This thesis investigates the fundamental performance of Hierarchical Non-Terrestrial Networks for the 6th generation (6G). 6G communication research is currently focus- ing on non-terrestrial networks (NTNs) to promote ubiquitous and ultra-high-capacity global connectivity. Specifically, multi-layered hierarchical networks, i.e., the orches- tration among different aerial/space platforms, including Unmanned Aerial Vehicles (UAVs), High Altitude Platforms (HAPs), and satellites co-operating at different al- titudes, currently represents one the most attractive technological options to solve coverage and latency constraints associated with the NTN paradigm. However, there are still several issues to be resolved for proper network design. In this thesis, we in- vestigate the propagation model in air/space links and then evaluate the performance of different multi-layered non-terrestrial configurations, and then provide guidelines on the optimal working point(s) for which it is possible to achieve a good compro- mise between improved system flexibility and network performance, with respect to a baseline standalone deployment.

Prior studies have found that human exposure to hazardous air pollutants (HAPs) occurs in homes; however, the depth of these assessments was limited by the extent of the analyzed data. The present Ph.D. dissertation focused on air contaminants of concern in residential buildings, the possible sources of these pollutants, and population subgroups with greater contaminant risk. This research also evaluated the effects of building characteristics and household activity patterns on indoor pollution and risk levels. To this end, an in-depth analysis was performed of data from the Relationships of Indoor, Outdoor and Personal Air (RIOPA) study, one of the most comprehensive exposure assessments to date. Using personal concentrations from the RIOPA study, a cancer risk assessment was performed to identify both important pollutants and populations at higher risk. The analyzed compounds were acetaldehyde, benzene, chloroform, carbon tetrachloride, p-dichlorobenzene (p-DCB), ethylbenzene, formaldehyde, methylene chloride, methyl tert-butyl ether (MTBE), styrene, trichloroethylene and tetrachloroethylene. Results indicate that Hispanics and non-Hispanic whites had median cumulative cancer risks (CCR) of 520×10-6 and 440×10-6, respectively, for which the main contributors were formaldehyde, p-DCB, acetaldehyde, chloroform and benzene. Statistically significant differences in CCR between and within Hispanic and whites were primarily due to exposures to p-DCB. Exposure to formaldehyde was further investigated because this compound was the largest contributor to CCR for 69% of Hispanics and 88% of whites, and because most participants had similar cancer risks from these exposures (median = 260×10-6, coefficient of variance = 28%). Results suggest that the U.S. population may be experiencing chronic exposures because of long-term formaldehyde emissions from pressed-wood materials bound with urea-formaldehyde resins. Source removal may be the most effective way to decrease these chronic exposures. Benzene was also examined further because it is a known human carcinogen. Results show that indoor benzene concentrations increased as the proximity of parked vehicles decreased. Residing in a home with an attached garage could lead to exposures to benzene ten times higher than while commuting in a car in heavy traffic, and with mean excess cancers of 17×10-6. Detached garages could reduce health risks from exposure to benzene and other gasoline-related pollutants. / text

Future wireless networks are envisioned to support a wide range of novel use cases, and connect a massive number of people and devices in an energy efficient way. Several key enabling technologies were considered to support this vision including Internet of Things (IoT) networks, aerial and stratospheric platforms, and reconfigurable intelligent surfaces (RIS). In this dissertation, we study different problems related to the integration between these technologies. First, we propose a cost-effective framework for data collection from IoT sensors using multiple unmanned aerial vehicles (UAVs). This is achieved by effcient clustering of the sensors and optimized deployment of cluster heads (CHs). Then, the number of deployed UAVs and their trajectories will be optimized to minimize the data collection flight time. The impacts of the trajectory approach, environment type, and UAVs' altitude as well as the fairness of UAVs trajectories on the data collection process are investigated. Given that IoT nodes might have different priorities and time deadlines, and respecting the limited battery capacity of UAVs, we enhance the data collection framework to account for these practical constraints. First, an algorithm for finding the minimal number of CHs and their best locations is proposed. Then, the minimal number of UAVs and their trajectories are obtained by solving the associated capacitated vehicle routing problem. The results investigate the impacts of the selected trajectory approach, the battery capacity and time deadlines on the consumed energy, number of visited CHs, and number of deployed UAVs. Next, given the energy issue on aerial platforms, we present our vision for integrating RIS in aerial and stratospheric platforms to provide energy-efficient communications. We propose a control architecture for such integration, discuss its benefits and identify potential use cases and associated research challenges. Then, to substantiate our vision, we study the link budget of RIS-assisted communications under the specular and the scattering reflection paradigms. Specifically, we analyze the characteristics of RIS-equipped stratospheric and aerial platforms and compare their communication performance with that of RIS-assisted terrestrial networks, using standardized channel models. In addition, we derive the optimal aerial platforms placements under both reflection paradigms. The obtained results provide important insights for the design of RIS-assisted communications. For instance, given that a HAPS has a large RIS surface, it provides superior link budget performance in most studied scenarios. In contrast, the limited RIS area on UAVs and the large propagation loss in low Earth orbit (LEO) satellite communications make them unfavorable candidates for supporting terrestrial users. Then, motivated by the demonstrated potential of HAPS equipped with RIS (HAPS-RIS), we propose a solution to support the stranded users in terrestrial networks through a dedicated control station (CS) and HAPS-RIS. We refer to this approach as "beyond-cell" communications. We demonstrate that this approach works in tandem with legacy terrestrial networks to support uncovered or unserved users. Optimal transmit power and RIS unit assignment strategies for the users based on different network objectives are introduced. Furthermore, to increase the percentage of admitted users in an efficient manner, a novel resource-efficient optimization problem is formulated that maximizes the number of connected UEs, while minimizing the total power consumed by the CS and RIS. Since the resulting problem is a mixed-integer nonlinear program (MINLP), a low-complexity two-stage algorithm is developed. Finally, given the different applications and various options of HAPS payload, we envision the use of a multi-mode HAPS that can adaptively switch between different modes so as to reduce energy consumption and extend the HAPS loitering time. These modes comprise a HAPS super macro base station (HAPS-SMBS) mode for enhanced computing, caching, and communication services, a HAPS relay station (HAPS-RS) mode for active communication, and a HAPSRIS mode for passive communication. This multi-mode HAPS ensures that operations rely mostly on the passive communication payload while switching to an energy-greedy active mode only when necessary. We illustrate the envisioned multi-mode HAPS, and discuss its benefits and challenges. Then, we validate the multi-mode efficiency through a case study. At the end of the dissertation, several future research directions are proposed including hybrid orthogonal and non-orthogonal multiple access (OMA/NOMA) beyond-cell communications assisted by HAPS-RIS, configuration of RIS units on stratospheric platforms, energy management for HAPS-RIS, and supporting aerial users through terrestrial RIS.

Se llevaron a cabo cuatro experimentos con el objetivo de evaluar el efecto de la utilización de grasas alteradas o contaminadas recicladas de la alimentación humana, sobre el rendimiento productivo y la salud de pollos de carne, Para ello se utilizaron indicadores tales como incidencias y productividad; niveles de oxidación en sangre (tasa de hemólisis y sustancias reactivas al ácido tiobarbitúrico, TBARs); variación de la microbiota intestinal por t-RFLP; actividad microbiana fermentativa (AGVs) y presencia de microorganismos patógenos (coccidias), además de variaciones en la histomorfología intestinal (longitud de vellosidades, profundidad de criptas y conteo de linfocitos intraepiteliales).Los tratamientos dietéticos fueron elaborados por la Universidad Politécnica de Valencia sobre una ración base constituida de maíz y soja, suplementada con un 6 % de la grasa reciclada y se diferenciaban según el nivel de alteración alto (H) y bajo (L). Los cuatro experimentos contenían los siguientes niveles de alteración o contaminación: Experimento T, Ácidos grasos trans (HT=12,40 % y LT=0,65 %); Experimento D, dioxinas y PCBs (HC=28,80 pg y LC=9,64 pg TEQ/g PCDD/Fs+DL-PCBs de aceite); Experimento P, hidrocarburos aromáticos policíclicos (HP=5,291 ng HAPs/g y LP<18 ngHAPs/g de aceite) y Experimento O, productos de oxidación (HO=6,61 % Polímeros y 67,43 p-anisidina y LO=0,35 % Polímeros y 2,74 p-anisidina).La productividad y salud de los animales, no fue afectada por los tratamientos experimentales, excepto en el caso de la prueba experimental (T), en la que los animales alimentados con la dieta que contenía el nivel de alteración bajo (LT), presentaron un mejor índice de transformación alimenticia (P=0,003), que los animales alimentados con la dieta HT.Un mayor grado de saturación (experimento T) de la grasa del tratamiento HT, se tradujo en una mayor fragilidad (tasa de hemólisis) de la membrana de los eritrocitos (P=0,002), en comparación a su homólogo LT. El efecto de la edad, se tradujo en diferencias estadísticamente significativas (P<0,001), entre animales jóvenes (9 días) y animales de mayor edad (37 días de vida).La evaluación de los dendogramas obtenidos en los cuatro experimentos (t-RFLP) demostró que la composición de la flora microbiana no fue influenciada por los tratamientos. La concentración total de AGVs (actividad microbiana) en las muestras de contenido cecal de los cuatro experimentos no fue afectada por los tratamientos. En cuanto a la presencia de microorganismos patógenos (coccidias) se observó un claro efecto de los tratamientos (P=0,001). No obstante, el conteo ooquistes por gramo, no superó los niveles de concentración considerados peligrosos desde el punto de vista epidemiológico y no se acompañaron de manifestaciones clínicas. El nivel de alteración o contaminación estudiado, no tienen un efecto directo sobre la histomorfología gastrointestinal. Por el contrario, la edad tuvo un efecto significativo, traducido en un general aumento (P<0,001) de la longitud de la vellosidades (LV), una disminución (P<0,001) en las profundidad de criptas (PC) y un descenso (P<0,001) en la proporción de linfocitos intraepiteliales (IEL). Con relación al cociente V/C (relación vellosidad/cripta), en todos los experimentos se alcanzaron los mayores cocientes a 21 días de vida (P<0,001), que a los 9 días de vida de las aves. En conclusión, el nivel de alteración o contaminación estudiado, no presenta un claro efecto sobre los indicadores de salud o productividad analizados. Por el contrario, con la edad del ave aumenta la resistencia a la hemólisis de los eritrocitos, la complejidad de la microbiota cecal y en paralelo, incrementa la longitud de las vellosidades acompañado de un descenso proporcional de la profundidad de criptas y del número de linfocitos intraepiteliales. / Four experiments were realised with the aim of evaluating the effect of the recycled fats of the human feeding on the productive yield and the health of the chickens. Indicators were used such as incidences and productivity; levels of oxidation in blood (rate of haemolysis and reactive substances to tiobarbitúrico acid, TBARs); variation of the intestinal microbiota by t-RFLP; microbial activity (AGVs) and presence of pathogenic microorganisms (coccidias), besides variations in the intestinal histomorfología (length of villious, depth of cripts and count of intraepithelial lymphocytes). The dietetic treatments were elaborated by the Polytechnical University of Valencia on a ration bases constituted of maize and soybean, supplemented with a 6% of the recycled fat and was different itself according to the high level of alteration (H) and low (L). The four experiments contained the following levels of alteration or contamination: Experiment T, Fatty acids trans (HT= 12.40% and LT= 0.65%); Experiment D, dioxins and PCBs (HC=28,80 pg and LC=9,64 pg TEQ/g PCDD/Fs+DL-PCBs of oil); Policiclic aromatic hydrocarbons (HP=5,291 ng HAPs/g and LP<18 ngHAPs/g of oil) y Experiment O, oxidation products (HO=6,61 % Polymer y 67,43 p-anisidine and LO=0,35 % Polymer and y 2,74 p-anisidine). The productivity and health of the animal, were not affected by the experimental treatments, except in the case of the T experiment, in which the animal fed with the diet that contained the level of alteration under (LT), presented a better transformation rate (P=0,003), that the animal fed with the HT. the diet with greater degree of saturation (experiment T) of the fat of treatment HT, it was translated in a greater fragility (haemolysis rate) of the erythrocytes membrane (P=0,002), in comparison to its homologous LT. The effect of the age, was translated in statistically significant differences (P<0,001) between young animal (9 days) and animal of greater age (37 days of age). The evaluation of dendrograms obtained in the four experiments (t- RFLP) demonstrated that the composition of the microbial flora was not influenced by the treatments. The total concentration of VFAs (microbial activity) in the samples of caecal content of the four experiments was not affected by the treatments. As far as the presence of pathogenic microorganisms (coccidia) a clear effect of the treatments was observed (P=0,001). However, the count oocysts, did not surpass the dangerous levels of concentration considered from the point of view epidemiologist and they were not accompanied by clinical manifestations. The level of alteration or studied contamination does not have a direct influence on the gastrointestinal morphology. On the contrary, the age had a significant effect, translated in a general increase (P<0,001) of the villious length (LV), diminishes (P<0,001) of the cript depth (PC) and the diminishes of the intraepithelial lymphocytes (IEL).In conclusion, the level of alteration or studied contamination, does not present a clear effect on the indicators of analyzed health or productivity. On the contrary, with the age of the bird it increases the resistance to the haemolysis of erythrocytes, the complexity of the cecal microbiota and in parallel it increases the length of the intestinal villious accompanied by a proportional reduction of the depth of cripts and the number of intraepithelial lymphocytes.

Στη διπλωματική εργασία μελετάμε τη δυνατότητα συν-λειτουργίας των HAPs και των ad-hoc δικτύων. Μέσα από τη θεωρητική μελέτη και τις προσομοιώσεις προσπαθούμε να μελετήσουμε τις επιδόσεις ενός τέτοιου υβριδικού συστήματος, όσον αφορά τη δρομολόγηση και την αξιοπιστία στη μετάδοση της πληροφορίας. Αρχικά, προχωράμε σε μια θεωρητική μελέτη των στρατοσφαιρικών πλατφόρμων (HAPs) και των ad-hoc δικτύων. Αναφέρουμε δυνατότητες, τεχνολογίες και εφαρμογές των δύο αυτών τηλεπικοινωνιακών τύπων τεχνολογίας. Στη συνέχεια, παρουσιάζουμε το τηλεπικοινωνιακό σενάριο πάνω στο οποίο στηρίχθηκε η προσομοίωση και, τέλος, παρουσιάζουμε αναλυτικά τα αποτελέσματα που προέκυψαν από την πειραματική διαδικασία με μορφή πινάκων και διαγραμμάτων καθώς και τα συμπεράσματα στα οποία καταλήγουμε βάσει των μετρήσεών μας. / --

Satellite communication (SatCom) is an essential component of next-generation wireless communications. The existing terrestrial network will be overwhelmed due to the rapid growth of demand for data and serving remote areas by using only terrestrial networks is demanding. In addition, terrestrial communications are susceptible to natural disasters such as earthquakes and floods. In order to overcome these disadvantages of the terrestrial communication systems, SatCom systems are being deployed and covering remote or sparsely populated areas. However, research on SatCom is still not enough and it has not been studied as much as on terrestrial communication. In this thesis, we investigate and analyze system models using SatCom. Furthermore, we present to improve the performance of SatCom by applying the proposed techniques in terrestrial communications. First of all, we analyze the outage probability and symbol error rate of the SatCom system. In single-beam and multi-beam situations, all factors that can be considered in the SatCom channel model are considered. Since the beam coverage of the satellite is broad, a number of users are randomly distributed within the beam. We investigate the performance of the SatCom system according to the user selection methods considering the user's location as well. Secondly, a system in which multiple gateways transmit signals over multiple beams is taken into account. Many users are placed in each beam, and inter-beam interference exists due to full-frequency reuse. To simultaneously cover the multiple users in the beam, signals are transmitted using non-orthogonal multiple access. In order to maximize system throughput, precoding for interference mitigation and NOMA optimization techniques are proposed. Finally, a cognitive radio network in which high-altitude platforms (HAPs) are applied to conventional SatCom systems and share frequency bands with SatCom is taken into consideration. HAPs are used to cover user-dense areas within satellite beam coverage. In order to properly handle interference caused by spectrum sharing and improve the system data rate, precoding and frequency band allocation schemes are proposed.

Κύριος στόχος της διπλωματικής αυτής εργασίας είναι η διερεύνηση τεχνικών βελτίωσης της προσφερόμενης ποιότητας υπηρεσιών (QoS) σε ένα περιβάλλον συνλειτουργίας πολλαπλών HAPs. Στο περιβάλλον αυτό έχουμε διαφορετικούς τύπους χρηστών που μοιράζονται την περιοχή κάλυψης και το εύρος ζώνης. Παρουσιάζεται το θεωρητικό υπόβαθρο της μελέτης αυτής που περιλαμβάνει τη θεωρία τηλεπικοινωνιακής κίνησης. Αναπτύσσουμε ένα αναλυτικό μοντέλο ώστε να περιγράψουμε το περιβάλλον συνλειτουργίας στο οποίο έχουμε δύο κατηγορίες χρηστών. Η μία κατηγορία αποτελείται από χρήστες που έχουν πλήρη πρόσβαση στα HAPs, ενώ η άλλη κατηγορία αποτελείται από χρήστες με περιορισμένη πρόσβαση στα HAPs. Για να επιτύχουμε αυτή τη βελτίωση του QoS εφαρμόζουμε διάφορους μηχανισμούς περιορισμού. Σκοπός μας είναι να περιοριστεί η πρόσβαση στους πόρους του καναλιού για τους χρήστες με πλήρη πρόσβαση στα HAPs, ώστε να υπάρχει μεγαλύτερη πιθανότητα πρόσβασης για τους χρήστες με περιορισμένη πρόσβαση στα HAPs. Παρουσιάζονται και αναλύονται διάφοροι περιορισμοί με στόχο την εύρεση του καταλληλότερου για την επίτευξη μιας ισορροπημένης και χαμηλής πιθανότητας απόρριψης κλήσης. Αναλύεται, επίσης, και επεξηγείται η παρουσία φαινομένων παρεμβολής και πολυόδευσης στο σύστημά μας καθώς και η εξοικονόμηση συχνοτήτων. / The main objective of this thesis is to investigate techniques for improvement the Quality of Service (QoS) in an environment of multiple HAPs. In this environment there are different user types which share coverage area and radio spectrum. It is presented the theoretical background of this study that includes theory telecommunication traffic. We develop an analytical model to describe system behavior of a coexistence scenario containing two user groups, which have full and limited HAP availability. In order to achieve this improvement of QoS, operate different restrictions. Our aim is to limit access to channel resources to users with full access to HAPs, so that there is a greater probability of access for users with limited access to HAPs. Different types of restriction function are analyzed trying to find the most suitable for achieving a balanced low probability performance to both user groups simultaneously. It is also explained the presence of interference, small-scale fading and saving frequencies.

O aumento na poluição ambiental é na atualidade uma das grandes preocupações em nível mundial. Especificamente, a poluição atmosférica por material particulado tem demostrado ser um fator determinante no desenvolvimento de doenças cardiopulmonares e câncer de pulmão nas populações expostas. O material particulado é constituído por uma mistura complexa de compostos orgânicos e inorgânicos, muitos dos quais possuem potencial mutagênico e genotóxico. As características destes compostos variam em função da suas propriedades físicas, químicas e em razão das condições meteorológicas prevalecentes. A maior parte dos estudos tem se focado em avaliar o potencial genotóxico da fração orgânica do material particulado e poucos estudos têm explorado a fração solúvel em água e a contribuição diferencial das diversas espécies químicas presentes nesta fração para o dano genotóxico. O objetivo deste trabalho foi avaliar os efeitos mutagênicos e genotóxicos in vitro da fração orgânica e da fração solúvel em água de material particulado (MP10) coletado em três locais diferentes do estado de São Paulo e estabelecer a relação entre a composição química e o efeito biológico observado. Para isto, realizou­-se a extração orgânica e solúvel em água de 12 amostras de MP10. A mutagenicidade e genotoxicidade foram avaliadas usando o ensaio de Salmonella/microssoma e o teste de micronúcleos (MN) em células A549 e 16 hidrocarbonetos Policíclicos Aromáticos (HPAs) e 15 metais hidrossolúveis presentes nas amostras foram determinados quimicamente. Adicionalmente, foi determinada a metodologia de extração da fracção solúvel em água e se avaliou a estabilidade química e biológica desta fração. Os resultados indicam que a extração assistida por micro-ondas é um método eficiente para a extração da fração solúvel em agua do MP e que um tempo superior a 60 dias de armazenamento e congelamento deste tipo de extrato tem um efeito significativo sobre os resultados analíticos e a resposta biológica. Foi demonstrado ainda que as duas frações de MP estudadas são responsáveis pela indução do dano ao DNA e que não existe uma relação direta entre a concentração de MP e o efeito genotóxico observado, confirmando a importância do uso de bioensaios na avaliação da genotoxicidade de misturas complexas como o MP. Os HPAs prevalecentes nas amostras de PM10 foram fluorantene e benzo(ghi)perileno. Nos extratos solúveis em água, as maiores concentrações de metais foram determinadas para zinco, ferro e cobre. Confirmou-se que a indução de MN e o ensaio de Salmonella/microssoma representam uma poderosa ferramenta na avaliação da polução atmosférica e que as análises químicas por si só não são suficientes para a proteção e predição dos efeitos biológicos em populações expostas. / The increase of environmental pollution is today one a major concern worldwide. Specifically, air pollution by particulate matter has been shown to be a determining factor in the development of cardiopulmonary disease and lung cancer in exposed populations. The particulate material consists of a complex mixture of organic and inorganic compounds, many of which have mutagenic and genotoxic activity. The characteristics of these compounds vary according to their physical and chemical properties and also to the prevailing weather conditions. Most studies have focused on evaluating the genotoxic potential of the organic fraction of particulate material, but few studies have explored the water­-soluble fraction, and the differential contributions of different chemical species present in this fraction to genotoxic damage. The aim of this study was to evaluate the in vitro mutagenic and genotoxic effects of organic and water-soluble fractions of 12 samples of particulate matter (PM10) collected at three different sites in the state of São Paulo and establish the relationship between the chemical composition and the biological effect observed. The mutagenicity and genotoxicity were evaluated using the Salmonella/microssome test and the micronucleus assay (MN) in A549 cells and 16 Polycyclic Aromatic Hydrocarbons (PAHs) and 15 water-soluble metals present in the samples were chemically determined. Additionally, the extraction method of water- soluble fraction was determined and the chemical and biological stability of this fraction evaluated. The results indicate that the microwave­-assisted extraction is an efficient method for the extraction of the water-soluble compounds of PM and that the freezing and storage of the extract over 60 days has a significant effect on the mutagenic and analytical results of PM samples. It was demonstrated that the two PM fractions studied are responsible for the induction of DNA damage and that there is no direct relationship between the MP concentration and the genotoxic effect observed, confirming the importance of using bioassays in the genotoxicity evaluation of complex mixtures as PM. The PAHs prevailing in our samples were fluoranthene and benzo(ghi)perylene. In the water-soluble extracts, highest concentrations of the elements studied were found for zinc, iron, and copper in the three places of sampling. We confirmed that MN induction and Salmonella/microsome assay represents a powerful tool to evaluate the atmospheric air pollution and that the total concentration of PM and the chemical analyses alone would not be sufficient for the prognosis of biological effects in exposed populations

La pollution des écosystèmes marins côtiers par les hydrocarbures, en particulier les HAPs, est un problème environnemental majeur. Le même constat est fait pour le littoral Sud de Sfax (Tunisie) dont la pollution presque généralisée menace sérieusement les ressources naturelles existantes dans la région. La caractérisation physico-chimique des échantillons marins prélevés à partir des trois ports (plaisance, commerce et pêche) de la ville de Sfax, prouve une contamination par des micropolluants organiques (hydrocarbures) et inorganiques (métaux) qui sont considérés comme des excellents traceurs de la pollution urbaine et industrielle et ils font partie des composés les plus toxiques étant donné leur faible biodégradation. La méthode d’empreinte moléculaire (PCR-SSCP) montre une dominance du domaine Bacteria suivie des Eucarya et des Archaea au sein des échantillons marins étudiés. Les analyses statistiques par le logiciel R ont montré l’absence de corrélation entre la communauté bactérienne identifiée par PCR-SSCP et les paramètres physico-chimiques étudiés.Dans une autre partie de travail, quatre souches bactériennes marines hydrocarbonoclastes ont été isolées et caractérisées sur les plans phénotypique et phylogénétique, après des enrichissements sur des HAPs et sur le pétrole brut: FLU5 de Bacillus stratosphericus, NAPH6 de Pseudomonas aeruginosa, PYR2 de Bacillus licheniformis isolées sur le fluoranthène, le naphtalène et le pyrène, respectivement, en présence de 30 g/l NaCl; et CO100 de Staphylococcus sp., isolée sur le pétrole brut, en présence de 100 g/l NaCl. Les analyses chromatographiques, GC-MS ou GC-FID, montrent les capacités biodégradatives intéressantes de ces composés récalcitrants par les bactéries isolées. En outre, ces quatre souches bactériennes, sont capables de produire des biosurfactants nommés BS-FLU5, BS-NAPH6, BS-PYR2 et BS-CO100, sur plusieurs sources de carbones, y compris l’huile de friture résiduelle, un substrat bon marché, minimisant ainsi le coût élevé de production de ces tensioactifs. Les analyses MALDI-TOF/MS, des biosurfactants BS-FLU5, BS-PYR2 et BS-CO100 purifiés, montrent qu’il s’agit des lipopeptides, les biosurfactants BS-NAPH6 sont de nature rhamnolipidique, sur la base des analyses FTIR. Ces quatre biosurfactants sont caractérisés par des propriétés tensiactives intéressantes : une faible CMC, une importante réduction de la tension de surface... Ils sont stables vis-à-vis d’une large gamme de pH, de température et de salinité. De plus, ces agents tensioactifs sont doués d’activité de remobilisation des hydrocarbures contenus dans des sols pollués par. Les biosurfactants BS-FLU5, BS-PYR2 et BS-CO100, présentent des activités anti-adhésives et anti-biofilms intéressantes contre des biofilms de certains microorganismes pathogènes. Par ailleurs, une propriété cicatrisante remarquable sur des plaies d’excision chez un modèle expérimental de rats de race Wistar, a été montrée par les quatre biosurfactants pour des concentrations de l’ordre de 5 et 10 mg/ml, en comparaison avec un cicatrisant de référence (CICAFLORA®). A noter que, l’évaluation de la cytotoxicité des biosurfactants étudiés, a montré qu’ils n’ont pas des effets toxiques sur des cellules rénales humaines HEK-239 à des concentrations jusqu’à 1000 µg/ml pour BS-FLU5 et BS-CO100 et jusqu’à 200 µg/ml pour BS-NAPH6 et BS-PYR2. La production des biosurfactants de la souche FLU5 à l’échelle pilote (deux fermenteurs de 20 et 100 litres, volume total), en présence d’un milieu économique, montre une augmentation des quantités des biosurfactants produits par rapport à l’échelle laboratoire (erlenmeyer, 1 litre). L’ensemble de ces résultats prometteurs, montrent que les souches marines isolées FLU5, NAPH6, PYR2 et CO100, ainsi que leurs biosurfactants demeurent d’intérêts biotechnologiques pour divers types d’applications, tels que la bioremédiation, l’agroalimentaire, la cosmétique... / Pollution of coastal marine ecosystems by hydrocarbons, in particular polycyclic aromatic hydrocarbons (PAHs), is a major environmental problem. The South coast of Sfax (Tunisia) is an example of a polluted ecosystem subject to both urbanization and industrialization including the outfall of untreated domestic sewage and wastewaters, fishery activities, as well as ship traffic and boat pollution. The physico-chemical characterization of the seawater taken from three harbours (pleasure, commercial and fishing) of the city of Sfax, showed a heavy contamination by organic and inorganic micropollutants. These are excellent tracers of urban and industrial pollution, and they are among the most toxic compounds due to their low biodegradation.The molecular fingerprinting technique (PCR-SSCP) showed the dominance of the Bacteria domain followed by Eucarya and Archaea within the studied marine samples. Statistical analysis using the R software, showed that no correlation was identified between the bacterial community identified by PCR-SSCP and the studied physico-chemical parameters.In another part, four marine, aerobic and hydrocarbonoclastic strains: Bacillus stratosphericus FLU5, Pseudomonas aeruginosa NAPH6, Bacillus licheniformis PYR2, isolated after enrichments on fluoranthene, naphthalene and pyrene, respectively, and in the presence of 30 g/l NaCl. Strain Staphylococcus sp. CO100 was isolated after enrichment on crude oil, in the presence of 100 g/l. Chromatographic analysis (GC-MS or GC-FID), showed the interesting biodegradative capacities of these recalcitrant compounds by the isolated bacteria.Besides, these strains showed their capacity to produce efficient surface active agents BS-FLU5, BS-NAPH6, BS-PYR2 and BS-CO100, on several substrates and in particular the residual frying oil, which is a cheap and renewable carbon source alternative, thus minimizing the high cost of producing surfactants. The MALDI-TOF/MS analysis of the purified BS-FLU5, BS-PYR2 and BS-CO100 biosurfactants revealed that they are belonging to lipopeptide family. FTIR analysis showed the glycolipid nature, more precisely the rhamnolipid type, of biosurfactant BS-NAPH6.These four biosurfactants are characterized by interesting tensioactive properties (low CMC, important surface tension reduction...). Furthermore, these surface active agents showed interest stability against a broad range of pH, temperature and salinity. The application of these biosurfactants, in oil recovery, from hydrocarbons-contaminated soil, showed that they were more effective on the hydrocarbon-remobilization than some tested synthetic surfactants. The biosurfactants BS-FLU5, BS-PYR2 and BS-CO100, were found to have notable anti-adhesif and anti-biofilm activities, being able to prevent and eliminate the biofilm formation by pathogenic microorganisms. Moreover, the four tested biosurfactants showed an interesting healing activity, on the wound site in a rat model. They increased significantly the percentage of wound closure when compared to the untreated and CICAFLORA® (a reference pharmaceutical product) treated groups, using two different concentrations (5 and 10 mg/l). Interestingly, the evaluation of the cytotoxicity of the studied biosurfactants, showed that they have no toxic effects on human HEK-239 cells at concentrations up to 1000 μg/ml for BS-FLU5 and BS-CO100 and up to 200 μg/ml for BS-NAPH6 and BS-PYR2. An attempt to produce biosurfactant produce by strain FLU5 on a pilot-scale (fermentors of 20 and 100 liter, as total volume), using a cost-effective medium, was also performed. Preliminary results showed an increase in the quantities of biosurfactantsBS-FLU5 produced on a pilot-scale compared to the lab-scale (Erlenmeyer of 1 liter).These results highlight the interest for potential use of strains FLU5, NAPH6, PYR2 and CO100, as well as their biosurfactants, in a wide variety of industrial, environmental and biotechnological applications.

O aumento na poluição ambiental é na atualidade uma das grandes preocupações em nível mundial. Especificamente, a poluição atmosférica por material particulado tem demostrado ser um fator determinante no desenvolvimento de doenças cardiopulmonares e câncer de pulmão nas populações expostas. O material particulado é constituído por uma mistura complexa de compostos orgânicos e inorgânicos, muitos dos quais possuem potencial mutagênico e genotóxico. As características destes compostos variam em função da suas propriedades físicas, químicas e em razão das condições meteorológicas prevalecentes. A maior parte dos estudos tem se focado em avaliar o potencial genotóxico da fração orgânica do material particulado e poucos estudos têm explorado a fração solúvel em água e a contribuição diferencial das diversas espécies químicas presentes nesta fração para o dano genotóxico. O objetivo deste trabalho foi avaliar os efeitos mutagênicos e genotóxicos in vitro da fração orgânica e da fração solúvel em água de material particulado (MP10) coletado em três locais diferentes do estado de São Paulo e estabelecer a relação entre a composição química e o efeito biológico observado. Para isto, realizou­-se a extração orgânica e solúvel em água de 12 amostras de MP10. A mutagenicidade e genotoxicidade foram avaliadas usando o ensaio de Salmonella/microssoma e o teste de micronúcleos (MN) em células A549 e 16 hidrocarbonetos Policíclicos Aromáticos (HPAs) e 15 metais hidrossolúveis presentes nas amostras foram determinados quimicamente. Adicionalmente, foi determinada a metodologia de extração da fracção solúvel em água e se avaliou a estabilidade química e biológica desta fração. Os resultados indicam que a extração assistida por micro-ondas é um método eficiente para a extração da fração solúvel em agua do MP e que um tempo superior a 60 dias de armazenamento e congelamento deste tipo de extrato tem um efeito significativo sobre os resultados analíticos e a resposta biológica. Foi demonstrado ainda que as duas frações de MP estudadas são responsáveis pela indução do dano ao DNA e que não existe uma relação direta entre a concentração de MP e o efeito genotóxico observado, confirmando a importância do uso de bioensaios na avaliação da genotoxicidade de misturas complexas como o MP. Os HPAs prevalecentes nas amostras de PM10 foram fluorantene e benzo(ghi)perileno. Nos extratos solúveis em água, as maiores concentrações de metais foram determinadas para zinco, ferro e cobre. Confirmou-se que a indução de MN e o ensaio de Salmonella/microssoma representam uma poderosa ferramenta na avaliação da polução atmosférica e que as análises químicas por si só não são suficientes para a proteção e predição dos efeitos biológicos em populações expostas. / The increase of environmental pollution is today one a major concern worldwide. Specifically, air pollution by particulate matter has been shown to be a determining factor in the development of cardiopulmonary disease and lung cancer in exposed populations. The particulate material consists of a complex mixture of organic and inorganic compounds, many of which have mutagenic and genotoxic activity. The characteristics of these compounds vary according to their physical and chemical properties and also to the prevailing weather conditions. Most studies have focused on evaluating the genotoxic potential of the organic fraction of particulate material, but few studies have explored the water­-soluble fraction, and the differential contributions of different chemical species present in this fraction to genotoxic damage. The aim of this study was to evaluate the in vitro mutagenic and genotoxic effects of organic and water-soluble fractions of 12 samples of particulate matter (PM10) collected at three different sites in the state of São Paulo and establish the relationship between the chemical composition and the biological effect observed. The mutagenicity and genotoxicity were evaluated using the Salmonella/microssome test and the micronucleus assay (MN) in A549 cells and 16 Polycyclic Aromatic Hydrocarbons (PAHs) and 15 water-soluble metals present in the samples were chemically determined. Additionally, the extraction method of water- soluble fraction was determined and the chemical and biological stability of this fraction evaluated. The results indicate that the microwave­-assisted extraction is an efficient method for the extraction of the water-soluble compounds of PM and that the freezing and storage of the extract over 60 days has a significant effect on the mutagenic and analytical results of PM samples. It was demonstrated that the two PM fractions studied are responsible for the induction of DNA damage and that there is no direct relationship between the MP concentration and the genotoxic effect observed, confirming the importance of using bioassays in the genotoxicity evaluation of complex mixtures as PM. The PAHs prevailing in our samples were fluoranthene and benzo(ghi)perylene. In the water-soluble extracts, highest concentrations of the elements studied were found for zinc, iron, and copper in the three places of sampling. We confirmed that MN induction and Salmonella/microsome assay represents a powerful tool to evaluate the atmospheric air pollution and that the total concentration of PM and the chemical analyses alone would not be sufficient for the prognosis of biological effects in exposed populations