5,10,15,20-Tetra­kis(1-methyl­pyridinium-4-yl)porphyrin tetra­iodide tetra­hydrate

The asymmetric unit of the title compound, C44H38N8 2+·4I−·4H2O, comprises two halves of non-equivalent cations of 5,10,15,20-tetra­kis­(1-methyl­pyridinium)porphyrin (with the full mol­ecule of each completed by the application of inversion symmetry), four charge balancing iodide anions and four water mol­ecules of crystallization (two water mol­ecules are fully occupied and four mol­ecules have a site occupancy of 50%). The porphyrin cations are arranged into supramolecular columns parallel to the b axis, mediated by π–π [centroid–centroid distance = 3.762 (4) Å] and C—H⋯π supra­molecular inter­actions [C⋯centroid distance = 3.522 (7) Å, C—H⋯centroid = 128°], leading to the formation of columns parallel to the b axis. The close packing leads to the presence of a one-dimensional channel filled with partially occupied water mol­ecules engaged in O—H⋯O and O—H⋯I hydrogen bond

Antimicrobial Photodynamic Therapy: Study of Bacterial Recovery Viability and Potential Development of Resistance after Treatment

Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process

Phage Therapy and Photodynamic Therapy: Low Environmental Impact Approaches to Inactivate Microorganisms in Fish Farming Plants

Owing to the increasing importance of aquaculture to compensate for the progressive worldwide reduction of natural fish and to the fact that several fish farming plants often suffer from heavy financial losses due to the development of infections caused by microbial pathogens, including multidrug resistant bacteria, more environmentally-friendly strategies to control fish infections are urgently needed to make the aquaculture industry more sustainable. The aim of this review is to briefly present the typical fish farming diseases and their threats and discuss the present state of chemotherapy to inactivate microorganisms in fish farming plants as well as to examine the new environmentally friendly approaches to control fish infection namely phage therapy and photodynamic antimicrobial therapy

Réduction du nombre de variables en analyse de relations linéaires

This thesis takes place in automatic verification of numerical properties, mainly for embeded softwares. During verification one must represents in a finished way possibly infinite sets of values, for that a solution is use of convex polyhedra. This representation is precise but expensive so maximal number of variables is limited. The goal of this thesis is to increase the maximum number of variables which it is possible to represent. Two approaches were considered then tested. First we wanted to benefit from the presence of linear equations to eliminate a variable by equation. This approach appeared, in experiments, rather disappointing. Another apprroach, more promising, isthe use of cartesian product. The idea is then to represent independently the variables whose evolution is not dependent. This decomposition can be improved through a change of basis. An analyser wasdone in order to test these two approaches.Cette thèse s'inscrit dans la vérification automatique de propriétés numériques de programmes, principalement des logiciels embarqués. Lors de la vérification on doit représenter de façon finie des ensembles éventuellement infinis de valeurs, pour cela une solution possible est l'utilisation de polyèdres convexes. Cette représentation est précise mais coûteuse ce qui limite le nombre de variables qu'il est possible de manipuler. Le but de cette thèse est d'augmenter le nombre maximal de variables qu'il est possible de représenter. Deux approches ont été envisagées puis testées. Dans un premier temps on a voulu tirer profit de la présence d'équations affines pour éliminer une variable par équation. Cette approche s'est révélée, expérimentalement, assez décevante. Une autre approche, bien plus prometteuse, est l'utilisation du produit cartésien. L'idée est alors de représenter indépendamment les variables dont l'évolution n'est pas liée. Cette décomposition peut être améliorée grâce à un changement de base. Un analyseur a été réalisé afin de tester ces deux approches