two classes of real numbers and formal power series: quasi algebraic objects", in: Rendiconti dell’Istituto di Matematica dell’Università di Trieste. An International Journal of Mathematics, 46 (2014), pp.181-201Motivated by the endeavour to extend to the algebraic irrationals the notion of best rational approximation to a given real number, we define the concept of quasi algebraic number and prove some results related to it. We apply these results to the study of the Schroeder functional equation with quasi algebraic parameter. The main definitions can be transposed to the field of formal Laurent series over a finite field. In this respect we prove that every badly approximable series is quasi algebraic

Interleaving Command Sequences: a Threat to Secure Smartcard Interoperability

The increasingly widespread use of smartcards for a variety of sensitive applications, including digital signatures, creates the need to ensure and possibly certify the secure interoperability of these devices. Standard certification criteria, in particular the Common Criteria, define security requirements but do not sufficiently address the problem of interoperability. Here we consider the interoperability problem which arises when various applications interact with different smartcards through a middleware. In such a situation it is possible that a smartcard of type S receives commands that were supposed to be executed on a different smartcard of type S'. Such "external commands" can interleave with the commands that were supposed to be executed on S. We experimentally demonstrate this problem with a Common Criteria certified digital signature process on a commercially available smartcard. Importantly, in some of these cases the digital signature processes terminate without generating an error message or warning to the user.Comment: 6 pages; published in the 10th WSEAS International Conference on Information Security and Privacy (ISP 2011

A pointer-free data structure for merging heaps and min-max heaps

AbstractIn this paper a data structure for the representation of mergeable heaps and min-max heaps without using pointers is introduced. The supported operations are: Insert, DeleteMax, DeleteMin, FindMax, FindMin, Merge, NewHeap, DeleteHeap. The structure is analyzed in terms of amortized time complexity, resulting in a O(1) amortized time for each operation except for Insert, for which a O(lg n) bound holds

Metal free graphene oxide (GO) nanosheets and pristine-single wall carbon nanotubes (p-SWCNTs) biocompatibility investigation: a comparative study in different human cell lines

The in vitro biocompatibility of Graphene Oxide (GO) nanosheets, which were obtained by the electrochemical exfoliation of graphite electrodes in an electrolytic bath containing salts, was compared with the pristine Single Wall Carbon Nanotubes (p-SWCNTs) under the same experimental conditions in different human cell lines. The cells were treated with different concentrations of GO and SWCNTs for up to 48 h. GO did not induce any significant morphological or functional modifications (demonstrating a high biocompatibility), while SWNCTs were toxic at any concentration used after a few hours of treatment. The cell viability or cytotoxicity were detected by the trypan blue assay and the lactate dehydrogenase LDH quantitative enzymatic test. The Confocal Laser Scanning Microscopy (CLSM) and transmission electron microscopy (TEM) analysis demonstrated the uptake and internalization of GO sheets into cells, which was localized mainly in the cytoplasm. Different results were observed in the same cell lines treated with p-SWCNTs. TEM and CLSM (Confocal Laser Scanning Microscopy) showed that the p-SWCNTs induced vacuolization in the cytoplasm, disruption of cellular architecture and damage to the nuclei. The most important result of this study is our finding of a higher GO biocompatibility compared to the p-SWCNTs in the same cell lines. This means that GO nanosheets, which are obtained by the electrochemical exfoliation of a graphite-based electrode (carried out in saline solutions or other physiological working media) could represent an eligible nanocarrier for drug delivery, gene transfection and molecular cell imaging tests

Multiple myeloma presenting as CEA-producing rectal cancer

We report the case of a 57-year-old patient with multiple myeloma, characterized by extramedullary involvement of the rectum at presentation. Malignant plasma cells were found to produce carcinoembryonic antigen (CEA), a tumor antigen more commonly associated with rectal adenocarcinomas

Unregulated Custody Transfers: Why the Practice of Rehoming Should Be Considered a Form of Illegal Adoption and Human Trafficking

In this work, the authors prepared and characterized two different graphene oxides: one chemically synthesized (GO sample) and the other one electrochemically synthesized (GO(LiCl)). Both samples were fully characterized with atomic force microscopy (AFM), Raman and Fourier transform infrared (FTIR) spectroscopies, X-ray photo electron spectroscopy (XPS), thermal analysis (TG/DTA), and Z-potential. The antibacterial properties of both graphene oxides were studied using Gram-negative Escherichia coli ATCC 25922 and Gram-positive Staphylococcus aureus ATCC 25923 by spectrophotometer and viable cell count as indirect and direct methods, respectively. Results demonstrated that the GO(LiCl) exhibited a significant antibacterial activity compared to GO that showed a bacteriostatic effect on both pathogens. Electron microscopy analysis confirmed the antibacterial effects of both graphene oxides toward the pathogens, especially working at 80 μg/mL, for 24 h. Additional studies were also performed and both GO samples were not cytotoxic at 2 μg/mL toward neuroblastoma cells. Moreover, 2 μg of GO was suitable to carry the minimum effective dose (5.74 ng/mL) of kinase inhibitor S29 (1-(2-chloro-2-(4-chlorophenyl)ethyl)-N-(4-fluorobenzyl)-1H-pyrazolo[3,4-d] pyrimidin-4-amine), providing negligible side effects related to the S29 treatment (this latter being specifically active on the neuroblastoma cell lines (SK-N-BE(2)))