Sample records for scar-like perivascular barriers

  1. Spinal cord compression injury in guinea pigs: structural changes of endothelium and its perivascular cell associations after blood-brain barrier breakdown and repair. (United States)

    Jaeger, C B; Blight, A R


    This study examines morphological changes of the blood-brain barrier (BBB) after spinal cord compression. The lowest thoracic segment (T13) of female guinea pigs was injured and the BBB was tested from 7 days to 5.5 months postinjury using intravenously injected horseradish peroxidase (HRP) as a tracer. Tracer leakage in the injured segment was verified with the light microscope and the fine structure of capillaries was examined. Diffuse tissue staining was observed at T13 up to 2 weeks following injury. A leaky BBB correlated with expected changes in the fine structure of endothelial cell junctions. These were predominantly nonoverlapping cell junctions which, in many instances, were separated by clefts between adjacent cells. At early survival times, numerous capillary profiles with juxtaposed astrocyte foot processes were noted in addition to altered cell associations. Complete sealing of the BBB against interstitial HRP leakage was not observed until 17 days postinjury. After the first week, some of the endothelial cells were contacted by macrophages, processes of perivascular microglia, and processes of swollen and degenerating astrocytes. Perivascular spaces varied in extent and contained amorphous deposits of extracellular materials in addition to supernumerary layers of basal lamina. The early changes were followed by profound tissue restructuring due to loss of both neurons and glia. At longer survival times the BBB to HRP repaired. Endothelial cells formed complex overlapping junctions with zonulae occludentes. Most of the capillaries in the injured segment were no longer in direct contact with astrocyte foot processes, although reactive astrocytes constituted the predominant cell type in the remaining gray matter. Substantial expansion of perivascular spaces was evident. The cytoplasm of endothelial cells had numerous pinocytotic vesicles. Perivascular spaces contained layers of assembled collagen arranged perpendicularly to each other in addition to

  2. Olfactory ensheathing cell-neurite alignment enhances neurite outgrowth in scar-like cultures (United States)

    Khankan, Rana R.; Wanner, Ina B.; Phelps, Patricia E.


    The regenerative capacity of the adult CNS neurons after injury is strongly inhibited by the spinal cord lesion site environment that is composed primarily of the reactive astroglial scar and invading meningeal fibroblasts. Olfactory ensheathing cell (OEC) transplantation facilitates neuronal survival and functional recovery after a complete spinal cord transection, yet the mechanisms by which this recovery occurs remain unclear. We used a unique multicellular scar-like culture model to test if OECs promote neurite outgrowth in growth inhibitory areas. Astrocytes were mechanically injured and challenged by meningeal fibroblasts to produce key inhibitory elements of a spinal cord lesion. Neurite outgrowth of postnatal cerebral cortical neurons was assessed on three substrates: quiescent astrocyte control cultures, reactive astrocyte scar-like cultures, and scar-like cultures with OECs. Initial results showed that OECs enhanced total neurite outgrowth of cortical neurons in a scar-like environment by 60%. We then asked if the neurite growth-promoting properties of OECs depended on direct alignment between neuronal and OEC processes. Neurites that aligned with OECs were nearly three times longer when they grew on inhibitory meningeal fibroblast areas and twice as long on reactive astrocyte zones compared to neurites not associated with OECs. Our results show that OECs can independently enhance neurite elongation and that direct OEC-neurite cell contact can provide a permissive substrate that overcomes the inhibitory nature of the reactive astrocyte scar border and the fibroblast-rich spinal cord lesion core. PMID:25863021

  3. Evidence from dithizone and selenium zinc histochemistry that perivascular mossy fiber boutons stain preferentially "in vivo". (United States)

    Howell, G A; Frederickson, C J; Danscher, G


    This paper describes a perivascular staining pattern that is obtained when dithizone or sodium selenite are used to label zinc intravitally. Our observations indicate that the perivascular staining is a result of zinc labeling in mossy fiber boutons adjacent to capillaries and suggest that there might be a special blood brain barrier in the mossy fiber regions.

  4. A novel perivascular cell population in the zebrafish brain (United States)

    Galanternik, Marina Venero; Castranova, Daniel; Gore, Aniket V; Blewett, Nathan H; Jung, Hyun Min; Stratman, Amber N; Kirby, Martha R; Iben, James; Miller, Mayumi F; Kawakami, Koichi; Maraia, Richard J; Weinstein, Brant M


    The blood-brain barrier is essential for the proper homeostasis and function of the CNS, but its mechanism of function is poorly understood. Perivascular cells surrounding brain blood vessels are thought to be important for blood-brain barrier establishment, but their roles are not well defined. Here, we describe a novel perivascular cell population closely associated with blood vessels on the zebrafish brain. Based on similarities in their morphology, location, and scavenger behavior, these cells appear to be the zebrafish equivalent of cells variably characterized as Fluorescent Granular Perithelial cells (FGPs), perivascular macrophages, or ‘Mato Cells’ in mammals. Despite their macrophage-like morphology and perivascular location, zebrafish FGPs appear molecularly most similar to lymphatic endothelium, and our imaging studies suggest that these cells emerge by differentiation from endothelium of the optic choroidal vascular plexus. Our findings provide the first report of a perivascular cell population in the brain derived from vascular endothelium. DOI: PMID:28395729

  5. Perivascular cells for regenerative medicine. (United States)

    Crisan, Mihaela; Corselli, Mirko; Chen, William C W; Péault, Bruno


    Mesenchymal stem/stromal cells (MSC) are currently the best candidate therapeutic cells for regenerative medicine related to osteoarticular, muscular, vascular and inflammatory diseases, although these cells remain heterogeneous and necessitate a better biological characterization. We and others recently described that MSC originate from two types of perivascular cells, namely pericytes and adventitial cells and contain the in situ counterpart of MSC in developing and adult human organs, which can be prospectively purified using well defined cell surface markers. Pericytes encircle endothelial cells of capillaries and microvessels and express the adhesion molecule CD146 and the PDGFRβ, but lack endothelial and haematopoietic markers such as CD34, CD31, vWF (von Willebrand factor), the ligand for Ulex europaeus 1 (UEA1) and CD45 respectively. The proteoglycan NG2 is a pericyte marker exclusively associated with the arterial system. Besides its expression in smooth muscle cells, smooth muscle actin (αSMA) is also detected in subsets of pericytes. Adventitial cells surround the largest vessels and, opposite to pericytes, are not closely associated to endothelial cells. Adventitial cells express CD34 and lack αSMA and all endothelial and haematopoietic cell markers, as for pericytes. Altogether, pericytes and adventitial perivascular cells express in situ and in culture markers of MSC and display capacities to differentiate towards osteogenic, adipogenic and chondrogenic cell lineages. Importantly, adventitial cells can differentiate into pericyte-like cells under inductive conditions in vitro. Altogether, using purified perivascular cells instead of MSC may bring higher benefits to regenerative medicine, including the possibility, for the first time, to use these cells uncultured. © 2012 The Authors Journal of Cellular and Molecular Medicine © 2012 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

  6. Significance of MRI Perivascular Spaces in MS

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    J Gordon Millichap


    Full Text Available The role of perivascular Virchow-Robin spaces was investigated in 45 multiple sclerosis (MS patients and 30 healthy controls, in a study at Charite-Universitaetsmedizin Berlin, and Goethe University, Frankfurt.

  7. Perivascular Epithelioid Cell Tumor in the Stomach

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    Sun Ah Shin


    Full Text Available Perivascular epithelioid cell tumors or PEComas can arise in any location in the body. However, a limited number of cases of gastric PEComa have been reported. We present two cases of gastric PEComas. The first case involved a 62-year-old woman who presented with a 4.2 cm gastric subepithelial mass in the prepyloric antrum, and the second case involved a 67-year-old man with a 5.0 cm mass slightly below the gastroesophageal junction. Microscopic examination revealed that both tumors were composed of perivascular epithelioid cells that were immunoreactive for melanocytic and smooth muscle markers. Prior to surgery, the clinical impression of both tumors was gastrointestinal stromal tumor (GIST, and the second case was erroneously diagnosed as GIST even after microscopic examination. Although gastric PEComa is a very rare neoplasm, it should be considered in the differential diagnosis of gastric submucosal lesions.

  8. Perivascular Adipose Tissue and Cardiometabolic Disease


    Anna Meiliana; Andi Wijaya


    BACKGROUND: Obesity is associated with insulin resistance, hypertension, and cardiovascular disease, but the mechanisms underlying these associations are incompletely understood. Microvascular dysfunction may play an important role in the pathogenesis of both insulin resistance and hypertension in obesity. CONTENT: Perivascular adipose tissue (PVAT) is a local deposit of adipose tissue surrounding the vasculature. PVAT is present throughout the body and has been shown to have a local effect o...

  9. Perivascular Adipose Tissue and Cardiometabolic Disease

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    Anna Meiliana


    Full Text Available BACKGROUND: Obesity is associated with insulin resistance, hypertension, and cardiovascular disease, but the mechanisms underlying these associations are incompletely understood. Microvascular dysfunction may play an important role in the pathogenesis of both insulin resistance and hypertension in obesity. CONTENT: Perivascular adipose tissue (PVAT is a local deposit of adipose tissue surrounding the vasculature. PVAT is present throughout the body and has been shown to have a local effect on blood vessels. The influence of PVAT on the vasculature changes with increasing adiposity. PVAT similarly to other fat depots, is metabolically active, secreting a wide array of bioactive substances, termed ‘adipokines’. Adipokines include cytokines, chemokines and hormones that can act in a paracrine, autocrine or endocrine fashion. Many of the proinflammatory adipokines upregulated in obesity are known to influence vascular function, including endothelial function, oxidative stress, vascular stiffness and smooth muscle migration. Adipokines also stimulate immune cell migration into the vascular wall, potentially contributing to the inflammation found in atherosclerosis. Finally, adipokines modulate the effect of insulin on the vasculature, thereby decreasing insulin-mediated muscle glucose uptake. This leads to alterations in nitric oxide signaling, insulin resistance and potentially atherogenesis. SUMMARY: PVAT surrounds blood vessels. PVAT and the adventitial layer of blood vessels are in direct contact with each other. Healthy PVAT secretes adipokines and regulates vascular function. Obesity is associated with changes in adipokine secretion and the resultant inflammation of PVAT. The dysregulation of adipokines changes the effect of PVAT on the vasculature. Changes in perivascular adipokines secretion in obesity appear to contribute to the development of obesity-mediated vascular disease. KEYWORDS: obesity, perivascular adipose tissue, PVAT

  10. Nerve growth factor facilitates perivascular innervation in neovasculatures of mice

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    Mitsuhiro Goda


    Full Text Available It is well known that blood vessels including arterioles have a perivascular innervation. It is also widely accepted that perivascular nerves maintain vascular tone and regulate blood flow. Although there are currently prevailing opinions, unified views on the innervation of microcirculation in any organs have not been established. The present study was designed to investigate whether there are perivascular nerves innervated in microvessels and neovessels. Furthermore, we examined whether nerve growth factor (NGF can exert a promotional effect on perivascular nerve innervation in neovessels of Matrigel plugs. A Matrigel was subcutaneously implanted in mouse. The presence of perivascular nerves in Matrigel on Day 7–21 after the implantation was immunohistochemically studied. NGF or saline was subcutaneously administered by an osmotic mini-pump for a period of 3–14 days. The immunostaining of neovasculatures in Matrigel showed the presence of perivascular nerves on Day 21 after Matrigel injection. Perivascular nerve innervation of neovessels within Matrigel implanted in NGF-treated mice was observed in Day 17 after Matrigel implantation. However, NGF treatment did not increase numbers of neovessels in Matrigel. These results suggest that perivascular nerves innervate neovessels as neovasculatures mature and that NGF accelerates the innervation of perivascular nerves in neovessels.

  11. How do culture media influence in vitro perivascular cell behavior? (United States)

    Huber, Birgit; Volz, Ann-Cathrin; Kluger, Petra Juliane


    Perivascular cells are multilineage cells located around the vessel wall and important for wall stabilization. In this study, we evaluated a stem cell media and a perivascular cell-specific media for the culture of primary perivascular cells regarding their cell morphology, doubling time, stem cell properties, and expression of cell type-specific markers. When the two cell culture media were compared to each other, perivascular cells cultured in the stem cell medium had a more elongated morphology and a faster doubling rate and cells cultured in the pericyte medium had a more typical morphology, with several filopodia, and a slower doubling rate. To evaluate stem cell properties, perivascular cells, CD146(-) cells, and mesenchymal stem cells (MSCs) were differentiated into the adipogenic, osteogenic, and chondrogenic lineages. It was seen that perivascular cells, as well as CD146(-) cells and MSCs, cultured in stem cell medium showed greater differentiation than cells cultured in pericyte-specific medium. The expression of pericyte-specific markers CD146, neural/glial antigen 2 (NG2), platelet-derived growth factor receptor-β (PDGFR-β), myosin, and α-smooth muscle actin (α-SMA) could be found in both pericyte cultures, as well as to varying amounts in CD146(-) cells, MSCs, and endothelial cells. The here presented work shows that perivascular cells can adapt to their in vitro environment and cell culture conditions influence cell functionality, such as doubling rate or differentiation behavior. Pericyte-specific markers were shown to be expressed also from cells other than perivascular cells. We can further conclude that CD146(+) perivascular cells are inhomogeneous cell population probably containing stem cell subpopulations, which are located perivascular around capillaries. © 2015 International Federation for Cell Biology.

  12. Fluid mechanics in the perivascular space. (United States)

    Wang, Peng; Olbricht, William L


    Perivascular space (PVS) within the brain is an important pathway for interstitial fluid (ISF) and solute transport. Fluid flowing in the PVS can affect these transport processes and has significant impacts on physiology. In this paper, we carry out a theoretical analysis to investigate the fluid mechanics in the PVS. With certain assumptions and approximations, we are able to find an analytical solution to the problem. We discuss the physical meanings of the solution and particularly examine the consequences of the induced fluid flow in the context of convection-enhanced delivery (CED). We conclude that peristaltic motions of the blood vessel walls can facilitate fluid and solute transport in the PVS. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Cellular kinetics of perivascular MSC precursors. (United States)

    Chen, William C W; Park, Tea Soon; Murray, Iain R; Zimmerlin, Ludovic; Lazzari, Lorenza; Huard, Johnny; Péault, Bruno


    Mesenchymal stem/stromal cells (MSCs) and MSC-like multipotent stem/progenitor cells have been widely investigated for regenerative medicine and deemed promising in clinical applications. In order to further improve MSC-based stem cell therapeutics, it is important to understand the cellular kinetics and functional roles of MSCs in the dynamic regenerative processes. However, due to the heterogeneous nature of typical MSC cultures, their native identity and anatomical localization in the body have remained unclear, making it difficult to decipher the existence of distinct cell subsets within the MSC entity. Recent studies have shown that several blood-vessel-derived precursor cell populations, purified by flow cytometry from multiple human organs, give rise to bona fide MSCs, suggesting that the vasculature serves as a systemic reservoir of MSC-like stem/progenitor cells. Using individually purified MSC-like precursor cell subsets, we and other researchers have been able to investigate the differential phenotypes and regenerative capacities of these contributing cellular constituents in the MSC pool. In this review, we will discuss the identification and characterization of perivascular MSC precursors, including pericytes and adventitial cells, and focus on their cellular kinetics: cell adhesion, migration, engraftment, homing, and intercellular cross-talk during tissue repair and regeneration.

  14. Cellular Kinetics of Perivascular MSC Precursors

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    William C. W. Chen


    Full Text Available Mesenchymal stem/stromal cells (MSCs and MSC-like multipotent stem/progenitor cells have been widely investigated for regenerative medicine and deemed promising in clinical applications. In order to further improve MSC-based stem cell therapeutics, it is important to understand the cellular kinetics and functional roles of MSCs in the dynamic regenerative processes. However, due to the heterogeneous nature of typical MSC cultures, their native identity and anatomical localization in the body have remained unclear, making it difficult to decipher the existence of distinct cell subsets within the MSC entity. Recent studies have shown that several blood-vessel-derived precursor cell populations, purified by flow cytometry from multiple human organs, give rise to bona fide MSCs, suggesting that the vasculature serves as a systemic reservoir of MSC-like stem/progenitor cells. Using individually purified MSC-like precursor cell subsets, we and other researchers have been able to investigate the differential phenotypes and regenerative capacities of these contributing cellular constituents in the MSC pool. In this review, we will discuss the identification and characterization of perivascular MSC precursors, including pericytes and adventitial cells, and focus on their cellular kinetics: cell adhesion, migration, engraftment, homing, and intercellular cross-talk during tissue repair and regeneration.

  15. Perivascular spaces and the two steps to neuroinflammation

    DEFF Research Database (Denmark)

    Owens, Trevor; Bechmann, Ingo; Engelhardt, Britta


    of capillaries, whereas the latter takes place in postcapillary venules. We summarize evidence that entry of immune cells into the CNS parenchyma in inflammatory conditions involves 2 differently regulated steps: transmigration of the vascular wall into the perivascular space and progression across the glia...

  16. Multilineage stem cells in the adult: a perivascular legacy? (United States)

    Crisan, Mihaela; Corselli, Mirko; Chen, Chien-Wen; Péault, Bruno


    Mesenchymal stem cells proliferate extensively in cultures of unselected, total cell isolates from multiple fetal and adult organs. Perivascular cells, principally pericytes surrounding capillaries and microvessels, but also adventitial cells located around larger arteries and veins, have been recently identified as possible originators of mesenchymal stem cells, first by phenotypic analogies and eventually following stringent cell sorting. While it is clear that purified perivascular cells exhibit multiple mesodermal developmental potentials and become indistinguishable from conventionally derived mesenchymal stem cells after in vitro culture, the possible roles played by these blood vessel-bound cells in organogenesis and adult tissue repair remain elusive. Unsolved questions regarding the identity of mesenchymal stem cells have not compromised the consideration of these cells as outstanding candidates for cell therapies. Better knowledge of the lineage affiliation, tissue distribution and molecular identity of mesenchymal stem cells will contribute to the development of more efficient, safer therapeutic cells.

  17. Perivascular adipose tissue: more than just structural support


    Szasz, Theodora; R Clinton Webb


    The perivascular adipose tissue (PVAT) has recently been recognized as a novel factor in vascular biology, with implications in the pathophysiology of cardiovascular disease. Composed mainly of adipocytes, PVAT releases a wide range of biologically active molecules that modulate the vascular smooth muscle cell contraction, proliferation and migration. PVAT exerts an anticontractile effect in various vascular beds which seems to be mediated by yet elusive PVAT-derived relaxing factor or factor...

  18. Lipopolysaccharide induced inflammation in the perivascular space in lungs

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    Pabst Reinhard


    Full Text Available Abstract Background Lipopolysaccharide (LPS contained in tobacco smoke and a variety of environmental and occupational dusts is a toxic agent causing lung inflammation characterized by migration of neutrophils and monocytes into alveoli. Although migration of inflammatory cells into alveoli of LPS-treated rats is well characterized, the dynamics of their accumulation in the perivascular space (PVS leading to a perivascular inflammation (PVI of pulmonary arteries is not well described. Methods Therefore, we investigated migration of neutrophils and monocytes into PVS in lungs of male Sprague-Dawley rats treated intratracheally with E. coli LPS and euthanized after 1, 6, 12, 24 and 36 hours. Control rats were treated with endotoxin-free saline. H&E stained slides were made and immunohistochemistry was performed using a monocyte marker and the chemokine Monocyte-Chemoattractant-Protein-1 (MCP-1. Computer-assisted microscopy was performed to count infiltrating cells. Results Surprisingly, the periarterial infiltration was not a constant finding in each animal although LPS-induced alveolitis was present. A clear tendency was observed that neutrophils were appearing in the PVS first within 6 hours after LPS application and were decreasing at later time points. In contrast, mononuclear cell infiltration was observed after 24 hours. In addition, MCP-1 expression was present in perivascular capillaries, arteries and the epithelium. Conclusion PVI might be a certain lung reaction pattern in the defense to infectious attacks.

  19. Depletion of B lymphocytes from cerebral perivascular spaces by rituximab. (United States)

    Martin, Maria del Pilar; Cravens, Petra D; Winger, Ryan; Kieseier, Bernd C; Cepok, Sabine; Eagar, Todd N; Zamvil, Scott S; Weber, Martin S; Frohman, Elliot M; Kleinschmidt-Demasters, Betty K; Montine, Thomas J; Hemmer, Bernhard; Marra, Christina M; Stüve, Olaf


    Rituximab is a recombinant chimeric monoclonal antibody against CD20, a molecule expressed on cells of the B-cell lineage. A phase 2 clinical trial recently provided strong evidence of the beneficial effects of rituximab in patients with relapsing-remitting multiple sclerosis. We and other investigators previously demonstrated that rituximab therapy depletes B lymphocytes from peripheral blood and cerebrospinal fluid of patients with relapsing-remitting multiple sclerosis. To determine the effect of rituximab on the presence of B cells in cerebral perivascular spaces. Design, Setting, and Patients Case report from a tertiary academic medical center. Cerebral white matter from autopsy material of a patient with gastrointestinal mantle-cell lymphoma who developed progressive multifocal leukoencephalopathy following rituximab therapy was evaluated by immunohistochemistry. Location-matched brain sections of patients with multiple sclerosis not treated with rituximab, patients without central nervous system disease, and patients with progressive multifocal leukoencephalopathy not associated with rituximab were used as controls. Assessment of the number of B lymphocytes in cerebral perivascular spaces in a patient with gastrointestinal mantle-cell lymphoma treated with rituximab, patients with multiple sclerosis, patients with progressive multifocal leukoencephalopathy not associated with rituximab, and healthy control subjects. We were unable to detect B cells in cerebral perivascular spaces of the patient who developed progressive multifocal leukoencephalopathy following rituximab therapy 8 months after her last dose. In contrast, B cells were detectable in all control brain tissues. To our knowledge, this is the first report to show B-lymphocyte depletion from brain tissue following rituximab therapy. A reduction in B-cell numbers may be an important contributing factor in the pathogenesis of central nervous system infections.

  20. Pathological changes in the structures of the blood-brain barrier in acute cerebral circulatory disorders

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    S. І. Tertyshny


    Full Text Available Morphological changes of the blood-brain barrier were investigated in case of an acute brain disturbed circulation. Autocontrol of vessels with their dilatation and formation of aggregation from formal elements were shown from the onset of the disease. Distructive changes of the endothelium, basement membranes, pericytes, asrtocytosal processes are marked in the microvessels with formation of the perivascular edema. Increase permeability of the blood-brain barrier promotes hemorrhagic transformation and lymphomicrophagical infi ltration of the perivascular zones.

  1. Perivascular adipose tissue, potassium channels, and vascular dysfunction. (United States)

    Tano, Jean-Yves; Schleifenbaum, Johanna; Gollasch, Maik


    Perivascular adipose tissue has been recognized unequivocally as a major player in the pathology of metabolic and cardiovascular diseases. Through its production of adipokines and the release of other thus far unidentified factors, this recently discovered adipose tissue modulates vascular regulation and the myogenic response. After the discovery of its ability to diminish the vessel's response to vasoconstrictors, a new paradigm established adipose-derived relaxing factor (ADRF) as a paracrine smooth muscle cells' potassium channel opener that could potentially help combat vascular dysfunction. This review will discuss the role of ADRF in vascular dysfunction in obesity and hypertension, the different potassium channels that can be activated by this factor, and describes new pharmacological tools that can mimic the ADRF effect and thus can be beneficial against vascular dysfunction in cardiovascular disease. © 2014 American Heart Association, Inc.

  2. Perivascular adipose tissue: more than just structural support. (United States)

    Szasz, Theodora; Webb, R Clinton


    PVAT (perivascular adipose tissue) has recently been recognized as a novel factor in vascular biology, with implications in the pathophysiology of cardiovascular disease. Composed mainly of adipocytes, PVAT releases a wide range of biologically active molecules that modulate vascular smooth muscle cell contraction, proliferation and migration. PVAT exerts an anti-contractile effect in various vascular beds which seems to be mediated by an as yet elusive PVRF [PVAT-derived relaxing factor(s)]. Considerable progress has been made on deciphering the nature and mechanisms of action of PVRF, and the PVRFs proposed until now are reviewed here. However, complex pathways seem to regulate PVAT function and more than one mechanism is probably responsible for PVAT actions in vascular biology. The present review describes our current knowledge on the structure and function of PVAT, with a focus on its role in modulating vascular tone. Potential involvements of PVAT dysfunction in obesity, hypertension and atherosclerosis will be highlighted.

  3. Perivascular spaces are associated with atherosclerosis: an insight from the Northern Manhattan Study. (United States)

    Gutierrez, J; Rundek, T; Ekind, M S V; Sacco, R L; Wright, C B


    Perivascular spaces are potential spaces found between brain blood vessels and surrounding leptomeninges that have been associated with cardiovascular risk factors and dementia, but less is known about their relationship to atherosclerosis. We tested the hypothesis that perivascular spaces are associated with atherosclerosis. Participants from the Northern Manhattan Study who remained stroke-free were invited to participate in an MR imaging substudy. Parenchymal hypointensities of spaces. A semiquantitative score was created to express the degree of brain involvement. Generalized linear models were used to assess statistical associations with carotid plaque as a surrogate marker of atherosclerosis. The studied sample included 706 participants (mean age, 72.6 ± 8.0 years; 60% women, 61% Hispanic, 68% with hypertension, 19% with diabetes, and 57% with high cholesterol). The perivascular spaces score ranged from 0 to 19 with 52% of the sample having a perivascular spaces score of ≤4. In unadjusted analysis, perivascular spaces were associated with age (β = 0.01 per year, P = spaces. Perivascular spaces were more frequently found in older participants, in those with hypertension, and in the presence of carotid plaque. These results suggest that mechanisms leading to atherosclerosis might also lead to an increased number of perivascular spaces. These results need confirmation in prospective studies.

  4. Survival-associated heterogeneity of marker-defined perivascular cells in colorectal cancer

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    Mezheyeuski, Artur; Lindh, Maja Bradic; Guren, Tormod Kyrre


    Perivascular cells (PC) were recently implied as regulators of metastasis and immune cell activity. Perivascular heterogeneity in clinical samples, and associations with other tumor features and outcome, remain largely unknown.Here we report a novel method for digital quantitative analyses...... to vessel density and size. Association studies implied specific oncogenic mutations in malignant cells as determinants of PC status. Semi-quantitative and digital-image-analyses-based scoring of the NORDIC-VII cohort identified significant associations between low expression of perivascular PDGFR-α and -β...

  5. Perivascular adipose tissue in the pathogenesis of cardiovascular disease. (United States)

    Lee, Hae-Young; Després, Jean-Pierre; Koh, Kwang Kon


    Adipose tissue, which has been considered mainly as a site of energy storage and mobilization, is found in many depots throughout the body. Adipose depots may have structural properties such as, for instance, the fat pads located in the hands and feet and the periorbital fat supporting the eyes. Adipose tissue also shows remarkable regional heterogeneity. For instance, substantial differences have been reported in the metabolic properties of visceral (intra-abdominal) vs. subcutaneous adipose depots. Visceral adipose tissue (VAT) has active endocrine and paracrine functions with the secretion of various pro-inflammatory chemokines potentially contributing to the progression of atherosclerosis related with obesity. In addition, adipose depots surrounding the heart, such as epicardial (EAT) and perivascular adipose tissues (PAT) may also exert important roles in the pathogenesis of cardiovascular disease beyond the contribution of VAT due to their close anatomic relationships with vascular structures and myocardium. The purpose of the present review is to outline the current understanding of the pathophysiological links between EAT, PAT and atherosclerotic cardiovascular disease. Also, we discuss the current investigative methods for PAT quantification and discuss the potential impact of PAT on cardiovascular risk prediction. Finally, potential clinical implications of these notions are discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  6. Perivascular fat, AMP-activated protein kinase and vascular diseases. (United States)

    Almabrouk, T A M; Ewart, M A; Salt, I P; Kennedy, S


    Perivascular adipose tissue (PVAT) is an active endocrine and paracrine organ that modulates vascular function, with implications for the pathophysiology of cardiovascular disease (CVD). Adipocytes and stromal cells contained within PVAT produce mediators (adipokines, cytokines, reactive oxygen species and gaseous compounds) with a range of paracrine effects modulating vascular smooth muscle cell contraction, proliferation and migration. However, the modulatory effect of PVAT on the vascular system in diseases, such as obesity, hypertension and atherosclerosis, remains poorly characterized. AMP-activated protein kinase (AMPK) regulates adipocyte metabolism, adipose biology and vascular function, and hence may be a potential therapeutic target for metabolic disorders such as type 2 diabetes mellitus (T2DM) and the vascular complications associated with obesity and T2DM. The role of AMPK in PVAT or the actions of PVAT have yet to be established, however. Activation of AMPK by pharmacological agents, such as metformin and thiazolidinediones, may modulate the activity of PVAT surrounding blood vessels and thereby contribute to their beneficial effect in cardiometabolic diseases. This review will provide a current perspective on how PVAT may influence vascular function via AMPK. We will also attempt to demonstrate how modulating AMPK activity using pharmacological agents could be exploited therapeutically to treat cardiometabolic diseases. © 2013 The British Pharmacological Society.

  7. The influence of perivascular adipose tissue on vascular homeostasis. (United States)

    Szasz, Theodora; Bomfim, Gisele Facholi; Webb, R Clinton


    The perivascular adipose tissue (PVAT) is now recognized as an active contributor to vascular function. Adipocytes and stromal cells contained within PVAT are a source of an ever-growing list of molecules with varied paracrine effects on the underlying smooth muscle and endothelial cells, including adipokines, cytokines, reactive oxygen species, and gaseous compounds. Their secretion is regulated by systemic or local cues and modulates complex processes, including vascular contraction and relaxation, smooth muscle cell proliferation and migration, and vascular inflammation. Recent evidence demonstrates that metabolic and cardiovascular diseases alter the morphological and secretory characteristics of PVAT, with notable consequences. In obesity and diabetes, the expanded PVAT contributes to vascular insulin resistance. PVAT-derived cytokines may influence key steps of atherogenesis. The physiological anticontractile effect of PVAT is severely diminished in hypertension. Above all, a common denominator of the PVAT dysfunction in all these conditions is the immune cell infiltration, which triggers the subsequent inflammation, oxidative stress, and hypoxic processes to promote vascular dysfunction. In this review, we discuss the currently known mechanisms by which the PVAT influences blood vessel function. The important discoveries in the study of PVAT that have been made in recent years need to be further advanced, to identify the mechanisms of the anticontractile effects of PVAT, to explore the vascular-bed and species differences in PVAT function, to understand the regulation of PVAT secretion of mediators, and finally, to uncover ways to ameliorate cardiovascular disease by targeting therapeutic approaches to PVAT.

  8. Changes in the population of perivascular cells in the bone tissue remodeling zones under microgravity (United States)

    Katkova, Olena; Rodionova, Natalia; Shevel, Ivan


    Microgravity and long-term hypokinesia induce reduction both in bone mass and mineral saturation, which can lead to the development of osteoporosis and osteopenia. (Oganov, 2003). Reorganizations and adaptive remodeling processes in the skeleton bones occur in the topographical interconnection with blood capillaries and perivascular cells. Radioautographic studies with 3H- thymidine (Kimmel, Fee, 1980; Rodionova, 1989, 2006) have shown that in osteogenesis zones there is sequential differentiation process of the perivascular cells into osteogenic. Hence the study of populations of perivascular stromal cells in areas of destructive changes is actual. Perivascular cells from metaphysis of the rat femoral bones under conditions of modeling microgravity were studied using electron microscopy and cytochemistry (hindlimb unloading, 28 days duration) and biosatellite «Bion-M1» (duration of flight from April 19 till May 19, 2013 on C57, black mice). It was revealed that both control and test groups populations of the perivascular cells are not homogeneous in remodeling adaptive zones. These populations comprise of adjacent to endothelium poorly differentiated forms and isolated cells with signs of differentiation (specific increased volume of rough endoplasmic reticulum in cytoplasm). Majority of the perivascular cells in the control group (modeling microgravity) reveals reaction to alkaline phosphatase (marker of the osteogenic differentiation). In poorly differentiated cells this reaction is registered in nucleolus, nucleous and cytoplasm. In differentiating cells activity of the alkaline phosphatase is also detected on the outer surface of the cellular membrane. Unlike the control group in the bones of experimental animals reaction to the alkaline phosphatase is registered not in all cells of perivascular population. Part of the differentiating perivascular cells does not contain a product of the reaction. Under microgravity some poorly differentiated perivascular

  9. Effect of Nerve Growth Factor on Innervation of Perivascular Nerves in Neovasculatures of Mouse Cornea. (United States)

    Matsuyama, Akiko; Takatori, Shingo; Sone, Yoko; Ochi, Eiko; Goda, Mitsuhiro; Zamami, Yoshito; Hashikawa-Hobara, Narumi; Kitamura, Yoshihisa; Kawasaki, Hiromu


    Angiogenesis, which is the generation of new vascular networks from existing blood vessels, occurs under normal and pathophysiological conditions. Perivascular nerves, which innervate mature vasculatures, maintain vascular tone and regulate tissue blood flow. However, little is known whether perivascular nerves innervate newborn blood vessels. Therefore, the aim of this study was to investigate the distribution and characterization of perivascular nerves in neovasculatures, which were generated by the mouse corneal micropocket method. Under anesthesia, a pellet containing basic fibroblast growth factor (bFGF) (100 ng/pellet) was implanted into a mouse cornea in one side of the eyeball. Nerve growth factor (NGF) was locally (2 or 20 ng) applied with the pellet, or subcutaneously (40 ng/h for 7 d) administered with an osmotic mini-pump. After the implantation, vascular endothelial cells, smooth muscle cells, and perivascular nerves in the cornea were immunohistochemically studied. Neovessels generated from existing limbal vessels were observed in pellet-implanted cornea. Immunostaining of neovasculatures showed the presence of CD31-like immunoreactive (LI) endothelial cells and α-smooth muscle actin-LI vascular smooth muscles. Perivascular nerves immunostained by protein gene product (PGP) 9.5, an axonal marker, were found in the existing limbal vessels, but they were not observed in neovasculatures. Local and subcutaneous treatment of NGF inhibits bFGF-derived angiogenesis and resulted in loop-shaped vessels that had many anastomoses, and produced innervation of PGP 9.5-LI perivascular nerves around bFGF-derived neovessels. These findings suggest that neovasculatures have no innervation of perivascular nerves, and that NGF facilitates innervations of perivascular nerves to regulate the blood flow in neovessels.

  10. Microscopic endometrial perivascular epithelioid cell nodules: a case report with the earliest presentation of a uterine perivascular epithelioid cell tumor

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    Fang Chia-Lang


    Full Text Available Abstract Perivascular epithelioid cell (PEC tumors (PEComas are a family of related mesenchymal tumors composed of PECs which co-express melanocytic and smooth muscle markers. Although their distinctive histologic, immunohistochemical, ultrastructural, and genetic features have been clearly demonstrated, their histogenesis and normal counterpart remain largely unknown. Precursor lesions of PEComas have rarely been reported. We herein describe a tuberous sclerosis patient with microscopic PEC nodules in the endometrium of adenomyosis, pelvic endometriosis, an ovarian endometriotic cyst, and the endometrium of the uterine cavity. The nodules showed a mixture of spindle-shaped and epithelioid cells concentrically arranged around small arteries. The cells exhibited uniform nuclei, light eosinophilic cytoplasm, and immunoreactivity with HMB-45 and CD10. Some nodules revealed continuity with a PEComa in the myometrium. These findings support microscopic endometrial PEC nodules possibly being precursor lesions of uterine PEComas. The wide distribution of the nodules in the pelvis may be related to the multicentricity of PEComas in tuberous sclerosis patients. Owing to the immunoreactivity with CD10, microscopic endometrial PEC nodules may be misinterpreted as endothelial stromal cells unless melanocytic markers are stained. To the best of our knowledge, this is a case with the earliest manifestation of PEC lesions occurring in the endometrium. Virtual Slides The virtual slide(s for this article can be found here:

  11. The influence of perivascular adipose tissue on vascular homeostasis

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    Szasz T


    Full Text Available Theodora Szasz,1 Gisele Facholi Bomfim,2 R Clinton Webb1 1Department of Physiology, Georgia Regents University, Augusta, USA; 2Department of Pharmacology, University of São Paulo, São Paulo, Brazil Abstract: The perivascular adipose tissue (PVAT is now recognized as an active contributor to vascular function. Adipocytes and stromal cells contained within PVAT are a source of an ever-growing list of molecules with varied paracrine effects on the underlying smooth muscle and endothelial cells, including adipokines, cytokines, reactive oxygen species, and gaseous compounds. Their secretion is regulated by systemic or local cues and modulates complex processes, including vascular contraction and relaxation, smooth muscle cell proliferation and migration, and vascular inflammation. Recent evidence demonstrates that metabolic and cardiovascular diseases alter the morphological and secretory characteristics of PVAT, with notable consequences. In obesity and diabetes, the expanded PVAT contributes to vascular insulin resistance. PVAT-derived cytokines may influence key steps of atherogenesis. The physiological anticontractile effect of PVAT is severely diminished in hypertension. Above all, a common denominator of the PVAT dysfunction in all these conditions is the immune cell infiltration, which triggers the subsequent inflammation, oxidative stress, and hypoxic processes to promote vascular dysfunction. In this review, we discuss the currently known mechanisms by which the PVAT influences blood vessel function. The important discoveries in the study of PVAT that have been made in recent years need to be further advanced, to identify the mechanisms of the anticontractile effects of PVAT, to explore the vascular-bed and species differences in PVAT function, to understand the regulation of PVAT secretion of mediators, and finally, to uncover ways to ameliorate cardiovascular disease by targeting therapeutic approaches to PVAT. Keywords: adipokines

  12. Human bone perivascular niche-on-a-chip for studying metastatic colonization. (United States)

    Marturano-Kruik, Alessandro; Nava, Michele Maria; Yeager, Keith; Chramiec, Alan; Hao, Luke; Robinson, Samuel; Guo, Edward; Raimondi, Manuela Teresa; Vunjak-Novakovic, Gordana


    Eight out of 10 breast cancer patients die within 5 years after the primary tumor has spread to the bones. Tumor cells disseminated from the breast roam the vasculature, colonizing perivascular niches around blood capillaries. Slow flows support the niche maintenance by driving the oxygen, nutrients, and signaling factors from the blood into the interstitial tissue, while extracellular matrix, endothelial cells, and mesenchymal stem cells regulate metastatic homing. Here, we show the feasibility of developing a perfused bone perivascular niche-on-a-chip to investigate the progression and drug resistance of breast cancer cells colonizing the bone. The model is a functional human triculture with stable vascular networks within a 3D native bone matrix cultured on a microfluidic chip. Providing the niche-on-a-chip with controlled flow velocities, shear stresses, and oxygen gradients, we established a long-lasting, self-assembled vascular network without supplementation of angiogenic factors. We further show that human bone marrow-derived mesenchymal stem cells, which have undergone phenotypical transition toward perivascular cell lineages, support the formation of capillary-like structures lining the vascular lumen. Finally, breast cancer cells exposed to interstitial flow within the bone perivascular niche-on-a-chip persist in a slow-proliferative state associated with increased drug resistance. We propose that the bone perivascular niche-on-a-chip with interstitial flow promotes the formation of stable vasculature and mediates cancer cell colonization.

  13. [Dilatation of Virchow-Robin perivascular spaces (types III cerebral lacunae): radio-clinical correlations]. (United States)

    Marnet, D; Noudel, R; Peruzzi, P; Bazin, A; Bernard, M H; Scherpereel, B; Pluot, M; Rousseaux, P


    Virchow-Robin spaces are pia-lined extensions of the subarachnoid space surrounding the path of brain vessels. When enlarged, such dilated perivascular spaces are often seen as foci of cerebrospinal fluid signal on MRI or CT scan. These foci are found in patients with miscellaneous clinical status. It is necessary to determine the radiological significance and clinical associations, if any, in such patients in order to give them the appropriate treatment. We describe the clinical and radiological findings of five patients and review the literature on perivascular Virchow-Robin spaces. The mechanisms of dilated Virchow-Robin spaces are still not well understood. Such dilated perivascular spaces are found in two locations: typically in the high-convexity white matter of healthy elderly subjects, or surrounding the lenticulostriate vessels as they enter the basal ganglia. On MR images, they may be confused with lacunar infarcts. Most of the patients present with no symptoms: small dilatations located in the high convexity actually represent an anatomic variant, also called "état criblé". Sometimes, giant dilatations, or Poirier's type IIIb "expanding lacunae", found in the basal ganglia and midbrain may result in symptomatic hydrocephalus needing appropriate treatment. For other miscellaneous symptoms as headache, generalized epilepsy, dysmorphy, macrocephaly, there is no reliable correlation with enlarged perivascular spaces seen on MR images. The real symptomatic dilated perivascular spaces need appropriate and quick treatment. Most of the other patients present with no symptoms and will remain asymptomatic.

  14. The perivascular phagocyte of the mouse pineal gland: An antigen-presenting cell

    DEFF Research Database (Denmark)

    Møller, Morten; Rath, Martin F; Klein, David C


    The perivascular space of the rat pineal gland is known to contain phagocytic cells that are immunoreactive for leukocyte antigens, and thus they appear to belong to the macrophage/microglial cell line. These cells also contain MHC class II proteins. We investigated this cell type in the pineal...... gland of mice. Actively phagocytosing cells with a prominent lysosomal system were found in the pericapillary spaces of the mouse pineal gland following intravenous injection of horseradish peroxidase. The cells also exhibited strong acid phosphatase activity. Perivascular cells were immunopositive...... for MHC class II protein and for CD68, a marker of monocytes/phagocytes. This study verifies that perivascular phagocytes with antigen-presenting properties are present in the mouse pineal gland....

  15. A patient presenting with a perivascular epithelioid cell tumor in the broad ligament: a case report

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    Ross Claire


    Full Text Available Abstract Introduction Perivascular epithelioid cell tumors are a family of rare mesenchymal tumors composed of histologically and immunohistochemically distinctive perivascular epithelioid cells. They can originate in any visceral organ or soft tissue and include a range of lesions such as angiomyolipoma, clear cell 'sugar' tumor of the lung, lymphangioleiomyomatosis and clear cell myomelanocytic tumors of the falciparum ligament/ligament teres. Due to their rarity and varied sites and presentation, management of these tumors remains highly challenging. Case Presentation A 46-year-old para 2 Caucasian woman initially presented to the general surgeons at our hospital in North West London with abdominal pain. Laparoscopy revealed a right broad ligament hematoma, which was thought to be iatrogenic in origin, from insertion of the Veress needle at the time of surgery, and was managed conservatively. Upon her re-presentation two months later with severe pain, ultrasound scanning revealed the hematoma had increased in size and she underwent a total abdominal hysterectomy and bilateral salpingo-oophorectomy. Histology results from necrotic tissue from the hematoma led to a diagnosis of perivascular epithelioid cell tumor. She was then referred to a tertiary oncology center, where she underwent several further operations in an attempt to debulk the tumor for symptomatic relief of her pain, with limited success. She is now taking the immunosuppressive drug sirolimus, which has produced a modest reduction in tumor size. She is now 47 months on from initial presentation. Conclusions A literature search has revealed only six other case reports of broad ligament perivascular epithelioid cell tumors, with varied presentations and management. The longest duration of follow-up was 21 months. Only five other cases of perivascular epithelioid cell tumor managed with sirolimus have been reported. We therefore feel that this report highlights some of the

  16. Presumed toxoplasmic central retinal artery occlusion and multifocal retinitis with perivascular sheathing

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    Arai H


    Full Text Available Haruka Arai,1 Tsutomu Sakai,1 Kiichiro Okano,1 Ranko Aoyagi,1 Ayano Imai,2 Hiroshi Takase,2 Manabu Mochizuki,2 Hiroshi Tsuneoka11Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan; 2Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, JapanAbstract: Central retinal artery occlusion (CRAO and multifocal retinitis with perivascular sheathing are rare in ocular toxoplasmosis. We report a case of toxoplasmic CRAO and multifocal retinitis with perivascular sheathing. A healthy 83-year-old male developed left panuveitis. Funduscopic examination of the left eye showed a swollen optic disc and sheathing of the retinal artery with a dense vitreous haze and a white retinal lesion. Serum anti-toxoplasma antibodies were positive in a latex agglutination assay. Vitrectomy was performed to improve visualization of the retinal lesions and for examination of causative microorganisms. A postoperative fundus examination revealed CRAO with optic disc involvement and multifocal retinitis with perivascular sheathing. Qualitative multiplex polymerase chain reaction detected the Toxoplasma gondii B1 gene in ocular fluid from both the aqueous and vitreous humor. The presumed diagnosis of ocular toxoplasmosis was made and treatment was started with prednisone and acetylspiramycin with subsequent improvement. Two months later, the patient developed active retinochoroiditis in the left eye. After 6 weeks of anti-toxoplasma therapy, the disease involuted. Retinal vascular occlusions and multifocal retinitis with perivascular sheathing are rare in toxoplasmosis. This is the first case report of toxoplasmic CRAO and multifocal retinitis with perivascular sheathing. The diagnosis of ocular toxoplasmosis should be considered in patients with retinal artery occlusions and multifocal retinitis with perivascular sheathing associated with inflammation.Keywords: ocular toxoplasmosis, toxoplasma retinochoroiditis

  17. Rare Association of Perivascular Granulomatous Lesions in a Patient with Acute Retinal Necrosis

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    Takahiro Sogawa


    Full Text Available Purpose: The aim of this study was to examine sequential changes in perivascular granulomatous lesions with acute retinal necrosis (ARN. Methods: A healthy 46-year-old Japanese woman, who developed floaters and pain in her left eye, underwent optical coherence tomography (OCT, fluorescein angiography, and routine ophthalmological examinations. Treatment-associated changes in perivascular granulomatous lesions were monitored using spectral-domain (SD-OCT. Results: The patient had no previous ophthalmic history, and her general condition was good. A slit-lamp examination revealed keratic precipitates and aqueous cells (2+ in the left eye. A fundus examination showed yellow-white patches of necrotizing retinal lesions in the temporal upper area, retinal arteritis, retinal hemorrhage, and vitreous opacities. The patient was diagnosed with ARN according to diagnostic criteria. SD-OCT images confirmed high-intensity and uniform granulomatous deposits in the perivascular area and fovea. Systemic corticosteroids and antiviral therapy were initiated, resulting in the gradual resolution of granulomatous lesions. The patient continues to be followed untreated without evidence of recurrence, retinal detachment, or active inflammation. Conclusions: This is the first report of perivascular granulomatous lesions in a patient with ARN. Our results showed that the formation of granulomas may be induced in the retina of ARN patients without fulminant inflammation.

  18. The pathological structure of the perivascular niche in different microvascular patterns of glioblastoma.

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    Jintao Chen

    Full Text Available The perivascular niche is critical for intercellular communication between resident cell types in glioblastoma (GBM, and it plays a vital role in maintaining the glioma stem cell (GSC microenvironment. It is shown in abundant research that different microvascular patterns exist in GBM; and it can be implied that different microvascular patterns are associated with different pathological structures in the perivascular niche. However, the pathological structure of the perivascular niche is still not clear. Here, we investigated the distribution and biological characteristics of different microvascular pattern niches (MVPNs in GBM by detecting the expression of CD34, CD133, Nestin, α-SMA, GFAP and CD14 in the perivascular niche using multiple -fluorescence. The four basic microvascular patterns are microvascular sprouting (MS, vascular cluster (VC, vascular garland (VG, and glomeruloid vascular proliferation (GVP. By analyzing the proportion of the area of each marker in four types of formations, the results indicated that the expression of CD34, CD133 and Nestin in MS and VC was significantly lower than that in VG and GVP (P0.05. According to the area distributions of different markers, we mapped four precise simulation diagrams to provide an effective foundation for the accurate simulation of glioblastoma in vitro.

  19. Perivascular epithelioid cell tumor of gastrointestinal tract: case report and review of the literature

    NARCIS (Netherlands)

    Lu, B.; Wang, C.; Zhang, J.; Kuiper, R.P.; Song, M.; Zhang, X.; Song, S.; Geurts van Kessel, A.; Iwamoto, A.; Wang, J; Liu, H.


    Perivascular epithelioid cell tumors of gastrointestinal tract (GI PEComas) are exceedingly rare, with only a limited number of published reports worldwide. Given the scarcity of GI PEComas and their relatively short follow-up periods, our current knowledge of their biologic behavior, molecular

  20. Cold exposure down-regulates immune response pathways in ferret aortic perivascular adipose tissue

    NARCIS (Netherlands)

    Reynés, Bàrbara; Schothorst, van Evert M.; García-Ruiz, Estefanía; Keijer, Jaap; Palou, Andreu; Oliver, Paula


    Perivascular adipose tissue (PVAT) surrounds blood vessels and releases paracrine factors, such as cytokines, which regulate local inflammation. The inflammatory state of PVAT has an important role in vascular disease; a pro-inflammatory state has been related with atherosclerosis development,

  1. Association of Perivascular Localization of Aquaporin-4 With Cognition and Alzheimer Disease in Aging Brains. (United States)

    Zeppenfeld, Douglas M; Simon, Matthew; Haswell, J Douglas; D'Abreo, Daryl; Murchison, Charles; Quinn, Joseph F; Grafe, Marjorie R; Woltjer, Randall L; Kaye, Jeffrey; Iliff, Jeffrey J


    Cognitive impairment and dementia, including Alzheimer disease (AD), are common within the aging population, yet the factors that render the aging brain vulnerable to these processes are unknown. Perivascular localization of aquaporin-4 (AQP4) facilitates the clearance of interstitial solutes, including amyloid-β, through the brainwide network of perivascular pathways termed the glymphatic system, which may be compromised in the aging brain. To determine whether alterations in AQP4 expression or loss of perivascular AQP4 localization are features of the aging human brain and to define their association with AD pathology. Expression of AQP4 was analyzed in postmortem frontal cortex of cognitively healthy and histopathologically confirmed individuals with AD by Western blot or immunofluorescence for AQP4, amyloid-β 1-42, and glial fibrillary acidic protein. Postmortem tissue and clinical data were provided by the Oregon Health and Science University Layton Aging and Alzheimer Disease Center and Oregon Brain Bank. Postmortem tissue from 79 individuals was evaluated, including cognitively intact "young" individuals aged younger than 60 years (range, 33-57 years), cognitively intact "aged" individuals aged older than 60 years (range, 61-96 years) with no known neurological disease, and individuals older than 60 years (range, 61-105 years) of age with a clinical history of AD confirmed by histopathological evaluation. Forty-eight patient samples (10 young, 20 aged, and 18 with AD) underwent histological analysis. Sixty patient samples underwent Western blot analysis (15 young, 24 aged, and 21 with AD). Expression of AQP4 protein, AQP4 immunoreactivity, and perivascular AQP4 localization in the frontal cortex were evaluated. Expression of AQP4 was associated with advancing age among all individuals (R2 = 0.17; P = .003). Perivascular AQP4 localization was significantly associated with AD status independent of age (OR, 11.7 per 10% increase in localization; z

  2. Macropinocytosis of Bevacizumab by Glioblastoma Cells in the Perivascular Niche Affects their Survival. (United States)

    Müller-Greven, Gaëlle; Carlin, Cathleen R; Burgett, Monica E; Ahluwalia, Manmeet S; Lauko, Adam; Nowacki, Amy S; Herting, Cameron J; Qadan, Maha A; Bredel, Markus; Toms, Steven A; Lathia, Justin D; Hambardzumyan, Dolores; Sarkaria, Jann N; Hamerlik, Petra; Gladson, Candece L


    Purpose: Bevacizumab, a humanized monoclonal antibody to VEGF, is used routinely in the treatment of patients with recurrent glioblastoma (GBM). However, very little is known regarding the effects of bevacizumab on the cells in the perivascular space in tumors. Experimental Design: Established orthotopic xenograft and syngeneic models of GBM were used to determine entry of monoclonal anti-VEGF-A into, and uptake by cells in, the perivascular space. Based on the results, we examined CD133 + cells derived from GBM tumors in vitro Bevacizumab internalization, trafficking, and effects on cell survival were analyzed using multilabel confocal microscopy, immunoblotting, and cytotoxicity assays in the presence/absence of inhibitors. Results: In the GBM mouse models, administered anti-mouse-VEGF-A entered the perivascular tumor niche and was internalized by Sox2 + /CD44 + tumor cells. In the perivascular tumor cells, bevacizumab was detected in the recycling compartment or the lysosomes, and increased autophagy was found. Bevacizumab was internalized rapidly by CD133 + /Sox2 + -GBM cells in vitro through macropinocytosis with a fraction being trafficked to a recycling compartment, independent of FcRn, and a fraction to lysosomes. Bevacizumab treatment of CD133 + GBM cells depleted VEGF-A and induced autophagy thereby improving cell survival. An inhibitor of lysosomal acidification decreased bevacizumab-induced autophagy and increased cell death. Inhibition of macropinocytosis increased cell death, suggesting macropinocytosis of bevacizumab promotes CD133 + cell survival. Conclusions: We demonstrate that bevacizumab is internalized by Sox2 + /CD44 + -GBM tumor cells residing in the perivascular tumor niche. Macropinocytosis of bevacizumab and trafficking to the lysosomes promotes CD133 + cell survival, as does the autophagy induced by bevacizumab depletion of VEGF-A. Clin Cancer Res; 23(22); 7059-71. ©2017 AACR . ©2017 American Association for Cancer Research.

  3. Malignant TFE3-rearranged perivascular epithelioid cell neoplasm (PEComa) presenting as a subcutaneous mass. (United States)

    Shon, W; Kim, J; Sukov, W; Reith, J


    Perivascular epithelioid cell neoplasms (PEComas) are a group of mesenchymal tumours with concurrent melanocytic and myogenic differentiation. Although many cases are sporadic, PEComas can be associated with tuberous sclerosis. A distinct subset of deep-seated PEComas has been shown to carry TFE3 fusions. To our knowledge, this is the first reported case of primary subcutaneous malignant PEComa with molecular confirmation of TFE3 gene rearrangement. © 2015 British Association of Dermatologists.

  4. Loss of anti-contractile effect of perivascular adipose tissue in offspring of obese rats


    Zaborska, Wareing; Wareing, Mark; Edwards, Austin


    Rationale: Maternal obesity pre-programmes offspring to develop obesity and associated cardiovascular disease. Perivascular adipose tissue (PVAT) exerts an anti-contractile effect on the vasculature, which is reduced in hypertension and obesity. Objective: The objective of this study was to determine whether maternal obesity pre-programmes offspring to develop PVAT dysfunction in later life. Methods: Female Sprague?Dawley rats were fed a diet containing 10% (control) or 45% fat (high fat diet...

  5. Obesity-related hypertension: epidemiology, pathophysiology, treatments, and the contribution of perivascular adipose tissue. (United States)

    Aghamohammadzadeh, Reza; Heagerty, Anthony M


    The advent of the obesity epidemic has highlighted the need to re-assess more closely the pathophysiology of obesity-related hypertension with the aim of identifying new therapies. In this article, we review the role of the renin-angiotensin-aldosterone system, sympathetic nervous system, and inflammation in relation to the pathophysiology of this condition. We also discuss the potential role of the perivascular adipose tissue in the context of obesity-related hypertension.

  6. A macrophage phenotype for a constitutive, class II antigen-expressing, human dermal perivascular dendritic cell. (United States)

    Sontheimer, R D; Matsubara, T; Seelig, L L


    A previously uncharacterized population of class II antigen-bearing dendritic cells that are intimately associated with the dermal microvasculature was identified in normal human skin using a double-label, indirect immunofluorescence technique. The only other major HLA-DR positive dermal cell type noted in these studies, the dermal microvascular endothelial cell (DMVEC), appeared to express lesser amounts of HLA-DR region gene product than did this dermal perivascular dendritic cell (DPDC). These DPDC were particularly common around small vessels in the superficial vascular plexus of the papillary dermis and were distinct from the mast cell, another cell type normally seen in a similar location. Phenotypic and ultrastructural studies have determined that the DPDC is more closely related to the monocyte/macrophage lineage than the dendritic cell lineage. The perivascular location and phenotype of this cell distinguishes it from other previously described constitutive dermal cell types such as the classic "histiocyte," veiled cell, and dendrocyte. The relatively rich expression of all three major HLA-D region gene products by this dermal perivascular dendritic macrophage would suggest that it could play a significant role in the immunobiology of the dermal microvascular unit.

  7. Perivascular delivery of Notch 1 siRNA inhibits injury-induced arterial remodeling.

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    Eileen M Redmond

    Full Text Available To determine the efficacy of perivascular delivery of Notch 1 siRNA in preventing injury-induced arterial remodeling.Carotid artery ligation was performed to induce arterial remodeling. After 14 days, morphometric analysis confirmed increased vSMC growth and subsequent media thickening and neointimal formation. Laser capture microdissection, quantitative qRT-PCR and immunoblot analysis of medial tissue revealed a significant increase in Notch1 receptor and notch target gene, Hrt 1 and 2 expression in the injured vessels. Perivascular delivery of Notch 1 siRNA by pluronic gel inhibited the injury-induced increase in Notch 1 receptor and target gene expression when compared to scrambled siRNA controls while concomitantly reducing media thickening and neointimal formation to pre-injury, sham-operated levels. Selective Notch 1 knockdown also reversed the injury-induced inhibition of pro-apoptotic Bax expression while decreasing injury-induced anti-apoptotic Bcl-XL expression to sham-operated control levels. In parallel experiments, proliferative cyclin levels, as measured by PCNA expression, were reversed to sham-operated control levels following selective Notch 1 knockdown.These results suggest that injury-induced arterial remodeling can be successfully inhibited by localized perivascular delivery of Notch 1 siRNA.

  8. Vascular neuropeptide Y contributes to atherosclerotic plaque progression and perivascular mast cell activation. (United States)

    Lagraauw, H Maxime; Westra, Marijke M; Bot, Martine; Wezel, Anouk; van Santbrink, Peter J; Pasterkamp, Gerard; Biessen, Erik A L; Kuiper, Johan; Bot, Ilze


    Neuropeptide Y is an abundantly expressed neurotransmitter capable of modulating both immune and metabolic responses related to the development of atherosclerosis. NPY receptors are expressed by a number of vascular wall cell types, among which mast cells. However, the direct effects of NPY on atherosclerotic plaque development and progression remain to be investigated. In this study we thus aimed to determine whether NPY is expressed in atherosclerotic plaques and to establish its role in atherosclerotic plaque development. NPY expression was seen to be increased up to 2-fold in unstable human endarterectomy plaques, as compared to stable plaques, and to be significantly upregulated during lesion progression in apoE(-/-) mice. In apoE(-/-) mice focal overexpression of NPY in the carotid artery significantly increased atherosclerotic plaque size compared to controls, while plaque composition was unaffected. Interestingly, perivascular mast cell activation was significantly higher in the NPY-overexpressing mice, suggesting that NPY may impact plaque progression in part via mast cell activation. Furthermore, in vitro NPY-induced murine mast cell activation resulted in the release of pro-atherogenic mediators including IL-6 and tryptase. Our data show that NPY expression is increased during atherogenesis and in particular in unstable plaques. Furthermore, perivascular overexpression of NPY promoted plaque development and perivascular mast cell activation, suggestive of a role for NPY-induced mast cell activation in lesion progression. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  9. Culture media-based selection of endothelial cells, pericytes, and perivascular-resident macrophage-like melanocytes from the young mouse vestibular system. (United States)

    Zhang, Jinhui; Chen, Songlin; Cai, Jing; Hou, Zhiqiang; Wang, Xiaohan; Kachelmeier, Allan; Shi, Xiaorui


    The vestibular blood-labyrinth barrier (BLB) is comprised of perivascular-resident macrophage-like melanocytes (PVM/Ms) and pericytes (PCs), in addition to endothelial cells (ECs) and basement membrane (BM), and bears strong resemblance to the cochlear BLB in the stria vascularis. Over the past few decades, in vitro cell-based models have been widely used in blood-brain barrier (BBB) and blood-retina barrier (BRB) research, and have proved to be powerful tools for studying cell-cell interactions in their respective organs. Study of both the vestibular and strial BLB has been limited by the unavailability of primary culture cells from these barriers. To better understand how barrier component cells interact in the vestibular system to control BLB function, we developed a novel culture medium-based method for obtaining EC, PC, and PVM/M primary cells from tiny explants of the semicircular canal, sacculus, utriculus, and ampullae tissue of young mouse ears at post-natal age 8-12 d. Each phenotype is grown in a specific culture medium which selectively supports the phenotype in a mixed population of vestibular cell types. The unwanted phenotypes do not survive passaging. The protocol does not require additional equipment or special enzyme treatment. The harvesting process takes less than 2 h. Primary cell types are generated within 7-10 d. The primary culture ECs, PCs, and PVM/M shave consistent phenotypes more than 90% pure after two passages (∼ 3 weeks). The highly purified primary cell lines can be used for studying cell-cell interactions, barrier permeability, and angiogenesis. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Topical application of sodium hyaluronate for preventing perivascular adhesion of the vein grafts in rabbits: An experimental study

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    Ming-ke GUO


    Full Text Available Objective To explore the effect of topical application of sodium hyaluronate on preventing perivascular adhesion of the vein grafts in rabbits. Methods Thirty-six male New Zealand white rabbits, aged 5 months, were randomly and equally divided into 2 groups: groups A and B. Arterial defect model was established by cutting about 1cm artery from the middle part of the dissected left common carotid artery. A section about 3cm was cut from the right external jugular vein, and the harvested vein was inverted and anastomosed end-to-end to the artery defect. After the anastomosis, the adventitia and two anastomoses of the grafted veins in group A were coated locally with 0.2ml sodium hyaluronate. The grafted veins were obtained 1, 2 and 4 weeks after the operation, with the perivascular adhesion of the vein grafts being examined macroscopically before the resection. HE staining and Masson staining were preformed for histological changes of grafted vein wall and the perivascular adhesion of the vein grafts. At 2, 4 weeks postoperation, the perivascular adhesions of the vein grafts were graded by the grading criteria of adhesion in macroscopic evaluation and histological evaluation. Results At 1, 2 and 4 weeks postoperatively, the macroscopic and histological observation found that the perivascular adhesions in group A were looser than those in group B. The macroscopic grade and histological grade were lower in group A than in group B, there was a significant difference between the two groups at 2 and 4 weeks postoperation (P<0.05. Conclusion Topical application of sodium hyaluronate can reduce the perivascular adhesion and is an ideal treatment strategy for preventing perivascular adhesion of vein grafts. DOI: 10.11855/j.issn.0577-7402.2017.08.14

  11. Protons modulate perivascular axo-axonal neurotransmission in the rat mesenteric artery. (United States)

    Takatori, Shingo; Hirai, Kazuhiro; Ozaki, Shuichiro; Tangsucharit, Panot; Fukushima-Miyashita, Satoko; Goda, Mitsuhiro; Hashikawa-Hobara, Narumi; Ono, Nobufumi; Kawasaki, Hiromu


    Previous studies have demonstrated that nicotine releases protons from adrenergic nerves via stimulation of nicotinic ACh receptors and activates transient receptor potential vanilloid-1 (TRPV1) receptors located on calcitonin gene-related peptide (CGRP)-containing (CGRPergic) vasodilator nerves, resulting in vasodilatation. The present study investigated whether perivascular nerves release protons, which modulate axon-axonal neurotransmission. Perfusion pressure and pH levels of perfusate in rat-perfused mesenteric vascular beds without endothelium were measured with a pressure transducer and a pH meter respectively. Periarterial nerve stimulation (PNS) initially induced vasoconstriction, which was followed by long-lasting vasodilatation and decreased pH levels in the perfusate. Cold-storage denervation of the preparation abolished the decreased pH and vascular responses to PNS. The adrenergic neuron blocker guanethidine inhibited PNS-induced vasoconstriction and effects on pH, but not PNS-induced vasodilatation. Capsaicin (CGRP depletor), capsazepine and ruthenium red (TRPV1 inhibitors) attenuated the PNS-induced decrease in pH and vasodilatation. In denuded preparations, ACh caused long-lasting vasodilatation and lowered pH; these effects were inhibited by capsaicin pretreatment and atropine, but not by guanethidine or mecamylamine. Capsaicin injection induced vasodilatation and a reduction in pH, which were abolished by ruthenium red. The use of a fluorescent pH indicator demonstrated that application of nicotine, ACh and capsaicin outside small mesenteric arteries reduced perivascular pH levels and these effects were abolished in a Ca(2+) -free medium. These results suggest that protons are released from perivascular adrenergic and CGRPergic nerves upon PNS and these protons modulate transmission in CGRPergic nerves. © 2014 The British Pharmacological Society.

  12. Temporal changes in perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin after subarachnoid hemorrhage. (United States)

    Pluta, R M; Afshar, J K; Boock, R J; Oldfield, E H


    Hemoglobin released from hemolysed erythrocytes has been postulated to be responsible for delayed cerebral vasospasm after subarachnoid hemorrhage (SAH). However, the evidence is indirect and the mechanisms of action are unclear. Cerebrovascular tone is regulated by a dynamic balance of relaxing and contracting factors. Loss of the endothelium-derived relaxing factor-nitric oxide in the presence of oxyhemoglobin and overproduction of endothelin-1 stimulated by oxyhemoglobin have been postulated as causes of delayed cerebral vasospasm after SAH. The authors aimed to investigate this hypothesis using in vivo microdialysis to examine time-dependent changes in the perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin in a primate model of SAH. Nine cynomolgus monkeys underwent right-sided frontotemporal craniectomy and placement of a semipermeable microdialysis catheter adjacent to the right middle cerebral artery (MCA). Saline (control group, three animals) or an arterial blood clot (SAH group, six animals) was then placed around the MCA and the catheter. Arteriographically confirmed vasospasm had developed in all animals with SAH but in none of the control animals on Day 7. The dialysate was collected daily for 12 days. Levels of oxyhemoglobin, deoxyhemoglobin, and methemoglobin were measured by means of spectrophotometry. Perivascular concentrations of oxyhemoglobin, deoxyhemoglobin, and methemoglobin peaked on Day 2 in the control monkeys and could not be detected on Days 5 to 12. Perivascular concentrations of oxyhemoglobin and deoxyhemoglobin peaked on Day 7 in the SAH group, at which time the concentrations in the dialysate were 100-fold higher than in any sample obtained from the control animals. Methemoglobin levels increased only slightly, peaking between Days 7 and 12, at which time the concentration in the dialysate was 10-fold higher than in samples from the control animals. This study provides in vivo evidence that the

  13. Constitutively active Notch1 converts cranial neural crest-derived frontonasal mesenchyme to perivascular cells in vivo

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    Sophie R. Miller


    Full Text Available Perivascular/mural cells originate from either the mesoderm or the cranial neural crest. Regardless of their origin, Notch signalling is necessary for their formation. Furthermore, in both chicken and mouse, constitutive Notch1 activation (via expression of the Notch1 intracellular domain is sufficient in vivo to convert trunk mesoderm-derived somite cells to perivascular cells, at the expense of skeletal muscle. In experiments originally designed to investigate the effect of premature Notch1 activation on the development of neural crest-derived olfactory ensheathing glial cells (OECs, we used in ovo electroporation to insert a tetracycline-inducible NotchΔE construct (encoding a constitutively active mutant of mouse Notch1 into the genome of chicken cranial neural crest cell precursors, and activated NotchΔE expression by doxycycline injection at embryonic day 4. NotchΔE-targeted cells formed perivascular cells within the frontonasal mesenchyme, and expressed a perivascular marker on the olfactory nerve. Hence, constitutively activating Notch1 is sufficient in vivo to drive not only somite cells, but also neural crest-derived frontonasal mesenchyme and perhaps developing OECs, to a perivascular cell fate. These results also highlight the plasticity of neural crest-derived mesenchyme and glia.

  14. Perivascular neurotransmitters

    DEFF Research Database (Denmark)

    Frederiksen, Simona D; Haanes, Kristian A; Warfvinge, Karin


    disorders. Moreover, neuronal hyperexcitability and other abnormalities have been observed in primary headaches and related to changes in hemodynamic factors. In particular, this relates to migraine aura and spreading depression. During headache attacks, ganglia such as trigeminal and sphenopalatine...... (genetic and environmental influence) with pathophysiological neurovascular alterations. Identified candidate headache genes are associated with neuro- and gliogenesis, vascular development and diseases, and regulation of vascular tone. These findings support a role for the vasculature in primary headache...

  15. Isolation and characterization of canine perivascular stem/stromal cells for bone tissue engineering (United States)

    Hardy, Winters R.; Liang, Pei; Meyers, Carolyn A.; Lobo, Sonja; Lagishetty, Venu; Childers, Martin K.; Asatrian, Greg; Ding, Catherine; Yen, Yu-Hsin; Zou, Erin; Ting, Kang; Peault, Bruno; Soo, Chia


    For over 15 years, human subcutaneous adipose tissue has been recognized as a rich source of tissue resident mesenchymal stem/stromal cells (MSC). The isolation of perivascular progenitor cells from human adipose tissue by a cell sorting strategy was first published in 2008. Since this time, the interest in using pericytes and related perivascular stem/stromal cell (PSC) populations for tissue engineering has significantly increased. Here, we describe a set of experiments identifying, isolating and characterizing PSC from canine tissue (N = 12 canine adipose tissue samples). Results showed that the same antibodies used for human PSC identification and isolation are cross-reactive with canine tissue (CD45, CD146, CD34). Like their human correlate, canine PSC demonstrate characteristics of MSC including cell surface marker expression, colony forming unit-fibroblast (CFU-F) inclusion, and osteogenic differentiation potential. As well, canine PSC respond to osteoinductive signals in a similar fashion as do human PSC, such as the secreted differentiation factor NEL-Like Molecule-1 (NELL-1). Nevertheless, important differences exist between human and canine PSC, including differences in baseline osteogenic potential. In summary, canine PSC represent a multipotent mesenchymogenic cell source for future translational efforts in tissue engineering. PMID:28489940

  16. Isolation and characterization of canine perivascular stem/stromal cells for bone tissue engineering.

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    Aaron W James

    Full Text Available For over 15 years, human subcutaneous adipose tissue has been recognized as a rich source of tissue resident mesenchymal stem/stromal cells (MSC. The isolation of perivascular progenitor cells from human adipose tissue by a cell sorting strategy was first published in 2008. Since this time, the interest in using pericytes and related perivascular stem/stromal cell (PSC populations for tissue engineering has significantly increased. Here, we describe a set of experiments identifying, isolating and characterizing PSC from canine tissue (N = 12 canine adipose tissue samples. Results showed that the same antibodies used for human PSC identification and isolation are cross-reactive with canine tissue (CD45, CD146, CD34. Like their human correlate, canine PSC demonstrate characteristics of MSC including cell surface marker expression, colony forming unit-fibroblast (CFU-F inclusion, and osteogenic differentiation potential. As well, canine PSC respond to osteoinductive signals in a similar fashion as do human PSC, such as the secreted differentiation factor NEL-Like Molecule-1 (NELL-1. Nevertheless, important differences exist between human and canine PSC, including differences in baseline osteogenic potential. In summary, canine PSC represent a multipotent mesenchymogenic cell source for future translational efforts in tissue engineering.

  17. Hippocampal perivascular spaces are related to aging and blood pressure but not to cognition. (United States)

    Yao, Ming; Zhu, Yi-Cheng; Soumaré, Aïcha; Dufouil, Carole; Mazoyer, Bernard; Tzourio, Christophe; Chabriat, Hugues


    The risk factors of hippocampal dilated perivascular spaces (H-dPVS), their radiological relevance and their impact on cognitive performance remain under investigation. These aspects were evaluated in 1818 stroke- and dementia-free participants enrolled in the 3C-Dijon MRI study, using logistic regression, multiple linear regression, and Cox models. At study entry, the load of H-dPVS was found strongly associated with age and hypertension (degree 2 vs. degree 0: odds ratio: 1.16; 95% confidence interval: 1.02-1.33 and odds ratio: 1.98; 95% confidence interval: 1.39-2.81, respectively) and positively related to the presence of lacunar infarcts, white-matter hyperintensities volume, and hippocampal volume (p ≤ 0.024). Load of H-dPVS was not related to baseline cognitive performance (p > 0.05). Cox regression modeling did not show a significant relationship between the load of H-dPVS and incident dementia risk (p > 0.05). The present results support that both aging and blood pressure do play a key role in the development of H-dPVS in the older population. In contrast with the dilated perivascular spaces located in white matter or basal ganglia, the load of H-dPVS does not appear associated with occurrence of dementia. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Linear sign in cystic brain lesions ≥5 mm: A suggestive feature of perivascular space. (United States)

    Sung, Jinkyeong; Jang, Jinhee; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-Soo


    To determine the prevalence of a linear sign within enlarged perivascular space (EPVS) and chronic lacunar infarction (CLI) ≥ 5 mm on T2-weighted imaging (T2WI) and time-of-flight (TOF) magnetic resonance angiography (MRA), and to evaluate the diagnostic value of the linear signs for EPVS over CLI. This study included 101 patients with cystic lesions ≥ 5 mm on brain MRI including TOF MRA. After classification of cystic lesions into EPVS or CLI, two readers assessed linear signs on T2WI and TOF MRA. We compared the prevalence and the diagnostic performance of linear signs. Among 46 EPVS and 51 CLI, 84 lesions (86.6%) were in basal ganglia. The prevalence of T2 and TOF linear signs was significantly higher in the EPVS than in the CLI (P linear signs showed high sensitivity (> 80%). TOF linear sign showed significantly higher specificity (100%) and accuracy (92.8% and 90.7%) than T2 linear sign (P linear signs were more frequently observed in EPVS than CLI. They showed high sensitivity in differentiation of them, especially for basal ganglia. TOF sign showed higher specificity and accuracy than T2 sign. • Linear sign is a suggestive feature of EPVS. • Time-of-flight magnetic resonance angiography can reveal the lenticulostriate artery within perivascular spaces. • Linear sign helps differentiation of EPVS and CLI, especially in basal ganglia.

  19. Perivascular Mast Cells Govern Shear Stress-Induced Arteriogenesis by Orchestrating Leukocyte Function

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    Omary Chillo


    Full Text Available The body has the capacity to compensate for an occluded artery by creating a natural bypass upon increased fluid shear stress. How this mechanical force is translated into collateral artery growth (arteriogenesis is unresolved. We show that extravasation of neutrophils mediated by the platelet receptor GPIbα and uPA results in Nox2-derived reactive oxygen radicals, which activate perivascular mast cells. These c-kit+/CXCR-4+ cells stimulate arteriogenesis by recruiting additional neutrophils as well as growth-promoting monocytes and T cells. Additionally, mast cells may directly contribute to vascular remodeling and vascular cell proliferation through increased MMP activity and by supplying growth-promoting factors. Boosting mast cell recruitment and activation effectively promotes arteriogenesis, thereby protecting tissue from severe ischemic damage. We thus find that perivascular mast cells are central regulators of shear stress-induced arteriogenesis by orchestrating leukocyte function and growth factor/cytokine release, thus providing a therapeutic target for treatment of vascular occlusive diseases.

  20. CD4+ and Perivascular Foxp3+ T Cells in Glioma Correlate with Angiogenesis and Tumor Progression

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    Luyan Mu


    Full Text Available BackgroundAngiogenesis and immune cell infiltration are key features of gliomas and their manipulation of the microenvironment, but their prognostic significance remains indeterminate. We evaluate the interconnection between tumor-infiltrating lymphocyte (TIL and tumor blood-vasculatures in the context of glioma progression.MethodsPaired tumor tissues of 44 patients from three tumor-recurrent groups: diffuse astrocytomas (DA recurred as DA, DA recurred as glioblastomas (GBM, and GBM recurred as GBM were evaluated by genetic analysis, immunohistochemistry for tumor blood vessel density, TIL subsets, and clinical outcomes. These cells were geographically divided into perivascular and intratumoral TILs. Associations were examined between these TILs, CD34+ tumor blood vessels, and clinical outcomes. To determine key changes in TIL subsets, microarray data of 15-paired tumors from patients who failed antiangiogenic therapy- bevacizumab, and 16-paired tumors from chemo-naïve recurrent GBM were also evaluated and compared.ResultsUpon recurrence in primary gliomas, similar kinetic changes were found between tumor blood vessels and each TIL subset in all groups, but only CD4+ including Foxp3+ TILs, positively correlated with the density of tumor blood vessels. CD4 was the predominant T cell population based on the expression of gene-transcripts in primary GBMs, and increased activated CD4+ T cells were revealed in Bevacizumab-resistant recurrent tumors (not in chemo-naïve recurrent tumors. Among these TILs, 2/3 of them were found in the perivascular niche; Foxp3+ T cells in these niches not only correlated with the tumor vessels but were also an independent predictor of shortened recurrence-free survival (RFS (HR = 4.199, 95% CI 1.522–11.584, p = 0.006.ConclusionThe minimal intratumoral T cell infiltration and low detection of CD8 transcripts expression in primary GBMs can potentially limit antitumor response. CD4+ and perivascular Foxp3

  1. Post-radiation fibrosarcoma of the cerebrum associated with a prominent, lace-like, perivascular, desmoplastic change. (United States)

    Shintaku, Masayuki; Adachi, Yasushi; Takeuchi, Yasuhide; Yamamoto, Daisuke; Koyama, Junji


    An intra-axial tumor measuring about 4 cm was excised from the right temporal lobe of a 35-year-old woman, who had a past history of resection of craniopharyngioma and postoperative radiation 21 years earlier. The tumor involved both the cortex and white matter, but was not attached to the dura mater. It consisted of a dense, interlacing, fascicular proliferation of atypical fibroblastic cells and was associated with an extensive, lace-like, desmoplastic change mainly involving the perivascular region around the tumor and overlying the subarachnoid space. The histopathological features of the desmoplastic change resembled meningioangiomatosis, but no proliferation of meningothelial cells was noted. The patient has been free from recurrence for 12 months since the operation. The association of primary cerebral fibrosarcoma with an extensive, lace-like, perivascular, desmoplastic change has not been documented in the literature. The radiation administered 21 years previously may have played some pathogenetic role in the perivascular desmoplastic change, and a malignant transformation of fibroblasts within the perivascular collagenous tissue is considered the most likely origin of the fibrosarcoma. © 2015 Japanese Society of Neuropathology.

  2. Perivascular fibrosis and IgG4-related disease: a case report

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    S. Monti


    Full Text Available Immunoglobulin G4-related disease (IgG4-RD is a newly recognized fibroinflammatory condition which can potentially involve any organ. Some characteristic histopathologic features with lymphoplasmacytic infiltrate, an increased number of IgG4+ cells, storiform fibrosis and obliterative phlebitis are the mainstay for diagnosis. Serum IgG4 levels often increase. We report the case of a patient with perivascular fibrotic lesions involving the aortic arch and the splenic hilum, with a surgical biopsy-proven diagnosis of IgG4-related disease. The patient is now undergoing a low-dose corticosteroid maintenance therapy without evidence of new localizations of the disease. This case highlights the need for increasing awareness and recognition of this new, emerging clinical condition.

  3. Perivascular Epithelioid Cell Tumour with Intraorbital Location: Report of a Case and Review of the Literature

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    Idania Lubo


    Full Text Available The Perivascular Epithelioid Cell tumours (PEComas are rare mesenchymal neoplasms recognized as entity by the World Health Organization. The tumour cells have an uncertain origin and are characterized by distinctive histological and immunohistochemical features. We report a case of PEComa occurring as intraorbital lesion in a 47-year-old man. We found only two other cases described in the literature and we considered all three cases together in order of histology, immunohistochemistry, and clinical outcome. We found a strict histological overlapping and quite similar immunohistological results. All three cases showed a favourable clinical course probably related to small size of tumours (<5 cm, low mitotic rate (<2 mitoses in 50 HPF, and absence of necrosis.

  4. CD133 identifies perivascular niches in grade II-IV astrocytomas

    DEFF Research Database (Denmark)

    Christensen, Karina; Schrøder, Henrik; Kristensen, Bjarne


    The aim of the present study was to investigate the localization and distribution of the putative brain tumour stem cell marker CD133 in formalin fixed paraffin embedded astrocytomas. A retrospective analysis of 114 grade II, III and IV astrocytomas was undertaken. The immunohistochemical...... volume fraction of CD133(+) niches and all CD133(+) tumour cells and tumour grade. However, the volume fraction of CD133(+) blood vessels increased significantly from 0.4% in diffuse astrocytomas to 2.2% in glioblastomas. Neither of them was related to patient survival. Double immunofluorescence...... stainings showed that the CD133(+) niches both contained CD133(+) cells with and without co-expression of the intermediate filament protein marker nestin, and only few CD133(+)/MIB-1(+) proliferating cells were found. In conclusion, a CD133(+) perivascular stem cell-like entity exists in astrocytomas. CD133...

  5. Hoarseness of voice after supraclavicular ultrasound-guided subclavian perivascular brachial plexus block

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    Monika Gupta


    Full Text Available Supraclavicular brachial plexus nerve block is ideal for surgical procedures at or distal to the elbow. Ultrasound (USG continues to grow in popularity as a method of nerve localization, and for the supraclavicular block, it has the advantage of allowing real-time visualization of the plexus, pleura, and vessels along with the needle and local anesthetic spread, but it may conversely create a false sense of security. The incidence of the recurrent laryngeal nerve (RLN block occurring with supraclavicular approach is 1.3% of patients.[10] Incidence of RLN block with USG-guided supraclavicular block is not known. In this case report, we discuss a rare complication of RLN block which occurred while performing a supraclavicular perivascular block performed under USG guidance.

  6. Perivascular epithelioid cell neoplasm of the uterine cervix: an unusual tumor in an unusual location

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    Gary Croghan


    Full Text Available A 46-year-old woman presented for a second opinion regarding a 3-4 cm mass of the uterine cervix. A prior biopsy had been interpreted as a malignant melanoma of the cervix, resulting in a radical hysterectomy with bilateral salpingo-oophorectomy. This was to be followed by external beam irradiation and immunother­apy; however, given the rarity of this diagnosis, the patient sought a second opinion at our institution. Further review of the pathological material from the hysterectomy revealed a morphologically benign perivascular epithelioid cell neoplasm rather than a malignant melanoma. Close monitoring of the patient was recommended; she is currently disease-free more than three years after her initial presentation.

  7. Perivascular epithelioid cell tumor of the liver coexisting with a gastrointestinal stromal tumor

    DEFF Research Database (Denmark)

    Paiva, Carlos Eduardo; Moraes Neto, Francisco Alves; Agaimy, Abbas


    Approximately 10% of patients with gastrointestinal stromal tumors (GIST) develop other neoplasms, either synchronously or metachronously. In this report we describe coexistence of a gastrointestinal stromal tumor and a hepatic perivascular epithelioid cell tumor (PEComa) in a 51-year-old woman...... with no evidence of tuberous sclerosis. A subcapsular hepatic nodule (0.8 cm in diameter) was found during surgery for symptomatic gastric neoplasm (15 cm in diameter) arising from the lesser curvature. Both tumors revealed histomorphological and immunohistochemical features confirming a diagnosis of a small...... incidental hepatic PEComa and a high risky extramural gastric GIST, respectively. The patient remained disease-free 25 mo after surgery with no evidence of tumor recurrence or new neoplasms. To our knowledge, this is the first report of PEComa in a patient with GIST. Hepatic lesions detected synchronously...

  8. Persistent urticaria characterized by recurrent lasting urticarial erythema with histological features of prominent perivascular eosinophilic infiltration. (United States)

    Amano, H; Nagai, Y; Ishikawa, O


    We report a 29-year-old woman with a 15-year history of recurrent pruritic urticarial erythemas. The individual lesions lasted for > 24 h, and antihistaminic agents were not effective. Histological examination of a skin biopsy revealed interstitial oedema of the dermis and perivascular infiltration of numerous eosinophils without vasculitis. No internal organ involvement or peripheral blood eosinophilia was present. A diagnosis of persistent urticaria was made and the patient was successfully treated with oral corticosteroid therapy. Persistent urticaria has been described as an unusual reaction that lasts longer than typical urticaria. It is effectively treated with corticosteroids, but not with antihistaminic agents. In order to choose the most effective treatment, persistent urticaria should be recognized as a different clinical condition from typical urticaria.

  9. Cortical astrogliosis and increased perivascular aquaporin-4 in idiopathic intracranial hypertension. (United States)

    Eide, Per Kristian; Eidsvaag, Vigdis Andersen; Nagelhus, Erlend A; Hansson, Hans-Arne


    The syndrome idiopathic intracranial hypertension (IIH) includes symptoms and signs of raised intracranial pressure (ICP) and impaired vision, usually in overweight persons. The pathogenesis is unknown. In the present prospective observational study, we characterized the histopathological changes in biopsies from the frontal brain cortical parenchyma obtained from 18 IIH patients. Reference specimens were sampled from 13 patients who underwent brain surgery for epilepsy, tumors or acute vascular diseases. Overnight ICP monitoring revealed abnormal intracranial pressure wave amplitudes in 14/18 IIH patients, who underwent shunt surgery and all responded favorably. A remarkable histopathological observation in IIH patients was patchy astrogliosis defined as clusters of hypertrophic astrocytes enclosing a nest of nerve cells. Distinct astrocyte domains (i.e. no overlap between astrocyte processes) were lacking in most IIH biopsy specimens, in contrast to their prevalence in reference specimens. Evidence of astrogliosis in IIH was accompanied with significantly increased aquaporin-4 (AQP4) immunoreactivity over perivascular astrocytic endfeet, compared to the reference specimens, measured with densitometry. Scattered CD68 immunoreactive cells (activated microglia and macrophages) were recognized, indicative of some inflammation. No apoptotic cells were demonstrable. We conclude that the patchy astrogliosis is a major finding in patients with IIH. We propose that the astrogliosis impairs intracranial pressure-volume reserve capacity, i.e. intracranial compliance, and contributes to the IIH by restricting the outflow of fluid from the cranium. The increased perivascular AQP4 in IIH may represent a compensatory mechanism to enhance brain fluid drainage. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Distribution of rSlo Ca2+-activated K+ channels in rat astrocyte perivascular endfeet. (United States)

    Price, Diana L; Ludwig, Jeffrey W; Mi, Huaiyu; Schwarz, Thomas L; Ellisman, Mark H


    Evidence that Ca(2+)-activated K(+) (K(Ca)) channels play a role in cell volume changes and K(+) homeostasis led to a prediction that astrocytes would have K(Ca) channels near blood vessels in order to maintain K(+) homeostasis. Consistent with this thinking the present study demonstrates that rSlo K(Ca) channels are in glial cells of the adult rat central nervous system (CNS) and highly localized to specializations of astrocytes associated with the brain vasculature. Using confocal and thin-section electron microscopic immunolabeling methods the distribution of rSlo was examined in adult rat brain. Strong rSlo immunolabeling was present around the vasculature of most brain regions. Examination of dye-filled hippocampal astrocytes revealed rSlo immunolabeling polarized in astrocytic endfeet. Ultrastructural analysis confirmed that the rSlo staining was concentrated in astrocytic endfeet ensheathing capillaries as well as abutting the pia mater. Immunostaining within the endfeet was predominantly distributed at the plasma membrane directly adjacent to either the vascular basal lamina or the pial surface. The distribution of the aquaporin-4 (AQP-4) water channel was also examined using dye-filled hippocampal astrocytes. In confirmation of earlier reports, intense AQP-4 immunolabeling was generally observed at the perimeter of blood vessels, and coincided with perivascular endfeet and rSlo labeling. We propose that rSlo K(Ca) channels, with their sensitivity to membrane depolarization and intracellular calcium, play a role in the K(+) modulation of cerebral blood flow. Additional knowledge of the molecular and cellular machinery present at perivascular endfeet may provide insight into the structural and functional molecular elements responsible for the neuronal activity-dependent regulation of cerebral blood flow. Copyright 2002 Elsevier Science B.V.

  11. New actions of an old friend: perivascular adipose tissue's adrenergic mechanisms. (United States)

    Ayala-Lopez, Nadia; Watts, Stephanie W


    The revolutionary discovery in 1991 by Soltis and Cassis that perivascular adipose tissue (PVAT) has an anti-contractile effect changed how we think about the vasculature. Most experiments on vascular pharmacology begin by removing the fat surrounding vessels. Thus, PVAT was thought to have a minor role in vascular function and its presence was just for structural support. The need to rethink PVAT's role was precipitated by observations that obesity carries a high cardiovascular risk and PVAT dysfunction is associated with obesity. PVAT is a vascular-adipose organ that has intimate connections with the nervous and immune system. A complex world of physiology resides in PVAT, including the presence of an 'adrenergic system' that is able to release, take up and metabolize noradrenaline. Adipocytes, stromal vascular cells and nerves within PVAT contain components that make up this adrenergic system. Some of the great strides in PVAT research came from studying adipose tissue as a whole. Adipose tissue has many roles and participates in regulating energy balance, energy stores, inflammation and thermoregulation. However, PVAT is dissimilar from non-PVAT adipose tissues. PVAT is intimately connected with the vasculature, which is what makes its role in body homeostasis unique. The adrenergic system within PVAT may be an integral link connecting the effects of obesity with the vascular dysfunction observed in obesity-associated hypertension, a condition in which the sympathetic nervous system has a significant role. This review will explore what is known about the adrenergic system in adipose tissue and PVAT, plus the translational importance of these findings. This article is part of a themed section on Molecular Mechanisms Regulating Perivascular Adipose Tissue - Potential Pharmacological Targets? To view the other articles in this section visit © 2016 The British Pharmacological Society.

  12. Perivascular adipose tissue-secreted angiopoietin-like protein 2 (Angptl2) accelerates neointimal hyperplasia after endovascular injury. (United States)

    Tian, Zhe; Miyata, Keishi; Tazume, Hirokazu; Sakaguchi, Hisashi; Kadomatsu, Tsuyoshi; Horio, Eiji; Takahashi, Otowa; Komohara, Yoshihiro; Araki, Kimi; Hirata, Yoichiro; Tabata, Minoru; Takanashi, Shuichiro; Takeya, Motohiro; Hao, Hiroyuki; Shimabukuro, Michio; Sata, Masataka; Kawasuji, Michio; Oike, Yuichi


    Much attention is currently focused on the role of perivascular adipose tissue in development of cardiovascular disease (CVD). Some researchers view it as promoting CVD through secretion of cytokines and growth factors called adipokines, while recent reports reveal that perivascular adipose tissue can exert a protective effect on CVD development. Furthermore, adiponectin, an anti-inflammatory adipokine, reportedly suppresses neointimal hyperplasia after endovascular injury, whereas such vascular remodeling is enhanced by pro-inflammatory adipokines secreted by perivascular adipose, such as tumor necrosis factor-α (TNF-α). These findings suggest that extent of vascular remodeling, a pathological process associated with CVD development, depends on the balance between pro- and anti-inflammatory adipokines secreted from perivascular adipose tissue. We previously demonstrated that angiopoietin-like protein 2 (Angptl2), a pro-inflammatory factor secreted by adipose tissue, promotes adipose tissue inflammation and subsequent systemic insulin resistance in obesity. Here, we examined whether Angptl2 secreted by perivascular adipose tissue contributes to vascular remodeling after endovascular injury in studies of transgenic mice expressing Angptl2 in adipose tissue (aP2-Angptl2 transgenic mice) and Angptl2 knockout mice (Angptl2(-/-) mice). To assess the role of Angptl2 secreted by perivascular adipose tissue on vascular remodeling after endovascular injury, we performed adipose tissue transplantation experiments using these mice. Wild-type mice with perivascular adipose tissue derived from aP2-Angptl2 mice exhibited accelerated neointimal hyperplasia after endovascular injury compared to wild-type mice transplanted with wild-type tissue. Conversely, vascular inflammation and neointimal hyperplasia after endovascular injury were significantly attenuated in wild-type mice transplanted with Angptl2(-/-) mouse-derived perivascular adipose tissue compared to wild-type mice

  13. Perivascular expression and potent vasoconstrictor effect of dynorphin A in cerebral arteries.

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    Éva Ruisanchez

    Full Text Available BACKGROUND: Numerous literary data indicate that dynorphin A (DYN-A has a significant impact on cerebral circulation, especially under pathophysiological conditions, but its potential direct influence on the tone of cerebral vessels is obscure. The aim of the present study was threefold: 1 to clarify if DYN-A is present in cerebral vessels, 2 to determine if it exerts any direct effect on cerebrovascular tone, and if so, 3 to analyze the role of κ-opiate receptors in mediating the effect. METHODOLOGY/PRINCIPAL FINDINGS: Immunohistochemical analysis revealed the expression of DYN-A in perivascular nerves of rat pial arteries as well as in both rat and human intraparenchymal vessels of the cerebral cortex. In isolated rat basilar and middle cerebral arteries (BAs and MCAs DYN-A (1-13 and DYN-A (1-17 but not DYN-A (1-8 or dynorphin B (DYN-B induced strong vasoconstriction in micromolar concentrations. The maximal effects, compared to a reference contraction induced by 124 mM K(+, were 115±6% and 104±10% in BAs and 113±3% and 125±9% in MCAs for 10 µM of DYN-A (1-13 and DYN-A (1-17, respectively. The vasoconstrictor effects of DYN-A (1-13 could be inhibited but not abolished by both the κ-opiate receptor antagonist nor-Binaltorphimine dihydrochloride (NORBI and blockade of G(i/o-protein mediated signaling by pertussis toxin. Finally, des-Tyr(1 DYN-A (2-13, which reportedly fails to activate κ-opiate receptors, induced vasoconstriction of 45±11% in BAs and 50±5% in MCAs at 10 µM, which effects were resistant to NORBI. CONCLUSION/SIGNIFICANCE: DYN-A is present in rat and human cerebral perivascular nerves and induces sustained contraction of rat cerebral arteries. This vasoconstrictor effect is only partly mediated by κ-opiate receptors and heterotrimeric G(i/o-proteins. To our knowledge our present findings are the first to indicate that DYN-A has a direct cerebral vasoconstrictor effect and that a dynorphin-induced vascular action may be

  14. Perivascular Stem Cells at the Tip of Mouse Incisors Regulate Tissue Regeneration. (United States)

    Pang, Yvonne Wy; Feng, Jifan; Daltoe, Felipe; Fatscher, Robert; Gentleman, Eileen; Gentleman, Molly M; Sharpe, Paul T


    Cells with in vitro properties similar to those of bone marrow stromal stem cells are present in tooth pulp as quiescent cells that are mobilized by damage. These dental pulp stem cells (DPSCs) respond to damage by stimulating proliferation and differentiation into odontoblast-like cells that form dentine to repair the damage. In continuously growing mouse incisors, tissue at the incisor tips is continuously being damaged by the shearing action between the upper and lower teeth acting to self-sharpen the tips. We investigated mouse incisor tips as a model for the role of DPSCs in a continuous natural repair/regeneration process. We show that the pulp at the incisor tip is composed of a disorganized mass of mineralized tissue produced by odontoblast-like cells. These cells become embedded into the mineralized tissue that is rapidly formed and then lost during feeding. Tetracycline labeling not only revealed the expected incorporation into newly synthesized dentine formation of the incisor but also a zone covering the pulp cavity at the tips of the incisors that is mineralized very rapidly. This tissue was dentine-like but had a significantly lower mineral content than dentine as determined by Raman spectroscopy. The mineral was more crystalline than dentine, indicative of small, defect-free mineral particles. To identify the origin of cells responsible for deposition of this mineralized tissue, we genetically labeled perivascular cells by crossing NG2(ERT2) Cre and Nestin Cre mice with reporter mice. A large number of pericyte-derived cells were visible in the pulp of incisor tips with some having elongated, odontoblast-like shapes. These results show that in mouse incisors, rapid, continuous mineralization occurs at the tip to seal off the pulp tissue from the external environment. The mineral is formed by perivascular-derived cells that differentiate into cells expressing dentin sialo-phosphoprotein (DSPP) and produce a dentine-like material in a process that

  15. Blood-neural barrier: its diversity and coordinated cell-to-cell communication. (United States)

    Choi, Yoon Kyung; Kim, Kyu-Won


    The cerebral microvessels possess barrier characteristics which are tightly sealed excluding many toxic substances and protecting neural tissues. The specialized blood-neural barriers as well as the cerebral microvascular barrier are recognized in the retina, inner ear, spinal cord, and cerebrospinal fluid. Microvascular endothelial cells in the brain closely interact with other components such as astrocytes, pericytes, perivascular microglia and neurons to form functional 'neurovascular unit'. Communication between endothelial cells and other surrounding cells enhances the barrier functions, consequently resulting in maintenance and elaboration of proper brain homeostasis. Furthermore, the disruption of the neurovascular unit is closely involved in cerebrovascular disorders. In this review, we focus on the location and function of these various blood-neural barriers, and the importance of the cell-to-cell communication for development and maintenance of the barrier integrity at the neurovascular unit. We also demonstrate the close relation between the alteration of the blood-neural barriers and cerebrovascular disorders.

  16. Differential Diagnosis of the pancreatic disease : significance of perivascular changes at celiac trunk and superior mesenteric artery on CT

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Ryang; Kim, Ki Whang; Yu, Jeong Sik; Kim, Ji Hyung; Kim, Dong Guk; Lee, Sung Il; Ahn, Chang Soo; Oh, Sei Jung [Yonsei Univ., Seoul (Korea, Republic of). Coll. of Medicine; Kim, Young Hwan [Sanggye Paik Hospital, Seoul (Korea, Republic of)


    The purpose of this paper is to classify perivascular change in the celiac trunk and SMA occurring in pancreatic disease and to evaluate its significance in differential diagnosis. In 73 patients with pancreatic disease (42, acute pancreatitis; 14, chronic pancreatitis; 17, pancreatic cancer) abdominal CT findings were retrospectively reviewed. We defined infiltration as linear or irregular density and thickening as presence of a soft tissue mantle surrounding the vessel, and statistically evaluated the usefulness of these factors for the differential diagnosis of pancreatic diseases. Thickening of the celiac trunk and SMA is a valuable finding in the differential diagnosis of pancreatic inflammatory disease and pancreatic cancer. When applied to the differential diagnosis of pancreatic disease, perivascular change should be classified as either infiltration or thickening. (author). 10 refs., 1 tab., 2 figs.

  17. Perivascular Epithelioid Cell Tumor (PEComa of the Uterine Cervix in a Patient with Tuberous Sclerosis Complex: A Literature Review

    Directory of Open Access Journals (Sweden)

    Handan ÇELİK


    Full Text Available Perivascular epithelioid cell tumors (PEComa are a rare type of mesenchymal tumor arising from perivascular epithelial cells. These tumor cells are a co-expression of both melanocytic and myogenic antigens, such as HMB 45 and smooth muscle actin, and at least in some patients, are located around vessels. PEComas has been reported at various sites, including visceral organs, soft tissue, the prostate gland and broad ligaments. In the female reproductive system, the uterine corpus is the most common site of involvement. Some cases are related to tuberous sclerosis complex. Cervical PEComa with tuberous sclerosis complex is presented in the case of a 41 year-old and the literature is reviewed. There have been only eight cases of cervical PEComas and only one other case associated with tuberous sclerosis complex reported to date.

  18. Local Production of Fatty Acid–Binding Protein 4 in Epicardial/Perivascular Fat and Macrophages Is Linked to Coronary Atherosclerosis

    National Research Council Canada - National Science Library

    Furuhashi, Masato; Fuseya, Takahiro; Murata, Masaki; Hoshina, Kyoko; Ishimura, Shutaro; Mita, Tomohiro; Watanabe, Yuki; Omori, Akina; Matsumoto, Megumi; Sugaya, Takeshi; Oikawa, Tsuyoshi; Nishida, Junichi; Kokubu, Nobuaki; Tanaka, Marenao; Moniwa, Norihito; Yoshida, Hideaki; Sawada, Norimasa; Shimamoto, Kazuaki; Miura, Tetsuji


    .... APPROACH AND RESULTS—First, by immunohistochemical analyses, we found that FABP4 was expressed in macrophages within coronary atherosclerotic plaques and epicardial/perivascular fat in autopsy cases and macrophages within...

  19. MMP-Independent Role of TIMP-1 at the Blood Brain Barrier during Viral Encephalomyelitis

    Directory of Open Access Journals (Sweden)

    Carine Savarin


    Full Text Available Infection of the CNS (central nervous system with a sublethal neurotropic coronavirus (JHMV induces a vigorous inflammatory response. CD4+ and CD8+ T cells are essential to control infectious virus but at the cost of tissue damage. An enigma in understanding the contribution of T cell subsets in pathogenesis resides in their distinct migration pattern across the BBB (blood brain barrier. CD4+ T cells transiently accumulate within the perivascular space, whereas CD8+ T cells migrate directly into the CNS parenchyma. As MMPs (matrix metalloproteinases facilitate migration across the glia limitans, specific expression of the TIMP (tissue inhibitor of MMPs-1 by CD4+ T cells present in the perivascular cuffs suggested that TIMP-1 is responsible for stalling CD4+ T cell migration into the CNS parenchyma. Using TIMP-1 deficient mice, the present data demonstrate an increase rather than a decrease in CD4+ T cell accumulation within the perivascular space during JHMV infection. Whereas virus control was not affected by perivascular retention of CD4+ T cells, disease severity was decreased and associated with reduced IFN γ (interferon γ production. Moreover, decreased CD4+ T cell recruitment into the CNS parenchyma of TIMP-1 deficient mice was not associated with impaired T cell recruiting chemokines or MMP expression, and no compensation by other TIMP molecules was identified. These data suggest an MMP-independent role of TIMP-1 in regulating CD4+ T cell access into the CNS parenchyma during acute JHMV encephalitis.

  20. Endothelial function and gene expression in perivascular adipose tissue from internal mammary arteries of obese patients with coronary artery disease. (United States)

    Cybularz, Maria; Langbein, Heike; Zatschler, Birgit; Brunssen, Coy; Deussen, Andreas; Matschke, Klaus; Morawietz, Henning


    Obesity is a risk factor for endothelial dysfunction and atherosclerosis. However, perivascular adipose tissue can release adipokines and other unknown adipose-derived relaxing factors. Therefore, we investigated the impact of obesity on vascular function and expression of genes in perivascular adipose tissue from internal mammary arteries of patients with coronary artery disease undergoing coronary artery bypass grafting. The vessel function was compared between groups of patients with a body-mass index (BMI) between 25 and 30 kg/m 2 . The groups did not differ in age, gender (males), and ejection fraction. Vascular segments of internal mammary arteries were examined in a Mulvany myograph. Following preconstriction with noradrenaline, dose-response curves were assessed for relaxation with acetylcholine and sodium nitroprusside. Maximum contraction in response to potassium and noradrenaline was increased in obese patients with a BMI >30 kg/m 2 . EC50 of endothelium-dependent relaxation was impaired in patients with a BMI above 25, but below 30 kg/m 2 . Sodium nitroprusside-mediated maximal relaxation was not different between study groups. Integrin alpha X chain (ITGAX/CD11c) and macrophage mannose receptor (MRC1/CD206) expression was reduced in perivascular adipose tissue of patients with a BMI above 30 kg/m 2 , while adiponectin (ADPQ) expression was increased in the same tissue. Our data suggest a partially reduced endothelial function in internal mammary arteries of adipose patients with a BMI between 25 and 30 kg/m 2 undergoing coronary artery bypass grafting surgery. Increased adiponectin expression in perivascular tissue might contribute to maintenance of endothelial function in obese patients with a BMI above 30 kg/m 2 . Copyright © 2017 Elsevier B.V. All rights reserved.

  1. CD44 Interacts with HIF-2α to Modulate the Hypoxic Phenotype of Perinecrotic and Perivascular Glioma Cells

    DEFF Research Database (Denmark)

    Johansson, Elinn; Grassi, Elisa S.; Pantazopoulou, Vasiliki


    correlated with CD44. The CD44ICD was sufficient to induce hypoxic signaling at perivascular oxygen tensions, and blocking CD44 cleavage decreased HIF-2α stabilization in CD44-expressing cells. Our data indicate that the stem cell marker CD44 modulates the hypoxic response of glioma cells and that the pseudo......-hypoxic phenotype of stem-like glioma cells is achieved by stabilization of HIF-2α through interaction with CD44, independently of oxygen....

  2. Direct contact with perivascular tumor cells enhances integrin αvβ3 signaling and migration of endothelial cells


    Burgett, M E; Lathia, J D; Roth, P.; Nowacki, A S; Galileo, D S; Pugacheva, E.; Huang, P.; Vasanji, A.; Li, M.; Byzova, T; Mikkelsen, T; Bao, S.; Rich, J N; Weller, M.; Gladson, C. L.


    The secretion of soluble pro-angiogenic factors by tumor cells and stromal cells in the perivascular niche promotes the aggressive angiogenesis that is typical of glioblastoma (GBM). Here, we show that angiogenesis also can be promoted by a direct interaction between brain tumor cells, including tumor cells with cancer stem-like properties (CSCs), and endothelial cells (ECs). As shown in vitro, this direct interaction is mediated by binding of integrin ?v?3 expressed on ECs to the RGD-peptide...

  3. Perivascular adipose tissue, inflammation and insulin resistance: link to vascular dysfunction and cardiovascular disease. (United States)

    Lastra, Guido; Manrique, Camila


    Obesity is a leading risk factor for the development of type 2 diabetes mellitus (DM2) and cardiovascular disease (CVD), however the underlying mechanisms still remain to be fully uncovered. It is now well accepted that dysfunctional adipose tissue in conditions of obesity is a critical source of inflammation that impacts the cardiovascular system and contributes to CVD. Although traditionally visceral adipose tissue has been linked to increased CVD risk, there is mounting interest in the role that fat accumulation around the vasculature plays in the pathogenesis of vascular dysfunction. Perivascular adipose tissue (PVAT) is in intimate contact with large, medium and small diameter arterial beds in several tissues, and has been shown to control vascular function as well as remodeling. PVAT does not merely mirror visceral adipose tissue changes seen in obesity, but has unique features that impact vascular biology. In lean individuals PVAT exerts vasodilatory and anti-inflammatory functions, however obesity results in PVAT inflammation, characterized by imbalance between pro- and anti-inflammatory cells as wells as adipokines. PVAT inflammation promotes insulin resistance in the vasculature, thus resulting in impaired insulin-mediated vasodilatory responses and vascular remodeling. In this review we address current knowledge about the mechanisms that link PVAT inflammation to insulin resistance and vascular dysfunction. Indeed, PVAT emerges as a novel type of adipose tissue that participates in the pathogenesis of CVD, independently to a large extent to visceral adipose tissue.

  4. Linear sign in cystic brain lesions ≥5 mm. A suggestive feature of perivascular space

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Jinkyeong [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of); The Catholic University of Korea, Department of Radiology, St. Vincent' s Hospital, College of Medicine, Seoul (Korea, Republic of); Jang, Jinhee; Choi, Hyun Seok; Jung, So-Lyung; Ahn, Kook-Jin; Kim, Bum-soo [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, College of Medicine, Seoul (Korea, Republic of)


    To determine the prevalence of a linear sign within enlarged perivascular space (EPVS) and chronic lacunar infarction (CLI) ≥ 5 mm on T2-weighted imaging (T2WI) and time-of-flight (TOF) magnetic resonance angiography (MRA), and to evaluate the diagnostic value of the linear signs for EPVS over CLI. This study included 101 patients with cystic lesions ≥ 5 mm on brain MRI including TOF MRA. After classification of cystic lesions into EPVS or CLI, two readers assessed linear signs on T2WI and TOF MRA. We compared the prevalence and the diagnostic performance of linear signs. Among 46 EPVS and 51 CLI, 84 lesions (86.6%) were in basal ganglia. The prevalence of T2 and TOF linear signs was significantly higher in the EPVS than in the CLI (P <.001). For the diagnosis of EPVS, T2 and TOF linear signs showed high sensitivity (> 80%). TOF linear sign showed significantly higher specificity (100%) and accuracy (92.8% and 90.7%) than T2 linear sign (P <.001). T2 and TOF linear signs were more frequently observed in EPVS than CLI. They showed high sensitivity in differentiation of them, especially for basal ganglia. TOF sign showed higher specificity and accuracy than T2 sign. (orig.)

  5. Chronic Lymphocytic Inflammation with Pontine Perivascular Enhancement Responsive to Steroids, with Cranial and Caudal Extension

    Directory of Open Access Journals (Sweden)

    Mahmood Mubasher


    Full Text Available A 23-year-old lady presented with vertigo and imbalance in walking, blurring of vision, diplopia, and headache, in addition to numbness in the lower limbs over a period of six days. On examination patient had nystagmus, ataxia, positive Romberg test, and hyperreflexia. MRI examination of the brain and spinal cord showed evidence of faint bright signal intensity foci in T2/FLAIR involving bilateral cerebral hemispheres, subcortical deep white matter, bilateral thalami, posterior pons and left brachium pontis, and basal ganglia, with small nodular enhancement that aligned along curvilinear structures; those lesions also were apparent along the spinal cord at multiple levels. The clinical and radiological features suggested CLIPPERS (chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids syndrome. Symptoms improved dramatically with high dose oral corticosteroids. Our report addresses the radiological and clinical pattern of a case of CLIPPERS rhombencephalitis, with added superior and inferior extension to involve the brain and spinal cord, which is to emphasize the importance of raising the awareness of this disease and the combined role of radiologist and physicians for the diagnosis of this potentially treatable entity, responsive to glucocorticosteroid immunosuppression.

  6. Loss of anti-contractile effect of perivascular adipose tissue in offspring of obese rats. (United States)

    Zaborska, K E; Wareing, M; Edwards, G; Austin, C


    Maternal obesity pre-programmes offspring to develop obesity and associated cardiovascular disease. Perivascular adipose tissue (PVAT) exerts an anti-contractile effect on the vasculature, which is reduced in hypertension and obesity. The objective of this study was to determine whether maternal obesity pre-programmes offspring to develop PVAT dysfunction in later life. Female Sprague-Dawley rats were fed a diet containing 10% (control) or 45% fat (high fat diet, HFD) for 12 weeks prior to mating and during pregnancy and lactation. Male offspring were killed at 12 or 24 weeks of age and tension in PVAT-intact or -denuded mesenteric artery segments was measured isometrically. Concentration-response curves were constructed to U46619 and norepinephrine. Only 24-week-old HFD offspring were hypertensive (Peffect of PVAT was lost in vessels from HFD offspring of each age. Inhibition of nitric oxide (NO) synthase with 100 μM l-NMMA attenuated the anti-contractile effect of PVAT and increased contractility of PVAT-denuded arteries (Peffect of PVAT was evident only in norepinephrine-contracted vessels. Activation of AMP-activated kinase (with 10 μM A769662) was anti-contractile in PVAT-denuded (Peffect was similar in HFD offspring vessels (Peffects of PVAT in offspring of HFD dams are primarily due to release of a PVAT-derived contractile factor and reduced NO bioavailability.

  7. Relationship between intracranial internal carotid artery calcification and enlarged cerebral perivascular space

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Xiao-Xiao [Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Neurology, Shanghai (China); The First People' s Hospital of Wenling, Department of Neurology, Wenling (China); Li, Ge-Fei; Wu, Yi-Lan; Liu, Yi-Sheng; Zhao, Ying; Shi, Yan-Hui; Zhuang, Mei-Ting; Hou, Tian-Yu; Zhao, Rong; Liu, Feng-Di; Wang, Xue-Mei; Shen, Ying; Cui, Guo-Hong; Su, Jing-Jing; Chen, Wei [Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Neurology, Shanghai (China); Tang, Xue-Mei; Sun, Ji; Liu, Jian-Ren [Shanghai Ninth People' s Hospital, Shanghai Jiao Tong University School of Medicine, Department of Neurology, Shanghai (China); Shanghai Jiao Tong University School of Medicine, Clinical Research Center, Shanghai (China)


    The association between intracranial internal carotid artery (IICA) calcification and lacunes, white matter hyperintensity (WMH), and cerebral microbleeds (CMBs) has been well researched. However, enlarged cerebral perivascular space (PVS) has not yet been reported to correlate with intracranial internal carotid artery calcification. Therefore, the primary aim of this study was to investigate the relationship between IICA calcification and enlarged PVS. A total of 189 patients with ischemic stroke in the middle cerebral artery territory who presented within 7 days of ictus from 2012 to 2015 were enrolled respectively. All patients were required to have undergone head computed tomography, magnetic resonance imaging, susceptibility-weighted magnetic resonance imaging, magnetic resonance angiography, or computed tomography angiography. Clinical characteristics were recorded. IICA calcification and enlarged PVS were semi-quantitatively evaluated, and the presence of lacunes, WMH, and CMBs was recorded. Of the 189 patients, 63.5% were male. Mean age of the patients was 68.6 ± 12.2 years. There were 104 patients with IICA calcification. Age, diabetes mellitus, lacunes, and white matter hyperintensity were significantly associated with IICA calcification (P < 0.05). Multivariate logistic regression analysis showed that age, diabetes mellitus, and lacunes were independent predictors of IICA calcification (P < 0.05). A lower risk of IICA calcification was found in patients with a higher enlarged PVS score (P = 0.004). Higher enlarged PVS scores were associated with a lesser degree of IICA calcification. There appears to be a relationship between reduced risk of IICA calcification and enlarged PVS. (orig.)

  8. The Role of Perivascular Adipose Tissue in Non-atherosclerotic Vascular Disease

    Directory of Open Access Journals (Sweden)

    Tetsuo Horimatsu


    Full Text Available Perivascular adipose tissue (PVAT surrounds most large blood vessels and plays an important role in vascular homeostasis. PVAT releases various chemokines and adipocytokines, functioning in an endocrine and paracrine manner to regulate vascular signaling and inflammation. Mounting evidence suggests that PVAT plays an important role in atherosclerosis and hypertension; however, the role of PVAT in non-atherosclerotic vascular diseases, including neointimal formation, aortic aneurysm, arterial stiffness and vasculitis, has received far less attention. Increasing evidence suggests that PVAT responds to mechanical endovascular injury and regulates the subsequent formation of neointima via factors that promote smooth muscle cell growth, adventitial inflammation and neovascularization. Circumstantial evidence also links PVAT to the pathogenesis of aortic aneurysms and vasculitic syndromes, such as Takayasu's arteritis, where infiltration and migration of inflammatory cells from PVAT into the vascular wall may play a contributory role. Moreover, in obesity, PVAT has been implicated to promote stiffness of elastic arteries via the production of reactive oxygen species. This review will discuss the growing body of data and mechanisms linking PVAT to the pathogenesis of non-atherosclerotic vascular diseases in experimental animal models and in humans.

  9. Hematopoietic stem cell arrival triggers dynamic remodeling of the perivascular niche. (United States)

    Tamplin, Owen J; Durand, Ellen M; Carr, Logan A; Childs, Sarah J; Hagedorn, Elliott J; Li, Pulin; Yzaguirre, Amanda D; Speck, Nancy A; Zon, Leonard I


    Hematopoietic stem and progenitor cells (HSPCs) can reconstitute and sustain the entire blood system. We generated a highly specific transgenic reporter of HSPCs in zebrafish. This allowed us to perform high-resolution live imaging on endogenous HSPCs not currently possible in mammalian bone marrow. Using this system, we have uncovered distinct interactions between single HSPCs and their niche. When an HSPC arrives in the perivascular niche, a group of endothelial cells remodel to form a surrounding pocket. This structure appears conserved in mouse fetal liver. Correlative light and electron microscopy revealed that endothelial cells surround a single HSPC attached to a single mesenchymal stromal cell. Live imaging showed that mesenchymal stromal cells anchor HSPCs and orient their divisions. A chemical genetic screen found that the compound lycorine promotes HSPC-niche interactions during development and ultimately expands the stem cell pool into adulthood. Our studies provide evidence for dynamic niche interactions upon stem cell colonization. PAPERFLICK: Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Impact of fibroblast growth factor 21 on the secretome of human perivascular preadipocytes and adipocytes: a targeted proteomics approach. (United States)

    Berti, Lucia; Hartwig, Sonja; Irmler, Martin; Rädle, Bernhard; Siegel-Axel, Dorothea; Beckers, Johannes; Lehr, Stefan; Al-Hasani, Hadi; Häring, Hans-Ulrich; Hrabě de Angelis, Martin; Staiger, Harald


    Perivascular adipose tissue (PVAT) is suggested to impact on vascular cells via humoral factors, possibly contributing to endothelial dysfunction and atherosclerosis. To address whether the hepatokine fibroblast growth factor (FGF) 21 affects the PVAT secretome. Human perivascular (pre)adipocytes were subjected to targeted proteomics and whole-genome gene expression analysis. Preadipocytes, as compared to adipocytes, secreted higher amounts of inflammatory cytokines and chemokines. Adipocytes released higher amounts of adipokines [e.g. adipisin, visfatin, dipeptidyl peptidase 4 (DPP4), leptin; p < 0.05, all]. In preadipocytes, omentin 1 release was 1.28-fold increased by FGF-21 (p < 0.05). In adipocytes, FGF-21 reduced chemerin release by 5% and enhanced DPP4 release by 1.15-fold (p < 0.05, both). FGF-21 altered the expression of four secretory genes in preadipocytes and of 18 in adipocytes (p < 0.01, all). The hepatokine FGF-21 exerts secretome-modulating effects in human perivascular (pre)adipocytes establishing a new liver-PVAT-blood vessel axis that possibly contributes to vascular inflammation and atherosclerosis.

  11. Direct Leukocyte Migration across Pulmonary Arterioles and Venules into the Perivascular Interstitium of Murine Lungs during Bleomycin Injury and Repair (United States)

    Wang, Ping M.; Kachel, Diane L.; Cesta, Mark F.; Martin, William J.


    During acute lung injury and repair, leukocytes are thought to enter the lung primarily across alveolar capillaries and postcapillary venules. We hypothesized that leukocytes also migrate across pulmonary arterioles and venules, which serve as alternative sites for leukocyte influx into the lung during acute lung injury and repair. Lung sections from C57BL/6J mice up to 14 days after intratracheal bleomycin (3.33 U/kg) or saline instillation were assessed by light, fluorescence, confocal, and transmission electron microscopy for evidence of inflammatory cell sequestration and transmigration at these sites. After bleomycin treatment, large numbers of leukocytes (including neutrophils, eosinophils, and monocytes) were present in the vascular lumina and in perivascular interstitia of pulmonary arterioles and venules, as well as within the vascular walls. Leukocytes were observed within well-defined pathways in arteriolar walls and much less structured pathways in venular walls, apparently in the process of transmigration. Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were expressed at sites of leukocyte interaction with the luminal surface, especially in arterioles. Leukocytes appeared to exit from the vessels near collagen fibers into the perivascular interstitium. Results indicate that leukocytes can directly migrate across arteriolar and venular walls into the perivascular interstitium, which may represent an important but under-recognized pathway for leukocyte influx into the lung during injury and repair. PMID:21641381

  12. Mechanisms of Glioma Formation: Iterative Perivascular Glioma Growth and Invasion Leads to Tumor Progression, VEGF-Independent Vascularization, and Resistance to Antiangiogenic Therapy

    Directory of Open Access Journals (Sweden)

    Gregory J. Baker


    Full Text Available As glioma cells infiltrate the brain they become associated with various microanatomic brain structures such as blood vessels, white matter tracts, and brain parenchyma. How these distinct invasion patterns coordinate tumor growth and influence clinical outcomes remain poorly understood. We have investigated how perivascular growth affects glioma growth patterning and response to antiangiogenic therapy within the highly vascularized brain. Orthotopically implanted rodent and human glioma cells are shown to commonly invade and proliferate within brain perivascular space. This form of brain tumor growth and invasion is also shown to characterize de novo generated endogenous mouse brain tumors, biopsies of primary human glioblastoma (GBM, and peripheral cancer metastasis to the human brain. Perivascularly invading brain tumors become vascularized by normal brain microvessels as individual glioma cells use perivascular space as a conduit for tumor invasion. Agent-based computational modeling recapitulated biological perivascular glioma growth without the need for neoangiogenesis. We tested the requirement for neoangiogenesis in perivascular glioma by treating animals with angiogenesis inhibitors bevacizumab and DC101. These inhibitors induced the expected vessel normalization, yet failed to reduce tumor growth or improve survival of mice bearing orthotopic or endogenous gliomas while exacerbating brain tumor invasion. Our results provide compelling experimental evidence in support of the recently described failure of clinically used antiangiogenics to extend the overall survival of human GBM patients.

  13. Building barriers. (United States)

    Turksen, Kursad


    Formation of tissue barriers starts in early development where it is critical for normal cell fate selection, differentiation and organogenesis. Barrier maintenance is critical to the ongoing function of organs during adulthood and aging. Dysfunctional tissue barrier formation and function at any stage of the organismal life cycle underlies many disease states.

  14. Perivascular Mesenchymal Stem Cells From the Adult Human Brain Harbor No Instrinsic Neuroectodermal but High Mesodermal Differentiation Potential. (United States)

    Lojewski, Xenia; Srimasorn, Sumitra; Rauh, Juliane; Francke, Silvan; Wobus, Manja; Taylor, Verdon; Araúzo-Bravo, Marcos J; Hallmeyer-Elgner, Susanne; Kirsch, Matthias; Schwarz, Sigrid; Schwarz, Johannes; Storch, Alexander; Hermann, Andreas


    Brain perivascular cells have recently been identified as a novel mesodermal cell type in the human brain. These cells reside in the perivascular niche and were shown to have mesodermal and, to a lesser extent, tissue-specific differentiation potential. Mesenchymal stem cells (MSCs) are widely proposed for use in cell therapy in many neurological disorders; therefore, it is of importance to better understand the "intrinsic" MSC population of the human brain. We systematically characterized adult human brain-derived pericytes during in vitro expansion and differentiation and compared these cells with fetal and adult human brain-derived neural stem cells (NSCs) and adult human bone marrow-derived MSCs. We found that adult human brain pericytes, which can be isolated from the hippocampus and from subcortical white matter, are-in contrast to adult human NSCs-easily expandable in monolayer cultures and show many similarities to human bone marrow-derived MSCs both regarding both surface marker expression and after whole transcriptome profile. Human brain pericytes showed a negligible propensity for neuroectodermal differentiation under various differentiation conditions but efficiently generated mesodermal progeny. Consequently, human brain pericytes resemble bone marrow-derived MSCs and might be very interesting for possible autologous and endogenous stem cell-based treatment strategies and cell therapeutic approaches for treating neurological diseases. Perivascular mesenchymal stem cells (MSCs) recently gained significant interest because of their appearance in many tissues including the human brain. MSCs were often reported as being beneficial after transplantation in the central nervous system in different neurological diseases; therefore, adult brain perivascular cells derived from human neural tissue were systematically characterized concerning neural stem cell and MSC marker expression, transcriptomics, and mesodermal and inherent neuroectodermal differentiation

  15. Dilated perivascular spaces and fatigue: is there a link? Magnetic resonance retrospective 3Tesla study

    Energy Technology Data Exchange (ETDEWEB)

    Conforti, Renata; Cirillo, Mario; Sardaro, Angela; Negro, Alberto; Cirillo, Sossio [Second University of Naples, Neuroradiology Service, Department of Radiology, Naples (Italy); Caiazzo, Giuseppina; Paccone, Antonella [Second University of Naples, MRI Research Center SUN-FISM, Naples (Italy); Sacco, Rosaria; Sparaco, Maddalena; Gallo, Antonio; Lavorgna, Luigi; Tedeschi, Gioacchino [Second University of Naples, Department of Neurology, Naples (Italy)


    Fatigue (F) is a common, inexplicable, and disabling symptom in multiple sclerosis (MS) patients. The purpose of this study was to evaluate a possible correlation between fatigue and morpho-volumetric features and site of dilated perivascular spaces (dPS), visible on 3T magnetic resonance (MR) in fatigued multiple sclerosis patients (FMS). We studied 82 relapsing remitting (RR) FMS patients and 43 HC, matched for age, sex, and education. F was assessed by the Fatigue Severity Scale (FSS). To evaluate a possible correlation between degree of F and characteristics of dPS, patients were divided in two groups: more (mFMS) (FSS ≥ 5; n = 30) and less fatigued (lFMS) (FSS ≥ 4; n = 52), compared to a matched healthy control (HC) subject group. The MR study was performed with 3T scanner by SpinEcho T1, Fast-SpinEcho DP-T2, FLAIR, and 3D FSPGR T1 sequences. dPS volumes were measured with Medical Image Processing Analysis and Visualization (MIPAV); Global Cerebral Atrophy (GCA), expressed as Brain Parenchymal Fraction (BPF), was assessed by FSL SIENAX. The t test showed significantly increased dPS number (p = 0.021) in FMS patients (mFMS p = 0.0024 and lFMS p = 0.033) compared to HC. Pearson correlation revealed a significant correlation between dPS number and FSS (r = 0.208 p = 0.051). Furthermore, the chi-squared test confirms the intragroup (HC, mFMS, lFMS) differences about dPS location (p = 0.01) and size (p = 0.0001). Our study confirms that PS in MS patients presents with different volumetric and site characteristics as compared to HC; moreover, F severity significantly correlates with dPS number, site, and size. (orig.)

  16. Quantification of perivascular spaces at 7T: A potential MRI biomarker for epilepsy. (United States)

    Feldman, Rebecca Emily; Rutland, John Watson; Fields, Madeline Cara; Marcuse, Lara Vanessa; Pawha, Puneet S; Delman, Bradley Neil; Balchandani, Priti


    7T (7T) magnetic resonance imaging (MRI) facilitates the visualization of the brain with resolution and contrast beyond what is available at conventional clinical field strengths, enabling improved detection and quantification of small structural features such as perivascular spaces (PVSs). The distribution of PVSs, detected in vivo at 7T, may act as a biomarker for the effects of epilepsy. In this work, we systematically quantify the PVSs in the brains of epilepsy patients and compare them to healthy controls. T2-weighted turbo spin echo images were obtained at 7T on 21 epilepsy patients and 17 healthy controls. For all subjects, PVSs were manually marked on Osirix image analysis software. Marked PVSs with diameter≥0.5mm were then mapped by hemisphere and lobe. The asymmetry index (AI) was calculated for each region and the maximum asymmetry index (|AImax|) was reported for each subject. The asymmetry in epilepsy subjects was compared to that of controls, and the region with highest asymmetry was compared to the suspected seizure onset zone. There was a significant difference between the |AImax| in epilepsy subjects and in controls (p=0.016). In 72% of patients, the region or lobe of the brain showing maximum PVS asymmetry was the same as the region containing the suspected seizure onset zone. These findings suggest that epilepsy may be associated with significantly asymmetric distribution of PVSs in the brain. Furthermore, the region of maximal asymmetry of the PVSs may help provide localization or confirmation of the seizure onset zone. Copyright © 2017 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.

  17. Endothelial and Perivascular Adipose Tissue Abnormalities in Obesity-Related Vascular Dysfunction: Novel Targets for Treatment. (United States)

    Schinzari, Francesca; Tesauro, Manfredi; Cardillo, Carmine


    The heavy impact of obesity on the development and progression of cardiovascular disease has sparked sustained efforts to uncover the mechanisms linking excess adiposity to vascular dysfunction. In addition to its well-established role in maintaining vascular homeostasis, the endothelium has been increasingly recognized as a key player in modulating healthy adipose tissue expansion in response to excess calories by providing adipocyte precursors and driving angiogenesis. When this increased storage need is unmet, excessive deposition of fat occurs at ectopic locations, including perivascular adipose tissue (PVAT). PVAT is in intimate contact with the vessel wall, hence affecting vascular function and structure. In lean individuals, PVAT exerts anticontractile and anti-inflammatory activities to protect the vasculature. In obesity, instead, these beneficial properties are lost and PVAT releases inflammatory mediators, promotes oxidative stress, and contributes to vascular dysfunction. The underlying mechanisms elicited by these outside-in signals include resistance to the vasodilator actions of insulin and activation of endothelin (ET)-1-mediated vasoconstriction. A number of adipokines and gut hormones, which are important modulators of food intake, energy balance, glucose and lipid metabolism, insulin sensitivity, and inflammation, have also positive vascular actions. This feature makes them promising tools for targeting both the metabolic and cardiovascular complications of obesity, a view supported by recent large-scale clinical trials indicating that novel drugs for type 2 diabetes with cardiovascular potential may translate into clinically significant benefits. There is, therefore, real hope that unleashing the power of fat- and gut-derived substances might provide effective dual-action therapies for obesity and its complications.

  18. Methotrexate improves perivascular adipose tissue/endothelial dysfunction via activation of AMPK/eNOS pathway. (United States)

    Ma, Yanmin; Li, Li; Shao, Yating; Bai, Xiaohong; Bai, Tiao; Huang, Xinliang


    Adipose and endothelial dysfunction is associated with cardiovascular disease. Perivascular adipose tissue (PVAT) directly surrounds vessels and influences vessel function via a paracrine effect, and adenosine monophosphate (AMP)-activated protein kinase (AMPK) modulates the metabolic pathway, thus, the present study hypothesized that activation of AMPK in PVAT may regulate endothelial function in pathological settings. The present study investigated the effect of methotrexate (MTX) on adipocytokine expression in PVAT with an emphasis on the regulation of endothelial function. The effects of MTX and the mechanisms involved were investigated using a relaxation assay and western blot analysis. Reverse transcription‑quantitative polymerase chain reaction and western blotting were used to detect the mRNA and protein expression levels. ELISA assay was used to quantify the level of TNF‑α and IL‑6. Palmitic acid (PA) stimulation induced inflammation and dysregulation of adipocytokine expression in PVAT. MTX treatment inhibited nuclear factor‑κB p65 phosphorylation and downregulated expression of pro‑inflammatory cytokines, including tumor necrosis factor‑α and interleukin-6, whereas adiponectin expression increased. MTX increased AMPK phosphorylation under basal and inflammatory conditions in PVAT, whereas knockdown of AMPK via small interfering RNA diminished its modulatory effect, indicating that MTX inhibits inflammation in an AMPK‑dependent manner. The present study prepared conditioned medium from PA‑stimulated PVAT to induce endothelial dysfunction and observed that pre‑treatment of PVAT with MTX effectively restored the loss of acetylcholine‑induced vasodilation and increased endothelial nitric oxide synthase phosphorylation in the rat aorta. The results of the present study demonstrated that MTX ameliorated inflammation-associated adipocytokine dysregulation and thus prevented endothelial dysfunction. These data provide further

  19. Vitamin D Controls Resistance Artery Function through Regulation of Perivascular Adipose Tissue Hypoxia and Inflammation (United States)

    Pelham, Christopher J.; Drews, Elizabeth M.; Agrawal, Devendra K.


    Vitamin D deficiency in human subjects is associated with hypertension, metabolic syndrome and related risk factors of cardiovascular diseases. Serum 25-hydroxyvitamin D levels correlate inversely with adiposity in obese and lean individuals. Bioactive vitamin D, or calcitriol, exerts anti-inflammatory effects on adipocytes, preadipocytes and macrophages in vitro. We tested the hypothesis that vitamin D deficiency alters the phenotype of perivascular adipose tissue (PVAT) leading to impaired function in resistance artery. To examine the effects of vitamin D and PVAT on vascular reactivity, myograph experiments were performed on arteries, with or without intact PVAT, from mice maintained on vitamin D-deficient, vitamin D-sufficient or vitamin D-supplemented diet. Systolic blood pressure was significantly increased in mice on vitamin D-deficient diet. Importantly, vitamin D deficiency enhanced angiotensin II-induced vasoconstriction and impaired the normal ability of PVAT to suppress contractile responses of the underlying mesenteric resistance artery to angiotensin II and serotonin. Furthermore, vitamin D deficiency caused upregulation of the mRNA expression of tumor necrosis factor-α, hypoxia-inducible factor-1α and its downstream target lysyl oxidase in mesenteric PVAT. Incubation of mesenteric arteries under hypoxic conditions impaired the anti-contractile effects of intact PVAT on those arteries from mice on vitamin D-sufficient diet. Vitamin D supplementation protected arteries against hypoxia-induced impairment of PVAT function. The protective effects of vitamin D against vascular dysfunction, hypertension and cardiovascular diseases may be mediated, at least in part, through regulation of inflammatory and hypoxia signaling pathways in PVAT. PMID:27374117

  20. Brain Atrophy Correlates with Severe Enlarged Perivascular Spaces in Basal Ganglia among Lacunar Stroke Patients.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Zhang

    Full Text Available Enlarged perivascular spaces (EPVS correlate with cognitive impairment and incident dementia. However, etiologies for severe basal ganglia EPVS (BG-EPVS are still unclear. Our aim was to investigate the independent risk factors for severe BG-EPVS in patients with acute lacunar stroke.We prospectively identified patients with lacunar stroke (diameter on DWI ≤ 20mm from Jan 2011 to May 2015. Patients with severe BG-EPVS were identified on T2 weighted MRI. Age (± 1 year and sex matched controls were also recruited in the same population (two controls for one case. Vascular risk factors, clinical data, EPVS in centrum semiovale (rated 0 to 4, white matter hyperintensities (WMH (by Fazekas scale, brain atrophy (rated 0 to 6 were compared between two groups. Logistic regression was performed to determine independent risk factors for severe BG-EPVS.During study period, 89 patients with severe BG-EPVS and 178 matched controls were included. Vascular risk factors did not differ between two groups. Patients with severe BG-EPVS had lower level of HbA1c and diastolic BP at admission, but presented with larger infarct size, more severe WMH (including total WMH, periventricular WMH and deep WMH and brain atrophy. In logistic regression, brain atrophy (OR = 1.40; 95%CI 1.13, 1.73 and deep WMH (OR = 1.88; 95%CI 1.24, 2.83 were independent risk factors for severe BG-EPVS.Brain atrophy and deep WMH are independent risk factors for severe BG-EPVS, supporting the hypothesis that brain atrophy may be associated with the development of EPVS in basal ganglia.

  1. The relationship between ambulatory blood pressure variability and enlarged perivascular spaces: a cross-sectional study. (United States)

    Yang, Shuna; Qin, Wei; Yang, Lei; Fan, Huimin; Li, Yue; Yin, Jiangmei; Hu, Wenli


    Recent studies reported that 24-hour ambulatory blood pressure variability (ABPV) was associated with lacunar infarction and white matter hyperintensities (WMH). However, the relationship between ABPV and enlarged perivascular spaces (EPVS) has not been investigated. Thus, our study aimed to investigate whether ABPV is associated with EPVS by 24-hour ambulatory blood pressure monitoring (ABPM). We conducted this study as a cross-sectional study. The study was based on patients who presented for physical examinations in our hospital from May 2013 to June 2016. Patients with both brain MRI scans and 24-hour ABPM were included and patients with acute stroke, a history of severe stroke and some other severe diseases were excluded. A total of 573 Chinese patients were prospectively enrolled in this study. EPVS in basal ganglia (BG) and white matter (WM) were identified on MRI and classified into three categories by the severity. WMH were scored by the Fazekas scale. Coefficient of variation (CV) and SD were considered as metrics of ABPV. Spearman correlation analysis and ordinal logistic regression analysis were used to assess the relationship between ABPV and EPVS. There were statistical differences among the subgroups stratified by the severity of EPVS in BG in the following ABPV metrics: SD and CV of systolic blood pressure (SBP), CV of diastolic blood pressure (DBP) in 24 hours, daytime and nighttime and SD of DBP in nighttime. The above ABPV metrics were positively associated with the degree of EPVS. The association was unchanged after adjusting for confounders. Spearman correlation analysis showed ABPV was not related to the degree of EPVS in the WM. ABPV was independently associated with EPVS in BG after controlling for blood pressure, but not in the WM. Pathogenesis of EPVS in BG and WM might be different. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted

  2. Transcriptional Networks in Single Perivascular Cells Sorted from Human Adipose Tissue Reveal a Hierarchy of Mesenchymal Stem Cells. (United States)

    Hardy, W Reef; Moldovan, Nicanor I; Moldovan, Leni; Livak, Kenneth J; Datta, Krishna; Goswami, Chirayu; Corselli, Mirko; Traktuev, Dmitry O; Murray, Iain R; Péault, Bruno; March, Keith


    Adipose tissue is a rich source of multipotent mesenchymal stem-like cells, located in the perivascular niche. Based on their surface markers, these have been assigned to two main categories: CD31 - /CD45 - /CD34 + /CD146 - cells (adventitial stromal/stem cells [ASCs]) and CD31 - /CD45 - /CD34 - /CD146 + cells (pericytes [PCs]). These populations display heterogeneity of unknown significance. We hypothesized that aldehyde dehydrogenase (ALDH) activity, a functional marker of primitivity, could help to better define ASC and PC subclasses. To this end, the stromal vascular fraction from a human lipoaspirate was simultaneously stained with fluorescent antibodies to CD31, CD45, CD34, and CD146 antigens and the ALDH substrate Aldefluor, then sorted by fluorescence-activated cell sorting. Individual ASCs (n = 67) and PCs (n = 73) selected from the extremities of the ALDH-staining spectrum were transcriptionally profiled by Fluidigm single-cell quantitative polymerase chain reaction for a predefined set (n = 429) of marker genes. To these single-cell data, we applied differential expression and principal component and clustering analysis, as well as an original gene coexpression network reconstruction algorithm. Despite the stochasticity at the single-cell level, covariation of gene expression analysis yielded multiple network connectivity parameters suggesting that these perivascular progenitor cell subclasses possess the following order of maturity: (a) ALDH br ASC (most primitive); (b) ALDH dim ASC; (c) ALDH br PC; (d) ALDH dim PC (least primitive). This order was independently supported by specific combinations of class-specific expressed genes and further confirmed by the analysis of associated signaling pathways. In conclusion, single-cell transcriptional analysis of four populations isolated from fat by surface markers and enzyme activity suggests a developmental hierarchy among perivascular mesenchymal stem cells supported by markers and coexpression

  3. MWA Versus RFA for Perivascular and Peribiliary CRLM: A Retrospective Patient- and Lesion-Based Analysis of Two Historical Cohorts

    Energy Technology Data Exchange (ETDEWEB)

    Tilborg, Aukje A. J. M. van, E-mail:; Scheffer, Hester J.; Jong, Marcus C. de; Vroomen, Laurien G. P. H. [VU University Medical Centre, Department of Radiology and Nuclear Medicine (Netherlands); Nielsen, Karin [VU University Medical Centre, Department of Surgical Oncology (Netherlands); Kuijk, Cornelis van [VU University Medical Centre, Department of Radiology and Nuclear Medicine (Netherlands); Tol, Petrousjka M. P. van den [VU University Medical Centre, Department of Surgical Oncology (Netherlands); Meijerink, Martijn R. [VU University Medical Centre, Department of Radiology and Nuclear Medicine (Netherlands)


    PurposeTo retrospectively analyse the safety and efficacy of radiofrequency ablation (RFA) versus microwave ablation (MWA) in the treatment of unresectable colorectal liver metastases (CRLM) in proximity to large vessels and/or major bile ducts.Method and MaterialsA database search was performed to include patients with unresectable histologically proven and/or {sup 18}F–FDG–PET avid CRLM who were treated with RFA or MWA between January 2001 and September 2014 in a single centre. All lesions that were considered to have a peribiliary and/or perivascular location were included. Univariate logistic regression analysis was performed to assess the distribution of patient, tumour and procedure characteristics. Multivariate logistic regression was used to correct for potential confounders.ResultsTwo hundred and forty-three patients with 774 unresectable CRLM were ablated. One hundred and twenty-two patients (78 males; 44 females) had at least one perivascular or peribiliary lesion (n = 199). Primary efficacy rate of RFA was superior to MWA after 3 and 12 months of follow-up (P = 0.010 and P = 0.022); however, after multivariate analysis this difference was non-significant at 12 months (P = 0.078) and vanished after repeat ablations (P = 0.39). More CTCAE grade III complications occurred after MWA versus RFA (18.8 vs. 7.9 %; P = 0.094); biliary complications were especially common after peribiliary MWA (P = 0.002).ConclusionFor perivascular CRLM, RFA and MWA are both safe treatment options that appear equally effective. For peribiliary CRLM, MWA has a higher complication rate than RFA, with similar efficacy. Based on these results, it is advised to use RFA for lesions in the proximity of major bile ducts.

  4. Subclavian perivascular block for open reduction and internal fixation of left midshaft humeral fracture--a case report. (United States)

    Rukewe, A; Ogunlade, S O; Idowu, O A; Aderinto, D A


    Traumatic injuries affecting bones of the hand and forearm often require peripheral nerve blocks for analgesia and surgical intervention. The successful use of subclavian perivascular block as a sole anaesthetic for orthopaedic surgery has not been reported in our environment. We report the use of this technique for open reduction and internal fixation of a left midshaft humeral fracture. The trunk of the brachial plexus was localized by a Polystim II nerve stimulator. Complete sensorimotor block was achieved within 15 minutes and surgery lasted 55 minutes without complications. This technique obviated the use of general anaesthesia with its risks. The surgeon and the patient were satisfied with the quality of the anaesthesia.

  5. Prevalence of and risk factors for enlarged perivascular spaces in adult patients with moyamoya disease. (United States)

    Kuribara, Tomoyoshi; Mikami, Takeshi; Komatsu, Katsuya; Suzuki, Hime; Ohnishi, Hirofumi; Houkin, Kiyohiro; Mikuni, Nobuhiro


    Enlarged perivascular spaces (EPVS) are often observed with magnetic resonance imaging in patients with small vessel disease. However, the risk factors, radiological features, and clinical relevance of EPVS in patients with moyamoya disease are poorly understood. The purpose of this study was to evaluate EPVS, the risk factors of many EPVS, and the pathophysiology of EPVS in adult patients with moyamoya disease. One hundred cerebral hemispheres of 50 adult patients with moyamoya disease were examined. The control group consisted of 50 age/sex-matched patients without ischemic disease. The numbers of EPVS at the level of the centrum semiovale per hemisphere were compared between the moyamoya disease and control groups. In each hemisphere, the total numbers of EPVS were categorized into five grades (0-4), and the clinical and radiological characteristics of the predictive factors in patients in the high EPVS grade group (EPVS grade = 4) were assessed. The EPVS counts and grades were significantly higher in the moyamoya disease group. Analyses of the background characteristics of the patients with moyamoya disease revealed that significantly higher prevalence of high EPVS grades were associated with the female sex, hypertension, high magnetic resonance angiography scores, high numbers of flow voids in the basal ganglia, high brain atrophy scores, ivy signs, and white matter lesions. A logistic multivariate analysis of the patients with high EPVS grades revealed significant associations with the female sex, hypertension, and flow voids in the basal ganglia. Increased EPVS were confirmed in adult patients with moyamoya disease, and the associated clinical and radiological factors were identified. The presence of hypertension, the female sex, and flow voids in the basal ganglia were important for predicting high EPVS grades in patients with moyamoya disease. Reductions in arterial pulsations with steno-occlusive changes can inhibit the flow of interstitial fluid, which

  6. Col1a1+ perivascular cells in the brain are a source of retinoic acid following stroke. (United States)

    Kelly, Kathleen K; MacPherson, Amber M; Grewal, Himmat; Strnad, Frank; Jones, Jace W; Yu, Jianshi; Pierzchalski, Keely; Kane, Maureen A; Herson, Paco S; Siegenthaler, Julie A


    Perivascular stromal cells (PSCs) are a recently identified cell type that comprises a small percentage of the platelet derived growth factor receptor-β+ cells within the CNS perivascular space. PSCs are activated following injury to the brain or spinal cord, expand in number and contribute to fibrotic scar formation within the injury site. Beyond fibrosis, their high density in the lesion core makes them a potential significant source of signals that act on neural cells adjacent to the lesion site. Our developmental analysis of PSCs, defined by expression of Collagen1a1 in the maturing brain, revealed that PSCs first appear postnatally and may originate from the meninges. PSCs express many of the same markers as meningeal fibroblasts, including expression of the retinoic acid (RA) synthesis proteins Raldh1 and Raldh2. Using a focal brain ischemia injury model to induce PSC activation and expansion, we show a substantial increase in Raldh1+/Raldh2+ PSCs and Raldh1+ activated macrophages in the lesion core. We find that RA levels are significantly elevated in the ischemic hemisphere and induce signaling in astrocytes and neurons in the peri-infarct region. This study highlights a dual role for activated, non-neural cells where PSCs deposit fibrotic ECM proteins and, along with macrophages, act as a potentially important source of RA, a potent signaling molecule that could influence recovery events in a neuroprotective fashion following brain injury.

  7. Induction of Perivascular Neural Stem Cells and Possible Contribution to Neurogenesis Following Transient Brain Ischemia/Reperfusion Injury. (United States)

    Nakata, Masayo; Nakagomi, Takayuki; Maeda, Mitsuyo; Nakano-Doi, Akiko; Momota, Yoshihiro; Matsuyama, Tomohiro


    Recent therapeutic advances have increased the likelihood of recanalizing the obstructed brain arteries in patients with stroke. Therefore, it is important to understand the fate of neural cells under transient ischemia/reperfusion injury. Accumulating evidence shows that neurogenesis occurs in perivascular regions following brain injury, although the precise mechanism and origin of these newborn neurons under transient ischemia/reperfusion injury remain unclear. Using a mouse model of transient brain ischemia/reperfusion injury, we found that neural stem cells (NSCs) develop within injured areas. This induction of NSCs following ischemia/reperfusion injury was observed even in response to nonlethal ischemia, although massive numbers of NSCs were induced by lethal ischemia. Immunohistochemical and immunoelectron microscopic studies indicated that platelet-derived growth factor receptor beta-positive (PDGFRβ+) pericytes within injured areas following nonlethal ischemia began to express the NSC marker nestin as early as 3 days after transient ischemia/reperfusion. Some PDGFRβ+ pericytes expressed the immature neuronal marker doublecortin at day 7. These findings indicate that brain pericytes are a potential source of the perivascular NSCs that generate neuronal cells under lethal and nonlethal ischemic conditions following transient ischemia/reperfusion. Thus, brain pericytes might be a target for neurogenesis mediation in patients with nonlethal and lethal ischemia following transient ischemia/reperfusion injury.

  8. The relaxing effect of perivascular tissue on porcine retinal arterioles in vitro is mimicked by N-methyl-D-aspartate and is blocked by prostaglandin synthesis inhibition

    DEFF Research Database (Denmark)

    Holmgaard, Kim; Aalkjaer, Christian; Lambert, John D C


    -APV, an antagonist at the same receptor), the natural inhibitory transmitter GABA, and picrotoxin (an antagonist at ionotropic GABA receptors). These experiments were made in the absence and presence of the COX inhibitor, ibuprofen. RESULTS: U46619 caused a concentration-dependent contraction of isolated retinal...... arterioles. This vasoconstriction was significantly smaller in the presence of perivascular tissue. The NMDA-receptor antagonist, DL-APV, reduced this attenuating influence of the perivascular tissue on the response to U46619, and the response could be modified by NMDA and GABA, but not by picrotoxin...

  9. Blood-CNS Barrier Impairment in ALS Patients versus an Animal Model

    Directory of Open Access Journals (Sweden)

    Svitlana eGarbuzova-Davis


    Full Text Available Amyotrophic lateral sclerosis (ALS is a severe neurodegenerative disease with a compli-cated and poorly understood pathogenesis. Recently, alterations in the blood-Central Nervous System barrier (B-CNS-B have been recognized as a key factor possibly aggravating motor neuron damage. The majority of findings on ALS microvascular pathology have been deter-mined in mutant SOD1 rodent models, identifying barrier damage during disease develop-ment which might similarly occur in familial ALS patients carrying the SOD1 mutation. However, our knowledge of B-CNS-B competence in sporadic ALS (SALS has been limited. We recently showed structural and functional impairment in postmortem gray and white mat-ter microvessels of medulla and spinal cord tissue from SALS patients, suggesting pervasive barrier damage. Although numerous signs of barrier impairment (endothelial cell degenera-tion, capillary leakage, perivascular edema, downregulation of tight junction proteins, and microhemorrhages are indicated in both mutant SOD1 animal models of ALS and SALS pa-tients, other pathogenic barrier alterations have as yet only been identified in SALS patients. Pericyte degeneration, perivascular collagen IV expansion, and white matter capillary abnor-malities in SALS patients are significant barrier related pathologies yet to be noted in ALS SOD1 animal models. In the current review, these important differences in blood-CNS barrier damage between ALS patients and animal models, which may signify altered barrier transport mechanisms, are discussed. Understanding discrepancies in barrier condition between ALS patients and animal models may be crucial for developing effective therapies.

  10. Markers of fibroblast-rich tumor stroma and perivascular cells in serous ovarian cancer: Inter- and intra-patient heterogeneity and impact on survival. (United States)

    Corvigno, Sara; Wisman, G Bea A; Mezheyeuski, Artur; van der Zee, Ate G J; Nijman, Hans W; Åvall-Lundqvist, Elisabeth; Östman, Arne; Dahlstrand, Hanna


    Inter- and intra-patient variations in tumor microenvironment of serous ovarian cancer are largely unexplored. We aimed to explore potential co-regulation of tumor stroma characteristics, analyze their concordance in primary and metastatic lesions, and study their impact on survival. A tissue microarray (TMA) with 186 tumors and 91 matched metastases was subjected to immunohistochemistry double staining with endothelial cell marker CD34 and fibroblast and pericyte markers α-SMA, PDGFβR and desmin. Images were digitally analyzed to yield "metrics" related to vasculature and stroma features. Intra-case analyses showed that PDGFβR in perivascular cells and fibroblasts were strongly correlated. Similar findings were observed concerning α-SMA. Most stroma characteristics showed large variations in intra-case comparisons of primary tumors and metastasis. Large PDGFβR-positive stroma fraction and high PDGFβFR positive perivascular intensity were both significantly associated with shorter survival in uni- and multi-variate analyses (HR 1.7, 95% CI 1.1-2.5; HR 1.7, 95% CI 1.1-2.8). In conclusion, we found PDGFβR- and α-SMA-expression to be largely independent of each other but concordantly activated in perivascular cells and in fibroblasts within the primary tumor. Stromal characteristics differed between primary tumors and metastases. PDGFβR in perivascular cells and in fibroblasts may be novel prognostic markers in serous ovarian cancer.

  11. Perivascular adipose tissue control of insulin-induced vasoreactivity in muscle is impaired in db/db mice

    DEFF Research Database (Denmark)

    Meijer, Rick I; Bakker, Wineke; Alta, Caro-Lynn A F


    Microvascular recruitment in muscle is a determinant of insulin sensitivity. Whether perivascular adipose tissue (PVAT) is involved in disturbed insulin-induced vasoreactivity is unknown, as are the underlying mechanisms. This study investigates whether PVAT regulates insulin-induced vasodilation...... in muscle, the underlying mechanisms, and how obesity disturbs this vasodilation. Insulin-induced vasoreactivity of resistance arteries was studied with PVAT from C57BL/6 or db/db mice. PVAT weight in muscle was higher in db/db mice compared with C57BL/6 mice. PVAT from C57BL/6 mice uncovered insulin......-induced vasodilation in an adiponectin-dependent manner. In conclusion, PVAT controls insulin-induced vasoreactivity in the muscle microcirculation through secretion of adiponectin and subsequent AMPKa2 signaling. PVAT from obese mice inhibits insulin-induced vasodilation, which can be restored by inhibition of JNK....

  12. Variable involvement of the perivascular retinal tissue in carbonic anhydrase inhibitor induced relaxation of porcine retinal arterioles in vitro

    DEFF Research Database (Denmark)

    Kehler, Anne Katrine; Holmgaard, Kim; Hessellund, Anders


    PURPOSE: Inhibition of carbonic anhydrase in the eye is an important treatment modality for reducing the intraocular pressure in glaucoma. However, evidence suggests that carbonic anhydrase inhibition also exerts a relaxing effect on the vessels in the optic nerve, and it has been suggested...... in a myograph. After precontraction with the prostaglandin analogue U46619, the vasorelaxing effect of the carbonic anhydrase inhibitors methyl bromopyruvate, ethyl bromopyruvate, acetazolamide, and dorzolamide were studied. RESULTS: All the examined carbonic anhydrase inhibitors induced a significant...... relaxation of retinal arterioles. There was no significant difference between the effect of the different carbonic anhydrase inhibitors in the presence of perivascular retinal tissue. However, in the isolated retinal arterioles the vasodilating effect of dorzolamide was significantly lower...

  13. Successful treatment with the mTOR inhibitor everolimus in a patient with Perivascular epithelioid cell tumor

    Directory of Open Access Journals (Sweden)

    Gennatas Constantine


    Full Text Available Abstract Perivascular epithelioid cell tumor (PEComa is an extremely rare neoplasm that appears to arise most commonly at visceral (especially gastrointestinal and uterine, retroperitoneal, and abdominopelvic sites. Malignant PEComas exist but are very rare. These tumors represent a family of mesenchymal neoplasms, mechanistically linked through activation of the mTOR signaling pathway. Metastatic PEComa is a rare form of sarcoma for which no effective therapy has been described previously and that has a uniformly fatal outcome. Although there is no known effective therapy, the molecular pathophysiology of aberrant mTOR signaling provides a scientific rationale to target this pathway therapeutically. The difficulty in determining optimal therapy, owing to the sparse literature available, led us to present this case. On this basis, we report a case of metastatic retroperitoneal PEComa treated with an oral mTOR inhibitor, with everolimus achieving significant clinical response.

  14. Organizational barriers (United States)

    Kenneth S. Blonski


    One of the traditional roles that prescribed fire has played in the fire management arena is reduction of hazardous fuel buildups under controlled, well-defined environmental conditions. However, our ability to use this tool effectively is blocked by many barriers. The preceding panel discussion about the causes of limited success in implementing prescribed burning...

  15. Immune challenge by intraperitoneal administration of lipopolysaccharide directs gene expression in distinct blood-brain barrier cells toward enhanced prostaglandin E(2) signaling. (United States)

    Vasilache, Ana Maria; Qian, Hong; Blomqvist, Anders


    The cells constituting the blood-brain barrier are critical for the transduction of peripheral immune signals to the brain, but hitherto no comprehensive analysis of the signaling events that occur in these cells in response to a peripheral inflammatory stimulus has been performed. Here, we examined the inflammatory transcriptome in blood-brain barrier cells, including endothelial cells, pericytes, and perivascular macrophages, which were isolated by fluorescent-activated cell sorting, from non-immune-challenged mice and from mice stimulated by bacterial wall lipopolysaccharide. We show that endothelial cells and perivascular macrophages display distinct transcription profiles for inflammatory signaling and respond in distinct and often opposing ways to the immune stimulus. Thus, endothelial cells show induced PGE2 synthesis and transport with attenuation of PGE2 catabolism, increased expression of cytokine receptors and down-stream signaling molecules, and downregulation of adhesion molecules. In contrast, perivascular macrophages show downregulation of the synthesis of prostanoids other than PGE2 and of prostaglandin catabolism, but upregulation of interleukin-6 synthesis. Pericytes were largely unresponsive to the immune stimulation, with the exception of downregulation of proteins involved in pericyte-endothelial cell communication. While the endothelial cells account for most of the immune-induced gene expression changes in the blood-brain barrier, the response of the endothelial cells occurs in a concerted manner with that of the perivascular cells to elevate intracerebral levels of PGE2, hence emphasizing the critical role of PGE2 in immune-induced signal transduction across the blood-brain barrier. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Celecoxib, but not indomethacin, ameliorates the hypertensive and perivascular fibrotic actions of cyclosporine in rats: Role of endothelin signaling

    Energy Technology Data Exchange (ETDEWEB)

    El-Mas, Mahmoud M., E-mail: [Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University (Egypt); Helmy, Maged W. [Pharmacology and Toxicology, Faculty of Pharmacy, Damanhour University (Egypt); Ali, Rabab M.; El-Gowelli, Hanan M. [Pharmacology and Toxicology, Faculty of Pharmacy, Alexandria University (Egypt)


    The immunosuppressant drug cyclosporine (CSA) is used with nonsteroidal antiinflammatory drugs (NSAIDs) in arthritic conditions. In this study, we investigated whether NSAIDs modify the deleterious hypertensive action of CSA and the role of endothelin (ET) receptors in this interaction. Pharmacologic, protein expression, and histopathologic studies were performed in rats to investigate the roles of endothelin receptors (ET{sub A}/ET{sub B}) in the hemodynamic interaction between CSA and two NSAIDs, indomethacin and celecoxib. Tail-cuff plethysmography measurements showed that CSA (20 mg kg{sup −1} day{sup −1}, 10 days) increased systolic blood pressure (SBP) and heart rate (HR). CSA hypertension was associated with renal perivascular fibrosis and divergent changes in immunohistochemical signals of renal arteriolar ET{sub A} (increases) and ET{sub B} (decreases) receptors. While these effects of CSA were preserved in rats treated concomitantly with indomethacin (5 mg kg{sup −1} day{sup −1}), celecoxib (10 mg kg{sup −1} day{sup −1}) abolished the pressor, tachycardic, and fibrotic effects of CSA and normalized the altered renal ET{sub A}/ET{sub B} receptor expressions. Selective blockade of ET{sub A} receptors by atrasentan (5 mg kg{sup −1} day{sup −1}) abolished the pressor response elicited by CSA or CSA plus indomethacin. Alternatively, BQ788 (ET{sub B} receptor blocker, 0.1 mg kg{sup −1} day{sup −1}) caused celecoxib-sensitive elevations in SBP and potentiated the pressor response evoked by CSA. Together, the improved renovascular fibrotic and endothelin receptor profile (ET{sub A} downregulation and ET{sub B} upregulation) mediate, at least partly, the protective effect of celecoxib against the hypertensive effect of CSA. Clinically, the use of celecoxib along with CSA in the management of arthritic conditions might provide hypertension-free regimen. - Highlights: • Chronic CSA causes hypertension and renal perivascular fibrosis in rats.

  17. Aging Exacerbates Obesity-Induced Oxidative Stress and Inflammation in Perivascular Adipose Tissue in Mice: A Paracrine Mechanism Contributing to Vascular Redox Dysregulation and Inflammation


    Bailey-Downs, Lora C.; Tucsek, Zsuzsanna; TOTH, Peter; Sosnowska, Danuta; Gautam, Tripti; Sonntag, William E.; Csiszar, Anna; Ungvari, Zoltan


    Obesity in the elderly individuals is increasing at alarming rates and there is evidence suggesting that elderly individuals are more vulnerable to the deleterious cardiovascular effects of obesity than younger individuals. However, the specific mechanisms through which aging and obesity interact to promote the development of cardiovascular disease remain unclear. The present study was designed to test the hypothesis that aging exacerbates obesity-induced inflammation in perivascular adipose ...

  18. Aging exacerbates obesity-induced oxidative stress and inflammation in perivascular adipose tissue in mice: a paracrine mechanism contributing to vascular redox dysregulation and inflammation. (United States)

    Bailey-Downs, Lora C; Tucsek, Zsuzsanna; Toth, Peter; Sosnowska, Danuta; Gautam, Tripti; Sonntag, William E; Csiszar, Anna; Ungvari, Zoltan


    Obesity in the elderly individuals is increasing at alarming rates and there is evidence suggesting that elderly individuals are more vulnerable to the deleterious cardiovascular effects of obesity than younger individuals. However, the specific mechanisms through which aging and obesity interact to promote the development of cardiovascular disease remain unclear. The present study was designed to test the hypothesis that aging exacerbates obesity-induced inflammation in perivascular adipose tissue, which contributes to increased vascular oxidative stress and inflammation in a paracrine manner. To test this hypothesis, we assessed changes in the secretome, reactive oxygen species production, and macrophage infiltration in periaortic adipose tissue of young (7 month old) and aged (24 month old) high-fat diet-fed obese C57BL/6 mice. High-fat diet-induced vascular reactive oxygen species generation significantly increased in aged mice, which was associated with exacerbation of endothelial dysfunction and vascular inflammation. In young animals, high-fat diet-induced obesity promoted oxidative stress in the perivascular adipose tissue, which was associated with a marked proinflammatory shift in the profile of secreted cytokines and chemokines. Aging exacerbated obesity-induced oxidative stress and inflammation and significantly increased macrophage infiltration in periaortic adipose tissue. Using cultured arteries isolated from young control mice, we found that inflammatory factors secreted from the perivascular fat tissue of obese aged mice promote significant prooxidative and proinflammatory phenotypic alterations in the vascular wall, mimicking the aging phenotype. Overall, our findings support an important role for localized perivascular adipose tissue inflammation in exacerbation of vascular oxidative stress and inflammation in aging, an effect that likely enhances the risk for development of cardiovascular diseases from obesity in the elderly individuals.

  19. Human perivascular adipose tissue dysfunction as a cause of vascular disease: Focus on vascular tone and wall remodeling. (United States)

    Ozen, Gulsev; Daci, Armond; Norel, Xavier; Topal, Gokce


    Obesity is one of the major risk factors for the development of cardiovascular diseases. It is characterized by excessive or abnormal accumulation of adipose tissue, including depots which surround the blood vessels named perivascular adipose tissue (PVAT). PVAT plays endocrine and paracrine roles by producing large numbers of metabolically vasoactive adipokines. The present review outlines our current understanding of the beneficial roles of PVAT in vascular tone and remodeling in healthy subjects supported by clinical studies, highlighting different factors or mechanisms that could mediate protective effects of PVAT on vascular function. Most studies in humans show that adiponectin is the best candidate for the advantageous effect of PVAT. However, in pathological conditions especially obesity-related cardiovascular diseases, the beneficial effects of PVAT on vascular functions are impaired and transform into detrimental roles. This change is defined as PVAT dysfunction. In the current review, the contribution of PVAT dysfunction to obesity-related cardiovascular diseases has been discussed with a focus on possible mechanisms including an imbalance between beneficial and detrimental adipokines (commonly described as decreased levels of adiponectin and increased levels of leptin or tumor necrosis factor-alpha (TNFα)), increased quantity of adipose tissue, inflammation, cell proliferation and endothelial dysfunction. Finally, novel pharmacotherapeutic targets for the treatment of cardiovascular and metabolic disorders are addressed. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Perivascular adipose tissue and the dynamic regulation of Kv 7 and Kir channels: Implications to resistant hypertension. (United States)

    Gollasch, Maik; Welsh, Donald G; Schubert, Rudolf


    Resistant hypertension is defined as high blood pressure that remains uncontrolled despite treatment with at least three antihypertensive drugs at adequate doses. Resistant hypertension is an increasingly common clinical problem in older age, obesity, diabetes, sleep apnea, and chronic kidney disease. Although the direct vasodilator minoxidil was introduced in the early 1970s, only recently has this drug been shown to be particularly effective in a subgroup of patients with treatment-resistant or uncontrolled hypertension. This pharmacological approach is interesting from a mechanistic perspective since minoxidil is the only clinically used K+ channel opener today, which targets a subclass of K+ channels, namely KATP channels in vascular smooth muscle cells (VSMCs). Beside KATP channels, two other classes of VSMC K+ channels could represent novel effective targets for treatment of resistant hypertension, namely Kv 7 (KCNQ) and inward rectifier potassium (Kir 2.1) channels. Interestingly, these channels are unique among VSMC potassium channels. First, both have been implicated in the control of microvascular tone by perivascular adipose tissue. Second, they exhibit biophysical properties strongly controlled and regulated by membrane voltage, but not intracellular calcium. This review focuses on Kv 7 (Kv 7.1-5) and Kir (Kir 2.1) channels in VSMCs as potential novel drug targets for treatment of resistant hypertension, particularly in comorbid conditions such as obesity and metabolic syndrome. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  1. Decrease in the numbers of dendritic cells and CD4+ T cells in cerebral perivascular spaces due to natalizumab. (United States)

    del Pilar Martin, Maria; Cravens, Petra D; Winger, Ryan; Frohman, Elliot M; Racke, Michael K; Eagar, Todd N; Zamvil, Scott S; Weber, Martin S; Hemmer, Bernhard; Karandikar, Nitin J; Kleinschmidt-DeMasters, B K; Stüve, Olaf


    To extend our studies on the prolonged and differential effect of natalizumab on T lymphocyte numbers in the cerebrospinal fluid, we investigated the number and phenotypes of leukocytes and the expression of major histocompatibility complex (MHC) classes I and II in cerebral perivascular spaces (CPVS). We hypothesized that natalizumab reduces the number of antigen presenting cells in CPVS. A case-control study in which inflammatory cell numbers in the CPVS of cerebral tissue were assessed by immunohistochemical staining. A patient with multiple sclerosis (MS) who developed progressive multifocal leukoencephalopathy (PML) during natalizumab therapy. Controls included location-matched cerebral autopsy material of patients without disease of the central nervous system, patients with MS not treated with natalizumab, and patients with PML not associated with natalizumab therapy. The absolute number of CPVS in the patient with MS treated with natalizumab was significantly lower than in the control groups owing to extensive destruction of the tissue architecture. The expression of MHC class II molecules and the number of CD209+ dendritic cells were significantly decreased in the CPVS of the patient with MS treated with natalizumab. No CD4+ T cells were detectable. Our observations may explain the differential and prolonged effects of natalizumab therapy on leukocyte numbers in the cerebrospinal fluid.

  2. Clinical Correlates, Ethnic Differences, and Prognostic Implications of Perivascular Spaces in Transient Ischemic Attack and Ischemic Stroke. (United States)

    Lau, Kui-Kai; Li, Linxin; Lovelock, Caroline E; Zamboni, Giovanna; Chan, Tsz-Tai; Chiang, Man-Fung; Lo, Kin-Ting; Küker, Wilhelm; Mak, Henry Ka-Fung; Rothwell, Peter M


    Perivascular spaces (PVSs) are considered markers of small vessel disease. However, their long-term prognostic implications in transient ischemic attack/ischemic stroke patients are unknown. Ethnic differences in PVS prevalence are also unknown. Two independent prospective studies were conducted, 1 comprising predominantly whites with transient ischemic attack/ischemic stroke (OXVASC [Oxford Vascular] study) and 1 comprising predominantly Chinese with ischemic stroke (University of Hong Kong). Clinical and imaging correlates, prognostic implications for stroke and death, and ethnic differences in basal ganglia (BG) and centrum semiovale (CS) PVSs were studied with adjustment for age, sex, vascular risk factors, and scanner strength. Whites with transient ischemic attack/ischemic stroke (n=1028) had a higher prevalence of both BG and CS-PVSs compared with Chinese (n=974; >20 BG-PVSs: 22.4% versus 7.1%; >20 CS-PVSs: 45.8% versus 10.4%; P stroke (adjusted hazard ratio compared with 20 PVSs: HR, 1.82; 1.18-2.80; P =0.011) but not intracerebral hemorrhage ( P =0.10) or all-cause mortality ( P =0.16). CS-PVSs were not associated with recurrent stroke ( P =0.57) or mortality ( P =0.072). Prognostic associations were similar in both cohorts. Over and above ethnic differences in frequency of PVSs in transient ischemic attack/ischemic stroke patients, BG and CS-PVSs had similar risk factors, but although >20 BG-PVSs were associated with an increased risk of recurrent ischemic stroke, CS-PVSs were not. © 2017 The Authors.

  3. Patients experiences of negative pressure wound therapy at home for the treatment of deep perivascular groin infection after vascular surgery. (United States)

    Monsen, Christina; Acosta, Stefan; Kumlien, Christine


    To explore experiences of negative pressure wound therapy at home, in patients with deep perivascular groin infection after vascular surgery and management in daily life. Deep surgical site infection after vascular surgery with exposed vessels often requires long-term treatment with negative pressure wound therapy, and continued therapy at home has become routine. An explorative qualitative study. Nine men and six women with a deep surgical site infection in the groin after vascular surgery, treated in their home with negative pressure wound therapy, were interviewed. The interviews were analysed using manifest and latent content analysis. Undergoing negative pressure wound therapy at home meant a transition from being a dependent patient to a person who must have self-care competence and be involved in their own care. A need to feel prepared for this before discharge from hospital was expressed. Lack of information and feelings of uncertainty prolonged the time before feeling confident in managing the treatment. The informants gradually accepted the need to be tied up to a machine, became competent in its management and found solutions to perform everyday tasks. Overall, it was a relief to be treated at home. Several benefits of negative pressure wound therapy at home were expressed. However, unnecessary stress and anxiety were experienced due to a lack of information on the treatment and instruction concerning the equipment. Adequate information and education must therefore be provided to facilitate the transition from a patient to a person with self-care competence and ability to manage this treatment at home. The findings revealed a need for more support and knowledge in their transition from hospital care to home care with negative pressure wound therapy. Routines must be established that ensure patient safety and security in treatment at home. © 2016 John Wiley & Sons Ltd.


    Zaborska, K; Austin, C; Wareing, M; Edwards, G


    Maternal obesity pre-programmes offspring to develop obesity, glucose intolerance and associated cardiovascular disease later in life although the underlying mechanism is currently unknown. This study investigated the effect of a maternal high fat diet on endothelial and perivascular adipose tissue (PVAT) regulation of resistance artery tone. 8 week old female SD rats were fed a 10% fat diet (controls) or 45% fat obesogenic diet (HFD) for 12 weeks before mating then continued on their respective diets during pregnancy and lactation. PVAT-intact or -denuded mesenteric arteries from dams and pups (250-300 μm internal diameter) were mounted on a wire myograph. Cumulative concentration-response curves were constructed to thromboxane A2 receptor agonist U46619 (10nM-3 μM) ± 10 μM A769662, an activator of AMP-activated kinase (AMPK), and/or 100 μM L-NMMA, a nitric oxide synthase (NOS) inhibitor. Body weight (BW) and systolic (SBP) and diastolic (DBP) blood pressure were significantly increased in HFD dams (BW: p effect in artery segments from control dams and their offspring at 12 and 24 weeks (p effect which was lost in both dams fed HFD and their offspring. AMPK activation decreased contractility of both PVAT-denuded and intact control vessels in the presence and absence of a NOS inhibitor in control dams (p effect was decreased in PVAT-intact vessels of HFD dams and their offspring. In summary, the attenuated anti-contractile effects of PVAT in HFD dams and their offspring may be modulated by AMPK; however it is not totally dependent on nitric oxide release.

  5. A randomised study of NPWT closure versus alginate dressings in peri-vascular groin infections: quality of life, pain and cost. (United States)

    Monsen, C; Acosta, S; Mani, K; Wann-Hansson, C


    The aim of this study was to compare the vacuum assisted wound closure (VAC) system (negative pressure wound therapy; NPWT) and alginate wound dressings in terms of quality of life (QoL), pain resource use and cost in patients with deep peri-vascular groin infection after vascular surgery. Patients with deep peri-vascular groin infection (Szilagyi grade III) were included and randomised to NPWT or alginate therapy. EuroQol 5D (EQ-5D) and brief pain inventory (BPI) were used to evaluate QoL and pain, respectively. Wound healing time until complete skin epithelialisation was shorter in the NPWT (n=9) compared to the alginate group (n=7), median 57 and 104 days, respectively (p=0.026). No difference was recorded in QoL and pain between the groups at study start and the second assessment. QoL analysis within groups between time points, showed that patients in NPWT groups improved in EQ-5D domains, 'self-care' (p= 0.034), 'usual activities' (p=0.046); EQ-5D index value (p=0.046) and EQ-VAS (p=0.028). Patients in the NPWT group reported significantly less pain 'affecting their relations with other people' and 'sleep' between time points. The NPWT group had significantly fewer dressing changes compared to the alginate group (pcost was 83-87% of the total cost in both groups. NPWT therapy in patients with deep peri-vascular groin infection can be regarded as the dominant strategy due to improved clinical outcome with equal cost and quality of life measures.

  6. Ameliorative effect of Eucommia ulmoides Oliv. leaves extract (ELE) on insulin resistance and abnormal perivascular innervation in fructose-drinking rats. (United States)

    Jin, Xin; Amitani, Keisuke; Zamami, Yoshito; Takatori, Shingo; Hobara, Narumi; Kawamura, Naomi; Hirata, Tetsuya; Wada, Atsunori; Kitamura, Yoshihisa; Kawasaki, Hiromu


    Eucommia ulmoides Oliv. leaf is a traditional Chinese medicine that exhibits an anti-diabetic action. This study was designed to investigate whether long-term administration of Eucommia ulmoides Oliv. leaves extract (ELE) ameliorates pre-diabetic state of insulin resistance and abnormal perivascular innervation in the hyperinsulinemic state. ELE at doses of 500 and 1000mg/kg was administered orally once daily for 4 weeks in fructose-drinking rats (FDRs). Plasma levels of insulin, blood glucose levels, and perivascular innervation were assessed using biochemical and immunohistochemical methods. FDR showed significant increase in plasma levels of insulin, an index for insulin resistance (Homeostasis Model Assessment ratio-HOMA-IR) and systolic blood pressure (SBP), but not blood glucose levels, as compared with control rats. Immunohistochemical study showed significantly greater density of tyrosine hydroxylase (TH)-like immunoreactivity (LI)-containing nerves and significantly lower density of calcitonin gene-related peptide (CGRP)-LI-containing nerves in mesenteric arteries of FDR than those in control. A 4-week treatment with ELE (500 and 1000mg/kg, p.o.) significantly decreased plasma levels of insulin and HOMA-IR without affecting blood glucose levels and significantly lowered SBP in FDR. ELE treatment in FDR resulted in significant increase in CGRP-LI never fiber density and significant decrease in TH-LI never fiber density in mesenteric arteries of FDR. These results suggest that long-term ELE treatment effectively prevents insulin resistance development and ameliorates abnormal perivascular innervation in FDR. Copyright 2010 Elsevier Ireland Ltd. All rights reserved.

  7. Proliferating cells in psoriatic dermis are comprised primarily of T cells, endothelial cells, and factor XIIIa+ perivascular dendritic cells

    Energy Technology Data Exchange (ETDEWEB)

    Morganroth, G.S.; Chan, L.S.; Weinstein, G.D.; Voorhees, J.J.; Cooper, K.D. (Univ. of Michigan Medical School, Ann Arbor (USA))


    Determination of the cell types proliferating in the dermis of patients with psoriasis should identify those cells experiencing activation or responding to growth factors in the psoriatic dermal milieu. Toward that end, sections of formalin-fixed biopsies obtained from 3H-deoxyuridine (3H-dU)-injected skin of eight psoriatic patients were immunostained, followed by autoradiography. Proliferating dermal cells exhibit silver grains from tritium emissions. The identity of the proliferating cells could then be determined by simultaneous visualization with antibodies specific for various cell types. UCHL1+ (CD45RO+) T cells (recall antigen-reactive helper T-cell subset) constituted 36.6 +/- 3.1% (mean +/- SEM, n = 6) of the proliferating dermal cells in involved skin, whereas Leu 18+ (CD45RA+) T cells (recall antigen naive T-cell subsets) comprised only 8.7 +/- 1.5% (n = 6). The Factor XIIIa+ dermal perivascular dendritic cell subset (24.9 +/- 1.5% of proliferating dermal cells, n = 6) and Factor VIII+ endothelial cells represented the two other major proliferating populations in lesional psoriatic dermis. Differentiated tissue macrophages, identified by phase microscopy as melanophages or by immunostaining with antibodies to Leu M1 (CD15) or myeloid histiocyte antigen, comprised less than 5% of the proliferating population in either skin type. In addition to calculating the relative proportions of these cells to each other as percent, we also determined the density of cells, in cells/mm2 of tissue. The density of proliferating cells within these populations was increased in involved versus uninvolved skin: UCHL1+, 9.0 +/- 1.7 cells/mm2 versus 1.8 +/- 0.6 cells/mm2, p less than 0.01; Factor XIIIa+, 6.0 +/- 0.7 cells/mm2 versus 1.5 +/- 0.5 cells/mm2, p less than 0.01; Factor VIII+, 5.5 +/- 1.4 cells/mm2 versus 0.0 cells/mm2, p less than 0.05.

  8. Local Production of Fatty Acid-Binding Protein 4 in Epicardial/Perivascular Fat and Macrophages Is Linked to Coronary Atherosclerosis. (United States)

    Furuhashi, Masato; Fuseya, Takahiro; Murata, Masaki; Hoshina, Kyoko; Ishimura, Shutaro; Mita, Tomohiro; Watanabe, Yuki; Omori, Akina; Matsumoto, Megumi; Sugaya, Takeshi; Oikawa, Tsuyoshi; Nishida, Junichi; Kokubu, Nobuaki; Tanaka, Marenao; Moniwa, Norihito; Yoshida, Hideaki; Sawada, Norimasa; Shimamoto, Kazuaki; Miura, Tetsuji


    Fatty acid-binding protein 4 (FABP4) is expressed in adipocytes and macrophages, and elevated circulating FABP4 level is associated with obesity-mediated metabolic phenotype. We systematically investigated roles of FABP4 in the development of coronary artery atherosclerosis. First, by immunohistochemical analyses, we found that FABP4 was expressed in macrophages within coronary atherosclerotic plaques and epicardial/perivascular fat in autopsy cases and macrophages within thrombi covering ruptured coronary plaques in thrombectomy samples from patients with acute myocardial infarction. Second, we confirmed that FABP4 was secreted from macrophages and adipocytes cultured in vitro. Third, we investigated the effect of exogenous FABP4 on macrophages and human coronary artery-derived smooth muscle cells and endothelial cells in vitro. Treatment of the cells with recombinant FABP4 significantly increased gene expression of inflammatory markers in a dose-dependent manner. Finally, we measured serum FABP4 level in the aortic root (Ao-FABP4) and coronary sinus (CS-FABP4) of 34 patients with suspected or known coronary artery disease. Coronary stenosis score assessed by the modified Gensini score was weakly correlated with CS-FABP4 but was not correlated with Ao-FABP4. A stronger correlation (r=0.59, Pepicardial/perivascular fat and macrophages in vascular plaques contributes to the development of coronary atherosclerosis. © 2016 American Heart Association, Inc.

  9. Smart parking barrier

    KAUST Repository

    Alharbi, Abdulrazaq M.


    Various methods and systems are provided for smart parking barriers. In one example, among others, a smart parking barrier system includes a movable parking barrier located at one end of a parking space, a barrier drive configured to control positioning of the movable parking barrier, and a parking controller configured to initiate movement of the parking barrier, via the barrier drive. The movable parking barrier can be positioned between a first position that restricts access to the parking space and a second position that allows access to the parking space. The parking controller can initiate movement of the movable parking barrier in response to a positive identification of an individual allowed to use the parking space. The parking controller can identify the individual through, e.g., a RFID tag, a mobile device (e.g., a remote control, smartphone, tablet, etc.), an access card, biometric information, or other appropriate identifier.

  10. Blood-Brain Barrier Dysfunction as a Hallmark Pathology in Chronic Traumatic Encephalopathy. (United States)

    Doherty, Colin P; O'Keefe, Eoin; Wallace, Eugene; Loftus, Teresa; Keaney, James; Kealy, John; Humphries, Marian M; Molloy, Michael G; Meaney, James F; Farrell, Michael; Campbell, Matthew


    Chronic traumatic encephalopathy (CTE) is a neurodegenerative condition associated with repetitive mild traumatic brain injury. In recent years, attention has focused on emerging evidence linking the development of CTE to concussive injuries in athletes and military personnel; however, the underlying molecular pathobiology of CTE remains unclear. Here, we provide evidence that the blood-brain barrier (BBB) is disrupted in regions of dense perivascular p-Tau accumulation in a case of CTE. Immunoreactivity patterns of the BBB-associated tight junction components claudin-5 and zonula occludens-1 were markedly discontinuous or absent in regions of perivascular p-Tau deposition; there was also immunohistochemical evidence of a BBB in these foci. Because the patient was diagnosed premortem clinically as having progressive supranuclear palsy (PSP), we also compromised that the CTE alterations appear to be distinct from those in the brain of a patient with PSP. This report represents the first description of BBB dysfunction in a pathologically proven CTE case and suggests a vascular component in the postconcussion cascade of events that may ultimately lead to development of a progressive degenerative disorder. BBB dysfunction may represent a correlate of neural dysfunction in live subjects suspected of being at risk for development of CTE. © 2016 American Association of Neuropathologists, Inc. All rights reserved.

  11. Disruption of astrocyte-vascular coupling and the blood-brain barrier by invading glioma cells (United States)

    Watkins, Stacey; Robel, Stefanie; Kimbrough, Ian F.; Robert, Stephanie M.; Ellis-Davies, Graham; Sontheimer, Harald


    Astrocytic endfeet cover the entire cerebral vasculature and serve as exchange sites for ions, metabolites, and energy substrates from the blood to the brain. They maintain endothelial tight junctions that form the blood-brain barrier (BBB) and release vasoactive molecules that regulate vascular tone. Malignant gliomas are highly invasive tumors that use the perivascular space for invasion and co-opt existing vessels as satellite tumors form. Here we use a clinically relevant mouse model of glioma and find that glioma cells, as they populate the perivascular space of pre-existing vessels, displace astrocytic endfeet from endothelial or vascular smooth muscle cells. This causes a focal breach in the BBB. Furthermore, astrocyte-mediated gliovascular coupling is lost, and glioma cells seize control over regulation of vascular tone through Ca2+-dependent release of K+. These findings have important clinical implications regarding blood flow in the tumor-associated brain and the ability to locally deliver chemotherapeutic drugs in disease. PMID:24943270

  12. Association of Coronary Perivascular Adipose Tissue Inflammation and Drug-Eluting Stent-Induced Coronary Hyperconstricting Responses in Pigs:18F-Fluorodeoxyglucose Positron Emission Tomography Imaging Study. (United States)

    Ohyama, Kazuma; Matsumoto, Yasuharu; Amamizu, Hirokazu; Uzuka, Hironori; Nishimiya, Kensuke; Morosawa, Susumu; Hirano, Michinori; Watabe, Hiroshi; Funaki, Yoshihito; Miyata, Satoshi; Takahashi, Jun; Ito, Kenta; Shimokawa, Hiroaki


    Although coronary perivascular adipose tissue (PVAT) may play important roles as a source of inflammation, the association of coronary PVAT inflammation and coronary hyperconstricting responses remains to be examined. We addressed this important issue in a porcine model of coronary hyperconstricting responses after drug-eluting stent implantation with 18 F-fluorodeoxyglucose ( 18 F-FDG) positron emission tomographic imaging. An everolimus-eluting stent (EES) was randomly implanted in pigs into the left anterior descending or the left circumflex coronary artery while nonstented coronary artery was used as a control. After 1 month, coronary vasoconstricting responses to intracoronary serotonin (10 and 100 μg/kg) were examined by coronary angiography in vivo, followed by in vivo and ex vivo 18 F-FDG positron emission tomographic/computed tomographic imaging. Coronary vasoconstricting responses to serotonin were significantly enhanced at the EES edges compared with the control site ( P inflammation. © 2017 American Heart Association, Inc.

  13. Skin barrier function

    DEFF Research Database (Denmark)


    on the subject. It covers new basic research on skin markers, including results on filaggrin and on methods for the assessment of the barrier function. Biological variation and aspects of skin barrier function restoration are discussed as well. Further sections are dedicated to clinical implications of skin...... barrier integrity, factors influencing the penetration of the skin, influence of wet work, and guidance for prevention and saving the barrier. Distinguished researchers have contributed to this book, providing a comprehensive and thorough overview of the skin barrier function. Researchers in the field...

  14. Spironolactone Prevents Endothelial Nitric Oxide Synthase Uncoupling and Vascular Dysfunction Induced by β-Adrenergic Overstimulation: Role of Perivascular Adipose Tissue. (United States)

    Victorio, Jamaira A; Clerici, Stefano P; Palacios, Roberto; Alonso, María J; Vassallo, Dalton V; Jaffe, Iris Z; Rossoni, Luciana V; Davel, Ana P


    Sustained stimulation of β-adrenoceptors (β-ARs) and activation of renin-angiotensin-aldosterone system are common features of cardiovascular diseases with rising sympathetic activation, including essential hypertension, myocardial infarction, and heart failure. In this study, we investigated the role of AT1 receptor and mineralocorticoid receptor (MR) in the vascular alterations caused by β-AR overstimulation. β-AR overstimulation with associated cardiac hypertrophy and increased vasoconstrictor response to phenylephrine in aorta were modeled in rats by 7-day isoproterenol treatment. The increased vasoconstrictor response to phenylephrine in this model was blunted by the MR antagonist spironolactone, but not by the AT1 receptor antagonist losartan, despite the blunting of cardiac hypertrophy with both drugs. Spironolactone, but not losartan, restored NO bioavailability in association with lower endothelial nitric oxide synthase-derived superoxide production, increased endothelial nitric oxide synthase dimerization, and aortic HSP90 upregulation. MR genomic and nongenomic functions were activated in aortas from isoproterenol-treated rats. Isoproterenol did not modify plasma levels of MR ligands aldosterone and corticosterone but rather increased perivascular adipose tissue-derived corticosterone in association with increased expression of 11β-hydroxysteroid dehydrogenase type 1. The anticontractile effect of aortic perivascular adipose tissue was impaired by β-AR overstimulation and restored by MR blockade. These results suggest that activation of vascular MR signaling contributes to the vascular dysfunction induced by β-AR overstimulation associated with endothelial nitric oxide synthase uncoupling. These findings reveal an additional explanation for the protective effects of MR antagonists in cardiovascular disorders with sympathetic activation. © 2016 The Authors.

  15. Loss of perivascular adipose tissue on peroxisome proliferator-activated receptor-γ deletion in smooth muscle cells impairs intravascular thermoregulation and enhances atherosclerosis. (United States)

    Chang, Lin; Villacorta, Luis; Li, Rongxia; Hamblin, Milton; Xu, Wei; Dou, Chunyan; Zhang, Jifeng; Wu, Jiarui; Zeng, Rong; Chen, Y Eugene


    Perivascular adipose tissue (PVAT) surrounds most vessels and shares common features with brown adipose tissue (BAT). Although adaptive thermogenesis in BAT increases energy expenditure and is beneficial for metabolic diseases, little is known about the role of PVAT in vascular diseases such as atherosclerosis. We hypothesize that the thermogenic function of PVAT regulates intravascular temperature and reduces atherosclerosis. PVAT shares similar structural and proteomics with BAT. We demonstrated that PVAT has thermogenic properties similar to BAT in response to cold stimuli in vivo. Proteomics analysis of the PVAT from mice housed in a cold environment identified differential expression in proteins highly related to cellular metabolic processes. In a mouse model deficient in peroxisome proliferator-activated receptor-γ in smooth muscle cells (SMPG KO mice), we uncovered a complete absence of PVAT surrounding the vasculature, likely caused by peroxisome proliferator-activated receptor-γ deletion in the perivascular adipocyte precursor cells as well. Lack of PVAT, which results in loss of its thermogenic activity, impaired vascular homeostasis, which caused temperature loss and endothelial dysfunction. We further showed that cold exposure inhibits atherosclerosis and improves endothelial function in mice with intact PVAT but not in SMPG KO mice as a result of impaired lipid clearance. Proinflammatory cytokine expression in PVAT is not altered on exposure to cold. Finally, prostacyclin released from PVAT contributes to the vascular protection against endothelial dysfunction. PVAT is a vasoactive organ with functional characteristics similar to BAT and is essential for intravascular thermoregulation of cold acclimation. This thermogenic capacity of PVAT plays an important protective role in the pathogenesis of atherosclerosis.

  16. Thermal barriers for compartments

    Energy Technology Data Exchange (ETDEWEB)

    Kreutzer, Cory J.; Lustbader, Jason A.


    An aspect of the present disclosure is a thermal barrier that includes a core layer having a first surface, a second surface, and a first edge, and a first outer layer that includes a third surface and a second edge, where the third surface substantially contacts the first surface, the core layer is configured to minimize conductive heat transfer through the barrier, and the first outer layer is configured to maximize reflection of light away from the barrier.

  17. Tunnel barrier schottky

    Energy Technology Data Exchange (ETDEWEB)

    Chu, Rongming; Cao, Yu; Li, Zijian; Williams, Adam J.


    A diode includes: a semiconductor substrate; a cathode metal layer contacting a bottom of the substrate; a semiconductor drift layer on the substrate; a graded aluminum gallium nitride (AlGaN) semiconductor barrier layer on the drift layer and having a larger bandgap than the drift layer, the barrier layer having a top surface and a bottom surface between the drift layer and the top surface, the barrier layer having an increasing aluminum composition from the bottom surface to the top surface; and an anode metal layer directly contacting the top surface of the barrier layer.

  18. Transforming Education: Overcoming Barriers. (United States)

    David, Jane L.; Goren, Paul D.

    Barriers to progress in educational reform exist inside and outside the education system. Some arise where new practices encounter traditional expectations and boundaries, but others go much deeper than education, such as poverty, racism, local political conflicts, and human resistance to change. The following five categories of barriers are…

  19. Penetration resistant barrier (United States)

    Hoover, William R.; Mead, Keith E.; Street, Henry K.


    The disclosure relates to a barrier for resisting penetration by such as hand tools and oxy-acetylene cutting torches. The barrier comprises a layer of firebrick, which is preferably epoxy impregnated sandwiched between inner and outer layers of steel. Between the firebrick and steel are layers of resilient rubber-like filler.

  20. Elucidation of mechanism of blood-brain barrier damage for prevention and treatment of vascular dementia. (United States)

    Ueno, Masaki


    It is well-known that the blood-brain barrier (BBB) plays significant roles in transporting intravascular substances into the brain. The BBB in cerebral capillaries essentially impedes the influx of intravascular compounds from the blood to the brain, while nutritive substances, such as glucose, can be selectively transported through several types of influx transporters in endothelial cells. In the choroid plexus, intravascular substances can invade the parenchyma as fenestrations exist in endothelial cells of capillaries. However, the substances cannot invade the ventricles easily as there are tight junctions between epithelial cells in the choroid plexus. This restricted movement of the substances across the cytoplasm of the epithelial cells constitutes a blood-cerebrospinal fluid barrier (BCSFB). In the brain, there are circumventricular organs, in which the barrier function is imperfect in capillaries. Accordingly, it is reasonable to consider that intravascular substances can move in and around the parenchyma of the organs. Actually, it was reported in mice that intravascular substances moved in the corpus callosum, medial portions of the hippocampus, and periventricular areas via the subfornical organs or the choroid plexus. Regarding pathways of intracerebral interstitial and cerebrospinal fluids to the outside of the brain, two representative drainage pathways, or perivascular drainage and glymphatic pathways, are being established. The first is the pathway in a retrograde direction to the blood flow through the basement membrane in walls of cerebral capillaries, the tunica media of arteries, and the vessels walls of the internal carotid artery. The second is in an anterograde direction to blood flow through the para-arterial routes, aquaporin 4-dependent transport through the astroglial cytoplasm, and para-venous routes, and then the fluids drain into the subarachnoid CSF. These fluids are finally considered to drain into the cervical lymph nodes or veins

  1. Sex differences in the role of phospholipase A2 -dependent arachidonic acid pathway in the perivascular adipose tissue function in pigs. (United States)

    Ahmad, Abdulla A; Randall, Michael D; Roberts, Richard E


    The fat surrounding blood vessels (perivascular adipose tissue or PVAT) releases vasoactive compounds that regulate vascular smooth muscle tone. There are sex differences in the regulation of vascular tone, but, to date, no study has investigated whether there are sex differences in the regulation of blood vessel tone by PVAT. This study has identified that the cyclooxygenase products thromboxane and PGF2α are released from coronary artery PVAT from pigs. Thromboxane appears to mediate the PVAT-induced contraction in arteries from females, whereas PGF2α appears to mediate the contraction in arteries from males. These sex differences in the role of these prostanoids in the PVAT-induced contraction can be explained by a greater release of thromboxane from PVAT from female animals and greater sensitivity to PGF2α in the porcine coronary artery from males. Previous studies have demonstrated that perivascular adipose tissue (PVAT) causes vasoconstriction. In this present study, we determined the role of cyclooxygenase-derived prostanoids in this contractile response and determined whether there were any sex differences in the regulation of vascular tone by PVAT. Contractions in isolated segments of coronary arteries were determined using isolated tissue baths and isometric tension recording. Segments were initially cleaned of PVAT, which was then re-added to the tissue bath and changes in tone measured over 1 h. Levels of PGF2α and thromboxane B2 (TXB2 ) were quantified by ELISA, and PGF2α (FP) and thromboxane A2 (TP) receptor expression determined by Western blotting. In arteries from both male and female pigs, re-addition of PVAT caused a contraction, which was partially inhibited by the cyclooxygenase inhibitors indomethacin and flurbiprofen. The FP receptor antagonist AL8810 attenuated the PVAT-induced contraction in arteries from males, whereas the TP receptor antagonist GR32191B inhibited the PVAT-induced contraction in arteries from females. Although there

  2. Clip readjustment in aneurysm surgery after flow evaluation using the ultrasonic perivascular probe: case report Reajuste do clipe na cirurgia de aneurisma após avaliação do fluxo arterial por meio de micro-sonda ultrasônica perivascular: relato de caso

    Directory of Open Access Journals (Sweden)

    Walter J. Fagundes-Pereyra


    Full Text Available Occlusion or stenosis of a parent vessel or its distal branches is a major cause of poor patient outcome after cerebral aneurysm surgery. Despite great attempts to preserve patency at the time of clip application, intraoperative visual observation may not reveal arterial compromise or occlusion. Quantitative measurement of blood flow in cerebral vessels during aneurysm surgery can help prevent ischaemia and improve patient outcome. We report a case of a large complex middle cerebral artery (MCA aneurysm in which perivascular microflow probes were used to measure blood flow quantitatively in MCA and its branches before and after aneurysm clipping. Following aneurysm clipping, blood flow in the MCA branches were significantly reduced to less than its initial baseline value with occlusion of the inferior M2 segment. Prompt detection of compromised blood flow gave the surgeon the opportunity to adjust the clip. This adjustment was performed several times until restore MCA flow to its preclipping values. Intraoperative quantitative vessel-flow measurements were safe and may have prevented cerebral ischaemia and neurological deficit to this patient.A medida quantitativa do fluxo sanguíneo nos vasos cerebrais durante a cirurgia de aneurisma pode ajudar na prevenção de eventos isquêmicos e, portanto, melhorar os resultados. Relatamos o caso de paciente portador de aneurisma grande e complexo da bifurcação da artéria de cerebral média (ACM, no qual foram usadas micro-sondas ultrasônicas perivasculares para medir o fluxo de sangue quantitativamente na ACM e nos seus ramos antes e depois da clipagem do aneurisma. Após a clipagem do aneurisma, o fluxo de sangue diminuiu em todos os ramos, fazendo-se necessário o reajuste do clipe. Após vários ajustes na posição do clipe, o fluxo sanguíneo nos segmentos da ACM foi restabelecido. A descoberta imediata da alteração do fluxo de sangue proporcionou a oportunidade ao cirurgião de ajuste do

  3. Complementary Barrier Infrared Detector (United States)

    Ting, David Z.; Bandara, Sumith V.; Hill, Cory J.; Gunapala, Sarath D.


    The complementary barrier infrared detector (CBIRD) is designed to eliminate the major dark current sources in the superlattice infrared detector. The concept can also be applied to bulk semiconductor- based infrared detectors. CBIRD uses two different types of specially designed barriers: an electron barrier that blocks electrons but not holes, and a hole barrier that blocks holes but not electrons. The CBIRD structure consists of an n-contact, a hole barrier, an absorber, an electron barrier, and a p-contact. The barriers are placed at the contact-absorber junctions where, in a conventional p-i-n detector structure, there normally are depletion regions that produce generation-recombination (GR) dark currents due to Shockley-Read- Hall (SRH) processes. The wider-bandgap complementary barriers suppress G-R dark current. The barriers also block diffusion dark currents generated in the diffusion wings in the neutral regions. In addition, the wider gap barriers serve to reduce tunneling dark currents. In the case of a superlattice-based absorber, the superlattice itself can be designed to suppress dark currents due to Auger processes. At the same time, the barriers actually help to enhance the collection of photo-generated carriers by deflecting the photo-carriers that are diffusing in the wrong direction (i.e., away from collectors) and redirecting them toward the collecting contacts. The contact layers are made from materials with narrower bandgaps than the barriers. This allows good ohmic contacts to be made, resulting in lower contact resistances. Previously, THALES Research and Technology (France) demonstrated detectors with bulk InAsSb (specifically InAs0.91Sb0.09) absorber lattice-matched to GaSb substrates. The absorber is surrounded by two wider bandgap layers designed to minimize impedance to photocurrent flow. The wide bandgap materials also serve as contacts. The cutoff wavelength of the InAsSb absorber is fixed. CBIRD may be considered as a modified

  4. Enhancement of Perivascular Spaces in 7 T MR Image using Haar Transform of Non-local Cubes and Block-matching Filtering. (United States)

    Hou, Yingkun; Park, Sang Hyun; Wang, Qian; Zhang, Jun; Zong, Xiaopeng; Lin, Weili; Shen, Dinggang


    Perivascular spaces (PVSs) in brain have a close relationship with typical neurological diseases. The quantitative studies of PVSs are meaningful but usually difficult, due to their thin and weak signals and also background noise in the 7 T brain magnetic resonance images (MRI). To clearly distinguish the PVSs in the 7 T MRI, we propose a novel PVS enhancement method based on the Haar transform of non-local cubes. Specifically, we extract a certain number of cubes from a small neighbor to form a cube group, and then perform Haar transform on each cube group. The Haar transform coefficients are processed using a nonlinear function to amplify the weak signals relevant to the PVSs and to suppress the noise. The enhanced image is reconstructed using the inverse Haar transform of the processed coefficients. Finally, we perform a block-matching 4D filtering on the enhanced image to further remove any remaining noise, and thus obtain an enhanced and denoised 7 T MRI for PVS segmentation. We apply two existing methods to complete PVS segmentation, i.e., (1) vesselness-thresholding and (2) random forest classification. The experimental results show that the PVS segmentation performances can be significantly improved by using the enhanced and denoised 7 T MRI.

  5. Human umbilical cord perivascular cells exhibited enhanced migration capacity towards hepatocellular carcinoma in comparison with bone marrow mesenchymal stromal cells: a role for autocrine motility factor receptor. (United States)

    Bayo, Juan; Fiore, Esteban; Aquino, Jorge B; Malvicini, Mariana; Rizzo, Manglio; Peixoto, Estanislao; Alaniz, Laura; Piccioni, Flavia; Bolontrade, Marcela; Podhajcer, Osvaldo; Garcia, Mariana G; Mazzolini, Guillermo


    Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. Unfortunately, the incidence and mortality associated with HCC are increasing. Therefore, new therapeutic strategies are urgently needed and the use of mesenchymal stromal cells (MSCs) as carrier of therapeutic genes is emerging as a promising option. Different sources of MSCs are being studied for cell therapy and bone marrow-derived cells are the most extensively explored; however, birth associated-tissues represent a very promising source. The aim of this work was to compare the in vitro and in vivo migration capacity between bone marrow MSCs (BM-MSCs) and human umbilical cord perivascular cells (HUCPVCs) towards HCC. We observed that HUCPVCs presented higher in vitro and in vivo migration towards factors released by HCC. The expression of autocrine motility factor (AMF) receptor, genes related with the availability of the receptor on the cell surface (caveolin-1 and -2) and metalloproteinase 3, induced by the receptor activation and important for cell migration, was increased in HUCPVCs. The chemotactic response towards recombinant AMF was increased in HUCPVCs compared to BM-MSCs, and its inhibition in the conditioned medium from HCC induced higher decrease in HUCPVC migration than in BM-MSC. Our results indicate that HUCPVCs could be a useful cellular source to deliver therapeutic genes to HCC.

  6. H2O2 generated from mitochondrial electron transport chain in thoracic perivascular adipose tissue is crucial for modulation of vascular smooth muscle contraction. (United States)

    Costa, Rafael M; Filgueira, Fernando P; Tostes, Rita C; Carvalho, Maria Helena C; Akamine, Eliana H; Lobato, Nubia S


    The perivascular adipose tissue (PVAT) releases a variety of factors that affect vascular function. PVAT in the thoracic aorta shares characteristics with the brown adipose tissue, including a large amount of mitochondria. PVAT-derived factors influence both endothelial and smooth muscle function via several signaling mechanisms including the release/generation of reactive nitrogen and oxygen species. Considering the importance of reactive oxygen species (ROS) on vascular function and that mitochondria are an important source of ROS, we hypothesized that mitochondria-derived ROS in the PVAT modulates vascular reactivity. Vascular reactivity to norephinephrine (NE) was evaluated in thoracic aortic rings, with or without endothelium and/or PVAT, from male Wistar rats. Mitochondrial uncoupling, as well as hydrogen peroxide (H2O2) removal, increased the contraction in vessels surrounded by PVAT. PVAT stimulated with NE exhibited increased protein expression, determined by Western blot analysis, of manganese superoxide dismutase (Mn-SOD) and decreased protein expression of catalase. Ultimately, NE increased superoxide anion (O2(-)) generation in PVAT via increases in intracellular calcium. These results clearly demonstrate that mitochondrial electron transport chain (mETC) in PVAT contributes to modulation of aortic muscle contraction by generating higher amounts of O2(-) that is, in turn, dismutated to hydrogen peroxide, which then acts as a pivotal signaling molecule regulating vascular smooth muscle contraction. Copyright © 2015 Elsevier Inc. All rights reserved.

  7. Human Umbilical Cord Perivascular Cells Exhibited Enhanced Migration Capacity towards Hepatocellular Carcinoma in Comparison with Bone Marrow Mesenchymal Stromal Cells: A Role for Autocrine Motility Factor Receptor

    Directory of Open Access Journals (Sweden)

    Juan Bayo


    Full Text Available Hepatocellular carcinoma (HCC is the third cause of cancer-related death worldwide. Unfortunately, the incidence and mortality associated with HCC are increasing. Therefore, new therapeutic strategies are urgently needed and the use of mesenchymal stromal cells (MSCs as carrier of therapeutic genes is emerging as a promising option. Different sources of MSCs are being studied for cell therapy and bone marrow-derived cells are the most extensively explored; however, birth associated-tissues represent a very promising source. The aim of this work was to compare the in vitro and in vivo migration capacity between bone marrow MSCs (BM-MSCs and human umbilical cord perivascular cells (HUCPVCs towards HCC. We observed that HUCPVCs presented higher in vitro and in vivo migration towards factors released by HCC. The expression of autocrine motility factor (AMF receptor, genes related with the availability of the receptor on the cell surface (caveolin-1 and -2 and metalloproteinase 3, induced by the receptor activation and important for cell migration, was increased in HUCPVCs. The chemotactic response towards recombinant AMF was increased in HUCPVCs compared to BM-MSCs, and its inhibition in the conditioned medium from HCC induced higher decrease in HUCPVC migration than in BM-MSC. Our results indicate that HUCPVCs could be a useful cellular source to deliver therapeutic genes to HCC.

  8. Converse Barrier Certificate Theorems

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer


    This paper shows that a barrier certificate exists for any safe dynamical system. Specifically, we prove converse barrier certificate theorems for a class of structurally stable dynamical systems. Other authors have developed a related result by assuming that the dynamical system has neither...... singular points nor closed orbits. In this paper, we redefine the standard notion of safety to comply with dynamical systems with multiple singular elements. Hereafter, we prove the converse barrier certificate theorems and highlight the differences between our results and previous work by a number...

  9. Converse Barrier Certificate Theorem

    DEFF Research Database (Denmark)

    Wisniewski, Rafael; Sloth, Christoffer


    This paper presents a converse barrier certificate theorem for a generic dynamical system.We show that a barrier certificate exists for any safe dynamical system defined on a compact manifold. Other authors have developed a related result, by assuming that the dynamical system has no singular...... points in the considered subset of the state space. In this paper, we redefine the standard notion of safety to comply with generic dynamical systems with multiple singularities. Afterwards, we prove the converse barrier certificate theorem and illustrate the differences between ours and previous work...

  10. Recycler barrier RF buckets

    Energy Technology Data Exchange (ETDEWEB)

    Bhat, C.M.; /Fermilab


    The Recycler Ring at Fermilab uses a barrier rf systems for all of its rf manipulations. In this paper, I will give an overview of historical perspective on barrier rf system, the longitudinal beam dynamics issues, aspects of rf linearization to produce long flat bunches and methods used for emittance measurements of the beam in the RR barrier rf buckets. Current rf manipulation schemes used for antiproton beam stacking and longitudinal momentum mining of the RR beam for the Tevatron collider operation are explained along with their importance in spectacular success of the Tevatron luminosity performance.

  11. Papel del tejido perivascular en la regulación del tono vascular: repercusión en el uso de puentes aorto-coronarios para revascularización miocárdica Role of perivascular tissue in vascular tone regulation: repercussion in the use of aortocoronary bypass for myocardial revascularization

    Directory of Open Access Journals (Sweden)

    Patricio López-Jaramillo

    Full Text Available Desde hace más de treinta años, la inserción quirúrgica de puentes aorto-coronarios autólogos de vena safena y de arteria mamaria, constituye el tratamiento de elección para pacientes con enfermedad coronaria severa. La vida útil de estos injertos ha demostrado ser mayor en los colgajos de tipo arterial, aunque su uso está limitado por la restringida disponibilidad de los mismos. Por esta razón, y a pesar de que tienen mayor riesgo de presentar oclusión, los injertos de vena safena son los que más se usan en estos procedimientos de reperfusión miocárdica. Aún no se han esclarecido del todo las razones por las cuales los injertos venosos se ocluyen luego de su inserción en los lechos arteriales; no obstante, se ha propuesto que podría deberse a diferentes factores como: trauma mecánico quirúrgico, aumento de la presión arterial y disminuido estrés de fricción. En 1996 se describió la técnica "no-touch" de preparación de los injertos venosos, en la cual se implantaron los puentes venosos en los lechos coronarios junto con el tejido peri-vascular que los circunda, y demostró mejorar la vida útil de este tipo de injertos. Recientemente se ha propuesto que el tejido adiposo peri-vascular podría desempeñar un papel en la regulación del tono vascular, e incluso se ha descrito la existencia de un factor relajante derivado del adipocito (ADRF, cuya naturaleza no se ha esclarecido completamente. El objetivo de este articulo es revisar los diferentes factores vinculados con la oclusión de los injertos aorto-coronarios, las posibles vías fisiopatológicas que configuran este fenómeno, las nuevas alternativas quirúrgicas utilizadas para la preparación de los injertos venosos y los avances en la descripción del ADRF y su papel en la regulación del tono vascular.Since more than thirty years, surgical insertion of autologous aortocoronary bypasses from saphenous vein and mammary artery constitute the election treatment for

  12. California highway barrier aesthetics (United States)


    This report will familiarize designers with current barrier design options, and encourage appropriate aesthetic considerations to develop visually pleasing context sensitive solutions for highway projects. Technical guidelines allow integral color, p...

  13. Hedging Double Barriers with Singles

    NARCIS (Netherlands)

    Sbuelz, A.


    Double barrier options provide risk managers with good-deal flexibility in tailoring portfolio returns.Their hedges offer full protection only if unwound along the barriers.This work provides non-dynamic hedges that project the risk of double barriers on to single barriers.Non-dynamic hedges

  14. Barriers to effective teaching. (United States)

    DaRosa, Debra A; Skeff, Kelley; Friedland, Joan A; Coburn, Michael; Cox, Susan; Pollart, Susan; O'connell, Mark; Smith, Sandy


    Medical school faculty members are charged with the critical responsibility of preparing the future physician and medical scientist workforce. Recent reports suggest that medical school curricula have not kept pace with societal needs and that medical schools are graduating students who lack the knowledge and skills needed to practice effectively in the 21st century. The majority of faculty members want to be effective teachers and graduate well-prepared medical students, but multiple and complex factors-curricular, cultural, environmental, and financial-impede their efforts. Curricular impediments to effective teaching include unclear definitions of and disagreement on learning needs, misunderstood or unstated goals and objectives, and curriculum sequencing challenges. Student and faculty attitudes, too few faculty development opportunities, and the lack of an award system for teaching all are major culture-based barriers. Environmental barriers, such as time limitations, the setting, and the physical space in which medical education takes place, and financial barriers, such as limited education budgets, also pose serious challenges to even the most committed teachers. This article delineates the barriers to effective teaching as noted in the literature and recommends action items, some of which are incremental whereas others represent major change. Physicians-in-training, medical faculty, and society are depending on medical education leaders to address these barriers to effect the changes needed to enhance teaching and learning. © by the Association of American Medical Colleges.

  15. Effect of long-term treatment with melatonin on vascular markers of oxidative stress/inflammation and on the anticontractile activity of perivascular fat in aging mice. (United States)

    Agabiti-Rosei, Claudia; Favero, Gaia; De Ciuceis, Carolina; Rossini, Claudia; Porteri, Enzo; Rodella, Luigi Fabrizio; Franceschetti, Lorenzo; Maria Sarkar, Anna; Agabiti-Rosei, Enrico; Rizzoni, Damiano; Rezzani, Rita


    Some reports have suggested that inflammation in perivascular adipose tissue (PVAT) may be implicated in vascular dysfunction by causing the disappearance of an anticontractile effect. The aim of this study was to investigate the effects of chronic melatonin treatment on the functional responses of the small mesenteric arteries and on the expression of markers of inflammation/oxidative stress in the aortas of senescence-accelerated prone mice (SAMP8), a model of age-related vascular dysfunction. We investigated seven SAMP8 and seven control senescence-accelerated resistant mice (SAMR1) treated for 10 months with melatonin, as well as equal numbers of age-matched untreated SAMP8 and SAMR1. The mesenteric small resistance arteries were dissected and mounted on a wire myograph, and the concentration-response to norepinephrine was evaluated in vessels with intact PVAT and after the removal of the PVAT. The expression of markers of oxidative stress, inflammation and aging in the aortas was evaluated by immunostaining. In addition, the adiponectin content and the expression of adiponectin receptor 1 were evaluated in the visceral adipose tissue. In untreated SAMP8 mice, we observed an overexpression of oxidative stress and inflammatory markers in the vasculature compared with the controls. No anticontractile effect of the PVAT was observed in untreated SAMP8 mice. Long-term treatment of SAMP8 mice with melatonin increased the expression of some markers of vasoprotection, decreased oxidative stress and inflammation and restored the anticontractile effect of the PVAT. Decreased expression of adiponectin and adiponectin receptor 1 was also observed in visceral fat of untreated SAMP8, whereas a significant increase was observed after melatonin treatment.

  16. Skin barrier in rosacea* (United States)

    Addor, Flavia Alvim Sant'Anna


    Recent studies about the cutaneous barrier demonstrated consistent evidence that the stratum corneum is a metabolically active structure and also has adaptive functions, may play a regulatory role in the inflammatory response with activation of keratinocytes, angiogenesis and fibroplasia, whose intensity depends primarily on the intensity the stimulus. There are few studies investigating the abnormalities of the skin barrier in rosacea, but the existing data already show that there are changes resulting from inflammation, which can generate a vicious circle caused a prolongation of flare-ups and worsening of symptoms. This article aims to gather the most relevant literature data about the characteristics and effects of the state of the skin barrier in rosacea. PMID:26982780

  17. Health Barriers to Learning

    Directory of Open Access Journals (Sweden)

    Delaney Gracy


    Full Text Available This article summarizes the results from a 2013 online survey with 408 principals and assistant principals in New York City public elementary and middle schools. The survey assessed three primary areas: health issues in the school, health issues perceived as barriers to learning for affected students, and resources needed to address these barriers. Eighteen of the 22 health conditions listed in the survey were considered a moderate or serious issue within their schools by at least 10% of respondents. All 22 of the health issues were perceived as a barrier to learning by between 12% and 87% of the respondents. Representatives from schools that serve a higher percentage of low-income students reported significantly higher levels of concern about the extent of health issues and their impact on learning. Respondents most often said they need linkages with organizations that can provide additional services and resources at the school, especially for mental health.

  18. Barrier distributions and scattering

    Energy Technology Data Exchange (ETDEWEB)

    Timmers, H.; Leigh, J.R.; Dasgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Department of Nuclear Physics, Australian National University, Canberra, ACT 0200 (Austria); Rowley, N. [Centre de Recherches Nucleaires, 23 Rue du Loess, F-67037 Strasbourg CEDEX 2 (France); Stefanini, A.M.; Ackermann, D.; Corradi, L.; He, J.H. [INFN, Laboratori Nazionali di Legnaro, Legnaro (PD) (Italy); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.F. [Universita di Padova and INFN Sezione di Padova, Padova (Italy)


    The extraction of representations of the fusion barrier distribution from backward-angle, quasi-elastic, elastic and transfer excitation functions is discussed. Such excitation functions have been measured for {sup 16}O, {sup 32}S and {sup 40}Ca projectiles incident on a variety of targets. The results are compared with representations obtained from fusion excitation functions. Varying in their sensitivity, all representations show evidence of the barrier structure. Differences between the scattering and the fusion representations can be related to the effects of coupling to residual, weak reaction channels. (author)

  19. Great Barrier Reef (United States)


    A better than average view of the Great Barrier Reef was captured by SeaWiFS on a recent overpass. There is sunglint northeast of the reef and there appears to be some sort of filamentous bloom in the Capricorn Channel.

  20. Support or Barrier?

    DEFF Research Database (Denmark)

    Sanden, Guro Refsum; Lønsmann, Dorte

    This study offers a critical look at how corporate-level language management influences front-line language practices among employees in three multinational corporations (MNCs) headquartered in Scandinavia. Based on interview and document data, we examine, firstly, what front-line practices emplo...... to a discussion of how a company’s language policy may be seen as both support and a barrier....

  1. Tight junctions at the blood brain barrier: physiological architecture and disease-associated dysregulation

    Directory of Open Access Journals (Sweden)

    Luissint Anny-Claude


    Full Text Available Abstract The Blood–brain barrier (BBB, present at the level of the endothelium of cerebral blood vessels, selectively restricts the blood-to-brain paracellular diffusion of compounds; it is mandatory for cerebral homeostasis and proper neuronal function. The barrier properties of these specialized endothelial cells notably depend on tight junctions (TJs between adjacent cells: TJs are dynamic structures consisting of a number of transmembrane and membrane-associated cytoplasmic proteins, which are assembled in a multimolecular complex and acting as a platform for intracellular signaling. Although the structural composition of these complexes has been well described in the recent years, our knowledge about their functional regulation still remains fragmentary. Importantly, pericytes, embedded in the vascular basement membrane, and perivascular microglial cells, astrocytes and neurons contribute to the regulation of endothelial TJs and BBB function, altogether constituting the so-called neurovascular unit. The present review summarizes our current understanding of the structure and functional regulation of endothelial TJs at the BBB. Accumulating evidence points to a correlation between BBB dysfunction, alteration of TJ complexes and progression of a variety of CNS diseases, such as stroke, multiple sclerosis and brain tumors, as well as neurodegenerative diseases like Parkinson’s and Alzheimer’s diseases. Understanding how TJ integrity is controlled may thus help improve drug delivery across the BBB and the design of therapeutic strategies for neurological disorders.

  2. Conditioned medium from the three-dimensional culture of human umbilical cord perivascular cells accelerate the migration and proliferation of human keratinocyte and fibroblast. (United States)

    Kim, Min Ho; Wu, Wen Hao; Choi, Jee Hyun; Kim, Ji Hyun; Hong, Seok-Ho; Jun, Jin Hyun; Ko, Yong; Lee, Jong Hun


    Previous studies have reported that the conditioned medium (CM) of bone marrow-mesenchymal stem cells (BM-MSCs) stimulate the migration and proliferation of cell types involved in the wound healing process. However, these studies only show MSC-CM effects that were obtained using a two-dimensional (2D) culture. Recently, a three-dimensional (3D) culture has been considered to be a more physiologically appropriate system than the 2D culture. In addition, it has been shown that the procurement of BM-MSC is invasive, and other sources of MSC are thus being explored. Recently, perivascular cells (PVCs) have been considered as an alternative source of cells for dermal wound healing. Therefore, in this study, a PVC-conditioned medium (CM) was collected from a 3D culture (PVC-CM-3D) using highly porous polystyrene-based membranes and compared with PVC-CM from a 2D culture (PVC-CM-2D) to investigate the effects on the migration and proliferation of human keratinocytes and fibroblasts. Moreover, the PVC-CM components from the 2D and 3D cultures were identified using 2D gel electrophoresis. The migrations of the keratinocytes cells and fibroblasts were significantly higher with PVC-CM-3D than with the 2D culture; similarly, the proliferation of keratinocytes was also highly stimulated by PVC-CM-3D. Proteomic analyses of the PVC-CM revealed that type I collagen was highly expressed in the 3D-culture system. Microtubule-actin cross-linked factor 1 (KIAA0465), nebulin-related anchoring protein, and thioredoxin were specifically expressed only in PVC-CM-3D. In addition, more EVs could be isolated from the PVC-CM-3D, and EVs were found to stimulate keratinocyte migration. Taken together, 3D-culture using a polystyrene scaffold is demonstrated to be a better system for providing better physiological conditions; therefore, PVC-CM-3D could be a promising option for skin-wound healing.

  3. Carotid extra-media thickness in obesity and metabolic syndrome: a novel index of perivascular adipose tissue: extra-media thickness in obesity and metabolic syndrome. (United States)

    Haberka, Maciej; Gąsior, Zbigniew


    We aimed to evaluate the association between a novel ultrasound index extra-media thickness (EMT), obesity, and metabolic syndrome (MS) using several measures of adiposity. Four hundred patients were included in the study (age: 60.95 ± 7.3 years, F/M: 35/65%). Both common carotid arteries (CCA) indexes (EMT and intima-media thickness), anthropometric parameters, body fat percentage and ultrasound measures of different fat depots were obtained in all patients. MS was identified using three alternative definitions: International Diabetes Federation 2005 (IDF), National Cholesterol Education Program Adult Treatment Panel III 2001 (NCEP ATP III) and World Health Organization 1998 (WHO). The study group included patients with very high (80.2%) or high (19.8%) CV risk (IDF MS: 59.5%). Carotid EMT measures averaged from both sides (±SD) were as follows: mean EMT: 791 ± 126 μm, mean minimum EMT: 731 ± 115 μm and mean maximum EMT: 885 ± 210 μm. Patients with MS, irrespective of its definition and measures of obesity, displayed significantly thicker mean EMT compared to non-MS individuals: 819 ± 129 μm vs 747 ± 113 μm (p < 0.001; IDF), 824 ± 131 μm vs 751 ± 112 μm (p < 0.001; NCEP ATP III) and 825 ± 137 μm vs 773 ± 120 μm (p < 0.001; WHO). Moreover, EMT was related to all major parameters of general obesity, abdominal fat distribution, regional neck subcutaneous fat with weaker association between EMT and epicardial fat thickness. Finally, EMT is associated with an increasing number of CV risk factors. This is the first study providing novel findings on the relationship between EMT, MS, and adiposity indexes. Our results suggest that EMT may be a new non-invasive index of perivascular adipose tissue corresponding to cardiometabolic risk. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. A histomorphometric study on the effects of antiretroviral therapy (ART) combined with a high-calorie diet (HCD) on aortic perivascular adipose tissue (PVAT). (United States)

    Nel, S; Strijdom, H; Genis, A; Everson, F; Van Wijk, R; Kotzé, S H


    Perivascular adipose tissue (PVAT), surrounding arteries is metabolically active. Obesity and antiretroviral therapy (ART) may cause pathophysiological conditions in the aortic wall and surrounding PVAT. The aim of the study was to determine the histological effects on the aortic wall, aortic PVAT adipocyte morphology and leptin staining intensity in obese rats treated with ART. Wistar rats (N=36) were divided into four groups; a lean control (C/ART-), ART control (C/ART+), high-calorie diet (HCD) untreated (HCD/ART-) and HCD and ART experimental (HCD/ART+). The aorta and surrounding PVAT were stained with haematoxylin and eosin (H&E) and anti-leptin antibodies for immunohistochemistry (IHC). The C/ART+ group had a thinner tunica media compared to the HCD/ART- group. The tunica adventitia was thicker in the ART groups (C/ART+ and HCD/ART+) compared to the lean control group. White adipocytes in the HCD/ART- group was larger in size compared to the other three groups. The high-calorie diet groups (HCD/ART- and HCD/ART+) had increased adipocyte sizes, for both brown and differentiating adipocytes, compared to the control groups (C/ART- and C/ART+). The unilocular and differentiating adipocytes in the C/ART+ group showed intense leptin staining. Unilocular and differentiating adipocytes in the HCD/ART- and HCD/ART+ groups showed weak to no leptin staining intensity. The present study indicated that ART and a HCD, separately and combined, altered both the tunica media and adventitia of the aortic wall, whereas the HCD alone caused adipocytes to increase in size. The leptin staining intensity suggested that ART alone may lead to increased leptin expression, whereas ART combined with a HCD may cause leptin deficiency. Changes seen with ART in a rat model suggest that aortic wall thickness and PVAT adipocyte morphology alterations should be considered by clinicians in obese individuals receiving ART. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Perivascular cells for regenerative medicine

    NARCIS (Netherlands)

    M. Crisan (Mihaela); M. Corselli (Mirko); W.C. Chen (William); B. Péault (Bruno)


    textabstractMesenchymal stem/stromal cells (MSC) are currently the best candidate therapeutic cells for regenerative medicine related to osteoarticular, muscular, vascular and inflammatory diseases, although these cells remain heterogeneous and necessitate a better biological characterization. We

  6. Penetration through the Skin Barrier

    DEFF Research Database (Denmark)

    Nielsen, Jesper Bo; Benfeldt, Eva; Holmgaard, Rikke


    and exogenous factors may affect barrier characteristics. The present chapter introduces the theory for barrier penetration (Fick's law), and describes and discusses different methods for measuring the kinetics of percutaneous penetration of chemicals, including in vitro methods (static and flow...

  7. Apoplastic Diffusion Barriers in Arabidopsis (United States)

    Schreiber, Lukas; Franke, Rochus Benni; Geldner, Niko; Reina-Pinto, José J.; Kunst, Ljerka


    During the development of Arabidopsis and other land plants, diffusion barriers are formed in the apoplast of specialized tissues within a variety of plant organs. While the cuticle of the epidermis is the primary diffusion barrier in the shoot, the Casparian strips and suberin lamellae of the endodermis and the periderm represent the diffusion barriers in the root. Different classes of molecules contribute to the formation of extracellular diffusion barriers in an organ- and tissue-specific manner. Cutin and wax are the major components of the cuticle, lignin forms the early Casparian strip, and suberin is deposited in the stage II endodermis and the periderm. The current status of our understanding of the relationships between the chemical structure, ultrastructure and physiological functions of plant diffusion barriers is discussed. Specific aspects of the synthesis of diffusion barrier components and protocols that can be used for the assessment of barrier function and important barrier properties are also presented. PMID:24465172

  8. and use of barrier techniques

    African Journals Online (AJOL)

    consistent use of barrier techniques. Key-words: Attitudes, Dentists, Hepatitis B vaccination,. Barrier techniques. Résumé. Objectif: Virus Hépatite B constitue une menace importante pour le bien ... vacination contre hépatite B ct l'utilisation des techniques do la barriere. .... to staff and rarely from dentist to patients However,.

  9. Can-Filled Crash Barrier (United States)

    Wilson, A. H.


    Crash barrier composed largely of used aluminum beverage cans protects occupants of cars in collisions with poles or trees. Lightweight, can-filled barrier very effective in softening impact of an automobile in head-on and off-angle collisions. Preliminary results indicate barrier is effective in collisions up to 40 mi/h (64 km/h).

  10. [The cultural barrier in care]. (United States)

    Djadaoudjee, Lisa


    French cultural diversity is evident within French hospitals, where nurses are confronted with communication problems resulting from the language barrier. While communication is indeed essential, there is another important aspect of caring for a patient for behind the language barrier lies a cultural barrier which must be taken into account in order to provide high-quality care.

  11. Barriers for recess physical activity

    DEFF Research Database (Denmark)

    Pawlowski, Charlotte Skau; Tjørnhøj-Thomsen, Tine; Schipperijn, Jasper


    differences in children's perceptions of barriers to recess physical activity. Based on the socio-ecological model four types of environmental barriers were distinguished: natural, social, physical and organizational environment. METHODS: Data were collected through 17 focus groups (at 17 different schools......BACKGROUND: Many children, in particular girls, do not reach the recommended amount of daily physical activity. School recess provides an opportunity for both boys and girls to be physically active, but barriers to recess physical activity are not well understood. This study explores gender...... and girls identified the same barriers, there were both inter- and intra-gender differences in the perception of these barriers. Weather was a barrier for all children, apart from the most active boys. Conflicts were perceived as a barrier particularly by those boys who played ballgames. Girls said...

  12. Barrier mechanisms in the Drosophila blood-brain barrier

    Directory of Open Access Journals (Sweden)

    Samantha Jane Hindle


    Full Text Available The invertebrate blood-brain barrier field is growing at a rapid pace and, in recent years, studies have shown a physiologic and molecular complexity that has begun to rival its vertebrate counterpart. Novel mechanisms of paracellular barrier maintenance through GPCR signaling were the first demonstrations of the complex adaptive mechanisms of barrier physiology. Building upon this work, the integrity of the invertebrate blood-brain barrier has recently been shown to require coordinated function of all layers of the compound barrier structure, analogous to signaling between the layers of the vertebrate neurovascular unit. These findings strengthen the notion that many blood-brain barrier mechanisms are conserved between vertebrates and invertebrates, and suggest that novel findings in invertebrate model organisms will have a significant impact on the understanding of vertebrate BBB functions. In this vein, important roles in coordinating localized and systemic signaling to dictate organism development and growth are beginning to show how the blood-brain barrier can govern whole animal physiologies. This includes novel functions of blood-brain barrier gap junctions in orchestrating synchronized neuroblast proliferation, and of blood-brain barrier secreted antagonists of insulin receptor signaling. These advancements and others are pushing the field forward in exciting new directions. In this review, we provide a synopsis of invertebrate blood-brain barrier anatomy and physiology, with a focus on insights from the past 5 years, and highlight important areas for future study.

  13. [Barrier methods of contraception]. (United States)

    Goldsmith, A; Edelman, D A


    Vaginal methods of contraception were the earliest types used and some references to them date back to antiquity. Most of the vaginal contraceptive agents identified by the ancient Greeks, Indians, Japanese, and Chinese have been found in modern laboratory tests to have spermicidal properties, but it is doubtful that the methods were fully reliable or were used by many people. During the 19th century the condom, vaginal spermicides, and diaphragm became available. The development of nonoxynol-9 and other nonirritating but effective spermicidal agents improved vaginal contraceptives greatly by the 1950s, but starting in the 1960s newer methods began to replace the vaginal methods. Interest in barrier methods has been reawakened somewhat by concern about the health effects of hormonal methods. At present all barrier methods leave something to be desired. Failure rates of 3-30% for barrier methods in general have been estimated, but the higher rates are believed due to incorrect or inconsistent use. Theoretical failure rates of condoms and diaphragms have been estimated at 3/100 women-years, but in actual use failure rates may reach 15 for condoms and 13 for diaphragms used with spermicides. Use-effectiveness rates are greatly influenced by motivation. For a variety of reasons, the acceptability of barrier methods is low, especially in developing countries. New developments in spermicidal agents include sperm inhibitors, which impede the fertilizing capacity of sperm rather than attempting a spermicidal effect; a number of such agents have been studied and have proven more effective in animal tests than conventional spermicides. Neosampoon, a new spermicidal foam, has attracted an increasing number of users, especially in developing countries. A new condom, made of thin polymers and containing a standard dose of nonoxynol-9, has been designed to dissolve in the vaginal fluid. Further studies are needed of its acceptability, efficacy, and side effects before it becomes

  14. Non-invasive assessment of blood-brain barrier (BBB) permeability using a gamma camera to detect 99technetium-gluceptate extravasation in rat brain. (United States)

    Esposito, P; Jacobson, S; Connolly, R; Gheorghe, D; Theoharides, T C


    The blood-brain barrier (BBB) is a complex structure of endothelial cells, astroglia, pericytes, and perivascular macrophages enclosed by basal lamina. The BBB regulates the entry of blood-borne molecules and cells into the brain, but it is disrupted in various inflammatory conditions of the central nervous system (CNS). We previously showed that 30 min of immobilization stress increased 99technetium-gluceptate (99Tc) extravasation, measured by a gamma counter, in brain regions containing mast cells, an effect blocked by the mast cell stabilizer disodium cromoglycate [Brain Res. 888 (2001) 117]. Here we report the use of a gamma camera to assess BBB permeability by assessing 99Tc extravasation in the rat brain, during and following acute stress, without having to sacrifice the experimental animals. This method also allows for repeated experimentation on the same animal, since the half-life of 99Tc is only 6 h, and permits testing of potential inhibitors of BBB permeability.

  15. Comparison of radial 4D Flow-MRI with perivascular ultrasound to quantify blood flow in the abdomen and introduction of a porcine model of pre-hepatic portal hypertension. (United States)

    Frydrychowicz, A; Roldan-Alzate, A; Winslow, E; Consigny, D; Campo, C A; Motosugi, U; Johnson, K M; Wieben, O; Reeder, S B


    Objectives of this study were to compare radial time-resolved phase contrast magnetic resonance imaging (4D Flow-MRI) with perivascular ultrasound (pvUS) and to explore a porcine model of acute pre-hepatic portal hypertension (PHTN). Abdominal 4D Flow-MRI and pvUS in portal and splenic vein, hepatic and both renal arteries were performed in 13 pigs of approximately 60 kg. In six pigs, measurements were repeated after partial portal vein (PV) ligature. Inter- and intra-reader comparisons and statistical analysis including Bland-Altman (BA) comparison, paired Student's t tests and linear regression were performed. PvUS and 4D Flow-MRI measurements agreed well; flow before partial PV ligature was 322 ± 30 ml/min in pvUS and 297 ± 27 ml/min in MRI (p = 0.294), and average BA difference was 25 ml/min [-322; 372]. Inter- and intra-reader results differed very little, revealed excellent correlation (R 2 = 0.98 and 0.99, respectively) and resulted in BA differences of -5 ml/min [-161; 150] and -2 ml/min [-28; 25], respectively. After PV ligature, PV flow decreased from 356 ± 50 to 298 ± 61 ml/min (p = 0.02), and hepatic arterial flow increased from 277 ± 36 to 331 ± 65 ml/min (p = n.s.). The successful in vivo comparison of radial 4D Flow-MRI to perivascular ultrasound revealed good agreement of abdominal blood flow although with considerable spread of results. A model of pre-hepatic PHTN was successfully introduced and acute responses monitored. • Radial 4D Flow-MRI in the abdomen was successfully compared to perivascular ultrasound. • Inter- and intra-reader testing demonstrated excellent reproducibility of upper abdominal 4D Flow-MRI. • A porcine model of acute pre-hepatic portal hypertension was successfully introduced. • 4D Flow-MRI successfully monitored acute changes in a model of portal hypertension.

  16. Countermeasures and barriers

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Johannes [Oersted - DTU, Automation, Kgs. Lyngby (Denmark)


    In 1973 Haddon proposed ten strategies for reducing and avoiding damages based on a model of potential harmful energy transfer (Haddon, 1973). The strategies apply to a large variety of unwanted phenomena. Haddon's pioneering work on countermeasures has had a major influence on later thinking about safety. Considering its impact it is remarkable that the literature offers almost no discussions related to the theoretical foundations of Haddon's countermeasure strategies. The present report addresses a number of theoretical issues related to Haddon's countermeasure strategies, which are: 1) A reformulation and formalization of Haddon's countermeasure strategies. 2) An identification and description of some of the problems associated with the term 'barrier'. 3) Suggestions for a more precise terminology based on the causal structure of countermeasures. 4) Extending the scope of countermeasures to include sign-based countermeasures. (au)


    Directory of Open Access Journals (Sweden)

    Vladislav M. Sannikov


    Full Text Available General barriers of organization of different types of strategic alliances have beenconsidered in the article. There are several recommendations for overcoming themin cases of international alliances, and in case of work in one state. The article also identified goals and tasks of single coordination center of alliance to overcome organization barriers.

  18. Interleukin-1β induces blood-brain barrier disruption by downregulating Sonic hedgehog in astrocytes.

    Directory of Open Access Journals (Sweden)

    Yue Wang

    Full Text Available The blood-brain barrier (BBB is composed of capillary endothelial cells, pericytes, and perivascular astrocytes, which regulate central nervous system homeostasis. Sonic hedgehog (SHH released from astrocytes plays an important role in the maintenance of BBB integrity. BBB disruption and microglial activation are common pathological features of various neurologic diseases such as multiple sclerosis, Parkinson's disease, amyotrophic lateral sclerosis, and Alzheimer's disease. Interleukin-1β (IL-1β, a major pro-inflammatory cytokine released from activated microglia, increases BBB permeability. Here we show that IL-1β abolishes the protective effect of astrocytes on BBB integrity by suppressing astrocytic SHH production. Astrocyte conditioned media, SHH, or SHH signal agonist strengthened BBB integrity by upregulating tight junction proteins, whereas SHH signal inhibitor abrogated these effects. Moreover, IL-1β increased astrocytic production of pro-inflammatory chemokines such as CCL2, CCL20, and CXCL2, which induce immune cell migration and exacerbate BBB disruption and neuroinflammation. Our findings suggest that astrocytic SHH is a potential therapeutic target that could be used to restore disrupted BBB in patients with neurologic diseases.

  19. Magnetic Resonance Imaging to Assess Blood–Brain Barrier Damage in Murine Trypanosomiasis (United States)

    Rodgers, Jean; McCabe, Christopher; Gettinby, George; Bradley, Barbara; Condon, Barrie; Kennedy, Peter G. E.


    The ability of trypanosomes to invade the brain and induce an inflammatory reaction is well-recognized. This study uses magnetic resonance imaging (MRI) in conjunction with a murine model of central nervous system (CNS) stage trypanosomiasis to investigate this phenomenon at the level of the blood–brain barrier (BBB). Mice were scanned before and after administration of the contrast agent. Signal enhancement maps were generated, and the percentage signal change was calculated. The severity of the neuroinflammation was also assessed. Statistical analysis of the signal change data revealed a significantly (P = 0.028) higher signal enhancement in mice at 28 days post-infection (least squares mean = 26.709) compared with uninfected animals (6.298), indicating the presence of BBB impairment. Leukocytes were found in the meninges and perivascular space of some blood vessels in the infected mice. This study shows that the integrity of the BBB is compromised during CNS stage trypanosomiasis and that the impairment does not correlate with inflammatory cell infiltration. PMID:21292912

  20. The amount of C1q-adiponectin complex is higher in the serum and the complex localizes to perivascular areas of fat tissues and the intimal-medial layer of blood vessels of coronary artery disease patients. (United States)

    Hong, Eun Shil; Lim, Cheong; Choi, Hye Yeon; Ku, Eu Jeong; Kim, Kyoung Min; Moon, Jae Hoon; Lim, Soo; Park, Kyong Soo; Jang, Hak Chul; Choi, Sung Hee


    The complement component C1q triggers activation of the classical immune pathway and can bind to adiponectin (APN). Recently, some studies have been reported that serum C1q-APN/total APN ratio correlates with atherosclerosis and coronary artery disease (CAD). We assessed the relationships between C1q related variables and the severity of CAD, and investigated the localization of the C1q-APN complex. The sample included 153 subjects comprising healthy controls and patients with subclinical or overt CAD. We measured the serum concentrations of C1q, total APN, and high-molecular weight (HMW)-APN, and the amount of C1q-APN complex. We identified the sites of C1q-APN complex deposition in various adipose tissues and blood vessels. Serum concentrations of C1q and HMW-APN and the C1q/HMW-APN ratio were independently associated with the severity of coronary stenosis. The amount of C1q-APN complex was significantly higher in patients with CAD compared with controls. C1q and APN co-localized in perivascular areas of subcutaneous, visceral, and pericardial fat tissues, and the internal mammary artery of patients with severe CAD. Serum C1q concentration and the C1q/HMW-APN ratio were independent markers of coronary artery stenosis. The amount of C1q-APN complex was significantly greater in serum from CAD patients. C1q and APN co-localized to perivascular areas in adipose tissue and blood vessels. The association between the increased amount of the C1q-APN complex and CAD should be investigated further.

  1. Epistemological barriers to radical behaviorism. (United States)

    O'Donohue, W T; Callaghan, G M; Ruckstuhl, L E


    The historian and philosopher of science Gaston Bachelard proposed the concept of epistemological barriers to describe the intellectual challenges encountered by scientists in their work. In order to embrace novel ways of approaching a problem in science, scientists must overcome barriers or obstacles posed by their prior views. For example, Einsteinian physics presents scientists with claims that space is curved and that time and space are on the same continuum. We utilize Bachelard's concept of epistemological barriers to describe the differences between the intellectual journeys students pursuing advanced studies face when attempting to accept cognitive psychology or radical behaviorism. We contend that the folk psychological beliefs that students typically hold when entering these studies pose less challenge to cognitive psychology than to radical behaviorism. We also suggest that these barriers may also partly be involved in the problematic exegesis that has plagued radical behaviorism. In close, we offer some suggestions for dealing with these epistemological barriers.

  2. Functional consequences of neuromyelitis optica-IgG astrocyte interactions on blood-brain barrier permeability and granulocyte recruitment. (United States)

    Vincent, Thierry; Saikali, Philippe; Cayrol, Romain; Roth, Alejandro D; Bar-Or, Amit; Prat, Alexandre; Antel, Jack P


    Autoantibody neuromyelitis optica-IgG (NMO-IgG) recognizing aquaporin-4 (AQP4) is implicated as playing a central role in the physiopathology of NMO. The aim of this in vitro-based study was to characterize functional consequences of interaction between NMO-IgG and cells of the neurovascular unit (astrocytes and brain endothelium) that would provide insight into recognized features of NMO, namely altered blood-brain barrier (BBB) permeability and granulocyte recruitment. We used sera from NMO and longitudinally extensive transverse myelitis cases shown to bind in a characteristic perivascular pattern to primate cerebellar slices. Using flow cytometry, we found that sera from NMO-IgG-positive patients reacted with CNS-derived human fetal astrocytes, whereas sera from multiple sclerosis patients did not. We demonstrated that NMO-IgG binding to astrocytes alters aquaporin-4 polarized expression and increases permeability of a human BBB endothelium/astrocyte barrier. We further demonstrated that NMO-IgG binding to human fetal astrocytes can result in NK cell degranulation, astrocyte killing by Ab-dependent cellular cytotoxicity and complement-dependent granulocyte attraction through the BBB model. Our study highlights important functional roles for NMO-IgG that could account for pathological lesions and BBB dysfunction observed in NMO.

  3. Development of engineered barrier

    Energy Technology Data Exchange (ETDEWEB)

    Chun, Kwan Sik; Cho, Won Jin; Lee, Jae Owan; Kim, Seung Soo; Kang, Mu Ja


    Engineered barrier development was carried out into the three research fields : waste form, disposal container, and buffer. The waste form field dealt with long-term leaching tests with borosilicate waste glasses surrounded by compacted bentonite. The leach rate decreased with increasing time, and was higher for the waste specimen rich in U and Na. In the container field, preliminary concepts of disposal containers were recommended by conducting structural analysis, thermal analysis, and shielding analysis, and major properties of stainless steel, copper, and titanium as a container material were surveyed. The sensitization degrees of SUS 316 and316L were lower than those of SUS 304 and 304L, respectively. The crevice corrosion of sensitized stainless steel was sensitive to the content of salt. Researches into the buffer included establishment of its performance criteria followed by investigating major properties of buffer using potential material in Korea. Experiments were made for measuring hydraulic conductivities, swelling properties, mechanical properties, thermal conductivities, pore-water chemistry properties, and adsorption properties was also investigated. (author)

  4. Barriers to organic milk production

    Directory of Open Access Journals (Sweden)

    Jiří Duda


    Full Text Available This paper describes barriers to production of the organic milk. There was conducted a survey among conventional producers of cow’s milk. Based on the identified barriers to organic milk production and farmers’ opinions on them there were identified the most important barriers. The most important barrier to the production of organic milk in Vysočina region is considered to be the lack of price premiums for organic milk produced. The price premium is currently around 0.40 CZK per litre of organic milk. Farmers require a minimum price premium 1 CZK per litre, respectively 30 % increase of the price of milk. The higher price premium may serve as a motivation, which could eliminate the second major barrier - satisfaction with the current production. Problematic contact with suppliers has been identified as the third most important barrier by surveyed firms. Buyers do not respect the agreed purchase price (premium price. Partial barrier to organic milk production, according to surveyed farmers is the lack of the necessary amount of concentrated feed in the quality of organic milk.

  5. Australia's Great Barrier Reef (United States)


    The Great Barrier Reef extends for 2,000 kilometers along the northeastern coast of Australia. It is not a single reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by the MISR instrument on August 26, 2000 (Terra orbit 3679), and shows part of the southern portion of the reef adjacent to the central Queensland coast. The width of the MISR swath is approximately 380 kilometers, with the reef clearly visible up to approximately 200 kilometers from the coast. It may be difficult to see the myriad details in the browse image, but if you retrieve the higher resolution version, a zoomed display reveals the spectacular structure of the many reefs.The more northerly coastal area in this image shows the vast extent of sugar cane cultivation, this being the largest sugar producing area in Australia, centered on the city of Mackay. Other industries in the area include coal, cattle, dairying, timber, grain, seafood, and fruit. The large island off the most northerly part of the coast visible in this image is Whitsunday Island, with smaller islands and reefs extending southeast, parallel to the coast. These include some of the better known resort islands such as Hayman, Lindeman, Hamilton, and Brampton Islands.Further south, just inland of the small semicircular bay near the right of the image, is Rockhampton, the largest city along the central Queensland coast, and the regional center for much of central Queensland. Rockhampton is just north of the Tropic of Capricorn. Its hinterland is a rich pastoral, agricultural, and mining region.MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  6. Nature of "superluminal" barrier tunneling. (United States)

    Winful, Herbert G


    We show that the distortionless tunneling of electromagnetic pulses through a barrier is a quasistatic process in which the slowly varying envelope of the incident pulse modulates the amplitude of a standing wave. For pulses longer than the barrier width, the barrier acts as a lumped element with respect to the pulse envelope. The envelopes of the transmitted and reflected fields can adiabatically follow the incident pulse with only a small delay that originates from energy storage. The theory presented here provides a physical explanation of the tunneling process and resolves the mystery of apparent superluminality.

  7. Complexing-precipitating geochemical barriers (United States)

    Savenko, A. V.


    New types of geochemical barriers on which chemical elements are immobilized as a result of combined complex formation and precipitation of barely soluble mineral phases are examined. A significant concentration of major components (Fe, Al) forming more stable complexes than an immobilized component X in the material is a necessary condition for this type of geochemical barriers. Filtration of the solution through a geochemical barrier is accompanied by substitution of X in the complex with a major component. As a result, the activity of X in the free state increases, and one barely soluble mineral phase or another of the component X precipitates when the state of saturation is achieved.

  8. Skin Barrier Function and Allergens

    DEFF Research Database (Denmark)

    Engebretsen, Kristiane Aasen; Thyssen, Jacob Pontoppidan


    The skin is an important barrier protecting us from mechanical insults, microorganisms, chemicals and allergens, but, importantly, also reducing water loss. A common hallmark for many dermatoses is a compromised skin barrier function, and one could suspect an elevated risk of contact sensitization...... and skin barrier status. Psoriasis has traditionally been regarded a Th1-dominated disease, but the discovery of Th17 cells and IL-17 provides new and interesting information regarding the pathogenesis of the disease. Research suggests an inverse relationship between psoriasis and CA, possibly due...

  9. Translating barriers into potential improvements

    DEFF Research Database (Denmark)

    Altintzoglou, Themistoklis; Hansen, Karina Birch; Valsdottir, Thora


    Purpose: The aim of this study is to explore potential barriers to seafood consumption by The aim of this study is to explore potential barriers to seafood consumption by young adults and the parents of young children. Knowledge of these barriers will be used to assist the development of new...... about the amount of effort required to prepare it. These concerns resulted in an expression of their need for products that are attractive, healthy, palatable, and convenient. In particular, the newly developed products should be accompanied by clear advice on preparation methods and materials...

  10. Coastal Structures and Barriers 2012 (United States)

    California Department of Resources — This dataset is a compilation of the UCSC Sand Retention Structures, MC Barriers, and USACE Coastal Structures. UCSC Sand Retention Structures originate from a...

  11. Barrier creams: facts and controversies. (United States)

    Corazza, Monica; Minghetti, Sara; Bianchi, Anna; Virgili, Annarosa; Borghi, Alessandro


    Barrier creams (BCs) represent devices aiming to protect the skin from contact with exogenous hazardous substances, especially under working conditions. By preventing penetration and absorption of contaminants, BCs are designed to reduce the risk of developing both irritant and allergic contact dermatitis. In fact, BCs should improve stratum corneum hydration as well as provide emolliency to maintain skin integrity and to restore and repair the epidermis barrier function. The formulation and ingredients of the available BCs vary widely, and thus the choice of a BC should depend on the kind of contaminants, occupational conditions, and skin dysfunction. Although BCs are commonly recommended to prevent occupational contact dermatitis, their real benefit remains controversial. The aims of this review are to help the choice of appropriate BCs and to analyze the actual effectiveness in maintaining an intact skin barrier, preventing contact dermatitis, and speeding up the healing of barrier-impaired skin.

  12. Great Barrier Reef, Queensland, Australia (United States)


    This detailed view of the Great Barrier Reef, Queensland, Australia (19.5S, 149.5E) shows several small patch reefs within the overall reef system. The Great Barrier Reef, largest in the world, comprises thousands of individual reefs of great variety and are closely monitored by marine ecologists. These reefs are about 6000 years old and sit on top of much older reefs. The most rapid coral growth occurs on the landward side of the reefs.

  13. Superheavy nuclei and fission barriers (United States)

    Lu, Bing-Nan; Zhao, Jie; Zhao, En-Guang; Zhou, Shan-Gui

    In this chapter, we will present relativistic mean field (RMF) description of heavy and superheavy nuclei (SHN). We will discuss the shell structure and magic numbers in the mass region of SHN, binding energies and α decay Q values, shapes of ground states and potential energy surfaces and fission barriers. We particularly focus on the multidimensionally-constrained covariant density functional theories (CDFT) and the applications of CDFT to the study of exotic nuclear shapes and fission barriers.

  14. Global interrupt and barrier networks (United States)

    Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E; Heidelberger, Philip; Kopcsay, Gerard V.; Steinmacher-Burow, Burkhard D.; Takken, Todd E.


    A system and method for generating global asynchronous signals in a computing structure. Particularly, a global interrupt and barrier network is implemented that implements logic for generating global interrupt and barrier signals for controlling global asynchronous operations performed by processing elements at selected processing nodes of a computing structure in accordance with a processing algorithm; and includes the physical interconnecting of the processing nodes for communicating the global interrupt and barrier signals to the elements via low-latency paths. The global asynchronous signals respectively initiate interrupt and barrier operations at the processing nodes at times selected for optimizing performance of the processing algorithms. In one embodiment, the global interrupt and barrier network is implemented in a scalable, massively parallel supercomputing device structure comprising a plurality of processing nodes interconnected by multiple independent networks, with each node including one or more processing elements for performing computation or communication activity as required when performing parallel algorithm operations. One multiple independent network includes a global tree network for enabling high-speed global tree communications among global tree network nodes or sub-trees thereof. The global interrupt and barrier network may operate in parallel with the global tree network for providing global asynchronous sideband signals.

  15. Economic alternatives for containment barriers

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, P.J.; Jasperse, B.H.; Fisher, M.J. [Geo-Con, Inc., Monroeville, PA (United States)


    Fixation, barriers, and containment of existing landfills and other disposal areas are often performed by insitu auger type soil mixing and jet grouting. Cement or other chemical reagents are mixed with soil to form both vertical and horizontal barriers. Immobilization of contaminants can be economically achieved by mixing soil and the contaminants with reagents that solidify or stabilize the contaminated area. Developed in Japan, and relatively new to the United States, the first large scale application was for a vertical barrier at the Jackson Lake Dam project in 1986. This technology has grown in both the civil and environmental field since. The paper describes current United States practice for Deep Soil Mixing (over 12 meters in depth), and Shallow Soil Mixing for vertical barriers and stabilization/solidification, and Jet Grouting for horizontal and vertical barriers. Creating very low permeability barriers at depth with minimal surface return often makes these techniques economical when compared to slurry trenches. The paper will discuss equipment, materials, soil and strength parameters, and quality control.

  16. Multimodal investigations of trans-endothelial cell trafficking under condition of disrupted blood-brain barrier integrity

    Directory of Open Access Journals (Sweden)

    Masaryk Thomas


    Full Text Available Abstract Background Stem cells or immune cells targeting the central nervous system (CNS bear significant promises for patients affected by CNS disorders. Brain or spinal cord delivery of therapeutic cells is limited by the blood-brain barrier (BBB which remains one of the recognized rate-limiting steps. Osmotic BBB disruption (BBBD has been shown to improve small molecule chemotherapy for brain tumors, but successful delivery of cells in conjunction with BBBD has never been reported. We have used a clinically relevant model (pig of BBBD to attempt brain delivery of TALL-104, a human leukemic T cell line. TALL-104 cells are potent tumor killers and have demonstrated potential for systemic tumor therapy. The pig model used is analogous to the clinical BBBD procedure. Cells were injected in the carotid artery after labeling with the MRI T1 contrast agent GdHPDO3A. Contrast CT scans were used to quantify BBBD and MRI was used to detect Gd++-loaded cells in the brain. Transcranial Doppler was used to monitor cerebral blood flow. EEG recordings were used to detect seizures. Immunocytochemical detection (Cresyl Violet, anti-human CD8 for TALL-104, Evans Blue for BBB damage, GFAP and NEUN was performed. Results At the concentration used TALL-104 cells were tolerated. Incomplete BBBD did not allow cell entry into the brain. MRI scans at 24 and 48 hours post-injection allowed visualization of topographically segregated cells in the hemisphere that underwent successful BBBD. Perivascular location of TALL-104 was confirmed in the BBBD hemisphere by Cresyl violet and CD8 immunocytochemistry. No significant alteration in CBF or EEG activity was recorded during cell injections. Conclusions Our data show that targeted CNS cell therapy requires blood-brain barrier disruption. MRI-detectable cytotoxic anti-neoplastic cells can be forced to transverse the BBB and accumulate in the perivascular space. The virtual absence of toxicity, the high anti-tumor activity

  17. Sulforaphane preconditioning of the Nrf2/HO-1 defense pathway protects the cerebral vasculature against blood-brain barrier disruption and neurological deficits in stroke. (United States)

    Alfieri, Alessio; Srivastava, Salil; Siow, Richard C M; Cash, Diana; Modo, Michel; Duchen, Michael R; Fraser, Paul A; Williams, Steven C R; Mann, Giovanni E


    Disruption of the blood-brain barrier (BBB) and cerebral edema are the major pathogenic mechanisms leading to neurological dysfunction and death after ischemic stroke. The brain protects itself against infarction via activation of endogenous antioxidant defense mechanisms, and we here report the first evidence that sulforaphane-mediated preactivation of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target heme oxygenase-1 (HO-1) in the cerebral vasculature protects the brain against stroke. To induce ischemic stroke, Sprague-Dawley rats were subjected to 70 min middle cerebral artery occlusion (MCAo) followed by 4, 24, or 72 h reperfusion. Nrf2 and HO-1 protein expression was upregulated in cerebral microvessels of peri-infarct regions after 4-72 h, with HO-1 preferentially associated with perivascular astrocytes rather than the cerebrovascular endothelium. In naïve rats, treatment with sulforaphane increased Nrf2 expression in cerebral microvessels after 24h. Upregulation of Nrf2 by sulforaphane treatment prior to transient MCAo (1h) was associated with increased HO-1 expression in perivascular astrocytes in peri-infarct regions and cerebral endothelium in the infarct core. BBB disruption, lesion progression, as analyzed by MRI, and neurological deficits were reduced by sulforaphane pretreatment. As sulforaphane pretreatment led to a moderate increase in peroxynitrite generation, we suggest that hormetic preconditioning underlies sulforaphane-mediated protection against stroke. In conclusion, we propose that pharmacological or dietary interventions aimed to precondition the brain via activation of the Nrf2 defense pathway in the cerebral microvasculature provide a novel therapeutic approach for preventing BBB breakdown and neurological dysfunction in stroke. Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.

  18. Diabetes and diet : managing dietary barriers

    NARCIS (Netherlands)

    Friele, R.D.


    This thesis reports on the barriers diabetic patients experience with their diet, and the ways they cope with these barriers. A dietary barrier is a hinderance to a person's well-being, induced by being advised a diet. First inventories were made of possible dietary barriers and ways of

  19. Bioenergetic Progress and Heat Barriers (United States)

    Zotin, A. A.; Lamprecht, I.; Zotin, A. I.


    Progressing biological evolution is discussed in the framework of nonequilibrium thermodynamics. It is connected with an increase of the mass specific standard metabolism given by coefficient a in the allometric relation (1) between oxygen consumption rate and body mass of an animal. Three “heat barriers” are found in the course of such a bioenergetic evolution. The first heat barrier concerns an animal's overheating during active movement and is overcome by the development of thermoregulation and the appearance of homeothermic animals. A second barrier arises when the coefficient a reaches values connected with lethal body temperatures. The transition across this second heat barrier occurs as result of reasonable activities and the appearance of civilization. The third heat barrier will arise during the further development of human civilization, connected with a highly increased energy production and a fatal warming of the Earth atmosphere. The manner to overcome this barrier will probably depend on the assimilation of space and the establishment of energy consuming industries outside the Earth. The bioenergetic evolution discussed in this paper does not exclude other trends of evolution, e.g. increase of size, and does not mean to be the only aspect of biological evolution.

  20. Barrier distributions from elastic scattering

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, N. [Manchester Univ. (United Kingdom). Dept. of Physics]|[Surrey Univ., Guildford (United Kingdom). Dept. of Physics; Timmers, H.; Leigh, J.R.; Masgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics


    A new representation of the distribution of potential barriers present in heavy ion reactions is defined in terms of the elastic scattering excitation function. Its validity is demonstrated for the systems {sup 16}0 + {sup 144,} {sup 154}Sm, {sup 186}W, {sup 208}Pb, for which precise measurements have been made. Compared with fusion barrier distributions, which show structures characteristic of collective inelastic couplings, the elastic distributions are less detailed. This appears to be due to couplings to weaker direct reaction channels. 20 refs., 3 figs.

  1. Communication barriers in the family

    Directory of Open Access Journals (Sweden)



    Full Text Available The art of communication – listening and speaking – is a major life skill, with a thorough influence on every human life. Remaining silent while the interlocutor speaks is not all that there is to the act of listening to messages. True listening is based on an intention to get involved in understanding of the other person, enjoying his or her presence, learning something from the conversation, giving assistance, or comforting the interlocutor. In the article the author describes obstacles (barriers, which render true listening impossible. These barriers have been identified by a group of young adults.

  2. Systems study on engineered barriers: barrier performance analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stula, R.T.; Albert, T.E.; Kirstein, B.E.; Lester, D.H.


    A performance assessment model for multiple barrier packages containing unreprocessed spent fuel has been modified and applied to several package designs. The objective of the study was to develop information to be used in programmatic decision making concerning engineered barrier package design and development. The assessment model, BARIER, was developed in previous tasks of the System Study on Engineered Barriers (SSEB). The new version discussed in this report contains a refined and expanded corrosion rate data base which includes pitting, crack growth, and graphitization as well as bulk corrosion. Corrosion rates for oxic and anoxic conditions at each of the two temperature ranges are supplied. Other improvements include a rigorous treatment of radionuclide release after package failure which includes resistance of damaged barriers and backfill, refined temperature calculations that account for convection and radiation, a subroutine to calculate nuclear gamma radiation field at each barrier surface, refined stress calculations with reduced conservatism and various coding improvements to improve running time and core usage. This report also contains discussion of alternative scenarios to the assumed flooded repository as well as the impact of water exclusion backfills. The model was used to assess post repository closure performance for several designs which were all variation of basic designs from the Spent Unreprocessed Fuel (SURF) program. Many designs were found to delay the onset of leaching by at least a few hundreds of years in all geologic media. Long delay times for radionuclide release were found for packages with a few inches of sorption backfill. Release of uranium, plutonium, and americium was assessed.

  3. Overcoming Barriers: Women in Superintendency (United States)

    Miller, Claire M.


    Women currently represent the largest number of teachers in the United States but remain underrepresented in the superintendent position. This suggests that the superintendency has been influenced by patriarchy. If women are to break through the barriers that prevent them from attaining a superintendency, we will need to understand the social…

  4. Functional barriers: Properties and evaluation

    NARCIS (Netherlands)

    Feigenbaum, A.; Dole, P.; Aucejo, S.; Dainelli, D.; Cruz Garcia, C. de la; Hankemeier, T.; N'Gono, Y.; Papaspyrides, C.D.; Paseiro, P.; Pastorelli, S.; Pavlidou, S.; Pennarun, P.Y.; Saillard, P.; Vidal, L.; Vitrac, O.; Voulzatis, Y.


    Functional barriers are multilayer structures deemed to prevent migration of some chemicals released by food-contact materials into food. In the area of plastics packaging, different migration behaviours of mono- and multilayer structures are assessed in terms of lag time and of their influence of

  5. Barrier/Cu contact resistivity

    Energy Technology Data Exchange (ETDEWEB)

    Reid, J.S.; Nicolet, M.A. [California Inst. of Tech., Pasadena, CA (United States); Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y. [Cornell Univ., Ithaca, NY (United States); Smith, P.M. [Sandia National Labs., Albuquerque, NM (United States)


    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  6. Official English: Bridge or Barrier? (United States)

    Krashen, Stephen


    Discusses the official English movement in the United States. Provides suggestions for groups that really want to help immigrants acquire English, by building bridges and not barriers. These include the following: (1) joining private and charitable organizations in helping make English-as-a-Second-Language classes available; (2) support libraries;…

  7. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    effects on the fusion excitation function. However, a simultaneous analysis of the fusion, elastic and quasi-elastic channels would fix the structure and the reaction unambiguously. Keywords. Heavy ion fusion; fusion barrier distributions; nuclear structure; coupled reaction chan- nel calculations. PACS Nos 25.70.Bc; 25.70.

  8. Structure information from fusion barriers

    Indian Academy of Sciences (India)

    The fusion excitation functions for 16O+208Pb, using the coupled reaction channel (CRC) method and correct structure information, have been analysed. The barrier distributions derived from these excitation functions including many of the significant channels are featureless, although these channels have considerable ...

  9. Communication Barriers in Distance Education (United States)

    Isman, Aytekin; Dabaj, Fahme; Altinay, Fahriye; Altinay, Zehra


    Communication is a key concept as being the major tool for people in order to satisfy their needs. It is an activity which refers as process and effective communication requires qualified communication with the elimination of communication barriers. As it is known, distance education is a new trend by following contemporary facilities and tools…

  10. FX barriers with smile dynamics

    NARCIS (Netherlands)

    Baker, Glyn; Beneder, Reimer; Zilber, A.


    Our mandate in this work has been to isolate the features of smile consistent models that are most relevant to the pricing of barrier options. We consider the two classical approaches of stochastic and (parametric) local volatility. Although neither has been particularly successful in practice their

  11. Reaction rates when barriers fluctuate


    Reimann, Peter


    Reaction rates when barriers fluctuate : a path integral approach / P. Hänggi and P. Reimann. - In: International Conference on Path Integrals from peV to TeV : Proceedings of the ... / eds.: R. Casalbuoni ... - Singapore u.a. : World Scientific, 1999. - S. 407-409

  12. Experimental chronic cerebral hypoperfusion results in decreased pericyte coverage and increased blood-brain barrier permeability in the corpus callosum. (United States)

    Liu, Qinghai; Radwanski, Ryan; Babadjouni, Robin; Patel, Arati; Hodis, Drew M; Baumbacher, Peter; Zhao, Zhen; Zlokovic, Berislav; Mack, William J


    Murine chronic cerebral hypoperfusion (CCH) results in white matter (WM) injury and behavioral deficits. Pericytes influence blood-brain barrier (BBB) integrity and cerebral blood flow. Under hypoxic conditions, pericytes detach from perivascular locations increasing vessel permeability and neuronal injury. This study characterizes the time course of BBB dysfunction and pericyte coverage following murine experimental CCH secondary to bilateral carotid artery stenosis (BCAS). Mice underwent BCAS or sham operation. On post-procedure days 1, 3, 7 and 30, corpus callosum BBB permeability was characterized using Evans blue (EB) extravasation and IgG staining and pericyte coverage/count was calculated. The BCAS cohort demonstrated increased EB extravasation on postoperative days 1 ( p = 0.003) 3 ( p = 0.002), and 7 ( p = 0.001) when compared to sham mice. Further, EB extravasation was significantly greater ( p = 0.05) at day 3 than at day 30 in BCAS mice. BCAS mice demonstrated a nadir in pericyte coverage and count on post-operative day 3 ( p < 0.05, compared to day 7, day 30 and sham). Decreased pericyte coverage/count and increased BBB permeability are most pronounced on postoperative day 3 following murine CCH. This precedes any notable WM injury or behavioral deficits.

  13. Altered permeability barrier structure in cholesteatoma matrix

    DEFF Research Database (Denmark)

    Svane-Knudsen, Viggo; Halkier-Sørensen, Lars; Rasmussen, Gurli


    lipid structures filling the intercellular spaces mainly control the barrier function. The barrier in cholesteatoma epithelium is several times thicker than in unaffected skin but presents distinctive features of a defective barrier as seen in other scaling skin diseases. The intercellular spaces appear...... frequently occur. The corneocytes are shed in clusters, not as single cells. Further, lipid droplets and intracellular membranous material are occasionally seen. In spite of these clear signs of barrier dysfunction, it is unknown whether the thickness of the barrier compensates for the defect in barrier...

  14. Postulated Role of Vasoactive Neuropeptide-Related Immunopathology of the Blood Brain Barrier and Virchow-Robin Spaces in the Aetiology of Neurological-Related Conditions

    Directory of Open Access Journals (Sweden)

    D. R. Staines


    Full Text Available Vasoactive neuropeptides (VNs such as pituitary adenylate cyclase-activating polypeptide (PACAP and vasoactive intestinal peptide (VIP have critical roles as neurotransmitters, vasodilators including perfusion and hypoxia regulators, as well as immune and nociception modulators. They have key roles in blood vessels in the central nervous system (CNS including maintaining functional integrity of the blood brain barrier (BBB and blood spinal barrier (BSB. VNs are potent activators of adenylate cyclase and thus also have a key role in cyclic AMP production affecting regulatory T cell and other immune functions. Virchow-Robin spaces (VRSs are perivascular compartments surrounding small vessels within the CNS and contain VNs. Autoimmunity of VNs or VN receptors may affect BBB and VRS function and, therefore, may contribute to the aetiology of neurological-related conditions including multiple sclerosis, Parkinson's disease, and amyotrophic lateral sclerosis. VN autoimmunity will likely affect CNS and immunological homeostasis. Various pharmacological and immunological treatments including phosphodiesterase inhibitors and plasmapheresis may be indicated.

  15. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.


    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the ``barriers`` literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  16. Barriers to improvements in energy efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, A.K.N.


    To promote energy-efficiency improvements, actions may be required at one or more levels -- from the lowest level of the consumer (residential, commercial, industrial, etc.) through the highest level of the global agencies. But barriers to the implementation of energy-efficiency improvements exist or can arise at all these levels. Taking up each one of these barriers in turn, the paper discusses specific measures that can contribute to overcoming the barriers. However, a one-barrier-one-measure approach must be avoided. Single barriers may in fact involve several sub-barriers. Also, combinations of measures are much more effective in overcoming barriers. In particular, combinations of measures that simultaneously overcome several barriers are most successful. The paper discusses the typology of barriers, explores their origin and suggests measures that by themselves or in combination with other measures, will overcome these barriers. Since most of the barriers dealt with can be found in the barriers'' literature, any originality in the paper lies in its systematic organization, synoptic view and holistic treatment of this issue. This paper is intended to initiate a comprehensive treatment of barriers, their origins and the measures that contribute to overcoming them. Hopefully, such a treatment will facilitate the implementation of energy-efficiency improvements involving a wide diversity of ever-changing energy end uses and consumer preferences.

  17. Patient advocacy: barriers and facilitators

    Directory of Open Access Journals (Sweden)

    Nikravesh Mansoure


    Full Text Available Abstract Background During the two recent decades, advocacy has been a topic of much debate in the nursing profession. Although advocacy has embraced a crucial role for nurses, its extent is often limited in practice. While a variety of studies have been generated all over the world, barriers and facilitators in the patient advocacy have not been completely identified. This article presents the findings of a study exploring the barriers and facilitators influencing the role of advocacy among Iranian nurses. Method This study was conducted by grounded theory method. Participants were 24 Iranian registered nurses working in a large university hospital in Tehran, Iran. Semi-structured interviews were used for data collection. All interviews were transcribed verbatim and simultaneously Constant comparative analysis was used according to the Strauss and Corbin method. Results Through data analysis, several main themes emerged to describe the factors that hindered or facilitated patient advocacy. Nurses in this study identified powerlessness, lack of support, law, code of ethics and motivation, limited communication, physicians leading, risk of advocacy, royalty to peers, and insufficient time to interact with patients and families as barriers to advocacy. As for factors that facilitated nurses to act as a patient advocate, it was found that the nature of nurse-patient relationship, recognizing patients' needs, nurses' responsibility, physician as a colleague, and nurses' knowledge and skills could be influential in adopting the advocacy role. Conclusion Participants believed that in this context taking an advocacy role is difficult for nurses due to the barriers mentioned. Therefore, they make decisions and act as a patient's advocate in any situation concerning patient needs and status of barriers and facilitators. In most cases, they can not act at an optimal level; instead they accept only what they can do, which we called 'limited advocacy' in

  18. Application of Texture Analysis to Study Small Vessel Disease and Blood–Brain Barrier Integrity

    Directory of Open Access Journals (Sweden)

    Maria del C. Valdés Hernández


    Full Text Available ObjectivesWe evaluate the alternative use of texture analysis for evaluating the role of blood–brain barrier (BBB in small vessel disease (SVD.MethodsWe used brain magnetic resonance imaging from 204 stroke patients, acquired before and 20 min after intravenous gadolinium administration. We segmented tissues, white matter hyperintensities (WMH and applied validated visual scores. We measured textural features in all tissues pre- and post-contrast and used ANCOVA to evaluate the effect of SVD indicators on the pre-/post-contrast change, Kruskal–Wallis for significance between patient groups and linear mixed models for pre-/post-contrast variations in cerebrospinal fluid (CSF with Fazekas scores.ResultsTextural “homogeneity” increase in normal tissues with higher presence of SVD indicators was consistently more overt than in abnormal tissues. Textural “homogeneity” increased with age, basal ganglia perivascular spaces scores (p < 0.01 and SVD scores (p < 0.05 and was significantly higher in hypertensive patients (p < 0.002 and lacunar stroke (p = 0.04. Hypertension (74% patients, WMH load (median = 1.5 ± 1.6% of intracranial volume, and age (mean = 65.6 years, SD = 11.3 predicted the pre/post-contrast change in normal white matter, WMH, and index stroke lesion. CSF signal increased with increasing SVD post-contrast.ConclusionA consistent general pattern of increasing textural “homogeneity” with increasing SVD and post-contrast change in CSF with increasing WMH suggest that texture analysis may be useful for the study of BBB integrity.

  19. Analgesia pós-operatória em cirurgia ortopédica: estudo comparativo entre o bloqueio do plexo lombar por via perivascular inguinal (3 em 1 com ropivacaína e a analgesia subaracnóidea com morfina Analgesia pós-operatoria en cirugía ortopédica: estudio comparativo entre el bloqueo del plexo lombar por vía perivascular inguinal (3 en 1 con ropivacaína y la analgesia subaracnóidea con morfina Postoperative analgesia following orthopedic surgery: a study comparing perivascular lumbar plexus inguinal block with ropivacaine (3 in 1 and spinal anesthesia with morphine

    Directory of Open Access Journals (Sweden)

    Neuber Martins Fonseca


    Full Text Available JUSTIFICATIVA E OBJETIVOS: O bloqueio do plexo lombar pelo acesso perivascular inguinal, chamado de bloqueio 3 em 1, tem sido utilizado para analgesia pós-operatória. O objetivo deste estudo foi comparar a analgesia pós-operatória do bloqueio 3 em 1 a da morfina subaracnóidea em pacientes submetidos a cirurgias ortopédicas em membro inferior (MI. MÉTODO: Foram estudados 40 pacientes escalados para cirurgia ortopédica de MI, de ambos os sexos, estado físico ASA I e II, com idades entre 15 e 75 anos, distribuídos em 2 grupos (M e BPL. Foi realizada anestesia subaracnóidea em todos os pacientes, em L3-L4 ou L4-L5, com 20 mg de bupivacaína isobárica a 0,5%. No grupo M (n = 20 foi associado 50 µg de morfina ao anestésico local. No grupo BPL (n = 20 foi realizado o bloqueio 3 em 1 ao término da cirurgia, utilizando 200 mg de ropivacaína a 0,5%. Avaliou-se a analgesia e a intensidade da dor às 4, 8, 12, 14, 16, 20 e 24 horas após o término da cirurgia, o nível do bloqueio subaracnóideo, o tempo cirúrgico e as complicações. RESULTADOS: A duração da analgesia no grupo BPL foi de 13,1 ± 2,47, enquanto no grupo M todos os pacientes referiam dor e ausência de bloqueio motor no primeiro instante avaliado (4 horas. Houve falha do bloqueio de um dos 3 nervos em 3 pacientes. A incidência de náusea e prurido foi significativamente maior no grupo M. Quanto à retenção urinária, não houve diferença significante entre os grupos. Não houve depressão respiratória, hipotensão arterial ou bradicardia. A analgesia pós-operatória foi mais efetiva no grupo BPL, comparada ao grupo M às 4, 8, 12,14 e 16 horas. Às 20 e 24 horas não houve diferença significante entre os grupos. CONCLUSÕES: A analgesia pós-operatória proporcionada pelo bloqueio 3 em 1 apresentou efeitos colaterais inferiores à morfina subaracnóidea com tempo de analgesia semelhante.JUSTIFICATIVA Y OBJETIVOS: El bloqueo del plexo lumbar por el acceso

  20. Sports participation after rehabilitation : Barriers and facilitators

    NARCIS (Netherlands)

    Jaarsma, Eva A; Dekker, Rienk; Geertzen, Jan H.B.; Dijkstra, Pieter

    Objective: To analyse barriers to, and facilitators of, sports participation among people with physical disabilities after rehabilitation and to compare differences between inactive and active participants regarding these experienced barriers and facilitators. Methods: Participants were 1,223 adults

  1. Highway renewable energy : photovoltaic noise barriers (United States)


    Highway photovoltaic noise barriers (PVNBs) represent the combination of noise barrier systems and photovoltaic systems in order to mitigate traffic noise while simultaneously producing renewable energy. First deployed in Switzerland in 1989, PVNBs a...

  2. Security barriers with automated reconnaissance (United States)

    McLaughlin, James O; Baird, Adam D; Tullis, Barclay J; Nolte, Roger Allen


    An intrusion delaying barrier includes primary and secondary physical structures and can be instrumented with multiple sensors incorporated into an electronic monitoring and alarm system. Such an instrumented intrusion delaying barrier may be used as a perimeter intrusion defense and assessment system (PIDAS). Problems with not providing effective delay to breaches by intentional intruders and/or terrorists who would otherwise evade detection are solved by attaching the secondary structures to the primary structure, and attaching at least some of the sensors to the secondary structures. By having multiple sensors of various types physically interconnected serves to enable sensors on different parts of the overall structure to respond to common disturbances and thereby provide effective corroboration that a disturbance is not merely a nuisance or false alarm. Use of a machine learning network such as a neural network exploits such corroboration.

  3. Flexible pile thermal barrier insulator (United States)

    Anderson, G. E.; Fell, D. M.; Tesinsky, J. S. (Inventor)


    A flexible pile thermal barrier insulator included a plurality of upstanding pile yarns. A generally planar backing section supported the upstanding pile yarns. The backing section included a plurality of filler yarns forming a mesh in a first direction. A plurality of warp yarns were looped around said filler yarns and pile yarns in the backing section and formed a mesh in a second direction. A binder prevented separation of the yarns in the backing section.

  4. Article Including Environmental Barrier Coating System (United States)

    Lee, Kang N. (Inventor)


    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  5. Market barriers to welfare product innovations

    NARCIS (Netherlands)

    Binnekamp, M.H.A.; Ingenbleek, P.T.M.


    New products that are based on higher animal welfare standards encounter several barriers on the road to market acceptance. The authors focus on the Dutch poultry sector and distinguish between retailer and consumer barriers. Retailer barriers include the powerful position of retailers, the price

  6. The Barriers and Needs of Online Learners (United States)

    Srichanyachon, Napaporn


    This study investigated some specific barriers and needs that online students are facing when learning English through WebEx system. It compared students' barriers and needs with their background including gender, computer ownership, and monthly allowance. It also investigated the relationship among computer aptitude, barriers and needs of online…

  7. Design of the Muong Chuoi Barrier

    NARCIS (Netherlands)

    Van Vliegen, K.; Van Oorschot, N.; Meinen, N.; Van Dijk, S.; Reimert, Z.


    Ho Chi Minh City has to deal with severe flooding in the rainy season. To prevent the city from this flooding, MARD set up plan 1547. The main idea of the plan is to build a ring dike around HCMC in combination with several movable tidal barriers. One of these barriers is the Muong Chuoi Barrier.

  8. Postulated vasoactive neuropeptide immunopathology affecting the blood–brain/blood–spinal barrier in certain neuropsychiatric fatigue-related conditions: A role for phosphodiesterase inhibitors in treatment?

    Directory of Open Access Journals (Sweden)

    Sonya Marshall-Gradisnik


    Full Text Available Donald R Staines1,2, Ekua W Brenu2, Sonya Marshall-Gradisnik21Queensland Health, Gold Coast Population Health Unit, Southport, Gold Coast, Queensland, Australia; 2Faculty of Health Science and Medicine, Population Health and Neuroimmunology Unit, Bond University, Robina, Queensland, AustraliaAbstract: Neuropsychiatric symptoms occur in a number of neurological fatigue-related conditions including multiple sclerosis (MS, Parkinson’s disease (PD, amyotrophic lateral sclerosis (ALS, and chronic fatigue syndrome (CFS. These conditions have been attributed variably to neuroinflammatory and neurodegenerative processes. While autoimmune pathology, at least in part, has long been suspected in these conditions proof has been elusive. Autoimmune pathomechanisms affecting the blood–brain barrier (BBB or blood–spinal barrier (BSB may predispose the BBB/BSB to ‘leakiness’ and be a precursor to additional autoimmune events resulting in neuroinflammatory or neurodegenerative processes. The aim of the paper is to postulate immunopathology of the cerebrospinal perivascular compartment involving certain vasoactive neuropeptides, specifically pituitary adenylate cyclase-activating polypeptide (PACAP and vasoactive intestinal peptide (VIP, in the etiology of certain neuropsychiatric fatigue-related conditions such as MS, ALS, PD, and CFS. Vasoactive neuropeptides (VNs such as PACAP and VIP have critical roles as neurotransmitters, vasodilators including perfusion and hypoxia regulators, and immune and nociception modulators. PACAP and VIP are widely distributed in the central nervous system (CNS and have key roles in CNS blood vessels including maintaining functional integrity of the BBB and BSB. Autoimmunity affecting these VNs would likely have a detrimental effect on BBB and BSB functioning arguably predisposing to further pathological processes. Virchow–Robin spaces (VRS are perivascular compartments surrounding small vessels within the CNS which

  9. Analgesia pós-operatória para procedimentos cirúrgicos ortopédicos de quadril e fêmur: comparação entre bloqueio do compartimento do psoas e bloqueio perivascular inguinal Analgesia postoperatoria para procedimientos quirúrgicos ortopédicos de cadera y fémur: comparación entre bloqueo del compartimiento del psoas y bloqueo perivascular inguinal Postoperative analgesia for orthopedic surgeries of the hip and femur: a comparison between psoas compartment and inguinal paravascular blocks

    Directory of Open Access Journals (Sweden)

    Luiz Eduardo Imbelloni


    Full Text Available JUSTIFICATIVA E OBJETIVOS: Este estudo avaliou a eficácia da injeção única de bupivacaína a 0,25% no compartimento do psoas ou perivascular inguinal por meio do estimulador de nervos periféricos para analgesia pós-operatória em pacientes submetidos a intervenções cirúrgicas ortopédicas. MÉTODO: Cem pacientes receberam bloqueio do plexo lombar através do compartimento do psoas e foram comparados com 100 pacientes que receberam bloqueio do plexo lombar via perivascular inguinal, identificados pelo estimulador de nervos periféricos com a injeção de 40 mL bupivacaína a 0,25% sem epinefrina. A analgesia nos nervos ilioinguinal, genitofemoral, cutâneo femoral lateral, femoral e obturatório foi avaliada 4, 8, 12, 16, 20 e 24 horas após o final da intervenção cirúrgica. A intensidade da dor foi também avaliada no mesmo período. A quantidade de opióides administrada no pós-operatório foi anotada. Em cinco pacientes de cada grupo, estudo radiográfico com contraste não-iônico foi realizado para avaliar a dispersão da solução anestésica. RESULTADOS: Os nervos ilioinguinal, genitofemoral, cutâneo femoral lateral, femoral e obturatório foram bloqueados em 92% dos pacientes no compartimento do psoas versus 62% no bloqueio perivascular inguinal. O bloqueio do plexo lombar reduziu a necessidade de opióides e 42% dos pacientes submetidos ao bloqueio do compartimento do psoas e 36% dos pacientes no bloqueio inguinal não necessitaram de analgésico adicional no pós-operatório. A duração da analgesia foi em torno de 21 horas com bloqueio do compartimento do psoas e 15 horas com bloqueio perivascular inguinal. CONCLUSÕES: O bloqueio do compartimento do psoas e perivascular inguinal é uma excelente técnica para analgesia pós-operatória em intervenções cirúrgicas ortopédicas reduzindo a necessidade de opióides. Este estudo mostrou que a injeção no compartimento do psoas foi mais fácil e mais efetiva no bloqueio

  10. Double barrier system for an in situ conversion process

    Energy Technology Data Exchange (ETDEWEB)

    McKinzie, Billy John [Houston, TX; Vinegar, Harold J [Bellaire, TX; Cowan, Kenneth Michael [Sugar land, TX; Deeg, Wolfgang Friedrich Johann [Houston, TX; Wong, Sau-Wai [Rijswijk, NL


    A barrier system for a subsurface treatment area is described. The barrier system includes a first barrier formed around at least a portion of the subsurface treatment area. The first barrier is configured to inhibit fluid from exiting or entering the subsurface treatment area. A second barrier is formed around at least a portion of the first barrier. A separation space exists between the first barrier and the second barrier.

  11. Westinghouse thermal barrier coatings development

    Energy Technology Data Exchange (ETDEWEB)

    Goedjen, J.G.; Wagner, G. [Westinghouse Electric Corp., Orlando, FL (United States)


    Westinghouse, in conjunction with the Department of Energy and Oak Ridge National Laboratory, has embarked upon a program for the development of advanced thermal barrier coatings for industrial gas turbines. Development of thermal barrier coatings (TBC`s) for industrial gas turbines has relied heavily on the transfer of technology from the aerospace industry. Significant differences in the time/temperature/stress duty cycles exist between these two coating applications. Coating systems which perform well in aerospace applications may not been optimized to meet power generation performance requirements. This program will focus on development of TBC`s to meet the specific needs of power generation applications. The program is directed at developing a state-of-the-art coating system with a minimum coating life of 25,000 hours at service temperatures required to meet increasing operating efficiency goals. Westinghouse has assembled a team of university and industry leaders to accomplish this goal. Westinghouse will coordinate the efforts of all program participants. Chromalloy Turbine Technologies, Inc. and Sermatech International, Inc. will be responsible for bond coat and TBC deposition technology. Praxair Specialty Powders, Inc. will be responsible for the fabrication of all bond coat and ceramic powders for the program. Southwest Research Institute will head the life prediction modelling effort; they will also be involved in coordinating nondestructive evaluation (NDE) efforts. Process modelling will be provided by the University of Arizona.

  12. Barriers to Medical Error Reporting. (United States)

    Poorolajal, Jalal; Rezaie, Shirin; Aghighi, Negar


    This study was conducted to explore the prevalence of medical error underreporting and associated barriers. This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan, Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%), lack of proper reporting form (51.8%), lack of peer supporting a person who has committed an error (56.0%), and lack of personal attention to the importance of medical errors (62.9%). The rate of committing medical errors was higher in men (71.4%), age of 50-40 years (67.6%), less-experienced personnel (58.7%), educational level of MSc (87.5%), and staff of radiology department (88.9%). This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  13. Barriers to medical error reporting

    Directory of Open Access Journals (Sweden)

    Jalal Poorolajal


    Full Text Available Background: This study was conducted to explore the prevalence of medical error underreporting and associated barriers. Methods: This cross-sectional study was performed from September to December 2012. Five hospitals, affiliated with Hamadan University of Medical Sciences, in Hamedan,Iran were investigated. A self-administered questionnaire was used for data collection. Participants consisted of physicians, nurses, midwives, residents, interns, and staffs of radiology and laboratory departments. Results: Overall, 50.26% of subjects had committed but not reported medical errors. The main reasons mentioned for underreporting were lack of effective medical error reporting system (60.0%, lack of proper reporting form (51.8%, lack of peer supporting a person who has committed an error (56.0%, and lack of personal attention to the importance of medical errors (62.9%. The rate of committing medical errors was higher in men (71.4%, age of 50-40 years (67.6%, less-experienced personnel (58.7%, educational level of MSc (87.5%, and staff of radiology department (88.9%. Conclusions: This study outlined the main barriers to reporting medical errors and associated factors that may be helpful for healthcare organizations in improving medical error reporting as an essential component for patient safety enhancement.

  14. Overcoming Barriers in Unhealthy Settings

    Directory of Open Access Journals (Sweden)

    Michael K. Lemke


    Full Text Available We investigated the phenomenon of sustained health-supportive behaviors among long-haul commercial truck drivers, who belong to an occupational segment with extreme health disparities. With a focus on setting-level factors, this study sought to discover ways in which individuals exhibit resiliency while immersed in endemically obesogenic environments, as well as understand setting-level barriers to engaging in health-supportive behaviors. Using a transcendental phenomenological research design, 12 long-haul truck drivers who met screening criteria were selected using purposeful maximum sampling. Seven broad themes were identified: access to health resources, barriers to health behaviors, recommended alternative settings, constituents of health behavior, motivation for health behaviors, attitude toward health behaviors, and trucking culture. We suggest applying ecological theories of health behavior and settings approaches to improve driver health. We also propose the Integrative and Dynamic Healthy Commercial Driving (IDHCD paradigm, grounded in complexity science, as a new theoretical framework for improving driver health outcomes.

  15. Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Ping, E-mail: [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China); Kong, Feng; Wang, Jue [Central Laboratory, The Second Hospital of Shandong University, Shandong, Jinan 250033 (China); Lu, Qinghua [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China); Xu, Haijia [Department of Cardiology, Wendeng Central Hospital of Weihai City, Shandong, Weihai 264400 (China); Qi, Tonggang [Central Laboratory, The Second Hospital of Shandong University, Shandong, Jinan 250033 (China); Meng, Juan [Department of Cardiology, The Second Hospital of Shandong University, No. 247, Beiyuan Road, Shandong, Jinan 250033 (China)


    Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS expression

  16. Perivascular ancestors of adult multipotent stem cells

    NARCIS (Netherlands)

    M. Corselli (Mirko); C.W. Chen; M. Crisan (Mihaela); L. Lazzari (Lorenza); B. Péault (Bruno)


    textabstractIndependent studies by numerous investigators have shown that it is possible to harvest multipotent progenitor cells from diverse dissociated and cultured fetal, perinatal, and principally adult developed tissues. Despite the increasingly recognized medical value of these progenitor

  17. Mucus as a Barrier to Drug Delivery

    DEFF Research Database (Denmark)

    Bøgh, Marie; Nielsen, Hanne Mørck


    Viscoelastic mucus lines all mucosal surfaces of the body and forms a potential barrier to mucosal drug delivery. Mucus is mainly composed of water and mucins; high-molecular weight glycoproteins forming an entangled network. Consequently, mucus forms a steric barrier and due to its negative charge...... and hydrophobic domains, the overall hydrophilic mucus also presents an interactive barrier limiting the free diffusion of components within and through the mucus. Furthermore, mucus is a dynamic barrier due to its continuous secretion and shedding from the mucosal surfaces. Mucus is thus a highly complex gel...... barrier to drug delivery. Current knowledge of mucus characteristics and barrier properties, as achieved by state-of-the-art methodologies, is the topic of this MiniReview emphasizing the gastrointestinal mucus and an overall focus on oral drug delivery. Cell culture-based in vitro models are well...

  18. Barrier experiment: Shock initiation under complex loading

    Energy Technology Data Exchange (ETDEWEB)

    Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The barrier experiments are a variant of the gap test; a detonation wave in a donor HE impacts a barrier and drives a shock wave into an acceptor HE. The question we ask is: What is the trade-off between the barrier material and threshold barrier thickness to prevent the acceptor from detonating. This can be viewed from the perspective of shock initiation of the acceptor subject to a complex pressure drive condition. Here we consider key factors which affect whether or not the acceptor undergoes a shock-to-detonation transition. These include the following: shock impedance matches for the donor detonation wave into the barrier and then the barrier shock into the acceptor, the pressure gradient behind the donor detonation wave, and the curvature of detonation front in the donor. Numerical simulations are used to illustrate how these factors affect the reaction in the acceptor.

  19. Storm impacts on small barrier islands

    DEFF Research Database (Denmark)

    Kroon, Aart; Fruergaard, Mikkel

    water levels. These storms induce collision, overwash or inundation of the barrier crest and generate wash-over fans and barrier breaching. In this presentation, we focus on the present-day morphologic evolution of these barrier islands, couple these to extreme events, and we will predict the potential......The shorelines of the Baltic Sea and the inner coastal waters in Denmark consist of many barrier islands. These sandy barrier islands were mainly formed in the Holocene and are still very dynamic. The present day changes in the morphology are dominantly governed by storm waves and associated high...... changes in this evolution due to changes in the climate and associated sea levels. We analyzed the morphologic evolution of a series of barrier islands over the last decades using maps, aerial photographs and satellite images. This decadal morphologic evolution was coupled to the frequency and intensity...

  20. Identification of Key Barriers in Workforce Development

    Energy Technology Data Exchange (ETDEWEB)



    This report documents the identification of key barriers in the development of an adequate national security workforce as part of the National Security Preparedness Project, being performed under a Department of Energy/National Nuclear Security Administration grant. Many barriers exist that prevent the development of an adequate number of propertly trained national security personnel. Some barriers can be eliminated in a short-term manner, whereas others will involve a long-term strategy that takes into account public policy.

  1. Barrier Engineered Quantum Dot Infrared Photodetectors (United States)


    AFRL-RV-PS- AFRL-RV-PS- TR-2015-0111 TR-2015-0111 BARRIER ENGINEERED QUANTUM DOT INFRARED PHOTODETECTORS Sanjay Krishna Center for High Technology...2011 – 22 May 2012 4. TITLE AND SUBTITLE Barrier Engineered Quantum Dot Infrared Photodetectors 5a. CONTRACT NUMBER FA9453-12-1-0336 5b. Unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT To investigate barrier engineered designs to reduce the dark current in quantum dot infrared

  2. Perceived Barriers to Walking for Physical Activity


    Dunton, Genevieve F.; Schneider, Margaret


    Introduction Although the health benefits of walking for physical activity have received increasing research attention, barriers specific to walking are not well understood. In this study, questions to measure barriers to walking for physical activity were developed and tested among college students. The factor structure, test–retest and internal consistency reliability, and discriminant and criterion validity of the perceived barriers were evaluated. Methods A total of 305 undergraduate stud...

  3. Barriers for realisation of energy savings in buildings; Barrierer for realisering af energibesparelser i bygninger

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, O.M.


    Many years' efforts within the energy labelling area have shown large saving potentials in heating and use of electricity in buildings. At the same time it has been proved that these saving potentials, even when economically advantageous, only are cashed to a limited extent. The reason to this is ascribed to barriers that meet the individual building owner who wants to start saving energy. Most barriers are known and a lot of these have been sought overcome for some time. The questions are how many barriers still exist, have new barriers arisen and the character of these barriers. On this background the objective of this survey has been to concretize and study the barriers, which are blocking reasonable energy savings. Focus has especially been on barriers for realisation of heating savings, but through a general evaluation of energy savings of barriers other forms of energy saving methods have been taken into consideration. Special interest has been directed towards houses, typically one family houses, which are affected by the Energy Labelling Scheme. The concept barriers include all kinds of barriers, also barriers that not are acknowledged as barriers by the individual house owner, or that on closer inspection turn out to be something else than actual barriers. This note suggests an alternative inertia model, in order to create an idea of the inertness characteristic of the many house owners who understand the message but fail to act on it. (BA)

  4. Barriers to Health Care for Transgender Individuals (United States)

    Safer, Joshua D.; Coleman, Eli; Feldman, Jamie; Garofalo, Robert; Hembree, Wylie; Radix, Asa; Sevelius, Jae


    Purpose of Review Transgender persons suffer significant health disparities and may require medical intervention as part of their care. The purpose of this manuscript is to briefly review the literature characterizing barriers to health care for transgender individuals and to propose research priorities to understand mechanisms of those barriers and interventions to overcome them. Recent Findings Current research emphasizes sexual minorities’ self report of barriers, rather than using direct methods. The biggest barrier to health care reported by transgender individuals is lack of access due to lack of providers who are sufficiently knowledgeable on the topic. Other barriers include: financial barriers, discrimination, lack of cultural competence by providers, health systems barriers and socioeconomic barriers. Summary National research priorities should include rigorous determination of the capacity of the United States health care system to provide adequate care for transgender individuals. Studies should determine knowledge and biases of the medical work force across the spectrum of medical training with regard to transgender medical care; adequacy of sufficient providers for the care required, larger social structural barriers and status of a framework to pay for appropriate care. As well, studies should propose and validate potential solutions to address identified gaps. PMID:26910276

  5. Exercise barriers in Korean colorectal cancer patients. (United States)

    Kang, Dong-Woo; Chung, Jae Youn; Lee, Mi Kyung; Lee, Junga; Park, Ji-Hye; Kim, Dong-Il; Jones, Lee W; Ahn, Joong Bae; Kim, Nam Kyu; Jeon, Justin Y


    To identify barriers to exercise in Korean colorectal cancer patients and survivors, and to analyze differences in exercise barriers by age, gender, treatment status, and physical activity level. A total of 427 colorectal cancer patients and survivors from different stages and medical status completed a self-administered questionnaire that surveyed their barriers to exercise and exercise participation. The greatest perceived exercise barriers for the sampled population as a whole were fatigue, low level of physical fitness, and poor health. Those under 60-years old reported lack of time (p=0.008), whereas those over 60 reported low level of physical fitness (p=0.014) as greater exercise barriers than their counterparts. Women reported fatigue as a greater barrier than men (pACSM guidelines, cancer-related exercise barriers were additionally reported (p<0.001), compared to those who were. Our study suggests that fatigue, low level of physical fitness, and poor health are most reported exercise barriers for Korean colorectal cancer survivors and there are differences in exercise barriers by age, sex, treatment status, and physical activity level. Therefore, support for cancer patients should be provided considering these variables to increase exercise participation.

  6. Sports participation after rehabilitation: Barriers and facilitators

    National Research Council Canada - National Science Library

    Jaarsma, Eva A; Dekker, Rienk; Geertzen, Jan H.B; Dijkstra, Pieter


    Objective: To analyse barriers to, and facilitators of, sports participation among people with physical disabilities after rehabilitation and to compare differences between inactive and active participants...

  7. Radon barrier: Method of testing airtightness

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn; Buch-Hansen, Thomas Cornelius


    The test method NBI 167/02 Radon membrane: Test of airtightness can be used for determining the airtightness of a radon barrier as a system solution. The test determines the air infiltration through the radon barrier for a number of levels of air pressure differences. The airflow through versus...... of the barrier with the low air pressure, through a well-defined opening, as a modification of the test method in general. Results, obtained using the improved test method, are shown for a number of radon barriers tested....

  8. Barriers Approach to Innovation in Academic Libraries

    Directory of Open Access Journals (Sweden)

    Fu-Hsuan Chuang


    Full Text Available Innovation in academic libraries is not a brand new issue. Academic libraries can benefit from successful innovation, since innovation is a key contributor to gaining and sustaining competitive advantage for survival. Building on two case studies, 28 participants from leadership teams to practitioners are involved, the qualitative findings identified the specific two types of barriers that academic libraries face by applying a barriers approach to innovation, that’s, environmental and organizational barriers. Especially, seven dimensions of two types of barriers to innovation are found.

  9. Pratt & Whitney thermal barrier coatings

    Energy Technology Data Exchange (ETDEWEB)

    Bornstein, N. [United Technologies Research Center, East Hartford, CT (United States); Marcin, J. [Pratt & Whitney Aircraft Co., East Hartford, CT (United States)


    The objective of the Advanced Turbine Systems (ATS) Program is to develop ultra-high efficient, environmentally superior, and cost competitive gas turbine systems. The operating profiles of these industrial gas turbines are long, less cyclic with fewer transients-compared with those for aircraft gas turbine engines. Therefore, creep rather than thermal fatigue, becomes primary life-limiting for hot section components. Thermal barrier coatings (TBCs) will be used to achieve the objectives of the program. TBCs allow surface temperatures to increase without compromising the structural properties of the alloy. TBCs typically consist of a ceramic insulating layer, deposited onto the substrate with an intervening metallic layer, which imparts oxidation protection to the substrate and provides a surface to which the ceramic layer can adhere.

  10. Polyspermy barriers: a plant perspective. (United States)

    Tekleyohans, Dawit G; Mao, Yanbo; Kägi, Christina; Stierhof, York-Dieter; Groß-Hardt, Rita


    A common denominator of sexual reproduction in many eukaryotic species is the exposure of an egg to excess sperm to maximize the chances of reproductive success. To avoid potential harmful or deleterious consequences of supernumerary sperm fusion to a single female gamete (polyspermy), many eukaryotes, including plants, have evolved barriers preventing polyspermy. Typically, these checkpoints are implemented at different stages in the reproduction process. The virtual absence of unambiguous reports of naturally occurring egg cell polyspermy in flowering plants is likely reflecting the success of this multiphasic strategy and highlights the difficulty to trace this presumably rare event. We here focus on potential polyspermy avoidance mechanisms in plants and discuss them in light of analogous processes in animals. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  11. Reusable Thermal Barrier for Insulation Gaps (United States)

    Saladee, C. E.


    Filler composed of resilient, heat-resistant materials. Thermal barrier nestles snugly in gap between two tiles with minimal protrusion beyond faces of surrounding tiles. When removed from gap, barrier springs back to nearly original shape. Developed for filling spaces between tiles on Space Shuttle, also used in furnaces and kilns.

  12. Barriers to surgical care in Nepal

    NARCIS (Netherlands)

    Loenhout, J.A.F. van; Delbiso, T.D.; Gupta, S.; Amatya, K.; Kushner, A.L.; Cuesta, J. Gil; Guha-Sapir, D.


    BACKGROUND: Various barriers exist that preclude individuals from undergoing surgical care in low-income countries. Our study assessed the main barriers in Nepal, and identified individuals most at risk for not receiving required surgical care. METHODS: A countrywide survey, using the Surgeons

  13. Precast concrete barrier crash testing : final report. (United States)


    The objectives of this project were to crash test the Oregon Standard (32-inch) F-shape precast concrete barrier and the Oregon Tall (42-inch) F-shape precast concrete barrier against the new NCHRP Report 350 standards, to ensure compliance of these ...

  14. Rocket Motor Joint Construction Including Thermal Barrier (United States)

    Steinetz, Bruce M. (Inventor); Dunlap, Patrick H., Jr. (Inventor)


    A thermal barrier for extremely high temperature applications consists of a carbon fiber core and one or more layers of braided carbon fibers surrounding the core. The thermal barrier is preferably a large diameter ring, having a relatively small cross-section. The thermal barrier is particularly suited for use as part of a joint structure in solid rocket motor casings to protect low temperature elements such as the primary and secondary elastomeric O-ring seals therein from high temperature gases of the rocket motor. The thermal barrier exhibits adequate porosity to allow pressure to reach the radially outward disposed O-ring seals allowing them to seat and perform the primary sealing function. The thermal barrier is disposed in a cavity or groove in the casing joint, between the hot propulsion gases interior of the rocket motor and primary and secondary O-ring seals. The characteristics of the thermal barrier may be enhanced in different applications by the inclusion of certain compounds in the casing joint, by the inclusion of RTV sealant or similar materials at the site of the thermal barrier, and/or by the incorporation of a metal core or plurality of metal braids within the carbon braid in the thermal barrier structure.

  15. Overcoming Blocks and Barriers to Creativity. (United States)

    Raudsepp, Eugene


    Organizational barriers to creativity are examined. It is noted that resistance to change is a major impediment to creative problem solving in most organizations. Understanding the barriers to change that exist is viewed to help people exercise and develop their creativity more fully and effectively. (MP)

  16. Knowledge, Attitude and Barriers towards Children Immunization ...

    African Journals Online (AJOL)

    Knowledge, Attitude and Barriers towards Children Immunization among Women in Selected Rural Primary Health Centres. ... For barriers, about 53% reported they have no confidence in the quality and safety of vaccines being used while 62% reported that health workers are not sufficiently trained. For attitude, most ...

  17. Assessing Barriers to Women's Career Adjustment. (United States)

    McWhirter, Ellen Hawley; Torres, Danielle; Rasheed, Saba


    Women face external career barriers (sexual harassment, discrimination, lower socioeconomic status, racism, homophobia, physical limitations, lack of mentors) as well as individual/social barriers (self-efficacy expectations, low-outcome expectations, skill deficits, multiple role stress). Tools such as interviews, qualitative tests, and…

  18. Barrier bucket experiment at the AGS

    Directory of Open Access Journals (Sweden)

    M. Fujieda


    Full Text Available A barrier bucket experiment with two dedicated barrier cavities was performed at the Brookhaven AGS. One of the barrier cavities was a magnetic alloy (MA–loaded cavity and the other was a ferrite-loaded cavity. They generated a single sine wave with a peak voltage of 40 kV at a repetition rate of 351 kHz. A barrier rf system was established with these cavities and five bunches from the AGS booster were accumulated. A total of 3×10^{13} protons were stored without beam loss, and were successfully rebunched and accelerated. The longitudinal emittance growth was observed during accumulation by the barrier bucket, the blowup factor of which was about 3. The longitudinal mismatch between the rf bucket and the beam bunch was the main reason for the emittance growth. The potential distortions by beam loading of the ferrite cavity and the overshooting voltage of the MA cavity disturbed the smooth debunching.

  19. Barriers to physical activity among working mothers. (United States)

    Dombrowski, Jill J


    Working mothers experience several barriers to physical activity. If these barriers can be identified by occupational health nurses and they can partner with working mothers to reduce these perceived barriers, the health of these workers can be improved and chronic disease risk prevented. The purpose of this study was to measure the effect of self-regulatory efficacy on physical activity among working mothers and to describe specific barriers to physical activity. The Barriers Specific Self-Efficacy Scale (BARSE) and the Kaiser Physical Activity Survey (KPAS) were used to measure the variables. Self-regulatory efficacy was found to be a strong predictor of physical activity in a diverse sample of working mothers who did not meet current recommendations for physical activity. Occupational health nurses can use these findings to design programs for groups and for counseling individuals. Copyright 2011, SLACK Incorporated.

  20. Initial contact of glioblastoma cells with existing normal brain endothelial cells strengthen the barrier function via fibroblast growth factor 2 secretion: a new in vitro blood-brain barrier model. (United States)

    Toyoda, Keisuke; Tanaka, Kunihiko; Nakagawa, Shinsuke; Thuy, Dinh Ha Duy; Ujifuku, Kenta; Kamada, Kensaku; Hayashi, Kentaro; Matsuo, Takayuki; Nagata, Izumi; Niwa, Masami


    Glioblastoma multiforme (GBM) cells invade along the existing normal capillaries in brain. Normal capillary endothelial cells function as the blood-brain barrier (BBB) that limits permeability of chemicals into the brain. To investigate whether GBM cells modulate the BBB function of normal endothelial cells, we developed a new in vitro BBB model with primary cultures of rat brain endothelial cells (RBECs), pericytes, and astrocytes. Cells were plated on a membrane with 8 μm pores, either as a monolayer or as a BBB model with triple layer culture. The BBB model consisted of RBEC on the luminal side as a bottom, and pericytes and astrocytes on the abluminal side as a top of the chamber. Human GBM cell line, LN-18 cells, or lung cancer cell line, NCI-H1299 cells, placed on either the RBEC monolayer or the BBB model increased the transendothelial electrical resistance (TEER) values against the model, which peaked within 72 h after the tumor cell application. The TEER value gradually returned to baseline with LN-18 cells, whereas the value quickly dropped to the baseline in 24 h with NCI-H1299 cells. NCI-H1299 cells invaded into the RBEC layer through the membrane, but LN-18 cells did not. Fibroblast growth factor 2 (FGF-2) strengthens the endothelial cell BBB function by increased occludin and ZO-1 expression. In our model, LN-18 and NCI-H1299 cells secreted FGF-2, and a neutralization antibody to FGF-2 inhibited LN-18 cells enhanced BBB function. These results suggest that FGF-2 would be a novel therapeutic target for GBM in the perivascular invasive front.

  1. Applications of dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Falkenstein, Z.


    Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. As an introduction of this type of gas discharge, the main plasmaphysical features of sinusoidal-driven DBDs (transient, non-thermal plasmas at atmospheric pressure) will be described, and plasmachemical reaction pathways for the generation of ozone will be briefly discussed. The generation of atomic oxygen for ozone synthesis leads inevitably to the second application of DBDs, the non-thermal oxidation of volatile organic compounds (VOCs) in dry and humid air. Another application of DBDs is the generation of excited dimers and exiplexes for the production of incoherent (V)UV/visible light. The last and latest application of DBDs is the surface processing near atmospheric pressures. As an example, results of photoresist ashing on Si wafers in an oxygen plasma will be shown as function of gas pressure, gap spacing, and applied frequency. The surface of the etched photoresist is characterized by profilometry and scanning electron microscopy (SEM). The possibility of material deposition with DBDs will also be presented, where DBDs in acetylene lead to fast substrate deposition. Here, only the effects of the gas pressure and gap distance are explored.

  2. Optically enhanced blood-brain-barrier crossing of plasmonic-active nanoparticles in preclinical brain tumor animal models (United States)

    Yuan, Hsiangkuo; Wilson, Christy M.; Li, Shuqin; Fales, Andrew M.; Liu, Yang; Grant, Gerald; Vo-Dinh, Tuan


    Nanotechnology provides tremendous biomedical opportunities for cancer diagnosis, imaging, and therapy. In contrast to conventional chemotherapeutic agents where their actual target delivery cannot be easily imaged, integrating imaging and therapeutic properties into one platform facilitates the understanding of pharmacokinetic profiles, and enables monitoring of the therapeutic process in each individual. Such a concept dubbed "theranostics" potentiates translational research and improves precision medicine. One particular challenging application of theranostics involves imaging and controlled delivery of nanoplatforms across blood-brain-barrier (BBB) into brain tissues. Typically, the BBB hinders paracellular flux of drug molecules into brain parenchyma. BBB disrupting agents (e.g. mannitol, focused ultrasound), however, suffer from poor spatial confinement. It has been a challenge to design a nanoplatform not only acts as a contrast agent but also improves the BBB permeation. In this study, we demonstrated the feasibility of plasmonic gold nanoparticles as both high-resolution optical contrast agent and focalized tumor BBB permeation-inducing agent. We specifically examined the microscopic distribution of nanoparticles in tumor brain animal models. We observed that most nanoparticles accumulated at the tumor periphery or perivascular spaces. Nanoparticles were present in both endothelial cells and interstitial matrices. This study also demonstrated a novel photothermal-induced BBB permeation. Fine-tuning the irradiating energy induced gentle disruption of the vascular integrity, causing short-term extravasation of nanomaterials but without hemorrhage. We conclude that our gold nanoparticles are a powerful biocompatible contrast agent capable of inducing focal BBB permeation, and therefore envision a strong potential of plasmonic gold nanoparticle in future brain tumor imaging and therapy.

  3. A binding-site barrier affects imaging efficiency of high affinity amyloid-reactive peptide radiotracers in vivo.

    Directory of Open Access Journals (Sweden)

    Jonathan S Wall

    Full Text Available Amyloid is a complex pathology associated with a growing number of diseases including Alzheimer's disease, type 2 diabetes, rheumatoid arthritis, and myeloma. The distribution and extent of amyloid deposition in body organs establishes the prognosis and can define treatment options; therefore, determining the amyloid load by using non-invasive molecular imaging is clinically important. We have identified a heparin-binding peptide designated p5 that, when radioiodinated, was capable of selectively imaging systemic visceral AA amyloidosis in a murine model of the disease. The p5 peptide was posited to bind effectively to amyloid deposits, relative to similarly charged polybasic heparin-reactive peptides, because it adopted a polar α helix secondary structure. We have now synthesized a variant, p5R, in which the 8 lysine amino acids of p5 have been replaced with arginine residues predisposing the peptide toward the α helical conformation in an effort to enhance the reactivity of the peptide with the amyloid substrate. The p5R peptide had higher affinity for amyloid and visualized AA amyloid in mice by using SPECT/CT imaging; however, the microdistribution, as evidenced in micro-autoradiographs, was dramatically altered relative to the p5 peptide due to its increased affinity and a resultant "binding site barrier" effect. These data suggest that radioiodinated peptide p5R may be optimal for the in vivo detection of discreet, perivascular amyloid, as found in the brain and pancreatic vasculature, by using molecular imaging techniques; however, peptide p5, due to its increased penetration, may yield more quantitative imaging of expansive tissue amyloid deposits.

  4. Shakeoff Ionization near the Coulomb Barrier Energy (United States)

    Sharma, Prashant; Nandi, T.


    We measure the projectile K x-ray spectra as a function of the beam energies around the Coulomb barrier in different collision systems. The energy is scanned in small steps around the barrier aiming to explore the nuclear effects on the elastically scattered projectile ions. The variation of the projectile x-ray energy with the ion-beam energies exhibits an unusual increase in between the interaction barrier and fusion barrier energies. This additional contribution to the projectile ionization can be attributed to the shakeoff of outer-shell electrons of the projectile ions due to the sudden nuclear recoil (˜10-21 sec ) caused by the attractive nuclear potential, which gets switched on near the interaction barrier energy. In the sudden approximation limit, the theoretical shakeoff probability calculation due to the nuclear recoil explains the observed data well. In addition to its fundamental interest, such processes can play a significant role in dark matter detection through the possible mechanism of x-ray emissions, where the weakly interacting massive particle-nucleus elastic scattering can lead to the nuclear-recoil-induced inner-shell vacancy creations. Furthermore, the present work may provide new prospects for atomic physics research at barrier energies as well as provide a novel technique to perform barrier distribution studies for two-body systems.

  5. Numerical simulations of capillary barrier field tests

    Energy Technology Data Exchange (ETDEWEB)

    Morris, C.E. [Univ. of Wollongong (Australia); Stormont, J.C. [Univ. of New Mexico, Albuquerque, NM (United States)


    Numerical simulations of two capillary barrier systems tested in the field were conducted to determine if an unsaturated flow model could accurately represent the observed results. The field data was collected from two 7-m long, 1.2-m thick capillary barriers built on a 10% grade that were being tested to investigate their ability to laterally divert water downslope. One system had a homogeneous fine layer, while the fine soil of the second barrier was layered to increase its ability to laterally divert infiltrating moisture. The barriers were subjected first to constant infiltration while minimizing evaporative losses and then were exposed to ambient conditions. The continuous infiltration period of the field tests for the two barrier systems was modelled to determine the ability of an existing code to accurately represent capillary barrier behavior embodied in these two designs. Differences between the field test and the model data were found, but in general the simulations appeared to adequately reproduce the response of the test systems. Accounting for moisture retention hysteresis in the layered system will potentially lead to more accurate modelling results and is likely to be important when developing reasonable predictions of capillary barrier behavior.

  6. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.


    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  7. Applications of dielectric barrier discharges

    Energy Technology Data Exchange (ETDEWEB)

    Falkenstein, Z.


    Dielectric barrier discharges (DBDs) in oxygen and air are well established for the production of large quantities of ozone and are more recently being applied to a wider range of plasmachemical processes. Here, the application of DBDs for ozone synthesis, the non-thermal oxidation of volatile organic compounds (VOCs) in air, the generation of incoherent (V)UV radiation and surface processing (etching, ashing) is presented. The main plasmaphysical features of sinusoidally-driven DBDs (transient, filamented, non-thermal plasmas at atmospheric pressure) are described, and a simple plasmachemical reaction pathway for ozone synthesis are give. Experimental results on the degradation of VOCs (2-propanol, trichloroethylene, carbon tetrachloride), as well as byproduct formation is presented for stand-alone DBD treatment, as well as for simultaneous (V)UV illumination of the discharge. Illumination of the discharge with (V)UV can change the plasmachemistry by enhanced formation of certain species of radicals--and thereby change byproduct formation--but also can change the discharge physics, known as the Joshi effect. As an example for generation of excited dimers and exiplexes for the production of incoherent UV light, experimental results on a XeBr* excimer UV light source are presented. Effects of the total and partial pressure of a Xe/Br{sub 2} system, the gap spacing and the applied driving frequency on the UV radiant efficiency are shown. For the application of DBDs for surface processing, experimental results of photoresist ashing on Si wafers using DBDs in oxygen are shown function of gas pressure, gap spacing and applied frequency.

  8. Barrierer for realisering af energibesparelser i bygninger

    DEFF Research Database (Denmark)

    Jensen, Ole Michael


    For få bygningsejere går i gang med at investere i energibesparelser. Årsagen tilskrives en række barrierer, som møder den enkelte bygningsejer, når denne vil i gang med at foretage energirenoveringer. Men ikke alle barrierer handler om barrierer i traditionel forstand, men om tilbageholdenhed. Den...... tilbageholdenhed, som mange bygningsejere har over for energirenovering, gælder snarere en manglende anerkendelse fra omverdenen, en manglende tro på, at der kan spares noget og en manglende lyst til at se håndværkere i huset....

  9. Telerobotics in rehabilitation: Barriers to a virtual existence (United States)

    Leifer, Larry; Vanderloos, Machiel; Michalowski, Stefan


    The topics covered include the following: the need for telerobotics in rehabilitation; barriers to telerobotics technology in rehabilitation and health care; institutional barriers; technical barriers; and a partial view of the future.

  10. Brain pericytes from stress-susceptible pigs increase blood-brain barrier permeability in vitro

    Directory of Open Access Journals (Sweden)

    Vandenhaute Elodie


    Full Text Available Abstract Background The function of pericytes remains questionable but with improved cultured technique and the use of genetically modified animals, it has become increasingly clear that pericytes are an integral part of blood–brain barrier (BBB function, and the involvement of pericyte dysfunction in certain cerebrovascular diseases is now emerging. The porcine stress syndrome (PSS is the only confirmed, homologous model of malignant hyperthermia (MH in veterinary medicine. Affected animals can experience upon slaughter a range of symptoms, including skeletal muscle rigidity, metabolic acidosis, tachycardia and fever, similar to the human syndrome. Symptoms are due to an enhanced calcium release from intracellular stores. These conditions are associated with a point mutation in ryr1/hal gene, encoding the ryanodine receptor, a calcium channel. Important blood vessel wall muscle modifications have been described in PSS, but potential brain vessel changes have never been documented in this syndrome. Methods In the present work, histological and ultrastructural analyses of brain capillaries from wild type and ryr1 mutated pigs were conducted to investigate the potential impairment of pericytes, in this pathology. In addition, brain pericytes were isolated from the three porcine genotypes (wild-type NN pigs; Nn and nn pigs, bearing one or two (n mutant ryr1/hal alleles, respectively, and tested in vitro for their influence on the permeability of BBB endothelial monolayers. Results Enlarged perivascular spaces were observed in ryr1-mutant samples, corresponding to a partial or total detachment of the astrocytic endfeet. These spaces were electron lucent and sometimes filled with lipid deposits and swollen astrocytic feet. At the ultrastructural level, brain pericytes did not seem to be affected because they showed regular morphology and characteristics, so we aimed to check their ability to maintain BBB properties in vitro. Our results indicated

  11. Nanofiber mat spinal cord dressing-released glutamate impairs blood-spinal cord barrier

    Directory of Open Access Journals (Sweden)

    Dorota Sulejczak


    Full Text Available An excessive glutamate level can result in excitotoxic damage and death of central nervous system (CNS cells, and is involved in the pathogenesis of many CNS diseases. It may also be related to a failure of the blood-spinal cord barrier (BSCB. This study was aimed at examining the effects of extended administration of monosodium glutamate on the BSCB and spinal cord cells in adult male Wistar rats. The glutamate was delivered by subarachnoidal application of glutamate-carrying electrospun nanofiber mat dressing at the lumbar enlargement level. Half of the rats with the glutamate-loaded mat application were treated systemically with the histone deacetylase inhibitor valproic acid. A group of intact rats and a rat group with subarachnoidal application of an ‘empty’ (i.e., carrying no glutamate nanofiber mat dressing served as controls. All the rats were euthanized three weeks later and lumbar fragments of their spinal cords were harvested for histological, immunohistochemical and ultrastructural studies. The samples from controls revealed normal parenchyma and BSCB morphology, whereas those from rats with the glutamate-loaded nanofiber mat dressing showed many intraparenchymal microhemorrhages of variable sizes. The capillaries in the vicinity of the glutamate-carrying dressing (in the meninges and white matter alike were edematous and leaky, and their endothelial cells showed degenerative changes: extensive swelling, enhanced vacuo­lization and the presence of vascular intraluminal projections. However, endothelial tight junctions were generally well preserved. Some endothelial cells were dying by necrosis or apoptosis. The adjacent parenchyma showed astrogliosis with astrocytic hypertrophy and swelling of perivascular astrocytic feet. Neurons in the parenchyma revealed multiple symptoms of degeneration, including, inter alia, perikaryal, dendritic and axonal swelling, and destruction of organelles. All the damage symptoms were slightly less

  12. Market and Policy Barriers to Energy Storage Deployment

    Energy Technology Data Exchange (ETDEWEB)

    Bhatnagar, Dhruv [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Currier, Aileen [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez, Jacquelynne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ma, Ookie [Dept. of Energy (DOE), Washington DC (United States) Office of Energy Efficiency and Renewable Energy; Kirby, Brendan [Consultant


    Electric energy storage technologies can provide numerous grid services; there are a number of factors that restrict their current deployment. The most significant barrier to deployment is high capital costs, though several recent deployments indicate that capital costs are decreasing and energy storage may be the preferred economic alternative in certain situations. However, a number of other market and regulatory barriers persist, limiting further deployment. These barriers can be categorized into regulatory barriers, market (economic) barriers, utility and developer business model barriers, cross-cutting barriers and technology barriers.

  13. Markers for blood-brain barrier integrity

    DEFF Research Database (Denmark)

    Saunders, Norman R; Dziegielewska, Katarzyna M; Møllgård, Kjeld


    known when first introduced, but seem to have been forgotten since. Understanding these limitations is important because Evans blue is still the most commonly used marker of brain barrier integrity and those using it seem oblivious to problems arising from its in vivo application. The introduction......In recent years there has been a resurgence of interest in brain barriers and various roles their intrinsic mechanisms may play in neurological disorders. Such studies require suitable models and markers to demonstrate integrity and functional changes at the interfaces between blood, brain......, and cerebrospinal fluid. Studies of brain barrier mechanisms and measurements of plasma volume using dyes have a long-standing history, dating back to the late nineteenth-century. Their use in blood-brain barrier studies continues in spite of their known serious limitations in in vivo applications. These were well...

  14. Vapor-barrier Vacuum Isolation System (United States)

    Weinstein, Leonard M. (Inventor); Taminger, Karen M. (Inventor)


    A system includes a collimated beam source within a vacuum chamber, a condensable barrier gas, cooling material, a pump, and isolation chambers cooled by the cooling material to condense the barrier gas. Pressure levels of each isolation chamber are substantially greater than in the vacuum chamber. Coaxially-aligned orifices connect a working chamber, the isolation chambers, and the vacuum chamber. The pump evacuates uncondensed barrier gas. The barrier gas blocks entry of atmospheric vapor from the working chamber into the isolation chambers, and undergoes supersonic flow expansion upon entering each isolation chamber. A method includes connecting the isolation chambers to the vacuum chamber, directing vapor to a boundary with the working chamber, and supersonically expanding the vapor as it enters the isolation chambers via the orifices. The vapor condenses in each isolation chamber using the cooling material, and uncondensed vapor is pumped out of the isolation chambers via the pump.

  15. Breaking the Education/Service Barrier. (United States)

    Dexter, Phyllis A.; Laidig, Juanita


    Discusses the barriers blocking communication between nursing education and nursing service. Notes that the gap between the two is too infrequently bridged. Recommends changes in the nursing curriculum regarding nursing care plans, discharge planning, and patient planning. (JOW)

  16. Barriers to adherence in cystic fibrosis

    DEFF Research Database (Denmark)

    Bregnballe, Vibeke; Schiøtz, Peter Oluf


    Objectives: The objectives of the present study was to explore barriers to treatment adherence perceived by young CF patients and their parents and to identify what kind of support the young patients and their parents request from the CF center. Methods: A questionnaire survey of a cohort of young...... Danish patients with cystic fibrosis aged 14 to 25 years and their parents. Conclusions: The present study showed that the majority of adolescents with CF and their parents experienced barriers to treatment adherence. Patients and parents agreed that the three most common barriers encountered lack...... of time, forgetfulness and unwillingness to take medication in public. A significant, positive correlation was found between the number of barriers and the perceived treatment burden. Additionally, we found that almost half of the adolescents and half of the parents conveyed a desire for more information...

  17. Low-impact, high toughness transportation barriers. (United States)


    Alternatives to existing transportation truck escape ramps and crash barriers are examined using arrays of : wood, bamboo, and fiberglass structural elements that act as energy absorbers as they deform. The : behaviors of each material type are analy...

  18. Evapotranspiration studies for protective barriers: Experimental plans

    Energy Technology Data Exchange (ETDEWEB)

    Link, S.O.; Waugh, W.J.


    This document describes a general theory and experimental plans for predicting evapotranspiration in support of the Protective Barrier Program. Evapotranspiration is the combined loss of water from plants and soil surfaces to the atmosphere. 45 refs., 1 fig., 4 tabs.

  19. Communicating across barriers at home and abroad

    Energy Technology Data Exchange (ETDEWEB)

    McDonald, J.W.


    This paper intends to catalyze the exchange of experience among technical communicators in meeting the challenge of communicating across a multitude of barriers: linguistic, disciplinary, cultural, political, intellectual, and emotional.

  20. Barriers to Physical Activity on University Student (United States)

    Jajat; Sultoni, K.; Suherman, A.


    The purpose of the research is to analyze the factors that become barriers to physical activity in university students based on physical activity level. An internet-based survey was conducted. The participants were 158 University students from Universitas Pendidikan Indonesia. Barriers to Physical Activity Quiz (BPAQ) were used to assessed the factors that become barriers to physical activity in university students. IPAQ (short form) were used to assessed physical activity level. The results show there was no differences BPAQ based on IPAQ level. But when analyzed further based on seven factors barriers there are differences in factors “social influence and lack of willpower” based IPAQ level. Based on this it was concluded that the “influence from other and lack of willpower” an inhibiting factor on students to perform physical activity.

  1. Overcoming Barriers to Shared Decision Making (United States)

    ... to a palliative care specialist or social worker. Barrier: Disagreeing with the doctor Solution: In shared decision making, the patient and doctor are partners. And sometimes, partners disagree. Communication is critical if a disagreement occurs. If a ...

  2. Airport Barriers to Entry in the US

    National Research Council Canada - National Science Library

    Dresner M; Windle R; Yao Y


    An examination is conducted on the effects of three airport barriers to entry - slot controls, gate constraints, and gate utilisation during peak operating periods - on both yields and entry in the US airline...

  3. The BARRIERS scale -- the barriers to research utilization scale: A systematic review

    Directory of Open Access Journals (Sweden)

    Thompson David S


    Full Text Available Abstract Background A commonly recommended strategy for increasing research use in clinical practice is to identify barriers to change and then tailor interventions to overcome the identified barriers. In nursing, the BARRIERS scale has been used extensively to identify barriers to research utilization. Aim and objectives The aim of this systematic review was to examine the state of knowledge resulting from use of the BARRIERS scale and to make recommendations about future use of the scale. The following objectives were addressed: To examine how the scale has been modified, to examine its psychometric properties, to determine the main barriers (and whether they varied over time and geographic locations, and to identify associations between nurses' reported barriers and reported research use. Methods Medline (1991 to September 2009 and CINHAL (1991 to September 2009 were searched for published research, and ProQuest® digital dissertations were searched for unpublished dissertations using the BARRIERS scale. Inclusion criteria were: studies using the BARRIERS scale in its entirety and where the sample was nurses. Two authors independently assessed the study quality and extracted the data. Descriptive and inferential statistics were used. Results Sixty-three studies were included, with most using a cross-sectional design. Not one study used the scale for tailoring interventions to overcome identified barriers. The main barriers reported were related to the setting, and the presentation of research findings. Overall, identified barriers were consistent over time and across geographic locations, despite varying sample size, response rate, study setting, and assessment of study quality. Few studies reported associations between reported research use and perceptions of barriers to research utilization. Conclusions The BARRIERS scale is a nonspecific tool for identifying general barriers to research utilization. The scale is reliable as reflected in

  4. The BARRIERS scale -- the barriers to research utilization scale: A systematic review. (United States)

    Kajermo, Kerstin Nilsson; Boström, Anne-Marie; Thompson, David S; Hutchinson, Alison M; Estabrooks, Carole A; Wallin, Lars


    A commonly recommended strategy for increasing research use in clinical practice is to identify barriers to change and then tailor interventions to overcome the identified barriers. In nursing, the BARRIERS scale has been used extensively to identify barriers to research utilization. The aim of this systematic review was to examine the state of knowledge resulting from use of the BARRIERS scale and to make recommendations about future use of the scale. The following objectives were addressed: To examine how the scale has been modified, to examine its psychometric properties, to determine the main barriers (and whether they varied over time and geographic locations), and to identify associations between nurses' reported barriers and reported research use. Medline (1991 to September 2009) and CINHAL (1991 to September 2009) were searched for published research, and ProQuest(R) digital dissertations were searched for unpublished dissertations using the BARRIERS scale. Inclusion criteria were: studies using the BARRIERS scale in its entirety and where the sample was nurses. Two authors independently assessed the study quality and extracted the data. Descriptive and inferential statistics were used. Sixty-three studies were included, with most using a cross-sectional design. Not one study used the scale for tailoring interventions to overcome identified barriers. The main barriers reported were related to the setting, and the presentation of research findings. Overall, identified barriers were consistent over time and across geographic locations, despite varying sample size, response rate, study setting, and assessment of study quality. Few studies reported associations between reported research use and perceptions of barriers to research utilization. The BARRIERS scale is a nonspecific tool for identifying general barriers to research utilization. The scale is reliable as reflected in assessments of internal consistency. The validity of the scale, however, is doubtful


    Energy Technology Data Exchange (ETDEWEB)

    John Erjavec; Michael D. Mann; Ryan Z. Knutson; Michael L. Swanson; Michael E. Collings


    electrostatically enhanced barrier filter collection (EBFC). This concept combines electrostatic precipitation (ESP) with candle filters in a single unit. Similar technology has been recently proven on a commercial scale for atmospheric applications, but needed to be tested at high temperatures and pressures. The synergy obtained by combining the two control technologies into a single system should actually reduce filter system capital and operating costs and make the system more reliable. More specifically, the ESP is expected to significantly reduce candle filter load and also to limit ash reintrainment, allowing for full recovery of baseline pressure drop during backpulsing of the filters.

  6. Structural Stability of Tokamak Equilibrium: Transport Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Solano, E. R.


    A generalised theory of structural stability of differential equations is introduced and applied to the Grad-Shafranov equation. It is discussed how the formation and loss of transport barrier could be associated with the appearance/disappearance of equilibria. The equilibrium conjecture is presented: transport barriers are associated with locally diamagnetic regions in the plasma, and affected by the paramagnetism of the bootstrap current. (Author) 18 refs.

  7. Metal interfaces - Adhesive energies and electronic barriers (United States)

    Ferrante, J.; Smith, J. R.


    We report a fully self-consistent calculation of the electron number density, barrier height and adhesive energy as a function of separation in an aluminum-aluminum (100) contact. The local density approximation is used for exchange and correlation. The electron number density and barrier heights are strong functions of the separation. The range of strong chemical bonding is about 0.2 nm.

  8. Redundant protective barriers: minimizing operator occupational risk. (United States)

    Challa, Karthik; Warren, Stafford G; Danak, Subhash; Bates, Mark C


    The ubiquitous use of less invasive therapeutic angiographic procedures has created the milieu for long-term occupational risk of cancer and genetic defects. This study set out to determine the relative effectiveness of redundant radiation protective barriers and their impact on operator total-body-ionizing radiation exposure in the catheterization suite. Thermolucent dosimeter x-irradiation was measured inside and outside personal and movable protective barriers used concurrently during 50 consecutive procedures by a single operator. Additionally, the entrance/exit doses were recorded on the back and chest for all patients to provide insight into radiation scatter patterns. The x-ray beam had an average 90.8% decrement in energy traversing the patient's chest when entrance and exit doses were compared, suggesting a 3.3-fold greater operator scatter radiation exposure below the table compared with that above the table. All 0.5-mm lead equivalent personal barriers reduced operator exposure by 72-95%, whereas the 1.0-mm leaded personal barrier (overlapping gown) reduced exposure by 96%. The 0.75-mm leaded glasses reduced exposure to the left eye by 67%. A leaded left-hand glove reduced exposure by only 20%. The effective calculated operator radiation exposure risk reduction provided by the use of personal and movable barriers reduced the theoretical risk of fatal or nonfatal cancer by 22-fold while decreasing potential severe genetic effect by 25-fold in comparison to movable barriers alone. The optimal use of combined personal and movable (redundant) lead barriers results in a significant reduction in total-body operator radiation exposure in the catheterization laboratory. The use of redundant barriers in the catheterization suite is associated with a dramatic theoretical long-term occupational risk reduction and should be encouraged.

  9. Thermal barrier coating system having improved adhesion (United States)

    Bill, R. C.; Sovey, J. S. (Inventor)


    The adherence between a ceramic thermal barrier coating and a metal bond coating is improved by ion sputtering a ceramic film on the bond cost. A ceramic thermal barrier coating is then plasma-sprayed onto this primer film. This improves the integrity and strength of the interface between the plasma-sprayed ceramic layer and metallic bond coat which insures stronger adherence between the metal and the ceramic.

  10. Breaching barriers to collaboration in public spaces

    DEFF Research Database (Denmark)

    Heinemann, Trine; Mitchell, Robb


    Technology provoking disparate individuals to collaborate or share experiences in the public space faces a difficult barrier, namely the ordinary social order of urban places. We employed the notion of the breaching experiment to explore how this barrier might be overcome. We analyse responses to...... of life in public spaces. Arising from this, we argue for the importance of qualities such as availability, facilitation, perspicuous settings, and perspicuous participants to encourage and support co-located strangers to collaborate and share experiences....

  11. Frozen soil barriers for hazardous waste confinement

    Energy Technology Data Exchange (ETDEWEB)

    Dash, J.G.; Leger, R. [Univ. of Washington, Seattle, WA (United States); Fu, H.Y. [Univ. of California, Santa Barbara, CA (United States)


    Laboratory and full field measurements have demonstrated the effectiveness of artificial ground freezing for the containment of subsurface hazardous and radioactive wastes. Bench tests and a field demonstration have shown that cryogenic barriers are impenetrable to aqueous and non aqueous liquids. As a result of the successful tests the US Department of Energy has designated frozen ground barriers as one of its top ten remediation technologies.

  12. Model assessment of protective barriers: Part 3

    Energy Technology Data Exchange (ETDEWEB)

    Fayer, M.J.; Rockhold, M.L.; Holford, D.J.


    Radioactive waste exists at the US Department of Energy's (DOE's) Hanford Site in a variety of locations, including subsurface grout and tank farms, solid waste burial grounds, and contaminated soil sites. Some of these waste sites may need to be isolated from percolating water to minimize the potential for transport of the waste to the ground water, which eventually discharges to the Columbia River. Multilayer protective barriers have been proposed as a means of limiting the flow of water through the waste sites (DOE 1987). A multiyear research program (managed jointly by Pacific Northwest Laboratory (PNL) and Westinghouse Hanford Company for the DOE) is aimed at assessing the performance of these barriers. One aspect of this program involves the use of computer models to predict barrier performance. Three modeling studies have already been conducted and a test plan was produced. The simulation work reported here was conducted by PNL and extends the previous modeling work. The purpose of this report are to understand phenomena that have been observed in the field and to provide information that can be used to improve hydrologic modeling of the protective barrier. An improved modeling capability results in better estimates of barrier performance. Better estimates can be used to improve the design of barriers and the assessment of their long-term performance.

  13. Sports participation after rehabilitation: Barriers and facilitators. (United States)

    Jaarsma, Eva A; Dekker, Rienk; Geertzen, Jan H B; Dijkstra, Pieter U


    To analyse barriers to, and facilitators of, sports participation among people with physical disabilities after rehabilitation and to compare differences between inactive and active participants regarding these experienced barriers and facilitators. Participants were 1,223 adults (mean age 51.6 years, standard deviation 15.1 years) treated in the Rehabilitation Centre of the University Medical Center Groningen, who completed a questionnaire. The questionnaire consisted of a self-constructed questionnaire regarding barriers and facilitators. Fifty-eight percent of the participants were active in sports after their rehabilitation. Younger age and a higher level of education were positively associated with sports participation, whereas using assistive devices and experiencing environmental barriers were negatively associated. Facilitators of sports participation were health, fun and increasing physical strength, and advice from rehabilitation professionals. Rehabilitation professionals should emphasize the health benefits of, and enjoyment from, sports participation for people with physical disabilities. They should repeatedly remind people with physical disabilities to stay/become active after completing their rehabilitation programme. Rehabilitation professionals should also provide information about strategies to reduce environmental barriers to sports participation, which could help people using assistive devices to overcome these barriers.

  14. Addressing language barriers to healthcare in India. (United States)

    Narayan, Lalit


    In spite of a growing recognition of the importance of doctor-patient communication, the issue of language barriers to healthcare has received very little attention in India. The Indian population speaks over 22 major languages with English used as the lingua franca for biomedicine. Large-scale internal migration has meant that health workers are encountering increasing instances of language discordance within clinical settings. Research done predominantly in the West has shown language discordance to significantly affect access to care, cause problems of comprehension and adherence, and decrease the satisfaction and quality of care. Addressing language barriers to healthcare in India requires a stronger political commitment to providing non-discriminatory health services, especially to vulnerable groups such as illiterate migrant workers. Research will have to address three broad areas: the ways in which language barriers affect health and healthcare, the efficacy of interventions to overcome language barriers, and the costs of language barriers and efforts to overcome them. There is a need to address such barriers in health worker education and clinical practice. Proven strategies such as hiring multilingual healthcare workers, providing language training to health providers, employing in situ translators or using telephone interpretation services will have to be evaluated for their appropriateness to the Indian context. Internet-based initiatives, the proliferation of mobile phones and recent advances in machine translation promise to contribute to the solution. Copyright 2013, NMJI.

  15. Current-voltage relation for thin tunnel barriers: Parabolic barrier model

    DEFF Research Database (Denmark)

    Hansen, Kim; Brandbyge, Mads


    We derive a simple analytic result for the current-voltage curve for tunneling of electrons through a thin uniform insulating layer modeled by a parabolic barrier. Our model, which goes beyond the Wentzel–Kramers–Brillouin approximation, is applicable also in the limit of highly transparant...... barriers subject to high voltages, and thus provides a more realistic description for this situation compared to the widely used rectangular barrier model. ©2004 American Institute of Physics....

  16. New treatments for restoring impaired epidermal barrier permeability: skin barrier repair creams. (United States)

    Draelos, Zoe Diana


    Skin health depends on an intact barrier composed of protein-rich corneocytes surrounded by the lamellar intercellular lipids. This barrier provides waterproof protection for the body, preventing infection, regulating electrolyte balance, maintaining body temperature, and providing a mechanism for sensation. Damage to the skin barrier results in skin disease that can be treated by a variety of externally applied substances, such as ceramides, hyaluronic acid, licorice extracts, dimethicone, petrolatum, and paraffin wax. These substances are found in moisturizers that are sold as cosmetics and in prescriptions as 510(k) devices. This contribution examines the formulation and effect of skin barrier creams. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Overcoming barriers to Clean Development Mechanism projects

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, J. [OECD, Paris (France); Kamel, S. [UNEP Risoe Centre on Energy, Climate and Sustainable Development URC, Roskilde (Denmark)


    The market for Clean Development Mechanism (CDM) projects is continuing to grow rapidly, with the current portfolio expecting to deliver 2 billion tons of CO2-eq greenhouse gas (GHG) emission reductions by 2012, equivalent to 17% of Annex I Parties' base year GHG emissions. In total, governments and companies have earmarked over USD11 billion for CDM funding to 2012. This study analyses the various barriers to CDM market expansion in developing countries, and makes recommendations on how some of them can be removed or reduced. It also examines the distribution of CDM projects amongst regions and sectors. Different types of barriers can impede the development of CDM projects. These include: National-level barriers not related specifically to the CDM such as the policy or legislative framework within which a CDM project operates, e.g. electricity-related regulations that constrain generation by independent power producers; National-level CDM-related barriers such as institutional capability/effectiveness or lack of awareness about CDM potential. For example, delays in host country approval of CDM projects can dampen interest in CDM project development; Project-related issues including availability (or not) of underlying project finance, or other country or project-related risks that render the performance of the project uncertain; International-level barriers such as constraints on project eligibility (e.g. on land use and forestry projects), available guidance and decisions (e.g. with respect to the inclusion of carbon capture and storage projects), etc. Thus, barriers to CDM development can arise at different parts of the CDM project cycle. The relative importance of particular barriers varies between countries as well as over time. A combination of factors is needed to drive growth in a country's CDM activity. This includes the presence of attractive CDM opportunities, a positive investment climate, and an enabling policy and legislative framework (in

  18. Reduced barrier efficiency in axillary stratum corneum. (United States)

    Watkinson, A; Lee, R S; Moore, A E; Pudney, P D A; Paterson, S E; Rawlings, A V


    The skin of the axilla is cosmetically important with millions of consumers daily applying antiperspirant/deodorant products. Despite this, we know virtually nothing about axillary skin or how antiperspirant (AP) use impacts upon it. To characterize the axillary stratum corneum and determine whether this is a unique skin type, we have looked at stratum corneum composition and function, particularly its barrier properties, and compared it with other body sites. Transepidermal water loss (TEWL) and corneosurfametry (CSM) revealed a reduced barrier function in the axilla. HPTLC analysis of the stratum corneum lipids demonstrated statistically elevated levels of fatty acids, ceramides, and particularly cholesterol in the axilla. Both ceramide and cholesterol did not appear to change with depth, indicating that they were predominantly of stratum corneum origin. On the other hand, at least some of the fatty acid had a sebaceous origin. We hypothesized that the reduced barrier function might be owing to the changes in the crucial ceramide : cholesterol ratio. To address this, we used a combination of attenuated total reflectance-Fourier-transformed infrared spectroscopy (ATR-FTIR) with cyanoacrylate sampling. These results demonstrated more ordered lipid-lamellae phase behaviour in the axilla, suggesting that the elevated cholesterol might form crystal microdomains within the lipid lamellae, allowing an increase in water flux. Since an exaggerated application of antiperspirant had no effect upon the axilla barrier properties, it is concluded that this region of skin physiologically has a reduced barrier function.

  19. Vertical barriers with increased sorption capacities

    Energy Technology Data Exchange (ETDEWEB)

    Bradl, H.B. [Bilfinger + Berger Bauaktiengesellschaft, Mannheim (Germany)


    Vertical barriers are commonly used for the containment of contaminated areas. Due to the very small permeability of the barrier material which is usually in the order of magnitude of 10-10 m/s or less the advective contaminant transport can be more or less neglected. Nevertheless, there will always be a diffusive contaminant transport through the barrier which is caused by the concentration gradient. Investigations have been made to increase the sorption capacity of the barrier material by adding substances such as organoclays, zeolites, inorganic oxides and fly ashes. The contaminants taken into account where heavy metals (Pb) and for organic contaminants Toluole and Phenantrene. The paper presents results of model calculations and experiments. As a result, barrier materials can be designed {open_quotes}tailor-made{close_quotes} depending on the individual contaminant range of each site (e.g. landfills, gasworks etc.). The parameters relevant for construction such as rheological properties, compressive strength and permeability are not affected by the addition of the sorbents.

  20. Schottky barrier MOSFET systems and fabrication thereof (United States)

    Welch, J.D.


    (MOS) device systems-utilizing Schottky barrier source and drain to channel region junctions are disclosed. Experimentally derived results which demonstrate operation of fabricated N-channel and P-channel Schottky barrier (MOSFET) devices, and of fabricated single devices with operational characteristics similar to (CMOS) and to a non-latching (SRC) are reported. Use of essentially non-rectifying Schottky barriers in (MOS) structures involving highly doped and the like and intrinsic semiconductor to allow non-rectifying interconnection of, and electrical accessing of device regions is also disclosed. Insulator effected low leakage current device geometries and fabrication procedures therefore are taught. Selective electrical interconnection of drain to drain, source to drain, or source to source, of N-channel and/or P-channel Schottky barrier (MOSFET) devices formed on P-type, N-type and Intrinsic semiconductor allows realization of Schottky Barrier (CMOS), (MOSFET) with (MOSFET) load, balanced differential (MOSFET) device systems and inverting and non-inverting single devices with operating characteristics similar to (CMOS), which devices can be utilized in modulation, as well as in voltage controlled switching and effecting a direction of rectification. 89 figs.

  1. Understanding employment barriers among older Korean immigrants. (United States)

    Rhee, Min-Kyoung; Chi, Iris; Yi, Jaehee


    This study involved an in-depth exploration of the employment barriers of older Korean immigrants in Los Angeles. This qualitative study used data obtained from 6 focus groups and 5 individual interviews. Participants were 36 older Korean immigrants living in Los Angeles, aged 50 years and older, and either unemployed or employed in part-time or full-time work. A grounded theory analytical approach and constant comparison method were used. Ten major themes emerged as employment barriers for older Korean immigrants and were categorized as stereotype, human capital, and acculturation barriers. Ageism among employers specific to Korean culture, lack of English proficiency, separation from U.S. culture, marginalization from both Korean and U.S. cultures, and lack of social networks were important themes. In addition, older Korean immigrants experienced multiple interconnected barriers. The findings highlight the importance of using a multidimensional approach to explore employment barriers among older Korean immigrants who face multiple obstacles in finding jobs. Implications for local governments and Korean communities and potential services to support employment opportunities for older Korean immigrants are discussed. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail:

  2. Safety barriers for motorways : shoulder and bridge safety barriers and impact attenuators surveyed and assessed.

    NARCIS (Netherlands)

    Schoon, C.C. Heijer, T. Pol, W.H.M. van de & Jordaan, D.J.R.


    The various types and practical qualities of deformable and non-deformable safety barriers are listed. The main conclusions drawn from tests based on several safety criteria are : various types of deformable barriers (steel guide rails) perform well when hit by cars; various types of deformable

  3. Scope of Practice Barriers for Advanced Practice Registered Nurses: A State Task Force to Minimize Barriers. (United States)

    Lofgren, Maria A; Berends, Susan K; Reyes, Jimmy; Wycoff, Carmen; Kinnetz, Meghan; Frohling, Ami; Baker, Laura; Whitty, Sue; Dirks, Mary; OʼBrien, Mary


    Collegial relationships, administrative champions, and persistence are key components to breaking down barriers to advanced practice RN (APRN) practice. This article addresses how Iowa APRNs in a state-sanctioned task force identified barriers for practicing at the top of their licensure in a full practice authority state including defending the right to control the scope of nursing practice in court.

  4. Effectiveness of cable barriers, guardrails, and concrete barrier walls in reducing the risk of injury. (United States)

    Zou, Yaotian; Tarko, Andrew P; Chen, Erdong; Romero, Mario A


    Roadway departure crashes tend to be severe, especially when the roadside exposes the occupants of errant vehicles to excessive injury hazards. As a cost-effective method when the clear zone width is insufficient, road barriers are often installed to prevent errant vehicles from colliding with dangerous obstacles or traversing steep slopes. This paper focuses on the safety performance of road barriers in Indiana in reducing the risk of injury. The objective of the study presented here is to compare the risk of injury among different hazardous events faced by an occupant in a single-vehicle crash. The studied hazardous events include rolling over, striking three types of barriers (guardrails, concrete barrier walls, and cable barriers) with different barrier offsets to the edge of the travelled way, and striking various roadside objects. A total of 2124 single-vehicle crashes (3257 occupants) that occurred between 2008 and 2012 on 517 pair-matched homogeneous barrier and non-barrier segments were analyzed. A binary logistic regression model with mixed effects was estimated for vehicle occupants. The segment pairing process and the use of random effects were able to handle the commonality within the same segment pair as well as the heterogeneity across segment pairs. The modeling results revealed that hitting a barrier is associated with lower risk of injury than a high-hazard event (hitting a pole, rollover, etc.). The odds of injury are reduced by 39% for median concrete barrier walls offset 15-18ft from the travelled way, reduced by 65% for a guardrail face offset 5-55ft, reduced by 85% for near-side median cable barriers (offset between 10ft and 29ft), and reduced by 78% with far-side median cable barriers (offset at least 30ft). Comparing different types of barriers is useful where some types of barriers can be used alternatively. This study found that the odds of injury are 43% lower when striking a guardrail instead of a median concrete barrier offset 15-18ft

  5. Phonon tunneling through a double barrier system

    Energy Technology Data Exchange (ETDEWEB)

    Villegas, Diosdado [Departamento de Física, Universidad Central “Marta Abreu” de Las Villas, CP 54830, Santa Clara, Villa Clara (Cuba); Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico); León-Pérez, Fernando de [Centro Universitario de la Defensa de Zaragoza, Ctra. de Huesca s/n, E-50090 Zaragoza (Spain); Pérez-Álvarez, R. [Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, CP 62209 Cuernavaca (Mexico); Arriaga, J., E-mail: [Instituto de Física, Universidad Autónoma de Puebla, 18 Sur y San Claudio, Edif. 110A, Ciudad Universitaria, 72570 Puebla (Mexico)


    The tunneling of optical and acoustic phonons at normal incidence on a double-barrier is studied in this paper. Transmission coefficients and resonance conditions are derived theoretically under the assumption that the long-wavelength approximation is valid. It is shown that the behavior of the transmission coefficients for the symmetric double barrier has a Lorentzian form close to resonant frequencies and that Breit–Wigner's formula have a general validity in one-dimensional phonon tunneling. Authors also study the so-called generalized Hartman effect in the tunneling of long-wavelength phonons and show that this effect is a numerical artifact resulting from taking the opaque limit before exploring the variation with a finite barrier width. This study could be useful for the design of acoustic devices.

  6. Barriers to Medicaid participation among Florida dentists. (United States)

    Logan, Henrietta L; Catalanotto, Frank; Guo, Yi; Marks, John; Dharamsi, Shafik


    Finding dentists who treat Medicaid-enrolled children is a struggle for many parents. The purpose of this study was to identify non-reimbursement factors that influence the decision by dentists about whether or not to participate in the Medicaid program in Florida. Data from a mailed survey was analyzed using a logistic regression model to test the association of Medicaid participation with the Perceived Barriers and Social Responsibility variables. General and pediatric dentists (n=882) who identified themselves as either Medicaid (14%) or Non-Medicaid (86%) participants responded. Five items emerged as significant predictors of Medicaid participation, with a final concordance index of 0.905. Two previously unreported barriers to participation in Medicaid emerged: 1) dentists' perception of social stigma from other dentists for participating in Medicaid, and 2) the lack of specialists to whom Medicaid patients can be referred. This study provides new information about non-reimbursement barriers to Medicaid participation.

  7. Epidermal Growth Factor and Intestinal Barrier Function

    Directory of Open Access Journals (Sweden)

    Xiaopeng Tang


    Full Text Available Epidermal growth factor (EGF is a 53-amino acid peptide that plays an important role in regulating cell growth, survival, migration, apoptosis, proliferation, and differentiation. In addition, EGF has been established to be an effective intestinal regulator helping to protect intestinal barrier integrity, which was essential for the absorption of nutrients and health in humans and animals. Several researches have demonstrated that EGF via binding to the EGF receptor and subsequent activation of Ras/MAPK, PI3K/AKT, PLC-γ/PKC, and STATS signal pathways regulates intestinal barrier function. In this review, the relationship between epidermal growth factor and intestinal development and intestinal barrier is described, to provide a better understanding of the effects of EGF on intestine development and health.

  8. Constructing bottom barriers with met grouting

    Energy Technology Data Exchange (ETDEWEB)

    Shibazaki, M.; Yoshida, H. [Chemical Grouting Company, Tokyo (Japan)


    Installing a bottom barrier using conventional high pressure jetting technology and ensuring barrier continuity is challenging. This paper describes technology that has been developed and demonstrated for the emplacement of bottom barriers using pressures and flow rates above the conventional high pressure jetting parameters. The innovation capable of creating an improved body exceeding 5 meters in diameter has resulted in the satisfying connection and adherence between the treated columns. Besides, the interfaces among the improved bodies obtain the same strength and permeability lower than 1 x 10{sup -7} cm/sec as body itself. A wide variety of the thickness and the diameter of the improved mass optimizes the application, and the method is nearing completion. The paper explains an aspect and briefs case histories.

  9. Barriers To Successful Implementation of STEM Education

    Directory of Open Access Journals (Sweden)

    James A. Ejiwale


    Full Text Available The implementation of STEM education in schools across the globe is to prepare the future workforce with strong scientific and mathematical backgrounds to enhance skills development across STEM disciplines. However, for STEM education to achieve its goals and objectives, addressing the barriers to STEM education should start by fixing the problems at the elementary, junior and senior high school levels; the grassroots and potential feeders to colleges and universities. Since many nations including the United States of America is in dire need of the workforce with adequate preparation in science and mathematics to help address the nation’s economy that is in shambles, the barriers to its successful implementation should be identified and addressed. In this paper, (a the definition of STEM education and (b some barriers to successful implementation of STEM education are discussed and elaborated.

  10. The biological significance of brain barrier mechanisms

    DEFF Research Database (Denmark)

    Saunders, Norman R; Habgood, Mark D; Møllgård, Kjeld


    Barrier mechanisms in the brain are important for its normal functioning and development. Stability of the brain's internal environment, particularly with respect to its ionic composition, is a prerequisite for the fundamental basis of its function, namely transmission of nerve impulses....... In addition, the appropriate and controlled supply of a wide range of nutrients such as glucose, amino acids, monocarboxylates, and vitamins is also essential for normal development and function. These are all cellular functions across the interfaces that separate the brain from the rest of the internal...... environment of the body. An essential morphological component of all but one of the barriers is the presence of specialized intercellular tight junctions between the cells comprising the interface: endothelial cells in the blood-brain barrier itself, cells of the arachnoid membrane, choroid plexus epithelial...

  11. Compositional Safety Analysis using Barrier Certificates

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Pappas, George J.; Wisniewski, Rafael


    This paper proposes a compositional method for verifying the safety of a dynamical system, given as an interconnection of subsystems. The safety verification is conducted by the use of the barrier certificate method; hence, the contribution of this paper is to show how to obtain compositional...... conditions for safety verification. We show how to formulate the verification problem, as a composition of coupled subproblems, each given for one subsystem. Furthermore, we show how to find the compositional barrier certificates via linear and sum of squares programming problems. The proposed method makes...... it possible to verify the safety of higher dimensional systems, than the method for centrally computed barrier certificates. This is demonstrated by verifying the safety of an emergency shutdown of a wind turbine....

  12. Surface barrier research at the Hanford Site

    Energy Technology Data Exchange (ETDEWEB)

    Gee, G.W.; Ward, A.L.; Fayer, M.J. [Pacific Northwest National Lab., Richland, WA (United States)


    At the DOE Hanford Site, a field-scale prototype surface barrier was constructed in 1994 over an existing waste site as a part of a CERCLA treatability test. The above-grade barrier consists of a fine-soil layer overlying coarse layers of sands, gravels, basalt rock (riprap), and a low permeability asphalt layer. Two sideslope configurations, clean-fill gravel on a 10:1 slope and basalt riprap on a 2:1 slope, were built and are being tested. Design considerations included: constructability; drainage and water balance monitoring, wind and water erosion control and monitoring; surface revegetation and biotic intrusion; subsidence and sideslope stability, and durability of the asphalt layer. The barrier is currently in the final year of a three-year test designed to answer specific questions related to stability and long-term performance. One half of the barrier is irrigated such that the total water applied, including precipitation, is 480 mm/yr (three times the long-term annual average). Each year for the past two years, an extreme precipitation event (71 mm in 8 hr) representing a 1,000-yr return storm was applied in late March, when soil water storage was at a maximum. While the protective sideslopes have drained significant amounts of water, the soil cover (2-m of silt-loam soil overlying coarse sand and rock) has never drained. During the past year there was no measurable surface runoff or wind erosion. This is attributed to extensive revegetation of the surface. In addition, the barrier elevation has shown a small increase of 2 to 3 cm that is attributed to a combination of root proliferation and freeze/thaw activity. Testing will continue through September 1997. Performance data from the prototype barrier will be used by DOE in site-closure decisions at Hanford.

  13. Barriers to evidence-based medicine: a systematic review. (United States)

    Sadeghi-Bazargani, Homayoun; Tabrizi, Jafar Sadegh; Azami-Aghdash, Saber


    Evidence-based medicine (EBM) has emerged as an effective strategy to improve health care quality. The aim of this study was to systematically review and carry out an analysis on the barriers to EBM. Different database searching methods and also manual search were employed in this study using the search words ('evidence-based' or 'evidence-based medicine' or 'evidence-based practice' or 'evidence-based guidelines' or 'research utilization') and (barrier* or challenge or hinder) in the following databases: PubMed, Scopus, Web of Knowledge, Cochrane library, Pro Quest, Magiran, SID. Out of 2592 articles, 106 articles were finally identified for study. Research barriers, lack of resources, lack of time, inadequate skills, and inadequate access, lack of knowledge and financial barriers were found to be the most common barriers to EBM. Examples of these barriers were found in primary care, hospital/specialist care, rehabilitation care, medical education, management and decision making. The most common barriers to research utilization were research barriers, cooperation barriers and changing barriers. Lack of resources was the most common barrier to implementation of guidelines. The result of this study shows that there are many barriers to the implementation and use of EBM. Identifying barriers is just the first step to removing barriers to the use of EBM. Extra resources will be needed if these barriers are to be tackled. © 2014 John Wiley & Sons, Ltd.


    Directory of Open Access Journals (Sweden)

    Corina Pop Sitar


    Full Text Available The concept of e-procurement has many different meanings ranging from shopping on theinternet (through reverse auction to collaborative initiatives taking place in virtualmeetings. There are many forms of e-procurement that can be found in the literature. In thispaper we define the most important forms of e-procurement. Next, we present the mainbarriers of implementing an e-procurement found in the literature. Furthermore, we presenta matrix with the main barriers of e-procurement classified in four main categories. Finally,we elaborated for managers some guidelines in order to overcome the barriers ofimplementing e-procurement.

  15. LGBT Populations' Barriers to Cancer Care. (United States)

    Boehmer, Ulrike


    To describe lesbian, gay, bisexual, and transgender (LGBT) individuals' barriers to accessing and receiving quality cancer care. Published data on cancer care and studies of LGBT individuals. There is a clustering of barriers among LGBT individuals, which suggests multiple inequities exist in LGBT individuals' cancer care, although data on disparities along the cancer control continuum are not consistently available. Nurses can make a difference in LGBT individuals' cancer care by obtaining training on LGBT health and their cancer-related needs and by providing a welcoming and respectful relationship with LGBT patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Electrochemical cell structure including an ionomeric barrier (United States)

    Lambert, Timothy N.; Hibbs, Michael


    An apparatus includes an electrochemical half-cell comprising: an electrolyte, an anode; and an ionomeric barrier positioned between the electrolyte and the anode. The anode may comprise a multi-electron vanadium phosphorous alloy, such as VP.sub.x, wherein x is 1-5. The electrochemical half-cell is configured to oxidize the vanadium and phosphorous alloy to release electrons. A method of mitigating corrosion in an electrochemical cell includes disposing an ionomeric barrier in a path of electrolyte or ion flow to an anode and mitigating anion accumulation on the surface of the anode.

  17. Planning as a barrier for growth

    DEFF Research Database (Denmark)

    Olesen, Kristian; Carter, Helen


    In this paper we investigate how the discourse ‘planning as a barrier for growth’ has been structured in the public debate in Denmark, and how this discourse has created a political pressure to reform the Planning Act. We identify three main storylines, which support the discourse that planning...... constitutes a barrier for growth in the most rural areas of Denmark, framed as ‘Outer Denmark’ in the public debate. We argue that the contemporary critique of planning in Denmark has a distinct spatial dimension, in which planning deregulation is rationalisedseen as a means to boost development...

  18. Transmission line including support means with barriers (United States)

    Cookson, Alan H.


    A gas insulated transmission line includes an elongated outer sheath, a plurality of inner conductors disposed within and extending along the outer sheath, and an insulating gas which electrically insulates the inner conductors from the outer sheath. A support insulator insulatably supports the inner conductors within the outer sheath, with the support insulator comprising a main body portion including a plurality of legs extending to the outer sheath, and barrier portions which extend between the legs. The barrier portions have openings therein adjacent the main body portion through which the inner conductors extend.

  19. Permanent isolation surface barrier: Functional performance

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.


    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release.

  20. Adiabatic heavy-ion fusion potentials for fusion at deep sub-barrier ...

    Indian Academy of Sciences (India)

    barrier energies has been examined. The adiabatic limit of fusion barriers has been determined from experimental data using the barrier penetration model. These adiabatic barriers are consistent with the adiabatic fusion barriers derived from ...

  1. Perceived Sodium Reduction Barriers Among Patients with Chronic Kidney Disease: Which Barriers Are Important and Which Patients Experience Barriers?

    NARCIS (Netherlands)

    Meuleman, Yvette; Hoekstra, Tiny; Dekker, Friedo W.; van der Boog, Paul J. M.; van Dijk, Sandra; Navis, Gerjan; Vogt, Liffert; Bos, Willem Jan W.; van Montfrans, Gert A.; Boeschoten, Elisabeth W.; Verduijn, Marion; ten Brinke, Lucia; Heuveling, Lara; Storm, Marjolein; Prantl, Karen; Spijker, Anke; Kwakernaak, Arjan J.; Humalda, Jelmer K.; van Hirtum, Tonnie; Bokelaar, Robin; Loos, Marie-Louise; Bakker-Edink, Anke; Poot, Charlotte; Ciere, Yvette; Zwaard, Sophie; Veldscholte, Glenn


    The purposes of this study were to assess the importance of perceived sodium reduction barriers among patients with chronic kidney disease (CKD) and identify associated sociodemographic, clinical, and psychosocial factors. A total of 156 patients with CKD completed a questionnaire assessing sodium

  2. Advanced Thermal Barrier and Environmental Barrier Coating Development at NASA GRC (United States)

    Zhu, Dongming; Robinson, Craig


    This presentation summarizes NASA's advanced thermal barrier and environmental barrier coating systems, and the coating performance improvements that has recently been achieved and documented in laboratory simulated rig test conditions. One of the emphases has been placed on the toughness and impact resistance enhancements of the low conductivity, defect cluster thermal barrier coating systems. The advances in the next generation environmental barrier coatings for SiCSiC ceramic matrix composites have also been highlighted, particularly in the design of a new series of oxide-silicate composition systems to be integrated with next generation SiC-SiC turbine engine components for 2700F coating applications. Major technical barriers in developing the thermal and environmental barrier coating systems are also described. The performance and model validations in the rig simulated turbine combustion, heat flux, steam and calcium-magnesium-aluminosilicate (CMAS) environments have helped the current progress in improved temperature capability, environmental stability, and long-term fatigue-environment system durability of the advanced thermal and environmental barrier coating systems.

  3. Perforation rate of intraoral barriers for direct digital radiography. (United States)

    Choi, J-W


    This study aimed to assess the perforation rate of intraoral barriers for a direct digital sensor according to the barrier application. Four types of plastic barriers with different thicknesses and one type of latex finger cot were applied using six modified techniques. The perforations in barrier samples of six groups were examined by a water pressure test. The differences in the perforation rates among the six barrier applications were calculated. The least perforation occurred in Group 4 (0.08-mm-thick single barrier, 22%) and the most in Group 1 (0.04-mm-thick single barrier, 58%). An ANOVA test revealed statistical differences in the perforation rate among the groups (p = 0.00; 95% confidence interval, 0.326-0.403). The use of double barriers can be helpful in reducing the perforation rate of intraoral barriers.

  4. Deployment Efficiency and Barrier Effectiveness Testing of a Temporary Anti-Personnel (TAP) Barrier System.

    Energy Technology Data Exchange (ETDEWEB)

    Allen, David James [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hedrick, Charles D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martinez, Ruben [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)


    This report documents tests conducted by Sandia National Laboratories (SNL) on behalf of the U.S. Department of State to evaluate a temporary anti-personnel (TAP) barrier system developed by Mitigation Technologies. For this, the SNL Denial and Structural Assessment department developed a test protocol for the evaluation of the TAP barrier system on the basis of deployment efficiency and barrier effectiveness against a riotous/mob attack threat. The test protocol was then executed by SNL personnel and the results of the testing are documented.

  5. Ecological bridges and barriers in pelagic ecosystems (United States)

    Briscoe, Dana K.; Hobday, Alistair J.; Carlisle, Aaron; Scales, Kylie; Eveson, J. Paige; Arrizabalaga, Haritz; Druon, Jean Noel; Fromentin, Jean-Marc


    Many highly mobile species are known to use persistent pathways or corridors to move between habitat patches in which conditions are favorable for particular activities, such as breeding or foraging. In the marine realm, environmental variability can lead to the development of temporary periods of anomalous oceanographic conditions that can connect individuals to areas of habitat outside a population's usual range, or alternatively, restrict individuals from areas usually within their range, thus acting as ecological bridges or ecological barriers. These temporary features can result in novel or irregular trophic interactions and changes in population spatial dynamics, and, therefore, may have significant implications for management of marine ecosystems. Here, we provide evidence of ecological bridges and barriers in different ocean regions, drawing upon five case studies in which particular oceanographic conditions have facilitated or restricted the movements of individuals from highly migratory species. We discuss the potential population-level significance of ecological bridges and barriers, with respect to the life history characteristics of different species, and inter- and intra-population variability in habitat use. Finally, we summarize the persistence of bridge dynamics with time, our ability to monitor bridges and barriers in a changing climate, and implications for forecasting future climate-mediated ecosystem change.

  6. Open innovation practices and implementation barriers

    DEFF Research Database (Denmark)

    Burcharth, Ana Luiza Lara de Araújo; Søndergaard, Helle Alsted; Knudsen, Mette Præst

    A key organizational barrier related to the implementation of open innovation strategies refers to the unwillingness of employees to undertake extra-organizational knowledge transactions. Negative attitudes against the utilization of external knowledge (i.e. the Not-invented-here (NIH) syndrome...

  7. Cleansing Formulations That Respect Skin Barrier Integrity

    Directory of Open Access Journals (Sweden)

    Russel M. Walters


    Full Text Available Surfactants in skin cleansers interact with the skin in several manners. In addition to the desired benefit of providing skin hygiene, surfactants also extract skin components during cleansing and remain in the stratum corneum (SC after rinsing. These side effects disrupt SC structure and degrade its barrier properties. Recent applications of vibrational spectroscopy and two-photon microscopy in skin research have provided molecular-level information to facilitate our understanding of the interaction between skin and surfactant. In the arena of commercial skin cleansers, technologies have been developed to produce cleansers that both cleanse and respect skin barrier. The main approach is to minimize surfactant interaction with skin through altering its solution properties. Recently, hydrophobically modified polymers (HMPs have been introduced to create skin compatible cleansing systems. At the presence of HMP, surfactants assemble into larger, more stable structures. These structures are less likely to penetrate the skin, thereby resulting in less aggressive cleansers and the integrity of the skin barrier is maintained. In this paper, we reviewed our recent findings on surfactant and SC interactions at molecular level and provided an overview of the HM technology for developing cleansers that respect skin barrier.

  8. Understanding Motivators and Barriers to Physical Activity (United States)

    Patay, Mary E.; Patton, Kevin; Parker, Melissa; Fahey, Kathleen; Sinclair, Christina


    The purpose of this study was to understand the factors that influence physical activity among year-round residents in an isolated summer resort community. Specifically, we explored the personal, environmental, social, and culture-specific perceived motivators and barriers to physical activity. Participants were formally interviewed about their…

  9. Transcending communication barriers: A case for hybrid ...

    African Journals Online (AJOL)

    Therefore, communication can be improved by combining both feminine and masculine styles of communication, because male and female leaders can adapt to the demands of leadership in the transformational mode. Key words: secondary school; transformational leadership; channels of communication; cultural barriers ...

  10. Moisture barrier properties of xylan composite films (United States)

    Amit Saxena; Thomas J. Elder; Arthur J. Ragauskas


    Moisture barrier properties of films based on xylan reinforced with several cellulosic resources including nanocrystalline cellulose, acacia bleached kraft pulp fibers and softwood kraft fibers have been evaluated. Measurements of water vapor transmission rate (WVTR) were performed by a modification of the wet cup method described by ASTM E 96-95, indicating that...

  11. Motivations and Barriers in Promoting Preschool Education (United States)

    Küçükturan, A. Güler; Akbaba Altun, Sadegül


    This study is designed to explore the reasons for sending and not sending preschool age children to preschools at an early age by exploring the motivations for and barriers towards promoting preschool education in Turkey. It aimed to determine various stakeholders' perceptions, attitudes, and knowledge related to preschool education in order to…

  12. On the Existence of Compositional Barrier Certificates

    DEFF Research Database (Denmark)

    Sloth, Christoffer; Wisniewski, Rafael; Pappas, George J.


    analysis is to allow the verification of systems with a high dimension, by the verification of multiple lower dimensional subproblems. In the compositional safety analysis, a particular structure is imposed on the barrier certificate, restricting the applicability of the method. We show an example...

  13. Welfare Mothers: Barriers to Labor Force Entry. (United States)

    Shea, John R.

    Barriers to the labor force participation of women, particularly in low-income families, are examined in this paper. Reactions of nonworking mothers with dependent children to a hypothetical job offer are analyzed from data obtained in 1967 as part of the National Longitudinal Surveys of Labor Market Behavior. Multiple regression analysis shows…

  14. Single-Barrier-Varactor 200-GHz Tripler (United States)

    Choudhury, Debabani; Frerking, Margaret A.; Batelaan, Paul D.


    Single-barrier varactor in crossed waveguide serves as experimental frequency-tripling device with output at frequencies ranging from 186 to 207 GHz. Varactor has symmetrical capacitance-vs.-voltage characteristic and antisymmetrical dc current-vs.-voltage characteristic. As result, generates only odd-harmonic currents when radio-frequency voltage applied at zero dc bias.

  15. Flame retardant cotton barrier nonwovens for mattresses (United States)

    According to regulation CPSC 16 CFR 1633, every new residential mattress sold in the United States since July 2007 must resist ignition by open flame. An environmentally benign “green”, inexpensive way to meet this regulation is to use a low-cost flame retardant (FR) barrier fabric. In this study, a...

  16. Green FR Cotton Barrier Nonwovens: Progress Report (United States)

    This green barrier fabric is unique in sense that it is from a renewable resource, biodegradable, economical, employing greige (unbleached) cotton, thus, increasing its marketability. The recent open-flame standard (effective since July, 2007) for residential mattresses 16 CFR 1633 from CPSC has l...

  17. Breaking the Barriers to the Circular Economy

    NARCIS (Netherlands)

    Kirchherr, J.W.; Hekkert, M.P.; Bour, Ruben; Huijbrechtse-Truijens, Anne; Kostense-Smit, Erica; Muller, Jennifer


    The Copernicus Institute of Sustainable Development, Utrecht University, the Netherlands and Deloitte have jointly carried out research on barriers to the Circular Economy (CE) in the European Union. For this research, a survey with 153 businesses, 55 government officials and expert interviews with

  18. Barrier methods of birth control - slideshow (United States)

    ... gov/ency/presentations/100107.htm Barrier methods of birth control - series—Female normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Birth Control A.D.A.M., Inc. is accredited by ...

  19. Penetrating the Barriers to Teaching Higher Thinking. (United States)

    Supon, Viola


    Considers five ways to overcome barriers teachers face when they attempt to create thinking classrooms: (1) acquisition of conscious commitment; (2) legitimization of students' experiences; (3) integration of visualizing into the curriculum; (4) use of reflective analysis; and (5) diversification of perspectives. (SR)

  20. Barriers and facilitators to antiretroviral medication adherence ...

    African Journals Online (AJOL)

    Medication adherence is a complex behaviour with multiple determinants. Understanding the barriers and facilitators of adherence is invaluable for programme improvement, which assists the foundation of adherence intervention strategies. A qualitative study was conducted in six selected hospitals of Addis Ababa in 2008, ...

  1. Overcoming Barriers in the Media Center (United States)

    Winter, Clint


    Web 2.0 has revolutionized one's ability to teach students in new and exciting ways. Students with disabilities can now overcome many barriers that once kept them from being successful in the regular education classroom. Media specialists can effectively advocate for students with disabilities. School library media specialists have the ability to…

  2. Innovation drivers and barriers in food processing

    NARCIS (Netherlands)

    Fortuin, F.T.J.M.; Omta, S.W.F.


    Purpose - The food processing industry, confronted with increased global competition and more stringent customer demands, is pressurized to improve the pace and quality of its innovation processes. This paper aims to find out what factors constitute the main drivers and barriers to innovation and to

  3. Web Widgets Barriers for Visually Impaired Users. (United States)

    Seixas Pereira, Letícia; Archambault, Dominique


    Currently, websites are mainly composed of web widgets, dynamic elements and updatable sections - like autosuggest list, carousel, slideshow etc. In order to contribute with the development of accessible rich internet applications, this work aims to better understand the interaction of severely visually impaired users with these pages, gathering their main barriers and difficulties.

  4. Identifying Barriers to Study Abroad Program Participation (United States)

    McKinley, Karen E.


    University administrators, industry professionals, and government leaders encourage college students to participate in study abroad programs. Despite an increase in the number of students going abroad, the percentage of students participating in global programs remain low. This study identified barriers to study abroad program participation at a…

  5. Barriers To New Modes Of Horizontal Governance

    NARCIS (Netherlands)

    Termeer, C.J.A.M.


    Across the world public managers are attracted to the narratives of governance and networks. However, implementing new strategies of policy making is difficult, above all when these conflict with the rules and beliefs of existing institutions. This article explores the barriers public managers

  6. Message maps for Safety Barrier Awareness

    DEFF Research Database (Denmark)

    . The Danish DanWORM project has transferred this knowledge into two sets of 17 so-called “INFO-cards” or message maps, to be used by the employer and the employee, respectively. Such an INFO-card is developed for a specific group of risks and contains: • What needs to be observed, what safety barriers...

  7. Message maps for safety barrier awareness

    DEFF Research Database (Denmark)

    Jørgensen, Kirsten; Duijm, Nijs Jan; Troen, Hanne


    into two sets of 17 “INFO-cards” or message maps, to be used by the employer and the employee, respectively. Such an INFO-card is developed for a specific group of risks and contains: • What needs to be observed, what safety barriers are in place; • What needs to be assessed, the performance parameters...

  8. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Jungerstedt, J; Hellgren, Lars; Drachmann, Tue


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups ...

  9. Reconnaissance level study Mississippi storm surge barrier

    NARCIS (Netherlands)

    Van Ledden, M.; Lansen, A.J.; De Ridder, H.A.J.; Edge, B.


    This paper reports a reconnaissance level study of a storm surge barrier in the Mississippi River. Historical hurricanes have shown storm surge of several meters along the Mississippi River levees up to and upstream of New Orleans. Future changes due to sea level rise and subsidence will further

  10. Enablers & Barriers for Realizing Modularity Benefits

    DEFF Research Database (Denmark)

    Storbjerg, Simon Haahr; Brunø, Thomas Ditlev; Thyssen, Jesper


    are the organizational and systems related aspects. Recognizing the need for guidance to realize the benefits of modularity, the purpose of this study is through a literature study and a case study to improve the insight into the organizational and systems related enablers and barriers with regard to obtaining the full...

  11. Beaches, Dunes, and Barrier Islands. Habitat Pac. (United States)

    Fish and Wildlife Service (Dept. of Interior), Washington, DC.

    The materials in this educational packet are designed for use with students in grades 4 through 7. They consist of a leader overview, teaching guides and student data sheets for three activities, and a poster. The leader overview describes the nature of beaches, dunes, and barrier islands, tracing their development, settlement, and management and…

  12. Lifetime Modeling of Thermal Barrier Coatings

    NARCIS (Netherlands)

    Hille, T.S.


    Thermal barrier coatings (TBCs) are applied in gas turbines to enhance their thermal efficiency by isolating the metallic components from the aggressive hot gas. TBC lifetime is limited by damage processes originating at internal interfaces, which may ultimately lead to delamination and spallation.

  13. Remote Ischemia Preconditioning Attenuates Blood-Spinal Cord Barrier Breakdown in Rats Undergoing Spinal Cord Ischemia Reperfusion Injury: Associated with Activation and Upregulation of CB1 and CB2 Receptors. (United States)

    Jing, Na; Fang, Bo; Wang, Zhi-Lin; Ma, Hong


    Remote ischemic preconditioning (RIPC) has protective effects on spinal cord ischemia reperfusion (I/R) injury, but the potential mechanisms remain unclear. In our study, the effects and underlying mechanisms of RIPC on blood-spinal cord barrier (BSCB) breakdown following I/R injury were investigated. animals underwent intraperitoneal administration with cannabinoid-1 (CB1) receptor antagonist AM251, cannabinoid-2 (CB2) receptor antagonist AM630 or vehicle 15 minutes before three 3-minute occlusion-reperfusion cycles on the right femoral artery or a sham operation. 30 minutes after the preconditioning, aortic arch was exposed with or without 14-minute occlusion. Neurological function was assessed with Tarlov scoring system. The disruption of BSCB was assessed by measuring Evans Blue (EB) extravasation. The expression of tight junction protein occludin was determined by western blot analyses. The expression and localization of CB1 and CB2 receptors were assessed by western blot and immunofluorescence. RIPC attenuated the motor dysfunction, BSCB disruption and downregulation of occludin after I/R injury, which were impaired by blocking CB1 and CB2 receptors. Moreover, RIPC upregulated the elevated perivascular expression of CB1 and CB2 receptors following I/R injury. These results indicated that RIPC, through activation and upregulation of CB1 and CB2 receptors, was involved in preserving the integrity of BSCB after spinal cord I/R injury. © 2017 The Author(s). Published by S. Karger AG, Basel.

  14. Remote Ischemia Preconditioning Attenuates Blood-Spinal Cord Barrier Breakdown in Rats Undergoing Spinal Cord Ischemia Reperfusion Injury: Associated with Activation and Upregulation of CB1 and CB2 Receptors

    Directory of Open Access Journals (Sweden)

    Na Jing


    Full Text Available Background/Aims: Remote ischemic preconditioning (RIPC has protective effects on spinal cord ischemia reperfusion (I/R injury, but the potential mechanisms remain unclear. In our study, the effects and underlying mechanisms of RIPC on blood-spinal cord barrier (BSCB breakdown following I/R injury were investigated. Methods: animals underwent intraperitoneal administration with cannabinoid-1 (CB1 receptor antagonist AM251, cannabinoid-2 (CB2 receptor antagonist AM630 or vehicle 15 minutes before three 3-minute occlusion-reperfusion cycles on the right femoral artery or a sham operation. 30 minutes after the preconditioning, aortic arch was exposed with or without 14-minute occlusion. Neurological function was assessed with Tarlov scoring system. The disruption of BSCB was assessed by measuring Evans Blue (EB extravasation. The expression of tight junction protein occludin was determined by western blot analyses. The expression and localization of CB1 and CB2 receptors were assessed by western blot and immunofluorescence. Results: RIPC attenuated the motor dysfunction, BSCB disruption and downregulation of occludin after I/R injury, which were impaired by blocking CB1 and CB2 receptors. Moreover, RIPC upregulated the elevated perivascular expression of CB1 and CB2 receptors following I/R injury. Conclusions: These results indicated that RIPC, through activation and upregulation of CB1 and CB2 receptors, was involved in preserving the integrity of BSCB after spinal cord I/R injury.

  15. Clamshell excavation of a permeable reactive barrier (United States)

    Molfetta, Antonio Di; Sethi, Rajandrea


    Nowadays, permeable reactive barriers (PRB) are one of the most widespread techniques for the remediation of contaminated aquifers. Over the past 10 years, the use of iron-based PRBs has evolved from innovative to accepted standard practice for the treatment of a variety of groundwater contaminants (ITRC in: Permeable reactive barriers: lessons learned/new directions. The Interstate Technology and Regulatory Council, Permeable Reactive Barriers Team 2005). Although, a variety of excavation methods have been developed, backhoe excavators are often used for the construction of PRBs. The aim of this study is to describe the emplacement of a full-scale PRB and the benefits deriving from the use of a crawler crane equipped with a hydraulic grab (also known as clamshell excavator) in the excavation phases. The studied PRB was designed to remediate a chlorinated hydrocarbons plume at an old industrial landfill site, in Avigliana, near the city of Torino, in Italy. The continuous reactive barrier was designed to be 120 m long, 13 m deep, and 0.6 m thick. The installation of the barrier was accomplished using a clamshell for the excavation of the trench and a guar-gum slurry to support the walls. The performance of this technique was outstanding and allowed the installation of the PRB in 7 days. The degree of precision of the excavation was very high because of the intrinsic characteristics of this excavation tool and of the use of a concrete curb to guide the hydraulic grab. Moreover, the adopted technique permitted a saving of bioslurry thus minimizing the amount of biocide required.

  16. Transport Barriers in Bootstrap Driven Tokamaks (United States)

    Staebler, Gary


    Maximizing the bootstrap current in a tokamak, so that it drives a high fraction of the total current, reduces the external power required to drive current by other means. Improved energy confinement, relative to empirical scaling laws, enables a reactor to more fully take advantage of the bootstrap driven tokamak. Experiments have demonstrated improved energy confinement due to the spontaneous formation of an internal transport barrier in high bootstrap fraction discharges. Gyrokinetic analysis, and quasilinear predictive modeling, demonstrates that the observed transport barrier is due to the suppression of turbulence primarily due to the large Shafranov shift. ExB velocity shear does not play a significant role in the transport barrier due to the high safety factor. It will be shown, that the Shafranov shift can produce a bifurcation to improved confinement in regions of positive magnetic shear or a continuous reduction in transport for weak or negative magnetic shear. Operation at high safety factor lowers the pressure gradient threshold for the Shafranov shift driven barrier formation. The ion energy transport is reduced to neoclassical and electron energy and particle transport is reduced, but still turbulent, within the barrier. Deeper into the plasma, very large levels of electron transport are observed. The observed electron temperature profile is shown to be close to the threshold for the electron temperature gradient (ETG) mode. A large ETG driven energy transport is qualitatively consistent with recent multi-scale gyrokinetic simulations showing that reducing the ion scale turbulence can lead to large increase in the electron scale transport. A new saturation model for the quasilinear TGLF transport code, that fits these multi-scale gyrokinetic simulations, can match the data if the impact of zonal flow mixing on the ETG modes is reduced at high safety factor. This work was supported by the U.S. Department of Energy under DE-FG02-95ER54309 and DE-FC02

  17. Impacts of noise barriers on near-road air quality (United States)

    Baldauf, R.; Thoma, E.; Khlystov, A.; Isakov, V.; Bowker, G.; Long, T.; Snow, R.

    Numerous health studies conducted worldwide suggest an increase in the occurrence of adverse health effects for populations living, working, or going to school near large roadways. A study was designed to assess traffic emission impacts on air quality near a heavily traveled highway. The portion of highway studied included a section of open field and a section with a noise barrier adjacent to the road. In addition, the section containing the noise barrier included a portion with vegetation in the vicinity of the barrier. Thus, this field study provided an opportunity to evaluate near-road air quality with no barriers, with a noise barrier only, and with a noise barrier and vegetation adjacent to the road. Pollutants measured under these scenarios included carbon monoxide (CO) and particulate matter (PM). Measurements showed the effects of a noise barrier on near-road air quality. The presence of this structure often led to pollutant concentration reductions behind the barrier during meteorological conditions with winds directionally from the road. CO and PM number concentrations generally decreased between 15 and 50% behind the barrier. However, conditions occurred when pollutant concentrations were greater behind the barrier than when no barrier was present. These results imply that the presence of a noise barrier can lead to higher pollutant concentrations on the road during certain wind conditions. In addition, the study results suggested that the presence of mature trees in addition to the barrier further lowered PM number concentrations.

  18. Traveling towards disease: transportation barriers to health care access. (United States)

    Syed, Samina T; Gerber, Ben S; Sharp, Lisa K


    Transportation barriers are often cited as barriers to healthcare access. Transportation barriers lead to rescheduled or missed appointments, delayed care, and missed or delayed medication use. These consequences may lead to poorer management of chronic illness and thus poorer health outcomes. However, the significance of these barriers is uncertain based on existing literature due to wide variability in both study populations and transportation barrier measures. The authors sought to synthesize the literature on the prevalence of transportation barriers to health care access. A systematic literature search of peer-reviewed studies on transportation barriers to healthcare access was performed. Inclusion criteria were as follows: (1) study addressed access barriers for ongoing primary care or chronic disease care; (2) study included assessment of transportation barriers; and (3) study was completed in the United States. In total, 61 studies were reviewed. Overall, the evidence supports that transportation barriers are an important barrier to healthcare access, particularly for those with lower incomes or the under/uninsured. Additional research needs to (1) clarify which aspects of transportation limit health care access (2) measure the impact of transportation barriers on clinically meaningful outcomes and (3) measure the impact of transportation barrier interventions and transportation policy changes.

  19. Weather in Mountainous Terrain (Overcoming Scientific Barriers to Weather Support) (United States)


    Weather in Mountainous Terrain (Overcoming Scientific Barriers to Weather Support) Fiesta Resort & Conference Center Tempe, AZ February 1...Meteorology Overcoming Scientific Barriers to Weather Support Fiesta Resort & Conference Center Tempe, AZ February 1 & 2, 2010 Hosted by University

  20. Energy analysis of vehicle-to-cable barrier impacts. (United States)


    An accident reconstruction technique was developed for estimating the energy absorbed during an impact with a cable barrier system as well as the initial impact velocity. The kinetic energy absorbed during a cable barrier system impact is comprised o...

  1. Overcoming Barriers to Wind Development in Appalachian Coal Country

    Energy Technology Data Exchange (ETDEWEB)

    Brent Bailey; Evan Hansen


    This research project synthesizes existing data and communication from experts to assess barriers to wind development in Pennsylvania, Maryland, West Virginia, Virginia, and Kentucky, and makes recommendations where feasible to reduce or eliminate those barriers.

  2. Performance of Traffic Noise Barriers with Varying Cross-Section

    Directory of Open Access Journals (Sweden)

    Sanja Grubeša


    Full Text Available The efficiency of noise barriers largely depends on their geometry. In this paper, the performance of noise barriers was simulated using the numerical Boundary Element Method (BEM. Traffic noise was particularly considered with its standardized noise spectrum adapted to human hearing. The cross-section of the barriers was varied with the goal of finding the optimum shape in comparison to classical rectangular barriers. The barrier performance was calculated at different receiver points for a fixed barrier height and source position. The magnitude of the insertion loss parameter was used to evaluate the performance change, both in one-third octave bands and as the broadband mean insertion loss value. The proposed barriers of varying cross-section were also compared with a typical T-shape barrier of the same height.

  3. Therapeutic benefits of enhancing permeability barrier for atopic eczema

    Directory of Open Access Journals (Sweden)

    George Man


    Full Text Available The regulatory role of epidermal permeability barrier function in cutaneous inflammation has been well appreciated. While barrier disruption induces cutaneous inflammation, improvement of permeability barrier function alleviates inflammation. Studies have demonstrated that improvement of epidermal permeability barrier function not only prevents the development of atopic eczema, but also delays the relapse of these diseases. Moreover, enhancing the epidermal permeability barrier also alleviates atopic eczema. Furthermore, co-applications of barrier enhancing products with glucocorticoids can increase the therapeutic efficacy and reduce the adverse effects of glucocorticoids in the treatment of atopic eczema. Therefore, utilization of permeability barrier enhancing products alone or in combination with glucocorticoids could be a valuable approach in the treatment of atopic eczema. In this review, we discuss the benefits of improving the epidermal permeability barrier in the management of atopic eczema.

  4. Estuarine Shoreline and Barrier-Island Sandline Change Assessment Dataset (United States)

    U.S. Geological Survey, Department of the Interior — The Barrier Island and Estuarine Wetland Physical Change Assessment Dataset was created to calibrate and test probability models of barrier island sandline and...

  5. Decreasing barriers for nurse practitioner social entrepreneurship. (United States)

    Sharp, Dayle B; Monsivais, Diane


    To describe difficulties associated with the business-related aspects of practice in role transition of rural nurse practitioners (NPs), and to give practice implications. This focused ethnographic study derived data from semi-structured interviews. Participants provided information about rural NP practice ownership and barriers. The sample consisted of 24 rural NPs living throughout the United States. The majority were 51-60 years of age (45%) and females (93%) who had been in rural practice for 1 to over 20 years. NP social entrepreneurs experience difficulties related to scope of practice, business skills, and role conflict. To decrease barriers for NP clinic ownership and management, NPs need to receive education related to financing a rural practice, legal/regulatory practices, strategic planning, leadership, and clinic management. ©2014 American Association of Nurse Practitioners.

  6. Nuclear reactor vessel fuel thermal insulating barrier (United States)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.


    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  7. Delamination-Indicating Thermal Barrier Coatings (United States)

    Eldridge, Jeffrey I.


    The risk of premature failure of thermal barrier coatings (TBCs), typically composed of yttria-stabilized zirconia (YSZ), compromises the reliability of TBCs used to provide thermal protection for turbine engine components. Unfortunately, TBC delamination proceeds well beneath the TBC surface and cannot be monitored by visible inspection. Nondestructive diagnostic tools that could reliably probe the subsurface damage state of TBCs would alleviate the risk of TBC premature failure by indicating when the TBC needs to be replaced before the level of TBC damage threatens engine performance or safety. To meet this need, a new coating design for thermal barrier coatings (TBCs) that are self-indicating for delamination has been successfully implemented by incorporating a europium-doped luminescent sublayer at the base of a TBC composed of YSZ. The luminescent sublayer has the same YSZ composition as the rest of the TBC except for the addition of low-level europium doping and therefore does not alter TBC performance.

  8. Intestinal barrier in inflammatory bowel disease. (United States)

    Antoni, Lena; Nuding, Sabine; Wehkamp, Jan; Stange, Eduard F


    A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms. In this review, we provide an overview about the major components of this protective system as for example an intact epithelium, the synthesis of various antimicrobial peptides (AMPs) and the formation of the mucus layer. We highlight the crucial importance of their correct functioning for the maintenance of a proper intestinal function and the prevention of dysbiosis and disease. Barrier disturbances including a defective production of AMPs, alterations in thickness or composition of the intestinal mucus layer, alterations of pattern-recognition receptors, defects in the process of autophagy as well as unresolved endoplasmic reticulum stress result in an inadequate host protection and are thought to play a crucial role in the pathogenesis of the inflammatory bowel diseases Crohn's disease and ulcerative colitis.

  9. Intestinal barrier integrity and inflammatory bowel disease

    DEFF Research Database (Denmark)

    Holmberg, Fredrik Eric Olof; Pedersen, Jannie; Jørgensen, Peter


    Disruption of normal barrier function is a fundamental factor in the pathogenesis of inflammatory bowel disease, which includes increased epithelial cell death, modified mucus configuration, altered expression and distribution of tight junction-proteins, along with a decreased expression......, novel treatment strategies to accomplish mucosal healing and to re-establish normal barrier integrity in inflammatory bowel disease are warranted, and luminal stem cell-based approaches might have an intriguing potential. Transplantation of in vitro expanded intestinal epithelial stem cells derived...... either directly from mucosal biopsies or from directed differentiation of human pluripotent stem cells may constitute complementary treatment options for patients with mucosal damage, as intestinal epithelial stem cells are multipotent and may give rise to all epithelial cell types of the intestine...


    Energy Technology Data Exchange (ETDEWEB)



    This booklet contains project descriptions of work performed by the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM), Office of Science and Technology and International's (OST&I) Natural Barriers Targeted Thrust during Fiscal Year (FY) 2004. The Natural Barriers Targeted Thrust is part of OST&I's Science and Technology Program which supports the OCRWM mission to manage and dispose of high-level radioactive waste and spent nuclear fuel in a manner that protects health, safety, and the environment; enhances national and energy security; and merits public confidence. In general, the projects described will continue beyond FY 2004 assuming that the technical work remains relevant to the proposed Yucca Mountain Repository and sufficient funding is made available to the Science and Technology Program.

  11. DNA nanovehicles and the biological barriers

    DEFF Research Database (Denmark)

    Okholm, Anders Hauge; Kjems, Jørgen


    DNA is emerging as a smart material to construct nanovehicles for targeted drug delivery. The programmability of Watson-Crick base paring enables construction of defined and dynamic DNA nanostructures of almost arbitrary shape and DNA can readily be functionalized with a variety of molecular...... modules. The applications of DNA nanostructures are still in its infancy, but one of the high expectations are to deliver solutions for targeted therapy. Nucleic acids, however, do not easily enter cells unassisted and biological barriers and harsh nucleolytic conditions in the human body must also...... be overcome. Here, we highlight recent strategies for DNA nanostructures in drug delivery, DNA nanovehicles, to facilitate targeting and crossing of the biological barriers. In light of this, we discuss future solutions and challenges for DNA nanovehicles to unravel their great potential to facilitate...


    Directory of Open Access Journals (Sweden)

    Paulo Matias


    Full Text Available The population awareness of the physical exercise’s benefits is widely diffused. These benefits are particularly important in the elderly because, with increasing age, there is a decline of the musculoskeletal system and the maximum oxygen consumption which reduces the functional fitness of the elderly and can often lead to a significant decline in the quality of life. Despite this awareness, a large part of the population remains sedentary. It is important to know what the barriers are, so they can be circumvented in order to increase the engagement of the elderly population in existing physical activity programs.Objectives: This study aims to identify some of the personal, behavioral and environmental barriers that prevent older adults to be physically active.

  13. Cancer rehabilitation: increasing awareness and removing barriers. (United States)

    Paul, Kelly; Buschbacher, Ralph


    It has been more than 30 years since Lehman et al. published research identifying rehabilitation problems encountered at different cancer sites, the need for rehabilitation services, and gaps in the delivery of rehabilitation care. The lack of identification of patient problems and the lack of appropriate referral by physicians unfamiliar with the concept of rehabilitation were identified as primary barriers to optimal delivery of rehabilitation care. These are frustratingly the same barriers to cancer rehabilitation we see today. Recommendations have been made for finding better methods for identifying and managing the broader effects of cancer and its treatment and for integrating a more holistic interdisciplinary approach during and after the treatment of patients with cancer. The purpose of this supplement was to increase awareness of the role of rehabilitation in cancer care among the public and among medical professionals, as well as to stimulate further interest and training in the field of cancer rehabilitation.

  14. Streptococcus pyogenes translocates across an epithelial barrier. (United States)

    Sumitomo, Tomoko


    Streptococcus pyogenes is a β-hemolytic organism responsible for a wide variety of human diseases that commonly occur as self-limiting purulent diseases of the pharynx and skin. Although the occurrence of invasive infections by S. pyogenes is rare, mortality rates remain high even with progressive medical therapy. As a prerequisite for causing the severe invasive disease, S. pyogenes must invade underlying sterile tissues by translocating across the epithelial barrier. In this study, streptolysin S and SpeB were identified as the novel factors that facilitate bacterial translocation via degradation of intercellular junctions. Furthermore, we found that S. pyogenes exploits host plasminogen for acceleration of bacterial invasion into deeper tissues via tricellular tight junctions. Here, I would like to show our study on bacterial translocation across the epithelial barrier through paracellular route.

  15. Sensing of Barrier Tissue Disruption with an Organic Electrochemical Transistor


    Tria, Scherrine A.; Ramuz, Marc; Jimison, Leslie H.; Hama, Adel; Owens, Roisin M.


    The gastrointestinal tract is an example of barrier tissue that provides a physical barrier against entry of pathogens and toxins, while allowing the passage of necessary ions and molecules. A breach in this barrier can be caused by a reduction in the extracellular calcium concentration. This reduction in calcium concentration causes a conformational change in proteins involved in the sealing of the barrier, leading to an increase of the paracellular flux. To mimic this effect the calcium che...

  16. Blood-brain barrier permeability imaging using perfusion computed tomography

    Directory of Open Access Journals (Sweden)

    Avsenik Jernej


    Full Text Available Background. The blood-brain barrier represents the selective diffusion barrier at the level of the cerebral microvascular endothelium. Other functions of blood-brain barrier include transport, signaling and osmoregulation. Endothelial cells interact with surrounding astrocytes, pericytes and neurons. These interactions are crucial to the development, structural integrity and function of the cerebral microvascular endothelium. Dysfunctional blood-brain barrier has been associated with pathologies such as acute stroke, tumors, inflammatory and neurodegenerative diseases.

  17. Peptide Transport through the Blood-Brain Barrier (United States)


    cause glomerular nephropathies , (c) the potential antigenicity of the vector, i.e., some cationized heterologous proteins are highly immunogenic, (d...I diabetes . N. Enctl. J. Med. 312:1078-1084. 12. Pardridge, W.M. (1988): Recent advances in blood-brain barrier transport. Ann. Rev. Pharmacol...barrier. In: Pathophysiology of the Blood-Brain Barrier: Long Term Consequences of Barrier Dysfunction for the Brain (B.B. Johansson, C. Owman, and H



    Corina Pop Sitar


    The concept of e-procurement has many different meanings ranging from shopping on theinternet (through reverse auction) to collaborative initiatives taking place in virtualmeetings. There are many forms of e-procurement that can be found in the literature. In thispaper we define the most important forms of e-procurement. Next, we present the mainbarriers of implementing an e-procurement found in the literature. Furthermore, we presenta matrix with the main barriers of e-procurement classified...

  19. Market Opportunities and Barriers for Smart Buildings

    DEFF Research Database (Denmark)

    Ma, Zheng; Badi, Adrian; Jørgensen, Bo Nørregaard


    Buildings consume up to 42% of the global electricity and the primary emitter of greenhouse gas on the planet. Building efficiency is the largest growing segment in the US, the estimated global revenue by the building efficiency sector is around 210 million dollars, and constantly increases since....... Meanwhile, the result shows that the barriers can be eased or solved by open collaboration, information and risk sharing, and self-investment, etc. this paper also categorizes nine influential factors with discussions....

  20. Light Barrier for Non-Foil Packaging (United States)


    spices . PRINTPACK Inc. Atlanta, Ga Item No. 0010 Final Scientific Report 12/16/2010 Page 51 of 90 Final Scientific Report: Annex 6 Light Barrier...28.23 The processed pouches were stored at 4°C. Pouches left after microbiological testing for various pathogens were shipped on ice to Natick on 10-14...which would provide about a 95% assurance the product was pathogen free...the described 8 samples would only give a 90% assurance level (ref http

  1. Reconsolidated Salt as a Geotechnical Barrier

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Francis D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gadbury, Casey [USDOE Carlsbad Field Office, NM (United States)


    Salt as a geologic medium has several attributes favorable to long-term isolation of waste placed in mined openings. Salt formations are largely impermeable and induced fractures heal as stress returns to equilibrium. Permanent isolation also depends upon the ability to construct geotechnical barriers that achieve nearly the same high-performance characteristics attributed to the native salt formation. Salt repository seal concepts often include elements of reconstituted granular salt. As a specific case in point, the Waste Isolation Pilot Plant recently received regulatory approval to change the disposal panel closure design from an engineered barrier constructed of a salt-based concrete to one that employs simple run-of-mine salt and temporary bulkheads for isolation from ventilation. The Waste Isolation Pilot Plant is a radioactive waste disposal repository for defense-related transuranic elements mined from the Permian evaporite salt beds in southeast New Mexico. Its approved shaft seal design incorporates barrier components comprising salt-based concrete, bentonite, and substantial depths of crushed salt compacted to enhance reconsolidation. This paper will focus on crushed salt behavior when applied as drift closures to isolate disposal rooms during operations. Scientific aspects of salt reconsolidation have been studied extensively. The technical basis for geotechnical barrier performance has been strengthened by recent experimental findings and analogue comparisons. The panel closure change was accompanied by recognition that granular salt will return to a physical state similar to the halite surrounding it. Use of run-of-mine salt ensures physical and chemical compatibility with the repository environment and simplifies ongoing disposal operations. Our current knowledge and expected outcome of research can be assimilated with lessons learned to put forward designs and operational concepts for the next generation of salt repositories. Mined salt

  2. Hurricane Impact on Gulf Coast Barriers. (United States)


    259 19.0 2.80 3.48 1 o9,r10, 71 Po~rtO’Connor 981 137 145 L68 168 IFredprie 9 1:1179 Pascaigoula 943 234 t1r, 31:.65 3.65 Dato from 1t1 Havew Dauphin Island, is going to be rather limited. Some seaward-d irected trough and tabular sets of cross- A 1 km wide segment of low barrier flats in

  3. Engineered Barrier System: Physical and Chemical Environment

    Energy Technology Data Exchange (ETDEWEB)

    P. Dixon


    The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

  4. Controlling barrier penetration via exothermic iron oxidation. (United States)

    Wood, Daniel G; Brown, Marc B; Jones, Stuart A


    Exothermic iron oxidation is an elegant means to generate heat, with the potential to modulate barrier penetration if reaction kinetics can be controlled. This aim of this study was to gain a fundamental understanding of how these temperature change kinetics influenced barrier diffusion rate. Lidocaine transport through a hydrophilic carboxymethyl cellulose (CMC) gel was compared using two rapid iron oxidation reactions initiated by water (ExoRap(50), T(max)-47.7 ± 0.6 °C, t(max)-3.3 ± 0.6 min, ExoRap(60), T(max)-60.4 ± 0.3 °C, t(max)-9.3 ± 0.6 min) and a slower reaction initiated by oxygen (ExoSl(45)T(max)-ca. 44 °C, t(max) ca. 240 min). Temperature change induced by the oxygen initiated reaction (ExoSl(45)) was almost double those initiated by water (over 4h), but lidocaine diffusion was approximately 4 times higher for the latter (ExoRap(50), 555.61 ± 22.04 μg/cm(2)/h; ExoRap(60), 663.1 ± 50.95 μg/cm(2)/h; compared to ExoSl(45), 159.36 ± 29.44 μg/cm(2)/h). The large influence of temperature change kinetics on lidocaine diffusion suggested that transport was heavily dependent on temperature induced structural changes of the barrier. CMC, like many polymers adsorbs more water when exposed to moderate increases in temperature and this appeared to be a critical determinant of lidocaine barrier diffusion rate. Copyright © 2010 Elsevier B.V. All rights reserved.

  5. Concepts for Functional Restoration of Barrier Islands (United States)


    shrimp require tidal circulation and gradient in salinity within estuaries as a part of their juvenile growth cycle, which is promoted by the presence of...dynamically stable in that the barrier island is designed to allow morphologic evolution through time via migration and overwash, as long as the storm...island dimen- sions (width and elevation) required to maintain morphologic form and increase the potential for island recovery after a storm. For

  6. Engineered barriers for radioactive waste confinement


    Fernández, R


    Nuclear power plants generate long-lived radioactive waste of high toxicity. The security assessment of repositories destined to definitive confinement of radioactive waste has been studied for several decades. Deep geological repositories are technically feasible and begin to be built by some pioneer countries. The scientific evaluation of interactions between the different engineered barriers is studied by laboratory experiments, natural analogues and modeling studies. The three methods are...

  7. Healthcare barriers of refugees post-resettlement. (United States)

    Morris, Meghan D; Popper, Steve T; Rodwell, Timothy C; Brodine, Stephanie K; Brouwer, Kimberly C


    The majority of refugees spend the greater part of their lives in refugee camps before repatriation or resettlement to a host country. Limited resources and stress during residence in refugee camps can lead to a variety of acute and chronic diseases which often persist upon resettlement. However, for most resettled refugees little is known about their health needs beyond a health assessment completed upon entry. We conducted a qualitative pilot-study in San Diego County, the third largest area in California, USA for resettling refugees, to explore health care access issues of refugees after governmental assistance has ended. A total of 40 guided in-depth interviews were conducted with a targeted sample of informants (health care practitioners, employees of refugee serving organizations, and recent refugee arrivals) familiar with the health needs of refugees. Interviews revealed that the majority of refugees do not regularly access health services. Beyond individual issues, emerging themes indicated that language and communication affect all stages of health care access--from making an appointment to filling out a prescription. Acculturation presented increased stress, isolation, and new responsibilities. Additionally, cultural beliefs about health care directly affected refugees' expectation of care. These barriers contribute to delayed care and may directly influence refugee short- and long-term health. Our findings suggest the need for additional research into contextual factors surrounding health care access barriers, and the best avenues to reduce such barriers and facilitate access to existing services.

  8. Update on the glomerular filtration barrier (United States)

    Jarad, George; Miner, Jeffrey H.


    Purpose of the review The nephrology community lacks a unified view of protein sieving through the glomerular capillary wall (GCW). The GCW consists of three distinct but closely interacting layers: the fenestrated endothelium, with its glycocalyx; the podocytes, with their interdigitated foot processes and slit diaphragms; and the intervening glomerular basement membrane (GBM). Proteinuria is associated with abnormalities in any one layer, suggesting that each contributes to the glomerular filtration barrier (GFB). Proteinuria can also be induced in the context of a normal GCW. Here we review some classic studies as well as some newer concepts and present competing hypotheses about the GFB. Recent findings Two almost forgotten concepts have recently emerged. One group has challenged the exquisite selectivity of the GFB to albumin and suggested that proteinuria is the result of abnormal tubular uptake. There has also been a reemphasis on diffusion through the GBM as the driving force behind macromolecular filtration. New evidence suggests that the endothelial glycocalyx is an important charge-selective barrier. Summary We suggest viewing the GFB as a dynamic rather than as a rigid barrier, requiring three healthy layers and a hemodynamic steady state. Multiple challenges to studying the endothelium, the tubular handling of albumin, and the role of hemodynamic forces will require new tools, new hypotheses, and open minds. PMID:19374010

  9. Probing Microbial Interactions with the Mucus Barrier (United States)

    Ribbeck, Katharina

    Mucus is a biological gel that lines all wet epithelia in the body, including the mouth, lungs, and digestive tract, and has evolved to protect us from pathogenic invasion. Microbial pathogenesis in these mucosal systems, however, is often studied in mucus- free environments, which lack the geometric constraints and microbial interactions that are found in natural, three-dimensional mucus gels. To bridge this gap, my laboratory has developed a model test systems based on purified mucin polymers, the major gel-forming constituents of the mucus barrier. We use this model to understand how the mucus barrier influences bacterial virulence, and moreover, to elucidate strategies used by microbes to overcome the normal protective mucus barrier. I will discuss data showing that the mucus environment has a significant impact on the physiological behavior of microbes, including surface attachment, quorum sensing, the expression of virulence genes, and biofilm formation. The picture is emerging that mucins are key host players in the regulation of microbial virulence and are critical to consider when studying mucosal pathogenesis. Our work may also be the basis for the design of synthetic gels that mimic the basic selective properties and virulence-neutralizing capacity of mucus gels.

  10. Barriers and enablers to academic health leadership. (United States)

    Bharwani, Aleem; Kline, Theresa; Patterson, Margaret; Craighead, Peter


    Purpose This study sought to identify the barriers and enablers to leadership enactment in academic health-care settings. Design/methodology/approach Semi-structured interviews ( n = 77) with programme stakeholders (medical school trainees, university leaders, clinical leaders, medical scientists and directors external to the medical school) were conducted, and the responses content-analysed. Findings Both contextual and individual factors were identified as playing a role in affecting academic health leadership enactment that has an impact on programme development, success and maintenance. Contextual factors included sufficient resources allocated to the programme, opportunities for learners to practise leadership skills, a competent team around the leader once that person is in place, clear expectations for the leader and a culture that fosters open communication. Contextual barriers included highly bureaucratic structures, fear-of-failure and non-trusting cultures and inappropriate performance systems. Programmes were advised to select participants based on self-awareness, strong communication skills and an innovative thinking style. Filling specific knowledge and skill gaps, particularly for those not trained in medical school, was viewed as essential. Ineffective decision-making styles and tendencies to get involved in day-to-day activities were barriers to the development of academic health leaders. Originality/value Programmes designed to develop academic health-care leaders will be most effective if they develop leadership at all levels; ensure that the organisation's culture, structure and processes reinforce positive leadership practices; and recognise the critical role of teams in supporting its leaders.

  11. Use of Postpartum Care: Predictors and Barriers

    Directory of Open Access Journals (Sweden)

    Jessica N. DiBari


    Full Text Available This study aimed to identify actual and perceived barriers to postpartum care among a probability sample of women who gave birth in Los Angeles County, California in 2007. Survey data from the 2007 Los Angeles Mommy and Baby (LAMB study (N = 4,075 were used to identify predictors and barriers to postpartum care use. The LAMB study was a cross-sectional, population-based study that examined maternal and child health outcomes during the preconception, prenatal, and postpartum periods. Multivariable analyses identified low income, being separated/divorced and never married, trying hard to get pregnant or trying to prevent pregnancy, Medi-Cal insurance holders, and lack of prenatal care to be risk factors of postpartum care nonuse, while Hispanic ethnicity was protective. The most commonly reported barriers to postpartum care use were feeling fine, being too busy with the baby, having other things going on, and a lack of need. Findings from this study can inform the development of interventions targeting subgroups at risk for not obtaining postpartum care. Community education and improved access to care can further increase the acceptability of postpartum visits and contribute to improvements in women’s health. Postpartum care can serve as a gateway to engage underserved populations in the continuum of women’s health care.

  12. Update on the glomerular filtration barrier. (United States)

    Jarad, George; Miner, Jeffrey H


    The nephrology community lacks a unified view of protein sieving through the glomerular capillary wall. The glomerular capillary wall consists of three distinct but closely interacting layers: the fenestrated endothelium, with its glycocalyx; the podocytes, with their interdigitated foot processes and slit diaphragms; and the intervening glomerular basement membrane. Proteinuria is associated with abnormalities in any one layer, suggesting that each contributes to the glomerular filtration barrier (GFB). Proteinuria can also be induced in the context of a normal glomerular capillary wall. Here, we review some classic studies as well as some newer concepts and present competing hypotheses about the GFB. Two almost forgotten concepts have recently emerged. One group has challenged the exquisite selectivity of the GFB to albumin and suggested that proteinuria is the result of abnormal tubular uptake. There has also been a reemphasis on diffusion through the glomerular basement membrane as the driving force behind macromolecular filtration. New evidence suggests that the endothelial glycocalyx is an important charge-selective barrier. We suggest viewing the GFB as a dynamic rather than as a rigid barrier, requiring three healthy layers and a hemodynamic steady state. Multiple challenges to studying the endothelium, the tubular handling of albumin, and the role of hemodynamic forces will require new tools, new hypotheses, and open minds.

  13. Prohibitin Signaling at the Kidney Filtration Barrier. (United States)

    Ising, Christina; Brinkkoetter, Paul T


    The kidney filtration barrier consists of three well-defined anatomic layers comprising a fenestrated endothelium, the glomerular basement membrane (GBM) and glomerular epithelial cells, the podocytes. Podocytes are post-mitotic and terminally differentiated cells with primary and secondary processes. The latter are connected by a unique cell-cell contact, the slit diaphragm. Podocytes maintain the GBM and seal the kidney filtration barrier to prevent the onset of proteinuria. Loss of prohibitin-1/2 (PHB1/2) in podocytes results not only in a disturbed mitochondrial structure but also in an increased insulin/IGF-1 signaling leading to mTOR activation and a detrimental metabolic switch. As a consequence, PHB-knockout podocytes develop proteinuria and glomerulosclerosis and eventually loss of renal function. In addition, experimental evidence suggests that PHB1/2 confer additional, extra-mitochondrial functions in podocytes as they localize to the slit diaphragm and thereby stabilize the unique intercellular contact between podocytes required to maintain an effective filtration barrier.

  14. Two barriers for sodium in vascular endothelium? (United States)

    Oberleithner, Hans


    Vascular endothelium plays a key role in blood pressure regulation. Recently, it has been shown that a 5% increase of plasma sodium concentration (sodium excess) stiffens endothelial cells by about 25%, leading to cellular dysfunction. Surface measurements demonstrated that the endothelial glycocalyx (eGC), an anionic biopolymer, deteriorates when sodium is elevated. In view of these results, a two-barrier model for sodium exiting the circulation across the endothelium is suggested. The first sodium barrier is the eGC which selectively buffers sodium ions with its negatively charged prote-oglycans.The second sodium barrier is the endothelial plasma membrane which contains sodium channels. Sodium excess, in the presence of aldosterone, leads to eGC break-down and, in parallel, to an up-regulation of plasma membrane sodium channels. The following hypothesis is postulated: Sodium excess increases vascular sodium permeability. Under such con-ditions (e.g. high-sodium diet), day-by-day ingested sodium, instead of being readily buffered by the eGC and then rapidly excreted by the kidneys, is distributed in the whole body before being finally excreted. Gradually, the sodium overload damages the organism. PMID:22471931

  15. [Barrier creams in prevention of hand dermatoses]. (United States)

    Kurpiewska, Joanna; Liwkowicz, Jolanta


    Contact dermatitis is a common skin disease in the workplace and at home. Due to the high incidence of skin diseases the European Union countries have taken the activity to reduce or minimize this problem by the promotion of skin protection program, based on the application of skin protection measures - barrier creams and moisturizers. Definitions, reasons, mechanism of action and duration, application of methods, as well as the efficacy of using skin protection products in different workplaces are extensively reviewed in this article. Correctly matched barrier preparations protect against harmful factors and irritants, facilitating at the same time hand washing at the end of the working day, and together with the use of suitable non-irritating detergents and skin care products are important elements contributing to the prevention of occupational skin diseases. They shouldn't be used as a primary protection against high-risk substances. Numerous creams declared as the skin protection measures are on the market, so a careful selection of appropriate effective skin protecting barrier cream for the specific situations/environments is recommended.

  16. Barrier Coatings for Refractory Metals and Superalloys

    Energy Technology Data Exchange (ETDEWEB)

    SM Sabol; BT Randall; JD Edington; CJ Larkin; BJ Close


    In the closed working fluid loop of the proposed Prometheus space nuclear power plant (SNPP), there is the potential for reaction of core and plant structural materials with gas phase impurities and gas phase transport of interstitial elements between superalloy and refractory metal alloy components during service. Primary concerns are surface oxidation, interstitial embrittlement of refractory metals and decarburization of superalloys. In parallel with kinetic investigations, this letter evaluates the ability of potential coatings to prevent or impede communication between reactor and plant components. Key coating requirements are identified and current technology coating materials are reviewed relative to these requirements. Candidate coatings are identified for future evaluation based on current knowledge of design parameters and anticipated environment. Coatings were identified for superalloys and refractory metals to provide diffusion barriers to interstitial transport and act as reactive barriers to potential oxidation. Due to their high stability at low oxygen potential, alumina formers are most promising for oxidation protection given the anticipated coolant gas chemistry. A sublayer of iridium is recommended to provide inherent diffusion resistance to interstitials. Based on specific base metal selection, a thin film substrate--coating interdiffusion barrier layer may be necessary to meet mission life.

  17. The barrier within: endothelial transport of hormones. (United States)

    Kolka, Cathryn M; Bergman, Richard N


    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the tissue side of the blood vessel endothelium, suggesting that transport across this barrier can be rate limiting for hormone action. This transport can be regulated by altering the surface area of the blood vessel available for diffusion through to the underlying tissue or by the permeability of the endothelium. Many hormones are known to directly or indirectly affect the endothelial barrier, thus affecting their own distribution to their target tissues. Dysfunction of the endothelial barrier is found in many diseases, particularly those associated with the metabolic syndrome. The interrelatedness of hormones may help to explain why the cluster of diseases in the metabolic syndrome occur together so frequently and suggests that treating the endothelium may ameliorate defects in more than one disease. Here, we review the structure and function of the endothelium, its contribution to the function of hormones, and its involvement in disease.


    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek


    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.


    Energy Technology Data Exchange (ETDEWEB)

    G.H. Nieder-Westermann


    The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

  20. Computational modeling of the skin barrier. (United States)

    Naegel, Arne; Heisig, Michael; Wittum, Gabriel


    A simulation environment for the numerical calculation of permeation processes through human skin has been developed. In geometry models that represent the actual cell morphology of stratum corneum (SC) and deeper skin layers, the diffusive transport is simulated by a finite volume method. As reference elements for the corneocyte cells and lipid matrix, both three-dimensional tetrakaidecahedra and cuboids as well as two-dimensional brick-and-mortar models have been investigated. The central finding is that permeability and lag time of the different membranes can be represented in a closed form depending on model parameters and geometry. This allows a comparison of the models in terms of their barrier effectiveness at comparable cell sizes. The influence of the cell shape on the barrier properties has been numerically demonstrated and quantified. It is shown that tetrakaidecahedra in addition to an almost optimal surface-to-volume ratio also has a very favorable barrier-to-volume ratio. A simulation experiment was successfully validated with two representative test substances, the hydrophilic caffeine and the lipophilic flufenamic acid, which were applied in an aqueous vehicle with a constant dose. The input parameters for the simulation were determined in a companion study by experimental collaborators.

  1. Overcoming Branding Barriers in Nonprofit, Private Colleges and Universities (United States)

    Chyr, Fred


    Purpose: The purpose of this Delphi study was to explore the views of experts in the field of nonprofit private colleges and universities in the United States to define branding and identify current barriers to branding, to discover how those barriers can be overcome, and to determine what barriers to branding are likely to occur 5 years in the…

  2. An oncological view on the blood-testis barrier

    NARCIS (Netherlands)

    Bart, J; Groen, HJM; van der Graaf, WTA; Hollema, H; Hendrikse, NH; Vaalburg, W; Sleijfer, DT; de Vries, EGE

    The function of the blood-testis barrier is to protect germ cells from harmful influences; thus, it also impedes the delivery of chemotherapeutic drugs to the testis. The barrier has three components: first, a physicochemical barrier consisting of continuous capillaries, Sertoli cells in the tubular

  3. Barriers to and Facilitators of Health for Latina Undergraduate Students (United States)

    Mount, Jill


    Latina undergraduate students' barriers and facilitators of health are examined: Barriers to psychological health--separating from family, pressure to succeed, and racism; Barriers to physical health--lacking health insurance, and discomfort using campus sports facilities; and Facilitators of psychological health--membership in Latina student…

  4. Barriers and strategies for innovations entering BoP markets

    NARCIS (Netherlands)

    Kamp, L.M.; Ortt, J.R.; Harahap, B.


    Companies that bring a new product to the market or enter a new market with an existing product, come across a number of barriers that prevent large?scale diffusion. In order to circumvent or remove these barriers, they can adopt alternative strategies. This paper looks into these barriers and

  5. Method of producing a barrier in a thermally insulated container

    Energy Technology Data Exchange (ETDEWEB)

    Collins, M.H.; Le Hardy Guiton, J.D.


    The Netherlands' Shell Internationale Research Maatschappij B.V. has developed an essentially pinhole-free barrier for LNG storage/transport tanks. The barrier consists of layers of an expoxy-resin formulation and a glass-fiber material, applied in a special sequence to produce a barrier of superior quality.

  6. External Barriers Experienced by Gifted and Talented Girls and Women. (United States)

    Reis, Sally M.


    This article discusses current statistics about women and work and external barriers to achievement. Barriers include parental influences, media stereotypes, stereotyping in school, sexism in colleges and universities, and the burden of responsibilities females shoulder at home. Recommendations to help gifted girls address external barriers are…

  7. Navigating the barrier reef: QEE to successful restructuring. (United States)

    Hansen, M C; Jutting, J


    This article chronicles the barriers encountered as a multidisciplinary department undertook management restructuring. Barriers that are addressed include lack of a sense of urgency; confusion and fear regarding the changing roles of both staff and managers; insufficient development of coaching skills; and lack of alignment of performance appraisals, outcomes, and rewards. Insights gained and strategies to deal with these barriers are discussed.

  8. Classification of paraglacial barrier systems: coastal New England, USA.

    NARCIS (Netherlands)

    FitzGerald, D.M.; van Heteren, S.


    The New England coast harbours a wide variety of barrier forms, which we organize into six barrier-coastline types. The barriers develop in response to the relative importance of several spatially and temporally variable parameters, particularly antecedent topography and geology, sediment abundance

  9. Inflammation at the Blood–Brain Barrier in Multiple Sclerosis

    NARCIS (Netherlands)

    Mizee, M.R.; van Doorn, R.P.; Prat, A.; de Vries, H.E.; Fricker, G.; Ott, M.; Mahringer, A.


    The blood–brain barrier is specialized to function as a barrier to protect the central nervous system (CNS) by restricting entry of unwanted molecules and immune cells into the brain and inversely, to prevent CNS-born agents from reaching the systemic circulation. The blood–brain barrier

  10. Barriers to Asthma Management as Identified by School Nurses (United States)

    Quaranta, Judith E.; Spencer, Gale A.


    Asthma rates are increasing in children. School nurses have opportunities to care for children with asthma but need to overcome barriers impacting their ability to manage asthma in the school setting. This study (a) assessed barriers present in the school setting, (b) determined the impact of barriers on performance of asthma management behaviors,…

  11. SME's perceptions regarding strategic and structural entry barriers

    NARCIS (Netherlands)

    Lutz, Clemens; Kemp, Ron; Dijkstra, S. Gerhard


    Abstract Extant literature discusses a large number of different entry barriers that may hamper market efficiency or entrepreneurial activity. In practice several of these barriers cohere and stem from the same root. Factor analysis is used to identify the underlying dimensions of these barriers. 7

  12. 14 CFR 23.691 - Artificial stall barrier system. (United States)


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Artificial stall barrier system. 23.691... Construction Control Systems § 23.691 Artificial stall barrier system. If the function of an artificial stall... pitching motion. (d) Each system must be designed so that the artificial stall barrier can be quickly and...

  13. Adhesive flexible barrier film, method of forming same, and organic electronic device including same (United States)

    Blizzard, John Donald; Weidner, William Kenneth


    An adhesive flexible barrier film comprises a substrate and a barrier layer disposed on the substrate. The barrier layer is formed from a barrier composition comprising an organosilicon compound. The adhesive flexible barrier film also comprises an adhesive layer disposed on the barrier layer and formed from an adhesive composition. A method of forming the adhesive flexible barrier film comprises the steps of disposing the barrier composition on the substrate to form the barrier layer, disposing the adhesive composition on the barrier layer to form the adhesive layer, and curing the barrier layer and the adhesive layer. The adhesive flexible barrier film may be utilized in organic electronic devices.

  14. Blood-brain barrier disruption in CCL2 transgenic mice during pertussis toxin-induced brain inflammation

    DEFF Research Database (Denmark)

    Schellenberg, Angela E; Buist, Richard; Del Bigio, Marc R


    ABSTRACT: BACKGROUND: The chemokine CCL2 has an important role in the recruitment of inflammatory cells into the central nervous system (CNS). A transgenic mouse model that overexpresses CCL2 in the CNS shows an accumulation of leukocytes within the perivascular space surrounding vessels, which...

  15. Role of Caspase-3-Mediated Apoptosis in Chronic Caspase-3-Cleaved Tau Accumulation and Blood-Brain Barrier Damage in the Corpus Callosum after Traumatic Brain Injury in Rats. (United States)

    Glushakova, Olena Y; Glushakov, Andriy O; Borlongan, Cesar V; Valadka, Alex B; Hayes, Ronald L; Glushakov, Alexander V


    Traumatic brain injury (TBI) may be a significant risk factor for development of neurodegenerative disorders such as chronic traumatic encephalopathy (CTE), post-traumatic epilepsy (PTE), and Alzheimer's (AD) and Parkinson's (PD) diseases. Chronic TBI is associated with several pathological features that are also characteristic of neurodegenerative diseases, including tau pathologies, caspase-3-mediated apoptosis, neuroinflammation, and microvascular alterations. The goal of this study was to evaluate changes following TBI in cleaved-caspase-3 and caspase-3-cleaved tau truncated at Asp421, and their relationships to cellular markers potentially associated with inflammation and blood-brain (BBB) barrier damage. We studied astrocytes (glial fibrillary acidic protein [GFAP]), microglia (ionized calcium-binding adapter molecule 1 [Iba1]), BBB (endothelial barrier antigen [EBA]), and activated microglia/macrophages (cluster of differentiation 68 [CD68]). We employed immunohistochemistry at different time points from 24 h to 3 months after controlled cortical impact (CCI) injury in rats, with particular interest in white matter. The study demonstrated that CCI caused chronic upregulation of cleaved-caspase-3 in the white matter of the corpus callosum. Increases in cleaved-caspase-3 in the corpus callosum were accompanied by accumulation of caspase-3-cleaved tau, with increasing perivascular aggregation 3 months after CCI. Immunofluorescence experiments further showed cellular co-localization of cleaved-caspase-3 with GFAP and CD68 and its adjacent localization with EBA, suggesting involvement of apoptosis and neuroinflammation in mechanisms of delayed BBB and microvascular damage that could contribute to white matter changes. This study also provides the first evidence that evolving upregulation of cleaved-caspase-3 is associated with accumulation of caspase-3-cleaved tau following experimental TBI, thus providing new insights into potential common mechanisms mediated

  16. Legal and Regulatory Barriers to Reverse Innovation. (United States)

    Rowthorn, Virginia; Plum, Alexander J; Zervos, John

    Reverse innovation, or the importation of new, affordable, and efficacious models to high-income countries from the developing world, has emerged as a way to improve the health care system in the United States. Reverse innovation has been identified as a key emerging trend in global health systems in part because low-resourced settings are particularly good laboratories for low-cost/high-impact innovations that are developed out of necessity. A difficult question receiving scant attention is that of legal and regulatory barriers. The objective of this paper is to understand and elucidate the legal barriers faced by innovators bringing health interventions to the United States. Semistructured qualitative interviews were conducted with 9 key informants who have directly participated in the introduction of global health care approaches to the United States health system. A purposive sampling scheme was employed to identify participants. Phone interviews were conducted over one week in July 2016 with each participant and lasted an average of 35 minutes each. Purely legal barriers included questions surrounding tort liability, standard of care, and concerns around patient-administered self-care. Regulatory burdens included issues of international medical licensure, reimbursement, and task shifting and scope of work challenges among nonprofessionals (e.g. community health workers). Finally, perceived (i.e. not realized or experienced) legal and regulatory barriers to innovative modalities served as disincentives to bringing products or services developed outside of the United States to the United States market. Conflicting interests within the health care system, safety concerns, and little value placed on low-cost interventions inhibit innovation. Legal and regulatory barriers rank among, and contribute to, an anti-innovation atmosphere in healthcare for domestic and reverse innovators alike. Reverse innovation should be fostered through the thoughtful development of


    Energy Technology Data Exchange (ETDEWEB)

    Sandra Dalvit Dunn


    The overall objective of the effort was to develop and demonstrate an integrated methodology and field system to evaluate the integrity of in situ, impermeable barriers constructed in the vadose zone. An autonomous, remotely accessible, automatic monitoring and analysis system was designed and fabricated. It was thoroughly tested under field conditions, and was able to function as designed throughout the test period. Data inversion software was developed with enhanced capabilities over the previous prototype version, and integrated with the monitoring system for real time operation. Analytical simulations were performed to determine the inversion code's sensitivity to model parameters. Numerical simulations were performed to better understand how typical field conditions differ from the ideal model(s) which are used (or have been developed for use) in the inversion code and to further validate the flux limited forward model developed for use with the system. Results from the analytical and numerical assessment of the inversion code showed that the SEAtrace{trademark} approach could locate leaks within 0.4 to 1.2 m. Leak size determination was less accurate, but produced results within a factor of 3 to 8 for leaks in the 2.5 to 10 cm diameter range. The smallest engineered leak in the test 1.1 cm diameter, could be located but its size estimate was high by a factor of 30. Data analysis was performed automatically after each gas scan was completed, yielding results in less than thirty minutes, although the bulk of the results reported required post test data analysis to remove effects of high background concentrations. The field test of the integrated system was problematic, primarily due to unanticipated, unintentional leaks formed in the impermeable liner. The test facility constructed to proof the system was ambitious, initially having 11 engineered leaks of various dimensions that could be independently operated. While a great deal of care went into the

  18. The Infant Skin Barrier: Can We Preserve, Protect, and Enhance the Barrier?

    Directory of Open Access Journals (Sweden)

    Lorena S. Telofski


    Full Text Available Infant skin is different from adult in structure, function, and composition. Despite these differences, the skin barrier is competent at birth in healthy, full-term neonates. The primary focus of this paper is on the developing skin barrier in healthy, full-term neonates and infants. Additionally, a brief discussion of the properties of the skin barrier in premature neonates and infants with abnormal skin conditions (i.e., atopic dermatitis and eczema is included. As infant skin continues to mature through the first years of life, it is important that skin care products (e.g., cleansers and emollients are formulated appropriately. Ideally, products that are used on infants should not interfere with skin surface pH or perturb the skin barrier. For cleansers, this can be achieved by choosing the right type of surfactant, by blending surfactants, or by blending hydrophobically-modified polymers (HMPs with surfactants to increase product mildness. Similarly, choosing the right type of oil for emollients is important. Unlike some vegetable oils, mineral oil is more stable and is not subject to oxidation and hydrolysis. Although emollients can improve the skin barrier, more studies are needed to determine the potential long-term benefits of using emollients on healthy, full-term neonates and infants.

  19. Permeable bio-reactive barriers for hydrocarbon remediation in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Mumford, K.A.; Stevens, G.W.; Gore, D.B. [Melbourne Univ., Victoria (Australia). Dept. of Chemical and Biomoleculuar Engineering, Particulate Fluids Processing Centre; Snape, I.; Rayner, J.L. [Australian Antarctic Div., Kingston, Tasmania (Australia); Gore, D.B. [Macquarie Univ., Sydney, NSW (Australia). Dept. of Environmental Science


    This study assessed the performance of a permeable bio-reactive barrier designed to treat contaminated water. The bio-reactive barrier was installed at a fuel spill site located in the Windmill Islands, Antarctica. A funnel and gate design was used to prevent contaminant migration beyond the barrier location as well as to ensure controlled nutrient delivery. The study also investigated the performance of the bio-reactive barrier in regions with freeze-thaw conditions. The 4-year project was also conducted to assess optimal conditions for enhancing the barrier's ability to degrade hydrocarbons.

  20. Mechanisms of microbial traversal of the blood-brain barrier. (United States)

    Kim, Kwang Sik


    Central nervous system (CNS) infections continue to be an important cause of morbidity and mortality. Microbial invasion and traversal of the blood-brain barrier is a prerequisite for CNS infections. Pathogens can cross the blood-brain barrier transcellularly, paracellularly and/or in infected phagocytes (the so-called Trojan-horse mechanism). Consequently, pathogens can cause blood-brain barrier dysfunction, including increased permeability, pleocytosis and encephalopathy. A more complete understanding of the microbial-host interactions that are involved in microbial traversal of the blood-brain barrier and the associated barrier dysfunction should help to develop new strategies to prevent CNS infections.

  1. Large magnetocurrents in double-barrier tunneling transistors

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.H. [Nano Device Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Physics, Korea University, Chochiwon 339-700 (Korea, Republic of); Jun, K.-I. [Nano Device Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Shin, K.-H. [Nano Device Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Park, S.Y. [Department of Physics, Korea University, Chochiwon 339-700 (Korea, Republic of); Hong, J.K. [Department of Physics, Korea University, Chochiwon 339-700 (Korea, Republic of); Rhie, K. [Department of Physics, Korea University, Chochiwon 339-700 (Korea, Republic of)]. E-mail:; Lee, B.C. [Department of Physics, Inha University, Incheon (Korea, Republic of)


    Magnetic tunneling transistors (MTT) with double tunneling barriers are fabricated. The structure of the transistor is AFM/FM/I/FM/I/FM/AFM, and ferromagnetic layers serve as the emitter, base and collector. This double-barrier tunneling transistor (DBTT) has an advantage of controlling the potential between the base and collector, compared to the Schottky-barrier-based base and collector of MTT. We found that the collector current density of DBTT is at least 10{sup 3} times larger than that of conventional MTT, since tunneling through AlO{sub x} barrier provides much larger current density than that through Schottky barrier.

  2. Barrier Coverage for 3D Camera Sensor Networks. (United States)

    Si, Pengju; Wu, Chengdong; Zhang, Yunzhou; Jia, Zixi; Ji, Peng; Chu, Hao


    Barrier coverage, an important research area with respect to camera sensor networks, consists of a number of camera sensors to detect intruders that pass through the barrier area. Existing works on barrier coverage such as local face-view barrier coverage and full-view barrier coverage typically assume that each intruder is considered as a point. However, the crucial feature (e.g., size) of the intruder should be taken into account in the real-world applications. In this paper, we propose a realistic resolution criterion based on a three-dimensional (3D) sensing model of a camera sensor for capturing the intruder's face. Based on the new resolution criterion, we study the barrier coverage of a feasible deployment strategy in camera sensor networks. Performance results demonstrate that our barrier coverage with more practical considerations is capable of providing a desirable surveillance level. Moreover, compared with local face-view barrier coverage and full-view barrier coverage, our barrier coverage is more reasonable and closer to reality. To the best of our knowledge, our work is the first to propose barrier coverage for 3D camera sensor networks.

  3. Barrier Coverage for 3D Camera Sensor Networks (United States)

    Wu, Chengdong; Zhang, Yunzhou; Jia, Zixi; Ji, Peng; Chu, Hao


    Barrier coverage, an important research area with respect to camera sensor networks, consists of a number of camera sensors to detect intruders that pass through the barrier area. Existing works on barrier coverage such as local face-view barrier coverage and full-view barrier coverage typically assume that each intruder is considered as a point. However, the crucial feature (e.g., size) of the intruder should be taken into account in the real-world applications. In this paper, we propose a realistic resolution criterion based on a three-dimensional (3D) sensing model of a camera sensor for capturing the intruder’s face. Based on the new resolution criterion, we study the barrier coverage of a feasible deployment strategy in camera sensor networks. Performance results demonstrate that our barrier coverage with more practical considerations is capable of providing a desirable surveillance level. Moreover, compared with local face-view barrier coverage and full-view barrier coverage, our barrier coverage is more reasonable and closer to reality. To the best of our knowledge, our work is the first to propose barrier coverage for 3D camera sensor networks. PMID:28771167

  4. How to break the barriers to climate awareness

    DEFF Research Database (Denmark)

    Kemp, Peter


    In this paper is provided a philosophical analysis of the cognitive barriers that may block the individual citizen’s acknowledgement of a personal responsibility to engage in climate responsible behaviour. The authors distinguish between two types of cognitive barriers; the physical barriers, tha......, that are associated with the way we gain knowledge about climate change and the physical world state; and the psychological barriers, that arise from ideas about ourselves and the nature that surrounds us.......In this paper is provided a philosophical analysis of the cognitive barriers that may block the individual citizen’s acknowledgement of a personal responsibility to engage in climate responsible behaviour. The authors distinguish between two types of cognitive barriers; the physical barriers...

  5. Barrier transgression driven by aeolian processes along the Portuguese coast (United States)

    Costas, Susana; Ferreira, Óscar; Roelvink, Dano


    Coastal barriers around the world developed following sea level stabilization about 7000 years ago. Along the Southwestern European coast, this fact was largely supported by recent works exploring the sedimentary record of coastal lagoons and estuaries. However, direct evidences of barrier evolution/age obtained from the actual coastal barriers are rare, limiting our understanding about the dynamics and life time of these systems at long time scales. Here, we reconstruct the evolution of three coastal barriers located along the western Portuguese coast, determining their age, trends and life cycles. For that, we integrate information (stratigraphy and ages) from different coastal deposits indicative of major shifts on evolutionary trends, including published and unpublished data. Examined beach deposits set the age of the explored sand barriers between 6400 and 300 years ago, suggesting the coexistence of very mature and very recent coastal barriers. In addition, the results document the occurrence of transgressive dunefields with ages older than the preserved coastal barriers, supporting the existence of former barriers from which the dunes could derive and migrate inland. The latter suggests the occurrence of episodes of barrier building and shoreline progradation alternating with episodes of inland migration of transgressive dunefields and thus barrier rollover. Resultant trends are carefully examined to identify the major factors driving barrier evolution, with special attention to climate variability and local boundary conditions. Indeed, the episodic response of the explored sand barriers provides indications for shifting wave and wind conditions as a consequence of climate variability. Additionally, inter-site comparison provides significant insights into regional trends and allows rating the identified factors, based on the degree of direct influence over the evolution of the coast. In this regard, the exposure to wind and wave climate, usually linked to

  6. Pharmacogenetics in Europe: barriers and opportunities. (United States)

    Gurwitz, D; Zika, E; Hopkins, M M; Gaisser, S; Ibarreta, D


    This paper reviews the current situation in the field of pharmacogenetics/pharmacogenomics (PGx) in Europe. High expectations surrounding the clinical application of PGx remain largely unmet, as only a limited number of such applications have actually reached the market and clinical practice. Thus, the potential impact of PGx-based diagnostics on healthcare and its socio-economic implications are still unclear. With the aim of shedding some light on these uncertainties, the Institute for Prospective Technological Studies (IPTS) of the European Commission's Joint Research Centre (JRC) has conducted a review of the 'state of the art' and a further analysis on the use of pharmacogenetics diagnostics for preventing toxic drug reactions and improving drug efficacy in Europe. The paper presents highlights from the JRC-IPTS studies and discusses possibilities for improving translation of PGx research in Europe by comparing some experiences in the USA. We also illustrate the related barriers for the clinical uptake of PGx in Europe with specific case-studies. Most of the barriers identified extend beyond the European context. This reflects the global problems of scarcity of data demonstrating proven clinical validity or utility and favorable cost-effectiveness studies to support the clinical application of PGx diagnostic tests in the clinical setting. Another key barrier is the lack of incentives for the private sector to invest in the development and licensing of PGx diagnostic tests for improving the safety and efficacy of out-of-patent drugs. It therefore seems that one key aspect where policy can affect the clinical uptake of PGx is via sustaining large-scale industry-academia collaborations for developing and proving the utility of PGx diagnostics. Copyright 2009 S. Karger AG, Basel.

  7. Permeation barrier for lightweight liquid hydrogen tanks

    Energy Technology Data Exchange (ETDEWEB)

    Schultheiss, D.


    For the future usage of hydrogen as an automotive fuel, its on-board storage is crucial. One approach is the storage of liquid hydrogen (LH2, 20 K) in double-walled, vacuum insulated tanks. The introduction of carbon fiber reinforced plastics (CFRP) as structural material enables a high potential of reducing the weight in comparison to the state-of-the-art stainless steel tanks. The generally high permeability of hydrogen through plastics, however, can lead to long-term degradation of the insulating vacuum. The derived objective of this dissertation was to find and apply an adequate permeation barrier (liner) on CFRP. The investigated liners were either foils adhered on CFRP specimens or coatings deposited on CFRP specimens. The coatings were produced by means of thermal spraying, metal plating or physical vapor deposition (PVD). The materials of the liners included Al, Au, Cu, Ni and Sn as well as stainless steel and diamond-like carbon. The produced liners were tested for their permeation behavior, thermal shock resistance and adherence to the CFRP substrate. Additionally, SEM micrographs were used to characterize and qualify the liners. The foils, although being a good permeation barrier, adhered weakly to the substrate. Furthermore, leak-free joining of foil segments is a challenge still to be solved. The metal plating liners exhibited the best properties. For instance, no permeation could be detected through a 50 {mu}m thick Cu coating within the accuracy of the measuring apparatus. This corresponds to a reduction of the permeation gas flow by more than factor 7400 compared to uncoated CFRP. In addition, the metal platings revealed a high adherence and thermal shock resistance. The coatings produced by means of thermal spraying and PVD did not show a sufficient permeation barrier effect. After having investigated the specimens, a 170 liter CFRP tank was fully coated with 50 {mu}m Cu by means of metal plating. (orig.)

  8. Boosters and barriers for direct cardiac reprogramming. (United States)

    Talkhabi, Mahmood; Zonooz, Elmira Rezaei; Baharvand, Hossein


    Heart disease is currently the most significant cause of morbidity and mortality worldwide, which accounts for approximately 33% of all deaths. Recently, a promising and alchemy-like strategy has been developed called direct cardiac reprogramming, which directly converts somatic cells such as fibroblasts to cardiac lineage cells such as cardiomyocytes (CMs), termed induced CMs or iCMs. The first in vitro cardiac reprogramming study, mediated by cardiac transcription factors (TFs)-Gata4, Tbx5 and Mef2C-, was not enough efficient to produce an adequate number of fully reprogrammed, functional iCMs. As a result, numerous combinations of cardiac TFs exist for direct cardiac reprogramming of mouse and human fibroblasts. However, the efficiency of direct cardiac reprogramming remains low. Recently, a number of cellular and molecular mechanisms have been identified to increase the efficiency of direct cardiac reprogramming and the quality of iCMs. For example, microgrooved substrate, cardiogenic growth factors [VEGF, FGF, BMP4 and Activin A], and an appropriate stoichiometry of TFs boost the direct cardiac reprogramming. On the other hand, serum, TGFβ signaling, activators of epithelial to mesenchymal transition, and some epigenetic factors (Bmi1 and Ezh2) are barriers for direct cardiac reprogramming. Manipulating these mechanisms by the application of boosters and removing barriers can increase the efficiency of direct cardiac reprogramming and possibly make iCMs reliable for cell-based therapy or other potential applications. In this review, we summarize the latest trends in cardiac TF- or miRNA-based direct cardiac reprogramming and comprehensively discuses all molecular and cellular boosters and barriers affecting direct cardiac reprogramming. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. Ceramides and barrier function in healthy skin

    DEFF Research Database (Denmark)

    Mutanu Jungersted, Jakob; Hellgren, Lars; Høgh, Julie Kaae


    Lipids in the stratum corneum are key components in the barrier function of the skin. Changes in lipid composition related to eczematous diseases are well known, but limited data are available on variations within healthy skin. The objective of the present study was to compare ceramide subgroups...... and ceramide/cholesterol ratios in young, old, male and female healthy skin. A total of 55 participants with healthy skin was included in the study. Lipid profiles were correlated with transepidermal water loss and with information on dry skin from a questionnaire including 16 people. No statistically...

  10. The blood-brain barrier in psychoneuroimmunology. (United States)

    Banks, William A


    The term ''psychoneuroimmunology'' connotes separate compartments that interact. The blood-brain barrier (BBB) is both the dividing line, physical and physiologic, between the immune system and the central nervous system (CNS) and the locale for interaction. The BBB restricts unregulated mixing of immune substances in the blood with those in the CNS, directly transports neuroimmune-active substances between the blood and CNS, and itself secretes neuroimmune substances. These normal functions of the BBB can be altered by neuroimmune events. As such, the BBB is an important conduit in the communication between the immune system and the CNS.

  11. Antimicrobial Peptides, Infections and the Skin Barrier

    DEFF Research Database (Denmark)

    Clausen, Maja Lisa; Agner, Tove


    and transported to the stratum corneum, where they play a vital role in the first line of defense against potential pathogens. Numerous AMPs exist, and they have a broad antibiotic-like activity against bacteria, fungi and viruses. They also act as multifunctional effector molecules, linking innate and adaptive...... immune responses. AMPs play an essential part in maintaining an optimal and functional skin barrier - not only by direct killing of pathogens, but also by balancing immune responses and interfering in wound healing, cell differentiation, reepithelialization and their synergistic interplay with the skin...

  12. Is secrecy a barrier for intelligence studies?

    Directory of Open Access Journals (Sweden)

    Franck BULINGE


    Full Text Available This articles aims to highlight the issues, challenges and constraints of intelligence studies considering the notion of cryptic space, understood as a “secret space of communication within which the individual is exempt from the requirements and constraints of secrecy “(Bulinge, 2002. This article aims to highlight two ways for social research in the field of intelligence. In particular, we will show that the multiple dimensions of information can be addressed by researchers without prejudice to the constraints related to the preservation of secrecy. In other words, secrecy as a part of intelligence is not a barrier for intelligence studies.

  13. Breaking Barriers in Polymer Additive Manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Love, Lonnie J [ORNL; Duty, Chad E [ORNL; Post, Brian K [ORNL; Lind, Randall F [ORNL; Lloyd, Peter D [ORNL; Kunc, Vlastimil [ORNL; Peter, William H [ORNL; Blue, Craig A [ORNL


    Additive Manufacturing (AM) enables the creation of complex structures directly from a computer-aided design (CAD). There are limitations that prevent the technology from realizing its full potential. AM has been criticized for being slow and expensive with limited build size. Oak Ridge National Laboratory (ORNL) has developed a large scale AM system that improves upon each of these areas by more than an order of magnitude. The Big Area Additive Manufacturing (BAAM) system directly converts low cost pellets into a large, three-dimensional part at a rate exceeding 25 kg/h. By breaking these traditional barriers, it is possible for polymer AM to penetrate new manufacturing markets.

  14. Periodontal maintenance--overcoming the barriers. (United States)

    Fardal, Øystein


    Periodontal maintenance therapy is the most important stage of periodontal treatment, yet compliance is low. Overcoming the barriers associated with the low compliance involves a complex set of problems relating to the patient, the clinician and the interactions between them. It is therefore important to create a periodontal maintenance treatment programme which takes into consideration the needs of each individual patient. In addition, regional variations and differences in practice profiles are also factors to be accommodated in a maintenance programme. Good co-operation between the referring dentist and the specialist is required when recommendations are made to the patient regarding maintenance therapy.

  15. Novel hybrid polymeric materials for barrier coatings (United States)

    Pavlacky, Erin Christine

    Polymer-clay nanocomposites, described as the inclusion of nanometer-sized layered silicates into polymeric materials, have been widely researched due to significant enhancements in material properties with the incorporation of small levels of filler (1--5 wt.%) compared to conventional micro- and macro-composites (20--30 wt.%). One of the most promising applications for polymer-clay nanocomposites is in the field of barrier coatings. The development of UV-curable polymer-clay nanocomposite barrier coatings was explored by employing a novel in situ preparation technique. Unsaturated polyesters were synthesized in the presence of organomodified clays by in situ intercalative polymerization to create highly dispersed clays in a precursor resin. The resulting clay-containing polyesters were crosslinked via UV-irradiation using donor-acceptor chemistry to create polymer-clay nanocomposites which exhibited significantly enhanced barrier properties compared to alternative clay dispersion techniques. The impact of the quaternary alkylammonium organic modifiers, used to increase compatibility between the inorganic clay and organic polymer, was studied to explore influence of the organic modifier structure on the nanocomposite material properties. By incorporating just the organic modifiers, no layered silicates, into the polyester resins, reductions in film mechanical and thermal properties were observed, a strong indicator of film plasticization. An alternative in situ preparation method was explored to further increase the dispersion of organomodified clay within the precursor polyester resins. In stark contrast to traditional in situ polymerization methods, a novel "reverse" in situ preparation method was developed, where unmodified montmorillonite clay was added during polyesterification to a reaction mixture containing the alkylammonium organic modifier. The resulting nanocomposite films exhibited reduced water vapor permeability and increased mechanical properties

  16. An extreme breaching of a barrier spit: insights on large breach formation and its impact on barrier dynamics (United States)

    Iulian Zăinescu, Florin; Vespremeanu-Stroe, Alfred; Tătui, Florin


    In this study, we document a case of exceptionally large natural breaching of a sandy spit (Sacalin barrier, Danube delta) using Lidar data and satellite imagery, annual (and seasonal) surveys of topography and bathymetry on successive cross-barrier profiles, and hourly datasets of wind and waves. The breach morphology and dynamics was monitored and described from its inception to closure, together with its impact on the adjoining features (upper shoreface, back-barrier lagoon, downdrift coast) and on the local sediment budgets. Breaching is first observed to occur on a beach-length of 0.5 km in April 2012 and two years later reached 3.5 km (May 2014). The barrier translates to a recovery stage dominated by continuous back-barrier deposition through subaqueous cross-breach sediment transport. Soon, the barrier widening triggers a negative feedback which limits the back-barrier sediment transfer. As a result, back-barrier deposition decreases whilst the barrier aggradation through overwash becomes more frequent. The event was found to be a natural experiment which switched the barrier's decadal evolution from low cross-shore transport to high cross-shore transport over the barrier. Although previously considered as constant, the cross-shore transport recorded during the large breach lifespan is an order of magnitude larger than in the non-breach period. 3 x 106 m3 of sediment were deposited in three years which is equivalent to the modelled longshore transport in the region. Nevertheless, the sediment circuits are more complex involving exchanges with the upper shoreface, as indicated by the extensive erosion down to -4m. In the absence of tides, the Sacalin breach closed naturally in 3 years and brings a valuable contribution on how breaches may evolve, as only limited data has been internationally reported until now. The very high deposition rate of sediment in the breach is a testimony of the high sediment volumes supplied by the longshore transport and the high

  17. Fluids and barriers of the CNS establish immune privilege by confining immune surveillance to a two-walled castle moat surrounding the CNS castle. (United States)

    Engelhardt, Britta; Coisne, Caroline


    Neuronal activity within the central nervous system (CNS) strictly depends on homeostasis and therefore does not tolerate uncontrolled entry of blood components. It has been generally believed that under normal conditions, the endothelial blood-brain barrier (BBB) and the epithelial blood-cerebrospinal fluid barrier (BCSFB) prevent immune cell entry into the CNS. This view has recently changed when it was realized that activated T cells are able to breach the BBB and the BCSFB to perform immune surveillance of the CNS. Here we propose that the immune privilege of the CNS is established by the specific morphological architecture of its borders resembling that of a medieval castle. The BBB and the BCSFB serve as the outer walls of the castle, which can be breached by activated immune cells serving as messengers for outside dangers. Having crossed the BBB or the BCSFB they reach the castle moat, namely the cerebrospinal fluid (CSF)-drained leptomeningeal and perivascular spaces of the CNS. Next to the CNS parenchyma, the castle moat is bordered by a second wall, the glia limitans, composed of astrocytic foot processes and a parenchymal basement membrane. Inside the castle, that is the CNS parenchyma proper, the royal family of sensitive neurons resides with their servants, the glial cells. Within the CSF-drained castle moat, macrophages serve as guards collecting all the information from within the castle, which they can present to the immune-surveying T cells. If in their communication with the castle moat macrophages, T cells recognize their specific antigen and see that the royal family is in danger, they will become activated and by opening doors in the outer wall of the castle allow the entry of additional immune cells into the castle moat. From there, immune cells may breach the inner castle wall with the aim to defend the castle inhabitants by eliminating the invading enemy. If the immune response by unknown mechanisms turns against self, that is the castle

  18. Understanding and predicting decadal behaviour of sandy barriers (United States)

    Cooper, Andrew


    Developing geological/morphodynamic models of geomorphic systems involves the identification of common attributes from numerous examples or case studies and the distillation away of local variability. Barrier and barrier island systems share many common features, but there is a wide range of variability that strongly influences how they behave at historical timescales. Much morphodynamic modelling is centred on the relationship between dynamic driving forces on the one hand, and geomorphic response on the other. Some models take into account the feedback that exists between these. Less often considered are factors related to sediment volume and supply, underlying geology and the geological setting, and self-organization. Consideration of 'unusual' barrier island systems, where one or more of these factors is particularly important, highlights their role in barrier behaviour. Barrier islands on bedrock in Scotland demonstrate a primary control on evolution of antecedent topography. The low volume of sand in barrier islands in Chesapeake Bay is primarily responsible for very rapid migration rates. Episodic fluvial sediment supply to some South African barriers controls their historical scale behaviour. The high volume of sand in southern Brazil Barriers is a major constraint on their morphological evolution. These and other examples highlight the importance of factors that are often regarded as 'noise' in morphodynamic modelling. The nature of 'local variability' in barriers and barrier islands is diverse, but its important, and even dominant role in their evolution, urges caution in the application of generic modellling approaches in predicting future shoreline behavior.

  19. Consensus on Bridges for Barriers to Insulin Therapy. (United States)

    Kalra, Sanjay; Ghosal, Samit; Shah, Parag


    Insulin is an effective, safe and well-tolerated drug for glycaemic control. However, there are significant barriers to its use. This consensus statement aims to define these barriers and suggest bridges to overcome them. The consensus statements are based upon deliberations of a meeting held at New Delhi, India on 20 August 2016. The expert group committee reviewed various barriers to insulin use and categorized them into various categories: patient/community-related, physician-related and drug-related. The committee further proposed recommendations, based on published literature and their clinical experience, to address each of these barriers. Barriers (and bridges) can be classified as patient/community, physician/provider, and drug/device. Patient and physician barriers can further be categorized as those related to perceived inadequacy, perceived high cost, and perceived lack of benefit. Drug and device barriers can similarly be classified as those linked with perceived inadequacy, perceived high cost, and perceived lack of tolerability. Such a classification allows diabetes care providers to build appropriate bridges, which in turn facilitate timely insulin usage. Patient related barriers can be bridged by education, support and counselling. Use of modern insulin regimes and social marketing can address barriers related to perceived cost and lack of benefit. Physician related barriers can be resolved by training on various aspects of diabetes care. This will also help to break drug and device barriers, by ensuring appropriate choice of regimes, preparations and delivery devices. The consensus statements provide an easily understandable taxonomic structure of barriers to insulin use. By using a reader-friendly rubric, and by focusing on bridges (rather than barriers alone), it promotes a proactive and positive approach to diabetes management. The consensus statement should serve as a useful pedagogic and clinical tool for diabetes care professionals, and

  20. Testing of isolation barrier sealing surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Graves, C.E.


    Isolation barrier doors are to be installed in the 105KE and 105KW basins as part of the 1994 unreviewed safety question (USQ) resolution plan to isolate the fuel storage basin from the fuel discharge chute. Included in this installation is the placement of new sealing surfaces for the barriers by affixing stainless steel plates to existing carbon steel angle bars with a specially formulated epoxy adhesive/sealant material. The sealant is a two-part component consisting of an epoxy resin (the condensation product of bisphenol A and epichlorohydrin) and a curing agent (a proprietary cycloaliphatic polyamine). The sealant is solvent free (complying with air pollution regulations) and capable of withstanding the surrounding radiation fields over an estimated 15-year service life. The epoxy sealant experiences negligible water damage partly because of its hydrophobic (water-repelling) nature. With bond tensile strengths measured at greater than 862 kPa (125 lbf/in{sup 2}), the epoxy sealant is judged acceptable for its intended application. The four-hour pot life of the epoxy sealant provides sufficient time to apply the epoxy, examine the epoxy bead for continuity, and position the stainless steel sealing plates.

  1. Neutrophils Compromise Retinal Pigment Epithelial Barrier Integrity

    Directory of Open Access Journals (Sweden)

    Jiehao Zhou


    Full Text Available We hypothesized that neutrophils and their secreted factors mediate breakdown of the integrity of the outer blood-retina-barrier by degrading the apical tight junctions of the retinal pigment epithelium (RPE. The effect of activated neutrophils or neutrophil cell lysate on apparent permeability of bovine RPE-Choroid explants was evaluated by measuring [H] mannitol flux in a modified Ussing chamber. The expression of matrix metalloproteinase- (MMP- 9 in murine peritoneal neutrophils, and the effects of neutrophils on RPE tight-junction protein expression were assessed by confocal microscopy and western blot. Our results revealed that basolateral incubation of explants with neutrophils decreased occludin and ZO-1 expression at 1 and 3 hours and increased the permeability of bovine RPE-Choroid explants by >3-fold (P<.05. Similarly, basolateral incubation of explants with neutrophil lysate decreased ZO-1 expression at 1 and 3 hours (P<.05 and increased permeability of explants by 75%. Further, we found that neutrophils prominently express MMP-9 and that incubation of explants with neutrophils in the presence of anti-MMP-9 antibody inhibited the increase in permeability. These data suggest that neutrophil-derived MMP-9 may play an important role in disrupting the integrity of the outer blood-retina barrier.

  2. Celiac Disease: Role of the Epithelial Barrier. (United States)

    Schumann, Michael; Siegmund, Britta; Schulzke, Jörg D; Fromm, Michael


    In celiac disease (CD) a T-cell-mediated response to gluten is mounted in genetically predisposed individuals, resulting in a malabsorptive enteropathy histologically highlighted by villous atrophy and crypt hyperplasia. Recent data point to the epithelial layer as an under-rated hot spot in celiac pathophysiology to date. This overview summarizes current functional and genetic evidence on the role of the epithelial barrier in CD, consisting of the cell membranes and the apical junctional complex comprising sealing as well as ion and water channel-forming tight junction proteins and the adherens junction. Moreover, the underlying mechanisms are discussed, including apoptosis of intestinal epithelial cells, biology of intestinal stem cells, alterations in the apical junctional complex, transcytotic uptake of gluten peptides, and possible implications of a defective epithelial polarity. Current research is directed toward new treatment options for CD that are alternatives or complementary therapeutics to a gluten-free diet. Thus, strategies to target an altered epithelial barrier therapeutically also are discussed.

  3. Child Abuse Reporting Barriers: Iranian Nurses' Experiences. (United States)

    Borimnejad, Leili; Khoshnavay Fomani, Fatemeh


    Although in many countries child abuse reporting is mandated, Iranian nurses report abused cases voluntary. Some of the cases are reported to the police and others are referred to welfare organizations or other non-governmental organizations. Absence of a uniform reporting system along with a lack of legal support in the specific cultural context of Iran has resulted challenges for the reporters of child abuse. The aim of this study was to explore the Iranian nurses' experiences of reporting child abuse as well as to explore the existing barriers. A qualitative study with conventional content analysis was conducted to explore the barriers of reporting child abuse. Individual interviews between 30 and 45 minutes in duration were conducted with a purposive sample of 16 nurses with direct experience of dealing with children who had been abused. Graneheim and Lundman's method was used for data analysis. The data were classified to five themes including "knowledge deficit", "previous unpleasant experiences about child abuse reporting", "ethical challenges"," legal challenges" and "cultural beliefs". According to the findings, enhancement of nurses and public knowledge about child abuse, legal issues and jurisprudence along with legislation of clear and simple laws, are mandatory to protect abused children in Iran.

  4. Child Abuse Reporting Barriers: Iranian Nurses’ Experiences (United States)

    Borimnejad, Leili; Khoshnavay Fomani, Fatemeh


    Background: Although in many countries child abuse reporting is mandated, Iranian nurses report abused cases voluntary. Some of the cases are reported to the police and others are referred to welfare organizations or other non-governmental organizations. Absence of a uniform reporting system along with a lack of legal support in the specific cultural context of Iran has resulted challenges for the reporters of child abuse. Objectives: The aim of this study was to explore the Iranian nurses’ experiences of reporting child abuse as well as to explore the existing barriers. Patients and Methods: A qualitative study with conventional content analysis was conducted to explore the barriers of reporting child abuse. Individual interviews between 30 and 45 minutes in duration were conducted with a purposive sample of 16 nurses with direct experience of dealing with children who had been abused. Graneheim and Lundman’s method was used for data analysis. Results: The data were classified to five themes including “knowledge deficit”, “previous unpleasant experiences about child abuse reporting”, “ethical challenges”,” legal challenges” and “cultural beliefs”. Conclusions: According to the findings, enhancement of nurses and public knowledge about child abuse, legal issues and jurisprudence along with legislation of clear and simple laws, are mandatory to protect abused children in Iran. PMID:26430523

  5. Nurses' Psychosocial Barriers to Suicide Risk Management

    Directory of Open Access Journals (Sweden)

    Sharon Valente


    Full Text Available Suicide remains a serious health care problem and a sentinel event tracked by The Joint Commission. Nurses are pivotal in evaluating risk and preventing suicide. Analysis of nurses' barriers to risk management may lead to interventions to improve management of suicidal patients. These data emerged from a random survey of 454 oncology nurses' attitudes, knowledge of suicide, and justifications for euthanasia. Instruments included a vignette of a suicidal patient and a suicide attitude questionnaire. Results. Psychological factors (emotions, unresolved grief, communication, and negative judgments about suicide complicate the nurse's assessment and treatment of suicidal patients. Some nurses (=122 indicated that euthanasia was never justified and 11 were unsure of justifications and evaluated each case on its merits. Justifications for euthanasia included poor symptom control, poor quality of life, incurable illness or permanent disability, terminal illness, and terminal illness with inadequate symptom control or impending death, patient autonomy, and clinical organ death. The nurses indicated some confusion and misconceptions about definitions and examples of euthanasia, assisted suicide, and double effect. Strategies for interdisciplinary clinical intervention are suggested to identify and resolve these psychosocial barriers.

  6. Barriers to Garden Visitation in Children's Hospitals. (United States)

    Pasha, Samira


    This study aimed to identify barriers to use of outdoor spaces in Texas pediatric healthcare facilities. Available research on hospital healing gardens and outdoor spaces has indicated that despite several health benefits of garden visitation for staff, patients, and family members, these amenities are not being used to their fullest capacity. Previous researchers have recommended design features such as comfortable seats and adequate shade to increase garden visitation in healthcare setting. However no quantitative data have demonstrated significance of correlation between presence of these design features and garden use. The present study served to statistically support design guidelines suggested by previous researchers and introduce new guidelines. Site visits and surveys were conducted in five green outdoor spaces in three pediatric hospitals in east Texas. Hospital visitors, family members, and staff responded to questions concerning barriers to garden visitation, their visitation habits, and satisfaction with the garden features. The study was reviewed and approved by Institutional Review Boards of the relevant hospitals and academic institutions. A negative significant correlation was found between staff garden use and dissatisfaction with quality of seats and poor shade. While quality of seats didn't impact visitor and family member garden visitation, a significant negative correlation was found between poor shade and their garden use. The study served to statistically support previous design suggestions for hospital gardens, and introduced new design guidelines. Design recommendations include functionality, visibility, accessibility, exclusivity, and availability of shade and seats. Design process, evidence-based design, healing environments, hospital.

  7. Rare disease research: Breaking the privacy barrier

    Directory of Open Access Journals (Sweden)

    Deborah Mascalzoni


    Full Text Available Due to the few patients affected, rare disease research has to count on international registries to exist in order to produce significant research outputs. Data sharing of registries is therefore a unique resource to allow rare disease research to flourish and any lost data will jeopardize the quality of an already extremely difficult research. The rules usually applied to research such as the right to withdraw or the need for specific consent for every use of data can be detrimental in order to get effective results. Privacy rights regulated through traditional informed consent mechanisms have been regarded as a major barrier in order to effectively share data worldwide. Some authors argue that this barrier hampers results that could be beneficial to the patients so that another right will be overstated: the right to quality healthcare. We argue in this paper that privacy has been often interpreted just one-sided as the right to secrecy but it can entail another meaning: the right to manage one's own private sphere. Managing it pertains, not only to the right to deny access, but also to the right to grant access. At the same time research on patient participation and transparency shows that new forms of IT-based informed consent can provide a good balance between the right of individuals to be in control of their data and the opportunity for science to pursue international research.

  8. Mucus as a barrier to lipophilic drugs. (United States)

    Sigurdsson, Hakon H; Kirch, Julian; Lehr, Claus-Michael


    Mucus is a complex hydrogel, comprising glycoproteins, lipids, salts, DNA, enzymes and cellular debris, covering many epithelial surfaces in the human body. Once secreted, mucin forms a barrier to protect the underlying tissues against the extracellular environment. Mucus can therefore adversely affect the absorption or action of drugs administered by the oral, pulmonary, vaginal, nasal or other routes. Solubility and lipophilicity are key factors determining drug absorption, as a drug has to be soluble in the body fluids at the site of absorption and must also possess enough lipophilicity to permeate the biological membrane. Evidence has accumulated over the past 40 years indicating that poorly soluble drugs will interact with mucus glycoprotein. Studies of the permeability of native or purified mucous gels are important when it comes to understanding the relative importance of hindered diffusion versus drug binding in mucous layers. This review highlights the current understanding of the drug-mucin interaction and also examines briefly the interaction of polymers and particles with the mucus matrix. While the concept of mucoadhesion was thought to provide an intensified and prolonged contact to mucosal absorption sites, mucopenetrating properties are nowadays being discussed for (nano)particulate carriers to overcome the mucus as a barrier and enhance drug delivery through mucus. Copyright © 2013 Elsevier B.V. All rights reserved.

  9. The blood-epididymis barrier and inflammation (United States)

    Gregory, Mary; Cyr, Daniel G


    The blood-epididymis barrier (BEB) is a critical structure for male fertility. It enables the development of a specific luminal environment that allows spermatozoa to acquire both the ability to swim and fertilize an ovum. The presence of tight junctions and specific cellular transporters can regulate the composition of the epididymal lumen to favor proper sperm maturation. The BEB is also at the interface between the immune system and sperm. Not only does the BEB protect maturing spermatozoa from the immune system, it is also influenced by cytokines released during inflammation, which can result in the loss of barrier function. Such a loss is associated with an immune response, decreased sperm functions, and appears to be a contributing factor to post-testicular male infertility. Alterations in the BEB may be responsible for the formation of inflammatory conditions such as sperm granulomas. The present review summarizes current knowledge on the morphological, physiological and pathological components associated with the BEB, the role of immune function on the regulation of the BEB, and how disturbance of these factors can result in inflammatory lesions of the epididymis. PMID:26413391

  10. Brain Extracellular Space as a Diffusion Barrier. (United States)

    Nicholson, Charles; Kamali-Zare, Padideh; Tao, Lian


    The extracellular space (ECS) consists of the narrow channels between brain cells together with their geometrical configuration and contents. Despite being only 20-60 nm in width, the ECS typically occupies 20% of the brain volume. Numerous experiments over the last 50 years have established that molecules moving through the ECS obey the laws of diffusion but with an effective diffusion coefficient reduced by a factor of about 2.6 compared to free diffusion. This review considers the origins of the diffusion barrier arising from the ECS and its properties. The paper presents a brief overview of software for implementing two point-source paradigms for measurements of localized diffusion properties: the real-time iontophoresis or pressure method for small ions and the integrative optical imaging method for macromolecules. Selected results are presented. This is followed by a discussion of the application of the MCell Monte Carlo simulation program to determining the importance of geometrical constraints, especially dead-space microdomains, and the possible role of interaction with the extracellular matrix. It is concluded that we can predict the impediment to diffusion of many molecules of practical importance and also use studies of the diffusion of selected molecular probes to reveal the barrier properties of the ECS.

  11. Building a Bridge of Understanding: How Barriers to Training Participation Become Barriers to Training Transfer (United States)

    Brown, T. C.; McCracken, Martin


    Purpose: The purpose of this paper is to look at the issues concerning barriers that managers face in relation to participation in training and transfer of training, which have become increasingly important to HRD scholars and practitioners. To date, these areas have largely been examined independently. This paper aims to argue that there is an…

  12. HRE-Pond Cryogenic Barrier Technology Demonstration: Pre- and Post-Barrier Hydrologic Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Moline, G.R.


    The Homogeneous Reactor Experiment (HRE) Pond is the site of a former impoundment for radioactive wastes on the Oak Ridge Reservation (ORR) in east Tennessee. The pond received radioactive wastes from 1957 to 1962, and was subsequently drained, filled with soil, and covered with an asphalt cap. The site is bordered to the east and south by an unnamed stream that contains significant concentrations of radioactive contaminants, primarily {sup 90}Sr. Because of the proximity of the stream to the HRE disposal site and the probable flow of groundwater from the site to the stream, it was hypothesized that the HRE Pond has been a source of contamination to the creek. The HRE-Pond was chosen as the site of a cryogenic barrier demonstration to evaluate this technology as a means for rapid, temporary isolation of contaminants in the type of subsurface environment that exists on the ORR. The cryogenic barrier is created by the circulation of liquid CO{sub 2} through a system of thermoprobes installed in boreholes which are backfilled with sand. The probes cool the subsurface, creating a vertical ice wall by freezing adjacent groundwater, effectively surrounding the pond on four sides. The purpose of this investigation was to evaluate the hydrologic conditions within and around the pond prior to, during, and after the cryogenic barrier emplacement. The objectives were (1) to provide a hydrologic baseline for post-banner performance assessment, (2) to confirm that the pond is hydraulically connected to the surrounding sediments, (3) to determine the likely contaminant exit pathways from the pond, and (4) to measure changes in hydrologic conditions after barrier emplacement in order to assess the barrier performance. Because relatively little information about the subsurface hydrology and the actual configuration of the pond existed, data from multiple sources was required to reconstruct this complex system.

  13. Vision-based calibration of parallax barrier displays (United States)

    Ranieri, Nicola; Gross, Markus


    Static and dynamic parallax barrier displays became very popular over the past years. Especially for single viewer applications like tablets, phones and other hand-held devices, parallax barriers provide a convenient solution to render stereoscopic content. In our work we present a computer vision based calibration approach to relate image layer and barrier layer of parallax barrier displays with unknown display geometry for static or dynamic viewer positions using homographies. We provide the math and methods to compose the required homographies on the fly and present a way to compute the barrier without the need of any iteration. Our GPU implementation is stable and general and can be used to reduce latency and increase refresh rate of existing and upcoming barrier methods.

  14. Urban sound energy reduction by means of sound barriers

    Directory of Open Access Journals (Sweden)

    Iordache Vlad


    Full Text Available In urban environment, various heating ventilation and air conditioning appliances designed to maintain indoor comfort become urban acoustic pollution vectors due to the sound energy produced by these equipment. The acoustic barriers are the recommended method for the sound energy reduction in urban environment. The current sizing method of these acoustic barriers is too difficult and it is not practical for any 3D location of the noisy equipment and reception point. In this study we will develop based on the same method a new simplified tool for acoustic barriers sizing, maintaining the same precision characteristic to the classical method. Abacuses for acoustic barriers sizing are built that can be used for different 3D locations of the source and the reception points, for several frequencies and several acoustic barrier heights. The study case presented in the article represents a confirmation for the rapidity and ease of use of these abacuses in the design of the acoustic barriers.

  15. Herbal medicines that benefit epidermal permeability barrier function

    Directory of Open Access Journals (Sweden)

    Lizhi Hu


    Full Text Available Epidermal permeability barrier function plays a critical role in regulating cutaneous functions. Hence, researchers have been searching for effective and affordable regimens to enhance epidermal permeability barrier function. In addition to topical stratum corneum lipids, peroxisome proliferator-activated receptor, and liver X receptor ligands, herbal medicines have been proven to benefit epidermal permeability barrier function in both normal and diseased skin, including atopic dermatitis, glucocorticoid-induced skin damage, and UVB-damaged skin. The potential mechanisms by which herbal medicines improve the permeability barrier include stimulation of epidermal differentiation, lipid production, antimicrobial peptide expression, and antioxidation. Therefore, utilization of herbal medicines could be a valuable alternative approach to enhance epidermal permeability barrier function in order to prevent and/or treat skin disorders associated with permeability barrier abnormalities.

  16. Barriers to participation in vocational orientation programmes among prisoners

    Directory of Open Access Journals (Sweden)

    Dorien Brosens


    Full Text Available This study investigates the barriers to prisoners’ participation in vocational education, as well as the predictors of different types of barriers. Survey data derived from a project in a remand prison in Belgium (N=468 provided the empirical evidence for the analyses. The results indicate that facing situational and informational barriers are most common. Based on the different kinds of barriers, various types of non-participants can be distinguished and multinomial logistic regression analyses are conducted to identify in what way participants of vocational education differ from various types of non-participants. For instance, prisoners with a poor understanding of the Dutch language and those who never/rarely receive visitors participate less in vocational education as they are more likely to be confronted with informational barriers. We conclude this article by discussing paths for future research and implications for policy and practice to anticipate the barriers for those who want to participate in vocational education.

  17. Properties of native ultrathin aluminium oxide tunnel barriers

    CERN Document Server

    Gloos, K; Pekola, J P


    We have investigated planar metal-insulator-metal tunnel junctions with aluminium oxide as the dielectricum. These oxide barriers were grown on an aluminium electrode in pure oxygen at room temperature till saturation. By applying the Simmons model we derived discrete widths of the tunnelling barrier, separated by DELTA s approx 0.38 nm. This corresponds to the addition of single layers of oxygen atoms. The minimum thickness of s sub 0 approx 0.54 nm is then due to a double layer of oxygen. We found a strong and systematic dependence of the barrier height on the barrier thickness. Breakdown fields up to 5 GV m sup - sup 1 were reached. They decreased strongly with increasing barrier thickness. Electrical breakdown could be described by a metal-insulator like transition of the dielectric barrier due to the large density of tunnelling electrons.

  18. Dark soliton scattering in symmetric and asymmetric double potential barriers (United States)

    Tsitoura, F.; Anastassi, Z. A.; Marzuola, J. L.; Kevrekidis, P. G.; Frantzeskakis, D. J.


    Motivated by the recent theoretical study of (bright) soliton diode effects in systems with multiple scatterers, as well as by experimental investigations of soliton-impurity interactions, we consider some prototypical case examples of interactions of dark solitons with a pair of scatterers. In a way fundamentally opposite to the case of bright solitons (but consonant to their ;anti-particle character;), we find that dark solitons accelerate as they pass the first barrier and hence cannot be trapped by a second equal-height barrier. A pair of unequal barriers may lead to reflection from the second one, however trapping in the inter-barrier region cannot occur. We also give some examples of dynamical adjusting of the barriers to trap the dark soliton in the inter-barrier region, yet we show that this can only occur over finite time horizons, with the dark soliton always escaping eventually, contrary again to what is potentially the case with bright solitons.

  19. Barriers to implementation of the FUSE program. (United States)

    Nguyen, Brian M; Fitzpatrick, Emilie; Jones, Daniel B


    The Society of American Gastrointestinal and Endoscopic Surgeons (SAGES) developed The Fundamental Use of Surgical Energy (FUSE) Program to promote safe use of energy devices in the operating room and endoscopy suite. Utilization of the program has been slower than anticipated. This study aims to determine the barriers to implementing FUSE. An anonymous survey was distributed to a surgery department at an academic teaching hospital (n = 256). Participants indicated their level of training. Answers were measured using a 5-point Likert scale. There were 94 (36.7%) respondents to the survey from September 7 to 20, 2016. Fifteen surveys were incomplete, leaving 79 responses for analysis. Most respondents were at the faculty level (45/79, 57.0%). The majority had heard of FUSE (62/79, 78.5%), but only 19 had completed the certification (19/62, 32.3%). There was no difference in the completion rate between faculty and trainees (26.7 vs. 20.6%, OR 1.4, 95% CI 0.49-4.06, p = 0.53). The most common reasons for not taking the exam were lack of time to study (26/43, 60.5%) and lack of time to take the exam (28/43, 62.1%); however, cost was not a barrier (12/43, 27.9%). The majority identified a personal learning gap regarding the safe use of surgical energy (30/43, 69.7%). Of the 19 FUSE-certified respondents, reasons cited for completing the exam included wanting to prevent adverse events to patients and in the operating room (17/19, 89.5% and 17/19, 89.5%), and the belief that the course would make them a safer surgeon (16/19, 84.2%). FUSE teaches the proper use of radiofrequency energy, how to prevent unnecessary injury, and promotes safe practice. Close to three out of every four surgeons self-identified a personal knowledge gap regarding the safe use of surgical energy. Time restraints were cited most commonly as the barrier to starting and completing FUSE. Integrating the FUSE program into resident educational conferences, faculty grand rounds, or national


    Energy Technology Data Exchange (ETDEWEB)

    R. Jarek


    The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs

  1. Test device for measuring permeability of a barrier material (United States)

    Reese, Matthew; Dameron, Arrelaine; Kempe, Michael


    A test device for measuring permeability of a barrier material. An exemplary device comprises a test card having a thin-film conductor-pattern formed thereon and an edge seal which seals the test card to the barrier material. Another exemplary embodiment is an electrical calcium test device comprising: a test card an impermeable spacer, an edge seal which seals the test card to the spacer and an edge seal which seals the spacer to the barrier material.

  2. Characterization of components and materials for EMC barriers


    Lundgren, Urban


    This thesis presents contributions to work for better methodologies for addressing Electromagnetic Compatibility (EMC) issues. In particular measurement methods are reviewed and devised for acquiring data on barriers used for EMC. Such data is used for characterization, modeling and model verification of barriers. The concept of EMC barriers is introduced as a general view of filter components, separation of conductors (crosstalk problems), electromagnetic shielding etc. The aim is to find me...

  3. Adherence barriers in pediatric epilepsy: From toddlers to young adults. (United States)

    Gutierrez-Colina, Ana M; Smith, Aimee W; Mara, Constance A; Modi, Avani C


    The objectives of this study were to examine the continuity of adherence barriers across stages of development in pediatric epilepsy and to assess the differential influence of barriers on several important clinical outcomes from early childhood to young adulthood, including adherence, seizures, and health-related quality of life (HRQOL). A developmentally representative sample of youth 2-25years with epilepsy was obtained by combining data from five different studies. A total of 269 caregivers and 77 adolescents and young adults were included in this investigation. Participants completed measures of adherence barriers and HRQOL. An electronic monitoring system was used to assess adherence to the primary antiepileptic drug over 30days. The prevalence of individual barriers across development and their relative importance as predictors of clinical outcomes were examined. Adherence barriers are characterized by both continuity and discontinuity from early childhood to early adulthood. Barriers such as disliking the taste of medication, parent forgetfulness, and refusal to take medications were significantly more salient during certain developmental periods. No significant differences across age groups were found for other barriers, including difficulty getting to the pharmacy and embarrassment. Certain adherence barriers, such as running out of medications, were more important to particular clinical outcomes despite being low prevalence. Adherence barriers differentially predicted adherence, seizure control, and HRQOL based on developmental stage. Routine assessment of adherence barriers is imperative from toddlerhood to young adulthood given that the prevalence of barriers and their relative influence on important health outcomes vary by developmental stage. Adherence intervention efforts should be targeted, developmentally tailored, and focused on those barriers that are most predictive of poor outcomes for a given developmental period. Copyright © 2018 Elsevier

  4. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hampikian, J.M.; Carter, W.B. [Georgia Institute of Technology, Atlanta, GA (United States)


    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  5. Formal Saving in Developing Economies: Barriers, Interventions, and Effects


    Sonia Di Giannatale; María José Roa


    This paper discusses the determinants of and the barriers to formal saving both from the theoretical point of view and based on empirical evidence from various associated interventions and their possible effects at the micro and macroeconomic levels. It presents a comprehensive review of the literature based on a detailed classification of the barriers associated with supply-side factors related to access to financial products and demand-side barriers, related to the use, and frequency of use...

  6. Mobility Barriers and the Speed of Market Selection


    Hölzl, Werner


    This paper studies the influence of mobility barriers on industry evolution using the stylised pure selection model developed by Metcalfe. It is shown that mobility barriers influence industry dynamics by reducing the speed of competitive selection. Based on the theoretical model, we argue that mobility barriers should lead to a reduction of market share reallocation dynamics in models that use replicator dynamics. We then test this prediction empirically, finding that industries with high mo...

  7. "Targeted disruption of the epithelial-barrier by Helicobacter pylori"

    Directory of Open Access Journals (Sweden)

    Wroblewski Lydia E


    Full Text Available Abstract Helicobacter pylori colonizes the human gastric epithelium and induces chronic gastritis, which can lead to gastric cancer. Through cell-cell contacts the gastric epithelium forms a barrier to protect underlying tissue from pathogenic bacteria; however, H. pylori have evolved numerous strategies to perturb the integrity of the gastric barrier. In this review, we summarize recent research into the mechanisms through which H. pylori disrupts intercellular junctions and disrupts the gastric epithelial barrier.

  8. Thermal Barrier For Vented O-Ring Seal (United States)

    Schick, H.; Shadlesky, Philip S.; Perry, Mark C.; Ketner, Donald M.; Salita, Mark


    Barrier allows gases to seat seal without damaging it. Ring of tungsten-wire mesh forms protective barrier between hot, pressurized combustion gases and O-rings. Mesh cools and depressurizes gases so they safely push on and thereby help to seat primary O-ring or secondary O-ring if primary O-ring fails to form seals. Barrier devised for use in rocket motor. Potential terrestrial applications includes aircraft engines, furnaces, and ducts carrying hot gases.

  9. Streptozotocin-induced diabetes, and the optic nerve blood barrier. (United States)

    Alemán, R; Mompeó, B; Castaño, I


    To study the features of the endoneurial micro-vessels of the optic nerve in streptozotocin-induced diabetic animals. Optic nerves from control and streptozotocin-induced diabetic animals were studied by light and transmission electron microscopy. Patency was determined by indirect immunofluorescence albumin detection. The expression of major histocompatibility complex class II molecules was performed by direct immunofluorescence. The endoneurial vessels were counted, and the endothelial cell, the basement membrane, and the surface of the transverse section of the nerve were measured. Vessels of diabetic rats showed vessel wall thickening, preservation of pericytes, an increase in endothelial cell transcytosis, and an increased number of perivascular macrophage cells. It may be concluded that the effects of hyperglycaemia on the inner vessels of the optic nerve are more similar to the cerebral diabetic vessels than to the retinal vessels in diabetic animals. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  10. Overcoming Barriers to Electric-Vehicle Deployment: Interim Report

    National Research Council Canada - National Science Library


    .... There are, however, substantial technical, social, and economic barriers to widespread adoption of electric vehicles, including vehicle cost, small driving range, long charging times, and the need...

  11. Linguistic and Cultural Barriers to Intercultural Communication in Foreign Subsidiaries

    DEFF Research Database (Denmark)

    Peltokorpi, Vesa; Clausen, Lisbeth


    This study examines the causes and consequences of linguistic and cultural barriers to inter-cultural communication in Nordic subsidiaries in Japan. Interviews with 30 Nordic (Finland, Denmark, Norway and Sweden) expatriates and 29 Japanese employees show that the main linguistic barriers...... to intercultural communication were lack of a shared language and low motivation to improve foreign-language proficiency. The main cultural barriers were collectivism, and status and power differences. Combined, the consequences of these barriers were extensive reliance on language intermediaries, information...

  12. Hydrologic behavior of two engineered barriers following extreme wetting. (United States)

    Porro, I


    Many engineered barriers are expected to function for hundreds of years or longer. Over the course of time, it is likely that some barriers will experience infiltration to the point of breakthrough. This study compares the recovery from breakthrough of two storage-evapotranspiration type engineered barriers. Replicates of test plots comprising thick soil and capillary-biobarrier covers were wetted to breakthrough in 1997. Test plots were kept cleared of vegetation to maximize hydrologic stress during recovery. Following cessation of drainage resulting from the wetting irrigations, water storage levels in all plots were at elevated levels compared with pre-irrigation levels. As a result, infiltration of melting snow during the subsequent spring overloaded the storage capacity and produced drainage in all plots. Relatively rapid melting of accumulated snowfall produced the most significant infiltration events each year during the study. Capillary barriers yielded less total drainage than thick soil barriers. By limiting drainage, capillary barriers increased water storage in the upper portions of the test plots, which led to increased evaporation from the capillary barrier plots compared with thick soil plots. Increased evaporation in the capillary barrier plots allowed more water to infiltrate in the second season following the wetting tests without triggering drainage. All thick soil plots again yielded drainage in the second season. Within two years of intentionally induced breakthrough, evaporation alone (without transpiration) restored the capability of the capillary barrier covers to function as intended, although water storage in these covers remained at elevated levels.

  13. Combination Thermal Barrier And Wear Coatings For Engines (United States)

    Weingart, Mike; Moller, Paul


    Thermal-barrier layers covered with self-lubricating surface layers. Zirconia thermal-barrier coat applied to surface of combustion chamber in engine by plasma-arc spraying. Then PS-200 plasma-arc sprayed onto zirconia. Self-lubricating coat prevents sliding contact between thermal barrier and piston ring, effectively preventing both wear and production of additional heat via friction. Other combinations of thermal-barrier and self-lubricating, wear-resistant coating materials used as long as two materials adhere to each other, applied by use of similar or compatible processes, have similar coefficients of thermal expansion, sufficiently strong at high temperatures, and affordable.

  14. Perceived barriers to physical activity in university students. (United States)

    Arzu, Daskapan; Tuzun, Emine Handan; Eker, Levent


    Many studies which were published in other countries identified certain benefits and barriers to physical activity among young people. But there is no data about the subject pertaining to Turkish adolescents. This study tries to rectify this with a study of Turkish university students. Undergraduate university students (n = 303) were recruited to the study. Current exercise habits and perceived barriers to physical activity were assessed in the sample. Using a Likert Type scale, participants responded an instrument with 12 items representing barriers to physical activity. Mean scores were computed. External barriers were more important than internal barriers. "Lack of time due to busy lesson schedule", "My parents give academic success priority over exercise. "and "lack of time due to responsibilities related to the family and social environment "were most cited items for physical activity barriers. There is a need for future research, which will be carried out with larger sample groups to develop national standardized instrument. It will be helpful for accurately identify perceived barriers and then recommend changes to enhance physical activity among young people. Key PointsThe purpose of this study was to analyze perceived barriers to physical activity in the university students.The results showed that not having enough time was the most important barrier for not participating in physical activity among our samples.This study with relatively small sample must be considered as pilot study for related studies in the future.

  15. Barriers to Investment in Energy from Renewable Sources

    Directory of Open Access Journals (Sweden)

    Corina PÎRLOGEA


    Full Text Available This paper attempts to create an overview of the current situation in the Romanian energy sector, pointing out elements of energy demand, production, investment in the sector and not least the potential of renewable energy sources. As Romania has aligned itself with the European Commission's 20-20-20 program, an important step in achieving the set targets is represented by a significant amount of investments in the development of energy from renewable sources. But there are a number of challenges that investment projects may face, namely, barriers more or less deliberate, more difficult or easier to overcome or remove, some of them real market distortions and others coming from the comparison between green energy and classic sources of energy. So, the last part of the work is dedicated to these barriers. Dividing them into four categories administrative barriers, technical and technological barriers, market barriers and economic barriers allows a better distribution of the identified barriers. It is a comprehensive and equitable approach than their splitting into cost barriers and non-cost barriers, which would have meant a long list for the second category specified.


    Directory of Open Access Journals (Sweden)

    Henry Mwanaki Alinaitwe


    Full Text Available Engaging in lean construction efforts could prove to be highly rewarding for building firms in Uganda. However, lean construction is risky and can be disastrous if not properly managed. Lean production efforts in some other countries have not been successful due to the many barriers to its successful implementation. To enable sound lean construction efforts and to increase the chances of success in eliminating waste, a thorough investigation of the barriers is essential. This study presents 31 barriers and investigates their influence (strength on the success of lean construction initiatives. Structured interviews were carried out with technical managers of building firms to assess their perception of the barriers to lean production based on their experience at their firms. The strongest barrier is the provision of inputs exactly when required. Additionally, the barriers were ranked according to the ease of overcoming each. The easiest barrier to overcome is keeping the required items in the right place. Finally, a graphical aid is provided to enable decision makers to concentrate their efforts on the influential (strong, yet easy to overcome barriers. A lack of buildable designs and a participative management style for the workforce are the most important barriers to successful waste reduction in terms of strength and ease of overcoming. On the other hand, a lack of an organisational culture that supports teamwork, a lack of prefabrication and a lack of knowledgeable and skilled workers are regarded as low in strength, and at the same time difficult to overcome.

  17. Mechanisms and genetic control of interspecific crossing barriers in Lycopersicon

    Energy Technology Data Exchange (ETDEWEB)

    Mutschler, M.A. (Cornell Univ., Ithaca, NY (United States)); McCormick, S. (Agricultural Research Service, Albany, CA (United States). Plant Gene Expression Center)


    This study employs Lycopersicon esculentum and L. pennellii as model systems to study the interspecific reproductive barriers unilateral incongruity (UI), hybrid breakdown and interspecific aberrant ratio syndrome (IARS).

  18. Experienced Barriers to Lean in Swedish Manufacturing and Health Care

    Directory of Open Access Journals (Sweden)

    Bengt Halling


    Full Text Available The purpose is to compare similarities and divergences in how the concepts of Lean and barriers to Lean are described by key informants at a production unit in a large manufacturing company and two emergency health care units in Sweden. Data was collected via semi-structured interviews and analyzed with the constant comparative method (CCM and Porras and Robertson’s (1992 change model. : In both organizations, the view of Lean changed from a toolbox to a human behavior view. Eight barriers were experienced in both organizations. Three barriers were unique to manufacturing or to health care, respectively. Nine barriers were elements of social factors; five were elements of organizing arrangements. Only people practically involved and responsible for the implementation at the two organizations participated in the study. Persons responsible for implementing Lean should consider organizational arrangements and social factors in order to limit barriers to successful implementation. Most research on Lean has been about successful Lean implementations. This study focuses on how Lean is viewed and what barriers personnel in manufacturing and health care have experienced. In comparing the barriers to Lean experienced in the two groups, common, archetypical, and unique barriers for manufacturing and health care can be identified, thus contributing to knowledge about barriers to Lean implementation.

  19. Drivers and barriers of public innovation in crime prevention

    National Research Council Canada - National Science Library

    Peter Aagaard


      Public managers experience a growing demand for innovation. According to the public innovation literature, the barriers and drivers of public innovation are path dependently shaped by institutions...

  20. High-resolution reconstruction of a coastal barrier system

    DEFF Research Database (Denmark)

    Fruergaard, Mikkel; Andersen, Thorbjørn Joest; Nielsen, Lars Henrik


    This study presents a detailed reconstruction of the sedimentary effects of Holocene sea-level rise on a modern coastal barrier system (CBS). Increasing concern over the evolution of CBSs due to future accelerated rates of sea-level rise calls for a better understanding of coastal barriers response...... from retreat of the barrier island and probably also due to formation of a tidal inlet close to the study area. Continued transgression and shoreface retreat created a distinct hiatus and wave ravinement surface in the seaward part of the CBS before the barrier shoreline stabilised between 5.0 and 4...

  1. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.


    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  2. Thermal barrier coatings for gas turbine and diesel engines (United States)

    Miller, Robert A.; Brindley, William J.; Bailey, M. Murray


    The present state of development of thin thermal barrier coatings for aircraft gas turbine engines and thick thermal barrier coatings for truck diesel engines is assessed. Although current thermal barrier coatings are flying in certain gas turbine engines, additional advances will be needed for future engines. Thick thermal barrier coatings for truck diesel engines have advanced to the point where they are being seriously considered for the next generation of engine. Since coatings for truck engines is a young field of inquiry, continued research and development efforts will be required to help bring this technology to commercialization.

  3. Overcoming learning barriers through knowledge management. (United States)

    Dror, Itiel E; Makany, Tamas; Kemp, Jonathan


    The ability to learn highly depends on how knowledge is managed. Specifically, different techniques for note-taking utilize different cognitive processes and strategies. In this paper, we compared dyslexic and control participants when using linear and non-linear note-taking. All our participants were professionals working in the banking and financial sector. We examined comprehension, accuracy, mental imagery & complexity, metacognition, and memory. We found that participants with dyslexia, when using a non-linear note-taking technique outperformed the control group using linear note-taking and matched the performance of the control group using non-linear note-taking. These findings emphasize how different knowledge management techniques can avoid some of the barriers to learners. Copyright © 2010 John Wiley & Sons, Ltd.

  4. Stratum Corneum Barrier Lipids in Cholesteatoma

    DEFF Research Database (Denmark)

    Svane-Knudsen, V; Halkier-Sørensen, L; Rasmussen, G


    Specimens from primary cholesteatomas were examined under the electron microscope using a lipid-retaining method that is best suited for intracellular lipids and a method that is best for intercellular lipids. In the stratum granulosum of the squamous epithelium, a large number of Odland bodies...... emerged. When the corneocyte reaches the transitional stage to the stratum corneum, the Odland bodies accumulate near the cell membrane and discharge their contents of lipid and enzymes. The lipids are reorganized into multiple long sheets of lamellar structures that embrace the keratinized corneocytes......, as seen in the formation and maintenance of the cutaneous permeability barrier. In this study we draw the attention to the facts that the cholesteatoma epithelium is capable of producing not only cholesterol, but also several lipids, and that the lipid molecules are organized in multilamellar structures...

  5. Barriers to increased market-oriented activity

    DEFF Research Database (Denmark)

    Bisp, Søren


    and related activities still seem to attract relatively few resources is not answered by supplying another checklist or package of facilitators. Based on published conceptual writings and empirical studies this article makes an account of what the intra-organizational barriers may be to increased market......Most research on market orientation has dealt with assessing how market orientation behaviour is related to business performance. This work has established an intense market-oriented activity as significantly and positively related to business performance under most circumstances. In a maturing......-oriented activity. A framework of six generic domains is suggested: Organizational structure, human resource management, market-oriented activity competence, psychological climate, managers' personality characteristics, and individually held beliefs. A model is suggested inter-relating the domains....

  6. Maximizing competition : reducing barriers for new players

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, H. [Independent Electricity Market Operator, Toronto, ON (Canada); Cramer, D. [Sithe Energies Inc., Toronto, ON (Canada); McLeese, R. [Access Capital Corp., Toronto, ON (Canada); Singer, J. [Ontario Power Generation Inc., Toronto, ON (Canada)


    This session included highlights from four guest speakers who commented on ways to reduce barriers to competition in Ontario's electric power industry. Topics of discussion included intertie transaction failures, the lack of overall investment in the market, the government's inaction which is preventing investment, the continued underwriting of Ontario Power Generation's activities by the government which discourages investment in the private sector, and indecisiveness regarding policy on coal plants. It was emphasized that investors need to know for certain that they can get a reasonable rate of return on their investments, that the market will be transparent and there will be no shift in policy. The need to promote new, efficient power generation by means of nuclear, coal, natural gas, and hydro energy was also emphasized. Charts depicting total energy production by source were presented for 2001 with projections to 2012. figs.

  7. Overcoming barriers to student participation in research

    Directory of Open Access Journals (Sweden)

    Tanna R


    Full Text Available Ravina Tanna,1,* Nikhil Patel,1,* Sameera Tanna21Imperial College School of Medicine, Imperial College London, South Kensington, 2King's College London Medical School, King's College London, London Bridge, London, UK  *These authors contributed equally to this workWe read with great interest Sheikh et al’s study1 on factors contributing to lack of interest in research among medical students in Pakistan. As students in London, UK, we agree that there are a number of barriers preventing medical students engaging in research activities, such as underestimating the importance of research and difficulties making contacts with academics in order to undertake a project.View original article by Sheikh et al

  8. Transfer reactions below the Coulomb barrier

    Energy Technology Data Exchange (ETDEWEB)

    Napoli, D.R.; Stefanini, A.M.; Million, B.; Narayanasamy, M.; Prete, G.; Spolaore, P.; Li Zichang (INFN, Legnaro (Italy) Lab. Nazionali, Legnaro (Italy)); Moreno Gonzalez, H. (INFN, Legnaro (Italy) Lab. Nazionali, Legnaro (Italy) Dept. de Fisica Atomica y Nuclear, Univ. Sevilla (Spain)); Pollarolo, G. (Univ. Turin (Italy) INFN, Turin (Italy)); Beghini, S.; Montagnoli, G.; Scarlassara, F.; Segato, G.F.; Signorini, C.; Soramel, F. (Univ. Padua (Italy) INFN, Padua (Italy)); Rapisarda, A. (INFN, Catania (Italy))


    We report here on the measurements of one-particle transfer cross sections and quasi-elastic scattering of [sup 32]Si+[sup 64]Ni at energies around and well below the Coulomb barrier. The experiment has been performed with the Legnaro Recoil Mass Spectrometer. We have measured the excitation function at [theta][sub cm]=170deg from E[sub lab]=68.3 to 92.4 MeV and the angular distribution at E[sub lab]=81.3 MeV from [theta][sub cm]=120deg to 170deg. The results have been analysed in the framework of the complex WKB theory and the semiclassical approach based on Coulomb trajectories. (orig.).

  9. Barriers of the Human Capital Shaping

    Directory of Open Access Journals (Sweden)

    Joanna Krochmal


    Full Text Available Nowadays, in the age of the economy focused on knowledge and science, the process of formation and development of the employees is considered as a very important investment, inspiration and a tool to efficiency creating, success and first of all, the strategic potential of the company. Indeed, it is people who are the key and the path to success and on them, the strength, the power and the success of any business should be built. The aim of this elaboration is to highlight and emphasize the importance of investment in human capital and show fluctuations, as one of the barriers that can disrupt this development, what in general also may be caused by lack of adequate systems of employees motivation.

  10. Thermal barrier coatings for heat engine components (United States)

    Levine, S. R.; Miller, R. A.; Hodge, P. E.


    A comprehensive NASA-Lewis program of coating development for aircraft gas turbine blades and vanes is presented. Improved ceramic layer compositions are investigated, along the MCrAlY bond films and the methods of uniform deposition of the coatings; the thermomechanical and fuel impurity tolerance limits of the coatings are being studied. Materials include the ZrO2-Y2O3/NiCrAlY system; the effects of the bond coat and zirconia composition on coating life and Mach 1 burner rig test results are discussed. It is concluded that Diesel engines can also utilize thermal barrier coatings; they have been used successfully on piston crowns and exhaust valves of shipboard engines to combat lower grade fuel combustion corrosion.

  11. Quantum mechanical streamlines. I - Square potential barrier (United States)

    Hirschfelder, J. O.; Christoph, A. C.; Palke, W. E.


    Exact numerical calculations are made for scattering of quantum mechanical particles hitting a square two-dimensional potential barrier (an exact analog of the Goos-Haenchen optical experiments). Quantum mechanical streamlines are plotted and found to be smooth and continuous, to have continuous first derivatives even through the classical forbidden region, and to form quantized vortices around each of the nodal points. A comparison is made between the present numerical calculations and the stationary wave approximation, and good agreement is found between both the Goos-Haenchen shifts and the reflection coefficients. The time-independent Schroedinger equation for real wavefunctions is reduced to solving a nonlinear first-order partial differential equation, leading to a generalization of the Prager-Hirschfelder perturbation scheme. Implications of the hydrodynamical formulation of quantum mechanics are discussed, and cases are cited where quantum and classical mechanical motions are identical.

  12. Evidence over barriers: important but not enough. (United States)

    Sinclair, Duncan G


    Overcoming the boundary conditions that impede the flow of evidence derived from research from academia to healthcare decision-makers in government and their agencies continues to be a challenge. But even the reduction/elimination of all such barriers and perfect collaboration are unlikely to yield what those of us in the "real world" yearn for, doing the right things right - policy and other decisions perfectly informed by evidence of what works and what doesn't to achieve a defined outcome. For that to happen, the calculus of decision-makers would have to exclude or evidence would have to trump political considerations, both large P and small p, an unlikely accomplishment in British Columbia or anywhere in our so-called healthcare system. That's reality!

  13. Conversations through barriers of language and interpretation. (United States)

    McCarthy, Jane; Cassidy, Irene; Graham, Margaret M; Tuohy, Dympna

    Ireland has become a multicultural society in just over a decade, with non-Irish nationals comprising 12% of the population. The challenge for nurses working in the Irish healthcare system is to provide culturally appropriate care to this diverse population. This paper reports on a qualitative descriptive study exploring nurses' experiences of communicating with people from diverse cultures, and focuses on language barriers and the use of interpreters. The findings indicate that communicating with people who do not share the same first language is challenging, in particular the participants (nurses) were concerned about their ability to make a comprehensive assessment that ultimately forms the basis for quality care provision. The use of interpreters can inform the assessment process, but there are challenges in accessing and utilising these services. Further continuing education is required to promote culturally appropriate care. There is a need for increased discussion between nurses and interpreters to maximise communication with patients.

  14. Barriers to emergency obstetric care services

    DEFF Research Database (Denmark)

    Echoka, Elizabeth; Makokha, Anselimo; Dubourg, Dominique


    decision to seek care and in reaching an appropriate care facility. The "first" delay was due to lack of birth preparedness, including failure to identify a health facility for delivery services regardless of antenatal care and to seek care promptly despite recognition of danger signs. The "second" delay...... barriers to emergency obstetric care (EmOC) services by women who experienced life threatening obstetric complications in Malindi District, Kenya. Methods: A facility-based qualitative study was conducted between November and December 2010. In-depth interviews were conducted with 30 women who experienced...... obstetric "near miss" at the only public hospital with capacity to provide comprehensive EmOC services in the district. Elizabeth Echoka1,&, Anselimo Makokha2, Dominique Dubourg3, Yeri Kombe1, Lillian Nyandieka1, Jens Byskov4 Results: Findings indicate that pregnant women experienced delays in making...

  15. Barriers to Access to Palliative Care (United States)

    Hawley, Pippa


    Despite significant advances in understanding the benefits of early integration of palliative care with disease management, many people living with a chronic life-threatening illness either do not receive any palliative care service or receive services only in the last phase of their illness. In this article, I explore some of the reasons for failure to provide palliative care services and recommend some strategies to overcome these barriers, emphasizing the importance of describing palliative care accurately. I provide language which I hope will help health care professionals of all disciplines explain what palliative care has to offer and ensure wider access to palliative care, early in the course of their illness. PMID:28469439

  16. Proton emission with a screened electrostatic barrier

    Energy Technology Data Exchange (ETDEWEB)

    Budaca, R. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania); Academy of Romanian Scientists, Bucharest (Romania); Budaca, A.I. [Horia Hulubei National Institute of Physics and Nuclear Engineering, Bucharest-Magurele (Romania)


    Half-lives of proton emission for Z ≥ 51 nuclei are calculated within a simple analytical model based on the WKB approximation for the barrier penetration probability which includes the centrifugal and overlapping effects besides the electrostatic repulsion. The model has a single free parameter associated to a Hulthen potential which emulates a Coulomb electrostatic interaction only at short distance. The agreement with experimental data is very good for most of the considered nuclei. Theoretical predictions are made for few cases with uncertain emitting state configuration or incomplete decay information. The model's assignment of the proton orbital momentum is in agreement with the differentiation of the experimental data by orbital momentum values realized with a newly introduced correlation formula. (orig.)

  17. Medulloblastoma Genotype Dictates Blood Brain Barrier Phenotype. (United States)

    Phoenix, Timothy N; Patmore, Deanna M; Boop, Scott; Boulos, Nidal; Jacus, Megan O; Patel, Yogesh T; Roussel, Martine F; Finkelstein, David; Goumnerova, Liliana; Perreault, Sebastien; Wadhwa, Elizabeth; Cho, Yoon-Jae; Stewart, Clinton F; Gilbertson, Richard J


    The childhood brain tumor, medulloblastoma, includes four subtypes with very different prognoses. Here, we show that paracrine signals driven by mutant β-catenin in WNT-medulloblastoma, an essentially curable form of the disease, induce an aberrant fenestrated vasculature that permits the accumulation of high levels of intra-tumoral chemotherapy and a robust therapeutic response. In contrast, SHH-medulloblastoma, a less curable disease subtype, contains an intact blood brain barrier, rendering this tumor impermeable and resistant to chemotherapy. The medulloblastoma-endothelial cell paracrine axis can be manipulated in vivo, altering chemotherapy permeability and clinical response. Thus, medulloblastoma genotype dictates tumor vessel phenotype, explaining in part the disparate prognoses among medulloblastoma subtypes and suggesting an approach to enhance the chemoresponsiveness of other brain tumors. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Electrical insulator assembly with oxygen permeation barrier (United States)

    Van Der Beck, Roland R.; Bond, James A.


    A high-voltage electrical insulator (21) for electrically insulating a thermoelectric module (17) in a spacecraft from a niobium-1% zirconium alloy wall (11) of a heat exchanger (13) filled with liquid lithium (16) while providing good thermal conductivity between the heat exchanger and the thermoelectric module. The insulator (21) has a single crystal alumina layer (SxAl.sub.2 O.sub.3, sapphire) with a niobium foil layer (32) bonded thereto on the surface of the alumina crystal (26) facing the heat exchanger wall (11), and a molybdenum layer (31) bonded to the niobium layer (32) to act as an oxygen permeation barrier to preclude the oxygen depleting effects of the lithium from causing undesirable niobium-aluminum intermetallic layers near the alumina-niobium interface.

  19. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities in Assessing the Degradation of Cementitious Barriers - 13487

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G.P.; Burns, H.H.; Langton, C.; Smith, F.G. III [Savannah River National Laboratory, Savannah River Site, Aiken SC 29808 (United States); Brown, K.G.; Kosson, D.S.; Garrabrants, A.C.; Sarkar, S. [Vanderbilt University, Nashville, TN (United States); Van der Sloot, H. [Hans Van der Sloot Consultancy (Netherlands); Meeussen, J.C.L. [Nuclear Research and Consultancy Group, Petten (Netherlands); Samson, E. [SIMCO Technologies Inc., 1400, boul. du Parc-Technologique, Suite 203, Quebec (Canada); Mallick, P.; Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW, Washington, DC (United States); Esh, D.W.; Fuhrmann, M.J.; Philip, J. [U.S. Nuclear Regulatory Commission, Washington, DC (United States)


    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in K{sub d}/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP

  20. The Cementitious Barriers Partnership (CBP) Software Toolbox Capabilities In Assessing The Degradation Of Cementitious Barriers

    Energy Technology Data Exchange (ETDEWEB)

    Flach, G. P. [Savannah River Site (SRS), Aiken, SC (United States); Burns, H. H. [Savannah River Site (SRS), Aiken, SC (United States); Langton, C. [Savannah River Site (SRS), Aiken, SC (United States); Smith, F. G. III [Savannah River Site (SRS), Aiken, SC (United States); Brown, K. G. [Vanderbilt University, Nashville, TN (United States); Kosson, D. S. [Vanderbilt University, Nashville, TN (United States); Garrabrants, A. C. [Vanderbilt University, Nashville, TN (United States); Sarkar, S. [Vanderbilt University, Nashville, TN (United States); van der Sloot, H. [Hans van der Sloot Consultancy (The Netherlands); Meeussen, J. C.L. [Nuclear Research and Consultancy Group, Petten (The Netherlands); Samson, E. [SIMCO Technologies Inc. , 1400, boul. du Parc - Technologique , Suite 203, Quebec (Canada); Mallick, P. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Suttora, L. [United States Department of Energy, 1000 Independence Ave. SW , Washington, DC (United States); Esh, D. W. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Fuhrmann, M. J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States); Philip, J. [U .S. Nuclear Regulatory Commission , Washington, DC (United States)


    The Cementitious Barriers Partnership (CBP) Project is a multi-disciplinary, multi-institutional collaboration supported by the U.S. Department of Energy (US DOE) Office of Tank Waste and Nuclear Materials Management. The CBP program has developed a set of integrated tools (based on state-of-the-art models and leaching test methods) that help improve understanding and predictions of the long-term structural, hydraulic and chemical performance of cementitious barriers used in nuclear applications. Tools selected for and developed under this program have been used to evaluate and predict the behavior of cementitious barriers used in near-surface engineered waste disposal systems for periods of performance up to 100 years and longer for operating facilities and longer than 1000 years for waste disposal. The CBP Software Toolbox has produced tangible benefits to the DOE Performance Assessment (PA) community. A review of prior DOE PAs has provided a list of potential opportunities for improving cementitious barrier performance predictions through the use of the CBP software tools. These opportunities include: 1) impact of atmospheric exposure to concrete and grout before closure, such as accelerated slag and Tc-99 oxidation, 2) prediction of changes in Kd/mobility as a function of time that result from changing pH and redox conditions, 3) concrete degradation from rebar corrosion due to carbonation, 4) early age cracking from drying and/or thermal shrinkage and 5) degradation due to sulfate attack. The CBP has already had opportunity to provide near-term, tangible support to ongoing DOE-EM PAs such as the Savannah River Saltstone Disposal Facility (SDF) by providing a sulfate attack analysis that predicts the extent and damage that sulfate ingress will have on the concrete vaults over extended time (i.e., > 1000 years). This analysis is one of the many technical opportunities in cementitious barrier performance that can be addressed by the DOE-EM sponsored CBP software