578 research outputs found

    Properties and characterization of biodiesel from selected microalgea stains

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    The demand for alternative fuels has increased in the past several years[1]. Biofuels are gaining importance as significant substitutes for the depleting fossil fuels. The fact that biofuels are renewable fuels with very low emissions of CO2 in the lifecycle offers them a competitive advantage[2]. However, the first produced biodiesel derived from edible oil seed crops (first generation feedstocks), lurking a serious risk of disturbing the overall worldwide balance of food reserves and safety. The second generation feedstocks for biodiesel production obtained from non-edible oil seed crops, waste cooking oil, animal fats, etc., but these feedstocks are not sufficient to cover the present energy needs. Recent focus is on microalgae as the third generation feedstock[3]. Mi l d t t f l d b t th i lt ( ) b kih(l ) df h Microalgae do not compete for land, but they can grow in salty sea), brackish (lagoons) and fresh (lakes) water. Moreover, microalgae have high photosynthetic efficiency using solar energy, water and carbon dioxide to produce higher quantities of biomass than other feedstocks. In the present research work, two indigenous fresh water (ChlorF1, ChlorF2) and two marine (ChlorM1, ChlorM2) Chlorophyte strains have been cultivated successfully under laboratory conditions using commercial fertilizer (Nutrileaf 30-10-10, initial concentration=70 g/m3) as nutrient source. The produced biodiesel from the microalgae biomass achieved a range of 2.2 - 10.6% total lipid content and an unsaturated FAME content between 48 mol% and 59 mol%. The iodine value, the cetane number, the cold filter plugging point (CFPP) and the oxidative stability of the ultimate biodiesels were determined, based on the compositions of the four (4) microalgae strains and compared with the specifications in the EU and US standards, EN 14214 and ASTM D6751 respectively

    The unresolved case of sacral chordoma: from misdiagnosis to challenging surgery and medical therapy resistance.

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    PURPOSE: A sacral chordoma is a rare, slow-growing, primary bone tumor, arising from embryonic notochordal remnants. Radical surgery is the only hope for cure. The aim of our present study is to analyse our experience with the challenging treatment of this rare tumor, to review current treatment modalities and to assess the outcome based on R status. METHODS: Eight patients were treated in our institution between 2001 and 2011. All patients were discussed by a multidisciplinary tumor board, and an en bloc surgical resection by posterior perineal access only or by combined anterior/posterior accesses was planned based on tumor extension. RESULTS: Seven patients underwent radical surgery, and one was treated by using local cryotherapy alone due to low performance status. Three misdiagnosed patients had primary surgery at another hospital with R1 margins. Reresection margins in our institution were R1 in two and R0 in one, and all three recurred. Four patients were primarily operated on at our institution and had en bloc surgery with R0 resection margins. One had local recurrence after 18 months. The overall morbidity rate was 86% (6/7 patients) and was mostly related to the perineal wound. Overall, 3 out of 7 resected patients were disease-free at a median follow-up of 2.9 years (range, 1.6-8.0 years). CONCLUSION: Our experience confirms the importance of early correct diagnosis and of an R0 resection for a sacral chordoma invading pelvic structures. It is a rare disease that requires a challenging multidisciplinary treatment, which should ideally be performed in a tertiary referral center

    Impaired wound healing secondary to bevacizumab

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    Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150555/1/iwj13139_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150555/2/iwj13139.pd

    Chemokine Transfer by Liver Sinusoidal Endothelial Cells Contributes to the Recruitment of CD4+ T Cells into the Murine Liver

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    Leukocyte adhesion and transmigration are central features governing immune surveillance and inflammatory reactions in body tissues. Within the liver sinusoids, chemokines initiate the first crucial step of T-cell migration into the hepatic tissue. We studied molecular mechanisms involved in endothelial chemokine supply during hepatic immune surveillance and liver inflammation and their impact on the recruitment of CD4+ T cells into the liver. In the murine model of Concanavalin A-induced T cell-mediated hepatitis, we showed that hepatic expression of the inflammatory CXC chemokine ligands (CXCL)9 and CXCL10 strongly increased whereas homeostatic CXCL12 significantly decreased. Consistently, CD4+ T cells expressing the CXC chemokine receptor (CXCR)3 accumulated within the inflamed liver tissue. In histology, CXCL9 was associated with liver sinusoidal endothelial cells (LSEC) which represent the first contact site for T-cell immigration into the liver. LSEC actively transferred basolaterally internalized CXCL12, CXCL9 and CXCL10 via clathrin- coated vesicles to CD4+ T cells leading to enhanced transmigration of CXCR4+ total CD4+ T cells and CXCR3+ effector/memory CD4+ T cells, respectively in vitro. LSEC-expressed CXCR4 mediated CXCL12 transport and blockage of endothelial CXCR4 inhibited CXCL12-dependent CD4+ T-cell transmigration. In contrast, CXCR3 was not involved in the endothelial transport of its ligands CXCL9 and CXCL10. The clathrin-specific inhibitor chlorpromazine blocked endothelial chemokine internalization and CD4+ T-cell transmigration in vitro as well as migration of CD4+ T cells into the inflamed liver in vivo. Moreover, hepatic accumulation of CXCR3+ CD4+ T cells during T cell-mediated hepatitis was strongly reduced after administration of chlorpromazine. These data demonstrate that LSEC actively provide perivascularly expressed homeostatic and inflammatory chemokines by CXCR4- and clathrin-dependent intracellular transport mechanisms thereby contributing to the hepatic recruitment of CD4+ T-cell populations during immune surveillance and liver inflammation

    Phosphatidylinositol(4,5)bisphosphate coordinates actin-mediated mobilization and translocation of secretory vesicles to the plasma membrane of chromaffin cells

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    ORP5 and ORP8, members of the oxysterol-binding protein (OSBP)-related proteins (ORP) family, are endoplasmic reticulum membrane proteins implicated in lipid trafficking. ORP5 and ORP8 are reported to localize to endoplasmic reticulum-plasma membrane junctions via binding to phosphatidylinositol-4-phosphate (PtdIns(4)P), and act as a PtdIns(4)P/phosphatidylserine counter exchanger between the endoplasmic reticulum and plasma membrane. Here we provide evidence that the pleckstrin homology domain of ORP5/8 via PtdIns(4,5)P 2, and not PtdIns(4)P binding mediates the recruitment of ORP5/8 to endoplasmic reticulum-plasma membrane contact sites. The OSBP-related domain of ORP8 can extract and transport multiple phosphoinositides in vitro, and knocking down both ORP5 and ORP8 in cells increases the plasma membrane level of PtdIns(4,5)P 2 with little effect on PtdIns(4)P. Overall, our data show, for the first time, that phosphoinositides other than PtdIns(4)P can also serve as co-exchangers for the transport of cargo lipids by ORPs.ORP5/8 are endoplasmic reticulum (ER) membrane proteins implicated in lipid trafficking that localize to ER-plasma membrane (PM) contacts and maintain membrane homeostasis. Here the authors show that PtdIns(4,5)P 2 plays a critical role in the targeting and function of ORP5/8 at the PM

    A DYNAMIC CONTENT MANAGEMENT SYSTEM FOR THE VISUALIZATION OF CULTURAL INFORMATION; THE CASE OF THE STATE CONSERVATORY OF THESSALONIKI, GR

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    Although there are several attempts of embedding static content in events’ brochures and posters, the increasing need for flexibility and versatility of the content, leads to the development of a mobile application with an in-app dynamic content management system. In this context, DigiOrch is an ongoing research program where, a Content Management System is developed to organize all the digital material and maintain the appropriate connection to the analogical markers. Furthermore, a mobile application is developed that lev-erages this system using in app dynamic modules, which, by utilizing the augmented reality technology, presents multimedia data such as texts, photos, videos, and 3D Models to the end-user by “superimposing” them on mobile devices screen, providing extra additional information on any valid smart-leaflet.The overall workflow of the in-app Dynamic Content Management System (DCMS) can be described as a group of modules that managing and copying content files from a remote infrastructure such as an ftp server or a local resource if network is missing, to the mobile device’s file system.The in-app DCMS consists of 4 modules: The first module is the parser, which is responsible for reading a downloaded *.json file and creating content-linked objects. The second module is the download module which is responsible for downloading the overall content by iterating the content-linked objects, created by the previous module. The third module le is the update module that, by iterating the initial content file and the local file system, suggests whether a content update is necessary. The fourth module is the loading module, which is responsible for fetching the content on runtime to fill the content-holding components, such as 3D Models and UI photo galleries, of the AR scenes on runtime.</p

    The Rab5 effector Rabankyrin-5 regulates and coordinates different endocytic mechanisms

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    The small GTPase Rab5 is a key regulator of clathrin-mediated endocytosis. On early endosomes, within a spatially restricted domain enriched in phosphatydilinositol-3-phosphate [PI(3)P], Rab5 coordinates a complex network of effectors that functionally cooperate in membrane tethering, fusion, and organelle motility. Here we discovered a novel PI(3)P-binding Rab5 effector, Rabankyrin-5, which localises to early endosomes and stimulates their fusion activity. In addition to early endosomes, however, Rabankyrin-5 localises to large vacuolar structures that correspond to macropinosomes in epithelial cells and fibroblasts. Overexpression of Rabankyrin-5 increases the number of macropinosomes and stimulates fluid-phase uptake, whereas its downregulation inhibits these processes. In polarised epithelial cells, this function is primarily restricted to the apical membrane. Rabankyrin-5 localises to large pinocytic structures underneath the apical surface of kidney proximal tubule cells, and its overexpression in polarised Madin-Darby canine kidney cells stimulates apical but not basolateral, non-clathrin-mediated pinocytosis. In demonstrating a regulatory role in endosome fusion and (macro)pinocytosis, our studies suggest that Rab5 regulates and coordinates different endocytic mechanisms through its effector Rabankyrin-5. Furthermore, its active role in apical pinocytosis in epithelial cells suggests an important function of Rabankyrin-5 in the physiology of polarised cells.PLoS Bio

    Rabenosyn-5, a novel Rab5 effector, is complexed with hVPS45 and recruited to endosomes through a FYVE finger domain

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    Rab5 regulates endocytic membrane traffic by specifically recruiting cytosolic effector proteins to their site of action on early endosomal membranes. We have characterized a new Rab5 effector complex involved in endosomal fusion events. This complex includes a novel protein, Rabenosyn-5, which, like the previously characterized Rab5 effector early endosome antigen 1 (EEA1), contains an FYVE finger domain and is recruited in a phosphatidylinositol-3-kinase-dependent fashion to early endosomes. Rabenosyn-5 is complexed to the Sec1-like protein hVPS45. hVPS45 does not interact directly with Rab5, therefore Rabenosyn-5 serves as a molecular link between hVPS45 and the Rab5 GTPase. This property suggests that Rabenosyn-5 is a closer mammalian functional homologue of yeast Vac1p than EEA1. Furthermore, although both EEA1 and Rabenosyn-5 are required for early endosomal fusion, only overexpression of Rabenosyn-5 inhibits cathepsin D processing, suggesting that the two proteins play distinct roles in endosomal trafficking. We propose that Rab5-dependent formation of membrane domains enriched in phosphatidylinositol-3-phosphate has evolved as a mechanism for the recruitment of multiple effector proteins to mammalian early endosomes, and that these domains are multifunctional, depending on the differing activities of the effector proteins recruited.J Cell Bio

    VEGF induces signalling and angiogenesis by directing VEGFR2 internalisation via macropinocytosis

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    Endocytosis plays critical role in receptor signalling. VEGFR2 and its ligand VEGFA are fundamental in neovascularization. Yet, our understanding of the role of endocytosis in VEGFR2 signalling remains limited. Despite the existence of diverse internalisation routes, the only known endocytic pathway of VEGFR2 is the clathrin-mediated. Here, we show that this pathway is the predominant internalisation route of VEGFR2 only in the absence of ligand. Intriguingly, VEGF introduces a novel internalisation itinerary for VEGFR2, the pathway of macropinocytosis, which becomes the prevalent endocytic route of the receptor in the presence of ligand, while the route of clathrin becomes minor. Macropinocytic internalisation of VEGFR2, which mechanistically is mediated via the small GTPase CDC42, takes place via macropinosomes generated at ruffling areas of the membrane. Interestingly, macropinocytosis plays critical role in VEGF-induced signalling, endothelial cell functions in vitro and angiogenesis in vivo, while clathrin-mediated endocytosis is not essential for VEGF signalling. These findings expand our knowledge on the endocytic pathways of VEGFR2 and suggest that VEGF-driven internalisation of VEGFR2 via macropinocytosis is essential for endothelial cell signalling and angiogenesis
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