1,721,177 research outputs found
Contributo alla conoscenza dei terrazzi marini della Liguria fra Genova Nervi e Camogli
No full textThis paper focuses on the evidence of past sea levels recognized in a specific tract of the Eastern Liguria coast, located immediately eastward the city of Genoa. From a geological point of view, the study area presents a good uniformity since only Antola Unit, consisting of marls, limestone, calcarenite, sandstone and shale, outcrops here. The geomorphological survey of the coast between Nervi and Camogli, provides well-defined markers of at least two highstands, in the form of a staircase of marine terraces, within an altitude span ranging from present-day sea level to the 34 m contour line. Very often these terraces appear covered by continental sediments or altered from erosion processes, uplift and the strong human impact that affects the study area. Although no patches of the original marine deposit of these terraces have been found yet, they are currently undated and their age attribution is attempted in this paper by means of correlation with dated shorelines. Despite of the underlined difficulties, the altitude of the terraces inner margins were obtained on the base of field measurements and two orders of terraces were identified. The terraced landforms of the upper order (I), with inner margins ranging between 24 and 34 m, are developed with few interruptions along the studied stretch of coast and are also often overlain by continental deposits due to alluvial fan or landslide. The cluster value for the upper order is 27 +1/-6 that is the median value of the measured inner margins with the assumed error, related to the inaccuracy of the measurement instrument (±1 m) and the evaluation of the sediment thickness (+5 m). The second order of terraces are characterized by an elevation of the inner margin ranging between 3-5 m a.s.l. The marker of this order is represented by platform of marine abrasion cut in the rock, without sediments on the surface, often affected by weathering. The upper group of terraces could be attributed to the MIS 5.5 highstand for correlation with a dated shoreline 30 km eastward the study area; consequently the lower group are in this hypothesis attributed to MIS 5.3 or 5.1. Another hypothesis, based on the correlation with the Western Liguria data, attributes the lower order to the M.I.S. 5.5 and the upper order to a previous isotopic stage. Considering the available data, the authors don't draw any conclusion about the geodynamic behaviour of the study area. In fact a different uplift rate would derive from each of the two proposed hypotheses and consequently a different vertical displacement for the two tracts of coast
The problem of using marine terraces with unclear inner edge for palaeo sea-level determination: a case study from Liguria (NW Italy)
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
The nature of catecholamine-containing neurons in the enteric nervous system in relationship with organogenesis, normal human anatomy and neurodegeneration.
No full textThe gastrointestinal tract is provided with extrinsic and intrinsic innervation. The extrinsic innervation includes the classic vagal parasympathetic and sympathetic components, with afferent sensitive and efferent secretomotor fibers. The intrinsic innervations is represented by the enteric nervous system (ENS), which is recognized as a complex neural network controlling a variety of cell populations, including smooth muscle cells, mucosal secretory cells, endocrine cells, microvasculature, immune and inflammatory cells. This is finalized to regulate gastrointestinal secretion, absorption and motility. In particular, this network is organized in several plexuses each one providing quite autonomous control of gastrointestinal functions (hence the definition of "second brain"). The similarity between ENS and CNS is further substantiated by the presence of local sensitive pseudo- unipolar ganglionic neurons with both peripheral and central branching which terminate in the enteric wall. A large variety of neurons and neurotransmitters takes part in the ENS. However, the nature of these neurons and their role in the regulation of gastrointestinal functions is debatable. In particular, the available literature reporting the specific nature of catecholamine- containing neurons provides conflicting evidence. This is critical both for understanding the specific role of each catecholamine in the gut and, mostly, to characterize specifically the enteric neuropathology occurring in a variety of diseases. An emphasis is posed on neurodegenerative disorders, such as Parkinson's disease, which is associated with the loss of catecholamine neurons. In this respect, the recognition of the nature of such neurons within the ENS would contribute to elucidate the pathological mechanisms which produce both CNS and ENS degeneration and to achieve more effective therapeutic approaches. Despite a great emphasis is posed on the role of noradrenaline to regulate enteric activities only a few reports are available on the anatomy and physiology of enteric dopamine neurons. Remarkably, this review limits the presence of enteric noradrenaline (and adrenaline) only within extrinsic sympathetic nerve terminals. This is based on careful morphological studies showing that the only catecholamine-containing neurons within ENS would be dopaminergic. This means that enteric pathology of catecholamine neurons should be conceived as axon pathology for noradrenaline neurons and whole cell pathology for dopamine neurons which would be the sole catecholamine cell within intrinsic circuitries affecting gut motility and secretions.The gastrointestinal tract is provided with extrinsic and intrinsic innervation. The extrinsic innervation includes the classic vagal parasympathetic and sympathetic components, with afferent sensitive and efferent secretomotor fibers. The intrinsic innervations is represented by the enteric nervous system (ENS), which is recognized as a complex neural network controlling a variety of cell populations, including smooth muscle cells, mucosal secretory cells, endocrine cells, microvasculature, immune and inflammatory cells. This is finalized to regulate gastrointestinal secretion, absorption and motility. In particular, this network is organized in several plexuses each one providing quite autonomous control of gastrointestinal functions (hence the definition of "second brain"). The similarity between ENS and CNS is further substantiated by the presence of local sensitive pseudounipolar ganglionic neurons with both peripheral and central branching which terminate in the enteric wall. A large variety of neurons and neurotransmitters takes part in the ENS. However, the nature of these neurons and their role in the regulation of gastrointestinal functions is debatable. In particular, the available literature reporting the specific nature of catecholamine-containing neurons provides conflicting evidence. This is critical both for understanding the specific role of each catecholamine in the gut and, mostly, to characterize specifically the enteric neuropathology occurring in a variety of diseases. An emphasis is posed on neurodegenerative disorders, such as including Parkinson's disease, which is associated with the loss of catecholamine neurons. In this respect, the recognition of the nature of such neurons within the ENS would contribute to elucidate the pathological mechanisms which produce both CNS and ENS degeneration and to achieve more effective therapeutic approaches. Despite a great emphasis is posed on the role of noradrenaline to regulate enteric activities only a few reports are available on the anatomy and physiology of enteric dopamine neurons. Remarkably, this review limits the presence of enteric noradrenaline (and adrenaline) only within extrinsic sympathetic nerve terminals. This is based on careful morphological studies showing that the only catecholamine-containing neurons within ENS would be dopaminergic. This means that enteric pathology of catecholamine neurons should be conceived as axon pathology for noradrenaline neurons and whole cell pathology for dopamine neurons which would be the sole catecholamine cell within intrinsic circuitries affecting gut motility and secretions
Cell To Cell Spreading Of Misfolded Proteins As A Therapeutic Target In Motor Neuron Disease.
No full textDespite a number of genetic mutations and molecular mechanisms are recognized to participate in amyotrophic lateral sclerosis (ALS), such a devastating neurological disorder still lacks a substantial cure. The present manuscript rather than a general overview of potential therapeutic approaches focuses on novel research findings detailing novel molecular mechanisms which appear to be promising for developing future ALS therapeutics. A special emphasis is given to the abnormal autophagy status and to those autophagy substrates which aggregate in the form of misfolded proteins. In fact, as reviewed in the first part of the manuscript, altered autophagy pathway is present in most genetic mutations responsible for familial ALS. These mutations impair clearance of autophagy substrates, which determines accumulation of giant altered mitochondria and misfolded proteins. Therefore, a considerable piece of the review is dedicated to unconventional processing of misfolded proteins leading to unconventional protein secretions which may underlie a prionoid cellto- cell spreading of ALS neuropathology. The intimate mechanisms regulating these steps are analyzed in order to comprehend which potential therapeutic targets might be considered in future studies. At the same time, negative findings concerning recent trials are explained in light of novel disease mechanisms. In the final part of the review the replacement therapy with focal stem cells implantation is discussed in relationship with toxic mechanisms operating in the intercellular space of the spinal cord and motor-related areas
MTOR modulates intercellular signals for enlargement and infiltration in glioblastoma multiforme
Full text linkRecently, exosomal release has been related to the acquisition of a malignant phenotype in glioblastoma cancer stem cells (GSCs). Remarkably, intriguing reports demonstrate that GSC-derived extracellular vesicles (EVs) contribute to glioblastoma multiforme (GBM) tumorigenesis via multiple pathways by regulating tumor growth, infiltration, and immune invasion. In fact, GSCs release tumor-promoting macrovesicles that can disseminate as paracrine factors to induce phenotypic alterations in glioma-associated parenchymal cells. In this way, GBM can actively recruit different stromal cells, which, in turn, may participate in tumor microenvironment (TME) remodeling and, thus, alter tumor progression. Vice versa, parenchymal cells can transfer their protein and genetic contents to GSCs by EVs; thus, promoting GSCs tumorigenicity. Moreover, GBM was shown to hijack EV-mediated cell-to-cell communication for self-maintenance. The present review examines the role of the mammalian Target of Rapamycin (mTOR) pathway in altering EVs/exosome-based cell-to-cell communication, thus modulating GBM infiltration and volume growth. In fact, exosomes have been implicated in GSC niche maintenance trough the modulation of GSCs stem cell-like properties, thus, affecting GBM infiltration and relapse. The present manuscript will focus on how EVs, and mostly exosomes, may act on GSCs and neighbor non tumorigenic stromal cells to modify their expression and translational profile, while making the TME surrounding the GSC niche more favorable for GBM growth and infiltration. Novel insights into the mTOR-dependent mechanisms regulating EV-mediated intercellular communication within GBM TME hold promising directions for future therapeutic applications
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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