Anthocyanins, pigment stability and antioxidant activity in jabuticaba [Myrciaria cauliflora (Mart.) O. Berg]

Different solvents were evaluated for the extraction of jabuticaba anthocyanin pigments, identifying, quantifying and verifying the stability of the anthocyanins, as well as the conduction of three antioxidant activity assays and determination of the vitamin C levels. The maceration with ethanol acidified with HCl 1.5 mol L-1 (85:15) provides better pigment extraction and stability. The skin is anthocyanin rich, presenting 1.59 and 2.06 g 100 g-1 of dry matter in the Paulista and Sabará varieties, respectively. Cyanidin 3-glucoside is the majority pigment of the skins, followed by delphinidin 3-glucoside. The highest level of vitamin C was found in the skins and seeds of both varieties. It was verified that the skins, presented more antioxidant activity, in free radical capture, as well as in retarding the lipid oxidation process.

Highly textured Sr, Nb, co-doped BiFeO3 thin films grown on SrRuO3/Si substrates by rf-sputtering

In this study, (011)-highly oriented Sr, Nb co-doped BiFeO3 (BFO) thin films were successfully grown on SrRuO3/Si substrates by rf-magnetron sputtering. The presence of parasite magnetic phases was ruled out based on the high resolution x-ray diffraction data. BFO films exhibited a columnar-like grain growth with rms surface roughness values of 5.3 nm and average grain sizes of 65-70 nm for samples with different thicknesses. Remanent polarization values (2Pr) of 54 lC cm 2 at room temperature were found for the BFO films with a ferroelectric behavior characteristic of an asymmetric device structure. Analysis of the leakage mechanisms for this structure in negative bias suggests Schottky injection and a dominant Poole-Frenkel trap-limited conduction at room temperature. Oxygen vacancies and Fe3þ/Fe2þ trap centers are consistent with the surface chemical bonding states analysis from x-ray photoelectron spectroscopy data. The (011)-BFO/ SrRuO3/Si film structure exhibits a strong magnetic interaction at the interface between the multiferroic film and the substrate layer where an enhanced ferromagnetic response at 5 K was observed. Zero-field cooled (ZFC) and field cooled (FC) magnetization curves of this film system revealed a possible spin glass behavior at spin freezing temperatures below 30 K depending on the BFO film thickness.

A Database of >20 keV Electron Green's Functions of Interplanetary Transport at 1 AU

We use interplanetary transport simulations to compute a database of electron Green's functions, i.e., differential intensities resulting at the spacecraft position from an impulsive injection of energetic (>20 keV) electrons close to the Sun, for a large number of values of two standard interplanetary transport parameters: the scattering mean free path and the solar wind speed. The nominal energy channels of the ACE, STEREO, and Wind spacecraft have been used in the interplanetary transport simulations to conceive a unique tool for the study of near-relativistic electron events observed at 1 AU. In this paper, we quantify the characteristic times of the Green's functions (onset and peak time, rise and decay phase duration) as a function of the interplanetary transport conditions. We use the database to calculate the FWHM of the pitch-angle distributions at different times of the event and under different scattering conditions. This allows us to provide a first quantitative result that can be compared with observations, and to assess the validity of the frequently used term beam-like pitch-angle distribution.

Resistance Switching in Transparent Magnetic MgO Films

We have studied the abrupt and hysteretic changes of resistance in MgO-based capacitor devices. The switching behavior is discussed in terms of the formation and rupture of conduction filaments due to the migration of structural defects in the electric field, together with the redox events which affects the mobile carriers. The results presented in this paper suggest that MgO transparent films combining ferromagnetism and multilevel switching characteristics might pave the way for a new method for spintronic multibit data storage.

Kerrostumien muodostumisen määritys sondin lämmönsiirron perusteella

Diplomityön tavoitteena oli tutkia kerrostumien muodostumista voimalaitoskattiloiden lämpöpinnoille ja niiden vaikutusta lämmönsiirtoon. Kerrostumien vaikutusta lämpöpintojen lämpötiloihin tutkittiin kerrostumasondin avulla kierto- ja kerrosleijukattiloissa. Saadun mittausaineiston muodostettiin mittaustilannetta vastaava laskentamalli, jonka avulla pystytään selvittämään voimalaitoksen lämpöpintojen likaantumista käyttöperiodin aikana. Työn alussa tarkasteltiin kerrostumien muodostumismekanismeja lämmönsiirtopinnoille, kerrostumien ominaisuuksia ja virtausympäristön vaikutusta lämmönsiirtoon. Poltossa syntyvä tuhka kiinnittyy eri mekanismeilla kattilan seinille ja lämpöpinnoille riippuen polttoaineesta ja ympäröivistä olosuhteista. Likakerrosten muodostuminen lämmönsiirtimen pinnalle pienentää putkeen siirtyvää lämpövirtaa ja alentaa kattilan hyötysuhdetta. Kerrostumien lämmönjohtumisesta ja mikrorakenteesta on hyvin vähän kokeellisen tietoa, mikä vaikeuttaa reaalisten mallien muodostamista kattilan käyttäytymisestä sen likaantuessa.Työn kokeellisessa osassa tarkasteltiin kahdella eri kattilalla tehtyjä mittauksia. Mittaukset tehtiin kerrostumasondilla, jonka lämmönsiirrosta luotiin laskentamalli SIMULINK-simulointiohjelmalla. Mittaustuloksina saatiin kolmen eri pinnan lämpötilat, jotka muuttuivat kerrostuman ja jäähdytyksen vaikutuksesta. Laskentamallista muokattiin mittaustilanteita vastaava, jolloin lämpötilamuutoksista nähdään likakerroksen ominaisuuksien vaikutus lämmönsiirtoon. Sondista muodostettiin myös FLUENT-malli, jolla tarkasteltiin yksittäisen putken virtauskenttää sekä kahden lähekkäin olevan putken vaikutusta virtaukseen.

Gamma-ray emission from microquasars: a numerical model for LSI+61º303

We explore the possible association between the microquasar LSI +61°303 and the EGRET source 2CG 135+01/3EG J0241+6103 by studying, with a detailed numerical model, whether this system can produce the emission and the variability detected by EGRET (>100 MeV) through inverse Compton (IC) scattering. Our numerical approach considers a population of relativistic electrons entrained in a cylindrical inhomogeneous jet, interacting with both the radiation and the magnetic fields, taking into account the Thomson and Klein-Nishina regimes of interaction. Our results reproduce the observed spectral characteristics and variability at γ-rays, thus strengthening the identification of LSI +61°303 as a high-energy γ-ray source.

Kupariliekkisulatusuunin lampohavioiden maarittaminen

Työn teoriaosassa käydään läpi kuparisulaton prosessi pääpiirteittäin, jonka jälkeen siirrytään lämmönsiirron teoriaan. Lämpö siirtyy kolmella penis mekanismilla: johtumalla, säteilemällä ja konvektiolla. Naiden ilmiöiden vaikutusta kupariliekkisulatusuunin eri osissa tapahtuviin lämpöhäviöihin on käyty läpi. Lisaksi työstä löytyy kupariliekkisulatusuunin lämpö- ja ainetase sekä erilaisten lämpötilanmittauslaitteiden vertailua sekä mitä tulee ottaa huomioon lämpötiloja mitatessa. Työn kokeellisessa osassa esitellään lämpötilanmittausten perusteella lasketut kupariliekkisulatusuunin eri osien lämpöhäviöiden suuruudet mittauskampanjan ajalta. Saatuja tuloksia on vertailtu kirjallisuudesta löydettyihin aikaisempiin arvoihin. Uunin keskimääräiseksi kokonaislämpöhäviöksi saatiin 9,8 MW mittauskampanjan ajalle. Lisäksi on vertailtu uunin erilaisten ajoarvojen, kuten rikaste-, lentopöly-, murska-, ja kuonarikastesyötön suuruuden sekä öljyn syötön ja rikasteseoksen vaihtumisen vaikutusta lämpöhäviöihin sekä mietitty muita mahdollisia syitä lämpöhäviöiden vaihtelulle.

Structural factors impacting carrier transport and electroluminescence from Si nanocluster-sensitized Er ions.

We present an analysis of factors influencing carrier transport and electroluminescence (EL) at 1.5 µm from erbium-doped silicon-rich silica (SiOx) layers. The effects of both the active layer thickness and the Si excess content on the electrical excitation of erbium are studied. We demonstrate that when the thickness is decreased from a few hundred to tens of nanometers the conductivity is greatly enhanced. Carrier transport is well described in all cases by a Poole-Frenkel mechanism, while the thickness-dependent current density suggests an evolution of both density and distribution of trapping states induced by Si nanoinclusions. We ascribe this observation to stress-induced effects prevailing in thin films, which inhibit the agglomeration of Si atoms, resulting in a high density of sub-nm Si inclusions that induce traps much shallower than those generated by Si nanoclusters (Si-ncs) formed in thicker films. There is no direct correlation between high conductivity and optimized EL intensity at 1.5 µm. Our results suggest that the main excitation mechanism governing the EL signal is impact excitation, which gradually becomes more efficient as film thickness increases, thanks to the increased segregation of Si-ncs, which in turn allows more efficient injection of hot electrons into the oxide matrix. Optimization of the EL signal is thus found to be a compromise between conductivity and both number and degree of segregation of Si-ncs, all of which are governed by a combination of excess Si content and sample thickness. This material study has strong implications for many electrically driven devices using Si-ncs or Si-excess mediated EL.

Large Magnetoresistance in Fe/MgO/FeCo(001) Epitaxial Tunnel-Junctions on GaAs(001).

We present tunneling experiments on Fe~001!/MgO~20 Å!/FeCo~001! single-crystal epitaxial junctions of high quality grown by sputtering and laser ablation. Tunnel magnetoresistance measurements give 60% at 30 K, to be compared with 13% obtained recently on ~001!-oriented Fe/amorphous-Al2O3 /FeCo tunnel junctions. This difference demonstrates that the spin polarization of tunneling electrons is not directly related to the density of states of the free metal surface Fe~001! in this case but depends on the actual electronic structure of the entire electrode/barrier system.

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

BS-SEM evaluation of the tisular interactions between cortical bone and calcium-phosphate covered titanium implants

The improvement of the reliability of the contact between the osseous tissues and the implant materials has been tested by recovering the metallic implants with ceramic materials, usually calcium phosphates. In our study, the calcium phosphate recovering layers were deposited by means of a pulsed-laser deposition technique. Our aim was to to evaluate the tissue interactions established between cortical bone and titanium implants covered by five different layers, ranging from amorphous calcium phosphate to crystalline hydroxyapatite, obtained by altering the parameters of the laser ablation process. The surgical protocol of the study consisted in the simultaneous implantation of the five types of implants in both the tibial dyaphisis of three Beagle dogs, sacrificed respectively one, two and three months after the last surgical procedures. After the sacrifice, the samples were submitted to a scheduled procedure of embedding in plastic polymers without prior decalcification, in order to perform the ultrastructural studies: scanning microscopy with secondary and backscattered electrons (BS-SEM). Our observations show that both in terms of the calcified tissues appearing as a response to the presence of the different coatings and of time of recovering, the implants coated with crystalline calcium phosphate layers by laser ablation present a better result than the amorphous-calcium-phosphate-coated implants. Moreover, the constant presence of chondroid tissue, related with the mechanical induction by forces applied on the recovering area, strongly suggests that the mechanisms implied in osteointegration are related to endomembranous, rather than endochondral ossification processes

Hakkuriteholähteen säädön suunnittelu

Diplomityö on tehty osana ETX-tutkimushanketta: 'Volyymiteholähteen suunnittelumetodien kehitys ja optimointi DFM-viitekehyksessä'. Työssä suunnitellaan hakkuriteholähteelle säätäjä. Tähän suunnittelun sektoriin syventyminen on teollisuudessa jäänyt monesti vähälle. Säätö on tavallisesti ajan puutteen ja apuvälineiden käytön osaamattomuuden tai puuttumisen takia suunniteltu kokeilemalla. Työssä muodostetaan jännitemuotoisesti säädetylle hakkurille piensignaalimallilla linearisoidut siirtofunktiot, joiden perusteella voidaan tarkastella hakkurin stabiilisuutta takaisinkytketyssä säätösilmukassa. Stabiiliustarkastelu tehdään taajuustasossa käyttäen Bode-kuvaajia. Näiden kuvaajien perusteella viritetään järjestelmään säätäjä. Säätäjän toimintaa aikatasossa tarkastellaan simuloimalla ja reaalisen laitteen toimimista laboratorioprototyypin avulla. Tulosten perusteella voidaan todeta, että jännitemuotoisella säädöllä flyback-hakkuri saadaan nopeaksi epäjatkuvalla käämivirralla. Mikäli halutaan hakkurin toimivan jatkuvalla käämivirralla, on syytä käyttää muita säätömenetelmiä, esimerkiksi huippuvirtasäätöä.

Compositional influence on the electrical performance of zinc indium tin oxide transparent thin-film transistors

In this work, zinc indium tin oxide layers with different compositions are used as the active layer of thin film transistors. This multicomponent transparent conductive oxide is gaining great interest due to its reduced content of the scarce indium element. Experimental data indicate that the incorporation of zinc promotes the creation of oxygen vacancies. In thin-film transistors this effect leads to a higher threshold voltage values. The field-effect mobility is also strongly degraded, probably due to coulomb scattering by ionized defects. A post deposition annealing in air reduces the density of oxygen vacancies and improves the fieldeffect mobility by orders of magnitude. Finally, the electrical characteristics of the fabricated thin-film transistors have been analyzed to estimate the density of states in the gap of the active layers. These measurements reveal a clear peak located at 0.3 eV from the conduction band edge that could be attributed to oxygen vacancies.

Induced pluripotent stem cells as a promising tool to study the effect of interleukin-22 in multiple sclerosis

La sclérose en plaques (SEP) est une maladie démyélinisante du système nerveux central (SNC) provoquant des pertes motrices, sensitives et cognitives. La SEP se déclare chez le jeune adulte ayant des prédispositions génétiques, mais semble induite, par des facteurs environnementaux. La SEP touche principalement les femmes et sa prévalence dans les zones à haut risque, tel que la Suisse, est de 0.1%. Bien que son étiologie exacte reste méconnue, nous savons que la maladie est médiée par des lymphocytes T autoréactifs périphériques, qui infiltrent le SNC où ils activent d'autres cellules immunitaires ainsi que les cellules du SNC elles-mêmes, créant un foyer inflammatoire, qui va attaquer et finir par tuer les oligodendrocytes et les neurones. Les épisodes inflammatoires sont entrecoupés par des phases de rémission associées à une guérison partielle des lésions. Cette première phase de la maladie, comprenant des épisodes inflammatoires et de rémissions est appelé SEP récurrente-rémittente (SEP-RR) et touche 90% des patients. Elle évolue, dans deux-tiers des cas, vers une SEP secondaire progressive (SEP-SP), qui est caractérisée par une progression constante de la maladie, associée à une réduction de l'inflammation mais une augmentation de la neurodégénérescence. Les patients souffrants de SEP primaire progressive (SEP-PP) développent directement les symptômes de la phase progressive de la maladie. Les thérapies disponibles ont considérablement amélioré l'évolution de la maladie des patients SEP-RR, en agissant sur une diminution de la réponse immunitaire et donc de l'inflammation. Cependant, ces traitements sont inefficaces chez les patients SEP-SP et SEP-PP, n'agissant pas sur la neurodégénérescence. IL-22, une cytokine sécrétée notoirement par les cellules Th17, a été associée à la SEP en contribuant à la perméabilisation de la barrière hémato-encéphalique et à l'inflammation du SNC, qui sont des étapes clés de la pathogenèse de la maladie. En outre, le gène codant pour un inhibiteur puissant d'IL- 22, 'IL-22 binding protein' (IL-22BP), a été démontré comme un facteur de risque de la SEP. Ces indices nous ont poussés à nous intéresser de plus près au rôle de l'IL-22 dans la SEP. Nous avons pu montrer qu'IL-22 et IL-22BP étaient augmentées dans le sang des patients SEP par rapport à des sujets sains. Nous avons trouvé qu'IL-22 cible spécifiquement les astrocytes dans le SNC et que son récepteur est particulièrement exprimé dans les lésions des patient SEP. Contre toute attente, nous avons pu montrer que l'IL-22 semble soutenir la survie des astrocytes. Cette découverte, suggérant qu'IL-22 serait protecteur pour le SNC et pour la SEP, confirme de récentes publications et ouvre la voie à de potentielles applications thérapeutiques. En parallèle, dans le but de mieux comprendre l'immunopathogenèse de la SEP, nous avons développé les techniques de culture de cellules souches pluripotentes induites (iPSC). Nos iPSC sont dérivées du sang des donneurs et acquièrent toutes les propriétés des cellules souches embryonnaires après induction. Les iPSC peuvent ensuite être différenciées en différents types de cellules, dont les cellules du SNC. Nous avons ainsi pu obtenir avec succès des neurones, dérivés de cellules du sang, en passant par le stade des iPSC. La prochaine étape consiste à générer des cultures d'astrocytes et d'oligodendrocytes et ainsi obtenir les principales cellules du SNC, le but étant de former de véritables 'cerveaux-en-culture'. Cet outil semble particulièrement adapté à l'étude de l'activité de diverses molécules sur les cellules du SNC, comme par exemple l'IL-22 et d'autres molécules ayant un potentiel intérêt thérapeutique au niveau du SNC. Le but ultime étant de développer des co-cultures de cellules du SNC avec des cellules immunitaires autologues, de patients SEP et de sujets sains, afin de mettre en évidence l'attaque des cellules du SNC par des leucocytes autoréactifs. Ce projet prospectif a permis d'accroître nos connaissance sur des aspects immunitaires de la SEP et à pour but de mieux comprendre l'immunopathogenèse de la SEP afin d'élaborer de nouvelles stratégies thérapeutiques. -- La sclérose en plaques est une maladie auto-inflammatoire du système nerveux central conduisant à la destruction de la myéline, indispensable à la conduction nerveuse, et finalement à la mort des neurones eux-mêmes. Cela a pour conséquence des pertes motrices, sensorielles et cognitives, qui ont tendance à s'aggraver au fil de la maladie. Elle se déclare chez le jeune adulte, entre l'âge de 20 et 40 ans, et prédomine chez la femme. En Suisse, environ une personne sur l'OOO est atteinte de sclérose en plaques. Les causes exactes de cette maladie, qui incluent des facteurs génétiques et environnementaux, sont encore mal connues. Des traitements de plus en plus efficaces ont été développés ces dernières années et ont permis de drastiquement améliorer l'évolution de la maladie chez les patients atteints de sclérose en plaques. Cependant, ces traitements ne sont efficaces que sur certaines catégories de patients et peuvent engendrer de lourds effets secondaires. Ces thérapies agissent presque exclusivement sur les cellules du système immunitaire en les désactivant partiellement, mais pas sur les cellules nerveuses, qui sont pourtant celles qui conditionnent le devenir du patient. Le développement de médicaments protégeant ou permettant la régénération des cellules du système nerveux central est donc primordial. L'étude de l'interleukine-22 nous a permis de montrer que cette cytokine ('hormone' du système immunitaire) pouvait cibler spécifiquement les astrocytes, des cellules gliales qui jouent un rôle central dans le maintien de l'équilibre du système nerveux central. Nos recherches ont montré que cette interleukine-22 permettrait une meilleure survie des astrocytes durant la phase aiguë de la maladie et aurait aussi des propriétés neuroprotectrices. En parallèle, nous sommes en train de développer un nouveau modèle in vitro d'étude de la sclérose en plaques grâce à la technologie des cellules souches pluripotentes induites. Ces cellules souches sont induites à partir de cellules du sang du donneur et acquièrent toutes les caractéristiques des cellules souches embryonnaires présentes dans un organisme en formation. Ainsi, ces cellules souches pluripotentes ont, par exemple, la capacité de se différencier en cellules du système nerveux central. Nous avons pu, de cette manière, obtenir des neurones. Le but ultime serait de pouvoir reconstituer une ébauche de cerveau in vitro, en cultivant ensemble différents types de cellules du système nerveux central, afin d'y réaliser des expériences avec des cellules immunitaires du même donneur. Ces travaux ont pour but d'améliorer notre compréhension de la pathogenèse de la sclérose en plaques et de permettre le développement de nouvelles stratégies thérapeutiques. --Multiple sclerosis (MS) is a demyelinating disease of the central nervous system leading to cognitive, sensitive and motor disabilities. MS occurs in genetically predisposed young adults with probable environmental triggers. MS affects predominantly women and its prevalence in high risk area such as Switzerland is 0.1%. Though its exact aetiology remains undetermined, we know that autoreactive T cells from de periphery are reactivated and recruited into the central nervous system (CNS) were they further activate other immune cells and resident cells, creating inflammatory foci, where oligodendrocytes and neurons are insulted and, eventually, killed. Inflammatory episodes, called relapses, are interspersed with remission phases where partial recovery of the lesions occurs. This first phase of the disease, occurring in 90% of the patients, is called relapsing-remitting MS (RR-MS) and is leading, in two-third of the cases, to secondary-progressive MS (SP-MS), where there is a continuous steady progression of the disease, associated with reduced inflammation but increased neurodegeneration. Primary-progressive MS (PP-MS) patients experience directly this progressive phase of the disease. Whereas disease modifying therapies have dramatically ameliorated the disease course of RR-MS patients by dampening immunity and, in turn, inflammation, treatments of SP-MS and PP-MS patients, who suffer primarily from the neurodegenerative aspect of the disease, are still inexistent. IL-22, a pro-inflammatory Th17 cell cytokine, has been associated with MS by participating to blood-brain barrier infiltration and CNS inflammation, which are crucial steps in MS pathogenesis. In addition, the gene coding for IL-22 binding protein (IL-22BP), which is a potent secreted IL-22 inhibitor, has been associated with MS risk. These findings call for further investigation on the role of IL-22 in MS. We detected increased IL-22 and IL-22BP in the blood of MS patients as compared to healthy controls. Acting exclusively on cells of nonhematopoietic origin, we found that IL-22 targets specifically astrocytes in the CNS and that its receptor is highly expressed in the lesion of MS patients. Unexpectedly, we found that IL-22 seems to promote survival of astrocytes. This finding, suggesting that IL-22 might be protective for the CNS in the context of MS, is consistent with recent publications and might open putative therapeutic applications at the CNS level. In parallel, with the aim of better understanding the immunopathogenesis of MS, we developed induced pluripotent stem cell (iPSC) techniques. IPSC are derived from blood cells of the donors and bear embryonic stem cell properties. IPSC can be differentiated into various cell types including CNS cells. We successfully obtained neurons derived from the donor blood cells, through iPSC. We further aim at developing astrocytes and oligodendrocytes cultures to recreate a 'brain-in-a-dish'. This would be a powerful tool to test the activity of various compounds on CNS cells, including IL-22 and other putative neuroprotective drugs. Ultimately, the goal is to develop co-cultures of CNS cells with autologous immune cells of MS patients as well as healthy controls to try to expose evidence of CNS cells targeted by autoreactive leukocytes. This prospective project has increased our knowledge of immune aspects of MS and further aims at better understanding the immunopathology of MS in order to pave the way to the elaboration of new therapeutic strategies.