Geological solutions concluded by petroleum geochemical data in Western Greece

Τα προηγούμενα χρόνια έχει πραγματοποιηθεί μια λεπτομερής γεωχημική μελέτη πετρελαίου στη Δυτική Ελλάδα. Εντοπίστηκαν αρκετοί ορίζοντες πιθανών μητρικών πετρωμάτων πετρελαίου, προσδιορίστηκε το παράθυρο πετρελαίου στις πιο σημαντικές υπολεκάνες, ενώ από τη μελέτη συσχετισμού πετρελαίων προσδιορίστηκαν οι διαφορετικές ομάδες πετρελαίου της περιοχής, που έχουν παραχθεί από τα διαφορετικά μητρικά πετρώματα υδρογονανθράκων. Τα αποτελέσματα αυτά είναι πολύ σημαντικά και απαραίτητα για την έρευνα πετρελαίου στην περιοχή. Όμως, εκτός από αυτά τα δεδομένα, κάποιες επιπλέον γεωχημικές παρατηρήσεις μπορεί να αποβούν εξίσου σημαντικές στην επίλυση ορισμένων γεωλογικών προβλημάτων της Δυτικής Ελλάδας.- Ένα πολύ σημαντικό πρόβλημα είναι η απόθεση και διατήρηση του οργανικού υλικού στις λεκάνες της Δυτικής Ελλάδας.- Η δολομιτίωση σε συνάρτηση με τη γένεση πετρελαίου είναι ένα πρόβλημα.- Ένα άλλο θέμα είναι ο υπολογισμός του πάχους που διαβρώθηκε από τους υπερκείμενους σχηματισμούς.- Ο προσδιορισμός της παλαιογεωθερμικής βαθμίδας είναι επίσης πολύ σημαντικός.Οι δύο τελευταίοι παράμετροι είναι απόλυτα απαραίτητοι για τον προσδιορισμό της ωριμότητας του οργανικού υλικού.Η μελέτη όλων των παραπάνω παραμέτρων συμπληρώνει τη γεωχημική μελέτη της Δυτικής Ελλάδας, και σε συνδυασμό με άλλες γεωλογικές μελέτες μπορεί να δώσει λύσεις σε προβλήματα που σχετίζονται με την έρευνα υδρογονανθράκων στην περιοχή.A detailed petroleum geochemical study has been performed in the previous years in the Western Greece. Several source rock horizons have been identified, the oil window has been calculated for the most significant sub-basins and the oil correlation study has distinguished the different oil groups of the area, generated from different hydrocarbon sources. These results are very significant and useful for the oil exploration. But, further to these, some more geochemical observations can also be very important on solving some geological problems of the area.- A major problem is the deposition and preservation of the organic matter in the Western Greece.- The dolomitization in relation with the oil generation is also an issue.- Another issue is the calculation of the eroded overburden formations thickness.- The Paleogeothermal gradient determination is also very important.The last two parameters are absolutely necessary for organic matter maturity calculations.The study of all the above parameters completes the geochemical study of the Western Greece, and in relation with other geological studies can provide solutions in the petroleum exploration of the area

Modelling Complex Draft-Tube Flows using Near-Wall Turbulence Closures

This paper presents a finite-volume method for simulating flows through complex hydroturbine draft-tube configurations using near-wall turbulence closures. The method employs the artificial-compressibility pressure-velocity coupling approach in conjunction with multigrid acceleration for fast convergence on very fine grids. Calculations are carried out for a draft tube with two downstream piers on a computational mesh consisting of 1.2x10{sup 6} nodes. Comparisons of the computed results with measurements demonstrate the ability of the method to capture most experimental trends with reasonable accuracy. Calculated three-dimensional particle traces reveal very complex flow features in the vicinity of the piers, including horse-shoe longitudinal vortices and and regions of flow reversal

Citalopram-mediated anxiolysis and differing neurobiological responses in both sexes of a genetic model of depression

Disorders such as depression and anxiety exhibit strong sex differences in their prevalence and incidence, with women also differing from men in their response to antidepressants. Furthermore, receptors for corticotrophin releasing hormone (CRHR1) and arginine vasopressin receptor subtype 1b (AVPR1b) are known to contribute to the regulation of mood and anxiety. In the present study, we compared the anxiety profile and CRHR1 and AVPR1b expression levels in control Sprague–Dawley (SD) rats and rats of the SD-derived Flinders Sensitive Line (FSL), a genetic model of depression. Additionally, given the apparent sex differences in the therapeutic efficacy of antidepressants and because antidepressants are commonly used to treat comorbid anxiety and depressive symptoms, we assessed whether the anxiolytic effects of an antidepressant occur in a sex-dependent manner. Male and female FSL rats were treated with citalopram 10 mg/kg once daily for 14 days and were then tested in the open field and the elevated plus maze paradigms. Upon completion of the behavioural analysis, AVPR1b and CRHR1 expression levels were monitored in the hypothalamus and the prefrontal cortex (PFC) using Western blotting. According to our results, male FSL rats were more anxious than control SD rats, a difference abolished by citalopram treatment. Baseline anxiety levels were similar in female FSL and SD rats, and citalopram further reduced anxiety in female FSL rats. Importantly, whereas citalopram altered AVPR1b expression in the hypothalamus of male FSL rats, its actions on this parameter were restricted to the PFC in female FSL rats. In both sexes of FSL rats, citalopram did not alter CRHR1 expression in either the hypothalamus or PFC. Our results demonstrate that antidepressant treatment reduces anxiety levels in FSL rats of both sexes: the magnitude of treatment effect was related to the starting baseline level of anxiety and the antidepressant elicited sexually differentiated neurobiological responses in specific brain regions.This research was partly supported through a German-Greek Academic Exchange Programme (DAAD-IKYDA: D/04/42259), an IBRO studentship to N.K., and a Max Planck Society fellowship to I.S

Chronic stress and glucocorticoids: from neuronal plasticity to neurodegeneration

Stress and stress hormones, glucocorticoids (GCs), exert widespread actions in central nervous system, ranging from the regulation of gene transcription, cellular signaling, modulation of synaptic structure, and transmission and glial function to behavior. Their actions are mediated by glucocorticoid and mineralocorticoid receptors which are nuclear receptors/transcription factors. While GCs primarily act to maintain homeostasis by inducing physiological and behavioral adaptation, prolonged exposure to stress and elevated GC levels may result in neuro- and psychopathology. There is now ample evidence for cause-effect relationships between prolonged stress, elevated GC levels, and cognitive and mood disorders while the evidence for a link between chronic stress/GC and neurodegenerative disorders such as Alzheimer's (AD) and Parkinson's (PD) diseases is growing. This brief review considers some of the cellular mechanisms through which stress and GC may contribute to the pathogenesis of AD and PD.The work was supported by Grants “PTDC/SAU-NMC/113934/2009,” funded by FCT, Portuguese Foundation for Science and Technology, and project DoIT, Desenvolvimento e Operacionalização da Investigação de Translação (N° do projeto 13853), funded by Fundo Europeu de Desenvolvimento Regional (FEDER) through the Programa Operacional Fatores de Competitividade (POFC). In addition, this work was also cofinanced by European Union FP7 Project SwitchBox (Nuno Sousa, Osborne F. X. Almeida) and the Portuguese North Regional Operational Program (ON.2 – O Novo Norte) under the National Strategic Reference Framework (QREN), through the European Regional Development Fund (FEDER). Sheela Vyas acknowledges grant support from Foundation de France, Physiopathology of Parkinson, France Parkinson and ANR Grant “ParkStrim” N° 13-BSV1-0013-02. Work in FT research group was supported by Agence Nationale de la Recherche (TIMMS and StressPsyco) and Fondation pour la Recherche Médicale, Grant no. DEQ20140329552

The amyloidogenic potential and behavioral correlates of stress

Observations of elevated basal cortisol levels in Alzheimer's disease (AD) patients prompted the hypothesis that stress and glucocorticoids (GC) may contribute to the development and/or maintenance of AD. Consistent with that hypothesis, we show that stress and GC provoke misprocessing of amyloid precursor peptide in the rat hippocampus and prefrontal cortex, resulting in increased levels of the peptide C-terminal fragment 99 (C99), whose further proteolytic cleavage results in the generation of amyloid-beta (Abeta). We also show that exogenous Abeta can reproduce the effects of stress and GC on C99 production and that a history of stress strikingly potentiates the C99-inducing effects of Abeta and GC. Previous work has indicated a role for Abeta in disruption of synaptic function and cognitive behaviors, and AD patients reportedly show signs of heightened anxiety. Here, behavioral analysis revealed that like stress and GC, Abeta administration causes spatial memory deficits that are exacerbated by stress and GC; additionally, Abeta, stress and GC induced a state of hyperanxiety. Given that the intrinsic properties of C99 and Abeta include neuroendangerment and behavioral impairment, our findings suggest a causal role for stress and GC in the etiopathogenesis of AD, and demonstrate that stressful life events and GC therapy can have a cumulative impact on the course of AD development and progression.CC and IS were supported by stipends from the Max Planck Society and EU Marie Curie Training Fellowships (at University College London, UK). The collaboration between the German and Portuguese laboratories was supported through the German–Portuguese Luso-Alemas Program (DAAD/GRICES). This study was conducted within the framework of the EU-supported integrated project ‘CRESCENDO’ (Contract FP6-018652)

Tau protein is essential for stress-induced brain pathology

Exposure to chronic stress is frequently accompanied by cognitive and affective disorders in association with neurostructural adaptations. Chronic stress was previously shown to trigger Alzheimer's-like neuropathology, which is characterized by Tau hyper-phosphorylation and missorting into dendritic spines followed by memory deficits. Here, we demonstrate that stress-driven hippocampal deficits in wild-type mice are accompanied by synaptic missorting of Tau and enhanced Fyn/GluN2B-driven synaptic signaling. In contrast, mice lacking Tau [Tau knockout (Tau-KO) mice] do not exhibit stress-induced pathological behaviors and atrophy of hippocampal dendrites or deficits of hippocampal connectivity. These findings implicate Tau as an essential mediator of the adverse effects of stress on brain structure and function.We thank Dr. Peter Davies (Albert Einstein College) for the PHF1 antibody. This work was funded by Portuguese Foundation for Science & Technology (FCT) Grants PTDC/SAU-NMC/113934/2009 (to I.S.); the European Union FP7 Project SwitchBox (N.S. and O.F.X.A.); the Portuguese North Regional Operational Program (ON.2-O Novo Norte) under the National Strategic Reference Framework (QREN) through the European Regional Development Fund (FEDER); and the Education and Lifelong Learning, Supporting Postdoctoral Researchers and Large Scale Cooperative Project, cofinanced by the European Social Fund and the Greek General Secretariat for Research and Technology. J.V.-S. is a recipient of a PhD fellowship (PD/BD/105938/2014) of the University of Minho MD/PhD Program funded by the FCT

Corticosteroid status influences the volume of the rat cingulate cortex: a magnetic resonance imaging study

Imbalances in the corticosteroid milieu result in reductions in hippocampal volume in humans and experimental rodents. The functional correlates of these changes include deficits in cognitive performance and regulation of the hypothalamic–pituitary–adrenal axis. Since other limbic structures which are intricately connected with the hippocampal formation, also play an important role in behavioural and neuroendocrine functions, we here used magnetic resonance imaging (MRI) to analyse how two of these areas, the anterior cingulate and retrosplenial cortex, respond to chronic alterations of adrenocortical status: hypocortisolism (induced by adrenalectomy, ADX), normocortisolism (ADX with low-dose corticosterone replacement), and hypercortisolism (ADX with high-dose dexamethasone supplementation). Hypercortisolism was associated with a significant reduction in the volume (absolute and normalized) of the left anterior cingulate gyrus as measured by MRI and confirmed using classical histological methods; a similar trend was observed in the right anterior cingulate region. In contrast, hypercortisolism did not influence the volume of the adjacent retrosplenial cortex. The volumes of the anterior cingulate gyrus and retrosplenial cortex were unaffected by the absence of adrenocortical hormones. These findings are the first to suggest that corticosteroid influences on the structure of the limbic system extend beyond the hippocampal formation, i.e., to fronto-limbic areas also

Boron excess imbalances root/shoot allometry, photosynthetic and chlorophyll fluorescence parameters and sugar metabolism in apple plants

Boron (B) excess frequently impair plant performances and their productivity; in particular in arid and semi‐arid environments. In the present experiment; hydroponically‐grown ‘Granny Smith’ apple plants grafted on M9 rootstock were treated with optimal (25 μΜ) or excess (400 μΜ) B for 116 days to evaluate allometric responses of plants to B toxicity and to highlight physiological (photosynthesis and chlorophyll fluorescence) and biochemical (pigment content and sugar metabolism) responses of apple plants to B excess. Boron accumulated principally in top > middle > basal stems and leaves of high‐B‐stressed plants. Notably, the stem dramatically accumulated a higher level of B, as an attempt to preserve leaves, especially the youngest from further B accumulation. B accumulation seriously affected photosynthesis of younger leaves and caused both stomata (reduced stomatal conductance) and biochemical (reduction of apparent CO2 use efficiency and pigment content) limitations and altered the photochemistry and energy partitioning in photosystem II. Boron excess altered leaf sugar proportion; increasing the accumulation of non‐translocating sugars such as glucose and fructose. Our dataset adds knowledge on the effect of B excess in apple tree and poses serious concerns about the possible effect of B in altering sugar metabolism; which, in turn, can strongly affect fruit production of this worldwide‐cropped species