Geochemistry, petrogenesis and tectonic setting of ophiolites and mafic-ultramafic complexes in the Northeastern Aegean Region

In this study two ophiolites and a mafic-ultramafic complexes of the northeastern Aegean Sea, Greece, have been investigated to re-evaluate their petrogenetic evolution and tectonic setting. These complexes are: the mafic-ultramafic complex of Lesvos Island and the ophiolites of Samothraki Island and the Evros area. In order to examine these complexes in detail whole-rock major- and trace-elements as well as Sr and Nd isotopes, and minerals were analysed and U-Pb SHRIMP ages on zircons were determined. The mafic-ultramafic complex of Lesvos Island consists of mantle peridotite thrusted over a tectonic mélange containing metasediments, metabasalts and a few metagabbros. This succession had previously been interpreted as an ophiolite of Late Jurassic age. The new field and geochemical data allow a reinterpretation of this complex as representing an incipient continental rift setting that led to the subsequent formation of the Meliata-Maliac-Vardar branches of Neotethys in Upper Permian times (253 ± 6 Ma) and the term “Lesvos ophiolite” should be abandoned. With proceeding subduction and closure of the Maliac Ocean in Late Jurassic times (155 Ma) the Lesvos mafic-ultramafic complex was obducted. Zircon ages of 777, 539 and 338 Ma from a gabbro strongly suggest inheritance from the intruded basement and correspond to ages of distinct terranes recently recognized in the Hellenides (e.g. Florina terrane). Geochemical similar complexes which contain rift associations with Permo-Triassic ages can be found elsewhere in Greece and Turkey, namely the Teke Dere Thrust Sheet below the Lycian Nappes (SW Turkey), the Pindos subophiolitic mélange (W Greece), the Volcanosedimentary Complex on Central Evia Island (Greece) and the Karakaya Complex (NW Turkey). This infers that the rift-related rocks from Lesvos belong to an important Permo-Triassic rifting episode in the eastern Mediterranean. The ‘in-situ’ ophiolite of Samothraki Island comprises gabbros, sparse dykes and basalt flows as well as pillows cut by late dolerite dykes and had conventionally been interpreted as having formed in an ensialic back-arc basin. The results of this study revealed that none of the basalts and dolerites resemble mid-ocean ridge or back-arc basin basalts thus suggesting that the Samothraki ophiolite cannot represent mature back-arc basin crust. The age of the complex is regarded to be 160 ± 5 Ma (i.e. Oxfordian; early Upper Jurassic), which precludes any correlation with the Lesvos mafic-ultramafic complex further south (253 ± 6 Ma; Upper Permian). Restoration of the block configuration in NE Greece, before extensional collapse of the Hellenic hinterland and exhumation of the Rhodope Metamorphic Core Complex (mid-Eocene to mid-Miocene), results in a continuous ophiolite belt from Guevgueli in the NW to Samothraki in the SE, thus assigning the latter to the Innermost Hellenic Ophiolite Belt. In view of the data of this study, the Samothraki ophiolite represents a rift propagation of the Sithonia ophiolite spreading ridge into the Chortiatis calc-alkaline arc. The ophiolite of the Evros area consists of a plutonic sequence comprising cumulate and non-cumulate gabbros with plagiogranite veins, and an extrusive sequence of basalt dykes, massive and pillow lavas as well as pyroclastic rocks. Furthermore, in the Rhodope Massif tectonic lenses of harzburgites and dunites can be found. All rocks are spatially separated. The analytical results of this study revealed an intra-oceanic island arc setting for the Evros ophiolitic rocks. During late Middle Jurassic times (169 ± 2 Ma) an intra-oceanic arc has developed above a northwards directed intra-oceanic subduction zone of the Vardar Ocean in front of the Rhodope Massif. The boninitic, island arc tholeiitic and calc-alkaline rocks reflect the evolution of the Evros island arc. The obduction of the ophiolitic rocks onto the Rhodope basement margin took place during closure of the Vardar ocean basins. The harzburgites and dunites of the Rhodope Massif are strongly depleted and resemble harzburgites from recent oceanic island arcs. After melt extraction they underwent enrichment processes by percolating melts and fluids from the subducted slab. The relationship of the peridotites and the Evros ophiolite is still ambiguous, but the stratigraphic positions of the peridotites and the ophiolitic rocks indicate separated origin. The harzburgites and dunites most probably represent remnants of the mantle wedge of the island arc of the Rhodope terrane formed above subducted slab of the Nestos Ocean in late Middle Jurassic times. During collision of the Thracia terrane with the Rhodope terrane thrusting of the Rhodope terrane onto the Thracia terrane took place, whereas the harzburgites and dunites were pushed between the two terranes now cropping out on top of the Thracia terrane of the Rhodope Massif.

Mesozoic fold structure of the Otago and Alpine Schist Belt and its implications on the tectonic evolution of South Island, New Zealand

Erneute Untersuchungen der mesozoischen Faltenstruktur des Otago Schiefergürtels, Südinsel, Neuseeland, zeigen, dass diese aus zwei aufeinander folgenden, ähnlichen, asymmetrischen, offenen bis mäßig engen Großfaltengenerationen im km- Größenbereich besteht anstatt aus den vorher angenommenen Decken- oder Halbfalten. Hauptproblem der Großfaltenstruktur sind Zonen von durchgreifender Boudinage, die in der Nähe der Großfaltenscharniere entstanden sind. Vorherige Bearbeiter deuteten diese Zonen als 'starke Verformungszonen' oder Überschiebungszonen. Diese Arbeit zeigt, dass in diesen Zonen nur durch die asymmetrische Faltung die unteren liegenden Schenkel der Großfalten boudiniert und somit häufig die ansonsten typischen Faltenstrukturen des liegenden Schenkels einer symmetrischen Faltung überprägt wurden. Ein weiteres Problem dieser mesozoischen Großfaltenstruktur ist die Überprägung einer Faltengeneration auf eine frühere. Weil die Verkürzungsrichtung der überprägenden Faltengeneration nicht subparallel zur älteren Faltenachse ist, sondern einen Winkel von rund 30 Grad einschließt, ist ein Wechsel von orthogonalen zu koaxialen Interferenzmustern der Kleinfalten beobachtbar. Folglich ist die Orientierung der Scheitellinie einer überprägenden und überprägten Kleinfalte nicht unbedingt subparallel zur Orientierung der Faltenachse der Großfalte trotz zylindrischer Faltung. Im letzten Teil dieser Arbeit wird die Überprägung der mesozoischen Großfaltenstruktur durch das känozoisch entstandene, transpressionale Alpine Störungssystem, das einen zweiseitigen Falten- und Überschiebungsgürtel im Otago und im Nordwesten anschließenden Alpinen Schiefergürtel bildet, beschrieben.

Swarm constructability: designing through embedded tectonic behaviors in swarm robotic systems

Con questa tesi di laurea si muovono i primi passi di una ricerca applicata finalizzata alla costruzione-deposizione di materiale da parte di sciami di mini-robot dal comportamento indipendente che si coordinano tramite segnali lasciati e rilevati nell’ambiente in cui si muovono. Lo sviluppo di tecniche di progettazione e fabbricazione digitale ha prodotto un aumento nel grado di interconnessione tra tecnologia e design, dunque, di nuove possibilità tettoniche. Le relazioni tettoniche tradizionali stanno infatti subendo una trasformazione radicale, potendo essere esplicitamente informate e dunque mediate attraverso gli strumenti digitali dall’ideazione alla produzione. Questa mediazione informata del contenuto tettonico (che opera costantemente) è distintivo di un approccio material-based alla progettazione che aumenta l’integrazione tra struttura, materia e forma entro le tecnologie di fabbricazione (R.Oxman). Dei numerosi processi di fabbricazione per l’architettura che si servono di tecnologia robotica, pochi sono capaci di superare la logica gerarchica, rigida e lineare-sequenziale che serve di fatto agli obiettivi di automazione ed ottimizzazione. La distribuzione di forme di intelligenza semplificata ad un numero elevato di unità robot è quindi qui proposta come alternativa al modello appena descritto. Incorporando semplici decisioni di carattere architettonico negli agenti-robot che costituiscono il sistema distribuito di entità autonome, la loro interazione e le decisioni prese individualmente producono comportamento collettivo e l’integrazione delle suddette relazioni tettoniche. Nello sviluppo del progetto, si è fatto così riferimento a modelli comportamentali collettivi (di sciame) osservabili in specie comunitarie che organizzano strutture materiali -come termiti e vespe- ed in organismi semplici -come le muffe cellulari della specie Physarum polycephalum. Per queste specie biologiche il processo di costruzione non dipende da un ‘piano generale’ ma è guidato esclusivamente da azioni dei singoli individui che comunicano lasciando tracce chimiche nell’ambiente e modificano il loro comportamento rilevando le tracce lasciate dagli altri individui. A questo scopo, oltre alle simulazioni in digitale, è stato indispensabile sviluppare dei prototipi funzionali di tipo fisico, ovvero la realizzazione di mini-robot dal movimento indipendente, in grado di coordinarsi tra loro tramite segnali lasciati nell’ambiente e capaci di depositare materiale.

Quantitative analysis of extracapsular extension of metastatic lymph nodes and its significance in radiotherapy planning in head and neck squamous cell carcinoma

We performed a histopathologic analysis to assess the extent of the extracapsular extension (ECE) beyond the capsule of metastatic lymph nodes (LN) in head and neck cancer to determine appropriate clinical target volume (CTV) expansions.

Expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases

BACKGROUND: Inflammatory lung diseases are a major morbidity factor in children. Therefore, novel strategies for early detection of inflammatory lung diseases are of high interest. Bacterial lipopolysaccharide (LPS) is recognized via Toll-like receptors and CD14. CD14 exists as a soluble (sCD14) and membrane-associated (mCD14) protein, present on the surface of leukocytes. Previous studies suggest sCD14 as potential marker for inflammatory diseases, but their potential role in pediatric lung diseases remained elusive. Therefore, we examined the expression, regulation and significance of sCD14 and mCD14 in pediatric lung diseases. METHODS: sCD14 levels were quantified in serum and bronchoalveolar lavage fluid (BALF) of children with infective (pneumonia, cystic fibrosis, CF) and non-infective (asthma) inflammatory lung diseases and healthy control subjects by ELISA. Membrane CD14 expression levels on monocytes in peripheral blood and on alveolar macrophages in BALF were quantified by flow cytometry. In vitro studies were performed to investigate which factors regulate sCD14 release and mCD14 expression. RESULTS: sCD14 serum levels were specifically increased in serum of children with pneumonia compared to CF, asthma and control subjects. In vitro, CpG induced the release of sCD14 levels in a protease-independent manner, whereas LPS-mediated mCD14 shedding was prevented by serine protease inhibition. CONCLUSIONS: This study demonstrates for the first time the expression, regulation and clinical significance of soluble and membrane CD14 receptors in pediatric inflammatory lung diseases and suggests sCD14 as potential marker for pneumonia in children.

Significance of Periodontal Risk Assessment in the recurrence of periodontitis and tooth loss

Aim: To investigate the association of the Periodontal Risk Assessment (PRA) model categories with periodontitis recurrence and tooth loss during supportive periodontal therapy (SPT) and to explore the role of patient compliance. Material and Methods: In a retrospective cohort, PRA was performed for 160 patients after active periodontal therapy (APT) and after 9.5 ± 4.5 years of SPT. The recurrence of periodontitis and tooth loss were analysed according to the patient's risk profile (low, moderate or high) after APT and compliance with SPT. The association of risk factors with tooth loss and recurrence of periodontitis was investigated using logistic regression analysis. Results: In 18.2% of patients with a low-risk profile, in 42.2% of patients with a moderate-risk profile and in 49.2% of patients with a high-risk profile after APT, periodontitis recurred. During SPT, 1.61 ± 2.8 teeth/patient were lost. High-risk profile patients lost significantly more teeth (2.59 ± 3.9) than patients with moderate- (1.02 ± 1.8) or low-risk profiles (1.18 ± 1.9) (Kruskal–Wallis test, p=0.0229). Patients with erratic compliance lost significantly (Kruskal–Wallis test, p=0.0067) more teeth (3.11 ± 4.5) than patients compliant with SPT (1.07 ± 1.6). Conclusions: In multivariate logistic regression analysis, a high-risk patient profile according to the PRA model at the end of APT was associated with recurrence of periodontitis. Another significant factor for recurrence of periodontitis was an SPT duration of more than 10 years.

Prognostic significance of apoptotic cell death in bladder cancer: a tissue microarray study on 179 urothelial carcinomas from cystectomy specimens

To assess the prognostic significance of apoptosis related markers in bladder cancer.

Randomization in clinical trials in orthodontics: its significance in research design and methods to achieve it

Randomization is a key step in reducing selection bias during the treatment allocation phase in randomized clinical trials. The process of randomization follows specific steps, which include generation of the randomization list, allocation concealment, and implementation of randomization. The phenomenon in the dental and orthodontic literature of characterizing treatment allocation as random is frequent; however, often the randomization procedures followed are not appropriate. Randomization methods assign, at random, treatment to the trial arms without foreknowledge of allocation by either the participants or the investigators thus reducing selection bias. Randomization entails generation of random allocation, allocation concealment, and the actual methodology of implementing treatment allocation randomly and unpredictably. Most popular randomization methods include some form of restricted and/or stratified randomization. This article introduces the reasons, which make randomization an integral part of solid clinical trial methodology, and presents the main randomization schemes applicable to clinical trials in orthodontics.

Prognostic significance of CD8+ T lymphocytes in breast cancer depends upon both oestrogen receptor status and histological grade

Results of previous studies on the influence of tumour infiltrating lymphocytes on prognosis of women with breast cancer have been mixed. This study re-evaluates the role of tumour-infiltrating lymphocytes as a prognostic marker in women with breast cancer.

Using the Natural Period of a Structure as an Indicator of the Significance of Second-Order Effects

This study investigates the feasibility of predicting the momentamplification in beam-column elements of steel moment-resisting frames using the structure's natural period. Unlike previous methods, which perform moment-amplification on a story-by-story basis, this study develops and tests two models that aim to predict a global amplification factor indicative of the largest relevant instance of local moment amplification in the structure. To thisend, a variety of two-dimensional frames is investigated using first and secondorder finite element analysis. The observed moment amplification is then compared with the predicted amplification based on the structure's natural period, which is calculated by first-order finite element analysis. As a benchmark, design moment amplification factors are calculated for each story using the story stiffness approach, and serve to demonstrate the relativeconservatism and accuracy of the proposed models with respect to current practice in design. The study finds that the observed moment amplification factors may vastly exceed expectations when internal member stresses are initially very small. Where the internal stresses are small relative to the member capacities, thesecases are inconsequential for design. To qualify the significance of the observed amplification factors, two parameters are used: the second-order moment normalized to the plastic moment capacity, and the combined flexural and axial stress interaction equations developed by AISC

Purification, cDNA structure and biological significance of a single insulin-like growth factor-binding domain protein (SIBD-1) identified in the hemocytes of the spider Cupiennius salei

Cupiennius salei single insulin-like growth factor-binding domain protein (SIBD-1), which exhibits an IGFBP N-terminal domain-like profile, was identified in the hemocytes of the spider C. salei. SIBD-1 was purified by RP-HPLC and the sequence determined by a combination of Edman degradation and 5'-3'- RACE PCR. The peptide (8676.08 Da) is composed of 78 amino acids, contains six intrachain disulphide bridges and carries a modified Thr residue at position 2. SIBD-1 mRNA expression was detected by quantitative real-time PCR mainly in hemocytes, but also in the subesophageal nerve mass and muscle. After infection, the SIBD-1 content in the hemocytes decreases and, simultaneously, the temporal SIBD-1 expression seems to be down-regulated. Two further peptides, SIBD-2 and IGFBP-rP1, also exhibiting IGFBP N-terminal domain variants with unknown functions, were identified on cDNA level in spider hemocytes and venom glands. We conclude that SIBD-1 may play an important role in the immune system of spiders.