Science.gov

Sample records for hyperphosphorylation detaches 3-repeat

  1. Hyperphosphorylation-induced tau oligomers.

    PubMed

    Iqbal, Khalid; Gong, Cheng-Xin; Liu, Fei

    2013-01-01

    In normal adult brain the microtubule associated protein (MAP) tau contains 2-3 phosphates per mol of the protein and at this level of phosphorylation it is a soluble cytosolic protein. The normal brain tau interacts with tubulin and promotes its assembly into microtubules and stabilizes these fibrils. In Alzheimer disease (AD) brain tau is three to fourfold hyperphosphorylated. The abnormally hyperphosphorylated tau binds to normal tau instead of the tubulin and this binding leads to the formation of tau oligomers. The tau oligomers can be sedimented at 200,000 × g whereas the normal tau under these conditions remains in the supernatant. The abnormally hyperphosphorylated tau is capable of sequestering not only normal tau but also MAP MAP1 and MAP2 and causing disruption of the microtubule network promoted by these proteins. Unlike Aβ and prion protein (PrP) oligomers, tau oligomerization in AD and related tauopathies is hyperphosphorylation-dependent; in vitro dephosphorylation of AD P-tau with protein phosphatase 2A (PP2A) inhibits and rehyperphosphorylation of the PP2A-AD P-tau with more than one combination of tau protein kinases promotes its oligomerization. In physiological assembly conditions the AD P-tau readily self-assembles into paired helical filaments. Missense tau mutations found in frontotemporal dementia apparently lead to tau oligomerization and neurofibrillary pathology by promoting its abnormal hyperphosphorylation. Dysregulation of the alternative splicing of tau that alters the 1:1 ratio of the 3-repeat: 4-repeat taus such as in Down syndrome, Pick disease, and progressive supranuclear palsy leads to the abnormal hyperphosphorylation of tau.

  2. Endogenous Aβ causes cell death via early tau hyperphosphorylation.

    PubMed

    Amadoro, G; Corsetti, V; Ciotti, M T; Florenzano, F; Capsoni, S; Amato, G; Calissano, P

    2011-06-01

    Alzheimer's disease (AD) is characterized by Aβ overproduction and tau hyperphosphorylation. We report that an early, transient and site-specific AD-like tau hyperphosphorylation at Ser262 and Thr231 epitopes is temporally and causally related with an activation of the endogenous amyloidogenic pathway that we previously reported in hippocampal neurons undergoing cell death upon NGF withdrawal [Matrone, C., Ciotti, M.T., Mercanti, D., Marolda, R., Calissano, P., 2008b. NGF and BDNF signaling control amyloidogenic route and Ab production in hippocampal neurons. Proc. Natl. Acad. Sci. 105, 13138-13143]. Such tau hyperphosphorylation, as well as apoptotic death, is (i) blocked by 4G8 and 6E10 Aβ antibodies or by specific β and/or γ-secretases inhibitors; (ii) temporally precedes tau cleavage mediated by a delayed (6-12h after NGF withdrawal) activation of caspase-3 and calpain-I; (iii) under control of Akt-GSK3β-mediated signaling. Finally, we show that such site-specific tau hyperphosphorylation causes tau detachment from microtubules and an impairment of mitochondrial trafficking. These results depict, for the first time, a rapid interplay between endogenous Aβ and tau post-translational modifications which act co-ordinately to compromise neuronal functions in the same neuronal system, under physiological conditions as seen in AD brain. Copyright © 2009 Elsevier Inc. All rights reserved.

  3. Vitreous Detachment

    MedlinePlus

    ... of vision. Treatment How does vitreous detachment affect vision? Although a vitreous detachment does not threaten sight, ... hole or detached retina can lead to permanent vision loss in the affected eye. Those who experience ...

  4. Retinal detachment.

    PubMed

    Cavallerano, A A

    1992-01-01

    Retinal detachment is a separation of the neurosensory retina from the retinal pigment epithelium. Most retinal detachments are rhegmatogenous, and identification of risk factors and predisposing lesions are important aspects of patient management. Retinal detachment is relatively rare, but can pose a significant threat to vision if there is macular involvement. Prompt diagnosis combined with patient education and appropriate intervention often can avert irrevocable visual impairment. This paper presents an overview of the categories of retinal detachment, discusses the pathogenesis of the various types of detachment, and provides recommendations for primary care of patients with predisposing factors and high-risk characteristics.

  5. Divertor detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, Sergei

    2015-11-01

    The heat exhaust is one of the main conceptual issues of magnetic fusion reactor. In a standard operational regime the large heat flux onto divertor target reaches unacceptable level in any foreseeable reactor design. However, about two decades ago so-called ``detached divertor'' regimes were found. They are characterized by reduced power and plasma flux on divertor targets and look as a promising solution for heat exhaust in future reactors. In particular, it is envisioned that ITER will operate in a partly detached divertor regime. However, even though divertor detachment was studied extensively for two decades, still there are some issues requiring a new look. Among them is the compatibility of detached divertor regime with a good core confinement. For example, ELMy H-mode exhibits a very good core confinement, but large ELMs can ``burn through'' detached divertor and release large amounts of energy on the targets. In addition, detached divertor regimes can be subject to thermal instabilities resulting in the MARFE formation, which, potentially, can cause disruption of the discharge. Finally, often inner and outer divertors detach at different plasma conditions, which can lead to core confinement degradation. Here we discuss basic physics of divertor detachment including different mechanisms of power and momentum loss (ionization, impurity and hydrogen radiation loss, ion-neutral collisions, recombination, and their synergistic effects) and evaluate the roles of different plasma processes in the reduction of the plasma flux; detachment stability; and an impact of ELMs on detachment. We also evaluate an impact of different magnetic and divertor geometries on detachment onset, stability, in- out- asymmetry, and tolerance to the ELMs. Supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences under Award Number DE-DE-FG02-04ER54739 at UCSD.

  6. Retinal detachment

    MedlinePlus

    ... of the retina responsible for sharp, detailed vision. Symptoms Symptoms of detached retina can include: Bright flashes of ... right away or within a short time after diagnosis. Some types of surgery can be done in ...

  7. Retinal Detachment

    MedlinePlus

    ... immediately. Treatment How is retinal detachment treated? Small holes and tears are treated with laser surgery or ... laser surgery tiny burns are made around the hole to “weld” the retina back into place. Cryopexy ...

  8. Retinal Detachment

    MedlinePlus

    The retina is a layer of tissue in the back of your eye that senses light and sends images ... for reading, driving, and seeing fine detail. A retinal detachment lifts or pulls the retina from its ...

  9. Retinal detachment

    PubMed Central

    2010-01-01

    Introduction Rhegmatogenous retinal detachment (RRD) is the most common form of retinal detachment, where a retinal "break" allows the ingress of fluid from the vitreous cavity to the subretinal space, resulting in retinal separation. It occurs in about 1 in 10,000 people a year. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent progression from retinal breaks or lattice degeneration to retinal detachment? What are the effects of different surgical interventions in people with rhegmatogenous retinal detachment? What are the effects of interventions to treat proliferative vitreoretinopathy occurring as a complication of retinal detachment or previous treatment for retinal detachment? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2010 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 21 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: corticosteroids, cryotherapy, daunorubicin, fluorouracil plus low molecular weight heparin, laser photocoagulation, pneumatic retinopexy, scleral buckling, short-acting or long-acting gas tamponade, silicone oil tamponade, and vitrectomy. PMID:21406128

  10. Retinal detachment

    PubMed Central

    2009-01-01

    Introduction Rhegmatogenous retinal detachment (RRD) is the most common form of retinal detachment, where a retinal "break" allows the ingress of fluid from the vitreous cavity to the subretinal space, resulting in retinal separation. It occurs in about 1 in 10,000 people a year. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent progression from retinal breaks or lattice degeneration to retinal detachment? What are the effects of different surgical interventions in people with rhegmatogenous retinal detachment? What are the effects of interventions to treat proliferative vitreoretinopathy occurring as a complication of retinal detachment or previous treatment for retinal detachment? We searched: Medline, Embase, The Cochrane Library, and other important databases up to March 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 20 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: corticosteroids; cryotherapy; daunorubicin; fluorouracil plus low-molecular-weight heparin; laser photocoagulation; pneumatic retinopexy; scleral buckling; short-acting or long-acting gas tamponade; silicone oil tamponade; and vitrectomy. PMID:19450333

  11. Retinal detachment

    PubMed Central

    2014-01-01

    Introduction Rhegmatogenous retinal detachment (RRD) is the most common form of retinal detachment, where a retinal 'break' allows the ingress of fluid from the vitreous cavity to the subretinal space, resulting in retinal separation. It occurs in about 1 in 10,000 people a year. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of different surgical interventions in people with rhegmatogenous retinal detachment? What are the effects of interventions to treat proliferative vitreoretinopathy occurring as a complication of retinal detachment or previous treatment for retinal detachment? We searched: Medline, Embase, The Cochrane Library, and other important databases up to September 2013 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 14 studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review, we present information relating to the effectiveness and safety of the following interventions: corticosteroids, daunorubicin, fluorouracil plus low molecular weight heparin, pneumatic retinopexy, scleral buckling, short-acting or long-acting gas tamponade, silicone oil tamponade, and vitrectomy. PMID:24807890

  12. Methylglyoxal induces tau hyperphosphorylation via promoting AGEs formation.

    PubMed

    Li, Xiao-Hong; Xie, Jia-Zhao; Jiang, Xia; Lv, Bing-Ling; Cheng, Xiang-Shu; Du, Lai-Ling; Zhang, Jia-Yu; Wang, Jian-Zhi; Zhou, Xin-Wen

    2012-12-01

    The hyperphosphorylated tau is a major protein component of neurofibrillary tangle, which is one of hallmarks of Alzheimer's disease (AD). While the level of methylglyoxal (MG) is significantly increased in the AD brains, the role of MG in tau phosphorylation is still not reported. Here, we found that MG could induce tau hyperphosphorylation at multiple AD-related sites in neuroblastoma 2a cells under maintaining normal cell viability. MG treatment increased the level of advanced glycation end products (AGEs) and the receptor of AGEs (RAGE). Glycogen synthesis kinase-3β (GSK-3β) and p38 MAPK were activated, whereas the level and activity of JNK, Erk1/2, cdk5, and PP2A were not altered after MG treatment. Simultaneous inhibition of GSK-3β or p38 attenuated the MG-induced tau hyperphosphorylation. Aminoguanidine, a blocker of AGEs formation, could effectively reverse the MG-induced tau hyperphosphorylation. These data suggest that MG induces AD-like tau hyperphosphorylation through AGEs formation involving RAGE up-regulation and GSK-3β activation and p38 activation is also partially involved in MG-induced tau hyperphosphorylation. Thus, targeting MG may be a promising therapeutic strategy to prevent AD-like tau hyperphosphorylation.

  13. Hyperphosphorylation results in tau dysfunction in DNA folding and protection.

    PubMed

    Lu, Yang; He, Hai-Jin; Zhou, Jun; Miao, Jun-Ye; Lu, Jing; He, Ying-Ge; Pan, Rong; Wei, Yan; Liu, Ying; He, Rong-Qiao

    2013-01-01

    Hyperphosphorylation of tau occurs in preclinical and clinical stages of Alzheimer's disease (AD), and hyperphosphorylated tau is the main constituent of the paired helical filaments in the brains of mild cognitive impairment and AD patients. While most of the work described so far focused on the relationship between hyperphosphorylation of tau and microtubule disassembly as well as axonal transport impairments, both phenomena ultimately leading to cell death, little work has been done to study the correlation between tau hyperphosphorylation and DNA damage. As we showed in this study, tau hyperphosphorylation and DNA damage co-occurred under formaldehyde treatment in N2a cells, indicating that phosphorylated tau (p-Tau) induced by formaldehyde may be involved in DNA impairment. After phosphorylation, the effect of tau in preventing DNA from thermal denaturation was diminished, its ability to accelerate DNA renaturation was lost, and its function in protecting DNA from reactive oxygen species (ROS) attack was impaired. Thus, p-Tau is not only associated with the disassembly of the microtubule system, but also plays a crucial role in DNA impairment. Hyperphosphorylation-mediated dysfunction of tau protein in prevention of DNA structure from damage under the attack of ROS may provide novel insights into the mechanisms underlying tauopathies.

  14. Dimethyl sulfoxide induces both direct and indirect tau hyperphosphorylation.

    PubMed

    Julien, Carl; Marcouiller, François; Bretteville, Alexis; El Khoury, Noura B; Baillargeon, Joanie; Hébert, Sébastien S; Planel, Emmanuel

    2012-01-01

    Dimethyl sulfoxide (DMSO) is widely used as a solvent or vehicle for biological studies, and for treatment of specific disorders, including traumatic brain injury and several forms of amyloidosis. As Alzheimer's disease (AD) brains are characterized by deposits of β-amyloid peptides, it has been suggested that DMSO could be used as a treatment for this devastating disease. AD brains are also characterized by aggregates of hyperphosphorylated tau protein, but the effect of DMSO on tau phosphorylation is unknown. We thus investigated the impact of DMSO on tau phosphorylation in vitro and in vivo. One hour following intraperitoneal administration of 1 or 2 ml/kg DMSO in mice, no change was observed in tau phosphorylation. However, at 4 ml/kg, tau was hyperphosphorylated at AT8 (Ser(202)/Thr(205)), PHF-1 (Ser(396)/Ser(404)) and AT180 (Thr(231)) epitopes. At this dose, we also noticed that the animals were hypothermic. When the mice were maintained normothermic, the effect of 4 ml/kg DMSO on tau hyperphosphorylation was prevented. On the other hand, in SH-SY5Y cells, 0.1% DMSO induced tau hyperphosphorylation at AT8 and AT180 phosphoepitopes in normothermic conditions. Globally, these findings demonstrate that DMSO can induce tau hyperphosphorylation indirectly via hypothermia in vivo, and directly in vitro. These data should caution researchers working with DMSO as it can induce artifactual results both in vivo and in vitro.

  15. Dimethyl Sulfoxide Induces Both Direct and Indirect Tau Hyperphosphorylation

    PubMed Central

    Julien, Carl; Marcouiller, François; Bretteville, Alexis; El Khoury, Noura B.; Baillargeon, Joanie; Hébert, Sébastien S.; Planel, Emmanuel

    2012-01-01

    Dimethyl sulfoxide (DMSO) is widely used as a solvent or vehicle for biological studies, and for treatment of specific disorders, including traumatic brain injury and several forms of amyloidosis. As Alzheimer’s disease (AD) brains are characterized by deposits of β-amyloid peptides, it has been suggested that DMSO could be used as a treatment for this devastating disease. AD brains are also characterized by aggregates of hyperphosphorylated tau protein, but the effect of DMSO on tau phosphorylation is unknown. We thus investigated the impact of DMSO on tau phosphorylation in vitro and in vivo. One hour following intraperitoneal administration of 1 or 2 ml/kg DMSO in mice, no change was observed in tau phosphorylation. However, at 4 ml/kg, tau was hyperphosphorylated at AT8 (Ser202/Thr205), PHF-1 (Ser396/Ser404) and AT180 (Thr231) epitopes. At this dose, we also noticed that the animals were hypothermic. When the mice were maintained normothermic, the effect of 4 ml/kg DMSO on tau hyperphosphorylation was prevented. On the other hand, in SH-SY5Y cells, 0.1% DMSO induced tau hyperphosphorylation at AT8 and AT180 phosphoepitopes in normothermic conditions. Globally, these findings demonstrate that DMSO can induce tau hyperphosphorylation indirectly via hypothermia in vivo, and directly in vitro. These data should caution researchers working with DMSO as it can induce artifactual results both in vivo and in vitro. PMID:22768202

  16. Effects of 3-repeat tau on taxol mobility through microtubules

    NASA Astrophysics Data System (ADS)

    Park, Hyunjoo; Fygenson, Deborah; Kim, Mahn Won

    2005-03-01

    Both the anti-cancer drug taxol and the microtubule-associated protein tau suppress dynamics of microtubules (MT). We have observed taxol mobility with full-length 3-repeat tau, one of six tau isoforms, using fluorescence recovery after photobleaching (FRAP) on MTs and compare with earlier results on recombinant full-length adult 4-repeat tau. Taxol mobility becomes highly sensitive to taxol concentration in the presence of 3-repeat tau (up to 1:1 molar ratio) as it does in the presence of 4-repeat tau, but is 2 to 3 times faster at low taxol concentrations. Fitting to a mean-field binding reaction model [J.L. Ross et.al, PNAS 101:12910-5 (2004)] suggests that the presence of 3-repeat tau enhances taxol movement through pores in the MT walls.

  17. Posterior vitreous detachment.

    PubMed

    Thimons, J J

    1992-01-01

    Posterior vitreous detachment is an expected consequence of aging, but it can also be the initiating cause of a retinal detachment. To understand the mechanism of posterior vitreous detachment and its sequelae, it is necessary to appreciate the anatomy of the vitreous, its development, and the pathogenesis of vitreous degeneration. This paper is a discussion of these considerations, the types of complications that may result from vitreous detachment, the proper examination of patients who present with the symptoms of vitreous detachment, and appropriate patient management.

  18. Dynamics of slab detachment

    NASA Astrophysics Data System (ADS)

    Duretz, T.; Schmalholz, S. M.; Gerya, T. V.

    2012-04-01

    Our study investigates the dynamics of slab detachment and evaluates the amount of time necessary for slabs to detach. We combine both the results of two-dimensional numerical modeling with the prediction of a one-dimensional analytical solution for viscous necking under gravity. This tidy suggest that the dominant deformation mechanisms leading to slab detachment is viscous necking, independently of the depth of slab detachment. Localised simple shear may also occur when the slab dip is moderate, especially in the colder parts of the slab. Brittle fracturing, or breaking, plays a minor role during the slab detachment process. 2D thermo-mechanical simulations indicate that the duration of slab detachment is short (< 4 Ma) and can occur in less than 0.5 Ma. No simple correlation between the slab detachment depth and duration was found. Our results suggest that deep slab detachments (> 250 km) can also occur within a short time (< 1 Ma). On the other hand, slab detachments taking place between 35 and 250 km depth may last less than 2 Ma. This aspect has implications for geodynamic interpretations using slab detachment as explanation for processes such as melting, exhumation or surface uplift.

  19. Morin attenuates tau hyperphosphorylation by inhibiting GSK3β

    PubMed Central

    Gong, Eun Ji; Park, Hee Ra; Kim, Mi Eun; Piao, Shunfu; Lee, Eunjin; Jo, Dong-Gyu; Chung, Hae Young; Ha, Nam-Chul; Mattson, Mark P.; Lee, Jaewon

    2011-01-01

    Alzheimer’s disease (AD) is the major form of age-related dementia and is characterized by progressive cognitive impairment, the accumulation of extracellular amyloid β-peptide (Aβ), and intracellular hyperphosphorylated tau aggregates in affected brain regions. Tau hyperphosphorylation and accumulation in neurofibrillary tangles is strongly correlated with cognitive deficits, and is apparently a critical event in the dementia process because mutations in tau can cause a tangle-only form of dementia called frontotemporal lobe dementia. Among kinases that phosphorylate tau, glycogen synthase kinase 3β (GSK3β) is strongly implicated in AD pathogenesis. In the present study, we established an ELISA to screen for agents that inhibit GSK3β activity and found that the flavonoid morin effectively inhibited GSK3β activity and blocked GSK3β-induced tau phosphorylation in vitro. In addition, morin attenuated Aβ-induced tau phosphorylation and protected human neuroblastoma cells against Aβ cytotoxicity. Furthermore, treatment of 3×Tg-AD mice with morin resulted in reductions in tau hyperphosphorylation and paired helical filament-like immunoreactivity in hippocampal neurons. Morin is a novel inhibitor of GSK3β that can reduce tau pathology in vivo and may have potential as a therapeutic agent in tauopathies. PMID:21782947

  20. Descemet membrane detachment.

    PubMed

    Mackool, R J; Holtz, S J

    1977-03-01

    Four eyes of three patients had extensive postoperative Descemet membrane (DM) detachment. Blood was present just anterior to the DM in three of the four eyes and later converted to and persisted as pigment. Haziness of the cornea at the level of the DM could be seen with reattachment. Detachments of the DM are classified as planar when there is 1 mm or less separation of the DM from its overlying stroma in all areas. Nonplanar DM detachments exceed 1 mm of separation. Planar detachments have a much better prognosis than nonplanar detachments do, with or without descemetopexy. Repair of DM detachments, when necessary, should include air injection, with the lease possible instrumentation of the DM.

  1. Retinal detachment repair

    MedlinePlus

    Scleral buckling; Vitrectomy; Pneumatic retinopexy; Laser retinopexy; Rhegmatogenous retinal detachment repair ... it meets the hole in the retina. Scleral buckling can be done using numbing medicine while you ...

  2. Modeling of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Popov, Dmitri

    1997-01-01

    Our long term goal is to develop techniques to achieve detached solidification reliably and reproducibly, in order to produce crystals with fewer defects. To achieve this goal it is necessary to understand thoroughly the physics of detached solidification. It was the primary objective of the current project to make progress toward this complete understanding. 'Me products of this grant are attached. These include 4 papers and a preliminary survey of the observations of detached solidification in space. We have successfully modeled steady state detached solidification, examined the stability of detachment, and determined the influence of buoyancy-driven convection under different conditions. Directional solidification in microgravity has often led to ingots that grew with little or no contact with the ampoule wall. When this occurred, crystallographic perfection was usually greatly improved -- often by several orders of magnitude. Indeed, under the Soviet microgravity program the major objective was to achieve detached solidification with its resulting improvement in perfection and properties. Unfortunately, until recently the true mechanisms underlying detached solidification were unknown. As a consequence, flight experiments yielded erratic results. Within the past three years, we have developed a new theoretical model that explains many of the flight results. This model gives rise to predictions of the conditions required to yield detached solidification.

  3. Hyperphosphorylation regulates the activity of SREBP1 during mitosis.

    PubMed

    Bengoechea-Alonso, Maria T; Punga, Tanel; Ericsson, Johan

    2005-08-16

    The sterol regulatory element-binding protein (SREBP) family of transcription factors controls the biosynthesis of cholesterol and other lipids, and lipid synthesis is critical for cell growth and proliferation. We were, therefore, interested in the expression and activity of SREBPs during the cell cycle. We found that the expression of a number of SREBP-responsive promoter-reporter genes were induced in a SREBP-dependent manner in cells arrested in G2/M. In addition, the mature forms of SREBP1a and SREBP1c were hyperphosphorylated in mitotic cells, giving rise to a phosphoepitope recognized by the mitotic protein monoclonal-2 (MPM-2) antibody. In contrast, SREBP2 was not hyperphosphorylated in mitotic cells and was not recognized by the MPM-2 antibody. The MPM-2 epitope was mapped to the C terminus of mature SREBP1, and the mitosis-specific hyperphosphorylation of SREBP1 depended on this domain of the protein. The transcriptional and DNA-binding activity of SREBP1 was enhanced in cells arrested in G2/M, and these effects depended on the C-terminal domain of the protein. In part, these effects could be explained by our observation that mature SREBP1 was stabilized in G2/M. In agreement with these observations, we found that the synthesis of cholesterol was increased in G2/M-arrested cells. Thus, our results demonstrate that the activity of mature SREBP1 is regulated by phosphorylation during the cell cycle, suggesting that SREBP1 may provide a link between lipid synthesis, proliferation, and cell growth.

  4. Divertor plasma detachment

    SciTech Connect

    Krasheninnikov, S. I.; Kukushkin, A. S.; Pshenov, A. A.

    2016-05-15

    Regime with the plasma detached from the divertor targets (detached divertor regime) is a natural continuation of the high recycling conditions to higher density and stronger impurity radiation loss. Both the theoretical considerations and experimental data show clearly that the increase of the impurity radiation loss and volumetric plasma recombination causes the rollover of the plasma flux to the target when the density increases, which is the manifestation of detachment. Plasma-neutral friction (neutral viscosity effects), although important for the sustainment of high density/pressure plasma upstream and providing the conditions for efficient recombination and power loss, is not directly involved in the reduction of the plasma flux to the targets. The stability of detachment is also discussed.

  5. Divertor plasma detachment

    NASA Astrophysics Data System (ADS)

    Krasheninnikov, S. I.; Kukushkin, A. S.; Pshenov, A. A.

    2016-05-01

    Regime with the plasma detached from the divertor targets (detached divertor regime) is a natural continuation of the high recycling conditions to higher density and stronger impurity radiation loss. Both the theoretical considerations and experimental data show clearly that the increase of the impurity radiation loss and volumetric plasma recombination causes the rollover of the plasma flux to the target when the density increases, which is the manifestation of detachment. Plasma-neutral friction (neutral viscosity effects), although important for the sustainment of high density/pressure plasma upstream and providing the conditions for efficient recombination and power loss, is not directly involved in the reduction of the plasma flux to the targets. The stability of detachment is also discussed.

  6. Retinal detachment repair - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100132.htm Retinal detachment repair - series—Normal anatomy To use the ... to slide 6 out of 6 Overview The retina is the internal layer of the eye that ...

  7. Retinal detachment in pseudophakia.

    PubMed

    Galin, M A; Poole, T A; Obstbaum, S A

    1979-07-01

    In a series of cataract patients excluding myopic individuals, under age 60 years, and cases in which vitreous loss occurred, retinal detachment was no less frequent after intracapsular cataract extraction and Sputnik iris supported lenses than in controls. Both groups were followed up for a minimum of two years. The detachments predominantly occurred from retinal breaks in areas of the retina that looked normal preoperatively.

  8. Pharmacotherapies for Retinal Detachment.

    PubMed

    Wubben, Thomas J; Besirli, Cagri G; Zacks, David N

    2016-07-01

    Retinal detachment is an important cause of visual loss. Currently, surgical techniques, including vitrectomy, scleral buckle, and pneumatic retinopexy, are the only means to repair retinal detachment and restore vision. However, surgical failure rates may be as high as 20%, and visual outcomes continue to vary secondary to multiple processes, including postoperative cystoid macular edema, epiretinal membrane formation, macular folds, and, ultimately, photoreceptor death. Therefore, pharmacotherapies are being sought to aid the success rates of modern surgical techniques and reduce or slow the degeneration of photoreceptors during retinal detachment. This review discusses potential therapeutic avenues that aid in retinal reattachment, reduce the rate of retinal redetachment by limiting proliferative vitreoretinopathy, and protect against photoreceptor cell death.

  9. Detached rock evaluation device

    DOEpatents

    Hanson, David R.

    1986-01-01

    A rock detachment evaluation device (10) having an energy transducer unit 1) for sensing vibrations imparted to a subject rock (172) for converting the sensed vibrations into electrical signals, a low band pass filter unit (12) for receiving the electrical signal and transmitting only a low frequency segment thereof, a high band pass filter unit (13) for receiving the electrical signals and for transmitting only a high frequency segment thereof, a comparison unit (14) for receiving the low frequency and high frequency signals and for determining the difference in power between the signals, and a display unit (16) for displaying indicia of the difference, which provides a quantitative measure of rock detachment.

  10. Plasma detachment in linear devices

    NASA Astrophysics Data System (ADS)

    Ohno, N.

    2017-03-01

    Plasma detachment research in linear devices, sometimes called divertor plasma simulators, is reviewed. Pioneering works exploring the concept of plasma detachment were conducted in linear devices. Linear devices have contributed greatly to the basic understanding of plasma detachment such as volume plasma recombination processes, detached plasma structure associated with particle and energy transport, and other related issues including enhancement of convective plasma transport, dynamic response of plasma detachment, plasma flow reversal, and magnetic field effect. The importance of plasma detachment research using linear devices will be highlighted aimed at the design of future DEMO.

  11. The symbol detachment problem.

    PubMed

    Pezzulo, Giovanni; Castelfranchi, Cristiano

    2007-06-01

    In situated and embodied approaches it is commonly assumed that the dynamics of sensorimotor engagement between an adaptive agent and its environment are crucial in understanding natural cognition. This perspective permits to address the symbol grounding problem, since the aboutness of any mental state arising during agent-environment engagement is guaranteed by their continuous coupling. However, cognitive agents are also able to formulate representations that are detached from the current state of affairs, such as expectations and goals. Moreover, they can act on their representations before--or instead of--acting directly on the environment, for example building the plan of a bridge and not directly the bridge. On the basis of representations, actions such as planning, remembering or imagining are possible that are disengaged from the current sensorimotor cycle, and often functional to future-oriented conducts. A new problem thus has to be acknowledged, the symbol detachment problem: how and why do situated agents develop representations that are detached from their current sensorimotor interaction, but nevertheless preserve grounding and aboutness? How do cognitive agents progressively acquire a range of capabilities permitting them to deal not only with the current situation but also with alternative, in particular future states of affairs? How do they develop the capability of acting on their representations instead of acting directly on the world? In a theoretical and developmental perspective, we propose that anticipation plays a crucial role in the detachment process: anticipatory representations, originally detached from the sensorimotor cycle for the sake of action control, are successively exapted for bootstrapping increasingly complex cognitive capabilities.

  12. Oligomer formation of tau protein hyperphosphorylated in cells.

    PubMed

    Tepper, Katharina; Biernat, Jacek; Kumar, Satish; Wegmann, Susanne; Timm, Thomas; Hübschmann, Sabrina; Redecke, Lars; Mandelkow, Eva-Maria; Müller, Daniel J; Mandelkow, Eckhard

    2014-12-05

    Abnormal phosphorylation ("hyperphosphorylation") and aggregation of Tau protein are hallmarks of Alzheimer disease and other tauopathies, but their causative connection is still a matter of debate. Tau with Alzheimer-like phosphorylation is also present in hibernating animals, mitosis, or during embryonic development, without leading to pathophysiology or neurodegeneration. Thus, the role of phosphorylation and the distinction between physiological and pathological phosphorylation needs to be further refined. So far, the systematic investigation of highly phosphorylated Tau was difficult because a reliable method of preparing reproducible quantities was not available. Here, we generated full-length Tau (2N4R) in Sf9 cells in a well defined phosphorylation state containing up to ∼20 phosphates as judged by mass spectrometry and Western blotting with phospho-specific antibodies. Despite the high concentration in living Sf9 cells (estimated ∼230 μm) and high phosphorylation, the protein was not aggregated. However, after purification, the highly phosphorylated protein readily formed oligomers, whereas fibrils were observed only rarely. Exposure of mature primary neuronal cultures to oligomeric phospho-Tau caused reduction of spine density on dendrites but did not change the overall cell viability. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Zinc Binding Directly Regulates Tau Toxicity Independent of Tau Hyperphosphorylation

    PubMed Central

    Huang, Yunpeng; Wu, Zhihao; Cao, Yu; Lang, Minglin; Lu, Bingwei; Zhou, Bing

    2015-01-01

    SUMMARY Tau hyperphosphorylation is thought to underlie tauopathy. Working in a Drosophila tauopathy model expressing a human Tau mutant (hTauR406W, or Tau*), we show that zinc contributes to the development of Tau toxicity through two independent actions: by increasing Tau phosphorylation and, more significantly, by directly binding to Tau. Elimination of zinc binding through amino acid substitution of Cys residues has a minimal effect on phosphorylation levels yet essentially eliminates Tau toxicity. The toxicity of the zinc-binding-deficient mutant Tau* (Tau*C2A) and overexpression of native Drosophila Tau, also lacking the corresponding zinc-binding Cys residues, are largely impervious to zinc concentration. Importantly, restoration of zinc-binding ability to Tau* by introduction of a zinc-binding residue (His) into the original Cys positions restores zinc-responsive toxicities in proportion to zinc-binding affinities. These results indicate zinc binding is a substantial contributor to tauopathy and have implications for therapy development. PMID:25066125

  14. Hyperphosphorylated tau is implicated in acquired epilepsy and neuropsychiatric comorbidities.

    PubMed

    Zheng, Ping; Shultz, Sandy R; Hovens, Chris M; Velakoulis, Dennis; Jones, Nigel C; O'Brien, Terence J

    2014-06-01

    Epilepsy is a common group of neurological diseases. Acquired epilepsy can be caused by brain insults, such as trauma, infection or tumour, and followed by a latent period from several months to years before the emergence of recurrent spontaneous seizures. More than 50% of epilepsy cases will develop chronic neurodegenerative, neurocognitive and neuropsychiatric comorbidities. It is important to understand the mechanisms by which a brain insult results in acquired epilepsy and comorbidities in order to identify targets for novel therapeutic interventions that may mitigate these outcomes. Recent studies have implicated the hyperphosphorylated tubulin-associated protein (tau) in rodent models of epilepsy and Alzheimer's disease, and in experimental and clinical studies of traumatic brain injury. This potentially represents a novel target to mitigate epilepsy and associated neurocognitive and psychiatric disorders post-brain injury. This article reviews the potential role of tau-based mechanisms in the pathophysiology of acquired epilepsy and its neurocognitive and neuropsychiatric comorbidities, and the potential to target these for novel disease-modifying treatments.

  15. Tau hyperphosphorylation in apolipoprotein E-deficient and control mice after closed head injury.

    PubMed

    Genis, L; Chen, Y; Shohami, E; Michaelson, D M

    2000-05-15

    Apolipoprotein E (apoE)-deficient mice have learning and memory impairments that are associated with specific neurochemical changes and hyperphosphorylation of distinct epitopes of the cytoskeletal protein tau. Furthermore, such mice are highly susceptible to the sequelae of brain trauma and their ability to recover from head injury is impaired. In the present study we investigated the extent that the neuronal maintenance and repair impairments of apoE-deficient mice are related to aberrations at the tau phosphorylation level. This was pursued by subjecting control and apoE-deficient mice to closed head injury (CHI) and examination, utilizing immunoblot assays, of the resulting effects on tau phosphorylation. The results thus obtained revealed that tau of apoE-deficient mice is hyperphosphorylated before CHI and that this insult results in transient tau hyperphosphorylation, whose extent and time course in the two mouse groups varied markedly. Tau hyperphosphorylation in the injured controls was maximal by about 4 hr after injury and reverted to basal levels by 24 hr. In contrast, almost no head injury-induced tau hyperphosphorylation was observed in the apoE-deficient mice at 4 hr after injury. Some tau hyper-phosphorylation was detected in the head-injured apoE-deficient mice after longer time intervals, but its extent was markedly lower than the maximal values obtained in the head injured controls. These findings show that the chronic neuronal impairments brought about by apoE deficiency and the acute response to head injury are both associated with hyperphosphorylation of the same tau domain and that the ability of apoE-deficient mice to mount the acute tau hyperphosphorylation response to head injury is impaired.

  16. Immunological memory to hyperphosphorylated tau in asymptomatic individuals.

    PubMed

    Pascual, Gabriel; Wadia, Jehangir S; Zhu, Xueyong; Keogh, Elissa; Kükrer, Başak; van Ameijde, Jeroen; Inganäs, Hanna; Siregar, Berdien; Perdok, Gerrard; Diefenbach, Otto; Nahar, Tariq; Sprengers, Imke; Koldijk, Martin H; der Linden, Els C Brinkman-van; Peferoen, Laura A; Zhang, Heng; Yu, Wenli; Li, Xinyi; Wagner, Michelle; Moreno, Veronica; Kim, Julie; Costa, Martha; West, Kiana; Fulton, Zara; Chammas, Lucy; Luckashenak, Nancy; Fletcher, Lauren; Holland, Trevin; Arnold, Carrie; Anthony Williamson, R; Hoozemans, Jeroen J; Apetri, Adrian; Bard, Frederique; Wilson, Ian A; Koudstaal, Wouter; Goudsmit, Jaap

    2017-05-01

    Several reports have described the presence of antibodies against Alzheimer's disease-associated hyperphosphorylated forms of tau in serum of healthy individuals. To characterize the specificities that can be found, we interrogated peripheral IgG(+) memory B cells from asymptomatic blood donors for reactivity to a panel of phosphorylated tau peptides using a single-cell screening assay. Antibody sequences were recovered, cloned, and expressed as full-length IgGs. In total, 52 somatically mutated tau-binding antibodies were identified, corresponding to 35 unique clonal families. Forty-one of these antibodies recognize epitopes in the proline-rich and C-terminal domains, and binding of 26 of these antibodies is strictly phosphorylation dependent. Thirteen antibodies showed inhibitory activity in a P301S lysate seeded in vitro tau aggregation assay. Two such antibodies, CBTAU-7.1 and CBTAU-22.1, which bind to the proline-rich and C-terminal regions of tau, respectively, were characterized in more detail. CBTAU-7.1 recognizes an epitope that is similar to that of murine anti-PHF antibody AT8, but has different phospho requirements. Both CBTAU-7.1 and CBTAU-22.1 detect pathological tau deposits in post-mortem brain tissue. CBTAU-7.1 reveals a similar IHC distribution pattern as AT8, immunostaining (pre)tangles, threads, and neuritic plaques. CBTAU-22.1 shows selective detection of neurofibrillary changes by IHC. Taken together, these results suggest the presence of an ongoing antigen-driven immune response against tau in healthy individuals. The wide range of specificities to tau suggests that the human immune repertoire may contain antibodies that can serve as biomarkers or be exploited for therapy.

  17. Stability of Detached Solidification

    NASA Technical Reports Server (NTRS)

    Mazuruk, K.; Volz, M. P.; Croell, A.

    2009-01-01

    Bridgman crystal growth can be conducted in the so-called "detached" solidification regime, where the growing crystal is detached from the crucible wall. A small gap between the growing crystal and the crucible wall, of the order of 100 micrometers or less, can be maintained during the process. A meniscus is formed at the bottom of the melt between the crystal and crucible wall. Under proper conditions, growth can proceed without collapsing the meniscus. The meniscus shape plays a key role in stabilizing the process. Thermal and other process parameters can also affect the geometrical steady-state stability conditions of solidification. The dynamic stability theory of the shaped crystal growth process has been developed by Tatarchenko. It consists of finding a simplified autonomous set of differential equations for the radius, height, and possibly other process parameters. The problem then reduces to analyzing a system of first order linear differential equations for stability. Here we apply a modified version of this theory for a particular case of detached solidification. Approximate analytical formulas as well as accurate numerical values for the capillary stability coefficients are presented. They display an unexpected singularity as a function of pressure differential. A novel approach to study the thermal field effects on the crystal shape stability has been proposed. In essence, it rectifies the unphysical assumption of the model that utilizes a perturbation of the crystal radius along the axis as being instantaneous. It consists of introducing time delay effects into the mathematical description and leads, in general, to stability over a broader parameter range. We believe that this novel treatment can be advantageously implemented in stability analyses of other crystal growth techniques such as Czochralski and float zone methods.

  18. Model of detached plasmas

    SciTech Connect

    Yoshikawa, S.; Chance, M.

    1986-07-01

    Recently a tokamak plasma was observed in TFTR that was not limited by a limiter or a divertor. A model is proposed to explain this equilibrium, which is called a detached plasma. The model consists of (1) the core plasma where ohmic heating power is lost by anomalous heat conduction and (2) the shell plasma where the heat from the core plasma is radiated away by the atomic processes of impurity ions. A simple scaling law is proposed to test the validity of this model.

  19. On detachment asymmetry and stability

    NASA Astrophysics Data System (ADS)

    Pshenov, A. A.; Kukushkin, A. S.; Krasheninnikov, S. I.

    2017-07-01

    Three issues related to the physics of divertor detachment are analyzed in detail: the criteria for the onset of complete divertor detachment, the role of neutrals in "symmetryzation" of detachment in the inner and outer divertors, and the transition to divertor detachment. The results of comprehensive 2D numerical simulations with the SOLPS4.3 package are compared with some experimental data and predictions based on simplified analytical models. It is shown that it is the ratio of the upstream plasma pressure to the specific power flux entering the recycling region that controls the local onset of detachment on a specific flux tube. Pup/qreclycl≥(Pup/qreclycl) crit remains the valid criterion also in the presence of seeded impurity, if the impurity radiation and hydrogen recycling regions are spatially separated. Detailed analysis indicates that the reverse plasma flow forming on the most heat loaded flux tubes in the outer divertor under the influence of the neutrals coming from the deeply detached inner divertor plays the key role in the detachment "symmetryzation" and allows the outer divertor to reach the detached regime. Finally, it is demonstrated that a gradual increase of the perpendicular heat transport in the edge plasma during transition to the detached regime can make this transition bifurcation-like.

  20. The Ambiguous Relationship of Oxidative Stress, Tau Hyperphosphorylation, and Autophagy Dysfunction in Alzheimer's Disease

    PubMed Central

    Liu, Zhenzhen; Li, Tao; Li, Ping; Wei, Nannan; Zhao, Zhiquan; Liang, Huimin; Ji, Xinying; Chen, Wenwu; Xue, Mengzhou; Wei, Jianshe

    2015-01-01

    Alzheimer's disease (AD) is the most common form of dementia. The pathological hallmarks of AD are amyloid plaques [aggregates of amyloid-beta (Aβ)] and neurofibrillary tangles (aggregates of tau). Growing evidence suggests that tau accumulation is pathologically more relevant to the development of neurodegeneration and cognitive decline in AD patients than Aβ plaques. Oxidative stress is a prominent early event in the pathogenesis of AD and is therefore believed to contribute to tau hyperphosphorylation. Several studies have shown that the autophagic pathway in neurons is important under physiological and pathological conditions. Therefore, this pathway plays a crucial role for the degradation of endogenous soluble tau. However, the relationship between oxidative stress, tau protein hyperphosphorylation, autophagy dysregulation, and neuronal cell death in AD remains unclear. Here, we review the latest progress in AD, with a special emphasis on oxidative stress, tau hyperphosphorylation, and autophagy. We also discuss the relationship of these three factors in AD. PMID:26171115

  1. Kinesin-1 transport reductions enhance human tau hyperphosphorylation, aggregation and neurodegeneration in animal models of tauopathies.

    PubMed

    Falzone, Tomás L; Gunawardena, Shermali; McCleary, David; Reis, Gerald F; Goldstein, Lawrence S B

    2010-11-15

    Neurodegeneration induced by abnormal hyperphosphorylation and aggregation of the microtubule-associated protein tau defines neurodegenerative tauopathies. Destabilization of microtubules by loss of tau function and filament formation by toxic gain of function are two mechanisms suggested for how abnormal tau triggers neuronal loss. Recent experiments in kinesin-1 deficient mice suggested that axonal transport defects can initiate biochemical changes that induce activation of axonal stress kinase pathways leading to abnormal tau hyperphosphorylation. Here we show using Drosophila and mouse models of tauopathies that reductions in axonal transport can exacerbate human tau protein hyperphosphorylation, formation of insoluble aggregates and tau-dependent neurodegeneration. Together with previous work, our results suggest that non-lethal reductions in axonal transport, and perhaps other types of minor axonal stress, are sufficient to induce and/or accelerate abnormal tau behavior characteristic of Alzheimer's disease and other neurodegenerative tauopathies.

  2. Role of NMDA receptors in noise-induced tau hyperphosphorylation in rat hippocampus and prefrontal cortex.

    PubMed

    Li, Kang; Jia, Hengchuan; She, Xiaojun; Cui, Bo; Zhang, Na; Chen, Xuewei; Xu, Chuanxiang; An, Gaihong; Ma, Qiang

    2014-05-15

    Chronic noise exposure has been associated with abnormalities in glutamate (Glu)-NMDAR signaling and tau hyperphosphorylation. However, further studies are necessary to clarify potential causal relationships. The aim of the present study was to evaluate the role of NMDA receptors in noise-induced tau hyperphosphorylation in the rat hippocampus and prefrontal cortex. Male Wistar rats were randomly divided into three groups in the present study: control with isotonic saline instillation (n=10); noise exposure (100 dB SPL white noise, 4h/d × 14d) and treated with saline (n=10); and noise exposure and treated with MK-801 (0.5mg/kg, intraperitoneally; n=10). The levels of tau phosphorylated at Ser202 and Ser396, and proteins involved in hyperphosphorylation, namely glycogen synthase kinase 3β (GSK3β) and protein phosphatase 2A (PP2A), were measured in the hippocampus and prefrontal cortex (PFC) after the last noise exposure. We showed that phosphorylated tau levels were enhanced in noise-exposed-rat hippocampus and PFC. MK-801 decreased the hyperphosphorylation of tau at Ser202 and Ser396 sites in the hippocampus and PFC. Furthermore, MK-801 reversed noise-induced GSK3β overexpression but had no significant effect on PP2A levels. This suggests that MK-801 protects against chronic-noise-induced tau hyperphosphorylation in the hippocampus and PFC. These findings demonstrate that Glu-NMDAR signaling may be involved in triggering aberrant tau hyperphosphorylation in the hippocampus and PFC after chronic noise exposure.

  3. Controlling marginally detached divertor plasmas

    DOE PAGES

    Eldon, David; Kolemen, Egemen; Barton, Joseph L.; ...

    2017-05-04

    A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as Te = 5 eV near the divertor target plate), the resulting Te profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in and it handles ELMing plasmas by using real time Dα measurements to remove during-ELM slices from real time Te measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM Te is passed to a PID (proportionalintegral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate. However, the observed bifurcation in plasma conditions at the outer strike point with the ion B ×more » $$\

  4. PIMASERTIB AND SEROUS RETINAL DETACHMENTS

    PubMed Central

    AlAli, Alaa; Bushehri, Ahmad; Park, Jonathan C.; Krema, Hatem

    2016-01-01

    Purpose: To report a case of multifocal serous retinal detachments associated with pimasertib. Methods: The authors report a 26-year-old patient who developed bilateral multifocal serous retinal detachments appearing 2 days after starting pimasertib (as part of a clinical trial investigating its use in low-grade metastatic ovarian cancer) and rapidly resolving 3 days after stopping it. Conclusion: The mechanism of MEK inhibitor induced visual toxicity remains unclear. The pathophysiology of multifocal serous retinal detachments as a complication of pimasertib is still poorly understood. PMID:26444523

  5. Shock detachment from curved wedges

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-03-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  6. Shock detachment from curved wedges

    NASA Astrophysics Data System (ADS)

    Mölder, S.

    2017-09-01

    Curved shock theory is used to show that the flow behind attached shocks on doubly curved wedges can have either positive or negative post-shock pressure gradients depending on the freestream Mach number, the wedge angle and the two wedge curvatures. Given enough wedge length, the flow near the leading edge can choke to force the shock to detach from the wedge. This local choking can preempt both the maximum deflection and the sonic criteria for shock detachment. Analytical predictions for detachment by local choking are supported by CFD results.

  7. Puerarin Ameliorates D-Galactose Induced Enhanced Hippocampal Neurogenesis and Tau Hyperphosphorylation in Rat Brain.

    PubMed

    Hong, Xiao-Ping; Chen, Tao; Yin, Ni-Na; Han, Yong-Ming; Yuan, Fang; Duan, Yan-Jun; Shen, Feng; Zhang, Yan-Hong; Chen, Ze-Bin

    2016-01-01

    Enhanced neurogenesis has been reported in the hippocampus of patients with Alzheimer's disease (AD), the most common neurodegenerative disorder characterized with amyloid-β (Aβ) aggregation, tau hyperphosphorylation, and progressive neuronal loss. Previously we reported that tau phosphorylation played an essential role in adult hippocampal neurogenesis, and activation of glycogen synthase kinase (GSK-3), a crucial tau kinase, could induce increased hippocampal neurogenesis. In the present study, we found that treatment of D-galactose rats with Puerarin could significantly improve behavioral performance and ameliorate the enhanced neurogenesis and microtubule-associated protein tau hyperphosphorylation in the hippocampus of D-galactose rat brains. FGF-2/GSK-3 signaling pathway might be involved in the effects of Puerarin on hippocampal neurogenesis and tau hyperphosphorylation. Our finding provides primary in vivo evidence that Puerarin can attenuate AD-like enhanced hippocampal neurogenesis and tau hyperphosphorylation. Our finding also suggests Puerarin can be served as a treatment for age-related neurodegenerative disorders, such as AD.

  8. Escitalopram Ameliorates Forskolin-Induced Tau Hyperphosphorylation in HEK239/tau441 Cells.

    PubMed

    Ren, Qing-Guo; Wang, Yan-Juan; Gong, Wei-Gang; Zhou, Qi-Da; Xu, Lin; Zhang, Zhi-Jun

    2015-06-01

    To investigate the effect of escitalopram (a widely used and highly efficacious antidepressant from the SSRI class) on tau hyperphosphorylation, HEK293/tau441 cells were pretreated with 4 μM of forskolin for 2 h. Then we treated the cells with different doses of escitalopram (0, 5, 10, 20, 40, 80 μM) for 22 h. We measured the phosphorylation level of tau by Western blotting. It was shown that escitalopram could protect tau from hyperphosphorylation induced by pharmacological activation of protein kinase A (PKA) at a dose of 20, 40, and 80 μM in vitro. Interestingly, the same dose of escitalopram could also increase the level of serine-9-phosphorylated GSK-3β (inactive form) and the phosphorylation level of Akt at Ser473 (active form) with no significant change in the level of total GSK-3β and Akt. Unexpectedly, 5-hydroxytryptamine 1A receptor (5-HT1A) agonist 8-OH-DPAT did not decrease forskolin-induced tau hyperphosphorylation. Our results suggest that escitalopram can ameliorate forskolin-induced tau hyperphosphorylation, which is not through the typical 5-HT1A pathway, and Akt/GSK-3β signaling pathway is involved. These findings may support an effective role of antidepressants in the prevention of dementia associated with depression in patients.

  9. Hyperphosphorylation amplifies UPF1 activity to resolve stalls in nonsense-mediated mRNA decay

    PubMed Central

    Durand, Sébastien; Franks, Tobias M.; Lykke-Andersen, Jens

    2016-01-01

    Many gene expression factors contain repetitive phosphorylation sites for single kinases, but the functional significance is poorly understood. Here we present evidence for hyperphosphorylation as a mechanism allowing UPF1, the central factor in nonsense-mediated decay (NMD), to increasingly attract downstream machinery with time of residence on target mRNAs. Indeed, slowing NMD by inhibiting late-acting factors triggers UPF1 hyperphosphorylation, which in turn enhances affinity for factors linking UPF1 to decay machinery. Mutational analyses reveal multiple phosphorylation sites contributing to different extents to UPF1 activity with no single site being essential. Moreover, the ability of UPF1 to undergo hyperphosphorylation becomes increasingly important for NMD when downstream factors are depleted. This hyperphosphorylation-dependent feedback mechanism may serve as a molecular clock ensuring timely degradation of target mRNAs while preventing degradation of non-targets, which, given the prevalence of repetitive phosphorylation among central gene regulatory factors, may represent an important general principle in gene expression. PMID:27511142

  10. Oxidative stress with tau hyperphosphorylation in memory impaired 1,2-diacetylbenzene-treated mice.

    PubMed

    Kang, Sin-Woo; Kim, Sung Jin; Kim, Min-Sun

    2017-09-05

    Long-term exposure to organic solvent may be related to the incidence of neuronal diseases, such as, Alzheimer's disease, depression, multiple sclerosis, dementia, Parkinson's disease. Previously, the authors reported 1,2-diacetylbenzene (DAB; a neurotoxic metabolite of 1,2-diethylbenzene) causes central and peripheral neuropathies that lead to motor neuronal deficits. Furthermore, it is known DAB increases oxidative stress and protein adduct levels and impairs hippocampal neurogenesis in mice. The authors examined the relevance of oxidative stress and tau hyperphosphorylation in the hippocampus. Five-week-old male C57BL/6 mice were treated with 1 or 5mg/kg/day DAB for 2weeks. Neither overall body weight increases nor behavioral differences were observed after treatment, but kidney and liver weights decreased. Increased ROS production, activated glycogen synthase kinase-3β (GSK-3β) and tau hyperphosphorylation were observed in hippocampal homogenates. To assess memory impairment, the Morris Water Maze was used. Animals in the DAB-treated groups took longer to reach the platform. Movement patterns of DAB treated mice were more complicated and their swimming speeds were lower than those of controls. When SHSY5Y neuroblastoma cells were pretreated with NAC (an antioxidant) or a GSK-3β inhibitor, the expression of active GSK-3β and tau hyperphosphorylation were reduced. These results suggest ROS produced by DAB causes tau hyperphosphorylation via GSK-3β phosphorylation and it might be related to impaired memory deficit. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. The P body protein Dcp1a is hyper-phosphorylated during mitosis.

    PubMed

    Aizer, Adva; Kafri, Pinhas; Kalo, Alon; Shav-Tal, Yaron

    2013-01-01

    Processing bodies (PBs) are non-membranous cytoplasmic structures found in all eukaryotes. Many of their components such as the Dcp1 and Dcp2 proteins are highly conserved. Using live-cell imaging we found that PB structures disassembled as cells prepared for cell division, and then began to reassemble during the late stages of cytokinesis. During the cell cycle and as cells passed through S phase, PB numbers increased. However, there was no memory of PB numbers between mother and daughter cells. Examination of hDcp1a and hDcp1b proteins by electrophoresis in mitotic cell extracts showed a pronounced slower migrating band, which was caused by hyper-phosphorylation of the protein. We found that hDcp1a is a phospho-protein during interphase that becomes hyper-phosphorylated in mitotic cells. Using truncations of hDcp1a we localized the region important for hyper-phosphorylation to the center of the protein. Mutational analysis demonstrated the importance of serine 315 in the hyper-phosphorylation process, while other serine residues tested had a minor affect. Live-cell imaging demonstrated that serine mutations in other regions of the protein affected the dynamics of hDcp1a association with the PB structure. Our work demonstrates the control of PB dynamics during the cell cycle via phosphorylation.

  12. Beta amyloid and hyperphosphorylated tau deposits in the pancreas in type 2 diabetes

    SciTech Connect

    Miklossy, J.; Miller, L.; Qing, H.; Radenovic, A.; Kis, A.; Vileno, B.; Laszlo, F.; Martins, R.N.; Waeber, G.; Mooser, V.; Bosman, F.; Khalili, K.; Darbinian, N.; McGeer, P.L.

    2008-08-25

    Strong epidemiologic evidence suggests an association between Alzheimer disease (AD) and type 2 diabetes. To determine if amyloid beta (A{beta}) and hyperphosphorylated tau occurs in type 2 diabetes, pancreas tissues from 21 autopsy cases (10 type 2 diabetes and 11 controls) were analyzed. APP and tau mRNAs were identified in human pancreas and in cultured insulinoma beta cells (INS-1) by RT-PCR. Prominent APP and tau bands were detected by Western blotting in pancreatic extracts. Aggregated A{beta}, hyperphosphorylated tau, ubiquitin, apolipoprotein E, apolipoprotein(a), IB1/JIP-1 and JNK1 were detected in Langerhans islets in type 2 diabetic patients. A{beta} was co-localized with amylin in islet amyloid deposits. In situ beta sheet formation of islet amyloid deposits was shown by infrared microspectroscopy (SIRMS). LPS increased APP in non-neuronal cells as well. We conclude that A{beta} deposits and hyperphosphorylated tau are also associated with type 2 diabetes, highlighting common pathogenetic features in neurodegenerative disorders, including AD and type 2 diabetes and suggesting that A{beta} deposits and hyperphosphorylated tau may also occur in other organs than the brain.

  13. Uncovering BRD4 hyperphosphorylation associated with cellular transformation in NUT midline carcinoma.

    PubMed

    Wang, Ranran; Cao, Xing-Jun; Kulej, Katarzyna; Liu, Wei; Ma, Tongcui; MacDonald, Margo; Chiang, Cheng-Ming; Garcia, Benjamin A; You, Jianxin

    2017-07-03

    The epigenetic reader BRD4 plays a vital role in transcriptional regulation, cellular growth control, and cell-cycle progression. Dysregulation of BRD4 function has been implicated in the pathogenesis of a wide range of cancers. However, how BRD4 is regulated to maintain its normal function in healthy cells and how alteration of this process leads to cancer remain poorly understood. In this study, we discovered that BRD4 is hyperphosphorylated in NUT midline carcinoma and identified CDK9 as a potential kinase mediating BRD4 hyperphosphorylation. Disruption of BRD4 hyperphosphorylation using both chemical and molecular inhibitors led to the repression of BRD4 downstream oncogenes and abrogation of cellular transformation. BRD4 hyperphosphorylation is also observed in other cancers displaying enhanced BRD4 oncogenic activity. Our study revealed a mechanism that may regulate BRD4 biological function through phosphorylation, which, when dysregulated, could lead to oncogenesis. Our finding points to strategies to target the aberrant BRD4 signaling specifically for cancer intervention.

  14. Discoveries of tau, abnormally hyperphosphorylated tau and others of neurofibrillary degeneration: a personal historical perspective.

    PubMed

    Iqbal, Khalid; Grundke-Iqbal, Inge

    2006-01-01

    Alzheimer disease was described by Alois Alzheimer in 1907, but it was not until approximately 60-70 years later that any new significant developments were reported on the pathology of this disease. The discoveries that laid down the foundation for the exciting research that has been carried out during the last approximately 20 years and that have significantly enhanced our understanding of the disease are the ultrastructure of neurofibrillary tangles and neuritic (senile) plaques, the clinical-pathological correlation of these lesions to the presence of dementia, and the bulk isolation and protein composition of paired helical filaments and plaque amyloid. We discovered tau as the major protein subunit of paired helical filaments/neurofibrillary tangles, the abnormal hyperphosphorylation of this protein in this lesion and in Alzheimer brain cytosol and the gain of toxic function by the cytosolic abnormally hyperphosphorylated tau in Alzheimer brain. Here we present a personal historical account of the work in our laboratories that led, in 1986, to the discoveries of tau and its abnormal hyperphosphorylation in paired helical filaments and Alzheimer brain cytosol. This article also describes several major findings which subsequently resulted from the abnormal hyperphosphorylation of tau and in a large part account for the current understanding of the role of this lesion in Alzheimer disease and other tauopathies.

  15. Controlling marginally detached divertor plasmas

    NASA Astrophysics Data System (ADS)

    Eldon, D.; Kolemen, E.; Barton, J. L.; Briesemeister, A. R.; Humphreys, D. A.; Leonard, A. W.; Maingi, R.; Makowski, M. A.; McLean, A. G.; Moser, A. L.; Stangeby, P. C.

    2017-06-01

    A new control system at DIII-D has stabilized the inter-ELM detached divertor plasma state for H-mode in close proximity to the threshold for reattachment, thus demonstrating the ability to maintain detachment with minimal gas puffing. When the same control system was instead ordered to hold the plasma at the threshold (here defined as T e  =  5 eV near the divertor target plate), the resulting T e profiles separated into two groups with one group consistent with marginal detachment, and the other with marginal attachment. The plasma dithers between the attached and detached states when the control system attempts to hold at the threshold. The control system is upgraded from the one described in Kolemen et al (2015 J. Nucl. Mater. 463 1186) and it handles ELMing plasmas by using real time D α measurements to remove during-ELM slices from real time T e measurements derived from divertor Thomson scattering. The difference between measured and requested inter-ELM T e is passed to a PID (proportional-integral-derivative) controller to determine gas puff commands. While some degree of detachment is essential for the health of ITER’s divertor, more deeply detached plasmas have greater radiative losses and, at the extreme, confinement degradation, making it desirable to limit detachment to the minimum level needed to protect the target plate (Kolemen et al 2015 J. Nucl. Mater. 463 1186). However, the observed bifurcation in plasma conditions at the outer strike point with the ion B   ×  \

  16. The North Cycladic Detachment System

    NASA Astrophysics Data System (ADS)

    Jolivet, Laurent; Lecomte, Emmanuel; Huet, Benjamin; Denèle, Yoann; Lacombe, Olivier; Labrousse, Loïc; Le Pourhiet, Laetitia; Mehl, Caroline

    2010-01-01

    Low-angle normal faults accommodate a large part of continental post-orogenic extension. Besides the intrinsic rheological characteristics of the continental crust that may lead to the formation of shallow-dipping shear zones at the brittle-ductile transition, the role of pre-existing low-angle structures such as large thrusts has been proposed by several authors. We explore this question with the example of the North Cycladic Detachment System (NCDS) that is composed of a series of distinct detachments cropping out on the islands of Andros, Tinos and Mykonos, separating the Cycladic Blueschists in the footwall from the Upper Cycladic Nappe in the hanging wall. We show that these extensional structures are part of a single large-scale structure (more than 200 km along strike) that reactivates the Vardar suture zone. It extends eastward on Ikaria and westward offshore Evia and Thessalia where it probably connects to recent shallow-dipping normal faults evidenced on published seismic reflection profiles. The NCDS started its activity in the Oligocene concommitantly with the Aegean extension, and was still active in the Late Miocene. It has exhumed a series of metamorphic domes from southern Evia to Mykonos below low-angle detachment systems, made of low-angle normal faults and low-angle ductile shear zones. The ductile shear zones and the faults were created with a low dip and they kept the same attitude throughout their exhumation. We identify three main detachments that are part of a continuum of extension on the NCDS : Tinos detachment, Livada detachment and Mykonos detachment. A fourth detachment (Vari detachment) is the reactivation of an Eocene exhumation-related structure. Deformation in the footwall is characterized by intense stretching and flattening. Using the spatial evolution observed along strike from Andros to Mykonos we construct a history of formation of the NCDS starting with the reactivation of former thrusts leading to the exhumation of high

  17. [Surgical managment of retinal detachment].

    PubMed

    Haritoglou, C; Wolf, A

    2015-05-01

    The detachment of the neurosensory retina from the underlying retinal pigment epithelium can be related to breaks of the retina allowing vitreous fluid to gain access to the subretinal space, to exudative changes of the choroid such as tumours or inflammatory diseases or to excessive tractional forces exerted by interactions of the collagenous vitreous and the retina. Tractional retinal detachment is usually treated by vitrectomy and exudative detachment can be addressed by treatment of the underlying condition in many cases. In rhegmatogenous retinal detachment two different surgical procedures, vitrectomy and scleral buckling, can be applied for functional and anatomic rehabilitation of our patients. The choice of the surgical procedure is not really standardised and often depends on the experience of the surgeon and other more ocular factors including lens status, the number of retinal breaks, the extent of the detachment and the amount of preexisting PVR. Using both techniques, anatomic success rates of over 90 % can be achieved. Especially in young phakic patients scleral buckling offers the true advantage to prevent the progression of cataract formation requiring cataract extraction and intraocular lens implantation. Therefore, scleral buckling should be considered in selected cases as an alternative surgical option in spite of the very important technical refinements in modern vitrectomy techniques. Georg Thieme Verlag KG Stuttgart · New York.

  18. Rhegmatogenous retinal detachment treatment guidelines.

    PubMed

    García-Arumí, J; Martínez-Castillo, V; Boixadera, A; Blasco, H; Marticorena, J; Zapata, M Á; Macià, C; Badal, J; Distéfano, L; Rafart, J M; Berrocal, M; Zambrano, A; Ruíz-Moreno, J M; Figueroa, M S

    2013-01-01

    This paper outlines general guidelines following the initial diagnosis of rhegmatogenous retinal detachment. These include preoperative evaluation, treatment, possible intra- and post-operative complications, retinal re-detachment, and all therapeutic options available for each case. Treatment of the traumatic retinal detachment is also described, due to its importance and peculiarities. Treatment or prophylactic guidelines are suggested for the different types of retinal detachment described. These are based on both the experience of the ophthalmologists that have participated in preparing the guidelines, and also on evidence-based grading linked to bibliographical sources. However, these guidelines should not be interpreted as being mandatory. Given that there is a wide spectrum of options for treatment of retinal detachment, the surgeons' experience with one or other surgical technique will be of utmost importance in obtaining the best surgical result. As guidelines, they are intended as an additional aid to the surgeon during the decision-making process, with the expectation that the final choice will still be left to the surgeon's judgment and past experience.

  19. Plasma Detachment Study in VASIMR

    NASA Astrophysics Data System (ADS)

    Ilin, A. V.; Díaz, F. R. Chang; Squire, J. P.; Breizman, B. N.; Novakovski, S. V.; Sagdeev, R. Z.

    2000-10-01

    We present kinetic and MHD simulations of plasma detachment in the exhaust of the Variable Specific Impulse Magnetoplasma Rocket (VASIMR). The detachment is associated with a transition from subalfvenic to superalfvenic plasma flow in the magnetic nozzle. As a result, the kinetic energy of the outgoing plasma flow is greater than the magnetic field energy in the exhaust area, so that the plasma is no longer confined by the magnetic field. We model the outgoing plasma flow under the assumptions that the plasma is collisionless and has a constant electron temperature. Particle simulations show that the ion motion may become nonadiabatic in the exhaust area as the magnetic field decreases downstream. This effect should facilitate the detachment.

  20. Activation of asparaginyl endopeptidase leads to Tau hyperphosphorylation in Alzheimer disease.

    PubMed

    Basurto-Islas, Gustavo; Grundke-Iqbal, Inge; Tung, Yunn Chyn; Liu, Fei; Iqbal, Khalid

    2013-06-14

    Neurofibrillary pathology of abnormally hyperphosphorylated Tau is a key lesion of Alzheimer disease and other tauopathies, and its density in the brain directly correlates with dementia. The phosphorylation of Tau is regulated by protein phosphatase 2A, which in turn is regulated by inhibitor 2, I2(PP2A). In acidic conditions such as generated by brain ischemia and hypoxia, especially in association with hyperglycemia as in diabetes, I2(PP2A) is cleaved by asparaginyl endopeptidase at Asn-175 into the N-terminal fragment (I2NTF) and the C-terminal fragment (I2CTF). Both I2NTF and I2CTF are known to bind to the catalytic subunit of protein phosphatase 2A and inhibit its activity. Here we show that the level of activated asparaginyl endopeptidase is significantly increased, and this enzyme and I2(PP2A) translocate, respectively, from neuronal lysosomes and nucleus to the cytoplasm where they interact and are associated with hyperphosphorylated Tau in Alzheimer disease brain. Asparaginyl endopeptidase from Alzheimer disease brain could cleave GST-I2(PP2A), except when I2(PP2A) was mutated at the cleavage site Asn-175 to Gln. Finally, an induction of acidosis by treatment with kainic acid or pH 6.0 medium activated asparaginyl endopeptidase and consequently produced the cleavage of I2(PP2A), inhibition of protein phosphatase 2A, and hyperphosphorylation of Tau, and the knockdown of asparaginyl endopeptidase with siRNA abolished this pathway in SH-SY5Y cells. These findings suggest the involvement of brain acidosis in the etiopathogenesis of Alzheimer disease, and asparaginyl endopeptidase-I2(PP2A)-protein phosphatase 2A-Tau hyperphosphorylation pathway as a therapeutic target.

  1. Resveratrol Attenuates Formaldehyde Induced Hyperphosphorylation of Tau Protein and Cytotoxicity in N2a Cells

    PubMed Central

    He, Xiaping; Li, Zhenhui; Rizak, Joshua D.; Wu, Shihao; Wang, Zhengbo; He, Rongqiao; Su, Min; Qin, Dongdong; Wang, Jingkun; Hu, Xintian

    2017-01-01

    Recent studies have demonstrated that formaldehyde (FA)—induced neurotoxicity is important in the pathogenesis of Alzheimer's disease (AD). Elevated levels of FA have been associated with memory impairments and the main hallmarks of AD pathology, including β-amyloid plaques, tau protein hyperphosphorylation, and neuronal loss. Resveratrol (Res), as a polyphenol anti-oxidant, has been considered to have therapeutic potential for the treatment of AD. However, it has not been elucidated whether Res can exert its neuroprotective effects against FA-induced neuronal damages related to AD pathology. To answer this question, the effects of Res were investigated on Neuro-2a (N2a) cells prior to and after FA exposure. The experiments found that pre-treatment with Res significantly decreased FA-induced cytotoxicity, reduced cell apoptosis rates, and inhibited the hyperphosphorylation of tau protein at Thr181 in a dose-dependent manner. Further tests revealed that this effect was associated with the suppression of glycogen synthase kinase (GSK-3β) and calmodulin-dependent protein kinase II (CaMKII) activities, both of which are important kinases for tau protein hyperphosphorylation. In addition, Res was found to increase the activity of phosphoseryl/phosphothreonyl protein phosphatase-2A (PP2A). In summary, these findings provide evidence that Res protects N2a cells from FA-induced damages and suggests that inhibition of GSK-3β and CaMKII and the activation of PP2A by Res protect against the hyperphosphorylation and/or mediates the dephosphorylation of tau protein, respectively. These possible mechanisms underlying the neuroprotective effects of Res against FA-induced damages provide another perspective on AD treatment via inhibition of tau protein hyperhosphorylation. PMID:28197064

  2. Activation of Asparaginyl Endopeptidase Leads to Tau Hyperphosphorylation in Alzheimer Disease*

    PubMed Central

    Basurto-Islas, Gustavo; Grundke-Iqbal, Inge; Tung, Yunn Chyn; Liu, Fei; Iqbal, Khalid

    2013-01-01

    Neurofibrillary pathology of abnormally hyperphosphorylated Tau is a key lesion of Alzheimer disease and other tauopathies, and its density in the brain directly correlates with dementia. The phosphorylation of Tau is regulated by protein phosphatase 2A, which in turn is regulated by inhibitor 2, I2PP2A. In acidic conditions such as generated by brain ischemia and hypoxia, especially in association with hyperglycemia as in diabetes, I2PP2A is cleaved by asparaginyl endopeptidase at Asn-175 into the N-terminal fragment (I2NTF) and the C-terminal fragment (I2CTF). Both I2NTF and I2CTF are known to bind to the catalytic subunit of protein phosphatase 2A and inhibit its activity. Here we show that the level of activated asparaginyl endopeptidase is significantly increased, and this enzyme and I2PP2A translocate, respectively, from neuronal lysosomes and nucleus to the cytoplasm where they interact and are associated with hyperphosphorylated Tau in Alzheimer disease brain. Asparaginyl endopeptidase from Alzheimer disease brain could cleave GST-I2PP2A, except when I2PP2A was mutated at the cleavage site Asn-175 to Gln. Finally, an induction of acidosis by treatment with kainic acid or pH 6.0 medium activated asparaginyl endopeptidase and consequently produced the cleavage of I2PP2A, inhibition of protein phosphatase 2A, and hyperphosphorylation of Tau, and the knockdown of asparaginyl endopeptidase with siRNA abolished this pathway in SH-SY5Y cells. These findings suggest the involvement of brain acidosis in the etiopathogenesis of Alzheimer disease, and asparaginyl endopeptidase-I2PP2A-protein phosphatase 2A-Tau hyperphosphorylation pathway as a therapeutic target. PMID:23640887

  3. Intranasal insulin prevents anesthesia-induced hyperphosphorylation of tau in 3xTg-AD mice

    PubMed Central

    Chen, Yanxing; Run, Xiaoqin; Liang, Zhihou; Zhao, Yang; Dai, Chun-ling; Iqbal, Khalid; Liu, Fei; Gong, Cheng-Xin

    2014-01-01

    Background: It is well documented that elderly individuals are at increased risk of cognitive decline after anesthesia. General anesthesia is believed to be a risk factor for Alzheimer’s disease (AD). Recent studies suggest that anesthesia may increase the risk for cognitive decline and AD through promoting abnormal hyperphosphorylation of tau, which is crucial to neurodegeneration seen in AD. Methods: We treated 3xTg-AD mice, a commonly used transgenic mouse model of AD, with daily intranasal administration of insulin (1.75 U/day) for one week. The insulin- and control-treated mice were then anesthetized with single intraperitoneal injection of propofol (250 mg/kg body weight). Tau phosphorylation and tau protein kinases and phosphatases in the brains of mice 30 min and 2 h after propofol injection were then investigated by using Western blots and immunohistochemistry. Results: Propofol strongly promoted hyperphosphorylation of tau at several AD-related phosphorylation sites. Intranasal administration of insulin attenuated propofol-induced hyperphosphorylation of tau, promoted brain insulin signaling, and led to up-regulation of protein phosphatase 2A, a major tau phosphatase in the brain. Intranasal insulin also resulted in down-regulation of several tau protein kinases, including cyclin-dependent protein kinase 5, calcium/calmodulin-dependent protein kinase II, and c-Jun N-terminal kinase. Conclusion: Our results demonstrate that pretreatment with intranasal insulin prevents AD-like tau hyperphosphorylation. These findings provide the first evidence supporting that intranasal insulin administration might be used for the prevention of anesthesia-induced cognitive decline and increased risk for AD and dementia. PMID:24910612

  4. N-terminus of the protein kinase CLK1 induces SR protein hyperphosphorylation.

    PubMed

    Aubol, Brandon E; Plocinik, Ryan M; Keshwani, Malik M; McGlone, Maria L; Hagopian, Jonathan C; Ghosh, Gourisankar; Fu, Xiang-Dong; Adams, Joseph A

    2014-08-15

    SR proteins are essential splicing factors that are regulated through multisite phosphorylation of their RS (arginine/serine-rich) domains by two major families of protein kinases. The SRPKs (SR-specific protein kinases) efficiently phosphorylate the arginine/serine dipeptides in the RS domain using a conserved docking groove in the kinase domain. In contrast, CLKs (Cdc2-like kinases) lack a docking groove and phosphorylate both arginine/serine and serine-proline dipeptides, modifications that generate a hyperphosphorylated state important for unique SR protein-dependent splicing activities. All CLKs contain long flexible N-terminal extensions (140-300 residues) that resemble the RS domains present in their substrate SR proteins. We showed that the N-terminus in CLK1 contacts both the kinase domain and the RS domain of the SR protein SRSF1 (SR protein splicing factor 1). This interaction not only is essential for facilitating hyperphosphorylation, but also induces co-operative binding of SRSF1 to RNA. The N-terminus of CLK1 enhances the total phosphoryl contents of a panel of physiological substrates including SRSF1, SRSF2, SRSF5 and Tra2β1 (transformer 2β1) by 2-3-fold. These findings suggest that CLK1-dependent hyperphosphorylation is the result of a general mechanism in which the N-terminus acts as a bridge connecting the kinase domain and the RS domain of the SR protein.

  5. N-Terminus of the Protein Kinase CLK1 Induces SR Protein Hyper-Phosphorylation

    PubMed Central

    Aubol, Brandon E.; Plocinik, Ryan M.; Keshwani, Malik M.; McGlone, Maria L.; Hagopian, Jonathan C.; Ghosh, Gourisankar; Fu, Xiang-Dong; Adams, Joseph A.

    2016-01-01

    SR proteins are essential splicing factors that are regulated through multisite phosphorylation of their RS (arginine-serine-rich) domains by two major families of protein kinases. The SRPKs efficiently phosphorylate the arginine-serine dipeptides in the RS domain using a conserved docking groove in the kinase domain. In contrast, CLKs lack a docking groove and phosphorylate both arginine-serine and serine-proline dipeptides, modifications that generate a hyper-phosphorylated state important for unique SR protein-dependent splicing activities. All CLKs contain long, flexible N-terminal extensions (140-300 residues) that resemble the RS domains present in their substrate SR proteins. We showed that the N-terminus in CLK1 contacts both the kinase domain and the RS domain of the SR protein SRSF1. This interaction not only is essential for facilitating hyper-phosphorylation but also induces cooperative binding of SRSF1 to RNA. The N-terminus of CLK1 enhances the total phosphoryl contents of a panel of physiological substrates including SRSF1, SRSF2, SRSF5 and Tra2β1 by 2–3-fold. These findings suggest that CLK1-dependent hyper-phosphorylation is the result of a general mechanism in which the N-terminus acts as a bridge connecting the kinase domain and the RS domain of the SR protein. PMID:24869919

  6. Does neuroinflammation drive the relationship between tau hyperphosphorylation and dementia development following traumatic brain injury?

    PubMed

    Collins-Praino, Lyndsey E; Corrigan, Frances

    2017-02-01

    A history of traumatic brain injury (TBI) is linked to an increased risk for the later development of dementia. This encompasses a variety of neurodegenerative diseases including Alzheimer's Disease (AD) and chronic traumatic encephalopathy (CTE), with AD linked to history of moderate-severe TBI and CTE to a history of repeated concussion. Of note, both AD and CTE are characterized by the abnormal accumulation of hyperphosphorylated tau aggregates, which are thought to play an important role in the development of neurodegeneration. Hyperphosphorylation of tau leads to destabilization of microtubules, interrupting axonal transport, whilst tau aggregates are associated with synaptic dysfunction. The exact mechanisms via which TBI may promote the later tauopathy and its role in the later development of dementia are yet to be fully determined. Following TBI, it is proposed that axonal injury may provide the initial perturbation of tau, by promoting its dissociation from microtubules, facilitating its phosphorylation and aggregation. Altered tau dynamics may then be exacerbated by the chronic persistent inflammatory response that has been shown to persist for decades following the initial impact. Importantly, immune activation has been shown to play a role in accelerating disease progression in other tauopathies, with pro-inflammatory cytokines, like IL-1β, shown to activate kinases that promote tau hyperphosphorylation. Thus, targeting the inflammatory response in the sub-acute phase following TBI may represent a promising target to halt the alterations in tau dynamics that may precede overt neurodegeneration and later development of dementia.

  7. Choroidal detachment and ocular hypotony: CT evaluation

    SciTech Connect

    Mafee, M.F.; Peyman, G.A.

    1984-12-01

    The computed tomographic (CT) findings in 20 patients with hemorrhagic choroidal detachment, serous choroidal detachment and/or ocular hypotony are described. Hemorrhagic choroidal detachment appeared as an area of high attenuation that was usually localized, uniformly hyperdense, and not position-dependent. Serous choroidal detachment appeared as a convex, thick line of increased density within the vitreous cavity. Inflammatory choroidal detachment produces a diffuse intrauveal and suprachoroidal accumulation of high-density, position-dependent fluid, and uveoscleral thickening and enhancement, which in cross section resembles a ring. CT has proved valuable in localizing and differentiating serous or hemorrhagic choroidal detachment and uveoscleral infolding.

  8. Detached Breakwaters for Shore Protection.

    DTIC Science & Technology

    1986-01-01

    Presque Isle , Pennsylvania . . . 13 6Detached breakwater at Venice, California .. ............. 15& 7 Shoreline response to...at Presque Isle , Pennsylvania .. ...... 24 *13 Breakwater project at Colonial Beach , Virginia. ........... 27 14 Small recreational beach project at...in Pope and Rowen (1983). Presque Isle , Pennsylvania 23. At Presque Isle on Lake Erie , a segmented system of over 50 de- tached breakwaters is

  9. The mechanics of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2013-03-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular, and retinal pigment epithelium (RPE) pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed tissue within which e.g., the hydraulic conductivities of the retina or choroid increase, the RPE pumps fail, or the adhesion properties change. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. This work supported by the Army Research Office through grant 58386MA

  10. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M. P.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al.

  11. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M. P.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    The conditions of detached solidification under controlled pressure differential across the meniscus were investigated. Uncoated and graphite- or BN-coated silica and pBN crucibles were used. Detached and partly detached growth was achieved in pBN and BN-coated crucibles, respectively. The results of the experiments are discussed based on the theory of Duffar et al.

  12. Kinematic Fitting of Detached Vertices

    SciTech Connect

    Mattione, Paul

    2007-05-01

    The eg3 experiment at the Jefferson Lab CLAS detector aims to determine the existence of the $\\Xi_{5}$ pentaquarks and investigate the excited $\\Xi$ states. Specifically, the exotic $\\Xi_{5}^{--}$ pentaquark will be sought by first reconstructing the $\\Xi^{-}$ particle through its weak decays, $\\Xi^{-}\\to\\pi^{-}\\Lambda$ and $\\Lambda\\to\\pi^{-}$. A kinematic fitting routine was developed to reconstruct the detached vertices of these decays, where confidence level cuts on the fits are used to remove background events. Prior to fitting these decays, the exclusive reaction $\\gamma D\\rightarrow pp\\pi^{-}$ was studied in order to correct the track measurements and covariance matrices of the charged particles. The $\\Lambda\\rightarrow p\\pi^{-}$ and $\\Xi^{-}\\to\\pi^{-}\\Lambda$ decays were then investigated to demonstrate that the kinematic fitting routine reconstructs the decaying particles and their detached vertices correctly.

  13. Hyperphosphorylation of tau protein in the ipsilateral thalamus after focal cortical infarction in rats.

    PubMed

    Dong, Da-Wei; Zhang, Yu-Sheng; Yang, Wan-Yong; Wang-Qin, Run-Qi; Xu, An-Ding; Ruan, Yi-Wen

    2014-01-16

    Hyperphosphorylation of tau has been considered as an important risk factor for neurodegenerative diseases. It has been found also in the cortex after focal cerebral ischemia. The present study is aimed at investigating changes of tau protein expression in the ipsilateral thalamus remote from the primary ischemic lesion site after distal middle cerebral artery occlusion (MCAO). The number of neurons in the ventroposterior thalamic nucleus (VPN) was evaluated using Nissl staining and neuronal nuclei (NeuN) immunostaining. Total tau and phosphorylated tau at threonine 231 (p-T231-tau) and serine 199 (p-S199-tau) levels, respectively, in the thalamus were measured using immunostaining and immunoblotting. Moreover, apoptosis was detected with terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP-biotin nick-end labeling (TUNEL) assay. It was found that the numbers of intact neurons and NeuN(+) cells within the ipsilateral VPN were reduced significantly compared with the sham-operated group, but the levels of p-T231-tau and p-S199-tau in the ipsilateral thalamus were increased significantly in rats subjected to ischemia for 3 days, 7 days and 28 days. Furthermore, the number of TUNEL-positive cells was increased in the ipsilateral VPN at 7 days and 28 days after MCAO. Thus, hyperphosphorylated tau protein is observed in ipsilateral thalamus after focal cerebral infarction in this study. Our findings suggest that the expression of hyperphosphorylated tau protein induced by ischemia may be associated with the secondary thalamic damage after focal cortical infarction via an apoptotic pathway. © 2013 Published by Elsevier B.V.

  14. The Spleen Tyrosine Kinase (Syk) Regulates Alzheimer Amyloid-β Production and Tau Hyperphosphorylation*

    PubMed Central

    Paris, Daniel; Ait-Ghezala, Ghania; Bachmeier, Corbin; Laco, Gary; Beaulieu-Abdelahad, David; Lin, Yong; Jin, Chao; Crawford, Fiona; Mullan, Michael

    2014-01-01

    We have previously shown that the L-type calcium channel (LCC) antagonist nilvadipine reduces brain amyloid-β (Aβ) accumulation by affecting both Aβ production and Aβ clearance across the blood-brain barrier (BBB). Nilvadipine consists of a mixture of two enantiomers, (+)-nilvadipine and (−)-nilvadipine, in equal proportion. (+)-Nilvadipine is the active enantiomer responsible for the inhibition of LCC, whereas (−)-nilvadipine is considered inactive. Both nilvadipine enantiomers inhibit Aβ production and improve the clearance of Aβ across the BBB showing that these effects are not related to LCC inhibition. In addition, treatment of P301S mutant human Tau transgenic mice (transgenic Tau P301S) with (−)-nilvadipine reduces Tau hyperphosphorylation at several Alzheimer disease (AD) pertinent epitopes. A search for the mechanism of action of (−)-nilvadipine revealed that this compound inhibits the spleen tyrosine kinase (Syk). We further validated Syk as a target-regulating Aβ by showing that pharmacological inhibition of Syk or down-regulation of Syk expression reduces Aβ production and increases the clearance of Aβ across the BBB mimicking (−)-nilvadipine effects. Moreover, treatment of transgenic mice overexpressing Aβ and transgenic Tau P301S mice with a selective Syk inhibitor respectively decreased brain Aβ accumulation and Tau hyperphosphorylation at multiple AD relevant epitopes. We show that Syk inhibition induces an increased phosphorylation of the inhibitory Ser-9 residue of glycogen synthase kinase-3β, a primary Tau kinase involved in Tau phosphorylation, by activating protein kinase A, providing a mechanism explaining the reduction of Tau phosphorylation at GSK3β-dependent epitopes following Syk inhibition. Altogether our data highlight Syk as a promising target for preventing both Aβ accumulation and Tau hyperphosphorylation in AD. PMID:25331948

  15. Region-Specific Vulnerability to Oxidative Stress, Neuroinflammation, and Tau Hyperphosphorylation in Experimental Diabetes Mellitus Mice.

    PubMed

    Elahi, Montasir; Hasan, Zafrul; Motoi, Yumiko; Matsumoto, Shin-Ei; Ishiguro, Koichi; Hattori, Nobutaka

    2016-01-01

    Recent epidemiological evidence suggests that diabetes mellitus (DM) is a risk factor for Alzheimer's disease (AD). One of the pathological hallmarks of AD is hyperphosphorylated tau protein, which forms neurofibrillary tangles. Oxidative stress and the activation of inflammatory pathways are features that are associated with both DM and AD. However, the brain region specificity of AD-related neurodegeneration, which mainly occurs in the hippocampus while the cerebellum is relatively unaffected, has not yet been clarified. Therefore, we used experimental DM mice (caused by an intraperitoneal injection of streptozotocin [STZ]) to determine whether these neurodegeneration-associated mechanisms were associated with region-specific selective vulnerability or tau phosphorylation. The hippocampus, midbrain, and cerebellum of aged (14 to 18 months old) non-transgenic (NTg) and transgenic mice overexpressing wild-type human tau (Tg601 mice) were evaluated after a treatment with STZ. The STZ injection increased reactive oxygen species, lipid peroxidation markers such as 4-hydroxynonenal and malondialdehyde in the hippocampus, but not in the midbrain or cerebellum. The STZ treatment also increased the number of Iba-1-positive and CD68-positive microglial cells, astrocytes, and IL-1β, IL-6, IL-10, and IL-18 levels in the hippocampus, but not in the midbrain or cerebellum. Tau hyperphosphorylation was also enhanced in the hippocampus, but not in the midbrain or cerebellum. When the effects of STZ were compared between Tg601 and NTg mice, microglial proliferation and elevations in IL-6 and phosphorylated tau were higher in Tg601 mice. These results suggest that neuroinflammation and oxidative stress in STZ-treated mice are associated with tau hyperphosphorylation, which may contribute to selective neurodegeneration in human AD.

  16. Hyperphosphorylated Tau in an α-synuclein-overexpressing transgenic model of Parkinson's disease.

    PubMed

    Haggerty, Thomas; Credle, Joel; Rodriguez, Olga; Wills, Jonathan; Oaks, Adam W; Masliah, Eliezer; Sidhu, Anita

    2011-05-01

    Although clinically distinct diseases, tauopathies and synucleinopathies share a common genesis and mechanisms, leading to overlapping degenerative changes within neurons. In human postmortem striatum of Parkinson's disease (PD) and PD with dementia, we have recently described elevated levels of tauopathy, indexed as increased hyperphosphorylated Tau (p-Tau). Here we assessed tauopathy in striatum of a transgenic animal model of PD, overexpressing human α-synuclein under the platelet-derived growth factor promoter. At 11 months of age, large and progressive increases in p-Tau in transgenic mice, hyperphosphorylated at sites reminiscent of Alzheimer's disease, were noted, along with elevated levels of α-synuclein and glycogen synthase kinase 3β phosphorylated at Tyr216 (p-GSK-3β), a major kinase involved in the hyperphosphorylation of Tau. Differential Triton X-100 extraction of striata showed the presence of aggregated α-synuclein in the transgenic mice, along with p-Tau and p-GSK-3β, which was also confirmed through immunohistochemistry. After p-Tau formation, both Tau and microtubule-associated protein 1 (MAP1) dissociated from the cytoskeleton, consistent with the diminished ability of these cytoskeleton-binding proteins to bind microtubules. Increases in free tubulin and actin were also noted, indicative of cytoskeleton remodeling and destabilization. In vivo magnetic resonance imaging of the transgenic animals showed a reduction in brain volume of transgenic mice, indicating substantial atrophy. From immunohistochemical studies, α-synuclein, p-Tau and p-GSK-3β were found to be overexpressed and co-localized in large inclusion bodies, reminiscent of Lewy bodies. The elevated state of tauopathy seen in these platelet-derived growth factor-α-synuclein mice provides further confirmation that PD may be a tauopathic disease.

  17. Alzheimer-related decrease in CYFIP2 links amyloid production to tau hyperphosphorylation and memory loss

    PubMed Central

    Tiwari, Sachin Suresh; Mizuno, Keiko; Ghosh, Anshua; Aziz, Wajeeha; Troakes, Claire; Daoud, Jason; Golash, Vidushi; Noble, Wendy; Hortobágyi, Tibor

    2016-01-01

    Characteristic features of Alzheimer’s disease are memory loss, plaques resulting from abnormal processing of amyloid precursor protein (APP), and presence of neurofibrillary tangles and dystrophic neurites containing hyperphosphorylated tau. Currently, it is not known what links these abnormalities together. Cytoplasmic FMR1 interacting protein 2 (CYFIP2) has been suggested to regulate mRNA translation at synapses and this may include local synthesis of APP and alpha-calcium/calmodulin-dependent kinase II, a kinase that can phosphorylate tau. Further, CYFIP2 is part of the Wiskott-Aldrich syndrome protein-family verprolin-homologous protein complex, which has been implicated in actin polymerization at synapses, a process thought to be required for memory formation. Our previous studies on p25 dysregulation put forward the hypothesis that CYFIP2 expression is reduced in Alzheimer’s disease and that this contributes to memory impairment, abnormal APP processing and tau hyperphosphorylation. Here, we tested this hypothesis. First, in post-mortem tissue CYFIP2 expression was reduced by ∼50% in severe Alzheimer’s hippocampus and superior temporal gyrus when normalized to expression of a neuronal or synaptic marker protein. Interestingly, there was also a trend for decreased expression in mild Alzheimer’s disease hippocampus. Second, CYFIP2 expression was reduced in old but not in young Tg2576 mice, a model of familial Alzheimer’s disease. Finally, we tested the direct impact of reduced CYFIP2 expression in heterozygous null mutant mice. We found that in hippocampus this reduced expression causes an increase in APP and β-site amyloid precursor protein cleaving enzyme 1 (BACE1) protein, but not mRNA expression, and elevates production of amyloid-β42. Reduced CYFIP2 expression also increases alpha-calcium/calmodulin-dependent kinase II protein expression, and this is associated with hyperphosphorylation of tau at serine-214. The reduced expression also

  18. Evidence of Tau Hyperphosphorylation and Dystrophic Microglia in the Common Marmoset

    PubMed Central

    Rodriguez-Callejas, Juan D.; Fuchs, Eberhard; Perez-Cruz, Claudia

    2016-01-01

    Common marmosets (Callithrix jacchus) have recently gained popularity in biomedical research as models of aging research. Basically, they confer advantages from other non-human primates due to their shorter lifespan with onset of appearance of aging at 8 years. Old marmosets present some markers linked to neurodegeneration in the brain such as amyloid beta (Aβ)1-42 and Aβ1-40. However, there are no studies exploring other cellular markers associated with neurodegenerative diseases in this non-human primate. Using immunohistochemistry, we analyzed brains of male adolescent, adult, old, and aged marmosets. We observed accumulation of Aβ1-40 and Aβ1-42 in the cortex of aged subjects. Tau hyperphosphorylation was already detected in the brain of adolescent animals and increased with aging in a more fibrillary form. Microglia activation was also observed in the aging process, while a dystrophic phenotype accumulates in aged subjects. Interestingly, dystrophic microglia contained hyperphosphorylated tau, but active microglia did not. These results support previous findings regarding microglia dysfunctionality in aging and neurodegenerative diseases as Alzheimer’s disease. Further studies should explore the functional consequences of these findings to position this non-human primate as animal model of aging and neurodegeneration. PMID:28066237

  19. Cornel Iridoid Glycoside Attenuates Tau Hyperphosphorylation by Inhibition of PP2A Demethylation.

    PubMed

    Yang, Cui-Cui; Kuai, Xue-Xian; Li, Ya-Li; Zhang, Li; Yu, Jian-Chun; Li, Lin; Zhang, Lan

    2013-01-01

    Aim. The aim of the present study was to investigate the effect of cornel iridoid glycoside (CIG) on tau hyperphosphorylation induced by wortmannin (WT) and GF-109203X (GFX) and the underlying mechanisms. Methods. Human neuroblastoma SK-N-SH cells were preincubated with CIG (50, 100, and 200 µg/ml, resp.) for 24 h and then exposed to 10 µM WT and 10 µM GFX for 3 h after washing out CIG. Immunohistochemistry was used to observe the microtubular cytoskeleton of the cultured cells. Western blotting was used to measure the phosphorylation level of tau protein, glycogen synthase kinase 3 β (GSK-3 β ), and protein phosphatase 2A (PP2A). The activity of PP2A was detected by a biochemical assay. Results. Preincubation of CIG significantly attenuated the WT/GFX-induced tau hyperphosphorylation at the sites of Thr205, Thr212, Ser214, Thr217, Ser396, and PHF-1 and improved the damage of morphology and microtubular cytoskeleton of the cells. CIG did not prevent the decrease in p-AKT-ser473 and p-GSK-3 β -ser9 induced by WT/GFX. However, CIG significantly elevated the activity of PP2A by reducing the demethylation of PP2A catalytic subunit (PP2Ac) at Leu309 and the ratio of PME-1/LCMT in the WT/GFX-treated cells. The results suggest that CIG may be beneficial to the treatment of AD.

  20. Cornel Iridoid Glycoside Attenuates Tau Hyperphosphorylation by Inhibition of PP2A Demethylation

    PubMed Central

    Yang, Cui-cui; Kuai, Xue-xian; Li, Ya-li; Zhang, Li; Yu, Jian-chun; Li, Lin; Zhang, Lan

    2013-01-01

    Aim. The aim of the present study was to investigate the effect of cornel iridoid glycoside (CIG) on tau hyperphosphorylation induced by wortmannin (WT) and GF-109203X (GFX) and the underlying mechanisms. Methods. Human neuroblastoma SK-N-SH cells were preincubated with CIG (50, 100, and 200 µg/ml, resp.) for 24 h and then exposed to 10 µM WT and 10 µM GFX for 3 h after washing out CIG. Immunohistochemistry was used to observe the microtubular cytoskeleton of the cultured cells. Western blotting was used to measure the phosphorylation level of tau protein, glycogen synthase kinase 3β (GSK-3β), and protein phosphatase 2A (PP2A). The activity of PP2A was detected by a biochemical assay. Results. Preincubation of CIG significantly attenuated the WT/GFX-induced tau hyperphosphorylation at the sites of Thr205, Thr212, Ser214, Thr217, Ser396, and PHF-1 and improved the damage of morphology and microtubular cytoskeleton of the cells. CIG did not prevent the decrease in p-AKT-ser473 and p-GSK-3β-ser9 induced by WT/GFX. However, CIG significantly elevated the activity of PP2A by reducing the demethylation of PP2A catalytic subunit (PP2Ac) at Leu309 and the ratio of PME-1/LCMT in the WT/GFX-treated cells. The results suggest that CIG may be beneficial to the treatment of AD. PMID:24454482

  1. IGFBP-1 hyperphosphorylation in response to leucine deprivation is mediated by the AAR pathway.

    PubMed

    Malkani, Niyati; Jansson, Thomas; Gupta, Madhulika B

    2015-09-05

    Insulin-like growth factor-1 (IGF-I) is the key regulator of fetal growth. IGF-I bioavailability is markedly diminished by IGF binding protein-1 (IGFBP-1) phosphorylation. Leucine deprivation strongly induces IGFBP-1 hyperphosphorylation, and plays an important role in fetal growth restriction (FGR). FGR is characterized by decreased amino acid availability, which activates the amino acid response (AAR) and inhibits the mechanistic target of rapamycin (mTOR) pathway. We investigated the role of AAR and mTOR in mediating IGFBP-1 secretion and phosphorylation in HepG2 cells in leucine deprivation. mTOR inhibition (rapamycin or raptor + rictor siRNA), or activation (DEPTOR siRNA) demonstrated a role of mTOR in leucine deprivation-induced IGFBP-1 secretion but not phosphorylation. When the AAR was blocked (U0126, or ERK/GCN2 siRNA), both IGFBP-1 secretion and hyperphosphorylation (pSer101/pSer119/pSer169) due to leucine deprivation were prevented. CK2 inhibition by TBB also attenuated IGFBP-1 phosphorylation in leucine deprivation. These results suggest that the AAR and mTOR independently regulate IGFBP-1 secretion and phosphorylation in response to decreased amino acid availability.

  2. Tributyltin induces disruption of microfilament in HL7702 cells via MAPK-mediated hyperphosphorylation of VASP.

    PubMed

    Tu, Wei-Wei; Ji, Lin-Dan; Qian, Hai-Xia; Zhou, Mi; Zhao, Jin-Shun; Xu, Jin

    2016-11-01

    Tributyltin (TBT) has been widely used for various industrial purposes, and it has toxic effects on multiple organs and tissues. Previous studies have found that TBT could induce cytoskeletal disruption, especially of the actin filaments. However, the underlying mechanisms remain unclear. The aim of the present study was to determine whether TBT could induce microfilament disruption using HL7702 cells and then to assess for the total levels of various microfilament-associated proteins; finally, the involvement of the MAPK pathway was investigated. The results showed that after TBT treatment, F-actin began to depolymerize and lost its characteristic filamentous structure. The protein levels of Ezrin and Cofilin remained unchanged, the actin-related protein (ARP) 2/3 levels decreased slightly, and the vasodilator-stimulated phosphoprotein (VASP) decreased dramatically. However, the phosphorylation levels of VASP increased 2.5-fold, and the ratio of phosphorylated-VASP/unphosphorylated-VASP increased 31-fold. The mitogen-activated protein kinases (MAPKs) ERK and JNK were discovered to be activated. Inhibition of ERK and JNK not only largely diminished the TBT-induced hyperphosphorylation of VASP but also recovered the cellular morphology and rescued the cells from death. In summary, this study demonstrates that TBT-induced disruption of actin filaments is caused by the hyperphosphorylation of VASP through MAPK pathways. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1530-1538, 2016. © 2015 Wiley Periodicals, Inc.

  3. Fluorine negative ion detachment kinetics

    NASA Technical Reports Server (NTRS)

    Burke, R. R.; Miller, W. J.; Gould, R. K.

    1971-01-01

    A study of the rate of F(-) detachment by O and H atoms via the reactions F(-) + O yields FO + e and F(-) + H yields FH+ e was undertaken using a drift tube to produce F(-) ions at various drift velocities and therefore different ion temperatures. Preliminary mobility measurements of F(-) ions in Ar were made, indicating that ion temperatures in the 300 K to 5000 K range could be achieved; however due to numerous difficulties experienced in obtaining a reliable F(-) ion source, the study could not be completed.

  4. PIC Simulation of plasma detachment

    NASA Astrophysics Data System (ADS)

    Ishiguro, Seiji; Pianpanit, Theerasarn; Hasegawa, Hiroki; Kanno, Ryutaro

    2014-10-01

    The detached plasma, which is caused by gas puffing, has been proposed and it is the most promising way to reduce the heat load to the divertor plate of fusion oriented devices. Dynamical and kinetic behavior of the detached plasma is unresolved. So we are developing particle-in-cell simulation model with atomic processes such as line radiation, ionization, charge-exchange collision and recombination. As a first step, we have performed PIC simulation with Monte Carlo collisions, where spatial and velocity space distributions of charged particles, self-consistent electric field, and atomic processes such as ionization and charge exchange are included. Temperature decrease and density increase in front of the target is observed and electric potential structure along the axis is created. This work is performed with the support and under the auspices of NIFS Collaboration Research programs (NIFS14KNXN279 and 8 NIFS13KNSS038) and the Research Cooperation Program on Hierarchy and Holism in Natural Sciences at the NINS.

  5. Involvement of Hepatitis C Virus NS5A Hyperphosphorylation Mediated by Casein Kinase I-α in Infectious Virus Production

    PubMed Central

    Masaki, Takahiro; Matsunaga, Satoko; Takahashi, Hirotaka; Nakashima, Kenji; Kimura, Yayoi; Ito, Masahiko; Matsuda, Mami; Murayama, Asako; Kato, Takanobu; Hirano, Hisashi; Endo, Yaeta; Lemon, Stanley M.; Wakita, Takaji; Sawasaki, Tatsuya

    2014-01-01

    ABSTRACT Nonstructural protein 5A (NS5A) of hepatitis C virus (HCV) possesses multiple functions in the viral life cycle. NS5A is a phosphoprotein that exists in hyperphosphorylated and basally phosphorylated forms. Although the phosphorylation status of NS5A is considered to have a significant impact on its function, the mechanistic details regulating NS5A phosphorylation, as well as its exact roles in the HCV life cycle, are still poorly understood. In this study, we screened 404 human protein kinases via in vitro binding and phosphorylation assays, followed by RNA interference-mediated gene silencing in an HCV cell culture system. Casein kinase I-α (CKI-α) was identified as an NS5A-associated kinase involved in NS5A hyperphosphorylation and infectious virus production. Subcellular fractionation and immunofluorescence confocal microscopy analyses showed that CKI-α-mediated hyperphosphorylation of NS5A contributes to the recruitment of NS5A to low-density membrane structures around lipid droplets (LDs) and facilitates its interaction with core protein and the viral assembly. Phospho-proteomic analysis of NS5A with or without CKI-α depletion identified peptide fragments that corresponded to the region located within the low-complexity sequence I, which is important for CKI-α-mediated NS5A hyperphosphorylation. This region contains eight serine residues that are highly conserved among HCV isolates, and subsequent mutagenesis analysis demonstrated that serine residues at amino acids 225 and 232 in NS5A (genotype 2a) may be involved in NS5A hyperphosphorylation and hyperphosphorylation-dependent regulation of virion production. These findings provide insight concerning the functional role of NS5A phosphorylation as a regulatory switch that modulates its multiple functions in the HCV life cycle. IMPORTANCE Mechanisms regulating NS5A phosphorylation and its exact function in the HCV life cycle have not been clearly defined. By using a high-throughput screening

  6. Retinal detachment following cataract surgery with capsulorhexis.

    PubMed Central

    Kelley, J S; Doxanas, M T

    1995-01-01

    PURPOSE: To estimate the incidence of retinal detachment after cataract surgery with capsulorhexis. METHODS: A consecutive series of 2,150 cataract operations were followed for incidence of retinal detachment. A series of 1,000 patients from this group were analyzed for high risk factors: myopia, age, sex, operative complications and capsulotomy. RESULTS: With minimum one year follow up in 90% of patients the incidence of retinal detachment was 0.25% (5 cases). CONCLUSION: The true incidence of retinal detachment after cataract surgery remains elusive. There is probably a trend toward lower incidence compared to previous reports. PMID:8719688

  7. Roller coaster-associated retinal detachments.

    PubMed

    Shaikh, Saad

    2011-01-01

    The purpose of this study was to report two cases of rhegmatogenous retinal detachment noted immediately after roller coaster riding in an at-risk population. In separate incidents, a 35-year-old woman and a 45-year-old woman, both significantly myopic, presented with visual symptoms after riding roller coasters. Both patients were found to have acute rhegmatogenous retinal detachments associated with myopic degenerative changes. The pathology supported an acute, traumatic etiology for the detachments. Roller coaster riding should be considered an adjunct risk factor for retinal detachment in predisposed patients.

  8. Dynamic stability of detached solidification

    NASA Astrophysics Data System (ADS)

    Mazuruk, K.; Volz, M. P.

    2016-06-01

    A dynamic stability analysis model is developed for meniscus-defined crystal growth processes. The Young-Laplace equation is used to analyze the response of a growing crystal to perturbations to its radius and a thermal transport model is used to analyze the effect of perturbations on the evolution of the crystal-melt interface. A linearized differential equation is used to analyze radius perturbations but a linear integro-differential equation is required for the height perturbations. The stability model is applied to detached solidification under zero-gravity and terrestrial conditions. A numerical analysis is supplemented with an approximate analytical analysis, valid in the limit of small Bond numbers. For terrestrial conditions, a singularity is found to exist in the capillary stability coefficients where, at a critical value of the pressure differential across the meniscus, there is a transition from stability to instability. For the zero-gravity condition, exact formulas for the capillary stability coefficients are derived.

  9. Truncation and activation of GSK-3β by calpain I: a molecular mechanism links to tau hyperphosphorylation in Alzheimer's disease

    PubMed Central

    Jin, Nana; Yin, Xiaomin; Yu, Dian; Cao, Maohong; Gong, Cheng-Xin; Iqbal, Khalid; Ding, Fei; Gu, Xiaosong; Liu, Fei

    2015-01-01

    Abnormal hyperphosphorylation of tau is pivotally involved in the pathogenesis of Alzheimer's disease (AD) and related tauopathies. Glycogen synthase kinase 3β (GSK-3β) is a primary tau kinase that is most implicated in tau pathology in AD. However, the exact molecular nature of GSK-3β involved in AD is unclear. In the present study, we found that GSK-3β was truncated at C-terminus and correlated with over-activation of calpain I in AD brain. Truncation of GSK-3β was positively correlated with tau hyperphosphorylation, tangles score and Braak stage in human brain. Calpain I proteolyzed GSK-3β in vitro at C-terminus, leading to an increase of its kinase activity, but keeping its characteristic to preferentially phosphorylate the protein kinase A-primed tau. Excitotoxicity induced by kainic acid (KA) caused GSK-3β truncation at C-terminus and hyperphosphorylation of tau in mouse brain. Inhibition of calpain prevented the KA-induced changes. These findings suggest that truncation of GSK-3β by Ca2+/calpain I markedly increases its activity and involvement of this mechanism probably is responsible for up-regulation of GSK-3β and consequent abnormal hyperphosphorylation of tau and neurofibrillary degeneration in AD. PMID:25641096

  10. Loss of Prohibitin Membrane Scaffolds Impairs Mitochondrial Architecture and Leads to Tau Hyperphosphorylation and Neurodegeneration

    PubMed Central

    Merkwirth, Carsten; Morbin, Michela; Brönneke, Hella S.; Jordan, Sabine D.; Rugarli, Elena I.; Langer, Thomas

    2012-01-01

    Fusion and fission of mitochondria maintain the functional integrity of mitochondria and protect against neurodegeneration, but how mitochondrial dysfunctions trigger neuronal loss remains ill-defined. Prohibitins form large ring complexes in the inner membrane that are composed of PHB1 and PHB2 subunits and are thought to function as membrane scaffolds. In Caenorhabditis elegans, prohibitin genes affect aging by moderating fat metabolism and energy production. Knockdown experiments in mammalian cells link the function of prohibitins to membrane fusion, as they were found to stabilize the dynamin-like GTPase OPA1 (optic atrophy 1), which mediates mitochondrial inner membrane fusion and cristae morphogenesis. Mutations in OPA1 are associated with dominant optic atrophy characterized by the progressive loss of retinal ganglion cells, highlighting the importance of OPA1 function in neurons. Here, we show that neuron-specific inactivation of Phb2 in the mouse forebrain causes extensive neurodegeneration associated with behavioral impairments and cognitive deficiencies. We observe early onset tau hyperphosphorylation and filament formation in the hippocampus, demonstrating a direct link between mitochondrial defects and tau pathology. Loss of PHB2 impairs the stability of OPA1, affects mitochondrial ultrastructure, and induces the perinuclear clustering of mitochondria in hippocampal neurons. A destabilization of the mitochondrial genome and respiratory deficiencies manifest in aged neurons only, while the appearance of mitochondrial morphology defects correlates with tau hyperphosphorylation in the absence of PHB2. These results establish an essential role of prohibitin complexes for neuronal survival in vivo and demonstrate that OPA1 stability, mitochondrial fusion, and the maintenance of the mitochondrial genome in neurons depend on these scaffolding proteins. Moreover, our findings establish prohibitin-deficient mice as a novel genetic model for tau pathologies

  11. Experimental results from detached plasmas in TFTR

    SciTech Connect

    Strachan, J.D.; Boody, F.P.; Bush, C.E.; Cohen, S.A.; Grek, B.; Grisham, L.; Jobes, F.C.; Johnson, D.W.; Mansfield, D.K.; Medley, S.S.

    1986-10-01

    Detached plasmas are formed in TFTR which have the principal property of the boundary to the high temperature plasma core being defined by a radiating layer. This paper documents the properties of TFTR ohmic-detached plasmas with a range of plasma densities at two different plasma currents.

  12. Tau-Induced Ca(2+)/Calmodulin-Dependent Protein Kinase-IV Activation Aggravates Nuclear Tau Hyperphosphorylation.

    PubMed

    Wei, Yu-Ping; Ye, Jin-Wang; Wang, Xiong; Zhu, Li-Ping; Hu, Qing-Hua; Wang, Qun; Ke, Dan; Tian, Qing; Wang, Jian-Zhi

    2017-06-23

    Hyperphosphorylated tau is the major protein component of neurofibrillary tangles in the brains of patients with Alzheimer's disease (AD). However, the mechanism underlying tau hyperphosphorylation is not fully understood. Here, we demonstrated that exogenously expressed wild-type human tau40 was detectable in the phosphorylated form at multiple AD-associated sites in cytoplasmic and nuclear fractions from HEK293 cells. Among these sites, tau phosphorylated at Thr205 and Ser214 was almost exclusively found in the nuclear fraction at the conditions used in the present study. With the intracellular tau accumulation, the Ca(2+) concentration was significantly increased in both cytoplasmic and nuclear fractions. Further studies using site-specific mutagenesis and pharmacological treatment demonstrated that phosphorylation of tau at Thr205 increased nuclear Ca(2+) concentration with a simultaneous increase in the phosphorylation of Ca(2+)/calmodulin-dependent protein kinase IV (CaMKIV) at Ser196. On the other hand, phosphorylation of tau at Ser214 did not significantly change the nuclear Ca(2+)/CaMKIV signaling. Finally, expressing calmodulin-binding protein-4 that disrupts formation of the Ca(2+)/calmodulin complex abolished the okadaic acid-induced tau hyperphosphorylation in the nuclear fraction. We conclude that the intracellular accumulation of phosphorylated tau, as detected in the brains of AD patients, can trigger nuclear Ca(2+)/CaMKIV signaling, which in turn aggravates tau hyperphosphorylation. Our findings provide new insights for tauopathies: hyperphosphorylation of intracellular tau and an increased Ca(2+) concentration may induce a self-perpetuating harmful loop to promote neurodegeneration.

  13. Chronic noise exposure causes persistence of tau hyperphosphorylation and formation of NFT tau in the rat hippocampus and prefrontal cortex.

    PubMed

    Cui, Bo; Zhu, Lixing; She, Xiaojun; Wu, Mingquan; Ma, Qiang; Wang, Tianhui; Zhang, Na; Xu, Chuanxiang; Chen, Xuewei; An, Gaihong; Liu, Hongtao

    2012-12-01

    The non-auditory effects of noise exposure on the central nervous system have been established both epidemiologically and experimentally. Chronic noise exposure (CNE) has been associated with tau hyperphosphorylation and Alzheimer's disease (AD)-like pathological changes. However, experimental evidence for these associations remains limited. The aim of the current study was to explore the effects of CNE [100 dB sound pressure level (SPL) white noise, 4 h/d×14 d] on tau phosphorylation in the rat hippocampus and the prefrontal cortex. Forty-eight male Wistar rats were randomly assigned to two groups: a noise-exposed group and a control group. The levels of radioimmunoprecipitation assay (RIPA)-soluble and RIPA-insoluble phosphorylated tau at Ser202, Ser396, Ser404, and Ser422 in the hippocampus and the prefrontal cortex were measured at different time points (days 0, 3, 7, and 14) after the end of the last noise exposure. Exposure to white noise for 14 consecutive days significantly increased the levels of tau phosphorylation at Ser202, Ser396, Ser404, and Ser422, the sites typically phosphorylated in AD brains, in the hippocampus and the prefrontal cortex. Tau hyperphosphorylation persisted for 7 to 14 d after the cessation of noise exposure. These alterations were also concomitant with the generation of pathological neurofibrillary tangle (NFT) tau 3, 7 and 14 d after the end of the stimulus. Furthermore, lasting increases in proteins involved in hyperphosphorylation, namely glycogen synthase kinase 3β (GSK3β) and protein phosphatase 2A (PP2A), were found to occur in close correspondence with increase in tau hyperphosphorylation. The results of this study show that CNE leads to long-lasting increases in non-NFT hyperphosphorylated tau and delayed formation of misfolded NFT tau in the hippocampus and the prefrontal cortex. Our results also provide evidence for the involvement of GSK3β and PP2A in these processes.

  14. Retinal detachment after open globe injury

    PubMed Central

    Stryjewski, Tomasz P.; Andreoli, Christopher M.; Eliott, Dean

    2013-01-01

    Purpose To characterize the development of retinal detachment after open globe trauma. Design Case-control study Participants 892 patients comprising 893 open globe injuries, of which 255 were ultimately diagnosed with retinal detachment, with the remaining eyes serving as controls. Methods Retrospective chart review of open globe injuries presenting to the Massachusetts Eye and Ear Infirmary between 1999 and 2011. Kaplan-Meier analysis was used to estimate time to detachment and multivariable logistic regression was used to define clinical factors associated with retinal detachment after open globe injury. Main Outcome Measures Demographic and clinical characteristics at the time of presentation after open globe injury, date of retinal detachment diagnosis, and last date of follow-up. Results Primary repair of the open globe was typically undertaken within hours of presentation. 255 eyes were ultimately diagnosed with retinal detachment after open globe trauma, yielding an incidence of 29% (95% confidence interval: 26%-32%). For eyes that developed retinal detachment, 27% (69/255) detached within 24 hours of primary open globe repair, 47% (119/255) detached within one week, 72% (183/255) within one month. Multivariable regression analysis revealed presence of vitreous hemorrhage (odds ratio: 7.29, p<0.001), higher zone of injury (odds ratio: 2.51 per integer increase in zone number, odds ratio: 1.00-6.30, p<0.001), and poorer Logarithm of the Minimum Angle of Resolution visual acuity at the time of presentation after open globe injury (odds ratio: 2.41 per integer increase in Logarithm of the Minimum Angle of Resolution visual acuity, odds ratio: 1.00-81.30, p<0.001) to be associated with retinal detachment. A screening tool, named herein the Retinal Detachment after Open Globe Injury (RD-OGI) score, was created. Conclusions Retinal detachment is common after open globe trauma, though often not appearing until days to weeks after the initial traumatic event

  15. Dynamics of mussel plaque detachment.

    PubMed

    Desmond, Kenneth W; Zacchia, Nicholas A; Waite, J Herbert; Valentine, Megan T

    2015-09-14

    Mussels are well known for their ability to generate and maintain strong, long-lasting adhesive bonds under hostile conditions. Many prior studies attribute their adhesive strength to the strong chemical interactions between the holdfast and substrate. While chemical interactions are certainly important, adhesive performance is also determined by contact geometry, and understanding the coupling between chemical interactions and the plaque shape and mechanical properties is essential in deploying bioinspired strategies when engineering improved adhesives. To investigate how the shape and mechanical properties of the mussel's plaque contribute to its adhesive performance, we use a custom built load frame capable of fully characterizing the dynamics of the detachment. With this, we can pull on samples along any orientation, while at the same time measuring the resulting force and imaging the bulk deformations of the plaque as well as the holdfast-substrate interface where debonding occurs. We find that the force-induced yielding of the mussel plaque improves the bond strength by two orders of magnitude and that the holdfast shape improves bond strength by an additional order of magnitude as compared to other simple geometries. These results demonstrate that optimizing the contact geometry can play as important a role on adhesive performance as optimizing the chemical interactions as observed in other organisms and model systems.

  16. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Vujisic, L.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years, especially under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 micrometers, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5 mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 micrometers. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  17. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Motakef, S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years especially, under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 microns, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 microns. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  18. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Motakef, S.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years especially, under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 microns, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 microns. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  19. Stability of Detached Grown Germanium Single Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Vujisic, L.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    Detachment of the melt meniscus from the crucible during semiconductor Bridgman growth experiments has been observed in recent years, especially under microgravity experiments. Under earth conditions, the hydrostatic pressure counteracts the mechanism, whereby it is more difficult to achieve detached Bridgman growth. Attempts to get stable detached growth under terrestrial conditions have been discussed in the literature and have been the subject of recent experiments in our own group. The advantage of crystals grown without wall contact is obvious: In general, they possess a higher crystal quality than conventional Bridgman grown crystals with wall contact. However, due to the interaction of different parameters such as the wetting behavior of the melt with the crucible, and the dependence of the growth angle with the shape of the melt meniscus, the mechanism leading to detachment is very complicated and not completely understood. We have grown several doped and undoped Germanium crystals with the detached Bridgman and the normal Bridgman growth technique. Pyrolytic boron nitride containers were used for all growth experiments. In the detached grown crystals the typical gap thickness between the pBN crucible and the crystal is in the range of 10 to 100 micrometers, which was determined by performing profilometer measurements. Etch pit density measurements were also performed and a comparison between detached and attached grown crystals will be given. An interesting feature was detected on the surface of a detached grown crystal. Strong surface striations with an average axial distance of 0.5 mm were observed around the whole circumference. The maximum fluctuation of the gap thickness is in the range of 5-10 micrometers. These variations of the detached gap along the crystal axis can be explained by a kind of stiction of the melt/crucible interface and thus by a variation of the meniscus shape. This phenomenon leading to the fluctuation of the gap thickness will be

  20. [Development of all-silicone detachable balloons].

    PubMed

    Machida, T; Aoki, S; Sasaki, Y; Sasaki, Y; Iio, M; Matsuno, A; Yoshida, S; Basugi, N

    1990-11-25

    Treatment of cerebral vascular lesions such as carotid cavernous sinus fistulas and giant aneurysms is now being performed with intravascular detachable balloon embolization techniques. We have developed several types of all-silicone detachable balloons. Our balloons have self-sealing valves (with or without collars) and detach with simple traction. The self-sealing valve is smaller than 0.6 mm and the balloon can easily be placed through a 7-F catheter. We started clinical trials and a representative case was reported.

  1. Particle Simulations of Plasma Detachment in VASIMR

    NASA Technical Reports Server (NTRS)

    Ilin, A. V.; ChangDiaz, F. R.; Squire, J. P.; Breizman, B. N.; Carter, M. D.; Novakovski, S. V.

    1999-01-01

    The particle simulations in a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) currently include self-consistent calculation of. 1) stationary magnetic field in plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency heating, 4) ambipolar electric field. The assumptions of quasineutral and collissionless plasma are based on the range of operating VASIMR parameters. The main motivation for the particle simulation in VASIMR is plasma detachment from the magnetic field in the exhaust area. The plasma detachment is caused mainly by the Larmor radius increase. The plasma beta effect on detachment is observed and investigated as well. The results of particle simulations are compared with those from MHD simulations.

  2. [Retinal pigment epithelial detachment in hyperviscosity syndrome].

    PubMed

    Müller, V C; Mihailovic, N; Clemens, C R; Alten, F; Eter, N

    2017-05-15

    We present a case of a 57-year-old woman who reported bilateral visual impairment since 2 weeks. She had a medical history of congenital, cyanotic heart failure. Funduscopic examination revealed serous retinal detachment on the left side, central subneurosensory detachment on the right side, retinal vessel tortuosity and multiple retinal haemorrhages in the periphery. As blood analysis showed a distinct increase in haemoglobin and haematocrit, hyperviscosity syndrome was suspected to have caused bilateral serous retinal detachment. Isovolemic haemodilution was performed in close cooperation with the cardiology department with repeated phlebotomy, which resulted in a significant reduction of subretinal fluid and, concurrently, an increase in visual acuity.

  3. Particle Simulations of Plasma Detachment in VASIMR

    NASA Technical Reports Server (NTRS)

    Ilin, A. V.; ChangDiaz, F. R.; Squire, J. P.; Breizman, B. N.; Carter, M. D.; Novakovski, S. V.

    1999-01-01

    The particle simulations in a Variable Specific Impulse Magnetoplasma Rocket (VASIMR) currently include self-consistent calculation of. 1) stationary magnetic field in plasma, 2) ion density and velocity, 3) ion-cyclotron radio-frequency heating, 4) ambipolar electric field. The assumptions of quasineutral and collissionless plasma are based on the range of operating VASIMR parameters. The main motivation for the particle simulation in VASIMR is plasma detachment from the magnetic field in the exhaust area. The plasma detachment is caused mainly by the Larmor radius increase. The plasma beta effect on detachment is observed and investigated as well. The results of particle simulations are compared with those from MHD simulations.

  4. On plasma detachment in propulsive magnetic nozzles

    SciTech Connect

    Ahedo, Eduardo; Merino, Mario

    2011-05-15

    Three detachment mechanisms proposed in the literature (via resistivity, via electron inertia, and via induced magnetic field) are analyzed with an axisymmetric model of the expansion of a small-beta, weakly collisional, near-sonic plasma in a diverging magnetic nozzle. The model assumes cold, partially magnetized ions and hot, isothermal, fully magnetized electrons. Different conditions of the plasma beam at the nozzle throat are considered. A central feature is that a positive thrust gain in the nozzle of a plasma thruster is intimately related to the azimuthal current in the plasma being diamagnetic. Then, and contrary to existing expectations, the three aforementioned detachment mechanisms are divergent, that is, the plasma beam diverges outwards of the guide nozzle, further hindering its axial expansion and the thrust efficiency. The rate of divergent detachment is quantified for the small-parameter range of the three mechanisms. Alternative mechanisms for a convergent detachment of the plasma beam are suggested.

  5. [Ocular hypertension after surgery for retinal detachment].

    PubMed

    Muşat, O; Cristescu, R; Coman, Corina; Asandi, R

    2012-01-01

    This papers presents a case of a patient with retinal detachement, 3 days ago operated (posterior vitrectomy internal tamponament with silicon oil 1000) who develop increased ocular pressure following silicon oil output in the anterior chamber.

  6. [Intraocular hypertension after retinal detachment surgery].

    PubMed

    Muşat, O; Cristescu, R; Coman, Corina; Asandi, R

    2012-01-01

    This papers presents a case of a patient with retinal detachment, 3 days ago operated (posterior vitrectomy, internal tamponament with silicon oil 1000) who developed increased ocular pressure following silicon oil output in the anterior chamber.

  7. Detached plasma in Saturn's front side magnetosphere

    NASA Technical Reports Server (NTRS)

    Goertz, C. K.

    1983-01-01

    Plasma observations in the outer front side Saturnian magnetosphere are discussed which indicate the existence of dense flux tubes outside the plasma sheets. It is suggested that flux tubes are detached from the plasma sheet by a centifugally driven flute instability. The same instability leads to a dispersal of Titan-injected plasma. It is shown that the detached flux tubes will probably break open as they convect into the nightside magnetotail and lose their content in the form of a planetary wind.

  8. l-Theanine attenuates cadmium-induced neurotoxicity through the inhibition of oxidative damage and tau hyperphosphorylation.

    PubMed

    Ben, Peiling; Zhang, Zhengping; Zhu, Yanyan; Xiong, Aiying; Gao, Yanhong; Mu, Jianyun; Yin, Zhimin; Luo, Lan

    2016-12-01

    Cadmium (Cd) has long been known to induce neurological degenerative disorders. We studied effects of l-theanine, one of the major amino acid components in green tea, on Cd-induced brain injury in mice. Male ICR mice were intraperitoneally injected with l-theanine (100 or 200mg/kg/day) or saline and after one hour these mice were orally administrated with CdCl2 (3.75-6mg/kg). The treatment was conducted for 8 weeks. l-Theanine significantly reduced Cd level in the mouse brain and plasma. Cd-induced neuronal cell death in the mouse cortex and hippocampus were apparently inhibited by l-theanine treatment. l-Theanine also decreased the levels of malondialdehyde (MDA) and ROS, and obviously elevated the levels of glutathione (GSH) and activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) in the mouse brain. Hyperphosphorylation of tau protein is proposed to be an early event for the evolution of tau pathology, and may play an important role in Cd-induced neurodegeneration. Our results showed that l-theanine significantly suppressed Cd-induced tau protein hyperphosphorylation at Ser199, Ser202, and Ser396. Mechanism study showed that l-theanine inhibited the activation of glycogen synthase kinase-3β (GSK-3β) which contributed to the hyperphosphorylation of tau and Cd-induced cytotoxicity. Furthermore, l-theanine reduced Cd-induced cytotoxicity possibly by interfering with the Akt/mTOR signaling pathway. In conclusion, our study indicated that l-theanine protected mice against Cd-induced neurotoxicity through reducing brain Cd level and relieved oxidative damage and tau hyperphosphorylation. Our foundings provide a novel insight into the potential use of l-theanine as prophylactic and therapeutic agents for Cd-induced neurodegenerative diseases.

  9. IGFBP-1 hyperphosphorylation in response to leucine deprivation is mediated by the AAR pathway

    PubMed Central

    Malkani, Niyati; Jansson, Thomas; Gupta, Madhulika B.

    2017-01-01

    Insulin-like growth factor-1 (IGF-I) is the key regulator of fetal growth. IGF-I bioavailability is markedly diminished by IGF binding protein-1 (IGFBP-1) phosphorylation. Leucine deprivation strongly induces IGFBP-1hyperphosphorylation, and plays an important role in fetal growth restriction (FGR). FGR is characterized by decreased amino acid availability, which activates the amino acid response (AAR) and inhibits the mechanistic target of rapamycin (mTOR) pathway. We investigated the role of AAR and mTOR in mediating IGFBP-1 secretion and phosphorylation in HepG2 cells in leucine deprivation. mTOR inhibition (rapamycin or raptor+rictor siRNA), or activation (DEPTOR siRNA) demonstrated a role of mTOR in leucine deprivation-induced IGFBP-1 secretion but not phosphorylation. When the AAR was blocked (U0126, or ERK/GCN2 siRNA), both IGFBP-1 secretion and phosphorylation (Ser101/Ser119/Ser169) due to leucine deprivation were prevented. CK2 inhibition by TBB also attenuated IGFBP-1 phosphorylation in leucine deprivation. These results suggest that the AAR and mTOR independently regulate IGFBP-1 secretion and phosphorylation in leucine deprivation. PMID:25957086

  10. Pericellular innervation of neurons expressing abnormally hyperphosphorylated tau in the hippocampal formation of Alzheimer's disease patients.

    PubMed

    Blazquez-Llorca, Lidia; Garcia-Marin, Virginia; Defelipe, Javier

    2010-01-01

    Neurofibrillary tangles (NFT) represent one of the main neuropathological features in the cerebral cortex associated with Alzheimer's disease (AD). This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons. We have used immunocytochemical techniques and confocal microscopy reconstructions to examine the distribution of PHF-tau-immunoreactive (ir) cells, and their perisomatic GABAergic and glutamatergic innervations in the hippocampal formation and adjacent cortex of AD patients. Furthermore, correlative light and electron microscopy was employed to examine these neurons and the perisomatic synapses. We observed two patterns of staining in PHF-tau-ir neurons, pattern I (without NFT) and pattern II (with NFT), the distribution of which varies according to the cortical layer and area. Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau. At the electron microscope level, a normal looking neuropil with typical symmetric and asymmetric synapses was observed around PHF-tau-ir neurons. These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered.

  11. Pericellular Innervation of Neurons Expressing Abnormally Hyperphosphorylated Tau in the Hippocampal Formation of Alzheimer's Disease Patients

    PubMed Central

    Blazquez-Llorca, Lidia; Garcia-Marin, Virginia; DeFelipe, Javier

    2010-01-01

    Neurofibrillary tangles (NFT) represent one of the main neuropathological features in the cerebral cortex associated with Alzheimer's disease (AD). This neurofibrillary lesion involves the accumulation of abnormally hyperphosphorylated or abnormally phosphorylated microtubule-associated protein tau into paired helical filaments (PHF-tau) within neurons. We have used immunocytochemical techniques and confocal microscopy reconstructions to examine the distribution of PHF-tau-immunoreactive (ir) cells, and their perisomatic GABAergic and glutamatergic innervations in the hippocampal formation and adjacent cortex of AD patients. Furthermore, correlative light and electron microscopy was employed to examine these neurons and the perisomatic synapses. We observed two patterns of staining in PHF-tau-ir neurons, pattern I (without NFT) and pattern II (with NFT), the distribution of which varies according to the cortical layer and area. Furthermore, the distribution of both GABAergic and glutamatergic terminals around the soma and proximal processes of PHF-tau-ir neurons does not seem to be altered as it is indistinguishable from both control cases and from adjacent neurons that did not contain PHF-tau. At the electron microscope level, a normal looking neuropil with typical symmetric and asymmetric synapses was observed around PHF-tau-ir neurons. These observations suggest that the synaptic connectivity around the perisomatic region of these PHF-tau-ir neurons was apparently unaltered. PMID:20631843

  12. Escitalopram Ameliorates Tau Hyperphosphorylation and Spatial Memory Deficits Induced by Protein Kinase A Activation in Sprague Dawley Rats.

    PubMed

    Ren, Qing-Guo; Wang, Yan-Juan; Gong, Wei-Gang; Xu, Lin; Zhang, Zhi-Jun

    2015-01-01

    Here, we investigated the effect of escitalopram pretreatment on protein kinase A (PKA)-induced tau hyperphosphorylation and spatial memory deficits in rats using western blot and behavioral tests, respectively. We demonstrated that escitalopram effectively ameliorated tau hyperphosphorylation and the spatial memory deficits induced by PKA activation. We measured the total and activity-dependent Ser9-phosphorylated levels of glycogen synthase kinase (GSK)-3β in hippocampal extracts. No significant change in the total level of GSK-3β was observed between the different groups. However, compared with forskolin injection alone, pretreatment with escitalopram increased the level of Ser9-phosphorylated GSK-3β. We also demonstrated that escitalopram increased Akt phosphorylation at Ser473 (the active form of Akt). Furthermore, we identified other important kinases and phosphatases, such as protein phosphatase 2A, extracellular signal-regulated kinases 1 and 2, and MAP kinase kinase-1/2, that have previously been reported to play a crucial role in tau phosphorylation; however, we did not detect any significant change in the activation of these kinases or phosphatases in our study. We unexpectedly demonstrated that forskolin caused anxiety-like behavior in rats, and pretreatment with escitalopram did not significantly ameliorate the anxiety-like behavior induced by forskolin. These data provide the first evidence that escitalopram ameliorates forskolin-induced tau hyperphosphorylation and spatial memory impairment in rats; these effects do not occur via the anti-anxiety activity of escitalopram but may involve the Akt/GSK-3β signaling pathway.

  13. Widespread hyperphosphorylated tau in the working memory circuit early after cortical impact injury of brain (Original study).

    PubMed

    Zhao, Zi-Ai; Ning, Ya-Lei; Li, Ping; Yang, Nan; Peng, Yan; Xiong, Ren-Ping; Zhao, Yan; Liu, Dong; Zeng, Xu-Jia; Chen, Jiang-Fan; Zhou, Yuan-Guo

    2017-04-14

    A series of neurological and psychiatric symptoms occur after traumatic brain injury (TBI), with cognitive dysfunction being one of the most prominent sequela. Given that tau hyperphosphorylation is an important cause of cognitive impairment in patients of Alzheimer's disease, our present study detected the presence of hyperphosphorylated tau (p-tau), mainly at Ser404, in multiple brain regions, including the ipsilateral parietal cortex, contralateral hippocampus and prefrontal cortex, immediately after the injury in a mouse TBI model; these changes lasted for at least 4w. All of these brain regions play important roles in working memory. Hyperphosphorylated tau protein was primarily located in neurons and was accompanied by axonal injury and dendritic spine degeneration. Our study demonstrated that p-tau spreads gradually and selectively from the injured cortex to other brain regions after TBI and that all of the affected regions are part of the working memory circuit. These findings provide experimental support for the role of p-tau in cognitive impairment in the early phase after TBI.

  14. Combustion-derived nanoparticles, the neuroenteric system, cervical vagus, hyperphosphorylated alpha synuclein and tau in young Mexico City residents.

    PubMed

    Calderón-Garcidueñas, Lilian; Reynoso-Robles, Rafael; Pérez-Guillé, Beatriz; Mukherjee, Partha S; Gónzalez-Maciel, Angélica

    2017-11-01

    Mexico City (MC) young residents are exposed to high levels of fine particulate matter (PM2.5), have high frontal concentrations of combustion-derived nanoparticles (CDNPs), accumulation of hyperphosphorylated aggregated α-synuclein (α-Syn) and early Parkinson's disease (PD). Swallowed CDNPs have easy access to epithelium and submucosa, damaging gastrointestinal (GI) barrier integrity and accessing the enteric nervous system (ENS). This study is focused on the ENS, vagus nerves and GI barrier in young MC v clean air controls. Electron microscopy of epithelial, endothelial and neural cells and immunoreactivity of stomach and vagus to phosphorylated ɑ-synuclein Ser129 and Hyperphosphorylated-Tau (Htau) were evaluated and CDNPs measured in ENS. CDNPs were abundant in erythrocytes, unmyelinated submucosal, perivascular and intramuscular nerve fibers, ganglionic neurons and vagus nerves and associated with organelle pathology. ɑSyn and Htau were present in 25/27 MC gastric,15/26 vagus and 18/27 gastric and 2/26 vagus samples respectively. We strongly suggest CDNPs are penetrating and damaging the GI barrier and reaching preganglionic parasympathetic fibers and the vagus nerve. This work highlights the potential role of CDNPs in the neuroenteric hyperphosphorylated ɑ-Syn and tau pathology as seen in Parkinson and Alzheimer's diseases. Highly oxidative, ubiquitous CDNPs constitute a biologically plausible path into Parkinson's and Alzheimer's pathogenesis. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. Reduced miR-512 and the Elevated Expression of Its Targets cFLIP and MCL1 Localize to Neurons With Hyperphosphorylated Tau Protein in Alzheimer Disease.

    PubMed

    Mezache, Louisa; Mikhail, Madison; Garofalo, Michela; Nuovo, Gerard J

    2015-10-01

    The cause for the neurofibrillary tangles and plaques in Alzheimer disease likely relates to an abnormal accumulation of their key components, which include β-amyloid and hyperphosphorylated tau protein. We segregated Alzheimer brain sections from people with end-stage disease into those with abundant hyperphosphorylated tau protein and those without and compared each to normal brains for global microRNA patterns. A significant reduced expression of several microRNAs, including miR-512, was evident in the Alzheimer brain sections with abundant hyperphosphorylated tau. Immunohistochemistry documented that 2 known targets of microRNA-512, cFLIP and MCL1, were significantly over expressed and each colocalized to neurons with the abnormal tau protein. Analysis for apoptosis including activated caspase-3, increased caspase-4 and caspase-8, apoptosis initiating factor, APAF-1 activity, and the TUNEL assay was negative in the areas where neurons showed hyperphosphorylated tau. MCM2 expression, a marker of neuroprogenitor cells, was significantly reduced in the Alzheimer sections that contained the hyperphosphorylated tau. These results suggest that a basic defect in Alzheimer disease may be the reduced microRNA-driven increased expression of proteins that may alter the apoptotic/antiapoptotic balance of neurons. This, in turn, could lead to the accumulation of key Alzheimer proteins such as hyperphosphorylated tau that ultimately prevent normal neuronal function and lead to disease symptomatology.

  16. Folding of a detachment and fault - Modified detachment folding along a lateral ramp, southwestern Montana, USA

    NASA Astrophysics Data System (ADS)

    Schmidt, Christopher; Whisner, S. Christopher; Whisner, Jennifer B.

    2014-12-01

    The inversion of the Middle Proterozoic Belt sedimentary basin during Late Cretaceous thrusting in Montana produced a large eastwardly-convex salient, the southern boundary of which is a 200 km-long oblique to lateral ramp subtended by a detachment between the Belt rocks and Archean basement. A 10 km-long lateral ramp segment exposes the upper levels of the detachment where hanging wall Belt rocks have moved out over the Paleozoic and Mesozoic section. The hanging wall structure consists of a train of high amplitude, faulted, asymmetrical detachment folds. Initial west-east shortening produced layer parallel shortening fabrics and dominantly strike slip faulting followed by symmetrical detachment folding. 'Lock-up' of movement on the detachment surface produced regional simple shear and caused the detachment folds to become asymmetrical and faulted. Folding of the detachment surface after lock-up modified the easternmost detachment folds further into a southeast-verging, overturned fold pair with a ramp-related fault along the base of the stretched mutual limb.

  17. The Detached Haze Layer in Titan's Mesosphere

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Yelle, R. V.; Vuitton, V.

    2008-12-01

    The Cassini observations reveal the presence of a detached haze layer in Titan's mesosphere at an altitude of 520 km, well above the stratosphere. Observations of scattered light made by the Imaging Science Subsystem (ISS) reveal a clearly defined layer encircling low and mid-latitude regions. The aerosol layer is also detected in stellar occultation measurements of UV extinction by the UltraViolet Imaging Spectrometer (UVIS). The haze is a global and permanent feature of Titan's atmosphere. Furthermore the location of the detached haze layer is coincident with and the likely cause of a local maximum in the temperature profile measured by the Huygens Atmospheric Structure Instrument (HASI). This temperature inversion is also permanent and global, having been detected in ground-based stellar occultations. The correlation between the extinction profile and the temperature maximum imply that the detached haze cannot be due to condensation, as previously suggested. Previously, Voyager high phase angle images at 500 nm revealed a detached haze layer near 350 km, more than 150 km lower than the Cassini layer. Close examination of the Voyager images suggests that the Cassini detached layer at 520 km is a separate phenomenon rather than a change in the Voyager detached layer. Analysis of the observed optical properties suggests that the average size of particles in the Cassini detached layer is < 45 nm, with an imaginary index k < 0.3 at 187.5 nm, while Non-LTE calculations of the temperature perturbation induced by the detached haze show that the average particle size must be greater than 35 nm for reproducing the heating rate implied by the HASI temperature profile. Calculation of the sedimentation velocity of the particles, coupled with the derived number density, imply a mass flux of 1.9-3.2 × 10-14 g cm-2 s-1. This is approximately equal to the mass flux required to explain the main haze layer and suggests that the stratospheric haze is formed primarily by

  18. A mechanical model of retinal detachment

    NASA Astrophysics Data System (ADS)

    Chou, Tom; Siegel, Michael

    2012-08-01

    We present a model of the mechanical and fluid forces associated with exudative retinal detachments where the retinal photoreceptor cells separate, typically from the underlying retinal pigment epithelium (RPE). By computing the total fluid volume flow arising from transretinal, vascular and RPE pump currents, we determine the conditions under which the subretinal fluid pressure exceeds the maximum yield stress holding the retina and RPE together, giving rise to an irreversible, extended retinal delamination. We also investigate localized, blister-like retinal detachments by balancing mechanical tension in the retina with both the retina-RPE adhesion energy and the hydraulic pressure jump across the retina. For detachments induced by traction forces, we find a critical radius beyond which the blister is unstable to growth. Growth of a detached blister can also be driven by inflamed lesions in which the tissue has a higher choroidal hydraulic conductivity, has insufficient RPE pump activity, or has defective adhesion bonds. We determine the parameter regimes in which the blister either becomes unstable to growth, remains stable and finite-sized, or shrinks, allowing possible healing. The corresponding stable blister radius and shape are calculated. Our analysis provides a quantitative description of the physical mechanisms involved in exudative retinal detachments and can help guide the development of retinal reattachment protocols or preventative procedures.

  19. Sodium selenate reduces hyperphosphorylated tau and improves outcomes after traumatic brain injury.

    PubMed

    Shultz, Sandy R; Wright, David K; Zheng, Ping; Stuchbery, Ryan; Liu, Shi-Jie; Sashindranath, Maithili; Medcalf, Robert L; Johnston, Leigh A; Hovens, Christopher M; Jones, Nigel C; O'Brien, Terence J

    2015-05-01

    Traumatic brain injury is a common and serious neurodegenerative condition that lacks a pharmaceutical intervention to improve long-term outcome. Hyperphosphorylated tau is implicated in some of the consequences of traumatic brain injury and is a potential pharmacological target. Protein phosphatase 2A is a heterotrimeric protein that regulates key signalling pathways, and protein phosphatase 2A heterotrimers consisting of the PR55 B-subunit represent the major tau phosphatase in the brain. Here we investigated whether traumatic brain injury in rats and humans would induce changes in protein phosphatase 2A and phosphorylated tau, and whether treatment with sodium selenate-a potent PR55 activator-would reduce phosphorylated tau and improve traumatic brain injury outcomes in rats. Ninety young adult male Long-Evans rats were administered either a fluid percussion injury or sham-injury. A proportion of rats were killed at 2, 24, and 72 h post-injury to assess acute changes in protein phosphatase 2A and tau. Other rats were given either sodium selenate or saline-vehicle treatment that was continuously administered via subcutaneous osmotic pump for 12 weeks. Serial magnetic resonance imaging was acquired prior to, and at 1, 4, and 12 weeks post-injury to assess evolving structural brain damage and axonal injury. Behavioural impairments were assessed at 12 weeks post-injury. The results showed that traumatic brain injury in rats acutely reduced PR55 expression and protein phosphatase 2A activity, and increased the expression of phosphorylated tau and the ratio of phosphorylated tau to total tau. Similar findings were seen in post-mortem brain samples from acute human traumatic brain injury patients, although many did not reach statistical significance. Continuous sodium selenate treatment for 12 weeks after sham or fluid percussion injury in rats increased protein phosphatase 2A activity and PR55 expression, and reduced the ratio of phosphorylated tau to total tau

  20. Hyperphosphorylation of RyRs Underlies Triggered Activity in Transgenic Rabbit Model of LQT2 Syndrome

    PubMed Central

    Terentyev, Dmitry; Rees, Colin M.; Li, Weiyan; Cooper, Leroy L.; Jindal, Hitesh K.; Peng, Xuwen; Lu, Yichun; Terentyeva, Radmila; Odening, Katja E.; Daley, Jean; Bist, Kamana; Choi, Bum-Rak; Karma, Alain; Koren, Gideon

    2015-01-01

    Rationale Loss-of function mutations in HERG potassium channels underlie long QT syndrome (LQTS) type 2 (LQT2), and are associated with fatal ventricular tachyarrhythmia. Previously, most studies focused on plasmamembrane-related pathways involved in arrhythmogenesis in LQTS, while pro-arrhythmic changes in intracellular Ca2+ handling remained unexplored. Objective We investigated the remodeling of Ca2+ homeostasis in ventricular cardiomyocytes derived from transgenic rabbit model of LQT2 in order to determine whether these changes contribute to triggered activity in the form of early afterdepolarizations (EADs). Methods and Results Confocal Ca2+ imaging revealed decrease in amplitude of Ca2+ transients and SR Ca2+ content in LQT2 myocytes. Experiments using SR-entrapped Ca2+ indicator demonstrated enhanced RyR-mediated SR Ca2+ leak in LQT2 cells. Western blot analyses showed increased phosphorylation of RyR in LQT2 myocytes vs. controls. Co-immunoprecipitation experiments demonstrated loss of protein phosphatases type 1 and type 2 from the RyR complex. Stimulation of LQT2 cells with β-adrenergic agonist isoproterenol resulted in prolongation of the plateau of action potentials accompanied by aberrant Ca2+ releases and EADs, which were abolished by inhibition of CaMKII. Computer simulations showed that late aberrant Ca2+ releases caused by RyR hyperactivity promote EADs and underlie the enhanced triggered activity through increased forward mode of NCX1. Conclusions Hyperactive, hyperphosphorylated RyRs due to reduced local phosphatase activity enhance triggered activity in LQT2 syndrome. EADs are promoted by aberrant RyR-mediated Ca2+ releases that are present despite a reduction of sarcoplasmic reticulum (SR) content. Those releases increase forward mode NCX1, thereby slowing repolarization and enabling L-type Ca2+ current reactivation. PMID:25249569

  1. Notch-inducible hyperphosphorylated CREB and its ultradian oscillation in long-term memory formation.

    PubMed

    Zhang, Jiabin; Little, Christopher J; Tremmel, Daniel M; Yin, Jerry C P; Wesley, Cedric S

    2013-07-31

    Notch is a cell surface receptor that is known to regulate developmental processes by establishing physical contact between neighboring cells. Many recent studies show that it also plays an important role in the formation of long-term memory (LTM) in adults, implying that memory formation requires regulation at the level of cell-cell contacts among brain cells. Neither the target of Notch activity in LTM formation nor the underlying mechanism of regulation is known. We report here results of our studies in adult Drosophila melanogaster showing that Notch regulates dCrebB-17A, the CREB protein. CREB is a transcriptional factor that is pivotal for intrinsic and synaptic plasticity involved in LTM formation. Notch in conjunction with PKC activity upregulates the level of a hyperphosphorylated form of CREB (hyper-PO4 CREB) and triggers its ultradian oscillation, both of which are linked to LTM formation. One of the sites that is phosphorylated in hyper-PO4 CREB is serine 231, which is the functional equivalent of mammalian CREB serine 133, the phosphorylation of which is an important regulator of CREB functions. Our data suggest the model that Notch and PKC activities generate a cyclical accumulation of cytoplasmic hyper-PO4 CREB that is a precursor for generating the nuclear CREB isoforms. Cyclical accumulation of CREB might be important for repetitive aspects of LTM formation, such as memory consolidation. Because Notch, PKC, and CREB have been implicated in many neurodegenerative diseases (e.g., Alzheimer's disease), our data might also shed some light on memory loss and dementia.

  2. Amyloid-β and hyperphosphorylated tau synergy drives metabolic decline in preclinical Alzheimer's disease.

    PubMed

    Pascoal, T A; Mathotaarachchi, S; Mohades, S; Benedet, A L; Chung, C-O; Shin, M; Wang, S; Beaudry, T; Kang, M S; Soucy, J-P; Labbe, A; Gauthier, S; Rosa-Neto, P

    2017-02-01

    This study was designed to test the interaction between amyloid-β and tau proteins as a determinant of metabolic decline in preclinical Alzheimer's disease (AD). We assessed 120 cognitively normal individuals with [(18)F]florbetapir positron emission tomography (PET) and cerebrospinal fluid (CSF) measurements at baseline, as well as [(18)F]fluorodeoxyglucose ([(18)F]FDG) PET at baseline and at 24 months. A voxel-based interaction model was built to test the associations between continuous measurements of CSF biomarkers, [(18)F]florbetapir and [(18)F]FDG standardized uptake value ratios (SUVR). We found that the synergistic interaction between [(18)F]florbetapir SUVR and CSF phosphorylated tau (p-tau) measurements, rather than the sum of their independent effects, was associated with a 24-month metabolic decline in basal and mesial temporal, orbitofrontal, and anterior and posterior cingulate cortices (P<0.001). In contrast, interactions using CSF amyloid-β1-42 and total tau biomarkers did not associate with metabolic decline over a time frame of 24 months. The interaction found in this study further support the framework that amyloid-β and hyperphosphorylated tau aggregates synergistically interact to cause downstream AD neurodegeneration. In fact, the regions displaying the metabolic decline reported here were confined to brain networks affected early by amyloid-β plaques and neurofibrillary tangles. Preventive clinical trials may benefit from using a combination of amyloid-β PET and p-tau biomarkers to enrich study populations of cognitively normal subjects with a high probability of disease progression in studies, using [(18)F]FDG as a biomarker of efficacy.

  3. Kinetic dynamics simulation of the detached plasma

    NASA Astrophysics Data System (ADS)

    Pianpanit, Theerasarn; Ishiguro, Seiji; Hasegawa, Hiroki

    2015-11-01

    The detached plasma has been proposed to reduce the heat flux to the divertor. Fluid code has been widely used to investigate the detached plasma but the cooling of plasma, trapped particle effects, and other kinetic dynamics in the detached plasma has not been well understood. Particle-in-Cell (PIC) simulation with the Monte Carlo collisions and the cumulative scattering angle coulomb collision are carried out to study dynamical kinetic behavior of the plasma. The constant pressure and temperature of neutral gas box in front of the divertor target model has been used in the simulation. The results show the decrease in electron temperature in front of the divertor plate strongly relate to the Coulomb collision frequency.

  4. [Binocular vision after treatment of retinal detachment].

    PubMed

    Maksymowicz, Małgorzata; Raczyńska, Krystyna; Maksymowicz, Jarosław

    2003-01-01

    The study covered 79 patients after treatment of retinal detachment. Double vision, strabismus and disturbances of eyeballs motility were found. Up to 12 months after intervention, the deterioration of binocular vision was observed in 48.28 to 89.66% of patients, depending on the method used. The majority of disturbances were observed during the first 3 months with tendency to gradual subsidence during consecutive 9 months. A patient, after treatment of retinal detachment, can be qualified to return to work where stereopsis is needed under condition that ophthalmologic examination is done every three months during the first year after operation and than once a year.

  5. A simple analytical solution for slab detachment

    NASA Astrophysics Data System (ADS)

    Schmalholz, Stefan M.

    2011-04-01

    An analytical solution is presented for the nonlinear dynamics of high amplitude necking in a free layer of power-law fluid extended in layer-parallel direction due to buoyancy stress. The solution is one-dimensional (1-D) and contains three dimensionless parameters: the thinning factor (i.e. ratio of current to initial layer thickness), the power-law stress exponent, n, and the ratio of time to the characteristic deformation time of a viscous layer under buoyancy stress, t/ tc. tc is the ratio of the layer's effective viscosity to the applied buoyancy stress. The value of tc/ n specifies the time for detachment, i.e. the time it takes until the layer thickness has thinned to zero. The first-order accuracy of the 1-D solution is confirmed with 2-D finite element simulations of buoyancy-driven necking in a layer of power-law fluid embedded in a linear or power-law viscous medium. The analytical solution is accurate within a factor about 2 if the effective viscosity ratio between the layer and the medium is larger than about 100 and if the medium is a power-law fluid. The analytical solution is applied to slab detachment using dislocation creep laws for dry and wet olivine. Results show that one of the most important parameters controlling the dynamics of slab detachment is the strength of the slab which strongly depends on temperature and rheological parameters. The fundamental conclusions concerning slab detachment resulting from both the analytical solution and from earlier published thermo-mechanical numerical simulations agree well, indicating the usefulness of the highly simplified analytical solution for better understanding slab detachment. Slab detachment resulting from viscous necking is a combination of inhomogeneous thinning due to varying buoyancy stress within the slab and a necking instability due to the power-law viscous rheology ( n > 1). Application of the analytical solution to the Hindu Kush slab provides no "order-of-magnitude argument" against

  6. Retinal detachment after open globe injury.

    PubMed

    Stryjewski, Tomasz P; Andreoli, Christopher M; Eliott, Dean

    2014-01-01

    To characterize the development of retinal detachment (RD) after open globe trauma. Case-control study. A total of 892 patients comprising 893 open globe injuries (OGIs), of whom 255 were ultimately diagnosed with RD, with the remaining eyes serving as controls. Retrospective chart review of patients with OGIs presenting to the Massachusetts Eye and Ear Infirmary between 1999 and 2011. Kaplan-Meier analysis was used to estimate the time to detachment, and multivariable logistic regression was used to define the clinical factors associated with RD after OGI. Demographic and clinical characteristics at the time of presentation after OGI, date of RD diagnosis, and last date of follow-up. Primary repair of the open globe was typically undertaken within hours of presentation. A total of 255 eyes were ultimately diagnosed with RD after open globe trauma, yielding an incidence of 29% (95% confidence interval, 26-32). For eyes that developed RD, 27% (69/255) detached within 24 hours of primary open globe repair, 47% (119/255) detached within 1 week, and 72% (183/255) detached within 1 month. Multivariable regression analysis revealed the presence of vitreous hemorrhage (odds ratio [OR], 7.29; P < 0.001), higher zone of injury (OR, 2.51 per integer increase in zone number; OR, 1.00-6.30; P < 0.001), and poorer logarithm of the minimum angle of resolution (logMAR) visual acuity at the time of presentation after OGI (OR, 2.41 per integer increase in logMAR visual acuity; OR, 1.00-81.30; P < 0.001) to be associated with RD. A screening tool was created: the Retinal Detachment after Open Globe Injury score. Retinal detachment is common after open globe trauma, although often not appearing until days to weeks after the initial traumatic event. Several clinical variables at the time of initial presentation can predict the future risk of detachment. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.

  7. Visual recovery after macula-off retinal detachment.

    PubMed

    Ross, W H

    2002-07-01

    With modern surgical techniques to repair retinal detachments, a greater than 90% primary anatomic success rate can be expected. Despite this high level of anatomic success, visual results remain compromised mainly because of permanent functional damage once the macula becomes detached. The most important predictor of visual recovery after retinal detachment surgery is preoperative visual acuity. Preoperative acuity appears to be directly related to the height of macular detachment. Shorter duration of detachment and younger age are also important in visual recovery. This paper will review the current literature that helps to improve our understanding of visual recovery after macula-off retinal detachments.

  8. Association of Constitutive Hyperphosphorylation of Hsf1p with a Defective Ethanol Stress Response in Saccharomyces cerevisiae Sake Yeast Strains

    PubMed Central

    Noguchi, Chiemi; Watanabe, Daisuke; Zhou, Yan; Akao, Takeshi

    2012-01-01

    Modern sake yeast strains, which produce high concentrations of ethanol, are unexpectedly sensitive to environmental stress during sake brewing. To reveal the underlying mechanism, we investigated a well-characterized yeast stress response mediated by a heat shock element (HSE) and heat shock transcription factor Hsf1p in Saccharomyces cerevisiae sake yeast. The HSE-lacZ activity of sake yeast during sake fermentation and under acute ethanol stress was severely impaired compared to that of laboratory yeast. Moreover, the Hsf1p of modern sake yeast was highly and constitutively hyperphosphorylated, irrespective of the extracellular stress. Since HSF1 allele replacement did not significantly affect the HSE-mediated ethanol stress response or Hsf1p phosphorylation patterns in either sake or laboratory yeast, the regulatory machinery of Hsf1p is presumed to function differently between these types of yeast. To identify phosphatases whose loss affected the control of Hsf1p, we screened a series of phosphatase gene deletion mutants in a laboratory strain background. Among the 29 mutants, a Δppt1 mutant exhibited constitutive hyperphosphorylation of Hsf1p, similarly to the modern sake yeast strains, which lack the entire PPT1 gene locus. We confirmed that the expression of laboratory yeast-derived functional PPT1 recovered the HSE-mediated stress response of sake yeast. In addition, deletion of PPT1 in laboratory yeast resulted in enhanced fermentation ability. Taken together, these data demonstrate that hyperphosphorylation of Hsf1p caused by loss of the PPT1 gene at least partly accounts for the defective stress response and high ethanol productivity of modern sake yeast strains. PMID:22057870

  9. Association of constitutive hyperphosphorylation of Hsf1p with a defective ethanol stress response in Saccharomyces cerevisiae sake yeast strains.

    PubMed

    Noguchi, Chiemi; Watanabe, Daisuke; Zhou, Yan; Akao, Takeshi; Shimoi, Hitoshi

    2012-01-01

    Modern sake yeast strains, which produce high concentrations of ethanol, are unexpectedly sensitive to environmental stress during sake brewing. To reveal the underlying mechanism, we investigated a well-characterized yeast stress response mediated by a heat shock element (HSE) and heat shock transcription factor Hsf1p in Saccharomyces cerevisiae sake yeast. The HSE-lacZ activity of sake yeast during sake fermentation and under acute ethanol stress was severely impaired compared to that of laboratory yeast. Moreover, the Hsf1p of modern sake yeast was highly and constitutively hyperphosphorylated, irrespective of the extracellular stress. Since HSF1 allele replacement did not significantly affect the HSE-mediated ethanol stress response or Hsf1p phosphorylation patterns in either sake or laboratory yeast, the regulatory machinery of Hsf1p is presumed to function differently between these types of yeast. To identify phosphatases whose loss affected the control of Hsf1p, we screened a series of phosphatase gene deletion mutants in a laboratory strain background. Among the 29 mutants, a Δppt1 mutant exhibited constitutive hyperphosphorylation of Hsf1p, similarly to the modern sake yeast strains, which lack the entire PPT1 gene locus. We confirmed that the expression of laboratory yeast-derived functional PPT1 recovered the HSE-mediated stress response of sake yeast. In addition, deletion of PPT1 in laboratory yeast resulted in enhanced fermentation ability. Taken together, these data demonstrate that hyperphosphorylation of Hsf1p caused by loss of the PPT1 gene at least partly accounts for the defective stress response and high ethanol productivity of modern sake yeast strains.

  10. Electron-impact detachment from B-

    NASA Astrophysics Data System (ADS)

    Andersen, L. H.; Jensen, M. J.; Pedersen, H. B.; Vejby-Christensen, L.; Djurić, N.

    1998-10-01

    Cross sections for electron-impact single and double detachment from B- have been measured from 0 to 200 eV. The single-detachment cross section peaks at 4-5 eV with a cross-section maximum of about 10-14 cm2. A (2p3) 4S state has recently been predicted to give rise to a resonance state in the H2- dianion [T. Sommerfeld et al., Phys. Rev. A 55 1903 (1997)]. We observe no resonances in the detachment cross section of B- and hence no sign of an equivalent shortlived B2-(2p3) state. The ratio of the double- to single-detachment cross section reaches a constant value of 3% at energies above 50 eV. A simple model relates this number to a shake-off probability of about 90%. The ratio between double and single ionization of neutral atomic targets at high energy is also discussed, and the model relates this ratio to the shake-off probability in the sudden approximation.

  11. [Retinal detachment in various myopic refractions].

    PubMed

    Alimanović-Halilović, Emina

    2009-01-01

    The basic aim of this study was to find the group of "critical" myopic refraction with the highest occurrence of retinal detachment. In the study, 180 myopic eyes were analyzed. Upon the targeted ophthalmological anamnesis, definition of the objective refraction, and indirect binocular ophthalmoscopy, we analyzed the distribution of retinal detachment and the area affected in relation to refraction. All the eyes were divided into groups according to the refraction height. Average age of our patients ranged from 48.43 to 51.60 years with SD from 13.88 to 18.45. We did not find a statistically significant difference for a certain age. The study covered 102 (56.6%) male and 78 (43.3%) female patients. The highest occurrence of retinal detachment was found in Refraction Group from 3.5 to 7.49 dsph, total 21 (11.6%). The retinal detachments usually affected 2/4 or 3/4 of the eye fundus surface respectively.

  12. [Retinal detachment with retinoschisis--case report].

    PubMed

    Cristescu, R; Muşat, O; Toma, Oana; Coma, Corina; Gabej, Ioana; Burcea, M

    2013-01-01

    We present the case of a 43 year old patient diagnosed with rhegmatogenous retinal detachment and retinoschizis, a rare case of disease association. Surgery is recommended and we practice 23 gauge vitrectomy, laser retinopexy, criopexy in the periphery and internal heavy oil tamponade. Postoperatory evolution was favorable.

  13. Modeling Detached Plasmas in DIII-D

    NASA Astrophysics Data System (ADS)

    Porter, Gary D.; Rognlien, T. D.; Rensink, M. E.; DIII-D Team

    1996-11-01

    The ITER divertor design relies on operation of the machine with a detached divertor plasma as a means of reducing the divertor heat load to manageable levels. This operating mode has been seen on all of the world's diverted tokamaks, and is characterized by very low plate temperatures and ion currents. Experimental results on DIII-D have shown the plate electron temperature is between 1 and 2 eV. We describe the results of modeling these detached plasmas with the UEDGE code in this paper. Plasma detachment can be achieved in a variety of ways in the code as well as in experiment. Simulations indicate the detachment process occurs in two steps: a thermal collapse in which the plate temperature drops to 1 to 2 eV, followed by a decrease in the plate ion current. When the low temperature region extends off the plate, parallel momentum of the plasma is reduced by ion/neutral interactions. The plate ion current decreases when the parallel momentum is reduced sufficiently to permit volume recombination processes to compete with ion flow to the plate.

  14. Selenomethionine Mitigates Cognitive Decline by Targeting Both Tau Hyperphosphorylation and Autophagic Clearance in an Alzheimer's Disease Mouse Model.

    PubMed

    Zhang, Zhong-Hao; Wu, Qiu-Yan; Zheng, Rui; Chen, Chen; Chen, Yao; Liu, Qiong; Hoffmann, Peter R; Ni, Jia-Zuan; Song, Guo-Li

    2017-03-01

    Tau pathology was recently identified as a key driver of disease progression and an attractive therapeutic target in Alzheimer's disease (AD). Selenomethionine (Se-Met), a major bioactive form of selenium (Se) in organisms with significant antioxidant capacity, reduced the levels of total tau and hyperphosphorylated tau and ameliorated cognitive deficits in younger triple transgenic AD (3xTg-AD) mice. Whether Se-Met has a similar effect on tau pathology and the specific mechanism of action in older 3xTg-AD mice remains unknown. Autophagy is a major self-degradative process to maintain cellular homeostasis and function. Autophagic dysfunction has been implicated in the pathogenesis of multiple age-dependent diseases, including AD. Modulation of autophagy has been shown to retard the accumulation of misfolded and aggregated proteins and to delay the progression of AD. Here, we found that 3xTg-AD mice showed significant improvement in cognitive ability after a 3-month treatment with Se-Met beginning at 8 months of age. In addition to attenuating the hyperphosphorylation of tau by modulating the activity of Akt/glycogen synthase kinase-3β and protein phosphatase 2A, Se-Met-induced reduction of tau was also mediated by an autophagy-based pathway. Specifically, Se-Met improved the initiation of autophagy via the AMP-activated protein kinase-mTOR (mammalian target of rapamycin) signaling pathway and enhanced autophagic flux to promote the clearance of tau in 3xTg-AD mice and primary 3xTg neurons. Thus, our results demonstrate for the first time that Se-Met mitigates cognitive decline by targeting both the hyperphosphorylation of tau and the autophagic clearance of tau in AD mice. These data strongly support Se-Met as a potent nutraceutical for AD therapy.SIGNIFICANCE STATEMENT Selenium has been widely recognized as a vital trace element abundant in the brain with effects of antioxidant, anticancer, and anti-inflammation. In this study, we report that selenomethionine

  15. Vinexin β Interacts with Hepatitis C Virus NS5A, Modulating Its Hyperphosphorylation To Regulate Viral Propagation

    PubMed Central

    Xiong, Wei; Yang, Jie; Wang, Mingzhen; Wang, Hailong; Rao, Zhipeng; Zhong, Cheng; Xin, Xiu; Mo, Lin; Yu, Shujuan

    2015-01-01

    ABSTRACT Hepatitis C virus (HCV) nonstructural protein 5A (NS5A) is essential for HCV genome replication and virion production and is involved in the regulation of multiple host signaling pathways. As a proline-rich protein, NS5A is capable of interacting with various host proteins containing Src homology 3 (SH3) domains. Previous studies have suggested that vinexin, a member of the sorbin homology (SoHo) adaptor family, might be a potential binding partner of NS5A by yeast two-hybrid screening. However, firm evidence for this interaction is lacking, and the significance of vinexin in the HCV life cycle remains unclear. In this study, we demonstrated that endogenously and exogenously expressed vinexin β coimmunoprecipitated with NS5A derived from different HCV genotypes. Two residues, tryptophan (W307) and tyrosine (Y325), in the third SH3 domain of vinexin β and conserved Pro-X-X-Pro-X-Arg motifs at the C terminus of NS5A were indispensable for the vinexin-NS5A interaction. Furthermore, downregulation of endogenous vinexin β significantly suppressed NS5A hyperphosphorylation and decreased HCV replication, which could be rescued by expressing a vinexin β short hairpin RNA-resistant mutant. We also found that vinexin β modulated the hyperphosphorylation of NS5A in a casein kinase 1α-dependent on manner. Taken together, our findings suggest that vinexin β modulates NS5A phosphorylation via its interaction with NS5A, thereby regulating HCV replication, implicating vinexin β in the viral life cycle. IMPORTANCE Hepatitis C virus (HCV) nonstructural protein NS5A is a phosphoprotein, and its phosphorylation states are usually modulated by host kinases and other viral nonstructural elements. Additionally, cellular factors containing Src homology 3 (SH3) domains have been reported to interact with proline-rich regions of NS5A. However, it is unclear whether there are any relationships between NS5A phosphorylation and the NS5A-SH3 interaction, and little is known

  16. Alpha 1-Antichymotrypsin, an Inflammatory Protein Overexpressed in the Brains of Patients with Alzheimer's Disease, Induces Tau Hyperphosphorylation through c-Jun N-Terminal Kinase Activation

    PubMed Central

    Tyagi, Ethika; Fiorelli, Tina; Norden, Michelle

    2013-01-01

    The association of inflammatory proteins with neuritic plaques in the brains of Alzheimer's disease (AD) patients has led to the hypothesis that inflammation plays a pivotal role in the development of pathology in AD. Earlier studies have shown that alpha 1-antichymotrypsin (ACT) enhances amyloid beta fibrillization and accelerated plaque formation in APP transgenic mice. Later studies from our laboratory have shown that purified ACT induces tau hyperphosphorylation and degeneration in neurons. In order to understand the mechanisms by which inflammatory proteins enhance tau hyperphosphorylation, we injected interleukin-1β (IL-1β) intracerebroventricularly into mice expressing human ACT, human tau, or both transgenes. It was found that the hyperphosphorylation of tau in ACT and ACT/htau mice after IL-1β injection correlated with increased phosphorylation of c-Jun N-terminal kinase (JNK). We verified the involvement of JNK in ACT-induced tau phosphorylation by utilizing JNK inhibitors in cultured primary neurons treated with ACT, and we found that the inhibitor showed complete prevention of ACT-induced tau phosphorylation. These results indicate that JNK is one of the major kinases involved in the ACT-mediated tau hyperphosphorylation and suggest that inhibitors of this kinase may protect against inflammation-induced tau hyperphosphorylation and neurodegeneration associated with AD. PMID:24175110

  17. Risk factors of rhegmatogenous retinal detachment associated with choroidal detachment in Chinese patients

    PubMed Central

    Gu, Yong-Hao; Ke, Gen-Jie; Wang, Lin; Gu, Qi-Hong; Zhou, En-Liang; Pan, Hong-Biao; Wang, Shi-Ying

    2016-01-01

    AIM To comprehensively analyze the risk factors of rhegmatogenous retinal detachment (RRD) associated with choroidal detachment (CD). METHODS A total of 265 eyes of 265 consecutive cases of RRD were retrospectively analyzed. All patients had systemic and ophthalmologic examination. CD was diagnosed by indirect ophthalmoscopy, B-scan ultrasonography, and ultrasound biomicroscope (UBM). Each parameter was compared between patients of RRD and rhegmatogenous retinal detachment associated with choroidal detachment (RRDCD). Logistic regression analysis was used to determine the independent risk factors of CD. RESULTS There were 52 eyes (19.62%) with CD. Pseudophakia was more commonly seen in RRDCD (21.15% vs 6.10%, P=0.002). Intraocular pressure (IOP) was lower (8.60±3.62 vs 12.96±3.55, P<0.001), best-corrected visual acuity was worse [3.00 (2.00 to 3.00) vs 1.92 (1.22 to 3.00), P=0.001], and refractive error was more myopic [-4 (-9 to -2) vs -2 (-6 to 0), P=0.007] in RRDCD. Eyes with RRDCD had larger extent of retinal detachment (P=0.007). In RRDCD, 34.62% of eyes presented with multiple holes (P=0.044) and 25.00% with macular holes (P=0.012), compared with 20.66% and 14.08% in RRD. High myopia (P=0.039), low IOP (P=0.017), and larger extent of retinal detachment (P<0.001) were significant and independent risk factors for developing CD. CONCLUSION For CD in RRD, related factors include BCVA, IOP, lens status, refractive error, extent of retinal detachment, number of holes, and macular hole. Larger extent of retinal detachment, high myopia, and low IOP are significant and independent risk factors. PMID:27500106

  18. Subcutaneous liraglutide ameliorates methylglyoxal-induced Alzheimer-like tau pathology and cognitive impairment by modulating tau hyperphosphorylation and glycogen synthase kinase-3β

    PubMed Central

    Qi, Liqin; Chen, Zhou; Wang, Yanping; Liu, Xiaoying; Liu, Xiaohong; Ke, Linfang; Zheng, Zhongjie; Lin, Xiaowei; Zhou, Yu; Wu, Lijuan; Liu, Libin

    2017-01-01

    Memory deterioration and synapse damage with accumulation of β-amyloid and hyperphosphorylated tau are hallmark lesions of Alzheimer’s disease (AD). Methylglyoxal (MG), a key intermediate of glucose metabolism, is elevated in AD brains and modifies Aβ42, increasing misfolding and leading to the accumulation of senile plaques. Liraglutide, an analog of glucagon-like peptide-1 (GLP-1), is neurotrophic and neuroprotective. However, whether liraglutide can protect against AD-like memory-related deficits and tau hyperphosphorylation caused by MG in vivo is not known. Here, we report that MG induces tau hyperphosphorylation and causes ultrastructural hippocampal damage and cognitive impairment in C57BL/6J mice. Liraglutide reduced these effects via activation of the protein kinase B and glycogen synthase kinase-3β pathways. Our data reveal that liraglutide may alleviate AD-like cognitive impairment by decreasing the phosphorylation of tau. PMID:28337257

  19. Effect of preoperative posture and binocular occlusion on retinal detachment.

    PubMed Central

    Lean, J S; Mahmood, M; Manna, R; Chignell, A H

    1980-01-01

    In an unselected series of retinal detachments a 24-hour period of binocular occlusion and posture with a retinal hole dependent produces some resolution of subretinal fluid in 13% of cases. If only patients with acute, freely mobile detachments and retinal holes above the horizontal meridian were selected the proportion of detachments showing some resolution rose to 30%. In 8% of cases a paradoxical response occurred, the detachment increasing in depth or extending to involve an additional area of retina. PMID:7362818

  20. Citalopram attenuates tau hyperphosphorylation and spatial memory deficit induced by social isolation rearing in middle-aged rats.

    PubMed

    Ren, Qing-Guo; Gong, Wei-Gang; Wang, Yan-Juan; Zhou, Qi-Da; Zhang, Zhi-Jun

    2015-05-01

    Social isolation (SI) is considered as a chronic stress. Here, middle-aged rats (8 months) were group or isolation reared for 6 weeks. Following the initial two-week period of rearing, citalopram (10 mg/kg i.p.) was administered for 28 days. Changes in recognition memory, depression and anxiety-like behavior, and phosphorylated tau were investigated. We found that SI did not lead to obvious depression/anxiety-like behavior in middle-aged rats. Memory deficits and increased tau hyperphosphorylation at Tau-1, Ser396 episodes could be almost reversed by citalopram. The level of Ser9-phosphorylated GSK-3β (inactive form) was significantly decreased in the SI group which also could be almost reversed by citalopram, suggesting that the citalopram could prevent GSK-3β from SI-induced overactivation. The melatonin level was decreased in SI group compared with group housed (GH) group, and citalopram could partly restore the level of melatonin. We also found that citalopram could increase MT1 and MT2 in mRNA level. Our results demonstrate that citalopram increases the level of melatonin which negatively regulates GSK-3β and attenuates tau hyperphosphorylation and spatial memory deficit induced by SI in middle-aged rats. Suggesting that SI might constitute a risk factor for Alzheimer's disease (AD), and citalopram may represent a therapeutic strategy for the treatment of AD.

  1. Hereditary cutaneomucosal venous malformations are caused by TIE2 mutations with widely variable hyper-phosphorylating effects

    PubMed Central

    Wouters, Vinciane; Limaye, Nisha; Uebelhoer, Melanie; Irrthum, Alexandre; Boon, Laurence M; Mulliken, John B; Enjolras, Odile; Baselga, Eulalia; Berg, Jonathan; Dompmartin, Anne; Ivarsson, Sten A; Kangesu, Loshan; Lacassie, Yves; Murphy, Jill; Teebi, Ahmad S; Penington, Anthony; Rieu, Paul; Vikkula, Miikka

    2010-01-01

    Mutations in the angiopoietin receptor TIE2/TEK have been identified as the cause for autosomal dominantly inherited cutaneomucosal venous malformation (VMCM). Thus far, two specific germline substitutions (R849W and Y897S), located in the kinase domain of TIE2, have been reported in five families. The mutations result in a fourfold increase in ligand-independent phosphorylation of the receptor. Here, we report 12 new families with TEK mutations. Although the phenotype is primarily characterized by small multifocal cutaneous vascular malformations, many affected members also have mucosal lesions. In addition, cardiac malformations are observed in some families. Six of the identified mutations are new, with three located in the tyrosine kinase domain, two in the kinase insert domain, and another in the carboxy terminal tail. The remaining six are R849W substitutions. Overexpression of the new mutants resulted in ligand-independent hyperphosphorylation of the receptor, suggesting this is a general feature of VMCM-causative TIE2 mutations. Moreover, variation in the level of activation demonstrates, to the best of our knowledge for the first time, that widely differing levels of chronic TIE2 hyperphosphorylation are tolerated in the heterozygous state, and are compatible with normal endothelial cell function except in the context of highly localized areas of lesion pathogenesis. PMID:19888299

  2. Involvement of I2PP2A in the abnormal hyperphosphorylation of tau and its reversal by Memantine.

    PubMed

    Chohan, Muhammad Omar; Khatoon, Sabiha; Iqbal, Inge-Grundke; Iqbal, Khalid

    2006-07-10

    The activity of protein phosphatase (PP)-2A, which regulates tau phosphorylation, is compromised in Alzheimer disease brain. Here we show that the transient transfection of PC12 cells with inhibitor-2 (I2PP2A) of PP2A causes abnormal hyperphosphorylation of tau at Ser396/Ser404 and Ser262/Ser356. This hyperphosphorylation of tau is observed only when a sub-cellular shift of I2PP2A takes place from the nucleus to the cytoplasm and is accompanied by cleavage of I2PP2A into a 20 kDa fragment. Memantine, an un-competitive inhibitor of N-methyl-D-aspartate receptors, inhibits this abnormal phosphorylation of tau and cell death and prevents the I2PP2A-induced inhibition of PP2A activity in vitro. These findings demonstrate novel mechanisms by which I2PP2A regulates the intracellular activity of PP2A and phosphorylation of tau, and by which Memantine modulates PP2A signaling and inhibits neurofibrillary degeneration.

  3. Glucagon-like peptide-1 protects hippocampal neurons against advanced glycation end product-induced tau hyperphosphorylation.

    PubMed

    Chen, S; An, F-M; Yin, L; Liu, A-R; Yin, D-K; Yao, W-B; Gao, X-D

    2014-01-03

    We have previously demonstrated that glucagon-like peptide-1 (GLP-1) receptor agonist ameliorated neurodegenerative changes in rat models of diabetes-related Alzheimer's disease (AD), and protected neurons from glucose toxicity in vitro. Herein, we investigated the effects of GLP-1 receptor mediates on cell toxicity and tau hyperphosphorylation induced by advanced glycation end products (AGEs), which are associated with glucose toxicity, and the molecular mechanism in PC12 cells and the primary hippocampal neurons. Our study demonstrated that the similar protection effects of GLP-1 existed in PC12 cells treated with glucose-bovine serum albumin (BSA) in hyperglycemic conditions or with glycoaldehyde-BSA alone. Additionally, glucose-BSA alone did not induce significant cytotoxicity in PC12 cells, but resulted in tau hyperphosphorylation in primary hippocampal neurons in 24h. And we found that GLP-1 could reduce cell tau phosphorylation induced by high glucose or glucose-BSA. Furthermore, our data in the present study suggested that GLP-1 regulated tau phosphorylation induced by AGEs through a signaling pathway involving glycogen synthase kinase 3β (GSK-3β), similarly to the GSK-3β inhibitor, lithium chloride. Our findings suggest that GLP-1 can protect neurons from diabetes-associated AGE insults in vitro, and provide new evidence for a potential therapeutic value of GLP-1 receptor agonist in the treatment of AD especially diabetes-related AD.

  4. Overactivation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiates accumulation of hyperphosphorylated tau in rat hippocampus after transient middle cerebral artery occlusion.

    PubMed

    Xu, Cheng-Shi; Liu, An-Chun; Chen, Juan; Pan, Zhi-Yong; Wan, Qi; Li, Zhi-Qiang; Wang, Ze-Fen

    2015-08-01

    Middle cerebral artery occlusion (MCAO) induces secondary damages in the hippocampus that is remote from primary ischemic regions. Tau hyperphosphorylation is an important risk for neurodegenerative diseases. Increased tau phosphorylation has been identified in ischemic cortex, but little is known regarding the changes in the hippocampus. We showed that unilateral transient MCAO induced accumulation of hyperphosphorylated tau and concurrent dephosphorylation of glycogen synthase kinase-3β at Ser 9 in the ipsilateral hippocampus. These MCAO-induced changes were not reproduced when glutamatergic inputs from the entorhinal cortex to the hippocampus were transected; however, the changes were mimicked by intrahippocampal N-methyl-d-aspartate (NMDA) administration. Inhibition of NMDA receptor (NMDAR) subunit NR2B, but not NR2A activity in the hippocampus attenuated the accumulation of hyperphosphorylated tau and spatial cognitive impairment in MCAO rats. Together, our data suggest that overactivation of NR2B-containing NMDARs through entorhinal-hippocampal connection plays an important role in the accumulation of hyperphosphorylated tau in the hippocampus following MCAO. Glycogen synthase kinase-3β is an important protein kinase involved in NMDARs-mediated tau hyperphosphorylation. This study indicates that early inhibition of NR2B-containing NMDARs may represent a potential strategy to prevent or delay the occurrence of post-stroke dementia. Middle cerebral artery occlusion induces secondary damage in the hippocampus that is remote from primary ischemic regions. We propose that excessive activation of NR2B-containing NMDA receptors through entorhinal-hippocampal connection initiated the accumulation of hyperphosphorylated tau in the hippocampus, which subsequently induced cognitive deficit. This study provides new insights into the prospects of NR2B inhibition in stoke therapy.

  5. Controlled Detachment of Chemically Glued Cells.

    PubMed

    Koo, Heebeom; Hahn, Sei Kwang; Yun, Seok Hyun

    2016-11-16

    We demonstrate a chemically detachable cell-glue system based on linkers containing disulfide bonds as well as functional groups for metabolic glycoengineering and bioorthogonal click chemistry. Azide groups are generated on the cell surface by metabolic glycoengineering, and they are further modified into tetrazine (Tz) or trans-cyclooctene (TCO) using rationally designed cross-linkers. When the Tz-modified and TCO-modified cells are mixed together, cell gluing between these two cell groups is established by Tz-TCO click chemistry. This artificial cell-cell adhesion can be broken by the administration of glutathione (5 mM), which triggers the degradation of disulfide bonds. Both the gluing and detachment processes are rapid (<10 min) and minimally cytotoxic.

  6. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    Detached crystal growth technique (dewetting) offers improvement in the quality of the grown crystals by preventing sticking to the walls of the crucible and thus reducing the possibility of parasitic nucleation and formation of lattice defects upon cooling. One of the factors relevant for the phenomena is the pressure differential across the meniscus at the crystal-melt interface. We investigated this effect experimentally. The growth took place in closed ampoules under the pressure of an inert gas (forming gas: 96% Ar + 4% H2). The pressure above the melt was adjustable and allowed for a control of the pressure difference between the top and bottom menisci. The crystals were characterized, particularly by taking profilometer measurements along the grown crystals surface. The effects of the experimental conditions on the detachment were compared with those predicted based on the theory of Duffar et al.

  7. Rhegmatogenous retinal detachment and conventional surgical treatment.

    PubMed

    Golubovic, M

    2013-01-01

    The aim of the paper was to present the efficacy and indications for application of conventional surgical treatment of retinal detachment by using external implants, that is,application of encircling band and buckle. This study comprised patients from the University Eye Clinic in Skopje. A total of 33 patients were diagnosed and surgically treated in the period between May 2010 and August 2011. Conventional surgery was applied in smaller number of patients whose changes of the vitreous body were manifested by detachment of posterior hyaloid membrane, syneresis, with appearance of a small number of pigment cells in the vitreous body and synchysis, and the very retina was with fresh detachment without folds or epiretinal changes (that is, PVR A grade). There were a larger number of patients with more distinct proliferative changes of the vitreous body and of the retina, grades PVR B to C1-C2, and who also underwent the same surgical approach. Routine ophthalmologic examinations were performed, including: determination of visual acuity by Snellen's optotypes, determination of eye pressure with Schiotz's tonometer, examination of anterior segment on biomicroscopy, indirect biomicroscopy of posterior eye segment (vitreous body and retina) and examination on biomicroscopy with Goldmann prism, B scan echography of the eyes before and after surgical treatment. Conventional treatment was used by external application of buckle or application of buckle and encircling band. In case of one break, radial buckle was applied and in case of multiple breaks in one quadrant limbus parallel buckle was applied. Besides buckle, encircling band was applied in patients with total or subtotal retinal detachment with already present distinct changes in the vitreous body (PVR B or C1-C2) and degenerative changes in the vitreous body. Breaks were closed with cryopexy. The results obtained have shown that male gender was predominant and that the disease was manifested in younger male adults

  8. Detached Growth of Germanium by Directional Solidification

    NASA Technical Reports Server (NTRS)

    Palosz, W.; Volz, M.; Cobb, S.; Motakef, S.; Szofran, F. R.

    2004-01-01

    Detached crystal growth technique (dewetting) offers improvement in the quality of the grown crystals by preventing sticking to the walls of the crucible and thus reducing the possibility of parasitic nucleation and formation of lattice defects upon cooling. One of the factors relevant for the phenomena is the pressure differential across the meniscus at the crystal-melt interface. We investigated this effect experimentally. The growth took place in closed ampoules under the pressure of an inert gas (forming gas: 96% Ar + 4% H2). The pressure above the melt was adjustable and allowed for a control of the pressure difference between the top and bottom menisci. The crystals were characterized, particularly by taking profilometer measurements along the grown crystals surface. The effects of the experimental conditions on the detachment were compared with those predicted based on the theory of Duffar et al.

  9. Mechanism of bubble detachment from vibrating walls

    SciTech Connect

    Kim, Dongjun; Park, Jun Kwon Kang, Kwan Hyoung; Kang, In Seok

    2013-11-15

    We discovered a previously unobserved mechanism by which air bubbles detach from vibrating walls in glasses containing water. Chaotic oscillation and subsequent water jets appeared when a wall vibrated at greater than a critical level. Wave forms were developed at water-air interface of the bubble by the wall vibration, and water jets were formed when sufficiently grown wave-curvatures were collapsing. Droplets were pinched off from the tip of jets and fell to the surface of the glass. When the solid-air interface at the bubble-wall attachment point was completely covered with water, the bubble detached from the wall. The water jets were mainly generated by subharmonic waves and were generated most vigorously when the wall vibrated at the volume resonant frequency of the bubble. Bubbles of specific size can be removed by adjusting the frequency of the wall's vibration.

  10. Responsive systems for cell sheet detachment.

    PubMed

    Patel, Nikul G; Zhang, Ge

    2013-01-01

    Cell sheet engineering has been progressing rapidly during the past few years and has emerged as a novel approach for cell based therapy. Cell sheet harvest technology enables fabrication of viable, transplantable cell sheets for various tissue engineering applications. Currently, the majority of cell sheet studies use thermo-responsive systems for cell sheet detachment. However, other responsive systems began showing their potentials for cell sheet harvest. This review provides an overview of current techniques in creating cell sheets using different types of responsive systems including thermo-responsive, electro-responsive, photo-responsive, pH-responsive and magnetic systems. Their mechanism, approach, as well as applications for cell detachment have been introduced. Further development of these responsive systems will allow efficient cell sheet harvesting and patterning of cells to reconstruct complex tissue for broad clinical applications.

  11. Tonic Shock Induces Detachment of Giardia lamblia

    PubMed Central

    Hansen, Wendy R.; Fletcher, Daniel A.

    2008-01-01

    Background The parasite Giardia lamblia must remain attached to the host small intestine in order to proliferate and subsequently cause disease. However, little is known about the factors that may cause detachment in vivo, such as changes in the aqueous environment. Osmolality within the proximal small intestine can vary by nearly an order of magnitude between host fed and fasted states, while pH can vary by several orders of magnitude. Giardia cells are known to regulate their volume when exposed to changes in osmolality, but the short-timescale effects of osmolality and pH on parasite attachment are not known. Methodology and Principal Findings We used a closed flow chamber assay to test the effects of rapid changes in media osmolality, tonicity, and pH on Giardia attachment to both glass and C2Bbe-1 intestinal cell monolayer surfaces. We found that Giardia detach from both surfaces in a tonicity-dependent manner, where tonicity is the effective osmolality experienced by the cell. Detachment occurs with a characteristic time constant of 25 seconds (SD = 10 sec, n = 17) in both hypo- and hypertonic media but is otherwise insensitive to physiologically relevant changes in media composition and pH. Interestingly, cells that remain attached are able to adapt to moderate changes in tonicity. By exposing cells to a timed pattern of tonicity variations and adjustment periods, we found that it is possible to maximize the tonicity change experienced by the cells, overcoming the adaptive response and resulting in extensive detachment. Conclusions and Significance These results, conducted with human-infecting Giardia on human intestinal epithelial monolayers, highlight the ability of Giardia to adapt to the changing intestinal environment and suggest new possibilities for treatment of giardiasis by manipulation of tonicity in the intestinal lumen. PMID:18270543

  12. [Treatment of retinal detachment with macular hole].

    PubMed

    Pikulski, Z; Nawrocki, J; Dziegielewski, K

    1993-01-01

    The methods and results of surgery in 6 cases of retinal detachment with macular hole are presented. In all 6 cases pars plana vitrectomy was performed, in 4 with subsequent SF6 and in 2 with silicone oil tamponade. Retinal attachment was achieved in 4 eyes. Visual acuity 1/50-2/50 was found after surgery in 5 cases. The follow-up ranged from 6 to 9 months.

  13. [Treatment of retinal detachment with macular hole].

    PubMed

    Pikulski, Z; Nawrocki, J; Dziegielewski, K

    1993-06-01

    The authors presented 6 cases of macular hole retinal detachment in which pars plana vitrectomy with endo-tamponade was performed; in 4 cases SF6 gas and in 2, with PVR silicone oil was used. Retina was completely attached in 4 eyes. Visual acuity 1/50 to 2/50 was achieved in 5 eyes. Follow-up ranged from 5 to 9 months.

  14. Retinal detachment: is reparative surgery always mandatory?

    PubMed Central

    Jarrett, W H

    1988-01-01

    The author reports 16 cases of rhegmatogenous retinal detachment in which, for a variety of reasons, immediate reparative surgery was not carried out. To date, one-half of these cases have not been operated, and four have been followed for 6 years or longer. No case suffered visual loss because of the delay in surgery, nor has chronic inflammation, glaucoma, or rubeosis been a problem. The clinical characteristics of this group of cases is defined. PMID:2979020

  15. WIDE-FIELD INFRARED IMAGING: A Descriptive Review of Characteristics of Retinoschisis, Retinal Detachment, and Schisis Detachments.

    PubMed

    Ho, Vincent Y; Wehmeier, Jarrod M; Shah, Gaurav K

    2016-08-01

    Retinoschisis and retinal detachments are primarily differentiated based on characteristic examination findings. In diagnostically challenging cases, noncontact wide-field infrared imaging can help diagnosis and visualize the extent/margins of retinoschisis, retinal detachment, or combined schisis detachments by comparing reflectivity patterns. This is a retrospective, observational, descriptive case series of 14 eyes of 14 nonconsecutive patients, ranging from 28 to 89 years old (mean 61), diagnosed with retinoschisis, retinal detachment, or schisis detachment from May 5, 2014 to March 4, 2015. Patients with secondary retinoschisis and/or retinal detachment from other causes were not included in the study. Heidelberg Wide-Field Module lens and Heidelberg Spectralis HRA+OCT machine (Heidelberg Engineering, Heidelberg, Germany) were used to obtain noncontact, wide-field infrared images on each study eye. Seven eyes with retinal detachments, four with retinoschises, and three with schisis detachments were imaged using this novel wide-field infrared technique. Retinoschisis appears light and translucent with prominent vasculature, retinal detachments appear dark and opaque, and combined retinoschisis/retinal detachment exhibit mixed reflectivity patterns. Wide-field infrared imaging provides a quick, noncontact, noninvasive method to accurately diagnose and to monitor for progression of retinoschisis, retinal detachment, or combined schisis detachments.

  16. Detached Growth of Germanium and Germaniumsilicon

    NASA Technical Reports Server (NTRS)

    Dold, P.; Schweizer, M.; Szofran, F.; Benz, K. W.

    1999-01-01

    Up to now, detached growth was observed mainly under microgravity, i.e. under the absence of hydrostatic pressure that hinders the formation of a free melt meniscus. the detached growth of germanium doped with gallium was obtained under 1 g conditions, the growth was performed in quartz-glass ampoule. Part of the crystal grew without wall contact, the detached growth was observed in-situ with a CCD-camera as well as after the growth process in form of growth lines and the formation of <111> facets on the crystal surface. GeSi crystal (oriientation: <111>, maximum silicon content: 4 at%, seed material: Ge) was grown in a pBN crucible (excluding the possibility of in-situ monitoring of the growth process). The grown crystal exhibits three growth facets, indicating also wall free growth. Surface analysis of the crystals (NDIC, SEM) and characterization of crystal segregation (EDAX, resistivity measurement) and defect structure (EPD, x-ray diffraction measurements) will be presented.

  17. Extinguishing ELMs in detached radiative divertor plasmas

    NASA Astrophysics Data System (ADS)

    Pigarov, Alexander; Krasheninnikov, Sergei; Rognlien, Thomas

    2016-10-01

    In order to avoid deleterious effects of ELMs on PFCs in next-step fusion devices it has been suggested to operate with small-sized ELMs naturally extinguishing in the divertor. Our modeling effort is focusing at extinguishing type-I ELMs: conditions for expelled plasma dissipation; efficiency of ELM power handling by detached radiative divertors; and the ELM impact on detachment state. Here time-dependent modeling of a sequence of many ELMs was performed with 2-D edge plasma transport code UEDGE-MB-W which incorporates the Macro-Blob (MB) approach to simulate non-diffusive filamentary transport and various ``Wall'' (W) models for time-dependent hydrogen wall inventory and recycling. Three cases were modeled, in which extinguishing ELMs are achieved due to: (i) intrinsic impurities via graphite sputtering, (ii) extrinsic impurity gas puff (Ne), and (iii) =(i) +(ii). For each case, we performed a series of UEDGE-MB-W runs scanning the deuterium and impurity inventories, pedestal losses and ELM frequency. Temporal variations of the degree of detachment, ionization front shape, recombination sink strength, radiated fraction, peak power loads, OSP, impurity charge states, and in/out asymmetries were analyzed. We discuss the onset of extinguishing ELMs, conditions for not burning through and enhanced plasma recombination as functions of scanned parameters. Efficiencies of intrinsic and extrinsic impurities in ELM extinguishing are compared.

  18. A new scaling for divertor detachment

    DOE PAGES

    Goldston, R. J.; Reinke, M. L.; Schwartz, J. A.

    2017-03-29

    The ITER design, and future reactor designs, depend on divertor `detachment,'whether partial, pronounced or complete, to limit heat flux to plasma-facing components and to limit surface erosion due to sputtering. It would be valuable to have a measure of the difficulty of achieving detachment as a function of machine parameters, such as input power, magnetic field, major radius, etc. Frequently the parallel heat flux, estimated typically as proportional to P-sep/R or PsepB/R, is used as a proxy for this difficulty. Here we argue that impurity cooling is dependent on the upstream density, which itself must be limited by a Greenwald-likemore » scaling. Taking this into account self-consistently, we find the impurity fraction required for detachment scales dominantly as power divided by poloidal magnetic field. The absence of any explicit scaling with machine size is concerning, as P-sep surely must increase greatly for an economic fusion system, while increases in the poloidal field strength are limited by coil technology and plasma physics. This result should be challenged by comparison with 2D divertor codes and with measurements on existing experiments. Nonetheless, it suggests that higher magnetic field, stronger shaping, double-null operation, `advanced' divertor configurations, as well as alternate means to handle heat flux such as metallic liquid and/or vapor targets merit greater attention.« less

  19. Axial eye length after retinal detachment surgery.

    PubMed

    Vukojević, Nenad; Sikić, Jakov; Curković, Tihomir; Juratovac, Zlatko; Katusić, Damir; Sarić, Borna; Jukić, Tomislav

    2005-01-01

    Changes in the eye axial diameter were studied to assess the eye globe impact of conventional operation for retinal detachment. The study included 69 eyes in 69 patients operated on for rhegmatogenous retinal detachment. There were 46.4% of men and 53.6% of women, mean age 52.7 (+/- 15.21) years. Results of preoperative and postoperative ultrasonographic measurement of axial diameter are presented. The mean preoperative and postoperative eye axial diameter was 23.69 (+/- 1.84) mm and 24.43 (+/- 1.91) mm, respectively. Postoperative results showed the axial eye length to increase by a mean of 0.74 (+/- 0.44) mm, yielding a statistically significant difference from the preoperative measurement (p < 0.001). The mean myopia induced by this eyeball elongation was 1.77 D. The encircling band with and without segmental buckling used in surgical repair of retinal detachment creates circular and segmental indentation of the eyeball, thus increasing its axial length. The myopia induced by elongation of the eyeball results in considerable myopia, which requires appropriate correction in the early postoperative period to achieve favorable vision rehabilitation.

  20. Interventions in pseudophakic rhegmatogenous retinal detachment.

    PubMed

    Lauritzen, Derek B; Avila, Marcos P; Buzney, Sheldon M; Weiter, John J

    2002-01-01

    With refinement of vitrectomy techniques over the past 30 years, the treatment of rhegmatogenous retinal detachment (RRD) has transitioned from the almost exclusive use of extraocular techniques to the present time in which intraocular interventions are available and, in some practices, enjoy almost exclusive use for primary repair of RRD. Except for those situations in which a retinal detachment is associated with obvious immediate complications related to the cataract surgery, the considerations for the treatment of pseudophakic RRD are quite similar to those of phakic RRD. The current options are: use of an extraocular buckling device, vitrectomy-related procedures, intraocular gas injection with associated retinopexy, and combinations of these. Disagreement on the ideal intervention for pseudophakic retinal detachment is not uncommon and particularly so in those RRDs which lie somewhere in the spectrum between complex and simple. As is so often the case in the surgical treatment of disease, there may not be one ideal technique for a particular type of RRD; but knowledge of alternatives logically increases the likelihood of a successful result. The goal of this paper is to outline the clinical factors shown to be of importance in deciding which technique will have the greatest chance at not only achieving retinal re-attachment but also in optimizing long-term vision.

  1. Detached Growth of Germanium and Germaniumsilicon

    NASA Technical Reports Server (NTRS)

    Dold, P.; Schweizer, M.; Szofran, F.; Benz, K. W.

    1999-01-01

    Up to now, detached growth was observed mainly under microgravity, i.e. under the absence of hydrostatic pressure that hinders the formation of a free melt meniscus. the detached growth of germanium doped with gallium was obtained under 1 g conditions, the growth was performed in quartz-glass ampoule. Part of the crystal grew without wall contact, the detached growth was observed in-situ with a CCD-camera as well as after the growth process in form of growth lines and the formation of <111> facets on the crystal surface. GeSi crystal (oriientation: <111>, maximum silicon content: 4 at%, seed material: Ge) was grown in a pBN crucible (excluding the possibility of in-situ monitoring of the growth process). The grown crystal exhibits three growth facets, indicating also wall free growth. Surface analysis of the crystals (NDIC, SEM) and characterization of crystal segregation (EDAX, resistivity measurement) and defect structure (EPD, x-ray diffraction measurements) will be presented.

  2. Optimizing the treatment of rhegmatogenous retinal detachment.

    PubMed

    Hajari, Javad Nouri

    2016-03-01

    Surgical approaches for rhegmatogenous retinal detachment (RRD) have evolved rapidly in the past century. This has resulted in an increase in the anatomical success rate from zero per cent in the beginning of the 1900s to now almost 100 per cent. Rhegmatogenous retinal detachment is regarded as an acute eye disease that needs immediate treatment. With the increasing number of cataract surgeries and an increased elderly population, the numbers of RRD occurrences are increasing. The aim of this thesis is to create knowledge on how treatment and care of RRD patients can be optimized. In the first paper, data on the incidence of RRD in Denmark are presented based on data from a nation register the National Patient Registry (NPR). It was discovered that the incidence of RRD in Denmark is similar to previous reported numbers and that the incidence has been increasing due to increasing numbers of cataract surgeries and an increased elderly population. Using data from the NPR, we estimated that the risk of a RRD occurring on the fellow eye is 100 times larger than on the first eye and that middle aged men have the highest risk. Having an increase in the incidence of RRD we need to ensure that the patients are also treated in the most optimal way. To ensure this, an indicator is needed to monitor the quality at the different centres. This indicator presented in the second paper is based in the occurrence of redetachment. We define a detachment to be caused by poor surgery if the retina detaches within one year after initial surgery with pneumatic retinopexy, scleral buckling and VTX with gas, and one and a half years after surgery with VTX with oil. Also lack of oil removal within the first year is a failed operation. It is widely accepted that RRD is an acute disease but when should surgery be performed to attain the most optimal result? In the third paper, we evaluated the progression of posterior RRD with an optical coherence tomography to make an objective assessment of

  3. Coastal Response, a system of detached breakwaters

    NASA Astrophysics Data System (ADS)

    García Ortiz, Isabelo; Negro Valdecantos, Vicente; Santos López, Jose; Esteban, María Dolores

    2017-04-01

    The coastline's sedimentary response in the form of a tombolo or semi-tombolo (salient) as a result of the construction of detached breakwaters is an aspect that should be known in the design phase so that these marine structures may be properly designed. In achieving an ecological, social and economic value, such areas must also be properly managed. All design methods in existence since Dean (1978) are mainly based on hypotheses formulated from geometric studies on existing formations. No relationship at all is established with climate and littoral dynamics typical of the location (only Suh and Darlymple (1987) and the Japanese Ministry of Construction (1986) present relationships depending on wave variables). Neither has the influence on systems with more than two breakwaters been studied. These methods are not fully adapted to the cases existing on the Spanish Mediterranean littoral. The lines of investigation as proposed by L. Bricio and V. Negro (2010) were continued with for this study. These researchers developed a method for dimensioning isolated, detached breakwaters and their semi-tombolo or tombolo associated formations using all the characteristics of the site (energy, geometric and structural), specific climate and geomorphology and littoral dynamics' characteristics. This methodology is currently acknowledged and accepted in works undertaken on the Spanish Mediterranean littoral. A linear regression was obtained in the investigation undertaken on the 18 detached breakwater systems along the whole of the 1670 km of the Spanish Mediterranean littoral using the proposals made by L. Bricio and V. Negro. The adjustment of R2 ≥ 0.90 was used for the sandy, tombolo formations behind all the detached breakwater systems between several non-dimensional monomials displaying the most representative characteristics of the site. L/H12 + (2ṡB)/G =12,15ṡ(X/Xc)+7,3231 X: Distance of breakwaters from coastline Xc: Distance from coastline where the closure depth

  4. Numerical computational of fluid flow through a detached retina

    NASA Astrophysics Data System (ADS)

    Jiann, Lim Yeou; Ismail, Zuhaila; Shafie, Sharidan; Fitt, Alistair

    2015-02-01

    In this paper, a phenomenon of fluid flow through a detached retina is studied. Rhegmatogeneous retinal detachment happens when vitreous humour flow through a detached retina. The exact mechanism of Rhegmatogeneous retinal detachment is complex and remains incomplete. To understand the fluid flow, a paradigm mathematical model is developed and is approximated by the lubrication theory. The numerical results of the velocity profile and pressure distribution are computed by using Finite Element Method. The effects of fluid mechanical on the retinal detachment is discussed and analyzed. Based on the analysis, it is found that the retinal detachment deformation affects the pressure distribution. It is important to comprehend the development of the retinal detachment so that a new treatment method can be developed.

  5. Psychological Detachment in the Relationship between Job Stressors and Strain

    PubMed Central

    Safstrom, My; Hartig, Terry

    2013-01-01

    We investigated the mediating versus moderating role of psychological detachment in the relationship between job stressors and psychological strain. Our sample consisted of 173 university students invested in challenging programs of advanced professional studies, who could find it difficult to detach from work. Hierarchical regression analyses of cross-sectional survey data affirmed the role of psychological detachment as a mediator in the relationship between job demands and perceived stress. Detachment also mediated the relationship between job demands and satisfaction with life, although the association disappeared when controlling for negative affectivity. Detachment did not mediate relationships between job demands and cognitive failures. Psychological detachment did not moderate any of the investigated relationships. The study contributes to a view of psychological detachment as less subject to individual differences than to the imposition of stressors in the given context. PMID:25379246

  6. Effects of ginkgolide A on okadaic acid-induced tau hyperphosphorylation and the PI3K-Akt signaling pathway in N2a cells.

    PubMed

    Chen, Yan; Wang, Cui; Hu, Meili; Pan, Jian; Chen, Jianhua; Duan, Peilu; Zhai, Tianlong; Ding, Jingna; Xu, Cunji

    2012-08-01

    Alzheimer's disease is the most common form of dementia leading to the irreversible loss of neurons, and Tau hyperphosphorylation has an important role in the pathology of Alzheimer's disease. Ginkgolide A is one of the active components of Ginkgo biloba extracts which has been proven to have neuroprotective effects, but the effect of ginkgolide A on Tau hyperphosphorylation has not yet been reported. In this study, the effects of ginkgolide A on cell viability, Tau hyperphosphorylation, and the PI3K-Akt signaling pathway in N2a cell lines were explored, and methods such as the MTT assay, ELISA, and Western blots techniques were used. The results showed that ginkgolide A could increase cell viability and suppress the phosphorylation level of Tau in cell lysates, meanwhile, GSK3β was inhibited with phosphorylation at Ser9. Moreover, treatment of the cells with ginkgolide A promoted phosphorylation of PI3K and Akt, suggesting that the activation of the PI3K-Akt signaling pathway may be the mechanism for ginkgolide A to prevent the intracellular accumulation of p-Tau induced by okadaic acid and to protect the cells from Tau hyperphosphorylation-related toxicity.

  7. ``Detached'' deep earthquakes: are they really?

    NASA Astrophysics Data System (ADS)

    Okal, Emile A.

    2001-12-01

    We use primarily the generation of acoustic T waves into the ocean by deep seismic sources to investigate the propagation of high-frequency seismic energy from the bottom of subduction zones to the shoreline at the earth's surface. Conversion from shear waves to oceanic acoustic waves can be used as a proxy for the existence of a continuous slab featuring low anelastic attenuation. With the help of other techniques, such as the estimation of Q from S-to- P spectral amplitude ratios, we examine systematically a number of regions where earthquakes have been described as "detached". We establish the mechanical continuity of the slab to the hypocenters of the 1990 Sakhalin and 1982 Bonin events, which occurred several hundred kilometers in front of the mainstream seismic zone. The study of the 1989 Paraguay shock is inconclusive, probably due to its much smaller size. The vertical continuity of the South American slab through its aseismic depth range is verified, and a similar situation probably exists in Java. Attenuation data suggests that the deep Spanish earthquakes occur within a vertically large segment of colder material, and a similar situation may exist in Colombia. The only clearly detached deep events with no mechanical connection to the surface make up the Vityaz cluster, under the North Fiji Basin. Based on a variety of geophysical evidence, the small deep earthquakes under New Zealand are likely to take place in a detached blob at least 350 km below the termination of mainstream seismicity. These results support a model integrating buoyancy forces over a long continuous slab as the source of the down-dip compressional stresses observed in large earthquakes at the bottom of the transition zone.

  8. Mediterranean detachment zones : thermicity vs heritage.

    NASA Astrophysics Data System (ADS)

    Labrousse, Loic; Huet, Benjamin; Le Pourhiet, Laetitia; Jolivet, Laurent; Burov, Evgenii

    2017-04-01

    Even if the seminal comprehensive descriptions of Metamorphic Core Complexes (MCCs) in the American Cordillera mentionned lower plates constituted of gneiss and intruded by granites (e. g. Snake Range, Whipple Mountains), the actual definition of MCCs : « Cordilleran metamorphic core complexes appear to be bodies from the middle crust that have been dragged out from beneath fracturing and extending upper crustal rocks, and exposed beneath shallow-dipping (normal slip) faults of large areal extent » {as in Lister & Davis, 1989, Journal of Structural Geology, v. 11, pp. 65-94} refers to rocks exhumed from the middle crust whatever their thermal history. The fundamental property of this middle crust resides in its ability fo flow lateraly toward the forming dome, to accommodate stretching of the upper plate and preserve a relatively flat moho. Even though thermal reequilibration can induce weakening of the lower crust, a similar strength profile can also be inherited from pre-extension evolution of the continental crust and promote development of the original structure of MCCs : their detachment. In order to unravel the rheological meaning of detachments, we propose here a review of extensional shear zones described as detachments in the Mediterranean realm, and establish a three end-members typology with « hot MCCs » as one end-member, and two cold MCC end-members with a weak middle crust due to stacking of high pressure metapelitic nappes or a strong upper crust responsible for the strength contrast exaggeration between the upper and lower crust. New fully coupled thermo-mechanical modeling experiments together with a review of comparable published results allow to test this three end-member typology and determine the critical strength constrast for the perennial development of a detachment zone. A 1000 ratio between the strength at the brittle-ductile transition and the strength at the base of the crust seems a boundary value between localized extensional modes

  9. Plasma Detachment Mechanisms in Propulsive Magnetic Nozzles

    DTIC Science & Technology

    2013-03-07

    Merino and E. Ahedo, Physics of Plasmas 20, 023502 (2013). 26E. Ahedo, J. Gallardo , and M. Mart́ınez-Sánchez, Physics of Plasmas 10, 3397 (2003...Wiley-Blackwell, 2005. 11Ahedo, E., Gallardo , J., and Mart́ınez-Sánchez, M., “Effects of the radial-plasma wall interaction on the axial Hall...detachment References [1] Ahedo, E., Gallardo , J. M., & Mart́ınez-Sánchez, M. (2003). Effects of the radial-plasma wall interaction on the axial Hall

  10. Induction of rapid detachment in Shewanella oneidensis MR-1 biofilms.

    PubMed

    Thormann, Kai M; Saville, Renée M; Shukla, Soni; Spormann, Alfred M

    2005-02-01

    Active detachment of cells from microbial biofilms is a critical yet poorly understood step in biofilm development. We discovered that detachment of cells from biofilms of Shewanella oneidensis MR-1 can be induced by arresting the medium flow in a hydrodynamic biofilm system. Induction of detachment was rapid, and substantial biofilm dispersal started as soon as 5 min after the stop of flow. We developed a confocal laser scanning microscopy-based assay to quantify detachment. The extent of biomass loss was found to be dependent on the time interval of flow stop and on the thickness of the biofilm. Up to 80% of the biomass of 16-h-old biofilms could be induced to detach. High-resolution microscopy studies revealed that detachment was associated with an overall loosening of the biofilm structure and a release of individual cells or small cell clusters. Swimming motility was not required for detachment. Although the loosening of cells from the biofilm structure was observed evenly throughout thin biofilms, the most pronounced detachment in thicker biofilms occurred in regions exposed to the flow of medium, suggesting a metabolic control of detachability. Deconvolution of the factors associated with the stop of medium flow revealed that a sudden decrease in oxygen tension is the predominant trigger for initiating detachment of individual cells. In contrast, carbon limitation did not trigger any substantial detachment, suggesting a physiological link between oxygen sensing or metabolism and detachment. In-frame deletions were introduced into genes encoding the known and putative global transcriptional regulators ArcA, CRP, and EtrA (FNR), which respond to changes in oxygen tension in S. oneidensis MR-1. Biofilms of null mutants in arcA and crp were severely impacted in the stop-of-flow-induced detachment response, suggesting a role for these genes in regulation of detachment. In contrast, an DeltaetrA mutant displayed a variable detachment phenotype. From this genetic

  11. Electron-impact detachment and dissociation of C4- ions

    NASA Astrophysics Data System (ADS)

    Le Padellec, A.; Rabilloud, F.; Pegg, D.; Neau, A.; Hellberg, F.; Thomas, R.; Schmidt, H. T.; Larsson, M.; Danared, H.; Källberg, A.; Andersson, K.; Hanstorp, D.

    2001-12-01

    CRYRING was used to study collision processes between an electron and a negative ion cluster C4-. The total detachment cross sections for the production of the neutral 4C, 3C, 2C, and C fragments were measured. The cross sections for pure detachment, and for detachment plus dissociation leading to the production of C3+C, 2C2, and C2+2C were extracted using a grid. It was found that the pure detachment process overwhelmingly dominates all other fragmentation processes. The threshold location for the detachment channel is found to be around 6.0 eV. Although the doubly charged negative ion C42- has received little previous attention, a defined near-threshold resonance observed in the detachment cross section curve, has been associated with the short-lived state C42- (0.7 fs lifetime).

  12. Kinematic evidence for downdip movement on the Mormon Peak detachment

    NASA Astrophysics Data System (ADS)

    Walker, Christopher D.; Anders, Mark H.; Christie-Blick, Nicholas

    2007-03-01

    The Mormon Peak detachment is considered to be one of the best examples of a rooted upper crustal detachment fault that propagated through the brittle crust at a low angle. The hanging wall of the detachment today consists of a number of isolated blocks that have been interpreted as remnants of a once-contiguous extensional allochthon. Here we present the results of a new study of directional indicators from the basal surfaces beneath these blocks. These measurements do not agree with the long-standing interpretation of a S75°W movement direction for the detachment hanging wall. Instead, the most recent movement on each section of the detachment took place approximately parallel to the present downdip direction. We conclude that the Mormon Peak detachment is best explained as the basal surfaces to a series of rootless gravity slides.

  13. Meniscus Shapes in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K

    2010-01-01

    In detached Bridgman crystal growth, most of the melt is in contact with the ampoule wall, but the crystal is separated from the wall by a small gap, typically 1-100 micrometers. A liquid free surface, or meniscus, bridges across this gap at the position of the melt-crystal interface. Meniscus shapes have been calculated for the case of detached Bridgman growth in cylindrical ampoules by solving the Young-Laplace equation. Key parameters affecting meniscus shapes are the growth angle, contact angle of the meniscus to the ampoule wall, the pressure differential across the meniscus, and the Bond number, a measure of the ratio of gravitational to capillary forces. In general, for specified values of growth and contact angles, solutions exist only over a finite range of pressure differentials. For intermediate values of the Bond number, there are multiple solutions to the Young-Laplace equations. There are also cases where, as a function of pressure differential, existence intervals alternate with intervals where no solutions exist. The implications of the meniscus shape calculations on meniscus stability are discussed.

  14. Management of Giant Retinal Tear Detachments

    PubMed Central

    Berrocal, Maria H.; Chenworth, Megan L.; Acaba, Luis A.

    2017-01-01

    Giant retinal tears (GRTs) are full-thickness circumferential tears of more than 90 degrees of the retina that are associated with vitreous detachment. They are related to ocular trauma, high myopia, aphakia, pseudophakia, genetic mutations involving collagen and young age. GRTs comprise 1.5% of all rhegmatogenous retinal detachments and the average age of incidence is 42 years. GRTs are more common in males, as 72% of all cases occur in males. The incidence of GRTs in the general population is estimated to be 0.05 per 100,000 individuals. Common techniques used in the management of GRTs include fluid-air exchange, pneumatic retinopexy, scleral buckling, primary vitrectomy with gas or silicone oil tamponade, and combined scleral buckle-vitrectomies. However, management of GRTs poses a great challenge to physicians due to the high risk of intra- and post-operative complications and the many technical difficulties involved. The advent of perfluorocarbon liquids (PFCL) and the use of micro-incisional surgery for the treatment of GRTs has provided new opportunities for the management of GTRs. Today, retinal reattachment can be achieved in 94-100% of cases. PMID:28299011

  15. A Sensitivity Analysis of SOLPS Plasma Detachment

    NASA Astrophysics Data System (ADS)

    Green, D. L.; Canik, J. M.; Eldon, D.; Meneghini, O.; AToM SciDAC Collaboration

    2016-10-01

    Predicting the scrape off layer plasma conditions required for the ITER plasma to achieve detachment is an important issue when considering divertor heat load management options that are compatible with desired core plasma operational scenarios. Given the complexity of the scrape off layer, such predictions often rely on an integrated model of plasma transport with many free parameters. However, the sensitivity of any given prediction to the choices made by the modeler is often overlooked due to the logistical difficulties in completing such a study. Here we utilize an OMFIT workflow to enable a sensitivity analysis of the midplane density at which detachment occurs within the SOLPS model. The workflow leverages the TaskFarmer technology developed at NERSC to launch many instances of the SOLPS integrated model in parallel to probe the high dimensional parameter space of SOLPS inputs. We examine both predictive and interpretive models where the plasma diffusion coefficients are chosen to match an empirical scaling for divertor heat flux width or experimental profiles respectively. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility, and is supported under Contracts DE-AC02-05CH11231, DE-AC05-00OR22725 and DE-SC0012656.

  16. The ironic detachment of Edward Gibbon.

    PubMed

    Trosman, Harry

    2009-06-01

    Edward Gibbon, the author of The History of the Decline and Fall of the Roman Empire, has been widely recognized as a master of irony. The historian's early life with parents he found self-serving and unreliable, his reaction to the events surrounding the death of his mother at the age of 9 and the decline of his father, left an impact on his personality and played a role in determining his choice of his life work. Irony has been approached from a psychoanalytic perspective as a mode of communication, as a stylistic device, as a modality through which one might view reality and as a way of uncovering the linkage between pretense and aspiration, between the apparent and the real. Gibbon's ironic detachment can be understood as rooted in his life history. He felt detached from his family of origin, in need of a protective device which would enable him to deal with passion. Sexual and aggressive impulses mobilized defensive postures that were later transformed into an attitude of skepticism and an interest in undercutting false beliefs and irrational authority, positions he attributes to religious ideation which served to instigate historical decline.

  17. Photometric orbits of seven detached eclipsing binaries

    NASA Astrophysics Data System (ADS)

    Popper, D. M.; Etzel, P. B.

    1981-01-01

    Photoelectric light curves of the detached eclipsing binaries V805 Aql, TV Cet, MY Cyg, V478 Cyg, V1143 Cyg, BS Dra, and BK Peg are analyzed. The systems are among those with good spectrographic orbits of both components that are in need of good photometric solutions in order to obtain the absolute properties of the components. The analyses are carried out with a computer program valid for detached systems of spherical or slightly oblate stars in orbits of arbitrary eccentricity. A range of solutions much greater than implied by the internal mean errors of the parameters, is found to give satisfactory fits to the observations. Some of the fits are displayed for a variety of solutions for each system. For the three systems with measurable light variation between eclipses - V478 Cyg, V805 Aql, and MY Cyg - the effect of reflection appears to be substantially less than predicted. Very small, but nonzero, orbital eccentricities are found for four of the systems. The variations of limb darkening with wavelength and with spectral type are found to be in reasonable agreement with predictions from atmospheric theory.

  18. Detection of detachments and inhomogeneities in frescos by Compton scattering

    NASA Astrophysics Data System (ADS)

    Castellano, A.; Cesareo, R.; Buccolieri, G.; Donativi, M.; Palamà, F.; Quarta, S.; De Nunzio, G.; Brunetti, A.; Marabelli, M.; Santamaria, U.

    2005-07-01

    A mobile instrument has been developed for the detection and mapping of detachments in frescos by using Compton back scattered photons. The instrument is mainly composed of a high energy X-ray tube, an X-ray detection system and a translation table. The instrument was first applied to samples simulating various detachment situations, and then transferred to the Vatican Museum to detect detachments and inhomogeneities in the stanza di Eliodoro, one of the "Raphael's stanze".

  19. Detachments of the retinal pigment epithelium at the posterior pole.

    PubMed

    Noble, K G; Levitzky, M J; Carr, R E

    1976-08-01

    Multiple vitelliform cysts of the retina, a disorder of unknown cause in which there are multiple detachments of the retinal pigment epithelium at the posterior pole, occurred in five patients. In four patients all lesions were located outside the parafoveal area while one patient showed bilateral foveal elevations associated with more eccentric detachments. Several patients showed slow resolution of some of the detachments with mild disturbances of the pigment epithelium.

  20. Evolution of the combat and operational stress control detachment.

    PubMed

    Dailey, Jason I; Ijames, Victoria L

    2014-01-01

    Medical units designed to provide combat and operational stress control services have evolved since World War II into the current Combat and Operational Stress Control (COSC) detachments. Yet the structure of these COSC detachments differ greatly between what is authorized in the table of organization and equipment (TO&E) and what is doctrinally described in the current field manual guiding combat and operational stress control operations. We therefore explore the evolution of the COSC detachment, compare the organizations found in current doctrine with that currently authorized on the TO&E, and conclude with a proposed structure of a modern COSC detachment that is functionally modular with more clear chains of command.

  1. [MK-801 or DNQX reduces electroconvulsive shock-induced impairment of learning-memory and hyperphosphorylation of Tau in rats].

    PubMed

    Liu, Chao; Min, Su; Wei, Ke; Liu, Dong; Dong, Jun; Luo, Jie; Liu, Xiao-Bin

    2012-08-25

    This study explored the effect of the excitatory amino acid receptor antagonists on the impairment of learning-memory and the hyperphosphorylation of Tau protein induced by electroconvulsive shock (ECT) in depressed rats, in order to provide experimental evidence for the study on neuropsychological mechanisms improving learning and memory impairment and the clinical intervention treatment. The analysis of variance of factorial design set up two intervention factors which were the electroconvulsive shock (two level: no disposition; a course of ECT) and the excitatory amino acid receptor antagonists (three level: iv saline; iv NMDA receptor antagonist MK-801; iv AMPA receptor antagonist DNQX). Forty-eight adult Wistar-Kyoto (WKY) rats (an animal model for depressive behavior) were randomly divided into six experimental groups (n = 8 in each group): saline (iv 2 mL saline through the tail veins of WKY rats ); MK-801 (iv 2 mL 5 mg/kg MK-801 through the tail veins of WKY rats) ; DNQX (iv 2 mL 5 mg/kg DNQX through the tail veins of WKY rats ); saline + ECT (iv 2 mL saline through the tail veins of WKY rats and giving a course of ECT); MK-801 + ECT (iv 2 mL 5 mg/kg MK-801 through the tail veins of WKY rats and giving a course of ECT); DNQX + ECT (iv 2 mL 5 mg/kg DNQX through the tail veins of WKY rats and giving a course of ECT). The Morris water maze test started within 1 day after the finish of the course of ECT to evaluate learning and memory. The hippocampus was removed from rats within 1 day after the finish of Morris water maze test. The content of glutamate in the hippocampus of rats was detected by high performance liquid chromatography. The contents of Tau protein which included Tau5 (total Tau protein), p-PHF1(Ser396/404), p-AT8(Ser199/202) and p-12E8(Ser262) in the hippocampus of rats were detected by immunohistochemistry staining (SP) and Western blot. The results showed that ECT and the glutamate ionic receptor blockers (NMDA receptor antagonist MK-801 and

  2. Hyperphosphorylated tau in patients with refractory epilepsy correlates with cognitive decline: a study of temporal lobe resections.

    PubMed

    Tai, Xin You; Koepp, Matthias; Duncan, John S; Fox, Nick; Thompson, Pamela; Baxendale, Sallie; Liu, Joan Y W; Reeves, Cheryl; Michalak, Zuzanna; Thom, Maria

    2016-09-01

    SEE BERNASCONI DOI101093/AWW202 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Temporal lobe epilepsy, the most prevalent form of chronic focal epilepsy, is associated with a high prevalence of cognitive impairment but the responsible underlying pathological mechanisms are unknown. Tau, the microtubule-associated protein, is a hallmark of several neurodegenerative diseases including Alzheimer's disease and chronic traumatic encephalopathy. We hypothesized that hyperphosphorylated tau pathology is associated with cognitive decline in temporal lobe epilepsy and explored this through clinico-pathological study. We first performed pathological examination on tissue from 33 patients who had undergone temporal lobe resection between ages 50 and 65 years to treat drug-refractory temporal lobe epilepsy. We identified hyperphosphorylated tau protein using AT8 immunohistochemistry and compared this distribution to Braak patterns of Alzheimer's disease and patterns of chronic traumatic encephalopathy. We quantified tau pathology using a modified tau score created specifically for analysis of temporal lobectomy tissue and the Braak staging, which was limited without extra-temporal brain areas available. Next, we correlated tau pathology with pre- and postoperative cognitive test scores and clinical risk factors including age at time of surgery, duration of epilepsy, history of secondary generalized seizures, history of head injury, handedness and side of surgery. Thirty-one of 33 cases (94%) showed hyperphosphorylated tau pathology in the form of neuropil threads and neurofibrillary tangles and pre-tangles. Braak stage analysis showed 12% of our epilepsy cohort had a Braak staging III-IV compared to an age-matched non-epilepsy control group from the literature (8%). We identified a mixture of tau pathology patterns characteristic of Alzheimer's disease and chronic traumatic encephalopathy. We also found unusual patterns of subpial tau deposition, sparing of the hippocampus and

  3. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described

  4. Crystal Shape Evolution in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2013-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. Existence of the gap provides several advantages, including no sticking of the crystal to the crucible wall, reduced thermal and mechanical stresses, reduced dislocations, and no heterogeneous nucleation by the crucible. Numerical calculations are used to determine the conditions in which a gap can exist. According to crystal shape stability theory, only some of these gap widths will be dynamically stable. Beginning with a crystal diameter that differs from stable conditions, the transient crystal growth process is analyzed. In microgravity, dynamic stability depends only on capillary effects and is decoupled from heat transfer. Depending on the initial conditions and growth parameters, the crystal shape will evolve towards the crucible wall, towards a stable gap width, or towards the center of the crucible, collapsing the meniscus. The effect of a tapered crucible on dynamic stability is also described.

  5. Detachment of a single water drop

    NASA Astrophysics Data System (ADS)

    Chashechkin, Yu. D.; Prokhorov, V. E.

    2014-01-01

    The detachment process of a single water drop from a nozzle made of poorly wetted material is followed using high-speed video equipment. The formation and motion dynamics of various flow components are investigated. These are the drop itself; a liquid bridge (jumper), which connects the drop with the mother liquid; the primary satellite, which is formed from the jumper; and a microsatellite, which is thrown from the satellite and flies to the mother liquid. The strong influence of surface effects, under which the satellite initially moves upward and only at a certain time starts to fall along the ballistic trajectory, is established. Bounce of the microsatellite from the mother liquid, which precedes its absorption, is fixed. It is shown that a stable connection of the formation mechanism of satellites with the jumper dynamics opens the possibility of obtaining uniform-sized drops.

  6. Axial length changes after retinal detachment surgery.

    PubMed

    Burton, T C; Herron, B E; Ossoinig, K C

    1977-01-01

    A-scan echography was an accurate method for detecting changes in the depth of the anterior chamber, lens thickness, and length of the vitreous cavity after retinal detachment surgery in 30 eyes. Approximately 60% of the eyes had significant alterations in axial lengths exceeding+/-0.36 mm in aphakic eyes and +/-0.54 mm in phakic eyes. However, the operation of scleral bucklingg with large segments of hard silicone rubber implants or explants supported by an encircling band failed to result in a significant predictable shift of axial change in phakic or aphakic eyes. A-scan echography showed significant shallowing of the anterior chamber, and scleral buckling significantly increases lens thickness for at least six weeks. This induced a minor myopic refractive change that may explain some of the difference in postoperative refracitons between phakic and aphakic eyes.

  7. Changes in spectral properties of detached leaves

    NASA Technical Reports Server (NTRS)

    Daughtry, C. S. T.; Biehl, L. L.

    1984-01-01

    If leaf senescence can be delayed for several days without significant changes in spectral properties, then samples of leaves at remote test sites could be prepared and shipped to laboratories to measure spectral properties. The changes in spectral properties of detached leaves were determined. Leaves from red birch and red pine were immersed in water or 0.001 M benzylaminopurine (BAP) and stored in plastic bags in the dark at either 5 or 25 C. Total directional-hemispherical reflectance and transmittance of the adaxial surface of birch leaves were measured over the 400 to 1100 nm wavelength region with a spectroradiometer and integrating sphere. Pine needles were taped together and reflectance of the mat of needles was measured. Spectral properties changed less than 5% of initial values during the first week when leaves were stored at 5 C. Storage at 25 C promoted rapid senescence and large changes in spectral properties. BAP delayed, but did not stop, senescence at 25 C.

  8. A detached binary system BK Pegasi

    NASA Astrophysics Data System (ADS)

    Demircan, Osman; Kaya, Yalcin; Tufekcioglu, Zeki

    1994-12-01

    The UBV photometry of the detached F-type eclipsing binary BK Pegasi is presented. The light curve solution by a simple spherical model assumption suggests that a slightly hotter, larger and more luminous primary was eclipsed during the primary minimum. Combined with the radial velocity curves in Popper (1983), it was used to determine anew the system's parameters. The age and the metal abundance of the system were estimated as (3.3 +/- 0.2) x 109 yr and z = 0.028 +/- 0.003 from a comparison with the new grids of stellar models and the isochrones by Schaller et al. (1993). The distance of the system was estimated as 290 pc.

  9. Missed retinal breaks in rhegmatogenous retinal detachment.

    PubMed

    Takkar, Brijesh; Azad, Shorya; Shashni, Adarsh; Pujari, Amar; Bhatia, Indrish; Azad, Rajvardhan

    2016-01-01

    To evaluate the causes and associations of missed retinal breaks (MRBs) and posterior vitreous detachment (PVD) in patients with rhegmatogenous retinal detachment (RRD). Case sheets of patients undergoing vitreo retinal surgery for RRD at a tertiary eye care centre were evaluated retrospectively. Out of the 378 records screened, 253 were included for analysis of MRBs and 191 patients were included for analysis of PVD, depending on the inclusion criteria. Features of RRD and retinal breaks noted on examination were compared to the status of MRBs and PVD detected during surgery for possible associations. Overall, 27% patients had MRBs. Retinal holes were commonly missed in patients with lattice degeneration while missed retinal tears were associated with presence of complete PVD. Patients operated for cataract surgery were significantly associated with MRBs (P=0.033) with the odds of missing a retinal break being 1.91 as compared to patients with natural lens. Advanced proliferative vitreo retinopathy (PVR) and retinal bullae were the most common reasons for missing a retinal break during examination. PVD was present in 52% of the cases and was wrongly assessed in 16%. Retinal bullae, pseudophakia/aphakia, myopia, and horse shoe retinal tears were strongly associated with presence of PVD. Traumatic RRDs were rarely associated with PVD. Pseudophakic patients, and patients with retinal bullae or advanced PVR should be carefully screened for MRBs. Though Weiss ring is a good indicator of PVD, it may still be over diagnosed in some cases. PVD is associated with retinal bullae and pseudophakia, and inversely with traumatic RRD.

  10. Missed retinal breaks in rhegmatogenous retinal detachment

    PubMed Central

    Takkar, Brijesh; Azad, Shorya; Shashni, Adarsh; Pujari, Amar; Bhatia, Indrish; Azad, Rajvardhan

    2016-01-01

    AIM To evaluate the causes and associations of missed retinal breaks (MRBs) and posterior vitreous detachment (PVD) in patients with rhegmatogenous retinal detachment (RRD). METHODS Case sheets of patients undergoing vitreo retinal surgery for RRD at a tertiary eye care centre were evaluated retrospectively. Out of the 378 records screened, 253 were included for analysis of MRBs and 191 patients were included for analysis of PVD, depending on the inclusion criteria. Features of RRD and retinal breaks noted on examination were compared to the status of MRBs and PVD detected during surgery for possible associations. RESULTS Overall, 27% patients had MRBs. Retinal holes were commonly missed in patients with lattice degeneration while missed retinal tears were associated with presence of complete PVD. Patients operated for cataract surgery were significantly associated with MRBs (P=0.033) with the odds of missing a retinal break being 1.91 as compared to patients with natural lens. Advanced proliferative vitreo retinopathy (PVR) and retinal bullae were the most common reasons for missing a retinal break during examination. PVD was present in 52% of the cases and was wrongly assessed in 16%. Retinal bullae, pseudophakia/aphakia, myopia, and horse shoe retinal tears were strongly associated with presence of PVD. Traumatic RRDs were rarely associated with PVD. CONCLUSION Pseudophakic patients, and patients with retinal bullae or advanced PVR should be carefully screened for MRBs. Though Weiss ring is a good indicator of PVD, it may still be over diagnosed in some cases. PVD is associated with retinal bullae and pseudophakia, and inversely with traumatic RRD. PMID:27990367

  11. Stickler syndrome. Epidemiology of retinal detachment.

    PubMed

    Vilaplana, F; Muiños, S J; Nadal, J; Elizalde, J; Mojal, S

    2015-06-01

    A review was performed on all patients with Stickler syndrome that had been treated in our Centre since it was diagnosed, in order to evaluate the risk of suffering a retinal detachment (RD). A total of 14 patients, diagnosed by clinical criteria, were included. The following variables were evaluated: age, gender, ocular background, follow-up, initial and final visual acuity (VA), optical prescription, prophylactic treatment, surgery and techniques performed. The risk age to suffer a RD, as well as cataracts, was determined by using the Kaplan-Meier survival curve analysis. From a total of 5 men and 9 women, the median initial VA was 0.35, which was the same as the final VA. The median optical prescription was -9.5 D myopia. The median of follow-up was 7 years. Ocular background was 4 RD cases and 2 Lasik surgeries. The operations performed were 8 RD, 12 cataract, 2 glaucoma, 2 macular hole, and one endotropia. The median age of RD was 20 years and cataract 34 years. As regards surgical tecnique, 4 scleral buckle cases, and 4 scleral buckle+pars plana vitrectomy cases were formed. The prophylactic treatments performed were: one scleral buckle case, 4 endolaser photocoagulation, and one cryotherapy. Two of which presented with RD. In the series presented, retinal detachment in Stickler syndrome mainly occurs in the second decade of life, with cataracts mainly developing in the fourth decade. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  12. Frictional and elastic energy in gecko adhesive detachment.

    PubMed

    Gravish, Nick; Wilkinson, Matt; Autumn, Kellar

    2008-03-06

    Geckos use millions of adhesive setae on their toes to climb vertical surfaces at speeds of over 1 m s(-1). Climbing presents a significant challenge for an adhesive since it requires both strong attachment and easy, rapid removal. Conventional pressure-sensitive adhesives are either strong and difficult to remove (e.g. duct tape) or weak and easy to remove (e.g. sticky notes). We discovered that the energy required to detach adhering tokay gecko setae (W(d)) is modulated by the angle (theta) of a linear path of detachment. Gecko setae resist detachment when dragged towards the animal during detachment (theta = 30 degrees ) requiring W(d) = 5.0+/-0.86(s.e.) J m(-2) to detach, largely due to frictional losses. This external frictional loss is analogous to viscous internal frictional losses during detachment of pressure-sensitive adhesives. We found that, remarkably, setae possess a built-in release mechanism. Setae acted as springs when loaded in tension during attachment and returned elastic energy when detached along the optimal path (theta=130 degrees ), resulting in W(d) = -0.8+/-0.12 J m(-2). The release of elastic energy from the setal shaft probably causes spontaneous release, suggesting that curved shafts may enable easy detachment in natural, and synthetic, gecko adhesives.

  13. RISK OF MULTIPLE RECURRING RETINAL DETACHMENT AFTER PRIMARY RHEGMATOGENOUS RETINAL DETACHMENT REPAIR.

    PubMed

    Enders, Philip; Schick, Tina; Schaub, Friederike; Kemper, Carolin; Fauser, Sascha

    2017-05-01

    To evaluate functional and anatomical outcomes of patients with retinal redetachments (re-RD) after surgery for primary rhegmatogenous retinal detachment. Medical records of eyes with re-RD after rhegmatogenous retinal detachment surgery between 1999 and 2014 at the Department of Ophthalmology, University of Cologne, Germany, were retrospectively evaluated. Data included preoperative and postoperative clinical findings, best-corrected visual acuity, presence and grade of proliferative vitreoretinopathy, surgical procedures, and complication rates. Three hundred and twenty-eight eyes of 2,457 developed a re-RD (13.3%). Of these 328 eyes, 242 eyes (73.8%) had only one re-RD, whereas 86 eyes (26.2%) had 2 or more re-RDs. Visible presence of proliferative vitreoretinopathy during first redetachment surgery increased risk of re-RD with relative risk ratio of 1.46 (P = 0.05). Best-corrected visual acuity deteriorated with every additional re-RD (P < 0.001). Two hundred and thirty-seven eyes received oil endotamponde at least once. In 91 cases, oil endotamponade was left for long-term until last follow-up. Multiple re-RD (≥2 re-RDs) is an infrequent complication after rhegmatogenous retinal detachment surgery. After a first re-RD occurred, risk for multiple re-RD doubles compared with the risk of a first redetachment. Mean functional outcome is unfavorable, whereas predictability remains nevertheless poor because of the wide range of interindividual postoperative best-corrected visual acuity.

  14. Spontaneous Solitaire™ AB Thrombectomy Stent Detachment During Stroke Treatment

    SciTech Connect

    Akpinar, Suha Yilmaz, Guliz

    2015-04-15

    Spontaneous Solitaire™ stent retriever detachment is a rarely defined entity seen during stroke treatment, which can result in a disastrous clinical outcome if it cannot be solved within a critical stroke treatment time window. Two solutions to this problem are presented in the literature. The first is to leave the stent in place and apply angioplasty to the detached stent, while the second involves surgically removing the stent from the location at which it detached. Here, we present a case of inadvertent stent detachment during stroke treatment for a middle cerebral artery M1 occlusion resulting in progressive thrombosis. The detached stent was removed endovascularly by another Solitaire stent, resulting in the recanalization of the occluded middle cerebral artery.

  15. [Recurrent neurosensory macular detachment in carotid-cavernous fistula].

    PubMed

    de Dompablo, E; Díez-Álvarez, L; Ruiz-Casas, D; Sánchez-Gutiérrez, V; Ciancas, E; González-López, J J

    2015-07-01

    A 46 year-old man was seen in the emergency department complaining of vision loss and exophthalmos in his right eye. He also complained of headache, diplopia of 4 months onset, and neurosensory detachment that resolved spontaneously the month before. The study revealed tortuous conjunctival and episcleral vessels and neurosensory macular detachment in his right eye. A carotid-cavernous fistula was confirmed by computed tomography angiography. The fistula closed spontaneously during the hospitalization. One month later, the neurosensory detachment disappeared again. Carotid-cavernous fistula should be included in the differential diagnosis of neurosensory macular detachments. These neurosensory detachments can resolve spontaneously 11 the fistula is closed. Copyright © 2013 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  16. Cytoplasmic retention of protein phosphatase 2A inhibitor 2 (I2PP2A) induces Alzheimer-like abnormal hyperphosphorylation of Tau.

    PubMed

    Arif, Mohammad; Wei, Jianshe; Zhang, Qi; Liu, Fei; Basurto-Islas, Gustavo; Grundke-Iqbal, Inge; Iqbal, Khalid

    2014-10-03

    Abnormal hyperphosphorylation of Tau leads to the formation of neurofibrillary tangles, a hallmark of Alzheimer disease (AD), and related tauopathies. The phosphorylation of Tau is regulated by protein phosphatase 2A (PP2A), which in turn is modulated by endogenous inhibitor 2 (I2 (PP2A)). In AD brain, I2 (PP2A) is translocated from neuronal nucleus to cytoplasm, where it inhibits PP2A activity and promotes abnormal phosphorylation of Tau. Here we describe the identification of a potential nuclear localization signal (NLS) in the C-terminal region of I2 (PP2A) containing a conserved basic motif, (179)RKR(181), which is sufficient for directing its nuclear localization. The current study further presents an inducible cell model (Tet-Off system) of AD-type abnormal hyperphosphorylation of Tau by expressing I2 (PP2A) in which the NLS was inactivated by (179)RKR(181) → AAA along with (168)KR(169) → AA mutations. In this model, the mutant NLS (mNLS)-I2 (PP2A) (I2 (PP2A)AA-AAA) was retained in the cell cytoplasm, where it physically interacted with PP2A and inhibited its activity. Inhibition of PP2A was associated with the abnormal hyperphosphorylation of Tau, which resulted in microtubule network instability and neurite outgrowth impairment. Expression of mNLS-I2 (PP2A) activated CAMKII and GSK-3β, which are Tau kinases regulated by PP2A. The immunoprecipitation experiments showed the direct interaction of I2 (PP2A) with PP2A and GSK-3β but not with CAMKII. Thus, the cell model provides insights into the nature of the potential NLS and the mechanistic relationship between I2 (PP2A)-induced inhibition of PP2A and hyperphosphorylation of Tau that can be utilized to develop drugs preventing Tau pathology. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Cytoplasmic Retention of Protein Phosphatase 2A Inhibitor 2 (I2PP2A) Induces Alzheimer-like Abnormal Hyperphosphorylation of Tau*

    PubMed Central

    Arif, Mohammad; Wei, Jianshe; Zhang, Qi; Liu, Fei; Basurto-Islas, Gustavo; Grundke-Iqbal, Inge; Iqbal, Khalid

    2014-01-01

    Abnormal hyperphosphorylation of Tau leads to the formation of neurofibrillary tangles, a hallmark of Alzheimer disease (AD), and related tauopathies. The phosphorylation of Tau is regulated by protein phosphatase 2A (PP2A), which in turn is modulated by endogenous inhibitor 2 (I2PP2A). In AD brain, I2PP2A is translocated from neuronal nucleus to cytoplasm, where it inhibits PP2A activity and promotes abnormal phosphorylation of Tau. Here we describe the identification of a potential nuclear localization signal (NLS) in the C-terminal region of I2PP2A containing a conserved basic motif, 179RKR181, which is sufficient for directing its nuclear localization. The current study further presents an inducible cell model (Tet-Off system) of AD-type abnormal hyperphosphorylation of Tau by expressing I2PP2A in which the NLS was inactivated by 179RKR181 → AAA along with 168KR169 → AA mutations. In this model, the mutant NLS (mNLS)-I2PP2A (I2PP2AAA-AAA) was retained in the cell cytoplasm, where it physically interacted with PP2A and inhibited its activity. Inhibition of PP2A was associated with the abnormal hyperphosphorylation of Tau, which resulted in microtubule network instability and neurite outgrowth impairment. Expression of mNLS-I2PP2A activated CAMKII and GSK-3β, which are Tau kinases regulated by PP2A. The immunoprecipitation experiments showed the direct interaction of I2PP2A with PP2A and GSK-3β but not with CAMKII. Thus, the cell model provides insights into the nature of the potential NLS and the mechanistic relationship between I2PP2A-induced inhibition of PP2A and hyperphosphorylation of Tau that can be utilized to develop drugs preventing Tau pathology. PMID:25128526

  18. Tricuspid valve detachment in closure of congenital ventricular septal defect.

    PubMed

    Zhao, Jinping; Li, Jun; Wei, Xiang; Zhao, Bo; Sun, Wei

    2003-01-01

    From January 1991 through December 2001, 600 patients underwent closure of a perimembranous ventricular septal defect through a right atrial approach at our institution. In 122 of these patients, the operation included temporary detachment of a tricuspid valve septal leaflet from the annulus to allow complete visualization of a perimembranous ventricular septal defect The mean age of the patients at surgery was 4.6 years in those who underwent leaflet detachment and 4.7 years in the 478 patients who did not (P > 0.05). Preoperatively, all patients were in sinus rhythm. Echocardiography showed trivial tricuspid regurgitation in 21 of the patients undergoing detachment and in 39 of the non-detachment patients. There was no difference in bypass time or aortic cross-clamp time between the 2 groups. Postoperatively, 3 patients in the non-detachment group had heart block; all other patients were in sinus rhythm. Echocardiograms on the 7th postoperative day showed small residual ventricular septal defects in none of the patients who underwent valve detachment and in 10 of the non-detachment patients; mild tricuspid regurgitation was present in 12 non-detachment patients only; and trivial tricuspid regurgitation was present in 19 patients who underwent valve detachment and in 29 who did not. There was no hospital death in either group. Long-term follow-up showed no progression of tricuspid regurgitation or tricuspid stenosis. All patients remained in sinus rhythm. This study suggests that tricuspid valve detachment is a safe, effective technique that improves exposure for ventricular septal defect repair and does not adversely affect valve competence.

  19. Hyperphosphorylation of polycystin-2 at a critical residue in disease reveals an essential role for polycystin-1-regulated dephosphorylation

    PubMed Central

    Streets, Andrew J.; Wessely, Oliver; Peters, Dorien J.M.; Ong, Albert C.M.

    2013-01-01

    Mutations in PKD1 (85%) or PKD2 (15%) account for almost all cases of autosomal dominant polycystic kidney disease (ADPKD). The ADPKD proteins, termed as polycystin-1 (PC1) and polycystin-2 (PC2), interact via their C-termini to form a receptor–ion channel complex whose function and regulation are not fully understood. Here, we report the first phosphorylated residue (Ser829) in PC2, whose dephosphorylation is mediated by PC1 binding through the recruitment of protein phosphatase-1 alpha (PP1α). Using a new phosphospecific antibody (pPC2) to this site, we demonstrate that Ser829 is phosphorylated by Protein kinase A (PKA) but remains constitutively phosphorylated in cells and tissues lacking PC1. cAMP increased pSer829 basolateral localization in MDCK cells in a time dependent manner and was essential for pronephric development in Xenopus embryos. When constitutively expressed, a complex phenotype associated with enhanced ATP-dependent ER Ca2+ release and loss of growth suppression was observed in cycling cells. These results reveal a reciprocal functional link between PC1 and PC2 which is critically dependent on their interaction. Unopposed cAMP stimulated hyperphosphorylation of PC2 in the absence of functional PC1 could contribute to cyst initiation in PKD1 patients and represents a new molecular paradigm in understanding ADPKD pathogenesis. PMID:23390129

  20. Hyperphosphorylation of polycystin-2 at a critical residue in disease reveals an essential role for polycystin-1-regulated dephosphorylation.

    PubMed

    Streets, Andrew J; Wessely, Oliver; Peters, Dorien J M; Ong, Albert C M

    2013-05-15

    Mutations in PKD1 (85%) or PKD2 (15%) account for almost all cases of autosomal dominant polycystic kidney disease (ADPKD). The ADPKD proteins, termed as polycystin-1 (PC1) and polycystin-2 (PC2), interact via their C-termini to form a receptor-ion channel complex whose function and regulation are not fully understood. Here, we report the first phosphorylated residue (Ser(829)) in PC2, whose dephosphorylation is mediated by PC1 binding through the recruitment of protein phosphatase-1 alpha (PP1α). Using a new phosphospecific antibody (pPC2) to this site, we demonstrate that Ser(829) is phosphorylated by Protein kinase A (PKA) but remains constitutively phosphorylated in cells and tissues lacking PC1. cAMP increased pSer(829) basolateral localization in MDCK cells in a time dependent manner and was essential for pronephric development in Xenopus embryos. When constitutively expressed, a complex phenotype associated with enhanced ATP-dependent ER Ca(2+) release and loss of growth suppression was observed in cycling cells. These results reveal a reciprocal functional link between PC1 and PC2 which is critically dependent on their interaction. Unopposed cAMP stimulated hyperphosphorylation of PC2 in the absence of functional PC1 could contribute to cyst initiation in PKD1 patients and represents a new molecular paradigm in understanding ADPKD pathogenesis.

  1. Nobiletin, a citrus flavonoid, ameliorates cognitive impairment, oxidative burden, and hyperphosphorylation of tau in senescence-accelerated mouse.

    PubMed

    Nakajima, Akira; Aoyama, Yuki; Nguyen, Thuy-Ty Lan; Shin, Eun-Joo; Kim, Hyoung-Chun; Yamada, Shinnosuke; Nakai, Tsuyoshi; Nagai, Taku; Yokosuka, Akihito; Mimaki, Yoshihiro; Ohizumi, Yasushi; Yamada, Kiyofumi

    2013-08-01

    Senescence-accelerated mouse prone 8 (SAMP8) is a model of aging characterized by the early onset of learning and memory impairment and various pathological features of Alzheimer's disease (AD). Our recent studies have demonstrated that nobiletin, a polymethoxylated flavone from citrus peels, ameliorates learning and memory impairment in olfactory-bulbectomized mice, amyloid precursor protein transgenic mice, and NMDA receptor antagonist-treated mice. Here, we present evidence that this natural compound improves age-related cognitive impairment and reduces oxidative stress and tau phosphorylation in SAMP8 mice. Treatment with nobiletin (10 or 50mg/kg) reversed the impairment of recognition memory and context-dependent fear memory in SAMP8 mice. Treatment with nobiletin also restored the decrease in the GSH/GSSG ratio in the brain of SAMP8 mice. In addition, increases in glutathione peroxidase and manganese-superoxide dismutase activities, as well as a decrease in protein carbonyl level, were observed in the brain of nobiletin-treated SAMP8 mice. Furthermore, nobiletin reduced tau phosphorylation in the hippocampus of SAMP8 mice. Together, the markedly beneficial effects of nobiletin represent a potentially useful treatment for ameliorating the learning and memory deficits, oxidative stress, and hyperphosphorylation of tau in aging as well as age-related neurodegenerative diseases such as AD.

  2. Hyperphosphorylation of glucosyl C6 carbons and altered structure of glycogen in the neurodegenerative epilepsy Lafora disease.

    PubMed

    Nitschke, Felix; Wang, Peixiang; Schmieder, Peter; Girard, Jean-Marie; Awrey, Donald E; Wang, Tony; Israelian, Johan; Zhao, XiaoChu; Turnbull, Julie; Heydenreich, Matthias; Kleinpeter, Erich; Steup, Martin; Minassian, Berge A

    2013-05-07

    Laforin or malin deficiency causes Lafora disease, characterized by altered glycogen metabolism and teenage-onset neurodegeneration with intractable and invariably fatal epilepsy. Plant starches possess small amounts of metabolically essential monophosphate esters. Glycogen contains similar phosphate amounts, which are thought to originate from a glycogen synthase error side reaction and therefore lack any specific function. Glycogen is also believed to lack monophosphates at glucosyl carbon C6, an essential phosphorylation site in plant starch metabolism. We now show that glycogen phosphorylation is not due to a glycogen synthase side reaction, that C6 is a major glycogen phosphorylation site, and that C6 monophosphates predominate near centers of glycogen molecules and positively correlate with glycogen chain lengths. Laforin or malin deficiency causes C6 hyperphosphorylation, which results in malformed long-chained glycogen that accumulates in many tissues, causing neurodegeneration in brain. Our work advances the understanding of Lafora disease pathogenesis and suggests that glycogen phosphorylation has important metabolic function. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Long-term treatment with intranasal insulin ameliorates cognitive impairment, tau hyperphosphorylation, and microglial activation in a streptozotocin-induced Alzheimer’s rat model

    PubMed Central

    Guo, Zhangyu; Chen, Yanxing; Mao, Yan-Fang; Zheng, Tingting; Jiang, Yasi; Yan, Yaping; Yin, Xinzhen; Zhang, Baorong

    2017-01-01

    Recent evidence reveals that aberrant brain insulin signaling plays an important role in the pathology of Alzheimer’s disease (AD). Intranasal insulin administration has been reported to improve memory and attention in healthy participants and in AD patients. However, the underlying molecular mechanisms are poorly understood. Here, we treated intracerebroventricular streptozotocin-injected (ICV-STZ) rats, a commonly used animal model of sporadic AD, with daily intranasal delivery of insulin (2 U/day) for 6 consecutive weeks and then studied their cognitive function with the Morris water maze test and biochemical changes via Western blotting. We observed cognitive deficits, tau hyperphosphorylation, and neuroinflammation in the brains of ICV-STZ rats. Intranasal insulin treatment for 6 weeks significantly improved cognitive function, attenuated the level of tau hyperphosphorylation, ameliorated microglial activation, and enhanced neurogenesis in ICV-STZ rats. Additionally, our results indicate that intranasal delivery of insulin probably attenuates tau hyperphosphorylation through the down-regulation of ERK1/2 and CaMKII in the brains of ICV-STZ rats. Our findings demonstrate a beneficial effect of intranasal insulin and provide the mechanistic basis for treating AD patients with intranasal insulin. PMID:28382978

  4. Increases of SET level and translocation are correlated with tau hyperphosphorylation at ser202/thr205 in CA1 of Ts65Dn mice.

    PubMed

    Dorard, Emilie; Gorisse-Hussonnois, Lucie; Guihenneuc-Jouyaux, Chantal; Albac, Christelle; Potier, Marie-Claude; Allinquant, Bernadette

    2016-10-01

    SET is a multifunctional protein, but when present in the cytoplasm, acts as a powerful inhibitor of phosphatase 2A. We previously observed that in CA1 of Down syndrome (DS) patients, the level of SET is increased, and SET is translocated to the cytoplasm and associated with the hyperphosphorylation of tau at ser202/thr205. The presence of SET in the cytoplasm in DS brains may play a role in the progression of the disease. Here, we show that in CA1 of 3-month-old Ts65Dn mice modeling DS, SET level is increased, and SET is translocated to the cytoplasm and associated with tau hyperphosphorylations at ser202/thr205 and with amyloid precursor protein caspase cleaved as observed in Alzheimer disease brains. Tau hyperphosphorylation at ser356 and activation of other phosphatase 2A targets such as the mammalian target of rapamycin and adenosine monophosphate protein kinases were also observed, suggesting deleterious mechanisms. We propose Ts65Dn mice as a model for therapeutic approaches focused on SET overexpression and its cytoplasmic translocation to slow down disease progression. Copyright © 2016 Elsevier Inc. All rights reserved.

  5. Long-term exposure to ELF-MF ameliorates cognitive deficits and attenuates tau hyperphosphorylation in 3xTg AD mice.

    PubMed

    Hu, Yu; Lai, Jinsheng; Wan, Baoquan; Liu, Xingfa; Zhang, Yemao; Zhang, Jiangong; Sun, Dongsheng; Ruan, Guoran; Liu, Enjie; Liu, Gong-Ping; Chen, Chen; Wang, Dao Wen

    2016-03-01

    Although numerous studies have reported the influence of extremely low frequency magnetic field (ELF-MF) exposure on human health, its effects on cognitive deficits in Alzheimer's disease (AD) have remained under debate. Moreover, the influence of ELF-MF on hyperphosphorylated tau, which is one of the most common pathological hallmarks of AD, has not been reported to date. Therefore, transgenic mice (3xTg) were used in the present study. 3xTg mice, which express an APP/PS1 mutation combined with a tau (P301L) mutation and that develop cognitive deficits at 6 months of age, were subjected to ELF-MF (50Hz, 500μT) exposure or sham exposure daily for 3 months. We discovered that ELF-MF exposure ameliorated cognitive deficits and increased synaptic proteins in 3xTg mice. The protective effects of ELF-MF exposure may have also been caused by the inhibition of apoptosis and/or decreased oxidative stress levels that were observed in the hippocampus tissues of treated mice. Furthermore, tau hyperphosphorylation was decreased in vivo because of ELF-MF exposure, and this decrease was induced by the inhibition of GSK3β and CDK5 activities and activation of PP2Ac. We are the first to report that exposure to ELF-MF can attenuate tau phosphorylation. These findings suggest that ELF-MF exposure could act as a valid therapeutic strategy for ameliorating cognitive deficits and attenuating tau hyperphosphorylation in AD.

  6. Differential interaction and aggregation of 3-repeat and 4-repeat tau isoforms with 14-3-3{zeta} protein

    SciTech Connect

    Sadik, Golam; Tanaka, Toshihisa; Kato, Kiyoko; Yanagi, Kentaro; Kudo, Takashi; Takeda, Masatoshi

    2009-05-22

    Tau isoforms, 3-repeat (3R) and 4-repeat tau (4R), are differentially involved in neuronal development and in several tauopathies. 14-3-3 protein binds to tau and 14-3-3/tau association has been found both in the development and in tauopathies. To understand the role of 14-3-3 in the differential regulation of tau isoforms, we have performed studies on the interaction and aggregation of 3R-tau and 4R-tau, either phosphorylated or unphosphorylated, with 14-3-3{zeta}. We show by surface plasmon resonance studies that the interaction between unphosphorylated 3R-tau and 14-3-3{zeta} is {approx}3-folds higher than that between unphosphorylated 4R-tau and 14-3-3{zeta}. Phosphorylation of tau by protein kinase A (PKA) increases the affinity of both 3R- and 4R-tau for 14-3-3{zeta} to a similar level. An in vitro aggregation assay employing both transmission electron microscopy and fluorescence spectroscopy revealed the aggregation of unphosphorylated 4R-tau to be significantly higher than that of unphosphorylated 3R-tau following the induction of 14-3-3{zeta}. The filaments formed from 3R- and 4R-tau were almost similar in morphology. In contrast, the aggregation of both 3R- and 4R-tau was reduced to a similar low level after phosphorylation with PKA. Taken together, these results suggest that 14-3-3{zeta} exhibits a similar role for tau isoforms after PKA-phosphorylation, but a differential role for unphosphorylated tau. The significant aggregation of 4R-tau by 14-3-3{zeta} suggests that 14-3-3 may act as an inducer in the generation of 4R-tau-predominant neurofibrillary tangles in tauopathies.

  7. Hypothesis for the Role of Nutrient Starvation in Biofilm Detachment

    PubMed Central

    Hunt, Stephen M.; Werner, Erin M.; Huang, Baochuan; Hamilton, Martin A.; Stewart, Philip S.

    2004-01-01

    A combination of experimental and theoretical approaches was used to investigate the role of nutrient starvation as a potential trigger for biofilm detachment. Experimental observations of detachment in a variety of biofilm systems were made with pure cultures of Pseudomonas aeruginosa. These observations indicated that biofilms grown under continuous-flow conditions detached after flow was stopped, that hollow cell clusters were sometimes observed in biofilms grown in flow cells, and that lysed cells were apparent in the internal strata of colony biofilms. When biofilms were nutrient starved under continuous-flow conditions, detachment still occurred, suggesting that starvation and not the accumulation of a metabolic product was responsible for triggering detachment in this particular system. A cellular automata computer model of biofilm dynamics was used to explore the starvation-dependent detachment mechanism. The model predicted biofilm structures and dynamics that were qualitatively similar to those observed experimentally. The predicted features included centrally located voids appearing in sufficiently large cell clusters, gradients in growth rate within these clusters, and the release of most of the biofilm with simulated stopped-flow conditions. The model was also able to predict biofilm sloughing resulting solely from this detachment mechanism. These results support the conjecture that nutrient starvation is an environmental cue for the release of microbes from a biofilm. PMID:15574944

  8. Effect of sodium fluoride, ampicillin, and chlorhexidine on Streptococcus mutans biofilm detachment.

    PubMed

    Liu, Jia; Ling, Jun-Qi; Zhang, Kai; Huo, Li-Jun; Ning, Yang

    2012-08-01

    We examined the effect of three clinically used antimicrobials on Streptococcus mutans UA159 biofilm detachment under flow conditions. Sodium fluoride (NaF) and chlorhexidine at MIC levels promoted biofilm detachment and inhibited detachment when concentrations were higher than the MIC and reduced detached-cell viability only at high concentrations. Ampicillin at all concentrations tested inhibited detachment and reduced the percentage of viable biofilm-detached cells. All the three antimicrobial treatments reduced biofilm live/dead cell ratios.

  9. Stability of Menisci in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Mazuruk, Konstantin; Volz, Martin P.

    2013-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The meniscus shape depends on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, the gas pressure differential, the Weber number describing the rotation rate of the crucible, and the Bond number. Only some of the meniscus shapes are stable and the stability criterion is the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The effects of confined gas volumes above and below the melt and crucible rotation are evaluated. The analysis is applicable to the non-stationary case where the crystal radius changes during growth. Static stability maps (crystal radius versus pressure differential) are obtained for a series of Bond numbers, growth angles and Weber numbers. Also, the specific cases of Ge and InSb, in both terrestrial and microgravity conditions, are analyzed. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes are statically stable in a microgravity environment.

  10. Magnetic Nozzle and Plasma Detachment Experiment

    NASA Technical Reports Server (NTRS)

    Chavers, Gregory; Dobson, Chris; Jones, Jonathan; Martin, Adam; Bengtson, Roger D.; Briezman, Boris; Arefiev, Alexey; Cassibry, Jason; Shuttpelz, Branwen; Deline, Christopher

    2006-01-01

    High power plasma propulsion can move large payloads for orbit transfer (such as the ISS), lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue of the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment was performed to test the theory regarding the Magneto-hydrodynamic (MHD) detachment scenario. Data from this experiment will be presented. The Variable Specific Impulse Magnetoplasma Rocket (VASIMR) being developed by the Ad Astra Rocket Company uses a magnetic nozzle as described above. The VASIMR is also a leading candidate for exploiting an electric propulsion test platform being considered for the ISS.

  11. Bubble Growth and Detachment from a Needle

    NASA Astrophysics Data System (ADS)

    Shusser, Michael; Rambod, Edmond; Gharib, Morteza

    1999-11-01

    The release of bubbles from an underwater nozzle or orifice occurs in large number of applications, such as perforated plate columns, blood oxygenators and various methods of water treatment. It is also a widely used method in laboratory research on multiphase flow and acoustics for generating small bubbles in a controlled fashion. We studied experimentally the growth and pinch-off of air bubbles released from a submerged needle into a quiescent liquid or a liquid flowing parallel to the needle. Micron-sized bubbles were generated by an air-liquid dispenser. High-speed imaging was performed to study the formation and detachment of bubbles from the tip of the needle. The impact of the needle diameter was investigated and the size and number of produced bubbles were assessed for different flow rates of air and for different velocities of the imposed upward liquid flow. The results were compared with available theoretical models and numerical computations. The existence of a critical gas flow rate and two regimes of bubble growth were verified.

  12. Observation of mutual neutralization in detached plasma

    NASA Astrophysics Data System (ADS)

    Akira, Tonegawa; Isao, Shirota; Ken'ichi, Yoshida; Masataka, Ono; Kazutaka, Kawamura; Tuguhiro, Watanabe; Nobuyoshi, Ohyabu; Hajime, Suzuki; Kazuo, Takayama

    2001-10-01

    Mutual neutralization in collisions between negative ions and positive ions in molecular activated recombination (MAR) has been observed in a high density magnetized sheet plasma source TPDSHEET-IV(Test Plasma produced by Directed current for SHEET plasma) device. Measurements of the negative ion density of hydrogen atom, the electron density, electron temperature, and the heat load to the target plate were carried out in hydrogen high density plasma with hydrogen gas puff. A cylindrical probe made of tungsten ( 0.4 x 2 cm) was used to measure the spatial profiles of H- by a probe-assisted laser photodetachment The Balmer spectra of visible light emission from hydrogen or helium atoms were detected in front of the target plate. A small amount of secondary hydrogen gas puffing into a hydrogen plasma reduced strongly the heat flux to the target and increased rapidly the density of negative ions of hydrogen atom in the circumference of the plasma, while the conventional radiative and three-body recombination processes were disappeared. These results can be well explained by taking the charge exchange recombination of MAR in the detached plasma into account.

  13. Descemet's Membrane Detachment Management Following Trabeculectomy

    PubMed Central

    Sharifipour, Farideh; Nassiri, Saman; Idan, Aida

    2016-01-01

    Purpose: To present a case of total Descemet's membrane detachment (DMD) after trabeculectomy and its surgical management. Case Report: A 68-year-old woman presented with large DMD and corneal edema one day after trabeculectomy. Intracameral air injection on day 3 was not effective. Choroidal effusion complicated the clinical picture with Descemet's membrane (DM) touching the lens. Choroidal tap with air injection on day 6 resulted in DM attachment and totally clear cornea on the next day. However, on day 12 the same scenario was repeated with choroidal effusion, shallow anterior chamber (AC), and DM touching the lens. The third surgery included transconjunctival closure of the scleral flap with 10/0 nylon sutures, choroidal tap, and intracameral injection of 20% sulfur hexafluoride. After the third surgery, DM remained attached with clear cornea. Suture removal and needling bleb revision preserved bleb function. Lens opacity progressed, and the patient underwent uneventful cataract surgery 4 months later. Conclusion: Scleral flap closure using transconjunctival sutures can be used for DMD after trabeculectomy to make the eye a closed system. Surgical drainage of choroidal effusions should be considered to increase the AC depth. PMID:27621793

  14. Suprachoroidal implantation for the treatment of retinal detachment.

    PubMed

    Poole, T A; Sudarsky, R D

    1986-11-01

    A temporary apposition of retina and choroid has been created during retinal detachment surgery by injection of sodium hyaluronate into the suprachoroidal space in 14 patients. The iatrogenic choroidal detachment lasts at least seven to ten days, allowing adequate time for retinopexy to permanently seal the retinal hole. Suprachoroidal implantation is compatible with and additive to conventional retinal detachment techniques, or it can be used alone as a primary treatment modality. Further clinical evaluation and development are necessary to establish indications and limitations for this technique.

  15. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    A theory describing the shape evolution of detached Bridgman crystals in microgravity has been developed. A starting crystal of initial radius r0 will evolve to one of the following states: Stable detached gap; Attachment to the crucible wall; Meniscus collapse. Only crystals where alpha plus omega is great than 180 degrees will achieve stable detached growth in microgravity. Results of the crystal shape evolution theory are consistent with predictions of the dynamic stability of crystallization (Tatarchenko, Shaped Crystal Growth, Kluwer, 1993). Tests of transient crystal evolution are planned for ICESAGE, a series of Ge and GeSi crystal growth experiments planned to be conducted on the International Space Station (ISS).

  16. Improved Crystal Quality by Detached Solidification in Microgravity

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.

    1999-01-01

    Directional solidification in microgravity has often led to ingots that grew with little or no contact with the ampoule wall. When this occurred, crystallographic perfection was usually greatly improved -- often by several orders of magnitude. Unfortunately, until recently the true mechanisms underlying detached solidification were unknown. As a consequence, flight experiments yielded erratic results. Within the past four years, we have developed a new theoretical model that explains many of the flight results. This model gives rise to predictions of the conditions required to yield detached solidification, both in microgravity and on earth. A discussion of models of detachment, the meniscus models and results of theoretical modeling, and future plans are presented.

  17. Sensitivity of detachment extent to magnetic configuration and external parameters

    NASA Astrophysics Data System (ADS)

    Lipschultz, Bruce; Parra, Felix I.; Hutchinson, Ian H.

    2016-05-01

    Divertor detachment may be essential to reduce heat loads to magnetic fusion tokamak reactor divertor surfaces. Yet in experiments it is difficult to control the extent of the detached, low pressure, plasma region. At maximum extent the front edge of the detached region reaches the X-point and can lead to degradation of core plasma properties. We define the ‘detachment window’ in a given position control variable C (for example, the upstream plasma density) as the range in C within which the front location can be stably held at any position from the target to the X-point; increased detachment window corresponds to better control. We extend a 1D analytic model [1] to determine the detachment window for the following control variables: the upstream plasma density, the impurity concentration and the power entering the scrape-off layer (SOL). We find that variations in magnetic configuration can have strong effects; increasing the ratio of the total magnetic field at the X-point to that at the target, {{B}×}/{{B}t} , (total flux expansion, as in the super-x divertor configuration) strongly increases the detachment window for all control variables studied, thus strongly improving detachment front control and the capability of the divertor plasma to passively accommodate transients while still staying detached. Increasing flux tube length and thus volume in the divertor, through poloidal flux expansion (as in the snowflake or x-divertor configurations) or length of the divertor, also increases the detachment window, but less than the total flux expansion does. The sensitivity of the detachment front location, z h , to each control variable, C, defined as \\partial {{z}h}/\\partial C , depends on the magnetic configuration. The size of the radiating volume and the total divertor radiation increase \\propto {{≤ft({{B}×}/{{B}t}\\right)}2} and \\propto {{B}×}/{{B}t} , respectively, but not by increasing divertor poloidal flux expansion or field line length. We

  18. Vitrectomy, lensectomy and silicone oil tamponade in the management of retinal detachment associated with choroidal detachment

    PubMed Central

    Gui, Jun-Min; Jia, Li; Liu, Lei; Liu, Jian-Di

    2013-01-01

    AIM To report the results of combined vitrectomy, lensectomy and silicone oil (SO) tamponade in treating primary rhegmatogenous retinal detachment (RRD) associated with choroidal detachment (CD). METHODS A retrospective, consecutive and case series study of 21 subjects with concurrent RRD associated with CD was conducted. All subjects underwent a standard three-port 20G pars plana vitrectomy (PPV) with lensectomy and silicone oil tamponade. Mean follow-up time was 8 months (rang from 4 to 19 months). The primary and final anatomic success rate, visual acuity and final intraocular pressure(IOP) were recorded and analyzed. RESULTS Of 21 subjects, 8 were women and 13 were men. Age at presentation ranged from 22 to 75 years (mean 57.4 years). The presenting vision ranged from light perception to 0.15. The initial IOP ranged from 3mmHg to 12mmHg (mean 6.2mmHg). All eyes were phakic except one pseudophakic. No intraocular lens was implanted during the primary surgical intervention. Fifteen of 21 (71.4%) eyes had retina reattached after one operation. Six eyes had recurrent inferior retinal detachment due to proliferation. Five of them were successfully reattached after one or more additional operations. Mean IOP at final follow-up was 15.2mmHg (range from 8mmHg to 20mmHg). One case declined for further operation. The final reattachment rate was 95.2%. Visual acuity improved in 19 (90.5%) eyes, was unchanged in 1 (4.8%) eye and decreased in 1 (4.8%) eye. CONCLUSION Combination of vitrectomy, lensectomy and silicone tamponade is an effective method in treating RRD associated with CD, reducing the incidence of postoperative hypotony. PMID:23826529

  19. Atorvastatin ameliorates cognitive impairment, Aβ1-42 production and Tau hyperphosphorylation in APP/PS1 transgenic mice.

    PubMed

    Zhou, Dongsheng; Liu, Huaxia; Li, Chenli; Wang, Fangyan; Shi, Yaosheng; Liu, Lingjiang; Zhao, Xin; Liu, Aiming; Zhang, Junfang; Wang, Chuang; Chen, Zhongming

    2016-06-01

    Amyloid-beta (Aβ) interacts with the serine/threonine protein kinase AKT (also known as protein kinase B)/glycogen synthase kinase 3β (GSK3β) pathway and deactivates GSK3β signaling, which result in microtubule protein tau phosphorylation. Atorvastatin, a HMG-CoA reductase inhibitor, has been proven to improve learning and memory performance, reduce Aβ and phosphorylated tau levels in mouse model of Alzheimer's disease (AD). However, it still remains unclear whether atorvastatin is responsible for regulation of AKT/GSK3β signaling and contributes to subsequent down-regulation of Aβ1-42 and phosphorylated tau in APP/PS1 transgenic (Tg APP/PS1) mice. Herein, we aimed to investigate the possible impacts of atorvastatin (10 mg/kg, p.o.) on the memory deficit by behavioral tests and changes of AKT/GSK3β signaling in hippocampus and prefrontal cortex by western blot test in Tg APP/PS1 mice. The results showed that treatment with atorvastatin significantly reversed the memory deficit in the Tg APP/PS1 mice in a novel object recognition and the Morris water maze tests. Moreover, atorvastatin significantly attenuated Aβ1-42 accumulation and phosphorylation of tau (Ser396) in the hippocampus and prefrontal cortex of Tg APP/PS1 mice. In addition, atorvastatin treatment also increased phosphorylation of AKT, inhibited GSK3β activity by increasing phosphorylation of GSK3β (Ser9) and decreasing the beta-site APP cleaving enzyme 1 (BACE1) expression. These results indicated that the memory ameliorating effect of atorvastatin may be, in part, by regulation the AKT/GSK3β signaling which may contribute to down-regulation of Aβ1-42 and tau hyperphosphorylation.

  20. Intranasal NAP (davunetide) decreases tau hyperphosphorylation and moderately improves behavioral deficits in mice overexpressing α-synuclein.

    PubMed

    Magen, Iddo; Ostritsky, Regina; Richter, Franziska; Zhu, Chunni; Fleming, Sheila M; Lemesre, Vincent; Stewart, Alistair J; Morimoto, Bruce H; Gozes, Illana; Chesselet, Marie-Françoise

    2014-10-01

    Genome-wide association studies have identified strong associations between the risk of developing Parkinson's disease (PD) and polymorphisms in the genes encoding α-synuclein and the microtubule-associated protein tau. However, the contribution of tau and its phosphorylated form (p-tau) to α-synuclein-induced pathology and neuronal dysfunction remains controversial. We have assessed the effects of NAP (davunetide), an eight-amino acid peptide that decreases tau hyperphosphorylation, in mice overexpressing wild-type human α-synuclein (Thy1-aSyn mice), a model that recapitulates aspects of PD. We found that the p-tau/tau level increased in a subcortical tissue block that includes the striatum and brain stem, and in the cerebellum of the Thy1-aSyn mice compared to nontransgenic controls. Intermittent intranasal NAP administration at 2 μg/mouse per day, 5 days a week, for 24 weeks, starting at 4 weeks of age, significantly decreased the ratio of p-tau/tau levels in the subcortical region while a higher dose of 15 μg/mouse per day induced a decrease in p-tau/tau levels in the cerebellum. Both NAP doses reduced hyperactivity, improved habituation to a novel environment, and reduced olfactory deficits in the Thy1-aSyn mice, but neither dose improved the severe deficits of motor coordination observed on the challenging beam and pole, contrasting with previous data obtained with continuous daily administration of the drug. The data reveal novel effects of NAP on brain p-tau/tau and behavioral outcomes in this model of synucleinopathy and suggest that sustained exposure to NAP may be necessary for maximal benefits.

  1. Polo-Like Kinase 1 Is Involved in Hepatitis C Virus Replication by Hyperphosphorylating NS5A ▿

    PubMed Central

    Chen, Yung-Chia; Su, Wen-Chi; Huang, Jing-Ying; Chao, Ti-Chun; Jeng, King-Song; Machida, Keigo; Lai, Michael M. C.

    2010-01-01

    Hepatitis C virus (HCV) replication involves many viral and host factors. Here, we employed a lentivirus-based RNA interference (RNAi) screening approach to search for possible cellular factors. By using a kinase-phosphatase RNAi library and an HCV replicon reporter system, we identified a serine-threonine kinase, Polo-like kinase 1 (Plk1), as a potential host factor regulating HCV replication. Knockdown of Plk1 reduced both HCV RNA replication and nonstructural (NS) protein production in both HCV replicon cells and HCV-infected cells while it did not significantly affect host cellular growth or cell cycle. Overexpression of Plk1 in the knockdown cells rescued HCV replication. Interestingly, the ratio between the hyperphosphorylated form (p58) and the basal phosphorylated form (p56) of NS5A was lower in the Plk1 knockdown cells and Plk1 kinase inhibitor-treated cells than in the control groups. Further studies showed that Plk1 could be immunoprecipitated together with NS5A. Both proteins partially colocalized in the perinuclear region. Furthermore, Plk1 could phosphorylate NS5A to both the p58 and p56 forms in an in vitro assay system; the phosphorylation efficiency was comparable to that of the reported casein kinase. Taken together, this study shows that Plk1 is an NS5A phosphokinase and thereby indirectly regulates HCV RNA replication. Because of the differential effects of Plk1 on HCV replication and host cell growth, Plk1 could potentially serve as a target for anti-HCV therapy. PMID:20534861

  2. Alzheimer's disease and methanol toxicity (part 1): chronic methanol feeding led to memory impairments and tau hyperphosphorylation in mice.

    PubMed

    Yang, Meifeng; Lu, Jing; Miao, Junye; Rizak, Joshua; Yang, Jianzhen; Zhai, Rongwei; Zhou, Jun; Qu, Jiagui; Wang, Jianhong; Yang, Shangchuan; Ma, Yuanye; Hu, Xintian; He, Rongqiao

    2014-01-01

    Although methanol toxicity is well known for acute neurological sequelae leading to blindness or death, there is a new impetus to investigate the chronic effects of methanol exposure. These include a recently established link between formaldehyde, a methanol metabolite, and Alzheimer's disease (AD) pathology. In the present study, mice were fed with methanol to revisit the chronic effects of methanol toxicity, especially as it pertains to AD progression. Three groups of mice (n = 9) were given either water as a control or a methanol solution (concentrations of 2% or 3.8%) over a 6-week period. The methanol-fed mice were found to have impaired spatial recognition and olfactory memory in Y-maze and olfactory memory paradigms. Immunohistochemical analysis of the mouse brains found increased neuronal tau phosphorylation in the hippocampus and an increased cellular apoptotic marker in hippocampal CA1 neurons (~10% of neurons displayed chromatin condensation) in the methanol-fed groups. Two additional in vitro experiments in mouse embryonic cerebral cortex neurons and mouse neuroblastoma N2a cells found that formaldehyde, but not methanol or the methanol end product formic acid, induced microtubule disintegration and tau protein hyperphosphorylation. The findings of the behavioral tests and immunohistochemical analysis suggested that the methanol-fed mice presented with partial AD-like symptoms. The in vitro experiments suggested that formaldehyde was most likely the detrimental component of methanol toxicity related to hippocampal tau phosphorylation and the subsequent impaired memory in the mice. These findings add to a growing body of evidence that links formaldehyde to AD pathology.

  3. Intranasal NAP (davunetide) decreases tau hyperphosphorylation and moderately improves behavioral deficits in mice overexpressing α-synuclein

    PubMed Central

    Magen, Iddo; Ostritsky, Regina; Richter, Franziska; Zhu, Chunni; Fleming, Sheila M; Lemesre, Vincent; Stewart, Alistair J; Morimoto, Bruce H; Gozes, Illana; Chesselet, Marie-Françoise

    2014-01-01

    Genome-wide association studies have identified strong associations between the risk of developing Parkinson's disease (PD) and polymorphisms in the genes encoding α-synuclein and the microtubule-associated protein tau. However, the contribution of tau and its phosphorylated form (p-tau) to α-synuclein-induced pathology and neuronal dysfunction remains controversial. We have assessed the effects of NAP (davunetide), an eight-amino acid peptide that decreases tau hyperphosphorylation, in mice overexpressing wild-type human α-synuclein (Thy1-aSyn mice), a model that recapitulates aspects of PD. We found that the p-tau/tau level increased in a subcortical tissue block that includes the striatum and brain stem, and in the cerebellum of the Thy1-aSyn mice compared to nontransgenic controls. Intermittent intranasal NAP administration at 2 μg/mouse per day, 5 days a week, for 24 weeks, starting at 4 weeks of age, significantly decreased the ratio of p-tau/tau levels in the subcortical region while a higher dose of 15 μg/mouse per day induced a decrease in p-tau/tau levels in the cerebellum. Both NAP doses reduced hyperactivity, improved habituation to a novel environment, and reduced olfactory deficits in the Thy1-aSyn mice, but neither dose improved the severe deficits of motor coordination observed on the challenging beam and pole, contrasting with previous data obtained with continuous daily administration of the drug. The data reveal novel effects of NAP on brain p-tau/tau and behavioral outcomes in this model of synucleinopathy and suggest that sustained exposure to NAP may be necessary for maximal benefits. PMID:25505609

  4. A detachable mobile and adjustable telemetry system

    PubMed Central

    Parker, Tommy S; Persons, William E; Bradley, Joseph G; Gregg, Margaret; Gonzales, Shinelle K; Helton, Jesse S

    2013-01-01

    Many traditional mobile telemetry systems require permanently mounting a rod through the cabin of a vehicle to serve as the mast for a directional antenna. In this article we present an alternative to this configuration by providing a platform that can be placed atop the vehicle in which the antenna mast can be mounted and controlled from the cabin of the vehicle. Thereby making this design a viable option for researchers who share vehicles with others that may not approve of permanent vehicle modifications such as placing a hole in the roof of the vehicle as required by traditional mobile configurations. We tested the precision and accuracy of detachable mobile and adjustable telemetry system (DMATS) in an urban park with varying terrain, tree stands, overhead wires, and other structures that can contribute to signal deflection. We placed three radiocollars 50 m apart and 1.2 m above the ground then established three testing stations ∼280 m from the location of the radiocollars. The DMATS platform required 12 h for completion and cost $1059 USD. Four technicians were randomly assigned radio collars to triangulate using DMATS and a handheld telemetry system. We used a one-way analysis of variance (ANOVA) with a Scheffe post hoc test to compare error ellipses between azimuths taken using DMATS and the hand held system. Average error ellipses for all testers was 1.96 ± 1.22 ha. No significant differences were found between error ellipses of testers (P = 0.292). Our design, the DMATS, does not require any vehicle modification; thereby, making this a viable option for researchers sharing vehicles with others that may not approve of permanent vehicle alterations. PMID:23919133

  5. Carbon dioxide fixation by detached cereal caryopses

    SciTech Connect

    Watson, P.A.; Duffus, C.M. )

    1988-06-01

    Immature detached cereal caryposes from barley (Hordeum vulgare L. var distichum cv Midas) and wheat (Triticum aestivum L. cv Sicco) were shown to be capable of fixing externally supplied {sup 14}CO{sub 2} in the light or dark. Green cross cells and the testa contained the majority of the {sup 14}C-labeled material. Some {sup 14}C-labeled material was also found in the outer, or transparent, layer and in the endosperm/embryo fraction. More {sup 14}C was recovered from caryopses when they were incubated in {sup 14}CO{sub 2} without the transparent layer, thus suggesting that this layer is a barrier to the uptake of CO{sub 2}. In all cases, significant amounts of {sup 14}C-labeled material were found in caryopses after dark incubation with {sup 14}CO{sub 2}. Interestingly, CO{sub 2} fixation in the chlorophyll-less mutant Albino lemma was significantly greater in the light than in the dark. The results indicate that intact caryopses have the ability to translocate {sup 14}C-labeled assimilate derived from external CO{sub 2} to the endosperm/embryo. Carboxylating activity in the transparent layer appears to be confined to phosphoenolpyruvate carboxylase activity but that in the chloroplast-containing cross-cells may be accounted for by both ribulose-1,5-bisphosphate carboxylase-oxygenase and phosphoenolpyruvate carboxylase activity. Depending on a number of assumptions, the amount of CO{sub 2} fixed is sufficient to account for about 2% of the weight of starch found in the mature caryposis.

  6. Advantages of diabetic tractional retinal detachment repair

    PubMed Central

    Sternfeld, Amir; Axer-Siegel, Ruth; Stiebel-Kalish, Hadas; Weinberger, Dov; Ehrlich, Rita

    2015-01-01

    Purpose To evaluate the outcomes and complications of patients with diabetic tractional retinal detachment (TRD) treated with pars plana vitrectomy (PPV). Patients and methods We retrospectively studied a case series of 24 eyes of 21 patients at a single tertiary, university-affiliated medical center. A review was carried out on patients who underwent PPV for the management of TRD due to proliferative diabetic retinopathy from October 2011 to November 2013. Preoperative and final visual outcomes, intraoperative and postoperative complications, and medical background were evaluated. Results A 23 G instrumentation was used in 23 eyes (95.8%), and a 25 G instrumentation in one (4.2%). Mean postoperative follow-up time was 13.3 months (4–30 months). Visual acuity significantly improved from logarithm of the minimum angle of resolution (LogMAR) 1.48 to LogMAR 1.05 (P<0.05). Visual acuity improved by ≥3 lines in 75% of patients. Intraoperative complications included iatrogenic retinal breaks in seven eyes (22.9%) and vitreal hemorrhage in nine eyes (37.5%). In two eyes, one sclerotomy was enlarged to 20 G (8.3%). Postoperative complications included reoperation in five eyes (20.8%) due to persistent subretinal fluid (n=3), vitreous hemorrhage (n=1), and dislocated intraocular lens (n=1). Thirteen patients (54.2%) had postoperative vitreous hemorrhage that cleared spontaneously, five patients (20.8%) required antiglaucoma medications for increased intraocular pressure, seven patients (29.2%) developed an epiretinal membrane, and two patients (8.3%) developed a macular hole. Conclusion Patients with diabetic TRD can benefit from PPV surgery. Intraoperative and postoperative complications can be attributed to the complexity of this disease. PMID:26604667

  7. 4. VIEW OF COTTAGE NO. 8, SHOWING ORIGINAL SINGLECAR, DETACHED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. VIEW OF COTTAGE NO. 8, SHOWING ORIGINAL SINGLE-CAR, DETACHED GARAGE, LOOKING NORTH - Nine Mile Hydroelectric Development, Cottage No. 8, State Highway 291 along Spokane River, Nine Mile Falls, Spokane County, WA

  8. One- and two-photon detachment of O-

    NASA Astrophysics Data System (ADS)

    Génévriez, Matthieu; Urbain, Xavier; Dochain, Arnaud; Cyr, Alain; Dunseath, Kevin M.; Terao-Dunseath, Mariko

    2016-08-01

    Cross sections for one- and two-photon detachment of O-(1 s22 s22 p5P2o) have been determined in a joint experimental and theoretical study. The absolute measurement is based on the animated-crossed-beam technique, which is extended to the case of pulsed lasers, pulsed ion beams, and multiphoton detachment. The ab initio calculations employ R -matrix Floquet theory, with simple descriptions of the initial bound state and the residual oxygen atom which reproduce well the electron affinity and ground-state polarizability. For one-photon detachment, the measured and computed cross sections are in good mutual agreement, departing significantly from previous reference experiments and calculations. The generalized two-photon detachment cross section, measured at the Nd:YAG laser wavelength, is in good agreement with the R -matrix Floquet calculations. Long-standing discrepancies between theory and experiment are thus resolved.

  9. On Favorable Thermal Fields for Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Stelian, Carmen; Volz, Martin P.; Derby, Jeffrey J.

    2009-01-01

    The thermal fields of two Bridgman-like configurations, representative of real systems used in prior experiments for the detached growth of CdTe and Ge crystals, are studied. These detailed heat transfer computations are performed using the CrysMAS code and expand upon our previous analyses [14] that posited a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. Computational results indicate that heat transfer conditions that led to successful detached growth in both of these systems are in accordance with our prior assertion, namely that the prevention of crystal reattachment to the crucible wall requires the avoidance of any undercooling of the melt meniscus during the growth run. Significantly, relatively simple process modifications that promote favorable thermal conditions for detached growth may overcome detrimental factors associated with meniscus shape and crucible wetting. Thus, these ideas may be important to advance the practice of detached growth for many materials.

  10. Serous retinal detachment after trabeculectomy in angle recession glaucoma.

    PubMed

    Roy, Avik Kumar; Padhy, Debananda

    2015-01-01

    An 18-year-old male with 360 degree angle recession after blunt trauma in his right eye developed uncontrolled intraocular pressure (IOP) despite four antiglaucoma medications (AGM) with advancing disc damage. He underwent trabeculectomy with intraoperative mitomycin-c (MMC) application. There was an intraoperative vitreous prolapse which was managed accordingly. On post-surgery day 1, he had shallow choroidal detachment superiorly with non-recordable IOP. This was deteriorated 1 week postoperatively as choroidal detachment proceeded to serous retinal detachment. He was started with systemic steroid in addition to topical route. The serous effusions subsided within 2 weeks time. At the last follow up at 3 months, he was enjoying good visual acuity, deep anterior chamber, diffuse bleb, an IOP in low teens off any AGM and attached retina. This case highlights the rare occurrence of serous retinal detachment after surgical management of angle recession glaucoma.

  11. Bimatoprost Induced Serous Macular Detachment after Cataract Surgery

    PubMed Central

    Kaliaperumal, Subashini; Deb, Amit Kumar; Babu, K. Ramesh; Srinivasan, Renuka

    2016-01-01

    We report a case of bimatoprost induced serous macular detachment and choroidal folds following uneventful cataract surgery. A 66-year-old male using topical bimatoprost in both eyes for open angle glaucoma underwent uneventful cataract surgery in the right eye. Postoperatively, he was restarted on topical bimatoprost and antibiotic-steroids combination drops. One week after surgery, he presented with conjunctival hyperemia, serous macular detachment, and choroidal folds at the posterior pole. Fundus fluorescein angiography showed perifoveal leaks in early stage with pooling of dye in late stage. Discontinuation of bimatoprost led to resolution of serous detachment and choroidal folds within 3 weeks with significant improvement in visual acuity. Occurrence of serous macular detachment and choroidal folds in this case could be probably related to the proinflammatory property of bimatoprost. Hence, it should be used with caution in the immediate postoperative period after cataract surgery. PMID:27957367

  12. Inner detached frequency response curves: an experimental study

    NASA Astrophysics Data System (ADS)

    Gatti, Gianluca; Brennan, Michael J.

    2017-05-01

    Certain nonlinear vibrating systems have frequency response curves (FRCs), in which isolated detached curves exist inside the main continuous FRC. The behavior of these systems has hitherto been studied analytically and numerically, but to the authors' knowledge, there is no record of an inner detached FRC being detected experimentally. These curves may be hidden by numerical or experimental analysis, particularly when a system is subject to swept or stepped-sine excitation. Their existence may thus lead to unexpected dramatic changes in the amplitude of the system response. This paper presents an experimental study that involves the design, construction and testing of a specific system that has an isolated detached FRC inside the main continuous FRC. The experimental design of the test rig is supported by multibody dynamic simulations, and in the experimental tests the existence of a detached FRC was verified.

  13. Shock detachment process on cones in hypervelocity flows

    NASA Astrophysics Data System (ADS)

    Leyva, Ivett Alejandra

    1999-11-01

    The shock detachment process on cones in hypervelocity flows is one of the most sensitive flows to relaxation effects. The critical angle for shock detachment under frozen conditions can be very different from the critical angle under chemical and thermal equilibrium. The rate of increase of the detachment distance with cone angle is also affected by the relaxation rate. The purpose of this study is to explain the effects of nonequilibrium on the shock detachment distance and its growth rate on cones in hypervelocity flows. The study consists of an experimental and a computational program. The experimental part has been carried out at Caltech's hypervelocity reflected shock tunnel. Six free-stream conditions were chosen, using both N2 and CO2 as test gases. The experimental data obtained are holographic interferograms, surface temperature, and pressure measurements. The code employed for the numerical simulations is a Navier-Stokes solver that can account for thermal and chemical nonequilibrium in axisymmetric flows. The data obtained for the shock detachment distance confirms a previous theoretical model that predicts the detachment distance will grow more slowly for relaxing flows than for frozen or equilibrium flows. This difference is due to the behavior of the sonic line inside the shock layer. Different growth rates result when the detachment distance is controlled by the diameter of the cone (frozen and equilibrium cases) than when it is controlled by the relaxation length (nonequilibrium flows). The behavior of the detachment distance from the frozen to equilibrium limits for a given cone half-angle and free-stream condition has also been studied. It was confirmed that the ratio of the detachment distance to the cone diameter is constant in the two extremes and rapidly switches from one value to the other for cone diameters of about 2 cm to 16 cm. The experimental interferograms are also compared with numerical ones in terms of the detachment distance, the

  14. Scleral buckling for retinal detachment in patients with retinoblastoma

    SciTech Connect

    Buzney, S.M.; Pruett, R.C.; Regan, C.D.; Walton, D.S.; Smith, T.R.

    1984-10-15

    Three children (two girls and one boy) with bilateral retinoblastoma each developed a presumed rhegmatogenous retinal detachment in one eye. All three eyes had previously received radiation and cryotherapy. In each case the retinal detachment responded promptly to conventional surgical methods via scleral buckling in the area of treated retinoblastoma and presumed retinal break. All three eyes have retained useful vision for follow-up periods of 3.5 to 12 years.

  15. HAMLET Binding to α-Actinin Facilitates Tumor Cell Detachment

    PubMed Central

    Trulsson, Maria; Yu, Hao; Gisselsson, Lennart; Chao, Yinxia; Urbano, Alexander; Aits, Sonja; Mossberg, Ann-Kristin; Svanborg, Catharina

    2011-01-01

    Cell adhesion is tightly regulated by specific molecular interactions and detachment from the extracellular matrix modifies proliferation and survival. HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is a protein-lipid complex with tumoricidal activity that also triggers tumor cell detachment in vitro and in vivo, suggesting that molecular interactions defining detachment are perturbed in cancer cells. To identify such interactions, cell membrane extracts were used in Far-western blots and HAMLET was shown to bind α-actinins; major F-actin cross-linking proteins and focal adhesion constituents. Synthetic peptide mapping revealed that HAMLET binds to the N-terminal actin-binding domain as well as the integrin-binding domain of α-actinin-4. By co-immunoprecipitation of extracts from HAMLET-treated cancer cells, an interaction with α-actinin-1 and -4 was observed. Inhibition of α-actinin-1 and α-actinin-4 expression by siRNA transfection increased detachment, while α-actinin-4-GFP over-expression significantly delayed rounding up and detachment of tumor cells in response to HAMLET. In response to HAMLET, adherent tumor cells rounded up and detached, suggesting a loss of the actin cytoskeletal organization. These changes were accompanied by a reduction in β1 integrin staining and a decrease in FAK and ERK1/2 phosphorylation, consistent with a disruption of integrin-dependent cell adhesion signaling. Detachment per se did not increase cell death during the 22 hour experimental period, regardless of α-actinin-4 and α-actinin-1 expression levels but adherent cells with low α-actinin levels showed increased death in response to HAMLET. The results suggest that the interaction between HAMLET and α-actinins promotes tumor cell detachment. As α-actinins also associate with signaling molecules, cytoplasmic domains of transmembrane receptors and ion channels, additional α-actinin-dependent mechanisms are discussed. PMID:21408150

  16. HAMLET binding to α-actinin facilitates tumor cell detachment.

    PubMed

    Trulsson, Maria; Yu, Hao; Gisselsson, Lennart; Chao, Yinxia; Urbano, Alexander; Aits, Sonja; Mossberg, Ann-Kristin; Svanborg, Catharina

    2011-03-08

    Cell adhesion is tightly regulated by specific molecular interactions and detachment from the extracellular matrix modifies proliferation and survival. HAMLET (Human Alpha-lactalbumin Made LEthal to Tumor cells) is a protein-lipid complex with tumoricidal activity that also triggers tumor cell detachment in vitro and in vivo, suggesting that molecular interactions defining detachment are perturbed in cancer cells. To identify such interactions, cell membrane extracts were used in Far-western blots and HAMLET was shown to bind α-actinins; major F-actin cross-linking proteins and focal adhesion constituents. Synthetic peptide mapping revealed that HAMLET binds to the N-terminal actin-binding domain as well as the integrin-binding domain of α-actinin-4. By co-immunoprecipitation of extracts from HAMLET-treated cancer cells, an interaction with α-actinin-1 and -4 was observed. Inhibition of α-actinin-1 and α-actinin-4 expression by siRNA transfection increased detachment, while α-actinin-4-GFP over-expression significantly delayed rounding up and detachment of tumor cells in response to HAMLET. In response to HAMLET, adherent tumor cells rounded up and detached, suggesting a loss of the actin cytoskeletal organization. These changes were accompanied by a reduction in β1 integrin staining and a decrease in FAK and ERK1/2 phosphorylation, consistent with a disruption of integrin-dependent cell adhesion signaling. Detachment per se did not increase cell death during the 22 hour experimental period, regardless of α-actinin-4 and α-actinin-1 expression levels but adherent cells with low α-actinin levels showed increased death in response to HAMLET. The results suggest that the interaction between HAMLET and α-actinins promotes tumor cell detachment. As α-actinins also associate with signaling molecules, cytoplasmic domains of transmembrane receptors and ion channels, additional α-actinin-dependent mechanisms are discussed.

  17. Retinal Detachment due to CrossFit Training Injury

    PubMed Central

    Joondeph, Stephanie A.; Joondeph, Brian C.

    2013-01-01

    The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions. PMID:24106626

  18. Retinal Detachment due to CrossFit Training Injury.

    PubMed

    Joondeph, Stephanie A; Joondeph, Brian C

    2013-01-01

    The purpose of this paper is to describe a traumatic retinal detachment occurring as a result of CrossFit training using an elastic exercise band. The patient sustained an ocular injury from an elastic band during CrossFit training, resulting in a giant retinal dialysis and retinal detachment, which were successfully repaired. Trainers and athletes need to be aware of the potential for ocular injury from elastic exercise bands and take appropriate precautions.

  19. 1. Streetscape with south sides of Medical Detachment Barracks on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Streetscape with south sides of Medical Detachment Barracks on Ramp No. 5. Part of Building No. 9962-A with door is on far right. Also shown are the south A-sides of Buildings Nos. 9963, 9964, 9965, 9966, 9967 and 9968. The new Madigan Army Medical Center, which opened in 1992, is in far distance on right. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  20. 3. Streetscape showing north ends of Medical Detachment Barracks on ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. Streetscape showing north ends of Medical Detachment Barracks on Ramp No. 6. The 'triple-peak building' consists of Buildings Nos. 9973-B (far left), an addition (middle), and 9972-B (with covered walkway). Other buildings in distance are the north B sides of Building Nos. 9971, 9970 and 9969 (at far right). - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  1. [Vitreoretinal complications in cataract surgery. I. Retinal detachment].

    PubMed

    Hakenová, J; Rozsíval, P

    1997-12-01

    The authors investigate in a retrospective study complications of cataract operations which were performed in their department during the last 2.5 years by vitreoretinal surgery. They divided the operations into three basic groups: retinal detachment, luxation of the lens into the vitreous body and endophthalmitis. The largest group was formed by pseudophakic detachments--0.29% of operated cataracts. Luxation of the lens into the vitreous body and endophthalmitis treated by vitrectomy accounted for 0.06% each of operated cataracts. In the first part of the paper the authors analyze peroperative complications of cataract surgery, risk factors enhancing the risk of retinal detachment and evaluate anatomical and functional results of operations of pseudophakic retinal detachments. Peroperative rupture of the posterior capsule before cataract surgery was found in 63.6% of pseudophakic detachments, anterior vitrectomy was performed in 40%, YAG capsulotomy preceded the development of detachments in 13.3% of patients. The retina was applied in 76.4% of the eyes. Functional improvement was recorded in 65.8%, deterioration in 15.6% and an unaltered function after surgery was recorded in 18.6% eyes.

  2. Growth and Detachment of 5 Helix DNA Ribbons.

    PubMed

    Bashar, Saima; Hwang, Si Un; Lee, Junwye; Amin, Rashid; Dugasani, Sreekantha Reddy; Ha, Tai Hwan; Park, Sung Ha

    2016-04-01

    We report on the concentration-dependent surface-assisted growth and time-temperature-dependent detachment of one-dimensional 5 helix DNA ribbons (5HR) on a mica substrate. The growth coverage ratio was determined by varying the concentration of the 5HR strands in a test tube, and the detachment rate of 5HR on mica was determined by varying the incubation time at a fixed temperature on a heat block. The topological changes in the concentration-dependent attachment and the time-temperature-dependent detachment for 5HR on mica were observed via atomic force microscopy. The observations indicate that 5HR started to grow on mica at ~10 nM and provided full coverage at ~50 nM. In contrast, 5HR at 65 °C started to detach from mica after 5 min and was completely removed after 10 min. The growth and detachment coverage show a sinusoidal variation in the growth ratio and a linear variation with a rate of detachment of 20%/min, respectively. The physical parameters that control the stability of the DNA structures on a given substrate should be studied to successfully integrate DNA structures for physical and chemical applications.

  3. Defect Density Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Cobb, S. D.; Volz, M. P.; Szoke, J.; Szofran, F. R.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several (111)-oriented, Ga-doped germanium crystals were grown in pyrolytic boron nitride (pBN) containers by the Bridgman and the detached Bridgman growth techniques. Growth experiments in closed-bottom pBN containers resulted in nearly completely detached-grown crystals, because the gas pressure below the melt can build up to a higher pressure than above the melt. With open-bottom tubes the gas pressure above and below the melt is balanced during the experiment, and thus no additional force supports the detachment. In this case the crystals grew attached to the wall. Etch pit density (EPD) measurements along the axial growth direction indicated a strong improvement of the crystal quality of the detached-grown samples compared to the attached samples. Starting in the seed with an EPD of 6-8 x 10(exp 3)/square cm it decreased in the detached-grown crystals continuously to about 200-500/square cm . No significant radial difference between the EPD on the edge and the middle of the crystal exists. In the attached grown samples the EPD increases up to a value of about 2-4 x 10(exp 4)/square cm (near the edge) and up to 1 x 10(exp 4)/square cm in the middle of the sample. Thus the difference between the detached- and the attached-grown crystals with respect to the EPD is approximately two orders of magnitude.

  4. Effects of Nanoscale Surface Roughness on Colloid Detachment

    NASA Astrophysics Data System (ADS)

    Rasmuson, J. A.; Johnson, W. P.

    2015-12-01

    Recent advances in colloid transport science have demonstrated the importance of surface roughness on colloid attachment; however, few studies have investigated the influence of nano-scale roughness on colloid detachment. This study explores the effects of flow perturbations on a variety of mineral surfaces, as well as NaOH treated (i.e. rough, Figure 1a) and untreated (i.e. smooth, Figure 1b) surfaces for colloids of various sizes attached in an impinging jet system under flowing and stagnant conditions. These experiments showed minimal detachment from the roughened surfaces (treated glass) and significant detachment from the smooth surfaces (untreated glass and mica). A correlation between residence time and attachment irreversibility was also revealed, indicating that the particles that spent the longest time attached to the surface developed the strongest adhesion. The representative surface-heterogeneity model developed by Pazmino et al. (2014) was used to conduct detachment simulations under similar geochemical and flow conditions. While simulated results show qualitative agreement with experimental results, they tend to over-predict detachment, highlighting differences among simulated versus real surfaces, which may be related to surface roughness. These results suggest that more sophisticated models that incorporate surface roughness and time-based adhesion are needed to accurately predict colloid detachment in environmental systems.

  5. Defect Density Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Cobb, S. D.; Volz, M. P.; Szoke, J.; Szofran, F. R.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Several (111)-oriented, Ga-doped germanium crystals were grown in pyrolytic boron nitride (pBN) containers by the Bridgman and the detached Bridgman growth techniques. Growth experiments in closed-bottom pBN containers resulted in nearly completely detached-grown crystals, because the gas pressure below the melt can build up to a higher pressure than above the melt. With open-bottom tubes the gas pressure above and below the melt is balanced during the experiment, and thus no additional force supports the detachment. In this case the crystals grew attached to the wall. Etch pit density (EPD) measurements along the axial growth direction indicated a strong improvement of the crystal quality of the detached-grown samples compared to the attached samples. Starting in the seed with an EPD of 6-8 x 10(exp 3)/square cm it decreased in the detached-grown crystals continuously to about 200-500/square cm . No significant radial difference between the EPD on the edge and the middle of the crystal exists. In the attached grown samples the EPD increases up to a value of about 2-4 x 10(exp 4)/square cm (near the edge) and up to 1 x 10(exp 4)/square cm in the middle of the sample. Thus the difference between the detached- and the attached-grown crystals with respect to the EPD is approximately two orders of magnitude.

  6. Improved Crystal Quality By Detached Solidification in Microgravity

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Wang, Yaz-Hen; Wang, Jian-Bin

    2003-01-01

    Many microgravity directional solidification experiments yielded ingots with portions that grew without contacting the ampoule wall, leading to greatly improved crystallographic perfection. Our long term goals have been: (1) To develop a complete understanding of all of the phenomena of detached solidification.; (2) To make it possible to achieve detached solidification reproducibly; (3) To increase crystallographic perfection through detached solidification. We have three major achievements to report here: (1) We obtained a new material balance solution for the Moving Meniscus Model of detached solidification. This solution greatly clarifies the physics as well as the roles of the parameters in the system; (2) We achieved detached solidification of InSb growing on earth in BN-coated ampoules; (3) We performed an extensive series of experiments on freezing water that showed how to form multiple gas bubbles or tubes on the ampoule wall. However, these did not propagate around the wall and lead to fully detached solidification unless the ampoule wall was extremely rough and non-wetted.

  7. Association between oral fluoroquinolone use and retinal detachment.

    PubMed

    Pasternak, Björn; Svanström, Henrik; Melbye, Mads; Hviid, Anders

    2013-11-27

    A recent study of ophthalmologic patients found a strong association between fluoroquinolone use and retinal detachment. Given the prevalent use of fluoroquinolones, this could, if confirmed in the general population, translate to many excess cases of retinal detachment that are potentially preventable. To investigate if oral fluoroquinolone use is associated with an increased risk of retinal detachment. A nationwide, register-based cohort study in Denmark from 1997 through 2011, using linked data on participant characteristics, filled prescriptions, and cases of retinal detachment with surgical treatment (scleral buckling, vitrectomy, or pneumatic retinopexy). The cohort included 748,792 episodes of fluoroquinolone use (660,572 [88%] ciprofloxacin) and 5,520,446 control episodes of nonuse. Poisson regression was used to estimate rate ratios (RRs) for incident retinal detachment, adjusting for a propensity score that included a total of 21 variables. The risk windows were classified as current use (days 1-10 from start of treatment), recent use (days 11-30), past use (days 31-60), and distant use (days 61-180). A total of 566 cases of retinal detachment occurred, of which 465 (82%) were rhegmatogenous detachments; 72 in fluoroquinolone users and 494 in control nonusers. The crude incidence rate was 25.3 cases per 100,000 person-years in current users, 18.9 in recent users, 26.8 in past users, and 24.8 in distant users compared with 19.0 in nonusers. Compared with nonuse, fluoroquinolone use was not associated with a significantly increased risk of retinal detachment: the adjusted RRs were 1.29 (95% CI, 0.53 to 3.13) for current use; 0.97 (95% CI, 0.46 to 2.05) for recent use; 1.37 (95% CI, 0.80 to 2.35) for past use; and 1.27 (95% CI, 0.93 to 1.75) for distant use. The absolute risk difference, estimated as the adjusted number of retinal detachment cases per 1,000,000 treatment episodes, was 1.5 (95% CI, -2.4 to 11.1) for current use. In this cohort study based on

  8. An aluminum-based rat model for Alzheimer's disease exhibits oxidative damage, inhibition of PP2A activity, hyperphosphorylated tau, and granulovacuolar degeneration.

    PubMed

    Walton, J R

    2007-09-01

    In Alzheimer's disease (AD), oxidative damage leads to the formation of amyloid plaques while low PP2A activity results in hyperphosphorylated tau that polymerizes to form neurofibrillary tangles. We probed these early events, using brain tissue from a rat model for AD that develops memory deterioration and AD-like behaviors in old age after chronically ingesting 1.6 mg aluminum/kg bodyweight/day, equivalent to the high end of the human dietary aluminum range. A control group consumed 0.4 mg aluminum/kg/day. We stained brain sections from the cognitively-damaged rats for evidence of amyloid plaques, neurofibrillary tangles, aluminum, oxidative damage, and hyperphosphorylated tau. PP2A activity levels measured 238.71+/-17.56 pmol P(i)/microg protein and 580.67+/-111.70 pmol P(i)/microg protein (p<0.05) in neocortical/limbic homogenates prepared from cognitively-damaged and control rat brains, respectively. Thus, PP2A activity in cognitively-damaged brains was 41% of control value. Staining results showed: (1) aluminum-loading occurs in some aged rat neurons as in some aged human neurons; (2) aluminum-loading in rat neurons is accompanied by oxidative damage, hyperphosphorylated tau, neuropil threads, and granulovacuolar degeneration; and (3) amyloid plaques and neurofibrillary tangles were absent from all rat brain sections examined. Known species difference can reasonably explain why plaques and tangles are unable to form in brains of genetically-normal rats despite developing the same pathological changes that lead to their formation in human brain. As neuronal aluminum can account for early stages of plaque and tangle formation in an animal model for AD, neuronal aluminum could also initiate plaque and tangle formation in humans with AD.

  9. Decrease in age-related tau hyperphosphorylation and cognitive improvement following vitamin D supplementation are associated with modulation of brain energy metabolism and redox state.

    PubMed

    Briones, T L; Darwish, H

    2014-03-14

    In the present study we examined whether vitamin D supplementation can reduce age-related tau hyperphosphorylation and cognitive impairment by enhancing brain energy homeostasis and protein phosphatase 2A (PP2A) activity, and modulating the redox state. Male F344 rats aged 20 months (aged) and 6 months (young) were randomly assigned to either vitamin D supplementation or no supplementation (control). Rats were housed in pairs and the supplementation group (n=10 young and n=10 aged) received subcutaneous injections of vitamin D (1, α25-dihydroxyvitamin D3) for 21 days. Control animals (n=10 young and n=10 aged) received equal volume of normal saline and behavioral testing in the water maze started on day 14 after the initiation of vitamin D supplementation. Tau phosphorylation, markers of brain energy metabolism (ADP/ATP ratio and adenosine monophosphate-activated protein kinase) and redox state (levels of reactive oxygen species, activity of superoxide dismutase, and glutathione levels) as well as PP2A activity were measured in hippocampal tissues. Our results extended previous findings that: (1) tau phosphorylation significantly increased during aging; (2) markers of brain energy metabolism and redox state are significantly decreased in aging; and (3) aged rats demonstrated significant learning and memory impairment. More importantly, we found that age-related changes in brain energy metabolism, redox state, and cognitive function were attenuated by vitamin D supplementation. No significant differences were seen in tau hyperphosphorylation, markers of energy metabolism and redox state in the young animal groups. Our data suggest that vitamin D ameliorated the age-related tau hyperphosphorylation and cognitive decline by enhancing brain energy metabolism, redox state, and PP2A activity making it a potentially useful therapeutic option to alleviate the effects of aging. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Bilateral choroidal detachment with exudative retinal detachment in a patient with septicaemia.

    PubMed

    Rani, Padmaja Kumari; Ambiya, Vikas; Senthil, Sirisha; Jalali, Subhadra

    2016-12-20

    We present a case of bilateral choroidal and exudative retinal detachment with hypotony in a patient with septicaemia. Our patient after initial hospitalisation was treated by the local ophthalmologist as a case of sterile pan uveitis with systemic and topical steroids that did not have any effect. Our patient responded well to timely surgical intervention of choroidal drainage and vitrectomy with silicone oil tamponade followed by steroids and antibiotics. Cataract progression in both eyes occurred due to hypotony, inflammation, use of steroids and the vitreous surgery. It was successfully managed with timely surgical removal of cataract and intraocular lens implantation in both eyes facilitating early visual rehabilitation. Topical medications included frequent topical steroids and antibiotics as per our published protocols. 2016 BMJ Publishing Group Ltd.

  11. Effect of treadmill exercise on PI3K/AKT/mTOR, autophagy, and Tau hyperphosphorylation in the cerebral cortex of NSE/htau23 transgenic mice

    PubMed Central

    Kang, Eun-Bum; Cho, Joon-Yong

    2015-01-01

    Purpose Neurofibrillary tangles, one of pathological features of Alzheimer’s disease, are produced by the hyperphosphorylation and aggregation of tau protein. This study aimed to investigate the effects of treadmill exercise on PI3K/AKT/mTOR signal transmission, autophagy, and cognitive ability that are involved in the hyperphosphorylation and aggregation of tau protein. Methods Experimental animals (NSE/htau23 mice) were divided into non-transgenic control group (Non-Tg-Control; CON; n = 7), transgenic control group (Tg-CON; n = 7), and transgenic exercise group (Tg-Treadmill Exercise; TE; n = 7). The Tg-TE group was subjected to treadmill exercise for 12 weeks. After the treadmill exercise was completed, the cognitive ability was determined by conducting underwater maze tests. Western blot was conducted to determine the phosphorylation status of PI3K/AKT/mTOR proteins and autophagy-related proteins (Beclin-1, p62, LC3-B); hyperphosphorylation and aggregation of tau protein (Ser199/202, Ser404, Thr231, PHF-1); and phosphorylation of GSK-3β, which is involved in the phosphorylation of tau protein in the cerebral cortex of experimental animals. Results In the Tg-TE group that was subjected to treadmill exercise for 12 weeks, abnormal mTOR phosphorylation of PI3K/AKT proteins was improved via increased phosphorylation and its activity was inhibited by increased GSK-3β phosphorylation compared with those in the Tg-CON group, which was used as the control group. In addition, the expression of Beclin-1 protein involved in autophagosome formation was increased in the Tg-TE group compared with that in the Tg-CON group, whereas that of p62 protein was reduced in the Tg-TE group compared with that in the Tg-CON group. Autophagy was activated owing to the increased expression of LC3-B that controls the completion of autophagosome formation. The hyperphosphorylation and aggregation (Ser199/202, Ser404, Thr231, PHF-1) of tau protein was found to be reduced in the Tg

  12. A Chick Model of Retinal Detachment: Cone Rich and Novel

    PubMed Central

    Cebulla, Colleen M.; Zelinka, Chris P.; Scott, Melissa A.; Lubow, Martin; Bingham, Amanda; Rasiah, Stephen; Mahmoud, Ashraf M.; Fischer, Andy J.

    2012-01-01

    Background Development of retinal detachment models in small animals can be difficult and expensive. Here we create and characterize a novel, cone-rich retinal detachment (RD) model in the chick. Methodology/Principal Findings Retinal detachments were created in chicks between postnatal days 7 and 21 by subretinal injections of either saline (SA) or hyaluronic acid (HA). Injections were performed through a dilated pupil with observation via surgical microscope, using the fellow eye as a control. Immunohistochemical analyses were performed at days 1, 3, 7, 10 and 14 after retinal detachment to evaluate the cellular responses of photoreceptors, Müller glia, microglia and nonastrocytic inner retinal glia (NIRG). Cell proliferation was detected with bromodeoxyuridine (BrdU)-incorporation and by the expression of proliferating cell nuclear antigen (PCNA). Cell death was detected with terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL). As in mammalian models of RD, there is shortening of photoreceptor outer segments and mis-trafficking of photoreceptor opsins in areas of RD. Photoreceptor cell death was maximal 1 day after RD, but continued until 14 days after RD. Müller glia up-regulated glial fibriliary acidic protein (GFAP), proliferated, showed interkinetic nuclear migration, and migrated to the subretinal space in areas of detachment. Microglia became reactive; they up-regulated CD45, acquired amoeboid morphology, and migrated toward outer retina in areas of RD. Reactive NIRG cells accumulated in detached areas. Conclusions/Significance Subretinal injections of SA or HA in the chick eye successfully produced retinal detachments and cellular responses similar to those seen in standard mammalian models. Given the relatively large eye size, and considering the low cost, the chick model of RD offers advantages for high-throughput studies. PMID:22970190

  13. Detachment folding, fold amplification, and diapirism in thrust wedge experiments

    NASA Astrophysics Data System (ADS)

    Bonini, Marco

    2003-12-01

    The relations between detachment folding, fold amplification, and salt diapirism in contractional settings have been investigated by means of scaled analogue models. The viscosity of the silicone layer simulating salt in nature and the shortening rates were combined in order to reproduce weak (type 1 models) and strong (type 2 models) décollements. Deformation patterns in the roof sequence exhibited two contrasting styles, (1) outward propagation of detachment folding along the décollement (OFP mode) and (2) passive roof duplex (PRD mode). In type 2 models, detachment folding propagated away from the most external thrust in the floor sequence, while in type 1 models, long-lived detachment folds almost invariably localized amplified above a floor thrust tip as a result of strain localization. A silicone wall intruded occasionally into the crestal graben of detachment folds in type 1 and OFP models. Best fitting of transition models data points indicates nonlinear relations with regression curves close to the equilateral hyperbola equation for both OFP-PRD and amplified detachment folds-box folds transitions. A quantitative comparison of model results with nature has been attempted by plotting salt-based fold-and-thrust belts data points on the scaled transition curves obtained from the modeling. Such a comparison relates shear stress products and ratios to the conditions favoring the amplification of detachment folds and the potential emplacement of ductile diapirs in their core. By reducing the roof sequence strength, pore fluid pressure λb is inferred to shift the equilibrium of fold-and-thrust belts toward the field of OFP and diapirism.

  14. Origin of metamorphic core complexes and detachment faults

    NASA Astrophysics Data System (ADS)

    Wu, G.; Lavier, L. L.

    2013-12-01

    Origin of metamorphic core complexes and detachment faults Guangliang Wu1,2, Luc L. Lavier1,2 1 Institute for Geophysics, University of Texas at Austin, TX 78758, USA 2 Department of Geological Sciences, University of Texas at Austin, TX 78712, USA Metamorphic core complexes (MCCs) and detachment faults are widely observed in collapsing orogens, such as Western US Cordillera, the Aegean and Papua New Guinea. A theory for the origin of MCCs has to provide: i) a viable mechanism to bring deeper crustal material to the surface, ii) a scenario that allows slip on low-angle detachment faults, and iii) a viable mechanism to form a flat Moho at a certain stage of evolution. However, previous models ignored at least one of these three requirements. Using thermo-mechanical models constrained by geological and geophysical observation, we simulated MCCs and detachment faults in the context of collapsing orogens with preexisting shear zones and middle crust of variable strength. We found that MCCs and detachment faults are natural products of gravity driven middle crustal extrusion and exhumation and strong crustal decoupling along the preexisting shear zones in a favorable state of stress in collapsing orogens. Based on previous geological and geophysical observations and our numerical simulations, we categorized MCCs into four types: i) massifs, such as Menderes massif and SW Rhodope massif, ii) single large asymmetric MCC (classic MCC), such as Whipple mountains and Snake Range Mountains, Western US Cordillera and Crete and Cyclades, the Aegean, iii) multiple less evolved MCCs, such as Black Mountains turtlebacks, and iv) subsurface ';MCC', such as interpreted at the Adriatic coast. We also recognized two types of detachment faults: one being listric fault transitioning to a convex upward shear zone at greater depth and the other a shallow exhumed upward convex shear zone. Our new models successfully predict many MCCs and detachment faults known to date.

  15. Mesospheric electron detachment and LORE recovery times

    NASA Astrophysics Data System (ADS)

    Gordillo-Vazquez, Francisco J.; Haldoupis, Christos; Luque, Alejandro

    2015-04-01

    We present new results concerning the recovery times (> 10 minutes) of LOng Recovery Early VLF events (LORE) in the upper mesosphere connected to electromagnetic pulses (EMP) of large (> 250 kA km) charge moment change (CMC) ± CG (cloud to ground) lightning capable of producing elves or elve-sprite pairs (in the case of +CG parent lightning) [1], [2]. We have modeled two possible scenarios considering first the relaxation of slightly perturbed ambient electron densities (ne0 + Δne) without an impulsive ionization source and another scenario where the ambient electron density is considerably enhanced due to an impulsive ionization source (the lightning EMP). The full non-equilibrium kinetic and 2D EMP modelling of the perturbed mesosphere in the 76 km - 92 km range during LORE occurring conditions indicates that the electron density relaxation time (defined as the time the perturbed electron density, Δne, takes to decay a factor 1/e of the way to the ambient electron density (ne0)) is critically controlled at each altitude by the relative importance of associative detachment (of O- by, respectively, O and CO and of O2- by O) with respect to electron loss mechanisms (mainly 3-body, 2-body attachment and electron-ion recombination at the highest altitudes). We found that the maximum electron density relaxation time (> 15000 s) occur between 80 km and 82 km while it decreases with increasing altitudes to 12000 s (at 85 km) and about 2000 s (at 92 km). However, LORES are presumably due to VLF scattering from electron density enhancements caused by lightning-induced EMPs in the uppermost D region ionosphere (85 - 92 km). Thus the observed VLF signal recoveries (LORE recovery times) should associate with the relaxation of the maximum enhanced electron densities produced by elves between 85 km and 92 km [3]. Finally, our results for the lowest altitudes considered (76 km and 77 km) are in good agreement with the recovery times (between 20 s and 120 s) of the typical

  16. Miocene detachment faulting predating EPR propagation: Southern Baja California

    NASA Astrophysics Data System (ADS)

    Bot, Anna; Geoffroy, Laurent; Authemayou, Christine; Bellon, Hervé; Graindorge, David; Pik, Raphaël.

    2016-05-01

    At the southern tip of the Baja California peninsula, we characterize the onshore structures and kinematics associated with crustal necking leading up to the Pliocene breakup and early East Pacific Rise seafloor spreading. From a combination of tectonic field investigations, K-Ar and cosmogenic isotope dating and geomorphology, we propose that the Los Cabos block represents the exhumed footwall of a major detachment fault. This north trending detachment fault is marked by a conspicuous low-dipping brittle-ductile shear zone showing a finite displacement with top to the SE ending to the ESE. This major feature is associated with fluid circulations which led to rejuvenation of the deformed Cretaceous magmatic rocks at a maximum of 17.5 Ma. The detachment footwall displays kilometer-scale corrugations controlling the present-day drainage pattern. This major detachment is synchronous with the development of the San José del Cabo Basin where syntectonic sedimentation took place from the middle Miocene to probably the early Pliocene. We propose that this seaward dipping detachment fault accommodates the proximal crustal necking of the Baja California passive margin, which predates the onset of formation of the East Pacific Rise spreading axis in the Cabo-Puerto Vallarta segment. Our data illustrate an apparent anticlockwise rotation of the stretching direction in Baja California Sur from ~17 Ma to the Pliocene.

  17. Numerical Investigation of Plasma Detachment in Magnetic Nozzle Experiments

    NASA Technical Reports Server (NTRS)

    Sankaran, Kamesh; Polzin, Kurt A.

    2008-01-01

    At present there exists no generally accepted theoretical model that provides a consistent physical explanation of plasma detachment from an externally-imposed magnetic nozzle. To make progress towards that end, simulation of plasma flow in the magnetic nozzle of an arcjet experiment is performed using a multidimensional numerical simulation tool that includes theoretical models of the various dispersive and dissipative processes present in the plasma. This is an extension of the simulation tool employed in previous work by Sankaran et al. The aim is to compare the computational results with various proposed magnetic nozzle detachment theories to develop an understanding of the physical mechanisms that cause detachment. An applied magnetic field topology is obtained using a magnetostatic field solver (see Fig. I), and this field is superimposed on the time-dependent magnetic field induced in the plasma to provide a self-consistent field description. The applied magnetic field and model geometry match those found in experiments by Kuriki and Okada. This geometry is modeled because there is a substantial amount of experimental data that can be compared to the computational results, allowing for validation of the model. In addition, comparison of the simulation results with the experimentally obtained plasma parameters will provide insight into the mechanisms that lead to plasma detachment, revealing how they scale with different input parameters. Further studies will focus on modeling literature experiments both for the purpose of additional code validation and to extract physical insight regarding the mechanisms driving detachment.

  18. Bilateral patching in retinal detachment: fluid mechanics and retinal "settling".

    PubMed

    Foster, William J

    2011-07-20

    When a patient suffers a retinal detachment and surgery is delayed, it is known clinically that bilaterally patching the patient may allow the retina to partially reattach or "settle." Although this procedure has been performed since the 1860s, there is still debate as to how such a maneuver facilitates the reattachment of the retina. Finite element calculations using commercially available analysis software are used to elucidate the influence of reduction in eye movement caused by bilateral patching on the flow of subretinal fluid in a physical model of retinal detachment. It was found that by coupling fluid mechanics with structural mechanics, a physically consistent explanation of increased retinal detachment with eye movements can be found in the case of traction on the retinal hole. Large eye movements increase vitreous traction and detachment forces on the edge of the retinal hole, creating a subretinal vacuum and facilitating increased subretinal fluid. Alternative models, in which intraocular fluid flow is redirected into the subretinal space, are not consistent with these simulations. The results of these simulations explain the physical principles behind bilateral patching and provide insight that can be used clinically. In particular, as is known clinically, bilateral patching may facilitate a decrease in the height of a retinal detachment. The results described here provide a description of a physical mechanism underlying this technique. The findings of this study may aid in deciding whether to bilaterally patch patients and in counseling patients on pre- and postoperative care.

  19. Protein interaction module-assisted function X (PIMAX) approach to producing challenging proteins including hyperphosphorylated tau and active CDK5/p25 kinase complex.

    PubMed

    Sui, Dexin; Xu, Xinjing; Ye, Xuemei; Liu, Mengyu; Mianecki, Maxwell; Rattanasinchai, Chotirat; Buehl, Christopher; Deng, Xiexiong; Kuo, Min-Hao

    2015-01-01

    Many biomedically critical proteins are underrepresented in proteomics and biochemical studies because of the difficulty of their production in Escherichia coli. These proteins might possess posttranslational modifications vital to their functions, tend to misfold and be partitioned into bacterial inclusion bodies, or act only in a stoichiometric dimeric complex. Successful production of these proteins requires efficient interaction between these proteins and a specific "facilitator," such as a protein-modifying enzyme, a molecular chaperone, or a natural physical partner within the dimeric complex. Here we report the design and application of a protein interaction module-assisted function X (PIMAX) system that effectively overcomes these hurdles. By fusing two proteins of interest to a pair of well-studied protein-protein interaction modules, we were able to potentiate the association of these two proteins, resulting in successful production of an enzymatically active cyclin-dependent kinase complex and hyperphosphorylated tau protein, which is intimately linked to Alzheimer disease. Furthermore, using tau isoforms quantitatively phosphorylated by GSK-3β and CDK5 kinases via PIMAX, we demonstrated the hyperphosphorylation-stimulated tau oligomerization in vitro, paving the way for new Alzheimer disease drug discoveries. Vectors for PIMAX can be easily modified to meet the needs of different applications. This approach thus provides a convenient and modular suite with broad implications for proteomics and biomedical research.

  20. Liraglutide Improves Water Maze Learning and Memory Performance While Reduces Hyperphosphorylation of Tau and Neurofilaments in APP/PS1/Tau Triple Transgenic Mice.

    PubMed

    Chen, Shuyi; Sun, Jie; Zhao, Gang; Guo, Ai; Chen, Yanlin; Fu, Rongxia; Deng, Yanqiu

    2017-04-06

    The purpose of this study was to explore how liraglutide affects AD-like pathology and cognitive function in APP/PS1/Tau triple transgenic (3 × Tg) Alzheimer disease (AD) model mice. Male 3 × Tg mice and C57BL/6 J mice were treated for 8 weeks with liraglutide (300 μg/kg/day, subcutaneous injection) or saline. Levels of phosphorylated tau, neurofilaments (NFs), extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) in brain tissues were assessed with western blots. Fluoro-Jade-B labeling were applied to detect pathological changes. The Morris water maze (MWM) was used to assess the spatial learning and memory. Liraglutide decreased levels of hyperphosphorylated tau and NFs in 3 × Tg liraglutide-treated (Tg + LIR) mice, increased ERK phosphorylation, and decreased JNK phosphorylation. Liraglutide also decreased the number of degenerative neurons in the hippocampus and cortex of Tg + LIR mice, and shortened their escape latencies and increased their hidden platform crossings in the MWM task. Liraglutide did not significantly affect the animals' body weight (BW) or fasting blood glucose. Liraglutide can reduce hyperphosphorylation of tau and NFs and reduce neuronal degeneration, apparently through alterations in JNK and ERK signaling, which may be related to its positive effects on AD-like learning and memory impairment.

  1. Targeted Downregulation of dMyc Suppresses Pathogenesis of Human Neuronal Tauopathies in Drosophila by Limiting Heterochromatin Relaxation and Tau Hyperphosphorylation.

    PubMed

    Chanu, Soram Idiyasan; Sarkar, Surajit

    2017-05-01

    Human tauopathies such as Alzheimer's Disease (AD), frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17), Pick's disease etc., are a group of neurodegenerative diseases which are characterized by abnormal hyperphosphorylation of tau that leads to formation of neurofibrillary tangles. Recapitulating several features of human neurodegenerative disorders, the Drosophila tauopathy model displays compromised lifespan, locomotor function impairment, and brain vacuolization in adult brain which is progressive and age dependent. Here, we demonstrate that tissue-specific downregulation of the Drosophila homolog of human c-myc proto-oncogene (dMyc) suppresses tau-mediated morphological and functional deficits by reducing abnormal tau hyperphosphorylation and restoring the heterochromatin loss. Our studies show for the first time that the inherent chromatin remodeling ability of myc proto-oncogenes could be exploited to limit the pathogenesis of human neuronal tauopathies in the Drosophila disease model. Interestingly, recent reports on successful uses of some anti-cancer drugs against Alzheimer's and Parkinson's diseases in clinical trials and animal models strongly support our findings and proposed possibility.

  2. Paleostress analyses in the uppermost footwalls of the Whipple detachment and the West Salton detachment faults, southern California

    NASA Astrophysics Data System (ADS)

    Luther, A. L.; Axen, G. J.; Selverstone, J.; Michelsen, K. J.

    2010-12-01

    Low-angle normal faults (LANFs) slip while nearly perpendicular to the regional S1, presenting a mechanical paradox that may be explained by rotation of S1 toward the fault as it is approached, weak materials reducing friction and/or high pore-fluid pressure. Well-exposed LANF footwalls provide opportunities for detailed studies of weak faults. Paleostress inversions of fault-slip data coupled with structural and chemical analyses of footwall rocks are in progress on the Whipple detachment fault (WDF; >40 km Miocene slip; evolved from ductile shear zone to brittle fault) and the West Salton detachment fault (WSDF; ~10 km slip during dextral-wrench tectonism coeval with San Andreas Fault slip). Both were folding during detachment slip. Paleostress analyses indicate that both faults slipped mainly in extensional stress fields (sub-vertical S1) and in axial compression (S2 ≈ S3). Over 40% of extensional stress fields yield S1 plunging >70° relative to the detachment, but ~30% yield plunges of 40° to 60° relative to the detachment. Thus, the stress field may have been locally and/or temporarily rotated away from sub-vertical during detachment slip. About 15% of the inversions yield shortening stress fields (S1 ~horizontal) consistent with folding and/or dextral-wrench deformation. Mutually cross-cutting relationships between fracture sets suggest that the stress fields may have alternated through time. “Mini-detachments” (MDs) are small, detachment-parallel faults that are structurally analogous to the main faults. Inversions yield S1 ~45° from the MDs and a larger magnitude of S2 relative to S3. Damage zones subjacent to MD fault cores commonly yield more moderately plunging S1 than do MD fault cores or deeper rocks. Petrological evidence suggests that the MDs formed early in the detachment history (Selverstone et al., GSA Abstract, 2009). If their damage zones also formed early, then S1 may have been shallower early in detachment history and(or) at greater

  3. Strategy for the management of complex retinal detachments: the European vitreo-retinal society retinal detachment study report 2.

    PubMed

    Adelman, Ron A; Parnes, Aaron J; Sipperley, Jack O; Ducournau, Didier

    2013-09-01

    To study the outcome of the treatment of complex rhegmatogenous retinal detachments (RRDs). Nonrandomized, multicenter, retrospective study. One hundred seventy-six surgeons from 48 countries spanning 5 continents reported primary procedures for 7678 RRDs. Reported data included clinical manifestations, the method of repair, and the outcome. Failure of retinal detachment repair (level 1 failure rate), remaining silicone oil at the study's conclusion (level 2 failure rate), and need for additional procedures to repair the detachments (level 3 failure rate). The main categories of complex retinal detachments evaluated in this investigation were: (1) grade B proliferative vitreoretinopathy (PVR; n = 917), (2) grade C-1 PVR (n = 637), (3) choroidal detachment or significant hypotony (n = 578), (4) large or giant retinal tears (n = 1167), and (5) macular holes (n = 153). In grade B PVR, the level 1 failure rate was higher when treated with a scleral buckle alone versus vitrectomy (P = 0.0017). In grade C-1 PVR, there was no statistically significant difference in the level 1 failure rate between those treated with vitrectomy, with or without scleral buckle, and those treated with scleral buckle alone (P = 0.7). Vitrectomy with a supplemental buckle had an increased failure rate compared with those who did not receive a buckle (P = 0.007). There was no statistically significant difference in level 1 failure rate between tamponade with gas versus silicone oil in patients with grade B or C-1 PVR. Cases with choroidal detachment or hypotony treated with vitrectomy had a significantly lower failure rate versus treatment with scleral buckle alone (P = 0.0015). Large or giant retinal tears treated with vitrectomy also had a significantly lower failure rate versus treatment with scleral buckle (P = 7×10(-8)). In patients with retinal detachment, when choroidal detachment, hypotony, a large tear, or a giant tear is present, vitrectomy is the procedure of choice. In retinal

  4. Streetscape showing north sides of five of eight Medical Detachment ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Streetscape showing north sides of five of eight Medical Detachment Barracks on Ramp No. 5. Note that Building No. 9966-B on right has a wooden frame sun porch. This Standard Ward construction is different than most of the other Medical Detachment Barracks, which are all- brick. On the opposite side of this building, the construction is all-brick (Building No. 9966-A, not shown). Buildings No. 9967-B and 9968-B (not shown) also have wooden frame sun porches. Other buildings in photo are, on right, the north B-sides of Buildings Nos. 9965, 9964, 9963 and 9962. On left is Building No. 9971-A on Ramp No. 6. Corridor A is visible in far distance. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  5. Detachment energies of spheroidal particles from fluid-fluid interfaces

    NASA Astrophysics Data System (ADS)

    Davies, Gary B.; Krüger, Timm; Coveney, Peter V.; Harting, Jens

    2014-10-01

    The energy required to detach a single particle from a fluid-fluid interface is an important parameter for designing certain soft materials, for example, emulsions stabilised by colloidal particles, colloidosomes designed for targeted drug delivery, and bio-sensors composed of magnetic particles adsorbed at interfaces. For a fixed particle volume, prolate and oblate spheroids attach more strongly to interfaces because they have larger particle-interface areas. Calculating the detachment energy of spheroids necessitates the difficult measurement of particle-liquid surface tensions, in contrast with spheres, where the contact angle suffices. We develop a simplified detachment energy model for spheroids which depends only on the particle aspect ratio and the height of the particle centre of mass above the fluid-fluid interface. We use lattice Boltzmann simulations to validate the model and provide quantitative evidence that the approach can be applied to simulate particle-stabilized emulsions, and highlight the experimental implications of this validation.

  6. [Vitrectomy in treatment of retinal detachment with proliferative vitreoretinopathy].

    PubMed

    Nawrocki, J; Dziegielewski, K; Pikulski, Z

    1993-01-01

    The authors presented their experiences concerning the treatment of 26 eyes (in 25 patients) with retinal detachment complicated by PVR in which pars plana vitrectomy and silicone oil tamponade were applied. The patients have been previously operated with traditional methods however without success. Positive results, it is retinal attachment completely or in the superior and central part of the fundus with residual detachment inferiorly were achieved in 19 eyes (73%). An useful visual acuity (> 1/50) was achieved in 12 eyes and in 7 (27%) it was better than 5/50. Our results confirmed that this method (pars plana vitrectomy with silicone oil tamponade) is a method of choice in complicated retinal detachment, in which traditional methods failed.

  7. Characterizing the Outer Divertor Leg Transition to Full Detachment

    NASA Astrophysics Data System (ADS)

    McLean, A. G.; Allen, S. L.; Fenstermacher, M. E.; Lasnier, C. J.; Meyer, W. H.; Porter, G. D.; Soukhanovskii, V. A.; Bray, B. D.; Carlstrom, T. N.; Leonard, A. W.; Liu, C.; Eldon, D.; Groth, M.; Stangeby, P. C.; Tsui, C. K.

    2013-10-01

    Experiments at DIII-D have explored the transition from an attached to fully detached divertor condition in L- and H-mode with an unprecedented level of detail. Improved divertor Thomson scattering capturing Te <= 1 eV, coupled with high resolution spectroscopic studies of molecular and neutral emissions, and Stark broadening of the deuterium Paschen series provide essential data for modeling the transition to detachment. 2D Te and ne profiles of the outer leg reveal movement of the ionization front away from the plate not replicated in modeling. Measured Paschen and molecular emissions suggest the onset of recombination occurs prior to, and to a greater extent than modeled. These data help guide and expose any missing physics in predictions for detached operation in future devices. This work supported in part by the US Department of Energy under DE-AC52-07NA27344 and DE-FC02-04ER54698.

  8. [Retinal pneumopexy in the treatment of rhegmatogenous retinal detachment].

    PubMed

    Levai, L; Gavriş, Monica; Gábor, Radó; Bagosi, P

    2014-01-01

    To evaluate the efficiency of retinal pneumopexy in patients with rhegmatogenous retinal detachment. This clinical prospective study unrolled between november 2010-june 2012 in the Ophthalmology Department of the Military Hospital in Cluj-Napoca and Satu Mare Emergency Hospital included 20 patients (20 eyes) with rhegmatogenous retinal detachment. Patients were treated with retinal pneumopexy followed by laser photocoagulation. Anatomical and functional results were evaluated 1, 3, 6, 12 and 19 months after treatment. In 17 eyes out of 20, we achieved retinal reattachment and visual recovery. Three cases yelded no success, these being further treated with posterior vitrectomy. Retinal pneumopexy is a minimally invasive treatment method of rhegmatogenous retinal detachment with very good results in well selected cases.

  9. Detached Solidification of Germanium-Silicon Crystals on the ISS

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.; Croell, A.

    2016-01-01

    A series of Ge(sub 1-x) Si(sub x) crystal growth experiments are planned to be conducted in the Low Gradient Furnace (LGF) onboard the International Space Station. The primary objective of the research is to determine the influence of containment on the processing-induced defects and impurity incorporation in germanium-silicon alloy crystals. A comparison will be made between crystals grown by the normal and "detached" Bridgman methods and the ground-based float zone technique. Crystals grown without being in contact with a container have superior quality to otherwise similar crystals grown in direct contact with a container, especially with respect to impurity incorporation, formation of dislocations, and residual stress in crystals. "Detached" or "dewetted" Bridgman growth is similar to regular Bridgman growth in that most of the melt is in contact with the crucible wall, but the crystal is separated from the wall by a small gap, typically of the order of 10-100 microns. Long duration reduced gravity is essential to test the proposed theory of detached growth. Detached growth requires the establishment of a meniscus between the crystal and the ampoule wall. The existence of this meniscus depends on the ratio of the strength of gravity to capillary forces. On Earth, this ratio is large and stable detached growth can only be obtained over limited conditions. Crystals grown detached on the ground exhibited superior structural quality as evidenced by measurements of etch pit density, synchrotron white beam X-ray topography and double axis X-ray diffraction.

  10. Numerical Optimization of the Thermal Field in Bridgman Detached Growth

    NASA Technical Reports Server (NTRS)

    Stelian, C.; Volz, M. P.; Derby, J. J.

    2009-01-01

    The global modeling of the thermal field in two vertical Bridgman-like crystal growth configurations, has been performed to get optimal thermal conditions for a successful detached growth of Ge and CdTe crystals. These computations are performed using the CrysMAS code and expand upon our previous analysis [1] that propose a new mechanism involving the thermal field and meniscus position to explain stable conditions for dewetted Bridgman growth. The analysis of the vertical Bridgman configuration with two heaters, used by Palosz et al. for the detached growth of Ge, shows, consistent with their results, that the large wetting angle of germanium on boron nitride surfaces was an important factor to promote a successful detached growth. Our computations predict that by initiating growth much higher into the hot zone of the furnace, the thermal conditions will be favorable for continued detachment even for systems that did not exhibit high contact angles. The computations performed for a vertical gradient freeze configuration with three heaters representative of that used for the detached growth of CdTe, show favorable thermal conditions for dewetting during the entirely growth run described. Improved thermal conditions are also predicted for coated silica crucibles when the solid-liquid interface advances higher into the hot zone during the solidification process. The second set of experiments on CdTe growth described elsewhere has shown the reattachment of the crystal to the crucible after few centimeters of dewetted growth. The thermal modeling of this configuration shows a second solidification front appearing at the top of the sample and approaching the middle line across the third heater. In these conditions, the crystal grows detached from the bottom, but will be attached to the crucible in the upper part because of the solidification without gap in this region. The solidification with two interfaces can be avoided when the top of the sample is positioned below

  11. Retinal Detachment Associated With Basketball-Related Eye Trauma.

    PubMed

    Lee, Tsung-Han; Chen, Yi-Hao; Kuo, Hsi-Kung; Chen, Yung-Jen; Chen, Chih-Hsin; Lee, Jong-Jer; Wu, Pei-Chang

    2017-08-01

    Basketball is a popular sport involving significant body contact, which may frequently result in ocular trauma. The aim of this study was to evaluate the characteristics and visual outcomes of retinal detachment associated with basketball-related injury. Retrospective, interventional case series. We reviewed the course of patients who sustained traumatic retinal detachment from basketball-related ocular trauma between 2003 and 2015. Thirteen patients were evaluated for basketball-related traumatic retinal detachment. Twelve (92%) were male and 1 (8%) female, with an average age of 18.2 years. The majority (9 of 13, 70%) of patients had moderate-to-high myopia, and none were using protective eyewear when they sustained the eye trauma. Rhegmatogenous retinal detachment was observed in all eyes. The preoperative mean visual acuity was 20/625 (range, hand motions to 20/20). Initial surgery using scleral buckling alone was performed in most (8 of 13, 62%) of the patients. Retinal reattachment was achieved in 10 (76%) eyes after the first operation and in 12 (92%) at the end of the intervention. The mean follow-up was 3.9 years (range, 4 months to 12 years). The visual acuity during last follow-up was 20/231 (range, light perception to 20/20). In the multivariable analysis, initial visual acuity was an independent factor affecting the final visual outcome (P = .006). Retinal detachment associated with basketball-related injury may cause severe visual loss. In the current study, all retinal detachments were of rhegmatogenous type and commonly occurred in young individuals with myopia. Initial visual acuity was associated with the prognosis. Risk awareness for early detection and intervention are important in these traumas. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Ultrasonic localization of choroidal detachment associated with flat anterior chamber.

    PubMed

    Portney, G L; Kohl, J W

    1975-01-01

    In postoperative patients with flat anterior chambers and small pupils or dense media, A-scan and B-scan ultrasonography can be useful tools in establishing the proper etiologic diagnosis. By searching for the presence of a choroidal detachment and determining its full location, complete drainage of the suprachoroidal fluid can be accomplished satisfactorily should this form of surgical intervention become necessary. If sufficient evidence of a choroidal detachment is not found, then therapy can be more assuredly directed at relief of pupillary block or reduction of excessive fistulization, other causes of a flat chamber.

  13. Pseudophakic flat anterior chamber following retinal detachment repair.

    PubMed

    Taylor, B C; Winslow, R L

    1981-09-01

    Flat anterior chambers were caused by varying mechanisms in 10 of 70 consecutive pseudophakic eyes operated on for retinal detachment. With iris or capsular implant fixation, three of 46 (7%) developed flat anterior chambers, and with anterior chamber lenses, the occurrence was seven of 24 (29%). Events initiating flat chambers included wound leak, pupillary block, and choroidal detachment. In eyes with flat anterior chambers, the retina could not be reattached in one case, extensive peripheral anterior synechia with persistent intraocular pressure elevation occurred in another case, and bullous keratopathy remained in two additional instances. Endothelial cell densities were obtained in eight eyes and were low on an age-related basis.

  14. [Recovery of rod and cone systems after retinal detachment surgery].

    PubMed

    Alexandridis, E

    1979-01-01

    The paper reports on the threshold values for light perception of circumscript retinal areas for different adaptation levels in patients successfully operated for retinal detachment. The examinations were carried out by means of the Tübingen projection perimeter, using the method of static perimetry in a meridian containing an approximately equal area of healthy and of formerly detached retina. The main aim of this examination was to establish whether both retinal photoreceptor systems recover within the same time after the operation. There is various evidence that the restitutions of the rod and cone systems do not occur at the same time.

  15. Cenozoic Evolution of the West Cycladic Detachment System

    NASA Astrophysics Data System (ADS)

    Iglseder, Christoph; Grasemann, Bernhard; Schneider, Dave A.; Senkowski, Carley A.; Stöckli, Dani

    2010-05-01

    Extension in the Aegean led to the formation of metamorphic core complexes and domes, with multistage extensional detachments cutting rocks of the Attic-Cycladic Crystalline at different structural and lithostratigraphic levels. Four kinematic provenances are here distinguished in the Cycladic extensional detachment system: (1) The North (Andros-Ikaria) and (2) Central (Naxos-Paros) Cycladic Detachment Systems, showing top N/NE sense of shear; (3) the South Cycladic Detachment System (Ios-Amorgos), part of the South Cycladic Shear Zone, with evidence for two opposite kinematic domains, an older top S/SE and a younger top N/NW sense of shear. In contrast, the newly documented (4) West Cycladic Detachment System (Sifnos-Lavrion) is dominated by a top SW/SSW sense of shear. Low-angled extensional detachments nucleated in the ductile regime and show progressive overprinting by ductile-brittle and then brittle deformation processes on Kea, Kythnos and Serifos. On Sifnos, an older top NE and brittle-ductile younger event, with top SW kinematics has been documented. In comparison, on the Greek mainland in Attica, top SW/SSW sense of shear allows the regional structure to be expanded. At both Lavrion in Attica and Serifos, the extensional detachments were intruded by syn-tectonic Late Miocene granodiorites. Cenozoic extension in the Western Cyclades is suggested to begin in the Eocene, with early S-type granite intrusion on Serifos at 43-37 Ma (U-Pb zircon). This is supported by Eocene/Early Oligocene Rb/Sr and Ar/Ar (cooling) ages of hanging-wall schists and marbles. Similar cooling ages, (post-) dating high-pressure/low-temperature metamorphism, have been described from Sifnos. During the Oligocene/Miocene, a decrease in greenschist-facies ages has been determined on the Serifos-Kythnos-Kea transect. Similar ages of greenschist-facies metamorphism have also been found on Sifnos. Initial stages of the Serifos granodiorite intrusion, coeval with initiation of the main

  16. Evaluation of bacterial detachment rates in porous media

    SciTech Connect

    Peyton, B.M.; Hooker, B.S.; Skeen, R.S.; Cunningham, A.B.; Lundman, R.W.

    1994-05-01

    The ability of published biomass detachment rate expressions to describe experimental data obtained from porous media reactors using Pseudomonas aeruginosa grown aerobically on glucose was evaluated. A first-order rate expression on attached biomass concentration best reflected effluent substrate concentration for combined data sets. Detachment rate coefficient k{sub d1} was dependent on initial substrate concentration. Simulation of porous media reactor experiments indicated that responses using higher influent substrate concentrations possessed greater sensitivity to variations in k{sub d1}. Simulations of field bioremediation systems suggest the use of accurate biofilm development kinetics is important in the prediction of well bore biofouling.

  17. Evaluation of bacterial detachment rates in porous media

    SciTech Connect

    Peyton, B.M.; Skeen, R.S.; Hooker, B.S.

    1995-12-31

    The ability of published biomass detachment rate expressions to describe experimental data obtained from porous media reactors using Pseudomonas Mesa grown aerobically on glucose was evaluated. A first-order rate expression on attached biomass concentration best reflected effluent substrate concentration for combined data sets. Detachment rate coefficient k{sub d1} was dependent on initial substrate concentration. Simulation of porous media reactor experiments indicated that responses using higher influent substrate concentrations possessed greater sensitivity to variations in k{sub d1}. Simulations of field bioremediation systems suggest the use of accurate biofilm development kinetics is important in the prediction of well bore biofouling.

  18. DUAL ORIGIN OF AEROSOLS IN TITAN'S DETACHED HAZE LAYER

    SciTech Connect

    Cours, T.; Burgalat, J.; Rannou, P.; Rodriguez, S.; Brahic, A.

    2011-11-10

    We have analyzed scattered light profiles from the Cassini Imaging Science Subsystem, taken at the limb and at several large phase angles. We also used results from an occultation observed by Ultraviolet Imaging Spectrograph in the ultraviolet. We found that particles responsible for the scattering in the detached haze have an effective radius around 0.15 {mu}m and the aerosol size distribution follows a power law (exponent about -4.5). We discuss these results along with microphysical constraints and thermal equilibrium of the detached haze, and we conclude that only a strong interaction with atmospheric dynamics can explain such a structure.

  19. Magnetic Detachment and Plume Control in Escaping Magnetized Plasma

    SciTech Connect

    P. F. Schmit and N. J. Fisch

    2008-11-05

    The model of two-fluid, axisymmetric, ambipolar magnetized plasma detachment from thruster guide fields is extended to include plasmas with non-zero injection angular velocity profiles. Certain plasma injection angular velocity profiles are shown to narrow the plasma plume, thereby increasing exhaust efficiency. As an example, we consider a magnetic guide field arising from a simple current ring and demonstrate plasma injection schemes that more than double the fraction of useful exhaust aperture area, more than halve the exhaust plume angle, and enhance magnetized plasma detachment.

  20. 2. Overview showing Medical Detachment Barracks on both Ramp No. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. Overview showing Medical Detachment Barracks on both Ramp No. 5 (left buildings) and Ramp No. 6 (right buildings). View is to west from roof of Corridor A. Note that a pedestrian sidewalk separates buildings instead of a street for automobiles. In left foreground is the north end of Building No. 9962-B; followed by the north B-sides of Buildings Nos. 9963, 9964, 9965, 9966, 9967 and 9968 on Ramp No. 5. Large white building in far distance is a barracks on the other side of Wilson Avenue. - Madigan Hospital, Medical Detachment Barracks, Bounded by Wilson & McKinley Avenues & Garfield & Lincoln Streets, Tacoma, Pierce County, WA

  1. Bridgman Growth of Detached GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Kaiser, N.; Cobb, S. D.; Vujisic, L.; Motakef, S.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The growth of detached crystals by the Bridgman technique, in which the growing crystal is not in contact with the crucible wall, has been observed both on earth and in microgravity conditions. Such detachment has particularly been in evidence in microgravity experiments, where the pressure head of the molten sample is absent. At present, the mechanisms contributing to the detachment are not completely understood and until recently detachment has not been reproducibly obtained. Key parameters which must be considered are the contact angle between the melt and the crucible and the growth angle. Another essential parameter is the pressure difference between the annular gap around the solid below the melt and the volume above the melt. Here we present results of the growth of Ge(0.98)Si(0.02) using adjustments in the applied temperature profile to control the pressure difference between the bottom and top of the melt. The technique is less susceptible to sample contamination than controlling the pressure by connecting the crucible to external gas sources. Using this technique, a pressure difference is created by decreasing the temperature in the volume above the melt while the sample is molten but prior to growth. A maximum pressure difference approximately equal to the pressure head of the molten sample can thus be obtained. Several GeSi crystals were grown in pyrolitic boron nitride crucibles. When a pressure difference was applied, samples were reproducibly grown mostly detached. For comparison, samples were also grown in a configuration in which gas could pass freely between the gap below the melt and the volume above the melt and no pressure difference could be established. These samples were initially attached. Existence of detachment was determined both by measuring the radius of the samples with a profilometer and by observations of the sample surfaces with optical and electron microscopy. The gap thickness between the crucible and detached crystal was on the

  2. Magnetic Detachment and Plume Control in Escaping Magnetized Plasma

    SciTech Connect

    P. F. Schmit and N. J. Fisch

    2008-11-05

    The model of two-fluid, axisymmetric, ambipolar magnetized plasma detachment from thruster guide fields is extended to include plasmas with non-zero injection angular velocity profiles. Certain plasma injection angular velocity profiles are shown to narrow the plasma plume, thereby increasing exhaust efficiency. As an example, we consider a magnetic guide field arising from a simple current ring and demonstrate plasma injection schemes that more than double the fraction of useful exhaust aperture area, more than halve the exhaust plume angle, and enhance magnetized plasma detachment.

  3. Bilateral serous retinal detachments associated with IgA nephropathy.

    PubMed

    Andión-Fernández, M; Dorado-Fernández, T; Juárez-Casado, M A; Santamarina-Pernas, R

    2015-11-01

    A 41-year-old woman with a bilateral loss of visual acuity and a history of IgA nephropathy. The ophthalmic examination revealed bilateral neurosensory detachments that resolved completely after four months of peritoneal dialysis. Bilateral serous retinal detachments are a rare manifestation of IgA nephropathy, in which the etiology is probably multifactorial and their resolution depends on the underlying disease. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  4. Retinal detachment caused by Arruga suture scleral intrusion. Treatment.

    PubMed

    Sánchez-Vicente, J L; Rueda-Rueda, T; González-García, M L; López-Herrero, F; Sánchez-Vicente, P; Castilla-Lázpita, A

    2015-10-01

    We present the case of an 81-year-old man with retinal detachment caused by intrusion of an Arruga suture. The encircling buckle was located in the sub-retinal space and caused retinal breaks with retinal detachment A pars plana vitrectomy was performed along with intraocular cutting of the Arruga suture with retinal re-attachment. Copyright © 2014 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

  5. Rotational auto-detachment of dipole-bound anions

    NASA Astrophysics Data System (ADS)

    Ard, S. G.; Compton, R. N.; Garrett, W. R.

    2016-04-01

    Rotational auto-detachment of acetonitrile, trimethyl-acetonitrile, acetone, and cyclobutanone dipole-bound anions was studied under varying conditions in a Rydberg electron transfer (RET) time-of-flight apparatus. Varying amounts of auto-detachment was observed for anions with similar electron affinity and dipole moment, but different moments of inertia. These results were found to be consistent with predictions based on the calculated rotational spectra for these anions, highlighting the importance of critical binding properties in understanding the stability and lifetime of dipole bound systems.

  6. Repeat Descemetopexy after Descemet's Membrane Detachment following Phacoemulsification.

    PubMed

    Datar, Sameer; Kelkar, Aditya; Jain, Ashish K; Kelkar, Jai; Kelkar, Shreekant; Gandhi, Poonam; Shah, Rachna; Kedia, Ruchika

    2014-05-01

    Descemet's membrane detachment (DMD) is an uncommon condition with a wide range of possible etiologies. Probably the commonest cause is a localized detachment occurring after cataract extraction surgery. Descemetopexy gives good anatomic attachment rates and visual outcomes and has become the standard treatment for DMD. However, in cases with failed initial descemetopexy, the next step in the management of such cases remains unclear. Before initiating a complex surgical procedure like keratoplasty, which requires good postoperative care and regular follow-ups, repeat descemetopexy with a long-term tamponade using 14% C3F8 gas for recurrent DMD is definitely a worthwhile attempt.

  7. Shock detachment process on cones in hypervelocity flows

    NASA Astrophysics Data System (ADS)

    Leyva, Ivett A.

    1999-11-01

    The shock detachment process on cones in hypervelocity flows is one of the most sensitive flows to relaxation effects. The critical angle for shock detachment under frozen conditions can be very different from the critical angle under chemical and thermal equilibrium. The rate of increase of the detachment distance with cone angle is also affected by the relaxation rate. The purpose of this study is to explain the effects of nonequilibrium on the shock detachment distance and its growth rate on cones in hypervelocity flows. The study consists of an experimental and a computational program. The experimental part has been carried out at Caltech's hypervelocity reflected shock tunnel (T5). Six different free-stream conditions have been chosen, four using N2 as the test gas and two using CO2. About 170 shots were performed on 24 cones. The cones range in diameter from 2 cm to 16 cm with half-angles varying from 55° to 75°. The experimental data obtained are holographic interferograms of every shot, and surface temperature and pressure measurements for the bigger cones. Extensive numerical simulations were made for the N2 flows and some were also made for the CO2 flows. The code employed is a Navier-Stokes solver that can account for thermal and chemical nonequilibrium in axisymmetric flows. The experimental and computational data obtained for the shock detachment distance confirms a previous theoretical model that predicts the detachment distance will grow more slowly for relaxing flows than for frozen or equilibrium flows. This difference is explained in terms of the behavior of the sonic line inside the shock layer. Different growth rates result when the detachment distance is controlled by the diameter of the cone (frozen and equilibrium cases) than when it is controlled by the extent of the relaxation zone inside the shock layer (nonequilibrium flows). The experimental data are also complemented with computational data to observe the behavior of the detachment

  8. The detached haze layer in Titan's mesosphere: The formation process

    NASA Astrophysics Data System (ADS)

    Lavvas, P.; Yelle, R. V.; Vuitton, V.

    2008-09-01

    Cassini observations made by the Imaging Science Subsystem (ISS) [1] and by the UltraViolet Imaging Spectrometer (UVIS) [2,3] have revealed the presence of a detached haze layer in Titan's mesosphere at an altitude of 520 km. Analysis of the observed optical properties presented in the accompanying talk [5], suggests that the average size of particles in the detached layer is of ~40 nm, with an imaginary index k < 0.3 at 187.5 nm and a number density of ˜30 particles cm-3, while calculations of the sedimentation velocity of the haze particles coupled with the derived number density imply a mass flux of 1.9-3.2 × 10-14 g cm-2 s-1. This is approximately equal to the mass flux required to explain the main haze layer and suggests that the main haze layer in Titan's stratosphere is formed primarily by sedimentation and coagulation of particles in the detached layer [5,6]. The HASI data clearly show that the haze is coincident with a temperature maximum. This rules out condensation as the source of the detached haze. We have also considered a more complicated scenario in which the detached layer is caused by an increase in the density of condensation nuclei near 520 km. This is motivated by the fact that silicate micrometeorites ablate near 500 km [7,8]. Recondensation of the refractory vapor creates `smoke' particles that could serve as condensation nuclei. Combination of Pioneer measurements along with theoretical estimations for the particles velocity distribution, suggest a mass flux of ~10-17 g cm-2 s-1 at Saturn's region [9], while measurements from the Cassini Dust Analyser (CDA) suggest a similar magnitude at Titan's location [10]. These fluxes are ~3 orders of magnitude smaller than the lower limit of the estimated mass flux out of the detached haze layer, so meteorite ablation can not be the direct cause of the aerosol layer. However, if the ablated meteoritic material reforms 1 nm particles, the implied number flux would be 2.4 × 103 particles cm-2 s-1

  9. Existence and Stability of Menisci in Detached Bridgman Growth

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2011-01-01

    Detached growth, also referred to as dewetted growth, is a Bridgman crystal growth process in which the melt is in contact with the crucible wall but the crystal is not. A meniscus bridges the gap between the top of the crystal and the crucible wall. The Young-Laplace capillary equation was used to calculate the crystal radii of detached states as a function of the pressure differential across the meniscus. The detached states depend on the contact angle of the melt with the crucible wall, the growth angle of the melt with respect to the solidifying crystal, and the Bond number. A static stability analysis was performed on the calculated detached states. The stability criterion was the sign of the second variation of the potential energy upon admissible meniscus shape perturbations. The conditions considered corresponded to the growth of Ge and InSb, in both terrestrial and microgravity conditions. Stability was found to depend significantly on whether the interior surface was considered to be microscopically rough or smooth, corresponding to pinned or unpinned states. It was also found that all meniscus shapes which are single-valued functions of the radius are statically stable in a microgravity environment.

  10. Turbulent Simulations of Divertor Detachment Based On BOUT + + Framework

    NASA Astrophysics Data System (ADS)

    Chen, Bin; Xu, Xueqiao; Xia, Tianyang; Ye, Minyou

    2015-11-01

    China Fusion Engineering Testing Reactor is under conceptual design, acting as a bridge between ITER and DEMO. The detached divertor operation offers great promise for a reduction of heat flux onto divertor target plates for acceptable erosion. Therefore, a density scan is performed via an increase of D2 gas puffing rates in the range of 0 . 0 ~ 5 . 0 ×1023s-1 by using the B2-Eirene/SOLPS 5.0 code package to study the heat flux control and impurity screening property. As the density increases, it shows a gradually change of the divertor operation status, from low-recycling regime to high-recycling regime and finally to detachment. Significant radiation loss inside the confined plasma in the divertor region during detachment leads to strong parallel density and temperature gradients. Based on the SOLPS simulations, BOUT + + simulations will be presented to investigate the stability and turbulent transport under divertor plasma detachment, particularly the strong parallel gradient driven instabilities and enhanced plasma turbulence to spread heat flux over larger surface areas. The correlation between outer mid-plane and divertor turbulence and the related transport will be analyzed. Prepared by LLNL under Contract DE-AC52-07NA27344. LLNL-ABS-675075.

  11. Cohesive detachment of an elastic pillar from a dissimilar substrate

    NASA Astrophysics Data System (ADS)

    Fleck, N. A.; Khaderi, S. N.; McMeeking, R. M.; Arzt, E.

    The adhesion of micron-scale surfaces due to intermolecular interactions is a subject of intense interest spanning electronics, biomechanics and the application of soft materials to engineering devices. The degree of adhesion is sensitive to the diameter of micro-pillars in addition to the degree of elastic mismatch between pillar and substrate. Adhesion-strength-controlled detachment of an elastic circular cylinder from a dissimilar substrate is predicted using a Dugdale-type of analysis, with a cohesive zone of uniform tensile strength emanating from the interface corner. Detachment initiates when the opening of the cohesive zone attains a critical value, giving way to crack formation. When the cohesive zone size at crack initiation is small compared to the pillar diameter, the initiation of detachment can be expressed in terms of a critical value Hc of the corner stress intensity. The estimated pull-off force is somewhat sensitive to the choice of stick/slip boundary condition used on the cohesive zone, especially when the substrate material is much stiffer than the pillar material. The analysis can be used to predict the sensitivity of detachment force to the size of pillar and to the degree of elastic mismatch between pillar and substrate.

  12. Spontaneous resolution of optic nerve coloboma-associated retinal detachment.

    PubMed

    Ying, Michelle S; Fuller, Jeff; Young, Joshua; Marcus, Dennis M

    2004-01-01

    We report a congenital neurosensory retinal detachment associated with an optic nerve coloboma with subsequent spontaneous reattachment. This represents the earliest reported case of such a clinical situation. An observation period is recommended for infants with this clinical course to allow for the opportunity of spontaneous reattachment.

  13. Macular holes associated with diabetic tractional retinal detachments.

    PubMed

    Mason, John O; Somaiya, Mamta D; White, Milton F; Vail, Rachel S

    2008-01-01

    Evaluation of surgical treatment of full-thickness macular holes secondary to diabetic tractional retinal detachments was conducted. A retrospective review of medical records, fluorescein angiograms, fundus photographs, optical coherence tomography images, and operative findings of six consecutive patients with full-thickness macular holes and diabetic tractional retinal detachments was completed. Each eye was treated with pars plana vitrectomy, tractional retinal detachment repair, membranectomy, indocyanine green-assisted internal limiting membrane peeling, and intraocular gas tamponade. Surgical intervention resulted in the closure of all full-thickness macular holes. Mean best-corrected visual acuity was 20/250 preoperatively and 20/100 postoperatively, with all patients having improvement after a mean follow-up of 10 months. Closure of tractional retinal detachments related to full-thickness macular holes can be achieved via pars plana vitrectomy, complete membranectomy, and intraocular gas. Vitrectomy with dissection of proliferative membranes helps to relieve the tractional forces responsible for full-thickness macular hole formation, enabling successful closure of the diabetic full-thickness macular holes and resulting in visual acuity improvement.

  14. Detachment faults:Evidence for a low-angle origin

    NASA Astrophysics Data System (ADS)

    Scott, Robert J.; Lister, Gordon S.

    1992-09-01

    The origin of low-angle normal faults or detachment faults mantling metamorphic core complexes in the southwestern United States remains controversial. If σ1 is vertical during extension, the formation of, or even slip along, such low-angle normal faults is mechanically implausible. No records exist of earthquakes on low-angle normal faults in areas currently undergoing continental extension, except from an area of actively forming core complexes in the Solomon Sea, Papua New Guinea. In light of such geophysical and mechanical arguments, W. R. Buck and B. Wernicke and G. J. Axen proposed models in which detachment faults originate as high-angle normal faults, but rotate to low angles and become inactive as extension proceeds. These models are inconsistent with critical field relations in several core complexes. The Rawhide fault, an areally extensive detachment fault in western Arizona, propagated at close to its present subhorizontal orientation late in the Tertiary extension of the region. Neither the Wernicke and Axen nor Buck models predict such behavior; in fact, both models preclude the operation of low-angle normal faults. We must seek alternative explanations or modify existing models to explain the evidence that detachment faults form and operate with gentle dips.

  15. Validation of patient symptom diary in acute posterior vitreous detachment

    PubMed Central

    Schweitzer, Kelly D.; Eneh, Amaka A.; Hurst, Jonathan; Bona, Mark D.; Rahim, Karim J.; Abouammoh, Marwan; Sharma, Sanjay

    2011-01-01

    Purpose The purpose of the study is to determine the validity of an original patient symptom diary in recording symptoms of posterior vitreous detachment (PVD). Methods In this prospective cohort study, all patients presenting to the Hotel Dieu hospital emergency eye clinic between September 2008 and July 2009 diagnosed with acute PVD were offered enrollment in the study. Patients were given the Queen’s University posterior vitreous detachment patient diary at the initial visit after detailed eye examination, assessment of risk factors for retinal tears and detachments and a thorough explanation of their presenting complaints to record their symptoms related to PVD. At a random point during their six-week follow up, the patients were verbally asked the same questions being recorded in the diary over the phone. At the six-week follow up visit, the diaries were collected and the verbal results were compared with the written results. Results There was substantial to near perfect agreement between the verbal questions and written answers. Cohen’s kappa scores for flash frequency, flash intensity, floater frequency, and floater type were 0.6229, 0.6389, 0.6495, and 0.8603, respectively. Conclusions The Queen’s University posterior vitreous detachment patient diary is a useful tool for investigating the quantity, quality and change in symptoms of patients presenting with PVD in the first 6 weeks of initial presentation. PMID:23960920

  16. Detachment faults: Evidence for a low-angle origin

    SciTech Connect

    Scott, R.J.; Lister, G.S. )

    1992-09-01

    The origin of low-angle normal faults or detachment faults mantling metamorphic core complexes in the southwestern United States remains controversial. If [sigma][sub 1] is vertical during extension, the formation of, or even slip along, such low-angle normal faults is mechanically implausible. No records exist of earthquakes on low-angle normal faults in areas currently undergoing continental extension, except from an area of actively forming core complexes in the Solomon Sea, Papua New Guinea. In light of such geophysical and mechanical arguments, W.R. Buck and B. Wernicke and G.J. Axen proposed models in which detachment faults originate as high-angle normal faults, but rotate to low angles and become inactive as extension proceeds. These models are inconsistent with critical field relations in several core complexes. The Rawhide fault, an areally extensive detachment fault in western Arizona, propagated at close to its present subhorizontal orientation late in the Tertiary extension of the region. Neither the Wernicke and Axen nor Buck models predict such behavior; in fact, both models preclude the operation of low-angle normal faults. The authors recommend that alternative explanations or modifications of existing models are needed to explain the evidence that detachment faults form and operate with gentle dips.

  17. Sampling device with a capped body and detachable handle

    DOEpatents

    Jezek, Gerd-Rainer

    2000-01-01

    The apparatus is a sampling device having a pad for sample collection, a body which supports the pad, a detachable handle connected to the body and a cap which encloses and retains the pad and body to protect the integrity of the sample.

  18. Engineering Design Guidance for Detached Breakwaters as Shoreline Stabilization Structure

    DTIC Science & Technology

    1993-12-01

    Lakeview Park shoreline. Combinations of wave height, period, direction, and still-water levels were studied to determine test conditions that produced a...77 Structural Design Objectives ........................... 77 Design Wave and Water Level Selection .................... 77...Chesapeake Bay at Bay Ridge, Maryland ................... 9 Figure 8. Aerial view of Lakeview Park , Lorain, Ohio ......... 13 Figure 9. Detached

  19. Characterizing the transition from high recycling to partial detachment

    NASA Astrophysics Data System (ADS)

    McLean, A. G.; Allen, S. L.; Fenstermacher, M.; Lasnier, C.; Meyer, W. H.; Porter, G.; Soukhanovskii, V.; Bray, B. D.; Carlstrom, T. N.; Leonard, A. W.; Liu, C.; Eldon, D.; Groth, M.; Stangeby, P. C.; Tsui, C.

    2014-10-01

    Experiments at DIII-D have explored the transition from the high recycling to the partially detached divertor condition in L- and H-mode with an unprecedented level of detail. Improved divertor and core Thomson scattering diagnostics were coupled with high resolution spectroscopic studies of molecular and neutral emissions. 2-D Te and ne profiles of the outer leg reveal the earliest indications of formation of the detachment front at the target plate, reducing local Te at the outer strike point from 8-10 eV to 2-3 eV with a marginal (< 10 %) increase in upstream. These data help guide and expose any missing physics in simulations of detachment onset using state-of-the-art boundary codes, and in predictions for operation with a partial detached divertor in future devices. This work supported in part by the US Department of Energy under DE-AC52-07NA27344 and DE-FC02-04ER54698.

  20. Commitment and Detachment in English and Bulgarian Academic Writing.

    ERIC Educational Resources Information Center

    Vassileva, Irena

    2001-01-01

    Examines similarities and differences in the degree of commitment and detachment in English, Bulgarian, and Bulgarian English research articles in linguistics. Analysis shows considerable difference in the overall distribution of hedges and boosters throughout the introductions, discussions, and conclusions of the articles, which may lead to…

  1. Rear Detachments: Capturing and Resourcing How the Army Fights

    DTIC Science & Technology

    2012-03-22

    operations/ plans officer), is the Rear Detachment Commander. Captain Basil H. Liddell-Hart was correct in noting that “even the bonds of patriotism...January, 2010; Kyle Moore and Erica Koelder, “Family Readiness in the ARFORGEN Cycle,” Engineer, May/August 2010. 8 Godwin, The Mission, Organization

  2. Liquid Droplet Detachment and Entrainment in Microscale Flows

    NASA Astrophysics Data System (ADS)

    Hidrovo, Carlos

    2005-11-01

    In this talk we will present a first order study of liquid water detachment and entrainment into air flows in hydrophobic microchannels. Silicon based microstructures consisting of 23 mm long U-shaped channels of different geometry were used for this purpose. The structures are treated with a Molecular Vapor Deposition (MVD) process that renders them hydrophobic. Liquid water is injected through a side slot located 2/3 of the way downstream from the air channel inlet. The water entering the air channel beads up into slugs or droplets that grow in size at this injection location until they fill and flood the channel or are carried away by the air flow. The slugs/droplets dimensions at detachment are correlated against superficial gas velocity and proper dimensionless parameters are postulated and examined to compare hydrodynamic forces against surface tension. It is found that slug/droplet detachment is dominated by two main forces: pressure gradient drag, arising from confinement of a viscous flow in the channel, and inertial drag, arising from the stagnation of the air due to obstruction by the slugs/droplets. A detachment regime map is postulated based on the relative importance of these forces under different flow conditions.

  3. [Surgical treatment of very advanced rhegmatogenous retinal detachment].

    PubMed

    Hejsek, L; Ernest, J; Němec, P; Rejmont, L; Manethová, K; Stepanov, A; Rozsíval, P

    2013-12-01

    Rhegmatogenous retinal detachment is a serious ocular pathology. Therapeutic options are surgical only. Surgery is in advanced stages technically and financially demanding. In this paper, we consider the results operated detachments, which were for their advancement, with respect to the technical possibilities of the present intraocular surgery, on the border of the surgical possibilities. The group consisted of 37 eyes of 37 patients who were followed prospectively and had in the affected eye very advanced (old) rhegmatogenous retinal detachment. As a method to confirtm any visual functions were used visual evoked potentials in flash monocular stimulation (F-VEP). All patients had a cerclage performed 12 mm from the limbus, 20G pars plana vitrectomy (PPV), in 2 was also performed cataract surgery (phacoemulsification with implantation of an artificial intraocular lens to the bag). Surgery was done in 23 of 37 patients (62 % of the whole group), with the remaining 14 eyes was not due to the severity of finding highly advanced retinal detachment. Attached retina at the end of the observation period had 14 eyes (61% of the patients, 38% of the whole group). In 5 eyes was due to local re-detachment in the periphery only stabilized finding (22% of operated eyes, 14% of all). The values ​​of visual acuity in the subgroup of operated eyes were statistically significantly increased after surgery (Wilcoxon p = 0.036). The values ​​of F-VEP were not statistically significantly different between operated and non-operated patients and was not found any statistically significant correlation between the vision (and even after surgery) and F-VEP in operated eyes. Anatomical success of surgical treatment of advanced retinal detachment is possible. But the correlation was not found in visual acuity and F-VEP or the severity of preoperative disturbed visual function, even in the improvement in the postoperative period. F-VEP is not a suitable marker for determining the

  4. Experimental Characterization of Plasma Detachment from Magnetic Nozzles

    NASA Astrophysics Data System (ADS)

    Olsen, Christopher Scott

    Magnetic nozzles, like Laval nozzles, are observed in several natural systems and have application in areas such as electric propulsion and plasma processing. Plasma flowing through these nozzles is inherently tied to the field lines and must separate for momentum redirection or particle transport to occur. Plasma detachment and associated mechanisms from a magnetic nozzle are investigated. Experimental results are presented from the plume of the VASIMRRTM VX-200 device flowing along an axisymmetric magnetic nozzle and operated at two ion energies to explore momentum dependent detachment. The argon plume expanded into a 150m3 vacuum chamber where the background pressure was low enough that charge-exchange mean-free-paths were longer than experiment scale lengths. This magnetic nozzle system is demonstrated to hydrodynamically scale up to astrophysical plasmas, particularly the solar chromosphere, implying general relevance to many systems. Plasma parameters were mapped over a large spatial range using measurements from multiple plasma diagnostics. The data show that the plume does not follow the magnetic field lines. A mapped integration of the ion flux shows the plume may be divided into three regions where 1) the plume briefly follows the magnetic flux, 2) diverges quadratically before 3) expanding with linear trajectories. Transitioning from region 1→2, the ion flux departs from the magnetic flux suggesting ion detachment. An instability forms in region 2 driving an oscillating electric field that causes ions to expand before enhancing electron cross-field transport through anomalous resistivity. Transitioning from region 2→3 the electric field dissipates, the trajectories linearize, and the plume effectively detaches. A delineation of sub-to-super Alfvenic flow aligns well with the inflection points of the linearization without a change in magnetic topology. The detachment process is best described as a two part process: First, ions detach by a breakdown of

  5. Seismic Slip on an Oblique Detachment Fault at Low Angles

    NASA Astrophysics Data System (ADS)

    Janecke, S. U.; Steely, A. N.; Evans, J. P.

    2008-12-01

    Pseudotachylytes are one of the few accepted indicators of seismic slip along ancient faults. Low-angle normal faults have produced few large earthquakes in historic times and low-angle normal faults (detachment faults) are typically severely misoriented relative to a vertical maximum compressive stress. As a result many geoscientists question whether low-angle normal faults produce earthquakes at low angles. Relationships in southern California show that a major low-angle normal-oblique fault slipped at low angles and produced large earthquakes. The exhumed Late Cenozoic West Salton detachment fault preserves spectacular fault- related pseudotachylytes along its fault plane and injected into its hanging wall and footwall. Composite pseudotachylyte zones are up to 1.25 m thick and persists over lateral distances of at least 10's of meters. Pseudotachylyte is common in most thin sections of damaged fault rocks with more than 20% (by volume) of cataclasite. We recognized the presence of original melt using numerous criteria: abundant spherulites in thin sections, injection structures at both the thin-section and outcrop scale, black aphanitic textures, quenched vein margins, variations in microcrystallite textures and/or size with respect to the vein margin, and glassy textures in hand sample. Multiple earthquakes are inferred to produce the layered "stratigraphy" in some exposures of pseudotachylytes. We infer that the West Salton detachment fault formed and slipped at low angles because it nearly perfectly reactivates a Cretaceous ductile thrust system at the half km scale and dips between 10 and 45 degrees. The about 30 degree NNE dip of the detachment fault on the north side of Yaqui Ridge is likely steeper than its dip during detachment slip because there is local steepening on the flanks of the Yaqui Ridge antiform in a contractional stepover of a crosscutting Quaternary San Felipe dextral fault zone. These relationships indicate a low dip on the detachment

  6. Bacterial detachment from salivary conditioning films by dentifrice supernates.

    PubMed

    van der Mei, Henny C; White, Donald J; Cox, Ed R; Geertsema-Doornbusch, Gesinda I; Busscher, Henk J

    2002-01-01

    This study compared the detachment by supernates of nine different dentifrices of four oral bacterial strains adhering to a salivary pellicle in a parallel plate flow chamber. Ultra-thin bovine enamel slabs were coated for 1.5 h with human whole saliva. Following buffer rinsing, a bacterial suspension of Streptococcus oralis, Streptococcus sanguis, Streptococcus mutans or Actinomyces naeslundii was perfused through the flow chamber at a shear rate of 30 s-1 for four hours, and the number of adhering bacteria n4h was enumerated by image analysis after buffer rinsing at the same shear rate. Then, a 25 wt%-dentifrice/water supernate was perfused through the flow chamber for four minutes, followed by eight minutes of buffer rinsing and another enumeration of the number of bacteria that had remained adhering nad. Finally, an air-bubble was passed through the flow chamber to mimic the occasionally high detachment forces occurring in the oral cavity, and the adhering bacteria nab were counted again. On average, S. sanguis was the easiest to detach (73% averaged over all dentifrice supernates), while A. naeslundii was the most difficult (22% on average). The combined detachment of bacteria by dentifrice supernates and air-bubble ranged from a low of 16% to a high of 80%. Dentifrices containing pyrophosphate and polymeric polyphosphate (hexametaphosphate) surface active ingredients appeared to produce the most consistent and strongest desorption effects on plaque bacteria. Factors apparently important to bacterial detachment from pellicle-covered tooth surfaces by dentifrice formulations include the nature of adhesion of bacterial strains and chemical composition of the dentifrice formulations, including pH, surfactant system and the effect of added ingredients (dispersants, metal ions, peroxides, baking soda).

  7. Critical taper analysis reveals lithological control of variations in detachment strength: An analysis of the Alpine basal detachment (Swiss Alps)

    NASA Astrophysics Data System (ADS)

    von Hagke, C.; Oncken, O.; Evseev, S.

    2014-01-01

    Although evidence for weak detachments underlying foreland thrust belts exists, very little is known about the lateral variations in effective strength, as well as the geological nature of such variations. Using critical taper analysis, we show that a detailed and systematic measurement of surface slope of the Central European Alps reveals variations in strength parameter F along the detachment, based on the argument that the Alps are close to the critical state. We show that the basal detachment is very weak near the deformation front but strengthens toward the hinterland. Very low F (effective coefficient of friction plus normalized cohesion) values of <0.1 and even 0.05 occur within evaporites and within shales in Triassic (west) or Upper Cretaceous/Lower Tertiary sequences (east) used by the Alpine sole detachment. These very low values in shales--comparably low values are reported from other orogens--are caused partly by slightly elevated pore pressures (λ > 0.54) but may also require additional mechanisms of dynamic weakening.

  8. Syphilis presenting as retinal detachment and orchitis in a young man with HIV.

    PubMed

    Yogo, Norihiro; Nichol, Aran Cunningham; Campbell, Thomas B; Erlandson, Kristine M

    2014-02-01

    Retinal detachment and testicular lesions are 2 rare presentations of syphilis. We describe a man with bilateral retinal detachment from ocular syphilis and syphilitic orchitis as a manifestation of syphilis and HIV coinfection.

  9. Detachment of solids and nitrifiers in integrated, fixed-film activated sludge systems.

    PubMed

    Maas, Carol L A; Parker, Wayne J; Legge, Raymond L

    2008-12-01

    Despite the importance of detachment to biofilm processes, detachment phenomena are not well understood. In this study, researchers investigated biofilm detachment from free-floating biofilm carriers that were established in an integrated, fixed-film activated sludge (IFAS) installation in Mississauga, Ontario. A method for assessing detachment from biofilm carrier systems was devised, evaluated, and refined during this study. In the absence of substrate, superficial air velocity significantly affected the 24-hour detachment rates of total suspended solids from the carriers. Short-term growth conditions did not appear to significantly affect the rate of detachment of solids and nitrifiers. The measured solids-detachment rates were found to be described by a second order function of biofilm attached growth total solids with a detachment coefficient of 0.006 +/- 0.0008 (g/m x d)(-1).

  10. Screening for anthracnose disease resistance in strawberry using a detached leaf assay

    USDA-ARS?s Scientific Manuscript database

    Inoculation of detached strawberry leaves with Colletotrichum species may provide a rapid, non-destructive method of identifying anthracnose resistant germplasm. The reliability and validity of assessing disease severity is critical to disease management decisions. We inoculated detached strawberr...

  11. Detection and quantification of microtubule detachment from centrosomes and spindle poles.

    PubMed

    Ganguly, Anutosh; Yang, Hailing; Cabral, Fernando

    2013-01-01

    Microtubule detachment from microtubule organizing centers is an important cellular process required for normal cell proliferation. When cells enter mitosis, microtubule turnover increases along with a concurrent increase in microtubule detachment. MCAK, a kinesin-related protein whose abundance is highest during the early stages of mitosis, has been shown to regulate microtubule detachment. Abnormal increases or decreases in the frequency of detachment interfere with spindle function and inhibit cell division. It has been shown that drugs able to promote microtubule assembly (e.g., paclitaxel, epothilones) prevent cell division by suppressing microtubule detachment from centrosomes. Conversely, cytotoxic concentrations of microtubule destabilizing drugs (e.g., vinblastine, nocodazole), tubulin mutations that cause paclitaxel resistance, and specific β-tubulin isotypes increase the frequency of microtubule detachment. In this chapter, we describe a method to calculate the frequency of microtubule detachment by transfecting cells with EGFP-MAP4 and directly observing detachment by live cell imaging.

  12. Mechanism of Inhibition of PP2A Activity and Abnormal Hyperphosphorylation of Tau by I2PP2A/SET

    PubMed Central

    Arnaud, Lisette; Chen, She; Liu, Fei; Li, Bin; Khatoon, Sabiha; Grundke-Iqbal, Inge; Iqbal, Khalid

    2011-01-01

    Protein phosphatase-2A (PP2A) activity, which is compromised in Alzheimer disease brain, is regulated by two endogenous inhibitors, one of them being I2PP2A, a 277 amino acid long protein also known as SET. Here we report that both the amino terminal fragment (I2NTF; aa 1–175) and the carboxy terminal fragment (I2CTF; aa 176–277) of I2PP2A inhibit PP2A by binding to its catalytic subunit PP2Ac and cause hyperphosphorylation of tau. The C-terminal acidic region in I2CTF and Val 92 in I2NTF are essential for their association with PP2Ac and inhibition of the phosphatase activity. PMID:21806989

  13. Downregulation of striatin leads to hyperphosphorylation of MAP2, induces depolymerization of microtubules and inhibits proliferation of HEK293T cells.

    PubMed

    Kaźmierczak-Barańska, Julia; Pęczek, Łukasz; Przygodzka, Patrycja; Cieślak, Marcin J

    2015-01-16

    Microtubules are tubular polymers of α/β-tubulin that are involved in the maintenance of cell shape, motility, and intracellular transport and in the segregation of chromosomes during cell division. Microtubules are dynamic structures, and their assembly is regulated by phosphoproteins called microtubule-associated proteins (MAPs). We propose that striatin, a protein belonging to the striatin family of proteins, is involved in regulation of microtubules. In HEK293T cells, striatin colocalizes with microtubules and stably associates with PP2Ac. Inhibition of striatin expression results in hyperphosphorylation of MAP2 and destabilizes microtubules. Striatin-induced destabilization of microtubules inhibited the proliferation of HEK293T cells and caused the accumulation of cells in the G0/G1 phase of the cell cycle. These results suggest that the PP2A/striatin complex modulates microtubule dynamics by regulating MAP2 phosphorylation.

  14. Induction of intracellular tau aggregation is promoted by α-synuclein seeds and provides novel insights into the hyperphosphorylation of tau.

    PubMed

    Waxman, Elisa A; Giasson, Benoit I

    2011-05-25

    Intracytoplasmic proteinaceous inclusions, primarily composed of tau or α-synuclein (α-syn), are predominant pathological features of Alzheimer's disease (AD) and Parkinson's disease (PD), respectively. However, the coexistence of these pathological aggregates is identified in many neurodegenerative disorders, including spectrum disorders of AD and PD. Whereas α-syn can spontaneously polymerize into amyloidogenic fibrils, in vitro, tau polymerization requires an inducing agent. The current study presents a human-derived cellular model, in which recombinant, preformed α-syn fibrils cross-seed intracellular tau to promote the formation of neurofibrillary tangle-like aggregates. These aggregates were hyperphosphorylated, Triton insoluble, and thioflavin-S positive, either comingling with endogenously expressed α-syn aggregates or induced by only exogenously applied recombinant α-syn fibrils. Furthermore, filamentous, amyloidogenic tau took over the cellular soma, displacing the nucleus and isolating or displacing organelles, likely preventing cellular function. Although a significant proportion of wild-type tau formed these cellular inclusions, the P301L mutation in tau increased aggregation propensity resulting from α-syn seeds to over 50% of total tau protein. The role of phosphorylation on the development of these tau aggregates was investigated by coexpressing glycogen synthase kinase 3 β or microtubule-associated protein/microtubule affinity-regulating kinase 2. Expression of either kinase inhibited the formation of α-syn-induced tau aggregates. Analyses of phosphorylation sites suggest that multiple complex factors may be associated with this effect and that Triton-soluble versus Triton-insoluble tau may be independently targeted by kinases. The current work not only provides an exceptional cellular model of tau pathology, but also examines α-syn-induced tau inclusion formation and provides novel insights into hyperphosphorylation observed in disease.

  15. Induction of intracellular tau aggregation is promoted by α-synuclein seeds, and provides novel insights into the hyperphosphorylation of tau

    PubMed Central

    Waxman, Elisa A.; Giasson, Benoit I.

    2011-01-01

    Intracytoplasmic proteinaceous inclusions, primarily composed of tau or α-synuclein (α-syn), are predominant pathological features of Alzheimer’s disease (AD) and Parkinson’s disease (PD), respectively. However, the co-existence of these pathological aggregates is identified in many neurodegenerative disorders, including spectrum disorders of AD and PD. While α-syn can spontaneously polymerize into amyloidogenic fibrils, in vitro, tau polymerization requires an inducing agent. The current study presents a human-derived cellular model, in which recombinant, pre-formed α-syn fibrils cross-seed intracellular tau to promote the formation of neurofibrillary tangle-like aggregates. These aggregates were hyperphosphorylated, Triton-insoluble, and thioflavin S-positive, either co-mingling with endogenously expressed α-syn aggregates, or induced by only exogenously applied recombinant α-syn fibrils. Further, filamentous, amyloidogenic tau took over the cellular soma, displacing the nucleus and isolating or displacing organelles, likely preventing cellular function. While a significant proportion of wild-type tau formed these cellular inclusions, the P301L mutation in tau increased aggregation propensity resulting from α-syn seeds to over 50% of total tau protein. The role of phosphorylation on the development of these tau aggregates was investigated by co-expressing glycogen synthase kinase 3 beta or MAP/microtubule affinity-regulating kinase 2. Expression of either kinase inhibited the formation of α-syn-induced tau aggregates. Analyses of phosphorylation sites suggest that multiple complex factors may be associated with this effect, and that Triton-soluble versus Triton-insoluble tau may be independently targeted by kinases. The current work not only provides an exceptional cellular model of tau pathology, but also examines α-syn-induced tau inclusion formation and provides novel insights into hyperphosphorylation observed in disease. PMID:21613474

  16. FLZ Alleviates the Memory Deficits in Transgenic Mouse Model of Alzheimer’s Disease via Decreasing Beta-Amyloid Production and Tau Hyperphosphorylation

    PubMed Central

    Wang, Tao; Kong, Xiang-Chen; Tai, Wen-Jiao; Sun, Hua; Zhang, Dan

    2013-01-01

    Alzheimer’s disease (AD) is the most common cause of dementia worldwide and mainly characterized by the aggregated β-amyloid (Aβ) and hyperphosphorylated tau. FLZ is a novel synthetic derivative of natural squamosamide and has been proved to improve memory deficits in dementia animal models. In this study, we aimed to investigate the mechanisms of FLZ’s neuroprotective effect in APP/PS1 double transgenic mice and SH-SY5Y (APPwt/swe) cells. The results showed that treatment with FLZ significantly improved the memory deficits of APP/PS1 transgenic mice and decreased apoptosis of SH-SY5Y (APPwt/swe) cells. FLZ markedly attenuated Aβ accumulation and tau phosphorylation both in vivo and in vitro. Mechanistic study showed that FLZ interfered APP processing, i.e., FLZ decreased β-amyloid precursor protein (APP) phosphorylation, APP-carboxy-terminal fragment (APP-CTF) production and β-amyloid precursor protein cleaving enzyme 1 (BACE1) expression. These results indicated that FLZ reduced Aβ production through inhibiting amyloidogenic pathway. The mechanistic study about FLZ’s inhibitory effect on tau phosphorylation revealed t the involvement of Akt/glycogen synthase kinase 3β (GSK3β) pathway. FLZ treatment increased Akt activity and inhibited GSK3β activity both in vivo and in vitro. The inhibitory effect of FLZ on GSK3β activity and tau phosphorylation was suppressed by inhibiting Akt activity, indicating that Akt/GSK3β pathway might be the possible mechanism involved in the inhibitory effect of FLZ on tau hyperphosphorylation. These results suggested FLZ might be a potential anti-AD drug as it not only reduced Aβ production via inhibition amyloidogenic APP processing pathway, but also attenuated tau hyperphosphoylation mediated by Akt/GSK3β. PMID:24223757

  17. Neuroinflammation, hyperphosphorylated tau, diffuse amyloid plaques, and down-regulation of the cellular prion protein in air pollution exposed children and young adults.

    PubMed

    Calderón-Garcidueñas, Lilian; Kavanaugh, Michael; Block, Michelle; D'Angiulli, Amedeo; Delgado-Chávez, Ricardo; Torres-Jardón, Ricardo; González-Maciel, Angelica; Reynoso-Robles, Rafael; Osnaya, Norma; Villarreal-Calderon, Rodolfo; Guo, Ruixin; Hua, Zhaowei; Zhu, Hongtu; Perry, George; Diaz, Philippe

    2012-01-01

    Air pollution exposures have been linked to neuroinflammation and neuropathology. Autopsy samples of the frontal cortex from control (n = 8) and pollution-exposed (n = 35) children and young adults were analyzed by RT-PCR (n = 43) and microarray analysis (n = 12) for gene expression changes in oxidative stress, DNA damage signaling, NFκB signaling, inflammation, and neurodegeneration pathways. The effect of apolipoprotein E (APOE) genotype on the presence of protein aggregates associated with Alzheimer's disease (AD) pathology was also explored. Exposed urbanites displayed differential (>2-fold) regulation of 134 genes. Forty percent exhibited tau hyperphosphorylation with pre-tangle material and 51% had amyloid-β (Aβ) diffuse plaques compared with 0% in controls. APOE4 carriers had greater hyperphosphorylated tau and diffuse Aβ plaques versus E3 carriers (Q = 7.82, p = 0.005). Upregulated gene network clusters included IL1, NFκB, TNF, IFN, and TLRs. A 15-fold frontal down-regulation of the prion-related protein (PrP(C)) was seen in highly exposed subjects. The down-regulation of the PrP(C) is critical given its important roles for neuroprotection, neurodegeneration, and mood disorder states. Elevation of indices of neuroinflammation and oxidative stress, down-regulation of the PrP(C) and AD-associated pathology are present in young megacity residents. The inducible regulation of gene expression suggests they are evolving different mechanisms in an attempt to cope with the constant state of inflammation and oxidative stress related to their environmental exposures. Together, these data support a role for air pollution in CNS damage and its impact upon the developing brain and the potential etiology of AD and mood disorders.

  18. Arctigenin Attenuates Learning and Memory Deficits through PI3k/Akt/GSK-3β Pathway Reducing Tau Hyperphosphorylation in Aβ-Induced AD Mice.

    PubMed

    Qi, Yue; Dou, De-Qiang; Jiang, Hong; Zhang, Bing-Bing; Qin, Wen-Yan; Kang, Kai; Zhang, Na; Jia, Dong

    2017-01-01

    Arctigenin is a phenylpropanoid dibenzylbutyrolactone lignan compound possessing antitumor, anti-inflammatory, anti-influenza, antioxidant, antibacterial, and hypoglycaemic activities. Our previous study demonstrated that arctigenin exerts neuroprotective effects both in vitro and in vivo in a Parkinson's disease model. However, the exact mechanism through which arctigenin improves amyloid beta-induced memory impairment by inhibiting the production of the hyperphosphorylated tau protein is unknown. Amyloid β1-42 was slowly administered via the intracerebroventricular route in a volume of 3 µL (≈ 410 pmmol/mouse) to mice. The mice were administered arctigenin (10, 40, or 150 mg/kg) or vehicle starting from the second day after amyloid β1-42 injection to the end of the experiment. Behavioural tests were performed from days 9 to 15. On day 16 after the intracerebroventricular administration of amyloid β1-42, the mice were sacrificed for biochemical analysis. Arctigenin (10-150 mg/kg) significantly attenuated the impairment of spontaneous alternation behaviours in the Y-maze task, decreased the escape latency in the Morris water maze test, and increased the swimming times and swimming distances to the platform located in the probe test. Arctigenin attenuated the level of phosphorylated tau at the Thr-181, Thr-231, and Ser-404 sites in the hippocampus, and increased the phosphorylation levels of phosphatidylinositol-3-kinase, threonine/serine protein kinase B, and glycogen synthase kinase-3β. Arctigenin effectively provides protection against learning and memory deficits and in inhibits hyperphosphorylated tau protein expression in the hippocampus. The possible mechanism may occur via the phosphatidylinositol-3-kinase/protein kinase B-dependent glycogen synthase kinase-3β signalling pathway.

  19. Detached macroalgae: Its importance to inshore sandy beach fauna

    NASA Astrophysics Data System (ADS)

    Orr, Kyla K.; Wilding, Thomas A.; Horstmeyer, Lena; Weigl, Simon; Heymans, Johanna J.

    2014-10-01

    Kelp forests shed a large proportion of their biomass through storm-mediated defoliation, senescence of kelp blades, and constant erosion of particulate organic matter from the kelp fronds. Much of this detached macroalgae drifts in the water column and is deposited on intertidal zones of beaches. Detached macroalgae may provide inshore sandy beach fauna with refuge and food subsidies in an exposed and bare environment, with limited in situ primary production. We evaluated the relationship between detached macroalgae and the density of inshore fauna, where 'inshore' was the body of water extending from low water seawards for approximately 50 m. Inshore fauna were sampled using a push-net (1 mm mesh) on 11 beaches, and using a beam-trawl (4 mm mesh) on a subset of 8 beaches. On each beach, the density of detached macroalgae in the water column was quantified, together with a suite of physico-chemical beach characteristics. Push-net samples principally comprised omnivorous and detritivorous crustaceans such as gammarid amphipods, mysids and valviferan isopods, which have limited swimming abilities and reside inshore year-round. Beam-trawl fauna were mainly carnivorous decapods and fish, which undergo seasonal inshore-offshore migrations to utilize sandy beaches as nursery habitats. Linear models predicted increases of 11% (95% CI: 3.5-19%) and 2.4% (95% CI: 0.7-4.2%) in the density of push-net and beam-trawl fauna, respectively, with a 1 ℓ.100 m-3 increase in detached macroalgae. This suggests that detached macroalgae is more important in the provision of food and shelter to small, weak-swimming detritivores/omnivores than to larger and more mobile predators. The densities of large predators were mostly explained by physical beach characteristics, which overshadowed the role of macroalgae. Maximum abundances of decapods and fish were found on wide, flat beaches with low wave heights. Large accumulations of macroalgae may inhibit the foraging efficiencies of

  20. Clinical features and surgical management of retinal detachment secondary to round retinal holes.

    PubMed

    Ung, T; Comer, M B; Ang, A J S; Sheard, R; Lee, C; Poulson, A V; Newman, D K; Scott, J D; Richards, A J; Snead, M P

    2005-06-01

    The majority of rhegmatogenous retinal detachments result from pathological posterior vitreous detachment (PVD) and secondary horseshoe or giant retinal tears. Retinal detachment without PVD is usually associated with either retinal dialysis or round retinal holes. This study characterises the features, surgical outcome, and incidence of bilateral involvement of detachment associated with round retinal holes. In all, 110 retinal detachments from 96 consecutive patients with retinal detachment secondary to round retinal holes were studied. Analysis of patient age, sex, refraction, preoperative visual acuity, presented symptoms, position and extent of detachment, number and distribution of holes present, posterior hyaloid membrane status, surgical management, outcome of surgery, and postoperative visual acuity were studied. The mean age for patients was 34 years with a marked female preponderance (64%) and myopia (83%). The posterior hyaloid membrane remained attached in 95 eyes (86%). In all, 45% patients had bilateral pathology, of which 33% had 'mirror image' distribution. Detachments were predominantly shallow (93%) and slow in progression (17%). A total of 100 detachments were repaired with cryotherapy and scleral buckling, eight with cryotherapy alone, and one with laser retinopexy. In all, 99% detachments were successfully reattached with a single procedure. The mean follow-up period was 2 years. There were no instances of redetachment. Round hole detachments are slowly evolving detachments with attached vitreous gel in young, predominantly female myopes. Examination of the fellow eye should be mandatory as there is a high incidence of bilateral pathology. Scleral buckling procedures remained highly effective in this selected group of patients.

  1. Inhibition of Cyclin-Dependent Kinase 5 but Not of Glycogen Synthase Kinase 3-β Prevents Neurite Retraction and Tau Hyperphosphorylation Caused by Secretable Products of Human T-Cell Leukemia Virus Type I-Infected Lymphocytes

    PubMed Central

    Maldonado, Horacio; Ramírez, Eugenio; Utreras, Elias; Pando, María E.; Kettlun, Ana M.; Chiong, Mario; Kulkarni, Ashok B.; Collados, Lucía; Puente, Javier; Cartier, Luis; Valenzuela, María A.

    2012-01-01

    Human T-cell leukemia virus type I (HTLV-I)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a neurodegenerative disease characterized by selective loss of axons and myelin in the corticospinal tracts. This central axonopathy may originate from the impairment of anterograde axoplasmic transport. Previous work showed tau hyperphosphorylation at T181 in cerebrospinal fluid of HAM/TSP patients. Similar hyperphosphorylation occurs in SH-SY5Y cells incubated with supernatant from MT-2 cells (HTLV-I-infected lymphocytes secreting viral proteins, including Tax) that produce neurite shortening. Tau phosphorylation at T181 is attributable to glycogen synthase kinase 3-β (GSK3-β) and cyclin-dependent kinase 5 (CDK5) activation. Here we investigate whether neurite retraction in the SH-SY5Y model associates with concurrent changes in other tau hyperphosphorylable residues. Threonine 181 turned out to be the only tau hyperphosphorylated residue. We also evaluate the role of GSK3-β and CDK5 in this process by using specific kinase inhibitors (LiCl, TDZD-8, and roscovitine). Changes in both GSK3-β active and inactive forms were followed by measuring the regulatory phosphorylable sites (S9 and Y216, inactivating and activating phosphorylation, respectively) together with changes in β-catenin protein levels. Our results showed that LiCl and TDZD-8 were unable to prevent MT-2 supernatant-mediated neurite retraction and also that neither Y216 nor S9 phosphorylations were changed in GSK3-β. Thus, GSK3-β seems not to play a role in T181 hyperphosphorylation. On the other hand, the CDK5 involvement in tau phosphorylation was confirmed by both the increase in its enzymatic activity and the absence of MT-2 neurite retraction in the presence of roscovitine or CDK5 siRNA transfection. PMID:21671254

  2. Detached solidification of InSb on earth

    NASA Astrophysics Data System (ADS)

    Wang, Jianbin; Regel, Liya L.; Wilcox, William R.

    2004-01-01

    Detached solidification of lightly gallium-doped indium antimonide was achieved in the laboratory only when the ampoule was coated with hexagonal boron nitride and when the material appeared to be oxide-free. A furnace was constructed with the temperature increasing with height in order to minimize bouyancy-driven convection, so as to maximize transport of segregated dissolved gases into the gap between the growing solid and the ampoule wall. There appeared to be no difference in results with freezing rates of 5 and 10 mm/h. Best results were obtained when the ampoule was backfilled with 20 kPa of Ar-10% H 2 prior to sealing. The detached portions were depressed by several μm from adjacent attached regions, were dull, and sometimes had microfacets and steps.

  3. Detached Solidification of InSb on Earth

    NASA Technical Reports Server (NTRS)

    Wang, Jianbin; Regel, Liya L.; Wilcox, William R.

    2003-01-01

    Detached solidification of lightly gallium-doped indium antimonide was achieved in the laboratory only when the ampoule was coated with hexagonal boron nitride and when the material appeared to be oxide-free. A furnace was constructed with the temperature increasing with height in order to minimize bouyancy-driven convection, so as to maximize transport of segregated dissolved gases into the gap between the growing solid and the ampoule wall. There appeared to be no difference in results with freezing rates of 5 mmh and 10 mm/h. Best results were obtained when the ampoule was backfilled with 20 kPa of Ar-10%H2 prior to sealing. The detached portions were depressed by several pm from adjacent attached regions, were rough, and sometimes had microfacets and steps.

  4. Peripapillary haemorrhagic retinal pigment epithelium detachment following radial optic neurotomy.

    PubMed

    Maia, Mauricio; Farah, Michel E; Aggio, Fabio B; Rodrigues, Eduardo B; de Souza, Eduardo C; Magalhães, Octaviano

    2007-01-01

    Central retinal vein occlusion is a common vascular cause of blidness. In this paper, we first report focal haemorrhagic pigment epithelium detachment and chorioretinal anastomosis in the peripapillary area as an intraoperative complication of radial optic neurotomy (RON). A 65-year-old white man presented with ischaemic central vein occlusion OS. He underwent vitrectomy with RON, panretinal photocoagulation and intravitreal injection of triamcinolone acetonide. A circumscribed subretinal haemorrhage was noted intraoperatively at the nasal site of the RON. The haemorrhage size decreased at the seventh postoperative day when an optical coherence tomography scan disclosed a haemorrhagic pigment epithelium detachment. Fluorescein angiography and fundus photograph revealed a chorioretinal anastomosis formation nasal to the optic nerve confirmed by indocyanine green angiography. Best-correlated visual acuity improved from hand movements to 6/18 at the fourth week and it was stable until last examination. This case illustrates the role of chorioretinal anastomosis formation in the vision improvement following RON.

  5. Aerosols particles properties in Titan's Detached Haze Layer

    NASA Astrophysics Data System (ADS)

    Seignovert, Benoît; Rannou, Pascal; Lavvas, Panayotis; Cours, Thibaud; West, Robert A.

    2016-06-01

    Titan's Detached Haze Layer (DHL) first observed in 1983 by Rages and Pollack during the Voyager 2 [1] is a consistent spherical haze feature surrounding Titan's upper atmosphere and detached from the main haze. Since 2005, the Imaging Science Subsystem (ISS) instrument on board the Cassini mission performs a continu- ous survey of the Titan's atmosphere and confirmed its persistence at 500 km up to the equinox (2009) before its drop and disappearance in 2012 [2]. Previous analyses showed, that this layer corresponds to the transition area between small spherical aerosols and large fractal aggregates and play a key role in the aerosols formation in Titan's atmosphere [3-5]. In this study we perform UV photometric analyses on ISS observations taken from 2005 to 2007 based on radiative transfer inversion to retrieve aerosols particles properties in the DHL (bulk and monomer size, fractal dimension and local density).

  6. The Role of Pericyte Detachment in Vascular Rarefaction

    PubMed Central

    Schrimpf, Claudia; Teebken, Omke E.; Wilhelmi, Mathias; Duffield, Jeremy S.

    2015-01-01

    Background Pericytes surround endothelial cells at the perivascular interface. Signaling between endothelial cells and pericytes is crucial for capillary homeostasis, as pericytes stabilize vessels and regulate many microvascular functions. Recently it has been shown that pericytes are able to detach from the vascular wall and contribute to fibrosis by becoming scar-forming myofibroblasts in many organs including the kidney. At the same time, the loss of pericytes within the perivascular compartment results in vulnerable capillaries which are prone to instability, pathological angiogenesis, and, ultimately, rarefaction. Aims This review will give an overview of pericyte-endothelial cell interactions, summarize the signaling pathways that have been identified to be involved in pericyte detachment from the vascular wall, and present pathological endothelial responses in the context of disease of the kidney. PMID:25195856

  7. Acute lymphoblastic leukemia presenting with bilateral serous macular detachment.

    PubMed

    Vieira, Luisa; Silva, Nuno Aguiar; Medeiros, Marco Dutra; Flores, Rita; Maduro, Vitor

    2015-01-01

    Acute lymphoblastic leukemia is a malignant hematopoietic neoplasia, which is rare in adults. Although ocular fundus alterations may be commonly observed in the course of the disease, such alterations are rarely the presenting signs of the disease. Here we describe the case of a patient with painless and progressive loss of visual acuity (right eye, 2/10; left eye, 3/10) developing over two weeks, accompanied by fever and cervical lymphadenopathy. Fundus examination showed bilateral macular serous detachment, which was confirmed by optical coherence tomography. Fluorescein angiography revealed hyperfluorescent pinpoints in the posterior poles. The limits of the macular detachment were revealed in the late phase of the angiogram. The results of blood count analysis triggered a thorough, systematic patient examination. The diagnosis of acute lymphoblastic leukemia B (CD10+) was established, and intensive systemic chemotherapy was immediately initiated. One year after the diagnosis, the patient remains in complete remission without any ophthalmologic alterations.

  8. Shape Evolution of Detached Bridgman Crystals Grown in Microgravity

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Mazuruk, K.

    2015-01-01

    Detached (or dewetted) Bridgman crystal growth defines that process in which a gap exists between a growing crystal and the crucible wall. In microgravity, the parameters that influence the existence of a stable gap are the growth angle of the solidifying crystal, the contact angle between the melt and the crucible wall, and the pressure difference across the meniscus. During actual crystal growth, the initial crystal radius will not have the precise value required for stable detached growth. Beginning with a crystal diameter that differs from stable conditions, numerical calculations are used to analyze the transient crystal growth process. Depending on the initial conditions and growth parameters, the crystal shape will either evolve towards attachment at the crucible wall, towards a stable gap width, or inwards towards eventual collapse of the meniscus. Dynamic growth stability is observed only when the sum of the growth and contact angles exceeds 180 degrees.

  9. Evaluation of metal trace detachment from dosing pumps using PIXE

    NASA Astrophysics Data System (ADS)

    Lozano, Omar; Mejia, Jorge; Laloy, Julie; Alpan, Lütfiye; Toussaint, Olivier; Dogné, Jean-Michel; Lucas, Stéphane

    2014-07-01

    Metal trace detachment evaluation is essential for instruments destined for pharmaceutical applications, such as pumps. Particle-Induced X-ray Emission (PIXE) was used to determine and quantify metal traces originated from stainless steel and ceramic dosing pumps. Metal traces were quantified from either distilled water samples or cellulose filters in two tests: a short-term test of 16 h mimicking a daily cycle of a dosing pump for industrial applications, and a long-term test of 9 days evaluating the pump wearing. The main result is that ceramic dosing pumps present lower metal detachment than stainless steel counterparts. Traces of Si and Al were found originating from pieces around the pumps (pipes and joints).

  10. Modeling of detachment experiments at DIII-D

    DOE PAGES

    Canik, John M.; Briesemeister, Alexis R.; Lasnier, C. J.; ...

    2014-11-26

    Edge fluid–plasma/kinetic–neutral modeling of well-diagnosed DIII-D experiments is performed in order to document in detail how well certain aspects of experimental measurements are reproduced within the model as the transition to detachment is approached. Results indicate, that at high densities near detachment onset, the poloidal temperature profile produced in the simulations agrees well with that measured in experiment. However, matching the heat flux in the model requires a significant increase in the radiated power compared to what is predicted using standard chemical sputtering rates. Lastly, these results suggest that the model is adequate to predict the divertor temperature, provided thatmore » the discrepancy in radiated power level can be resolved.« less

  11. Modeling of detachment experiments at DIII-D

    SciTech Connect

    Canik, John M.; Briesemeister, Alexis R.; Lasnier, C. J.; Leonard, A. W.; Lore, J. D.; McLean, A. G.; Watkins, J. G.

    2014-11-26

    Edge fluid–plasma/kinetic–neutral modeling of well-diagnosed DIII-D experiments is performed in order to document in detail how well certain aspects of experimental measurements are reproduced within the model as the transition to detachment is approached. Results indicate, that at high densities near detachment onset, the poloidal temperature profile produced in the simulations agrees well with that measured in experiment. However, matching the heat flux in the model requires a significant increase in the radiated power compared to what is predicted using standard chemical sputtering rates. Lastly, these results suggest that the model is adequate to predict the divertor temperature, provided that the discrepancy in radiated power level can be resolved.

  12. Abrupt tectonics and rapid slab detachment with grain damage.

    PubMed

    Bercovici, David; Schubert, Gerald; Ricard, Yanick

    2015-02-03

    A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relatively rapid slab detachment, i.e., within 1 My, depending on the size of the crustal plug. Thick continental crustal plugs can cause rapid necking while smaller plugs characteristic of ocean plateaux cause slower necking; oceanic lithosphere with normal or slightly thickened crust subducts without necking. The model potentially explains how large plateaux or continental crust drawn into subduction zones can cause slab loss and rapid changes in plate motion and/or induce abrupt continental rebound.

  13. Rhegmatogenous retinal detachment in morning glory syndrome pathogenesis and treatment.

    PubMed

    Ho, C L; Wei, L C

    2001-01-01

    We report a case of morning glory syndrome with retinal detachment. A slit-like retinal break at the edge of the excavated disc anomaly provided a direct communication between the subretinal space and the vitreous cavity. Retinal reattachment and useful vision was achieved after a single procedure of vitrectomy and gas tamponade. We believe that identification of the retinal break, removal of epipapillary fibroglial tissue and its traction force, the avoidance of perfluorocarbon liquid and the appropriate use of long-acting gas as endotamponade, all contributed to the favorable outcome. This is more evidence supporting the rhegmatogenous theory of retinal detachment in morning glory syndrome. A literature review of the clinical presentations and treatments of similar cases is included.

  14. Abrupt tectonics and rapid slab detachment with grain damage

    PubMed Central

    Bercovici, David; Schubert, Gerald; Ricard, Yanick

    2015-01-01

    A simple model for necking and detachment of subducting slabs is developed to include the coupling between grain-sensitive rheology and grain-size evolution with damage. Necking is triggered by thickened buoyant crust entrained into a subduction zone, in which case grain damage accelerates necking and allows for relatively rapid slab detachment, i.e., within 1 My, depending on the size of the crustal plug. Thick continental crustal plugs can cause rapid necking while smaller plugs characteristic of ocean plateaux cause slower necking; oceanic lithosphere with normal or slightly thickened crust subducts without necking. The model potentially explains how large plateaux or continental crust drawn into subduction zones can cause slab loss and rapid changes in plate motion and/or induce abrupt continental rebound. PMID:25605890

  15. Pneumoretinopexy in the treatment of retinal detachment with macular hole.

    PubMed

    Menchini, U; Scialdone, A; Visconti, C; Brancato, R

    1988-01-01

    Nine eyes of nine patients affected by retinal detachment with macular hole were treated with pneumoretinopexy and postoperative positioning. All the eyes were myopic (mean 13.3 d., sd 3.3), two were amblyopic and one was aphakic. The operative technique included eye softening and intravitreal SF6 gas injection only. Barrage laser photocoagulation was carried out after retinal reattachment. In seven eyes (77.8%) the retina reattached in a mean of three days and the visual acuity improved. No recurrences were observed after a mean of 11.6 months. No severe complications occurred. Vitreous flare was present in 44% and increase of floaters in 55% of the eyes. We believe that pneumoretinopexy can be employed as the first treatment in case of myopic retinal detachment with macular hole.

  16. Intellectual property rights and detached human body parts.

    PubMed

    Pila, Justine

    2014-01-01

    This paper responds to an invitation by the editors to consider whether the intellectual property (IP) regime suggests an appropriate model for protecting interests in detached human body parts. It begins by outlining the extent of existing IP protection for body parts in Europe, and the relevant strengths and weaknesses of the patent system in that regard. It then considers two further species of IP right of less obvious relevance. The first are the statutory rights of ownership conferred by domestic UK law in respect of employee inventions, and the second are the economic and moral rights recognised by European and international law in respect of authorial works. In the argument made, both of these species of IP right may suggest more appropriate models of sui generis protection for detached human body parts than patent rights because of their capacity better to accommodate the relevant public and private interests in respect of the same.

  17. Rapid Orbital Decay in Detached Binaries: Evidence for Circumbinary Disks

    NASA Astrophysics Data System (ADS)

    Chen, Wen-Cong; Podsiadlowski, Philipp

    2017-03-01

    Some short-period, detached binary systems have recently been reported as experiencing very rapid orbital decay, much faster than is expected from the angular-momentum loss caused by gravitational radiation alone. As these systems contain fully convective stars, magnetic braking is not believed to be operative, making the large orbital-period derivative puzzling. Here, we explore whether a resonant interaction between the binary and a surrounding circumbinary (CB) disk could account for the observed orbital decay. Our calculations indicate that the observed orbital-period derivatives in seven detached binaries can be produced by the resonant interaction between the binary and a CB disk if the latter has a mass in the range of {10}-4{--}{10}-2 {M}ȯ , which is of the same order as the inferred disk mass (∼ 2.4× {10}-4 {M}ȯ ) in the post-common-envelope binary NN Ser.

  18. Reflexivity and detachment: a discursive approach to women's depression.

    PubMed

    Crowe, Marie

    2002-06-01

    Reflexivity and detachment: a discursive approach to women's depression This paper explores a discursive approach to understanding women's depression by presenting the results of research into women's narratives of their experiences. The discursive approach taken acknowledges women's immersion in cultural practices that determine the subject positions available to them and places a value on attributes of reflexivity and detachment that are not usually associated with their performance. The social and cultural context of the individual's experience is significant because if the focus is simply on the individual this supposes that the problem lies solely with the individual. An understanding of cultural expectations and their relation to mental distress is important to mental health nursing practice. The psychotherapeutic relationship that is fundamental to mental health nursing practice requires an understanding of the meaning of individual's responses in their cultural context in order to provide facilitative and meaningful care for the women that they nurse.

  19. Detached Solidification of InSb on Earth

    NASA Technical Reports Server (NTRS)

    Wang, Jianbin; Regel, Liya L.; Wilcox, William R.

    2003-01-01

    Detached solidification of lightly gallium-doped indium antimonide was achieved in the laboratory only when the ampoule was coated with hexagonal boron nitride and when the material appeared to be oxide-free. A furnace was constructed with the temperature increasing with height in order to minimize bouyancy-driven convection, so as to maximize transport of segregated dissolved gases into the gap between the growing solid and the ampoule wall. There appeared to be no difference in results with freezing rates of 5 mmh and 10 mm/h. Best results were obtained when the ampoule was backfilled with 20 kPa of Ar-10%H2 prior to sealing. The detached portions were depressed by several pm from adjacent attached regions, were rough, and sometimes had microfacets and steps.

  20. Modeling detachment physics in the NSTX snowflake divertor

    NASA Astrophysics Data System (ADS)

    Meier, E. T.; Soukhanovskii, V. A.; Bell, R. E.; Diallo, A.; Kaita, R.; LeBlanc, B. P.; McLean, A. G.; Podestà, M.; Rognlien, T. D.; Scotti, F.

    2015-08-01

    The snowflake divertor is a proposed technique for coping with the tokamak power exhaust problem in next-step experiments and eventually reactors, where extreme power fluxes to material surfaces represent a leading technological and physics challenge. In lithium-conditioned National Spherical Torus Experiment (NSTX) discharges, application of the snowflake divertor typically induced partial outer divertor detachment and severalfold heat flux reduction. UEDGE is used to analyze and compare conventional and snowflake divertor configurations in NSTX. Matching experimental upstream profiles and divertor measurements in the snowflake requires target recycling of 0.97 vs. 0.91 in the conventional case, implying partial saturation of the lithium-based pumping mechanism. Density scans are performed to analyze the mechanisms that facilitate detachment in the snowflake, revealing that increased divertor volume provides most of the parallel heat flux reduction. Also, neutral gas power loss is magnified by the increased wetted area in the snowflake, and plays a key role in generating volumetric recombination.

  1. [Posterior vitreous detachment with collapse, and peripheral retinal degeneration in the aetiology of idiopathic retinal detachment. A synapsis of clinical observations and anatomical studies (author's transl)].

    PubMed

    Hruby, K

    1981-10-01

    The crucial aetiological factors of idiopathic retinal detachment are posterior vitreous detachment with collapse, and degenerative lesions in the fundus periphery. Posterior vitreous detachment does not imply diagnostic problems to the expert in this field. On the other hand, the peripheral retinal degenerations include wide range of lesions the clinical and pathoanatomical study of which has so far not resulted in a complete picture. The author of the present paper attempts to get closer to a clearly arranged classification and terminology of those peripheral retinal degenerations, which are of importance to the aetiology, prophylaxis and treatment of idiopathic retinal detachment.

  2. The Missing Magnetic WDs in Detached Close Binaries

    NASA Astrophysics Data System (ADS)

    Tovmassian, G.; Gonzalez-Buitrago, D.; Zharikov, S.

    2017-03-01

    A substantial fraction of isolated white dwarfs (WDs) are strongly magnetic. An even higher number of magnetic WDs are reported in cataclysmic variables (CVs). However, we have been struggling to find them in detached, close binaries. Recently, we identified a pair of such systems with K star companions. We suggest that we could not recognize them because they replicate CV behavior by fueling accretion onto the WD through the coupled magnetic fields of the WD and chromospherically active K star.

  3. Retinal dialysis and detachment in a child after airbag deployment.

    PubMed

    Eliott, Dean; Hauch, Adam; Kim, Rubin W; Fawzi, Amani

    2011-04-01

    A variety of airbag-associated ocular injuries have been reported in children sitting in the front passenger seat during automobile collisions. These injuries range from corneal abrasions to traumatic hyphema with secondary glaucoma and cataract. We report the case of a 5-year-old boy who experienced retinal dialysis and detachment associated with airbag deployment. The patient recovered 20/20 visual acuity after cryopexy and placement of a radial sponge.

  4. Detached cataclysmic variables are crossing the orbital period gap

    NASA Astrophysics Data System (ADS)

    Zorotovic, M.; Schreiber, M. R.; Parsons, S. G.; Gänsicke, B. T.; Hardy, A.; Agurto-Gangas, C.; Nebot Gómez-Morán, A.; Rebassa-Mansergas, A.; Schwope, A. D.

    2016-04-01

    A central hypothesis in the theory of cataclysmic variable (CV) evolution is the need to explain the observed lack of accreting systems in the ≃2-3 h orbital period range, known as the period gap. The standard model, disrupted magnetic braking (DMB), reproduces the gap by postulating that CVs transform into inconspicuous detached white dwarf (WD) plus main sequence systems, which no longer resemble CVs. However, observational evidence for this standard model is currently indirect and thus this scenario has attracted some criticism throughout the last decades. Here, we perform a simple but exceptionally strong test of the existence of detached CVs (dCVs). If the theory is correct, dCVs should produce a peak in the orbital period distribution of detached close binaries consisting of a WD and an M4-M6 secondary star. We measured six new periods which brings the sample of such binaries with known periods below 10 h to 52 systems. An increase of systems in the ≃2-3 h orbital period range is observed. Comparing this result with binary population models, we find that the observed peak cannot be reproduced by post-common envelope binaries (PCEBs) alone and that the existence of dCVs is needed to reproduce the observations. Also, the WD mass distribution in the gap shows evidence of two populations in this period range, i.e. PCEBs and more massive dCVs, which is not observed at longer periods. We therefore conclude that CVs are indeed crossing the gap as detached systems, which provides strong support for the DMB theory.

  5. Detachable connection for a nuclear reactor fuel assembly

    DOEpatents

    Christiansen, D.W.; Karnesky, R.A.

    1983-08-29

    A locking connection for releasably attaching a handling socket to the duct tube of a fuel assembly for a nuclear reactor. The connection comprises a load pad housing mechanically attached to the duct tube and a handling socket threadably secured within the housing. A retaining ring is interposed between the housing and the handling socket and is formed with a projection and depression engagable within a cavity and groove of the housing and handling socket, respectively, to form a detachable interlocked connection assembly.

  6. Detachable connection for a nuclear reactor fuel assembly

    DOEpatents

    Christiansen, David W.; Karnesky, Richard A.

    1986-01-01

    A locking connection for releasably attaching a handling socket to the duct tube of a fuel assembly for a nuclear reactor. The connection comprises a load pad housing mechanically attached to the duct tube and a handling socket threadably secured within the housing. A retaining ring is interposed between the housing and the handling socket and is formed with a projection and depression engageable within a cavity and groove of the housing and handling socket, respectively, to form a detachable interlocked connection assembly.

  7. Clinically undetected retinal breaks causing retinal detachment: options for management.

    PubMed

    Gupta, Deepak; Ching, Jared; Tornambe, Paul E

    2017-08-11

    The successful detection of retinal breaks is a critical step in rhegmatogenous retinal detachment (RRD) surgery in order to prevent persistent/recurrent RRDs. Not all retinal breaks causing retinal detachments are obvious. Retinal breaks may be obscured due to opacities that are either anterior-segment related, lens related or posterior-segment related. Rules to identify breaks based on sub-retinal fluid (SRF) configuration are more difficult to apply in pseudophakic, aphakic, encircled eyes, and eyes with repeat detachments and those with proliferative vitreoretinopathy (PVR). Exudative detachments exhibit characteristic features and must be ruled out. A thorough clinical examination pre-operatively is important even if a vitrectomy is planned. This paper reviews the incidence and causes of undetected breaks along with pre-operative/clinical issues that may hinder break detection. We review the literature with respect to investigative approaches and techniques that are available to the vitreo-retinal surgeon when primary breaks remains clinically undetected during the pre-operative examination. We broadly divide the surgical approaches into ones where the surgeon utilises techniques to actively pursue a search for breaks versus adopting a purely speculative approach. Advantages and disadvantages of various techniques are appraised. Intuitively one might argue that an encircling scleral buckle combined with vitrectomy would give higher single operation success than PPV alone because 'undetected' retinal breaks would be addressed by a 360° plombage. We could not confirm this concept. Newer techniques, such as PPV augmented with dye extrusion or endoscopic-assisted PPV show encouraging results. Technological advances such as intraoperative OCT will also help to broaden the VR surgeon's armamentarium. At this time there is no gold standard in terms of the recommended approach and this is reflected in the many options that are available for management in this

  8. Astrocyte Structural Reactivity and Plasticity in Models of Retinal Detachment

    PubMed Central

    Luna, Gabriel; Keeley, Patrick W.; Reese, Benjamin E.; Linberg, Kenneth A.; Lewis, Geoffrey P.; Fisher, Steven K.

    2016-01-01

    Although retinal neurodegenerative conditions such as age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and retinal detachment have different etiologies and pathological characteristics, they also have many responses in common at the cellular level, including neural and glial remodeling. Structural changes in Müller cells, the large radial glia of the retina in retinal disease and injury have been well described, that of the retinal astrocytes remains less so. Using modern imaging technology to describe the structural remodeling of retinal astrocytes after retinal detachment is the focus of this paper. We present both a review of critical literature as well as novel work focusing on the responses of astrocytes following rhegmatogenous and serous retinal detachment. The mouse presents a convenient model system in which to study astrocyte reactivity since the Müller cell response is muted in comparison to other species thereby allowing better visualization of the astrocytes. We also show data from rat, cat, squirrel, and human retina demonstrating similarities and differences across species. Our data from immunolabeling and dye-filling experiments demonstrate previously undescribed morphological characteristics of normal astrocytes and changes induced by detachment. Astrocytes not only upregulate GFAP, but structurally remodel, becoming increasingly irregular in appearance, and often penetrating deep into neural retina. Understanding these responses, their consequences, and what drives them may prove to be an important component in improving visual outcome in a variety of therapeutic situations. Our data further supports the concept that astrocytes are important players in the retina’s overall response to injury and disease. PMID:27060374

  9. Astrocyte structural reactivity and plasticity in models of retinal detachment.

    PubMed

    Luna, Gabriel; Keeley, Patrick W; Reese, Benjamin E; Linberg, Kenneth A; Lewis, Geoffrey P; Fisher, Steven K

    2016-09-01

    Although retinal neurodegenerative conditions such as age-related macular degeneration, glaucoma, diabetic retinopathy, retinitis pigmentosa, and retinal detachment have different etiologies and pathological characteristics, they also have many responses in common at the cellular level, including neural and glial remodeling. Structural changes in Müller cells, the large radial glia of the retina in retinal disease and injury have been well described, that of the retinal astrocytes remains less so. Using modern imaging technology to describe the structural remodeling of retinal astrocytes after retinal detachment is the focus of this paper. We present both a review of critical literature as well as novel work focusing on the responses of astrocytes following rhegmatogenous and serous retinal detachment. The mouse presents a convenient model system in which to study astrocyte reactivity since the Mϋller cell response is muted in comparison to other species thereby allowing better visualization of the astrocytes. We also show data from rat, cat, squirrel, and human retina demonstrating similarities and differences across species. Our data from immunolabeling and dye-filling experiments demonstrate previously undescribed morphological characteristics of normal astrocytes and changes induced by detachment. Astrocytes not only upregulate GFAP, but structurally remodel, becoming increasingly irregular in appearance, and often penetrating deep into neural retina. Understanding these responses, their consequences, and what drives them may prove to be an important component in improving visual outcome in a variety of therapeutic situations. Our data further supports the concept that astrocytes are important players in the retina's overall response to injury and disease. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. A Promising Adjuvant to Detachable Coils for Cavernous Packing: Onyx

    PubMed Central

    Lv, X.; Jiang, C.; Li, Y.; Wu, Z.

    2009-01-01

    Summary Transvenous embolization of cavernous dural arteriovenous fistulae (CDAVFs) with Onyx has recently been reported. This study was undertaken to assess the value of Onyx in transvenous treatment of CDAVFs. We retrospectively reviewed 18 patients who underwent transvenous embolization for CDAVFs of Barrow Type D with detachable coils and Onyx at our institution over five years. Patients were divided into two groups: group A, patients who had been treated with detachable coils; group B, patients who had been treated with a combination of detachable coils and Onyx. The approach routes, angiographic results, complications and clinical outcome were assessed for both groups. Eighteen patients with CDAVFs of Barrow Type D were treated: nine women and nine men; mean age was 41.9 years. Eleven patients treated by 19 procedures of transvenous coiling belonged to group A. Seven patients treated by eight procedures of transvenous Onyx injection belonged to group B. The periprocedural complication rate associated with coiling for both groups was 18.2% vs 16.7% with Onyx. The duration of the procedure in both groups was 6.77±2.49 hours vs 3.75±1.63 hours with coiling vs Onyx, and the cost of Onyx was cheaper than coils. An excellent outcome was achieved in both groups: 90.9% vs 100% (group A vs group B). Our results associated with both modalities of CDAVFs treatment with clinical outcome show that transvenous embolization with Onyx is a safe alternative to detachable coils in the treatment of CDAVFs. However, more cases need to be evaluated. PMID:20465891

  11. The Mobile Obstacle Detachment of the Soviet Ground Forces.

    DTIC Science & Technology

    1980-06-01

    reproduced in whole or in part without permission of the Commander, US Army% Russian Institute, APO ,lew York 09053. This 6ocument has been cleared for...artificial obstacles is an integral part of modern ground force tactical operations. Obstacles of all types are used by forces for a wide variety of...overlooked or relegated to a posi- tion of relatively low importance. 3 Although the mobile obstacle detachment com- prises only a very small part of

  12. Antimicrobials Influence Bond Stiffness and Detachment of Oral Bacteria.

    PubMed

    Song, L; Hou, J; van der Mei, H C; Veeregowda, D H; Busscher, H J; Sjollema, J

    2016-07-01

    Oral biofilm can never be fully removed by oral hygiene measures. Biofilm left behind after brushing is often left behind on the same sites and exposed multiple times to antimicrobials from toothpastes and mouthrinses, after which removal becomes increasingly difficult. On the basis of this observation, we hypothesize that oral bacteria adhering to salivary conditioning films become more difficult to remove after adsorption of antimicrobials due to stiffening of their adhesive bond. To verify this hypothesis, bacteria adhering to bare and saliva-coated glass were exposed to 3 different mouthrinses, containing chlorhexidine-digluconate, cetylpyridinium-chloride, or amine-fluoride, after which bacterial vibration spectroscopy was carried out or a liquid-air interface was passed over the adhering bacteria to stimulate their detachment. Brownian motion-induced nanoscopic vibration amplitudes of 4 oral streptococcal strains, reflecting their bond stiffness, decreased after exposure to mouthrinses. Concurrently, the percentage detachment of adhering bacteria upon the passage of a liquid-air interface decreased after exposure to mouthrinses. A buffer control left both vibration amplitudes and detachment percentages unaffected. Exposure to either of the selected mouthrinses yielded more positively charged bacteria by particulate microelectrophoresis, suggesting antimicrobial adsorption to bacterial cell surface components. To rule out that exposure of adhering bacteria to the mouthrinses stimulated polysaccharide production with an impact on their detachment, Fourier transform infrared spectroscopy was carried out on bacteria adhering to an internal reflection element, prior to and after exposure to the mouthrinses. Infrared absorption band areas indicated no significant change in amount of polysaccharides after exposure of adhering bacteria to mouthrinses, but wave number shifts demonstrated stiffening of polysaccharides in the bond, as a result of antimicrobial

  13. Collisional Detachment of Anions using Fourier Transform Mass Spectrometry

    DTIC Science & Technology

    1992-12-01

    results from the crossing of covalent and ionic potential energy surfaces. In accordance with the Landau - Zener [143] relation, the crossing is adiabatic...Charge transfer and associative detachment (Reactions (d) and (f)) are precluded for the rare gas targets. Landau and Zener [1431 have shown the...Illinois: Wolfram Research, Inc, 1990. 143. Zener , Clarence. "Non-Adiabatic Crossing of Energy Levels," Proceedings of the Royal Society of London, A137:696

  14. On the W7-X divertor performance under detached conditions

    NASA Astrophysics Data System (ADS)

    Feng, Y.; Beidler, C. D.; Geiger, J.; Helander, P.; Hölbe, H.; Maassberg, H.; Turkin, Y.; Reiter, D.; W7-X Team

    2016-12-01

    We present a theoretical/numerical predictive analysis of the performance of the W7-X island divertor under conditions of detachment characterized by intensive radiation. The analysis is based on EMC3-Eirene simulations and the earlier W7-AS experimental and numerical experience. Carbon is employed as a representative radiator. The associated drawbacks, i.e. core contamination and recycling degradation (reduced recycling flux), are evaluated by determining the carbon density at the last closed flux surface (LCFS) and the neutral pressure in the divertor chamber. Optimum conditions are explored in both configuration and plasma parameter space. This study aims to identify the key geometric/magnetic and plasma parameters that affect the performance of detached plasmas in W7-X. Emphasis is placed on what occurs when the islands are enlarged far beyond the maximum size available in W7-AS and whether an island size limit for optimal detachment operation exists, and why. Further issues addressed are the power removal ability of the W7-X edge islands, potentially limiting factors, compatibility between particle and power exhaust, and particle refueling capability of the recycling neutrals.

  15. Electron attachment and detachment: C6F6

    NASA Astrophysics Data System (ADS)

    Miller, Thomas M.; van Doren, Jane M.; Viggiano, A. A.

    2004-04-01

    Electron attachment to C6F6 is especially interesting because of the large change in symmetry between the neutral (D6h) and anion (C2v). We have made measurements of rate constants for electron attachment to C6F6 and thermal electron detachment from the parent anion, C6F6-, over the temperature range 297-400 K, in 133 Pa of He gas. A flowing-afterglow Langmuir probe (FALP) apparatus was used for this work. At 298 K, the electron attachment rate constant is ka=8.6+/-3.0×10-8 cm3 s-1, and the detachment rate constant kd is approximately 35 s-1. As the temperature increases kd increases rapidly, to about 3000 s-1 at 400 K. The attachment/detachment equilibrium implies that the electron affinity of C6F6 is 0.53+/-0.05 eV. Density functional calculations were carried out in order to obtain thermal quantities needed to convert the equilibrium constant ka/kd into EA(C6F6). G3(MP2) calculations yielded an electron affinity of 0.454 eV. The fluoride affinity of C6F6 was calculated to be 1.26 eV at 298 K using this same method. We expect the G3(MP2) results to be good within 0.1 eV.

  16. Activation of autophagy in photoreceptor necroptosis after experimental retinal detachment

    PubMed Central

    Dong, Kai; Zhu, Zi-Cheng; Wang, Feng-Hua; Ke, Gen-Jie; Yu, Zhang; Xu, Xun

    2014-01-01

    AIM To investigate whether photoreceptor necroptosis induced by z-VAD-FMK (pan caspase inhibitor) was involved the activation of autophagy and whether Necrostatin-1, a specific necroptosis inhibitor, could inhibit this induction of autophagy after experimental retinal detachment. METHODS Experimental retinal detachment models were created in Sprague-Dawley rats by subretinal injection of sodium hyaluronate and subretinal injections of z-VAD-FMK, vehicle or z-VAD-FMK plus Necrostatin-1. Three days after retinal detachment, morphologic changes were observed by transmission electron microscopy. In other animals, retinas were subjected to immunoprecipitation and Western Blotting, then probed with anti-RIP1, phosphoserine, LC-3II or caspase 8 antibody. RESULTS It was proved by immunoprecipitation and western blotting, that photoreceptor necroptosis was mediated by caspase-8 inhibition and receptor interacting protein kinase (RIP1) phosphorylation activation. Transmission electron microscope and western blotting results indicated that photoreceptor necroptosis was involved the LC-3II and autophagosomes induction. We also discovered Necrostatin-1 could inhibit RIP1 phosphorylation and LC-3II induction. CONCLUSION These data firstly indicate photoreceptor necroptosis is associated with the activation of autophagy. Necrostatin-1 protects photoreceptors from necroptosis and autophagy by down-regulation of RIP1 phosphorylation and LC-3II. PMID:25349786

  17. Physics of Coanda jet detachment at high-pressure ratio

    NASA Astrophysics Data System (ADS)

    Cornelius, Kenneth C.; Lucius, Gerald A.

    1994-05-01

    Experimental measurements of surface pressure for an underexpanded two-dimensional supersonic Coanda flow with static conditions exterior to the jet flow was obtained for a fixed slot height to a radius ratio of 0.04. The data demonstrate that an oblique shock forms near the jet exit plane which vectors the jet flow from the curved surface at a pressure ratio of 7.6. The jet detachment occurs at a pressure ratio which is a function of the ratio of slot height to cylinder radius. An increase in the pressure ratio to 11.5 before jet detachment has been demonstrated by the translation of the upper wall providing for a converging-diverging geometry. The physics of the Coanda expansion and the jet detachment are qualitatively described using an optical schlieren system. A compressible inviscid model was derived analytically to demonstrate the variation in Mach number and surface pressure as a function of the geometric parameters with increasing pressure ratio.

  18. Particle detachment during hydraulic shock loads in granular media filtration.

    PubMed

    Kim, J K; Lawler, D F

    2006-01-01

    Particle breakthrough can occur by either the breakoff of previously captured particles (or flocs) or the direct passage of some influent particles through the filter. Filtration experiments were performed in a laboratory-scale filter using spherical glass beads with a diameter of 0.55 mm as collectors. A single type of particle suspension (Min-U-Sil 5) and three different destabilisation methods (pH control, alum and polymer destabilisation) were used to destabilise particles. The filtration velocity of 5 m/h was similar to that used in standard media filtration practice. To assess the possibility of particle detachment during normal filtration, a hydraulic shock load (20% increase of flow rate) was applied after 4 h of normal filtration. The magnitude of particle detachment was proportional to the particle size for non-Brownian particles. At the same time, less favourable particles, i.e. particles with larger surface charge, were easily detached during the hydraulic shock load. Therefore, proper particle destabilisation before filtration is crucial for maximum particle removal, as well as minimum particle breakthrough.

  19. Modeling of extinguishing ELMs in detached divertor plasmas

    NASA Astrophysics Data System (ADS)

    Pigarov, A.; Krasheninnikov, S.; Hollmann, E.; Rognlien, T.

    2015-11-01

    Detached plasmas, the primary operational regime for divertors in next-step fusion devices, should be compatible with both good H-mode confinement and relatively small ELMs providing tolerable heat power loads on divertor targets. Here, dynamics of boundary plasma, impurities and material walls over a sequence of many type-I ELM events under detached divertor plasma conditions is studied with UEGDE-MB-W, the newest version of 2D edge plasma transport code, which incorporates Macro-Blob (MB) approach to simulate non-diffusive filamentary transport and various ``Wall'' (W) models for time-dependent hydrogen wall inventory and recycling. We present the results of multi-parametric analysis on the impact of the size and frequency of ELMs on the divertor plasma parameters where we vary the MB characteristics under different pedestals and divertor configurations. We discuss the conditions, under which small but frequent type-I ELMs (typical for high-power H-mode discharges on current tokamaks with hard deuterium gas puff) are not ``burning through'' the formed detached divertor plasma. In this case, the inner and outer divertors are filled by sub-eV, recombining, highly-impure plasma. Variations of impurity plasma content, radiation pattern, and deuterium wall inventory over the ELM cycle are analyzed. UEDGE-MB-W modeling results are compared to available experimental data.

  20. Timing and Outcomes of Vitreoretinal Surgery after Traumatic Retinal Detachment

    PubMed Central

    Orban, Molly

    2016-01-01

    Traumatic retinal detachments are a significant cause of morbidity. There are currently no evidence-based guidelines on the appropriate time to perform vitreoretinal surgery to repair a traumatic retinal detachment. Early intervention, within seven days of the inciting trauma, may decrease proliferative vitreoretinopathy and postoperative endophthalmitis. Later intervention may yield a reduced risk of inflammation and hemorrhage, particularly in cases of concomitant open globe injuries. This article reviews the literature on the management of retinal detachments associated with ocular trauma from the years 2006 to 2016. Particular focus was placed on the timing of surgery, concomitant open globe injury, anatomical success rates, visual acuity, and complication rates. In this review, anatomical success was not significantly related to timing of intervention when compared between early and delayed intervention in eyes with and without concomitant open globe injuries. Visual acuities postoperatively varied widely despite timing of intervention due to the large variation in mechanism and extent of ocular injuries. Proliferative vitreoretinopathy was a common complication. Preliminary data indicate that endophthalmitis rates may be lower when early vitreoretinal surgery is performed. There is insufficient data to conclude whether early or delayed surgery leads to improved outcomes, highlighting the need for further research in this domain. PMID:27999681

  1. Compatibility of Detached Divertor Operation with Robust Edge Pedestal Performance

    NASA Astrophysics Data System (ADS)

    Leonard, A. W.; Osborne, T. H.; Snyder, P. B.; Makowski, M. A.; McLean, A. G.

    2014-10-01

    The compatibility of radiative detached divertor operation with the maintenance of a robust H-mode pedestal is examined in DIII-D. A density scan with deuterium injection into H-mode spanned a range of divertor conditions from fully attached, ~30 eV at the target, with little divertor radiation to a fully detached with Te < 5 eV throughout the divertor up to the X-point. Over this scan of pedestal density from n /nGW = 30% to 60% the pedestal Te was reduced from 800 eV to 350 eV, representing a ~20% reduction in pedestal pressure with a similar reduction in normalized energy confinement. The reduction in pedestal pressure at high density was found to be consistent with a reduced pedestal ELM MHD stability limit at high collisionality. The scaling of the pedestal top pressure with density was also consistent with the EPED model, which assumes an additional constraint on the local pressure gradient. The MHD stability limit at the highest collisionality depends on details of the ELM instability growth rate normalization. This result is encouraging for future burning plasmas where a low collisionality pedestal is expected to be maintained even for high density detached divertor operation. Work supported by the US DOE under DE-FC02-04ER54698 and DE-AC52-07NA27344.

  2. Farnesol induces cell detachment from established S. epidermidis biofilms.

    PubMed

    Cerca, Nuno; Gomes, Fernanda; Bento, Joana C; França, Angela; Rolo, Joana; Miragaia, Maria; Teixeira, Pilar; Oliveira, Rosário

    2013-05-01

    Antibiotic resistance is a serious problem in Staphylococcus epidermidis infections as many clinical isolates of this organism are resistant to up to eight different antibiotics. The increased resistance to conventional antibiotic therapy has lead to the search for new antimicrobial therapeutic agents. Farnesol, an essential oil found in many plants, has been shown to be active against S. epidermidis. Using a type control strain we recently described that although farnesol was not efficient at killing biofilm bacteria, a strong reduction on biofilm biomass was detected, and we hypothesize that farnesol could, somehow, induce biofilm detachment. In this report, to test our hypothesis we used 36 representative clinical strains of S. epidermidis from different geographic locations and characterized them in terms of genetic variability by multilocus sequence typing and staphylococcal chromosome cassette mec. Strains were tested for biofilm formation, and the presence of ica, bhp and aap genes was determined. Stronger biofilms had always the presence of ica operon but often co-harbored bhp and aap genes. Farnesol was then used in biofilm-forming strains, and biofilm detachment was detected in half of the strains tested. Furthermore, we also showed that farnesol inability to kill biofilm bacteria was not the result of the biofilm structure but was related to high cell density. Our results demonstrate, for the first time, that the biomass reduction previously found by us, and many other groups, is the result not of cell killing but instead is the result of biofilm detachment.

  3. Computation of particle detachment from floors due to human walking

    NASA Astrophysics Data System (ADS)

    Elhadidi, Basman; Khalifa, Ezzat

    2005-11-01

    A computational model for detachment of fine particles due to the unsteady flow under a foot is developed. As the foot approaches the floor, fluid volume is displaced laterally as a wall jet from the perimeter of the contact area at high velocity and acceleration. Unsteady aerodynamic forces on particles attached to the floor are considered. Results show that the jet velocity is ˜40 m/s for a foot idealized as a 15 cm circular disk approaching the floor at 1 m/s with a final gap of 0.8 mm. This velocity is sufficient to detach small particles (1˜μm). The flow accelerates at ˜400 m/s^2 which affects the detachment of larger sized particles (˜100 μm). As the disk is brought to rest, the unsteady jet expands outwards, advecting a vortex ring closely attached to it. At the disk edge, a counter rotating vortex is generated by the sudden deceleration of the disk. Both vortices can play a role in entrainment of the suspended particles in the flowfield. Numerical studies also show that the maximum jet velocity is ˜20 m/s for a simplified foot immediately after heel contact in the stance phase of the gait.

  4. Detachment, compartmentalization, and schizophrenia: linking dissociation and psychosis by subtype.

    PubMed

    Vogel, Matthias; Braungardt, Tanja; Grabe, Hans Jörgen; Schneider, Wolfgang; Klauer, Thomas

    2013-01-01

    To explain the phenomenological overlap between dissociation and schizophrenia, a dissociative subtype of schizophrenia has been proposed as a possibility. Dissociation is often believed to be organized on a continuum, although 2 qualitatively different phenomena can be distinguished in theory, research, and clinical practice: (a) states of separation from self or environment (detachment dissociation) and (b) inaccessibility of normally accessible mental contents (compartmentalization dissociation). This study used the Positive and Negative Syndrome Scale (PANSS) and the Association for Methodology and Documentation in Psychiatry module for the interview assessment of dissociation to investigate the relationships between PANSS subscales, detachment dissociation, and compartmentalization dissociation in a sample of 72 patients with schizophrenia. A confirmatory factor analysis sustained the bipartite model, yielding factors that grouped dissociative items around amnesia and depersonalization/derealization. The latter factor also contained identity disturbances and was therefore not entirely consistent with the theoretical formulations of detachment dissociation. It is important to note that the structure of those factors may be influenced by the symptoms of schizophrenia to which they were specifically linked: The factor containing depersonalization/derealization was connected to the positive symptoms subscale of the PANSS, whereas the factor containing amnesia was associated with the negative subscale. Hence, a dichotomy of dissociation is confirmed inasmuch as its subtypes are as distinguishable as PANSS subscales. This has implications on theoretical and clinical levels.

  5. Electron detachment and relaxation of OH-(aq).

    PubMed

    Petersen, Christian; Thøgersen, Jan; Jensen, Svend Knak; Keiding, Søren R

    2007-11-15

    Femtosecond transient absorption spectroscopy is used to study the primary reaction dynamics of photoinduced electron detachment of the hydroxide ion in water, OH- (aq). The electron is detached by excitation of OH- (aq) to the charge-transfer-to-solvent (CTTS) state at 200 nm. The subsequent relaxation processes are probed in the spectral range from 193 to 800 nm with femtosecond time resolution. We determine both the time-dependent quantum yields of OH- (aq), OH(aq), and e-(aq), and we observe a transient spectral signature which is assigned to relaxation of hot (OH-)* ions formed via solvent-assisted conversion of the excited CTTS state to OH-. The primary quantum yield of OH(aq) is 65 +/- 5%, while recombination with e-(aq) reduces the yield to 34% after 5 ps and 12% after 200 ps. The yield of hot (OH-)* ions is 35 +/- 5%. Rotational anisotropy measurements of OH- (aq) and OH(aq) indicate a reorientation time for OH- (aq) of 1.9 ps, while no rotational anisotropy is resolved for the OH(aq) radical within our time resolution of 0.3 ps. This is consistent with the notion that OH(aq) radicals formed after electron detachment are only weakly bound to the hydrogen bond network of water. The assignment of the experimental data is supported by a series of electronic structure calculations of simple complexes of OH- (H(2)O)(n).

  6. Retinal Detachment in Down Syndrome: Characteristics and Surgical Outcomes

    PubMed Central

    AlAhmadi, Badr O.; Alsulaiman, Sulaiman M.; Arevalo, J. Fernando

    2016-01-01

    Purpose. To determine the functional and anatomic outcomes of rhegmatogenous retinal detachment (RRD) surgery in patients with Down syndrome. Methods. A retrospective chart review was performed of patients with Down syndrome who had undergone surgery for RRD at King Khalid Eye Specialist Hospital between 1995 and 2014. Results. A total of 245 patients with Down syndrome were evaluated during the study period. Eighteen eyes of 15 patients (6.1%) with RRD were identified. Three out of 15 patients (20%) presented with bilateral retinal detachment. All eyes presented with macula off retinal detachment. The retina was successfully reattached in 16/18 (88.8%) eyes after a mean follow-up of 48 months. The final postoperative visual acuity ranged from light perception to 20/125 (median: hand motion) (11/18 eyes). Conclusions. The anatomic success rate of retinal reattachment surgery in patients with Down syndrome is comparable to the general population. Patients with Down syndrome should undergo regular ophthalmic examinations for early diagnosis. Despite late diagnosis and the presence of proliferative vitreoretinopathy (PVR) in some patients, favorable anatomical outcomes can be achieved. PMID:27123341

  7. Happy, healthy, and productive: the role of detachment from work during nonwork time.

    PubMed

    Fritz, Charlotte; Yankelevich, Maya; Zarubin, Anna; Barger, Patricia

    2010-09-01

    Mentally distancing oneself from work during nonwork time can help restore resources lost because of work demands. In this study, we examined possible outcomes of such psychological detachment from work, specifically well-being and job performance. Although employees may need to mentally detach from work to restore their well-being, high levels of detachment may require a longer time to get back into "working mode," which may be negatively associated with job performance. Our results indicate that higher levels of self-reported detachment were associated with higher levels of significant other-reported life satisfaction as well as lower levels of emotional exhaustion. In addition, we found curvilinear relationships between psychological detachment and coworker reported job performance (task performance and proactive behavior). Thus, although high psychological detachment may enhance employee well-being, it seems that medium levels of detachment are most beneficial for job performance.

  8. Identification of Potential Biomarkers for Rhegmatogenous Retinal Detachment Associated with Choroidal Detachment by Vitreous iTRAQ-Based Proteomic Profiling

    PubMed Central

    Wu, Zhifeng; Ding, Nannan; Yu, Mengxi; Wang, Ke; Luo, Shasha; Zou, Wenjun; Zhou, Ying; Yan, Biao; Jiang, Qin

    2016-01-01

    Rhegmatogenous retinal detachment associated with choroidal detachment (RRDCD) is a complicated and serious type of rhegmatogenous retinal detachment (RRD). In this study, we identified differentially expressed proteins in the vitreous humors of RRDCD and RRD using isobaric tags for relative and absolute quantitation (iTRAQ) combined with nano-liquid chromatography-electrospray ion trap-mass spectrometry-mass spectrometry (nano-LC-ESI-MS/MS) and bioinformatic analysis. Our result shows that 103 differentially expressed proteins, including 54 up-regulated and 49 down-regulated proteins were identified in RRDCD. Gene ontology (GO) analysis suggested that most of the differentially expressed proteins were extracellular.The Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis suggested that proteins related to complement and coagulation cascades were significantly enriched. iTRAQ-based proteomic profiling reveals that complement and coagulation cascades and inflammation may play important roles in the pathogenesis of RRDCD. This study may provide novel insights into the pathogenesis of RRDCD and offer potential opportunities for the diagnosis and treatment of RRDCD. PMID:27941623

  9. Strategy for the management of uncomplicated retinal detachments: the European vitreo-retinal society retinal detachment study report 1.

    PubMed

    Adelman, Ron A; Parnes, Aaron J; Ducournau, Didier

    2013-09-01

    To study success and failure in the treatment of uncomplicated rhegmatogenous retinal detachments (RRDs). Nonrandomized, multicenter retrospective study. One hundred seventy-six surgeons from 48 countries spanning 5 continents provided information on the primary procedures for 7678 cases of RRDs including 4179 patients with uncomplicated RRDs. Reported data included specific clinical findings, the method of repair, and the outcome after intervention. Final failure of retinal detachment repair (level 1 failure rate), remaining silicone oil at the study's conclusion (level 2 failure rate), and need for additional procedures to repair the detachment (level 3 failure rate). Four thousand one hundred seventy-nine uncomplicated cases of RRD were included. Combining phakic, pseudophakic, and aphakic groups, those treated with scleral buckle alone (n = 1341) had a significantly lower final failure rate than those treated with vitrectomy, with or without a supplemental buckle (n = 2723; P = 0.04). In phakic patients, final failure rate was lower in the scleral buckle group compared with those who had vitrectomy, with or without a supplemental buckle (P = 0.028). In pseudophakic patients, the failure rate of the initial procedure was lower in the vitrectomy group compared with the scleral buckle group (P = 3×10(-8)). There was no statistically significant difference in failure rate between segmental (n = 721) and encircling (n = 351) buckles (P = 0.5). Those who underwent vitrectomy with a supplemental scleral buckle (n = 488) had an increased failure rate compared with those who underwent vitrectomy alone (n = 2235; P = 0.048). Pneumatic retinopexy was found to be comparable with scleral buckle when a retinal hole was present (P = 0.65), but not in cases with a flap tear (P = 0.034). In the treatment of uncomplicated phakic retinal detachments, repair using scleral buckle may be a good option. There was no significant difference between segmental versus 360-degree buckle

  10. The role of partners and children for employees' psychological detachment from work and well-being.

    PubMed

    Hahn, Verena C; Dormann, Christian

    2013-01-01

    This study examined the role of partners and children for employees' psychological detachment from work during off-job time. Building on boundary theory, we hypothesized that not only employees' own work-home segmentation preference but also their partners' work-home segmentation preference is associated with employees' psychological detachment. In addition, partners' psychological detachment should influence employees' psychological detachment. We hypothesized that the presence of children in the household moderates partners' influence on employees' psychological detachment. Further, we expected both employees' and their partners' psychological detachment to contribute to employees' well-being. Participants were 114 dual-earner couples who responded to Web-based questionnaires. The hypotheses were tested with multilevel analyses, using the actor-partner interdependence model. Results confirmed our hypotheses. Employees' and their partners' work-home segmentation preferences were associated with employees' psychological detachment. The presence of children moderated the relation between partners' work-home segmentation preference and employees' psychological detachment. The relation was weaker when there were children in the household. Moreover, employees' and their partners' psychological detachment were positively associated. Again, the relation was weaker when there were children in the household. Finally, both employees' and their partners' psychological detachment contributed to employees' well-being.

  11. Slab Detachment Under the Eastern Alps Seen By Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Qorbani, E.; Bianchi, I.; Bokelmann, G.

    2014-12-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian-Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW-NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW-SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW-SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle.

  12. Slab detachment under the Eastern Alps seen by seismic anisotropy

    NASA Astrophysics Data System (ADS)

    Qorbani, Ehsan; Bianchi, Irene; Bokelmann, Götz

    2015-04-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian-Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW-NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW-SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW-SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle.

  13. Choroidal detachment in perforated corneal ulcers: frequency and management

    PubMed Central

    Singh, R; Umapathy, T; Abedin, A; Eatamadi, H; Maharajan, S; Dua, H S

    2006-01-01

    Aims To determine the frequency of choroidal detachment (CD) in eyes with non‐traumatic corneal ulcer perforation and, also, to assess the efficacy and safety of cyanoacrylate glue in sealing corneal perforations. Methods 18 eyes of 17 patients were studied. Inclusion criterion was any patient with a non‐traumatic perforated corneal ulcer. All patients had a thorough history taken and complete ophthalmic examination including B‐scan ultrasonography. Patient demographics, presence of CD, and efficacy of corneal gluing were assessed. Results Eight of the 18 eyes (44%) were documented to have a CD. Among perforations of >2 mm2, six eyes (75%) were documented to have CD compared with two eyes (20%) with perforations of ⩽2 mm2 (p = 0.054). No correlation could be determined between perforation duration and incidence of CD. Of the 15 eyes that underwent gluing, there were 13 successes (87%) and two failures (13%). Within the successes four patients (27%) required re‐gluing because of infection (one patient) or progression of melt and glue loosening (three patients). Failure was the result of severe progression of melting (one patient) and a very large perforation (one patient). Conclusion Choroidal detachment following corneal ulcer perforation is common and is more likely in larger corneal perforations. Preoperative B‐scan should be considered in cases of large corneal perforations requiring therapeutic keratoplasty to document choroidal detachment, which if large may require drainage. Cyanoacrylate glue is an effective and safe method for sealing small corneal perforations. A vigil must be maintained for infection while the glue and bandage contact lens are in situ. PMID:16723362

  14. Middle Miocene Displacement Along the Rand Detachment Fault, Rand Mountains

    NASA Astrophysics Data System (ADS)

    Shulaker, D. Z.; Grove, M. J.

    2015-12-01

    Laramide flat-slab subduction extinguished Sierra Nevada pluton emplacement in southern California by ca. 85 Ma as trench-derived sediments were underthrust and accreted beneath arc basement. These relationships are well illustrated in the Rand Mountains, situated just south of the Garlock fault in the northwestern Mojave Desert. Here, accreted rocks within the Rand Mountains are referred to as Rand Schist. The Rand Detachment fault juxtaposes Rand Schist beneath 87 Ma Sierran granitoids. New zircon (U-Th)/He age results from schist and basement juxtaposed across the Rand Detachment fault are 15 ± 3 Ma and 30 ± 5 Ma, respectively. When considered within the context of previously reported thermochronology from the Rand Mountains, our data shows that the Rand Detachment fault in the Rand Mountains is a middle Miocene fault that facilitated extension of the northwest Mojave Desert. This timing is in temporal and spatial agreement with regional extension throughout the Mojave triggered by northern migration of the slab window after collision of the Mendocino Triple Junction with the southern California margin. Further evidence of slab-window-related magmatism in the easternmost Rand Mountains is provided by the 19 Ma Yellow Aster pluton and 19 Ma rhyolite porphyry. It is possible that Miocene extension re-activated an older structure within the Rand Mountains. For example, a similar low-angle fault juxtaposing schist and basement present in the San Emigdio Mountains is believed to have accommodated large scale Late Cretaceous displacement, exhuming Rand Schist and overlying deepest Sierran basement to shallow crustal levels by 77 Ma [1]. However, 68-72 Ma phengite cooling ages and other thermochronology from the Rand Mountains indicates that any pre-Miocene extension in this area must postdate that in the San Emigdio Mountains. [1] Chapman et al., 2012. Geosphere, 8, 314-341.

  15. Slab detachment under the Eastern Alps seen by seismic anisotropy

    NASA Astrophysics Data System (ADS)

    Qorbani, Ehsan; Bianchi, Irene; Bokelmann, Götz

    2015-01-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian-Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW-NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW-SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW-SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle.

  16. Staphylococcal Adhesion, Detachment and Transmission on Nanopillared Si Surfaces.

    PubMed

    Hizal, Ferdi; Choi, Chang-Hwan; Busscher, Henk J; van der Mei, Henny C

    2016-11-09

    Nanostructured surfaces are extensively considered with respect to their potential impact on bacterial adhesion from aqueous suspensions or air, but in real-life bacteria are often transmitted between surfaces. Mechanistically, transmission involves detachment of adhering bacteria from a donor and adhesion to a receiver surface, controlled by the relative values of the adhesion forces exerted by both surfaces. We here relate staphylococcal adhesion, detachment and transmission to, from, and between smooth and nanopillared-Si surfaces with staphylococcal adhesion forces. Nanopillared-Si surfaces were prepared with pillar-to-pillar distances of 200, 400, and 800 nm. On smooth surfaces, staphylococcal adhesion forces, measured using bacterial-probe Atomic-Force-Microscopy, amounted to 4.4-6.8 and 1.8-2.1 nN (depending on the AFM-loading force) for extracellular-polymeric-substances (EPS) producing and non-EPS producing strains, respectively. Accordingly the EPS producing strain adhered in higher numbers than the non-EPS producing strain. Fractional adhesion forces on nanopillared-Si surfaces relative to the smooth surface ranged from 0.30 to 0.95, depending on AFM-loading force, strain and pillar-to-pillar distance. However, for each strain, the number of adhering bacteria remained similar on all nanopillared surfaces. Detachment of adhering staphylococci decreased significantly with increasing adhesion forces, while staphylococcal transmission to a receiver surface also decreased with increasing adhesion force exerted by the donor. In addition, the strain with ability to produce EPS was killed in high percentages and induced to produce EPS during transmission on nanopillared-Si surfaces, presumably by high local cell-wall stresses. This must be accounted for in applications of nanostructured surfaces: whereas killing may be favorable, EPS production may reduce antimicrobial efficacy.

  17. Slab detachment under the Eastern Alps seen by seismic anisotropy

    PubMed Central

    Qorbani, Ehsan; Bianchi, Irene; Bokelmann, Götz

    2015-01-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian–Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW–NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW–SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW–SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle. PMID:25843968

  18. Slab detachment under the Eastern Alps seen by seismic anisotropy.

    PubMed

    Qorbani, Ehsan; Bianchi, Irene; Bokelmann, Götz

    2015-01-01

    We analyze seismic anisotropy for the Eastern Alpine region by inspecting shear-wave splitting from SKS and SKKS phases. The Eastern Alpine region is characterized by a breakdown of the clear mountain-chain-parallel fast orientation pattern that has been previously documented for the Western Alps and for the western part of the Eastern Alps. The main interest of this paper is a more detailed analysis of the anisotropic character of the Eastern Alps, and the transition to the Carpathian-Pannonian region. SK(K)S splitting measurements reveal a rather remarkable lateral change in the anisotropy pattern from the west to the east of the Eastern Alps with a transition area at about 12°E. We also model the backazimuthal variation of the measurements by a vertical change of anisotropy. We find that the eastern part of the study area is characterized by the presence of two layers of anisotropy, where the deeper layer has characteristics similar to those of the Central Alps, in particular SW-NE fast orientations of anisotropic axes. We attribute the deeper layer to a detached slab from the European plate. Comparison with tomographic studies of the area indicates that the detached slab might possibly connect with the lithosphere that is still in place to the west of our study area, and may also connect with the slab graveyard to the East, at the depth of the upper mantle transition zone. On the other hand, the upper layer has NW-SE fast orientations coinciding with a low-velocity layer which is found above a more-or-less eastward dipping high-velocity body. The anisotropy of the upper layer shows large-scale NW-SE fast orientation, which is consistent with the presence of asthenospheric flow above the detached slab foundering into the deeper mantle.

  19. An Assessment of Molten Metal Detachment Hazards for Electron Beam Welding in the Space Environment: Analysis and Test Results

    NASA Technical Reports Server (NTRS)

    Nunes, A. C., Jr.; Russell, C.; Bhat, B.; Fragomeni, J. M.

    1998-01-01

    Conditions under which molten metal detachments might occur in a space welding environment are analyzed. A weld pool detachment parameter specifying conditions for pool detachment by impact is derived and corroborated by experimental evidence. Impact detachment for the pool is unlikely. Impact detachment for a drop of metal on the end of the weld wire may be possible under extreme conditions. Other potential causes of molten metal detachment considered, vaporization pressure forces and wire flickout from the pool, did not appear to present significant detachment threats.

  20. Young-Person's Guide to Detached-Eddy Simulation Grids

    NASA Technical Reports Server (NTRS)

    Spalart, Philippe R.; Streett, Craig (Technical Monitor)

    2001-01-01

    We give the "philosophy", fairly complete instructions, a sketch and examples of creating Detached-Eddy Simulation (DES) grids from simple to elaborate, with a priority on external flows. Although DES is not a zonal method, flow regions with widely different gridding requirements emerge, and should be accommodated as far as possible if a good use of grid points is to be made. This is not unique to DES. We brush on the time-step choice, on simple pitfalls, and on tools to estimate whether a simulation is well resolved.

  1. Residual Gas Effects on Detached Solidification in Microgravity

    NASA Technical Reports Server (NTRS)

    Regel, Liya L.; Wilcox, William R.; Ramakrishnan, Suresh; Kota, Arun

    2003-01-01

    Many microgravity directional solidification experiments yielded ingots with portions that grew without contacting the ampoule wall, leading to greatly improved crystallographic perfection. Our long-term goal is to make such detached solidification reproducible, which requires a full understanding of the mechanisms underlying it. Our Moving Meniscus Model of steady-state detachment predicts that it depends strongly on the surface tension of the melt and the advancing contact angle with the ampoule wall. Detached solidification is more likely when the contact angle for the melt on the ampoule wall is high, i.e. non-wetting. It has been claimed that impurities increase the contact angle. The objective of the current project is to determine the influence of residual gases on the surface tension and contact angle of molten semiconductors on typical ampoule materials. We are focusing on determining the influence of oxygen on the contact angle of molten InSb on clean silica ('quartz'), including the advancing and retreating contact angles in addition to the usual equilibrium contact angle. We have created a gas flow system that allows us to control the oxygen partial pressure over a sessile drop of InSb on a horizontal quartz surface. The cell is slowly tilted while videotaping to reveal the contact angles on the two sides of the drop just prior to it rolling down the surface. Thus far, we have learned the following: (1) Molten InSb readily forms an oxide layer in the presence of the trace amounts of oxygen found in high purity argon; (2) This oxide contains a substantial amount of Ga, which presumably is a trace contaminant that is not detectable in the starting material; (3) The addition of 10% hydrogen to the argon gas is sufficient to reduce the oxide and produce a clean drop; (4) An infrared filter must precede the video camera in order to produce a sharp image of the drop for later image analysis; (5) Tilting the surface on which the drop rests causes the two sides

  2. Tamponade in the surgical management of retinal detachment.

    PubMed

    Vaziri, Kamyar; Schwartz, Stephen G; Kishor, Krishna S; Flynn, Harry W

    2016-01-01

    Despite treatment advances, rhegmatogenous retinal detachment (RD) can have poor visual outcomes even with prompt and appropriate therapy. Pars plana vitrectomy is a leading management modality for the treatment of RD. This procedure is generally accompanied by the use of internal tamponade. Various gases and silicone oils may yield beneficial outcomes. Heavy silicone oils have been approved in some European nations but are not available in the USA. Different tamponade agents have unique benefits and risks, and choice of the agent should be individualized according to the characteristics of the patient and RD, as well as perioperative and postoperative factors.

  3. Hypovolemic shock due to giant uterus leiomyoma detachment.

    PubMed

    Galani, P; Kapetanakis, S; Papadopoulos, C; Dimitrakopoulou, G; Kosma, L; Lafoyianni, S; Dimitrakova, E; Papathanasiou, J; Fiska, A

    2010-01-01

    Uterine leiomyoma (UL) is the most common benign gynecologic tumor of the reproductive age females. It is symptomatic only in 25% of the patients causing dysmenorrhea, menorrhagia or anemia. In some patients it occurs just as a palpable abdominal mass. In this study, we report a 50-year-old woman with a giant mass, attached to the uterus, which was detached and therefore led to shock due to major hemorrhage. Surgical removal of both the mass and the uterus confirmed the diagnosis of a pedunculated uterine leiomyoma.

  4. Reduction of corneal sensitivity after retinal detachment surgery.

    PubMed Central

    Gibson, R A

    1981-01-01

    Corneal sensitivity measurements were performed on both eyes of 57 patients after they were subjected to unilateral retinal detachment surgery, the unoperated eyes acting as controls. A marked decrease in corneal sensitivity was found in eyes that were treated with encircling bands, but no significant change of sensitivity could be detected in eyes in which localised radial or circumferential silicone sponge explants alone had been employed. It would appear that encirclement procedures lower the sensitivity of the cornea, and this may continue as a long-term effect. PMID:7295628

  5. Proteomic Analysis of Elevated Intraocular Pressure with Retinal Detachment.

    PubMed

    Velez, Gabriel; Roybal, C Nathaniel; Binkley, Elaine; Bassuk, Alexander G; Tsang, Stephen H; Mahajan, Vinit B

    2017-04-01

    To report a case of elevated intraocular pressure with retinal detachment. Liquid chromatography and tandem mass spectrometry was performed on the patient aqueous biopsy. Protein levels were analyzed with 1-way analysis of variance (ANOVA) and unbiased clustering. High levels of rod outer segment proteins were not detected, suggesting that this was not a case of Schwartz-Matsuo syndrome. Instead, elevated levels of Hepcidin (HEPC) and Cystatin C (CYTC; candidate biomarkers for primary open angle glaucoma) were detected, suggesting a different, unknown etiology. Molecular diagnoses can differentiate between clinical diagnoses and point to common biomarkers or disease mechanisms.

  6. The disappearance and reappearance of Titan's detached haze layer

    NASA Astrophysics Data System (ADS)

    West, Robert; Rannou, Pascal; Lavvas, Panayotis; Seignovert, Benoit; Turtle, Elizabeth P.; Perry, Jason; Ovanessian, Aida; Roy, Mou

    2016-10-01

    Titan's extended haze is a prominent and long-lived feature of the atmosphere that encompasses a rich variety of chemical, dynamical and microphysical processes operating over a wide range of temporal and spatial scales. The so-called 'detached' haze layer is easily seen in high-resolution short-wave (near-UV and blue wavelengths) images and is a consequence of a nearly global (outside of the winter polar hood region) layer depleted in aerosol content. It was first seen near 350 Km altitude in Voyager images (Rages and Pollack, 1983) and later observed by the Cassini ISS cameras (Porco et al., 2005; West et al., 2010) and UV stellar occultation profiles (Koskinen et al. 2011). A series of Cassini images from 2009 to 2010 revealed what appears to be a seasonally related altitude variation with remarkable regularity (comparing the Voyager and Cassini images). The drop in altitude is most rapid at equinox. Here we report on images of the upper haze layer over the period 2012 to early 2016. In the early part of this period the detached haze continued to drop in altitude and disappeared. There was no evidence for it beginning late in 2012 and extending to early 2016 when it was again detected with very low contrast at an altitude near 500 Km. We document this behavior and examine the evolution of the haze as functions of both latitude and time. These new details put additional constraints on models that attempt to account for the existence of the detached layer. Part of this work was done by the Jet Propulsion Laboratory, California Institute of Technology. References: Rages, K., and J. B. Pollack (1983), Vertical distribution of scattering hazes in Titan's upper atmosphere, Icarus, 55, 50-62, doi:10.1016/0019-1035 (83)90049-0; Porco, C. C. et al., Imaging Titan from the Cassini Spacecraft, Nature 434, 159-168 (2005); West, R. A. et al., The evolution of Titans detached haze layer near equinox in 2009", Geophys. Res. Lett. 38, L06204, doi:10.1029/2011GL046843, 2011

  7. Tamponade in the surgical management of retinal detachment

    PubMed Central

    Vaziri, Kamyar; Schwartz, Stephen G; Kishor, Krishna S; Flynn, Harry W

    2016-01-01

    Despite treatment advances, rhegmatogenous retinal detachment (RD) can have poor visual outcomes even with prompt and appropriate therapy. Pars plana vitrectomy is a leading management modality for the treatment of RD. This procedure is generally accompanied by the use of internal tamponade. Various gases and silicone oils may yield beneficial outcomes. Heavy silicone oils have been approved in some European nations but are not available in the USA. Different tamponade agents have unique benefits and risks, and choice of the agent should be individualized according to the characteristics of the patient and RD, as well as perioperative and postoperative factors. PMID:27041988

  8. Clinical variables associated with failure of retinal detachment repair: the European vitreo-retinal society retinal detachment study report number 4.

    PubMed

    Adelman, Ron A; Parnes, Aaron J; Michalewska, Zofia; Ducournau, Didier

    2014-09-01

    To identify risk factors associated with failure of anatomic reattachment in primary rhegmatogenous retinal detachment repair. Nonrandomized, multicenter, collaborative study. Primary procedures for 7678 rhegmatogenous retinal detachments reported by 176 surgeons from 48 countries. We recorded specific preoperative clinical findings, repair method, and outcome after intervention. We performed univariate, bivariate, and multivariate analyses to identify variables associated with surgical failure. Final failure of retinal detachment repair (level 1), remaining silicone oil at study conclusion (level 2), and need for additional procedures to repair the detachment (level 3). We analyzed 7678 cases of rhegmatogenous retinal detachment repair. Presence of choroidal detachment or significant hypotony was associated with significantly higher level 1 failure rates when grade 0 or B proliferative vitreoretinopathy (PVR) was present and higher level 2 failure rates, regardless of PVR status (P<0.05). Excluding cases with choroidal detachment or hypotony, increasing PVR was associated with increasing level 1 failure rates. The difference between grade B and C-1 PVR was significant (P = 2 × 10(-6)). No difference was observed in level 1 failure rates when operated eyes were phakic versus pseudophakic. Level 1 failure was significantly higher when all 4 quadrants of retina (4.4%) were detached than when only 1 quadrant (0.8%) had subretinal fluid. With grade B or C-1 PVR, cases with large or giant tears had significantly higher level 1 failure rates. No association was observed between number of retinal breaks and failure rates. Multivariate analysis showed grade C-1 PVR, 4 detached quadrants, and presence of choroidal detachment or significant hypotony were independently linked with a greater level 1 failure rate; the presence of a smaller retinal break was associated with a lesser level 1 failure rate. Choroidal detachment, significant hypotony, grade C-1 PVR, 4 detached

  9. 2-Methoxy-4-vinylphenol can induce cell cycle arrest by blocking the hyper-phosphorylation of retinoblastoma protein in benzo[a]pyrene-treated NIH3T3 cells

    SciTech Connect

    Jeong, Jin Boo; Jeong, Hyung Jin

    2010-10-01

    Research highlights: {yields} 2M4VP activated the expression of p21 and p15 protein, and down-regulated the expression of cyclin D1 and cyclin E. {yields} 2M4VP inhibited hyper-phosphorylation of Rb protein. {yields} 2M4VP induced cell cycle arrest from G1 to S. {yields} 2M4VP inhibited hyper-proliferation of the cells in BaP-treated cells. {yields} 2M4VP induces growth arrest of BaP-treated cells by blocking hyper-phosphorylation of Rb via regulating the expression of cell cycle-related proteins. -- Abstract: Benzo[a]pyrene (BaP) is an environment carcinogen that can enhance cell proliferation by disturbing the signal transduction pathways in cell cycle regulation. In this study, the effects of 2M4VP on cell proliferation, cell cycle and cell cycle regulatory proteins were studied in BaP-treated NIH 3T3 cells to establish the molecular mechanisms of 2M4VP as anti-proliferative agents. 2M4VP exerted a dose-dependent inhibitory effect on cell growth correlated with a G1 arrest. Analysis of G1 cell cycle regulators expression revealed 2M4VP increased expression of CDK inhibitor, p21Waf1/Cip1 and p15 INK4b, decreased expression of cyclin D1 and cyclin E, and inhibited kinase activities of CDK4 and CDK2. However, 2M4VP did not affect the expression of CDK4 and CDK2. Also, 2M4VP inhibited the hyper-phosphorylation of Rb induced by BaP. Our results suggest that 2M4VP induce growth arrest of BaP-treated NIH 3T3 cells by blocking the hyper-phosphorylation of Rb via regulating the expression of cell cycle-related proteins.

  10. APP Deletion Accounts for Age-Dependent Changes in the Bioenergetic Metabolism and in Hyperphosphorylated CaMKII at Stimulated Hippocampal Presynaptic Active Zones.

    PubMed

    Laßek, Melanie; Weingarten, Jens; Wegner, Martin; Neupärtl, Moritz; Array, Tabiwang N; Harde, Eva; Beckert, Benedikt; Golghalyani, Vahid; Ackermann, Jörg; Koch, Ina; Müller, Ulrike C; Karas, Michael; Acker-Palmer, Amparo; Volknandt, Walter

    2017-01-01

    Synaptic release sites are characterized by exocytosis-competent synaptic vesicles tightly anchored to the presynaptic active zone (PAZ) whose proteome orchestrates the fast signaling events involved in synaptic vesicle cycle and plasticity. Allocation of the amyloid precursor protein (APP) to the PAZ proteome implicated a functional impact of APP in neuronal communication. In this study, we combined state-of-the-art proteomics, electrophysiology and bioinformatics to address protein abundance and functional changes at the native hippocampal PAZ in young and old APP-KO mice. We evaluated if APP deletion has an impact on the metabolic activity of presynaptic mitochondria. Furthermore, we quantified differences in the phosphorylation status after long-term-potentiation (LTP) induction at the purified native PAZ. We observed an increase in the phosphorylation of the signaling enzyme calmodulin-dependent kinase II (CaMKII) only in old APP-KO mice. During aging APP deletion is accompanied by a severe decrease in metabolic activity and hyperphosphorylation of CaMKII. This attributes an essential functional role to APP at hippocampal PAZ and putative molecular mechanisms underlying the age-dependent impairments in learning and memory in APP-KO mice.

  11. Hyperphosphorylation of Tau at Ser396 occurs in the much earlier stage than appearance of learning and memory disorders in 5XFAD mice.

    PubMed

    Kanno, Takeshi; Tsuchiya, Ayako; Nishizaki, Tomoyuki

    2014-11-01

    The present study investigated the relation of age-dependent spatial learning/memory impairment and Tau phosphorylation in 5XFAD mice, a model of Alzheimer's disease. In the water maze test, the acquisition and retention latencies for 5XFAD mice at 6 months, but not 2 months, of age was significantly longer than those for wild-type mice at the same months of age, without difference in the swim speed and visual acuity between two groups. The level of glycogen synthase kinase 3β (GSK-3β) phosphorylation at Ser9 in the hippocampus for the 5XFAD mice at >4 months of age was significantly lesser than that for wild-type mice at the same months of age, while a robust increase in the Tyr216 phosphorylation of GSK-3β was found both in wild-type and 5XFAD mice at 6 months of age, without no significant difference in the extent between two groups. There was no significant difference in the Tau phosphorylation at Ser202/Thr205 in the hippocampus between two groups, but Ser396 phosphorylation for 5XFAD mice was significantly higher than that for wild-type mice at ages ranging from 2 to 6 months. The results of the present study indicate that Tau hyperphosphorylation in the brain for 5XFAD mice precedes high activation of GSK-3β and occurs in the much earlier stage than appearance of learning and memory disorders. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. APP Deletion Accounts for Age-Dependent Changes in the Bioenergetic Metabolism and in Hyperphosphorylated CaMKII at Stimulated Hippocampal Presynaptic Active Zones

    PubMed Central

    Laßek, Melanie; Weingarten, Jens; Wegner, Martin; Neupärtl, Moritz; Array, Tabiwang N.; Harde, Eva; Beckert, Benedikt; Golghalyani, Vahid; Ackermann, Jörg; Koch, Ina; Müller, Ulrike C.; Karas, Michael; Acker-Palmer, Amparo; Volknandt, Walter

    2017-01-01

    Synaptic release sites are characterized by exocytosis-competent synaptic vesicles tightly anchored to the presynaptic active zone (PAZ) whose proteome orchestrates the fast signaling events involved in synaptic vesicle cycle and plasticity. Allocation of the amyloid precursor protein (APP) to the PAZ proteome implicated a functional impact of APP in neuronal communication. In this study, we combined state-of-the-art proteomics, electrophysiology and bioinformatics to address protein abundance and functional changes at the native hippocampal PAZ in young and old APP-KO mice. We evaluated if APP deletion has an impact on the metabolic activity of presynaptic mitochondria. Furthermore, we quantified differences in the phosphorylation status after long-term-potentiation (LTP) induction at the purified native PAZ. We observed an increase in the phosphorylation of the signaling enzyme calmodulin-dependent kinase II (CaMKII) only in old APP-KO mice. During aging APP deletion is accompanied by a severe decrease in metabolic activity and hyperphosphorylation of CaMKII. This attributes an essential functional role to APP at hippocampal PAZ and putative molecular mechanisms underlying the age-dependent impairments in learning and memory in APP-KO mice. PMID:28163681

  13. 5-HT(2C) serotonin receptor blockade prevents tau protein hyperphosphorylation and corrects the defect in hippocampal synaptic plasticity caused by a combination of environmental stressors in mice.

    PubMed

    Busceti, Carla Letizia; Di Pietro, Paola; Riozzi, Barbara; Traficante, Anna; Biagioni, Francesca; Nisticò, Robert; Fornai, Francesco; Battaglia, Giuseppe; Nicoletti, Ferdinando; Bruno, Valeria

    2015-09-01

    Exposure to multimodal sensory stressors is an everyday occurrence and sometimes becomes very intense, such as during rave parties or other recreational events. A growing body of evidence suggests that strong environmental stressors might cause neuronal dysfunction on their own in addition to their synergistic action with illicit drugs. Mice were exposed to a combination of physical and sensory stressors that are reminiscent of those encountered in a rave party. However, this is not a model of rave because it lacks the rewarding properties of rave. A 14-h exposure to environmental stressors caused an impairment of hippocampal long-term potentiation (LTP) and spatial memory, and an enhanced phosphorylation of tau protein in the CA1 and CA3 regions. These effects were transient and critically depended on the activation of 5-HT2C serotonin receptors, which are highly expressed in the CA1 region. Acute systemic injection of the selective 5-HT2C antagonist, RS-102,221 (2 mg/kg, i.p., 2 min prior the onset of stress), prevented tau hyperphosphorylation and also corrected the defects in hippocampal LTP and spatial memory. These findings suggest that passive exposure to a combination of physical and sensory stressors causes a reversible hippocampal dysfunction, which might compromise mechanisms of synaptic plasticity and spatial memory for a few days. Drugs that block 5-HT2C receptors might protect the hippocampus against the detrimental effect of environmental stressors.

  14. Complex proteinopathy with accumulations of prion protein, hyperphosphorylated tau, α-synuclein and ubiquitin in experimental bovine spongiform encephalopathy of monkeys

    PubMed Central

    Cervenak, Juraj; Bu, Ming; Miller, Lindsay; Asher, David M.

    2014-01-01

    Proteins aggregate in several slowly progressive neurodegenerative diseases called ‘proteinopathies’. Studies with cell cultures and transgenic mice overexpressing mutated proteins suggested that aggregates of one protein induced misfolding and aggregation of other proteins as well – a possible common mechanism for some neurodegenerative diseases. However, most proteinopathies are ‘sporadic’, without gene mutation or overexpression. Thus, proteinopathies in WT animals genetically close to humans might be informative. Squirrel monkeys infected with the classical bovine spongiform encephalopathy agent developed an encephalopathy resembling variant Creutzfeldt–Jakob disease with accumulations not only of abnormal prion protein (PrPTSE), but also three other proteins: hyperphosphorylated tau (p-tau), α-synuclein and ubiquitin; β-amyloid protein (Aβ) did not accumulate. Severity of brain lesions correlated with spongiform degeneration. No amyloid was detected. These results suggested that PrPTSE enhanced formation of p-tau and aggregation of α-synuclein and ubiquitin, but not Aβ, providing a new experimental model for neurodegenerative diseases associated with complex proteinopathies. PMID:24769839

  15. Complex proteinopathy with accumulations of prion protein, hyperphosphorylated tau, α-synuclein and ubiquitin in experimental bovine spongiform encephalopathy of monkeys.

    PubMed

    Piccardo, Pedro; Cervenak, Juraj; Bu, Ming; Miller, Lindsay; Asher, David M

    2014-07-01

    Proteins aggregate in several slowly progressive neurodegenerative diseases called 'proteinopathies'. Studies with cell cultures and transgenic mice overexpressing mutated proteins suggested that aggregates of one protein induced misfolding and aggregation of other proteins as well - a possible common mechanism for some neurodegenerative diseases. However, most proteinopathies are 'sporadic', without gene mutation or overexpression. Thus, proteinopathies in WT animals genetically close to humans might be informative. Squirrel monkeys infected with the classical bovine spongiform encephalopathy agent developed an encephalopathy resembling variant Creutzfeldt-Jakob disease with accumulations not only of abnormal prion protein (PrP(TSE)), but also three other proteins: hyperphosphorylated tau (p-tau), α-synuclein and ubiquitin; β-amyloid protein (Aβ) did not accumulate. Severity of brain lesions correlated with spongiform degeneration. No amyloid was detected. These results suggested that PrP(TSE) enhanced formation of p-tau and aggregation of α-synuclein and ubiquitin, but not Aβ, providing a new experimental model for neurodegenerative diseases associated with complex proteinopathies.

  16. Traditional Chinese Medicine Huannao Yicong Decoction Extract Decreases Tau Hyperphosphorylation in the Brain of Alzheimer's Disease Model Rats Induced by Aβ1–42

    PubMed Central

    Jia, Xingxing; Liu, Jiangang

    2016-01-01

    Objective. Huannao Yicong Decoction (HYD, 还脑益聪方) has been shown to improve the learning and memory capabilities of Alzheimer's disease (AD) subjects. However, the underlying mechanism remains to be determined. Methods. Sixty Sprague-Dawley rats were divided equally and randomly into five different groups including control, positive control, and HYD granules of low dose, medium dose, and high dose by daily gavage. The sham-treated rats were also given the same volume of sterile water by gavage. Twelve SD rats were treated with the same amount of physiological saline. Twelve weeks later, learning and memory capabilities, Aβ content of the right brain and the expression of glycogen synthase kinase-3β (GSK-3β), total tau protein kinase (TTBK1), and cyclin-dependent kinase-5 (CDK-5) were tested. Results. Our results showed that high dose HYD treatment significantly improved the learning and memory capability of the AD rats and decreased the expression of TTBK1, GSK-3β, and CDK-5 in the hippocampal CA1 region. Conclusions. HYD treatment for 12 weeks significantly improved spatial learning and memory and effectively inhibited Aβ deposition, likely via reducing tau protein kinase expression and thus tau hyperphosphorylation and inflammatory injury. Taken together, these results suggest that HYD could be an effective treatment for AD. PMID:28018474

  17. Recognizing detachment-mode seafloor spreading in the deep geological past.

    PubMed

    Maffione, Marco; Morris, Antony; Anderson, Mark W

    2013-01-01

    Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct "detachment-mode" of seafloor spreading compared to classical magmatic accretion. Here we demonstrate a paleomagnetic methodology that allows unequivocal recognition of detachment-mode seafloor spreading in ancient ophiolites and apply this to a potential Jurassic detachment fault system in the Mirdita ophiolite (Albania). We show that footwall and hanging wall blocks either side of an inferred detachment have significantly different magnetizations that can only be explained by relative rotation during seafloor spreading. The style of rotation is shown to be identical to rolling hinge footwall rotation documented recently in OCCs in the Atlantic, confirming that detachment-mode spreading operated at least as far back as the Jurassic.

  18. Recognizing detachment-mode seafloor spreading in the deep geological past

    PubMed Central

    Maffione, Marco; Morris, Antony; Anderson, Mark W.

    2013-01-01

    Large-offset oceanic detachment faults are a characteristic of slow- and ultraslow-spreading ridges, leading to the formation of oceanic core complexes (OCCs) that expose upper mantle and lower crustal rocks on the seafloor. The lithospheric extension accommodated by these structures is now recognized as a fundamentally distinct “detachment-mode” of seafloor spreading compared to classical magmatic accretion. Here we demonstrate a paleomagnetic methodology that allows unequivocal recognition of detachment-mode seafloor spreading in ancient ophiolites and apply this to a potential Jurassic detachment fault system in the Mirdita ophiolite (Albania). We show that footwall and hanging wall blocks either side of an inferred detachment have significantly different magnetizations that can only be explained by relative rotation during seafloor spreading. The style of rotation is shown to be identical to rolling hinge footwall rotation documented recently in OCCs in the Atlantic, confirming that detachment-mode spreading operated at least as far back as the Jurassic. PMID:23903780

  19. Electron detachment from negative ions in a short laser pulse

    SciTech Connect

    Shearer, S. F. C.; Smyth, M. C.; Gribakin, G. F.

    2011-09-15

    We present an efficient and accurate method to study electron detachment from negative ions by a few-cycle linearly polarized laser pulse. The adiabatic saddle-point method of Gribakin and Kuchiev [Phys. Rev. A 55, 3760 (1997)] is adapted to calculate the transition amplitude for a short laser pulse. Its application to a pulse with N optical cycles produces 2(N+1) saddle points in complex time, which form a characteristic 'smile.' Numerical calculations are performed for H{sup -} in a 5-cycle pulse with frequency 0.0043 a.u. and intensities of 10{sup 10}, 5x10{sup 10}, and 10{sup 11} W/cm{sup 2}, and for various carrier-envelope phases. We determine the spectrum of the photoelectrons as a function of both energy and emission angle, as well as the angle-integrated energy spectra and total detachment probabilities. Our calculations show that the dominant contribution to the transition amplitude is given by 5-6 central saddle points, which correspond to the strongest part of the pulse. We examine the dependence of the photoelectron angular distributions on the carrier-envelope phase and show that measuring such distributions can provide a way of determining this phase.

  20. [Ocular blood flow and characteristics of retinal detachment].

    PubMed

    Roldán Pallarés, M; Ossama, I A; Contreras, E; Hernández, J; Ganado, T; Bravo, C

    2001-06-01

    To determine if ocular blood flow (OBF) changes in retinal detachment (RD) are related with its characteristics (extension, macular involvement, PVR or duration). 60 patients with unilateral rhegmatogenous RD and 20 patients were selected. Color Doppler Ultrasound was used to measure OBF velocities in the ophthalmic artery (OA), central retinal artery (CRA) and vein (CRV) and posterior ciliary arteries (PCA) of both eyes of each patient. The IOP and RD characteristics were considered. In each case the paired Student's T test (OBF) and Wilcoxon test (IOP) were used for the statistical analysis (p<5%). Peak systolic (PS) and end diastolic (ED) velocities of OA, PS of CRA and PS and ED of PCA were decreased in the RD eyes compared to the normal ones (p<0.05). The PS and ED rates of OA and PS of CRA were also decreased (p<0.05) in the other eyes compared to the normal ones. Both the decrease in velocity and in the IOP were related with 2 or more quadrants of RD (p<0.05), macula detachment (p<0.05), PVR >/=C(2) (p<0.05) and duration of >/=15 days (p<0.05). RD correlates with decreased ocular blood flow velocities and IOP in both the RD as well as in the other eye. The worse the characteristics of the RD, the lower the velocities and the IOP

  1. Forced Detachment of the CD2-CD58 Complex

    PubMed Central

    Bayas, M. V.; Schulten, K.; Leckband, D.

    2003-01-01

    The force-induced detachment of the adhesion protein complex CD2-CD58 was studied by steered molecular dynamics simulations. The forced detachment of CD2 and CD58 shows that the system can respond to an external force by two mechanisms, which depend on the loading rate. At the rapid loading rates of 70 and 35 pN/ps (pulling speeds of 1 and 0.5 Å/ps) the two proteins unfold before they separate, whereas at slower loading rates of 7 and 3.5 pN/ps (pulling speeds of 0.1 and 0.05 Å/ps), the proteins separate before the domains can unfold. When subjected to a constant force of 400 pN, the two proteins separated without significant structural distortion. These findings suggest that protein unfolding is not coupled to the adhesive function of CD2 and CD58. The simulations further confirm that salt bridges primarily determine the tensile strength of the protein-to-protein bond, and that the order of salt bridge rupture depends mainly on the position of the bond, relative to the line of action of the applied force. Salt bridges close to this line break first. The importance of each of the salt bridges for adhesion, determined from the simulations, correlates closely with their role in cell-to-cell adhesion and equilibrium binding determined by site-directed mutagenesis experiments. PMID:12668431

  2. Searching for heavy photons at Jefferson Lab using detached vertices

    NASA Astrophysics Data System (ADS)

    Weinstein, Lawrence; Szumila-Vance, Holly; HPS Collaboration Collaboration

    2017-01-01

    The Heavy Photon Search (HPS) experiment in Jefferson Lab Hall B will look for a new U(1) vector boson (called a ``heavy photon'', ``dark photon'', or A') in the mass range from 20 to 600 MeV/c2. This A' could potentially couple to the ordinary photon through kinetic mixing, which would create a coupling to electric charge of α' / α =ɛ2 . If so, then the A' can be produced through electron interactions with a heavy target through a process analogous to bremsstrahlung. The A' could then decay to e+e- . If the coupling ɛ is large, we can directly detect a peak in the e+e- mass spectrum above the dominant QED background. If ɛ is small, then we can look for e+e- events with a detached vertex resulting from A' decays downstream of the production target. In 2015 and 2016 we measured a few beam days each of 1.1 and 2.2 GeV electron scattering from tungsten using a large acceptance forward spectrometer consisting of a silicon vertex tracker located inside a dipole magnet and a lead tungstate electromagnetic calorimeter for triggering. This talk will present the detached vertex A' search, including preliminary results at 1.1 GeV if available.

  3. Aerosols optical properties in Titan's Detached Haze Layer

    NASA Astrophysics Data System (ADS)

    Seignovert, Benoit; Rannou, Pascal; Lavvas, Panayotis; West, Robert

    2016-10-01

    Titan's Detached Haze Layer (DHL) was first observed in 1983 by Rages and Pollack during the Voyager 2 is a consistent spherical haze feature surrounding Titan's upper atmosphere and detached from the main haze. Since 2005, the Imaging Science Subsystem (ISS) instrument on board the Cassini mission performs a continuous survey of the Titan's atmosphere and confirmed its persistence at 500 km up to the equinox (2009) before its drop and disappearance in 2012 (West et al. 2011). Previous analyses showed, that this layer corresponds to the transition area between small spherical aerosols and large fractal aggregates and play a key role in the aerosols formation in Titan's atmosphere (Rannou et al. 2000, Lavvas et al. 2009, Cours et al. 2011).In this talk we will present the UV photometric analyses based on radiative transfer inversion to retrieve aerosols particles properties in the DHL (bulk and monomer radius and local density) performed on ISS observations taken from 2005 to 2007.References:- Rages and Pollach, Icarus 55 (1983)- West, et al., Icarus 38 (2011)- Rannou, et al., Icarus 147 (2000)- Lavvas, et al., Icarus 201 (2009)- Cours, et al., ApJ Lett. 741 (2015)

  4. Vitreous Microparticle Shedding in Retinal Detachment: A Prospective Comparative Study.

    PubMed

    Tumahai, Perle; Saas, Philippe; Ricouard, Fanny; Biichlé, Sabéha; Puyraveau, Marc; Laheurte, Caroline; Delbosc, Bernard; Saleh, Maher

    2016-01-01

    Microparticles (MPs) are membrane-derived vesicles measuring less than 1 μm in diameter. They are shed from nearly every activated or preapoptotic cell and may exhibit biologic activities in inflammation or apoptosis settings. The main purpose of this study was to determine whether MP shedding was higher in the vitreous of patients with retinal detachment (RD). This was a prospective, comparative study. Levels of vitreous MPs (including phosphatidylserine [PS]-expressing MPs, photoreceptor cell-derived MPs, and photoreceptor cell-derived MPs expressing PS) and soluble proinflammatory factors (i.e., monocyte chemoattractant protein-1, intercellular adhesion molecule-1, and IL-6) were analyzed by flow cytometry. Samples were obtained from 49 eyes undergoing RD surgery and 41 control eyes. Vitreous levels of all the MPs studied were significantly increased in the RD group. Vitreous MP levels were correlated with levels of at least one proinflammatory factor depending on MP subsets. Concerning clinical parameters, vitreous PS-expressing MP and PS-expressing photoreceptor cell-derived MP levels were higher depending on the duration of RD at surgery, the detached retina surface, and the macula status and were found more sensitive than proinflammatory factors only for the duration of RD at surgery. Vitreous concentrations of MPs (mainly derived from photoreceptor cells) are higher after rhegmatogenous RD and found to be correlated with soluble proinflammatory factors.

  5. Electron attachment and detachment: Electron affinities of isomers of trifluoromethylbenzonitrile

    NASA Astrophysics Data System (ADS)

    Miller, Thomas M.; Viggiano, A. A.; Friedman, Jeffrey F.; Van Doren, Jane M.

    2004-11-01

    Rate constants for electron attachment to the three isomers of trifluoromethylbenzonitrile [(CF3)(CN)C6H4, or TFMBN] were measured over the temperature range of 303-463 K in a 133-Pa He buffer gas, using a flowing-afterglow Langmuir-probe apparatus. At 303 K, the measured attachment rate constants are 9.0×10-8 (o-TFMBN), 5.5×10-8 (m-TFMBN), and 8.9×10-8 cm3 s-1 (p-TFMBN), estimated accurate to ±25%. The attachment process formed only the parent anion in all three cases. Thermal electron detachment was observed for all three anion isomers, and rate constants for this reverse process were also measured. From the attachment and detachment results, the electron affinities of the three isomers of TFMBN were determined to be 0.70(o-TFMBN), 0.67(m-TFMBN), and 0.83 eV (p-TFMBN), all ±0.05 eV. G3(MP2) [Gaussian-3 calculations with reduced Møller-Plesset orders (MP2)] calculations were carried out for the neutrals and anions. Electron affinities derived from these calculations are in good agreement with the experimental values.

  6. Electron attachment and detachment: electron affinities of isomers of trifluoromethylbenzonitrile.

    PubMed

    Miller, Thomas M; Viggiano, A A; Friedman, Jeffrey F; Van Doren, Jane M

    2004-11-22

    Rate constants for electron attachment to the three isomers of trifluoromethylbenzonitrile [(CF(3))(CN)C(6)H(4), or TFMBN] were measured over the temperature range of 303-463 K in a 133-Pa He buffer gas, using a flowing-afterglow Langmuir-probe apparatus. At 303 K, the measured attachment rate constants are 9.0 x 10(-8) (o-TFMBN), 5.5 x 10(-8) (m-TFMBN), and 8.9 x 10(-8) cm(3) s(-1) (p-TFMBN), estimated accurate to +/-25%. The attachment process formed only the parent anion in all three cases. Thermal electron detachment was observed for all three anion isomers, and rate constants for this reverse process were also measured. From the attachment and detachment results, the electron affinities of the three isomers of TFMBN were determined to be 0.70(o-TFMBN), 0.67(m-TFMBN), and 0.83 eV (p-TFMBN), all +/-0.05 eV. G3(MP2) [Gaussian-3 calculations with reduced Møller-Plesset orders (MP2)] calculations were carried out for the neutrals and anions. Electron affinities derived from these calculations are in good agreement with the experimental values.

  7. Macula-Sparing Rhegmatogenous Retinal Detachment: Is Emergent Surgery Necessary?

    PubMed Central

    Mahmoudi, Sasan; Almony, Arghavan

    2016-01-01

    The status of the macula is a significant factor in determining final visual outcomes in rhegmatogenous retinal detachment (RRD) and should be considered in the timing of surgical repair. Several studies have shown that macula-involving RRDs attain similar visual and anatomic outcomes when surgery is performed within seven days as compared to emergent surgery (within 24 hours). In contrast, surgery prior to macular detachment in macula-sparing RRDs generally yields the best visual outcomes. In the case of macula-sparing RRDs, it is not clear how long the macula may remain attached, therefore, standard practice dictates emergent surgery. Timing of presentation, examination findings, case complexity, co-existing medical conditions, surgeon expertise, and timing and quality of access to operating facilities and staff, however, should all be considered in determining whether a macula-sparing RRD requires immediate intervention or if equivalent visual and possibly better overall outcomes can be achieved with scheduled surgery within an appropriate time frame. PMID:27195093

  8. Slab detachment modelling: geodynamic regimes, topographic response, and rheological mechanisms

    NASA Astrophysics Data System (ADS)

    Duretz, Thibault; Gerya, Taras

    2010-05-01

    A set of numerical experiments were carried out to study the effect of slab breakoff on a subduction-collision system. The numerical code I2VIS (Gerya & Yuen, 2003) used for this purpose allows activation of plasticity, viscous creep and Peierls creep. A two-dimensional systematic study was performed by varying the oceanic slab age and initial plate convergence rate. In this parameter space, four different end-members were observed where breakoff depth can range from 40 to 400 km. Different combinations of rheological mechanisms lead to different breakoff modes. Activation of Peierls mechanism generally allows slabs to break faster and shallower. Each breakoff end-member has its own topographic signal evolution and always display a sharp breakoff signal. Averaged post-breakoff uplift rates ranges between 0,8 km/My for shallow detachment and 0,2 km/My for deep detachment in foreland and hinterland basins. Initiation of continental crust subduction was observed when using an oceanic lithosphere older than 30 My. Different exhumation processes such as slab retreat and eduction were observed. Large post-breakoff rebound associated with plate de- coupling occurs if the subducted oceanic slab is old enough. REFERENCES Gerya, T. V. & Yuen, D. A. 2003: Charaterictics-based marker method with conservative finite-difference schemes for modeling geological flows with strongly variable transport properties. Physics of the Earth an Planetary Interiors 140 (4), 293-318.

  9. Modeling of Plasma Detachment from a Magnetic Nozzle

    NASA Astrophysics Data System (ADS)

    Glesner, Colin; Srinivasan, Bhuvana

    2015-11-01

    The detachment of plasma from a magnetic nozzle is examined using numerical simulations based on the discontinuous galerkin method. Plasma detachment is of interest for its role in the development of plasma based space propulsion systems. The simulation parameters used, modeled after the computational and experimental work of Winglee et al. result in β ~ 0 . 01 , and Rem ~ 0 . 3 . In this low- β regime perturbation of the initially imposed magnetic field is expected to be small. To more effectively study these perturbations, the ideal magnetohydrodynamic equations are modified by linearizing the magnetic field. The perturbative component is then evolved in the simulation rather than the total magnetic field, allowing for a clearer resolution of changes in the magnetic field produced by the plasma. Because of the intermediate range of magnetic Reynolds number present in this plasma configuration, the effect of introducing resistivity in the simulation is also examined. Further work will investigate the effect of varying the configuration of the magnetic field. Supported by a grant from the Virginia Space Grant Consortium.

  10. Bridgman Growth of Detached GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Kaiser, N.; Cobb, S. D.; Vujisic, L.; Motakef, S.; Szofran, F. R.

    2002-01-01

    Ge(1-x)Si(x) (0 less than x less than 0.12) has been grown by the vertical Bridgman technique using adjustments in the applied temperature profile to control the pressure difference between the bottom and top of the melt. Using this technique. a pressure difference is created by decreasing the temperature in the gas volume above the melt while the sample is molten but prior to growth. A maximum pressure difference approximately equal to the hydrostatic pressure of the molten sample can thus be obtained. Several GeSi crystals were grown in pyrolitic boron nitride ampoules. When a pressure difference was applied, samples were reproducibly grown mostly detached. For comparison, samples were also grown in a configuration in which gas could flow freely between the gap below the melt and the volume above the melt and no pressure difference could be established. These samples were initially attached. Existence of detachment was determined both by measuring the surface roughness of the samples with a profilometer and by observations of the sample surfaces with optical and electron microscopy.

  11. X-ray Characterization of Detached-Grown Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Raghothamachar, B.; Dudley, M.; Szoke, J.; Cobb, S. D.; Szofran, F. R.

    2005-01-01

    Germanium (111)-oriented crystals have been grown by the vertical Bridgman technique, in both detached and attached configurations. Microstructural characterization of these crystals has been performed using synchrotron white beam x-ray topography (SWBXT) and double axis x-ray diffraction. Dislocation densities were measured from x-ray topographs obtained using the reflection geometry. For detached-grown crystals, the dislocation density is 4-6 x 10(exp 4) per square centimeter in the seed region, and decreases in the direction of growth to less than 10(exp 3) per square centimeter, and in some crystals reaches less than 10(exp 2) per square centimeter. For crystals grown in the attached configuration, dislocation densities were on the order of 10(exp 4) per square centimeter in the middle of the crystals, increasing to greater than 10(exp 5) per square centimeter near the edge. The measured dislocation densities are in excellent agreement with etch pit density results. The rocking curve linewidths were relatively insensitive to the dislocation densities. However, broadening and splitting of the rocking curves were observed in the vicinity of subgrain boundaries identified by x-ray topography in some of the attached-grown crystals.

  12. Bridgman Growth of Detached GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Volz, M. P.; Schweizer, M.; Kaiser, N.; Cobb, S. D.; Vujisic, L.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Ge(1-x)Si(x)(0 less than x less than 0.12) has been grown by the vertical Bridgman technique using adjustments in the applied temperature profile to control the pressure difference between the bottom and top of the melt. Using this technique, a pressure difference is created by decreasing the temperature in the gas volume above the melt while the sample is molten but prior to growth. A maximum pressure difference approximately equal to the hydrostatic pressure of the molten sample can thus be obtained. Several GeSi crystals were grown in pyrolitic boron nitride ampoules. When a pressure difference was applied, samples were reproducibly grown mostly detached. For comparison, samples were also grown in a configuration in which gas could flow freely between the gap below the melt and the volume above the melt and no pressure difference could be established. These samples were initially attached. Existence of detachment was determined both by measuring the surface roughness of the samples with a profilometer and by observations of the sample surfaces with optical and electron microscopy.

  13. Sector mapping method for 3D detached retina visualization.

    PubMed

    Zhai, Yi-Ran; Zhao, Yong; Zhong, Jie; Li, Ke; Lu, Cui-Xin; Zhang, Bing

    2016-10-01

    A new sphere-mapping algorithm called sector mapping is introduced to map sector images to the sphere of an eyeball. The proposed sector-mapping algorithm is evaluated and compared with the plane-mapping algorithm adopted in previous work. A simulation that maps an image of concentric circles to the sphere of the eyeball and an analysis of the difference in distance between neighboring points in a plane and sector were used to compare the two mapping algorithms. A three-dimensional model of a whole retina with clear retinal detachment was generated using the Visualization Toolkit software. A comparison of the mapping results shows that the central part of the retina near the optic disc is stretched and its edges are compressed when the plane-mapping algorithm is used. A better mapping result is obtained by the sector-mapping algorithm than by the plane-mapping algorithm in both the simulation results and real clinical retinal detachment three-dimensional reconstruction.

  14. Limestone weathering rates accelerated by micron-scale grain detachment

    NASA Astrophysics Data System (ADS)

    Emmanuel, S.; Levenson, Y.

    2014-12-01

    The weathering rates of carbonate rocks is often thought to be controlled by chemical dissolution, although some studies have suggested that mechanical erosion could also play an important role. Quantifying the rates of the different processes has proved challenging due to the high degree of variability encountered in both field and lab settings. To determine the rates and mechanisms controlling long-term limestone weathering, we analyse a lidar scan of the Western Wall, a Roman period edifice located in Jerusalem. Weathering rates in fine-grained micritic limestone blocks are up to 2 orders of magnitude higher than the average rates estimated for coarse-grained limestone blocks at the same site. In addition, in experiments that use atomic force microscopy to image dissolving micritic limestone, we show that these higher reaction rates could be due to rapid dissolution along micron-scale grain boundaries, followed by mechanical detachment of tiny particles from the surface. Our analysis indicates that micron-scale grain detachment, rather than pure chemical dissolution, could be the dominant erosional mode for fine-grained rocks in many carbonate terrains.

  15. Plasma Detachment Studies in the VASIMR Magnetic Nozzle

    NASA Astrophysics Data System (ADS)

    Tarditi, Alfonso G.; Shebalin, John

    2004-11-01

    Two important issues related to the VASIMR (Variable Specific Impulse Magnetoplasma Rocket, [1]) experiment are the plasma detachment and the collimation of the plume in the magnetic nozzle. These issues are being investigated both through theory/simulation studies and now also experimentally. A 3D, nonlinear MHD/2-fluid model of the magnetic nozzle has been implemented with the NIMROD code. The model has been run both with the actual VASIMR geometry and for an ideal De Laval nozzle configuration. The simulations indicate a distortion of the external field due to the plasma exhaust flow (carrying an azimuthal diamagnetic current) that may to lead to plasma detachment through the formation of magnetic islands. This is also being investigated experimentally. A Hall-effect, one-axis, gaussmeter has shown the local low-frequency magnetic field fluctuations during a plasma pulse. A 2D array of 3-axis "B-dot" probes is being developed for a fast mapping of the field perturbations in the nozzle (on the order of the Alfven time). Finally, a Rogowski coil probe is being designed to measure the azimuthal current profile in the exhaust plasma. [1] F. R. Chang-Diaz et al, Scientific American, p. 90, Nov. 2000

  16. Current understanding of divertor detachment: experiments and modelling

    SciTech Connect

    Wischmeier, W; Groth, M; Kallenbach, A; Chankin, A; Coster, D; Dux, R; Herrmann, A; Muller, H; Pugno, R; Reiter, D; Scarabosio, A; Watkins, J; Team, T D; Team, A U

    2008-05-23

    A qualitative as well as quantitative evaluation of experimentally observed plasma parameters in the detached regime proves to be difficult for several tokamaks. A series of ohmic discharges have been performed in ASDEX Upgrade and DIII-D at similar as possible plasma parameters and at different line averaged densities, {bar n}{sub e}. The experimental data represent a set of well diagnosed discharges against which numerical simulations are compared. For the numerical modeling the fluid-code B2.5 coupled to the Monte Carlo neutrals transport code EIRENE is used. Only the combined enhancement of effects, such as geometry, drift terms, neutral conductance, increased radial transport and divertor target composition, explains a significant fraction of the experimentally observed asymmetries of the ion fluxes as a function of {bar n}{sub e} to the inner and outer target plates in ASDEX Upgrade. The relative importance of the mechanisms leading to detachment are different in DIII-D and ASDEX Upgrade.

  17. Predictive Computer Models for Biofilm Detachment Properties in Pseudomonas aeruginosa

    PubMed Central

    Cogan, Nick G.; Harro, Janette M.; Stoodley, Paul

    2016-01-01

    ABSTRACT Microbial biofilm communities are protected against environmental extremes or clearance by antimicrobial agents or the host immune response. They also serve as a site from which microbial populations search for new niches by dispersion via single planktonic cells or by detachment by protected biofilm aggregates that, until recently, were thought to become single cells ready for attachment. Mathematically modeling these events has provided investigators with testable hypotheses for further study. Such was the case in the recent article by Kragh et al. (K. N. Kragh, J. B. Hutchison, G. Melaugh, C. Rodesney, A. E. Roberts, Y. Irie, P. Ø. Jensen, S. P. Diggle, R. J. Allen, V. Gordon, and T. Bjarnsholt, mBio 7:e00237-16, 2016, http://dx.doi.org/10.1128/mBio.00237-16), in which investigators were able to identify the differential competitive advantage of biofilm aggregates to directly attach to surfaces compared to the single-celled planktonic populations. Therefore, as we delve deeper into the properties of the biofilm mode of growth, not only do we need to understand the complexity of biofilms, but we must also account for the properties of the dispersed and detached populations and their effect on reseeding. PMID:27302761

  18. Electric Field Effect on Bubble Detachment in Variable Gravity Environment

    NASA Technical Reports Server (NTRS)

    Iacona, Estelle; Herman, Cila; Chang, Shinan

    2003-01-01

    The subject of the present study, the process of bubble detachment from an orifice in a plane surface, shows some resemblance to bubble departure in boiling. Because of the high heat transfer coefficients associated with phase change processes, boiling is utilized in many industrial operations and is an attractive solution to cooling problems in aerospace engineering. In terrestrial conditions, buoyancy is responsible for bubble removal from the surface. In space, the gravity level being orders of magnitude smaller than on earth, bubbles formed during boiling remain attached at the surface. As a result, the amount of heat removed from the heated surface can decrease considerably. The use of electric fields is proposed to control bubble behavior and help bubble removal from the surface on which they form. The objective of the study is to investigate the behavior of individual air bubbles injected through an orifice into an electrically insulating liquid under the influence of a static electric field. Bubble cycle life were visualized in terrestrial conditions and for several reduced gravity levels. Bubble volume, dimensions and contact angle at detachment were measured and analyzed for different parameters as gravity level and electric field magnitude. Situations were considered with uniform or non-uni form electric field. Results show that these parameters significantly affect bubble behavior, shape, volume and dimensions.

  19. Attainment of a stable, fully detached plasma state in innovative divertor configurations

    NASA Astrophysics Data System (ADS)

    Umansky, Maxim

    2016-10-01

    The heat load on plasma facing components is a critical engineering constraint for future tokamaks, which has stimulated the community to consider innovative magnetic divertor geometries for future high power devices. Present-day advanced divertor scenarios generally rely on partially detached regimes, also planned for ITER; a fully detached state would usually lead to MARFE and degradation of core confinement. Modeling reveals that novel magnetic geometries can have a major impact on plasma detachment and power handling. Using the UEDGE tokamak edge transport model for configurations with tightly baffled long divertor legs, extended radially, or vertically, we find stable, fully detached divertor operation. Including a secondary X-point in the outer leg volume extends the attainment of a stable detached state to the highest power. As the input power is reduced to a threshold value, the outer leg transitions to a fully detached state with the detachment front localized at the secondary X-point or in the leg volume; reducing the power further results in the detachment front steady-state location shifting upstream. As the power is reduced, the detachment front eventually moves to the primary X-point, which sets the lower power limit for the range of stable operation. Still, for a long-legged divertor, a fully detached, stable divertor regime is maintained over an order-of-magnitude variation in exhaust power. In contrast, a standard divertor has a much smaller detachment operational window. These results suggest that stable fully detached divertor operation can be realized in tokamaks with extended divertor legs.

  20. Delayed macular hole formation after demarcation laser photocoagulation for subclinical retinal detachment.

    PubMed

    Rusu, Irene M; Zizva, Jessica; Myung, Jane S; Wald, Kenneth

    2014-01-01

    The purpose of this paper is to report a series of macular holes that developed after demarcation laser photocoagulation for subclinical retinal detachments. This observational case series consists of three eyes from three patients seen between 2005 and 2012. Delayed idiopathic macular hole formation occurred following demarcation laser photocoagulation for subclinical retinal detachment. Demarcation laser photocoagulation of subclinical retinal detachments may predispose to macular hole formation.

  1. Serous Macular Detachment Secondary to Optic Pit: Surgical Treatment and Long Time Results

    PubMed Central

    Cevher, Selim; Sahinoglu-Keskek, Nedime; Unal, Fikret; Demirduzen, Selahaddin; Oksuz, Huseyin

    2016-01-01

    32-year-old Turkish male patient presented with an optic disk pit and serous macular detachment in the left eye. Spectral domain optical coherence tomography revealed serous macular detachment and retinoschisis. After vitrectomy the retina gradually flattened and vision was gradually improved. We aimed to report a case of serous macula detachment secondary to optic pit and long term result of surgical treatment. PMID:26881159

  2. Synkinematic skarns and fluid drainage along detachments: The West Cycladic Detachment System on Serifos Island (Cyclades, Greece) and its related mineralization

    NASA Astrophysics Data System (ADS)

    Ducoux, M.; Branquet, Y.; Jolivet, L.; Arbaret, L.; Grasemann, B.; Rabillard, A.; Gumiaux, C.; Drufin, S.

    2017-01-01

    Back-arc extension in the Aegean Sea has been accommodated by several large-scale detachments such as the West Cycladic Detachment System (WCDS) in the Oligocene and Miocene. The WCDS especially crops out on Serifos Island (Cyclades) with a synkinematic granodioritic intrusion. As skarns represent metasomatic reactions near the contact between intrusions and the host rocks, they sign the position of the main drains used by fluids. While the mineralogy of the Serifos skarns is well known, geometrical and kinematic relations between the detachments and ore bodies remains poorly studied. This study allows us to distinguish different types of skarn. High Temperature skarns correspond to (1) massive garnet endoskarns, (2) ribbon and ;bubble; garnet-pyroxene endoskarns, (3) garnet-pyroxene cracks exoskarns, whereas medium-temperature pyroxene ± ilvaite bearing skarn breccias within the Meghàlo Livadhi and Kàvos Kiklopas detachments belonging to the WCDS. Our observations show that skarn formation is associated with the activity of detachments and the syntectonic pluton emplacement. Endo and exoskarn deposits formed coeval with the ductile and brittle structures resulting from the activity of the WCDS, such as echelon veins, veins with antithetic shear and boudinaged veins wrapped within sheath folds, with a top-to-the SSW or SW shear senses compatible with the regional kinematics. Some skarn breccias formed within detachment planes far from the contact of the main granodioritic body, attesting for the intense flow of magmatic fluids along these discontinuities. These over-pressurized fluids play a major role in the mechanical behaviour of the detachments and strain localization. The two detachments acting as preferential crustal-scale drains, the pattern of magmatic fluid flows is not centred on the intrusion. In this context, iron-rich skarns and associated primary magnetite deposits have been remobilized during late brittle increments of motion along the detachments

  3. Diagnostic tools for studying divertor detachment: bolometry, spectroscopy, and thermography for surface heat-flux

    NASA Astrophysics Data System (ADS)

    Terry, J. L.; Reinke, M. L.

    2017-04-01

    Some of the key aspects of divertor detachment that are addressed by bolometry, impurity spectroscopy, hydrogen spectroscopy, and measurements of divertor target heat-flux are reviewed. Measurement requirements for these diagnostic areas are defined, and brief descriptions of the techniques used for these diagnostics are given. Examples from the literature of measurements using these tools applied to detachment are presented. Feedback control of detachment using some of these diagnostics as the ‘sensors’ is reviewed. Challenges and some future directions for these diagnostics in the context of studying divertor detachment are described.

  4. Adhesion mechanism of a gecko-inspired oblique structure with an adhesive tip for asymmetric detachment

    NASA Astrophysics Data System (ADS)

    Sekiguchi, Yu; Takahashi, Kunio; Sato, Chiaki

    2015-12-01

    An adhesion model of an oblique structure with an adhesive tip is proposed by considering a limiting stress for adhesion to describe the detachment mechanism of gecko foot hairs. When a force is applied to the root of the oblique structure, normal and shear stresses are generated at contact and the adhesive tip is detached from the surface when reaching the limiting stress. An adhesion criterion that considers both the normal and shear stresses is introduced, and the asymmetric detachment of the oblique structure is theoretically investigated. In addition, oblique beam array structures are manufactured, and an inclination effect of the structure on the asymmetric detachment is experimentally verified.

  5. Experimental retinal detachment causes widespread and multilayered degeneration in rabbit retina.

    PubMed

    Faude, F; Francke, M; Makarov, F; Schuck, J; Gärtner, U; Reichelt, W; Wiedemann, P; Wolburg, H; Reichenbach, A

    2001-05-01

    Retinal detachment remains one of the most frequent causes of visual impairment in humans, even after ophthalmoscopically successful retinal reattachment. This study was aimed at monitoring (ultra-) structural alterations of retinae of rabbits after experimental detachment. A surgical procedure was used to produce local retinal detachments in rabbit eyes similar to the typical lesions in human patients. At various periods after detachment, the detached retinal area as well as neighbouring attached regions were studied by light and electron microscopy. In addition to the well-known degeneration of photoreceptor cells in the detached retina, the following progressive alterations were observed, (i) in both the detached and the attached regions, an incomplete but severe loss of ganglion cell axons occurs; (ii) there is considerable ganglion cell death, particularly in the detached area; (iii) even in the attached retina distant from the detachment, small adherent groups of photoreceptor cells degenerate; (iv) these photoreceptor cells degenerate in an atypical sequence, with severely destructed somata and inner segments but well-maintained outer segments; and (v) the severe loss of retinal neurons is not accompanied by any significant loss of Müller (glial) cells. It is noteworthy that the described progressive (and probably irreparable) retinal destructions occur also in the attached retina, and may account for visual impairment in strikingly large areas of the visual field, even after retinal reattachment.

  6. Molecular-level mechanisms of nanoparticle detachment in laser-induced plasma shock waves

    SciTech Connect

    Zhou Dong; Cetinkaya, Cetin

    2006-04-24

    Detachment and detachment mechanisms of nanoparticles from flat surfaces subjected to shock waves are investigated by employing molecular gas dynamic simulations using the direct simulation Monte Carlo method and experimental transient pressure data. Two mechanisms for nanoparticle detachment based on rolling moment resistance of the adhesion bond and the elastic restitution effect are introduced. As a result of present simulations, it is computationally demonstrated that the pulsed laser-induced shock waves can generate sufficient rolling moments to detach sub-100-nm particles and initiate removal. The transient moment exerted on a 60 nm polystyrene latex particle on a silicon substrate is presented and discussed.

  7. Molecular-level mechanisms of nanoparticle detachment in laser-induced plasma shock waves

    NASA Astrophysics Data System (ADS)

    Zhou, Dong; Cetinkaya, Cetin

    2006-04-01

    Detachment and detachment mechanisms of nanoparticles from flat surfaces subjected to shock waves are investigated by employing molecular gas dynamic simulations using the direct simulation Monte Carlo method and experimental transient pressure data. Two mechanisms for nanoparticle detachment based on rolling moment resistance of the adhesion bond and the elastic restitution effect are introduced. As a result of present simulations, it is computationally demonstrated that the pulsed laser-induced shock waves can generate sufficient rolling moments to detach sub-100-nm particles and initiate removal. The transient moment exerted on a 60nm polystyrene latex particle on a silicon substrate is presented and discussed.

  8. Receptor-mediated cell attachment and detachment kinetics. II. Experimental model studies with the radial-flow detachment assay.

    PubMed Central

    Cozens-Roberts, C; Quinn, J A; Lauffenburger, D A

    1990-01-01

    Quantitative information regarding the kinetics of receptor-mediated cell adhesion to a ligand-coated surface are crucial for understanding the role of certain key parameters in many physiological and biotechnology-related processes. Here, we use the probabilistic attachment and detachment models developed in the preceding paper to interpret transient data from well-defined experiments. These data are obtained with a simple model cell system that consists of receptor-coated latex beads (prototype cells) and a Radial-Flow Detachment Assay (RFDA) using a ligand-coated glass disc. The receptors and ligands used in this work are complementary antibodies. The beads enable us to examine transient behavior with particles that possess fairly uniform properties that can be varied systematically, and the RFDA is designed for direct observation of adhesion to the ligand-coated glass surface over a range of shear stresses. Our experiments focus on the effects of surface shear stress, receptor density, and ligand density. These data provide a crucial test of the probabilistic framework. We show that these data can be explained with the probabilistic analyses, whereas they cannot be readily interpreted on the basis of a deterministic analysis. In addition, we examine transient data on cell adhesion reported from other assays, demonstrating the consistency of these data with the predictions of the probabilistic models. Images FIGURE 2 PMID:2174272

  9. Slip on serpentine detachments at magma-poor margins

    NASA Astrophysics Data System (ADS)

    Reston, Timothy; Lymer, Gael; Cresswell, Derren; Stevenson, Carl; Bull, Jonathan; Sawyer, Dale; Morgan, Julia; Galicia 3D working Group

    2017-04-01

    At magma-poor margins, the structures formed during rifting are not obscured by thick lavas, allowing detailed analysis of the tectonics of rifting and breakup. At most of these margins, the mantle beneath the thin crust has unusually low velocities, interpreted as a consequence of serpentinization following the embrittlement of the crust during rifting; models for the onset of serpentinization predict the thicknesses of crust that are observed at the landward limit of the serpentinized mantle. At a handful of margins the top of the serpentinized mantle appears to have acted as a detachment or decollement: faults that bound the overlying crustal blocks root on a bright reflection at the base of these blocks. Examples include the P reflection west of Ireland, the H reflection west of northern Portugal, and the S reflector west of Galicia. Corrugations observed on a 3D volume collected in 2013 above the S reflector strongly support its interpretation as a slip surface. A remaining question is whether slip on these "serpentine detachments" occurred at low-angle or not: for typical friction coefficients of 0.7, normal faults should lock-up and be replaced by steeper faults once they have rotated to perhaps 35°, an observation consistent with earthquake data. This angle can be reduced to 20-25° if the fault zone is composed of weak minerals such as serpentine. One possibility is that the detachment is actually composed of segments of faults that were active sequentially in a rolling hinge model. Beneath the centre of the Porcupine basin, the P reflection is sub-horizontal but its western continuation dips beneath the Porcupine bank at 20-25°, consistent with slip on serpentine-weakened rolling hinge system. West of Galicia, based on the geometrical relationships between late synrift wedges and their bounding faults which root on S, S has been interpreted to have slipped at angles below 20-25°. However, a 3D dataset collected over S in 2013 provides the opportunity

  10. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in Space

    NASA Technical Reports Server (NTRS)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    The safety issue has been raised with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. This investigation was undertaken to evaluate if molten metal could detach and come in contact with astronauts and burn through the fabric of the astronauts' Extravehicular Mobility Unit (EMU) during electron beam welding in space. Molten metal detachments from either the weld/cut substrate or weld wire could present harm to a astronaut if the detachment was to burn through the fabric of the EMU. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at Low Earth Orbit (LEO). The primary molten metal detachment concerns were those cases of molten metal separation from the metal surface due to metal cutting, weld pool splashing, entrainment and release of molten metal due to filler wire snap-out from the weld puddle, and molten metal accumulation and release from the end of the weld wire. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. The surface tension represents the force opposing the liquid metal drop from detaching whereas the weight of the liquid metal droplet represents a force that is tending to detach the molten metal drop. Theoretical calculations have indicated that only a small amount of energy is required to detach a liquid metal drop; however, much of the energy of an impact is absorbed in the sample or weld plate before it reaches the metal drop on the cut edge or surface. The tendency for detachment is directly proportional to the weld pool radius and metal density and inversely proportional to the surface

  11. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in Space

    NASA Technical Reports Server (NTRS)

    Fragomeni, James M.; Nunes, Arthur C., Jr.

    1998-01-01

    The safety issue has been raised with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. This investigation was undertaken to evaluate if molten metal could detach and come in contact with astronauts and burn through the fabric of the astronauts' Extravehicular Mobility Unit (EMU) during electron beam welding in space. Molten metal detachments from either the weld/cut substrate or weld wire could present harm to a astronaut if the detachment was to burn through the fabric of the EMU. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at Low Earth Orbit (LEO). The primary molten metal detachment concerns were those cases of molten metal separation from the metal surface due to metal cutting, weld pool splashing, entrainment and release of molten metal due to filler wire snap-out from the weld puddle, and molten metal accumulation and release from the end of the weld wire. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were developed for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. The surface tension represents the force opposing the liquid metal drop from detaching whereas the weight of the liquid metal droplet represents a force that is tending to detach the molten metal drop. Theoretical calculations have indicated that only a small amount of energy is required to detach a liquid metal drop; however, much of the energy of an impact is absorbed in the sample or weld plate before it reaches the metal drop on the cut edge or surface. The tendency for detachment is directly proportional to the weld pool radius and metal density and inversely proportional to the surface

  12. Characterization of Surface Features in Detached Grown GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Cobb, S. D.; Volz, M. P.; Schweizer, M.; Kaiser, N.; Carpenter, P. K.; Szofran, F. R.; Rose, M. Franklin (Technical Monitor)

    2001-01-01

    The growth of detached crystals by the Bridgman technique, in which the growing crystal is not in contact with the crucible wall, has been observed both on earth and in microgravity conditions. At present, the mechanisms contributing to the detachment are not completely understood and until recently detachment has not been reproducibly obtained. It is commonly understood that the main factors that promote the occurrence of detached growth include: high contact angle between the melt and the crucible material, high growth angle, and a pressure difference between the annular gap around the solid below the melt and the volume above the melt along the meniscus. These parameters were varied in Bridgman growth experiments to determine the conditions required to achieve detached growth terrestrially in Ge and GeSi alloys. These experiments are in preparation for experiments on the International Space Station (ISS). The detailed objectives of the flight experiments and a description of the growth methods employed are the subject of another presentation at this Congress. Detached crystals were achieved repeatedly in pyrolytic boron nitride ampoules when a pressure difference was employed. All crystals, except for those grown in fused silica ampoules, were easily removed from their containers; however, this fact alone is not sufficient to infer detached growth. Detachment was verified by comparing profilometer measurements of the radius of the samples with observations of the sample surfaces using optical and electron microscopy. The surfaces of the attached areas of the crystals had the same shape and surface texture as the interior crucible wall. Regions of detached growth contained many unique features and crystal facets could usually be observed. Several of these surface features have been correlated with mechanisms of detachment or free surface growth in general and others to processing events or conditions. These results will be compared with observations of surface

  13. Detached Eddy Simulation of Flap Side-Edge Flow

    NASA Technical Reports Server (NTRS)

    Balakrishnan, Shankar K.; Shariff, Karim R.

    2016-01-01

    Detached Eddy Simulation (DES) of flap side-edge flow was performed with a wing and half-span flap configuration used in previous experimental and numerical studies. The focus of the study is the unsteady flow features responsible for the production of far-field noise. The simulation was performed at a Reynolds number (based on the main wing chord) of 3.7 million. Reynolds Averaged Navier-Stokes (RANS) simulations were performed as a precursor to the DES. The results of these precursor simulations match previous experimental and RANS results closely. Although the present DES simulations have not reached statistical stationary yet, some unsteady features of the developing flap side-edge flowfield are presented. In the final paper it is expected that statistically stationary results will be presented including comparisons of surface pressure spectra with experimental data.

  14. Macular Hole Formation in Rhegmatogenous Retinal Detachment after Scleral Buckling

    PubMed Central

    Byon, Ik Soo; Kwon, Han Jo; Park, Gun Hyung; Park, Sung Who

    2014-01-01

    Purpose To describe early macular hole (MH) development in rhegmatogenous retinal detachment (RRD) after scleral buckling (SB) based on optical coherence tomography (OCT) findings. Methods The medical records and spectral domain OCT images of patients in whom MH developed after RRD repair were evaluated retrospectively. Results A postoperative MH was detected in five eyes that underwent SB during a 6-year period. All had fovea-off RRD without MH at the time of surgery. OCT showed partial loss of the inner retina with a preserved photoreceptor layer in early postoperative days. On average, 7 days (range,5 to 8 days) after surgery, outer retinal tissues disappeared, resulting in the full-thickness MH. Conclusions Serial OCT findings revealed that partial-thickness lamellar holes progressed to full-thickness MHs, which were formed by the degeneration of the outer retina in eyes with preceding loss of the glial cone in the fovea. PMID:25276077

  15. Status of Magnetic Nozzle and Plasma Detachment Experiment

    SciTech Connect

    Chavers, D. Gregory; Dobson, Chris; Jones, Jonathan; Lee, Michael; Martin, Adam; Gregory, Judith; Cecil, Jim; Bengtson, Roger D.; Breizman, Boris; Arefiev, Alexey; Chang-Diaz, Franklin; Squire, Jared; Glover, Tim; McCaskill, Greg; Cassibry, Jason; Li Zhongmin

    2006-01-20

    High power plasma propulsion can move large payloads for orbit transfer, lunar missions, and beyond with large savings in fuel consumption owing to the high specific impulse. At high power, lifetime of the thruster becomes an issue. Electrodeless devices with magnetically guided plasma offer the advantage of long life since magnetic fields confine the plasma radially and keep it from impacting the material surfaces. For decades, concerns have been raised about the plasma remaining attached to the magnetic field and returning to the vehicle along the closed magnetic field lines. Recent analysis suggests that this may not be an issue if the magnetic field is properly shaped in the nozzle region and the plasma has sufficient energy density to stretch the magnetic field downstream. An experiment is being performed to test the theory regarding the MHD detachment scenario. The status of that experiment will be discussed in this paper.

  16. Changes in spectral properties of detached birch leaves

    NASA Technical Reports Server (NTRS)

    Daughtry, C. S. T.; Biehl, L. L.

    1985-01-01

    A study conducted in order to determine the rate of changes in spectral properties of detached leaves and to evaluate the effectiveness of low temperature and cytokinins for delaying the changes, is examined. For five minutes, leaves from red birch are immersed in water or 0.001 M BAP, and then stored in plastic bags in the dark at either 5 or 25 C. Using a spectroradiometer and an integrating sphere, total directional-hemispherical reflectance and transmittance of the adaxial surface of the leaves are measured over the 400-1100 nm wavelength region. The results indicate that for leaves stored at 5 C for one week, the changes in the spectral properties are less than 5 percent of the initial values, whereas storage at 25 C promotes rapid senescence and large changes in the spectral properties. It is shown that low temperature is more effective than BAP in delaying senescence.

  17. Volcanic fluidization and the Heart Mountain detachment, Wyoming

    NASA Astrophysics Data System (ADS)

    Beutner, Edward C.; Craven, Amy E.

    1996-07-01

    The presence along the Heart Mountain detachment in Wyoming of microbreccia containing volcanic glass grains with primary shapes and accreted grains equivalent to accretionary and armored lapilli supports the concept that injection of volcanic gases along the fault produced fluidization. The probable source of the volcanic contribution was a fixed feeder pipe, now beneath the Crandall intrusive complex, which left a trail of intrusives akin to a hotspot trace in the moving allochthon. Volcanic gas carrying glass and fluidized microbreccia was injected in sill-like fashion along a bedding horizon near the base of the Ordovician Bighorn Dolomite, resulting in gravitative collapse and spreading, probably catastrophic, of the overlying carbonate and volcanic massif.

  18. Urothelial cell detachment and differentiation in urinary bladder.

    PubMed

    Jezernik, K; Romih, R; Veranic, P

    2000-01-01

    In developing and in repairing bladder, proliferation of the transitional urothelium is followed by cell detachment--desquamation or apoptosis. Proliferation results in formation of terminally differentiated superficial cells and this process may be followed by checking the cells on the presence of differentiation markers. The formation of an asymmetric unit membrane (AUM) structure (plaque) on the cell surface is in correlation with urothelial differentiation. Thus, the microstructure of the luminal surface of the urinary bladder provides a very convenient differentiation biomarker. The surface of immature cells showed a pattern of microvilli. The progress of differentiation was associated with microvili arranged in rows finally forming the characteristic pattern of ridges in terminally differentiated cells. These results demonstrate that the characteristic surface pattern and the AUM plaque formation in the apical plasma membrane of superficial urothelial cells are associated with specific morphology, and patterns and thus help detect differentiation level of cell.

  19. Perfluorocarbon liquids in the management of complicated retinal detachments.

    PubMed

    Comaratta, M R; Chang, S

    1991-06-01

    Low viscosity perfluorocarbon liquids have unique physical properties making them ideal for the temporary tamponade, mechanical fixation, and manipulation of the retina. These substances are optically clear, have a specific gravity greater than that of water, and have interfacial tension properties similar to those of silicone oil. The temporary mechanical fixation of the retina by perfluorocarbon liquids facilitates the removal of epiretinal membranes and release of tractional forces. Intraoperative flattening of the retina under perfluorocarbon liquid eliminates the need for a posterior retinotomy. Perfluorocarbon liquids are being used intraoperatively for hydrokinetic manipulation of the retina during vitrectomy for complicated retinal detachments secondary to proliferative vitreoretinopathy, giant retinal tears, and trauma. Additional indications for the intraoperative utilization of perfluorocarbon liquids in vitreous surgery are discussed.

  20. Changes in spectral properties of detached birch leaves

    NASA Technical Reports Server (NTRS)

    Daughtry, C. S. T.; Biehl, L. L.

    1985-01-01

    A study conducted in order to determine the rate of changes in spectral properties of detached leaves and to evaluate the effectiveness of low temperature and cytokinins for delaying the changes, is examined. For five minutes, leaves from red birch are immersed in water or 0.001 M BAP, and then stored in plastic bags in the dark at either 5 or 25 C. Using a spectroradiometer and an integrating sphere, total directional-hemispherical reflectance and transmittance of the adaxial surface of the leaves are measured over the 400-1100 nm wavelength region. The results indicate that for leaves stored at 5 C for one week, the changes in the spectral properties are less than 5 percent of the initial values, whereas storage at 25 C promotes rapid senescence and large changes in the spectral properties. It is shown that low temperature is more effective than BAP in delaying senescence.

  1. Detached Eddy Simulation of a Nose Landing-Gear Cavity

    NASA Astrophysics Data System (ADS)

    Langtry, R.; Spalart, P.

    Some aircraft have exhibited a noticeable vibration and aero-acoustic phenomenon inside the nose landing gear cavity. The goal of the present study was to determine whether unsteady CFD using either unsteady RANS or detached eddy simulation (DES) could predict the cavity oscillation that was measured in a Boeing wind tunnel test. In general the agreement between the experiment and CFD was good. The CFD predicted an aircraft scale cavity tone frequency of 17 Hz compared to the measured value of 15 Hz. As well, the CFD predicted sound pressure level of the tone was within 4 dB of the measurements. From the present results it would appear that CFD can be used as a tool to investigate and possibly mitigate nose gear cavity tone mechanisms on new aircraft designs.

  2. Retinoschisis and neurosensory detachment in advanced focal glaucoma.

    PubMed

    Arranz-Márquez, E; Jarrín Hernández, E; Pastor, A; García Gil de Bernabé, J

    2016-11-22

    A 71-year-old woman with normotensive primary open-angle glaucoma presented with an asymptomatic temporal peripapillary retinoschisis, associated with serous retinal detachment in the eye with the more advanced glaucoma. It was located at the inferior pole of the optic disc, in the proximity of a glaucomatous focal disc defect. Although congenital optic pits are strongly related with juxta-papillary retinoschisis, retinoschisis can also arise from acquired defects in the proximity of glaucomatous optic discs. As symptoms depend on the extent of the retinoschisis, the prevalence of this complication could be greater than that reported in glaucomatous eyes. Copyright © 2016 Sociedad Española de Oftalmología. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Secular period decreasing of 17 detached chromospherically active binaries

    NASA Astrophysics Data System (ADS)

    Luo, C. Q.; Luo, Y. P.; Zhang, X. B.; Deng, L. C.; Luo, Z. Q.; Yang, S. Z.

    2008-10-01

    The long-term orbital period changes of detached chromospheric active binaries were surveyed. 17 of such systems are found to be undergoing secular period decreasing with the rates (dP/dt) of -3.05 × 10-9 to -3.77 × 10-5 days per year. The longer the orbital period, the more rapidly the period decreases. Following Stepien (1995), the period decreasing rate due to the angular momentum loss (AML) caused by magnetic wind is computed for each system. A comparison shows that the observed dP/dt's are obviously higher than that of the theoretical predictions by 1-3 orders of magnitude. It suggests that the magnetic wind is not likely the determinant mechanism driving the AML in close binaries.

  4. Compatibility of detached divertor operation with robust edge pedestal performance

    NASA Astrophysics Data System (ADS)

    Leonard, A. W.; Makowski, M. A.; McLean, A. G.; Osborne, T. H.; Snyder, P. B.

    2015-08-01

    The compatibility of detached radiative divertor operation with a robust H-mode pedestal is examined in DIII-D. A density scan produced low temperature plasmas at the divertor target, Te ⩽ 2 eV, with high radiation leading to a factor of ⩾4 drop in peak divertor heat flux. The cold radiative plasma was confined to the divertor and did not extend across the separatrix in X-point region. A robust H-mode pedestal was maintained with a small degradation in pedestal pressure at the highest densities. The response of the pedestal pressure to increasing density is reproduced by the EPED pedestal model. However, agreement of the EPED model with experiment at high density requires an assumption of reduced diamagnetic stabilization of edge Peeling-Ballooning modes.

  5. Associative electron detachment - O(-) + H yields OH + e(-)

    NASA Astrophysics Data System (ADS)

    Acharya, P. K.; Kendall, R. A.; Simons, J.

    1985-10-01

    Diatomic associative electron detachment (AED) involves the ejection of an electron when a atomic anion and another atom collisionally associate to produce a neutral diatomic molecule in a vibration-rotation state labeled V-prime, J-prime. Electron ejection rate calculations are discussed, taking into account aspects of rate expressions, calculations of ingredients in rate expression, initial-condition weighting factors, and the vibration and rotation dependence of ejection rates. The results of ab initio theoretical simulations indicate that AED in O(-) + H is so slow (approximately 10,000 per s) that it is likely to be inaccessible to present experimental observation. Propensity for producing OH in high vibrational levels does occur but the propensity is not sharp.

  6. Descemet's membrane detachments post cataract surgery: a management paradigm

    PubMed Central

    Samarawickrama, Chameen; Beltz, Jacqueline; Chan, Elsie

    2016-01-01

    Descemet's membrane detachments (DMD) are relatively common after cataract surgery and most do not require any treatment. However, if large DMD are not treated appropriately, significant visual morbidity can ensue. We aim to develop a guideline for the management of DMD post cataract surgery based on a retrospective review of all cases encountered at the Royal Victorian Eye and Ear Hospital, Melbourne, Australia over a 4-year period from 2010 to 2014. We suggest conservative management if the visual axis is not involved; however, after 3mo surgical intervention may be warranted to prevent corneal sequelae. In cases where the visual axis is involved we suggest early intervention with air tamponade. The main risk factor for irreversible corneal oedema and subsequent endothelial transplant appears to be direct endothelial trauma rather than the DMD itself. PMID:28003989

  7. Surgical challenges and outcomes of rhegmatogenous retinal detachment in albinism

    PubMed Central

    Sinha, M K; Chhablani, J; Shah, B S; Narayanan, R; Jalali, S

    2016-01-01

    Purpose To report the outcomes and surgical difficulties during rhegmatogenous retinal detachment (RRD) repair in patients with albinism. Methods Retrospective analysis of 10 eyes of 9 patients with albinism that underwent RRD repair was performed. Collected data included demographic details, preoperative examination details, surgical procedure, surgical difficulties, anatomical, and visual outcomes. Outcome measures were retinal reattachment and visual acuity at the last follow-up. Results Mean preoperative best-corrected visual acuity (BCVA) was logMAR (Logarithm of the Minimum Angle of Resolution) 2.15 (range 0.9–3.0) with preoperative localization of causative break in six eyes. One eye had proliferative vitreoretinopathy grade C1 preoperatively. Four eyes underwent scleral buckling (SB) and six underwent 20G pars plana vitrectomy (PPV) with silicone oil injection. Intraoperative complication as iatrogenic retinal break occurred in four eyes. For retinopexy during vitrectomy, endolaser delivery was possible in three out of six eyes, whereas three eyes had cryopexy. The mean follow-up was 12 months in SB group (range 1–12; median 12 months) and 5.33 months (range 1–12; median 3 months) in PPV group. Among vitrectomized eye, two eyes had recurrence at 3 months with oil in situ. Rest of the eyes had attached retina at last follow-up. Mean BCVA at last follow-up was logMAR −1.46 (range 0.7–2.0) with mean improvement of −0.57 logMAR. Conclusions Identification of break, induction of posterior vitreous detachment, and endolaser delivery may be difficult during RRD repair in patients with albinism. The incidence of PVR appeared less in these eyes. Both SB and PPV were efficacious and appear to be good surgical techniques for use in this patient population. PMID:26611845

  8. Grip and detachment of locusts on inverted sandpaper substrates.

    PubMed

    Han, Longbao; Wang, Zhouyi; Ji, Aihong; Dai, Zhendong

    2011-12-01

    Locusts (Locusta migratoria manilensis) are characterized by their strong flying and grasping ability. Research on the grasping mechanism and behaviour of locusts on sloping substrates plays an important role in elucidating the mechanics of hexapod locomotion. Data on the maximum angles of slope at which locusts can grasp stably (critical angles of detachment) were obtained from high-speed video recordings at 215 fps. The grasping forces were collected by using two sensors, in situations where all left legs were standing on one and the right legs on the other sensor plate. These data were used to illustrate the grasping ability of locusts on slopes with varying levels of roughness. The grasping morphologies of locusts' bodies and tarsi were observed, and the surface roughness as well as diameters of their claw tips was measured under a microscope to account for the grasping mechanism of these insects on the sloping substrate. The results showed that the claw tips and part of the pads were in contact with the inverted substrate when the mean particle diameter was in the range of 15.3-40.5 µm. The interaction between pads and substrates may improve the stability of contact, and claw tips may play a key role in keeping the attachment reliable. A model was developed to explain the significant effects of the relative size of claw tips and mean particle diameter on grasping ability as well as the observed increase in lateral force (2.09-4.05 times greater than the normal force during detachment) with increasing slope angle, which indicates that the lateral force may be extremely important in keeping the contact reliable. This research lays the groundwork for the probable design and development of biomimetic robotics.

  9. Effects of Crop Canopies on Rain Splash Detachment

    PubMed Central

    Ma, Bo; Yu, Xiaoling; Ma, Fan; Li, Zhanbin; Wu, Faqi

    2014-01-01

    Crops are one of the main factors affecting soil erosion in sloping fields. To determine the characteristics of splash erosion under crop canopies, corn, soybean, millet, and winter wheat were collected, and the relationship among splash erosion, rainfall intensity, and throughfall intensity under different crop canopies was analyzed through artificial rainfall experiments. The results showed that, the mean splash detachment rate on the ground surface was 390.12 g/m2·h, which was lower by 67.81% than that on bare land. The inhibiting effects of crops on splash erosion increased as the crops grew, and the ability of the four crops to inhibit splash erosion was in the order of winter wheat>corn>soybeans>millet. An increase in rainfall intensity could significantly enhance the occurrence of splash erosion, but the ability of crops to inhibit splash erosion was 13% greater in cases of higher rainfall intensity. The throughfall intensity under crop canopies was positively related to the splash detachment rate, and this relationship was more significant when the rainfall intensity was 40 mm/h. Splash erosion tended to occur intensively in the central row of croplands as the crop grew, and the non-uniformity of splash erosion was substantial, with splash erosion occurring mainly between the rows and in the region directly under the leaf margin. This study has provided a theoretical basis for describing the erosion mechanisms of cropland and for assisting soil erosion prediction as well as irrigation and fertilizer management in cultivated fields. PMID:24992386

  10. Reinterpretation of Mormon Peak detachment in Mormon Mountains, southern Nevada

    SciTech Connect

    Carpenter, J.A.

    1988-02-01

    Brian Wernicke proposed that the Meadow Valley Mountains are part of a west-directed Mormon Peak extensional allochthon and that low-angle normal faults control basin-and-range structure. He suggested the Meadow Valley Mountains detached off the Mormon Mountains and moved 20 km during the middle to late Miocene, along a low-angle normal fault - the Mormon Peak detachment - dipping 20/degrees/-25/degrees/ west. In this interpretation, the updip source area for the paleozoic klippen of the Mormon Peak extensional allochthon now exposed in the Mormon Mountains requires an origin from heights greater than 9 km (30,000 ft) above the present Virgin Valley basin. K-Ar and seismic reflection data document syntectonic sedimentary in-filling of the Virgin Valley basin beginning during the early Oligocene in response to the high-angle (60/degrees/) Virgin-Beaver Dam Mountains normal fault. Klippen of the purported Mormon Peak extensional allochthon that veneer the Mormon Mountains represent gravity-slide blocks that have source areas within the Mormon Mountains and require only 0.5-4 km displacements. These gravity-slide blocks moved in various downslope directions on rootless denudational faults resulting from the loss of lateral support because of high-angle basin-range faulting and associated erosion. Detailed mapping of Wernicke's easternmost klippe of the Mormon Peak extensional allochthon reveals east-vergent structural features rather than west-vergent, as necessary in his uniform sense-core complex model. Geologic and geophysical data show that high-angle normal faults exert primary control over basin-and-range structure, whereas gravitational sliding is a secondary surficial (rootless) feature of minor significance.

  11. High subretinal fluid procoagulant activity in rhegmatogenous retinal detachment.

    PubMed

    Ricker, Lukas J A G; Dieri, Raed Al; Beckers, Gerold J M; Pels, Elisabeth; Liem, Albert T A; Hendrikse, Fred; Kijlstra, Aize; Hemker, H Coenraad; La Heij, Ellen C

    2010-10-01

    An increased mRNA expression of genes related to blood coagulation has been demonstrated in an experimental retinal detachment model but has not yet been confirmed in human clinical specimens. Tissue factor (TF), the initiating factor of blood coagulation, may be a determinant of the extent of tissue injury after rhegmatogenous retinal detachment (RRD). This study was conducted to determine whether subretinal fluid and vitreous fluid collected from patients with RRD have a procoagulant effect. Calibrated thrombin generation (CAT) was used to investigate the thrombogenic properties of 28 subretinal fluids collected during scleral buckling surgery for RRD. Further, the thrombogenic properties of vitreous fluids from RRD (n = 12), macular pucker (n = 5), macular hole (n = 6), and proliferative diabetic retinopathy (n = 5) were compared with the properties of eye bank eyes (n = 11), which served as control specimens. The procoagulant activity of TF was determined with Western blot analysis. The addition of subretinal fluid from all RRD patients (28/28, 100%) induced thrombin generation in normal and severely factor (F)XII-deficient plasma. Contrary to the subretinal fluid, the addition of vitreous fluids from various ocular disorders evoked very little thrombin generation in normal and severely FXII-deficient plasma (4/12, 33% RRD; 1/5, 20% macular pucker; 0/6, 0% macular hole; 0/5, 0% proliferative diabetic retinopathy; and 2/11, 18% eye bank eyes). The procoagulant activity in subretinal fluid was almost completely neutralized by antibodies against human TF. The presence of TF in subretinal fluid was confirmed by Western blot. Subretinal fluid of patients with RRD induces high procoagulant activity, determined by measuring the level of tissue factor.

  12. Surgical challenges and outcomes of rhegmatogenous retinal detachment in albinism.

    PubMed

    Sinha, M K; Chhablani, J; Shah, B S; Narayanan, R; Jalali, S

    2016-03-01

    To report the outcomes and surgical difficulties during rhegmatogenous retinal detachment (RRD) repair in patients with albinism. Retrospective analysis of 10 eyes of 9 patients with albinism that underwent RRD repair was performed. Collected data included demographic details, preoperative examination details, surgical procedure, surgical difficulties, anatomical, and visual outcomes. Outcome measures were retinal reattachment and visual acuity at the last follow-up. Mean preoperative best-corrected visual acuity (BCVA) was logMAR (Logarithm of the Minimum Angle of Resolution) 2.15 (range 0.9-3.0) with preoperative localization of causative break in six eyes. One eye had proliferative vitreoretinopathy grade C1 preoperatively. Four eyes underwent scleral buckling (SB) and six underwent 20G pars plana vitrectomy (PPV) with silicone oil injection. Intraoperative complication as iatrogenic retinal break occurred in four eyes. For retinopexy during vitrectomy, endolaser delivery was possible in three out of six eyes, whereas three eyes had cryopexy. The mean follow-up was 12 months in SB group (range 1-12; median 12 months) and 5.33 months (range 1-12; median 3 months) in PPV group. Among vitrectomized eye, two eyes had recurrence at 3 months with oil in situ. Rest of the eyes had attached retina at last follow-up. Mean BCVA at last follow-up was logMAR -1.46 (range 0.7-2.0) with mean improvement of -0.57 logMAR. Identification of break, induction of posterior vitreous detachment, and endolaser delivery may be difficult during RRD repair in patients with albinism. The incidence of PVR appeared less in these eyes. Both SB and PPV were efficacious and appear to be good surgical techniques for use in this patient population.

  13. Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

    PubMed Central

    Schwartz, Stephen G; Flynn, Harry W; Lee, Wen-Hsiang; Wang, Xue

    2014-01-01

    Background Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery to restore normal anatomy and to stabilize or improve vision. PVR usually occurs in association with recurrent RD (that is, after initial retinal re-attachment surgery) but occasionally may be associated with primary RD. Either way, a tamponade agent (gas or silicone oil) is needed during surgery to reduce the rate of postoperative recurrent RD. Objectives The objective of this review was to assess the relative safety and effectiveness of various tamponade agents used with surgery for retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR). Search methods We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 26 June 2013. Selection criteria We included randomized controlled trials (RCTs) of participants undergoing surgery for RD associated with PVR that compared various tamponade agents. Data collection and analysis Two review authors screened the search results independently. We used the standard methodological procedures expected by The Cochrane Collaboration. PMID:24532038

  14. Rocket dust storms and detached layers in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Spiga, A.; Faure, J.; Madeleine, J.; Maattanen, A. E.; Forget, F.

    2012-12-01

    Airborne dust is the main climatic agent in the Martian environment. Local dust storms play a key role in the dust cycle; yet their life cycle is poorly known. Here we use mesoscale modeling with radiatively-active transported dust to predict the evolution of a local dust storm monitored by OMEGA onboard Mars Express. We show that the evolution of this dust storm is governed by deep convective motions. The supply of convective energy is provided by the absorption of incoming sunlight by dust particles, in lieu of latent heating in moist convection on Earth. We propose to use the terminology "rocket dust storm", or conio-cumulonimbus, to describe those storms in which rapid and efficient vertical transport takes place, injecting dust particles at high altitudes in the Martian troposphere (30 to 50 km). Combined to horizontal transport by large-scale winds, rocket dust storms form detached layers of dust reminiscent of those observed with instruments onboard Mars Global Surveyor and Mars Reconnaissance Orbiter. Detached layers are stable over several days owing to nighttime sedimentation being unable to counteract daytime convective transport, and to the resupply of convective energy at sunrise. The peak activity of rocket dust storms is expected in low-latitude regions at clear season, which accounts for the high-altitude tropical dust maximum unveiled by Mars Climate Sounder. Our findings on dust-driven deep convection have strong implications for the Martian dust cycle, thermal structure, atmospheric dynamics, cloud microphysics, chemistry, and robotic and human exploration.ensity-scaled dust optical depth at local times 1400 1600 and 1800 (lat 2.5°S, Ls 135°) hortwave heating rate at local time 1500 and latitude 2.5°S.

  15. Large-scale Quaternary detachments in Ventura Basin, southern California

    NASA Astrophysics Data System (ADS)

    Yeats, Robert S.

    1983-01-01

    The Ventura basin is an east-north-east trending trough in the California Transverse Ranges which records major Quaternary detachment faulting at three levels. The earliest thrusting occurred along weak siltstone interbeds in a sequence dominated by competent basin-plain turbidite sandstone. Because sedimentation continued during thrusting, the age, rate, and direction of thrusting can be worked out. Faulting began 1.3 m.y. ago and ceased 0.65 m.y. ago, with a maximum slip rate of 2.8 mm/yr to the southeast. The fault set moved up a 45° ramp and ended as a blind thrust. The ramp had topographic expression on the seafloor, diverting turbidites around the ramp and preserving ash beds along with other hemipelagic sediments on its crest. Following the end of deposition 0.2 m.y. ago, the competent basin-plain turbidites underwent flexural slip folding over an incompetent Miocene sequence dominated by shale; underlying competent Paleogene strata were not folded. The south flank of the Ventura Avenue anticline tilted at 3.4 μrad/yr, the anticlinal crest rose at a rate of 15-16 mm/yr decelerating to 4.3-5.2 mm/yr, and the anticline and an adjacent syncline shortened at a rate of 20 mm/yr. The high rate of folding in the Ventura Avenue oil field resulted in overpressured sandstone reservoirs and oil-water interfaces which have not had time to reach gravity equilibrium. The Red Mountain, San Cayetano, and Santa Susana faults mark the surface expression of a seismically active midcrustal detachment which produced convergence across the Ventura basin at rates as high as 23 mm/yr. Total convergence across the eastern San Cayetano fault near Fillmore is 11,600±2000 m in the last million years.

  16. Targeting CCR3 to Reduce Amyloid-β Production, Tau Hyperphosphorylation, and Synaptic Loss in a Mouse Model of Alzheimer's Disease.

    PubMed

    Zhu, Chunyan; Xu, Bing; Sun, Xiaohong; Zhu, Qiwen; Sui, Yi

    2016-11-23

    The majority of Alzheimer's disease (AD) patients have a late onset, and chronic neuroinflammation, characterized by glial activation and secretion of pro-inflammatory cytokines and chemokines, plays a role in the pathogenesis of AD. The chemokine CCL11 has been shown to be a causative factor of cognitive decline in the process of aging, but little is known whether it is involved in the pathogenesis of AD. In the present study, we showed that CCR3, the receptor for CCL11, was expressed by hippocampal neurons and treatment of primary hippocampal neuronal cultures (14 days in vitro) with CCL11 resulted in activation of cyclin-dependent kinase 5 and glycogen synthase kinase-3β, associated with elevated tau phosphorylation at multiple sites. CCL11 treatment also induced the production of Aβ and dendritic spine loss in the hippocampal neuronal cultures. All these effects were blocked by the CCR3 specific antagonist, GW766994. An age-dependent increase in CCL11, predominantly expressed by the activated microglia, was observed in the cerebrospinal fluid of both APP/PS1 double transgenic mice and wild-type (WT) littermates, with a markedly higher level in APP/PS1 double transgenic mice than that in WT littermates. Deletion of CCR3 in APP/PS1 double transgenic mice significantly reduced the phosphorylation of CDK5 and GSK3β, tau hyperphosphorylation, Aβ deposition, microgliosis, astrogliosis, synaptic loss, and spatial learning and memory deficits. Thus, the age-related increase in CCL11 may be a risk factor of AD, and antagonizing CCR3 may bring therapeutic benefits to AD.

  17. Exendin-4, a glucagon-like peptide-1 receptor agonist, reduces Alzheimer disease-associated tau hyperphosphorylation in the hippocampus of rats with type 2 diabetes.

    PubMed

    Xu, Weijie; Yang, Yan; Yuan, Gang; Zhu, Wenjun; Ma, Delin; Hu, Shuhong

    2015-02-01

    Impaired insulin signaling pathway in the brain in type 2 diabetes (T2D) is a risk factor for Alzheimer disease (AD). Glucagon-like peptide-1 (GLP-1) and its receptor agonist are widely used for treatment of T2D. Here we studied whether the effects of exendin-4 (EX-4), a long-lasting GLP-1 receptor agonist, could reduce the risk of AD in T2D. Type 2 diabetes rats were injected with EX-4 for 28 consecutive days. Blood glucose and insulin levels, as well as GLP-1 and insulin in cerebrospinal fluid, were determined during the experiment. The phosphorylation level of tau at individual phosphorylation sites, the activities of phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT), and glycogen synthase kinase-3β (GSK-3β) were analyzed with Western blots. The levels of phosphorylated tau protein at site Ser199/202 and Thr217 level in the hippocampus of T2D rats were found to be raised notably and evidently decreased after EX-4 intervention. In addition, brain insulin signaling pathway was ameliorated after EX-4 treatment, and this result was reflected by a decreased activity of PI3K/AKT and an increased activity of GSK-3β in the hippocampus of T2D rats as well as a rise in PI3K/AKT activity and a decline in GSK-3β activity after 4 weeks intervention of EX-4. These results demonstrate that multiple days with EX-4 appears to prevent the hyperphosphorylation of AD-associated tau protein due to increased insulin signaling pathway in the brain. These findings support the potential use of GLP-1 for the prevention and treatment of AD in individuals with T2D.

  18. The Detached Bridgman Process: Application for the Growth of Low-Defect Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Croell, A.; Dold, P.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    During crystal growth in the vertical Bridgman process, both the melt and the growing crystal are in contact with the ampoule wall. The different thermal coefficients of expansion of the crystal and the ampoule wall can lead to stresses, crystal defects, and not rarely to cracks and/or polycrystalline growth in the crystal. The detached Bridgman process is characterized by the fact that the melt meniscus frees itself from the ampoule wall and the crystal can be grown without wall contact with the ampoule. After the effect of detachment was observed due to the reduced force of gravity during the early experiments under microgravity conditions, in the past few years the Bridgman process likewise has been successfully used to grow at least partially detached under 1g-condition. If the requirements for detaching the melt meniscus from the ampoule wall are not fulfilled by the material-specific parameters (like e.g. wetting behavior between ampoule and melt and the growth angle of the crystal), detachment can be obtained also by the imposition of suitable pressure ratios in the growth ampoule. In the context of this paper, the growth of germanium by the detached and vertical Bridgman processes in pyrolytic boron nitride crucibles will be reported, Typical gap widths between ampoule wall and detached grown crystals are approximately 10-50 microns. Compared to the crystals grown with wall contact, a reduction of the etch pit density of approximately two orders of magnitude could be obtained by growing with the detached process.

  19. Psychological Detachment Mediating the Daily Relationship between Workload and Marital Satisfaction

    PubMed Central

    Germeys, Lynn; De Gieter, Sara

    2017-01-01

    Scholars already demonstrated that psychologically detaching from work after workhours can diminish or avoid the negative effects of job demands on employees' well-being. In this study, we examined a curvilinear relationship between workload and psychological detachment. Moreover, we investigated the moderating influence of an employee's work-home segmentation preference on the relation between detachment and marital satisfaction. In addition, we applied and extended the stressor-detachment model by examining detachment as a mediator of the relation between workload and marital satisfaction. A total of 136 employees participated in our daily diary survey study during 10 consecutive working days. The results of the Bayesian 2-level path analyses revealed a negative linear and curvilinear relationship between workload and psychological detachment on a daily basis. Daily detachment positively related to marital satisfaction, with one's preference to segment work from home reinforcing this relationship. Moreover, psychological detachment fully mediated the daily relationship between workload and marital satisfaction. Implications for practice and suggestions for future research are discussed. PMID:28101076

  20. Psychological Detachment Mediating the Daily Relationship between Workload and Marital Satisfaction.

    PubMed

    Germeys, Lynn; De Gieter, Sara

    2016-01-01

    Scholars already demonstrated that psychologically detaching from work after workhours can diminish or avoid the negative effects of job demands on employees' well-being. In this study, we examined a curvilinear relationship between workload and psychological detachment. Moreover, we investigated the moderating influence of an employee's work-home segmentation preference on the relation between detachment and marital satisfaction. In addition, we applied and extended the stressor-detachment model by examining detachment as a mediator of the relation between workload and marital satisfaction. A total of 136 employees participated in our daily diary survey study during 10 consecutive working days. The results of the Bayesian 2-level path analyses revealed a negative linear and curvilinear relationship between workload and psychological detachment on a daily basis. Daily detachment positively related to marital satisfaction, with one's preference to segment work from home reinforcing this relationship. Moreover, psychological detachment fully mediated the daily relationship between workload and marital satisfaction. Implications for practice and suggestions for future research are discussed.

  1. Attainment of a stable, fully detached plasma state in innovative divertor configurations

    NASA Astrophysics Data System (ADS)

    Umansky, M. V.; LaBombard, B.; Brunner, D.; Rensink, M. E.; Rognlien, T. D.; Terry, J. L.; Whyte, D. G.

    2017-05-01

    A computational study of long-legged tokamak divertor configurations is performed with the edge transport code UEDGE. Several divertor configurations are considered, with radially or vertically extended, tightly baffled, outer divertor legs and with or without a secondary X-point in the divertor leg volume. For otherwise identical conditions, a scan of the input power from the core plasma is performed. As the power is reduced to a threshold value, the plasma in the outer leg transitions to a fully detached state, which defines the upper limit on the power for detached divertor operation. Reducing the power further results in the detachment front shifting upstream but remains stable. At low power, the detachment front eventually moves all the way to the primary X-point, which is usually associated with degradation of the core plasma, and this defines the lower limit on the power for the detached divertor operation. For the studied parameters, for long-legged divertors, the detached operation window is quite large, in particular, for the X-point target configuration using a secondary X-point in the divertor leg volume, allowing a factor of 5-10 variations in the input power. For the same parameters, for the standard divertor configuration, the detached operation window is very small or even non-existent. The present modeling results suggest the possibility of stable fully detached divertor operation for a tokamak with tightly baffled extended divertor legs.

  2. Visual and electronic comparisons of detached strawberry leaves inoculated with two Colletotrichum species

    USDA-ARS?s Scientific Manuscript database

    Inoculation of detached strawberry leaves with Colletotrichum species may provide an accurate, rapid, non-destructive method of identifying anthracnose resistant germplasm. The purpose of this study was to compare two methods for screening anthracnose resistance. Detached leaves of 60 susceptible an...

  3. Soil detachment by overland flow under different vegetation restoration models in the loess plateau of China

    USDA-ARS?s Scientific Manuscript database

    Land use change has significant effects on soil properties and vegetation cover and thus probably affects soil detachment by overland flow. Few studies were conducted to evaluate the effect of restoration models on the soil detachment process in the Loess Plateau in the past decade during which a Gr...

  4. Temporal variation in soil detachment under different land uses in the Loess Plateau of China

    USDA-ARS?s Scientific Manuscript database

    Measurements of temporal variations in soil detachability under different land uses are badly needed to develop new algorithms or evaluate the existing ones for temporal adjustment of soil detachability in continuous soil erosion models. Few studies were conducted in the Loess Plateau to quantify te...

  5. Detachment from Parents, Problem Behaviors, and the Moderating Role of Parental Support among Italian Adolescents

    ERIC Educational Resources Information Center

    Pace, Ugo; Zappulla, Carla

    2013-01-01

    This study examined the relationship of emotional detachment from parents, parental support, and problem behaviors and focused on the unique and common contribution that detachment and parental support made to internalizing and externalizing behavioral problems. A total of 461 young adolescents, 13 to 14 years old ("M" = 13.4;…

  6. Staying Well and Engaged When Demands Are High: The Role of Psychological Detachment

    ERIC Educational Resources Information Center

    Sonnentag, Sabine; Binnewies, Carmen; Mojza, Eva J.

    2010-01-01

    The authors of this study examined the relation between job demands and psychological detachment from work during off-job time (i.e., mentally switching off) with psychological well-being and work engagement. They hypothesized that high job demands and low levels of psychological detachment predict poor well-being and low work engagement. They…

  7. Sudden Death and Bereavement Outcomes: The Impact of Resources on Grief Symptomatology and Detachment.

    ERIC Educational Resources Information Center

    Reed, M. D.

    1993-01-01

    Examined grief, family detachment, and impact of resources following sudden bereavement among family members of victims of suicide and accidental deaths. Most grief-stricken survivors were more detached from family. Self-esteem emerged as strongest predictor of grief and played role in mediating influences of religious participation and exercise…

  8. The Detached Bridgman Process: Application for the Growth of Low-Defect Germanium Crystals

    NASA Technical Reports Server (NTRS)

    Schweizer, M.; Volz, M. P.; Cobb, S. D.; Croell, A.; Dold, P.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    During crystal growth in the vertical Bridgman process, both the melt and the growing crystal are in contact with the ampoule wall. The different thermal coefficients of expansion of the crystal and the ampoule wall can lead to stresses, crystal defects, and not rarely to cracks and/or polycrystalline growth in the crystal. The detached Bridgman process is characterized by the fact that the melt meniscus frees itself from the ampoule wall and the crystal can be grown without wall contact with the ampoule. After the effect of detachment was observed due to the reduced force of gravity during the early experiments under microgravity conditions, in the past few years the Bridgman process likewise has been successfully used to grow at least partially detached under 1g-condition. If the requirements for detaching the melt meniscus from the ampoule wall are not fulfilled by the material-specific parameters (like e.g. wetting behavior between ampoule and melt and the growth angle of the crystal), detachment can be obtained also by the imposition of suitable pressure ratios in the growth ampoule. In the context of this paper, the growth of germanium by the detached and vertical Bridgman processes in pyrolytic boron nitride crucibles will be reported, Typical gap widths between ampoule wall and detached grown crystals are approximately 10-50 microns. Compared to the crystals grown with wall contact, a reduction of the etch pit density of approximately two orders of magnitude could be obtained by growing with the detached process.

  9. Clinical and environmental genotypes of Vibrio vulnificus display distinct, quorum-sensing-mediated, chitin detachment dynamics

    PubMed Central

    Phippen, Britney L.; Oliver, James D.

    2015-01-01

    The ability for bacteria to attach to and detach from various substrata is important for colonization, survival and transitioning to new environments. An opportunistic human pathogen, Vibrio vulnificus, can cause potentially fatal septicemia after ingestion of undercooked seafood. Based on genetic polymorphisms, strains of this species are subtyped into clinical (C) and environmental (E) genotypes. Vibrio vulnificus readily associates with chitin, thus we investigated chitin detachment dynamics in these disparate genotypes. We found that C-genotypes detach significantly more than E-genotypes after 24 hours in aerobic as well as anaerobic conditions. Furthermore, expression of genes involved in type IV pilin production was significantly downregulated in C-genotypes compared to E-genotypes, suggesting an importance in detachment. Interestingly, gbpA, a gene that has been shown to be important in host colonization in V. cholerae, was upregulated in the C-genotypes during detachment. Additionally, we found that C-genotypes detached to a greater extent, and produced more quorum-sensing (QS) autoinducer-2 molecules relative to E-genotypes, which suggests a role for QS in detachment. These findings suggest that for V. vulnificus, QS-mediated detachment may be a potential mechanism for transitioning into a human host for C-genotypes, while facilitating E-genotype maintenance in the estuarine environment. PMID:26377182

  10. Hygro-thermo-mechanical modeling of transport phenomena for simulation of building envelopes detachment

    NASA Astrophysics Data System (ADS)

    Maděra, J.; Koudelka, T.; Kruis, Jaroslav

    2016-12-01

    Plaster detachment is serious problem with strong influence on the structure durability. This contribution describes numerical simulation of the plaster detachment. The simulation is based on the coupled thermo-hydro-mechanical analysis of masonry and plaster. Interface finite elements are used between the masonry and plaster. Material parameters were obtained from laboratory test.

  11. Staying Well and Engaged When Demands Are High: The Role of Psychological Detachment

    ERIC Educational Resources Information Center

    Sonnentag, Sabine; Binnewies, Carmen; Mojza, Eva J.

    2010-01-01

    The authors of this study examined the relation between job demands and psychological detachment from work during off-job time (i.e., mentally switching off) with psychological well-being and work engagement. They hypothesized that high job demands and low levels of psychological detachment predict poor well-being and low work engagement. They…

  12. Spectral domain optical coherence tomography imaging of subretinal bands associated with chronic retinal detachments

    PubMed Central

    Kothari, Nikisha; Kuriyan, Ajay E; Flynn, Harry W

    2016-01-01

    We report three patients with subretinal bands associated with retinal detachment in chronic retinal detachments who underwent successful retinal reattachment. Subretinal bands before and after surgery can be identified on clinical examination and spectral domain optical coherence tomography. Removal of subretinal bands is not mandatory to achieve retinal reattachment. PMID:27099457

  13. Kinetic effects in edge plasma: kinetic modeling for edge plasma and detached divertor

    NASA Astrophysics Data System (ADS)

    Takizuka, T.

    2017-03-01

    Detached divertor is considered a solution for the heat control in magnetic-confinement fusion reactors. Numerical simulations using the comprehensive divertor codes based on the plasma fluid modeling are indispensable for the design of the detached divertor in future reactors. Since the agreement in the results between detached-divertor experiments and simulations has been rather fair but not satisfactory, further improvement of the modeling is required. The kinetic effect is one of key issues for improving the modeling. Complete kinetic behaviors are able to be simulated by the kinetic modeling. In this paper at first, major kinetic effects in edge plasma and detached divertor are listed. One of the most powerful kinetic models, particle-in-cell (PIC) model, is described in detail. Several results of PIC simulations of edge-plasma kinetic natures are presented. Future works on PIC modeling and simulation for the deeper understanding of edge plasma and detached divertor are discussed.

  14. The Development of a Cat Model of Retinal Detachment and Re-attachment.

    PubMed

    Wassmer, Sarah; Leonard, Brian C; Coupland, Stuart G; Baker, Adam; Hamilton, John; Torlone, Renée; Zacks, David N; Tsilfidis, Catherine

    2016-01-01

    We present an optimized surgical technique for feline retinal detachment which allows for natural re-attachment, reduces retinal scarring and vitreal bands, and allows central placement of the detachment in close proximity to the optic nerve. This enables imaging via Optical Coherence Tomography (OCT) and multifocal electroretinography (mfERG) analysis. Ideal detachment conditions involve a lensectomy followed by a three-port pars plana vitrectomy. A 16-20 % retinal detachment is induced by injecting 8 % C3F8 gas into the subretinal space in the central retina with a 42G cannula. The retinal detachment resolves approximately 6 weeks post-surgery. Imaging is enhanced by using a 7.5 and 20 diopter lens for OCT and mfERG fundus imaging, respectively, to compensate for the removed lens.

  15. Characterization of Surface Features in Detached Grown GeSi Crystals

    NASA Technical Reports Server (NTRS)

    Cobb, S. D.; Volz, M. P.; Schweizer, M.; Kaiser, N.; Carpenter, P. K.; Szofran, F. R.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    The growth of detached crystals by the Bridgman technique, in which the growing crystal is not in contact with the crucible wall, has been observed both on earth and in microgravity conditions. At present, the mechanisms contributing to the detachment are not completely understood and until recently detachment has not been reproducibly obtained. It is commonly understood that the main factors that promote the occurrence of detached growth include: high contact angle between the melt and the crucible material, high growth angle, and a pressure difference between the annular gap around the solid below the melt and the volume above the melt along the meniscus. These parameters were varied in Bridgman growth experiments to determine the conditions required to achieve detached growth terrestrially in Ge and GeSi alloys. These experiments are in preparation for experiments on the International Space Station (ISS). The detailed objectives of the flight experiments and a description of the growth methods employed are the subject of another presentation at this Conference. Detached crystals were achieved repeatedly in pyrolytic boron nitride ampoules when a pressure difference was employed. All crystals, except for those grown in fused silica ampoules, were easily removed from their containers, however, this fact alone is not sufficient to infer detached growth. Detachment was verified by comparing profilometer measurements of the radius of the samples with observations of the sample surfaces using optical and electron microscopy. The surfaces of the attached areas of the crystals had the same shape and surface texture as the interior crucible wall. Regions of detached growth contained many unique features and crystal facets could usually be observed. Several of these surface features have been correlated with mechanisms of detachment or free-surface growth and others to processing events or conditions.

  16. Effects of low-Z and high-Z impurities on divertor detachment and plasma confinement

    DOE PAGES

    Wang, H. Q.; Guo, Houyang Y.; Petrie, Thomas W.; ...

    2017-03-18

    The impurity-seeded detached divertor is essential for heat exhaust in ITER and other reactor-relevant devices. Dedicated experiments with injection of N2, Ne and Ar have been performed in DIII-D to assess the impact of the different impurities on divertor detachment and confinement. Seeding with N2, Ne and Ar all promote divertor detachment, greatly reducing heat flux near the strike point. The upstream plasma density at the onset of detachment decreases with increasing impurity-puffing flow rates. For all injected impurity species, the confinement and pedestal pressure are correlated with the impurity content and the ratio of separatrix loss power to themore » L-H transition threshold power. As the divertor plasma approaches detachment, the high-Z impurity seeding tends to degrade the core confinement owing to the increased core radiation. In particular, Ar injection leads to an increase in core radiation, up to 50% of the injected power, and a reduction in pedestal temperature over 60%, thus significantly degrading the confinement, i.e., with H98 reducing from 1.1 to below 0.7. As for Ne seeding, H98 near 0.8 can be maintained during the detachment phase with the pedestal temperature being reduced by about 50%. In contrast, in the N2 seeded plasmas, radiation is predominately confined in the boundary plasma, with up to 50% of heating power being radiated in the divertor region and less than 25% in the core at the onset of detachment. In the case of strong N2 gas puffing, the confinement recovers during the detachment, from ~20% reduction at the onset of the detachment to greater than that before the seeding. The core and pedestal temperatures feature a reduction of 30% from the initial attached phase and remain nearly constant during the detachment phase. The improvement in confinement appears to arise from the increase in pedestal and core density despite the temperature reduction.« less

  17. Effect of 3D magnetic perturbations on divertor conditions and detachment in tokamak and stellarator

    NASA Astrophysics Data System (ADS)

    Ahn, J.-W.; Briesemester, A. R.; Kobayashi, M.; Lore, J. D.; Schmitz, O.; Diallo, A.; Gray, T. K.; Lasnier, C. J.; LeBlanc, B. P.; Maingi, R.; McLean, A. G.; Sabbagh, S. A.; Soukhanovskii, V. A.

    2017-08-01

    Enhanced perpendicular heat and momentum transport induces parallel pressure loss leading to divertor detachment, which can be produced by the increase of density in 2D tokamaks. However, in the 3D configurations such as tokamaks with 3D fields and stellarators, the fraction of perpendicular transport can be higher even in a lower density regime, which could lead to the early transition to detachment without passing through the high-recycling regime. 3D fields applied to the limiter tokamak plasmas produce edge stochastic layers close to the last closed flux surface (LCFS), which can allow for enhanced perpendicular transport and indeed the absence of high recycling regime and early detachment have been observed in TEXTOR and Tore Supra. However, in the X-point divertor tokamaks with the applied 3D fields, the parallel transport is still dominant and the detachment facilitation has not been observed yet. Rather, 3D fields affected detachment adversely under certain conditions, either by preventing detachment onset as seen in DIII-D or by re-attaching the existing detached plasma as shown in NSTX. The possible way for strong 3D effects to induce access to the early detachment in divertor tokamaks appears to be via significant perpendicular loss of parallel momentum by frictional force for the counter-streaming flows between neighboring flow channels in the divertor. In principle, the adjacent lobes in the 3D divertor tokamak may generate the counter-streaming flow channels. However, an EMC3-EIRENE simulation for ITER H-mode plasmas demonstrated that screened RMP leads to significantly reduced counter-flows near the divertor target, therefore the momentum loss effect leading to detachment facilitation is expected to be small. This is consistent with the observation in LHD, which showed screening (amplification) of RMP fields in the attachment (stable detachment) case. Work for optimal parameter window for best divertor operation scenario is needed particularly for

  18. Detached Bridgman Growth of Germanium and Germanium-Silicon Alloy Crystals

    NASA Technical Reports Server (NTRS)

    Szofran, F. R.; Volz, M. P.; Schweizer, M.; Cobb, S. D.; Motakef, S.; Croell, A.; Dold, P.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Earth based experiments on the science of detached crystal growth are being conducted on germanium and germanium-silicon alloys (2 at% Si average composition) in preparation for a series of experiments aboard the International Space Station (ISS). The purpose of the microgravity experiments includes differentiating among proposed mechanisms contributing to detachment, and confirming or refining our understanding of the detachment mechanism. Because large contact angle are critical to detachment, sessile drop measurements were used to determine the contact angles as a function of temperature and composition for a large number of substrates made of potential ampoule materials. Growth experiments have used pyrolytic boron nitride (pBN) and fused silica ampoules with the majority of the detached results occurring predictably in the pBN. The contact angles were 173 deg (Ge) and 165 deg (GeSi) for pBN. For fused silica, the contact angle decreases from 150 deg to an equilibrium value of 117 deg (Ge) or from 129 deg to an equilibrium value of 100 deg (GeSi) over the duration of the experiment. The nature and extent of detachment is determined by using profilometry in conjunction with optical and electron microscopy. The stability of detachment has been analyzed, and an empirical model for the conditions necessary to achieve sufficient stability to maintain detached growth for extended periods has been developed. Results in this presentation will show that we have established the effects on detachment of ampoule material, pressure difference above and below the melt, and silicon concentration; samples that are nearly completely detached can be grown repeatedly in pBN.

  19. Carbonate pseudotachylite? from a Miocene extensional detachment, W. Cyclades, Greece.

    NASA Astrophysics Data System (ADS)

    Rice, A. Hugh N.; Grasemann, Bernhard

    2016-04-01

    Most pseudotachylites, both impact- and fault-related, occur in silicate-rich rocks, typically with 'granitoid' compositions. Examples of melting in carbonate rocks, excluding magmatic sources, are restricted to impact-events, except for a carbonate pseudotachylite in the Canalone Fault, S. Italy (Viganò et al. 2011). Another potential example of carbonate pseudotachylite, shown here, comes from the Miocene-aged W. Cycladic Detachment System, in Greece. Top-SSE ductile to brittle movement on this detachment, with a maximum displacement estimated at tens of kilometers, exhumed of HP-rocks. The carbonate pseudotachylite occurs within an <200 mm thick zone of cataclasites developed between footwall carbonate ultramylonites, containing thin layers and cm-scale boudins of quartzite, and hanging wall breccias; no contacts with the footwall ultramylonites or hanging wall breccias has been found (yet). The cataclasite zone, which can be traced along-strike for at least 90 m, over ~20 m elevation, comprises several distinct layers. In the sample described, five layers occur. The lowest (A; >43 mm thick), consists of dark (hematitic) red, ultra-fine grained unlayered carbonate with up to 40x10 mm rather rounded clasts of earlier generations of cataclasite, many with a quartzite composition. These clasts are fractured and partially separated, with a fine red carbonate matrix. No layering of the matrix or clasts is apparent. The clasts become finer and more abundant towards the boundary with Layer B. Layers B and D (~57 & ~20 mm thick) dominantly comprises protocataclasite with greyish quartz fragments separated by a carbonate matrix along narrow fractures. Zone C and E (~23 m & >15 mm thick) comprise pale pink carbonate-dominated rocks with abundant <30x5 mm-sized red carbonate clasts (+/- quartz fragments) of earlier cataclasite generations. These elongate clasts lie parallel to the overall banding, which is parallel to the ultramylonitic foliation (detachment surface

  20. Analysis of Bacterial Detachment from Substratum Surfaces by the Passage of Air-Liquid Interfaces

    PubMed Central

    Gómez-Suárez, Cristina; Busscher, Henk J.; van der Mei, Henny C.

    2001-01-01

    A theoretical analysis of the detachment of bacteria adhering to substratum surfaces upon the passage of an air-liquid interface is given, together with experimental results for bacterial detachment in the absence and presence of a conditioning film on different substratum surfaces. Bacteria (Streptococcus sobrinus HG1025, Streptococcus oralis J22, Actinomyces naeslundii T14V-J1, Bacteroides fragilis 793E, and Pseudomonas aeruginosa 974K) were first allowed to adhere to hydrophilic glass and hydrophobic dimethyldichlorosilane (DDS)-coated glass in a parallel-plate flow chamber until a density of 4 × 106 cells cm−2 was reached. For S. sobrinus HG1025, S. oralis J22, and A. naeslundii T14V-J1, the conditioning film consisted of adsorbed salivary components, while for B. fragilis 793E and P. aeruginosa 974K, the film consisted of adsorbed human plasma components. Subsequently, air bubbles were passed through the flow chamber and the bacterial detachment percentages were measured. For some experimental conditions, like with P. aeruginosa 974K adhering to DDS-coated glass and an air bubble moving at high velocity (i.e., 13.6 mm s−1), no bacteria detached upon passage of an air-liquid interface, while for others, detachment percentages between 80 and 90% were observed. The detachment percentage increased when the velocity of the passing air bubble decreased, regardless of the bacterial strain and substratum surface hydrophobicity involved. However, the variation in percentages of detachment by a passing air bubble depended greatly upon the strain and substratum surface involved. At low air bubble velocities the hydrophobicity of the substratum had no influence on the detachment, but at high air bubble velocities all bacterial strains were more efficiently detached from hydrophilic glass substrata. Furthermore, the presence of a conditioning film could either inhibit or stimulate detachment. The shape of the bacterial cell played a major role in detachment at high

  1. Residual Gas Effects on Detached Solidification in Microgravity

    NASA Technical Reports Server (NTRS)

    Wilcox, William R.; Regel, Liya L.; Ramakrishnan; Kota, Arun; Anand, Gaurav

    2004-01-01

    Our long term goal has been to make detached solidification reproducible, which requires a full understanding of the mechanisms underlying it. Our Moving Meniscus Model of steady-state detachment predicts that it depends strongly on the surface tension of the melt and the advancing contact angle with the ampoule wall. Thus, the objective of the current project was to determine the influence of residual gases on the surface tension and contact angle of molten semiconductors on typical ampoule materials. Our focus was on the influence of oxygen on indium antimonide on clean silica ("quartz"). The research was performed by three chemical engineering graduate students, the third of whom will complete his research in the summer of 2005. Originally, we had planned to use a sealed silica cell containing a zirconia electrochemical element to control the oxygen partial pressure. However, zirconia requires an operating temperature above the 530 C melting point of InSb and is difficult to form a gas-tight seal with silica. Thus, we decided instead to flow an oxygen-containing gas through the cell. A special apparatus was designed, built and perfected. A piece of InSb was placed on a horizontal silica plate in a quartz cell. High purity argon, helium or hydrogen-containing gas is passed continuously through the cell while the oxygen concentration in the effluent gas is measured. The shape of the resulting drop was used to determine contact angle and surface tension of Ga-doped and high purity InSb. Oxygen appeared to decrease the contact angle, and definitely did not increase it. The following section gives the background for the research. Section 2 summarizes the results obtained on Ga-doped InSb with relatively high oxygen concentrations. Section 3 describes recent improvements made to the apparatus and methods of analysis. Section 4 gives recent results for high-purity InSb at low oxygen concentrations. Final results will be obtained only this summer (2005). Each section

  2. Detached parenting and toddler problem behavior in Early Head Start families.

    PubMed

    Jones Harden, Brenda; Denmark, Nicole; Holmes, Allison; Duchene, Melissa

    2014-01-01

    This study examined detached parenting among Early Head Start mothers, and associated maternal characteristics and child behavior. Participants included 81 mother-child dyads. Data were collected in participants' homes during two visits. Mothers reported on demographic factors, parenting stress, and children's problem behaviors. Children's neurodevelopment was assessed, and videotaped parent-child play interactions were coded. Path analyses indicated that demographic risk factors and parenting stress were associated with higher levels of detached parenting. As a mediator, detached parenting significantly predicted children's later problem behavior. There was a direct effect of parenting stress on children's behavior problems, but no direct effect of children's neurodevelopmental risk. Detached parenting partially mediated the influence of parenting stress on children's problem behavior. The final model moderately accounted for the variance in detached parenting and children's problem behaviors. The results suggest that parents who experience multiple risks and high levels of parenting stress are more likely to demonstrate detached parenting. In addition, detached parenting leads to higher levels of toddler problem behavior, and may increase the problem behavior displayed by toddlers of parents experiencing multiple risks and parenting stress. These findings are discussed in the context of infant mental health practice.

  3. Adhesion Upon Solidification and Detachment in the Melt Spinning of Metals

    NASA Astrophysics Data System (ADS)

    Altieri, Anthony L.; Steen, Paul H.

    2014-12-01

    In planar-flow melt spinning, liquid metal is rapidly solidified, against a heat-sink wheel, into thin ribbons which adhere to the substrate wheel. In the absence of a blade to mechanically scrape the ribbon off the wheel, it may wrap fully around and re-enter the solidification region, called `catastrophic' adhesion. Otherwise, detachment occurs part way around the wheel, called `natural' detachment. Natural detachment occurs through a release of thermo-elastic stress after sufficient cooling of the ribbon, according to prior studies. This note extends prior work by invoking a crack propagation view of natural detachment which, when combined with a simple model of the thermo-elastic stress build-up and ribbon cooling, yields an adhesion/detachment criterion characterized by an interfacial adhesion/fracture energy . For aluminum-silicon alloys frozen against a copper substrate, we report 60 N/m. The criterion can be used to predict detachment once a heat-transfer coefficient is known. We obtain this parameter from natural detachment experiments and then use it to predict catastrophic adhesion in a semi-empirical way. Our note puts a quantitative foundation underneath prior qualitative discussions in the literature. Alternatively, it demonstrates how the interfacial strength of adhesion, a property only of the pair of adhering materials, might be measured based on sticking distance experiments.

  4. Changes in membrane conductance play a pathogenic role in osmotic glial cell swelling in detached retinas.

    PubMed

    Wurm, Antje; Pannicke, Thomas; Iandiev, Ianors; Bühner, Eva; Pietsch, Uta-Carolin; Reichenbach, Andreas; Wiedemann, Peter; Uhlmann, Susann; Bringmann, Andreas

    2006-12-01

    Detachment of the neural retina from the pigment epithelium may be associated with tissue edema; however, the mechanisms of fluid accumulation are not understood. Because retinal detachment is usually not accompanied by vascular leakage, we investigated whether the osmotic swelling characteristics of retinal glial (Müller) cells are changed after experimental detachment of the porcine retina. Osmotic stress, induced by application of a hypotonic bath solution to retinal slices, caused swelling of Müller cell bodies in 7-day-detached retinas, but no swelling was inducible in slices of control retinas. Müller cell somata in slices of retinal areas that surround local detachment in situ also showed osmotic swelling, albeit at a smaller amplitude. The amplitude of osmotic Müller cell swelling correlated with the decrease in the K+ conductance, suggesting a causal relationship between both gliotic alterations. Further factors implicated in Müller cell swelling were inflammatory mediators and oxidative stress. We propose that a dysregulation of the ion and water transport through Müller cells may impair the fluid absorption from the retinal tissue, resulting in chronic fluid accumulation after detachment. This knowledge may lead to a better understanding of the mechanisms involved in retinal degeneration after detachment.

  5. Coupled factors influencing detachment of nano- and micro-sized particles from primary minima

    NASA Astrophysics Data System (ADS)

    Shen, Chongyang; Lazouskaya, Volha; Jin, Yan; Li, Baoguo; Ma, Zhiqiang; Zheng, Wenjuan; Huang, Yuanfang

    2012-06-01

    This study examined the detachments of nano- and micro-sized colloids from primary minima in the presence of cation exchange by laboratory column experiments. Colloids were initially deposited in columns packed with glass beads at 0.2 M CaCl2 in the primary minima of Derjaguin-Landau-Verwey-Overbeek (DLVO) interaction energies. Then, the columns were flushed with NaCl solutions with different ionic strengths (i.e., 0.001, 0.01, 0.1 and 0.2 M). Detachments were observed at all ionic strengths and were particularly significant for the nanoparticle. The detachments increased with increasing electrolyte concentration for the nanoparticle whereas increased from 0.001 M to 0.01 M and decreased with further increasing electrolyte concentration for the micro-sized colloid. The observations were attributed to coupled influence of cation exchange, short-range repulsion, surface roughness, surface charge heterogeneity, and deposition in the secondary minima. The detachments of colloids from primary minima challenge the common belief that colloid interaction in primary minimum is irreversible and resistant to disturbance in solution ionic strength and composition. Although the significance of surface roughness, surface charge heterogeneity, and secondary minima on colloid deposition has been widely recognized, our study implies that they also play important roles in colloid detachment. Whereas colloid detachment is frequently associated with decrease of ionic strength, our results show that increase of ionic strength can also cause detachment due to influence of cation exchange.

  6. Ex vivo comparative study on three sinus lift tools for transcrestal detaching maxillary sinus mucosa.

    PubMed

    Li, Yanfeng; Hu, Pin; Han, Yishi; Fan, Jiadong; Dong, Xinming; Ren, Huan; Yang, Chunhao; Shi, Tingting; Xia, Dong

    2017-07-04

    The objective of this study was to comparatively evaluate 3 different sinus lift tools, namely umbrella-shaped sinus lift curette YSL-04, our recently designed probe-improved sinus lift curettes, and our newly invented elevator 014, using our previous developed goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time. Goat ex vivo models for direct visualizing the effectiveness of detaching sinus mucosa in real time were generated according to our previously developed protocol. The effectiveness for each tool was evaluated through the length of sinus mucosa detached in mesial and distal directions or buccal and palatal directions, and the space volume created by detaching maxillary sinus mucosa in mesial, distal, buccal and palatal directions. The results showed that all 3 sinus lift tools could transcrestally detach the maxillary sinus mucosa and create extra space under the elevated sinus floor on the goat ex vivo sinus models. Moreover, our newly invented elevator 014 had advantages over the other 2 in term of the capability to detach the sinus mucosa. Our newly invented elevator 014 might be a promising tool for detaching maxillary sinus mucosa in transcrestal maxillary sinus floor elevation.

  7. Quaternary low-angle slip on detachment faults in Death Valley, California

    USGS Publications Warehouse

    Hayman, N.W.; Knott, J.R.; Cowan, D.S.; Nemser, E.; Sarna-Wojcicki, A. M.

    2003-01-01

    Detachment faults on the west flank of the Black Mountains (Nevada and California) dip 29??-36?? and cut subhorizontal layers of the 0.77 Ma Bishop ash. Steeply dipping normal faults confined to the hanging walls of the detachments offset layers of the 0.64 Ma Lava Creek B tephra and the base of 0.12-0.18 Ma Lake Manly gravel. These faults sole into and do not cut the low-angle detachments. Therefore the detachments accrued any measurable slip across the kinematically linked hanging-wall faults. An analysis of the orientations of hundreds of the hanging-wall faults shows that extension occurred at modest slip rates (<1 mm/yr) under a steep to vertically oriented maximum principal stress. The Black Mountain detachments are appropriately described as the basal detachments of near-critical Coulomb wedges. We infer that the formation of late Pleistocene and Holocene range-front fault scarps accompanied seismogenic slip on the detachments.

  8. Hypotony and ciliochoroidal detachment following pharmacologic aqueous suppressant therapy in previously filtered patients.

    PubMed

    Vela, M A; Campbell, D G

    1985-01-01

    This is the first report describing the syndrome of hypotony and ciliochoroidal detachment following pharmacologic aqueous suppressant therapy in previously filtered eyes. Four patients had a history of advanced primary open-angle glaucoma treated with multiple medical therapies, including timolol for 11 to 36 months. They then underwent filtration surgery, which failed in two cases. Timolol and/or acetazolamide therapy was instituted 1 to 18 months following surgery. The patients then developed hypotony and ciliochoroidal detachment, which resolved spontaneously after cessation of the pharmacologic aqueous suppressant therapy. In three of the cases, the episode of hypotony and ciliochoroidal detachment recurred after a second challenge with timolol and/or acetazolamide therapy. Inflammation, tumor, wound leakage, retinal detachment and cyclodialysis cleft were excluded. A mechanism of formation of ciliochoroidal detachment in this syndrome is proposed. Long-term timolol therapy followed by filtration surgery and its attendant postoperative hypotony and ciliochoroidal detachment sensitizes the ciliary epithelium. Subsequent pharmacologic aqueous suppressant therapy results in almost total reduction of aqueous production, causing hypotony and ciliochoroidal detachment.

  9. Achieving temporary divertor plasma detachment with MARFE events by pellet injection in the EAST superconducting tokamak

    NASA Astrophysics Data System (ADS)

    Guozhong, Deng; Liang, Wang; Xiaoju, Liu; Yanmin, Duan; Jiansheng, Hu; Changzheng, Li; Ling, Zhang; Shaocheng, Liu; Huiqian, Wang; Liang, Chen; Jichan, Xu; Wei, Feng; Jianbin, Liu; Huan, Liu; Guosheng, Xu; Houyang, Guo; Xiang, Gao; the EAST Team

    2017-01-01

    A new pellet injection system has been equipped on the experimental advanced superconducting tokamak (EAST) in the 2012 campaign, with a pellet size of ϕ 2 mm × 2 mm, a frequency of 1 Hz-10 Hz and velocity of 150 m s-1-300 m s-1. The deuterium pellet is well-known for plasma fuelling as well as for triggering the edge localized mode (ELM). In the 2012 campaign, pellet injection experiments were successfully carried out on EAST. Temporary plasma detachment achieved by deuterium pellets has been observed in a double null (DN) divertor configuration, with multi-pellet injections at a repetition frequency of 2 Hz. The partial detachment of the outer divertors and complete detachment of the inner divertors was achieved after 35 ms of each pellet injection, which have a duration of 30-60 ms with the maximum degree of detachment (DOD) reaching 3.5 and 37, respectively. Meanwhile, the multifaceted asymmetric radiation from the edge (MARFE) phenomena was also observed at the high field side (HFS) near both the lower and upper X-points with radiation loss suddenly increased to about 15%-70%, which may be the main cause of divertor plasma detachment. The temporary detachment induced by pellet injection may act as a new way to study divertor detachment behaviors.

  10. Quantifying micron-scale grain detachment during weathering experiments on limestone

    NASA Astrophysics Data System (ADS)

    Levenson, Yael; Emmanuel, Simon

    2016-01-01

    Weathering in carbonate rocks is often assumed to be governed by chemical dissolution. Nevertheless, chemical processes can be coupled to mechanical mechanisms, with small grains undergoing partial dissolution along grain boundaries, followed by detachment from the rock surface. Crucially, this process can even extend down to the micron-scale. Although chemo-mechanical detachment could be critical for the understanding of carbonate weathering at the global scale, the role it plays has not been directly quantified. To calculate the contribution of grain detachment to surface retreat rates, and to determine the impact of the flow regime, we carried out a series of flow-through weathering experiments on micritic limestone. Using atomic force microscopy, we obtained high resolution in situ data of surface topography for reacting rock surfaces. In all the experiments, both grain detachment and chemical dissolution were observed. Under the laminar flow conditions we explored, we found no clear correlation between flow rate and the size of detached grains, or between the flow rate and the frequency of grain detachment events. Importantly, our results establish that grain detachment contributes significantly to the overall surface retreat, on average accelerating mass loss by 38%. In addition to speeding up weathering, this micron-scale mechanism could also influence the evolution of porosity in aquifers and hydrocarbon reservoirs, and provide a natural flux of colloids that could transport heavy metals or radionuclides in groundwater.

  11. Biofilm formation on polystyrene in detached vs. planktonic cells of polyhydroxyalkanoate-accumulating Halomonas venusta.

    PubMed

    Berlanga, Mercedes; Domènech, Òscar; Guerrero, Ricardo

    2014-12-01

    Biofilm development is characterized by distinct stages of initial attachment, microcolony formation and maturation (sessile cells), and final detachment (dispersal of new, planktonic cells). In this work we examined the influence of polyhydroxyalkanoate (PHA) accumulation on bacterial surface properties and biofilm formation on polystyrene in detached vs. planktonic cells of an environmental strain isolated from microbial mats, Halomonas venusta MAT28. This strain was cultured either in an artificial biofilm in which the cells were immobilized on alginate beads (sessile) or as free-swimming (planktonic) cells. For the two modes of growth, conditions allowing or preventing PHA accumulation were established. Cells detached from alginate beads and their planktonic counterparts were used to study cell surface properties and cellular adhesion on polystyrene. Detached cells showed a slightly higher affinity than planktonic cells for chloroform (Lewis-acid) and a greater hydrophobicity (affinity for hexadecane and hexane). Those surface characteristics of the detached cells may explain their better adhesion on polystyrene compared to planktonic cells. Adhesion to polystyrene was not significantly different between H. venusta cells that had accumulated PHA vs. those that did not. These observations suggest that the surface properties of detached cells clearly differ from those of planktonic cells and that for at least the first 48 h after detachment from alginate beads H. venusta retained the capacity of sessile cells to adhere to polystyrene and to form a biofilm. Copyright© by the Spanish Society for Microbiology and Institute for Catalan Studies.

  12. Electrowetting-on-dielectric assisted bubble detachment in a liquid film

    NASA Astrophysics Data System (ADS)

    Wang, S.; Chen, H. H.; Chen, C. L.

    2016-05-01

    Drawing inspiration from electrowetting-controlled droplets, the potential advantages of electrowetting for bubble dynamics are investigated experimentally. In this study, we present and characterize an open electrowetting-on-dielectric (EWOD) system for studying the bubble behavior. Both detachment and non-detachment processes of a small single bubble in a thick liquid film under EWOD were experimentally observed. The measurement of contact angle changes of the small air bubble shows relatively good agreement with Young-Lippmann's equation within the majority of the test voltage range, except for the saturation region. Meanwhile, we have experimentally demonstrated both the characteristics of single- and double-bubble detachment within a thin liquid film. Direct bubble detachment may occur when it touches the gas-liquid interface during the process of contact angle change, while indirect bubble detachment is highly possible due to the dramatic oscillation resulting from the detachment of adjacent bubbles. The experimental results demonstrate that EWOD can effectively facilitate the detachment of small air bubble in a thin liquid film.

  13. United States Army Reserve in Operation Desert Storm. Strategic Intelligence Support: Military Intelligence Detachments for the Defense Intelligence Agency.

    DTIC Science & Technology

    1991-08-07

    Detachments 4 Qualifications of Unit Members 5 The Outlook for the Detachments 6 The Value of the Detachments 7 Note on Sources 9 End - Notes 10 III~o...comments which improved the accuracy of the paper. Adding Value to the Total Force and to the Nation 9 A Federal Force End - Notes 1. In this paper the term

  14. 31 CFR 358.5 - Which bearer corpora or detached bearer coupons are eligible for conversion to non-transferable...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Which bearer corpora or detached... CORPORA AND DETACHED BEARER COUPONS § 358.5 Which bearer corpora or detached bearer coupons are eligible... associated with the corpus are not submitted with the corpus, the corpus will be converted to a...

  15. 31 CFR 358.4 - Which bearer corpora or detached bearer coupons are eligible for conversion to transferable BECCS...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 2 2010-07-01 2010-07-01 false Which bearer corpora or detached... CORPORA AND DETACHED BEARER COUPONS § 358.4 Which bearer corpora or detached bearer coupons are eligible for conversion to transferable BECCS or CUBES securities? (a) For a callable corpus to be eligible...

  16. 31 CFR 358.8 - Are there fees for the conversion of bearer corpora or detached bearer coupons?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... bearer corpora or detached bearer coupons? 358.8 Section 358.8 Money and Finance: Treasury Regulations... DEBT REGULATIONS GOVERNING BOOK-ENTRY CONVERSION OF BEARER CORPORA AND DETACHED BEARER COUPONS § 358.8 Are there fees for the conversion of bearer corpora or detached bearer coupons? We do not charge...

  17. Neuroprotective effect of novel cognitive enhancer noopept on AD-related cellular model involves the attenuation of apoptosis and tau hyperphosphorylation

    PubMed Central

    2014-01-01

    Background Noopept (N-phenyl-acetyl-L-prolylglycine ethyl ester) was constructed as a dipeptide analog of the standard cognition enhancer, piracetam. Our previous experiments have demonstrated the cognition restoring effect of noopept in several animal models of Alzheimer disease (AD). Noopept was also shown to prevent ionic disbalance, excitotoxicity, free radicals and pro-inflammatory cytokines accumulation, and neurotrophine deficit typical for different kinds of brain damages, including AD. In this study, we investigated the neuroprotective action of noopept on cellular model of AD, Aβ25–35-induced toxicity in PC12 cells and revealed the underlying mechanisms. Results The neuroprotective effect of noopept (added to the medium at 10 μM concentration, 72 hours before Аβ25–35) was studied on Аβ25–35-induced injury (5 μM for 24 h) in PC12 cells. The ability of drug to protect the impairments of cell viability, calcium homeostasis, ROS level, mitochondrial function, tau phosphorylation and neurite outgrowth caused by Аβ25–35 were evaluated. Following the exposure of PC12 cells to Аβ25–35 an increase of the level of ROS, intracellular calcium, and tau phosphorylation at Ser396 were observed; these changes were accompanied by a decrease in cell viability and an increase of apoptosis. Noopept treatment before the amyloid-beta exposure improved PC12 cells viability, reduced the number of early and late apoptotic cells, the levels of intracellular reactive oxygen species and calcium and enhanced the mitochondrial membrane potential. In addition, pretreatment of PC12 cell with noopept significantly attenuated tau hyperphosphorylation at Ser396 and ameliorated the alterations of neurite outgrowth evoked by Аβ25–35. Conclusions Taken together, these data provide evidence that novel cognitive enhancer noopept protects PC12 cell against deleterious actions of Aβ through inhibiting the oxidative damage and calcium overload as well as suppressing

  18. Neuroprotective effect of novel cognitive enhancer noopept on AD-related cellular model involves the attenuation of apoptosis and tau hyperphosphorylation.

    PubMed

    Ostrovskaya, Rita U; Vakhitova, Yulia V; Kuzmina, Uliyana Sh; Salimgareeva, Milyausha Kh; Zainullina, Liana F; Gudasheva, Tatiana A; Vakhitov, Vener A; Seredenin, Sergey B

    2014-08-06

    Noopept (N-phenyl-acetyl-L-prolylglycine ethyl ester) was constructed as a dipeptide analog of the standard cognition enhancer, piracetam. Our previous experiments have demonstrated the cognition restoring effect of noopept in several animal models of Alzheimer disease (AD). Noopept was also shown to prevent ionic disbalance, excitotoxicity, free radicals and pro-inflammatory cytokines accumulation, and neurotrophine deficit typical for different kinds of brain damages, including AD. In this study, we investigated the neuroprotective action of noopept on cellular model of AD, Aβ 25-35-induced toxicity in PC12 cells and revealed the underlying mechanisms. The neuroprotective effect of noopept (added to the medium at 10 μM concentration, 72 hours before Аβ 25-35) was studied on Аβ 25-35-induced injury (5 μM for 24 h) in PC12 cells. The ability of drug to protect the impairments of cell viability, calcium homeostasis, ROS level, mitochondrial function, tau phosphorylation and neurite outgrowth caused by Аβ 25-35 were evaluated. Following the exposure of PC12 cells to Аβ 25-35 an increase of the level of ROS, intracellular calcium, and tau phosphorylation at Ser396 were observed; these changes were accompanied by a decrease in cell viability and an increase of apoptosis. Noopept treatment before the amyloid-beta exposure improved PC12 cells viability, reduced the number of early and late apoptotic cells, the levels of intracellular reactive oxygen species and calcium and enhanced the mitochondrial membrane potential. In addition, pretreatment of PC12 cell with noopept significantly attenuated tau hyperphosphorylation at Ser396 and ameliorated the alterations of neurite outgrowth evoked by Аβ25-35. Taken together, these data provide evidence that novel cognitive enhancer noopept protects PC12 cell against deleterious actions of Aβ through inhibiting the oxidative damage and calcium overload as well as suppressing the mitochondrial apoptotic pathway

  19. Detachment of titanium and fluorohydroxyapatite particles in unloaded endosseous implants.

    PubMed

    Martini, D; Fini, M; Franchi, M; Pasquale, V De; Bacchelli, B; Gamberini, M; Tinti, A; Taddei, P; Giavaresi, G; Ottani, V; Raspanti, M; Guizzardi, S; Ruggeri, A

    2003-03-01

    The shape, surface composition and morphology of orthopaedic and endosseous dental titanium implants are key factors to achieve post-surgical and long-term mechanical stability and enhance implant osteointegration. In this study a comparison was made between 12 titanium screws, plasma-spray-coated with titanium powders (TPS), and 12 screws with an additional coating of fluorohydroxyapatite (FHA-Ti). Screws were implanted in the femoral and tibial diaphyses of two mongrel sheep and removed with peri-implant tissues 12 weeks after surgery. The vibrational spectroscopic, ultrastructural and morphological analyses showed good osteointegration for both types of implants in host cortical bone. The portion of the FHA-Ti implants in contact with the medullary canal showed a wider area of newly formed peri-implant bone than that of the TPS implants. Morphological and EDAX analyses demonstrated the presence of small titanium debris in the bone medullary spaces near the TPS surface, presumably due to the friction between the host bone and the implant during insertion. Few traces of titanium were detected around FHA-Ti implants, even if smaller FHA debris were present. The present findings suggest that the FHA coating may act as a barrier against the detachment of titanium debris stored in the medullary spaces near the implant surface.

  20. Scleral Buckling for Rhegmatogenous Retinal Detachment Associated with Pars Planitis

    PubMed Central

    Ahn, Jae Kyoun

    2016-01-01

    Purpose. To evaluate the surgical outcome of scleral buckling (SB) in rhegmatogenous retinal detachment (RRD) patients associated with pars planitis. Methods. Retrospective review of RRD patients (32 eyes of pars planitis RRD and 180 eyes of primary RRD) who underwent SB. We compared primary and final anatomical success rates and visual outcomes between two groups. Results. Primary and final anatomical success were achieved in 25 (78.1%) and 31 (96.8%) eyes in the pars planitis RRD group and in 167 eyes (92.7%) and 176 eyes (97.7%) in primary RRD group, respectively. Both groups showed significant visual improvement (p < 0.001) and there were no signi