In situ and remote sensing signature of meddies east of the mid-Atlantic ridge

[EN] Mediterranean Water eddies (meddies) are thought to play an important climatic role. Nevertheless, their dynamics are not sufficiently known because of difficulties encountered in their observation. Though propagating below the main thermocline, a number of pieces of evidence of sea surface manifestation of meddies are collected. The present work is based on joint in situ and altimetry data analyses to prove that the meddies can be followed with remote sensing data for long periods of time. The in situ observations are based on data from an oceanographic cruise, which crossed three meddies, and reanalysis of historical data sets, including RAFOS floats paths. Suggested methodology permitted us to obtain uninterrupted tracks for several meddies for a period from several months to more than 2 years. It was found that the dynamically calm region to the north of the Azores current presents favorable conditions for meddy tracking. The meddy surface signal may become shattered and difficult to follow during interaction with a strong dynamic structures (the Azores current/surface vortexes) or peaking topography. Theoretical considerations support the observations and lead to the conclusion that the dynamic signature of meddies at the sea surface is an intrinsic property of meddy dynamics

Optical Microring Resonators based on ion-implanted LiNbO3 ridge waveguides

The growing interest for Integrated Optics for sensing, telecommunications and even electronics is driving research to find solutions to the new challenges issued by a more and more fast, connected and smart world. This thesis deals with the design, the fabrication and the characterisation of the first prototypes of Microring Resonators realised using ion implanted Lithium Niobate (LiNbO3) ridge waveguides. Optical Resonator is one among the most important devices for all tasks described above. LiNbO3 is the substrate commonly used to fabricate optical modulators thanks to its electro-optic characteristics. Since it is produced in high quantity, good quality and large wafers its price is low compared to other electro-optic substrate. We propose to use ion implantation as fabrication technology because in the other way standard optical waveguides realised in LiNbO3 by Proton Exchange (PE) or metal diffusion do not allow small bending radii, which are necessary to keep the circuit footprint small. We will show in fact that this approach allows to fabricate waveguides on Lithium Niobate that are better than PE or metal diffused waveguides as it allows smaller size devices and tailoring of the refractive index profile controlling the implantation parameters. Moreover, we will show that the ridge technology based on enhanced etching rate via ion implantation produces a waveguide with roughness lower than a dry etched one. Finally it has been assessed a complete technological process for fabrication of Microring Resonator devices in Lithium Niobate by ion implantation and the first prototypes have been produced.

Interactions of inhaled nanoparticles with the alveolar-capillary barrier of the human respiratory tract

In dieser Arbeit wurden zytotoxische Effekte sowie die inflammatorische Reaktionen des distalen respiratorischen Traktes nach Nanopartikelexposition untersucht. Besondere Aufmerksamkeit lag auch auf der Untersuchung unterschiedlicher zellulärer Aufnahmewege von Nanopartikeln wie z.B. Clathrin- oder Caveolae-vermittelte Endozytose oder auch Clathrin- und Caveolae-unabhängige Endozytose (mit möglicher Beteiligung von Flotillinen). Drei unterschiedliche Nanopartikel wurden hierbei gewählt: amorphes Silica (aSNP), Organosiloxan (AmorSil) und Poly(ethyleneimin) (PEI). Alle unterschiedlichen Materialien gewinnen zunehmend an Interesse für biomedizinische Forschungsrichtungen (drug and gene delivery). Insbesondere finden aSNPs auch in der Industrie vermehrt Anwendung, und stellen somit ein ernstzunehmendes Gesundheitsrisiko dar. Dieser wird dadurch zu einem begehrten Angriffsziel für pharmazeutische Verabreichungen von Medikamenten über Nanopartikel als Vehikel aber bietet zugleich auch eine Angriffsfläche für gesundheitsschädliche Nanomaterialien. Aus diesem Grund sollten die gesundheitsschädigenden Risiken, sowie das Schicksal von zellulär aufgenommenen NPs sorgfältig untersucht werden. In vivo Studien an der alveolaren-kapillaren Barriere sind recht umständlich. Aus diesem Grund wurde in dieser Arbeit ein Kokulturmodel benutzt, dass die Alveolar-Kapillare Barrier in vivo nachstellt. Das Model besteht aus dem humanen Lungenepithelzelltyp (z.B. NCI H441) und einem humanen microvasculären Endothelzelltyp (z.B. ISO-HAS-1), die auf entgegengesetzten Seiten eines Transwell-Filters ausgesät werden und eine dichte Barriere ausbilden. Die NP Interaktion mit Zellen in Kokultur wurde mit denen in konventioneller Monokultur verglichen, in der Zellen 24h vor dem Experiment ausgesät werden. Diese Studie zeigt, dass nicht nur die polarisierte Eigenschaft der Zellen in Kokultur sondern auch die unmittelbare Nähe von Epithel und Endothelzelle ausschlaggebend für durch aSNPs verursachte Effekte ist. Im Hinblick auf inflammatorische Marker (sICAM, IL-6, IL8-Ausschüttung), reagiert die Kokultur auf aSNPs empfindlicher als die konventionelle Monokultur, wohingegen die Epithelzellen in der Kokultur auf zytotoxikologischer Ebene (LDH-Ausschüttung) unempfindlicher auf aSNPs reagierten als die Zellen in Monokultur. Aufnahmestudien haben gezeigt, dass die Epithelzellen in Kokultur entschieden weniger NPs aufnehmen. Somit zeigen die H441 in der Kokultur ähnliche epitheliale Eigenschaften einer schützenden Barriere, wie sie auch in vivo zu finden sind. Obwohl eine ausreichende Aufnahme von NPs in H441 in Kokultur erreicht werden konnte, konnte ein Transport von NPs durch die epitheliale Schicht und eine Aufnahme in die endotheliale Schicht mit den gewählten Inkubationszeiten nicht gezeigt werden. Eine Clathrin- oder Caveolae-vermittelte Endozytose von NPs konnte mittels Immunfluoreszenz weder in der Mono- noch in der Kokultur nachgewiesen werden. Jedoch zeigte sich eine Akkumulation von NPs in Flotillin-1 und-2 enthaltende Vesikel in Epithelzellen aus beiden Kultursystemen. Ergebnisse mit Flotillin-inhibierten (siRNA) Epithelzellen, zeigten eine deutlich geringere Aufnahme von aSNPs. Zudem zeigte sich eine eine reduzierte Viabilität (MTS) von aSNP-behandelten Zellen. Dies deutet auf eine Beteiligung von Flotillinen an unbekannten (Clathrin oder Caveolae -unabhängig) Endozytosemechanismen und (oder) endosomaler Speicherung. Zusammenfassend waren die Aufnahmemechanismen für alle untesuchten NPs in konventioneller Monokultur und Kokultur vergleichbar, obwohl sich die Barriereeigenschaften deutlich unterscheiden. Diese Arbeit zeigt deutlich, dass sich die Zellen in Kokultur anders verhalten. Die Zellen erreichen hierbei einen höheren Differenzierungsgrad und eine Zellkommunikation mit anderen relevanten Zelltypen wird ermöglicht. Durch das Einbringen eines dritten relevanten Zelltyps in die Kokultur, des Alveolarmakrophagen (Zelllinie THP-1), welcher die erste Verteidigungsfront im Alveolus bildet, wird diese Aussage weiter bekräftigt. Erste Versuche haben gezeigt, dass die Triplekultur bezüglich ihrer Barriereeigenschaften und IL-8-Ausschüttung sensitiver auf z.B. TNF- oder LPS-Stimulation reagiert als die Kokultur. Verglichen mit konventionellen Monokulturen imitieren gut ausgebildete, multizelluräre Kokulturmodelle viel präziser das zelluläre Zusammenspiel im Körper. Darum liefern Nanopartikelinteraktionen mit dem in vitro-Triplekulturmodel aufschlussreichere Ergebnisse bezüglich umweltbedingter oder pharmazeutischer NP-Exposition in der distalen Lung als es uns bisher möglich war.

Prokaryotic community structure in ultra-slow spreading Southwest Indian Ridge.

The Southwest Indian Ridge segment that extends between 10° and 16° E has the slowest spreading rate of any other oceanic ridge (about 8.4 mm/year). In 2013 during the expedition ANTXXIX/8 seismology, geology, microbiology, heat flow analyses were carried out. Here, no hydrothermal plumes or black smoker systems were found but the results of the survey allowed to identify areas with peculiar characteristics: Area 1 with higher heat flux bsf; Area 2 where in 2002 the presence of hydrothermal emissions was hypothesized (Bach et al., 2002); Area 3 with anomalies of methane, ammonium, sulphide and dissolved inorganic carbon in pore water sediment profiles, and recovery of fauna vents. All these aspects suggest the presence of a hydrothermal circulation. Using Illumina 16S gene tag, statistical tools and phylogenetic trees, I provided a biological proof of the presence of hydrothermal circulation in this ridge segment. At Area 3, alpha and beta diversity indexes showed similarities with those described for venting microbial communities and about 40-70% of the dominant microbial community was found phylogenetically related to clones isolated hydrothermal-driven environments. Although the majority of chemosynthetic environment related taxa were not classified like autotrophic prokaryotes, some of them are key taxa in support of the presence of hydrothermal circulation, since they are partners of consortia or mediate specific reaction typically described for hydrothermal and seep environments, or are specialized organisms in exploiting labile organic substrates. Concluding, these results are remarkable because support the importance of ultra slow spreading ridge systems in contributing to global geochemical cycles and larval dispersion of vent fauna.

Alveolar inflammation in cystic fibrosis

In infected lungs of the cystic fibrosis (CF) patients, opportunistic pathogens and mutated cystic fibrosis transmembrane conductance regulator protein (CFTR) contribute to chronic airway inflammation that is characterized by neutrophil/macrophage infiltration, cytokine release and ceramide accumulation. We sought to investigate CF lung inflammation in the alveoli.

An in vitro triple cell co-culture model with primary cells mimicking the human alveolar epithelial barrier

A triple cell co-culture model was recently established by the authors, consisting of either A549 or 16HBE14o- epithelial cells, human blood monocyte-derived macrophages and dendritic cells, which offers the possibility to study the interaction of xenobiotics with those cells. The 16HBE14o- containing co-culture model mimics the airway epithelial barrier, whereas the A549 co-cultures mimic the alveolar type II-like epithelial barrier. The goal of the present work was to establish a new triple cell co-culture model composed of primary alveolar type I-like cells isolated from human lung biopsies (hAEpC) representing a more realistic alveolar epithelial barrier wall, since type I epithelial cells cover >93% of the alveolar surface. Monocultures of A549 and 16HBE14o- were morphologically and functionally compared with the hAEpC using laser scanning microscopy, as well as transmission electron microscopy, and by determining the epithelial integrity. The triple cell co-cultures were characterized using the same methods. It could be shown that the epithelial integrity of hAEpC (mean ± SD, 1180 ± 188 Ω cm(2)) was higher than in A549 (172 ± 59 Ω cm(2)) but similar to 16HBE14o- cells (1469 ± 156 Ω cm(2)). The triple cell co-culture model with hAEpC (1113 ± 30 Ω cm(2)) showed the highest integrity compared to the ones with A549 (93 ± 14 Ω cm(2)) and 16HBE14o- (558 ± 267 Ω cm(2)). The tight junction protein zonula occludens-1 in hAEpC and 16HBE14o- were more regularly expressed but not in A549. The epithelial alveolar model with hAEpC combined with two immune cells (i.e. macrophages and dendritic cells) will offer a novel and more realistic cell co-culture system to study possible cell interactions of inhaled xenobiotics and their toxic potential on the human alveolar type I epithelial wall.

Analysis of new bone formation induced by periosteal distraction in a rat calvarium model

Background: A controlled, gradual distraction of the periosteum is expected to result in the formation of new bone. Purpose: This study was designed to estimate the possibility of new bone formation by periosteal distraction in a rat calvarium model. Material and Methods: Sixteen animals were subjected to a 7-day latency period and distraction rate at 0.4 mm/24 hours for 10 days. Two experimental groups with seven rats each were killed at 10 and 20 days of consolidation period and analyzed by means of microcomputed tomography, histologically and histomorphometry. Results: In the central regions underneath the disk device, signs of both bone apposition and bone resorption were observed. Peripheral to the disc, new bone was consistently observed. This new bone was up to two and three times thicker than the original bone after a 10- and 20-day consolidation period, respectively. Signs of ongoing woven bone formation indicated that the stimulus for new bone formation was still present. There were no statistically significant differences regarding bone density, bone volume, and total bone height between the two groups. Conclusion: The periosteal distraction model in the rat calvarium can stimulate the formation of considerable amounts of new bone.

Periosteal Distraction Osteogenesis and Barrier Membrane Application: An Experimental Study in the Rat Calvaria

Background: Distraction of the periosteum results in the formation of new bone in the gap between the periosteum and the original bone. We postulate that the use of a barrier membrane would be beneficial for new bone formation in periosteal distraction. Methods: To selectively influence the contribution of the periosteum, a distraction plate with perforations was used alone or covered by a collagen barrier membrane. All animals were subjected to a 7-day latency period and a 10-day distraction period with a rate of 0.1 mm/day. Four animals per group with or without a barrier membrane were sacrificed at 2, 4, and 6 weeks after the end of the distraction. The height of new bone generated relative to the areas bound by the parent bone and the periosteum was determined by histomorphometric methods. Results: New bone was found in all groups. At the periphery of the distraction plate, significant differences in bone height were found between the hinge and the distraction screw for the group without barrier membrane at 2 weeks (0.39 ± 0.19 mm) compared to 4 weeks (0.84 ± 0.44 mm; P = 0.002) and 6 weeks (1.06 ± 0.39 mm; P = 0.004). Differences in maximum bone height with and without a barrier membrane were observed laterally to the distraction plate at 2 weeks (1.22 ± 0.64 versus 0.55 ± 0.14 mm; P = 0.019) and 6 weeks (1.61 ± 0.56 versus 0.73 ± 0.33 mm; P = 0.003) of the consolidation period. Conclusion: Within the limitations of the present study, the application of a barrier membrane may be considered beneficial for new bone formation induced by periosteal distraction.

Early alveolar bone grafting has a negative effect on maxillary dental arch dimensions of pre-school children with complete unilateral cleft lip and palate

To evaluate maxillary dental arch dimensions in pre-school children with a complete unilateral cleft lip and palate (CUCLP) after early alveolar bone grafting.

Local strain distribution in real three-dimensional alveolar geometries

Mechanical ventilation is not only a life saving treatment but can also cause negative side effects. One of the main complications is inflammation caused by overstretching of the alveolar tissue. Previously, studies investigated either global strains or looked into which states lead to inflammatory reactions in cell cultures. However, the connection between the global deformation, of a tissue strip or the whole organ, and the strains reaching the single cells lining the alveolar walls is unknown and respective studies are still missing. The main reason for this is most likely the complex, sponge-like alveolar geometry, whose three-dimensional details have been unknown until recently. Utilizing synchrotron-based X-ray tomographic microscopy, we were able to generate real and detailed three-dimensional alveolar geometries on which we have performed finite-element simulations. This allowed us to determine, for the first time, a three-dimensional strain state within the alveolar wall. Briefly, precision-cut lung slices, prepared from isolated rat lungs, were scanned and segmented to provide a three-dimensional geometry. This was then discretized using newly developed tetrahedral elements. The main conclusions of this study are that the local strain in the alveolar wall can reach a multiple of the value of the global strain, for our simulations up to four times as high and that thin structures obviously cause hotspots that are especially at risk of overstretching.

Relative Contributions of Osteogenic Tissues to New Bone Formation in Periosteal Distraction Osteogenesis: Histological and Histomorphometrical Evaluation in a Rat Calvaria

Background: The relative contributions of different, potential factors to new bone formation in periosteal distraction osteogenesis are unknown. Purpose: The aim of the present study was to assess the influence of original bone and periosteum on bone formation during periosteal distraction osteogenesis in a rat calvarial model by means of histology and histomorphometry. Methods: A total of 48 rats were used for the experiment. The contribution of the periosteum was assessed by either intact or incised periosteum or an occlusive versus a perforated distraction plate. The cortical bone was either left intact or perforated. Animals were divided in eight experimental groups considering the three possible treatment modalities. All animals were subjected to a 7-day latency period, a 10-day distraction period and a 7-day consolidation period. The newly formed bone was analyzed histologically and histomorphometrically. Results: New, mainly woven bone was found in all groups. Differences in the maximum height of new bone were observed and depended on location. Under the distraction plate, statistically significant differences in maximum bone height were found between the group with perforations in both cortical bone and distraction plate and the group without such perforations. Conclusions: If the marrow cavities were not opened, the contribution to new bone formation was dominant from the periosteum. If the bone perforations opened the marrow cavities, a significant contribution to new bone formation originated from the native bone.

Microfluidic wound-healing assay to assess the regenerative effect of HGF on wounded alveolar epithelium

We present a microfluidic epithelial wound-healing assay that allows characterization of the effect of hepatocyte growth factor (HGF) on the regeneration of alveolar epithelium using a flow-focusing technique to create a regular wound in the epithelial monolayer. The phenotype of the epithelial cell was characterized using immunostaining for tight junction (TJ) proteins and transmission electron micrographs (TEMs) of cells cultured in the microfluidic system, a technique that is reported here for the first time. We demonstrate that alveolar epithelial cells cultured in a microfluidic environment preserve their phenotype before and after wounding. In addition, we report a wound-healing benefit induced by addition of HGF to the cell culture medium (19.2 vs. 13.5 μm h(-1) healing rate).

Provenance signature of a forearc basin modified by spreading ridge subduction: Detrital zircon geochronology and detrital modes from the Paleogene Arkose Ridge Formation, southern Alaska

Upper Paleocene–Eocene boulder conglomerate, cross-stratified sandstone, and laminated carbonaceous mudstone of the Arkose Ridge Formation exposed in the southern Talkeetna Mountains record fluvial-lacustrine deposition proximal to the volcanic arc in a forearc basin modified by Paleogene spreading ridge subduction beneath southern Alaska. U-Pb ages of detrital zircon grains and modal analyses were obtained from stratigraphic sections spanning the 2,000 m thick Arkose Ridge Formation in order to constrain the lithology, age, and location of sediment sources that provided detritus. Detrital modes from 24 conglomerate beds and 54 sandstone thin sections aredominated by plutonic and volcanic clasts and plagioclase feldspar with minor quartz, schist, hornblende, argillite, and metabasalt. Westernmost sandstone and conglomerate strata contain <5% volcanic clasts whereas easternmost sandstone and conglomerate strata contain 40 to >80% volcanic clasts. Temporally, eastern sandstones andconglomerates exhibit an upsection increase in volcanic detritus from <40 to >80% volcanic clasts. U-Pb ages from >1400 detrital zircons in 15 sandstone samples reveal three main populations: late Paleocene–Eocene (60-48 Ma; 16% of all grains), Late Cretaceous–early Paleocene (85–60 Ma; 62%) and Jurassic–Early Cretaceous (200–100 Ma; 12%). A plot of U/Th vs U-Pb ages shows that >97% of zircons are <200 Ma and>99% of zircons have <10 U/Th ratios, consistent with mainly igneous source terranes. Strata show increased enrichment in late Paleocene–Eocene detrital zircons from <2% in the west to >25% in the east. In eastern sections, this younger age population increases temporally from 0% in the lower 50 m of the section to >40% in samples collected >740 m above the base. Integration of the compositional and detrital geochronologic data suggests: (1) Detritus was eroded mainly from igneous sources exposed directly north of the Arkose Ridge Formation strata, mainly Jurassic–Paleocene plutons and Paleocene–Eocenevolcanic centers. Subordinate metamorphic detritus was eroded from western Mesozoic low-grade metamorphic sources. Subordinate sedimentary detritus was eroded from eastern Mesozoic sedimentary sources. (2) Eastern deposystems received higher proportions of juvenile volcanic detritus through time, consistent with construction of adjacent slab-window volcanic centers during Arkose Ridge Formation deposition. (3)Western deposystems transported detritus from Jurassic–Paleocene arc plutons that flank the northwestern basin margin. (4) Metasedimentary strata of the Chugach accretionaryprism, exposed 20-50 km south of the Arkose Ridge Formation, did not contribute abundant detritus. Conventional provenance models predict reduced input of volcanic detritus to forearc basins during exhumation of the volcanic edifice and increasing exposure ofsubvolcanic plutons (Dickinson, 1995; Ingersoll and Eastmond, 2007). In the forearc strata of these conventional models, sandstone modal analyses record progressive increases upsection in quartz and feldspar concomitant with decreases in lithic grains, mainly volcanic lithics. Additionally, as the arc massif denudes through time, theyoungest detrital U-Pb zircon age populations become significantly older than the age of forearc deposition as the arc migrates inboard or ceases magmatism. Westernmost strata of the Arkose Ridge Formation are consistent with this conventional model. However, easternmost strata of the Arkose Ridge Formation contain sandstone modes that record an upsection increase in lithic grains accompanied by a decrease in quartz and feldspar, and detrital zircon age populations that closely match the age of deposition. This deviation from the conventional model is due to the proximity of the easternmost strata to adjacent juvenile volcanic rocks emplaced by slab-window volcanic processes. Provenance data from the Arkose Ridge Formation show that forearc basins modified by spreading ridge subduction may record upsection increases in non-arc, syndepositional volcanic detritusdue to contemporaneous accumulation of thick volcanic sequences at slab-window volcanic centers. This change may occur locally at the same time that other regions of the forearc continue to receive increasing amounts of plutonic detritus as the remnant arc denudes, resulting in complex lateral variations in forearc basin petrofacies and chronofacies.