Purification and preliminary structural characterization by NMR spectroscopy of the "HoLaMa" DNA polymerase

HoLaMa is a Klenow sub-fragment lacking the 3’-5’ exonuclease domain, whose gene codes for residues 515-928 of Escherichia coli DNA polymerase I. The enzyme was designed in a previous study starting from different Klenow enzymes, with the aim of studying a mini-DNA polymerase with NMR spectroscopy. In the present work, we studied a new purification protocol for the production of HoLaMa in order to obtain an appropriate quantity for NMR analysis. We tested three different purification procedure and at the end, we collected 5.8 mg of HoLaMa (Volume 1.8 mL, concentration 67 μM). After the purification, we started the study of HoLaMa by NMR spectroscopy, focusing on the nature of enzyme-substrate interactions and studying the kinetics of the reaction. Our preliminary studies were designed to understand the characteristic NMR signals of HoLaMa under different conditions of temperature and buffer; finally, we also focused our analysis on the interactions between protein, DNA and nucleotides

“Algorithms in Multi-Objective Optimization”: Foreword by the Guest Editor

Many real-world optimization problems typically involve multiple (conflicting) objectives [...

Flash-memories in Space Applications: Trends and Challenges

Nowadays space applications are provided with a processing power absolutely overcoming the one available just a few years ago. Typical mission-critical space system applications include also the issue of solid-state recorder(s). Flash-memories are nonvolatile, shock-resistant and power-economic, but in turn have different drawbacks. A solid-state recorder for space applications should satisfy many different constraints especially because of the issues related to radiations: proper countermeasures are needed, together with EDAC and testing techniques in order to improve the dependability of the whole system. Different and quite often contrasting dimensions need to be explored during the design of a flash-memory based solid- state recorder. In particular, we shall explore the most important flash-memory design dimensions and trade-offs to tackle during the design of flash-based hard disks for space application

FLARE: A design environment for FLASH-based space applications

Designing a mass-memory device (i.e., a solid-state recorder) is one of the typical issues of mission-critical space system applications. Flash-memories could be used for this goal: a huge number of parameters and trade-offs need to be explored. Flash-memories are nonvolatile, shock-resistant and power-economic, but in turn have different drawback: e.g., their cost is higher than normal hard disk and the number of erasure cycles is bounded. Moreover space environment presents various issues especially because of radiations: different and quite often contrasting dimensions need to be explored during the design of a flash-memory based solid-state recorder. No systematic approach has so far been proposed to consider them all as a whole: as a consequence a novel design environment currently under development is aimed at supporting the design of flash-based mass-memory device for space application

H-magnetic resonance spectroscopy. diagnostic tool in recurrent headache in systemic lupus erythematosus. a case report

We describe serial MR-spectroscopy studies in a patient with systemic lupus erythematosus and headache. We used MR-spectroscopy to monitor disease activity during periods with and without headache. MR-spectroscopy investigates metabolic alterations and was used to explore the pathophysiological mechanism involved in the complications of systemic lupus erythematosus. Our patient underwent serial conventional MRI and MR-spectroscopy at times of controlled and uncontrolled headache, with or without visual aura. MR-spectroscopy showed an increase in the choline/creatine ratio in thalamus and posterior white matter only during periods of uncontrolled headache with visual aura. Conventional MRI scans were normal at all times. MR-spectroscopy should be used in the diagnosis and follow-up of headache in patients with systemic lupus erythematosus

Exploring Design Dimensions in Flash-based Mass-memory Devices

Mission-critical space system applications present several issues: a typical one is the design of a mass-memory device (i.e., a solid- state recorder). This goal could be accomplished by using flash- memories: the exploration of a huge number of parameters and trade-offs is needed. On the one hand flash-memories are nonvolatile, shock-resistant and power-economic, but on the other hand their cost is higher than normal hard disk, the number of erasure cycles is bounded and other different drawbacks have to be considered. In addition space environment presents various issues especially because of radiations: the design of a flash- memory based solid-state recorder implies the exploration of different and quite often contrasting dimensions. No systematic approach has so far been proposed to consider them all as a whole: as a consequence the design of flash-based mass-memory device for space applications is intended to be supported by a novel design environment currently under development and refinemen

A Superclass of Edge-Path-Tree graphs with few cliques

Edge-Path-Tree graphs are intersection graphs of Edge-Path-Tree matrices that is matrices whose columns are incidence vectors of edge-sets of paths in a given tree. Edge-Path-Tree graphs have polynomially many cliques as proved in [4] and [7]. Therefore, the problem of finding a clique of maximum weight in these graphs is solvable in strongly polynomial time. In this paper we extend this result to a proper superclass of Edge-Path-Tree graphs. Each graph in the class is defined as the intersection graph of a matrix with no submatrix in a set W of seven small forbidden submatrices. By forbidding an eighth small matrix, our result specializes to Edge-Path-Tree graph