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Sample records for drosophila discs large

  1. Imaging cell competition in Drosophila imaginal discs.

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    Ohsawa, Shizue; Sugimura, Kaoru; Takino, Kyoko; Igaki, Tatsushi

    2012-01-01

    Cell competition is a process in which cells with higher fitness ("winners") survive and proliferate at the expense of less fit neighbors ("losers"). It has been suggested that cell competition is involved in a variety of biological processes such as organ size control, tissue homeostasis, cancer progression, and the maintenance of stem cell population. By advent of a genetic mosaic technique, which enables to generate fluorescently marked somatic clones in Drosophila imaginal discs, recent studies have presented some aspects of molecular mechanisms underlying cell competition. Now, with a live-imaging technique using ex vivo-cultured imaginal discs, we can dissect the spatiotemporal nature of competitive cell behaviors within multicellular communities. Here, we describe procedures and tips for live imaging of cell competition in Drosophila imaginal discs. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. Dishevelled binds the Discs large 'Hook' domain to activate GukHolder-dependent spindle positioning in Drosophila.

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    Joshua D Garcia

    Full Text Available Communication between cortical cell polarity cues and the mitotic spindle ensures proper orientation of cell divisions within complex tissues. Defects in mitotic spindle positioning have been linked to various developmental disorders and have recently emerged as a potential contributor to tumorigenesis. Despite the importance of this process to human health, the molecular mechanisms that regulate spindle orientation are not fully understood. Moreover, it remains unclear how diverse cortical polarity complexes might cooperate to influence spindle positioning. We and others have demonstrated spindle orientation roles for Dishevelled (Dsh, a key regulator of planar cell polarity, and Discs large (Dlg, a conserved apico-basal cell polarity regulator, effects which were previously thought to operate within distinct molecular pathways. Here we identify a novel direct interaction between the Dsh-PDZ domain and the alternatively spliced "I3-insert" of the Dlg-Hook domain, thus establishing a potential convergent Dsh/Dlg pathway. Furthermore, we identify a Dlg sequence motif necessary for the Dsh interaction that shares homology to the site of Dsh binding in the Frizzled receptor. Expression of Dsh enhanced Dlg-mediated spindle positioning similar to deletion of the Hook domain. This Dsh-mediated activation was dependent on the Dlg-binding partner, GukHolder (GukH. These results suggest that Dsh binding may regulate core interdomain conformational dynamics previously described for Dlg. Together, our results identify Dlg as an effector of Dsh signaling and demonstrate a Dsh-mediated mechanism for the activation of Dlg/GukH-dependent spindle positioning. Cooperation between these two evolutionarily-conserved cell polarity pathways could have important implications to both the development and maintenance of tissue homeostasis in animals.

  3. Olfactory receptor signaling is regulated by the post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) scaffold multi-PDZ domain protein 1.

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    Dooley, Ruth

    2009-12-01

    The unique ability of mammals to detect and discriminate between thousands of different odorant molecules is governed by the diverse array of olfactory receptors expressed by olfactory sensory neurons in the nasal epithelium. Olfactory receptors consist of seven transmembrane domain G protein-coupled receptors and comprise the largest gene superfamily in the mammalian genome. We found that approximately 30% of olfactory receptors possess a classical post-synaptic density 95, Drosophila discs large, zona-occludens 1 (PDZ) domain binding motif in their C-termini. PDZ domains have been established as sites for protein-protein interaction and play a central role in organizing diverse cell signaling assemblies. In the present study, we show that multi-PDZ domain protein 1 (MUPP1) is expressed in the apical compartment of olfactory sensory neurons. Furthermore, on heterologous co-expression with olfactory sensory neurons, MUPP1 was shown to translocate to the plasma membrane. We found direct interaction of PDZ domains 1 + 2 of MUPP1 with the C-terminus of olfactory receptors in vitro. Moreover, the odorant-elicited calcium response of OR2AG1 showed a prolonged decay in MUPP1 small interfering RNA-treated cells. We have therefore elucidated the first building blocks of the putative \\'olfactosome\\

  4. Cooperative phosphoinositide and peptide binding by PSD-95/discs large/ZO-1 (PDZ) domain of polychaetoid, Drosophila zonulin.

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    Ivarsson, Ylva; Wawrzyniak, Anna Maria; Wuytens, Gunther; Kosloff, Mickey; Vermeiren, Elke; Raport, Marie; Zimmermann, Pascale

    2011-12-30

    PDZ domains are well known protein-protein interaction modules that, as part of multidomain proteins, assemble molecular complexes. Some PDZ domains have been reported to interact with membrane lipids, in particular phosphatidylinositol phosphates, but few studies have been aimed at elucidating the prevalence or the molecular details of such interactions. We screened 46 Drosophila PDZ domains for phosphoinositide-dependent cellular localization and discovered that the second PDZ domain of polychaetoid (Pyd PDZ2) interacts with phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P(2)) at the plasma membrane. Surface plasmon resonance binding experiments with recombinant protein established that Pyd PDZ2 interacts with phosphatidylinositol phosphates with apparent affinities in the micromolar range. Electrostatic interactions involving an extended positively charged surface of Pyd PDZ2 are crucial for the PtdIns(4,5)P(2)-dependent membrane interactions as shown by a combination of three-dimensional modeling, mutagenesis, binding, and localization studies. In vivo localization studies further suggested that both lipid and peptide binding contribute to membrane localization. We identified the transmembrane protein Crumbs as a Pyd PDZ2 ligand and probed the relation between peptide and PtdIns(4,5)P(2) binding. Contrary to the prevalent view on PDZ/peptide/lipid binding, we did not find competition between peptide and lipid ligands. Instead, preloading the protein with the 10-mer Crb3 peptide increased the apparent affinity of Pyd PDZ2 for PtdIns(4,5)P(2) 6-fold. Our results suggest that membrane localization of Pyd PDZ2 may be driven by a combination of peptide and PtdIns(4,5)P(2) binding, which raises the intriguing possibility that the domain may coordinate protein- and phospholipid-mediated signals.

  5. Dynamic interpretation of hedgehog signaling in the Drosophila wing disc.

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    Marcos Nahmad

    2009-09-01

    Full Text Available Morphogens are classically defined as molecules that control patterning by acting at a distance to regulate gene expression in a concentration-dependent manner. In the Drosophila wing imaginal disc, secreted Hedgehog (Hh forms an extracellular gradient that organizes patterning along the anterior-posterior axis and specifies at least three different domains of gene expression. Although the prevailing view is that Hh functions in the Drosophila wing disc as a classical morphogen, a direct correspondence between the borders of these patterns and Hh concentration thresholds has not been demonstrated. Here, we provide evidence that the interpretation of Hh signaling depends on the history of exposure to Hh and propose that a single concentration threshold is sufficient to support multiple outputs. Using mathematical modeling, we predict that at steady state, only two domains can be defined in response to Hh, suggesting that the boundaries of two or more gene expression patterns cannot be specified by a static Hh gradient. Computer simulations suggest that a spatial "overshoot" of the Hh gradient occurs, i.e., a transient state in which the Hh profile is expanded compared to the Hh steady-state gradient. Through a temporal examination of Hh target gene expression, we observe that the patterns initially expand anteriorly and then refine, providing in vivo evidence for the overshoot. The Hh gene network architecture suggests this overshoot results from the Hh-dependent up-regulation of the receptor, Patched (Ptc. In fact, when the network structure was altered such that the ptc gene is no longer up-regulated in response to Hh-signaling activation, we found that the patterns of gene expression, which have distinct borders in wild-type discs, now overlap. Our results support a model in which Hh gradient dynamics, resulting from Ptc up-regulation, play an instructional role in the establishment of patterns of gene expression.

  6. A Survey of 6,300 Genomic Fragments for cis-Regulatory Activity in the Imaginal Discs of Drosophila melanogaster

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    Aurélie Jory

    2012-10-01

    Full Text Available Over 6,000 fragments from the genome of Drosophila melanogaster were analyzed for their ability to drive expression of GAL4 reporter genes in the third-instar larval imaginal discs. About 1,200 reporter genes drove expression in the eye, antenna, leg, wing, haltere, or genital imaginal discs. The patterns ranged from large regions to individual cells. About 75% of the active fragments drove expression in multiple discs; 20% were expressed in ventral, but not dorsal, discs (legs, genital, and antenna, whereas ∼23% were expressed in dorsal but not ventral discs (wing, haltere, and eye. Several patterns, for example, within the leg chordotonal organ, appeared a surprisingly large number of times. Unbiased searches for DNA sequence motifs suggest candidate transcription factors that may regulate enhancers with shared activities. Together, these expression patterns provide a valuable resource to the community and offer a broad overview of how transcriptional regulatory information is distributed in the Drosophila genome.

  7. winged eye Induces Transdetermination of Drosophila Imaginal Disc by Acting in Concert with a Histone Methyltransferase, Su(var)3-9

    OpenAIRE

    Keita Masuko; Naoyuki Fuse; Kanae Komaba; Tomonori Katsuyama; Rumi Nakajima; Hirofumi Furuhashi; Shoichiro Kurata

    2018-01-01

    Summary: Drosophila imaginal disc cells exhibit a remarkable ability to convert cell fates in response to various perturbations, a phenomenon called transdetermination (TD). We previously identified winged eye (wge) as a factor that induces eye-to-wing TD upon overexpression in eye imaginal discs, but the molecular mechanisms underlying TD have remained largely unclear. Here, we found that wge induces various histone modifications and enhances the methylation of Lys9 on histone H3 (H3K9), a f...

  8. Excessive Myosin Activity in Mbs Mutants Causes Photoreceptor Movement Out of the Drosophila Eye Disc Epithelium

    OpenAIRE

    Lee, Arnold; Treisman, Jessica E.

    2004-01-01

    Neuronal cells must extend a motile growth cone while maintaining the cell body in its original position. In migrating cells, myosin contraction provides the driving force that pulls the rear of the cell toward the leading edge. We have characterized the function of myosin light chain phosphatase, which down-regulates myosin activity, in Drosophila photoreceptor neurons. Mutations in the gene encoding the myosin binding subunit of this enzyme cause photoreceptors to drop out of the eye disc e...

  9. winged eye Induces Transdetermination of Drosophila Imaginal Disc by Acting in Concert with a Histone Methyltransferase, Su(var3-9

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    Keita Masuko

    2018-01-01

    Full Text Available Summary: Drosophila imaginal disc cells exhibit a remarkable ability to convert cell fates in response to various perturbations, a phenomenon called transdetermination (TD. We previously identified winged eye (wge as a factor that induces eye-to-wing TD upon overexpression in eye imaginal discs, but the molecular mechanisms underlying TD have remained largely unclear. Here, we found that wge induces various histone modifications and enhances the methylation of Lys9 on histone H3 (H3K9, a feature of heterochromatin. A histone methyltransferase, Su(var3-9, is required for wge-mediated H3K9 methylation and eye-to-wing TD. Su(var3-9 is also required for classical wound-induced TD but not for normal development, suggesting its involvement in several types of imaginal disc TDs. Transcriptome analysis revealed that wge represses eye identity genes independently of Su(var3-9 and activates TD-related genes by acting together with Su(var3-9. These findings provide new insights into diverse types of chromatin regulation at progressive steps of cell-fate conversions. : Drosophila imaginal discs switch disc identity by a process known as transdetermination. Masuko et al. demonstrate that expression of the winged eye gene induces transdetermination through histone modifications such as H3K9-methylation. winged eye regulates expression of transdetermination-related genes via a histone methyltransferase, Su(var3-9. Keywords: Drosophila, imaginal disc, transdetermination, heterochromatin, cell fate, winged eye, reprogramming, Su(var3-9

  10. A Model of the Spatio-temporal Dynamics of Drosophila Eye Disc Development.

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    Fried, Patrick; Sánchez-Aragón, Máximo; Aguilar-Hidalgo, Daniel; Lehtinen, Birgitta; Casares, Fernando; Iber, Dagmar

    2016-09-01

    Patterning and growth are linked during early development and have to be tightly controlled to result in a functional tissue or organ. During the development of the Drosophila eye, this linkage is particularly clear: the growth of the eye primordium mainly results from proliferating cells ahead of the morphogenetic furrow (MF), a moving signaling wave that sweeps across the tissue from the posterior to the anterior side, that induces proliferating cells anterior to it to differentiate and become cell cycle quiescent in its wake. Therefore, final eye disc size depends on the proliferation rate of undifferentiated cells and on the speed with which the MF sweeps across the eye disc. We developed a spatio-temporal model of the growing eye disc based on the regulatory interactions controlled by the signals Decapentaplegic (Dpp), Hedgehog (Hh) and the transcription factor Homothorax (Hth) and explored how the signaling patterns affect the movement of the MF and impact on eye disc growth. We used published and new quantitative data to parameterize the model. In particular, two crucial parameter values, the degradation rate of Hth and the diffusion coefficient of Hh, were measured. The model is able to reproduce the linear movement of the MF and the termination of growth of the primordium. We further show that the model can explain several mutant phenotypes, but fails to reproduce the previously observed scaling of the Dpp gradient in the anterior compartment.

  11. A Model of the Spatio-temporal Dynamics of Drosophila Eye Disc Development.

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    Patrick Fried

    2016-09-01

    Full Text Available Patterning and growth are linked during early development and have to be tightly controlled to result in a functional tissue or organ. During the development of the Drosophila eye, this linkage is particularly clear: the growth of the eye primordium mainly results from proliferating cells ahead of the morphogenetic furrow (MF, a moving signaling wave that sweeps across the tissue from the posterior to the anterior side, that induces proliferating cells anterior to it to differentiate and become cell cycle quiescent in its wake. Therefore, final eye disc size depends on the proliferation rate of undifferentiated cells and on the speed with which the MF sweeps across the eye disc. We developed a spatio-temporal model of the growing eye disc based on the regulatory interactions controlled by the signals Decapentaplegic (Dpp, Hedgehog (Hh and the transcription factor Homothorax (Hth and explored how the signaling patterns affect the movement of the MF and impact on eye disc growth. We used published and new quantitative data to parameterize the model. In particular, two crucial parameter values, the degradation rate of Hth and the diffusion coefficient of Hh, were measured. The model is able to reproduce the linear movement of the MF and the termination of growth of the primordium. We further show that the model can explain several mutant phenotypes, but fails to reproduce the previously observed scaling of the Dpp gradient in the anterior compartment.

  12. Drosophila wing imaginal discs respond to mechanical injury via slow InsP3R-mediated intercellular calcium waves

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    Restrepo, Simon; Basler, Konrad

    2016-08-01

    Calcium signalling is a highly versatile cellular communication system that modulates basic functions such as cell contractility, essential steps of animal development such as fertilization and higher-order processes such as memory. We probed the function of calcium signalling in Drosophila wing imaginal discs through a combination of ex vivo and in vivo imaging and genetic analysis. Here we discover that wing discs display slow, long-range intercellular calcium waves (ICWs) when mechanically stressed in vivo or cultured ex vivo. These slow imaginal disc intercellular calcium waves (SIDICs) are mediated by the inositol-3-phosphate receptor, the endoplasmic reticulum (ER) calcium pump SERCA and the key gap junction component Inx2. The knockdown of genes required for SIDIC formation and propagation negatively affects wing disc recovery after mechanical injury. Our results reveal a role for ICWs in wing disc homoeostasis and highlight the utility of the wing disc as a model for calcium signalling studies.

  13. Cell proliferation control by Notch signalling during imaginal discs development in Drosophila

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    Carlos Estella

    2015-02-01

    Full Text Available The Notch signalling pathway is evolutionary conserved and participates in numerous developmental processes, including the control of cell proliferation. However, Notch signalling can promote or restrain cell division depending on the developmental context, as has been observed in human cancer where Notch can function as a tumor suppressor or an oncogene. Thus, the outcome of Notch signalling can be influenced by the cross-talk between Notch and other signalling pathways. The use of model organisms such as Drosophila has been proven to be very valuable to understand the developmental role of the Notch pathway in different tissues and its relationship with other signalling pathways during cell proliferation control. Here we review recent studies in Drosophila that shed light in the developmental control of cell proliferation by the Notch pathway in different contexts such as the eye, wing and leg imaginal discs. We also discuss the autonomous and non-autonomous effects of the Notch pathway on cell proliferation and its interactions with different signalling pathways.

  14. Large scale dynamics of protoplanetary discs

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    Béthune, William

    2017-08-01

    Planets form in the gaseous and dusty disks orbiting young stars. These protoplanetary disks are dispersed in a few million years, being accreted onto the central star or evaporated into the interstellar medium. To explain the observed accretion rates, it is commonly assumed that matter is transported through the disk by turbulence, although the mechanism sustaining turbulence is uncertain. On the other side, irradiation by the central star could heat up the disk surface and trigger a photoevaporative wind, but thermal effects cannot account for the observed acceleration and collimation of the wind into a narrow jet perpendicular to the disk plane. Both issues can be solved if the disk is sensitive to magnetic fields. Weak fields lead to the magnetorotational instability, whose outcome is a state of sustained turbulence. Strong fields can slow down the disk, causing it to accrete while launching a collimated wind. However, the coupling between the disk and the neutral gas is done via electric charges, each of which is outnumbered by several billion neutral molecules. The imperfect coupling between the magnetic field and the neutral gas is described in terms of "non-ideal" effects, introducing new dynamical behaviors. This thesis is devoted to the transport processes happening inside weakly ionized and weakly magnetized accretion disks; the role of microphysical effects on the large-scale dynamics of the disk is of primary importance. As a first step, I exclude the wind and examine the impact of non-ideal effects on the turbulent properties near the disk midplane. I show that the flow can spontaneously organize itself if the ionization fraction is low enough; in this case, accretion is halted and the disk exhibits axisymmetric structures, with possible consequences on planetary formation. As a second step, I study the launching of disk winds via a global model of stratified disk embedded in a warm atmosphere. This model is the first to compute non-ideal effects from

  15. High-resolution two-dimensional gel analysis of proteins in wing imaginal discs: A data base of Drosophila

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    Santaren, J.F.; Garcia-Bellido, A.

    1990-01-01

    An improved method of high-resolution two-dimensional gel electrophoresis has been used to study the patterns of protein synthesis in wing imaginal discs of late instar larvae of Drosophila melanogaster. A small number of discs were radiolabeled with a mixture of 14 C-labeled amino acids or with [ 35 S]methionine and the pattern of labeled proteins was analyzed. One thousand and twenty-five polypeptides (787 acidic (IEF) and 238 basic (NEPHGE)) from wing discs of several wild-type strains have so far been separated and cataloged. All these polypeptides have been numbered and presented in a reference map for further studies. When comparing patterns of label we have found small quantitative differences in rate of synthesis between individuals of the same strain, not due to sexual differences, and very few quantitative and qualitative differences between groups of individuals of different strains

  16. Integrins Regulate Apical Constriction via Microtubule Stabilization in the Drosophila Eye Disc Epithelium

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    Vilaiwan M. Fernandes

    2014-12-01

    Full Text Available During morphogenesis, extracellular signals trigger actomyosin contractility in subpopulations of cells to coordinate changes in cell shape. To illuminate the link between signaling-mediated tissue patterning and cytoskeletal remodeling, we study the progression of the morphogenetic furrow (MF, the wave of apical constriction that traverses the Drosophila eye imaginal disc preceding photoreceptor neurogenesis. Apical constriction depends on actomyosin contractility downstream of the Hedgehog (Hh and bone morphogenetic protein (BMP pathways. We identify a role for integrin adhesion receptors in MF progression. We show that Hh and BMP regulate integrin expression, the loss of which disrupts apical constriction and slows furrow progression; conversely, elevated integrins accelerate furrow progression. We present evidence that integrins regulate MF progression by promoting microtubule stabilization, since reducing microtubule stability rescues integrin-mediated furrow acceleration. Thus, integrins act as a genetic link between tissue-level signaling events and morphological change at the cellular level, leading to morphogenesis and neurogenesis in the eye.

  17. Relative autonomy of manifestation of welt mutation in imaginal discs of Drosophila

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    Vikulova, V.K.

    1988-01-01

    Autonomy of manifestation of the temperature-sensitive lethal welt mutation was investigated during transplantation of imaginal discs of mutant larvae into normal recipients and in large clones of cells homozygous for welt induced by γ-irradiation in a dose of 1000 rd in y; fj wt/M(2)S7 T(1;2)sc s 2 heterozygotes. Three temperature regimes were used: 17 degree C, at which the welt mutation is not manifested; 29 degree C, at which it is manifested better; and 25 degree C. It was established that the welt mutation operates autonomously, but in restricted regions of imaginal discs. The possibility is discussed of nonautonomous manifestation of the mutation with direct contact of wt/wt cells with heteroxygous wt/+ tissue

  18. winged eye Induces Transdetermination of Drosophila Imaginal Disc by Acting in Concert with a Histone Methyltransferase, Su(var)3-9.

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    Masuko, Keita; Fuse, Naoyuki; Komaba, Kanae; Katsuyama, Tomonori; Nakajima, Rumi; Furuhashi, Hirofumi; Kurata, Shoichiro

    2018-01-02

    Drosophila imaginal disc cells exhibit a remarkable ability to convert cell fates in response to various perturbations, a phenomenon called transdetermination (TD). We previously identified winged eye (wge) as a factor that induces eye-to-wing TD upon overexpression in eye imaginal discs, but the molecular mechanisms underlying TD have remained largely unclear. Here, we found that wge induces various histone modifications and enhances the methylation of Lys9 on histone H3 (H3K9), a feature of heterochromatin. A histone methyltransferase, Su(var)3-9, is required for wge-mediated H3K9 methylation and eye-to-wing TD. Su(var)3-9 is also required for classical wound-induced TD but not for normal development, suggesting its involvement in several types of imaginal disc TDs. Transcriptome analysis revealed that wge represses eye identity genes independently of Su(var)3-9 and activates TD-related genes by acting together with Su(var)3-9. These findings provide new insights into diverse types of chromatin regulation at progressive steps of cell-fate conversions. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  19. Safe physiotherapy interventions in large cervical disc herniations.

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    Keramat, Keramat Ullah

    2012-01-01

    A 34-year-old woman was seen in a physiotherapy department with signs and symptoms of cervical radiculopathy. Loss of cervical lordosis and a large paracentral to intraforaminal disc prolapse (8 mm) at C5-C6 level was reported on MRI. She was taking diclofenac sodium, tramadol HCl, diazepam and pregabalin for the preceding 2 months and no significant improvement, except temporary relief, was reported. She was referred to physiotherapy while awaiting a surgical opinion from a neurosurgeon. In physiotherapy she was treated with mobilisation of the upper thoracic spine from C7 to T6 level. A cervical extension exercise was performed with prior voluntary extension of the thoracic spine and elevated shoulders. She was advised to continue the same at home. General posture advice was given. Signs and symptoms resolved within the following four sessions of treatment over 3 weeks. Surgical intervention was subsequently deemed unnecessary.

  20. Percutaneous endoscopic intra-annular subligamentous herniotomy for large central disc herniation: a technical case report.

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    Lee, Sang-Ho; Choi, Kyung-Chul; Baek, Oon Ki; Kim, Ho Jin; Yoo, Seung-Hwa

    2014-04-01

    Technical case report. To describe the novel technique of percutaneous endoscopic herniotomy using a unilateral intra-annular subligamentous approach for the treatment of large centrally herniated discs. Open discectomy for large central disc herniations may have poor long-term prognosis due to heavy loss of intervertebral disc tissue, segmental instability, and recurrence of pain. Six consecutive patients who presented with back and leg pain, and/or weakness due to a large central disc herniation were treated using percutaneous endoscopic herniotomy with a unilateral intra-annular subligamentous approach. The patients experienced relief of symptoms and intervertebral disc spaces were well maintained. The annular defects were noted to be in the process of healing and recovery. Percutaneous endoscopic unilateral intra-annular subligamentous herniotomy was an effective and affordable minimally invasive procedure for patients with large central disc herniations, allowing preservation of nonpathological intradiscal tissue through a concentric outer-layer annular approach.

  1. The effect of parental factors in children with large cup-to-disc ratios.

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    Hae-Young Lopilly Park

    Full Text Available To investigate large cup-to-disc ratios (CDR in children and to determine the relationship between parental CDR and clinical characteristics associated with glaucoma.Two hundred thirty six children aged 6 to 12 years with CDR ≥ 0.6 were enrolled in this study. Subjects were classified into two groups based on parental CDR: disc suspect children with disc suspect (CDR ≥0.6 parents and disc suspect children without disc suspect parents. Ocular variables were compared between the two groups.Of the 236 disc suspect children, 100 (42.4% had at least one disc suspect parent. Intraocular pressure (IOP was higher in disc suspect children with disc suspect parents (16.52±2.66 mmHg than in disc suspect children without disc suspect parents (14.38±2.30 mmHg, p = 0.023. In the group with disc suspect parents, vertical CDR significantly correlated with IOP (R = -0.325, p = 0.001, average retinal nerve fiber layer (RNFL thickness (R = -0.319, p = 0.001, rim area (R = -0.740, p = 0.001, and cup volume (R = 0.499, p = 0.001. However, spherical equivalent (R = 0.333, p = 0.001, AL (R = -0.223, p = 0.009, and disc area (R = 0.325, p = 0.001 significantly correlated with vertical CDR in disc suspect children without disc suspect parents, in contrast to those with disc suspect parents. Larger vertical CDR was associated with the presence of disc suspect parents (p = 0.001, larger disc area (p = 0.001, thinner rim area (p = 0.001, larger average CDR (p = 0.001, and larger cup volume (p = 0.021.Family history of large CDR was a significant factor associated with large vertical CDR in children. In children with disc suspect parents, there were significant correlations between IOP and average RNFL thickness and vertical CDR.

  2. The effect of parental factors in children with large cup-to-disc ratios.

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    Park, Hae-Young Lopilly; Ha, Min Ji; Shin, Sun Young

    2017-01-01

    To investigate large cup-to-disc ratios (CDR) in children and to determine the relationship between parental CDR and clinical characteristics associated with glaucoma. Two hundred thirty six children aged 6 to 12 years with CDR ≥ 0.6 were enrolled in this study. Subjects were classified into two groups based on parental CDR: disc suspect children with disc suspect (CDR ≥0.6) parents and disc suspect children without disc suspect parents. Ocular variables were compared between the two groups. Of the 236 disc suspect children, 100 (42.4%) had at least one disc suspect parent. Intraocular pressure (IOP) was higher in disc suspect children with disc suspect parents (16.52±2.66 mmHg) than in disc suspect children without disc suspect parents (14.38±2.30 mmHg, p = 0.023). In the group with disc suspect parents, vertical CDR significantly correlated with IOP (R = -0.325, p = 0.001), average retinal nerve fiber layer (RNFL) thickness (R = -0.319, p = 0.001), rim area (R = -0.740, p = 0.001), and cup volume (R = 0.499, p = 0.001). However, spherical equivalent (R = 0.333, p = 0.001), AL (R = -0.223, p = 0.009), and disc area (R = 0.325, p = 0.001) significantly correlated with vertical CDR in disc suspect children without disc suspect parents, in contrast to those with disc suspect parents. Larger vertical CDR was associated with the presence of disc suspect parents (p = 0.001), larger disc area (p = 0.001), thinner rim area (p = 0.001), larger average CDR (p = 0.001), and larger cup volume (p = 0.021). Family history of large CDR was a significant factor associated with large vertical CDR in children. In children with disc suspect parents, there were significant correlations between IOP and average RNFL thickness and vertical CDR.

  3. Effects of X-rays on the proliferation dynamics of cells in the imaginal wing disc of Drosophila melanogaster

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    Haynie, J L; Bryant, P J [California Univ., Irvine (USA). Dept. of Developmental and Cell Biology; California Univ., Irvine (USA). Center for Pathobiology)

    1977-01-01

    The size distribution of clones marked by mitotic recombination induced by several different doses of X-rays applied to 72 h old Drosophila larvae is studied. The results indicate that irradiation significantly reduces the number of cells which undergo normal proliferation in the imaginal wing disc. It is estimated that 1000R reduces by 40-60% the number of cells capable of making a normal contribution to the development of the adult wing. Part of this reduction is due to severe curtailment in the proliferative ability of cells which nevertheless remain capable of adult differentiation: this effect is possibly due to radiation-induced aneuploidy. Cytological evidence suggests that immediate cell death also occurs as a result of radiation doses as low as 100R. The surviving cells are stimulated to undergo additional proliferation in response to the X-ray damage so that the result is the differentiation of a normal wing.

  4. Disruption of circumstellar discs by large-scale stellar magnetic fields

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    ud-Doula, Asif; Owocki, Stanley P.; Kee, Nathaniel Dylan

    2018-05-01

    Spectropolarimetric surveys reveal that 8-10% of OBA stars harbor large-scale magnetic fields, but thus far no such fields have been detected in any classical Be stars. Motivated by this, we present here MHD simulations for how a pre-existing Keplerian disc - like that inferred to form from decretion of material from rapidly rotating Be stars - can be disrupted by a rotation-aligned stellar dipole field. For characteristic stellar and disc parameters of a near-critically rotating B2e star, we find that a polar surface field strength of just 10 G can significantly disrupt the disc, while a field of 100 G, near the observational upper limit inferred for most Be stars, completely destroys the disc over just a few days. Our parameter study shows that the efficacy of this magnetic disruption of a disc scales with the characteristic plasma beta (defined as the ratio between thermal and magnetic pressure) in the disc, but is surprisingly insensitive to other variations, e.g. in stellar rotation speed, or the mass loss rate of the star's radiatively driven wind. The disc disruption seen here for even a modest field strength suggests that the presumed formation of such Be discs by decretion of material from the star would likely be strongly inhibited by such fields; this provides an attractive explanation for why no large-scale fields are detected from such Be stars.

  5. Reference interval for the disc-macula distance to disc diameter ratio in a large population of healthy Japanese adults

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    Sato, Ken-ichi

    2017-01-01

    Abstract This study presents the calculated reference interval for the disc-to-macula distance to disc diameter ratio (DM:DD) based on a large population of healthy Japanese adults. A total of 308 consecutive, healthy Japanese adults were examined in this prospective observational study. Eighteen subjects were also excluded because of poor quality of the fundus photograph of one or both eyes; 290 (161 men and 129 women) were included in this study. For each subject, a color fundus photograph of one eye, either the right or left, was randomly selected and used for analysis. On the photograph, the distances between the fovea and the nearest temporal margin of the optic disc (Dft), and the two kinds of disc diameters (D1 and D2), which bisected at right angles and one of which was directed to the fovea (D1), were measured. DM:DD was estimated using the formula: (2Dft + D1)/(D1 + D2). The mean ± standard deviation of DM:DD was 2.91 ± 0.49 for men and 2.96 ± 0.54 for women; there was no sex difference (P = .78, Mann–Whitney U test). Also, almost no relationship was found between DM:DD and age (ρ = −.12, P = .04, Spearman's rank correlation coefficient). The data did not fit a normal distribution (P < .001, Kolmogorov–Smirnov test). The estimated reference interval for DM:DD corresponding to the 2.5th and 97.5th percentiles was 2.12 to 4.18. Using a nonparametric approach, the reference interval for DM:DD of a large population of healthy Japanese adults was calculated to be 2.12 to 4.18, regardless of age or sex. PMID:28403107

  6. Status of prototype rupture disc testing in the large leak test rig

    International Nuclear Information System (INIS)

    Amos, J.C.

    1979-09-01

    The prototype CRBRP double membrane rupture disc assembly is being performance tested in conjunction with the LLTR Series II Large Leak Program. In May 1979, the double membrane disc assembly was inadvertently activated during sodium system pressure instrument calibration. This experience indicated that the rupture disc burst at essentially the design burst pressure when a gradually increasing state pressure was applied. The area of membrane opening was found to be about 25 to 30% of the cross-sectional area. In July 1979, the disc assembly was again tested (this time in a single membrane configuration) in conjunction with the first LLTR Series II Test A-1a (inert gas injection). Test data indicated that the disc burst in about 35 ms at essentially the design burst pressure with an opening of about 30% of the cross-sectional area. The pressure immediately downstream of the disc dropped below atmospheric pressure following the rupture tube event (releasing high pressure nitrogen into sodium) for about 1.5 seconds before increasing to a maximum of 30 psig. This behavior raises a question on the adequacy of a downstream pressure device for rapid sensing of disc rupture and initiating plant shutdown following a large SWR event. 14 figures

  7. Large-scale discovery of promoter motifs in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Thomas A Down

    2007-01-01

    Full Text Available A key step in understanding gene regulation is to identify the repertoire of transcription factor binding motifs (TFBMs that form the building blocks of promoters and other regulatory elements. Identifying these experimentally is very laborious, and the number of TFBMs discovered remains relatively small, especially when compared with the hundreds of transcription factor genes predicted in metazoan genomes. We have used a recently developed statistical motif discovery approach, NestedMICA, to detect candidate TFBMs from a large set of Drosophila melanogaster promoter regions. Of the 120 motifs inferred in our initial analysis, 25 were statistically significant matches to previously reported motifs, while 87 appeared to be novel. Analysis of sequence conservation and motif positioning suggested that the great majority of these discovered motifs are predictive of functional elements in the genome. Many motifs showed associations with specific patterns of gene expression in the D. melanogaster embryo, and we were able to obtain confident annotation of expression patterns for 25 of our motifs, including eight of the novel motifs. The motifs are available through Tiffin, a new database of DNA sequence motifs. We have discovered many new motifs that are overrepresented in D. melanogaster promoter regions, and offer several independent lines of evidence that these are novel TFBMs. Our motif dictionary provides a solid foundation for further investigation of regulatory elements in Drosophila, and demonstrates techniques that should be applicable in other species. We suggest that further improvements in computational motif discovery should narrow the gap between the set of known motifs and the total number of transcription factors in metazoan genomes.

  8. Comparison between cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs.

    Science.gov (United States)

    Gaitero, Luis; Nykamp, Stephanie; Daniel, Rob; Monteith, Gabrielle

    2013-01-01

    Cranial thoracic intervertebral disc herniations have been reported to be rare in dogs due to the presence of the intercapital ligament, however some studies have proposed they may not be uncommon in German Shepherd dogs. The purpose of this retrospective study was to compare cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs (control group). Medical records at the Ontario Veterinary College were searched for German Shepherd dogs and other large breed dogs that had magnetic resonance imaging studies including the T1-T9 region. For each dog and each disc space from T1-T9, three variables (compression, disc degeneration, and herniation) were recorded and graded based on review of sagittal T2-weighted images. Twenty-three German Shepherd dogs and 47 other large breed dogs met inclusion criteria. The German Shepherd dog group had higher scores than the control group for compression (P = 0.0099) and herniation (P dog group, intervertebral discs T2-T3 and T4-T5 had an increased risk for compression and T3-T4 had an increased risk for compression and herniation. Findings from this study indicated that German Shepherd dogs may be more likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniations. Imaging of the cranial thoracic spine, including T2-T3, is recommended for German Shepherd dogs with T3-L3 neurological signs. © 2012 Veterinary Radiology & Ultrasound.

  9. A retrospective study of epidural and intravenous steroids after percutaneous endoscopic lumbar discectomy for large lumbar disc herniation

    Directory of Open Access Journals (Sweden)

    Yang Zhang

    2017-02-01

    Conclusion: Patients who underwent PELD with epidural steroid administration for large lumbar disc herniation showed favorable curative effect compared with those who underwent PELD with intravenous steroid administration.

  10. Evidence for cell-replacement repair of X-ray-induced teratogenic damage in male genital imaginal discs of Drosophila melanogaster

    International Nuclear Information System (INIS)

    Fukunaga, Akihiro; Kondo, Sohei

    1985-01-01

    Male genital imaginal discs from old (late-third-instar) larvae of Drosophila that had been X-irradiated with appropriate doses developed into severely damaged adult genitalia when implanted into old larvae, but they developed into completely normal adult genitalia when transplanted into 2-day-younger larvae. Complete repair of X-ray-induced teratogenic damage in the genital discs on transplantation into young host larvae was similar in the wild-type and mei-9sup(a) strains. The results are discussed in relation to the hypothesis that repair of X-ray-induced teratogenic damage depends not on DNA repair but on replacement of damage-bearing primordial cells by healthy ones after suicidal elimination of the former. (Auth.)

  11. DISC1 conditioned GWAS for psychosis proneness in a large Finnish birth cohort.

    Directory of Open Access Journals (Sweden)

    Liisa Tomppo

    Full Text Available BACKGROUND: Genetic evidence implicates the DISC1 gene in the etiology of a number of mental illnesses. Previously, we have reported association between DISC1 and measures of psychosis proneness, the Revised Social Anhedonia Scale (RSAS and Revised Physical Anhedonia Scale (RPAS, in the Northern Finland Birth Cohort 1966 (NFBC66. As part of the studies of this Finnish birth cohort genome-wide association analysis has recently been performed. METHODOLOGY: In the present study, we re-analyzed the genome-wide association data with regard to these two measures of psychosis proneness, conditioning on our previous DISC1 observation. From the original NFBC66 sample (N = 12 058, 4 561 individuals provided phenotype and genotype data. No markers were significant at the genome-wide level. However, several genes with biological relevance to mental illnesses were highlighted through loci displaying suggestive evidence for association (≥3 SNP with P<10E-4. These included the protein coding genes, CXCL3, KIAA1128, LCT, MED13L, TMCO7, TTN, and the micro RNA MIR620. CONCLUSIONS: By conditioning a previous genome-wide association study on DISC1, we have been able to identify eight genes as associating to psychosis proneness. Further, these molecules predominantly link to the DISC1 pathway, strengthening the evidence for the role of this gene network in the etiology of mental illness. The use of quantitative measures of psychosis proneness in a large population cohort will make these findings, once verified; more generalized to a broad selection of disorders related to psychoses and psychosis proneness.

  12. Drosophila lipophorin receptors mediate the uptake of neutral lipids in oocytes and imaginal disc cells by an endocytosis-independent mechanism.

    Directory of Open Access Journals (Sweden)

    Esmeralda Parra-Peralbo

    2011-02-01

    Full Text Available Lipids are constantly shuttled through the body to redistribute energy and metabolites between sites of absorption, storage, and catabolism in a complex homeostatic equilibrium. In Drosophila, lipids are transported through the hemolymph in the form of lipoprotein particles, known as lipophorins. The mechanisms by which cells interact with circulating lipophorins and acquire their lipidic cargo are poorly understood. We have found that lipophorin receptor 1 and 2 (lpr1 and lpr2, two partially redundant genes belonging to the Low Density Lipoprotein Receptor (LDLR family, are essential for the efficient uptake and accumulation of neutral lipids by oocytes and cells of the imaginal discs. Females lacking the lpr2 gene lay eggs with low lipid content and have reduced fertility, revealing a central role for lpr2 in mediating Drosophila vitellogenesis. lpr1 and lpr2 are transcribed into multiple isoforms. Interestingly, only a subset of these isoforms containing a particular LDLR type A module mediate neutral lipid uptake. Expression of these isoforms induces the extracellular stabilization of lipophorins. Furthermore, our data indicate that endocytosis of the lipophorin receptors is not required to mediate the uptake of neutral lipids. These findings suggest a model where lipophorin receptors promote the extracellular lipolysis of lipophorins. This model is reminiscent of the lipolytic processing of triglyceride-rich lipoproteins that occurs at the mammalian capillary endothelium, suggesting an ancient role for LDLR-like proteins in this process.

  13. Large Steel Tank Fails and Rockets to Height of 30 meters - Rupture Disc Installed Incorrectly.

    Science.gov (United States)

    Hedlund, Frank H; Selig, Robert S; Kragh, Eva K

    2016-06-01

    At a brewery, the base plate-to-shell weld seam of a 90-m(3) vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

  14. Post-irradiation examinations and high-temperature tests on undoped large-grain UO{sub 2} discs

    Energy Technology Data Exchange (ETDEWEB)

    Noirot, J., E-mail: jean.noirot@cea.fr [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Pontillon, Y. [CEA, DEN, DEC, Cadarache, F-13108 St. Paul Lez Durance (France); Yagnik, S. [EPRI, P.O. Box 10412, Palo Alto, CA 94303-0813 (United States); Turnbull, J.A. [Independent Consultant (United Kingdom)

    2015-07-15

    Within the Nuclear Fuel Industry Research (NFIR) programme, several fuel variants –in the form of thin circular discs – were irradiated in the Halden Boiling Water Reactor (HBWR) at burn-ups up to ∼100 GWd/t{sub HM}. The design of the fuel assembly was similar to that used in other HBWR programmes: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature differences within each fuel disc. One such variant was made of large-grain UO{sub 2} discs (3D grain size = ∼45 μm) which were subjected to three burn-ups: 42, 72 and 96 GWd/t{sub HM}. Detailed characterizations of some of these irradiated large-grain UO{sub 2} discs were performed in the CEA Cadarache LECA-STAR hot laboratory. The techniques used included electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and secondary ion mass spectrometry (SIMS). Comparisons were then carried out with more standard grain size UO{sub 2} discs irradiated under the same conditions. Examination of the high burn-up large-grain UO{sub 2} discs revealed the limited formation of a high burn-up structure (HBS) when compared with the standard-grain UO{sub 2} discs at similar burn-up. High burn-up discs were submitted to temperature transients up to 1200 °C in the heating test device called Merarg at a relatively low temperature ramp rate (0.2 °C/s). In addition to the total gas release during these tests, the release peaks throughout the temperature ramp were monitored. Tests at 1600 °C were also conducted on the 42 GWd/t{sub HM} discs. The fuels were then characterized with the same microanalysis techniques as those used before the tests, to investigate the effects of these tests on the fuel’s microstructure and on the fission gas behaviour. This paper outlines the high resistance of this fuel to gas precipitation at high temperature and to HBS formation at high burn-up. It also shows the similarity of the positions, within the grains, where HBS forms

  15. Reference interval for the disc-macula distance to disc diameter ratio in a large population of healthy Japanese adults: A prospective, observational study.

    Science.gov (United States)

    Sato, Ken-Ichi

    2017-04-01

    This study presents the calculated reference interval for the disc-to-macula distance to disc diameter ratio (DM:DD) based on a large population of healthy Japanese adults.A total of 308 consecutive, healthy Japanese adults were examined in this prospective observational study. Eighteen subjects were also excluded because of poor quality of the fundus photograph of one or both eyes; 290 (161 men and 129 women) were included in this study. For each subject, a color fundus photograph of one eye, either the right or left, was randomly selected and used for analysis. On the photograph, the distances between the fovea and the nearest temporal margin of the optic disc (Dft), and the two kinds of disc diameters (D1 and D2), which bisected at right angles and one of which was directed to the fovea (D1), were measured. DM:DD was estimated using the formula: (2Dft + D1)/(D1 + D2).The mean ± standard deviation of DM:DD was 2.91 ± 0.49 for men and 2.96 ± 0.54 for women; there was no sex difference (P = .78, Mann-Whitney U test). Also, almost no relationship was found between DM:DD and age (ρ = -.12, P = .04, Spearman's rank correlation coefficient). The data did not fit a normal distribution (P < .001, Kolmogorov-Smirnov test). The estimated reference interval for DM:DD corresponding to the 2.5th and 97.5th percentiles was 2.12 to 4.18.Using a nonparametric approach, the reference interval for DM:DD of a large population of healthy Japanese adults was calculated to be 2.12 to 4.18, regardless of age or sex.

  16. Shadow of a Large Disc Casts New Light on the Formation of High Mass Stars

    Science.gov (United States)

    2004-05-01

    Massive Star Observed that Forms through a Rotating Accretion Disc Summary Based on a large observational effort with different telescopes and instruments, mostly from the European Southern Observatory (ESO), a team of European astronomers [1] has shown that in the M 17 nebula a high mass star [2] forms via accretion through a circumstellar disc, i.e. through the same channel as low-mass stars. To reach this conclusion, the astronomers used very sensitive infrared instruments to penetrate the south-western molecular cloud of M 17 so that faint emission from gas heated up by a cluster of massive stars, partly located behind the molecular cloud, could be detected through the dust. Against the background of this hot region a large opaque silhouette, which resembles a flared disc seen nearly edge-on, is found to be associated with an hour-glass shaped reflection nebula. This system complies perfectly with a newly forming high-mass star surrounded by a huge accretion disc and accompanied by an energetic bipolar mass outflow. The new observations corroborate recent theoretical calculations which claim that stars up to 40 times more massive than the Sun can be formed by the same processes that are active during the formation of stars of smaller masses. PR Photo 15a/04: Stellar cluster and star-forming region M 17 (also available without text inside photo) PR Photo 15b/04: Silhouette disc seen in M 17 PR Photo 15c/04: Rotation of the disc in M 17. PR Photo 15d/04: Bipolar reflection nebula and silhouette disc of a young, massive star in M 17 PR Photo 15e/04: Optical spectrum of the bipolar nebula. PR Video 03/04: Zooming in onto the disc. The M 17 region ESO PR Photo 15a/04 ESO PR Photo 15a/04 [Preview - JPEG: 400 x 497 pix - 271k] [Normal - JPEG: 800 x 958 pix - 604k] ESO PR Photo 15a1/04 ESO PR Photo 15a/04 (without text within photo) [Preview - JPEG: 400 x 480 pix - 275k] [Normal - JPEG: 800 x 959 pix - 634k] [High-Res - JPEG: 3000 x 3597 pix - 3.8M] [Full-Res - JPEG

  17. Drosophila imaginal disc growth factor 2 is a trophic factor involved in energy balance, detoxification, and innate immunity

    Czech Academy of Sciences Publication Activity Database

    Brož, Václav; Kučerová, Lucie; Rouhová, L.; Fleischmannová, Jana; Strnad, Hynek; Bryant, P. J.; Žurovec, Michal

    2017-01-01

    Roč. 7, FEB 23 (2017), č. článku 43273. ISSN 2045-2322 R&D Projects: GA ČR GA14-27816S; GA ČR GA14-07172S Institutional support: RVO:60077344 ; RVO:68378050 Keywords : Drosophila * innate immunity * IDGF2 Subject RIV: CE - Biochemistry; CE - Biochemistry (UMG-J) OBOR OECD: Biochemistry and molecular biology; Biochemistry and molecular biology (UMG-J) Impact factor: 4.259, year: 2016 http://www.nature.com/articles/srep43273

  18. Cap-n-Collar Promotes Tissue Regeneration by Regulating ROS and JNK Signaling in the Drosophila melanogaster Wing Imaginal Disc.

    Science.gov (United States)

    Brock, Amanda R; Seto, Mabel; Smith-Bolton, Rachel K

    2017-07-01

    Regeneration is a complex process that requires an organism to recognize and repair tissue damage, as well as grow and pattern new tissue. Here, we describe a genetic screen to identify novel regulators of regeneration. We ablated the Drosophila melanogaster larval wing primordium by inducing apoptosis in a spatially and temporally controlled manner and allowed the tissue to regenerate and repattern. To identify genes that regulate regeneration, we carried out a dominant-modifier screen by assessing the amount and quality of regeneration in adult wings heterozygous for isogenic deficiencies. We have identified 31 regions on the right arm of the third chromosome that modify the regenerative response. Interestingly, we observed several distinct phenotypes: mutants that regenerated poorly, mutants that regenerated faster or better than wild-type, and mutants that regenerated imperfectly and had patterning defects. We mapped one deficiency region to cap-n-collar ( cnc ), the Drosophila Nrf2 ortholog, which is required for regeneration. Cnc regulates reactive oxygen species levels in the regenerating epithelium, and affects c-Jun N-terminal protein kinase (JNK) signaling, growth, debris localization, and pupariation timing. Here, we present the results of our screen and propose a model wherein Cnc regulates regeneration by maintaining an optimal level of reactive oxygen species to promote JNK signaling. Copyright © 2017 by the Genetics Society of America.

  19. The apical scaffold big bang binds to spectrins and regulates the growth of Drosophila melanogaster wing discs.

    Science.gov (United States)

    Forest, Elodie; Logeay, Rémi; Géminard, Charles; Kantar, Diala; Frayssinoux, Florence; Heron-Milhavet, Lisa; Djiane, Alexandre

    2018-03-05

    During development, cell numbers are tightly regulated, ensuring that tissues and organs reach their correct size and shape. Recent evidence has highlighted the intricate connections between the cytoskeleton and the regulation of the key growth control Hippo pathway. Looking for apical scaffolds regulating tissue growth, we describe that Drosophila melanogaster big bang (Bbg), a poorly characterized multi-PDZ scaffold, controls epithelial tissue growth without affecting epithelial polarity and architecture. bbg -mutant tissues are smaller, with fewer cells that are less apically constricted than normal. We show that Bbg binds to and colocalizes tightly with the β-heavy-Spectrin/Kst subunit at the apical cortex and promotes Yki activity, F-actin enrichment, and the phosphorylation of the myosin II regulatory light chain Spaghetti squash. We propose a model in which the spectrin cytoskeleton recruits Bbg to the cortex, where Bbg promotes actomyosin contractility to regulate epithelial tissue growth. © 2018 Forest et al.

  20. Large-scale assessment of olfactory preferences and learning in Drosophila melanogaster: behavioral and genetic components

    Directory of Open Access Journals (Sweden)

    Elisabetta Versace

    2015-09-01

    Full Text Available In the Evolve and Resequence method (E&R, experimental evolution and genomics are combined to investigate evolutionary dynamics and the genotype-phenotype link. As other genomic approaches, this methods requires many replicates with large population sizes, which imposes severe restrictions on the analysis of behavioral phenotypes. Aiming to use E&R for investigating the evolution of behavior in Drosophila, we have developed a simple and effective method to assess spontaneous olfactory preferences and learning in large samples of fruit flies using a T-maze. We tested this procedure on (a a large wild-caught population and (b 11 isofemale lines of Drosophila melanogaster. Compared to previous methods, this procedure reduces the environmental noise and allows for the analysis of large population samples. Consistent with previous results, we show that flies have a preference for orange vs. apple odor. With our procedure wild-derived flies exhibit olfactory learning in the absence of previous laboratory selection. Furthermore, we find genetic differences in the olfactory learning with relatively high heritability. We propose this large-scale method as an effective tool for E&R and genome-wide association studies on olfactory preferences and learning.

  1. Large Steel Tank Fails and Rockets to Height of 30 meters − Rupture Disc Installed Incorrectly

    OpenAIRE

    Hedlund, Frank H.; Selig, Robert S.; Kragh, Eva K.

    2016-01-01

    At a brewery, the base plate-to-shell weld seam of a 90-m3 vertical cylindrical steel tank failed catastrophically. The 4 ton tank “took off” like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at <50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Dir...

  2. The genus Drosophila is characterized by a large number of sibling ...

    Indian Academy of Sciences (India)

    User

    A species is a basic unit of biological classification and a taxonomic rank ..... practical importance in applied biology such as agricultural pest control as .... Cordeiro J. and Toni D. C. D. 2014 Chromosomal evolution in the Drosophila cardini.

  3. A large-scale, in vivo transcription factor screen defines bivalent chromatin as a key property of regulatory factors mediating Drosophila wing development.

    Science.gov (United States)

    Schertel, Claus; Albarca, Monica; Rockel-Bauer, Claudia; Kelley, Nicholas W; Bischof, Johannes; Hens, Korneel; van Nimwegen, Erik; Basler, Konrad; Deplancke, Bart

    2015-04-01

    Transcription factors (TFs) are key regulators of cell fate. The estimated 755 genes that encode DNA binding domain-containing proteins comprise ∼ 5% of all Drosophila genes. However, the majority has remained uncharacterized so far due to the lack of proper genetic tools. We generated 594 site-directed transgenic Drosophila lines that contain integrations of individual UAS-TF constructs to facilitate spatiotemporally controlled misexpression in vivo. All transgenes were expressed in the developing wing, and two-thirds induced specific phenotypic defects. In vivo knockdown of the same genes yielded a phenotype for 50%, with both methods indicating a great potential for misexpression to characterize novel functions in wing growth, patterning, and development. Thus, our UAS-TF library provides an important addition to the genetic toolbox of Drosophila research, enabling the identification of several novel wing development-related TFs. In parallel, we established the chromatin landscape of wing imaginal discs by ChIP-seq analyses of five chromatin marks and RNA Pol II. Subsequent clustering revealed six distinct chromatin states, with two clusters showing enrichment for both active and repressive marks. TFs that carry such "bivalent" chromatin are highly enriched for causing misexpression phenotypes in the wing, and analysis of existing expression data shows that these TFs tend to be differentially expressed across the wing disc. Thus, bivalently marked chromatin can be used as a marker for spatially regulated TFs that are functionally relevant in a developing tissue. © 2015 Schertel et al.; Published by Cold Spring Harbor Laboratory Press.

  4. Large-scale isolation and fractionation of organs of Drosophila melanogaster larvae.

    Science.gov (United States)

    Zweidler, A; Cohen, L H

    1971-10-01

    Methods for the mass isolation of diverse organs from small animals are described. They involve novel devices: a mechanical dissecting system, a centrifugal agitator for the separation of fibrillar from globular particles, and a settling chamber for the fractionation at unit gravity of particles with sedimentation velocities above the useful range for centrifugation. The application of these methods to the isolation of polytene and nonpolytene nuclei from Drosophila melanogaster larvae is described.

  5. 2D Bayesian automated tilted-ring fitting of disc galaxies in large H I galaxy surveys: 2DBAT

    Science.gov (United States)

    Oh, Se-Heon; Staveley-Smith, Lister; Spekkens, Kristine; Kamphuis, Peter; Koribalski, Bärbel S.

    2018-01-01

    We present a novel algorithm based on a Bayesian method for 2D tilted-ring analysis of disc galaxy velocity fields. Compared to the conventional algorithms based on a chi-squared minimization procedure, this new Bayesian-based algorithm suffers less from local minima of the model parameters even with highly multimodal posterior distributions. Moreover, the Bayesian analysis, implemented via Markov Chain Monte Carlo sampling, only requires broad ranges of posterior distributions of the parameters, which makes the fitting procedure fully automated. This feature will be essential when performing kinematic analysis on the large number of resolved galaxies expected to be detected in neutral hydrogen (H I) surveys with the Square Kilometre Array and its pathfinders. The so-called 2D Bayesian Automated Tilted-ring fitter (2DBAT) implements Bayesian fits of 2D tilted-ring models in order to derive rotation curves of galaxies. We explore 2DBAT performance on (a) artificial H I data cubes built based on representative rotation curves of intermediate-mass and massive spiral galaxies, and (b) Australia Telescope Compact Array H I data from the Local Volume H I Survey. We find that 2DBAT works best for well-resolved galaxies with intermediate inclinations (20° < i < 70°), complementing 3D techniques better suited to modelling inclined galaxies.

  6. Instability of warped discs

    Science.gov (United States)

    Doǧan, S.; Nixon, C. J.; King, A. R.; Pringle, J. E.

    2018-05-01

    Accretion discs are generally warped. If a warp in a disc is too large, the disc can `break' apart into two or more distinct planes, with only tenuous connections between them. Further, if an initially planar disc is subject to a strong differential precession, then it can be torn apart into discrete annuli that precess effectively independently. In previous investigations, torque-balance formulae have been used to predict where and when the disc breaks into distinct parts. In this work, focusing on discs with Keplerian rotation and where the shearing motions driving the radial communication of the warp are damped locally by turbulence (the `diffusive' regime), we investigate the stability of warped discs to determine the precise criterion for an isolated warped disc to break. We find and solve the dispersion relation, which, in general, yields three roots. We provide a comprehensive analysis of this viscous-warp instability and the emergent growth rates and their dependence on disc parameters. The physics of the instability can be understood as a combination of (1) a term that would generally encapsulate the classical Lightman-Eardley instability in planar discs (given by ∂(νΣ)/∂Σ < 0) but is here modified by the warp to include ∂(ν1|ψ|)/∂|ψ| < 0, and (2) a similar condition acting on the diffusion of the warp amplitude given in simplified form by ∂(ν2|ψ|)/∂|ψ| < 0. We discuss our findings in the context of discs with an imposed precession, and comment on the implications for different astrophysical systems.

  7. Double rupture disc experience

    International Nuclear Information System (INIS)

    1979-01-01

    Result of these observations, comparisons and evaluations can be summarized in the following list of concerns regarding the use of double rupture discs coupled to the liquid space of a steam generator that is subjected to a large leak sodium water reaction event. Single rupture disc show delayed collapse characteristics in LLTR Series I and double disc assemblies are presumed to be more complex with additional delay before opening to give pressure relief. Delayed failure increases pressures in the IHTS and must be adequately covered by design requirements. With CRBR design, the first disc may fail only partially reducing the loading on the second disc with the result that relief performance may not meet requirements

  8. Artificial Disc Replacement

    Science.gov (United States)

    ... Spondylolisthesis BLOG FIND A SPECIALIST Treatments Artificial Disc Replacement (ADR) Patient Education Committee Jamie Baisden The disc ... Disc An artificial disc (also called a disc replacement, disc prosthesis or spine arthroplasty device) is a ...

  9. big bang gene modulates gut immune tolerance in Drosophila.

    Science.gov (United States)

    Bonnay, François; Cohen-Berros, Eva; Hoffmann, Martine; Kim, Sabrina Y; Boulianne, Gabrielle L; Hoffmann, Jules A; Matt, Nicolas; Reichhart, Jean-Marc

    2013-02-19

    Chronic inflammation of the intestine is detrimental to mammals. Similarly, constant activation of the immune response in the gut by the endogenous flora is suspected to be harmful to Drosophila. Therefore, the innate immune response in the gut of Drosophila melanogaster is tightly balanced to simultaneously prevent infections by pathogenic microorganisms and tolerate the endogenous flora. Here we describe the role of the big bang (bbg) gene, encoding multiple membrane-associated PDZ (PSD-95, Discs-large, ZO-1) domain-containing protein isoforms, in the modulation of the gut immune response. We show that in the adult Drosophila midgut, BBG is present at the level of the septate junctions, on the apical side of the enterocytes. In the absence of BBG, these junctions become loose, enabling the intestinal flora to trigger a constitutive activation of the anterior midgut immune response. This chronic epithelial inflammation leads to a reduced lifespan of bbg mutant flies. Clearing the commensal flora by antibiotics prevents the abnormal activation of the gut immune response and restores a normal lifespan. We now provide genetic evidence that Drosophila septate junctions are part of the gut immune barrier, a function that is evolutionarily conserved in mammals. Collectively, our data suggest that septate junctions are required to maintain the subtle balance between immune tolerance and immune response in the Drosophila gut, which represents a powerful model to study inflammatory bowel diseases.

  10. Tracing Planets in Circumstellar Discs

    Directory of Open Access Journals (Sweden)

    Uribe Ana L.

    2013-04-01

    Full Text Available Planets are assumed to form in circumstellar discs around young stellar objects. The additional gravitational potential of a planet perturbs the disc and leads to characteristic structures, i.e. spiral waves and gaps, in the disc density profile. We perform a large-scale parameter study on the observability of these planet-induced structures in circumstellar discs in the (submm wavelength range for the Atacama Large (SubMillimeter Array (ALMA. On the basis of hydrodynamical and magneto-hydrodynamical simulations of star-disc-planet models we calculate the disc temperature structure and (submm images of these systems. These are used to derive simulated ALMA maps. Because appropriate objects are frequent in the Taurus-Auriga region, we focus on a distance of 140 pc and a declination of ≈ 20°. The explored range of star-disc-planet configurations consists of six hydrodynamical simulations (including magnetic fields and different planet masses, nine disc sizes with outer radii ranging from 9 AU to 225 AU, 15 total disc masses in the range between 2.67·10-7 M⊙ and 4.10·10-2 M⊙, six different central stars and two different grain size distributions, resulting in 10 000 disc models. At almost all scales and in particular down to a scale of a few AU, ALMA is able to trace disc structures induced by planet-disc interaction or the influence of magnetic fields in the wavelength range between 0.4...2.0 mm. In most cases, the optimum angular resolution is limited by the sensitivity of ALMA. However, within the range of typical masses of protoplane tary discs (0.1 M⊙...0.001 M⊙ the disc mass has a minor impact on the observability. At the distance of 140 pc it is possible to resolve discs down to 2.67·10-6 M⊙ and trace gaps in discs with 2.67·10-4 M⊙ with a signal-to-noise ratio greater than three. In general, it is more likely to trace planet-induced gaps in magneto-hydrodynamical disc models, because gaps are wider in the presence of

  11. MRI T2* mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model

    NARCIS (Netherlands)

    Detiger, Suzanne E. L.; Holewijn, Roderick M.; Hoogendoorn, Roel J. W.; van Royen, Barend J.; Helder, Marco N.; Berger, Ferco H.; Kuijer, Joost P. A.; Smit, Theo H.

    2015-01-01

    To evaluate intervertebral disc (IVD) degeneration and treatments, an objective diagnostic tool is needed. Recently, T2* relaxation time mapping was proposed as a technique to assess early IVD degeneration, yet the correlation with biochemical content and histological features has not been

  12. MRI T2* mapping correlates with biochemistry and histology in intervertebral disc degeneration in a large animal model

    NARCIS (Netherlands)

    Detiger, S.E.L.; Holewijn, R.M.; Hoogendoorn, R.J.W.; van Royen, B.J.; Helder, M.N.; Berger, F.H.; Kuijer, J.P.A.; Smit, T.H.

    2015-01-01

    Purpose: To evaluate intervertebral disc (IVD) degeneration and treatments, an objective diagnostic tool is needed. Recently, T2* relaxation time mapping was proposed as a technique to assess early IVD degeneration, yet the correlation with biochemical content and histological features has not been

  13. In vivo relevance of intercellular calcium signaling in Drosophila wing development

    OpenAIRE

    Brodskiy, Pavel; Brito-Robinson, Teresa; Levis, Megan; Narciso, Cody; Jangula, Jamison; Huizar, Francisco; Wu, Qinfeng; Zartman, Jeremiah

    2017-01-01

    Recently, organ-scale intercellular Ca2+ transients (ICTs) were reported in the Drosophila wing disc. However, the functional in vivo significance of ICTs remains largely unknown. Here we demonstrate the in vivo relevance of intercellular Ca2+ signaling and its impact on wing development. We report that Ca2+ signaling in vivo decreases as wing discs mature. Ca2+ signaling ex vivo responds to fly extract in a dose-dependent manner. This suggests ICTs occur in vivo due to chemical stimulus that...

  14. Large clusters of co-expressed genes in the Drosophila genome.

    Science.gov (United States)

    Boutanaev, Alexander M; Kalmykova, Alla I; Shevelyov, Yuri Y; Nurminsky, Dmitry I

    2002-12-12

    Clustering of co-expressed, non-homologous genes on chromosomes implies their co-regulation. In lower eukaryotes, co-expressed genes are often found in pairs. Clustering of genes that share aspects of transcriptional regulation has also been reported in higher eukaryotes. To advance our understanding of the mode of coordinated gene regulation in multicellular organisms, we performed a genome-wide analysis of the chromosomal distribution of co-expressed genes in Drosophila. We identified a total of 1,661 testes-specific genes, one-third of which are clustered on chromosomes. The number of clusters of three or more genes is much higher than expected by chance. We observed a similar trend for genes upregulated in the embryo and in the adult head, although the expression pattern of individual genes cannot be predicted on the basis of chromosomal position alone. Our data suggest that the prevalent mechanism of transcriptional co-regulation in higher eukaryotes operates with extensive chromatin domains that comprise multiple genes.

  15. A microsatellite linkage map for Drosophila montana shows large variation in recombination rates, and a courtship song trait maps to an area of low recombination.

    Science.gov (United States)

    Schäfer, M A; Mazzi, D; Klappert, K; Kauranen, H; Vieira, J; Hoikkala, A; Ritchie, M G; Schlötterer, C

    2010-03-01

    Current advances in genetic analysis are opening up our knowledge of the genetics of species differences, but challenges remain, particularly for out-bred natural populations. We constructed a microsatellite-based linkage map for two out-bred lines of Drosophila montana derived from divergent populations by taking advantage of the Drosophila virilis genome and available cytological maps of both species. Although the placement of markers was quite consistent with cytological predictions, the map indicated large heterogeneity in recombination rates along chromosomes. We also performed a quantitative trait locus (QTL) analysis on a courtship song character (carrier frequency), which differs between populations and is subject to strong sexual selection. Linkage mapping yielded two significant QTLs, which explained 3% and 14% of the variation in carrier frequency, respectively. Interestingly, as in other recent studies of traits which can influence speciation, the strongest QTL mapped to a genomic region partly covered by an inversion polymorphism.

  16. Influence of crossed fields in structures combining large grain, bulk (RE)BCO superconductors and soft ferromagnetic discs

    International Nuclear Information System (INIS)

    Philippe, M P; Fagnard, J F; Wéra, L; Vanderheyden, B; Vanderbemden, P; Morita, M; Nariki, S; Teshima, H; Caps, H

    2016-01-01

    Bulk (RE)BCO superconductors are able to trap record magnetic fields and can be used as powerful permanent magnets in various engineering applications such as rotating machines and magnetic bearings. When such superconducting (SC) “trapped field magnets” are combined to a ferromagnetic (FM) disc, the total magnetic moment is increased with respect to that of the superconductor alone. In the present work, we study experimentally the magnetic behaviour of such hybrid FM/SC structures when they are subjected to cycles of applied field that are orthogonal to their permanent magnetization, i.e. a “crossed-field” configuration. Experimental results show that the usual “crossed-field demagnetization” caused by the cycles of transverse field is strongly reduced in the presence of the ferromagnet. (paper)

  17. Thermochemical modelling of brown dwarf discs

    NARCIS (Netherlands)

    Greenwood, A. J.; Kamp, I.; Waters, L. B. F. M.; Woitke, P.; Thi, W.-F.; Rab, Ch.; Aresu, G.; Spaans, M.

    The physical properties of brown dwarf discs, in terms of their shapes and sizes, are still largely unexplored by observations. ALMA has by far the best capabilities to observe these discs in sub-mm CO lines and dust continuum, while also spatially resolving some discs. To what extent brown dwarf

  18. The Galactic stellar disc

    International Nuclear Information System (INIS)

    Feltzing, S; Bensby, T

    2008-01-01

    The study of the Milky Way stellar discs in the context of galaxy formation is discussed. In particular, we explore the properties of the Milky Way disc using a new sample of about 550 dwarf stars for which we have recently obtained elemental abundances and ages based on high-resolution spectroscopy. For all the stars we also have full kinematic information as well as information about their stellar orbits. We confirm results from previous studies that the thin and the thick discs have distinct abundance patterns. But we also explore a larger range of orbital parameters than what has been possible in our previous studies. Several new results are presented. We find that stars that reach high above the Galactic plane and have eccentric orbits show remarkably tight abundance trends. This implies that these stars formed out of well-mixed gas that had been homogenized over large volumes. We find some evidence that suggest that the event that most likely caused the heating of this stellar population happened a few billion years ago. Through a simple, kinematic exploration of stars with super-solar [Fe/H], we show that the solar neighbourhood contains metal-rich, high velocity stars that are very likely associated with the thick disc. Additionally, the HR1614 moving group and the Hercules and Arcturus stellar streams are discussed and it is concluded that, probably, a large fraction of the groups and streams so far identified in the disc are the result of evolution and interactions within the stellar disc rather than being dissolved stellar clusters or engulfed dwarf galaxies.

  19. Disc defect classification for optical disc drives

    NARCIS (Netherlands)

    Helvoirt, van J.; Leenknegt, G.A.L.; Steinbuch, M.; Goossens, H.J.

    2005-01-01

    Optical disc drives are subject to various disturbances and faults. A special type of fault is the so-called disc defect. In this paper we present an approach for disc defect classification. It is based on hierarchical clustering of measured signals that are affected by disc defects. The

  20. Simulations of an Offshore Wind Farm Using Large-Eddy Simulation and a Torque-Controlled Actuator Disc Model

    Science.gov (United States)

    Creech, Angus; Früh, Wolf-Gerrit; Maguire, A. Eoghan

    2015-05-01

    We present here a computational fluid dynamics (CFD) simulation of Lillgrund offshore wind farm, which is located in the Øresund Strait between Sweden and Denmark. The simulation combines a dynamic representation of wind turbines embedded within a large-eddy simulation CFD solver and uses hr-adaptive meshing to increase or decrease mesh resolution where required. This allows the resolution of both large-scale flow structures around the wind farm, and the local flow conditions at individual turbines; consequently, the response of each turbine to local conditions can be modelled, as well as the resulting evolution of the turbine wakes. This paper provides a detailed description of the turbine model which simulates the interaction between the wind, the turbine rotors, and the turbine generators by calculating the forces on the rotor, the body forces on the air, and instantaneous power output. This model was used to investigate a selection of key wind speeds and directions, investigating cases where a row of turbines would be fully aligned with the wind or at specific angles to the wind. Results shown here include presentations of the spin-up of turbines, the observation of eddies moving through the turbine array, meandering turbine wakes, and an extensive wind farm wake several kilometres in length. The key measurement available for cross-validation with operational wind farm data is the power output from the individual turbines, where the effect of unsteady turbine wakes on the performance of downstream turbines was a main point of interest. The results from the simulations were compared to the performance measurements from the real wind farm to provide a firm quantitative validation of this methodology. Having achieved good agreement between the model results and actual wind farm measurements, the potential of the methodology to provide a tool for further investigations of engineering and atmospheric science problems is outlined.

  1. Archival-grade optical disc design and international standards

    Science.gov (United States)

    Fujii, Toru; Kojyo, Shinichi; Endo, Akihisa; Kodaira, Takuo; Mori, Fumi; Shimizu, Atsuo

    2015-09-01

    Optical discs currently on the market exhibit large variations in life span among discs, making them unsuitable for certain business applications. To assess and potentially mitigate this problem, we performed accelerated degradation testing under standard ISO conditions, determined the probable disc failure mechanisms, and identified the essential criteria necessary for a stable disc composition. With these criteria as necessary conditions, we analyzed the physical and chemical changes that occur in the disc components, on the basis of which we determined technological measures to reduce these degradation processes. By applying these measures to disc fabrication, we were able to develop highly stable optical discs.

  2. A Simulation Model of Focus and Radial Servos in Compact Disc Players with Disc Surface Defects

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2004-01-01

    Compact Disc players have been on the market in more than two decades.As a consequence most of the control servo problems have been solved. A large remaining problem to solve is the handling of Compact Discs with severe surface defects like scratches and fingerprints. This paper introduces a method...... for making the design of controllers handling surface defects easier. A simulation model of Compact Disc players playing discs with surface defects is presented. The main novel element in the model is a model of the surface defects. That model is based on data from discs with surface defects. This model...

  3. Changes in localization of human discs large (hDlg) during keratinocyte differentiation is associated with expression of alternatively spliced hDlg variants

    International Nuclear Information System (INIS)

    Roberts, S.; Calautti, E.; Vanderweil, S.; Nguyen, H.O.; Foley, A.; Baden, H.P.; Viel, A.

    2007-01-01

    Alternative spliced variants of the human discs large (hDlg) tumour suppressor are characterized by combinations of insertions. Here, using insertions I2- and I3-specific antibodies, we show that I2 and I3 variants have distinct distributions in epidermal and cervical epithelia. In skin and cervix, I3 variants are found in the cytoplasm. Cytoplasmic localization of I3 variants decreases as cervical keratinocytes differentiate, concomitant with relocalization to the cell periphery. I2 variants are found at the cell periphery of differentiated epidermal and cervical keratinocytes. Nuclear localization of I2 variants was evident in both tissues, with concentration of nuclear I2 variants in basal and parabasal cervical keratinocytes. A prominent nuclear localization of hDlg in cells of hyperproliferative layers of psoriatic lesions, but not in mature differentiated keratinocytes, together with I2 redistribution in differentiating keratinocytes, suggests that nuclear hDlg functions may be pertinent to growth of undifferentiated cells. Supporting our findings in squamous tissues, a decrease of nuclear hDlg and an increase of membrane-bound and cytoplasmic hDlg upon calcium-induced keratinocyte differentiation were not concomitant processes. Furthermore, we confirm that the exit of I2 variants from the nucleus is linked to stimulation of epithelial differentiation. The dynamic redistribution of hDlg also correlated with a marked increase in the expression of I3 variants while the level of I2 variants showed only a moderate decrease. Because changes in the intracellular distribution of hDlg splice variants, and in their expression levels, correlate with changes in differentiation state we hypothesize that the different hDlg isoforms play distinct roles at various stages of epithelial differentiation

  4. Identification of synaptic targets of Drosophila pumilio.

    Directory of Open Access Journals (Sweden)

    Gengxin Chen

    2008-02-01

    Full Text Available Drosophila Pumilio (Pum protein is a translational regulator involved in embryonic patterning and germline development. Recent findings demonstrate that Pum also plays an important role in the nervous system, both at the neuromuscular junction (NMJ and in long-term memory formation. In neurons, Pum appears to play a role in homeostatic control of excitability via down regulation of para, a voltage gated sodium channel, and may more generally modulate local protein synthesis in neurons via translational repression of eIF-4E. Aside from these, the biologically relevant targets of Pum in the nervous system remain largely unknown. We hypothesized that Pum might play a role in regulating the local translation underlying synapse-specific modifications during memory formation. To identify relevant translational targets, we used an informatics approach to predict Pum targets among mRNAs whose products have synaptic localization. We then used both in vitro binding and two in vivo assays to functionally confirm the fidelity of this informatics screening method. We find that Pum strongly and specifically binds to RNA sequences in the 3'UTR of four of the predicted target genes, demonstrating the validity of our method. We then demonstrate that one of these predicted target sequences, in the 3'UTR of discs large (dlg1, the Drosophila PSD95 ortholog, can functionally substitute for a canonical NRE (Nanos response element in vivo in a heterologous functional assay. Finally, we show that the endogenous dlg1 mRNA can be regulated by Pumilio in a neuronal context, the adult mushroom bodies (MB, which is an anatomical site of memory storage.

  5. Proto-planetary disc evolution and dispersal

    Science.gov (United States)

    Rosotti, Giovanni Pietro

    2015-05-01

    Planets form from gas and dust discs in orbit around young stars. The timescale for planet formation is constrained by the lifetime of these discs. The properties of the formed planetary systems depend thus on the evolution and final dispersal of the discs, which is the main topic of this thesis. Observations reveal the existence of a class of discs called "transitional", which lack dust in their inner regions. They are thought to be the last stage before the complete disc dispersal, and hence they may provide the key to understanding the mechanisms behind disc evolution. X-ray photoevaporation and planet formation have been studied as possible physical mechanisms responsible for the final dispersal of discs. However up to now, these two phenomena have been studied separately, neglecting any possible feedback or interaction. In this thesis we have investigated what is the interplay between these two processes. We show that the presence of a giant planet in a photo-evaporating disc can significantly shorten its lifetime, by cutting the inner regions from the mass reservoir in the exterior of the disc. This mechanism produces transition discs that for a given mass accretion rate have larger holes than in models considering only X-ray photo-evaporation, constituting a possible route to the formation of accreting transition discs with large holes. These discs are found in observations and still constitute a puzzle for the theory. Inclusion of the phenomenon called "thermal sweeping", a violent instability that can destroy a whole disc in as little as 10 4 years, shows that the outer disc left can be very short-lived (depending on the X-ray luminosity of the star), possibly explaining why very few non accreting transition discs are observed. However the mechanism does not seem to be efficient enough to reconcile with observations. In this thesis we also show that X-ray photo-evaporation naturally explains the observed correlation between stellar masses and accretion

  6. The influence of large deletions on the mutation frequency induced by tritiated water and X-radiation in male Drosophila melanogaster post-meiotic germ cells

    International Nuclear Information System (INIS)

    Fossett, N.G.; Byrne, B.J.; Kelley, S.J.; Tucker, A.B.; Arbour-Reily, P.; Lee, W.R.

    1994-01-01

    Tritium beta radiation ( 3 H β-radiation) in the form of tritiated water was used to induce mutations at the alcohol dehydrogenase (Adh) locus in male Drosophila melanogaster post-meiotic germ cells. All 23 Adh null mutations were large deletions (>20 kb), determined by genetic complementation and Southern blot analyses. 27 Adh null mutations have been induced by 100-kVp X-rays and have been genetically and molecularly characterized. In contrast to 3 H β-radiation, 100-kVp X-rays induced a bimodal distribution of Adh null mutations, intragenic mutations, ≤250 bp, and large deletions, >100 kb. A statistically significant difference was observed between the frequency of large deletions (23/23 or 1.0) induced by 3 H β-radiation and the frequency of large deletions (19/27 or 0.7) induced by 100-kVp X-rays. However, a statistical difference was not observed between the size distribution of the large deletions induced by 3 H β-radiation and X-rays. The relative deletion frequency (RDF) induced by 3 H β-radiation and 100-kVp X-rays was (1.0/0.7=1.4). The relative biological effectiveness (RBE) of these two radiation sources was 1.4, determined from the ratio of the regression coefficients of the respective 3 H β-radiation and X-ray sex-linked recessive lethal (SLRL) dose-response data. The large difference in size between the two classes of X-ray-induced Adh null mutations and the increase in mutation frequency and deletion frequency for 3 H β-radiation with respect to X-rays may indicate that the relative deletion frequency (RDF) is the molecular biological basis for the increase in the RBE for radiation sources with a mean LET value ≤10 keV/μm

  7. The human adenovirus E4-ORF1 protein subverts discs large 1 to mediate membrane recruitment and dysregulation of phosphatidylinositol 3-kinase.

    Directory of Open Access Journals (Sweden)

    Kathleen Kong

    2014-05-01

    Full Text Available Adenoviruses infect epithelial cells lining mucous membranes to cause acute diseases in people. They are also utilized as vectors for vaccination and for gene and cancer therapy, as well as tools to discover mechanisms of cancer due to their tumorigenic potential in experimental animals. The adenovirus E4-ORF1 gene encodes an oncoprotein that promotes viral replication, cell survival, and transformation by activating phosphatidylinositol 3-kinase (PI3K. While the mechanism of activation is not understood, this function depends on a complex formed between E4-ORF1 and the membrane-associated cellular PDZ protein Discs Large 1 (Dlg1, a common viral target having both tumor suppressor and oncogenic functions. Here, we report that in human epithelial cells, E4-ORF1 interacts with the regulatory and catalytic subunits of PI3K and elevates their levels. Like PI3K activation, PI3K protein elevation by E4-ORF1 requires Dlg1. We further show that Dlg1, E4-ORF1, and PI3K form a ternary complex at the plasma membrane. At this site, Dlg1 also co-localizes with the activated PI3K effector protein Akt, indicating that the ternary complex mediates PI3K signaling. Signifying the functional importance of the ternary complex, the capacity of E4-ORF1 to induce soft agar growth and focus formation in cells is ablated either by a mutation that prevents E4-ORF1 binding to Dlg1 or by a PI3K inhibitor drug. These results demonstrate that E4-ORF1 interacts with Dlg1 and PI3K to assemble a ternary complex where E4-ORF1 hijacks the Dlg1 oncogenic function to relocate cytoplasmic PI3K to the membrane for constitutive activation. This novel mechanism of Dlg1 subversion by adenovirus to dysregulate PI3K could be used by other pathogenic viruses, such as human papillomavirus, human T-cell leukemia virus type 1, and influenza A virus, which also target Dlg1 and activate PI3K in cells.

  8. The Drosophila T-box transcription factor Midline functions within the Notch–Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc

    Science.gov (United States)

    Das, Sudeshna; Chen, Q. Brent; Saucier, Joseph D.; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M.

    2014-01-01

    We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch–Delta signaling pathway essential for specifying the fates of sensory organ precursor cells. This complements an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in diverse neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch–Delta signaling hierarchy and is essential for maintaining cell viability within by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. PMID:23962751

  9. The Drosophila T-box transcription factor Midline functions within the Notch-Delta signaling pathway to specify sensory organ precursor cell fates and regulates cell survival within the eye imaginal disc.

    Science.gov (United States)

    Das, Sudeshna; Chen, Q Brent; Saucier, Joseph D; Drescher, Brandon; Zong, Yan; Morgan, Sarah; Forstall, John; Meriwether, Andrew; Toranzo, Randy; Leal, Sandra M

    2013-01-01

    We report that the T-box transcription factor Midline (Mid), an evolutionary conserved homolog of the vertebrate Tbx20 protein, functions within the Notch-Delta signaling pathway essential for specifying the fates of sensory organ precursor (SOP) cells. These findings complement an established history of research showing that Mid regulates the cell-fate specification of diverse cell types within the developing heart, epidermis and central nervous system. Tbx20 has been detected in unique neuronal and epithelial cells of embryonic eye tissues in both mice and humans. However, the mechanisms by which either Mid or Tbx20 function to regulate cell-fate specification or other critical aspects of eye development including cell survival have not yet been elucidated. We have also gathered preliminary evidence suggesting that Mid may play an indirect, but vital role in selecting SOP cells within the third-instar larval eye disc by regulating the expression of the proneural gene atonal. During subsequent pupal stages, Mid specifies SOP cell fates as a member of the Notch-Delta signaling hierarchy and is essential for maintaining cell viability by inhibiting apoptotic pathways. We present several new hypotheses that seek to understand the role of Mid in regulating developmental processes downstream of the Notch receptor that are critical for specifying unique cell fates, patterning the adult eye and maintaining cellular homeostasis during eye disc morphogenesis. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  10. Radially truncated galactic discs

    NARCIS (Netherlands)

    Grijs, R. de; Kregel, M.; Wesson, K H

    2000-01-01

    Abstract: We present the first results of a systematic analysis of radially truncatedexponential discs for four galaxies of a sample of disc-dominated edge-onspiral galaxies. Edge-on galaxies are very useful for the study of truncatedgalactic discs, since we can follow their light distributions out

  11. Tolerance in Drosophila

    OpenAIRE

    Atkinson, Nigel S.

    2009-01-01

    The set of genes that underlie ethanol tolerance (inducible resistance) are likely to overlap with the set of genes responsible for ethanol addiction. Whereas addiction is difficult to recognize in simple model systems, behavioral tolerance is readily identifiable and can be induced in large populations of animals. Thus, tolerance lends itself to analysis in model systems with powerful genetics. Drosophila melanogaster has been used by a variety of laboratories for the identification of genes...

  12. Rupture disc

    International Nuclear Information System (INIS)

    Newton, R.G.

    1977-01-01

    The intermediate heat transport system for a sodium-cooled fast breeder reactor includes a device for rapidly draining the sodium therefrom should a sodium-water reaction occur within the system. This device includes a rupturable member in a drain line in the system and means for cutting a large opening therein and for positively removing the sheared-out portion from the opening cut in the rupturable member. According to the preferred embodiment of the invention the rupturable member includes a solid head seated in the end of the drain line having a rim extending peripherally therearound, the rim being clamped against the end of the drain line by a clamp ring having an interior shearing edge, the bottom of the rupturable member being convex and extending into the drain line. Means are provided to draw the rupturable member away from the drain line against the shearing edge to clear the drain line for outflow of sodium therethrough

  13. Drosophila type II neuroblast lineages keep Prospero levels low to generate large clones that contribute to the adult brain central complex

    Directory of Open Access Journals (Sweden)

    Drummond Michael L

    2010-10-01

    Full Text Available Abstract Tissue homeostasis depends on the ability of stem cells to properly regulate self-renewal versus differentiation. Drosophila neural stem cells (neuroblasts are a model system to study self-renewal and differentiation. Recent work has identified two types of larval neuroblasts that have different self-renewal/differentiation properties. Type I neuroblasts bud off a series of small basal daughter cells (ganglion mother cells that each generate two neurons. Type II neuroblasts bud off small basal daughter cells called intermediate progenitors (INPs, with each INP generating 6 to 12 neurons. Type I neuroblasts and INPs have nuclear Asense and cytoplasmic Prospero, whereas type II neuroblasts lack both these transcription factors. Here we test whether Prospero distinguishes type I/II neuroblast identity or proliferation profile, using several newly characterized Gal4 lines. We misexpress prospero using the 19H09-Gal4 line (expressed in type II neuroblasts but no adjacent type I neuroblasts or 9D11-Gal4 line (expressed in INPs but not type II neuroblasts. We find that differential prospero expression does not distinguish type I and type II neuroblast identities, but Prospero regulates proliferation in both type I and type II neuroblast lineages. In addition, we use 9D11 lineage tracing to show that type II lineages generate both small-field and large-field neurons within the adult central complex, a brain region required for locomotion, flight, and visual pattern memory.

  14. Minimum weight design of inhomogeneous rotating discs

    International Nuclear Information System (INIS)

    Jahed, Hamid; Farshi, Behrooz; Bidabadi, Jalal

    2005-01-01

    There are numerous applications for gas turbine discs in the aerospace industry such as in turbojet engines. These discs normally work under high temperatures while subjected to high angular velocities. Minimizing the weight of such items in aerospace applications results in benefits such as low dead weights and lower costs. High speed of rotation causes large centrifugal forces in a disc and simultaneous application of high temperatures reduces disc material strength. Thus, the latter effects tend to increase deformations of the disc under the applied loads. In order to obtain a reliable disc analysis and arrive at the corresponding correct stress distribution, solutions should consider changes in material properties due to the temperature field throughout the disc. To achieve this goal, an inhomogeneous disc model with variable thickness is considered. Using the variable material properties method, stresses are obtained for the disc under rotation and a steady temperature field. In this paper this is done by modelling the rotating disc as a series of rings of different but constant properties. The optimum disc profile is arrived at by sequentially proportioning the thicknesses of each ring to satisfy the stress requirements. This method vis-a-vis a mathematical programming procedure for optimization shows several advantages. Firstly, it is simple iterative proportioning in each design cycle not requiring involved mathematical operations. Secondly, due to its simplicity it alleviates the necessity of certain simplifications that are common in so-called rigorous mathematical procedures. The results obtained, compared to those published in the literature show agreement and superiority. A further advantage of the proposed method is the independence of the end results from the initially assumed point in the iterative design routine, unlike most methods published so far

  15. The rapid evolution of X-linked male-biased gene expression and the large-X effect in Drosophila yakuba, D. santomea, and their hybrids.

    Science.gov (United States)

    Llopart, Ana

    2012-12-01

    The X chromosome has a large effect on hybrid dysfunction, particularly on hybrid male sterility. Although the evidence for this so-called large-X effect is clear, its molecular causes are not yet fully understood. One possibility is that, under certain conditions, evolution proceeds faster in X-linked than in autosomal loci (i.e., faster-X effect) due to both natural selection and their hemizygosity in males, an effect that is expected to be greatest in genes with male-biased expression. Here, I study genome-wide variation in transcript abundance between Drosophila yakuba and D. santomea, within these species and in their hybrid males to evaluate both the faster-X and large-X effects at the level of expression. I find that in X-linked male-biased genes (MBGs) expression evolves faster than in their autosomal counterparts, an effect that is accompanied by a unique reduction in expression polymorphism. This suggests that Darwinian selection is driving expression differences between species, likely enhanced by the hemizygosity of the X chromosome in males. Despite the recent split of the two sister species under study, abundant changes in both cis- and trans-regulatory elements underlie expression divergence in the majority of the genes analyzed, with significant differences in allelic ratios of transcript abundance between the two reciprocal F(1) hybrid males. Cis-trans coevolution at molecular level, evolved shortly after populations become isolated, may therefore contribute to explain the breakdown of the regulation of gene expression in hybrid males. Additionally, the X chromosome plays a large role in this hybrid male misexpression, which affects not only MBG but also, to a lesser degree, nonsex-biased genes. Interestingly, hybrid male misexpression is concentrated mostly in autosomal genes, likely facilitated by the rapid evolution of sex-linked trans-acting factors. I suggest that the faster evolution of X-linked MBGs, at both protein and expression levels

  16. Superluminous accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M [Cambridge Univ. (UK). Inst. of Astronomy; Polska Akademia Nauk, Warsaw. Centrum Astronomiczne)

    1981-07-01

    Upper limits are computed for the total luminosities and collimation of radiation from thick, radiation supported accretion discs around black holes. Numerical results are obtained for the 'extreme' discs with rsub(out) = 10/sup 3/ GMsub(BH)/c/sup 2/, the angular momentum of the black hole being Jsub(BH) = 0.998 GMsub(BH)/c. The high luminosity (L approximately 8.5 Lsub(Edd)) and substantial collimation of radiation found for these discs indicate that such discs can explain both the high luminosities of quasars and similar objects and may produce some of the observed beams and jets.

  17. On the diversity and statistical properties of protostellar discs

    Science.gov (United States)

    Bate, Matthew R.

    2018-04-01

    We present results from the first population synthesis study of protostellar discs. We analyse the evolution and properties of a large sample of protostellar discs formed in a radiation hydrodynamical simulation of star cluster formation. Due to the chaotic nature of the star formation process, we find an enormous diversity of young protostellar discs, including misaligned discs, and discs whose orientations vary with time. Star-disc interactions truncate discs and produce multiple systems. Discs may be destroyed in dynamical encounters and/or through ram-pressure stripping, but reform by later gas accretion. We quantify the distributions of disc mass and radii for protostellar ages up to ≈105 yr. For low-mass protostars, disc masses tend to increase with both age and protostellar mass. Disc radii range from of order 10 to a few hundred au, grow in size on time-scales ≲ 104 yr, and are smaller around lower mass protostars. The radial surface density profiles of isolated protostellar discs are flatter than the minimum mass solar nebula model, typically scaling as Σ ∝ r-1. Disc to protostar mass ratios rarely exceed two, with a typical range of Md/M* = 0.1-1 to ages ≲ 104 yr and decreasing thereafter. We quantify the relative orientation angles of circumstellar discs and the orbit of bound pairs of protostars, finding a preference for alignment that strengths with decreasing separation. We also investigate how the orientations of the outer parts of discs differ from the protostellar and inner disc spins for isolated protostars and pairs.

  18. Disc operational system

    International Nuclear Information System (INIS)

    Veretenov, V.Yu.; Volkov, A.I.; Gurevich, M.I.; Kozik, V.S.; Pod'yachev, E.I.; Shapiro, M.L.

    1974-01-01

    A disc operational system is proposed, which is based on the file structure and designed for use in a BESM-6 computer with the software system comprising a dispatcher DD-73 and a monitor 'Dubna'. The main distinguishing feature of the disc operational system is the decentralization of the file system. Each disc package is an independent file unaffected by the state of the other disc packages. The use of several disc packages is allowed. The above feature of the disc operational system makes it possible to simplify the language of communication with the system, to give the user the opportunity of controlling the file quite independently, and to simplify the maintenance of the discs by the computer personnel. One and the same disc can be simultaneously addressed by all problems in the processor (both mathematical and service). A single file, however, may be used in the recording mode by only one problem. The description presented is the instruction for users. It also describes special possibilities open to the system programmers [ru

  19. Intratracheal Seal Disc

    DEFF Research Database (Denmark)

    Christiansen, Karen J; Moeslund, Niels; Lauridsen, Henrik

    2017-01-01

    . The device consisted of an intratracheal silicone seal disc fixated by a cord through the stoma to an external part. At day 14, computed tomography (CT) was performed before the device was extracted. With the pulling of a cord, the disc unraveled into a thin thread and was extracted through the stoma. At day...

  20. Optic disc oedema

    DEFF Research Database (Denmark)

    Nielsen, Marianne Kromann; Hamann, Steffen

    2014-01-01

    Optic disc oedema describes the nonspecific, localized swelling of the optic nerve head regardless of aetiology. Therefore, differentiating among the various aetiologies depends on a thorough history and knowledge of the clinical characteristics of the underlying conditions. Papilloedema strictly...... refers to optic disc oedema as a consequence of elevated intracranial pressure. It is usually a bilateral condition and visual function is preserved until late. Optic disc oedema caused by an anterior optic neuropathy is usually unilateral and accompanied by the loss of visual function....

  1. The wings of Bombyx mori develop from larval discs exhibiting an ...

    Indian Academy of Sciences (India)

    Unknown

    presumptive wing blade domains unlike in Drosophila, where it is confined to the hinge and the wing pouch. ... events are different and the wing discs behave like presumptive wing buds .... emerge with the fore- and the hind-wings (figure 1e, j) on ... phosis (compare c with d, and h with i) during the larval to pupal transition.

  2. Herniated Cervical Disc

    Science.gov (United States)

    ... are sometimes prescribed for more severe arm and neck pain because of their very powerful anti-inflammatory effect. ... caused by a herniated cervical disc. However, some neck pain may persist. Most patients respond well to discectomy; ...

  3. CELLULAR LOCALIZATION AND EXPRESSION OF pygo DURING DROSOPHILA DEVELOPMENT

    Institute of Scientific and Technical Information of China (English)

    LINXin-da; LINXin-hua; CHENGJia-an

    2003-01-01

    Wg/Wnt signaling is a key signaling pathway in Drosophila. Many genes involved in Wingless(wg) signal transduction pathway downstream of Wg, or it'' s vertebrate Wg homologue Wnt, have been identified.Transduction of the Wg signal downstream of Wg is mediated by nuclear TCF/LEF-1, through association with Ar-madillo (Arm)/β-catenin. Pygopus (pygo) is a new identified component in this pathway . Cellular localization experiment showed that pygo was expressed specifically in the nucleus. The expression profile of pygo in embryos was examined using in situ hybridization. Although pygo expressed ubiquitously in the embryos, it expressed at relatively high level in pre-blastoderm embryos which indicate a high degree of maternally provided message, fol-lowed by a low level of ubiquitous zygotic expression. This continues into larval tissues (including wing disc, eye disc and leg disc), where pygo appears to be expressed at low level. Comparison of pygo expression levels, in the wing disc, eye disc and leg disc, showed pygo expression level in the wing disc pouch and leg disc were rela-tive higher.

  4. Evidence for accreted component in the Galactic discs

    Science.gov (United States)

    Xing, Q. F.; Zhao, G.

    2018-06-01

    We analyse the distribution of [Mg/Fe] abundance in the Galactic discs with F- and G-type dwarf stars selected from the Large Sky Area Multi-Object Fibre Spectroscopic Telescope (LAMOST) archive. The sample stars are assigned into different stellar populations by using kinematic criteria. Our analysis reveals the chemical inhomogeneities in the Galactic thick disc. A few of metal-poor stars in the thick disc exhibit relatively low [Mg/Fe] abundance in respect to the standard thick-disc sample. The orbital eccentricities and maximum Galactocentric radii of low-α metal-poor stars are apparently greater than that of high-α thick-disc stars. The orbital parameters and chemical components of low-α stars in the thick disc suggest that they may have been formed in regions with low star formation rate that were located at large distances from the Galactic centre, such as infalling dwarf spheroidal galaxies.

  5. Normal modes of Bardeen discs

    International Nuclear Information System (INIS)

    Verdaguer, E.

    1983-01-01

    The short wavelength normal modes of self-gravitating rotating polytropic discs in the Bardeen approximation are studied. The discs' oscillations can be seen in terms of two types of modes: the p-modes whose driving forces are pressure forces and the r-modes driven by Coriolis forces. As a consequence of differential rotation coupling between the two takes place and some mixed modes appear, their properties can be studied under the assumption of weak coupling and it is seen that they avoid the crossing of the p- and r-modes. The short wavelength analysis provides a basis for the classification of the modes, which can be made by using the properties of their phase diagrams. The classification is applied to the large wavelength modes of differentially rotating discs with strong coupling and to a uniformly rotating sequence with no coupling, which have been calculated in previous papers. Many of the physical properties and qualitative features of these modes are revealed by the analysis. (author)

  6. SUMOylation in Drosophila Development

    Directory of Open Access Journals (Sweden)

    Albert J. Courey

    2012-07-01

    Full Text Available Small ubiquitin-related modifier (SUMO, an ~90 amino acid ubiquitin-like protein, is highly conserved throughout the eukaryotic domain. Like ubiquitin, SUMO is covalently attached to lysine side chains in a large number of target proteins. In contrast to ubiquitin, SUMO does not have a direct role in targeting proteins for proteasomal degradation. However, like ubiquitin, SUMO does modulate protein function in a variety of other ways. This includes effects on protein conformation, subcellular localization, and protein–protein interactions. Significant insight into the in vivo role of SUMOylation has been provided by studies in Drosophila that combine genetic manipulation, proteomic, and biochemical analysis. Such studies have revealed that the SUMO conjugation pathway regulates a wide variety of critical cellular and developmental processes, including chromatin/chromosome function, eggshell patterning, embryonic pattern formation, metamorphosis, larval and pupal development, neurogenesis, development of the innate immune system, and apoptosis. This review discusses our current understanding of the diverse roles for SUMO in Drosophila development.

  7. Apparent quasar disc sizes in the "bird's nest" paradigm

    Science.gov (United States)

    Abolmasov, P.

    2017-04-01

    Context. Quasar microlensing effects make it possible to measure the accretion disc sizes around distant supermassive black holes that are still well beyond the spatial resolution of contemporary instrumentation. The sizes measured with this technique appear inconsistent with the standard accretion disc model. Not only are the measured accretion disc sizes larger, but their dependence on wavelength is in most cases completely different from the predictions of the standard model. Aims: We suggest that these discrepancies may arise not from non-standard accretion disc structure or systematic errors, as it was proposed before, but rather from scattering and reprocession of the radiation of the disc. In particular, the matter falling from the gaseous torus and presumably feeding the accretion disc may at certain distances become ionized and produce an extended halo that is free from colour gradients. Methods: A simple analytical model is proposed assuming that a geometrically thick translucent inflow acts as a scattering mirror changing the apparent spatial properties of the disc. This inflow may be also identified with the broad line region or its inner parts. Results: Such a model is able to explain the basic properties of the apparent disc sizes, primarily their large values and their shallow dependence on wavelength. The only condition required is to scatter a significant portion of the luminosity of the disc. This can easily be fulfilled if the scattering inflow has a large geometrical thickness and clumpy structure.

  8. Spontaneous and complete regression of a thoracic disc herniation

    International Nuclear Information System (INIS)

    Coevoet, V.; Benoudiba, F.; Doyon, D.; Lignieres, C.; Said, G.

    1997-01-01

    Spontaneous regression of disc herniation is well known but the mechanism is not clear. Some hypotheses have been made. We present here a large thoracic disc herniation diagnosed by MRI which completely regressed one year after a medical treatment with complete amendment of symptoms. (authors)

  9. Isolated Optic Disc Tuberculosis

    Science.gov (United States)

    Mansour, Ahmad M.; Tabbara, Khalid F.; Tabbarah, Zuhair

    2015-01-01

    We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation. PMID:26483675

  10. Isolated Optic Disc Tuberculosis

    Directory of Open Access Journals (Sweden)

    Ahmad M. Mansour

    2015-09-01

    Full Text Available We present a healthy male subject who developed progressive visual loss in the left eye initially diagnosed as optic neuritis. Upon suspicion of infectious etiology, testing was positive for tuberculosis. There were no signs or symptoms of active systemic tuberculosis infection. The patient responded swiftly to antimycobacterial therapy with return of vision and resolution of disc swelling. Positive purified protein derivative skin test, negative chest radiograph, negative systemic workup, negative workup for other causes of unilateral optic neuritis and quick response to mycobacterial therapy reaffirm the entity of isolated optic disc tuberculosis similar to isolated choroidal tuberculosis without systemic manifestation.

  11. Characterization of big bang, a novel gene encoding for PDZ domain-containing proteins that are dynamically expressed throughout Drosophila development.

    Science.gov (United States)

    Kim, Sabrina Y; Renihan, Maia K; Boulianne, Gabrielle L

    2006-06-01

    PDZ (PSD-95, Discs-large, ZO-1) domain proteins often function as scaffolding proteins and have been shown to play important roles in diverse cellular processes such as the establishment and maintenance of cell polarity, and signal transduction. Here, we report the identification and cloning of a novel Drosophila melanogaster gene that is predicted to produce several different PDZ domain-containing proteins through alternative promoter usage and alternative splicing. This gene, that we have named big bang (bbg), was first identified as C96-GAL4, a GAL4 enhancer trap line that was generated in our lab. To further characterize bbg, its expression pattern was examined in ovaries, embryos, and late third instar larvae using UAS reporter gene constructs, in situ hybridization, or immunocytochemistry. In addition, the expression of alternatively spliced transcripts was examined in more detail using in situ hybridization. We find that during embryogenesis bbg is predominantly expressed in the developing gut, but it is also expressed in external sensory organs found in the epidermis. In the late third instar larva, bbg is expressed along the presumptive wing margin in the wing disc, broadly in the eye disc, and in other imaginal discs as well as in the brain. The expression patterns observed are dynamic and specific during development, suggesting that like other genes that encode for several different PDZ domain protein isoforms, bbg likely plays important roles in multiple developmental processes.

  12. Only marginal alignment of disc galaxies

    Science.gov (United States)

    Andrae, René; Jahnke, Knud

    2011-12-01

    Testing theories of angular-momentum acquisition of rotationally supported disc galaxies is the key to understanding the formation of this type of galaxies. The tidal-torque theory aims to explain this acquisition process in a cosmological framework and predicts positive autocorrelations of angular-momentum orientation and spiral-arm handedness, i.e. alignment of disc galaxies, on short distance scales of 1 Mpc h-1. This disc alignment can also cause systematic effects in weak-lensing measurements. Previous observations claimed discovering these correlations but are overly optimistic in the reported level of statistical significance of the detections. Errors in redshift, ellipticity and morphological classifications were not taken into account, although they have a significant impact. We explain how to rigorously propagate all the important errors through the estimation process. Analysing disc galaxies in the Sloan Digital Sky Survey (SDSS) data base, we find that positive autocorrelations of spiral-arm handedness and angular-momentum orientations on distance scales of 1 Mpc h-1 are plausible but not statistically significant. Current data appear not good enough to constrain parameters of theory. This result agrees with a simple hypothesis test in the Local Group, where we also find no evidence for disc alignment. Moreover, we demonstrate that ellipticity estimates based on second moments are strongly biased by galactic bulges even for Scd galaxies, thereby corrupting correlation estimates and overestimating the impact of disc alignment on weak-lensing studies. Finally, we discuss the potential of future sky surveys. We argue that photometric redshifts have too large errors, i.e. PanSTARRS and LSST cannot be used. Conversely, the EUCLID project will not cover the relevant redshift regime. We also discuss the potentials and problems of front-edge classifications of galaxy discs in order to improve the autocorrelation estimates of angular-momentum orientation.

  13. Metabolome analysis of Drosophila melanogaster during embryogenesis.

    Science.gov (United States)

    An, Phan Nguyen Thuy; Yamaguchi, Masamitsu; Bamba, Takeshi; Fukusaki, Eiichiro

    2014-01-01

    The Drosophila melanogaster embryo has been widely utilized as a model for genetics and developmental biology due to its small size, short generation time, and large brood size. Information on embryonic metabolism during developmental progression is important for further understanding the mechanisms of Drosophila embryogenesis. Therefore, the aim of this study is to assess the changes in embryos' metabolome that occur at different stages of the Drosophila embryonic development. Time course samples of Drosophila embryos were subjected to GC/MS-based metabolome analysis for profiling of low molecular weight hydrophilic metabolites, including sugars, amino acids, and organic acids. The results showed that the metabolic profiles of Drosophila embryo varied during the course of development and there was a strong correlation between the metabolome and different embryonic stages. Using the metabolome information, we were able to establish a prediction model for developmental stages of embryos starting from their high-resolution quantitative metabolite composition. Among the important metabolites revealed from our model, we suggest that different amino acids appear to play distinct roles in different developmental stages and an appropriate balance in trehalose-glucose ratio is crucial to supply the carbohydrate source for the development of Drosophila embryo.

  14. A Drosophila wing spot test

    International Nuclear Information System (INIS)

    Ayaki, Toshikazu; Yoshikawa, Isao; Niikawa, Norio; Hoshi, Masaharu.

    1986-01-01

    A Drosophila wing spot test system was used to investigate the effects of low doses of X-rays, gamma rays, and both 2.3 and 14.1 MeV neutrons on somatic chromosome mutation (SCM) induction. The incidence of SCM was significantly increased with any type of radiation, with evident linear dose-response relationship within the range of 3 to 20 cGy. It was estimated that relative biological effectiveness value for SCM induction of 2.3 MeV neutrons to X-rays and gamma rays is much higher than that of 14.1 MeV neutrons to those photons (2.4 vs 8.0). The Drosophila wing spot test system seems to become a promising in vivo experimental method for higher animals in terms of the lack of necessity for a marvelously large number of materials required in conventional test system. (Namekawa, K.)

  15. Humidity Sensing in Drosophila.

    Science.gov (United States)

    Enjin, Anders; Zaharieva, Emanuela E; Frank, Dominic D; Mansourian, Suzan; Suh, Greg S B; Gallio, Marco; Stensmyr, Marcus C

    2016-05-23

    Environmental humidity influences the fitness and geographic distribution of all animals [1]. Insects in particular use humidity cues to navigate the environment, and previous work suggests the existence of specific sensory mechanisms to detect favorable humidity ranges [2-5]. Yet, the molecular and cellular basis of humidity sensing (hygrosensation) remains poorly understood. Here we describe genes and neurons necessary for hygrosensation in the vinegar fly Drosophila melanogaster. We find that members of the Drosophila genus display species-specific humidity preferences related to conditions in their native habitats. Using a simple behavioral assay, we find that the ionotropic receptors IR40a, IR93a, and IR25a are all required for humidity preference in D. melanogaster. Yet, whereas IR40a is selectively required for hygrosensory responses, IR93a and IR25a mediate both humidity and temperature preference. Consistent with this, the expression of IR93a and IR25a includes thermosensory neurons of the arista. In contrast, IR40a is excluded from the arista but is expressed (and required) in specialized neurons innervating pore-less sensilla of the sacculus, a unique invagination of the third antennal segment. Indeed, calcium imaging showed that IR40a neurons directly respond to changes in humidity, and IR40a knockdown or IR93a mutation reduced their responses to stimuli. Taken together, our results suggest that the preference for a specific humidity range depends on specialized sacculus neurons, and that the processing of environmental humidity can happen largely in parallel to that of temperature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Wave disc engine apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Muller, Norbert; Piechna, Janusz; Sun, Guangwei; Parraga, Pablo-Francisco

    2018-01-02

    A wave disc engine apparatus is provided. A further aspect employs a constricted nozzle in a wave rotor channel. A further aspect provides a sharp bend between an inlet and an outlet in a fluid pathway of a wave rotor, with the bend being spaced away from a peripheral edge of the wave rotor. A radial wave rotor for generating electricity in an automotive vehicle is disclosed in yet another aspect.

  17. Bilateral macular colobomata: Temporal dragging of optic disc

    Directory of Open Access Journals (Sweden)

    David J Mathew

    2015-01-01

    Full Text Available A 13-year-old male presented with decreased vision and squint from childhood. He had bilateral large colobomata at the macula in each eye, the one on the right being larger than the left. The disc was dragged temporally with straightening of the temporal retinal vessels. This is a case report of bilateral large macular coloboma and serves to report its association with a temporally dragged disc and straightened temporal retinal vessels. A dragged disc if present with a colobomatous defect at the macula may strengthen the case for diagnosis of macular coloboma and help exclude other differentials.

  18. Trapping of low-mass planets outside the truncated inner edges of protoplanetary discs

    Science.gov (United States)

    Miranda, Ryan; Lai, Dong

    2018-02-01

    We investigate the migration of a low-mass (≲10 M⊕) planet near the inner edge of a protoplanetary disc using two-dimensional viscous hydrodynamics simulations. We employ an inner boundary condition representing the truncation of the disc at the stellar corotation radius. As described by Tsang, wave reflection at the inner disc boundary modifies the Type I migration torque on the planet, allowing migration to be halted before the planet reaches the inner edge of the disc. For low-viscosity discs (α ≲ 10-3), planets may be trapped with semi-major axes as large as three to five times the inner disc radius. In general, planets are trapped closer to the inner edge as either the planet mass or the disc viscosity parameter α increases, and farther from the inner edge as the disc thickness is increased. This planet trapping mechanism may impact the formation and migration history of close-in compact multiplanet systems.

  19. Accretion discs around neutron stars

    International Nuclear Information System (INIS)

    Pringle, J.E.

    1982-01-01

    If the central object in the disc is a neutron star, then we do not need the disc itself to produce the X-rays. In other words, the disc structure itself is not important as long as it plays the role of depositing matter on the neutron star at a sufficient rate to produce the X-ray flux. Similarly, in the outer disc regions, the main disc luminosity comes from absorption and reradiation of X-ray photons and not from the intrinsic, viscously-produced, local energy production rate. These two points indicate why in the compact binary X-ray sources confrontation between disc theory and observations is not generally practicable. For this reason I will divide my talk into two parts: one on observational discs in which I discuss what observational evidence there is for discs in the compact X-ray sources and what the evidence can tell the theorist about disc behaviour, and the other on theoretical discs where I consider in what ways theoretical arguments can put limits or cast doubt on some of the empirical models put forward to explain the observations. (orig.)

  20. Quantification of Drosophila Grooming Behavior.

    Science.gov (United States)

    Barradale, Francesca; Sinha, Kairav; Lebestky, Tim

    2017-07-19

    Drosophila grooming behavior is a complex multi-step locomotor program that requires coordinated movement of both forelegs and hindlegs. Here we present a grooming assay protocol and novel chamber design that is cost-efficient and scalable for either small or large-scale studies of Drosophila grooming. Flies are dusted all over their body with Brilliant Yellow dye and given time to remove the dye from their bodies within the chamber. Flies are then deposited in a set volume of ethanol to solubilize the dye. The relative spectral absorbance of dye-ethanol samples for groomed versus ungroomed animals are measured and recorded. The protocol yields quantitative data of dye accumulation for individual flies, which can be easily averaged and compared across samples. This allows experimental designs to easily evaluate grooming ability for mutant animal studies or circuit manipulations. This efficient procedure is both versatile and scalable. We show work-flow of the protocol and comparative data between WT animals and mutant animals for the Drosophila type I Dopamine Receptor (DopR).

  1. A nanobody-based toolset to investigate the role of protein localization and dispersal in Drosophila.

    Science.gov (United States)

    Harmansa, Stefan; Alborelli, Ilaria; Bieli, Dimitri; Caussinus, Emmanuel; Affolter, Markus

    2017-04-11

    The role of protein localization along the apical-basal axis of polarized cells is difficult to investigate in vivo, partially due to lack of suitable tools. Here, we present the GrabFP system, a collection of four nanobody-based GFP-traps that localize to defined positions along the apical-basal axis. We show that the localization preference of the GrabFP traps can impose a novel localization on GFP-tagged target proteins and results in their controlled mislocalization. These new tools were used to mislocalize transmembrane and cytoplasmic GFP fusion proteins in the Drosophila wing disc epithelium and to investigate the effect of protein mislocalization. Furthermore, we used the GrabFP system as a tool to study the extracellular dispersal of the Decapentaplegic (Dpp) protein and show that the Dpp gradient forming in the lateral plane of the Drosophila wing disc epithelium is essential for patterning of the wing imaginal disc.

  2. Neurons That Underlie Drosophila melanogaster Reproductive Behaviors: Detection of a Large Male-Bias in Gene Expression in fruitless-Expressing Neurons

    Directory of Open Access Journals (Sweden)

    Nicole R. Newell

    2016-08-01

    Full Text Available Male and female reproductive behaviors in Drosophila melanogaster are vastly different, but neurons that express sex-specifically spliced fruitless transcripts (fru P1 underlie these behaviors in both sexes. How this set of neurons can generate such different behaviors between the two sexes is an unresolved question. A particular challenge is that fru P1-expressing neurons comprise only 2–5% of the adult nervous system, and so studies of adult head tissue or whole brain may not reveal crucial differences. Translating Ribosome Affinity Purification (TRAP identifies the actively translated pool of mRNAs from fru P1-expressing neurons, allowing a sensitive, cell-type-specific assay. We find four times more male-biased than female-biased genes in TRAP mRNAs from fru P1-expressing neurons. This suggests a potential mechanism to generate dimorphism in behavior. The male-biased genes may direct male behaviors by establishing cell fate in a similar context of gene expression observed in females. These results suggest a possible global mechanism for how distinct behaviors can arise from a shared set of neurons.

  3. CT discography for cervical soft disc hernia

    Energy Technology Data Exchange (ETDEWEB)

    Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

    1985-03-01

    In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five intervertebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernias between the median and posterolateral discs. They were also valuable in classifying types of hernias and surgical approaches.

  4. CT discography for cervical soft disc hernia

    International Nuclear Information System (INIS)

    Iwasa, Kenichi; Mizutani, Shigeru; Morimoto, Hiroyuki; Yamada, Hidehito; Iwasa, Satoru

    1985-01-01

    In this study the effectiveness of computed tomographic discography (CTD) in diagnosing cervical soft disc hernia was evaluated. Twenty-five interververtebral discs of 15 cases with cervical soft disc hernia were examined with a discography and then a CT scan. Results of the CT scan were as follows: three discs were protruded, 12 discs were prolapsed, 6 discs were extruded, and 4 discs were sequestrated. The findings were helpful in determining the location of soft disc hernians between the median and posterolateral discs. They were also valuable in classifying types of hernians and surgical aproaches. (author)

  5. Metabolomic Studies in Drosophila.

    Science.gov (United States)

    Cox, James E; Thummel, Carl S; Tennessen, Jason M

    2017-07-01

    Metabolomic analysis provides a powerful new tool for studies of Drosophila physiology. This approach allows investigators to detect thousands of chemical compounds in a single sample, representing the combined contributions of gene expression, enzyme activity, and environmental context. Metabolomics has been used for a wide range of studies in Drosophila , often providing new insights into gene function and metabolic state that could not be obtained using any other approach. In this review, we survey the uses of metabolomic analysis since its entry into the field. We also cover the major methods used for metabolomic studies in Drosophila and highlight new directions for future research. Copyright © 2017 by the Genetics Society of America.

  6. REDfly: a Regulatory Element Database for Drosophila.

    Science.gov (United States)

    Gallo, Steven M; Li, Long; Hu, Zihua; Halfon, Marc S

    2006-02-01

    Bioinformatics studies of transcriptional regulation in the metazoa are significantly hindered by the absence of readily available data on large numbers of transcriptional cis-regulatory modules (CRMs). Even the richly annotated Drosophila melanogaster genome lacks extensive CRM information. We therefore present here a database of Drosophila CRMs curated from the literature complete with both DNA sequence and a searchable description of the gene expression pattern regulated by each CRM. This resource should greatly facilitate the development of computational approaches to CRM discovery as well as bioinformatics analyses of regulatory sequence properties and evolution.

  7. MHD simulations of ram pressure stripping of a disc galaxy

    Science.gov (United States)

    Ramos-Martínez, Mariana; Gómez, Gilberto C.; Pérez-Villegas, Ángeles

    2018-05-01

    The removal of the interstellar medium (ISM) of disc galaxies through ram pressure stripping (RPS) has been extensively studied in numerous simulations. Nevertheless, the role of magnetic fields (MFs) on the gas dynamics in this process has been hardly studied, although the MF influence on the large-scale disc structure is well established. With this in mind, we present a 3D magnetohydrodynamic simulation of face-on RPS of a disc galaxy to study the impact of the galactic MF in the gas stripping. The main effect of including a galactic MF is a flared disc. When the intracluster medium wind hits this flared disc, oblique shocks are produced at the interaction interface, where the ISM is compressed, generating a gas inflow from large radii towards the central regions of the galaxy. This inflow is observed for {˜ } 150 {Myr} and may supply the central parts of the galaxy with material for star formation while the outskirts of the disc are being stripped of gas, thus the oblique shocks can induce and enhance the star formation in the remaining disc. We also observed that the MF alters the shape and structure of the swept gas, giving a smooth appearance in the magnetized case and clumpier and filamentary-like morphology in the hydro case. Finally, we estimated the truncation radius expected for our models using the Gunn-Gott criterion and found that that is in agreement with the simulations.

  8. Suspected herniated lumbar disc - computed tomography in differential diagnosis of non-disc-related sciatica

    International Nuclear Information System (INIS)

    Weiss, T.; Koehler, D.; Treisch, J.; Claussen, C.; Felix, R.

    1984-01-01

    The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual for unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk to overlook soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica. (orig.) [de

  9. Suspected herniated lumbar disc - computed tomography in differential diagnosis of non-disc-related sciatica

    Energy Technology Data Exchange (ETDEWEB)

    Weiss, T.; Koehler, D.; Treisch, J.; Claussen, C.; Felix, R.

    1984-07-01

    The most common reason a patient is referred for spinal CT examination is to exclude a ruptured intervertebral disc. Besides nerve root entrapment due to herniated disc, a number of unusual or unexpected conditions have been encountered in the course of CT lumbar spine studies. These include spondylolisthesis, spinal dysraphism, Paget's disease, and inflammatory, neoplastic, or metastatic lesions. The application of spinal (small-circle) target imaging includes the risk of overlooking soft tissue lesions that extend beyond the reconstruction circle. Therefore, complete (large-circle) circumferential abdominal scanning is recommended in case of a suspected extraspinal cause of sciatica.

  10. Dynamic genome wide expression profiling of Drosophila head development reveals a novel role of Hunchback in retinal glia cell development and blood-brain barrier integrity.

    Directory of Open Access Journals (Sweden)

    Montserrat Torres-Oliva

    2018-01-01

    Full Text Available Drosophila melanogaster head development represents a valuable process to study the developmental control of various organs, such as the antennae, the dorsal ocelli and the compound eyes from a common precursor, the eye-antennal imaginal disc. While the gene regulatory network underlying compound eye development has been extensively studied, the key transcription factors regulating the formation of other head structures from the same imaginal disc are largely unknown. We obtained the developmental transcriptome of the eye-antennal discs covering late patterning processes at the late 2nd larval instar stage to the onset and progression of differentiation at the end of larval development. We revealed the expression profiles of all genes expressed during eye-antennal disc development and we determined temporally co-expressed genes by hierarchical clustering. Since co-expressed genes may be regulated by common transcriptional regulators, we combined our transcriptome dataset with publicly available ChIP-seq data to identify central transcription factors that co-regulate genes during head development. Besides the identification of already known and well-described transcription factors, we show that the transcription factor Hunchback (Hb regulates a significant number of genes that are expressed during late differentiation stages. We confirm that hb is expressed in two polyploid subperineurial glia cells (carpet cells and a thorough functional analysis shows that loss of Hb function results in a loss of carpet cells in the eye-antennal disc. Additionally, we provide for the first time functional data indicating that carpet cells are an integral part of the blood-brain barrier. Eventually, we combined our expression data with a de novo Hb motif search to reveal stage specific putative target genes of which we find a significant number indeed expressed in carpet cells.

  11. Dynamic genome wide expression profiling of Drosophila head development reveals a novel role of Hunchback in retinal glia cell development and blood-brain barrier integrity

    Science.gov (United States)

    Torres-Oliva, Montserrat; Schneider, Julia; Wiegleb, Gordon

    2018-01-01

    Drosophila melanogaster head development represents a valuable process to study the developmental control of various organs, such as the antennae, the dorsal ocelli and the compound eyes from a common precursor, the eye-antennal imaginal disc. While the gene regulatory network underlying compound eye development has been extensively studied, the key transcription factors regulating the formation of other head structures from the same imaginal disc are largely unknown. We obtained the developmental transcriptome of the eye-antennal discs covering late patterning processes at the late 2nd larval instar stage to the onset and progression of differentiation at the end of larval development. We revealed the expression profiles of all genes expressed during eye-antennal disc development and we determined temporally co-expressed genes by hierarchical clustering. Since co-expressed genes may be regulated by common transcriptional regulators, we combined our transcriptome dataset with publicly available ChIP-seq data to identify central transcription factors that co-regulate genes during head development. Besides the identification of already known and well-described transcription factors, we show that the transcription factor Hunchback (Hb) regulates a significant number of genes that are expressed during late differentiation stages. We confirm that hb is expressed in two polyploid subperineurial glia cells (carpet cells) and a thorough functional analysis shows that loss of Hb function results in a loss of carpet cells in the eye-antennal disc. Additionally, we provide for the first time functional data indicating that carpet cells are an integral part of the blood-brain barrier. Eventually, we combined our expression data with a de novo Hb motif search to reveal stage specific putative target genes of which we find a significant number indeed expressed in carpet cells. PMID:29360820

  12. Genetic complexity in a Drosophila model of diabetes-associated misfolded human proinsulin.

    Science.gov (United States)

    Park, Soo-Young; Ludwig, Michael Z; Tamarina, Natalia A; He, Bin Z; Carl, Sarah H; Dickerson, Desiree A; Barse, Levi; Arun, Bharath; Williams, Calvin L; Miles, Cecelia M; Philipson, Louis H; Steiner, Donald F; Bell, Graeme I; Kreitman, Martin

    2014-02-01

    Drosophila melanogaster has been widely used as a model of human Mendelian disease, but its value in modeling complex disease has received little attention. Fly models of complex disease would enable high-resolution mapping of disease-modifying loci and the identification of novel targets for therapeutic intervention. Here, we describe a fly model of permanent neonatal diabetes mellitus and explore the complexity of this model. The approach involves the transgenic expression of a misfolded mutant of human preproinsulin, hINS(C96Y), which is a cause of permanent neonatal diabetes. When expressed in fly imaginal discs, hINS(C96Y) causes a reduction of adult structures, including the eye, wing, and notum. Eye imaginal discs exhibit defects in both the structure and the arrangement of ommatidia. In the wing, expression of hINS(C96Y) leads to ectopic expression of veins and mechano-sensory organs, indicating disruption of wild-type signaling processes regulating cell fates. These readily measurable "disease" phenotypes are sensitive to temperature, gene dose, and sex. Mutant (but not wild-type) proinsulin expression in the eye imaginal disc induces IRE1-mediated XBP1 alternative splicing, a signal for endoplasmic reticulum stress response activation, and produces global change in gene expression. Mutant hINS transgene tester strains, when crossed to stocks from the Drosophila Genetic Reference Panel, produce F1 adults with a continuous range of disease phenotypes and large broad-sense heritability. Surprisingly, the severity of mutant hINS-induced disease in the eye is not correlated with that in the notum in these crosses, nor with eye reduction phenotypes caused by the expression of two dominant eye mutants acting in two different eye development pathways, Drop (Dr) or Lobe (L), when crossed into the same genetic backgrounds. The tissue specificity of genetic variability for mutant hINS-induced disease has, therefore, its own distinct signature. The genetic dominance

  13. Gravitating discs around black holes

    International Nuclear Information System (INIS)

    Karas, V; Hure, J-M; Semerak, O

    2004-01-01

    Fluid discs and tori around black holes are discussed within different approaches and with the emphasis on the role of disc gravity. First reviewed are the prospects of investigating the gravitational field of a black hole-disc system using analytical solutions of stationary, axially symmetric Einstein equations. Then, more detailed considerations are focused to the middle and outer parts of extended disc-like configurations where relativistic effects are small and the Newtonian description is adequate. Within general relativity, only a static case has been analysed in detail. Results are often very inspiring. However, simplifying assumptions must be imposed: ad hoc profiles of the disc density are commonly assumed and the effects of frame-dragging are completely lacking. Astrophysical discs (e.g. accretion discs in active galactic nuclei) typically extend far beyond the relativistic domain and are fairly diluted. However, self-gravity is still essential for their structure and evolution, as well as for their radiation emission and the impact on the surrounding environment. For example, a nuclear star cluster in a galactic centre may bear various imprints of mutual star-disc interactions, which can be recognized in observational properties, such as the relation between the central mass and stellar velocity dispersion. (topical review)

  14. Drosophila Wnt and STAT Define Apoptosis-Resistant Epithelial Cells for Tissue Regeneration after Irradiation.

    Directory of Open Access Journals (Sweden)

    Shilpi Verghese

    2016-09-01

    Full Text Available Drosophila melanogaster larvae irradiated with doses of ionizing radiation (IR that kill about half of the cells in larval imaginal discs still develop into viable adults. How surviving cells compensate for IR-induced cell death to produce organs of normal size and appearance remains an active area of investigation. We have identified a subpopulation of cells within the continuous epithelium of Drosophila larval wing discs that shows intrinsic resistance to IR- and drug-induced apoptosis. These cells reside in domains of high Wingless (Wg, Drosophila Wnt-1 and STAT92E (sole Drosophila signal transducer and activator of transcription [STAT] homolog activity and would normally form the hinge in the adult fly. Resistance to IR-induced apoptosis requires STAT and Wg and is mediated by transcriptional repression of the pro-apoptotic gene reaper. Lineage tracing experiments show that, following irradiation, apoptosis-resistant cells lose their identity and translocate to areas of the wing disc that suffered abundant cell death. Our findings provide a new paradigm for regeneration in which it is unnecessary to invoke special damage-resistant cell types such as stem cells. Instead, differences in gene expression within a population of genetically identical epithelial cells can create a subpopulation with greater resistance, which, following damage, survive, alter their fate, and help regenerate the tissue.

  15. Black hole accretion discs and screened scalar hair

    Energy Technology Data Exchange (ETDEWEB)

    Davis, Anne-Christine; Jha, Rahul [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Gregory, Ruth, E-mail: acd@damtp.cam.ac.uk, E-mail: r.a.w.gregory@durham.ac.uk, E-mail: r.jha@damtp.cam.ac.uk [Centre for Particle Theory, Durham University, South Road, Durham, DH1 3LE (United Kingdom)

    2016-10-01

    We present a novel way to investigate scalar field profiles around black holes with an accretion disc for a range of models where the Compton wavelength of the scalar is large compared to other length scales. By analysing the problem in ''Weyl' coordinates, we are able to calculate the scalar profiles for accretion discs in the static Schwarzschild, as well as rotating Kerr, black holes. We comment on observational effects.

  16. Growth and evolution of satellites in a Jovian massive disc

    OpenAIRE

    Moraes, Ricardo A; Kley, Wilhelm; Neto, Ernesto Vieira

    2017-01-01

    The formation of satellite systems in circum-planetary discs is considered to be similar to the formation of rocky planets in a proto-planetary disc, especially Super-Earths. Thus, it is possible to use systems with large satellites to test formation theories that are also applicable to extrasolar planets. Furthermore, a better understanding of the origin of satellites might yield important information about the environment near the growing planet during the last stages of planet formation. I...

  17. Vortex survival in 3D self-gravitating accretion discs

    Science.gov (United States)

    Lin, Min-Kai; Pierens, Arnaud

    2018-04-01

    Large-scale, dust-trapping vortices may account for observations of asymmetric protoplanetary discs. Disc vortices are also potential sites for accelerated planetesimal formation by concentrating dust grains. However, in 3D discs vortices are subject to destructive `elliptic instabilities', which reduces their viability as dust traps. The survival of vortices in 3D accretion discs is thus an important issue to address. In this work, we perform shearing box simulations to show that disc self-gravity enhances the survival of 3D vortices, even when self-gravity is weak in the classic sense (e.g. with a Toomre Q ≃ 5). We find a 3D, self-gravitating vortex can grow on secular timescales in spite of the elliptic instability. The vortex aspect-ratio decreases as it strengthens, which feeds the elliptic instability. The result is a 3D vortex with a turbulent core that persists for ˜103 orbits. We find when gravitational and hydrodynamic stresses become comparable, the vortex may undergo episodic bursts, which we interpret as interaction between elliptic and gravitational instabilities. We estimate the distribution of dust particles in self-gravitating, turbulent vortices. Our results suggest large-scale vortices in protoplanetary discs are more easily observed at large radii.

  18. Orbital alignment of circumbinary planets that form in misaligned circumbinary discs: the case of Kepler-413b

    Science.gov (United States)

    Pierens, A.; Nelson, R. P.

    2018-06-01

    Although most of the circumbinary planets detected by the Kepler spacecraft are on orbits that are closely aligned with the binary orbital plane, the systems Kepler-413 and Kepler-453 exhibit small misalignments of ˜2.5°. One possibility is that these planets formed in a circumbinary disc whose midplane was inclined relative to the binary orbital plane. Such a configuration is expected to lead to a warped and twisted disc, and our aim is to examine the inclination evolution of planets embedded in these discs. We employed 3D hydrodynamical simulations that examine the disc response to the presence of a modestly inclined binary with parameters that match the Kepler-413 system, as a function of disc parameters and binary inclinations. The discs all develop slowly varying warps, and generally display very small amounts of twist. Very slow solid body precession occurs because a large outer disc radius is adopted. Simulations of planets embedded in these discs resulted in the planet aligning with the binary orbit plane for disc masses close to the minimum mass solar nebular, such that nodal precession of the planet was controlled by the binary. For higher disc masses, the planet maintains near coplanarity with the local disc midplane. Our results suggest that circumbinary planets born in tilted circumbinary discs should align with the binary orbit plane as the disc ages and loses mass, even if the circumbinary disc remains misaligned from the binary orbit. This result has important implications for understanding the origins of the known circumbinary planets.

  19. Magnetic fields in giant planet formation and protoplanetary discs

    Science.gov (United States)

    Keith, Sarah Louise

    2015-12-01

    Protoplanetary discs channel accretion onto their host star. How this is achieved is critical to the growth of giant planets which capture their massive gaseous atmosphere from the surrounding flow. Theoretical studies find that an embedded magnetic field could power accretion by hydromagnetic turbulence or torques from a large-scale field. This thesis presents a study of the inuence of magnetic fields in three key aspects of this process: circumplanetary disc accretion, gas flow across gaps in protoplanetary discs, and magnetic-braking in accretion discs. The first study examines the conditions needed for self-consistent accretion driven by magnetic fields or gravitational instability. Models of these discs typically rely on hydromagnetic turbulence as the source of effective viscosity. However, magnetically coupled,accreting regions may be so limited that the disc may not support sufficient inflow. An improved Shakura-Sunyaev ? disc is used to calculate the ionisation fraction and strength of non-ideal effects. Steady magnetically-driven accretion is limited to the thermally ionised, inner disc so that accretion in the remainder of the disc is time-dependent. The second study addresses magnetic flux transport in an accretion gap evacuated by a giant planet. Assuming the field is passively drawn along with the gas, the hydrodynamical simulation of Tanigawa, Ohtsuki & Machida (2012) is used for an a posteriori analysis of the gap field structure. This is used to post-calculate magnetohydrodynamical quantities. This assumption is self-consistent as magnetic forces are found to be weak, and good magnetic coupling ensures the field is frozen into the gas. Hall drift dominates across much of the gap, with the potential to facilitate turbulence and modify the toroidal field according to the global field orientation. The third study considers the structure and stability of magnetically-braked accretion discs. Strong evidence for MRI dead-zones has renewed interest in

  20. Björk-Shiley strut fracture and disc escape: literature review and a method of disc retrieval.

    Science.gov (United States)

    Hendel, P N

    1989-03-01

    Embolization of a prosthetic valve poppet is a rare but life-threatening event. It was reported sporadically before the introduction of the Björk-Shiley 70-degree convexoconcave prosthesis in 1980. Since that time, there have been a large number of reported mechanical failures with disc escape. The rate for the 29-mm to 33-mm mitral valves is estimated as 5.2%. In 29 of 35 patients (including the 2 presented here) in whom the site of disc lodgment could be determined, the disc was in the descending or abdominal aorta. Fifteen of these patients died. Six survivors had the disc removed at the same operation and 6 at a later operation. In 2 patients, the disc was not removed. In 2 patients in whom the disc was not removed initially, it was thought to contribute to postoperative complications. Two more cases of structural failure of the Björk-Shiley convexoconcave prosthesis are presented. A transpericardial approach to the descending aorta on bypass is described. It allows easy removal of the disc and eliminates the need for a second operation.

  1. Prevalence of disc cupping in non-glaucomatous eyes

    Directory of Open Access Journals (Sweden)

    José Pablo Chiappe

    2015-02-01

    Full Text Available This study assessed optic disc size and cupping, using a commercially available ophthalmoscope, in order to show norms of these values for clinical practice. Subjects were office-workers referred from their respective workplaces for a routine medical examination, which included eye examination. The optic disc size was classified as small, medium or large, for having a diameter 1.5 times (respectively the diameter of the ophthalmoscope's selected light spot on the posterior pole. The cupping was classified as the ratio of the vertical cupping diameter and the vertical disc diameter on a relative decimal scale from 0.0 to 1.0.This study included 184 subjects with a mean age of 40.5 ± 9.5 years; 149 (81% were males. Their mean ocular pressure was 12.4 ± 1.5 mmHg (range 10-17 mmHg. There was a high correlation between optic disc sizes and cupping in the right and left eyes (Pearson Correlation r = 0.866, p < 0.001; therefore, for simplicity only the data for right eyes are presented. According to our definition, the optic discs in these eyes comprised 27 (14.7% small, 141 (76.6% medium and 16 (8.7% large. The small optic discs were rarely cupped, and the large optic discs were always cupped. Optic disc cupping greater than 0.7 was rarely found and should be suspect of glaucoma. Clinical doctors should be aware of this and refer those subjects with abnormal cupping to the specialist.

  2. Exoplanet recycling in massive white-dwarf debris discs

    Science.gov (United States)

    van Lieshout, R.; Kral, Q.; Charnoz, S.; Wyatt, M. C.; Shannon, A.

    2018-05-01

    Several tens of white dwarfs are known to host circumstellar discs of dusty debris, thought to arise from the tidal disruption of rocky bodies originating in the star's remnant planetary system. This paper investigates the evolution of such discs if they are very massive, as may be the case if their progenitor was a terrestrial planet, moon, or dwarf planet. Assuming the discs are physically thin and flat, like Saturn's rings, their evolution is governed by Poynting-Robertson drag or viscous spreading, where the disc's effective viscosity is due to self-gravity wakes. For discs with masses ≳ 1026 g, located in the outer parts of the tidal disruption zone, viscous spreading dominates the evolution, and mass is transported both in- and outwards. When outwards-spreading material flows beyond the Roche limit, it coagulates into new (minor) planets in a process analogous to the ongoing formation of moonlets at the outer edge of Saturn's rings. The newly formed bodies migrate outwards by exchanging angular momentum with the disc and coalesce into larger objects through mutual collisions. Eventually, the disc's Roche-limit overflow recycles tens of percent of the original disc mass; most ends up in a single large body near 2:1 mean-motion resonance with the disc's outer edge. Hence, the recycling of a tidally disrupted super-Earth, for example, could yield an Earth-mass planet on a ˜10-h orbit, located in the habitable zone for 2-to-10-Gyr-old white dwarfs. The recycling process also creates a population of smaller bodies just outside the Roche limit, which may explain the minor planets recently postulated to orbit WD 1145+017.

  3. Double-disc gate valve

    International Nuclear Information System (INIS)

    Wheatley, S.J.

    1979-01-01

    The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

  4. Fluorescent visualization of macromolecules in Drosophila whole mounts.

    Science.gov (United States)

    Ramos, Ricardo Guelerman Pinheiro; Machado, Luciana Claudia Herculano; Moda, Livia Maria Rosatto

    2010-01-01

    The ability to determine the expression dynamics of individual genes "in situ" by visualizing the precise spatial and temporal distribution of their products in whole mounts by histochemical and immunocytochemical reactions has revolutionized our understanding of cellular processes. Drosophila developmental genetics was one of the fields that benefited most from these technologies, and a variety of fluorescent methods were specifically designed for investigating the localization of developmentally important proteins and cell markers during embryonic and post embryonic stages of this model organism. In this chapter we present detailed protocols for fluorescence immunocytochemistry of whole mount embryos, imaginal discs, pupal retinas, and salivary glands of Drosophila melanogaster, as well as methods for fluorescent visualization of specific subcellular structures in these tissues.

  5. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    Directory of Open Access Journals (Sweden)

    Koshi Ninomiya

    2014-01-01

    Full Text Available A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI showed a large L2/3 disc hernia descending to the L3/4 level. Compared to the initial MRI, this hernia occurred in an “intact” disc among multilevel severely degenerated discs. Right leg paresis and bladder dysfunction appeared a few days after admission. Microscopic lumbar disc herniotomy was performed. The right leg motor weakness improved just after the operation, but the moderate left leg motor weakness and difficulty in urination persisted.

  6. Abundance gradients in disc galaxies and chemical evolution models

    International Nuclear Information System (INIS)

    Diaz, A.I.

    1989-01-01

    The present state of abundance gradients and chemical evolution models of spiral galaxies is reviewed. An up to date compilation of abundance data in the literature concerning HII regions over galactic discs is presented. From these data Oxygen and Nitrogen radial gradients are computed. The slope of the Oxygen gradient is shown to have a break at a radius between 1.5 and 1.75 times the value of the effective radius of the disc, i.e. the radius containing half of the light of the disc. The gradient is steeper in the central parts of the disc and becomes flatter in the outer parts. N/O gradients are shown to be rather different from galaxy to galaxy and only a weak trend of N/O with O/H is found. The existing chemical evolution models for spiral galaxies are reviewed with special emphasis in the interpretation of numerical models having a large number of parameters. (author)

  7. Are galaxy discs optically thick?

    International Nuclear Information System (INIS)

    Disney, Michael; Davies, Jonathan; Phillipps, Steven

    1989-01-01

    We re-examine the classical optical evidence for the low optical depths traditionally assigned to spiral discs and argue that it is highly model-dependent and unconvincing. In particular, layered models with a physically thin but optically thick dust layer behave like optically thin discs. The opposite hypotheses, that such discs are optically thick is then examined in the light of modern evidence. We find it to be consistent with the near-infrared and IRAS observations, with the surface brightnesses, with the HI and CO column densities and with the Hα measurements. (author)

  8. Disc piezoelectric ceramic transformers.

    Science.gov (United States)

    Erhart, Jirií; Půlpán, Petr; Doleček, Roman; Psota, Pavel; Lédl, Vít

    2013-08-01

    In this contribution, we present our study on disc-shaped and homogeneously poled piezoelectric ceramic transformers working in planar-extensional vibration modes. Transformers are designed with electrodes divided into wedge, axisymmetrical ring-dot, moonie, smile, or yin-yang segments. Transformation ratio, efficiency, and input and output impedances were measured for low-power signals. Transformer efficiency and transformation ratio were measured as a function of frequency and impedance load in the secondary circuit. Optimum impedance for the maximum efficiency has been found. Maximum efficiency and no-load transformation ratio can reach almost 100% and 52 for the fundamental resonance of ring-dot transformers and 98% and 67 for the second resonance of 2-segment wedge transformers. Maximum efficiency was reached at optimum impedance, which is in the range from 500 Ω to 10 kΩ, depending on the electrode pattern and size. Fundamental vibration mode and its overtones were further studied using frequency-modulated digital holographic interferometry and by the finite element method. Complementary information has been obtained by the infrared camera visualization of surface temperature profiles at higher driving power.

  9. Disc Golf: Teaching a Lifetime Activity

    Science.gov (United States)

    Eastham, Susan L.

    2015-01-01

    Disc golf is a lifetime activity that can be enjoyed by students of varying skill levels and abilities. Disc golf follows the principles of ball golf but is generally easier for students to play and enjoy success. The object of disc golf is similar to ball golf and involves throwing a disc from the teeing area to the target in as few throws as…

  10. Transient events in bright debris discs: Collisional avalanches revisited

    Science.gov (United States)

    Thebault, P.; Kral, Q.

    2018-01-01

    Context. A collisional avalanche is set off by the breakup of a large planetesimal, releasing vast amounts of small unbound grains that enter a debris disc located further away from the star, triggering there a collisional chain reaction that could potentially create detectable transient structures. Aims: We investigate this mechanism, using for the first time a fully self-consistent code coupling dynamical and collisional evolutions. We also quantify for the first time the photometric evolution of the system and investigate whether or not avalanches could explain the short-term luminosity variations recently observed in some extremely bright debris discs. Methods: We use the state-of-the-art LIDT-DD code. We consider an avalanche-favoring A6V star, and two set-ups: a "cold disc" case, with a dust release at 10 au and an outer disc extending from 50 to 120 au, and a "warm disc" case with the release at 1 au and a 5-12 au outer disc. We explore, in addition, two key parameters: the density (parameterized by its optical depth τ) of the main outer disc and the amount of dust released by the initial breakup. Results: We find that avalanches could leave detectable structures on resolved images, for both "cold" and "warm" disc cases, in discs with τ of a few 10-3, provided that large dust masses (≳1020-5 × 1022 g) are initially released. The integrated photometric excess due to an avalanche is relatively limited, less than 10% for these released dust masses, peaking in the λ 10-20 μm domain and becoming insignificant beyond 40-50 μm. Contrary to earlier studies, we do not obtain stronger avalanches when increasing τ to higher values. Likewise, we do not observe a significant luminosity deficit, as compared to the pre-avalanche level, after the passage of the avalanche. These two results concur to make avalanches an unlikely explanation for the sharp luminosity drops observed in some extremely bright debris discs. The ideal configuration for observing an

  11. Hearing regulates Drosophila aggression.

    Science.gov (United States)

    Versteven, Marijke; Vanden Broeck, Lies; Geurten, Bart; Zwarts, Liesbeth; Decraecker, Lisse; Beelen, Melissa; Göpfert, Martin C; Heinrich, Ralf; Callaerts, Patrick

    2017-02-21

    Aggression is a universal social behavior important for the acquisition of food, mates, territory, and social status. Aggression in Drosophila is context-dependent and can thus be expected to involve inputs from multiple sensory modalities. Here, we use mechanical disruption and genetic approaches in Drosophila melanogaster to identify hearing as an important sensory modality in the context of intermale aggressive behavior. We demonstrate that neuronal silencing and targeted knockdown of hearing genes in the fly's auditory organ elicit abnormal aggression. Further, we show that exposure to courtship or aggression song has opposite effects on aggression. Our data define the importance of hearing in the control of Drosophila intermale aggression and open perspectives to decipher how hearing and other sensory modalities are integrated at the neural circuit level.

  12. Developmental regulation of nucleolus size during Drosophila eye differentiation.

    Directory of Open Access Journals (Sweden)

    Nicholas E Baker

    Full Text Available When cell cycle withdrawal accompanies terminal differentiation, biosynthesis and cellular growth are likely to change also. In this study, nucleolus size was monitored during cell fate specification in the Drosophila eye imaginal disc using fibrillarin antibody labeling. Nucleolus size is an indicator of ribosome biogenesis and can correlate with cellular growth rate. Nucleolar size was reduced significantly during cell fate specification and differentiation, predominantly as eye disc cells entered a cell cycle arrest that preceded cell fate specification. This reduction in nucleolus size required Dpp and Hh signaling. A transient enlargement of the nucleolus accompanied cell division in the Second Mitotic Wave. Nucleoli continued to diminish in postmitotic cells following fate specification. These results suggest that cellular growth is regulated early in the transition from proliferating progenitor cells to terminal cell fate specification, contemporary with regulation of the cell cycle, and requiring the same extracellular signals.

  13. Developmental regulation of nucleolus size during Drosophila eye differentiation.

    Science.gov (United States)

    Baker, Nicholas E

    2013-01-01

    When cell cycle withdrawal accompanies terminal differentiation, biosynthesis and cellular growth are likely to change also. In this study, nucleolus size was monitored during cell fate specification in the Drosophila eye imaginal disc using fibrillarin antibody labeling. Nucleolus size is an indicator of ribosome biogenesis and can correlate with cellular growth rate. Nucleolar size was reduced significantly during cell fate specification and differentiation, predominantly as eye disc cells entered a cell cycle arrest that preceded cell fate specification. This reduction in nucleolus size required Dpp and Hh signaling. A transient enlargement of the nucleolus accompanied cell division in the Second Mitotic Wave. Nucleoli continued to diminish in postmitotic cells following fate specification. These results suggest that cellular growth is regulated early in the transition from proliferating progenitor cells to terminal cell fate specification, contemporary with regulation of the cell cycle, and requiring the same extracellular signals.

  14. Lumbar disc excision through fenestration

    Directory of Open Access Journals (Sweden)

    Sangwan S

    2006-01-01

    Full Text Available Background : Lumbar disc herniation often causes sciatica. Many different techniques have been advocated with the aim of least possible damage to other structures while dealing with prolapsed disc surgically in the properly selected and indicated cases. Methods : Twenty six patients with clinical symptoms and signs of prolapsed lumbar intervertebral disc having radiological correlation by MRI study were subjected to disc excision by interlaminar fenestration method. Results : The assessment at follow-up showed excellent results in 17 patients, good in 6 patients, fair in 2 patients and poor in 1 patient. The mean preoperative and postoperative Visual Analogue Scores were 9.34 ±0.84 and 2.19 ±0.84 on scale of 0-10 respectively. These were statistically significant (p value< 0.001, paired t test. No significant complications were recorded. Conclusion : Procedures of interlaminar fenestration and open disc excision under direct vision offers sufficient adequate exposure for lumbar disc excision with a smaller incision, lesser morbidity, shorter convalescence, early return to work and comparable overall results in the centers where recent laser and endoscopy facilities are not available.

  15. Comparison of Animal Discs Used in Disc Research to Human Lumbar Disc: Torsion Mechanics and Collagen Content

    Science.gov (United States)

    Showalter, Brent L.; Beckstein, Jesse C.; Martin, John T.; Beattie, Elizabeth E.; Orías, Alejandro A. Espinoza; Schaer, Thomas P.; Vresilovic, Edward J.; Elliott, Dawn M.

    2012-01-01

    Study Design Experimental measurement and normalization of in vitro disc torsion mechanics and collagen content for several animal species used in intervertebral disc research and comparing these to the human disc. Objective To aid in the selection of appropriate animal models for disc research by measuring torsional mechanical properties and collagen content. Summary of Background Data There is lack of data and variability in testing protocols for comparing animal and human disc torsion mechanics and collagen content. Methods Intervertebral disc torsion mechanics were measured and normalized by disc height and polar moment of inertia for 11 disc types in 8 mammalian species: the calf, pig, baboon, goat, sheep, rabbit, rat, and mouse lumbar, and cow, rat, and mouse caudal. Collagen content was measured and normalized by dry weight for the same discs except the rat and mouse. Collagen fiber stretch in torsion was calculated using an analytical model. Results Measured torsion parameters varied by several orders of magnitude across the different species. After geometric normalization, only the sheep and pig discs were statistically different from human. Fiber stretch was found to be highly dependent on the assumed initial fiber angle. The collagen content of the discs was similar, especially in the outer annulus where only the calf and goat discs were statistically different from human. Disc collagen content did not correlate with torsion mechanics. Conclusion Disc torsion mechanics are comparable to human lumbar discs in 9 of 11 disc types after normalization by geometry. The normalized torsion mechanics and collagen content of the multiple animal discs presented is useful for selecting and interpreting results for animal models of the disc. Structural composition of the disc, such as initial fiber angle, may explain the differences that were noted between species after geometric normalization. PMID:22333953

  16. The use of genetic algorithms to model protoplanetary discs

    Science.gov (United States)

    Hetem, Annibal; Gregorio-Hetem, Jane

    2007-12-01

    The protoplanetary discs of T Tauri and Herbig Ae/Be stars have previously been studied using geometric disc models to fit their spectral energy distribution (SED). The simulations provide a means to reproduce the signatures of various circumstellar structures, which are related to different levels of infrared excess. With the aim of improving our previous model, which assumed a simple flat-disc configuration, we adopt here a reprocessing flared-disc model that assumes hydrostatic, radiative equilibrium. We have developed a method to optimize the parameter estimation based on genetic algorithms (GAs). This paper describes the implementation of the new code, which has been applied to Herbig stars from the Pico dos Dias Survey catalogue, in order to illustrate the quality of the fitting for a variety of SED shapes. The star AB Aur was used as a test of the GA parameter estimation, and demonstrates that the new code reproduces successfully a canonical example of the flared-disc model. The GA method gives a good quality of fit, but the range of input parameters must be chosen with caution, as unrealistic disc parameters can be derived. It is confirmed that the flared-disc model fits the flattened SEDs typical of Herbig stars; however, embedded objects (increasing SED slope) and debris discs (steeply decreasing SED slope) are not well fitted with this configuration. Even considering the limitation of the derived parameters, the automatic process of SED fitting provides an interesting tool for the statistical analysis of the circumstellar luminosity of large samples of young stars.

  17. Origin of chemically distinct discs in the Auriga cosmological simulations

    Science.gov (United States)

    Grand, Robert J. J.; Bustamante, Sebastián; Gómez, Facundo A.; Kawata, Daisuke; Marinacci, Federico; Pakmor, Rüdiger; Rix, Hans-Walter; Simpson, Christine M.; Sparre, Martin; Springel, Volker

    2018-03-01

    The stellar disc of the Milky Way shows complex spatial and abundance structure that is central to understanding the key physical mechanisms responsible for shaping our Galaxy. In this study, we use six very high resolution cosmological zoom-in simulations of Milky Way-sized haloes to study the prevalence and formation of chemically distinct disc components. We find that our simulations develop a clearly bimodal distribution in the [α/Fe]-[Fe/H] plane. We find two main pathways to creating this dichotomy, which operate in different regions of the galaxies: (a) an early (z > 1) and intense high-[α/Fe] star formation phase in the inner region (R ≲ 5 kpc) induced by gas-rich mergers, followed by more quiescent low-[α/Fe] star formation; and (b) an early phase of high-[α/Fe] star formation in the outer disc followed by a shrinking of the gas disc owing to a temporarily lowered gas accretion rate, after which disc growth resumes. In process (b), a double-peaked star formation history around the time and radius of disc shrinking accentuates the dichotomy. If the early star formation phase is prolonged (rather than short and intense), chemical evolution proceeds as per process (a) in the inner region, but the dichotomy is less clear. In the outer region, the dichotomy is only evident if the first intense phase of star formation covers a large enough radial range before disc shrinking occurs; otherwise, the outer disc consists of only low-[α/Fe] sequence stars. We discuss the implication that both processes occurred in the Milky Way.

  18. Evolution of viscous discs. 3. Giant discs in symbiotic stars

    Energy Technology Data Exchange (ETDEWEB)

    Bath, G T [Oxford Univ. (UK). Dept. of Astrophysics; Pringle, J E [Cambridge Univ. (UK). Inst. of Astronomy

    1982-10-01

    The structure of time-dependent accretion discs in giant binaries with separation of the order of 10/sup 13/ cm is examined. Radiative ..cap alpha..-viscosity discs with ..cap alpha.. of order unity accreting on to main-sequence stars at accretion rates which generate luminosities greater than a giant companion decay on time-scales of the same order as the binary period, unlike those in dwarf nova binaries which decay on time-scales 100 times longer than the binary period. This results from the lower gravitational potential and consequent larger disc thickness (relative to the radius) of luminous 'giant' discs accreting at high accretion rates. The eruptions of the symbiotic binary C I Cygni are modelled by an ..cap alpha.. = 1 disc with outer radius 8.5 x 10/sup 12/ cm and a sequence of five mass-transfer bursts at rates between 1.5 x 10/sup 21/ and 4 x 10/sup 22/g s/sup -1/.

  19. BMAA neurotoxicity in Drosophila.

    Science.gov (United States)

    Zhou, Xianchong; Escala, Wilfredo; Papapetropoulos, Spyridon; Bradley, Walter G; Zhai, R Grace

    2009-01-01

    We report the establishment of an in vivo model using the fruit fly Drosophila melanogaster to investigate the toxic effects of L-BMAA. We found that dietary intake of BMAA reduced the lifespan as well as the neurological functions of flies. Furthermore, we have developed an HPLC method to reliably detect both free and protein-bound BMAA in fly tissue extracts.

  20. Cancer in Drosophila

    DEFF Research Database (Denmark)

    Herranz, Héctor; Eichenlaub, Teresa; Cohen, Stephen M

    2016-01-01

    Cancer genomics has greatly increased our understanding of the complexity of the genetic and epigenetic changes found in human tumors. Understanding the functional relationships among these elements calls for the use of flexible genetic models. We discuss the use of Drosophila models to study...

  1. dFOXO Activates Large and Small Heat Shock Protein Genes in Response to Oxidative Stress to Maintain Proteostasis in Drosophila.

    Science.gov (United States)

    Donovan, Marissa R; Marr, Michael T

    2016-09-02

    Maintaining protein homeostasis is critical for survival at the cellular and organismal level (Morimoto, R. I. (2011) Cold Spring Harb. Symp. Quant. Biol. 76, 91-99). Cells express a family of molecular chaperones, the heat shock proteins, during times of oxidative stress to protect against proteotoxicity. We have identified a second stress responsive transcription factor, dFOXO, that works alongside the heat shock transcription factor to activate transcription of both the small heat shock protein and the large heat shock protein genes. This expression likely protects cells from protein misfolding associated with oxidative stress. Here we identify the regions of the Hsp70 promoter essential for FOXO-dependent transcription using in vitro methods and find a physiological role for FOXO-dependent expression of heat shock proteins in vivo. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  2. Modeling Human Cancers in Drosophila.

    Science.gov (United States)

    Sonoshita, M; Cagan, R L

    2017-01-01

    Cancer is a complex disease that affects multiple organs. Whole-body animal models provide important insights into oncology that can lead to clinical impact. Here, we review novel concepts that Drosophila studies have established for cancer biology, drug discovery, and patient therapy. Genetic studies using Drosophila have explored the roles of oncogenes and tumor-suppressor genes that when dysregulated promote cancer formation, making Drosophila a useful model to study multiple aspects of transformation. Not limited to mechanism analyses, Drosophila has recently been showing its value in facilitating drug development. Flies offer rapid, efficient platforms by which novel classes of drugs can be identified as candidate anticancer leads. Further, we discuss the use of Drosophila as a platform to develop therapies for individual patients by modeling the tumor's genetic complexity. Drosophila provides both a classical and a novel tool to identify new therapeutics, complementing other more traditional cancer tools. © 2017 Elsevier Inc. All rights reserved.

  3. A genomic investigation of ecological differentiation between free-living and Drosophila-associated bacteria.

    Science.gov (United States)

    Winans, Nathan J; Walter, Alec; Chouaia, Bessem; Chaston, John M; Douglas, Angela E; Newell, Peter D

    2017-09-01

    Various bacterial taxa have been identified both in association with animals and in the external environment, but the extent to which related bacteria from the two habitat types are ecologically and evolutionarily distinct is largely unknown. This study investigated the scale and pattern of genetic differentiation between bacteria of the family Acetobacteraceae isolated from the guts of Drosophila fruit flies, plant material and industrial fermentations. Genome-scale analysis of the phylogenetic relationships and predicted functions was conducted on 44 Acetobacteraceae isolates, including newly sequenced genomes from 18 isolates from wild and laboratory Drosophila. Isolates from the external environment and Drosophila could not be assigned to distinct phylogenetic groups, nor are their genomes enriched for any different sets of genes or category of predicted gene functions. In contrast, analysis of bacteria from laboratory Drosophila showed they were genetically distinct in their universal capacity to degrade uric acid (a major nitrogenous waste product of Drosophila) and absence of flagellar motility, while these traits vary among wild Drosophila isolates. Analysis of the competitive fitness of Acetobacter discordant for these traits revealed a significant fitness deficit for bacteria that cannot degrade uric acid in culture with Drosophila. We propose that, for wild populations, frequent cycling of Acetobacter between Drosophila and the external environment prevents genetic differentiation by maintaining selection for traits adaptive in both the gut and external habitats. However, laboratory isolates bear the signs of adaptation to persistent association with the Drosophila host under tightly defined environmental conditions. © 2017 John Wiley & Sons Ltd.

  4. Adaptive control of the radial servo system of a compact disc player

    NARCIS (Netherlands)

    Draijer, W.; Steinbuch, M.; Bosgra, O.H.

    1992-01-01

    The radial servo system of a compact disc player has to cope with large gain variations which are due to disc dependent optical characteristics, tolerances in mechanical and electrical components and nonlinearity in the generation of the position index. In current players this problem has been

  5. Vertebral osteomyelitis without disc involvement

    Energy Technology Data Exchange (ETDEWEB)

    Kamani, I.; Syed, I.; Saifuddin, A. E-mail: asaifuddin@aol.com; Green, R.; MacSweeney, F

    2004-10-01

    Vertebral osteomyelitis is most commonly due to pyogenic or granulomatous infection and typically results in the combined involvement of the intervertebral disc and adjacent vertebral bodies. Non-infective causes include the related conditions of chronic recurrent multifocal osteomyelitis (CRMO) and SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome. Occasionally, these conditions may present purely within the vertebral body, resulting in various combinations of vertebral marrow oedema and sclerosis, destructive lesions of the vertebral body and pathological vertebral collapse, thus mimicking neoplastic disease. This review illustrates the imaging features of vertebral osteomyelitis without disc involvement, with emphasis on magnetic resonance imaging (MRI) findings.

  6. Biomechanical analysis of the camelid cervical intervertebral disc

    Directory of Open Access Journals (Sweden)

    Dean K. Stolworthy

    2015-01-01

    Full Text Available Chronic low back pain (LBP is a prevalent global problem, which is often correlated with degenerative disc disease. The development and use of good, relevant animal models of the spine may improve treatment options for this condition. While no animal model is capable of reproducing the exact biology, anatomy, and biomechanics of the human spine, the quality of a particular animal model increases with the number of shared characteristics that are relevant to the human condition. The purpose of this study was to investigate the camelid (specifically, alpaca and llama cervical spine as a model of the human lumbar spine. Cervical spines were obtained from four alpacas and four llamas and individual segments were used for segmental flexibility/biomechanics and/or morphology/anatomy studies. Qualitative and quantitative data were compared for the alpaca and llama cervical spines, and human lumbar specimens in addition to other published large animal data. Results indicate that a camelid cervical intervertebral disc (IVD closely approximates the human lumbar disc with regard to size, spinal posture, and biomechanical flexibility. Specifically, compared with the human lumbar disc, the alpaca and llama cervical disc size are approximately 62%, 83%, and 75% with regard to area, depth, and width, respectively, and the disc flexibility is approximately 133%, 173%, and 254%, with regard to range of motion (ROM in axial-rotation, flexion-extension, and lateral-bending, respectively. These results, combined with the clinical report of disc degeneration in the llama lower cervical spine, suggest that the camelid cervical spine is potentially well suited for use as an animal model in biomechanical studies of the human lumbar spine.

  7. Adaptive Evolution of Gene Expression in Drosophila

    Directory of Open Access Journals (Sweden)

    Armita Nourmohammad

    2017-08-01

    Full Text Available Gene expression levels are important quantitative traits that link genotypes to molecular functions and fitness. In Drosophila, population-genetic studies have revealed substantial adaptive evolution at the genomic level, but the evolutionary modes of gene expression remain controversial. Here, we present evidence that adaptation dominates the evolution of gene expression levels in flies. We show that 64% of the observed expression divergence across seven Drosophila species are adaptive changes driven by directional selection. Our results are derived from time-resolved data of gene expression divergence across a family of related species, using a probabilistic inference method for gene-specific selection. Adaptive gene expression is stronger in specific functional classes, including regulation, sensory perception, sexual behavior, and morphology. Moreover, we identify a large group of genes with sex-specific adaptation of expression, which predominantly occurs in males. Our analysis opens an avenue to map system-wide selection on molecular quantitative traits independently of their genetic basis.

  8. Phospho-regulated Drosophila adducin is a determinant of synaptic plasticity in a complex with Dlg and PIP2 at the larval neuromuscular junction

    Directory of Open Access Journals (Sweden)

    Simon Ji Hau Wang

    2014-11-01

    Full Text Available Adducin is a ubiquitously expressed actin- and spectrin-binding protein involved in cytoskeleton organization, and is regulated through phosphorylation of the myristoylated alanine-rich C-terminal kinase (MARCKS-homology domain by protein kinase C (PKC. We have previously shown that the Drosophila adducin, Hu-li tai shao (Hts, plays a role in larval neuromuscular junction (NMJ growth. Here, we find that the predominant isoforms of Hts at the NMJ contain the MARCKS-homology domain, which is important for interactions with Discs large (Dlg and phosphatidylinositol 4,5-bisphosphate (PIP2. Through the use of Proximity Ligation Assay (PLA, we show that the adducin-like Hts isoforms are in complexes with Dlg and PIP2 at the NMJ. We provide evidence that Hts promotes the phosphorylation and delocalization of Dlg at the NMJ through regulation of the transcript distribution of the PAR-1 and CaMKII kinases in the muscle. We also show that Hts interactions with Dlg and PIP2 are impeded through phosphorylation of the MARCKS-homology domain. These results are further evidence that Hts is a signaling-responsive regulator of synaptic plasticity in Drosophila.

  9. Cell type-specific recruitment of Drosophila Lin-7 to distinct MAGUK-based protein complexes defines novel roles for Sdt and Dlg-S97.

    Science.gov (United States)

    Bachmann, André; Timmer, Marco; Sierralta, Jimena; Pietrini, Grazia; Gundelfinger, Eckart D; Knust, Elisabeth; Thomas, Ulrich

    2004-04-15

    Stardust (Sdt) and Discs-Large (Dlg) are membrane-associated guanylate kinases (MAGUKs) involved in the organization of supramolecular protein complexes at distinct epithelial membrane compartments in Drosophila. Loss of either Sdt or Dlg affects epithelial development with severe effects on apico-basal polarity. Moreover, Dlg is required for the structural and functional integrity of synaptic junctions. Recent biochemical and cell culture studies have revealed that various mammalian MAGUKs can interact with mLin-7/Veli/MALS, a small PDZ-domain protein. To substantiate these findings for their in vivo significance with regard to Sdt- and Dlg-based protein complexes, we analyzed the subcellular distribution of Drosophila Lin-7 (DLin-7) and performed genetic and biochemical assays to characterize its interaction with either of the two MAGUKs. In epithelia, Sdt mediates the recruitment of DLin-7 to the subapical region, while at larval neuromuscular junctions, a particular isoform of Dlg, Dlg-S97, is required for postsynaptic localization of DLin-7. Ectopic expression of Dlg-S97 in epithelia, however, was not sufficient to induce a redistribution of DLin-7. These results imply that the recruitment of DLin-7 to MAGUK-based protein complexes is defined by cell-type specific mechanisms and that DLin-7 acts downstream of Sdt in epithelia and downstream of Dlg at synapses.

  10. A perisynaptic ménage à trois between Dlg, DLin-7, and Metro controls proper organization of Drosophila synaptic junctions.

    Science.gov (United States)

    Bachmann, André; Kobler, Oliver; Kittel, Robert J; Wichmann, Carolin; Sierralta, Jimena; Sigrist, Stephan J; Gundelfinger, Eckart D; Knust, Elisabeth; Thomas, Ulrich

    2010-04-28

    Structural plasticity of synaptic junctions is a prerequisite to achieve and modulate connectivity within nervous systems, e.g., during learning and memory formation. It demands adequate backup systems that allow remodeling while retaining sufficient stability to prevent unwanted synaptic disintegration. The strength of submembranous scaffold complexes, which are fundamental to the architecture of synaptic junctions, likely constitutes a crucial determinant of synaptic stability. Postsynaptic density protein-95 (PSD-95)/ Discs-large (Dlg)-like membrane-associated guanylate kinases (DLG-MAGUKs) are principal scaffold proteins at both vertebrate and invertebrate synapses. At Drosophila larval glutamatergic neuromuscular junctions (NMJs) DlgA and DlgS97 exert pleiotropic functions, probably reflecting a few known and a number of yet-unknown binding partners. In this study we have identified Metro, a novel p55/MPP-like Drosophila MAGUK as a major binding partner of perisynaptic DlgS97 at larval NMJs. Based on homotypic LIN-2,-7 (L27) domain interactions, Metro stabilizes junctional DlgS97 in a complex with the highly conserved adaptor protein DLin-7. In a remarkably interdependent manner, Metro and DLin-7 act downstream of DlgS97 to control NMJ expansion and proper establishment of synaptic boutons. Using quantitative 3D-imaging we further demonstrate that the complex controls the size of postsynaptic glutamate receptor fields. Our findings accentuate the importance of perisynaptic scaffold complexes for synaptic stabilization and organization.

  11. Drosophila Myc is required for normal DREF gene expression

    International Nuclear Information System (INIS)

    Dang Thi Phuong Thao; Seto, Hirokazu; Yamaguchi, Masamitsu

    2008-01-01

    The Drosophila DNA replication-related element-binding factor (dDREF) is required for the expression of many proliferation-related genes carrying the DRE sequence, 5'-TATCGATA. Finding a canonical E-box, 5'-CACGTG, in the dDREF gene promoter prompted us to explore the possibility that the dDREF gene is a target of Drosophila Myc (dMyc). Luciferase transient expression assays combined with RNA interference in Drosophila S2 cells revealed that knockdown of dmyc reduced dDREF gene promoter activity by 35% to 82%, an effect at least partly mediated by the E-box in the promoter. dm 4 /Y hemizygous mutant larvae demonstrated no maternal dMyc and severe impairment of dDREF mRNA transcription. dMyc loss of function in dm 2 /dm 2 homozygous mutant follicle cell clones also resulted in loss of anti-dDREF immunostaining in nuclei. In contrast, co-expression of dMyc-dMax up-regulated dDREF promoter activity in S2 cells. Furthermore, dMyc over-expressing clones exhibited a high level of dDREF gene expression in wing and eye discs. These results taken together indicate that dMyc is indeed required for dDREF gene expression

  12. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, N.

    2011-01-01

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  13. Intervertebral disc degeneration in dogs

    NARCIS (Netherlands)

    Bergknut, Niklas

    Back pain is common in both dogs and humans, and is often associated with intervertebral disc (IVD) degeneration. The IVDs are essential structures of the spine and degeneration can ultimately result in diseases such as IVD herniation or spinal instability. In order to design new treatments halting

  14. CT morphometry of adult thoracic intervertebral discs.

    Science.gov (United States)

    Fletcher, Justin G R; Stringer, Mark D; Briggs, Christopher A; Davies, Tilman M; Woodley, Stephanie J

    2015-10-01

    Despite being commonly affected by degenerative disorders, there are few data on normal thoracic intervertebral disc dimensions. A morphometric analysis of adult thoracic intervertebral discs was, therefore, undertaken. Archival computed tomography scans of 128 recently deceased individuals (70 males, 58 females, 20-79 years) with no known spinal pathology were analysed to determine thoracic disc morphometry and variations with disc level, sex and age. Reliability was assessed by intraclass correlation coefficients (ICCs). Anterior and posterior intervertebral disc heights and axial dimensions were significantly greater in men (anterior disc height 4.0±1.4 vs 3.6±1.3 mm; posterior disc height 3.6±0.90 vs 3.4±0.93 mm; p<0.01). Disc heights and axial dimensions at T4-5 were similar or smaller than at T2-3, but thereafter increased caudally (mean anterior disc height T4-5 and T10-11, 2.7±0.7 and 5.4±1.2 mm, respectively, in men; 2.6±0.8 and 5.1±1.3 mm, respectively, in women; p<0.05). Except at T2-3, anterior disc height decreased with advancing age and anteroposterior and transverse disc dimensions increased; posterior and middle disc heights and indices of disc shape showed no consistent statistically significant changes. Most parameters showed substantial to almost perfect agreement for intra- and inter-rater reliability. Thoracic disc morphometry varies significantly and consistently with disc level, sex and age. This study provides unique reference data on adult thoracic intervertebral disc morphometry, which may be useful when interpreting pathological changes and for future biomechanical and functional studies.

  15. The origin of extended disc galaxies at z=2

    NARCIS (Netherlands)

    Sales, Laura V.; Navarro, Julio F.; Schaye, Joop; Dalla Vecchia, Claudio; Springel, Volker; Haas, Marcel R.; Helmi, Amina

    2009-01-01

    Galaxy formation models typically assume that the size and rotation speed of galaxy discs are largely dictated by the mass, concentration and spin of their surrounding dark matter haloes. Equally important, however, is the fraction of baryons in the halo that collect into the central galaxy, as well

  16. Disc degeneration: current surgical options

    Directory of Open Access Journals (Sweden)

    C Schizas

    2010-10-01

    Full Text Available Chronic low back pain attributed to lumbar disc degeneration poses a serious challenge to physicians. Surgery may be indicated in selected cases following failure of appropriate conservative treatment. For decades, the only surgical option has been spinal fusion, but its results have been inconsistent. Some prospective trials show superiority over usual conservative measures while others fail to demonstrate its advantages. In an effort to improve results of fusion and to decrease the incidence of adjacent segment degeneration, total disc replacement techniques have been introduced and studied extensively. Short-term results have shown superiority over some fusion techniques. Mid-term results however tend to show that this approach yields results equivalent to those of spinal fusion. Nucleus replacement has gained some popularity initially, but evidence on its efficacy is scarce. Dynamic stabilisation, a technique involving less rigid implants than in spinal fusion and performed without the need for bone grafting, represents another surgical option. Evidence again is lacking on its superiority over other surgical strategies and conservative measures. Insertion of interspinous devices posteriorly, aiming at redistributing loads and relieving pain, has been used as an adjunct to disc removal surgery for disc herniation. To date however, there is no clear evidence on their efficacy. Minimally invasive intradiscal thermocoagulation techniques have also been tried, but evidence of their effectiveness is questioned. Surgery using novel biological solutions may be the future of discogenic pain treatment. Collaboration between clinicians and basic scientists in this multidisciplinary field will undoubtedly shape the future of treating symptomatic disc degeneration.

  17. Silver nano fabrication using leaf disc of Passiflora foetida Linn

    Science.gov (United States)

    Lade, Bipin D.; Patil, Anita S.

    2017-06-01

    The main purpose of the experiment is to develop a greener low cost SNP fabrication steps using factories of secondary metabolites from Passiflora leaf extract. Here, the leaf extraction process is omitted, and instead a leaf disc was used for stable SNP fabricated by optimizing parameters such as a circular leaf disc of 2 cm (1, 2, 3, 4, 5) instead of leaf extract and grade of pH (7, 8, 9, 11). The SNP synthesis reaction is tried under room temperature, sun, UV and dark condition. The leaf disc preparation steps are also discussed in details. The SNP obtained using (1 mM: 100 ml AgNO3+ singular leaf disc: pH 9, 11) is applied against featured room temperature and sun condition. The UV spectroscopic analysis confirms that sun rays synthesized SNP yields stable nano particles. The FTIR analysis confirms a large number of functional groups such as alkanes, alkyne, amines, aliphatic amine, carboxylic acid; nitro-compound, alcohol, saturated aldehyde and phenols involved in reduction of silver salt to zero valent ions. The leaf disc mediated synthesis of silver nanoparticles, minimizes leaf extract preparation step and eligible for stable SNP synthesis. The methods sun and room temperature based nano particles synthesized within 10 min would be use certainly for antimicrobial activity.

  18. CT findings of lumbar intervertebral disc: II. Disc herniation (HNP)

    International Nuclear Information System (INIS)

    Yang, W. J.; Lee, J. M.; Bahk, Y. W.

    1984-01-01

    In lumbar region the epidural fat pad is relatively abundant so that CT can provides sufficient information in diagnosis of lumbar HNP. Many authors have reported on the CT findings of HNP such as focal nodular protrusion of the posterior disc margin, obliteration of epidural fat pad, impingement of dural sac and nerve root, swelling of nerve root, soft tissue density in the spinal canal and calcification of disc. However there was so previous report describing incidence and reliability of the findings. It is the purpose of the present study to survey the frequency, reliability, and limitation of these CT findings. The clinical material was consisted of 30 operatively proven cases of HNP of the lumbar spine. Each lumbar CT scan was reviewed retrospectively and the findings were analysed by two radiologists independently. There were 20 males and 10 females and the mean age was 36.7 years. Involvement of L4-S5 level was 2.3 times more frequent than that of L5-S1 level. Of 30 cases, 22 were unilateral posterolateral types and 8 cases central or unilateral far lateral types. CT findings observed were nodular protrusion of the posterior margin of the disc, obliteration of epidural fat pad, impingement of dural sac or nerve root, soft tissue density in the spinal canal and calcification in the posterior portion of the protruded disc, in order of decreasing frequency. The conclusions are follows: 1. Nodular protrusion of the posterior disc margin accompanied by obliteration of epidural fat pad was observed in every case. The former findings was designated as direct sign and the latter indirect. 2. Obliteration of the epidural fat appears to be significant in lateral recesses especially when it occurs unilaterally. This was not true, however, in the centrally located fat pad. 3. Impingement of the dural sac and nerve root were observed in 90% and 67%, respectively, and were very helpful in establishing HNP diagnosis when the direct and indirect signs were equivocal

  19. Brown dwarfs forming in discs: Where to look for them?

    Directory of Open Access Journals (Sweden)

    Stamatellos D.

    2011-07-01

    Full Text Available A large fraction of the observed brown dwarfs may form by gravitational fragmentation of unstable discs. This model reproduces the brown dwarf desert, and provides an explanation for the existence of planetary-mass objects and for the binary properties of low-mass objects. We have performed an ensemble of radiative hydrodynamic simulations and determined the statistical properties of the low-mass objects produced by gravitational fragmentation of discs. We suggest that there is a population of brown dwarfs loosely bound on wide orbits (100–5000 AU around Sun-like stars that surveys of brown dwarf companions should target. Our simulations also indicate that planetary-mass companions to Sun-like stars are unlikely to form by disc fragmentation.

  20. Noonan's syndrome with keratoconus and optic disc coloboma.

    Science.gov (United States)

    Ascaso, F J; Del Buey, M A; Huerva, V; Latre, B; Palomar, A

    1993-01-01

    We report the case of a 14-year-old girl with multiple findings characteristic of Noonan's syndrome, including short stature, mild mental retardation, facial, skeletal and renal abnormalities. In addition, ophthalmic examination revealed a keratoconus in the left eye and a right optic disc coloboma. To date, only two cases of Noonan's syndrome with keratoconus have been reported, and this is the second case of this syndrome with optic disc coloboma. To our knowledge, this is the first report of Noonan's syndrome associated with unilateral keratoconus and contralateral optic disc coloboma. In view of the large number of patients with Noonan's syndrome reported to date and the rarity of these ocular abnormalities, it is most likely that this association is fortuitous. Ocular findings reported in patients with Noonan's syndrome are reviewed.

  1. Behavioral Teratogenesis in Drosophila melanogaster.

    Science.gov (United States)

    Mishra, Monalisa; Barik, Bedanta Kumar

    2018-01-01

    Developmental biology is a fascinating branch of science which helps us to understand the mechanism of development, thus the findings are used in various therapeutic approach. Drosophila melanogaster served as a model to find the key molecules that initiate and regulate the mechanism of development. Various genes, transcription factors, and signaling pathways helping in development are identified in Drosophila. Many toxic compounds, which can affect the development, are also recognized using Drosophila model. These compounds, which can affect the development, are named as a teratogen. Many teratogens identified using Drosophila may also act as a teratogen for a human being since 75% of conservation exist between the disease genes present in Drosophila and human. There are certain teratogens, which do not cause developmental defect if exposed during pregnancy, however; behavioral defect appears in later part of development. Such compounds are named as a behavioral teratogen. Thus, it is worthy to identify the potential behavioral teratogen using Drosophila model. Drosophila behavior is well studied in various developmental stages. This chapter describes various methods which can be employed to test behavioral teratogenesis in Drosophila.

  2. Novel isoforms of Dlg are fundamental for neuronal development in Drosophila.

    Science.gov (United States)

    Mendoza, Carolina; Olguín, Patricio; Lafferte, Gabriela; Thomas, Ulrich; Ebitsch, Susanne; Gundelfinger, Eckart D; Kukuljan, Manuel; Sierralta, Jimena

    2003-03-15

    Drosophila discs-large (dlg) mutants exhibit multiple developmental abnormalities, including severe defects in neuronal differentiation and synaptic structure and function. These defects have been ascribed to the loss of a single gene product, Dlg-A, a scaffold protein thought to be expressed in many cell types. Here, we describe that additional isoforms arise as a consequence of different transcription start points and alternative splicing of dlg. At least five different dlg gene products are predicted. We identified a subset of dlg-derived cDNAs that include novel exons encoding a peptide homologous to the N terminus of the mammalian protein SAP97/hDLG (S97N). Dlg isoforms containing the S97N domain are expressed at larval neuromuscular junctions and within the CNS of both embryos and larvae but are not detectable in epithelial tissues. Strong hypomorphic dlg alleles exhibit decreased expression of S97N, which may account for neural-specific aspects of the pleiomorphic dlg mutant phenotype. Selective inhibition of the expression of S97N-containing proteins in embryos by double-strand RNA leads to severe defects in neuronal differentiation and axon guidance, without overt perturbations in epithelia. These results indicate that the differential expression of dlg products correlates with distinct functions in non-neural and neural cells. During embryonic development, proteins that include the S97N domain are essential for proper neuronal differentiation and organization, acting through mechanisms that may include the adequate localization of cell fate determinants.

  3. The Drosophila melanogaster host model

    Science.gov (United States)

    Igboin, Christina O.; Griffen, Ann L.; Leys, Eugene J.

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed. PMID:22368770

  4. The Drosophila melanogaster host model

    Directory of Open Access Journals (Sweden)

    Christina O. Igboin

    2012-02-01

    Full Text Available The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.

  5. The Drosophila melanogaster host model.

    Science.gov (United States)

    Igboin, Christina O; Griffen, Ann L; Leys, Eugene J

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen-host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial-host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis-host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.

  6. Nematocytes: Discovery and characterization of a novel anculeate hemocyte in Drosophila falleni and Drosophila phalerata.

    Directory of Open Access Journals (Sweden)

    Julianna Bozler

    Full Text Available Immune challenges, such as parasitism, can be so pervasive and deleterious that they constitute an existential threat to a species' survival. In response to these ecological pressures, organisms have developed a wide array of novel behavioral, cellular, and molecular adaptations. Research into these immune defenses in model systems has resulted in a revolutionary understanding of evolution and functional biology. As the field has expanded beyond the limited number of model organisms our appreciation of evolutionary innovation and unique biology has widened as well. With this in mind, we have surveyed the hemolymph of several non-model species of Drosophila. Here we identify and describe a novel hemocyte, type-II nematocytes, found in larval stages of numerous Drosophila species. Examined in detail in Drosophila falleni and Drosophila phalerata, we find that these remarkable cells are distinct from previously described hemocytes due to their anucleate state (lacking a nucleus and unusual morphology. Type-II nematocytes are long, narrow cells with spindle-like projections extending from a cell body with high densities of mitochondria and microtubules, and exhibit the ability to synthesize proteins. These properties are unexpected for enucleated cells, and together with our additional characterization, we demonstrate that these type-II nematocytes represent a biological novelty. Surprisingly, despite the absence of a nucleus, we observe through live cell imaging that these cells remain motile with a highly dynamic cellular shape. Furthermore, these cells demonstrate the ability to form multicellular structures, which we suggest may be a component of the innate immune response to macro-parasites. In addition, live cell imaging points to a large nucleated hemocyte, type-I nematocyte, as the progenitor cell, leading to enucleation through a budding or asymmetrical division process rather than nuclear ejection: This study is the first to report such a

  7. Concomitant lower thoracic spine disc disease in lumbar spine MR imaging studies.

    Science.gov (United States)

    Arana, Estanislao; Martí-Bonmatí, Luis; Dosdá, Rosa; Mollá, Enrique

    2002-11-01

    Our objective was to study the coexistence of lower thoracic-spine disc changes in patients with low back pain using a large field of view (FOV) in lumbar spine MR imaging. One hundred fifty patients with low back pain were referred to an MR examination. All patients were studied with a large FOV (27 cm), covering from the coccyx to at least the body of T11. Discs were coded as normal, protrusion, and extrusion (either epiphyseal or intervertebral). The relationship between disc disease and level was established with the Pearson chi(2) test. The T11-12 was the most commonly affected level of the lower thoracic spine with 58 disc cases rated as abnormal. Abnormalities of T11-12 and T12-L1 discs were significantly related only to L1-L2 disease ( p=0.001 and p=0.004, respectively) but unrelated to other disc disease, patient's gender, and age. No correlation was found between other discs. Magnetic resonance imaging of the lumbar spine can detect a great amount of lower thoracic disease, although its clinical significance remains unknown. A statistically significant relation was found within the thoracolumbar junctional region (T11-L2), reflecting common pathoanatomical changes. The absence of relation with lower lumbar spine discs is probably due to differences in their pathomechanisms.

  8. Concomitant lower thoracic spine disc disease in lumbar spine MR imaging studies

    International Nuclear Information System (INIS)

    Arana, Estanislao; Marti-Bonmati, Luis; Dosda, Rosa; Molla, Enrique

    2002-01-01

    Our objective was to study the coexistence of lower thoracic-spine disc changes in patients with low back pain using a large field of view (FOV) in lumbar spine MR imaging. One hundred fifty patients with low back pain were referred to an MR examination. All patients were studied with a large FOV (27 cm), covering from the coccyx to at least the body of T11. Discs were coded as normal, protrusion, and extrusion (either epiphyseal or intervertebral). The relationship between disc disease and level was established with the Pearson χ 2 test. The T11-12 was the most commonly affected level of the lower thoracic spine with 58 disc cases rated as abnormal. Abnormalities of T11-12 and T12-L1 discs were significantly related only to L1-L2 disease (p=0.001 and p=0.004, respectively) but unrelated to other disc disease, patient's gender, and age. No correlation was found between other discs. Magnetic resonance imaging of the lumbar spine can detect a great amount of lower thoracic disease, although its clinical significance remains unknown. A statistically significant relation was found within the thoracolumbar junctional region (T11-L2), reflecting common pathoanatomical changes. The absence of relation with lower lumbar spine discs is probably due to differences in their pathomechanisms. (orig.)

  9. MR imaging findings of a sequestered disc in the lumbar spine: a comparison with an extruded disc

    International Nuclear Information System (INIS)

    Sim, Su Youn; Park, Ji Seon; Ryu, Kyung Nam; Jin, Wook

    2007-01-01

    To compare the MR findings of a sequestered disc with an extruded disc. MR images of 28 patients with a sequestered disc and 18 patients with an extruded disc were retrospectively reviewed. Patients with sequestered discs were divided into two groups whether definite separation from the parent disc was or was not seen. In the latter group (definite separation not seen) and the extruded disc group of patients, the signal intensities of the herniated discs were compared with the signal intensities of the parent discs and were evaluated on T1-and T2-weighted images. We also assessed the presence of a notch within the herniated disc. In the sequestered disc group of patients (28 discs), only 5 discs (18%) showed obvious separation from the parent disc. Among the remaining 23 discs with indefinite separation, the notch was visible in 14 discs (61%) and 9 discs (39%) had no notch. In the extruded disc group (18 discs), the notch was visible in 2 (11%) discs and the difference between the two groups was statistically significant (ρ 0.0002). The signal intensities of the herniated discs on T1-weighted images were isointense in both the sequestered and extruded discs. The difference of incidence of high signal intensities on T2-weighted images was not statistically significant (ρ = 0.125). It is necessary to consider the possibility of the presence of a sequestered disc when a herniated disc material shows a notch

  10. Decapentaplegic and growth control in the developing Drosophila wing.

    Science.gov (United States)

    Akiyama, Takuya; Gibson, Matthew C

    2015-11-19

    As a central model for morphogen action during animal development, the bone morphogenetic protein 2/4 (BMP2/4)-like ligand Decapentaplegic (Dpp) is proposed to form a long-range signalling gradient that directs both growth and pattern formation during Drosophila wing disc development. While the patterning role of Dpp secreted from a stripe of cells along the anterior-posterior compartmental boundary is well established, the mechanism by which a Dpp gradient directs uniform cell proliferation remains controversial and poorly understood. Here, to determine the precise spatiotemporal requirements for Dpp during wing disc development, we use CRISPR-Cas9-mediated genome editing to generate a flippase recognition target (FRT)-dependent conditional null allele. By genetically removing Dpp from its endogenous stripe domain, we confirm the requirement of Dpp for the activation of a downstream phospho-Mothers against dpp (p-Mad) gradient and the regulation of the patterning targets spalt (sal), optomotor blind (omb; also known as bifid) and brinker (brk). Surprisingly, however, third-instar wing blade primordia devoid of compartmental dpp expression maintain relatively normal rates of cell proliferation and exhibit only mild defects in growth. These results indicate that during the latter half of larval development, the Dpp morphogen gradient emanating from the anterior-posterior compartment boundary is not directly required for wing disc growth.

  11. Retina image–based optic disc segmentation

    Directory of Open Access Journals (Sweden)

    Ching-Lin Wang

    2016-05-01

    Full Text Available The change of optic disc can be used to diagnose many eye diseases, such as glaucoma, diabetic retinopathy and macular degeneration. Moreover, retinal blood vessel pattern is unique for human beings even for identical twins. It is a highly stable pattern in biometric identification. Since optic disc is the beginning of the optic nerve and main blood vessels in retina, it can be used as a reference point of identification. Therefore, optic disc segmentation is an important technique for developing a human identity recognition system and eye disease diagnostic system. This article hence presents an optic disc segmentation method to extract the optic disc from a retina image. The experimental results show that the optic disc segmentation method can give impressive results in segmenting the optic disc from a retina image.

  12. Rearing the Fruit Fly Drosophila melanogaster Under Axenic and Gnotobiotic Conditions.

    Science.gov (United States)

    Koyle, Melinda L; Veloz, Madeline; Judd, Alec M; Wong, Adam C-N; Newell, Peter D; Douglas, Angela E; Chaston, John M

    2016-07-30

    The influence of microbes on myriad animal traits and behaviors has been increasingly recognized in recent years. The fruit fly Drosophila melanogaster is a model for understanding microbial interactions with animal hosts, facilitated by approaches to rear large sample sizes of Drosophila under microorganism-free (axenic) conditions, or with defined microbial communities (gnotobiotic). This work outlines a method for collection of Drosophila embryos, hypochlorite dechorionation and sterilization, and transfer to sterile diet. Sterilized embryos are transferred to sterile diet in 50 ml centrifuge tubes, and developing larvae and adults remain free of any exogenous microbes until the vials are opened. Alternatively, flies with a defined microbiota can be reared by inoculating sterile diet and embryos with microbial species of interest. We describe the introduction of 4 bacterial species to establish a representative gnotobiotic microbiota in Drosophila. Finally, we describe approaches for confirming bacterial community composition, including testing if axenic Drosophila remain bacteria-free into adulthood.

  13. A genome-wide gene function prediction resource for Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Han Yan

    2010-08-01

    Full Text Available Predicting gene functions by integrating large-scale biological data remains a challenge for systems biology. Here we present a resource for Drosophila melanogaster gene function predictions. We trained function-specific classifiers to optimize the influence of different biological datasets for each functional category. Our model predicted GO terms and KEGG pathway memberships for Drosophila melanogaster genes with high accuracy, as affirmed by cross-validation, supporting literature evidence, and large-scale RNAi screens. The resulting resource of prioritized associations between Drosophila genes and their potential functions offers a guide for experimental investigations.

  14. The PANDA Endcap Disc DIRC

    Science.gov (United States)

    Föhl, K.; Ali, A.; Belias, A.; Dzhygadlo, R.; Gerhardt, A.; Götzen, K.; Kalicy, G.; Krebs, M.; Lehmann, D.; Nerling, F.; Patsyuk, M.; Peters, K.; Schepers, G.; Schmitt, L.; Schwarz, C.; Schwiening, J.; Traxler, M.; Böhm, M.; Eyrich, W.; Lehmann, A.; Pfaffinger, M.; Uhlig, F.; Düren, M.; Etzelmüller, E.; Hayrapetyan, A.; Kreutzfeld, K.; Merle, O.; Rieke, J.; Schmidt, M.; Wasem, T.; Achenbach, P.; Cardinali, M.; Hoek, M.; Lauth, W.; Schlimme, S.; Sfienti, C.; Thiel, M.

    2018-02-01

    Positively identifying charged kaons in the PANDA forward endcap solid angle range can be achieved with the Endcap Disc DIRC, allowing kaon-pion separation from 1 up to 4 GeV/c with a separation power of at least 3 standard deviations. Design, performance, and components of this DIRC are given, including the recently introduced TOFPET-ASIC based read-out. Results of a prototype operated in a test beam at DESY in 2016 are shown.

  15. The influence of jaw's curvature on the results of the Brazilian disc test

    Directory of Open Access Journals (Sweden)

    Ch.F. Markides

    2016-04-01

    Full Text Available The general contact problem of a disc squeezed between jaws of arbitrary curvature is considered employing Muskhelishvili's complex potentials. Taking advantage of the general solution introduced, the closed-form expressions for the stresses along strategic loci (loaded rim, loaded diameter, disc's center are obtained, in terms of the ratio ρ of the disc's to the jaw's curvature. Then, the effect of ρ (as well as that of the relative stiffness of the disc's and jaw's materials dictating the contact arc on the stress distribution along these loci is explored. It is concluded that, for both smooth contact (zero friction and contact with friction, the role of the jaw's curvature is significant not only along the disc-jaw contact arc (as it could be expected, but also all along the loaded diameter. On the other hand, it is indicated that the stress field at the disc's center is more or less insensitive to the jaw's curvature assuming that ρ lies within the range (0, 0.67 or in other words within the limits defined by the two standardized suggestions, i.e. that of American Society for Testing and Materials (ASTM (plane loading platens with ρ = 0 and that of International Society for Rock Mechanics (ISRM (curved jaws with ρ = 0.67. The upper limit of this range is a kind of compromise between the need to make the stress field at the disc's center independent of the boundary conditions while keeping at the same time the contact angle large enough to reduce the stress concentration and the risk for premature fracture initiation far from the disc's center. For jaws with radius of curvature exceeded by that suggested by ISRM, the stress field at the disc's center is significantly influenced. Especially for jaws with radius approaching that of the disc, the stress field at the disc's center is dramatically distorted rendering Hondros' formula inapplicable and the test results erroneous.

  16. Bioimage Informatics in the context of Drosophila research.

    Science.gov (United States)

    Jug, Florian; Pietzsch, Tobias; Preibisch, Stephan; Tomancak, Pavel

    2014-06-15

    Modern biological research relies heavily on microscopic imaging. The advanced genetic toolkit of Drosophila makes it possible to label molecular and cellular components with unprecedented level of specificity necessitating the application of the most sophisticated imaging technologies. Imaging in Drosophila spans all scales from single molecules to the entire populations of adult organisms, from electron microscopy to live imaging of developmental processes. As the imaging approaches become more complex and ambitious, there is an increasing need for quantitative, computer-mediated image processing and analysis to make sense of the imagery. Bioimage Informatics is an emerging research field that covers all aspects of biological image analysis from data handling, through processing, to quantitative measurements, analysis and data presentation. Some of the most advanced, large scale projects, combining cutting edge imaging with complex bioimage informatics pipelines, are realized in the Drosophila research community. In this review, we discuss the current research in biological image analysis specifically relevant to the type of systems level image datasets that are uniquely available for the Drosophila model system. We focus on how state-of-the-art computer vision algorithms are impacting the ability of Drosophila researchers to analyze biological systems in space and time. We pay particular attention to how these algorithmic advances from computer science are made usable to practicing biologists through open source platforms and how biologists can themselves participate in their further development. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  17. Quiescent gastric stem cells maintain the adult Drosophila stomach.

    Science.gov (United States)

    Strand, Marie; Micchelli, Craig A

    2011-10-25

    The adult Drosophila copper cell region or "stomach" is a highly acidic compartment of the midgut with pH stem cells (GSSCs) produces the acid-secreting copper cells, interstitial cells, and enteroendocrine cells of the stomach. Our assays demonstrate that GSSCs are largely quiescent but can be induced to regenerate the gastric epithelium in response to environmental challenge. Finally, genetic analysis reveals that adult GSSC maintenance depends on Wnt signaling. Characterization of the GSSC lineage in Drosophila, with striking similarities to mammals, will advance the study of both homeostatic and pathogenic processes in the stomach.

  18. Size and density sorting of dust grains in SPH simulations of protoplanetary discs

    Science.gov (United States)

    Pignatale, F. C.; Gonzalez, J.-F.; Cuello, Nicolas; Bourdon, Bernard; Fitoussi, Caroline

    2017-07-01

    The size and density of dust grains determine their response to gas drag in protoplanetary discs. Aerodynamical (size × density) sorting is one of the proposed mechanisms to explain the grain properties and chemical fractionation of chondrites. However, the efficiency of aerodynamical sorting and the location in the disc in which it could occur are still unknown. Although the effects of grain sizes and growth in discs have been widely studied, a simultaneous analysis including dust composition is missing. In this work, we present the dynamical evolution and growth of multicomponent dust in a protoplanetary disc using a 3D, two-fluid (gas+dust) smoothed particle hydrodynamics code. We find that the dust vertical settling is characterized by two phases: a density-driven phase that leads to a vertical chemical sorting of dust and a size-driven phase that enhances the amount of lighter material in the mid-plane. We also see an efficient radial chemical sorting of the dust at large scales. We find that dust particles are aerodynamically sorted in the inner disc. The disc becomes sub-solar in its Fe/Si ratio on the surface since the early stage of evolution but sub-solar Fe/Si can be also found in the outer disc-mid-plane at late stages. Aggregates in the disc mimic the physical and chemical properties of chondrites, suggesting that aerodynamical sorting played an important role in determining their final structure.

  19. Conservatively treated massive prolapsed discs: a 7-year follow-up

    Science.gov (United States)

    Benson, RT; Tavares, SP; Robertson, SC; Sharp, R; Marshall, RW

    2010-01-01

    INTRODUCTION The natural history of a lumbar hernia of the nucleus pulposus (HNP) is not fully known and clear indications for operative intervention cannot be established from the literature. Several studies have shown that the largest discs appear to have the greatest tendency to resolve. The aim of this study was to investigate whether massive prolapsed discs can be safely managed conservatively once clinical improvement has occurred. PATIENTS AND METHODS Thirty-seven patients were studied by clinical assessments and serial magnetic resonance imaging (MRI) over 2 years. Patients had severe sciatica at first, but began to show clinical improvement despite the large disc hernia-tions. Clinical assessment included the Lasegue test and neurological appraisal. The Oswestry Disability Index was used to measure function and changes in function. Serial MRI studies allowed measurement of volume changes of the herniated disc material over a period of time. RESULTS Initial follow-up at an average of 23.2 months revealed that 83% had a complete and sustained recovery at the initial follow-up. Only four patients required a discectomy. The average Oswestry disability index improved from 58% to 15%. Volumetric analysis of serial MRI scans found an average reduction of 64% in disc size. There was a poor correlation between clinical improvement and the extent of disc resolution. CONCLUSIONS A massive disc herniation can pursue a favourable clinical course. If early progress is shown, the long-term prognosis is very good and even massive disc herniations can be treated conservatively. PMID:19887021

  20. Myoblast fusion in Drosophila

    Energy Technology Data Exchange (ETDEWEB)

    Haralalka, Shruti [Stowers Institute for Medical Research, Kansas City, MO 64110 (United States); Abmayr, Susan M., E-mail: sma@stowers.org [Stowers Institute for Medical Research, Kansas City, MO 64110 (United States); Department of Anatomy and Cell Biology, University of Kansas Medical Center, Kansas City, MO 66160 (United States)

    2010-11-01

    The body wall musculature of a Drosophila larva is composed of an intricate pattern of 30 segmentally repeated muscle fibers in each abdominal hemisegment. Each muscle fiber has unique spatial and behavioral characteristics that include its location, orientation, epidermal attachment, size and pattern of innervation. Many, if not all, of these properties are dictated by founder cells, which determine the muscle pattern and seed the fusion process. Myofibers are then derived from fusion between a specific founder cell and several fusion competent myoblasts (FCMs) fusing with as few as 3-5 FCMs in the small muscles on the most ventral side of the embryo and as many as 30 FCMs in the larger muscles on the dorsal side of the embryo. The focus of the present review is the formation of the larval muscles in the developing embryo, summarizing the major issues and players in this process. We have attempted to emphasize experimentally-validated details of the mechanism of myoblast fusion and distinguish these from the theoretically possible details that have not yet been confirmed experimentally. We also direct the interested reader to other recent reviews that discuss myoblast fusion in Drosophila, each with their own perspective on the process . With apologies, we use gene nomenclature as specified by Flybase (http://flybase.org) but provide Table 1 with alternative names and references.

  1. Myoblast fusion in Drosophila

    International Nuclear Information System (INIS)

    Haralalka, Shruti; Abmayr, Susan M.

    2010-01-01

    The body wall musculature of a Drosophila larva is composed of an intricate pattern of 30 segmentally repeated muscle fibers in each abdominal hemisegment. Each muscle fiber has unique spatial and behavioral characteristics that include its location, orientation, epidermal attachment, size and pattern of innervation. Many, if not all, of these properties are dictated by founder cells, which determine the muscle pattern and seed the fusion process. Myofibers are then derived from fusion between a specific founder cell and several fusion competent myoblasts (FCMs) fusing with as few as 3-5 FCMs in the small muscles on the most ventral side of the embryo and as many as 30 FCMs in the larger muscles on the dorsal side of the embryo. The focus of the present review is the formation of the larval muscles in the developing embryo, summarizing the major issues and players in this process. We have attempted to emphasize experimentally-validated details of the mechanism of myoblast fusion and distinguish these from the theoretically possible details that have not yet been confirmed experimentally. We also direct the interested reader to other recent reviews that discuss myoblast fusion in Drosophila, each with their own perspective on the process . With apologies, we use gene nomenclature as specified by Flybase (http://flybase.org) but provide Table 1 with alternative names and references.

  2. Role of Scrib and Dlg in anterior-posterior patterning of the follicular epithelium during Drosophila oogenesis

    Directory of Open Access Journals (Sweden)

    Yu Lingzhu

    2009-12-01

    Full Text Available Abstract Background Proper patterning of the follicle cell epithelium over the egg chamber is essential for the Drosophila egg development. Differentiation of the epithelium into several distinct cell types along the anterior-posterior axis requires coordinated activities of multiple signaling pathways. Previously, we reported that lethal(2giant larvae (lgl, a Drosophila tumor suppressor gene, is required in the follicle cells for the posterior follicle cell (PFC fate induction at mid-oogenesis. Here we explore the role of another two tumor suppressor genes, scribble (scrib and discs large (dlg, in the epithelial patterning. Results We found that removal of scrib or dlg function from the follicle cells at posterior terminal of the egg chamber causes a complete loss of the PFC fate. Aberrant specification and differentiation of the PFCs in the mosaic clones can be ascribed to defects in coordinated activation of the EGFR, JAK and Notch signaling pathways in the multilayered cells. Meanwhile, the clonal analysis revealed that loss-of-function mutations in scrib/dlg at the anterior domains result in a partially penetrant phenotype of defective induction of the stretched and centripetal cell fate, whereas specification of the border cell fate can still occur in the most anterior region of the mutant clones. Further, we showed that scrib genetically interacts with dlg in regulating posterior patterning of the epithelium. Conclusion In this study we provide evidence that scrib and dlg function differentially in anterior and posterior patterning of the follicular epithelium at oogenesis. Further genetic analysis indicates that scrib and dlg act in a common pathway to regulate PFC fate induction. This study may open another window for elucidating role of scrib/dlg in controlling epithelial polarity and cell proliferation during development.

  3. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    OpenAIRE

    Ram Prakash Gupta; Anjali Bajpai; Pradip Sinha

    2017-01-01

    During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Ey...

  4. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    OpenAIRE

    Gupta, Ram Prakash; Bajpai, Anjali; Sinha, Pradip

    2017-01-01

    ABSTRACT During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field sel...

  5. [Research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration].

    Science.gov (United States)

    Liang, Hang; Deng, Xiangyu; Shao, Zengwu

    2017-10-01

    To summarize the research progress of intervertebral disc endogenous stem cells for intervertebral disc regeneration and deduce the therapeutic potential of endogenous repair for intervertebral disc degeneration. The original articles about intervertebral disc endogenous stem cells for intervertebral disc regeneration were extensively reviewed; the reparative potential in vivo and the extraction and identification in vitro of intervertebral disc endogenous stem cells were analyzed; the prospect of endogenous stem cells for intervertebral disc regeneration was predicted. Stem cell niche present in the intervertebral discs, from which stem cells migrate to injured tissues and contribute to tissues regeneration under certain specific microenvironment. Moreover, the migration of stem cells is regulated by chemokines system. Tissue specific progenitor cells have been identified and successfully extracted and isolated. The findings provide the basis for biological therapy of intervertebral disc endogenous stem cells. Intervertebral disc endogenous stem cells play a crucial role in intervertebral disc regeneration. Therapeutic strategy of intervertebral disc endogenous stem cells is proven to be a promising biological approach for intervertebral disc regeneration.

  6. Biomaterials for intervertebral disc regeneration and repair.

    Science.gov (United States)

    Bowles, Robert D; Setton, Lori A

    2017-06-01

    The intervertebral disc contributes to motion, weight bearing, and flexibility of the spine, but is susceptible to damage and morphological changes that contribute to pathology with age and injury. Engineering strategies that rely upon synthetic materials or composite implants that do not interface with the biological components of the disc have not met with widespread use or desirable outcomes in the treatment of intervertebral disc pathology. Here we review bioengineering advances to treat disc disorders, using cell-supplemented materials, or acellular, biologically based materials, that provide opportunity for cell-material interactions and remodeling in the treatment of intervertebral disc disorders. While a field still in early development, bioengineering-based strategies employing novel biomaterials are emerging as promising alternatives for clinical treatment of intervertebral disc disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Development of rupture discs for the FBTR

    International Nuclear Information System (INIS)

    Chetal, S.C.; Raju, C.; Anandkumar, V.; Seetharaman, V.; Rajan, K.K.

    1984-01-01

    Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. Reverse buckling knife blade concept with austenitic stainless steel disc has been developed for the rupture disc assemblies required for Fast Breeder Test Reactor (FBTR). Hydroforming process without any die has been used for disc fabrication. One rupture disc assembly required for steam generator is undergoing sodium endurance test and has accumulated 4,500 hours. The present status of development work as demonstrated by room temperature experimental results as well as the scope for future work are discussed. (author)

  8. Evolutionary genetics: the Drosophila model

    Indian Academy of Sciences (India)

    Unknown

    Evolutionary genetics straddles the two fundamental processes of life, ... of the genus Drosophila have been used extensively as model systems in experimental ... issue will prove interesting, informative and thought-provoking for both estab-.

  9. Anterolateral Approach for Central Thoracic Disc Prolapse-Surgical Strategies Used to Tackle Differing Operative Findings: 3-Dimensional Operative Video.

    Science.gov (United States)

    Patel, Krunal; Budohoski, Karol P; Kenyon, Olivia R P; Barone, Damiano G; Santarius, Thomas; Kirollos, Ramez W; Mannion, Richard J; Trivedi, Rikin A

    2018-04-02

    Thoracic disc prolapses causing cord compression can be challenging. For compressive central disc protrusions, a posterior approach is not suitable due to an unacceptable level of cord manipulation. An anterolateral transthoracic approach provides direct access to the disc prolapse allowing for decompression without disturbing the spinal cord. In this video, we describe 2 cases of thoracic myelopathy from a compressive central thoracic disc prolapse. In both cases, informed consent was obtained. Despite similar radiological appearances of heavy calcification, intraoperatively significant differences can be encountered. We demonstrate different surgical strategies depending on the consistency of the disc and the adherence to the thecal sac. With adequate exposure and detachment from adjacent vertebral bodies, soft discs can be, in most instances, separated from the theca with minimal cord manipulation. On the other hand, largely calcified discs often present a significantly greater challenge and require thinning the disc capsule before removal. In cases with significant adherence to dura, in order to prevent cord injury or cerebrospinal fluid leak a thinned shell can be left, providing total detachment from adjacent vertebrae can be achieved. Postoperatively, the first patient, with a significantly calcified disc, developed a transient left leg weakness which recovered by 3-month follow-up. This video outlines the anatomical considerations and operative steps for a transthoracic approach to a central disc prolapse, whilst demonstrating that computed tomography appearances are not always indicative of potential operative difficulties.

  10. Expression of Genes Involved in Drosophila Wing Morphogenesis and Vein Patterning Are Altered by Spaceflight

    Science.gov (United States)

    Parsons-Wingerter, Patricia A.; Hosamani, Ravikumar; Bhattacharya, Sharmila

    2015-01-01

    Imaginal wing discs of Drosophila melanogaster (fruit fly) defined during embryogenesis ultimately result in mature wings of stereotyped (specific) venation patterning. Major regulators of wing disc development are the epidermal growth factor receptor (EGF), Notch, Hedgehog (Hh), Wingless (Wg), and Dpp signaling pathways. Highly stereotyped vascular patterning is also characteristic of tissues in other organisms flown in space such as the mouse retina and leaves of Arabidopsis thaliana. Genetic and other adaptations of vascular patterning to space environmental factors have not yet been systematically quantified, despite widespread recognition of their critical importance for terrestrial and microgravity applications. Here we report changes in gene expression with space flight related to Drosophila wing morphogenesis and vein patterning. In addition, genetically modified phenotypes of increasingly abnormal ectopic wing venation in the Drosophila wing1 were analyzed by NASA's VESsel GENeration Analysis (VESGEN) software2. Our goal is to further develop insightful vascular mappings associated with bioinformatic dimensions of genetic or other molecular phenotypes for correlation with genetic and other molecular profiling relevant to NASA's GeneLab and other Space Biology exploration initiatives.

  11. Multiple Arginine Residues Are Methylated in Drosophila Mre11 and Required for Survival Following Ionizing Radiation.

    Science.gov (United States)

    Yuan, Qing; Tian, Ran; Zhao, Haiying; Li, Lijuan; Bi, Xiaolin

    2018-05-31

    Mre11 is a key player for DNA double strand break repair. Previous studies have shown that mammalian Mre11 is methylated at multiple arginines in its C-terminal Glycine-Arginine-Rich motif (GAR) by protein arginine methyltransferase PRMT1. Here, we found that the Drosophila Mre11 is methylated at arginines 559, 563, 565, and 569 in the GAR motif by DART1, the Drosophila homolog of PRMT1. Mre11 interacts with DART1 in S2 cells, and this interaction does not require the GAR motif. Arginines methylated Mre11 localizes exclusively in the nucleus as soluble nuclear protein or chromatin-binding protein. To study the in vivo functions of methylation, we generated the single Arg-Ala and all Arginines mutated flies. We found these mutants were sensitive to ionizing radiation. Furthermore, Arg-Ala mutated flies had no irradiation induced G2/M checkpoint defect in wing disc and eye disc. Thus, we provided evidence that arginines in Drosophila Mre11 are methylated by DART1 methytransferase and flies loss of arginine methylation are sensitive to irradiation. Copyright © 2018 Yuan et al.

  12. Physiological pattern of lumbar disc height

    International Nuclear Information System (INIS)

    Biggemann, M.; Frobin, W.; Brinckmann, P.

    1997-01-01

    Purpose of this study is to present a new method of quantifying objectively the height of all discs in lateral radiographs of the lumbar spine and of analysing the normal craniocaudal sequence pattern of lumbar disc heights. Methods: The new parameter is the ventrally measured disc height corrected for the dependence on the angle of lordosis by normalisation to mean angles observed in the erect posture of healthy persons. To eliminate radiographic magnification, the corrected ventral height is related to the mean depth of the cranially adjoining vertebra. In this manner lumbar disc heights were objectively measured in young, mature and healthy persons (146 males and 65 females). The craniocaudal sequence pattern was analysed by mean values from all persons and by height differences of adjoining discs in each individual lumbar spine. Results: Mean normative values demonstrated an increase in disc height between L1/L2 and L4/L5 and a constant or decreasing disc height between L4/L5 and L5/S1. However, this 'physiological sequence of disc height in the statistical mean' was observed in only 36% of normal males and 55% of normal females. Conclusion: The radiological pattern of the 'physiological sequence of lumbar disc height' leads to a relevant portion of false positive pathological results especially at L4/L5. An increase of disc height from L4/L5 to L5/S1 may be normal. The recognition of decreased disc height should be based on an abrupt change in the heights of adjoining discs and not on a deviation from a craniocaudal sequence pattern. (orig.) [de

  13. Resources for Functional Genomics Studies in Drosophila melanogaster

    Science.gov (United States)

    Mohr, Stephanie E.; Hu, Yanhui; Kim, Kevin; Housden, Benjamin E.; Perrimon, Norbert

    2014-01-01

    Drosophila melanogaster has become a system of choice for functional genomic studies. Many resources, including online databases and software tools, are now available to support design or identification of relevant fly stocks and reagents or analysis and mining of existing functional genomic, transcriptomic, proteomic, etc. datasets. These include large community collections of fly stocks and plasmid clones, “meta” information sites like FlyBase and FlyMine, and an increasing number of more specialized reagents, databases, and online tools. Here, we introduce key resources useful to plan large-scale functional genomics studies in Drosophila and to analyze, integrate, and mine the results of those studies in ways that facilitate identification of highest-confidence results and generation of new hypotheses. We also discuss ways in which existing resources can be used and might be improved and suggest a few areas of future development that would further support large- and small-scale studies in Drosophila and facilitate use of Drosophila information by the research community more generally. PMID:24653003

  14. Debris disc constraints on planetesimal formation

    Science.gov (United States)

    Krivov, Alexander V.; Ide, Aljoscha; Löhne, Torsten; Johansen, Anders; Blum, Jürgen

    2018-02-01

    Two basic routes for planetesimal formation have been proposed over the last decades. One is a classical `slow-growth' scenario. Another one is particle concentration models, in which small pebbles are concentrated locally and then collapse gravitationally to form planetesimals. Both types of models make certain predictions for the size spectrum and internal structure of newly born planetesimals. We use these predictions as input to simulate collisional evolution of debris discs left after the gas dispersal. The debris disc emission as a function of a system's age computed in these simulations is compared with several Spitzer and Herschel debris disc surveys around A-type stars. We confirm that the observed brightness evolution for the majority of discs can be reproduced by classical models. Further, we find that it is equally consistent with the size distribution of planetesimals predicted by particle concentration models - provided the objects are loosely bound `pebble piles' as these models also predict. Regardless of the assumed planetesimal formation mechanism, explaining the brightest debris discs in the samples uncovers a `disc mass problem'. To reproduce such discs by collisional simulations, a total mass of planetesimals of up to ˜1000 Earth masses is required, which exceeds the total mass of solids available in the protoplanetary progenitors of debris discs. This may indicate that stirring was delayed in some of the bright discs, that giant impacts occurred recently in some of them, that some systems may be younger than previously thought or that non-collisional processes contribute significantly to the dust production.

  15. Gd-DTPA-enhanced MR in thoracic disc herniations

    International Nuclear Information System (INIS)

    Parizel, P.M.; Rodesch, G.; Baleriaux, D.; Segebarth, C.; Zegers de Beyl, D.; Haens, J. d'; Noterman, J.

    1989-01-01

    The Gd-DTPA-enhanced magnetic resonance findings in two patients with herniated thoracic intervertebral discs are reported. The first patient was a 56-year-old woman with a small subligamentous T6-7 disc herniation, slightly lateralized to the right. The second patient was a 51-year-old man with a central and right posterolateral disc herniation, including a large calcified fragment, at the T8-9 level. The nonenhanced MR examination revealed the presence of an extradural mass lesion in both patients, impinging upon the dural sac and compressing and displacing the spinal cord posteriorly. The lesion was slightly hypointense on both T1- and T2-weighted spin echo sequences. Following intravenous injection of Gd-DTPA in a dosage of 0.1 mmol/kg body weight, enhancement of the posterior longitudinal ligament was noted and triangular areas of contrast uptake were seen to occur in the epidural space above and below the herniated disc. At surgery, they were found to correspond to dilated and congested epidural veins. (orig.)

  16. Bars in dark-matter-dominated dwarf galaxy discs

    Science.gov (United States)

    Marasco, A.; Oman, K. A.; Navarro, J. F.; Frenk, C. S.; Oosterloo, T.

    2018-05-01

    We study the shape and kinematics of simulated dwarf galaxy discs in the APOSTLE suite of Λ cold dark matter (ΛCDM) cosmological hydrodynamical simulations. We find that a large fraction of these gas-rich, star-forming discs show weak bars in their stellar component, despite being dark-matter-dominated systems. The bar pattern shape and orientation reflect the ellipticity of the dark matter potential, and its rotation is locked to the slow figure rotation of the triaxial dark halo. The bar-like nature of the potential induces non-circular motions in the gas component, including strong bisymmetric flows that can be readily seen as m = 3 harmonic perturbations in the H I line-of-sight velocity fields. Similar bisymmetric flows are seen in many galaxies of The HI Nearby Galaxy Survey (THINGS) and Local Irregulars That Trace Luminosity Extremes THINGS (LITTLE THINGS), although on average their amplitudes are a factor of ˜2 weaker than in our simulated discs. Our results indicate that bar-like patterns may arise even when baryons are not dominant, and that they are common enough to warrant careful consideration when analysing the gas kinematics of dwarf galaxy discs.

  17. Sex chromosomes and speciation in Drosophila

    Science.gov (United States)

    Presgraves, Daven C.

    2010-01-01

    Two empirical rules suggest that sex chromosomes play a special role in speciation. The first is Haldane's rule— the preferential sterility and inviability of species hybrids of the heterogametic (XY) sex. The second is the disproportionately large effect of the X chromosome in genetic analyses of hybrid sterility. Whereas the causes of Haldane's rule are well established, the causes of the ‘large X-effect’ have remained controversial. New genetic analyses in Drosophila confirm that the X is a hotspot for hybrid male sterility factors, providing a proximate explanation for the large X-effect. Several other new findings— on faster X evolution, X chromosome meiotic drive, and the regulation of the X chromosome in the male-germline— provide plausible evolutionary explanations for the large X-effect. PMID:18514967

  18. A novel Drosophila Girdin-like protein is involved in Akt pathway control of cell size

    Energy Technology Data Exchange (ETDEWEB)

    Puseenam, Aekkachai [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Yoshioka, Yasuhide [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Venture Laboratory, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Nagai, Rika [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Hashimoto, Reina [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Venture Laboratory, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Suyari, Osamu [Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Itoh, Masanobu [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Enomoto, Atsushi [Department of Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi 466-8550 (Japan); Takahashi, Masahide [Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Department of Pathology, Center for Neurological Disease and Cancer, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi 466-8550 (Japan); Yamaguchi, Masamitsu, E-mail: myamaguc@kit.ac.jp [Department of Applied Biology, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan); Insect Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Kyoto 606-8585 (Japan)

    2009-11-15

    The Akt signaling pathway is well known to regulate cell proliferation and growth. Girdin, a novel substrate of Akt, plays a crucial role in organization of the actin cytoskeleton and cell motility under the control of Akt. We here identified a novel Girdin-like protein in Drosophila (dGirdin), which has two isoforms, dGirdin PA and dGirdin PB. dGirdin shows high homology with human Girdin in the N-terminal and coiled-coil domains, while diverging at the C-terminal domain. On establishment of transgenic fly lines, featuring knockdown or overexpression of dGirdin in vivo, overexpression in the wing disc cells induced ectopic apoptosis, implying a role in directing apoptosis. Knockdown of dGirdin in the Drosophila wing imaginal disc cells resulted in reduction of cell size. Furthermore, this was enhanced by half reduction of the Akt gene dose, suggesting that Akt positively regulates dGirdin. In the wing disc, cells in which dGirdin was knocked down exhibited disruption of actin filaments. From these in vivo analyses, we conclude that dGirdin is required for actin organization and regulation of appropriate cell size under control of the Akt signaling pathway.

  19. A novel Drosophila Girdin-like protein is involved in Akt pathway control of cell size

    International Nuclear Information System (INIS)

    Puseenam, Aekkachai; Yoshioka, Yasuhide; Nagai, Rika; Hashimoto, Reina; Suyari, Osamu; Itoh, Masanobu; Enomoto, Atsushi; Takahashi, Masahide; Yamaguchi, Masamitsu

    2009-01-01

    The Akt signaling pathway is well known to regulate cell proliferation and growth. Girdin, a novel substrate of Akt, plays a crucial role in organization of the actin cytoskeleton and cell motility under the control of Akt. We here identified a novel Girdin-like protein in Drosophila (dGirdin), which has two isoforms, dGirdin PA and dGirdin PB. dGirdin shows high homology with human Girdin in the N-terminal and coiled-coil domains, while diverging at the C-terminal domain. On establishment of transgenic fly lines, featuring knockdown or overexpression of dGirdin in vivo, overexpression in the wing disc cells induced ectopic apoptosis, implying a role in directing apoptosis. Knockdown of dGirdin in the Drosophila wing imaginal disc cells resulted in reduction of cell size. Furthermore, this was enhanced by half reduction of the Akt gene dose, suggesting that Akt positively regulates dGirdin. In the wing disc, cells in which dGirdin was knocked down exhibited disruption of actin filaments. From these in vivo analyses, we conclude that dGirdin is required for actin organization and regulation of appropriate cell size under control of the Akt signaling pathway.

  20. Upper thoracic-spine disc degeneration in patients with cervical pain.

    Science.gov (United States)

    Arana, Estanislao; Martí-Bonmatí, Luis; Mollá, Enrique; Costa, Salvador

    2004-01-01

    To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6 +/- 14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P < 0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated ( P = 0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together ( P < 0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms.

  1. Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Christe, A.; Vock, P. [University of Berne, Department of Radiology, Inselspital, Berne (Switzerland); Laeubli, R.; Berlemann, U. [University of Berne, Department of Orthopaedic Surgery, Inselspital, Berne (Switzerland); Guzman, R.; Schroth, G. [University of Berne, Department of Neuroradiology, Inselspital, Berne (Switzerland); Moore, R.J. [Institute of Medical and Veterinary Science, Adelaide (Australia); Loevblad, K.O. [University of Berne, Department of Neuroradiology, Inselspital, Berne (Switzerland); Geneva University Hospital, Neuroradiology SRRI, Geneva 14 (Switzerland)

    2005-10-01

    Decisions about the treatment of neck pain are largely made on the basis of information gained from plain X-rays and magnetic resonance imaging (MRI), which are used routinely as part of preliminary investigation. We performed a descriptive cadaveric study to compare histology with radiography and MRI. We correlated plain radiography, disc height [Farfan index (FI)] and MRI findings with histology to assess the ability of radiology to detect significant pathologic lesions. The study included 52 motion segments from nine subjects over the age of 50, who underwent routine hospital autopsy. Disc degeneration was assessed by histology, radiography, disc height (FI: anterior disc height plus posterior disc height divided by anterioposterior diameter) and MRI using established grading systems. Most of the discs were classified radiologically as grade 1 (19/52), grade 2 (13/52), grade 3 (9/52) or grade 4 (3/52). Eight of the discs were graded as normal. The distribution of MRI grades was grade 0 (9/36), grade 1 (9/36), grade 2 (7/36), grade 3 (8/36) and grade 4 (3/36). Half of the discs (26/52) showed advanced (grade 4) degeneration histologically. FI correlated with histological grade (P=0.013), MRI grade (P=0.02) and radiological grade (P<0.001) of degeneration. Radiological and histological grade of degeneration showed a weak correlation (r=0.3, P=0.033). MRI correlated with overall histological grade (r=0.41, P=0.015, n=34). Histological features (e.g., tears, rim lesions, prolapse of nucleus material) were poorly recognised by MRI, which had a sensitivity for disc material prolapse and annulus tears of less than 40%. Our study showed that discs from patients over 50 years are histologically severely degenerated; however, these changes may not be detected by conventional radiography and MRI. (orig.)

  2. Upper thoracic-spine disc degeneration in patients with cervical pain

    Energy Technology Data Exchange (ETDEWEB)

    Arana, Estanislao; Marti-Bonmati, Luis; Costa, Salvador [Department of Radiology, Clinica Quiron, Avda Blasco Ibanez 14, 46010, Valencia (Spain); Molla, Enrique [Department of Radiology, Clinica Quiron, Avda Blasco Ibanez 14, 46010, Valencia (Spain); Department of Morphological Sciences, University of Valencia, Valencia (Spain)

    2004-01-01

    To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6{+-}14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P<0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated (P=0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together (P<0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms. (orig.)

  3. Wear analysis of disc cutters of full face rock tunnel boring machine

    Science.gov (United States)

    Zhang, Zhaohuang; Meng, Liang; Sun, Fei

    2014-11-01

    Wear is a major factor of disc cutters' failure. No current theory offers a standard for the prediction of disc cutter wear yet. In the field the wear prediction method commonly used is based on the excavation length of tunnel boring machine(TBM) to predict the disc cutter wear and its wear law, considering the location number of each disc cutter on the cutterhead(radius for installation); in theory, there is a prediction method of using arc wear coefficient. However, the preceding two methods have their own errors, with their accuracy being 40% or so and largely relying on the technicians' experience. Therefore, radial wear coefficient, axial wear coefficient and trajectory wear coefficient are defined on the basis of the operating characteristics of TBM. With reference to the installation and characteristics of disc cutters, those coefficients are modified according to penetration, which gives rise to the presentation of comprehensive axial wear coefficient, comprehensive radial wear coefficient and comprehensive trajectory wear coefficient. Calculation and determination of wear coefficients are made with consideration of data from a segment of TBM project(excavation length 173 m). The resulting wear coefficient values, after modification, are adopted to predict the disc cutter wear in the follow-up segment of the TBM project(excavation length of 5621 m). The prediction results show that the disc cutter wear predicted with comprehensive radial wear coefficient and comprehensive trajectory wear coefficient are not only accurate(accuracy 16.12%) but also highly congruous, whereas there is a larger deviation in the prediction with comprehensive axial wear coefficient(accuracy 41%, which is in agreement with the prediction of disc cutters' life in the field). This paper puts forth a new method concerning prediction of life span and wear of TBM disc cutters as well as timing for replacing disc cutters.

  4. Degeneration of the cervical disc: histology compared with radiography and magnetic resonance imaging

    International Nuclear Information System (INIS)

    Christe, A.; Vock, P.; Laeubli, R.; Berlemann, U.; Guzman, R.; Schroth, G.; Moore, R.J.; Loevblad, K.O.

    2005-01-01

    Decisions about the treatment of neck pain are largely made on the basis of information gained from plain X-rays and magnetic resonance imaging (MRI), which are used routinely as part of preliminary investigation. We performed a descriptive cadaveric study to compare histology with radiography and MRI. We correlated plain radiography, disc height [Farfan index (FI)] and MRI findings with histology to assess the ability of radiology to detect significant pathologic lesions. The study included 52 motion segments from nine subjects over the age of 50, who underwent routine hospital autopsy. Disc degeneration was assessed by histology, radiography, disc height (FI: anterior disc height plus posterior disc height divided by anterioposterior diameter) and MRI using established grading systems. Most of the discs were classified radiologically as grade 1 (19/52), grade 2 (13/52), grade 3 (9/52) or grade 4 (3/52). Eight of the discs were graded as normal. The distribution of MRI grades was grade 0 (9/36), grade 1 (9/36), grade 2 (7/36), grade 3 (8/36) and grade 4 (3/36). Half of the discs (26/52) showed advanced (grade 4) degeneration histologically. FI correlated with histological grade (P=0.013), MRI grade (P=0.02) and radiological grade (P<0.001) of degeneration. Radiological and histological grade of degeneration showed a weak correlation (r=0.3, P=0.033). MRI correlated with overall histological grade (r=0.41, P=0.015, n=34). Histological features (e.g., tears, rim lesions, prolapse of nucleus material) were poorly recognised by MRI, which had a sensitivity for disc material prolapse and annulus tears of less than 40%. Our study showed that discs from patients over 50 years are histologically severely degenerated; however, these changes may not be detected by conventional radiography and MRI. (orig.)

  5. Upper thoracic-spine disc degeneration in patients with cervical pain

    International Nuclear Information System (INIS)

    Arana, Estanislao; Marti-Bonmati, Luis; Costa, Salvador; Molla, Enrique

    2004-01-01

    To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established. One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6±14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion. Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affected level of the upper thoracic spine, with 15 bulge/protrusions and one extrusion. Upper degenerative thoracic disc contour changes presented in older patients than the cervical levels (Student-Newman-Keuls test, P<0.001). Degenerative disc contour changes at the C7-T1, T1-2, T2-3 and T3-4 levels were significantly correlated (P=0.001), but unrelated to any other disc disease, patient's gender or age. Degenerative cervical disc disease was closely related together (P<0.001), but not with any thoracic disc. A statistically significant relation was found within the upper thoracic discs, reflecting common pathoanatomical changes. The absence of relation to cervical segments is probably due to differences in their pathomechanisms. (orig.)

  6. Genetic changeover in Drosophila populations

    International Nuclear Information System (INIS)

    Wallace, B.

    1986-01-01

    Three populations of Drosophila melanogaster that were daughter populations of two others with histories of high, continuous radiation exposure [population 5 (irradiated, small population size) gave rise to populations 17 (small) and 18 (large); population 6 (irradiated, large population size) gave rise to population 19 (large)] were maintained for 1 year with no radiation exposure. The frequency with which random combinations of second chromosomes taken from population 19 proved to be lethal changed abruptly after about 8 months, thus revealing the origin of a selectively favored element in that population. (This element may or may not have been the cause of the lethality.) A comparison of the loss of lethals in populations 17 and 18 with a loss that occurred concurrently in the still-irradiated population 5 suggests that a second, selectively favored element had arisen in that population just before populations 17 and 18 were split off. This element was on a nonlethal chromosome. The result in population 5 was the elimination of many lethals from that population, followed by a subsequent increase as mutations occurred in the favored nonlethal chromosome. Populations 17 and 18, with no radiation exposure, underwent a loss of lethals with no subsequent increase. The events described here, as well as others to be described elsewhere, suggest that populations may be subject to episodic periods of rapid gene frequency changes that occur under intense selection pressure. In the instances in which the changeover was revealed by the elimination of preexisting lethals, earlier lethal frequencies were reduced by approximately one-half; the selectively favored elements appear, then, to be favored in the heterozygous--not homozygous--condition

  7. Force characteristics of solenoid electromagnet with ferromagnetic disc in the coil

    International Nuclear Information System (INIS)

    Gueorgiev, Vultchan; Yatchev, Ivan; Alexandrov, Alexander

    2002-01-01

    The paper presents the construction and characteristics of a solenoid electromagnet with ferromagnetic disc placed in the coil. The presence if the disc leads to change of the force characteristic compared with conventional solenoid electromagnets - increasing the force at large air gaps and decreasing the force at small air gaps. This could be very useful for some actuators. It has been studied how the force characteristic depend on disc size, position and material. Finite element method has been used for field and force calculations of the electromagnet. (Author)

  8. Intradiscal injection of simvastatin results in radiologic, histologic, and genetic evidence of disc regeneration in a rat model of degenerative disc disease

    Science.gov (United States)

    Than, Khoi D.; Rahman, Shayan U.; Wang, Lin; Khan, Adam; Kyere, Kwaku A.; Than, Tracey T.; Miyata, Yoshinari; Park, Yoon-Shin; La Marca, Frank; Kim, Hyungjin M.; Zhang, Huina; Park, Paul; Lin, Chia-Ying

    2014-01-01

    BACKGROUND CONTEXT A large percentage of back pain can be attributed to degeneration of the intervertebral disc (IVD). Bone morphogenetic protein-2 (BMP-2) is known to play an important role in chondrogenesis of the IVD. Simvastatin is known to up-regulate expression of BMP-2. Thus, we hypothesized that intradiscal injection of simvastatin in a rat model of degenerative disc disease (DDD) would result in retardation of DDD. PURPOSE To develop a novel conservative treatment for DDD and related discogenic back pain. STUDY DESIGN/SETTING Laboratory investigation. METHODS Disc injury was induced in 272 rats via 21-gauge needle puncture. After 6 weeks, injured discs were treated with simvastatin in a saline or hydrogel carrier. Rats were sacrificed at predetermined time points. Outcome measures assessed were radiologic, histologic, and genetic. Radiologically, the MRI index (number of pixels multiplied by corresponding image densities) was determined. Histologically, disc spaces were read by 3 blinded scorers employing a previously described histological grading scale. Genetically, nuclei pulposi were harvested and polymerase chain reaction was run to determine relative levels of aggrecan, collagen type II, and BMP-2 gene expression. This project was supported by Grant No. R01 AR056649 from NIAMS/NIH. There are no other financial conflicts of interest to report. RESULTS Radiologically, discs treated with 5 mg/mL simvastatin in hydrogel or saline demonstrated MRI indices that were normal through 8 weeks post-treatment, although this was more sustained when delivered in hydrogel. Histologically, discs treated with 5 mg/mL simvastatin in hydrogel demonstrated improved grades in comparison to discs treated at higher doses. Genetically, discs treated with 5 mg/mL of simvastatin in hydrogel demonstrated higher gene expression of aggrecan and collagen type II than control. CONCLUSIONS Degenerate discs treated with 5 mg/mL simvastatin in a hydrogel carrier demonstrated

  9. Local models of astrophysical discs

    Science.gov (United States)

    Latter, Henrik N.; Papaloizou, John

    2017-12-01

    Local models of gaseous accretion discs have been successfully employed for decades to describe an assortment of small-scale phenomena, from instabilities and turbulence, to dust dynamics and planet formation. For the most part, they have been derived in a physically motivated but essentially ad hoc fashion, with some of the mathematical assumptions never made explicit nor checked for consistency. This approach is susceptible to error, and it is easy to derive local models that support spurious instabilities or fail to conserve key quantities. In this paper we present rigorous derivations, based on an asympototic ordering, and formulate a hierarchy of local models (incompressible, Boussinesq and compressible), making clear which is best suited for a particular flow or phenomenon, while spelling out explicitly the assumptions and approximations of each. We also discuss the merits of the anelastic approximation, emphasizing that anelastic systems struggle to conserve energy unless strong restrictions are imposed on the flow. The problems encountered by the anelastic approximation are exacerbated by the disc's differential rotation, but also attend non-rotating systems such as stellar interiors. We conclude with a defence of local models and their continued utility in astrophysical research.

  10. Optic Disc Drusen in Children

    DEFF Research Database (Denmark)

    Malmqvist, Lasse; Li, Xiao Qiang; Eckmann, Christina L

    2017-01-01

    diameter and fetal birth and pubertal parameters are associated with the presence of ODD. METHODS: This observational, longitudinal population-based birth cohort study, with a nested case-control, included 1,406 children. Eye examinations were performed when the children were between 11 and 12 years of age....... Assessment was performed of optical coherence tomography (OCT) scans from 1,304 children with gradable enhanced depth imaging scans of the optic disc. RESULTS: ODD in one or both eyes were found in 13 (1.0%) of all children. All but one of the cases were found in children with scleral canal diameter...... in the lowest quartile (1,182-1,399 μm) in the nested case-control study. Children with ODD had a mean disc diameter of 1,339 μm (interquartile range, 30 μm), whereas it was 1,508 μm (interquartile range, 196 μm) in the 130 controls without ODD (P

  11. Cervical disc herniation manifesting as a Brown-Sequard syndrome

    Directory of Open Access Journals (Sweden)

    Kunio Yokoyama

    2012-01-01

    Full Text Available Brown-Sequard syndrome is commonly seen in the setting of spinal trauma or an extramedullary spinal neoplasm. The clinical picture reflects hemisection of the spinal cord. We report a rare case of Brown-Sequard syndrome caused by a large cervical herniated disc. A 63-year-old man presented with progressive right hemiparesis and disruption of pain and temperature sensation on the left side of the body. Magnetic resonance imaging showed large C3-C4 disc herniation compressing the spinal cord at that level, with severe canal stenosis from C4 through C7. Decompressive cervical laminoplasty was performed. After surgery, complete sensory function was restored and a marked improvement in motor power was obtained.

  12. Hermann Muller and Mutations in Drosophila

    Science.gov (United States)

    dropdown arrow Site Map A-Z Index Menu Synopsis Hermann Muller and Mutations in Drosophila Resources with University of Texas. In Austin his experiments on fruit flies (Drosophila) first showed that exposure to September to spend a year at the only Drosophila laboratory in Europe which was doing parallel work

  13. Use of Drosophila to study DNA repair

    International Nuclear Information System (INIS)

    Boyd, J.B.; Harris, P.V.; Sakaguchi, K.

    1988-01-01

    This paper discusses Drosophila, the premier metazoan organism for analyzing many fundamental features of eukaryotic gene regulation. The authors present adaptations of several approaches for studying DNA repair to an analysis of repair-defective mutants in Drosophila. A current understanding of Drosophila DNA repair is described

  14. Fluid flow and convective transport of solutes within the intervertebral disc.

    Science.gov (United States)

    Ferguson, Stephen J; Ito, Keita; Nolte, Lutz P

    2004-02-01

    Previous experimental and analytical studies of solute transport in the intervertebral disc have demonstrated that for small molecules diffusive transport alone fulfils the nutritional needs of disc cells. It has been often suggested that fluid flow into and within the disc may enhance the transport of larger molecules. The goal of the study was to predict the influence of load-induced interstitial fluid flow on mass transport in the intervertebral disc. An iterative procedure was used to predict the convective transport of physiologically relevant molecules within the disc. An axisymmetric, poroelastic finite-element structural model of the disc was developed. The diurnal loading was divided into discrete time steps. At each time step, the fluid flow within the disc due to compression or swelling was calculated. A sequentially coupled diffusion/convection model was then employed to calculate solute transport, with a constant concentration of solute being provided at the vascularised endplates and outer annulus. Loading was simulated for a complete diurnal cycle, and the relative convective and diffusive transport was compared for solutes with molecular weights ranging from 400 Da to 40 kDa. Consistent with previous studies, fluid flow did not enhance the transport of low-weight solutes. During swelling, interstitial fluid flow increased the unidirectional penetration of large solutes by approximately 100%. Due to the bi-directional temporal nature of disc loading, however, the net effect of convective transport over a full diurnal cycle was more limited (30% increase). Further study is required to determine the significance of large solutes and the timing of their delivery for disc physiology.

  15. Growth and evolution of satellites in a Jovian massive disc

    Science.gov (United States)

    Moraes, R. A.; Kley, W.; Vieira Neto, E.

    2018-03-01

    The formation of satellite systems in circum-planetary discs is considered to be similar to the formation of rocky planets in a proto-planetary disc, especially super-Earths. Thus, it is possible to use systems with large satellites to test formation theories that are also applicable to extrasolar planets. Furthermore, a better understanding of the origin of satellites might yield important information about the environment near the growing planet during the last stages of planet formation. In this work, we investigate the formation and migration of the Jovian satellites through N-body simulations. We simulated a massive, static, low-viscosity, circum-planetary disc in agreement with the minimum mass sub-nebula model prescriptions for its total mass. In hydrodynamic simulations, we found no signs of gaps, therefore type II migration is not expected. Hence, we used analytic prescriptions for type I migration, eccentricity and inclination damping, and performed N-body simulations with damping forces added. Detailed parameter studies showed that the number of final satellites is strong influenced by the initial distribution of embryos, the disc temperature, and the initial gas density profile. For steeper initial density profiles, it is possible to form systems with multiple satellites in resonance while a flatter profile favours the formation of satellites close to the region of the Galilean satellites. We show that the formation of massive satellites such as Ganymede and Callisto can be achieved for hotter discs with an aspect ratio of H/r ˜ 0.15 for which the ice line was located around 30RJ.

  16. Automated assembly of microfluidic "lab-on-a-disc"

    Science.gov (United States)

    Berger, M.; Müller, T.; Voebel, T.; Baum, C.; Glennon, T.; Mishra, R.; Kinahan, D.; King, D.; Ducrée, J.; Brecher, C.

    2018-02-01

    Point-of-care (POC) testing attracts more and more attention in the medical health sector because of their specific property to perform the diagnostic close to the patient. The fast diagnosis right at the hospital or the doctor's office improves the medical reaction time and the chances for a successful healing process. One of this POC test systems is a "Lab-on-a-Disc" (LoaD) which looks like a compact disc crisscrossed with microfluidic tubes and cavities. The fluid to be analysed is placed in the LoaD and an external device then rotates the LoaD. The cavities inside the LoaD and the centrifugal force ensure a clearly defined sequence of the analysis. Furthermore, we aim for an inexpensive manufacture of the medical product without neglecting its quality and functionality. Therefore, the Fraunhofer IPT works on an assembly cell to implement dissoluble films concisely into the disc. This dissoluble film demonstrates its successful usage as a gate for the fluid, which opens after a predefined moment in the cycle. Furthermore, we investigate to integrate a laser welding process into our gantry system and demonstrate its efficiency with the welding of polymer discs. This procedure is clinically safe because no further laser absorption material is needed in the sealing process, which might pollute the LoaD. Moreover, this process allows the alignment of several discs before the welding and therefore leads to precisely manufactured LoaDs in large quantities. All these methods together enable a fast, costefficient and reliable mass production to bring POC testing among the people.

  17. Intervertebral disc (IVD): Structure, degeneration, repair and regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Whatley, Benjamin R.; Wen Xuejun, E-mail: xjwen@clemson.edu

    2012-02-01

    Low back pain affects a large portion of the population, resulting in high care costs for therapy and treatment. One primary cause of low back pain is the degeneration of the intervertebral disc (IVD) resulting in the compression of the spinal nerves and adjacent vertebrae. Exact causes of degeneration are unknown, but it is thought that natural aging, and both biological and genetic factors may play a significant role in the degenerative process. Conventional methods to alleviate low back pain include spinal fusion and artificial disc replacement. Traditional treatments through spinal fusion may eliminate pain yet do not restore disc function and lead to further degeneration of adjacent levels by altering disc biomechanics and natural kinematics. Recently, artificial IVD replacements have started to gain interest, with two IVD implants currently approved in the United States. Although these implants facilitate the preservation of motions and disc space height, they are unable to sustain compressive forces due to their lack of elasticity. In addition, the implants may produce wear debris that can cause osteolysis and other deleterious effects. As an alternative to these conventional approaches, tissue engineered IVD constructs offer the advantage of biointegration while preserving the essential attributes of natural motion and disc space restoration. There is a great need for the development of tissue engineered scaffolds that simulate the natural 3D morphology and microenvironment of the targeted tissue. Scaffolds should facilitate biological transport to satisfy nutrition and waste removal requirements within the IVD. The discrete tissue architectures of the nucleus pulposus (NP) and annulus fibrosus (AF) have posed great challenges to IVD tissue engineering. Current attempts have not been able to satisfy the biological functions and/or mechanical properties of native tissue. Therefore, these current scaffolds are far from satisfactory. This review highlights the

  18. Intervertebral disc herniation: prevalence and association with ...

    African Journals Online (AJOL)

    Background: Low back pain is one of the common health problems encountered in life with intervertebral disc herniation being a common cause of its occurrence. Magnetic resonance imaging has emerged the gold standard for diagnosing a herniated disc. Aims and Objectives: To assess the frequency and pattern of ...

  19. The evolution of stellar exponential discs

    NARCIS (Netherlands)

    Ferguson, AMN; Clarke, CJ

    2001-01-01

    Models of disc galaxies which invoke viscosity-driven radial flows have long been known to provide a natural explanation for the origin of stellar exponential discs, under the assumption that the star formation and viscous time-scales are comparable. We present models which invoke simultaneous star

  20. Feature Based Control of Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh

    Two servo control loops are used to keep the Optical Pick-up Unit focused and radially on the information track of the Compact Disc. These control servos have problems handling surface faults on the Compact Disc. In this Ph.D thesis a method is proposed to improve the handling of these surface...

  1. Robust control of a compact disc mechanism

    NARCIS (Netherlands)

    Steinbuch, M.; Schootstra, G.; Bosgra, O.H.; Levine, W.S.

    1995-01-01

    A compact disc (CD) player is an optical decoding device that reproduces high-quality audio from a digitally coded signal recorded as a spiral-shaped track on a reflective disc. Apart from the audio application, other optical data systems (CD-ROM, optical data drive) and combined audio/video

  2. Computing Decoupled Residuals for Compact Disc Players

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Stoustrup, Jakob; Andersen, Palle

    2006-01-01

    a pair of residuals generated by Compact Disc Player. However, these residuals depend on the performance of position servos in the Compact Disc Player. In other publications of the same authors a pair of decoupled residuals is derived. However, the computation of these alternative residuals has been...

  3. Use NASA GES DISC Data in ArcGIS

    Science.gov (United States)

    Yang, Wenli; Pham, Long B.; Kempler, Steve

    2015-01-01

    This presentation describes GIS relevant data at NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), GES DISC Services and Support for GIS Users, and use cases of GES DISC data in ArcGIS.

  4. Characterization of the activity of β-galactosidase from Escherichia coli and Drosophila melanogaster in fixed and non-fixed Drosophila tissues

    Directory of Open Access Journals (Sweden)

    Mizuki Tomizawa

    2016-12-01

    Full Text Available β-Galactosidase encoded by the Escherichia coli lacZ gene, is widely used as a reporter molecule in molecular biology in a wide variety of animals. β-Galactosidase retains its enzymatic activity in cells or tissues even after fixation and can degrade X-Gal, a frequently used colormetric substrate, producing a blue color. Therefore, it can be used for the activity staining of fixed tissues. However, the enzymatic activity of the β-galactosidase that is ectopically expressed in the non-fixed tissues of animals has not been extensively studied. Here, we report the characterization of β-galactosidase activity in Drosophila tissues with and without fixation in various experimental conditions comparing the activity of two evolutionarily orthologous β-galactosidases derived from the E. coli lacZ and Drosophila melanogaster DmelGal genes. We performed quantitative analysis of the activity staining of larval imaginal discs and an in vitro assay using larval lysates. Our data showed that both E. coli and Drosophila β-galactosidase can be used for cell-type-specific activity staining, but they have their own preferences in regard to conditions. E. coli β-galactosidase showed a preference for neutral pH but not for acidic pH compared with Drosophila β-galactosidase. Our data suggested that both E. coli and Drosophila β-galactosidase show enzymatic activity in the physiological conditions of living animals when they are ectopically expressed in a desired specific spatial and temporal pattern. This may enable their future application to studies of chemical biology using model animals.

  5. Magnetic resonance imaging of intervertebral disc degeneration

    International Nuclear Information System (INIS)

    Maeda, Hiroshi; Noguchi, Masao; Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi.

    1993-01-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.)

  6. Magnetic resonance imaging of intervertebral disc degeneration

    Energy Technology Data Exchange (ETDEWEB)

    Maeda, Hiroshi; Noguchi, Masao (Kitakyushu City Yahata Hospital, Fukuoka (Japan)); Kira, Hideaki; Fujiki, Hiroshi; Shimokawa, Isao; Hinoue, Kaichi

    1993-02-01

    The aim of this study was to correlate the degree of lumbar intervertebral disc degeneration with findings of magnetic resonance imaging (MRI). Seventeen autopsied (from 7 patients) and 21 surgical (from 20 patients) intervertebral discs were used as specimens for histopathological examination. In addition, 21 intervertebral discs were examined on T2-weighted images. Histopathological findings from both autopsied and surgical specimens were well correlated with MRI findings. In particular, T2-weighted images reflected increased collagen fibers and rupture within the fibrous ring accurately. However, when severely degenerated intervertebral discs and hernia protruding the posterior longitudinal ligament existed, histological findings were not concordant well with T2-weighted images. Morphological appearances of autopsy specimens, divided into four on T2-weighted images, were well consistent with histological degeneration. This morphological classification, as shown on T2-weighted images, could also be used in the evaluation of intervertebral disc degeneration. (N.K.).

  7. The formation of planets by disc fragmentation

    Directory of Open Access Journals (Sweden)

    Stamatellos Dimitris

    2013-04-01

    Full Text Available I discuss the role that disc fragmentation plays in the formation of gas giant and terrestrial planets, and how this relates to the formation of brown dwarfs and low-mass stars, and ultimately to the process of star formation. Protostellar discs may fragment, if they are massive enough and can cool fast enough, but most of the objects that form by fragmentation are brown dwarfs. It may be possible that planets also form, if the mass growth of a proto-fragment is stopped (e.g. if this fragment is ejected from the disc, or suppressed and even reversed (e.g by tidal stripping. I will discuss if it is possible to distinguish whether a planet has formed by disc fragmentation or core accretion, and mention of a few examples of observed exoplanets that are suggestive of formation by disc fragmentation.

  8. T1 hyperintense disc in alkaptonuria.

    Science.gov (United States)

    Sag, Alan A; Silbergleit, Richard; Olson, Rick E; Wilson, Jon; Krishnan, Anant

    2012-10-01

    Case report. To report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation. A 46-year-old man without previous diagnosis of alkaptonuria underwent evaluation for progressive back pain revealing a T1-hyperintense disc herniation at the L3-L4 level. Discectomy recovered a blackened disc that was pathologically confirmed to be nucleus pulposus with alkaptonuric involvement. The differential diagnosis of a T1-hyperintense, T2-hypointense disc on magnetic resonance imaging is discussed, with emphasis on the pathophysiology of alkaptonuria. A single patient is reported. Pathologically proven patient presentation with radiological and pathological images. We report a rare case of alkaptonuria presenting as a T1-hyperintense disc herniation.

  9. Selector genes display tumor cooperation and inhibition in Drosophila epithelium in a developmental context-dependent manner

    Directory of Open Access Journals (Sweden)

    Ram Prakash Gupta

    2017-11-01

    Full Text Available During animal development, selector genes determine identities of body segments and those of individual organs. Selector genes are also misexpressed in cancers, although their contributions to tumor progression per se remain poorly understood. Using a model of cooperative tumorigenesis, we show that gain of selector genes results in tumor cooperation, but in only select developmental domains of the wing, haltere and eye-antennal imaginal discs of Drosophila larva. Thus, the field selector, Eyeless (Ey, and the segment selector, Ultrabithorax (Ubx, readily cooperate to bring about neoplastic transformation of cells displaying somatic loss of the tumor suppressor, Lgl, but in only those developmental domains that express the homeo-box protein, Homothorax (Hth, and/or the Zinc-finger protein, Teashirt (Tsh. In non-Hth/Tsh-expressing domains of these imaginal discs, however, gain of Ey in lgl− somatic clones induces neoplastic transformation in the distal wing disc and haltere, but not in the eye imaginal disc. Likewise, gain of Ubx in lgl− somatic clones induces transformation in the eye imaginal disc but not in its endogenous domain, namely, the haltere imaginal disc. Our results reveal that selector genes could behave as tumor drivers or inhibitors depending on the tissue contexts of their gains.

  10. Chasing discs around O-type (proto)stars: Evidence from ALMA observations

    Science.gov (United States)

    Cesaroni, R.; Sánchez-Monge, Á.; Beltrán, M. T.; Johnston, K. G.; Maud, L. T.; Moscadelli, L.; Mottram, J. C.; Ahmadi, A.; Allen, V.; Beuther, H.; Csengeri, T.; Etoka, S.; Fuller, G. A.; Galli, D.; Galván-Madrid, R.; Goddi, C.; Henning, T.; Hoare, M. G.; Klaassen, P. D.; Kuiper, R.; Kumar, M. S. N.; Lumsden, S.; Peters, T.; Rivilla, V. M.; Schilke, P.; Testi, L.; van der Tak, F.; Vig, S.; Walmsley, C. M.; Zinnecker, H.

    2017-06-01

    Context. Circumstellar discs around massive stars could mediate the accretion onto the star from the infalling envelope, and could minimize the effects of radiation pressure. Despite such a crucial role, only a few convincing candidates have been provided for discs around deeply embedded O-type (proto)stars. Aims: In order to establish whether disc-mediated accretion is the formation mechanism for the most massive stars, we have searched for circumstellar, rotating discs around a limited sample of six luminous (>105L⊙) young stellar objects. These objects were selected on the basis of their IR and radio properties in order to maximize the likelihood of association with disc+jet systems. Methods: We used ALMA with 0.̋2 resolution to observe a large number of molecular lines typical of hot molecular cores. In this paper we limit our analysis to two disc tracers (methyl cyanide, CH3CN, and its isotopologue, 13CH3CN), and an outflow tracer (silicon monoxide, SiO). Results: We reveal many cores, although their number depends dramatically on the target. We focus on the cores that present prominent molecular line emission. In six of these a velocity gradient is seen across the core,three of which show evidence of Keplerian-like rotation. The SiO data reveal clear but poorly collimated bipolar outflow signatures towards two objects only. This can be explained if real jets are rare (perhaps short-lived) in very massive objects and/or if stellar multiplicity significantly affects the outflow structure.For all cores with velocity gradients, the velocity field is analysed through position-velocity plots to establish whether the gas is undergoing rotation with νrot ∝ R- α, as expected for Keplerian-like discs. Conclusions: Our results suggest that in three objects we are observing rotation in circumstellar discs, with three more tentative cases, and one core where no evidence for rotation is found. In all cases but one, we find that the gas mass is less than the mass of

  11. A comparison of cup-to-disc ratio estimates by fundus biomicroscopy and stereoscopic optic disc photography in the Tema Eye Survey.

    Science.gov (United States)

    Mwanza, J C; Grover, D S; Budenz, D L; Herndon, L W; Nolan, W; Whiteside-de Vos, J; Hay-Smith, G; Bandi, J R; Bhansali, K A; Forbes, L A; Feuer, W J; Barton, K

    2017-08-01

    PurposeTo determine if there are systematic differences in cup-to-disc ratio (CDR) grading using fundus biomicroscopy compared to stereoscopic disc photograph reading.MethodsThe vertical cup-to-disc ratio (VCDR) and horizontal cup-to-disc ratio (HCDR) of 2200 eyes (testing set) were graded by glaucoma subspecialists through fundus biomicroscopy and by a reading center using stereoscopic disc photos. For validation, the glaucoma experts also estimated VCDR and HCDR using stereoscopic disc photos in a subset of 505 eyes that they had assessed biomicroscopically. Agreement between grading methods was assessed with Bland-Altman plots.ResultsIn both sets, photo reading tended to yield small CDRs marginally larger, but read large CDRs marginally smaller than fundus biomicroscopy. The mean differences in VCDR and HCDR were 0.006±0.18 and 0.05±0.18 (testing set), and -0.053±0.23 and -0.028±0.21 (validation set), respectively. The limits of agreement were ~0.4, which is twice as large as the cutoff of clinically significant CDR difference between methods. CDR estimates differed by 0.2 or more in 33.8-48.7% between methods.ConclusionsThe differences in CDR estimates between fundus biomicroscopy and stereoscopic optic disc photo reading showed a wide variation, and reached clinically significance threshold in a large proportion of patients, suggesting a poor agreement. Thus, glaucoma should be monitored by comparing baseline and subsequent CDR estimates using the same method rather than comparing photographs to fundus biomicroscopy.

  12. The Gaia-ESO Survey: the Galactic thick to thin disc transition

    Science.gov (United States)

    Recio-Blanco, A.; de Laverny, P.; Kordopatis, G.; Helmi, A.; Hill, V.; Gilmore, G.; Wyse, R.; Adibekyan, V.; Randich, S.; Asplund, M.; Feltzing, S.; Jeffries, R.; Micela, G.; Vallenari, A.; Alfaro, E.; Allende Prieto, C.; Bensby, T.; Bragaglia, A.; Flaccomio, E.; Koposov, S. E.; Korn, A.; Lanzafame, A.; Pancino, E.; Smiljanic, R.; Jackson, R.; Lewis, J.; Magrini, L.; Morbidelli, L.; Prisinzano, L.; Sacco, G.; Worley, C. C.; Hourihane, A.; Bergemann, M.; Costado, M. T.; Heiter, U.; Joffre, P.; Lardo, C.; Lind, K.; Maiorca, E.

    2014-07-01

    Aims: The nature of the thick disc and its relation to the thin disc is presently an important subject of debate. In fact, the structural and chemo-dynamical transition between disc populations can be used as a test of the proposed models of Galactic disc formation and evolution. Methods: We used the atmospheric parameters, [α/Fe] abundances, and radial velocities, which were determined from the Gaia-ESO Survey GIRAFFE spectra of FGK-type stars (first nine months of observations) to provide a chemo-kinematical characterisation of the disc stellar populations. We focussed on a subsample of 1016 stars with high-quality parameters, covering the volume | Z | contamination by thin disc stars suggests a gradient up to 64 ± 9 km s-1 dex-1. The distributions of azimuthal velocity, vertical velocity, and orbital parameters are also analysed for the chemically separated samples. Concerning the gradients with galactocentric radius, we find, for the thin disc, a flat behaviour of the azimuthal velocity, a metallicity gradient equal to -0.058 ± 0.008 dex kpc-1 and a very small positive [α/Fe] gradient. For the thick disc, flat gradients in [M/H] and [α/Fe] are derived. Conclusions: Our chemo-kinematical analysis suggests a picture where the thick disc seems to have experienced a settling process, during which its rotation increased progressively and, possibly, the azimuthal velocity dispersion decreased. At [M/H] ≈ -0.25 dex and [α/Fe]≈ 0.1 dex, the mean characteristics of the thick disc in vertical distance to the Galactic plane, rotation, rotational dispersion, and stellar orbits' eccentricity agree with that of the thin disc stars of the same metallicity, suggesting a possible connection between these two populations at a certain epoch of the disc evolution. Finally, the results presented here, based only on the first months of the Gaia ESO Survey observations, confirm how crucial large high-resolution spectroscopic surveys outside the solar neighbourhood are today

  13. Biases in Drosophila melanogaster protein trap screens

    Directory of Open Access Journals (Sweden)

    Müller Ilka

    2009-05-01

    utility of P-element vectors for protein trap screens has largely been exhausted, and that approximately 2,800 genes may still be amenable using piggyBac vectors. Thus protein trap strategies based on current approaches are unlikely to offer true genome-wide coverage. We suggest that either transposons with reduced insertion bias or recombineering-based targeting techniques will be required for comprehensive genome coverage in Drosophila.

  14. Phylogeny of the Genus Drosophila

    Science.gov (United States)

    O’Grady, Patrick M.; DeSalle, Rob

    2018-01-01

    Understanding phylogenetic relationships among taxa is key to designing and implementing comparative analyses. The genus Drosophila, which contains over 1600 species, is one of the most important model systems in the biological sciences. For over a century, one species in this group, Drosophila melanogaster, has been key to studies of animal development and genetics, genome organization and evolution, and human disease. As whole-genome sequencing becomes more cost-effective, there is increasing interest in other members of this morphologically, ecologically, and behaviorally diverse genus. Phylogenetic relationships within Drosophila are complicated, and the goal of this paper is to provide a review of the recent taxonomic changes and phylogenetic relationships in this genus to aid in further comparative studies. PMID:29716983

  15. Observability of planet-disc interactions in CO kinematics

    Science.gov (United States)

    Pérez, Sebastián; Casassus, S.; Benítez-Llambay, P.

    2018-06-01

    Empirical evidence of planets in gas-rich circumstellar discs is required to constrain giant planet formation theories. Here we study the kinematic patterns which arise from planet-disc interactions and their observability in CO rotational emission lines. We perform three-dimensional hydrodynamical simulations of single giant planets, and predict the emergent intensity field with radiative transfer. Pressure gradients at planet-carved gaps, spiral wakes and vortices bear strong kinematic counterparts. The iso-velocity contours in the CO(2-1) line centroids vo reveal large-scale perturbations, corresponding to abrupt transitions from below sub-Keplerian to super-Keplerian rotation along with radial and vertical flows. The increase in line optical depth at the edge of the gap also modulates vo, but this is a mild effect compared to the dynamical imprint of the planet-disc interaction. The large-scale deviations from the Keplerian rotation thus allow the planets to be indirectly detected via the first moment maps of molecular gas tracers, at ALMA angular resolutions. The strength of these deviations depends on the mass of the perturber. This initial study paves the way to eventually determine the mass of the planet by comparison with more detailed models.

  16. Notch-dependent epithelial fold determines boundary formation between developmental fields in the Drosophila antenna.

    Science.gov (United States)

    Ku, Hui-Yu; Sun, Y Henry

    2017-07-01

    Compartment boundary formation plays an important role in development by separating adjacent developmental fields. Drosophila imaginal discs have proven valuable for studying the mechanisms of boundary formation. We studied the boundary separating the proximal A1 segment and the distal segments, defined respectively by Lim1 and Dll expression in the eye-antenna disc. Sharp segregation of the Lim1 and Dll expression domains precedes activation of Notch at the Dll/Lim1 interface. By repressing bantam miRNA and elevating the actin regulator Enable, Notch signaling then induces actomyosin-dependent apical constriction and epithelial fold. Disruption of Notch signaling or the actomyosin network reduces apical constriction and epithelial fold, so that Dll and Lim1 cells become intermingled. Our results demonstrate a new mechanism of boundary formation by actomyosin-dependent tissue folding, which provides a physical barrier to prevent mixing of cells from adjacent developmental fields.

  17. Intervertebral Disc Characteristic on Progressive Neurological Deficit

    Directory of Open Access Journals (Sweden)

    Farid Yudoyono

    2017-09-01

    Full Text Available Objective: To examine the intervertebral disc characteristic on magnetic resonance imaging (MRI in lumbar herniated disc (LHD patients with progressive neurological deficit. Methods: Patients were collected retrospectively from Dr. Hasan Sadikin General Hospital Database from 2011–2013 with LHD, had neurological deficit such as radiculopathy and cauda equine syndrome for less than four weeks with a positive sign confirmed by neurological examination and confirmatory with MRI examination. Results: A total of 14 patients with lumbar herniated disc disease (10 males, 4 females suffered from progressive neurological deficit with an average age of (52.07±10.9 years old. Early disc height was 9.38±0.5 mm and progressive neurological deficit state disc height was 4.03±0.53 mm, which were significantly different statisticaly (p<0.01. Symptoms of radiculopathy were seen in 11 patients and cauda equine syndrome in three patients. Modic changes grade 1 was found in five patients, grade 2 in eight patients,grade 3 in one patient, Pfirmman grade 2 in eleven patients and grade 3 in three patients. Thecal sac compression 1/3 compression was seen in four patients and 2/3 compression in ten patients. Conclusions: Neurosurgeon should raise concerns on the characteristic changes of intervertebral disc in magnetic resonance imaging examination to avoid further neural injury in lumbar herniated disc patients.

  18. Deep-down ionization of protoplanetary discs

    Science.gov (United States)

    Glassgold, A. E.; Lizano, S.; Galli, D.

    2017-12-01

    The possible occurrence of dead zones in protoplanetary discs subject to the magneto-rotational instability highlights the importance of disc ionization. We present a closed-form theory for the deep-down ionization by X-rays at depths below the disc surface dominated by far-ultraviolet radiation. Simple analytic solutions are given for the major ion classes, electrons, atomic ions, molecular ions and negatively charged grains. In addition to the formation of molecular ions by X-ray ionization of H2 and their destruction by dissociative recombination, several key processes that operate in this region are included, e.g. charge exchange of molecular ions and neutral atoms and destruction of ions by grains. Over much of the inner disc, the vertical decrease in ionization with depth into the disc is described by simple power laws, which can easily be included in more detailed modelling of magnetized discs. The new ionization theory is used to illustrate the non-ideal magnetohydrodynamic effects of Ohmic, Hall and Ambipolar diffusion for a magnetic model of a T Tauri star disc using the appropriate Elsasser numbers.

  19. Fluctuation-Driven Neural Dynamics Reproduce Drosophila Locomotor Patterns.

    Directory of Open Access Journals (Sweden)

    Andrea Maesani

    2015-11-01

    Full Text Available The neural mechanisms determining the timing of even simple actions, such as when to walk or rest, are largely mysterious. One intriguing, but untested, hypothesis posits a role for ongoing activity fluctuations in neurons of central action selection circuits that drive animal behavior from moment to moment. To examine how fluctuating activity can contribute to action timing, we paired high-resolution measurements of freely walking Drosophila melanogaster with data-driven neural network modeling and dynamical systems analysis. We generated fluctuation-driven network models whose outputs-locomotor bouts-matched those measured from sensory-deprived Drosophila. From these models, we identified those that could also reproduce a second, unrelated dataset: the complex time-course of odor-evoked walking for genetically diverse Drosophila strains. Dynamical models that best reproduced both Drosophila basal and odor-evoked locomotor patterns exhibited specific characteristics. First, ongoing fluctuations were required. In a stochastic resonance-like manner, these fluctuations allowed neural activity to escape stable equilibria and to exceed a threshold for locomotion. Second, odor-induced shifts of equilibria in these models caused a depression in locomotor frequency following olfactory stimulation. Our models predict that activity fluctuations in action selection circuits cause behavioral output to more closely match sensory drive and may therefore enhance navigation in complex sensory environments. Together these data reveal how simple neural dynamics, when coupled with activity fluctuations, can give rise to complex patterns of animal behavior.

  20. Late replication domains are evolutionary conserved in the Drosophila genome.

    Science.gov (United States)

    Andreyenkova, Natalya G; Kolesnikova, Tatyana D; Makunin, Igor V; Pokholkova, Galina V; Boldyreva, Lidiya V; Zykova, Tatyana Yu; Zhimulev, Igor F; Belyaeva, Elena S

    2013-01-01

    Drosophila chromosomes are organized into distinct domains differing in their predominant chromatin composition, replication timing and evolutionary conservation. We show on a genome-wide level that genes whose order has remained unaltered across 9 Drosophila species display late replication timing and frequently map to the regions of repressive chromatin. This observation is consistent with the existence of extensive domains of repressive chromatin that replicate extremely late and have conserved gene order in the Drosophila genome. We suggest that such repressive chromatin domains correspond to a handful of regions that complete replication at the very end of S phase. We further demonstrate that the order of genes in these regions is rarely altered in evolution. Substantial proportion of such regions significantly coincide with large synteny blocks. This indicates that there are evolutionary mechanisms maintaining the integrity of these late-replicating chromatin domains. The synteny blocks corresponding to the extremely late-replicating regions in the D. melanogaster genome consistently display two-fold lower gene density across different Drosophila species.

  1. Modelling Cooperative Tumorigenesis in Drosophila

    Science.gov (United States)

    2018-01-01

    The development of human metastatic cancer is a multistep process, involving the acquisition of several genetic mutations, tumour heterogeneity, and interactions with the surrounding microenvironment. Due to the complexity of cancer development in mammals, simpler model organisms, such as the vinegar fly, Drosophila melanogaster, are being utilized to provide novel insights into the molecular mechanisms involved. In this review, we highlight recent advances in modelling tumorigenesis using the Drosophila model, focusing on the cooperation of oncogenes or tumour suppressors, and the interaction of mutant cells with the surrounding tissue in epithelial tumour initiation and progression. PMID:29693007

  2. Modelling Cooperative Tumorigenesis in Drosophila

    Directory of Open Access Journals (Sweden)

    Helena E. Richardson

    2018-01-01

    Full Text Available The development of human metastatic cancer is a multistep process, involving the acquisition of several genetic mutations, tumour heterogeneity, and interactions with the surrounding microenvironment. Due to the complexity of cancer development in mammals, simpler model organisms, such as the vinegar fly, Drosophila melanogaster, are being utilized to provide novel insights into the molecular mechanisms involved. In this review, we highlight recent advances in modelling tumorigenesis using the Drosophila model, focusing on the cooperation of oncogenes or tumour suppressors, and the interaction of mutant cells with the surrounding tissue in epithelial tumour initiation and progression.

  3. Adaptive Evolution of Gene Expression in Drosophila.

    Science.gov (United States)

    Nourmohammad, Armita; Rambeau, Joachim; Held, Torsten; Kovacova, Viera; Berg, Johannes; Lässig, Michael

    2017-08-08

    Gene expression levels are important quantitative traits that link genotypes to molecular functions and fitness. In Drosophila, population-genetic studies have revealed substantial adaptive evolution at the genomic level, but the evolutionary modes of gene expression remain controversial. Here, we present evidence that adaptation dominates the evolution of gene expression levels in flies. We show that 64% of the observed expression divergence across seven Drosophila species are adaptive changes driven by directional selection. Our results are derived from time-resolved data of gene expression divergence across a family of related species, using a probabilistic inference method for gene-specific selection. Adaptive gene expression is stronger in specific functional classes, including regulation, sensory perception, sexual behavior, and morphology. Moreover, we identify a large group of genes with sex-specific adaptation of expression, which predominantly occurs in males. Our analysis opens an avenue to map system-wide selection on molecular quantitative traits independently of their genetic basis. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  4. Giant planet migration during FU Orionis outbursts: 1D disc models

    Science.gov (United States)

    Dunhill, A. C.

    2018-05-01

    I present the results of semi-analytic calculations of migrating planets in young, outbursting circumstellar discs. Formed far out in the disc via gravitational fragmentation early on in its lifetime, these planets typically migrate at very slow rates and are therefore mostly expected to remain at large radii (such as is the case in HR 8799). I show that changes in the disc structure during FUor outbursts affect the planet's ability to maintain a gap and can allow a massive giant planet's semimajor axis to reduce by almost 5 per cent in a single outburst under the most optimistic conditions. Given that a single disc will likely undergo ˜10 such outbursts this process can significantly alter the expected radial distribution for GI-formed planets.

  5. Likelihood inference for unions of interacting discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, K.

    2010-01-01

    This is probably the first paper which discusses likelihood inference for a random set using a germ-grain model, where the individual grains are unobservable, edge effects occur and other complications appear. We consider the case where the grains form a disc process modelled by a marked point...... process, where the germs are the centres and the marks are the associated radii of the discs. We propose to use a recent parametric class of interacting disc process models, where the minimal sufficient statistic depends on various geometric properties of the random set, and the density is specified......-based maximum likelihood inference and the effect of specifying different reference Poisson models....

  6. Spectroscopic Parameters of Lumbar Intervertebral Disc Material

    Science.gov (United States)

    Terbetas, G.; Kozlovskaja, A.; Varanius, D.; Graziene, V.; Vaitkus, J.; Vaitkuviene, A.

    2009-06-01

    There are numerous methods of investigating intervertebral disc. Visualization methods are widely used in clinical practice. Histological, imunohistochemical and biochemical methods are more used in scientific research. We propose that a new spectroscopic investigation would be useful in determining intervertebral disc material, especially when no histological specimens are available. Purpose: to determine spectroscopic parameters of intervertebral disc material; to determine emission spectra common for all intervertebral discs; to create a background for further spectroscopic investigation where no histological specimen will be available. Material and Methods: 20 patients, 68 frozen sections of 20 μm thickness from operatively removed intervertebral disc hernia were excited by Nd:YAG microlaser STA-01-TH third harmonic 355 nm light throw 0, 1 mm fiber. Spectrophotometer OceanOptics USB2000 was used for spectra collection. Mathematical analysis of spectra was performed by ORIGIN multiple Gaussian peaks analysis. Results: In each specimen of disc hernia were found distinct maximal spectral peaks of 4 types supporting the histological evaluation of mixture content of the hernia. Fluorescence in the spectral regions 370-700 nm was detected in the disc hernias. The main spectral component was at 494 nm and the contribution of the components with the peak wavelength values at 388 nm, 412 nm and 435±5 nm were varying in the different groups of samples. In comparison to average spectrum of all cases, there are 4 groups of different spectral signatures in the region 400-500 nm in the patient groups, supporting a clinical data on different clinical features of the patients. Discussion and Conclusion: besides the classical open discectomy, new minimally invasive techniques of treating intervertebral disc emerge (PLDD). Intervertebral disc in these techniques is assessed by needle, no histological specimen is taken. Spectroscopic investigation via fiber optics through the

  7. High-energy radiation from collisions of high-velocity clouds and the Galactic disc

    Science.gov (United States)

    del Valle, Maria V.; Müller, A. L.; Romero, G. E.

    2018-04-01

    High-velocity clouds (HVCs) are interstellar clouds of atomic hydrogen that do not follow normal Galactic rotation and have velocities of a several hundred kilometres per second. A considerable number of these clouds are falling down towards the Galactic disc. HVCs form large and massive complexes, so if they collide with the disc a great amount of energy would be released into the interstellar medium. The cloud-disc interaction produces two shocks: one propagates through the cloud and the other through the disc. The properties of these shocks depend mainly on the cloud velocity and the disc-cloud density ratio. In this work, we study the conditions necessary for these shocks to accelerate particles by diffusive shock acceleration and we study the non-thermal radiation that is produced. We analyse particle acceleration in both the cloud and disc shocks. Solving a time-dependent two-dimensional transport equation for both relativistic electrons and protons, we obtain particle distributions and non-thermal spectral energy distributions. In a shocked cloud, significant synchrotron radio emission is produced along with soft gamma rays. In the case of acceleration in the shocked disc, the non-thermal radiation is stronger; the gamma rays, of leptonic origin, might be detectable with current instruments. A large number of protons are injected into the Galactic interstellar medium, and locally exceed the cosmic ray background. We conclude that under adequate conditions the contribution from HVC-disc collisions to the galactic population of relativistic particles and the associated extended non-thermal radiation might be important.

  8. Generation of New Hairless Alleles by Genomic Engineering at the Hairless Locus in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Heiko Praxenthaler

    Full Text Available Hairless (H is the major antagonist within the Notch signalling pathway of Drosophila melanogaster. By binding to Suppressor of Hairless [Su(H] and two co-repressors, H induces silencing of Notch target genes in the absence of Notch signals. We have applied genomic engineering to create several new H alleles. To this end the endogenous H locus was replaced with an attP site by homologous recombination, serving as a landing platform for subsequent site directed integration of different H constructs. This way we generated a complete H knock out allele HattP, reintroduced a wild type H genomic and a cDNA-construct (Hgwt, Hcwt as well as two constructs encoding H proteins defective of Su(H binding (HLD, HiD. Phenotypes regarding viability, bristle and wing development were recorded, and the expression of Notch target genes wingless and cut was analysed in mutant wing discs or in mutant cell clones. Moreover, genetic interactions with Notch (N5419 and Delta (DlB2 mutants were addressed. Overall, phenotypes were largely as expected: both HLD and HiD were similar to the HattP null allele, indicating that most of H activity requires the binding of Su(H. Both rescue constructs Hgwt and Hcwt were homozygous viable without phenotype. Unexpectedly, the hemizygous condition uncovered that they were not identical to the wild type allele: notably Hcwt showed a markedly reduced activity, suggesting the presence of as yet unidentified regulatory or stabilizing elements in untranslated regions of the H gene. Interestingly, Hgwt homozygous cells expressed higher levels of H protein, perhaps unravelling gene-by-environment interactions.

  9. Temporal and spatial expression of Drosophila DLGS97 during neural development.

    Science.gov (United States)

    Albornoz, Valeria; Mendoza-Topaz, Carolina; Oliva, Carlos; Tello, Judith; Olguín, Patricio; Sierralta, Jimena

    2008-07-01

    The products of the Drosophila discs-large (dlg) gene are members of the MAGUK family of proteins, a group of proteins involved in localization, transport and recycling of receptors and channels in cell junctions, including the synapse. In vertebrates, four genes with multiple splice variants homologous to dlg are described. dlg originates two main proteins, DLGA, similar to the vertebrate neuronal protein PSD95, and DLGS97, similar to the vertebrate neuronal and epithelial protein SAP97. DLGA is expressed in epithelia, neural tissue and muscle. DLGS97 is expressed in neural tissue and muscle but not in epithelia. The distinctive difference between them is the presence in DLGS97 of an L27 domain. The differential expression between these variants makes the study of DLGS97 of key relevance to understand the in vivo role of synaptic MAGUKs in neurons. Here we present the temporal and spatial expression pattern of DLGS97 during embryonic and larval nervous system development, during eye development and in adult brain. Our results show that DLGS97 is expressed zygotically, in neurons in the embryo, larvae and adult, and is absent at all stages in glial cells. During eye development DLGS97 starts to be expressed in photoreceptor cells at early stages of differentiation and localizes basal to the basolateral junctions. In the brain, DLGS97 is expressed in the mushroom bodies and optic lobes at larval and adult stages; and in the antennal lobe in the adult stage. In addition we show that both, dlgS97 and dlgA transcripts, express during development multiple splice variants with differences in the use of exons in two sites.

  10. Thermal analysis on motorcycle disc brake geometry

    Science.gov (United States)

    W. M. Zurin W., S.; Talib, R. J.; Ismail, N. I.

    2017-08-01

    Braking is a phase of slowing and stop the movement of motorcycle. During braking, the frictional heat was generated and the energy was ideally should be faster dissipated to surrounding to prevent the built up of the excessive temperature which may lead to brake fluid vaporization, thermoelastic deformation at the contact surface, material degradation and failure. In this paper, solid and ventilated type of motorcycle disc brake are being analyse using Computational Fluid Dynamic (CFD) software. The main focus of the analysis is the thermal behaviour during braking for solid and ventilated disc brake. A comparison between both geometries is being discussed to determine the better braking performance in term of temperature distribution. It is found that ventilated disc brake is having better braking performance in terms of heat transfer compare to solid disc.

  11. Hydrodynamic forces on two moving discs

    Directory of Open Access Journals (Sweden)

    Burton D.A.

    2004-01-01

    Full Text Available We give a detailed presentation of a flexible method for constructing explicit expressions of irrotational and incompressible fluid flows around two rigid circular moving discs. We also discuss how such expressions can be used to compute the fluid-induced forces and torques on the discs in terms of Killing drives. Conformal mapping techniques are used to identify a meromorphic function on an annular region in C with a flow around two circular discs by a Mobius transformation. First order poles in the annular region correspond to vortices outside of the two discs. Inflows are incorporated by putting a second order pole at the point in the annulus that corresponds to infinity.

  12. Locally prepared antibiotic sensitivity discs: a substitute for imported ...

    African Journals Online (AJOL)

    Zones of inhibition were compared with those obtained from commercial antibiotic discs. Results obtained showed that discs prepared locally from antibiotic tablets, performed comparably with commercially obtained discs. There was no significant statistical difference between the two tested discs. We therefore recommend ...

  13. Optic Disc Pit with Sectorial Retinitis Pigmentosa

    OpenAIRE

    Balikoglu-Yilmaz, Melike; Taskapili, Muhittin; Yilmaz, Tolga; Teke, Mehmet Yasin

    2013-01-01

    Sectorial retinitis pigmentosa (RP) and optic disc pit (ODP) are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, ...

  14. The lowest surface brightness disc galaxy known

    International Nuclear Information System (INIS)

    Davies, J.I.; Phillipps, S.; Disney, M.J.

    1988-01-01

    The discovery of a galaxy with a prominent bulge and a dominant extremely low surface brightness disc component is reported. The profile of this galaxy is very similar to the recently discovered giant low surface brightness galaxy Malin 1. The disc central surface brightness is found to be ∼ 26.4 Rμ, some 1.5 mag fainter than Malin 1 and thus by far the lowest yet observed. (author)

  15. Spontaneous Resolution of Optic Disc Pit Maculopathy

    OpenAIRE

    Tripathy, Koushik

    2017-01-01

    I read with interest the article reporting spontaneous resolution of optic disc pit maculopathy in a boy.1 Though the presence of an optic disc pit and associated macular involvement is undoubted in the presented case, the provided optical coherence tomography (OCT) does not clearly show typical intraretinal schisis (Figure 1B)1 at multiple retinal levels which may communicate with the pit. Instead, it shows a sub-internal limiting membrane (sub-ILM) cavity. Such cavities are known to occur f...

  16. Loss of notochordal cell phenotype in 3D-cell cultures: implications for disc physiology and disc repair.

    Science.gov (United States)

    Omlor, G W; Nerlich, A G; Tirlapur, U K; Urban, J P; Guehring, T

    2014-12-01

    Embryonic notochordal disc nucleus cells (NC) have been identified to protect disc tissue against disc degeneration but in human beings NC phenotype gets lost with aging and the pathophysiological mechanisms are poorly understood. NC may stimulate other cells via soluble factors, and NC-conditioned medium can be used to stimulate matrix production of other disc cells and mesenchymal stem cells and thus may be of special interest for biological disc repair. As this stimulatory effect is associated with the NC phenotype, we investigated how cell morphology and gene-expression of the NC phenotype changes with time in 3D-cell culture. NC and inner annulus chondrocyte-like cells (CLC) from immature pigtails (freshly isolated cells/tissue, 3D-alginate beads, 3D-clusters) were cultured for up to 16 days under normoxia and hypoxia. Protein-expression was analysed by immunohistology and gene-expression analysis was carried out on freshly isolated cells and cultured cells. Cell morphology and proliferation were analysed by two-photon-laser-microscopy. Two-photon-laser-microscopy showed a homogenous and small CLC population in the inner annulus, which differed from the large vacuole-containing NC in the nucleus. Immunohistology found 93 % KRT8 positive cells in the nucleus and intracellular and pericellular Col2, IL6, and IL12 staining while CLC were KRT8 negative. Freshly isolated NC showed significantly higher KRT8 and CAIII but lower Col2 gene-expression than CLC. NC in 3D-cultures demonstrated significant size reduction and loss of vacuoles with culture time, all indicating a loss of the characteristic NC morphology. Hypoxia reduced the rate of decrease in NC size and vacuoles. Gene-expression of KRT8 and CAIII in NC fell significantly early in culture while Col2 did not decrease significantly within the culture period. In CLC, KRT8 and CAIII gene-expression was low and did not change noticeably in culture, whereas Col2 expression fell with time in culture. 3D

  17. Protoplanetary disc response to distant tidal encounters in stellar clusters

    Science.gov (United States)

    Winter, A. J.; Clarke, C. J.; Rosotti, G.; Booth, R. A.

    2018-04-01

    The majority of stars form in a clustered environment. This has an impact on the evolution of surrounding protoplanetary discs (PPDs) due to either photoevaporation or tidal truncation. Consequently, the development of planets depends on formation environment. Here, we present the first thorough investigation of tidally induced angular momentum loss in PPDs in the distant regime, partly motivated by claims in the literature for the importance of distant encounters in disc evolution. We employ both theoretical predictions and dynamical/hydrodynamical simulations in 2D and 3D. Our theoretical analysis is based on that of Ostriker (1994) and leads us to conclude that in the limit that the closest approach distance xmin ≫ r, the radius of a particle ring, the fractional change in angular momentum scales as (xmin/r)-5. This asymptotic limit ensures that the cumulative effect of distant encounters is minor in terms of its influence on disc evolution. The angular momentum transfer is dominated by the m = 2 Lindblad resonance for closer encounters and by the m = 1, ω = 0 Lindblad resonance at large xmin/r. We contextualize these results by comparing expected angular momentum loss for the outer edge of a PPD due to distant and close encounters. Contrary to the suggestions of previous works, we do not find that distant encounters contribute significantly to angular momentum loss in PPDs. We define an upper limit for closest approach distance where interactions are significant as a function of arbitrary host to perturber mass ratio M2/M1.

  18. Tidal Dwarf Galaxies: Disc Formation at \\(z\\simeq0\\

    Directory of Open Access Journals (Sweden)

    Federico Lelli

    2015-11-01

    Full Text Available Collisional debris around interacting and post-interacting galaxies often display condensations of gas and young stars that can potentially form gravitationally bound objects: Tidal Dwarf Galaxies (TDGs. We summarise recent results on TDGs, which are originally published in Lelli et al. (2015, A&A.We study a sample of six TDGs around three different interacting systems, using high-resolution HI observations from the Very Large Array. We find that the HI emission associated to TDGs can be described by rotating disc models. These discs, however, would have undergone less than one orbit since the time of the TDG formation, raising the question of whether they are in dynamical equilibrium. Assuming that TDGs are in dynamical equilibrium, we find that the ratio of dynamical mass to baryonic mass is consistent with one, implying that TDGs are devoid of dark matter. This is in line with the results of numerical simulations where tidal forces effectively segregate dark matter in the halo from baryonic matter in the disc, which ends up forming tidal tails and TDGs.

  19. Disc type thermal actuator with straight beams for angular motion

    International Nuclear Information System (INIS)

    Anwar, M. Arefin; Packirisamy, Muthukumaran; Ahmed, A.K. Waiz

    2013-01-01

    Motion of a micro thermal actuator largely depends on its structural topology. This paper presents designs for a novel rotary type micro thermal actuator. This actuator has unique arrangement of hot segments around the cold segment. Upon application of potential difference, hot segments expand against the cold segment of disc and make the cold disc rotate about its center. This rotary motion can be used for various optical applications like, switching, attenuation and diffraction. The actuator has been fabricated using poly MUMPS process technology. An analytical model was used for predicting steady state temperature profile along the actuator length and rotational behavior of the cold disc under different applied voltages. A finite element analysis (FEA) was carried out to predict the behavior of the actuator by defining an air volume around the structure and also between structure and substrate. Finally testing was done for predicting feasibility of the actuator. Comparison of the rotational behavior obtained from both analytical model and FEA with that of obtained from testing shows close agreement. -- Highlights: ► Electro-thermo-mechanical modeling and verification of rotary micro thermal actuator. ► Modeling with conduction, convection and radiation modes for the air gap below 3 micron. ► In micro level, shape factor and material resistivity were estimated and verified through I–V characteristics. ► Two different designs of different shape factors were designed, fabricated and tested. ► The devices were fabricated using surface micromachining technology and tested for verification

  20. Drosophila learn efficient paths to a food source

    OpenAIRE

    Stewart, James; Lim, Terrence; Claridge-Chang, Adam; Wang, Zhiping; Toh, Alicia; Rahman, Mashiur; Navawongse, Rapeechai; Raczkowska, Marlena; Choudhury, Deepak

    2016-01-01

    Elucidating the genetic, and neuronal bases for learned behavior is a central problem in neuroscience. A leading system for neurogenetic discovery is the vinegar fly Drosophila melanogaster; fly memory research has identified genes and circuits that mediate aversive and appetitive learning. However, methods to study adaptive food-seeking behavior in this animal have lagged decades behind rodent feeding analysis, largely due to the challenges presented by their small scale. There is currently ...

  1. The vortex structure and flux creep within superconducting permanent-magnet high aspect-ratio discs

    International Nuclear Information System (INIS)

    Watson, J.H.P.; Younas, I.

    1997-01-01

    Inhomogeneous type II superconducting discs magnetized by an applied field will retain some magnetization when field is switched off so the superconducting disc will behave as a permanent magnet after flux creep has reduced to a low value.This paper examines the superconducting vortex structure within superconducting permanent-magnet high aspect-ratio discs which is consistent with the calculated magnetic field distribution.The discs, with radius R, have the axis along the z-direction and the mid-plane of the disc corresponds to z = 0. These discs with large aspect ratios in the remnant state have a region between radius r l and R where the magnetic field is reversed. Surrounding the line r = r l and z = 0 there is a region where H cl which is in the Meissner state. Near r l the vortex lines are strongly curved. For radii r l vortex lines creep to larger values of r. For radii r > r l vortex lines creep to smaller values of r, meet at r l with vortex lines of opposite sign and form a continuous loop which decreases in size and is finally annihilated in the Meissner region. Flux creep induces lossless currents in the Meissner region. (author)

  2. Harvesting the decay energy of 26Al to drive lightning discharge in protoplanetary discs

    Science.gov (United States)

    Johansen, Anders; Okuzumi, Satoshi

    2018-01-01

    Chondrules in primitive meteorites likely formed by recrystallisation of dust aggregates that were flash-heated to nearly complete melting. Chondrules may represent the building blocks of rocky planetesimals and protoplanets in the inner regions of protoplanetary discs, but the source of ubiquitous thermal processing of their dust aggregate precursors remains elusive. Here we demonstrate that escape of positrons released in the decay of the short-lived radionuclide 26Al leads to a large-scale charging of dense pebble structures, resulting in neutralisation by lightning discharge and flash-heating of dust and pebbles. This charging mechanism is similar to a nuclear battery where a radioactive source charges a capacitor. We show that the nuclear battery effect operates in circumplanetesimal pebble discs. The extremely high pebble densities in such discs are consistent with conditions during chondrule heating inferred from the high abundance of sodium within chondrules. The sedimented mid-plane layer of the protoplanetary disc may also be prone to charging by the emission of positrons, if the mass density of small dust there is at least an order of magnitude above the gas density. Our results imply that the decay energy of 26Al can be harvested to drive intense lightning activity in protoplanetary discs. The total energy stored in positron emission is comparable to the energy needed to melt all solids in the protoplanetary disc. The efficiency of transferring the positron energy to the electric field nevertheless depends on the relatively unknown distribution and scale-dependence of pebble density gradients in circumplanetesimal pebble discs and in the protoplanetary disc mid-plane layer.

  3. Drosophila Vps13 Is Required for Protein Homeostasis in the Brain.

    Directory of Open Access Journals (Sweden)

    Jan J Vonk

    Full Text Available Chorea-Acanthocytosis is a rare, neurodegenerative disorder characterized by progressive loss of locomotor and cognitive function. It is caused by loss of function mutations in the Vacuolar Protein Sorting 13A (VPS13A gene, which is conserved from yeast to human. The consequences of VPS13A dysfunction in the nervous system are still largely unspecified. In order to study the consequences of VPS13A protein dysfunction in the ageing central nervous system we characterized a Drosophila melanogaster Vps13 mutant line. The Drosophila Vps13 gene encoded a protein of similar size as human VPS13A. Our data suggest that Vps13 is a peripheral membrane protein located to endosomal membranes and enriched in the fly head. Vps13 mutant flies showed a shortened life span and age associated neurodegeneration. Vps13 mutant flies were sensitive to proteotoxic stress and accumulated ubiquitylated proteins. Levels of Ref(2P, the Drosophila orthologue of p62, were increased and protein aggregates accumulated in the central nervous system. Overexpression of the human Vps13A protein in the mutant flies partly rescued apparent phenotypes. This suggests a functional conservation of human VPS13A and Drosophila Vps13. Our results demonstrate that Vps13 is essential to maintain protein homeostasis in the larval and adult Drosophila brain. Drosophila Vps13 mutants are suitable to investigate the function of Vps13 in the brain, to identify genetic enhancers and suppressors and to screen for potential therapeutic targets for Chorea-Acanthocytosis.

  4. Rings and gaps in the disc around Elias 24 revealed by ALMA

    Science.gov (United States)

    Dipierro, G.; Ricci, L.; Pérez, L.; Lodato, G.; Alexander, R. D.; Laibe, G.; Andrews, S.; Carpenter, J. M.; Chandler, C. J.; Greaves, J. A.; Hall, C.; Henning, T.; Kwon, W.; Linz, H.; Mundy, L.; Sargent, A.; Tazzari, M.; Testi, L.; Wilner, D.

    2018-04-01

    We present Atacama Large Millimeter/sub-millimeter Array (ALMA) Cycle 2 observations of the 1.3-mm dust continuum emission of the protoplanetary disc surrounding the T Tauri star Elias 24 with an angular resolution of ˜0.2 arcsec (˜28 au). The dust continuum emission map reveals a dark ring at a radial distance of 0.47 arcsec (˜65 au) from the central star, surrounded by a bright ring at 0.58 arcsec (˜81 au). In the outer disc, the radial intensity profile shows two inflection points at 0.71 and 0.87 arcsec (˜99 and 121 au, respectively). We perform global three-dimensional smoothed particle hydrodynamic gas/dust simulations of discs hosting a migrating and accreting planet. Combining the dust density maps of small and large grains with three-dimensional radiative transfer calculations, we produce synthetic ALMA observations of a variety of disc models in order to reproduce the gap- and ring-like features observed in Elias 24. We find that the dust emission across the disc is consistent with the presence of an embedded planet with a mass of ˜0.7 MJ at an orbital radius of ˜ 60 au. Our model suggests that the two inflection points in the radial intensity profile are due to the inward radial motion of large dust grains from the outer disc. The surface brightness map of our disc model provides a reasonable match to the gap- and ring-like structures observed in Elias 24, with an average discrepancy of ˜5 per cent of the observed fluxes around the gap region.

  5. Cytoplasmic Streaming in the Drosophila Oocyte.

    Science.gov (United States)

    Quinlan, Margot E

    2016-10-06

    Objects are commonly moved within the cell by either passive diffusion or active directed transport. A third possibility is advection, in which objects within the cytoplasm are moved with the flow of the cytoplasm. Bulk movement of the cytoplasm, or streaming, as required for advection, is more common in large cells than in small cells. For example, streaming is observed in elongated plant cells and the oocytes of several species. In the Drosophila oocyte, two stages of streaming are observed: relatively slow streaming during mid-oogenesis and streaming that is approximately ten times faster during late oogenesis. These flows are implicated in two processes: polarity establishment and mixing. In this review, I discuss the underlying mechanism of streaming, how slow and fast streaming are differentiated, and what we know about the physiological roles of the two types of streaming.

  6. Dying cells protect survivors from radiation-induced cell death in Drosophila.

    Directory of Open Access Journals (Sweden)

    Amber Bilak

    2014-03-01

    Full Text Available We report a phenomenon wherein induction of cell death by a variety of means in wing imaginal discs of Drosophila larvae resulted in the activation of an anti-apoptotic microRNA, bantam. Cells in the vicinity of dying cells also become harder to kill by ionizing radiation (IR-induced apoptosis. Both ban activation and increased protection from IR required receptor tyrosine kinase Tie, which we identified in a genetic screen for modifiers of ban. tie mutants were hypersensitive to radiation, and radiation sensitivity of tie mutants was rescued by increased ban gene dosage. We propose that dying cells activate ban in surviving cells through Tie to make the latter cells harder to kill, thereby preserving tissues and ensuring organism survival. The protective effect we report differs from classical radiation bystander effect in which neighbors of irradiated cells become more prone to death. The protective effect also differs from the previously described effect of dying cells that results in proliferation of nearby cells in Drosophila larval discs. If conserved in mammals, a phenomenon in which dying cells make the rest harder to kill by IR could have implications for treatments that involve the sequential use of cytotoxic agents and radiation therapy.

  7. Semi-automated quantitative Drosophila wings measurements.

    Science.gov (United States)

    Loh, Sheng Yang Michael; Ogawa, Yoshitaka; Kawana, Sara; Tamura, Koichiro; Lee, Hwee Kuan

    2017-06-28

    Drosophila melanogaster is an important organism used in many fields of biological research such as genetics and developmental biology. Drosophila wings have been widely used to study the genetics of development, morphometrics and evolution. Therefore there is much interest in quantifying wing structures of Drosophila. Advancement in technology has increased the ease in which images of Drosophila can be acquired. However such studies have been limited by the slow and tedious process of acquiring phenotypic data. We have developed a system that automatically detects and measures key points and vein segments on a Drosophila wing. Key points are detected by performing image transformations and template matching on Drosophila wing images while vein segments are detected using an Active Contour algorithm. The accuracy of our key point detection was compared against key point annotations of users. We also performed key point detection using different training data sets of Drosophila wing images. We compared our software with an existing automated image analysis system for Drosophila wings and showed that our system performs better than the state of the art. Vein segments were manually measured and compared against the measurements obtained from our system. Our system was able to detect specific key points and vein segments from Drosophila wing images with high accuracy.

  8. Cervical disc hernia operations through posterior laminoforaminotomy.

    Science.gov (United States)

    Yolas, Coskun; Ozdemir, Nuriye Guzin; Okay, Hilmi Onder; Kanat, Ayhan; Senol, Mehmet; Atci, Ibrahim Burak; Yilmaz, Hakan; Coban, Mustafa Kemal; Yuksel, Mehmet Onur; Kahraman, Umit

    2016-01-01

    The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years). Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%). On control examinations, there was no finding of instability or cervical kyphosis. Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  9. Cervical disc hernia operations through posterior laminoforaminotomy

    Directory of Open Access Journals (Sweden)

    Coskun Yolas

    2016-01-01

    Full Text Available Objective: The most common used technique for posterolateral cervical disc herniations is anterior approach. However, posterior cervical laminotoforaminomy can provide excellent results in appropriately selected patients with foraminal stenosis in either soft disc prolapse or cervical spondylosis. The purpose of this study was to present the clinical outcomes following posterior laminoforaminotomy in patients with radiculopathy. Materials and Methods: We retrospectively evaluated 35 patients diagnosed with posterolateral cervical disc herniation and cervical spondylosis with foraminal stenosis causing radiculopathy operated by the posterior cervical keyhole laminoforaminotomy between the years 2010 and 2015. Results: The file records and the radiographic images of the 35 patients were assessed retrospectively. The mean age was 46.4 years (range: 34-66 years. Of the patients, 19 were males and 16 were females. In all of the patients, the neurologic deficit observed was radiculopathy. The posterolaterally localized disc herniations and the osteophytic structures were on the left side in 18 cases and on the right in 17 cases. In 10 of the patients, the disc level was at C5-6, in 18 at C6-7, in 2 at C3-4, in 2 at C4-5, in 1 at C7-T1, in 1 patient at both C5-6 and C6-7, and in 1 at both C4-5 and C5-6. In 14 of these 35 patients, both osteophytic structures and protruded disc herniation were present. Intervertebral foramen stenosis was present in all of the patients with osteophytes. Postoperatively, in 31 patients the complaints were relieved completely and four patients had complaints of neck pain and paresthesia radiating to the arm (the success of operation was 88.5%. On control examinations, there was no finding of instability or cervical kyphosis. Conclusion: Posterior cervical laminoforaminotomy is an alternative appropriate choice in both cervical soft disc herniations and cervical stenosis.

  10. Star-disc interaction in galactic nuclei: formation of a central stellar disc

    Science.gov (United States)

    Panamarev, Taras; Shukirgaliyev, Bekdaulet; Meiron, Yohai; Berczik, Peter; Just, Andreas; Spurzem, Rainer; Omarov, Chingis; Vilkoviskij, Emmanuil

    2018-05-01

    We perform high-resolution direct N-body simulations to study the effect of an accretion disc on stellar dynamics in an active galactic nucleus (AGN). We show that the interaction of the nuclear stellar cluster (NSC) with the gaseous accretion disc (AD) leads to formation of a stellar disc in the central part of the NSC. The accretion of stars from the stellar disc on to the super-massive black hole is balanced by the capture of stars from the NSC into the stellar disc, yielding a stationary density profile. We derive the migration time through the AD to be 3 per cent of the half-mass relaxation time of the NSC. The mass and size of the stellar disc are 0.7 per cent of the mass and 5 per cent of the influence radius of the super-massive black hole. An AD lifetime shorter than the migration time would result in a less massive nuclear stellar disc. The detection of such a stellar disc could point to past activity of the hosting galactic nucleus.

  11. Radiological assessment of loss of disc height during acute and chronic degenerative lumbar disc alterations

    International Nuclear Information System (INIS)

    Zoellner, J.; Sancaktaroglu, T.; Nafe, B.; Eysel, P.; Loew, R.

    2001-01-01

    Aim of the study: A loss of disc height with increasing segmental mobility is an important reason for low back pain. The measurement of hyaluronic acid content of the nucleus pulposus prolaps shows a difference between acute (group 1) and chronic (group 2) disc degeneration. The purpose of the present investigation was to determine the decreasing of disc height between these two groups and the no-symptomatic segments of these patients. Methods: 20 human lateral preoperative X-ray measurements according to Frobin et al. were taken; group 1 with 7 patients (mean age 41 years) and group 2 with 13 patients (mean age 44 years). Results: There was a significant tendency (p=0.091) to a reduction of disc height in group 2 between symptomatic and asymptomatic discs. Conclusion: The used method is not suitable to answer the present question conclusively. (orig.) [de

  12. The bHLH factors Dpn and members of the E(spl complex mediate the function of Notch signalling regulating cell proliferation during wing disc development

    Directory of Open Access Journals (Sweden)

    Beatriz P. San Juan

    2012-05-01

    The Notch signalling pathway plays an essential role in the intricate control of cell proliferation and pattern formation in many organs during animal development. In addition, mutations in most members of this pathway are well characterized and frequently lead to tumour formation. The Drosophila imaginal wing discs have provided a suitable model system for the genetic and molecular analysis of the different pathway functions. During disc development, Notch signalling at the presumptive wing margin is necessary for the restricted activation of genes required for pattern formation control and disc proliferation. Interestingly, in different cellular contexts within the wing disc, Notch can either promote cell proliferation or can block the G1-S transition by negatively regulating the expression of dmyc and bantam micro RNA. The target genes of Notch signalling that are required for these functions have not been identified. Here, we show that the Hes vertebrate homolog, deadpan (dpn, and the Enhancer-of-split complex (E(splC genes act redundantly and cooperatively to mediate the Notch signalling function regulating cell proliferation during wing disc development.

  13. Clues on the Milky Way disc formation from population synthesis simulations

    Science.gov (United States)

    Robin, A. C.; Reylé, C.; Bienaymé, O.; Fernandez-Trincado, J. G.; Amôres, E. B.

    2016-09-01

    In recent years the stellar populations of the Milky Way have been investigated from large scale surveys in different ways, from pure star count analysis to detailed studies based on spectroscopic surveys. While in the former case the data can constrain the scale height and scale length thanks to completeness, they suffer from high correlation between these two values. On the other hand, spectroscopic surveys suffer from complex selection functions which hardly allow to derive accurate density distributions. The scale length in particular has been difficult to be constrained, resulting in discrepant values in the literature. Here, we investigate the thick disc characteristics by comparing model simulations with large scale data sets. The simulations are done from the population synthesis model of Besançon. We explore the parameters of the thick disc (shape, local density, age, metallicity) using a Monte Carlo Markov Chain method to constrain the model free parameters (Robin et al. 2014). Correlations between parameters are limited due to the vast spatial coverage of the used surveys (SDSS + 2MASS). We show that the thick disc was created during a long phase of formation, starting about 12 Gyr ago and finishing about 10 Gyr ago, during which gravitational contraction occurred, both vertically and radially. Moreover, in its early phase the thick disc was flaring in the outskirts. We conclude that the thick disc has been created prior to the thin disc during a gravitational collapse phase, slowed down by turbulence related to a high star formation rate, as explained for example in Bournaud et al. (2009) or Lehnert et al. (2009). Our result does not favor a formation from an initial thin disc thickened later by merger events or by secular evolution of the thin disc. We then study the in-plane distribution of stars in the thin disc from 2MASS and show that the thin disc scale length varies as a function of age, indicating an inside out formation. Moreover, we

  14. DZ Chamaeleontis: a bona fide photoevaporating disc

    Science.gov (United States)

    Canovas, H.; Montesinos, B.; Schreiber, M. R.; Cieza, L. A.; Eiroa, C.; Meeus, G.; de Boer, J.; Ménard, F.; Wahhaj, Z.; Riviere-Marichalar, P.; Olofsson, J.; Garufi, A.; Rebollido, I.; van Holstein, R. G.; Caceres, C.; Hardy, A.; Villaver, E.

    2018-02-01

    Context. DZ Cha is a weak-lined T Tauri star (WTTS) surrounded by a bright protoplanetary disc with evidence of inner disc clearing. Its narrow Hα line and infrared spectral energy distribution suggest that DZ Cha may be a photoevaporating disc. Aims: We aim to analyse the DZ Cha star + disc system to identify the mechanism driving the evolution of this object. Methods: We have analysed three epochs of high resolution optical spectroscopy, photometry from the UV up to the sub-mm regime, infrared spectroscopy, and J-band imaging polarimetry observations of DZ Cha. Results: Combining our analysis with previous studies we find no signatures of accretion in the Hα line profile in nine epochs covering a time baseline of 20 yr. The optical spectra are dominated by chromospheric emission lines, but they also show emission from the forbidden lines [SII] 4068 and [OI] 6300Å that indicate a disc outflow. The polarized images reveal a dust depleted cavity of 7 au in radius and two spiral-like features, and we derive a disc dust mass limit of Mdust 80 MJup) companions are detected down to 0.̋07 ( 8 au, projected). Conclusions: The negligible accretion rate, small cavity, and forbidden line emission strongly suggests that DZ Cha is currently at the initial stages of disc clearing by photoevaporation. At this point the inner disc has drained and the inner wall of the truncated outer disc is directly exposed to the stellar radiation. We argue that other mechanisms like planet formation or binarity cannot explain the observed properties of DZ Cha. The scarcity of objects like this one is in line with the dispersal timescale (≲105 yr) predicted by this theory. DZ Cha is therefore an ideal target to study the initial stages of photoevaporation. Based on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere under ESO programme 097.C-0536. Based on data obtained from the ESO Science Archive Facility under request number 250112.

  15. INJURIES IN DISC GOLF - A DESCRIPTIVE CROSS-SECTIONAL STUDY

    DEFF Research Database (Denmark)

    Rahbek, Martin Amadeus; Nielsen, Rasmus Oestergaard

    2016-01-01

    BACKGROUND: Disc golf is rapidly increasing in popularity and more than two million people are estimated to regularly participate in disc golf activities. Despite this popularity, the epidemiology of injuries in disc golf remains under reported. PURPOSE: The purpose of the present study...... was to investigate the prevalence and anatomic distribution of injuries acquired through disc-golf participation in Danish disc golf players. METHODS: The study was a cross-sectional study conducted on Danish disc-golf players. In May 2015, invitations to complete a web-based questionnaire were spread online via...... social media, and around disc-golf courses in Denmark. The questionnaire included questions regarding disc-golf participation and the characteristics of injuries acquired through disc golf participation. The data was analyzed descriptively. RESULTS: An injury prevalence of 13.3% (95% CI: 6.7% to 19...

  16. MRI findings of traumatic cervical disc herniation

    International Nuclear Information System (INIS)

    Tanaka, Hisato; Kasahara, Takaki; Akiyama, Nanae

    2011-01-01

    In general practice, disc hernia is increasingly being questioned about its relation with traffic injuries. In this study, we examined the image findings of cervical disc herniation for findings indicative of traumatic hernia. In 2008, we examined 35 cases of cervical disc herniation at our hospital by MRI. The patients were divided into two groups; patients with trauma history (19 cases) and those without (16 cases), and their images were compared. Disc herniation in the trauma group showed high intensity at T2, with some of the patients in this group also indicating continuous high intensity of the internal and herniated discs. Traumatic force was found to cause swelling under the laryngeal soft tissue. Cases with further flexion injury showed interspinous ligament hemorrhage. These findings strongly suggest the involvement of injury. But given that some younger patients in the non-trauma group also show high intensity at T2*, attention must be paid not to confuse swelling below the larynx with inflammation of the longus colli muscle. (author)

  17. Active galactic nucleus outflows in galaxy discs

    Science.gov (United States)

    Hartwig, Tilman; Volonteri, Marta; Dashyan, Gohar

    2018-05-01

    Galactic outflows, driven by active galactic nuclei (AGNs), play a crucial role in galaxy formation and in the self-regulated growth of supermassive black holes (BHs). AGN feedback couples to and affects gas, rather than stars, and in many, if not most, gas-rich galaxies cold gas is rotationally supported and settles in a disc. We present a 2D analytical model for AGN-driven outflows in a gaseous disc and demonstrate the main improvements, compared to existing 1D solutions. We find significant differences for the outflow dynamics and wind efficiency. The outflow is energy-driven due to inefficient cooling up to a certain AGN luminosity (˜1043 erg s-1 in our fiducial model), above which the outflow remains momentum-driven in the disc up to galactic scales. We reproduce results of 3D simulations that gas is preferentially ejected perpendicular to the disc and find that the fraction of ejected interstellar medium is lower than in 1D models. The recovery time of gas in the disc, defined as the free-fall time from the radius to which the AGN pushes the ISM at most, is remarkably short, of the order 1 Myr. This indicates that AGN-driven winds cannot suppress BH growth for long. Without the inclusion of supernova feedback, we find a scaling of the BH mass with the halo velocity dispersion of MBH ∝ σ4.8.

  18. Dissecting neural pathways for forgetting in Drosophila olfactory aversive memory.

    Science.gov (United States)

    Shuai, Yichun; Hirokawa, Areekul; Ai, Yulian; Zhang, Min; Li, Wanhe; Zhong, Yi

    2015-12-01

    Recent studies have identified molecular pathways driving forgetting and supported the notion that forgetting is a biologically active process. The circuit mechanisms of forgetting, however, remain largely unknown. Here we report two sets of Drosophila neurons that account for the rapid forgetting of early olfactory aversive memory. We show that inactivating these neurons inhibits memory decay without altering learning, whereas activating them promotes forgetting. These neurons, including a cluster of dopaminergic neurons (PAM-β'1) and a pair of glutamatergic neurons (MBON-γ4>γ1γ2), terminate in distinct subdomains in the mushroom body and represent parallel neural pathways for regulating forgetting. Interestingly, although activity of these neurons is required for memory decay over time, they are not required for acute forgetting during reversal learning. Our results thus not only establish the presence of multiple neural pathways for forgetting in Drosophila but also suggest the existence of diverse circuit mechanisms of forgetting in different contexts.

  19. Adjacent Lumbar Disc Herniation after Lumbar Short Spinal Fusion

    OpenAIRE

    Ninomiya, Koshi; Iwatsuki, Koichi; Ohnishi, Yu-ichiro; Ohkawa, Toshika; Yoshimine, Toshiki

    2014-01-01

    A 70-year-old outpatient presented with a chief complaint of sudden left leg motor weakness and sensory disturbance. He had undergone L4/5 posterior interbody fusion with L3–5 posterior fusions for spondylolisthesis 3 years prior, and the screws were removed 1 year later. He has been followed up for 3 years, and there had been no adjacent segment problems before this presentation. Lumbar magnetic resonance imaging (MRI) showed a large L2/3 disc hernia descending to the L3/4 level. Compared to...

  20. Verification and validation of an actuator disc model

    DEFF Research Database (Denmark)

    Réthoré, Pierre-Elouan; Laan, van der, Paul Maarten; Troldborg, Niels

    2014-01-01

    reduce the computational cost of large wind farm wake simulations. The special case of the actuator disc is successfully validated with an analytical solution for heavily loaded turbines and with a full-rotor computation in computational fluid dynamics. Copyright © 2013 John Wiley & Sons, Ltd....... take any kind of shape discretization, determine the intersectional elements with the computational grid and use the size of these elements to redistribute proportionally the forces. This method can potentially reduce the need for mesh refinement in the region surrounding the rotor and, therefore, also...

  1. Functional variation in the gut microbiome of wild Drosophila populations.

    Science.gov (United States)

    Bost, Alyssa; Martinson, Vincent G; Franzenburg, Soeren; Adair, Karen L; Albasi, Alice; Wells, Martin T; Douglas, Angela E

    2018-05-26

    Most of the evidence that the gut microbiome of animals is functionally variable, with consequences for the health and fitness of the animal host, is based on laboratory studies, often using inbred animals under tightly controlled conditions. It is largely unknown whether these microbiome effects would be evident in outbred animal populations under natural conditions. In this study, we quantified the functional traits of the gut microbiota (metagenome) and host (gut transcriptome) and the taxonomic composition of the gut microorganisms (16S rRNA gene sequence) in natural populations of three mycophagous Drosophila species. Variation in microbiome function and composition was driven principally by the period of sample collection, while host function varied mostly with Drosophila species, indicating that variation in microbiome traits is determined largely by environmental factors, and not host taxonomy. Despite this, significant correlations between microbiome and host functional traits were obtained. In particular, microbiome functions dominated by metabolism were positively associated with host functions relating to gut epithelial turnover. Much of the functional variation in the microbiome could be attributed to variation in abundance of Bacteroidetes, rather than the two other abundant groups, the γ-Proteobacteria or Lactobacillales. We conclude that functional variation in the interactions between animals and their gut microbiome can be detectable in natural populations and, in mycophagous Drosophila, this variation relates primarily to metabolism and homeostasis of the gut epithelium. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  2. Ras promotes cell survival by antagonizing both JNK and Hid signals in the Drosophila eye.

    Science.gov (United States)

    Wu, Yue; Zhuang, Yuan; Han, Min; Xu, Tian; Deng, Kejing

    2009-10-20

    Programmed cell death, or apoptosis, is a fundamental physiological process during normal development or in pathological conditions. The activation of apoptosis can be elicited by numerous signalling pathways. Ras is known to mediate anti-apoptotic signals by inhibiting Hid activity in the Drosophila eye. Here we report the isolation of a new loss-of-function ras allele, rasKP, which causes excessive apoptosis in the Drosophila eye. This new function is likely to be mediated through the JNK pathway since the inhibition of JNK signalling can significantly suppress rasKP-induced apoptosis, whereas the removal of hid only weakly suppresses the phenotype. Furthermore, the reduction of JNK signalling together with the expression of the baculovirus caspase inhibitor p35, which blocks Hid activity, strongly suppresses the rasKP cell death. In addition, we find a strong correlation between rasKP-induced apoptosis in the eye disc and the activation of JNK signalling. In the Drosophila eye, Ras may protect cells from apoptosis by inhibiting both JNK and Hid activities. Surprisingly, reducing Ras activity in the wing, however, does not cause apoptosis but rather affects cell and organ size. Thus, in addition to its requirement for cell viability, Ras appears to mediate different biological roles depending on the developmental context and on the level of its expression.

  3. Limited taste discrimination in Drosophila.

    Science.gov (United States)

    Masek, Pavel; Scott, Kristin

    2010-08-17

    In the gustatory systems of mammals and flies, different populations of sensory cells recognize different taste modalities, such that there are cells that respond selectively to sugars and others to bitter compounds. This organization readily allows animals to distinguish compounds of different modalities but may limit the ability to distinguish compounds within one taste modality. Here, we developed a behavioral paradigm in Drosophila melanogaster to evaluate directly the tastes that a fly distinguishes. These studies reveal that flies do not discriminate among different sugars, or among different bitter compounds, based on chemical identity. Instead, flies show a limited ability to distinguish compounds within a modality based on intensity or palatability. Taste associative learning, similar to olfactory learning, requires the mushroom bodies, suggesting fundamental similarities in brain mechanisms underlying behavioral plasticity. Overall, these studies provide insight into the discriminative capacity of the Drosophila gustatory system and the modulation of taste behavior.

  4. The Drosophila Netrin receptor frazzled/DCC functions as an invasive tumor suppressor

    Directory of Open Access Journals (Sweden)

    Duman-Scheel Molly

    2011-06-01

    Full Text Available Abstract Background Loss of heterozygosity at 18q, which includes the Deleted in Colorectal Cancer (DCC gene, has been linked to many human cancers. However, it is unclear if loss of DCC is the specific underlying cause of these cancers. The Drosophila imaginal discs are excellent systems in which to study DCC function, as it is possible to model human tumors through the generation of somatic clones of cells bearing multiple genetic lesions. Here, these attributes of the fly system were utilized to investigate the potential tumor suppressing functions of the Drosophila DCC homologue frazzled (fra during eye-antennal disc development. Results Most fra loss of function clones are eliminated during development. However, when mutant clone cells generated in the developing eye were rescued from death, partially differentiated eye cells were found outside of the normal eye field, and in extreme cases distant sites of the body. Characterization of these cells during development indicates that fra mutant cells display characteristics of invasive tumor cells, including increased levels of phospho-ERK, phospho-JNK, and Mmp-1, changes in cadherin expression, remodeling of the actin cytoskeleton, and loss of polarity. Mutation of fra promotes basement membrane degradation and invasion which are repressed by inhibition of Rho1 signaling. Although inhibition of JNK signaling blocks invasive phenotypes in some metastatic cancer models in flies, blocking JNK signaling inhibits fra mutant cell death, thereby enhancing the fra mutant phenotype. Conclusions The results of this investigation provide the first direct link between point mutations in fra/DCC and metastatic phenotypes in an animal model and suggest that Fra functions as an invasive tumor suppressor during Drosophila development.

  5. Studies on Drosophila radiosensitive strains

    International Nuclear Information System (INIS)

    Varentsova, E.P.; Zakharov, I.A.

    1976-01-01

    45 of radiosensitive strains of Drosophila melanogaster were isolated by Curly/Lobe technique after EMS treatment of Livadia population males. The lethality of non-Curly late larvae after gamma-irradiation (4000r) characterized radiosensitivity strains. Most of them exhibited higher frequency of the spontaneous dominant lethals (up to 69%). The males of 6 strains were semi-sterile. 5 of these strains exhibited higher frequency of X-chromosome non-disjunction

  6. Olfactory memory traces in Drosophila

    OpenAIRE

    Berry, Jacob; Krause, William C.; Davis, Ronald L.

    2008-01-01

    In Drosophila the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons’ response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed...

  7. Hox gene regulation in the central nervous system of Drosophila

    Directory of Open Access Journals (Sweden)

    Maheshwar eGummalla

    2014-04-01

    Full Text Available Hox genes specify the structures that form along the anteroposterior (AP axis of bilateria. Within the genome, they often form clusters where, remarkably enough, their position within the clusters reflects the relative positions of the structures they specify along the AP axis. This correspondence between genomic organization and gene expression pattern has been conserved through evolution and provides a unique opportunity to study how chromosomal context affects gene regulation. In Drosophila, a general rule, often called posterior dominance, states that Hox genes specifying more posterior structures repress the expression of more anterior Hox genes. This rule explains the apparent spatial complementarity of Hox gene expression patterns in Drosophila. Here we review a noticeable exception to this rule where the more-posteriorly expressed Abd-B hox gene fails to repress the more-anterior abd-A gene in cells of the central nervous system (CNS. While Abd-B is required to repress ectopic expression of abd-A in the posterior epidermis, abd-A repression in the posterior CNS is accomplished by a different mechanism that involves a large 92kb long non-coding RNA (lncRNA encoded by the intergenic region separating abd-A and Abd-B (the iab8ncRNA. Dissection of this lncRNA revealed that abd-A is repressed by the lncRNA using two redundant mechanisms. The 1st mechanism is mediated by a microRNA (mir-iab-8 encoded by intronic sequence within the large iab8-ncRNA. Meanwhile, the second mechanism seems to involve transcriptional interference by the long iab-8 ncRNA on the abd-A promoter. Recent work demonstrating CNS-specific regulation of genes by ncRNAs in Drosophila, seem to highlight a potential role for the iab-8-ncRNA in the evolution of the Drosophila hox complexes

  8. Identification of the Drosophila skpA gene as a novel target of the transcription factor DREF

    International Nuclear Information System (INIS)

    Dang Thi Phuong Thao; Ida, Hiroyuki; Yoshida, Hideki; Yamaguchi, Masamitsu

    2006-01-01

    SKPa is component of a Drosophila SCF complex that functions in combination with the ubiquitin-conjugating enzyme UbcD1. skpA null mutation results in centrosome overduplication, unusual chromatin condensation, defective endoreduplication and cell-cycle progression. While the molecular mechanisms that regulate expression of the skpA gene are poorly understood, the DNA replication-related element (DRE) and the DRE-binding factor (DREF) play important roles in regulating proliferation-related genes in Drosophila and DRE (5'-TATCGATA) and DRE-like (5'-CATCGATT) sequences were here found to be involved in skpA promoter activity. Thus both luciferase transient expression assays in cultured Drosophila S2 cells using skpA promoter-luciferase fusion plasmids and anti-lacZ immunostaining of various tissues from transgenic third instar larvae carrying the skpA promoter-lacZ fusion genes provided supportive evidence. Furthermore, anti-SKPa immunostaining of eye imaginal discs from flies overexpressing DREF showed ectopic expression of protein in the region posterior to the morphogenetic furrow where DREF is overexpressed. Knockdown of DREF in some tissues where SKPa distribution is well known almost completely abrogated the skpA gene expression. These findings, taken together, indicate that the Drosophila skpA gene is a novel target of the transcription factor DREF

  9. Drosophila: Retrotransposons Making up Telomeres.

    Science.gov (United States)

    Casacuberta, Elena

    2017-07-19

    Drosophila and extant species are the best-studied telomerase exception. In this organism, telomere elongation is coupled with targeted retrotransposition of Healing Transposon (HeT-A) and Telomere Associated Retrotransposon (TART) with sporadic additions of Telomere Associated and HeT-A Related (TAHRE), all three specialized non-Long Terminal Repeat (non-LTR) retrotransposons. These three very special retroelements transpose in head to tail arrays, always in the same orientation at the end of the chromosomes but never in interior locations. Apparently, retrotransposon and telomerase telomeres might seem very different, but a detailed view of their mechanisms reveals similarities explaining how the loss of telomerase in a Drosophila ancestor could successfully have been replaced by the telomere retrotransposons. In this review, we will discover that although HeT-A, TART, and TAHRE are still the only examples to date where their targeted transposition is perfectly tamed into the telomere biology of Drosophila, there are other examples of retrotransposons that manage to successfully integrate inside and at the end of telomeres. Because the aim of this special issue is viral integration at telomeres, understanding the base of the telomerase exceptions will help to obtain clues on similar strategies that mobile elements and viruses could have acquired in order to ensure their survival in the host genome.

  10. Optogenetic pacing in Drosophila melanogaster

    Science.gov (United States)

    Alex, Aneesh; Li, Airong; Tanzi, Rudolph E.; Zhou, Chao

    2015-01-01

    Electrical stimulation is currently the gold standard for cardiac pacing. However, it is invasive and nonspecific for cardiac tissues. We recently developed a noninvasive cardiac pacing technique using optogenetic tools, which are widely used in neuroscience. Optogenetic pacing of the heart provides high spatial and temporal precisions, is specific for cardiac tissues, avoids artifacts associated with electrical stimulation, and therefore promises to be a powerful tool in basic cardiac research. We demonstrated optogenetic control of heart rhythm in a well-established model organism, Drosophila melanogaster. We developed transgenic flies expressing a light-gated cation channel, channelrhodopsin-2 (ChR2), specifically in their hearts and demonstrated successful optogenetic pacing of ChR2-expressing Drosophila at different developmental stages, including the larva, pupa, and adult stages. A high-speed and ultrahigh-resolution optical coherence microscopy imaging system that is capable of providing images at a rate of 130 frames/s with axial and transverse resolutions of 1.5 and 3.9 μm, respectively, was used to noninvasively monitor Drosophila cardiac function and its response to pacing stimulation. The development of a noninvasive integrated optical pacing and imaging system provides a novel platform for performing research studies in developmental cardiology. PMID:26601299

  11. 'Peer pressure' in larval Drosophila?

    Science.gov (United States)

    Niewalda, Thomas; Jeske, Ines; Michels, Birgit; Gerber, Bertram

    2014-06-06

    Understanding social behaviour requires a study case that is simple enough to be tractable, yet complex enough to remain interesting. Do larval Drosophila meet these requirements? In a broad sense, this question can refer to effects of the mere presence of other larvae on the behaviour of a target individual. Here we focused in a more strict sense on 'peer pressure', that is on the question of whether the behaviour of a target individual larva is affected by what a surrounding group of larvae is doing. We found that innate olfactory preference of a target individual was neither affected (i) by the level of innate olfactory preference in the surrounding group nor (ii) by the expression of learned olfactory preference in the group. Likewise, learned olfactory preference of a target individual was neither affected (iii) by the level of innate olfactory preference of the surrounding group nor (iv) by the learned olfactory preference the group was expressing. We conclude that larval Drosophila thus do not take note of specifically what surrounding larvae are doing. This implies that in a strict sense, and to the extent tested, there is no social interaction between larvae. These results validate widely used en mass approaches to the behaviour of larval Drosophila. © 2014. Published by The Company of Biologists Ltd.

  12. Jamming Transition: Heptagons, Pentagons, and Discs

    Directory of Open Access Journals (Sweden)

    Xu Yuanyuan

    2017-01-01

    Full Text Available The jamming behavior of a system composed of discs has been well documented. However, it remains unclear how a granular system consisting of non-spherical particles transitions between unjammed and jammed states. Here, we present compression experiments to study the jamming transition of 2D granular materials composed of photoelastic heptagonal particles and compare these results to data for discs and pentagons. We determine the critical packing fraction of heptagons and make a comparison to discs and pentagons. In the experiment, we subject 618 heptagonal particles to cyclic compression. We track the motion (inlcuding rotations of the particles, and we measure forces on particles by photoelasticity. We observe a power law relationship between the average contact number (Z and the pressure (P. Furthermore, we classify the type of contacts by the relative orientation of pairs of contacting particles (creating point-to-face and face-to-face contacts, and we explore the evolution of the contacts during jamming.

  13. On the formation of exponential discs

    International Nuclear Information System (INIS)

    Yoshii, Yuzuru; Sommer-Larsen, Jesper

    1989-01-01

    Spiral galaxy discs are characterized by approximately exponential surface luminosity profiles. In this paper the evolutionary equations for a star-forming, viscous disc are solved analytically or semi-analytically. It is shown that approximately exponential stellar surface density profiles result if the viscous time-scale t ν is comparable to the star-formation time scale t * everywhere in the disc. The analytical solutions are used to illuminate further on the issue of why the above mechanism leads to resulting exponential stellar profiles under certain conditions. The sensitivity of the solution to variations of various parameters are investigated and show that the initial gas surface density distribution has to be fairly regular in order that final exponential stellar surface density profiles result. (author)

  14. Optic disc pit with sectorial retinitis pigmentosa.

    Science.gov (United States)

    Balikoglu-Yilmaz, Melike; Taskapili, Muhittin; Yilmaz, Tolga; Teke, Mehmet Yasin

    2013-01-01

    Sectorial retinitis pigmentosa (RP) and optic disc pit (ODP) are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, fluorescein angiography, and multifocal electroretinogram scans confirmed these clinical findings. Visual acuity was decreased due to an atrophic-appearing foveal lesion. No intervention was suggested because of the poor visual potential. To the best of our knowledge, the present study is the first to describe coexistent optic disc pit and sectorial RP in the superior and inferotemporal sectors covering the macula in the same eye with figures.

  15. Optic Disc Pit with Sectorial Retinitis Pigmentosa

    Directory of Open Access Journals (Sweden)

    Melike Balikoglu-Yilmaz

    2013-01-01

    Full Text Available Sectorial retinitis pigmentosa (RP and optic disc pit (ODP are rare clinical conditions. We present a 40-year-old woman with a history of mild night blindness and decreased vision in the right eye for about 5 years. Fundus examination revealed retinal pigmentary changes in the superior and inferotemporal sectors covering the macula and reduced arterial calibre and ODP at the temporal edge of the optic disc. In addition, fundus autofluorescence, spectral-domain optical coherence tomography, fluorescein angiography, and multifocal electroretinogram scans confirmed these clinical findings. Visual acuity was decreased due to an atrophic-appearing foveal lesion. No intervention was suggested because of the poor visual potential. To the best of our knowledge, the present study is the first to describe coexistent optic disc pit and sectorial RP in the superior and inferotemporal sectors covering the macula in the same eye with figures.

  16. M6-C artificial disc placement.

    Science.gov (United States)

    Coric, Domagoj; Parish, John; Boltes, Margaret O

    2017-01-01

    There has been a steady evolution of cervical total disc replacement (TDR) devices over the last decade resulting in surgical technique that closely mimics anterior cervical discectomy and fusion as well as disc design that emphasizes quality of motion. The M6-C TDR device is a modern-generation artificial disc composed of titanium endplates with tri-keel fixation as well as a polyethylene weave with a polyurethane core. Although not yet approved by the FDA, M6-C has finished a pilot and pivotal US Investigational Device Exemption (IDE) study. The authors present the surgical technique for implantation of a 2-level M6-C cervical TDR device. The video can be found here: https://youtu.be/rFEAqINLRCo .

  17. Calcification of intervertebral discs in children

    International Nuclear Information System (INIS)

    Hoermann, D.

    1984-01-01

    Thirteen children with intervertebral disc calcifications of the cervical, thoracal and lumbar spine have been diagnosed since 1970. Most of them were observed over a period of several years. Ten children fell ill with acute pains, but only 2 of them sufferred from a trauma. In 3 cases the features were discovered accidentally combined with malformations of vertebral bodies and congenital diseases. Our results suggest a primary structural inferiority of the calcified discs. The calcifications arise partially from a birth trauma, partially from an unknown etiology. They can last for a long time without symptoms. An acute event effects the pains due to shifting or herniation of calcified disc-fragments. Secondary findings such as decrease of the height of cervical vertebral bodies or destructions of the endplates of thoracal and lumbar vertebral bodies disappear retarded and often incompletely and demand a control for a long time. (orig.)

  18. Identification and characterization of novel natural pathogen of Drosophila melanogaster isolated from wild captured Drosophila spp.

    Science.gov (United States)

    Singh, Karan; Zulkifli, Mohammad; Prasad, N G

    2016-12-01

    Drosophila melanogaster is an emerging model system for the study of evolutionary ecology of immunity. However, a large number of studies have used non natural pathogens as very few natural pathogens have been isolated and identified. Our aim was to isolate and characterize natural pathogen/s of D. melanogaster. A bacterial pathogen was isolated from wild caught Drosophila spp., identified as a new strain of Staphylococcus succinus subsp. succinus and named PK-1. This strain induced substantial mortality (36-62%) in adults of several laboratory populations of D. melanogaster. PK-1 grew rapidly within the body of the flies post infection and both males and females had roughly same number of colony forming units. Mortality was affected by mode of infection and dosage of the pathogen. However mating status of the host had no effect on mortality post infection. Given that there are very few known natural bacterial pathogens of D. melanogaster and that PK-1 can establish a sustained infection across various outbred and inbred populations of D. melanogaster this new isolate is a potential resource for future studies on immunity. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  19. Dippers and dusty disc edges: new diagnostics and comparison to model predictions

    Science.gov (United States)

    Bodman, Eva H. L.; Quillen, Alice C.; Ansdell, Megan; Hippke, Michael; Boyajian, Tabetha S.; Mamajek, Eric E.; Blackman, Eric G.; Rizzuto, Aaron; Kastner, Joel H.

    2017-09-01

    We revisit the nature of large dips in flux from extinction by dusty circumstellar material that is observed by Kepler for many young stars in the Upper Sco and ρ Oph star formation regions. These young, low-mass 'dipper' stars are known to have low accretion rates and primarily host moderately evolved dusty circumstellar discs. Young low-mass stars often exhibit rotating starspots that cause quasi-periodic photometric variations. We found no evidence for periods associated with the dips that are different from the starspot rotation period in spectrograms constructed from the light curves. The material causing the dips in most of these light curves must be approximately corotating with the star. We find that disc temperatures computed at the disc corotation radius are cool enough that dust should not sublime. Crude estimates for stellar magnetic field strengths and accretion rates are consistent with magnetospheric truncation near the corotation radius. Magnetospheric truncation models can explain why the dips are associated with material near corotation and how dusty material is lifted out of the mid-plane to obscure the star that would account for the large fraction of young low-mass stars that are dippers. We propose that variations in disc orientation angle, stellar magnetic field dipole tilt axis and disc accretion rate are underlying parameters accounting for differences in the dipper light curves.

  20. A Drosophila immune response against Ras-induced overgrowth

    Directory of Open Access Journals (Sweden)

    Thomas Hauling

    2014-03-01

    Full Text Available Our goal is to characterize the innate immune response against the early stage of tumor development. For this, animal models where genetic changes in specific cells and tissues can be performed in a controlled way have become increasingly important, including the fruitfly Drosophila melanogaster. Many tumor mutants in Drosophila affect the germline and, as a consequence, also the immune system itself, making it difficult to ascribe their phenotype to a specific tissue. Only during the past decade, mutations have been induced systematically in somatic cells to study the control of tumorous growth by neighboring cells and by immune cells. Here we show that upon ectopic expression of a dominant-active form of the Ras oncogene (RasV12, both imaginal discs and salivary glands are affected. Particularly, the glands increase in size, express metalloproteinases and display apoptotic markers. This leads to a strong cellular response, which has many hallmarks of the granuloma-like encapsulation reaction, usually mounted by the insect against larger foreign objects. RNA sequencing of the fat body reveals a characteristic humoral immune response. In addition we also identify genes that are specifically induced upon expression of RasV12. As a proof-of-principle, we show that one of the induced genes (santa-maria, which encodes a scavenger receptor, modulates damage to the salivary glands. The list of genes we have identified provides a rich source for further functional characterization. Our hope is that this will lead to a better understanding of the earliest stage of innate immune responses against tumors with implications for mammalian immunity.

  1. Appearance of Keplerian discs orbiting Kerr superspinars

    Energy Technology Data Exchange (ETDEWEB)

    Stuchlik, Zdenek; Schee, Jan, E-mail: zdenek.stuchlik@fpf.slu.c, E-mail: jan.schee@fpf.slu.c [Institute of Physics, Faculty of Philosophy and Science, Silesian University in Opava, Bezrucovo nam. 13, Opava (Czech Republic)

    2010-11-07

    We study optical phenomena related to the appearance of Keplerian accretion discs orbiting Kerr superspinars predicted by string theory. The superspinar exterior is described by standard Kerr naked singularity geometry breaking the black hole limit on the internal angular momentum (spin). We construct local photon escape cones for a variety of orbiting sources that enable us to determine the superspinars silhouette in the case of distant observers. We show that the superspinar silhouette depends strongly on the assumed edge where the external Kerr spacetime is joined to the internal spacetime governed by string theory and significantly differs from the black hole silhouette. The appearance of the accretion disc is strongly dependent on the value of the superspinar spin in both their shape and frequency shift profile. Apparent extension of the disc grows significantly with the growing spin, while the frequency shift grows with the descending spin. This behaviour differs substantially from the appearance of discs orbiting black holes enabling thus, at least in principle, to distinguish clearly the Kerr superspinars and black holes. In vicinity of a Kerr superspinar the non-escaped photons have to be separated to those captured by the superspinar and those being trapped in its strong gravitational field leading to self-illumination of the disc that could even influence its structure and cause self-reflection effect of radiation of the disc. The amount of trapped photons grows with descending superspinar spin. We thus can expect significant self-illumination effects in the field of Kerr superspinars with near-extreme spin a {approx} 1.

  2. Measurement of lifespan in Drosophila melanogaster.

    Science.gov (United States)

    Linford, Nancy J; Bilgir, Ceyda; Ro, Jennifer; Pletcher, Scott D

    2013-01-07

    Aging is a phenomenon that results in steady physiological deterioration in nearly all organisms in which it has been examined, leading to reduced physical performance and increased risk of disease. Individual aging is manifest at the population level as an increase in age-dependent mortality, which is often measured in the laboratory by observing lifespan in large cohorts of age-matched individuals. Experiments that seek to quantify the extent to which genetic or environmental manipulations impact lifespan in simple model organisms have been remarkably successful for understanding the aspects of aging that are conserved across taxa and for inspiring new strategies for extending lifespan and preventing age-associated disease in mammals. The vinegar fly, Drosophila melanogaster, is an attractive model organism for studying the mechanisms of aging due to its relatively short lifespan, convenient husbandry, and facile genetics. However, demographic measures of aging, including age-specific survival and mortality, are extraordinarily susceptible to even minor variations in experimental design and environment, and the maintenance of strict laboratory practices for the duration of aging experiments is required. These considerations, together with the need to practice careful control of genetic background, are essential for generating robust measurements. Indeed, there are many notable controversies surrounding inference from longevity experiments in yeast, worms, flies and mice that have been traced to environmental or genetic artifacts(1-4). In this protocol, we describe a set of procedures that have been optimized over many years of measuring longevity in Drosophila using laboratory vials. We also describe the use of the dLife software, which was developed by our laboratory and is available for download (http://sitemaker.umich.edu/pletcherlab/software). dLife accelerates throughput and promotes good practices by incorporating optimal experimental design, simplifying

  3. Observing the On-going Formation of Planets and its Effects on Their Parent Discs

    Science.gov (United States)

    Willson, Matthew Alexander

    2017-06-01

    immediately outside of a ring of dusty material largely responsible for the NIR comment of the disc SED, similar to TW Hya b located in a shallow gap in the dust disc outside another ring of over-dense dusty material which bounds a deep but narrow gap. Both of these companion candidates maybe migrating cores which are feeding from the enriched ring of material. I conducted a more extensive study of the pre-transitional disc, V1247 Ori, covering three epochs and the H-, K- and L-wavebands. Complementary observations with VLT/SPHERE in Hα and continuum plus SMA observations in CO (2-1) and continuum were performed. The orientation and geometry of the outer disc was recovered with the SMA data and determine the direction of rotation. We image the inner rim of the outer disc in L-band SAM data, recovering the rim in all three epochs. Combining all three data sets together we form a detailed image of the rim. In H- and K-band SAM data we observe the motion of a close-in companion candidate. This motion was found to be too large to be adequately explained through a near-circular Keplerian orbit within the plane of the disc around the central star. Hence an alternate hypothesis had to be developed. I postulated that the fitted position of the companion maybe influenced by the emission from the disc rim seen in the L-band SAM data. I constructed a suite of model SAM data sets of a companion and a disc rim and found that under the right conditions the fitted separation of a companion will be larger than the true separation. Under these conditions we find the motion of the companion candidate to be consistent with a near-circular Keplerian orbit within the plane of the disc at a semi-major axis of ˜6 au. The Hα data lack the necessary resolution to confirm the companion as an accreting body, but through the high contrast sensitivities enabled by the state of the art SPHERE instrument I was able to rule out any other accreting body within the gap, unless deeply embedded by the sparse

  4. Actuator disc edge singularity. The key to a revised actuator disc concept and momentum theory

    Energy Technology Data Exchange (ETDEWEB)

    Kuik, G.A.M. van (The Wind Energy Group of the Technical University Eindhoven (NL))

    1989-01-01

    Since the beginning of rotor aerodynamics the actuator disc momentum theory occupies a prominant place in almost any textbook on this subject. Specially in axial flow the theory provides an easy and rather accurate performance prediction. The results first obtained by Lanchester for the induced power of a hovering rotor and the maximum power of a wind turbine are still used as guidelines for complicated calculations. On the other hand, experimental results for propellers are known to deviate systematically (some 10%) from the momentum theory results. This is commonly attributed to the differences between a real rotor and an actuator disc. However, some actuator disc- and actuator strip (the 2-dimensional version) experiments are described in literature, showing the same deviations from momentum theory results. Therefore, apart from the question how representative an actuator disc is for a real rotor, the actuator disc concept itself may be inadequate. This problem is the subject of the work describe here. It will be shown that the classical actuator disc concept ignores discrete forces resulting from a flow singularity at the edge of the disc. The (extended) momentum theory, applied to this actuator strip model, shows a shift of the results towards the experimental data, and for the static case (hover) even a quantitative agreement is obtained. (author) 12 refs.

  5. Disc valve for sampling erosive process streams

    Science.gov (United States)

    Mrochek, J.E.; Dinsmore, S.R.; Chandler, E.W.

    1986-01-07

    A four-port disc valve is described for sampling erosive, high temperature process streams. A rotatable disc defining opposed first and second sampling cavities rotates between fired faceplates defining flow passageways positioned to be alternatively in axial alignment with the first and second cavities. Silicon carbide inserts and liners composed of [alpha] silicon carbide are provided in the faceplates and in the sampling cavities to limit erosion while providing lubricity for a smooth and precise operation when used under harsh process conditions. 1 fig.

  6. Static axisymmetric discs and gravitational collapse

    Energy Technology Data Exchange (ETDEWEB)

    Chamorro, A.; Gregory, R.; Stewart, J.M.

    1987-09-08

    Regular static axisymmetric vacuum solutions of Einstein's field equations representing the exterior field of a finite thin disc are found. These are used to describe the slow collapse of a disc-like object. If no conditions are placed on the matter, a naked singularity is formed and the cosmic censorship hypothesis would be violated. Imposition of the weak energy condition, however, prevents slow collapse to a singularity and preserves the validity of this hypothesis. The validity of the hoop conjecture is also discussed.

  7. Cells and Biomaterials for Intervertebral Disc Regeneration

    CERN Document Server

    Grad, Sibylle

    2010-01-01

    Disorders related to the intervertebral disc (IVD) are common causes of morbidity and of severe life quality deterioration. IVD degeneration, although in many cases asymptomatic, is often the origin of painful neck and back diseases. In Western societies IVD related pain and disability account for enormous health care costs as a result of work absenteeism and thus lost production, disability benefits, medical and insurance expenses. Although only a small percentage of patients with disc disorders finally will undergo surgery, spinal surgery has been one of the fastest growing disciplines in th

  8. Radioresistance and radiosensitivity in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Reguly, M.L.

    1983-01-01

    Studying the mechanisms controlling radioresistant in Drosophila the sensibility of four strains of Drosophila melanogaster to sex-linked recessive lethal mutations induced by 5kR Cobalt-60 gamma radiation and 0,006 M EMS or 0,25% of caffeine was determined. (M.A.C.) [pt

  9. The Drosophila melanogaster circadian pacemaker circuit

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Keywords. circadian rhythm; neuronal network; ion channel; behaviour; neurotransmitter; electrophysiology; Drosophila. Abstract. As an experimental model system, the fruit fly Drosophila melanogaster has been seminal in shaping our understanding of the circadian clockwork. The wealth of genetic tools ...

  10. Mechanical Characterization of the Human Lumbar Intervertebral Disc Subjected to Impact Loading Conditions

    Science.gov (United States)

    Jamison, David, IV

    Low back pain is a large and costly problem in the United States. Several working populations, such as miners, construction workers, forklift operators, and military personnel, have an increased risk and prevalence of low back pain compared to the general population. This is due to exposure to repeated, transient impact shocks, particularly while operating vehicles or other machinery. These shocks typically do not cause acute injury, but rather lead to pain and injury over time. The major focus in low back pain is often the intervertebral disc, due to its role as the major primary load-bearing component along the spinal column. The formation of a reliable standard for human lumbar disc exposure to repeated transient shock could potentially reduce injury risk for these working populations. The objective of this project, therefore, is to characterize the mechanical response of the lumbar intervertebral disc subjected to sub-traumatic impact loading conditions using both cadaveric and computational models, and to investigate the possible implications of this type of loading environment for low back pain. Axial, compressive impact loading events on Naval high speed boats were simulated in the laboratory and applied to human cadaveric specimen. Disc stiffness was higher and hysteresis was lower than quasi-static loading conditions. This indicates a shift in mechanical response when the disc is under impact loads and this behavior could be contributing to long-term back pain. Interstitial fluid loss and disc height changes were shown to affect disc impact mechanics in a creep study. Neutral zone increased, while energy dissipation and low-strain region stiffness decreased. This suggests that the disc has greater clinical instability during impact loading with progressive creep and fluid loss, indicating that time of day should be considered for working populations subjected to impact loads. A finite element model was developed and validated against cadaver specimen

  11. Influence of the fin orientation on the cooling of disc-brakes

    International Nuclear Information System (INIS)

    Abanto, J.; Reggio, M.

    2003-01-01

    Nowadays, computational fluid dynamics is being applied in many fronts to improve the understanding of the flow and heat transfer behaviour in engineering applications. Unfortunately, there are not so many computational investigations regarding the ventilation and temperature distribution in discs-brakes. In this respect, this study presents a (CFD) analysis is carried out to investigate temperature distributions and flow patterns through disc brakes. The final goal is the development of shapes that optimize heat dissipation rates dictating the stopping capability of disc brakes. High performance discs brakes have a variety of cooling channels and the optimization of these passages is a challenging task for the manufacturing industry. High values of heat transfer coefficients of disc-brake configurations, are the most critical quantities during the design phase of new braking systems. In this context, a parametric study of the influence of the fin orientation concerning the cooling process of the rotating disc-brakes is presented. The numerical simulation was performed using four different solid configurations with the same weight, material properties and boundary conditions. In order to keep constant the influence of the numerical diffusion, these forms have been inserted in the fixed far computational domain (more than 90% of the overall domain). This large transient conjugate heat transfer analysis has been performed following the standard Fade and Recovery procedures. These allows to evaluate the heat dissipation and the evolution of heat transfer coefficients in space and time for each idealized brake model. Relevant temperature variations have been observed during the braking process when compared to the baseline disc-brake model. A commercial finite-volume based code was used for this CFD application. Mass, momentum, energy and K - ε RNG turbulence equations have been solved. (author)

  12. DISC1 and striatal volume: a potential risk phenotype for mental illness

    Directory of Open Access Journals (Sweden)

    M. Mallar eChakravarty

    2012-06-01

    Full Text Available Disrupted-in-schizophrenia 1 was originally discovered in a large Scottish family with abnormally high rates of severe mental illness, including schizophrenia, bipolar disorder, and depression. An accumulating body of evidence from genetic, postmortem, and animal data supports a role for DISC1 in different forms of mental illness. DISC1 may play an important role in determining structure and function of several brain regions. One brain region of particular importance for several mental disorders is the striatum, and DISC1 mutant mice have demonstrated an increase in dopamine (D2 receptors in this structure. However, association between DISC1 functional polymorphisms and striatal structure have not been examined in humans to our knowledge. We, therefore hypothesized that there would be a relationship between human striatal volume and DISC1 genotype, specifically in the Leu607Phe (rs6675281 and Ser704Cys (rs821618 single nucleotide polymorphisms. We tested our hypothesis by automatically identifying the striatum in fifty-four healthy volunteers recruited for this study. We also performed an exploratory analysis of cortical thickness, cortical surface area, and structure volume. Our results demonstrate that Phe allele carriers have larger striatal volume bilaterally (left striatum: p=0.017; right striatum: p=0.016. From the exploratory analyses we found that Phe carriers also had larger right hemisphere volumes and right occipital lobe surface area (p=0.014 compared to LeuLeu homozygotes (p=0.0074. However, these exploratory findings do not survive a conservative correction for multiple comparisons. Our findings demonstrate that a functional DISC1 variant influences striatal volumes. Taken together with animal data that this gene influences D2 receptor levels in striatum, a key risk pathway for mental illnesses such as schizophrenia and bipolar disorder may be conferred via DISC1’s effects on the striatum .

  13. Host-microbe interactions in the gut of Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Takayuki eKuraishi

    2013-12-01

    Full Text Available Many insect species subsist on decaying and contaminated matter and are thus exposed to large quantities of microorganisms. To control beneficial commensals and combat infectious pathogens, insects must be armed with efficient systems for microbial recognition, signaling pathways, and effector molecules. The molecular mechanisms regulating these host-microbe interactions in insects have been largely clarified in Drosophila melanogaster with its powerful genetic and genomic tools. Here we review recent advances in this field, focusing mainly on the relationships between microbes and epithelial cells in the intestinal tract where the host exposure to the external environment is most frequent.

  14. Relationship of condylar position to disc position and morphology

    Energy Technology Data Exchange (ETDEWEB)

    Incesu, L.; Taskaya-Yilmaz, N. E-mail: nergizy@omu.edu.tr; Oeguetcen-Toller, M.; Uzun, E

    2004-09-01

    Introduction/objective: The purpose of this study was to assess whether condylar position, as depicted by magnetic resonance imaging, was an indicator of disc morphology and position. Methods and material: One hundred and twenty two TMJs of 61 patients with temporomandibular joint disorder were examined. Condylar position, disc deformity and degree of anterior disc displacement were evaluated by using magnetic resonance imaging. Results and discussion: Posterior condyle position was found to be the main feature of temporomandibular joints with slight and moderate anterior disc displacement. No statistical significance was found between the condylar position, and reducing and nonreducing disc positions. On the other hand, superior disc position was found to be statistically significant for centric condylar position. Conclusion: It was concluded that posterior condyle position could indicate anterior disc displacement whereas there was no relation between the position of condyle and the disc deformity.

  15. Imaging characteristics of noncontained migrating disc fragment and cyst

    International Nuclear Information System (INIS)

    Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G.; Loon, J. van; Calenbergh, F. van

    2001-01-01

    The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

  16. Imaging characteristics of noncontained migrating disc fragment and cyst

    Energy Technology Data Exchange (ETDEWEB)

    Eerens, I.; Demaerel, P.; Haven, F.; Wilms, G. [Dept. of Radiology, University Hospitals, Leuven (Belgium); Loon, J. van; Calenbergh, F. van [Dept. of Neurosurgery, University Hospitals, Leuven (Belgium)

    2001-05-01

    The purpose of this article is to review less common presentations of degenerative disc disease on MR imaging. The images of eight patients were retrospectively analyzed. Six of them had transligamentous (or noncontained) disc herniations, the fragments of which were located in the posterior epidural space in three of them. One patient had a transdural disc fragment and one patient had a disc cyst. The cyst was located in the ventrolateral epidural space. On T2-weighted images, the migrated disc fragment returned a higher signal than the disc of origin in 6 of 7 patients. The disc cyst returned a signal similar to that of cerebrospinal fluid. The MR appearances of disc fragments can be puzzling, particularly if they are located in the posterior epidural space. It is important to recognize the abnormalities in order to differentiate them from less common lesions such as hematoma, abscess and neurinoma. (orig.)

  17. Electrophysiological Recordings from Lobula Plate Tangential Cells in Drosophila.

    Science.gov (United States)

    Mauss, Alex S; Borst, Alexander

    2016-01-01

    Drosophila has emerged as an important model organism for the study of the neural basis of behavior. Its main asset is the experimental accessibility of identified neurons by genetic manipulation and physiological recordings. Drosophila therefore offers the opportunity to reach an integrative understanding of the development and neural underpinnings of behavior at all processing stages, from sensing to motor control, in a single species. Here, we will provide an account of the procedures involved in recording the electrical potential of individual neurons in the visual system of adult Drosophila using the whole-cell patch-clamp method. To this end, animals are fixed to a holder and mounted below a recording chamber. The head capsule is cut open and the glial sheath covering the brain is ruptured by a combination of shearing and enzymatic digest. Neuronal somata are thus exposed and targeted by low-resistance patch electrodes. After formation of a high resistance seal, electrical access to the cell is gained by small current pulses and suction. Stable recordings of large neurons are feasible for >1 h and can be combined with controlled visual stimulation as well as genetic and pharmacological manipulation of upstream circuit elements to infer circuit function in great detail.

  18. Expression of lumican related to CD34 and VEGF in the articular disc of the human temporomandibular joint.

    Directory of Open Access Journals (Sweden)

    N. Kiga

    2010-07-01

    Full Text Available Lumican belongs to the small leucine-rich repeat proteoglycan (SLRP gene family and has been reported to exist in the cornea, intervertebral disc and tendon. Lumican plays a significant role in the assembly and regulation of collagen fibres. The human temporomandibular joint (TMJ disc is made up of fibrocartilage with an extracellular matrix (ECM composed of collagen and proteoglycans. The existence and behaviour of lumican have not been studied in the human TMJ disc. Therefore, we used immunohistochemical methods to detect lumican, CD34 and vascular endothelial growth factor (VEGF and histochemical staining with toluidine blue in 13 human TMJ specimens (10 surgically removed and 3 obtained from autopsy. In both normal and deformed discs we observed staining with toluidine blue. We found that the area of metachromasia inside the deformed disc was uneven and expression of lumican was strong in the areas negative for metachromasia. Staining of VEGF and CD34 inside the deformed disc was seen. We confirmed the expression of lumican in the human TMJ disc and showed that a large number of fibroblastlike cells existed in the area of strong lumican expression. These new findings about the behaviour of lumican suggest that it may play a key role in the generation of a new collagen network by fibroblast-like cells.

  19. The Clinical Correlations between Diabetes, Cigarette Smoking and Obesity on Intervertebral Degenerative Disc Disease of the Lumbar Spine.

    Science.gov (United States)

    Jakoi, Ande M; Pannu, Gurpal; D'Oro, Anthony; Buser, Zorica; Pham, Martin H; Patel, Neil N; Hsieh, Patrick C; Liu, John C; Acosta, Frank L; Hah, Raymond; Wang, Jeffrey C

    2017-06-01

    Retrospective analysis of a nationwide private insurance database. Chi-square analysis and linear regression models were utilized for outcome measures. The purpose of this study was to investigate any relationship between lumbar degenerative disc disease, diabetes, obesity and smoking tobacco. Diabetes, obesity, and smoking tobacco are comorbid conditions known to individually have effect on degenerative disc disease. Most studies have only been on a small populous scale. No study has yet to investigate the combination of these conditions within a large patient cohort nor have they reviewed the combination of these conditions on degenerative disc disease. A retrospective analysis of insurance billing codes within the nationwide Humana insurance database was performed, using PearlDiver software (PearlDiver, Inc., Fort Wayne, IN, USA), to identify trends among patients diagnosed with lumbar disc degenerative disease with and without the associated comorbidities of obesity, diabetes, and/or smoking tobacco. Patients billed for a comorbidity diagnosis on the same patient record as the lumbar disc degenerative disease diagnosis were compared over time to patients billed for lumbar disc degenerative disease without a comorbidity. There were no sources of funding for this manuscript and no conflicts of interest. The total number and prevalence of patients (per 10,000) within the database diagnosed with lumbar disc degenerative disease increased by 241.4% and 130.3%, respectively. The subsets of patients within this population who were concurrently diagnosed with either obesity, diabetes, tobacco use, or a combination thereof, was significantly higher than patients diagnosed with lumbar disc degenerative disease alone ( p degenerative disease and smoking rose significantly more than patients diagnosed with lumbar disc degenerative disease and either diabetes or obesity ( p degenerative disease, smoking and obesity rose significantly more than the number of patients

  20. Maternal control of the Drosophila dorsal–ventral body axis

    Science.gov (United States)

    Stein, David S.; Stevens, Leslie M.

    2016-01-01

    The pathway that generates the dorsal–ventral (DV) axis of the Drosophila embryo has been the subject of intense investigation over the previous three decades. The initial asymmetric signal originates during oogenesis by the movement of the oocyte nucleus to an anterior corner of the oocyte, which establishes DV polarity within the follicle through signaling between Gurken, the Drosophila Transforming Growth Factor (TGF)-α homologue secreted from the oocyte, and the Drosophila Epidermal Growth Factor Receptor (EGFR) that is expressed by the follicular epithelium cells that envelop the oocyte. Follicle cells that are not exposed to Gurken follow a ventral fate and express Pipe, a sulfotransferase that enzymatically modifies components of the inner vitelline membrane layer of the eggshell, thereby transferring DV spatial information from the follicle to the egg. These ventrally sulfated eggshell proteins comprise a localized cue that directs the ventrally restricted formation of the active Spätzle ligand within the perivitelline space between the eggshell and the embryonic membrane. Spätzle activates Toll, a transmembrane receptor in the embryonic membrane. Transmission of the Toll signal into the embryo leads to the formation of a ventral-to-dorsal gradient of the transcription factor Dorsal within the nuclei of the syncytial blastoderm stage embryo. Dorsal controls the spatially specific expression of a large constellation of zygotic target genes, the Dorsal gene regulatory network, along the embryonic DV circumference. This article reviews classic studies and integrates them with the details of more recent work that has advanced our understanding of the complex pathway that establishes Drosophila embryo DV polarity. PMID:25124754

  1. Solid angle subtended by two circular discs

    International Nuclear Information System (INIS)

    Gilly, Louis.

    1978-09-01

    Methods of calculation of solid angles, subtended by two circular discs are analysed. Calculus are methodically classified as follow: series development Legendre polynomes, defined integral, elliptic integrals, Bessel integrals, multiple integrals, Monte Carlo method, electrostatic analogy. Applications in Nuclear Physics are added as examples. List of numeric tables completes bibliography [fr

  2. Frictional Torque on a Rotating Disc

    Science.gov (United States)

    Mungan, Carl E.

    2012-01-01

    Resistance to motion often includes a dry frictional term independent of the speed of an object and a fluid drag term varying linearly with speed in the viscous limit. (At higher speeds, quadratic drag can also occur.) Here, measurements are performed for an aluminium disc mounted on bearings that is given an initial twist and allowed to spin…

  3. Fusion around cervical disc prosthesis: case report.

    NARCIS (Netherlands)

    Bartels, R.H.M.A.; Donk, R.

    2005-01-01

    OBJECTIVE AND IMPORTANCE: Cervical arthroplasty is a relatively new method to maintain motion after cervical anterior discectomy. Two cases are presented in which bony fusion occurred around a cervical disc prosthesis. CLINICAL PRESENTATION: A 30-year-old man and a 49-year-old woman underwent a

  4. Can Exercise Positively Influence the Intervertebral Disc?

    NARCIS (Netherlands)

    Belavý, Daniel L.; Albracht, Kirsten; Bruggemann, Gert Peter; Vergroesen, Pieter Paul A; van Dieën, Jaap H.

    2016-01-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a

  5. Radiographic identification of ingested disc batteries

    International Nuclear Information System (INIS)

    Maves, M.D.

    1986-01-01

    Recently, the hazards by posed the accidental ingestion and impaction of small disc batteries have been widely publicized in the medical and lay press. These foreign bodies, when lodged in the esophagus, leak a caustic solution of 26 to 45% sodium or potassium hydroxide which can cause a burn injury to the esophagus in a very short period of time. Because of the considerable clinical morbidity and mortality from this foreign body, it becomes imperative for the radiologist to quickly and accurately identify disc batteries on plain radiographs. This communication offers a series of radiologic signs important in the identification of disc batteries demonstrate a double density shadow due to the bilaminar structure of the battery. On lateral view, the edges of most disc batteries are round and again present a step-off at the junction of the cathode and anode. These findings are differentiated from the more common esophageal foreign body of a coin which does not have a double density on frontal projection, has a much sharper edge and no visible stepoff. (orig.)

  6. Kinematic structures in galactic disc simulations

    NARCIS (Netherlands)

    Roca-F� brega, S.; Romero-Gómez, M.; Figueras, F.; Antoja Castelltort, Teresa; Valenzuela, O.; Henney, W.J.; Torres-Peimbert, S.

    2011-01-01

    N-body and test particle simulations have been used to characterize the stellar streams in the galactic discs of Milky Way type galaxies. Tools such as the second and third order moments of the velocity ellipsoid and clustering methods -EM-WEKA and FoF- allow characterizing these kinematic

  7. Geršgorin discs revisited

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Hall, F.J.; Marsli, R.

    2013-01-01

    Roč. 438, č. 1 (2013), s. 598-603 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : geometric multiplicity * algebra ic multiplicity * Geršgorin disc Subject RIV: BA - General Mathematics Impact factor: 0.983, year: 2013

  8. Functional Interaction between HEXIM and Hedgehog Signaling during Drosophila Wing Development.

    Science.gov (United States)

    Nguyen, Duy; Fayol, Olivier; Buisine, Nicolas; Lecorre, Pierrette; Uguen, Patricia

    2016-01-01

    Studying the dynamic of gene regulatory networks is essential in order to understand the specific signals and factors that govern cell proliferation and differentiation during development. This also has direct implication in human health and cancer biology. The general transcriptional elongation regulator P-TEFb regulates the transcriptional status of many developmental genes. Its biological activity is controlled by an inhibitory complex composed of HEXIM and the 7SK snRNA. Here, we examine the function of HEXIM during Drosophila development. Our key finding is that HEXIM affects the Hedgehog signaling pathway. HEXIM knockdown flies display strong phenotypes and organ failures. In the wing imaginal disc, HEXIM knockdown initially induces ectopic expression of Hedgehog (Hh) and its transcriptional effector Cubitus interuptus (Ci). In turn, deregulated Hedgehog signaling provokes apoptosis, which is continuously compensated by apoptosis-induced cell proliferation. Thus, the HEXIM knockdown mutant phenotype does not result from the apoptotic ablation of imaginal disc; but rather from the failure of dividing cells to commit to a proper developmental program due to Hedgehog signaling defects. Furthermore, we show that ci is a genetic suppressor of hexim. Thus, HEXIM ensures the integrity of Hedgehog signaling in wing imaginal disc, by a yet unknown mechanism. To our knowledge, this is the first time that the physiological function of HEXIM has been addressed in such details in vivo.

  9. Functional Interaction between HEXIM and Hedgehog Signaling during Drosophila Wing Development.

    Directory of Open Access Journals (Sweden)

    Duy Nguyen

    Full Text Available Studying the dynamic of gene regulatory networks is essential in order to understand the specific signals and factors that govern cell proliferation and differentiation during development. This also has direct implication in human health and cancer biology. The general transcriptional elongation regulator P-TEFb regulates the transcriptional status of many developmental genes. Its biological activity is controlled by an inhibitory complex composed of HEXIM and the 7SK snRNA. Here, we examine the function of HEXIM during Drosophila development. Our key finding is that HEXIM affects the Hedgehog signaling pathway. HEXIM knockdown flies display strong phenotypes and organ failures. In the wing imaginal disc, HEXIM knockdown initially induces ectopic expression of Hedgehog (Hh and its transcriptional effector Cubitus interuptus (Ci. In turn, deregulated Hedgehog signaling provokes apoptosis, which is continuously compensated by apoptosis-induced cell proliferation. Thus, the HEXIM knockdown mutant phenotype does not result from the apoptotic ablation of imaginal disc; but rather from the failure of dividing cells to commit to a proper developmental program due to Hedgehog signaling defects. Furthermore, we show that ci is a genetic suppressor of hexim. Thus, HEXIM ensures the integrity of Hedgehog signaling in wing imaginal disc, by a yet unknown mechanism. To our knowledge, this is the first time that the physiological function of HEXIM has been addressed in such details in vivo.

  10. Vascular complications of prosthetic inter-vertebral discs

    OpenAIRE

    Daly, Kevin J.; Ross, E. Raymond S.; Norris, Heather; McCollum, Charles N.

    2006-01-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had e...

  11. Angiogenesis in the degeneration of the lumbar intervertebral disc

    OpenAIRE

    David, Gh; Ciurea, AV; Iencean, SM; Mohan, A

    2010-01-01

    The goal of the study is to show the histological and biochemical changes that indicate the angiogenesis of the intervertebral disc in lumbar intervertebral disc hernia and the existence of epidemiological correlations between these changes and the risk factors of lumbar intervertebral disc hernia, as well as the patient's quality of life (QOL). We have studied 50 patients aged between 18 and 73 years old, who have undergone lumbar intervertebral disc hernia surgery, making fibroblast growth ...

  12. Physical Limitations to Tissue Engineering of Intervertabral Disc Cells

    OpenAIRE

    Kobayashi, Shigeru; Baba, Hisatoshi; Takeno, Kenichi; Miyazaki, Tsuyoshi; Meir, Adam; Urban, Jill

    2010-01-01

    There is increasing interest in the using biological methods to repair degenerate discs. Biological repair depends on the disc maintaining a population of viable and active cells. Adequate nutrition of the disc influences the outcome of such therapies and, hence, must be considered to be a crucial parameter. Therefore, it is very important to maintain an appropriate physicochemical environment to achieve successful disc repair by biological methods and tissue engineering procedures.

  13. Positional and morphologic changes of the temporomandibular joint disc using magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ahn, Hyoun Suk; Cho, Su Beom; Koh, Kwang Joon

    2001-01-01

    To evaluate displacement and morphologic changes of the temporomandibular joint (TMJ) disc in patient with internal derangement using magnetic resonance imaging (MRI). One hundred and forty five MR images of TMJs in 73 patients were evaluated. Positional and morphologic changes of the TMJ disc were assessed. Lateral or medial disc displacement was also evaluated on cornal images. Among 63 discs with anterior disc displacement, 37 discs were assessed as a biconcave disc and 21 as a deformed disc. Rotational disc displacement was observed in 35 disc. Anteromedial disc displacement was observed in 29 discs, and anterolateral direction in 6 discs. Among 35 rotational displacement, 5 biconcave discs and 21 deformed discs were observed. Rotational and sideways displacement of TMJ discs were found to be common and an important aspect of internal derangement. This study also suggests that sagittal and coronal images of the TMJ have complementary abilities for an assessment of joint abnormality

  14. The EGF receptor and notch signaling pathways control the initiation of the morphogenetic furrow during Drosophila eye development.

    Science.gov (United States)

    Kumar, J P; Moses, K

    2001-07-01

    The onset of pattern formation in the developing Drosophila retina begins with the initiation of the morphogenetic furrow, the leading edge of a wave of retinal development that transforms a uniform epithelium, the eye imaginal disc into a near crystalline array of ommatidial elements. The initiation of this wave of morphogenesis is under the control of the secreted morphogens Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless (Wg). We show that the Epidermal Growth Factor Receptor and Notch signaling cascades are crucial components that are also required to initiate retinal development. We also show that the initiation of the morphogenetic furrow is the sum of two genetically separable processes: (1) the 'birth' of pattern formation at the posterior margin of the eye imaginal disc; and (2) the subsequent 'reincarnation' of retinal development across the epithelium.

  15. Grain size segregation in debris discs

    Science.gov (United States)

    Thebault, P.; Kral, Q.; Augereau, J.-C.

    2014-01-01

    Context. In most debris discs, dust grain dynamics is strongly affected by stellar radiation pressure. Because this mechanism is size-dependent, we expect dust grains to be spatially segregated according to their sizes. However, because of the complex interplay between radiation pressure, grain processing by collisions, and dynamical perturbations, this spatial segregation of the particle size distribution (PSD) has proven difficult to investigate and quantify with numerical models. Aims: We propose to thoroughly investigate this problem by using a new-generation code that can handle some of the complex coupling between dynamical and collisional effects. We intend to explore how PSDs behave in both unperturbed discs at rest and in discs pertubed by planetary objects. Methods: We used the DyCoSS code to investigate the coupled effect of collisions, radiation pressure, and dynamical perturbations in systems that have reached a steady-state. We considered two setups: a narrow ring perturbed by an exterior planet, and an extended disc into which a planet is embedded. For both setups we considered an additional unperturbed case without a planet. We also investigated the effect of possible spatial size segregation on disc images at different wavelengths. Results: We find that PSDs are always spatially segregated. The only case for which the PSD follows a standard dn ∝ s-3.5ds law is for an unperturbed narrow ring, but only within the parent-body ring itself. For all other configurations, the size distributions can strongly depart from such power laws and have steep spatial gradients. As an example, the geometrical cross-section of the disc is very rarely dominated by the smallest grains on bound orbits, as it is expected to be in standard PSDs in sq with q ≤ -3. Although the exact profiles and spatial variations of PSDs are a complex function of the set-up that is considered, we are still able to derive some reliable results that will be useful for image or SED

  16. Prognosis of intervertebral disc loss from diagnosis of degenerative disc disease

    Science.gov (United States)

    Li, S.; Lin, A.; Tay, K.; Romano, W.; Osman, Said

    2015-03-01

    Degenerative Disc Disease (DDD) is one of the most common causes of low back pain, and is a major factor in limiting the quality of life of an individual usually as they enter older stages of life, the disc degeneration reduces the shock absorption available which in turn causes pain. Disc loss is one of the central processes in the pathogenesis of DDD. In this study, we investigated whether the image texture features quantified from magnetic resonance imaging (MRI) could be appropriate markers for diagnosis of DDD and prognosis of inter-vertebral disc loss. The main objective is to use simple image based biomarkers to perform prognosis of spinal diseases using non-invasive procedures. Our results from 65 subjects proved the higher success rates of the combination marker compared to the individual markers and in the future, we will extend the study to other spine regions to allow prognosis and diagnosis of DDD for a wider region.

  17. Calibrated Tully-Fisher relations for improved estimates of disc rotation velocities

    NARCIS (Netherlands)

    Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno II, Jim; Lackner, C. N.

    2011-01-01

    In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity V-rot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of V-rot applicable to large galaxy

  18. Putting pressure on the spine : an osmoviscoelastic FE model of the intervertebral disc

    NARCIS (Netherlands)

    Schroder, Y.

    2008-01-01

    Back pain is a frequently occurring complaint in adults, having a relatively large impact on the European economy due to the fact that it often partially incapacitates the patient. Intervertebral discs are believed to be a key element of back pain. Apart from providing flexibility to the spine,

  19. Airfoil data sensitivity analysis for actuator disc simulations used in wind turbine applications

    DEFF Research Database (Denmark)

    Nilsson, Karl; Breton, Simon-Philippe; Sørensen, Jens Nørkær

    2014-01-01

    To analyse the sensitivity of blade geometry and airfoil characteristics on the prediction of performance characteristics of wind farms, large-eddy simulations using an actuator disc (ACD) method are performed for three different blade/airfoil configurations. The aim of the study is to determine ...

  20. On the formation of spiral structure in gas discs through tidal interaction

    International Nuclear Information System (INIS)

    Sorensen, S.A.

    1985-01-01

    This paper investigates the waves which are formed when a thin gas disc in a smooth axisymmetric potential is perturbed. The perturbation is introduced through tidal interaction with an external body moving in the plane of the disc. The model is investigated using numerical techniques which follow the formation of large-scale hyperbolic spirals. These are identified as the propagating fronts of epicyclic waves. Over an area comparable to the visual image of a galaxy the spirals change from the hyperbolic form towards an equiangular appearance. Predictions by analytical models were found to be in good agreement with the results. (author)

  1. A catalog of polychromatic bulge-disc decompositions of ˜17.600 galaxies in CANDELS

    Science.gov (United States)

    Dimauro, Paola; Huertas-Company, Marc; Daddi, Emanuele; Pérez-González, Pablo G.; Bernardi, Mariangela; Barro, Guillermo; Buitrago, Fernando; Caro, Fernando; Cattaneo, Andrea; Dominguez-Sánchez, Helena; Faber, Sandra M.; Häußler, Boris; Kocevski, Dale D.; Koekemoer, Anton M.; Koo, David C.; Lee, Christoph T.; Mei, Simona; Margalef-Bentabol, Berta; Primack, Joel; Rodriguez-Puebla, Aldo; Salvato, Mara; Shankar, Francesco; Tuccillo, Diego

    2018-05-01

    Understanding how bulges grow in galaxies is critical step towards unveiling the link between galaxy morphology and star-formation. To do so, it is necessary to decompose large sample of galaxies at different epochs into their main components (bulges and discs). This is particularly challenging, especially at high redshifts, where galaxies are poorly resolved. This work presents a catalog of bulge-disc decompositions of the surface brightness profiles of ˜17.600 H-band selected galaxies in the CANDELS fields (F160W https://lerma.obspm.fr/huertas/form_CANDELS and will be used for scientific analysis in forthcoming works.

  2. Time Localisation of Surface Defects on Optical Discs

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, M.V.

    Many have experienced problems with their Compact Disc player when a disc with a scratch or a finger print is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localisation...

  3. Time Localisation of Surface Defects on Optical Discs

    DEFF Research Database (Denmark)

    Odgaard, Peter Fogh; Wickerhauser, M.V.

    2004-01-01

    Many have experienced problems with their Compact Disc Player when a disc with a scratch or a fingerprint is tried played. One way to improve the playability of discs with such a defect, is to locate the defect in time and then handle it in a special way. As a consequence this time localization...

  4. Analysis of an Assemblage of Discs Employing Interactive Graphics.

    Science.gov (United States)

    1980-12-01

    facilitate the program’s efficiency. Indeed, the ulsabilitv of tie distinct element method is pred icated on ef f ic ielt Irogramming techniques...paragraphs. Any subsequent user of DISC should not necessarily feel bound to this scheme. 33. At the outset of writing DISC, it was decided that a disc

  5. On the illumination of neutron star accretion discs

    Science.gov (United States)

    Wilkins, D. R.

    2018-03-01

    The illumination of the accretion disc in a neutron star X-ray binary by X-rays emitted from (or close to) the neutron star surface is explored through general relativistic ray tracing simulations. The applicability of the canonical suite of relativistically broadened emission line models (developed for black holes) to discs around neutron stars is evaluated. These models were found to describe well emission lines from neutron star accretion discs unless the neutron star radius is larger than the innermost stable orbit of the accretion disc at 6 rg or the disc is viewed at high inclination, above 60° where shadowing of the back side of the disc becomes important. Theoretical emissivity profiles were computed for accretion discs illuminated by hotspots on the neutron star surfaces, bands of emission and emission by the entirety of the hot, spherical star surface and in all cases, the emissivity profile of the accretion disc was found to be well represented by a single power law falling off slightly steeper than r-3. Steepening of the emissivity index was found where the emission is close to the disc plane and the disc can appear truncated when illuminated by a hotspot at high latitude. The emissivity profile of the accretion disc in Serpens X-1 was measured and found to be consistent with a single unbroken power law with index q=3.5_{-0.4}^{+0.3}, suggestive of illumination by the boundary layer between the disc and neutron star surface.

  6. A method for quantitative measurement of lumbar intervertebral disc structures

    DEFF Research Database (Denmark)

    Tunset, Andreas; Kjær, Per; Samir Chreiteh, Shadi

    2013-01-01

    There is a shortage of agreement studies relevant for measuring changes over time in lumbar intervertebral disc structures. The objectives of this study were: 1) to develop a method for measurement of intervertebral disc height, anterior and posterior disc material and dural sac diameter using MR...

  7. CT in diagnosis of recurrent vertebral disc hernias after preceding lumbar disc prolapse surgery

    International Nuclear Information System (INIS)

    Burval, S.; Nekula, J.; Vaverka, M.; Veliskova, J.

    1992-01-01

    20 patients with recurrent symptoms following operations for disc prolapse and resistant to treatment were studied by CT, using plain and enhanced images. The results have been analysed. In 10 patients a recurrence of disc prolapse was diagnosed, and this was confirmed surgically in 8 cases. In 2 patients there was epidural scarring. The findings indicate that differential diagnosis between scarring and recurring prolapse can by accurately made by this technique. (orig.) [de

  8. The life cycles of Be viscous decretion discs: fundamental disc parameters of 54 SMC Be stars

    Science.gov (United States)

    Rímulo, L. R.; Carciofi, A. C.; Vieira, R. G.; Rivinius, Th; Faes, D. M.; Figueiredo, A. L.; Bjorkman, J. E.; Georgy, C.; Ghoreyshi, M. R.; Soszyński, I.

    2018-05-01

    Be stars are main-sequence massive stars with emission features in their spectrum, which originates in circumstellar gaseous discs. Even though the viscous decretion disc model can satisfactorily explain most observations, two important physical ingredients, namely the magnitude of the viscosity (α) and the disc mass injection rate, remain poorly constrained. The light curves of Be stars that undergo events of disc formation and dissipation offer an opportunity to constrain these quantities. A pipeline was developed to model these events that use a grid of synthetic light curves, computed from coupled hydrodynamic and radiative transfer calculations. A sample of 54 Be stars from the OGLE survey of the Small Magellanic Cloud (SMC) was selected for this study. Because of the way our sample was selected (bright stars with clear disc events), it likely represents the densest discs in the SMC. Like their siblings in the Galaxy, the mass of the disc in the SMC increases with the stellar mass. The typical mass and angular momentum loss rates associated with the disc events are of the order of ˜10-10 M⊙ yr-1 and ˜5 × 1036 g cm2 s-2, respectively. The values of α found in this work are typically of a few tenths, consistent with recent results in the literature and with the ones found in dwarf novae, but larger than current theory predicts. Considering the sample as a whole, the viscosity parameter is roughly two times larger at build-up ( = 0.63) than at dissipation ( = 0.26). Further work is necessary to verify whether this trend is real or a result of some of the model assumptions.

  9. Spontaneous Resolution of Optic Disc Pit Maculopathy

    Directory of Open Access Journals (Sweden)

    Koushik Tripathy

    2017-06-01

    Full Text Available I read with interest the article reporting spontaneous resolution of optic disc pit maculopathy in a boy.1 Though the presence of an optic disc pit and associated macular involvement is undoubted in the presented case, the provided optical coherence tomography (OCT does not clearly show typical intraretinal schisis (Figure 1B1 at multiple retinal levels which may communicate with the pit. Instead, it shows a sub-internal limiting membrane (sub-ILM cavity. Such cavities are known to occur following the resolution of sub-ILM bleed due to various cause including Valsalva retinopathy,2 Terson syndrome, and also in some retinitis3 cases.4 In fact, some of these cavities may simulate a neurosensory retinal detachment or central serous chorioretinopathy on cursory clinical examination.5 To confirm that the features of the current patient1 are indeed related to the optic disc pit, it is necessary for the authors to provide an OCT scan which shows a connection of the presented cavity with the optic disc pit. Also, clear OCT scans of the fovea, both at presentation and at final follow-up would help our understanding of the visual recovery of the patient. The interval between the presenting (28 June 2012 OCT and final OCT (30 Nov 2012 is 5 months and not 6 months as described in the manuscript. For an effective comparison, both the presenting and final OCT scans should have been taken using either horizontal or vertical orientation over the macula. Though the spontaneous resolution of optic disc pit maculopathy is possible, visual recovery in usually unlikely and in such cases an alternate diagnosis needs to be excluded.

  10. Fragmentation Energy-Saving Theory of Full Face Rock Tunnel Boring Machine Disc Cutters

    Science.gov (United States)

    Zhang, Zhao-Huang; Gong, Guo-Fang; Gao, Qing-Feng; Sun, Fei

    2017-07-01

    Attempts to minimize energy consumption of a tunnel boring machine disc cutter during the process of fragmentation have largely focused on optimizing disc-cutter spacing, as determined by the minimum specific energy required for fragmentation; however, indentation tests showed that rock deforms plastically beneath the cutters. Equations for thrust were developed for both the traditional, popularly employed disc cutter and anew design based on three-dimensional theory. The respective energy consumption for penetration, rolling, and side-slip fragmentations were obtained. A change in disc-cutter fragmentation angles resulted in a change in the nature of the interaction between the cutter and rock, which lowered the specific energy of fragmentation. During actual field excavations to the same penetration length, the combined energy consumption for fragmentation using the newly designed cutters was 15% lower than that when using the traditional design. This paper presents a theory for energy saving in tunnel boring machines. Investigation results showed that the disc cutters designed using this theory were more durable than traditional designs, and effectively lowered the energy consumption.

  11. Comparison of optical coherence tomography and fundus photography for measuring the optic disc size.

    Science.gov (United States)

    Neubauer, Aljoscha S; Krieglstein, Tina R; Chryssafis, Christos; Thiel, Martin; Kampik, Anselm

    2006-01-01

    To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. Mean disc size was 1763 +/- 186 vertically and 1632 +/- 160 microm horizontally on planimetry. On OCT, values of 1772 +/- 317 microm vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 +/- 302 microm (p = 0.04) were obtained. The 95% limits of agreement were (-546 microm; +527 microm) for vertical and (-502 microm; +782 microm) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 microm for horizontal and 168 microm for vertical measurements. OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable.

  12. Quasi-periodic oscillations and the global modes of relativistic, MHD accretion discs

    Science.gov (United States)

    Dewberry, Janosz W.; Latter, Henrik N.; Ogilvie, Gordon I.

    2018-05-01

    The high-frequency quasi-periodic oscillations that punctuate the light curves of X-ray binary systems present a window on to the intrinsic properties of stellar-mass black holes and hence a testbed for general relativity. One explanation for these features is that relativistic distortion of the accretion disc's differential rotation creates a trapping region in which inertial waves (r-modes) might grow to observable amplitudes. Local analyses, however, predict that large-scale magnetic fields push this trapping region to the inner disc edge, where conditions may be unfavourable for r-mode growth. We revisit this problem from a pseudo-Newtonian but fully global perspective, deriving linearized equations describing a relativistic, magnetized accretion flow, and calculating normal modes with and without vertical density stratification. In an unstratified model we confirm that vertical magnetic fields drive r-modes towards the inner edge, though the effect depends on the choice of vertical wavenumber. In a global model we better quantify this susceptibility, and its dependence on the disc's vertical structure and thickness. Our calculations suggest that in thin discs, r-modes may remain independent of the inner disc edge for vertical magnetic fields with plasma betas as low as β ≈ 100-300. We posit that the appearance of r-modes in observations may be more determined by a competition between excitation and damping mechanisms near the ISCO than by the modification of the trapping region by magnetic fields.

  13. [Partial nucleotomy of the ovine disc as an in vivo model for disc degeneration].

    Science.gov (United States)

    Guder, E; Hill, S; Kandziora, F; Schnake, K J

    2009-01-01

    The aim of this study was to develop a suitable animal model for the clinical situation of progressive disc degeneration after microsurgical nucleotomy. Twenty sheep underwent standardised partial anterolateral nucleotomy at lumbar segment 3/4. After randomisation, 10 animals were sacrificed after 12 weeks (group 1). The remainder was sacrificed after 48 weeks (group 2). For radiological examination X-rays, MRI and post-mortem CT scans were performed. Lumbar discs L 3/4 with adjacent subchondral trabecular bone were harvested and analysed macroscopically and histologically. An image-analysing computer program was used to measure histomorphometric indices of bone structure. 17 segments could be evaluated. After 12 weeks (group 1) histological and radiological degenerative disc changes were noted. After 48 weeks (group 2), radiological signs in MRI reached statistical significance. Furthermore, group 2 showed significantly more osteophyte formations in CT scans. Histomorphometric changes of the disc and the adjacent vertebral bone structure suggest a significant progressive degenerative remodelling. The facet joints did not show any osteoarthrosis after 48 weeks. Partial nucleotomy of the ovine lumbar disc leads to radiological and histological signs of disc degeneration similar to those seen in humans after microsurgical nucleotomy. The presented in vivo model may be useful to evaluate new orthopaedic treatment strategies.

  14. A Kinome RNAi Screen in Drosophila Identifies Novel Genes Interacting with Lgl, aPKC, and Crb Cell Polarity Genes in Epithelial Tissues

    NARCIS (Netherlands)

    Parsons, Linda M.; Grzeschik, Nicola A; Amaratunga, Kasun; Burke, Peter; Quinn, Leonie M; Richardson, Helena E

    2017-01-01

    In both Drosophila melanogaster and mammalian systems, epithelial structure and underlying cell polarity are essential for proper tissue morphogenesis and organ growth. Cell polarity interfaces with multiple cellular processes that are regulated by the phosphorylation status of large protein

  15. The age-velocity dispersion relation of the Galactic discs from LAMOST-Gaia data

    Science.gov (United States)

    Yu, Jincheng; Liu, Chao

    2018-03-01

    We present the age-velocity dispersion relation (AVR) in three dimensions in the solar neighbourhood using 3564 commonly observed sub-giant/red giant branch stars selected from The Large Sky Area Multi-Object Fiber Spectroscopic Telescope, which gives the age and radial velocity, and Gaia, which measures the distance and proper motion. The stars are separated into metal-poor ([Fe/H] -0.2 dex) groups, so that the metal-rich stars are mostly α-poor, while the metal-poor group are mostly contributed by α-enhanced stars. Thus, the old and metal-poor stars likely belong to the chemically defined thick disc population, while the metal-rich sample is dominated by the thin disc. The AVR for the metal-poor sample shows an abrupt increase at ≳7 Gyr, which is contributed by the thick disc component. On the other hand, most of the thin disc stars with [Fe/H] > -0.2 dex display a power-law-like AVR with indices of about 0.3-0.4 and 0.5 for the in-plane and vertical dispersions, respectively. This is consistent with the scenario that the disc is gradually heated by the spiral arms and/or the giant molecular clouds. Moreover, the older thin disc stars (>7 Gyr) have a rounder velocity ellipsoid, i.e. σϕ/σz is close to 1.0, probably due to the more efficient heating in vertical direction. Particularly for the old metal-poor sample located with |z| > 270 pc, the vertical dispersion is even larger than its azimuthal counterpart. Finally, the vertex deviations and the tilt angles are plausibly around zero with large uncertainties.

  16. RNAi-Mediated Reverse Genetic Screen Identified Drosophila Chaperones Regulating Eye and Neuromuscular Junction Morphology

    Directory of Open Access Journals (Sweden)

    Sandeep Raut

    2017-07-01

    Full Text Available Accumulation of toxic proteins in neurons has been linked with the onset of neurodegenerative diseases, which in many cases are characterized by altered neuronal function and synapse loss. Molecular chaperones help protein folding and the resolubilization of unfolded proteins, thereby reducing the protein aggregation stress. While most of the chaperones are expressed in neurons, their functional relevance remains largely unknown. Here, using bioinformatics analysis, we identified 95 Drosophila chaperones and classified them into seven different classes. Ubiquitous actin5C-Gal4-mediated RNAi knockdown revealed that ∼50% of the chaperones are essential in Drosophila. Knocking down these genes in eyes revealed that ∼30% of the essential chaperones are crucial for eye development. Using neuron-specific knockdown, immunocytochemistry, and robust behavioral assays, we identified a new set of chaperones that play critical roles in the regulation of Drosophila NMJ structural organization. Together, our data present the first classification and comprehensive analysis of Drosophila chaperones. Our screen identified a new set of chaperones that regulate eye and NMJ morphogenesis. The outcome of the screen reported here provides a useful resource for further elucidating the role of individual chaperones in Drosophila eye morphogenesis and synaptic development.

  17. Two Algorithms for High-throughput and Multi-parametric Quantification of Drosophila Neuromuscular Junction Morphology.

    Science.gov (United States)

    Castells-Nobau, Anna; Nijhof, Bonnie; Eidhof, Ilse; Wolf, Louis; Scheffer-de Gooyert, Jolanda M; Monedero, Ignacio; Torroja, Laura; van der Laak, Jeroen A W M; Schenck, Annette

    2017-05-03

    Synaptic morphology is tightly related to synaptic efficacy, and in many cases morphological synapse defects ultimately lead to synaptic malfunction. The Drosophila larval neuromuscular junction (NMJ), a well-established model for glutamatergic synapses, has been extensively studied for decades. Identification of mutations causing NMJ morphological defects revealed a repertoire of genes that regulate synapse development and function. Many of these were identified in large-scale studies that focused on qualitative approaches to detect morphological abnormalities of the Drosophila NMJ. A drawback of qualitative analyses is that many subtle players contributing to NMJ morphology likely remain unnoticed. Whereas quantitative analyses are required to detect the subtler morphological differences, such analyses are not yet commonly performed because they are laborious. This protocol describes in detail two image analysis algorithms "Drosophila NMJ Morphometrics" and "Drosophila NMJ Bouton Morphometrics", available as Fiji-compatible macros, for quantitative, accurate and objective morphometric analysis of the Drosophila NMJ. This methodology is developed to analyze NMJ terminals immunolabeled with the commonly used markers Dlg-1 and Brp. Additionally, its wider application to other markers such as Hrp, Csp and Syt is presented in this protocol. The macros are able to assess nine morphological NMJ features: NMJ area, NMJ perimeter, number of boutons, NMJ length, NMJ longest branch length, number of islands, number of branches, number of branching points and number of active zones in the NMJ terminal.

  18. Comparative thoracic anatomy of the wild type and wingless (wg1cn1) mutant of Drosophila melanogaster (Diptera).

    Science.gov (United States)

    Fabian, Benjamin; Schneeberg, Katharina; Beutel, Rolf Georg

    2016-11-01

    Genetically modified organisms are crucial for our understanding of gene regulatory networks, physiological processes and ontogeny. With modern molecular genetic techniques allowing the rapid generation of different Drosophila melanogaster mutants, efficient in-depth morphological investigations become an important issue. Anatomical studies can elucidate the role of certain genes in developmental processes and point out which parts of gene regulatory networks are involved in evolutionary changes of morphological structures. The wingless mutation wg 1 of D. melanogaster was discovered more than 40 years ago. While early studies addressed the external phenotype of these mutants, the documentation of the internal organization was largely restricted to the prominent indirect flight muscles. We used SEM micrographs, histological serial sections, μ-computed tomography, CLSM and 3D reconstructions to study and document the thoracic skeletomuscular system of the wild type and mutant. A recently introduced nomenclature for the musculature of neopteran insects was applied to facilitate comparisons with closely or more distantly related taxa. The mutation is phenotypically mainly characterized by the absence of one or both wings and halteres. The wing is partly or entirely replaced by duplications of mesonotal structures, whereas the haltere and its associated muscles are completely absent on body sides showing the reduction. Both the direct and indirect mesothoracic flight muscles are affected by loss and reorientation of bundles or fibers. Our observations lead to the conclusion that the wingless mutation causes a homeotic transformation in the imaginal discs of wings and halteres with a direct effect on the development of skeletal structures and an indirect effect on the associated muscular system. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Adaptive genic evolution in the Drosophila genomes

    DEFF Research Database (Denmark)

    Shapiro, Joshua A; Huang, Wei; Zhang, Chenhui

    2007-01-01

    and stable population. In this study, we sequenced 419 genes from 24 lines of Drosophila melanogaster and its close relatives. Together with data from Drosophila simulans, these data reveal the following. (i) Approximately 10% of the loci in regions of normal recombination are much less polymorphic at silent...... sites than expected, hinting at the action of selective sweeps. (ii) The level of polymorphism is negatively correlated with the rate of nonsynonymous divergence across loci. Thus, even under strict neutrality, the ratio of amino acid to silent nucleotide changes (A:S) between Drosophila species...

  20. Polycomb-dependent regulatory contacts between distant Hox loci in Drosophila

    DEFF Research Database (Denmark)

    Bantignies, Frédéric; Roure, Virginie; Comet, Itys

    2011-01-01

    In Drosophila melanogaster, Hox genes are organized in an anterior and a posterior cluster, called Antennapedia complex and bithorax complex, located on the same chromosome arm and separated by 10 Mb of DNA. Both clusters are repressed by Polycomb group (PcG) proteins. Here, we show that genes...... of the two Hox complexes can interact within nuclear PcG bodies in tissues where they are corepressed. This colocalization increases during development and depends on PcG proteins. Hox gene contacts are conserved in the distantly related Drosophila virilis species and they are part of a large gene...

  1. The diagnosis of internal disc disruption with CT discography

    International Nuclear Information System (INIS)

    Liu Miao; Chen Xingcan; Li Xiaohong; Pan Yongqin

    2008-01-01

    Objective: To study the value of diagnosis for internal disc disruption (IDD)with CT discography(CTD). Methods: 42 discs of 32 patients showing no disc herniation on CT or MRI, but suffering from chronic low back pain, were undertaken CTD to work out the types of CTD with correlation between contrast medium dosages and the induction of pain. Results: CTD demonstrated 4 types of IDD which was individually correlated with the contrast dosages and induced pain; furthermore the dosages for positive and negative disc cases showed significant differece (P<0.01). Conclusions: CTD can show the direct sign of internal disc disruption, providing more information than conventional discography. (authors)

  2. What use is an infertile sperm? A comparative study of sperm-heteromorphic Drosophila

    DEFF Research Database (Denmark)

    Holman, Luke; Freckleton, Robert P; Snook, Rhonda R

    2007-01-01

    Sperm size and number are important determinants of male reproductive success. The genus Drosophila exhibits a remarkable diversity of sperm production strategies, including the production of multiple sperm morphs by individual males, a phenomenon called sperm heteromorphism. Sperm-heteromorphic ......Sperm size and number are important determinants of male reproductive success. The genus Drosophila exhibits a remarkable diversity of sperm production strategies, including the production of multiple sperm morphs by individual males, a phenomenon called sperm heteromorphism. Sperm......-heteromorphic Drosophila species in the obscura group produce large numbers of infertile "parasperm" in addition to fertile eusperm. Parasperm have been hypothesized to perform a number of roles in place of fertilization, predominantly focused on their potential function in postcopulatory sexual selection. However...

  3. Queixas auditivas de disc jockeys da cidade de Recife Auditory complaints in disc jockeys in Recife

    Directory of Open Access Journals (Sweden)

    Eliza Maia de Britto Macedo

    2011-06-01

    Full Text Available OBJETIVO: investigar a ocorrência de queixas auditivas em disc jockeys da cidade de Recife/PE. MÉTODOS: foi realizada uma entrevista com 30 disc jockeys, com idade entre 19 e 28 anos, abordando informações ocupacionais, conhecimentos gerais sobre o ruído e queixas auditivas (diminuição da acuidade auditiva, desconforto a sons intensos, zumbido, sensação de ouvido abafado e otalgia. A análise foi realizada por meio de abordagem quantitativa, utilizando o teste estatístico t-student. RESULTADOS: dentre os dados mais relevantes, destacam-se: 46,7% dos disc jockeys apresentaram, espontaneamente, queixas auditivas, em especial, a diminuição da acuidade auditiva (relatada por todos os sujeitos; 14 disc jockeys (46,67% referiram desconforto a sons intensos e 13 (43,33% mencionaram zumbido. Todos afirmaram ter conhecimento sobre os riscos do ruído para a saúde auditiva, mas 76,7% não realizam qualquer medida preventiva de suas consequências. A perda auditiva foi referida pelos sujeitos como o principal risco da exposição a níveis intensos de pressão sonora. CONCLUSÃO: todos os disc jockeys apresentaram queixa de perda auditiva e, entre as demais queixas auditivas, destacaram-se o desconforto a sons intensos e o zumbido. Tendo em vista a irreversibilidade da perda auditiva induzida por elevados níveis de pressão sonora, os disc jockeys devem ser periodicamente avaliados a fim de que se confirme ou não a perda auditiva de que se queixaram e, caso ela exista, deve ser monitorada para que seja passível de intervenção pelo fonoaudiólogo. Desta forma, percebe-se a necessidade de atuação da Fonoaudiologia junto aos disc jockeys, uma vez que poder-se-á propiciar a otimização do exercício profissional com o mínimo de risco possível.PURPOSE: to investigate the occurrence of auditory complaints in disc jockeys from the city of Recife/PE. METHODS: an interview was carried through with 30 disc jockeys aged between 19 and 48 years

  4. Synchronized Bilateral Synaptic Inputs to Drosophila melanogaster Neuropeptidergic Rest/Arousal Neurons

    DEFF Research Database (Denmark)

    McCarthy, E. V.; Wu, Y.; deCarvalho, T.

    2011-01-01

    Neuropeptide PDF (pigment-dispersing factor)-secreting large ventrolateral neurons (lLN(v)s) in the Drosophila brain regulate daily patterns of rest and arousal. These bilateral wake-promoting neurons are light responsive and integrate information from the circadian system, sleep circuits...

  5. The Impact of Odor--Reward Memory on Chemotaxis in Larval "Drosophila"

    Science.gov (United States)

    Schleyer, Michael; Reid, Samuel F.; Pamir, Evren; Saumweber, Timo; Paisios, Emmanouil; Davies, Alexander; Gerber, Bertram; Louis, Matthieu

    2015-01-01

    How do animals adaptively integrate innate with learned behavioral tendencies? We tackle this question using chemotaxis as a paradigm. Chemotaxis in the "Drosophila" larva largely results from a sequence of runs and oriented turns. Thus, the larvae minimally need to determine (i) how fast to run, (ii) when to initiate a turn, and (iii)…

  6. Neurofibromatosis-like phenotype in Drosophila caused by lack of glucosylceramide extension

    DEFF Research Database (Denmark)

    Dahlgaard, Katja; Jung, Anita; Qvortrup, Klaus

    2012-01-01

    Glycosphingolipids (GSLs) are of fundamental importance in the nervous system. However, the molecular details associated with GSL function are largely unknown, in part because of the complexity of GSL biosynthesis in vertebrates. In Drosophila, only one major GSL biosynthetic pathway exists...

  7. Spaceflight-related suboptimal conditions can accentuate the altered gravity response of Drosophila transcriptome

    NARCIS (Netherlands)

    Herranz, R.; Benguría, A.; Laván, D.A.; López-Vidriero, I.; Gasset, G.; Javier Medina, F.; van Loon, J.J.W.A.; Marco, R.

    2010-01-01

    Genome-wide transcriptional profiling shows that reducing gravity levels during Drosophila metamorphosis in the International Space Station (ISS) causes important alterations in gene expression: a large set of differentially expressed genes (DEGs) are observed compared to 1g controls. However, the

  8. Mapping the pericentric heterochromatin by comparative genomic hybridization analysis and chromosome deletions in Drosophila melanogaster

    OpenAIRE

    He, Bing; Caudy, Amy; Parsons, Lance; Rosebrock, Adam; Pane, Attilio; Raj, Sandeep; Wieschaus, Eric

    2012-01-01

    Heterochromatin represents a significant portion of eukaryotic genomes and has essential structural and regulatory functions. Its molecular organization is largely unknown due to difficulties in sequencing through and assembling repetitive sequences enriched in the heterochromatin. Here we developed a novel strategy using chromosomal rearrangements and embryonic phenotypes to position unmapped Drosophila melanogaster heterochromatic sequence to specific chromosomal regions. By excluding seque...

  9. Somatic mutation and recombination induced by fast neutrons in the wing spot test of Drosophila Melanogaster

    International Nuclear Information System (INIS)

    Guzman R, J.; Varela, A.; Policroniades, R.; Delfin, A.; Graf, U.

    1994-01-01

    In the last decades, a large number of studies have been undertaken to evaluate the biological effects of gamma and X rays in Drosophila melanogaster. The majority of these investigations were performed on female and male germ cells. However, comparatively little is known in relation to the biological effects of fast neutrons, and especially in relation to their effects in somatic cells. (Author)

  10. The role of reduced oxygen in the developmental physiology of growth and metamorphosis initiation in Drosophila

    Science.gov (United States)

    Rearing oxygen level is known to affect final body size in a variety of insects, but the physiological mechanisms by which oxygen affects size are incompletely understood. In Manduca and Drosophila, the larval size at which metamorphosis is initiated largely determines adult size, and metamorphosis ...

  11. Fas ligand exists on intervertebral disc cells: a potential molecular mechanism for immune privilege of the disc.

    Science.gov (United States)

    Takada, Toru; Nishida, Kotaro; Doita, Minoru; Kurosaka, Masahiro

    2002-07-15

    Rat and human intervertebral disc specimens were examined immunohistochemically. Reverse transcription polymerase chain reaction (RT-PCR) analysis was also performed on rat disc tissue to demonstrate the existence of Fas ligand. To clarify the existence of Fas ligand on intact intervertebral disc cells. The nucleus pulposus has been reported to be an immune-privileged site. The immune-privileged characteristic in other tissues such as the retina and testis has been attributed to the local expression of Fas ligand, which acts by inducing apoptosis of invading Fas-positive T-cells. The existence of Fas ligand in normal disc cells has not yet been addressed. Skeletally mature SD male rats were killed, and the coccygeal discs were harvested. Human disc specimens were obtained from idiopathic scoliosis patients during surgical procedures. Immunohistochemical staining for Fas ligand was performed for cross-sections of the discs by standard procedures. Reverse transcription polymerase chain reaction analysis was also carried out to demonstrate Fas ligand mRNA expression on rat intervertebral discs. Testes of the rats were used for positive controls, and muscles were used for negative controls. The sections were observed by light microscopy. The nucleus pulposus cells exhibited intense positive immune staining for Fas ligand. The outer anulus fibrosus cells and notochordal cells exhibited little immunopositivity. The positive controls exhibited positive immune staining, and the negative control showed no immunopositivity. The result of RT-PCR confirmed the existence of Fas ligand in disc cells. The human nucleus pulposus cells showed a similar predilection to rat disc cells. We demonstrated the existence of Fas ligand on disc cells, which should play a key role in the potential molecular mechanism to maintain immune privilege of the disc. Immune privilege and Fas ligand expression of the intervertebral disc may provide a new insight for basic science research as well as

  12. MR image assessment of disc configuration and degree of anterior disc displacement in internal derangement related to age

    International Nuclear Information System (INIS)

    Igarashi, Chinami; Kobayashi, Kaoru; Imanaka, Masahiro; Yuasa, Masao; Yamamoto, Akira

    1999-01-01

    This study was designed to evaluate the configuration of the articular disc and degree of anterior disc displacement on magnetic resonance (MR) imagings in temporomandibular joints (TMJs) with internal derangement. A total of 363 joints diagnosed as having anterior disc displacement with reduction (ADD w R) and 523 joints diagnosed as having anterior disc displacement without reduction (ADD wo R) by MR imaging were examined. These joints did not show severe osseous changes on the condylar head or glenoid fossa. We assessed the configuration of the articular disc and degree of anterior disc displacement. In the ADD w R group, 82.6% of the articular discs showed biconcave configuration; enlargement of the posterior band in 4.6%, biconvex configuration in 0.5%, and others in 10.7%. Moreover 62.5% of the discs showed a slight degree of anterior disc displacement; were 27.2% moderately displaced and were 10.2% severe displaced. The prevalence of slightly displaced discs was higher in the TMJs of cases over 50 years of age than in cases under 30 years in the ADD w R group. On the other hand, in the ADD wo R group 35.9% of the articular discs showed biconcave configuration; enlargement of the posterior band in 12.6%, biconvex configuration in 25.4%, and others in 22.3%. Furthermore, 4.4% of the discs were slightly displaced; 43.9% moderately displaced and 51.6% were severely displaced. The prevalence of severely displaced and deformed discs in joints of cases over 40 years of age was high in the ADD wo R group. The prevalence of slightly displaced biconcave discs was higher in the ADD w R group. The other hand, the prevalence of severely displaced deformed discs was higher in the ADD wo R group. MR findings of internal derangement of the TMJ were found to be significantly correlated with age. (author)

  13. Studies on Drosophila radiosensitivity strains

    International Nuclear Information System (INIS)

    Varentsova, E.R.; Sharygin, V.I.; Khromykh, Yu.U.

    1985-01-01

    Fertility of radiosensitive mutant drosophila female strain rad (2) 201 61 after irradiation and frequency of dominant lethal mutations (DLM), induced by γ-radiation for 0-5 h and 5-7 days, are investigated. It is shown, that oocytes of the mutant strain are more radiosensitive as compared with cells of mongrel flies as to criterion of DLM appearance over the period of maturing. Early oocytes of stages 2-7 are the most sensitive, i.e. at the stages, corresponding to the manifestation of previously established recombination-defective properties of mutations rad (2) 201 61 . It is also sown, that doses of γ-rays, exceeding 10 Gy produce a strong sterilizing effect on mutant females due to destruction and resorption of egg chambers, irradiated at the stages of previtellogenetic growth of oocytes. In females, carrying mutation of radiosensitivity there is no direct correlation betwen sensitivity of oocytes proper to DLM induction and sensitivity of egg folleicles to resorbing effect of γ-rays. The ways of possible involvement of mutant locus studied into genetic processes in various specialized cells of drosophila

  14. Examination of turbine discs from nuclear power plants

    International Nuclear Information System (INIS)

    Czajkowski, C.J.; Weeks, J.R.

    1982-01-01

    Investigations were performed on a cracked turbine disc from the Cooper Nuclear Power Station, and on two failed turbine discs (governor and generator ends) from the Yankee-Rowe Nuclear Power Station. Cooper is a boiling water reactor (BWR) which went into commercial operation in July 1974, and Yankee-Rowe is a pressurized water reactor (PWR) which went into commercial operation in June 1961. Cracks were identified in the bore of the Cooper disc after 41,913 hours of operation, and the disc removed for repair. At Yankee-Rowe two discs failed after 100,000 hours of operation. Samples of the Cooper disc and both Yankee-Rowe disc (one from the governor and one from the generator end of the LP turbine) were sent to Brookhaven National Laboratory (BNL) for failure analysis

  15. Maggot Instructor: Semi-Automated Analysis of Learning and Memory in Drosophila Larvae

    Directory of Open Access Journals (Sweden)

    Urte Tomasiunaite

    2018-06-01

    Full Text Available For several decades, Drosophila has been widely used as a suitable model organism to study the fundamental processes of associative olfactory learning and memory. More recently, this condition also became true for the Drosophila larva, which has become a focus for learning and memory studies based on a number of technical advances in the field of anatomical, molecular, and neuronal analyses. The ongoing efforts should be mentioned to reconstruct the complete connectome of the larval brain featuring a total of about 10,000 neurons and the development of neurogenic tools that allow individual manipulation of each neuron. By contrast, standardized behavioral assays that are commonly used to analyze learning and memory in Drosophila larvae exhibit no such technical development. Most commonly, a simple assay with Petri dishes and odor containers is used; in this method, the animals must be manually transferred in several steps. The behavioral approach is therefore labor-intensive and limits the capacity to conduct large-scale genetic screenings in small laboratories. To circumvent these limitations, we introduce a training device called the Maggot Instructor. This device allows automatic training up to 10 groups of larvae in parallel. To achieve such goal, we used fully automated, computer-controlled optogenetic activation of single olfactory neurons in combination with the application of electric shocks. We showed that Drosophila larvae trained with the Maggot Instructor establish an odor-specific memory, which is independent of handling and non-associative effects. The Maggot Instructor will allow to investigate the large collections of genetically modified larvae in a short period and with minimal human resources. Therefore, the Maggot Instructor should be able to help extensive behavioral experiments in Drosophila larvae to keep up with the current technical advancements. In the longer term, this condition will lead to a better understanding of

  16. Are Collapsed Cervical Discs Amenable to Total Disc Arthroplasty?: Analysis of Prospective Clinical Data With 2-Year Follow Up.

    Science.gov (United States)

    Patwardhan, Avinash G; Carandang, Gerard; Voronov, Leonard I; Havey, Robert M; Paul, Gary A; Lauryssen, Carl; Coric, Domagoj; Dimmig, Thomas; Musante, David

    2016-12-15

    Analysis of prospectively collected radiographic data. To investigate the influence of preoperative index-level range of motion (ROM) and disc height on postoperative ROM after cervical total disc arthroplasty (TDA) using compressible disc prostheses. Clinical studies demonstrate benefits of motion preservation over fusion; however, questions remain unanswered as to which preoperative factors have the ability to identify patients who are most likely to have good postoperative motion, which is the primary rationale for TDA. We analyzed prospectively collected data from a single-arm, multicenter study with 2-year follow up of 30 patients with 48 implanted levels. All received compressible cervical disc prostheses of 6 mm-height (M6C, Spinal Kinetics, Sunnyvale, CA). The influence of index-level preoperative disc height and ROM (each with two levels: below-median and above-median) on postoperative ROM was analyzed using 2 x 2 ANOVA. We further analyzed the radiographic outcomes of a subset of discs with preoperative height less than 3 mm, the so-called "collapsed" discs. Shorter (3.0 ± 0.4 mm) discs were significantly less mobile preoperatively than taller (4.4 ± 0.5 mm) discs (6.7° vs. 10.5°, P = 0.01). The postoperative ROM did not differ between the shorter and taller discs (5.6° vs. 5.0°, P = 0.63). Tall discs that were less mobile preoperatively had significantly smaller postoperative ROM than short discs with above-median preoperative mobility (P < 0.05). The "collapsed discs" (n = 8) were less mobile preoperatively compared with all discs combined (5.1° vs. 8.6°, P < 0.01). These discs were distracted to more than two times the preoperative height, from 2.6 to 5.7 mm, and had significantly greater postoperative ROM than all discs combined (7.6° vs. 5.3°, P < 0.05). We observed a significant interaction between preoperative index-level disc height and ROM in influencing postoperative ROM. Although limited by small sample

  17. Evaluation of bone and disc configuration in TMJ internal derangement

    International Nuclear Information System (INIS)

    Park, Cheol Woo; Hwang, Eui Hwan; Lee, Sang Rae

    2001-01-01

    To investigate bone and disc configuration on MR images in internal derangement related to age. MR images of 150 TMJs in 107 patients were analyzed to determine the morphologic changes. Two groups were distinguished to be correlated with age. Group 1 consisted of TMJs that were diagnosed as having anterior disc displacement with reduction (ADDwR), and Group 2 consisted of TMJs that were diagnosed as having anterior disc displacement without reduction (ADDwR). We assessed the configuration of the articular disc, degree of anterior disc displacement, and osseous changes of TMJs. The third decade (83 of 150 joints) was most frequent in this study. In the ADDwR group biconcave disc was most frequent at all ages except fifth decade, but in the ADDwoR group deformed discs was most frequent at third and forth decades. In the ADDwR group slightly displaced discs was most frequent at all ages, but in the ADDwoR group severely displaced discs was most frequent at second decade, and the degree of disc displacement was increased with aging over 30 years of age. TM joints showed osseous changes in 17% of the ADDwR group, and in 30% of the ADDwoR group. MR findings of osseous changes of the TMJ were not found to be significantly correlated with age. The prevalence of deformation of disc, displacement of disc, and osseous changes of TMJ was higher in the ADDwoR group than in the ADDwR group. MR findings of disc configuration and degree of disc displacement were found to be correlated with age

  18. Cervical disc arthroplasty: Pros and cons.

    Science.gov (United States)

    Moatz, Bradley; Tortolani, P Justin

    2012-01-01

    Cervical disc arthroplasty has emerged as a promising potential alternative to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. Despite a history of excellent outcomes after ACDF, the question as to whether a fusion leads to adjacent segment degeneration remains unanswered. Numerous US investigational device exemption trials comparing cervical arthroplasty to fusion have been conducted to answer this question. This study reviews the current research regarding cervical athroplasty, and emphasizes both the pros and cons of arthroplasty as compared with ACDF. Early clinical outcomes show that cervical arthroplasty is as effective as the standard ACDF. However, this new technology is also associated with an expanding list of novel complications. Although there is no definitive evidence that cervical disc replacement reduces the incidence of adjacent segment degeneration, it does show other advantages; for example, faster return to work, and reduced need for postoperative bracing.

  19. MR imaging of degenerative disc disease

    International Nuclear Information System (INIS)

    Farshad-Amacker, Nadja A.; Farshad, Mazda; Winklehner, Anna; Andreisek, Gustav

    2015-01-01

    Highlights: • This systematic literature review summarizes the current knowledge on MR imaging in degenerative disc disease. • Different classification systems for segmental spine degeneration are summarized. • It outlines the diagnostic limitations of MR imaging. - Abstract: Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided

  20. MR imaging of degenerative disc disease

    Energy Technology Data Exchange (ETDEWEB)

    Farshad-Amacker, Nadja A., E-mail: nadja.farshad@usz.ch [Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, Zurich (Switzerland); Farshad, Mazda [Department of Orthopaedic Surgery, Balgrist University Hospital, Zurich (Switzerland); Winklehner, Anna; Andreisek, Gustav [Institute of Diagnostic and Interventional Radiology, University Hospital of Zurich, Zurich (Switzerland)

    2015-09-15

    Highlights: • This systematic literature review summarizes the current knowledge on MR imaging in degenerative disc disease. • Different classification systems for segmental spine degeneration are summarized. • It outlines the diagnostic limitations of MR imaging. - Abstract: Magnet resonance imaging (MRI) is the most commonly used imaging modality for diagnosis of degenerative disc disease (DDD). Lack of precise observations and documentation of aspects within the complex entity of DDD might partially be the cause of poor correlation of radiographic findings to clinical symptoms. This literature review summarizes the current knowledge on MRI in DDD and outlines the diagnostic limitations. The review further sensitizes the reader toward awareness of potentially untended aspects of DDD and the interaction of DDD and endplate changes. A summary of the available classifications for DDD is provided.

  1. Material Science in Cervical Total Disc Replacement

    Science.gov (United States)

    Pham, Martin H.; Mehta, Vivek A.; Tuchman, Alexander; Hsieh, Patrick C.

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation. PMID:26523281

  2. Material Science in Cervical Total Disc Replacement

    Directory of Open Access Journals (Sweden)

    Martin H. Pham

    2015-01-01

    Full Text Available Current cervical total disc replacement (TDR designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti, and cobalt-chrome (CoCr. These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

  3. Material Science in Cervical Total Disc Replacement.

    Science.gov (United States)

    Pham, Martin H; Mehta, Vivek A; Tuchman, Alexander; Hsieh, Patrick C

    2015-01-01

    Current cervical total disc replacement (TDR) designs incorporate a variety of different biomaterials including polyethylene, stainless steel, titanium (Ti), and cobalt-chrome (CoCr). These materials are most important in their utilization as bearing surfaces which allow for articular motion at the disc space. Long-term biological effects of implanted materials include wear debris, host inflammatory immune reactions, and osteolysis resulting in implant failure. We review here the most common materials used in cervical TDR prosthetic devices, examine their bearing surfaces, describe the construction of the seven current cervical TDR devices that are approved for use in the United States, and discuss known adverse biological effects associated with long-term implantation of these materials. It is important to appreciate and understand the variety of biomaterials available in the design and construction of these prosthetics and the considerations which guide their implementation.

  4. The Astral Curved Disc of Chevroches (France)

    Science.gov (United States)

    Devevey, F. Rousseau, A.

    2009-08-01

    The excavation of the unexplored secondary agglomeration in Chevroches (Nièvre), from 2001 to 2002, directed by F. Devevey (INRAP), has led to the discovery of an astrological bronze curved disc of a type unknown in the ancient world; it is inscribed with three lines in Greek transcribing Egyptian an Roman months, and the twelve signs of the zodiac. This article presents the first observations.

  5. Influence of degenerative changes of intervertebral disc

    Directory of Open Access Journals (Sweden)

    WANG Yi

    2012-04-01

    Full Text Available 【Abstract】Objective: To investigate the material properties of normal and degenerated intervertebral discs (IVDs and examine the effect of degenerative changes on IVD pathology. Methods: A computer-based online search was under-taken to identify English articles about material properties of IVDs published from January 1950 to 2011 in PubMed database. The retrieved keywords included material properties, intervertebral disc and degeneration. Based on the principles of reliability, advancement and efficiency, the obtained data were primarily examined, and the original source was retrieved to read the full-text. Repetitive articles were excluded. The data of material properties of normal and degenerated IVDs were summarized and analyzed by meta-analysis. Results: The data of Young's modulus, Poisson's ratio, shear modulus, hydraulic permeability and intradiscal pres-sure of normal and degenerated IVDs were obtained. Com-pared with normal IVDs, the Young's modulus and shear modulus of annulus fibrosus and nucleus pulposus were higher in degenerated IVDs, the Poisson's ratio was lower while the hydraulic permeability and intradiscal pressure were higher. Besides, the degeneration-related alterations in IVDs had an influence both on itself and other spinal structures, leading to diseases such as bulging disc, discogenic pain and spinal stenosis. Meanwhile, the heavy mechanical loading and injury indicated important pathways to IVD degeneration. Conclusions: To a certain extent, the degenerative changes of IVD influence its material properties. And the degeneration-related alterations of composition can cause structural failure of IVDs, leading to injuries and diseases. Key words: Intervertebral disc; Mechanical phenomena; Degeneration; Elastic modulus; Permeability; Pathology

  6. The Drosophila DOCK family protein Sponge is required for development of the air sac primordium

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Kazushge; Anh Suong, Dang Ngoc; Yoshida, Hideki; Yamaguchi, Masamitsu, E-mail: myamaguc@kit.ac.jp

    2017-05-15

    Dedicator of cytokinesis (DOCK) family genes are known as DOCK1-DOCK11 in mammals. DOCK family proteins mainly regulate actin filament polymerization and/or depolymerization and are GEF proteins, which contribute to cellular signaling events by activating small G proteins. Sponge (Spg) is a Drosophila counterpart to mammalian DOCK3/DOCK4, and plays a role in embryonic central nervous system development, R7 photoreceptor cell differentiation, and adult thorax development. In order to conduct further functional analyses on Spg in vivo, we examined its localization in third instar larval wing imaginal discs. Immunostaining with purified anti-Spg IgG revealed that Spg mainly localized in the air sac primordium (ASP) in wing imaginal discs. Spg is therefore predicted to play an important role in the ASP. The specific knockdown of Spg by the breathless-GAL4 driver in tracheal cells induced lethality accompanied with a defect in ASP development and the induction of apoptosis. The monitoring of ERK signaling activity in wing imaginal discs by immunostaining with anti-diphospho-ERK IgG revealed reductions in the ERK signal cascade in Spg knockdown clones. Furthermore, the overexpression of D-raf suppressed defects in survival and the proliferation of cells in the ASP induced by the knockdown of Spg. Collectively, these results indicate that Spg plays a critical role in ASP development and tracheal cell viability that is mediated by the ERK signaling pathway. - Highlights: • Spg mainly localizes in the air sac primordium in wing imaginal discs. • Spg plays a critical role in air sac primordium development. • Spg positively regulates the ERK signal cascade.

  7. Functional Analysis of Drosophila NF1

    National Research Council Canada - National Science Library

    Bernards, Andre

    2005-01-01

    ...) for Ras, yet homozygous loss of a highly conserved Drosophila NF1 ortholog results in several phenotypes that are insensitive to manipulating Ras signal transduction, but rescued by increasing...

  8. The Drosophila bipectinata species complex: phylogenetic ...

    Indian Academy of Sciences (India)

    PARUL BANERJEE

    c Indian Academy of Sciences. RESEARCH ARTICLE. The Drosophila bipectinata species complex: phylogenetic relationship among different members based on chromosomal variations. PARUL BANERJEE and BASHISTH N. SINGH. ∗. Genetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi ...

  9. Drosophila melanogaster gene expression changes after spaceflight.

    Data.gov (United States)

    National Aeronautics and Space Administration — Gene expression levels were determined in 3rd instar and adult Drosophila melanogaster reared during spaceflight to elucidate the genetic and molecular mechanisms...

  10. Ecdysteroid receptors in Drosophila melanogaster adult females

    Science.gov (United States)

    Ecdysteroid receptors were identified and partially characterized from total cell extracts of whole animals and dissected tissues from Drosophila melanogaster adult females. Binding studies indicated the presence of two ecdysteroid binding components having high affinity and specificity consistent w...

  11. Optic disc and peripapillary retinal nerve fiber layer characteristics associated with glaucomatous optic disc in young myopia.

    Science.gov (United States)

    Lee, Jong Eun; Sung, Kyung Rim; Park, Ji Min; Yoon, Joo Young; Kang, Sung Yong; Park, Sung Bae; Koo, Hyung Jin

    2017-03-01

    To explore optic disc and peripapillary retinal nerve fiber layer (RNFL) features associated with glaucomatous optic disc (GOD) in young myopia. Presence of GOD, optic disc tilt, and disc torsion were determined using fundus photographs. If the measured disc tilt ratio was >1.3, the optic disc was classified as tilted. Optic disc torsion was defined as a >15° deviation in the long axis of the optic disc from the vertical meridian. The average and four quadrants RNFL thicknesses were assessed using spectral domain optical coherence tomography (SD-OCT). Logistic regression analyses were performed to identify factors associated with the presence of GOD. Nine hundred and sixty myopic subjects were recruited from four refractive surgery clinic databases. The mean age was 26.6 ± 5.7 years and spherical equivalent (SE) was -5.5 ± 2.5 diopters. Among 960 eyes, 26 (2.7%) received GOD group classification. Among 934 normal eyes, 290 (31.0%) had titled optic discs. Eighteen eyes (69.2%) in the GOD group had tilted optic discs. When compared to normal eyes, the GOD group had significantly higher tilt ratios (1.4 ± 0.2 vs. 1.2 ± 0.1, p Optic disc tilt was found in approximately one-third of young myopic eyes and was independently associated with the presence of GOD.

  12. Abolishment of Spontaneous Flight Turns in Visually Responsive Drosophila.

    Science.gov (United States)

    Ferris, Bennett Drew; Green, Jonathan; Maimon, Gaby

    2018-01-22

    Animals react rapidly to external stimuli, such as an approaching predator, but in other circumstances, they seem to act spontaneously, without any obvious external trigger. How do the neural processes mediating the execution of reflexive and spontaneous actions differ? We studied this question in tethered, flying Drosophila. We found that silencing a large but genetically defined set of non-motor neurons virtually eliminates spontaneous flight turns while preserving the tethered flies' ability to perform two types of visually evoked turns, demonstrating that, at least in flies, these two modes of action are almost completely dissociable. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Dynamic analysis of three autoventilated disc brakes

    Directory of Open Access Journals (Sweden)

    Ricardo A. García-León

    2017-09-01

    Full Text Available The braking system of a car must meet several requirements, among which safety is the most important. It is also composed of a set of mechanical parts such as springs, different types of materials (Metallic and Non Metallic, gases and liquids. The brakes must work safely and predictably in all circumstances, which means having a stable level of friction, in any condition of temperature, humidity and salinity of the environment. For a correct design and operation of brake discs, it is necessary to consider different aspects, such as geometry, type of material, mechanical strength, maximum temperature, thermal deformation, cracking resistance, among others. Therefore, the main objective of this work is to analyze the dynamics and kinetics of the brake system from the pedal as the beginning of mathematical calculations to simulate the behavior and Analysis of Finite Elements (FEA, with the help of SolidWorks Simulation Software. The results show that the third brake disc works best in relation to the other two discs in their different working conditions such as speed and displacement in braking, concluding that depending on the geometry of the brake and the cooling channels these systems can be optimized that are of great importance for the automotive industry.

  14. Percutaneous treatment of intervertebral disc herniation.

    Science.gov (United States)

    Buy, Xavier; Gangi, Afshin

    2010-06-01

    Interventional radiology plays a major role in the management of symptomatic intervertebral disc herniations. In the absence of significant pain relief with conservative treatment including oral pain killers and anti-inflammatory drugs, selective image-guided periradicular infiltrations are generally indicated. The precise control of needle positioning allows optimal distribution of steroids along the painful nerve root. After 6 weeks of failure of conservative treatment including periradicular infiltration, treatment aiming to decompress or remove the herniation is considered. Conventional open surgery offers suboptimal results and is associated with significant morbidity. To achieve minimally invasive discal decompression, different percutaneous techniques have been developed. Their principle is to remove a small volume of nucleus, which results in an important reduction of intradiscal pressure and subsequently reduction of pressure inside the disc herniation. However, only contained disc herniations determined by computed tomography or magnetic resonance are indicated for these techniques. Thermal techniques such as radiofrequency or laser nucleotomy seem to be more effective than purely mechanical nucleotomy; indeed, they achieve discal decompression but also thermal destruction of intradiscal nociceptors, which may play a major role in the physiopathology of discal pain. The techniques of image-guided spinal periradicular infiltration and percutaneous nucleotomy with laser and radiofrequency are presented with emphasis on their best indications.

  15. Can Exercise Positively Influence the Intervertebral Disc?

    Science.gov (United States)

    Belavý, Daniel L; Albracht, Kirsten; Bruggemann, Gert-Peter; Vergroesen, Pieter-Paul A; van Dieën, Jaap H

    2016-04-01

    To better understand what kinds of sports and exercise could be beneficial for the intervertebral disc (IVD), we performed a review to synthesise the literature on IVD adaptation with loading and exercise. The state of the literature did not permit a systematic review; therefore, we performed a narrative review. The majority of the available data come from cell or whole-disc loading models and animal exercise models. However, some studies have examined the impact of specific sports on IVD degeneration in humans and acute exercise on disc size. Based on the data available in the literature, loading types that are likely beneficial to the IVD are dynamic, axial, at slow to moderate movement speeds, and of a magnitude experienced in walking and jogging. Static loading, torsional loading, flexion with compression, rapid loading, high-impact loading and explosive tasks are likely detrimental for the IVD. Reduced physical activity and disuse appear to be detrimental for the IVD. We also consider the impact of genetics and the likelihood of a 'critical period' for the effect of exercise in IVD development. The current review summarises the literature to increase awareness amongst exercise, rehabilitation and ergonomic professionals regarding IVD health and provides recommendations on future directions in research.

  16. [Surgical treatment of thoracic disc herniation].

    Science.gov (United States)

    Hrabálek, L; Kalita, O; Langová, K

    2010-08-01

    The aim of this study was to compare the efficiency of different surgical approaches to thoracic disc herniation, and to show the role of segmental fusion and selection of an appropriate microsurgical decompression technique for the successful outcome of surgery. A group of 27 patients, 10 men and 17 women, between 31 and 70 years (average age, 49.33 years) were included in this prospective study. They underwent surgery for thoracic degeneration disc disease in the period from June 1994 to August 2008. In all patients, the severity of myelopathy was assessed using the grading Frankel system and JOA score, axial and radicular pain intensity was evaluated with VAS and ODI rating systems. The diagnosis was established on the basis of thoracic spine radiography, thoracic spine MRI and a CT scan of the segment. A total of 30 thoracic segments, in the range of Th4/Th5 to Th12/L1, were indicated for surgery. Localisation of the hernia was medial at 19 segments, mediolateral at three and lateral at eight segments. Soft disc herniation was found in 17 cases and hard disc protrusion at the remaining 13 segments. Surgery for significant myelopathy was carried out in 23 patients and for pain in four patients. According to the surgical procedure used, the patients were allocated to two groups: group A comprised 10 patients treated without disc replacement through a laminectomy or a costotransversectomy exposure, and group B consisted of 17 patients undergo- ing intersomatic fusion via a thoracotomy. Clinical and radiographic examinations were made at regular intervals for at least 1 year of follow-up. The results of clinical assessment, including JOA scores, JOA Recovery Rate, VAS scores at rest and after exercise and ODI, were statistically analysed for each group and compared. There was a statistically significant difference in JOA evaluation of myelopathy between the groups in group A, the mean JOA score declined from 7.9 to 7.0, i.e., -0.9 point, while in group B it

  17. Chipping machines: disc and drum energy requirements

    Directory of Open Access Journals (Sweden)

    Alessio Facello

    2013-09-01

    Full Text Available Air pollution and fossil fuel reserves exhaustion are increasing the importance of the biomass-derived products, in particular wood, as source of clean and renewable energy for the production of electricity or steam. In order to improve the global efficiency and the entire production chain, we have to evaluate the energetic aspects linked to the process of transformation, handling and transport of these materials. This paper reports results on a comparison between two chippers of similar size using different cutting technology: disc and drum tool respectively. During trials, fuel consumption, PTO torque and speed, processing time and weight of processed material were recorded. Power demand, fuel consumption, specific energy and productivity were computed. The machine was fed with four different feedstock types (chestnut logs, poplar logs, poplar branches, poplar sawmill residues. 15 repetitions for each combination of feedstock-tool were carried out. The results of this study show that the disc tool requires, depending on the processed material, from 12 to 18% less fuel per unit of material processed than the drum tool, and consequently, from 12 to 16% less specific energy. In particular, the highest difference between tools was found in branches processing whereas the smallest was in poplar logs. Furthermore the results of the investigation indicate, that, in testing conditions, the productivity of drum tool is higher (8% than disc tool.

  18. Accretion disc origin of the Earth's water.

    Science.gov (United States)

    Vattuone, Luca; Smerieri, Marco; Savio, Letizia; Asaduzzaman, Abu Md; Muralidharan, Krishna; Drake, Michael J; Rocca, Mario

    2013-07-13

    Earth's water is conventionally believed to be delivered by comets or wet asteroids after the Earth formed. However, their elemental and isotopic properties are inconsistent with those of the Earth. It was thus proposed that water was introduced by adsorption onto grains in the accretion disc prior to planetary growth, with bonding energies so high as to be stable under high-temperature conditions. Here, we show both by laboratory experiments and numerical simulations that water adsorbs dissociatively on the olivine {100} surface at the temperature (approx. 500-1500 K) and water pressure (approx. 10⁻⁸ bar) expected for the accretion disc, leaving an OH adlayer that is stable at least up to 900 K. This may result in the formation of many Earth oceans, provided that a viable mechanism to produce water from hydroxyl exists. This adsorption process must occur in all disc environments around young stars. The inevitable conclusion is that water should be prevalent on terrestrial planets in the habitable zone around other stars.

  19. Mapping of gene mutations in drosophila melanogaster

    OpenAIRE

    Halvorsen, Charlotte Marie

    2004-01-01

    In this experiment, mutant genes of a given unknown mutant strain of Drosophila melanogaster were mapped to specific chromosomes. Drosophila melanogaster, commonly known as the fruit fly, was the appropriate choice for the organism to use in this specific experiment because of its relatively rapid life cycle of 10-14 days and because of the small amount of space and food neccessary for maintaining thousands of flies. The D. Melanogaster unknown strain specifically used in this experiment wa...

  20. Lowering of the YE+3 endcap disc on 30th November

    CERN Multimedia

    Max Brice, CERN

    2006-01-01

    Gigantic disc of CMS detector travels 100 m under the Earth It's an amazing engineering challenge - the lowering of the first tremendous endcap disc, known as YE+3, of the CMS particle detector slowly and carefully 100 m underground into the experimental cavern. The disc is one of 15 large pieces to make the grand descent. It's a uniquely shaped slice, 16 m high, about 50 cm thick and weighing 400 tonnes. The solid steel structure of the disc forms part of the magnet return yoke and is equipped on both sides with muon chambers. A special gantry crane will lower the element, with just 20 cm of leeway between the edges of the detector and the walls of the shaft. CMS is one of the four main experiments that will take data at the world's highest energy particle accelerator, CERN's Large Hadron Collider (LHC). The LHC is a 27 km circular ring 100 m underground. The CMS detector weighs a total of 12 500 tonnes and is constructed on the surface. Once all of the pieces are fully equipped, lowered underground and re-t...

  1. Characterization of Autophagic Responses in Drosophila melanogaster.

    Science.gov (United States)

    Xu, T; Kumar, S; Denton, D

    2017-01-01

    Drosophila is an excellent model system for studying autophagy during animal development due to the availability of genetic reagents and opportunity for in vivo cell biological analysis. The regulation and mechanism of autophagy are highly evolutionarily conserved and the role of autophagy has been characterized during various stages of Drosophila development as well as following starvation. Studies in Drosophila have revealed novel insights into the role of distinct components of the autophagy machinery. This chapter describes protocols for examining autophagy during Drosophila development. A crucial step in the induction of autophagy is the incorporation of Atg8a into the autophagosome. This can be measured as autophagic puncta using live fluorescent imaging, immunostaining, or immunoblot analysis of LC3/Atg8a processing. The level of autophagy can also be examined using other specific components of the autophagy pathway as markers detected by immunofluorescent imaging. Based on the distinct morphology of autophagy, it can also be examined by transmission electron microscopy. In addition, one of the advantages of using Drosophila as a model is the ability to undertake genetic analysis of individual components of the autophagy machinery. Current approaches that can be used to monitor autophagy, including the overall flux and individual steps in Drosophila melanogaster, will be discussed. © 2017 Elsevier Inc. All rights reserved.

  2. Effect of non-nutritive sugars to decrease the survivorship of spotted wing drosophila, Drosophila suzukii

    Science.gov (United States)

    In this study, we investigated the effects of non-nutritive sugars and sugar alcohols on the survivorship of spotted wing drosophila, Drosophila suzukii, and found erythritol and erythrose as potentially toxic to the fly. In a dose-dependent study, erythritol and erythrose significantly reduced fly ...

  3. New record for the invasive Spotted Wing Drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae) in Anillaco, Argentina

    Science.gov (United States)

    The invasive Spotted Wing Drosophila (SWD), Drosophila suzukii Matsumura, is reported for the first time in La Rioja, Argentina. This represents a major range expansion for this species. The natural enemies of SWD, Leptopilina clavipes and Ganaspis hookeri were also collected with the SWD at the s...

  4. Senescent intervertebral disc cells exhibit perturbed matrix homeostasis phenotype.

    Science.gov (United States)

    Ngo, Kevin; Patil, Prashanti; McGowan, Sara J; Niedernhofer, Laura J; Robbins, Paul D; Kang, James; Sowa, Gwendolyn; Vo, Nam

    2017-09-01

    Aging greatly increases the risk for intervertebral disc degeneration (IDD) as a result of proteoglycan loss due to reduced synthesis and enhanced degradation of the disc matrix proteoglycan (PG). How disc matrix PG homeostasis becomes perturbed with age is not known. The goal of this study is to determine whether cellular senescence is a source of this perturbation. We demonstrated that disc cellular senescence is dramatically increased in the DNA repair-deficient Ercc1 -/Δ mouse model of human progeria. In these accelerated aging mice, increased disc cellular senescence is closely associated with the rapid loss of disc PG. We also directly examine PG homeostasis in oxidative damage-induced senescent human cells using an in vitro cell culture model system. Senescence of human disc cells treated with hydrogen peroxide was confirmed by growth arrest, senescence-associated β-galactosidase activity, γH2AX foci, and acquisition of senescence-associated secretory phenotype. Senescent human disc cells also exhibited perturbed matrix PG homeostasis as evidenced by their decreased capacity to synthesize new matrix PG and enhanced degradation of aggrecan, a major matrix PG. of the disc. Our in vivo and in vitro findings altogether suggest that disc cellular senescence is an important driver of PG matrix homeostatic perturbation and PG loss. Published by Elsevier B.V.

  5. Human disc degeneration is associated with increased MMP 7 expression.

    Science.gov (United States)

    Le Maitre, C L; Freemont, A J; Hoyland, J A

    2006-01-01

    During intervertebral disc (IVD) degeneration, normal matrix synthesis decreases and degradation of disc matrix increases. A number of proteases that are increased during disc degeneration are thought to be involved in its pathogenesis. Matrix metalloproteinase 7 (MMP 7) (Matrilysin, PUMP-1) is known to cleave the major matrix molecules found within the IVD, i.e., the proteoglycan aggrecan and collagen type II. To date, however, it is not known how its expression changes with degeneration or its exact location. We investigated the localization of MMP 7 in human, histologically graded, nondegenerate, degenerated and prolapsed discs to ascertain whether MMP 7 is up-regulated during disc degeneration. Samples of human IVD tissue were fixed in neutral buffered formalin, embedded in paraffin, and sections stained with hematoxylin and eosin to score the degree of morphological degeneration. Immunohistochemistry was performed to localize MMP 7 in 41 human IVDs with varying degrees of degeneration. We found that the chondrocyte-like cells of the nucleus pulposus and inner annulus fibrosus were MMP 7 immunopositive; little immunopositivity was observed in the outer annulus. Nondegenerate discs showed few immunopositive cells. A significant increase in the proportion of MMP 7 immunopositive cells was seen in the nucleus pulposus of discs classified as showing intermediate levels of degeneration and a further increase was seen in discs with severe degeneration. Prolapsed discs showed more MMP 7 immunopositive cells compared to nondegenerated discs, but fewer than those seen in cases of severe degeneration.

  6. Place learning overrides innate behaviors in Drosophila.

    Science.gov (United States)

    Baggett, Vincent; Mishra, Aditi; Kehrer, Abigail L; Robinson, Abbey O; Shaw, Paul; Zars, Troy

    2018-03-01

    Animals in a natural environment confront many sensory cues. Some of these cues bias behavioral decisions independent of experience, and action selection can reveal a stimulus-response (S-R) connection. However, in a changing environment it would be a benefit for an animal to update behavioral action selection based on experience, and learning might modify even strong S-R relationships. How animals use learning to modify S-R relationships is a largely open question. Three sensory stimuli, air, light, and gravity sources were presented to individual Drosophila melanogaster in both naïve and place conditioning situations. Flies were tested for a potential modification of the S-R relationships of anemotaxis, phototaxis, and negative gravitaxis by a contingency that associated place with high temperature. With two stimuli, significant S-R relationships were abandoned when the cue was in conflict with the place learning contingency. The role of the dunce ( dnc ) cAMP-phosphodiesterase and the rutabaga ( rut ) adenylyl cyclase were examined in all conditions. Both dnc 1 and rut 2080 mutant flies failed to display significant S-R relationships with two attractive cues, and have characteristically lower conditioning scores under most conditions. Thus, learning can have profound effects on separate native S-R relationships in multiple contexts, and mutation of the dnc and rut genes reveal complex effects on behavior. © 2018 Baggett et al.; Published by Cold Spring Harbor Laboratory Press.

  7. Mechanoreceptors in Diseased Cervical Intervertebral Disc and Vertigo.

    Science.gov (United States)

    Yang, Liang; Yang, Cheng; Pang, Xiaodong; Li, Duanming; Yang, Hong; Zhang, Xinwu; Yang, Yi; Peng, Baogan

    2017-04-15

    We collected the samples of cervical intervertebral discs from patients with vertigo to examine the distribution and types of mechanoreceptors in diseased cervical disc. The aim of this study was to determine whether mechanoreceptors are distributed more abundantly in cervical discs from patients with cervical spondylosis, and whether they are related to vertigo. Previous limited studies have found that normal cervical intervertebral discs are supplied with mechanoreceptors that have been considered responsible for proprioceptive functions. Several clinical studies have indicated that the patients with cervical spondylosis manifested significantly impaired postural control and subjective balance disturbance. We collected 77 samples of cervical discs from 62 cervical spondylosis patients without vertigo, 61 samples from 54 patients with vertigo, and 40 control samples from 8 cadaveric donors to investigate distribution of mechanoreceptors containing neurofilament (NF200) and S-100 protein immunoreactive nerve endings. The immunohistochemical investigation revealed that the most frequently encountered mechanoreceptors were the Ruffini corpuscles in all groups of cervical disc samples. They were obviously increased in the number and deeply ingrown into inner annulus fibrosus and even into nucleus pulposus in the diseased cervical discs from patients with vertigo in comparison with the discs from patients without vertigo and control discs. Only three Golgi endings were seen in the three samples from patients with vertigo. No Pacinian corpuscles were found in any samples of cervical discs. The diseased cervical discs from patients with vertigo had more abundant distribution of Ruffini corpuscles than other discs. A positive association between the increased number and ingrowth of Ruffini corpuscles in the diseased cervical disc and the incidence of vertigo in the patients with cervical spondylosis was found, which may indicate a key role of Ruffini corpuscles in the

  8. Identification of four Drosophila allatostatins as the cognate ligands for the Drosophila orphan receptor DAR-2

    DEFF Research Database (Denmark)

    Lenz, C; Williamson, M; Hansen, G N

    2001-01-01

    The allatostatins are generally inhibitory insect neuropeptides. The Drosophila orphan receptor DAR-2 is a G-protein-coupled receptor, having 47% amino acid residue identity with another Drosophila receptor, DAR-1 (which is also called dros. GPCR, or DGR) that was previously shown...... to be the receptor for an intrinsic Drosophila A-type (cockroach-type) allatostatin. Here, we have permanently expressed DAR-2 in CHO cells and found that it is the cognate receptor for four Drosophila A-type allatostatins, the drostatins-A1 to -A4. Of all the drostatins, drostatin-A4 (Thr...... weakly in the brain. The Drosophila larval gut also contains about 20-30 endocrine cells, expressing the gene for the drostatins-A1 to -A4. We suggest, therefore, that DAR-2 mediates an allatostatin (drostatin)-induced inhibition of gut motility. This is the first report on the permanent and functional...

  9. The Causal Connection Between Disc and Power-Law Variability in Hard State Black Hole X-Ray Binaries

    Science.gov (United States)

    Uttley, P.; Wilkinson, T.; Cassatella, P.; Wilms, J.; Pottschimdt, K.; Hanke, M.; Boeck, M.

    2010-01-01

    We use the XMM-Newton EPIC-pn instrument in timing mode to extend spectral time-lag studies of hard state black hole X-ray binaries into the soft X-ray band. \\Ve show that variations of the disc blackbody emission substantially lead variations in the power-law emission, by tenths of a second on variability time-scales of seconds or longer. The large lags cannot be explained by Compton scattering but are consistent with time-delays due to viscous propagation of mass accretion fluctuations in the disc. However, on time-scales less than a second the disc lags the power-law variations by a few ms, consistent with the disc variations being dominated by X-ray heating by the power-law, with the short lag corresponding to the light-travel time between the power-law emitting region and the disc. Our results indicate that instabilities in the accretion disc are responsible for continuum variability on time-scales of seconds or longer and probably also on shorter time-scales.

  10. Total disc replacement using tissue-engineered intervertebral discs in the canine cervical spine.

    Directory of Open Access Journals (Sweden)

    Yu Moriguchi

    Full Text Available The most common reason that adults in the United States see their physician is lower back or neck pain secondary to degenerative disc disease. To date, approaches to treat degenerative disc disease are confined to purely mechanical devices designed to either eliminate or enable flexibility of the diseased motion segment. Tissue engineered intervertebral discs (TE-IVDs have been proposed as an alternative approach and have shown promise in replacing native IVD in the rodent tail spine. Here we demonstrate the efficacy of our TE-IVDs in the canine cervical spine. TE-IVD components were constructed using adult canine annulus fibrosis and nucleus pulposus cells seeded into collagen and alginate hydrogels, respectively. Seeded gels were formed into a single disc unit using molds designed from the geometry of the canine spine. Skeletally mature beagles underwent discectomy with whole IVD resection at levels between C3/4 and C6/7, and were then divided into two groups that received only discectomy or discectomy followed by implantation of TE-IVD. Stably implanted TE-IVDs demonstrated significant retention of disc height and physiological hydration compared to discectomy control. Both 4-week and 16-week histological assessments demonstrated chondrocytic cells surrounded by proteoglycan-rich matrices in the NP and by fibrocartilaginous matrices in the AF portions of implanted TE-IVDs. Integration into host tissue was confirmed over 16 weeks without any signs of immune reaction. Despite the significant biomechanical demands of the beagle cervical spine, our stably implanted TE-IVDs maintained their position, structure and hydration as well as disc height over 16 weeks in vivo.

  11. Effect of Hawthorn on Drosophila Melanogaster Antioxidant-Related ...

    African Journals Online (AJOL)

    Results: The results indicate that hawthorn extract prolonged the life span of Drosophila, with 50 % survival time of 0.8 ... Drosophila's aging gene is highly similar to humans [4,5]. ..... reduces lipid peroxidation in senescence-accelerated mice .

  12. Describing a new syndrome in L5-S1 disc herniation: Sexual and sphincter dysfunction without pain and muscle weakness

    Directory of Open Access Journals (Sweden)

    Nezih Akca

    2014-01-01

    Full Text Available Context: Little seems to be known about the sexual dysfunction (SD in lumbar intervertebral disc herniation. Aims: Investigation of sexual and sphincter dysfunction in patient with lumbar disc hernitions. Settings and Design: A retrospective analysis. Materials and Methods: Sexual and sphincter dysfunction in patients admitted with lumbar disc herniations between September 2012-March 2014. Statistical Analysis Used: Statistical analysis was performed using the Predictive Analytics SoftWare (PASW Statistics 18.0 for Windows (Statistical Package for the Social Sciences, SPSS Inc., Chicago, Illinois. The statistical significance was set at P < 0.05. The Wilcoxon signed ranks test was used to evaluate the difference between patients. Results: Four patients with sexual and sphincter dysfunction were found, including two women and two men, aged between 20 and 52 years. All of them admitted without low back pain. In addition, on neurological examination, reflex and motor deficit were not found. However, almost all patients had perianal sensory deficit and sexual and sphincter dysfunction. Magnetic resonance imaging (MRI of three patients displayed a large extruded disc fragment at L5-S1 level on the left side. In fourth patient, there were not prominent disc herniations. There was not statistically significant difference between pre-operative and post-operative sexual function, anal-urethral sphincter function, and perianal sensation score. A syndrome in L5-S1 disc herniation with sexual and sphincter dysfunction without pain and muscle weakness was noted. We think that it is crucial for neurosurgeons to early realise that paralysis of the sphincter and sexual dysfunction are possible in patients with lumbar L5-S1 disc disease. Conclusion: A syndrome with perianal sensory deficit, paralysis of the sphincter, and sexual dysfunction may occur in patients with lumbar L5-S1 disc disease. The improvement of perianal sensory deficit after surgery was

  13. Gustatory Processing in Drosophila melanogaster.

    Science.gov (United States)

    Scott, Kristin

    2018-01-07

    The ability to identify nutrient-rich food and avoid toxic substances is essential for an animal's survival. Although olfaction and vision contribute to food detection, the gustatory system acts as a final checkpoint control for food acceptance or rejection. The vinegar fly Drosophila melanogaster tastes many of the same stimuli as mammals and provides an excellent model system for comparative studies of taste detection. The relative simplicity of the fly brain and behaviors, along with the molecular genetic and functional approaches available in this system, allow the examination of gustatory neural circuits from sensory input to motor output. This review discusses the molecules and cells that detect taste compounds in the periphery and the circuits that process taste information in the brain. These studies are providing insight into how the detection of taste compounds regulates feeding decisions.

  14. The stellar metallicity gradients in galaxy discs in a cosmological scenario

    Science.gov (United States)

    Tissera, Patricia B.; Machado, Rubens E. G.; Sanchez-Blazquez, Patricia; Pedrosa, Susana E.; Sánchez, Sebastián F.; Snaith, Owain; Vilchez, Jose

    2016-08-01

    Context. The stellar metallicity gradients of disc galaxies provide information on disc assembly, star formation processes, and chemical evolution. They also might store information on dynamical processes that could affect the distribution of chemical elements in the gas phase and the stellar components. Understanding their joint effects within a hierarchical clustering scenario is of paramount importance. Aims: We studied the stellar metallicity gradients of simulated discs in a cosmological simulation. We explored the dependence of the stellar metallicity gradients on stellar age and on the size and mass of the stellar discs. Methods: We used a catalogue of galaxies with disc components selected from a cosmological hydrodynamical simulation performed including a physically motivated supernova feedback and chemical evolution. Disc components were defined based on angular momentum and binding energy criteria. The metallicity profiles were estimated for stars with different ages. We confront our numerical findings with results from the Calar Alto Legacy Integral Field Area (CALIFA) Survey. Results: The simulated stellar discs are found to have metallicity profiles with slopes in global agreement with observations. Low stellar mass galaxies tend to have a larger variety of metallicity slopes. When normalized by the half-mass radius, the stellar metallicity gradients do not show any dependence and the dispersion increases significantly, regardless of the galaxy mass. Galaxies with stellar masses o f around 1010M⊙ show steeper negative metallicity gradients. The stellar metallicity gradients correlate with the half-mass radius. However, the correlation signal is not present when they are normalized by the half-mass radius. Stellar discs with positive age gradients are detected to have negative and positive metallicity gradients, depending on the relative importance of recent star formation activity in the central regions. Conclusions: Our results suggest that inside

  15. Single Nucleotide Polymorphism Markers for Genetic Mapping in Drosophila melanogaster

    OpenAIRE

    Hoskins, Roger A.; Phan, Alexander C.; Naeemuddin, Mohammed; Mapa, Felipa A.; Ruddy, David A.; Ryan, Jessica J.; Young, Lynn M.; Wells, Trent; Kopczynski, Casey; Ellis, Michael C.

    2001-01-01

    For nearly a century, genetic analysis in Drosophila melanogaster has been a powerful tool for analyzing gene function, yet Drosophila lacks the molecular genetic mapping tools that recently have revolutionized human, mouse, and plant genetics. Here, we describe the systematic characterization of a dense set of molecular markers in Drosophila by using a sequence tagged site-based physical map of the genome. We identify 474 biallelic markers in standard laboratory strains of Drosophila that sp...

  16. Identification of the Drosophila eIF4A gene as a target of the DREF transcription factor

    International Nuclear Information System (INIS)

    Ida, Hiroyuki; Yoshida, Hideki; Nakamura, Kumi; Yamaguchi, Masamitsu

    2007-01-01

    The DNA replication-related element-binding factor (DREF) regulates cell proliferation-related gene expression in Drosophila. We have carried out a genetic screening, taking advantage of the rough eye phenotype of transgenic flies that express full-length DREF in the eye imaginal discs and identified the eukaryotic initiation factor 4A (eIF4A) gene as a dominant suppressor of the DREF-induced rough eye phenotype. The eIF4A gene was here found to carry three DRE sequences, DRE1 (- 40 to - 47), DRE2 (- 48 to - 55), and DRE3 (- 267 to - 274) in its promoter region, these all being important for the eIF4A gene promoter activity in cultured Drosophila Kc cells and in living flies. Knockdown of DREF in Drosophila S2 cells decreased the eIF4A mRNA level and the eIF4A gene promoter activity. Furthermore, specific binding of DREF to genomic regions containing DRE sequences was demonstrated by chromatin immunoprecipitation assays using anti-DREF antibodies. Band mobility shift assays using Kc cell nuclear extracts revealed that DREF could bind to DRE1 and DRE3 sequences in the eIF4A gene promoter in vitro, but not to the DRE2 sequence. The results suggest that the eIF4A gene is under the control of the DREF pathway and DREF is therefore involved in the regulation of protein synthesis

  17. Two distinct E3 ubiquitin ligases have complementary functions in the regulation of delta and serrate signaling in Drosophila.

    Directory of Open Access Journals (Sweden)

    Roland Le Borgne

    2005-04-01

    Full Text Available Signaling by the Notch ligands Delta (Dl and Serrate (Ser regulates a wide variety of essential cell-fate decisions during animal development. Two distinct E3 ubiquitin ligases, Neuralized (Neur and Mind bomb (Mib, have been shown to regulate Dl signaling in Drosophila melanogaster and Danio rerio, respectively. While the neur and mib genes are evolutionarily conserved, their respective roles in the context of a single organism have not yet been examined. We show here that the Drosophila mind bomb (D-mib gene regulates a subset of Notch signaling events, including wing margin specification, leg segmentation, and vein determination, that are distinct from those events requiring neur activity. D-mib also modulates lateral inhibition, a neur- and Dl-dependent signaling event, suggesting that D-mib regulates Dl signaling. During wing development, expression of D-mib in dorsal cells appears to be necessary and sufficient for wing margin specification, indicating that D-mib also regulates Ser signaling. Moreover, the activity of the D-mib gene is required for the endocytosis of Ser in wing imaginal disc cells. Finally, ectopic expression of neur in D-mib mutant larvae rescues the wing D-mib phenotype, indicating that Neur can compensate for the lack of D-mib activity. We conclude that D-mib and Neur are two structurally distinct proteins that have similar molecular activities but distinct developmental functions in Drosophila.

  18. Schrödinger evolution of self-gravitating discs

    Science.gov (United States)

    Batygin, Konstantin

    2018-04-01

    An understanding of the long-term evolution of self-gravitating discs ranks among the classic outstanding problems of astrophysics. In this work, we show that the secular inclination dynamics of a geometrically thin quasi-Keplerian disc, with a surface density profile that scales as the inverse square-root of the orbital radius, are described by the time-dependent Schrödinger equation. Within the context of this formalism, nodal bending waves correspond to the eigenmodes of a quasi-particle's wavefunction, confined in an infinite square well with boundaries given by the radial extent of the disc. We further show that external secular perturbations upon self-gravitating discs exhibit a mathematical similarity to quantum scattering theory. Employing this framework, we derive an analytic criterion for the gravitational rigidity of a nearly-Keplerian disc under external perturbations. Applications of the theory to circumstellar discs and Galactic nuclei are discussed.

  19. Indigenous development of rupture discs for FBTR (Paper No. 028)

    International Nuclear Information System (INIS)

    Chetal, S.C.; Raju, Chander; Anandkumar, V.; Seetharaman, V.

    1987-02-01

    Rupture discs are required as a safety device for protecting the secondary sodium circuit and its components against high pressure surges due to accidental water-steam leaks in sodium heated steam generator and the consequent sodium water reaction. For identical reasons, rupture discs are also required on the vessels used for decontamination of sodium components. As an import substitution of the costly items for the FBTR Project, development of the rupture disc assemblies has been in progress at Indira Gandhi Centre for Atomic Research, Kalpakkam. Reverse buckling knife blade concept with stainless steel disc has been taken up for development. Hydroforming process without any die has been selected for disc fabrication. One rupture disc assembly required for steam generator has been tested in sodium satisfactorily. (author). 4 tables, 5 figs

  20. Cervical artificial disc extrusion after a paragliding accident

    OpenAIRE

    Niu, Tianyi; Hoffman, Haydn; Lu, Daniel C.

    2017-01-01

    Background: Cervical total disc replacement (TDR) is an established alternative to anterior cervical discectomy and fusion (ACDF) with excellent long-term outcomes and low failure rates. Cases of implant failure and migration are scarce and primarily limited to several years postoperatively. The authors report a case of anterior extrusion of a C4-C5 ProDisc-C (DePuy Synthes, West Chester, PA, USA) cervical artificial disc (CAD) 14 months after placement due to minor trauma. Case Description: ...

  1. Thoracic spine disc-related abnormalities: longitudinal MR imaging assessment

    Energy Technology Data Exchange (ETDEWEB)

    Girard, Charles J.; Schweitzer, Mark E.; Morrison, William B.; Parellada, Joan A. [TJUH Radiology, Philadelphia, Pennsylvania (United States); Carrino, J.A. [Department of Radiology ASB-1, Harvard Medical School, Brigham and Women' s Hospital, L1, Room 002B, 75 Francis Street, MA 02115, Boston (United States)

    2004-04-01

    To describe and characterize the temporal changes in disc-related disorders of the thoracic spine using MR imaging. A retrospective longitudinal cohort study was carried out of 40 patients with two sequential thoracic spine MR images at variable intervals. The images were assessed for baseline presence of, new incidence of and changes in disc herniation, degenerative disc disease, endplate marrow signal alteration and Schmorl nodes. The range of follow-up was 4-149 weeks. Baseline presence was: disc herniation, 10% (49/480); degenerative disc disease, 14% (66/480); endplate marrow signal alteration, 2.3% (11/480); Schmorl nodes 9.6% (46/480). Most pre-existing lesions tended to remain unchanged. Herniations showed the most change, tending to improve in 27%. New incidence was: disc herniation, 1.5% (7/480), degenerative disc disease, 2% (10/480); endplate marrow signal alteration, 1.6% (8/480); Schmorl nodes, 2.1% (10/480). Disc degeneration was first visible at an 11-week interval and once established almost never changed over many weeks to months. Endplate signal alterations (Modic changes) were uncommon. Schmorl nodes show no change from baseline for up to 2 1/2 years. All findings predominated in the lower intervertebral levels from T6 to T10. The most prevalent thoracic spine disc-related findings are degeneration and herniation. Disc herniations predominate in the lower segments and are a dynamic phenomenon. Disc degeneration can be rapidly evolving but tends to remain unchanged after occurrence. Endplate marrow signal changes were an uncommon manifestation of thoracic disc disease. Schmorl nodes showed the least change over time. (orig.)

  2. Collimation of particle beams from thick accretion discs

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M [N. Copernicus Astronomical Center, Warszawa (Poland); Wilson, D B [Cambridge Univ. (UK). Inst. of Astronomy

    1981-11-01

    The acceleration and collimation of particle beams in the funnel of thick accretion discs is studied in the approximation that the flow is optically thin. Such flows can be collimated to within approximately 0.1 radians by sufficiently thick discs. The flow cannot convert more than a small fraction of the disc's (super-Eddington) luminosity into the energy flow of a narrow beam without being optically thick.

  3. New Brown Dwarf Discs in Upper Scorpius Observed with WISE

    Science.gov (United States)

    Dawson, P.; Scholz, A.; Ray, T. P.; Natta, A.; Marsh, K. A.; Padgett, D.; Ressler, M. E.

    2013-01-01

    We present a census of the disc population for UKIDSS selected brown dwarfs in the 5-10 Myr old Upper Scorpius OB association. For 116 objects originally identified in UKIDSS, the majority of them not studied in previous publications, we obtain photometry from the Wide-Field Infrared Survey Explorer data base. The resulting colour magnitude and colour colour plots clearly show two separate populations of objects, interpreted as brown dwarfs with discs (class II) and without discs (class III). We identify 27 class II brown dwarfs, 14 of them not previously known. This disc fraction (27 out of 116, or 23%) among brown dwarfs was found to be similar to results for K/M stars in Upper Scorpius, suggesting that the lifetimes of discs are independent of the mass of the central object for low-mass stars and brown dwarfs. 5 out of 27 discs (19 per cent) lack excess at 3.4 and 4.6 microns and are potential transition discs (i.e. are in transition from class II to class III). The transition disc fraction is comparable to low-mass stars.We estimate that the time-scale for a typical transition from class II to class III is less than 0.4 Myr for brown dwarfs. These results suggest that the evolution of brown dwarf discs mirrors the behaviour of discs around low-mass stars, with disc lifetimes of the order of 5 10 Myr and a disc clearing time-scale significantly shorter than 1 Myr.

  4. ISASS Policy Statement – Lumbar Artificial Disc

    Science.gov (United States)

    Garcia, Rolando

    2015-01-01

    Purpose The primary goal of this Policy Statement is to educate patients, physicians, medical providers, reviewers, adjustors, case managers, insurers, and all others involved or affected by insurance coverage decisions regarding lumbar disc replacement surgery. Procedures This Policy Statement was developed by a panel of physicians selected by the Board of Directors of ISASS for their expertise and experience with lumbar TDR. The panel's recommendation was entirely based on the best evidence-based scientific research available regarding the safety and effectiveness of lumbar TDR. PMID:25785243

  5. Frictional Torque on a Rotating Disc

    Science.gov (United States)

    2012-01-01

    Tracker Eur. J. Phys. 33 615–22 [2] Alam J, Hassan H, Shamim S , Mahmood W and Anwar M S 2011 Precise measurement of velocity dependent friction in...on a rotating disc 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT...NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) US Naval Academy,Physics Department,Annapolis,MD,21402-1363 8. PERFORMING ORGANIZATION

  6. ISO science - observations of dusty discs.

    Science.gov (United States)

    Heske, A.

    1992-12-01

    ISO, the Infrared Space Observatory, will be an infrared observing facility in space. Via submission of observing proposals, use of this facility will be open to the astronomical community. The scientific payload consists of two spectrometers, a camera and a photo-polarimeter. Following an overview of the ISO mission, this paper describes the highlights of the Central Programme - proposals which are being prepared by the instrument groups, the mission scientists and the astronomers of the ISO Science Operations Team - with special emphasis on the proposals concerned with dusty discs.

  7. Angular Speed of a Compact Disc

    Science.gov (United States)

    Sawicki, Mikolaj ``Mik''

    2006-09-01

    A spinning motion of a compact disc in a CD player offers an interesting and challenging problem in rotational kinematics with a nonconstant angular acceleration that can be incorporated into a typical introductory physics class for engineers and scientists. It can be used either as an example presented during the lecture, emphasizing application of calculus, or as a homework assignment that could be handled easily with the help of a spreadsheet, thus eliminating the calculus aspect altogether. I tried both approaches, and the spreadsheet study was favored by my students.

  8. Power diagrams and interaction processes for unions of discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, Katarina

    We study a flexible class of finite disc process models with interaction between the discs. We let U denote the random set given by the union of discs, and use for the disc process an exponential family density with the canonical sufficient statistic only depending on geometric properties of U......, becomes useful for handling the problem of edge effects when only U is observed within a bounded observation window. The power tessellation and its dual graph become major tools when establishing inclusion-exclusion formulae, formulae for computing geometric characteristics of U, and stability properties...

  9. Power diagrams and interaction processes for unions of discs

    DEFF Research Database (Denmark)

    Møller, Jesper; Helisova, Katerina

    2008-01-01

     We study a flexible class of finite-disc process models with interaction between the discs. We let U denote the random set given by the union of discs, and use for the disc process an exponential family density with the canonical sufficient statistic depending only on geometric properties of U......, becomes useful for handling the problem of edge effects when only U is observed within a bounded observation window. The power tessellation and its dual graph become major tools when establishing inclusion-exclusion formulae, formulae for computing geometric characteristics of U, and stability properties...

  10. Disc electrophoresis and related techniques of polyacrylamide gel electrophoresis

    National Research Council Canada - National Science Library

    Maurer, H. R

    1971-01-01

    ..., enzymes, antingens and radioactively labelled materials, and detailed treatments of micro disc electrophoresis, preparative polyacrylamide gel electrophoresis and many other techniques for special problems...

  11. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    International Nuclear Information System (INIS)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-01-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach. (orig.)

  12. CT reconstruction technique in lumbar intraneuroforaminal disc herniation

    Energy Technology Data Exchange (ETDEWEB)

    Volle, E.; Claussen, C.; Kern, A.; Stoltenburg, G.

    1988-04-01

    The CT appearance of the lumbar neural foramina and contents is described in detail and compared to histopathological specimens. Direct axial scans with secondary sagittal, coronal and paraxial reconstruction series of slices of the neuralforamen were derived from lumbar spine examination of fifty normal adults. These normal parameters were then used to evaluate and subdivide 20 patients with disc herniation involving the neuralforamen. The new paraxial reformation was able to show an intraneuroforaminal disc involvement. CT-reformation technique and operative results in intraneuroforaminal disc herniation correspond in 80%. This improvement in preoperative diagnosis demonstrates to the neurosurgeon the full extent of disc herniation and results in an optimized operative approach.

  13. Vascular complications of prosthetic inter-vertebral discs.

    Science.gov (United States)

    Daly, Kevin J; Ross, E Raymond S; Norris, Heather; McCollum, Charles N

    2006-10-01

    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had eroded into the bifurcation of the inferior vena cava and the left common iliac vein. In three cases the aortic bifurcation was also involved. The fibrosis was so severe that dissecting out the arteries and veins to provide access to the relevant disc proved impossible. Formal division of the left common iliac vein and artery with subsequent repair was our solution. Anterior inter-vertebral disc displacement was associated with severe vascular injury. Preventing anterior disc displacement is essential in disc design. In the event of anterior displacement, disc removal should be planned with a Vascular Surgeon.

  14. Metallicity gradient of the thick disc progenitor at high redshift

    Science.gov (United States)

    Kawata, Daisuke; Allende Prieto, Carlos; Brook, Chris B.; Casagrande, Luca; Ciucă, Ioana; Gibson, Brad K.; Grand, Robert J. J.; Hayden, Michael R.; Hunt, Jason A. S.

    2018-01-01

    We have developed a novel Markov Chain Monte Carlo chemical 'painting' technique to explore possible radial and vertical metallicity gradients for the thick disc progenitor. In our analysis, we match an N-body simulation to the data from the Apache Point Observatory Galactic Evolution Experiment survey. We assume that the thick disc has a constant scaleheight and has completed its formation at an early epoch, after which time radial mixing of its stars has taken place. Under these assumptions, we find that the initial radial metallicity gradient of the thick disc progenitor should not be negative, but either flat or even positive, to explain the current negative vertical metallicity gradient of the thick disc. Our study suggests that the thick disc was built-up in an inside-out and upside-down fashion, and older, smaller and thicker populations are more metal poor. In this case, star-forming discs at different epochs of the thick disc formation are allowed to have different radial metallicity gradients, including a negative one, which helps to explain a variety of slopes observed in high-redshift disc galaxies. This scenario helps to explain the positive slope of the metallicity-rotation velocity relation observed for the Galactic thick disc. On the other hand, radial mixing flattens the slope of an existing gradient.

  15. Notochord Cells in Intervertebral Disc Development and Degeneration

    Science.gov (United States)

    McCann, Matthew R.; Séguin, Cheryle A.

    2016-01-01

    The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches. PMID:27252900

  16. Notochord Cells in Intervertebral Disc Development and Degeneration

    Directory of Open Access Journals (Sweden)

    Matthew R. McCann

    2016-01-01

    Full Text Available The intervertebral disc is a complex structure responsible for flexibility, multi-axial motion, and load transmission throughout the spine. Importantly, degeneration of the intervertebral disc is thought to be an initiating factor for back pain. Due to a lack of understanding of the pathways that govern disc degeneration, there are currently no disease-modifying treatments to delay or prevent degenerative disc disease. This review presents an overview of our current understanding of the developmental processes that regulate intervertebral disc formation, with particular emphasis on the role of the notochord and notochord-derived cells in disc homeostasis and how their loss can result in degeneration. We then describe the role of small animal models in understanding the development of the disc and their use to interrogate disc degeneration and associated pathologies. Finally, we highlight essential development pathways that are associated with disc degeneration and/or implicated in the reparative response of the tissue that might serve as targets for future therapeutic approaches.

  17. Mechanical design criteria for intervertebral disc tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2010-04-19

    Due to the inability of current clinical practices to restore function to degenerated intervertebral discs, the arena of disc tissue engineering has received substantial attention in recent years. Despite tremendous growth and progress in this field, translation to clinical implementation has been hindered by a lack of well-defined functional benchmarks. Because successful replacement of the disc is contingent upon replication of some or all of its complex mechanical behaviors, it is critically important that disc mechanics be well characterized in order to establish discrete functional goals for tissue engineering. In this review, the key functional signatures of the intervertebral disc are discussed and used to propose a series of native tissue benchmarks to guide the development of engineered replacement tissues. These benchmarks include measures of mechanical function under tensile, compressive, and shear deformations for the disc and its substructures. In some cases, important functional measures are identified that have yet to be measured in the native tissue. Ultimately, native tissue benchmark values are compared to measurements that have been made on engineered disc tissues, identifying where functional equivalence was achieved, and where there remain opportunities for advancement. Several excellent reviews exist regarding disc composition and structure, as well as recent tissue engineering strategies; therefore this review will remain focused on the functional aspects of disc tissue engineering. Copyright 2009 Elsevier Ltd. All rights reserved.

  18. Developments in intervertebral disc disease research: pathophysiology, mechanobiology, and therapeutics.

    Science.gov (United States)

    Weber, Kathryn T; Jacobsen, Timothy D; Maidhof, Robert; Virojanapa, Justin; Overby, Chris; Bloom, Ona; Quraishi, Shaheda; Levine, Mitchell; Chahine, Nadeen O

    2015-03-01

    Low back pain is a leading cause of disability worldwide and the second most common cause of physician visits. There are many causes of back pain, and among them, disc herniation and intervertebral disc degeneration are the most common diagnoses and targets for intervention. Currently, clinical treatment outcomes are not strongly correlated with diagnoses, emphasizing the importance for characterizing more completely the mechanisms of degeneration and their relationships with symptoms. This review covers recent studies elucidating cellular and molecular changes associated with disc mechanobiology, as it relates to degeneration and regeneration. Specifically, we review findings on the biochemical changes in disc diseases, including cytokines, chemokines, and proteases; advancements in disc disease diagnostics using imaging modalities; updates on studies examining the response of the intervertebral disc to injury; and recent developments in repair strategies, including cell-based repair, biomaterials, and tissue engineering. Findings on the effects of the omega-6 fatty acid, linoleic acid, on nucleus pulposus tissue engineering are presented. Studies described in this review provide greater insights into the pathogenesis of disc degeneration and may define new paradigms for early or differential diagnostics of degeneration using new techniques such as systemic biomarkers. In addition, research on the mechanobiology of disease enriches the development of therapeutics for disc repair, with potential to diminish pain and disability associated with disc degeneration.

  19. Acupuncture and Spontaneous Regression of a Radiculopathic Cervical Herniated Disc

    Directory of Open Access Journals (Sweden)

    Kim Sung-Ha

    2012-06-01

    Full Text Available The spontaneous regression of herniated cervical discs is not a well-established phenomenon. However, we encountered a case of a spontaneous regression of a severe radiculopathic herniated cervical disc that was treated with acupuncture, pharmacopuncture, and herb medicine. The symptoms were improved within 12 months of treatment. Magnetic resonance imaging (MRI conducted at that time revealed marked regression of the herniated disc. This case provides an additional example of spontaneous regression of a herniated cervical disc documented by MRI following non-surgical treatment.

  20. Lipoproteins in Drosophila melanogaster—Assembly, Function, and Influence on Tissue Lipid Composition

    Science.gov (United States)

    Palm, Wilhelm; Sampaio, Julio L.; Brankatschk, Marko; Carvalho, Maria; Mahmoud, Ali; Shevchenko, Andrej; Eaton, Suzanne

    2012-01-01

    Interorgan lipid transport occurs via lipoproteins, and altered lipoprotein levels correlate with metabolic disease. However, precisely how lipoproteins affect tissue lipid composition has not been comprehensively analyzed. Here, we identify the major lipoproteins of Drosophila melanogaster and use genetics and mass spectrometry to study their assembly, interorgan trafficking, and influence on tissue lipids. The apoB-family lipoprotein Lipophorin (Lpp) is the major hemolymph lipid carrier. It is produced as a phospholipid-rich particle by the fat body, and its secretion requires Microsomal Triglyceride Transfer Protein (MTP). Lpp acquires sterols and most diacylglycerol (DAG) at the gut via Lipid Transfer Particle (LTP), another fat body-derived apoB-family lipoprotein. The gut, like the fat body, is a lipogenic organ, incorporating both de novo–synthesized and dietary fatty acids into DAG for export. We identify distinct requirements for LTP and Lpp-dependent lipid mobilization in contributing to the neutral and polar lipid composition of the brain and wing imaginal disc. These studies define major routes of interorgan lipid transport in Drosophila and uncover surprising tissue-specific differences in lipoprotein lipid utilization. PMID:22844248

  1. Activated Cdc42 kinase regulates Dock localization in male germ cells during Drosophila spermatogenesis.

    Science.gov (United States)

    Abdallah, Abbas M; Zhou, Xin; Kim, Christine; Shah, Kushani K; Hogden, Christopher; Schoenherr, Jessica A; Clemens, James C; Chang, Henry C

    2013-06-15

    Deregulation of the non-receptor tyrosine kinase ACK1 (Activated Cdc42-associated kinase) correlates with poor prognosis in cancers and has been implicated in promoting metastasis. To further understand its in vivo function, we have characterized the developmental defects of a null mutation in Drosophila Ack, which bears a high degree of sequence similarity to mammalian ACK1 but lacks a CRIB domain. We show that Ack, while not essential for viability, is critical for sperm formation. This function depends on Ack tyrosine kinase activity and is required cell autonomously in differentiating male germ cells at or after the spermatocyte stage. Ack associates predominantly with endocytic clathrin sites in spermatocytes, but disruption of Ack function has no apparent effect on clathrin localization and receptor-mediated internalization of Boss (Bride of sevenless) protein in eye discs. Instead, Ack is required for the subcellular distribution of Dock (dreadlocks), the Drosophila homolog of the SH2- and SH3-containing adaptor protein Nck. Moreover, Dock forms a complex with Ack, and the localization of Dock in male germ cells depends on its SH2 domain. Together, our results suggest that Ack-dependent tyrosine phosphorylation recruits Dock to promote sperm differentiation. Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Beyond the standard model of the disc-line spectral profiles from black hole accretion discs

    Czech Academy of Sciences Publication Activity Database

    Sochora, Vjačeslav; Karas, Vladimír; Svoboda, Jiří; Dovčiak, Michal

    2014-01-01

    Roč. 54, č. 4 (2014), s. 301-304 ISSN 1210-2709 R&D Projects: GA ČR(CZ) GC13-00070J Institutional support: RVO:67985815 Keywords : accretion discs * black hole physics * galactic nuclei Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  3. Inner disc obscuration in GRS 1915+105 based on relativistic slim disc model

    Czech Academy of Sciences Publication Activity Database

    Vierdayanti, K.; Sądowski, A.; Mineshige, L.S.; Bursa, Michal

    2013-01-01

    Roč. 436, č. 1 (2013), s. 71-81 ISSN 0035-8711 Institutional support: RVO:67985815 Keywords : accretion discs * black hole physics * GRS 1915+105 Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.226, year: 2013

  4. Confirming chemical clocks: asteroseismic age dissection of the Milky Way disc(s)

    DEFF Research Database (Denmark)

    Silva Aguirre, V.; Bojsen-Hansen, M.; Slumstrup, D.

    2018-01-01

    Investigations of the origin and evolution of the Milky Way disc have long relied on chemical and kinematic identifications of its components to reconstruct our Galactic past. Difficulties in determining precise stellar ages have restricted most studies to small samples, normally confined to the ...

  5. Analysis of rabbit intervertebral disc physiology based on water metabolism. II. Changes in normal intervertebral discs under axial vibratory load

    International Nuclear Information System (INIS)

    Hirano, N.; Tsuji, H.; Ohshima, H.; Kitano, S.; Itoh, T.; Sano, A.

    1988-01-01

    Metabolic changes induced by axial vibratory load to the spine were investigated based on water metabolism in normal intervertebral discs of rabbits with or without pentobarbital anesthesia. Tritiated water concentration in the intervertebral discs of unanesthetized rabbits was reduced remarkably by axial vibration for 30 minutes using the vibration machine developed for this study. Repeated vibratory load for 18 and 42 hours duration showed the recovery of 3 H 2 O concentration of the intervertebral disc without anesthesia. Computer simulation suggested a reduction of blood flow surrounding the intervertebral disc following the vibration stress. However, no reduction of the 3 H 2 O concentration in the intervertebral disc was noted under anesthesia. Emotional stress cannot be excluded as a factor in water metabolism in the intervertebral disc

  6. [Longterm results of cervical arthroplasty with disc prosthesis. A literature review].

    Science.gov (United States)

    Fransen, P; Schils, F

    2014-01-01

    Cervical arthroplasty has now been performed for over 10 years. Despite the large number of implanted artificial discs, the quality of the published studies is weak, and very few report a follow up exceeding two years. We reviewed the literature on cervical total disc replacement, focusing on publications reporting a follow-up of more than two years. The selection of patients, the type of implant and the surgical technique seem to influence greatly the quality of the clinical and radiological results. The occurrence of heterotopic ossifications around the implant seems to be the rule rather than the exception. Wear debris are likely to be observed in the vicinity of the prosthesis. Most long term studies also report a progressive decrease in the range of motion of the prosthesis, although without influence on the clinical evolution. It seems reasonable to say that cervical disc prosthesis is not inferior to discectomy and fusion, and that these implants allow a short term preservation of cervical mobility, but the efficacy in preventing adjacent segment disease or a favourable costleffectiveness ratio have yet to be demonstrated. A more widespread use of cervical disc prosthesis can only be suggested when these questions have been answered by long term follow-up studies.

  7. SDSS-IV MaNGA: bulge-disc decomposition of IFU data cubes (BUDDI)

    Science.gov (United States)

    Johnston, Evelyn J.; Häußler, Boris; Aragón-Salamanca, Alfonso; Merrifield, Michael R.; Bamford, Steven; Bershady, Matthew A.; Bundy, Kevin; Drory, Niv; Fu, Hai; Law, David; Nitschelm, Christian; Thomas, Daniel; Roman Lopes, Alexandre; Wake, David; Yan, Renbin

    2017-02-01

    With the availability of large integral field unit (IFU) spectral surveys of nearby galaxies, there is now the potential to extract spectral information from across the bulges and discs of galaxies in a systematic way. This information can address questions such as how these components built up with time, how galaxies evolve and whether their evolution depends on other properties of the galaxy such as its mass or environment. We present bulge-disc decomposition of IFU data cubes (BUDDI), a new approach to fit the two-dimensional light profiles of galaxies as a function of wavelength to extract the spectral properties of these galaxies' discs and bulges. The fitting is carried out using GALFITM, a modified form of GALFIT which can fit multiwaveband images simultaneously. The benefit of this technique over traditional multiwaveband fits is that the stellar populations of each component can be constrained using knowledge over the whole image and spectrum available. The decomposition has been developed using commissioning data from the Sloan Digital Sky Survey-IV Mapping Nearby Galaxies at APO (MaNGA) survey with redshifts z 22 arcsec, but can be applied to any IFU data of a nearby galaxy with similar or better spatial resolution and coverage. We present an overview of the fitting process, the results from our tests, and we finish with example stellar population analyses of early-type galaxies from the MaNGA survey to give an indication of the scientific potential of applying bulge-disc decomposition to IFU data.

  8. DISC1 pathway in brain development: exploring therapeutic targets for major psychiatric disorders

    Directory of Open Access Journals (Sweden)

    Atsushi eKamiya

    2012-03-01

    Full Text Available Genetic risk factors for major psychiatric disorders play key roles in neurodevelopment. Thus, exploring the molecular pathways of risk genes is important not only for understanding the molecular mechanisms underlying brain development, but also to decipher how genetic disturbances affect brain maturation and functioning relevant to major mental illnesses. During the last decade, there has been significant progress in determining the mechanisms whereby risk genes impact brain development. Nonetheless, given that the majority of psychiatric disorders have etiological complexities encompassing multiple risk genes and environmental factors, the biological mechanisms of these diseases remain poorly understood. How can we move forward in our research for discovery of the biological markers and novel therapeutic targets for major mental disorders? Here we review recent progress in the neurobiology of Disrupted in schizophrenia 1 (DISC1, a major risk gene for major mental disorders, with a particular focus on its roles in cerebral cortex development. Convergent findings implicate DISC1 as part of a large, multi-step pathway implicated in various cellular processes and signal transduction. We discuss links between the DISC1 pathway and environmental factors, such as immune/inflammatory responses, which may suggest novel therapeutic targets. Existing treatments for major mental disorders are hampered by a limited number of pharmacological targets. Consequently, elucidation of the DISC1 pathway, and its association with neuropsychiatric disorders, may offer hope for novel treatment interventions.

  9. Radiative transfer calculations of the diffuse ionized gas in disc galaxies with cosmic ray feedback

    Science.gov (United States)

    Vandenbroucke, Bert; Wood, Kenneth; Girichidis, Philipp; Hill, Alex S.; Peters, Thomas

    2018-05-01

    The large vertical scale heights of the diffuse ionized gas (DIG) in disc galaxies are challenging to model, as hydrodynamical models including only thermal feedback seem to be unable to support gas at these heights. In this paper, we use a three-dimensional Monte Carlo radiation transfer code to post-process disc simulations of the Simulating the Life-Cycle of Molecular Clouds project that include feedback by cosmic rays. We show that the more extended discs in simulations including cosmic ray feedback naturally lead to larger scale heights for the DIG which are more in line with observed scale heights. We also show that including a fiducial cosmic ray heating term in our model can help to increase the temperature as a function of disc scale height, but fails to reproduce observed DIG nitrogen and sulphur forbidden line intensities. We show that, to reproduce these line emissions, we require a heating mechanism that affects gas over a larger density range than is achieved by cosmic ray heating, which can be achieved by fine tuning the total luminosity of ionizing sources to get an appropriate ionizing spectrum as a function of scale height. This result sheds a new light on the relation between forbidden line emissions and temperature profiles for realistic DIG gas distributions.

  10. Effect of genetic variation in a Drosophila model of diabetes-associated misfolded human proinsulin.

    Science.gov (United States)

    He, Bin Z; Ludwig, Michael Z; Dickerson, Desiree A; Barse, Levi; Arun, Bharath; Vilhjálmsson, Bjarni J; Jiang, Pengyao; Park, Soo-Young; Tamarina, Natalia A; Selleck, Scott B; Wittkopp, Patricia J; Bell, Graeme I; Kreitman, Martin

    2014-02-01

    The identification and validation of gene-gene interactions is a major challenge in human studies. Here, we explore an approach for studying epistasis in humans using a Drosophila melanogaster model of neonatal diabetes mellitus. Expression of the mutant preproinsulin (hINS(C96Y)) in the eye imaginal disc mimics the human disease: it activates conserved stress-response pathways and leads to cell death (reduction in eye area). Dominant-acting variants in wild-derived inbred lines from the Drosophila Genetics Reference Panel produce a continuous, highly heritable distribution of eye-degeneration phenotypes in a hINS(C96Y) background. A genome-wide association study (GWAS) in 154 sequenced lines identified a sharp peak on chromosome 3L, which mapped to a 400-bp linkage block within an intron of the gene sulfateless (sfl). RNAi knockdown of sfl enhanced the eye-degeneration phenotype in a mutant-hINS-dependent manner. RNAi against two additional genes in the heparan sulfate (HS) biosynthetic pathway (ttv and botv), in which sfl acts, also modified the eye phenotype in a hINS(C96Y)-dependent manner, strongly suggesting a novel link between HS-modified proteins and cellular responses to misfolded proteins. Finally, we evaluated allele-specific expression difference between the two major sfl-intronic haplotypes in heterozygtes. The results showed significant heterogeneity in marker-associated gene expression, thereby leaving the causal mutation(s) and its mechanism unidentified. In conclusion, the ability to create a model of human genetic disease, map a QTL by GWAS to a specific gene, and validate its contribution to disease with available genetic resources and the potential to experimentally link the variant to a molecular mechanism demonstrate the many advantages Drosophila holds in determining the genetic underpinnings of human disease.

  11. Strong dietary restrictions protect Drosophila against anoxia/reoxygenation injuries.

    Directory of Open Access Journals (Sweden)

    Paul Vigne

    Full Text Available Reoxygenation of ischemic tissues is a major factor that determines the severity of cardiovascular diseases. This paper describes the consequences of anoxia/reoxygenation (A/R stresses on Drosophila, a useful, anoxia tolerant, model organism.Newly emerged adult male flies were exposed to anoxic conditions (<1% O2 for 1 to 6 hours, reoxygenated and their survival was monitored.A/R stresses induced a transient increase in mortality which peaked at the time of reoxygenation. Then flies recovered low mortality rates similar to those of control flies. A/R induced mortality was strongly dependent on dietary conditions during the 48 h that preceded anoxia. Well fed flies were anoxia sensitive. Strong dietary restrictions and starvation conditions protected flies against A/R injuries. The tolerance to anoxia was associated to large decreases in glycogen, protein, and ATP contents. During anoxia, anoxia tolerant flies produced more lactate, less phosphate and they maintained more stable ATP levels than anoxia sensitive flies. Moderate dietary restrictions, which increased the longevity of normoxic flies, did not promote resistance to A/R stresses. Diet dependent A/R injuries were still observed in sigma loss of function mutants and they were insensitive to dietary rapamycin or resveratrol. AICAR (5-aminoimidazole-4-carboxamide-1-beta-D-ribose-furanoside, an activator AMP kinase decreased A/R injuries. Mutants in the insulin signalling pathway were more anoxia tolerant in a fed state.Long A/R stresses induce a transient increase in mortality in Drosophila. This mortality is highly dependent on dietary conditions prior to the stress. Strong dietary restrictions and starvation conditions protect flies against A/R injuries, probably by inducing a major remodelling of energy metabolism. The results also indicate that mechanistically different responses develop in response to dietary restrictions of different strengths. AMP kinase and the insulin signalling

  12. Cytochrome P450-Dependent Metabolism of Caffeine in Drosophila melanogaster

    Science.gov (United States)

    Coelho, Alexandra; Fraichard, Stephane; Le Goff, Gaëlle; Faure, Philippe; Artur, Yves; Ferveur, Jean-François; Heydel, Jean-Marie

    2015-01-01

    Caffeine (1, 3, 7-trimethylxanthine), an alkaloid produced by plants, has antioxidant and insecticide properties that can affect metabolism and cognition. In vertebrates, the metabolites derived from caffeine have been identified, and their functions have been characterized. However, the metabolites of caffeine in insects remain unknown. Thus, using radiolabelled caffeine, we have identified some of the primary caffeine metabolites produced in the body of Drosophila melanogaster males, including theobromine, paraxanthine and theophylline. In contrast to mammals, theobromine was the predominant metabolite (paraxanthine in humans; theophylline in monkeys; 1, 3, 7-trimethyluric acid in rodents). A transcriptomic screen of Drosophila flies exposed to caffeine revealed the coordinated variation of a large set of genes that encode xenobiotic-metabolizing proteins, including several cytochromes P450s (CYPs) that were highly overexpressed. Flies treated with metyrapone—an inhibitor of CYP enzymes—showed dramatically decreased caffeine metabolism, indicating that CYPs are involved in this process. Using interference RNA genetic silencing, we measured the metabolic and transcriptomic effect of three candidate CYPs. Silencing of CYP6d5 completely abolished theobromine synthesis, whereas CYP6a8 and CYP12d1 silencing induced different consequences on metabolism and gene expression. Therefore, we characterized several metabolic products and some enzymes potentially involved in the degradation of caffeine. In conclusion, this pioneer approach to caffeine metabolism in insects opens novel perspectives for the investigation of the physiological effects of caffeine metabolites. It also indicates that caffeine could be used as a biomarker to evaluate CYP phenotypes in Drosophila and other insects. PMID:25671424

  13. Cytochrome P450-dependent metabolism of caffeine in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Alexandra Coelho

    Full Text Available Caffeine (1, 3, 7-trimethylxanthine, an alkaloid produced by plants, has antioxidant and insecticide properties that can affect metabolism and cognition. In vertebrates, the metabolites derived from caffeine have been identified, and their functions have been characterized. However, the metabolites of caffeine in insects remain unknown. Thus, using radiolabelled caffeine, we have identified some of the primary caffeine metabolites produced in the body of Drosophila melanogaster males, including theobromine, paraxanthine and theophylline. In contrast to mammals, theobromine was the predominant metabolite (paraxanthine in humans; theophylline in monkeys; 1, 3, 7-trimethyluric acid in rodents. A transcriptomic screen of Drosophila flies exposed to caffeine revealed the coordinated variation of a large set of genes that encode xenobiotic-metabolizing proteins, including several cytochromes P450s (CYPs that were highly overexpressed. Flies treated with metyrapone--an inhibitor of CYP enzymes--showed dramatically decreased caffeine metabolism, indicating that CYPs are involved in this process. Using interference RNA genetic silencing, we measured the metabolic and transcriptomic effect of three candidate CYPs. Silencing of CYP6d5 completely abolished theobromine synthesis, whereas CYP6a8 and CYP12d1 silencing induced different consequences on metabolism and gene expression. Therefore, we characterized several metabolic products and some enzymes potentially involved in the degradation of caffeine. In conclusion, this pioneer approach to caffeine metabolism in insects opens novel perspectives for the investigation of the physiological effects of caffeine metabolites. It also indicates that caffeine could be used as a biomarker to evaluate CYP phenotypes in Drosophila and other insects.

  14. A computational study of intervertebral disc degeneration in relation to changes in regional tissue composition and disc nutrition

    OpenAIRE

    Ruiz Wills, Carlos

    2015-01-01

    Up to 85% of the world population suffers from low back pain, a clinical condition often related to the intervertebral disc (IVD) degeneration (DD). Altered disc cell nutrition affects cell viability and can generate catabolic cascades that degrade the extracellular matrix (ECM). Also, a major degenerative biochemical change in the disc is the proteoglycan (PG) loss, which affects the osmotic pressure and hydration that is critical for cell nutrition. However, the relationship between biochem...

  15. Gut-associated microbes of Drosophila melanogaster

    Science.gov (United States)

    Broderick, Nichole; Lemaitre, Bruno

    2012-01-01

    There is growing interest in using Drosophila melanogaster to elucidate mechanisms that underlie the complex relationships between a host and its microbiota. In addition to the many genetic resources and tools Drosophila provides, its associated microbiota is relatively simple (1–30 taxa), in contrast to the complex diversity associated with vertebrates (> 500 taxa). These attributes highlight the potential of this system to dissect the complex cellular and molecular interactions that occur between a host and its microbiota. In this review, we summarize what is known regarding the composition of gut-associated microbes of Drosophila and their impact on host physiology. We also discuss these interactions in the context of their natural history and ecology and describe some recent insights into mechanisms by which Drosophila and its gut microbiota interact. “Workers with Drosophila have been considered fortunate in that they deal with the first multicellular invertebrate to be cultured monoxenically (Delcourt and Guyenot, 1910); the first to be handled axenically on a semisynthetic diet (Guyenot, 1917); and the first to be grown on a defined diet (Schultz et al., 1946). This list of advantages is somewhat embarrassing, since it implies an interest in nutrition that, in reality, was only secondary. The very first studies were concerned with the reduction of variability in genetic experiments (Delcourt and Guyenot, 1910) and standardization of the nutritional environment.” -James Sang, 1959 Ann NY Acad 1 PMID:22572876

  16. Secular instabilities of Keplerian stellar discs

    Science.gov (United States)

    Kaur, Karamveer; Kazandjian, Mher V.; Sridhar, S.; Touma, Jihad R.

    2018-05-01

    We present idealized models of a razor-thin, axisymmetric, Keplerian stellar disc around a massive black hole, and study non-axisymmetric secular instabilities in the absence of either counter-rotation or loss cones. These discs are prograde mono-energetic waterbags, whose phase-space distribution functions are constant for orbits within a range of eccentricities (e) and zero outside this range. The linear normal modes of waterbags are composed of sinusoidal disturbances of the edges of distribution function in phase space. Waterbags that include circular orbits (polarcaps) have one stable linear normal mode for each azimuthal wavenumber m. The m = 1 mode always has positive pattern speed and, for polarcaps consisting of orbits with e normal modes for each m, which can be stable or unstable. We derive analytical expressions for the instability condition, pattern speeds, growth rates, and normal mode structure. Narrow bands are unstable to modes with a wide range in m. Numerical simulations confirm linear theory and follow the non-linear evolution of instabilities. Long-time integration suggests that instabilities of different m grow, interact non-linearly, and relax collisionlessly to a coarse-grained equilibrium with a wide range of eccentricities.

  17. The cellular memory disc of reprogrammed cells.

    Science.gov (United States)

    Anjamrooz, Seyed Hadi

    2013-04-01

    The crucial facts underlying the low efficiency of cellular reprogramming are poorly understood. Cellular reprogramming occurs in nuclear transfer, induced pluripotent stem cell (iPSC) formation, cell fusion, and lineage-switching experiments. Despite these advances, there are three fundamental problems to be addressed: (1) the majority of cells cannot be reprogrammed, (2) the efficiency of reprogramming cells is usually low, and (3) the reprogrammed cells developed from a patient's own cells activate immune responses. These shortcomings present major obstacles for using reprogramming approaches in customised cell therapy. In this Perspective, the author synthesises past and present observations in the field of cellular reprogramming to propose a theoretical picture of the cellular memory disc. The current hypothesis is that all cells undergo an endogenous and exogenous holographic memorisation such that parts of the cellular memory dramatically decrease the efficiency of reprogramming cells, act like a barrier against reprogramming in the majority of cells, and activate immune responses. Accordingly, the focus of this review is mainly to describe the cellular memory disc (CMD). Based on the present theory, cellular memory includes three parts: a reprogramming-resistance memory (RRM), a switch-promoting memory (SPM) and a culture-induced memory (CIM). The cellular memory arises genetically, epigenetically and non-genetically and affects cellular behaviours. [corrected].

  18. Vortex ring state by full-field actuator disc model

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, J.N.; Shen, W.Z.; Munduate, X. [DTU, Dept. of Energy Engineering, Lyngby (Denmark)

    1997-08-01

    One-dimensional momentum theory provides a simple analytical tool for analysing the gross flow behavior of lifting propellers and rotors. Combined with a blade-element strip-theory approach, it has for many years been the most popular model for load and performance predictions of wind turbines. The model works well at moderate and high wind velocities, but is not reliable at small wind velocities, where the expansion of the wake is large and the flow field behind the rotor dominated by turbulent mixing. This is normally referred to as the turbulent wake state or the vortex ring state. In the vortex ring state, momentum theory predicts a decrease of thrust whereas the opposite is found from experiments. The reason for the disagreement is that recirculation takes place behind the rotor with the consequence that the stream tubes past the rotor becomes effectively chocked. This represents a condition at which streamlines no longer carry fluid elements from far upstream to far downstream, hence one-dimensional momentum theory is invalid and empirical corrections have to be introduced. More sophisticated analytical or semi-analytical rotor models have been used to describe stationary flow fields for heavily loaded propellers. In recent years generalized actuator disc models have been developed, but up to now no detailed computations of the turbulent wake state or the vortex ring state have been performed. In the present work the phenomenon is simulated by direct simulation of the Navier-Stokes equations, where the influence of the rotor on the flow field is modelled simply by replacing the blades by an actuator disc with a constant normal load. (EG) 13 refs.

  19. Auto fluorescence of intervertebral disc tissue: a new diagnostic tool.

    Science.gov (United States)

    Hoell, T; Huschak, G; Beier, A; Hüttmann, G; Minkus, Y; Holzhausen, H J; Meisel, H J

    2006-08-01

    The paper reports on auto fluorescence phenomena of inter-vertebral human discs. It systematically investigates the auto fluorescence effects of ex vivo disc specimen and reports on surgical cases to demonstrate the potential value of the new method. The paper offers biologic explanations of the phenomenon and discusses the potential value of the UV auto fluorescence technique as a diagnostic tool. Intra- and postoperative observations are made by a surgical microscope with an integrated UV light source. Quantitative measurements were carried out using a photon counter and a spectrometer ex vivo. The auto fluorescence phenomenon allows the differentiation of traumatized and degenerated disc tissue intraoperatively in some cases, it allows the differentiation of bony and collagen endplate in cervical disc surgery. The source of the auto fluorescent light emission are amino acids of the collagen molecules. The proteoglycan components and the liquid components of the disc do not show relevant auto fluorescence. Emission wavelength of disc material is equivalent to color perception. It differs due to different collagen composition of the intervertebral disc components from yellow-green to blue-green and can be visualized in situ by naked eye.UV-auto fluorescence of inter-vertebral discs is a new clinical tool that has the potential to differentiate disc material from the anatomical surrounding, to distinguish between different fractions of the disc and to give information on the quality and status of the disc material. Since the technology has just emerged, it needs further investigations to quantify the clinical observations reported in this paper.

  20. Disc-halo interactions in ΛCDM

    Science.gov (United States)

    Bauer, Jacob S.; Widrow, Lawrence M.; Erkal, Denis

    2018-05-01

    We present a new method for embedding a stellar disc in a cosmological dark matter halo and provide a worked example from a Λ cold dark matter zoom-in simulation. The disc is inserted into the halo at a redshift z = 3 as a zero-mass rigid body. Its mass and size are then increased adiabatically while its position, velocity, and orientation are determined from rigid-body dynamics. At z = 1, the rigid disc (RD) is replaced by an N-body disc whose particles sample a three-integral distribution function (DF). The simulation then proceeds to z = 0 with live disc (LD) and halo particles. By comparison, other methods assume one or more of the following: the centre of the RD during the growth phase is pinned to the minimum of the halo potential, the orientation of the RD is fixed, or the live N-body disc is constructed from a two rather than three-integral DF. In general, the presence of a disc makes the halo rounder, more centrally concentrated, and smoother, especially in the innermost regions. We find that methods in which the disc is pinned to the minimum of the halo potential tend to overestimate the amount of adiabatic contraction. Additionally, the effect of the disc on the subhalo distribution appears to be rather insensitive to the disc insertion method. The LD in our simulation develops a bar that is consistent with the bars seen in late-type spiral galaxies. In addition, particles from the disc are launched or `kicked up' to high galactic latitudes.

  1. Retinal Nerve Fiber Layer Protrusion Associated with Tilted Optic Discs.

    Science.gov (United States)

    Chiang, Jaclyn; Yapp, Michael; Ly, Angelica; Hennessy, Michael P; Kalloniatis, Michael; Zangerl, Barbara

    2018-03-01

    This study resulted in the identification of an optic nerve head (ONH) feature associated with tilted optic discs, which might potentially contribute to ONH pathologies. Knowledge of such findings will enhance clinical insights and drive future opportunities to understand disease processes related to tilted optic discs. The aim of this study was to identify novel retinal nerve fiber layer (RNFL) anomalies by evaluating tilted optic discs using optical coherence tomography. An observed retinal nerve fiber protrusion was further investigated for association with other morphological or functional parameters. A retrospective review of 400 randomly selected adult patients with ONH examinations was conducted in a referral-only, diagnostic imaging center. After excluding other ONH pathologies, 215 patients were enrolled and evaluated for optic disc tilt and/or torsion. Gross anatomical ONH features, including size and rim or parapapillary region elevation, were assessed with stereoscopic fundus photography. Optical coherence tomography provided detailed morphological information of individual retinal layers. Statistical analysis was applied to identify significant changes between individual patient cohorts. A dome-shaped hyperreflective RNFL bulge, protruding into the neurosensory retina at the optic disc margins, was identified in 17 eyes with tilted optic discs. Available follow-up data were inconclusive regarding natural changes with this ONH feature. This RNFL herniation was significantly correlated with smaller than average optic disc size (P = .005), congenital disc tilt (P optic discs, which has not previously been assessed as an independent ONH structure. The feature is predominantly related to congenital crowded, small optic discs and variable between patients. This study is an important first step to elucidate diagnostic capabilities of tilted disc morphological changes and understanding associated functional deficits.

  2. Calibrated Tully-Fisher relations for improved estimates of disc rotation velocities

    Science.gov (United States)

    Reyes, R.; Mandelbaum, R.; Gunn, J. E.; Pizagno, J.; Lackner, C. N.

    2011-11-01

    In this paper, we derive scaling relations between photometric observable quantities and disc galaxy rotation velocity Vrot or Tully-Fisher relations (TFRs). Our methodology is dictated by our purpose of obtaining purely photometric, minimal-scatter estimators of Vrot applicable to large galaxy samples from imaging surveys. To achieve this goal, we have constructed a sample of 189 disc galaxies at redshifts z < 0.1 with long-slit Hα spectroscopy from Pizagno et al. and new observations. By construction, this sample is a fair subsample of a large, well-defined parent disc sample of ˜170 000 galaxies selected from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). The optimal photometric estimator of Vrot we find is stellar mass M★ from Bell et al., based on the linear combination of a luminosity and a colour. Assuming a Kroupa initial mass function (IMF), we find: log [V80/(km s-1)] = (2.142 ± 0.004) + (0.278 ± 0.010)[log (M★/M⊙) - 10.10], where V80 is the rotation velocity measured at the radius R80 containing 80 per cent of the i-band galaxy light. This relation has an intrinsic Gaussian scatter ? dex and a measured scatter σmeas= 0.056 dex in log V80. For a fixed IMF, we find that the dynamical-to-stellar mass ratios within R80, (Mdyn/M★)(R80), decrease from approximately 10 to 3, as stellar mass increases from M★≈ 109 to 1011 M⊙. At a fixed stellar mass, (Mdyn/M★)(R80) increases with disc size, so that it correlates more tightly with stellar surface density than with stellar mass or disc size alone. We interpret the observed variation in (Mdyn/M★)(R80) with disc size as a reflection of the fact that disc size dictates the radius at which Mdyn/M★ is measured, and consequently, the fraction of the dark matter 'seen' by the gas at that radius. For the lowest M★ galaxies, we find a positive correlation between TFR residuals and disc sizes, indicating that the total density profile is dominated by dark matter on these scales. For the

  3. Drosophila MOF regulates DIAP1 and induces apoptosis in a JNK dependent pathway.

    Science.gov (United States)

    Pushpavalli, Sreerangam N C V L; Sarkar, Arpita; Ramaiah, M Janaki; Koteswara Rao, G; Bag, Indira; Bhadra, Utpal; Pal-Bhadra, Manika

    2016-03-01

    Histone modulations have been implicated in various cellular and developmental processes where in Drosophila Mof is involved in acetylation of H4K16. Reduction in the size of larval imaginal discs is observed in the null mutants of mof with increased apoptosis. Deficiency involving Hid, Reaper and Grim [H99] alleviated mof (RNAi) induced apoptosis in the eye discs. mof (RNAi) induced apoptosis leads to activation of caspases which is suppressed by over expression of caspase inhibitors like P35 and Diap1 clearly depicting the role of caspases in programmed cell death. Also apoptosis induced by knockdown of mof is rescued by JNK mutants of bsk and tak1 indicating the role of JNK in mof (RNAi) induced apoptosis. The adult eye ablation phenotype produced by ectopic expression of Hid, Rpr and Grim, was restored by over expression of Mof. Accumulation of Mof at the Diap1 promoter 800 bp upstream of the transcription start site in wild type larvae is significantly higher (up to twofolds) compared to mof (1) mutants. This enrichment coincides with modification of histone H4K16Ac indicating an induction of direct transcriptional up regulation of Diap1 by Mof. Based on these results we propose that apoptosis triggered by mof (RNAi) proceeds through a caspase-dependent and JNK mediated pathway.

  4. Drosophila Big bang regulates the apical cytocortex and wing growth through junctional tension.

    Science.gov (United States)

    Tsoumpekos, Giorgos; Nemetschke, Linda; Knust, Elisabeth

    2018-03-05

    Growth of epithelial tissues is regulated by a plethora of components, including signaling and scaffolding proteins, but also by junctional tension, mediated by the actomyosin cytoskeleton. However, how these players are spatially organized and functionally coordinated is not well understood. Here, we identify the Drosophila melanogaster scaffolding protein Big bang as a novel regulator of growth in epithelial cells of the wing disc by ensuring proper junctional tension. Loss of big bang results in the reduction of the regulatory light chain of nonmuscle myosin, Spaghetti squash. This is associated with an increased apical cell surface, decreased junctional tension, and smaller wings. Strikingly, these phenotypic traits of big bang mutant discs can be rescued by expressing constitutively active Spaghetti squash. Big bang colocalizes with Spaghetti squash in the apical cytocortex and is found in the same protein complex. These results suggest that in epithelial cells of developing wings, the scaffolding protein Big bang controls apical cytocortex organization, which is important for regulating cell shape and tissue growth. © 2018 Tsoumpekos et al.

  5. Viruses and Antiviral Immunity in Drosophila

    Science.gov (United States)

    Xu, Jie; Cherry, Sara

    2013-01-01

    Viral pathogens present many challenges to organisms, driving the evolution of a myriad of antiviral strategies to combat infections. A wide variety of viruses infect invertebrates, including both natural pathogens that are insect-restricted, and viruses that are transmitted to vertebrates. Studies using the powerful tools available in the model organism Drosophila have expanded our understanding of antiviral defenses against diverse viruses. In this review, we will cover three major areas. First, we will describe the tools used to study viruses in Drosophila. Second, we will survey the major viruses that have been studied in Drosophila. And lastly, we will discuss the well-characterized mechanisms that are active against these diverse pathogens, focusing on non-RNAi mediated antiviral mechanisms. Antiviral RNAi is discussed in another paper in this issue. PMID:23680639

  6. Receptor Tyrosine Kinases in Drosophila Development

    Science.gov (United States)

    Sopko, Richelle; Perrimon, Norbert

    2013-01-01

    Tyrosine phosphorylation plays a significant role in a wide range of cellular processes. The Drosophila genome encodes more than 20 receptor tyrosine kinases and extensive studies in the past 20 years have illustrated their diverse roles and complex signaling mechanisms. Although some receptor tyrosine kinases have highly specific functions, others strikingly are used in rather ubiquitous manners. Receptor tyrosine kinases regulate a broad expanse of processes, ranging from cell survival and proliferation to differentiation and patterning. Remarkably, different receptor tyrosine kinases share many of the same effectors and their hierarchical organization is retained in disparate biological contexts. In this comprehensive review, we summarize what is known regarding each receptor tyrosine kinase during Drosophila development. Astonishingly, very little is known for approximately half of all Drosophila receptor tyrosine kinases. PMID:23732470

  7. Apoptosis in Drosophila: which role for mitochondria?

    Science.gov (United States)

    Clavier, Amandine; Rincheval-Arnold, Aurore; Colin, Jessie; Mignotte, Bernard; Guénal, Isabelle

    2016-03-01

    It is now well established that the mitochondrion is a central regulator of mammalian cell apoptosis. However, the importance of this organelle in non-mammalian apoptosis has long been regarded as minor, mainly because of the absence of a crucial role for cytochrome c in caspase activation. Recent results indicate that the control of caspase activation and cell death in Drosophila occurs at the mitochondrial level. Numerous proteins, including RHG proteins and proteins of the Bcl-2 family that are key regulators of Drosophila apoptosis, constitutively or transiently localize in mitochondria. These proteins participate in the cell death process at different levels such as degradation of Diap1, a Drosophila IAP, production of mitochondrial reactive oxygen species or stimulation of the mitochondrial fission machinery. Here, we review these mitochondrial events that might have their counterpart in human.

  8. The phase diagram of scalar field theory on the fuzzy disc

    Energy Technology Data Exchange (ETDEWEB)

    Rea, Simone; Sämann, Christian [Maxwell Institute for Mathematical Sciences, Department of Mathematics,Heriot-Watt University,Colin Maclaurin Building, Riccarton, Edinburgh EH14 4AS (United Kingdom)

    2015-11-17

    Using a recently developed bootstrapping method, we compute the phase diagram of scalar field theory on the fuzzy disc with quartic even potential. We find three distinct phases with second and third order phase transitions between them. In particular, we find that the second order phase transition happens approximately at a fixed ratio of the two coupling constants defining the potential. We compute this ratio analytically in the limit of large coupling constants. Our results qualitatively agree with previously obtained numerical results.

  9. The transcriptional diversity of 25 Drosophila cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Cherbas, Lucy [Indiana Univ., Bloomington, IN (United States); Willingham, Aarron [Affymetrix Inc., Santa Clara, CA (United States); Zhang, Dayu [Indiana Univ., Bloomington, IN (United States); Yang, Li [University of Connecticut Health Center, Farmington, Connecticut (United States); Zou, Yi [Indiana Univ., Bloomington, IN (United States); Eads, Brian D. [Indiana Univ., Bloomington, IN (United States); Carlson, Joseph W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Landolin, Jane M. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kapranov, Philipp [Affymetrix Inc., Santa Clara, CA (United States); Dumais, Jacqueline [Affymetrix Inc., Santa Clara, CA (United States); Samsonova, Anastasia [Harvard Medical School, Boston, MA (United States); Choi, Jeong-Hyeon [Indiana Univ., Bloomington, IN (United States); Roberts, Johnny [Indiana Univ., Bloomington, IN (United States); Davis, Carrie A. [Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Tang, Haixu [Indiana Univ., Bloomington, IN (United States); van Baren, Marijke J. [Washington Univ., St. Louis, MO (United States); Ghosh, Srinka [Affymetrix Inc., Santa Clara, CA (United States); Dobin, Alexander [Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Bell, Kim [Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Lin, Wei [Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Langton, Laura [Washington Univ., St. Louis, MO (United States); Duff, Michael O. [University of Connecticut Health Center, Farmington, Connecticut (United States); Tenney, Aaron E. [Washington Univ., St. Louis, MO (United States); Zaleski, Chris [Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Brent, Michael R. [Washington Univ., St. Louis, MO (United States); Hoskins, Roger A. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kaufman, Thomas C. [Indiana University, Bloomington, Indiana (United States); Andrews, Justen [Indiana University, Bloomington, Indiana (United States); Graveley, Brenton R. [University of Connecticut Health Center, Farmington, Connecticut (United States); Perrimon, Norbert [Harvard Medical School, Boston, MA (United States); Howard Hughes Medical Institute, Boston, MA (United States); Celniker, Susan E. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Gingeras, Thomas R. [Affymetrix Inc., Santa Clara, CA (United States); Cold Spring Harbor Laboratory, Cold Spring Harbor, New York (United States); Cherbas, Peter [Indiana Univ., Bloomington, IN (United States)

    2010-12-22

    Drosophila melanogaster cell lines are important resources for cell biologists. In this article, we catalog the expression of exons, genes, and unannotated transcriptional signals for 25 lines. Unannotated transcription is substantial (typically 19% of euchromatic signal). Conservatively, we identify 1405 novel transcribed regions; 684 of these appear to be new exons of neighboring, often distant, genes. Sixty-four percent of genes are expressed detectably in at least one line, but only 21% are detected in all lines. Each cell line expresses, on average, 5885 genes, including a common set of 3109. Expression levels vary over several orders of magnitude. Major signaling pathways are well represented: most differentiation pathways are ‘‘off’’ and survival/growth pathways ‘‘on.’’ Roughly 50% of the genes expressed by each line are not part of the common set, and these show considerable individuality. Thirty-one percent are expressed at a higher level in at least one cell line than in any single developmental stage, suggesting that each line is enriched for genes characteristic of small sets of cells. Most remarkable is that imaginal disc-derived lines can generally be assigned, on the basis of expression, to small territories within developing discs. These mappings reveal unexpected stability of even fine-grained spatial determination. No two cell lines show identical transcription factor expression. We conclude that each line has retained features of an individual founder cell superimposed on a common ‘‘cell line‘‘ gene expression pattern. We report the transcriptional profiles of 25 Drosophila melanogaster cell lines, principally by whole-genome tiling microarray analysis of total RNA, carried out as part of the modENCODE project. The data produced in this study add to our knowledge of the cell lines and of the Drosophila transcriptome in several ways. We summarize the expression of previously annotated genes in each of the 25

  10. Thermophoretic aggregation of particles in a protoplanetary disc

    Science.gov (United States)

    Smith, Francis J.

    2018-04-01

    Thermophoresis causes particles to move down a temperature gradient to a cooler region of a neutral gas. An example is the temperature gradient in the gas around a large cold object, such as an aggregate of particles, cooled by radiation in a protoplanetary disc. Particles near this aggregate move down the temperature gradient to the aggregate, equivalent to the particles being attracted to it by an inter-particle thermophoretic force. This force is proportional to the temperature difference between gas and aggregate, to the gas density and to the cross-section of the aggregate. The force can be large. For example, calculations based on the equations of motion of the interacting particles show that it can be large enough in an optically thin environment to increase the rate of aggregation by up to six orders of magnitude when an aggregate radius lies between 0.1 μm and 1 mm. From 1 mm to about 10 cm aggregates drift inwards through the gas too quickly for the thermophoretic attraction to increase aggregation significantly; so they grow slowly, causing an observed accumulation of particles at these sizes. Particles above 10 cm move more quickly, causing aggregation due to collisions, but also causing fragmentation. However, calculations show that fragmenting particles and bouncing particles in inelastic collisions often have low enough relative velocities that thermophoresis brings them together again. This allows particles to grow above 1 m, which is otherwise difficult to explain.

  11. Different modes of APC/C activation control growth and neuron-glia interaction in the developing Drosophila eye.

    Science.gov (United States)

    Neuert, Helen; Yuva-Aydemir, Yeliz; Silies, Marion; Klämbt, Christian

    2017-12-15

    The development of the nervous system requires tight control of cell division, fate specification and migration. The anaphase-promoting complex/cyclosome (APC/C) is an E3 ubiquitin ligase that affects different steps of cell cycle progression, as well as having postmitotic functions in nervous system development. It can therefore link different developmental stages in one tissue. The two adaptor proteins, Fizzy/Cdc20 and Fizzy-related/Cdh1, confer APC/C substrate specificity. Here, we show that two distinct modes of APC/C function act during Drosophila eye development. Fizzy/Cdc20 controls the early growth of the eye disc anlage and the concomitant entry of glial cells onto the disc. In contrast, fzr/cdh1 acts during neuronal patterning and photoreceptor axon growth, and subsequently affects neuron-glia interaction. To further address the postmitotic role of Fzr/Cdh1 in controlling neuron-glia interaction, we identified a series of novel APC/C candidate substrates. Four of our candidate genes are required for fzr/cdh1 -dependent neuron-glia interaction, including the dynein light chain Dlc90F Taken together, our data show how different modes of APC/C activation can couple early growth and neuron-glia interaction during eye disc development. © 2017. Published by The Company of Biologists Ltd.

  12. Gas dynamics in tidal dwarf galaxies: Disc formation at z = 0

    Science.gov (United States)

    Lelli, Federico; Duc, Pierre-Alain; Brinks, Elias; Bournaud, Frédéric; McGaugh, Stacy S.; Lisenfeld, Ute; Weilbacher, Peter M.; Boquien, Médéric; Revaz, Yves; Braine, Jonathan; Koribalski, Bärbel S.; Belles, Pierre-Emmanuel

    2015-12-01

    Tidal dwarf galaxies (TDGs) are recycled objects that form within the collisional debris of interacting and merging galaxies. They are expected to be devoid of non-baryonic dark matter, since they can only form from dissipative material ejected from the discs of the progenitor galaxies. We investigate the gas dynamics in a sample of six bona fide TDGs around three interacting and post-interacting systems: NGC 4694, NGC 5291, and NGC 7252 ("Atoms for Peace"). For NGC 4694 and NGC 5291, we analyse existing H I data from the Very Large Array (VLA), while for NGC 7252 we present new H I observations from the Jansky VLA, together with long-slit and integral-field optical spectroscopy. For all six TDGs, the H I emission can be described by rotating disc models. These H I discs, however, have undergone less than a full rotation since the time of the interaction/merger event, raising the question of whether they are in dynamical equilibrium. Assuming that these discs are in equilibrium, the inferred dynamical masses are consistent with the observed baryonic masses, implying that TDGs are devoid of dark matter. This puts constraints on putative "dark discs" (either baryonic or non-baryonic) in the progenitor galaxies. Moreover, TDGs seem to systematically deviate from the baryonic Tully-Fisher relation. These results provide a challenging test for alternative theories like MOND. Based on observations made with ESO telescopes at Paranal Observatory under programmes 65.O-0563, 67.B-0049, and 083.B-0647.Appendices are available in electronic form at http://www.aanda.orgThe reduced data cubes are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A113

  13. The comparative effect of FUV, EUV and X-ray disc photoevaporation on gas giant separations

    Science.gov (United States)

    Jennings, Jeff; Ercolano, Barbara; Rosotti, Giovanni P.

    2018-04-01

    Gas giants' early (≲ 5 Myr) orbital evolution occurs in a disc losing mass in part to photoevaporation driven by high energy irradiance from the host star. This process may ultimately overcome viscous accretion to disperse the disc and halt migrating giants by starving their orbits of gas, imprinting on giant planet separations in evolved systems. Inversion of this distribution could then give insight into whether stellar FUV, EUV or X-ray flux dominates photoevaporation, constraining planet formation and disc evolution models. We use a 1D hydrodynamic code in population syntheses for gas giants undergoing Type II migration in a viscously evolving disc subject to either a primarily FUV, EUV or X-ray flux from a pre-solar T Tauri star. The photoevaporative mass loss profile's unique peak location and width in each energetic regime produces characteristic features in the distribution of giant separations: a severe dearth of ≲ 2 MJ planets interior to 5 AU in the FUV scenario, a sharp concentration of ≲ 3 MJ planets between ≈1.5 - 2 AU in the EUV case, and a relative abundance of ≈2 - 3.5 MJ giants interior to 0.5 AU in the X-ray model. These features do not resemble the observational sample of gas giants with mass constraints, though our results do show some weaker qualitative similarities. We thus assess how the differing photoevaporative profiles interact with migrating giants and address the effects of large model uncertainties as a step to better connect disc models with trends in the exoplanet population.

  14. Joint optic disc and cup boundary extraction from monocular fundus images.

    Science.gov (United States)

    Chakravarty, Arunava; Sivaswamy, Jayanthi

    2017-08-01

    Accurate segmentation of optic disc and cup from monocular color fundus images plays a significant role in the screening and diagnosis of glaucoma. Though optic cup is characterized by the drop in depth from the disc boundary, most existing methods segment the two structures separately and rely only on color and vessel kink based cues due to the lack of explicit depth information in color fundus images. We propose a novel boundary-based Conditional Random Field formulation that extracts both the optic disc and cup boundaries in a single optimization step. In addition to the color gradients, the proposed method explicitly models the depth which is estimated from the fundus image itself using a coupled, sparse dictionary trained on a set of image-depth map (derived from Optical Coherence Tomography) pairs. The estimated depth achieved a correlation coefficient of 0.80 with respect to the ground truth. The proposed segmentation method outperformed several state-of-the-art methods on five public datasets. The average dice coefficient was in the range of 0.87-0.97 for disc segmentation across three datasets and 0.83 for cup segmentation on the DRISHTI-GS1 test set. The method achieved a good glaucoma classification performance with an average AUC of 0.85 for five fold cross-validation on RIM-ONE v2. We propose a method to jointly segment the optic disc and cup boundaries by modeling the drop in depth between the two structures. Since our method requires a single fundus image per eye during testing it can be employed in the large-scale screening of glaucoma where expensive 3D imaging is unavailable. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. The dynamical fate of self-gravitating disc fragments after tidal downsizing

    Science.gov (United States)

    Forgan, Duncan; Parker, Richard J.; Rice, Ken

    2015-02-01

    The gravitational instability model of planet/brown dwarf formation proposes that protostellar discs can fragment into objects with masses above a few Jupiter masses at large semimajor axis. Tidal downsizing may reduce both the object mass and semimajor axis. However, most studies of tidal downsizing end when the protostellar disc disperses, while the system is embedded in its parent star-forming region. To compare disc fragment descendants with exoplanet and brown dwarf observations, the subsequent dynamical evolution must be explored. We carry out N-body integrations of fragment-fragment scattering in multi-object star systems, and star systems embedded in substructured clusters. In both cases, we use initial conditions generated by population synthesis models of tidal downsizing. The scattering simulations produce a wide range of eccentricities. The ejection rate is around 25 per cent. The ejecta mass distribution is similar to that for all objects, with a velocity dispersion consistent with those produced by full hydrodynamic simulations. The semimajor axis distribution after scattering extends to parsec scales. In the cluster simulations, 13 per cent of the objects are ejected from their planetary system, and around 10 per cent experience significant orbit modification. A small number of objects are recaptured on high-eccentricity, high-inclination orbits. The velocity distribution of ejecta is similar to that produced by fragment-fragment scattering. If fragment-fragment scattering and cluster stripping act together, then disc fragmentation should be efficient at producing free-floating substellar objects, and hence characterizing the free-floating planet population will provide strong constraints on the frequency of disc fragmentation.

  16. Drosophila olfactory receptors as classifiers for volatiles from disparate real world applications

    International Nuclear Information System (INIS)

    Nowotny, Thomas; De Bruyne, Marien; Warr, Coral G; Berna, Amalia Z; Trowell, Stephen C

    2014-01-01

    Olfactory receptors evolved to provide animals with ecologically and behaviourally relevant information. The resulting extreme sensitivity and discrimination has proven useful to humans, who have therefore co-opted some animals’ sense of smell. One aim of machine olfaction research is to replace the use of animal noses and one avenue of such research aims to incorporate olfactory receptors into artificial noses. Here, we investigate how well the olfactory receptors of the fruit fly, Drosophila melanogaster, perform in classifying volatile odourants that they would not normally encounter. We collected a large number of in vivo recordings from individual Drosophila olfactory receptor neurons in response to an ecologically relevant set of 36 chemicals related to wine (‘wine set’) and an ecologically irrelevant set of 35 chemicals related to chemical hazards (‘industrial set’), each chemical at a single concentration. Resampled response sets were used to classify the chemicals against all others within each set, using a standard linear support vector machine classifier and a wrapper approach. Drosophila receptors appear highly capable of distinguishing chemicals that they have not evolved to process. In contrast to previous work with metal oxide sensors, Drosophila receptors achieved the best recognition accuracy if the outputs of all 20 receptor types were used. (paper)

  17. SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

    Science.gov (United States)

    Yan, Rihui; Thomas, Sharon E; Tsai, Jui-He; Yamada, Yukihiro; McKee, Bruce D

    2010-02-08

    Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

  18. Targeted Lipidomics in Drosophila melanogaster Identifies Novel 2-Monoacylglycerols and N-acyl Amides

    Science.gov (United States)

    Takacs, Sara M.; Stuart, Jordyn M.; Basnet, Arjun; Raboune, Siham; Widlanski, Theodore S.; Doherty, Patrick; Bradshaw, Heather B.

    2013-01-01

    Lipid metabolism is critical to coordinate organ development and physiology in response to tissue-autonomous signals and environmental cues. Changes to the availability and signaling of lipid mediators can limit competitiveness, adaptation to environmental stressors, and augment pathological processes. Two classes of lipids, the N-acyl amides and the 2-acyl glycerols, have emerged as important signaling molecules in a wide range of species with important signaling properties, though most of what is known about their cellular functions is from mammalian models. Therefore, expanding available knowledge on the repertoire of these lipids in invertebrates will provide additional avenues of research aimed at elucidating biosynthetic, metabolic, and signaling properties of these molecules. Drosophila melanogaster is a commonly used organism to study intercellular communication, including the functions of bioactive lipids. However, limited information is available on the molecular identity of lipids with putative biological activities in Drosophila. Here, we used a targeted lipidomics approach to identify putative signaling lipids in third instar Drosophila larvae, possessing particularly large lipid mass in their fat body. We identified 2-linoleoyl glycerol, 2-oleoyl glycerol, and 45 N-acyl amides in larval tissues, and validated our findings by the comparative analysis of Oregon-RS, Canton-S and w1118 strains. Data here suggest that Drosophila represent another model system to use for the study of 2-acyl glycerol and N-acyl amide signaling. PMID:23874457

  19. Drosophila melanogaster Models of Metal-Related Human Diseases and Metal Toxicity.

    Science.gov (United States)

    Calap-Quintana, Pablo; González-Fernández, Javier; Sebastiá-Ortega, Noelia; Llorens, José Vicente; Moltó, María Dolores

    2017-07-06

    Iron, copper and zinc are transition metals essential for life because they are required in a multitude of biological processes. Organisms have evolved to acquire metals from nutrition and to maintain adequate levels of each metal to avoid damaging effects associated with its deficiency, excess or misplacement. Interestingly, the main components of metal homeostatic pathways are conserved, with many orthologues of the human metal-related genes having been identified and characterized in Drosophila melanogaster . Drosophila has gained appreciation as a useful model for studying human diseases, including those caused by mutations in pathways controlling cellular metal homeostasis. Flies have many advantages in the laboratory, such as a short life cycle, easy handling and inexpensive maintenance. Furthermore, they can be raised in a large number. In addition, flies are greatly appreciated because they offer a considerable number of genetic tools to address some of the unresolved questions concerning disease pathology, which in turn could contribute to our understanding of the metal metabolism and homeostasis. This review recapitulates the metabolism of the principal transition metals, namely iron, zinc and copper, in Drosophila and the utility of this organism as an experimental model to explore the role of metal dyshomeostasis in different human diseases. Finally, a summary of the contribution of Drosophila as a model for testing metal toxicity is provided.

  20. A Test for Gene Flow among Sympatric and Allopatric Hawaiian Picture-Winged Drosophila.

    Science.gov (United States)

    Kang, Lin; Garner, Harold R; Price, Donald K; Michalak, Pawel

    2017-06-01

    The Hawaiian Drosophila are one of the most species-rich endemic groups in Hawaii and a spectacular example of adaptive radiation. Drosophila silvestris and D. heteroneura are two closely related picture-winged Drosophila species that occur sympatrically on Hawaii Island and are known to hybridize in nature, yet exhibit highly divergent behavioral and morphological traits driven largely through sexual selection. Their closest-related allopatric species, D. planitibia from Maui, exhibits hybrid male sterility and reduced behavioral reproductive isolation when crossed experimentally with D. silvestris or D. heteroneura. A modified four-taxon test for gene flow was applied to recently obtained genomes of the three Hawaiian Drosophila species. The analysis indicates recent gene flow in sympatry, but also, although less extensive, between allopatric species. This study underscores the prevalence of gene flow, even in taxonomic groups considered classic examples of allopatric speciation on islands. The potential confounding effects of gene flow in phylogenetic and population genetics inference are discussed, as well as the implications for conservation.

  1. Microwave effects in Drosophila melanogaster

    International Nuclear Information System (INIS)

    Dardalhon, M.; Averbeck, D.; Berteaud, A.J.

    1979-01-01

    Experiments were set up to investigate the effects of open space microwave irradiation of the millimeter (73 GHz) and the centimeter (17 GHz) range in Drosophila melanogaster. We used the wild type strain Paris and the strain delta carrying melanitic tumors in the 3rd larval stage, in the pupae and the adults. The power densities were up to 100mW.cm -2 for 73 GHz and about 60 mW.cm -2 for microwaves at 17 GHz. After 2h exposure to microwaves of 17 GHz or 73 GHz the hatching of the irradiated eggs and their development were normal. In a few cases there was a tendency towards a diminution of the survival of eggs treated at different stages, of larvae treated in the stages 1, 2 and 3 and of treated pupae. However, this was not always statistically significant. The microwave treatment did not induce teratological changes in the adults. A statistical analysis brought about slight diminutions in the incidence and multiplicity of tumors in adult flies. When wild type females were exposed to microwaves of 17 GHz for 16 or 21 h and crossed with untreated males we observed a marked increase in fertility as compared to untreated samples. The viability and tumor incidence in the offspring was not affected. Similar results were obtained when microwaves treated males were crossed with untreated females

  2. Olfactory memory traces in Drosophila.

    Science.gov (United States)

    Berry, Jacob; Krause, William C; Davis, Ronald L

    2008-01-01

    In Drosophila, the fruit fly, coincident exposure to an odor and an aversive electric shock can produce robust behavioral memory. This behavioral memory is thought to be regulated by cellular memory traces within the central nervous system of the fly. These molecular, physiological, or structural changes in neurons, induced by pairing odor and shock, regulate behavior by altering the neurons' response to the learned environment. Recently, novel in vivo functional imaging techniques have allowed researchers to observe cellular memory traces in intact animals. These investigations have revealed interesting temporal and spatial dynamics of cellular memory traces. First, a short-term cellular memory trace was discovered that exists in the antennal lobe, an early site of olfactory processing. This trace represents the recruitment of new synaptic activity into the odor representation and forms for only a short period of time just after training. Second, an intermediate-term cellular memory trace was found in the dorsal paired medial neuron, a neuron thought to play a role in stabilizing olfactory memories. Finally, a long-term protein synthesis-dependent cellular memory trace was discovered in the mushroom bodies, a structure long implicated in olfactory learning and memory. Therefore, it appears that aversive olfactory associations are encoded by multiple cellular memory traces that occur in different regions of the brain with different temporal domains.

  3. The reports of thick discs' deaths are greatly exaggerated. Thick discs are NOT artefacts caused by diffuse scattered light

    Science.gov (United States)

    Comerón, S.; Salo, H.; Knapen, J. H.

    2018-02-01

    Recent studies have made the community aware of the importance of accounting for scattered light when examining low-surface-brightness galaxy features such as thick discs. In our past studies of the thick discs of edge-on galaxies in the Spitzer Survey of Stellar Structure in Galaxies - the S4G - we modelled the point spread function as a Gaussian. In this paper we re-examine our results using a revised point spread function model that accounts for extended wings out to more than 2\\farcm5. We study the 3.6 μm images of 141 edge-on galaxies from the S4G and its early-type galaxy extension. Thus, we more than double the samples examined in our past studies. We decompose the surface-brightness profiles of the galaxies perpendicular to their mid-planes assuming that discs are made of two stellar discs in hydrostatic equilibrium. We decompose the axial surface-brightness profiles of galaxies to model the central mass concentration - described by a Sérsic function - and the disc - described by a broken exponential disc seen edge-on. Our improved treatment fully confirms the ubiquitous occurrence of thick discs. The main difference between our current fits and those presented in our previous papers is that now the scattered light from the thin disc dominates the surface brightness at levels below μ 26 mag arcsec-2. We stress that those extended thin disc tails are not physical, but pure scattered light. This change, however, does not drastically affect any of our previously presented results: 1) Thick discs are nearly ubiquitous. They are not an artefact caused by scattered light as has been suggested elsewhere. 2) Thick discs have masses comparable to those of thin discs in low-mass galaxies - with circular velocities vc< 120 km s-1 - whereas they are typically less massive than the thin discs in high-mass galaxies. 3) Thick discs and central mass concentrations seem to have formed at the same epoch from a common material reservoir. 4) Approximately 50% of the up

  4. Microfabrication and Magnetic Particle Spectrometry of Magnetic Discs

    NARCIS (Netherlands)

    Löthman, Per Arvid; Janson, T.G.; Klein, Yannick Philippe; Blaudszun, André-René; Ledwig, Michael; Abelmann, Leon

    2017-01-01

    We report on the fabrication of dispersions of Au/Ni81Fe19/Au magnetic discs with two and three micrometer diameter and thickness in the order of hundred nanometers. The magnetisation reversal of the discs was analysed on a time-scale of an hour as well as a few milliseconds to asses their

  5. Study of discography (CTD) for the cervical disc disorders

    Energy Technology Data Exchange (ETDEWEB)

    Tsuru, Takayuki; Maekawa, Kiyotsugu; Morita, Sunao; Mizuno, Hideo

    1985-07-01

    Twenty patients suffering from the cervical disc disorders were examined by CT scan after cervical discography. Cervical discs are situated in horizontal plane and contrast medium spreads in horizontal course. The horizontal analysis obtained by CT discography supplies several new findings useful to diagnosis and surgical treatment. Especially it can correct the false negative or the false positive findings of other radiological examinations.

  6. Adaptive repetitive control of a compact disc mechanism

    NARCIS (Netherlands)

    Dötsch, H.G.M.; Smakman, H.T.; Hof, Van den P.M.J.; Steinbuch, M.

    1995-01-01

    Radial track following of a compact disc player servo mechanism is severely exposed to periodic disturbances, induced by the eccentric rotation of the disc. The period of this disturbance is not available for measurement and varies slowly in time. Periodic disturbances can be adequately attenuated

  7. Goddard Earth Science Data and Information Center (GES DISC)

    Science.gov (United States)

    Kempler, Steve

    2016-01-01

    The GES DIS is one of 12 NASA Earth science data centers. The GES DISC vision is to enable researchers and educators maximize knowledge of the Earth by engaging in understanding their goals, and by leading the advancement of remote sensing information services in response to satisfying their goals. This presentation will describe the GES DISC approach, successes, challenges, and best practices.

  8. Welded rupture disc assemblies for use in Tritium Research Laboratory

    International Nuclear Information System (INIS)

    Faltings, R.E.

    1976-01-01

    Welded rupture disc assemblies were investigated and developed in various ranges for probable use by experimenters in their activities in the Tritium Research Laboratory at Sandia Laboratories, Livermore. This study indicates that currently welded rupture disc assemblies with appropriate testing and installation by certified pressure installers may be used in pressure systems in the Tritium Research Laboratory and other areas at SLL

  9. Effect of chewing upon disc reduction in the temporomandibular joint

    NARCIS (Netherlands)

    Kalaykova, S.; Lobbezoo, F.; Naeije, M.

    2011-01-01

    Aims: To test whether an intensive chewing exercise influences the moment of disc reduction in subjects with or without reports of intermittent locking of the jaw. Methods: This experimental study included 15 subjects with a reducing anteriorly displaced disc (ADD) and with symptoms of intermittent

  10. Surgical treatment of foraminal herniated disc of the lumbar spine

    OpenAIRE

    Halikov Shavkatbek; Abduhalikov Alimjon Karimjanovich

    2017-01-01

    Herniated lumbar intervertebral disc have a significant impact on both the patient’s life as well, and because of the high prevalence and economic impact on society as a whole. Designed scheduling algorithm foraminal hernia surgical treatment of lumbar intervertebral disc, based on the preoperative detection of compressing factors allows to define differentiated indications for decompressive or decompressive-stabilizing surgery.

  11. Avoiding failures of steam turbine discs by automated ultrasonic inspections

    International Nuclear Information System (INIS)

    Morton, J.; Bird, C.R.

    1994-01-01

    Under certain conditions, stress corrosion cracking can cause catastrophic failure of steam turbine discs. Nuclear Electric has developed a range of inspection techniques for disc keyways, bores, buttons and blade attachments and has accumulated substantial experience on their use on plant. This paper gives examples of the techniques used and discusses the strengths and weaknesses of the techniques applied

  12. The mathematics of the compact disc (Chapter 2)

    NARCIS (Netherlands)

    van Lint, J.H.; Aigner, M.; Behrends, E.

    2010-01-01

    Everyone uses compact discs nowadays. But why is the musical transfer to a CD purer than that of the traditional vinyl disc? The answer, to adapt a popular slogan, is: There is mathematics inside! More precisely, a branch of discrete mathematics, namely the theory of error correcting codes. This

  13. Method for improved reading of a digital data disc

    DEFF Research Database (Denmark)

    2004-01-01

    Method for regulating the control signal for adjustment of the optical path between a data disc and a signal pick-up detector system in a data disc drive, where the control is regulated as a response to the deviation of the actual reading signals from expected reading signals, and wherein...

  14. Morning glory disc anomaly: A case report | Saraswat | Nigerian ...

    African Journals Online (AJOL)

    Morning glory disc anomaly: A case report. Neeraj K. Saraswat, Ravi Ranjan, Dipendra Shukla, Sushil Ojha. Abstract. A rare case of congenital anomaly of the optic disc is presented to draw attention to the occurrence of this anomaly in rural India. The typical case presented with excavated, enlarged colobomatous optic ...

  15. Avoiding failures of steam turbine discs by automated ultrasonic inspections

    International Nuclear Information System (INIS)

    Bird, C.R.; Morton, J.

    1994-01-01

    Under certain conditions, stress corrosion cracking can cause catastrophic failure of steam turbine discs. Nuclear Electric has developed a range of inspection techniques for disc keyways, bores, buttons and blade attachments and has accumulated substantial experience on their use on plant. This paper gives examples of the techniques used and discusses the strengths and weaknesses of the techniques applied. (Author)

  16. Spiral density waves and vertical circulation in protoplanetary discs

    Science.gov (United States)

    Riols, A.; Latter, H.

    2018-06-01

    Spiral density waves dominate several facets of accretion disc dynamics - planet-disc interactions and gravitational instability (GI) most prominently. Though they have been examined thoroughly in two-dimensional simulations, their vertical structures in the non-linear regime are somewhat unexplored. This neglect is unwarranted given that any strong vertical motions associated with these waves could profoundly impact dust dynamics, dust sedimentation, planet formation, and the emissivity of the disc surface. In this paper, we combine linear calculations and shearing box simulations in order to investigate the vertical structure of spiral waves for various polytropic stratifications and wave amplitudes. For sub-adiabatic profiles, we find that spiral waves develop a pair of counter-rotating poloidal rolls. Particularly strong in the non-linear regime, these vortical structures issue from the baroclinicity supported by the background vertical entropy gradient. They are also intimately connected to the disc's g modes which appear to interact non-linearly with the density waves. Furthermore, we demonstrate that the poloidal rolls are ubiquitous in gravitoturbulence, emerging in the vicinity of GI spiral wakes, and potentially transporting grains off the disc mid-plane. Other than hindering sedimentation and planet formation, this phenomena may bear on observations of the disc's scattered infrared luminosity. The vortical features could also impact on the turbulent dynamo operating in young protoplanetary discs subject to GI, or possibly even galactic discs.

  17. Spine imaging after lumbar disc replacement: pitfalls and current recommendations

    OpenAIRE

    Robinson, Yohan; Sand?n, Bengt

    2009-01-01

    Abstract Background Most lumbar artificial discs are still composed of stainless steel alloys, which prevents adequate postoperative diagnostic imaging of the operated region when using magnetic resonance imaging (MRI). Thus patients with postoperative radicular symptoms or claudication after stainless steel implants often require alternative diagnostic procedures. Methods Possible complications of lumbar total disc replacement (TDR) are reviewed from the available literature and imaging reco...

  18. Utility of Digital Stereo Images for Optic Disc Evaluation

    Science.gov (United States)

    Ying, Gui-shuang; Pearson, Denise J.; Bansal, Mayank; Puri, Manika; Miller, Eydie; Alexander, Judith; Piltz-Seymour, Jody; Nyberg, William; Maguire, Maureen G.; Eledath, Jayan; Sawhney, Harpreet

    2010-01-01

    Purpose. To assess the suitability of digital stereo images for optic disc evaluations in glaucoma. Methods. Stereo color optic disc images in both digital and 35-mm slide film formats were acquired contemporaneously from 29 subjects with various cup-to-disc ratios (range, 0.26–0.76; median, 0.475). Using a grading scale designed to assess image quality, the ease of visualizing optic disc features important for glaucoma diagnosis, and the comparative diameters of the optic disc cup, experienced observers separately compared the primary digital stereo images to each subject's 35-mm slides, to scanned images of the same 35-mm slides, and to grayscale conversions of the digital images. Statistical analysis accounted for multiple gradings and comparisons and also assessed image formats under monoscopic viewing. Results. Overall, the quality of primary digital color images was judged superior to that of 35-mm slides (P digital color images were mostly equivalent to the scanned digitized images of the same slides. Color seemingly added little to grayscale optic disc images, except that peripapillary atrophy was best seen in color (P digital over film images was maintained under monoscopic viewing conditions. Conclusions. Digital stereo optic disc images are useful for evaluating the optic disc in glaucoma and allow the application of advanced image processing applications. Grayscale images, by providing luminance distinct from color, may be informative for assessing certain features. PMID:20505199

  19. 21 CFR 872.3970 - Interarticular disc prosthesis (interpositional implant).

    Science.gov (United States)

    2010-04-01

    ... implant). 872.3970 Section 872.3970 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3970 Interarticular disc prosthesis (interpositional implant). (a) Identification. An interarticular disc prosthesis...

  20. Reliability of MRI findings in candidates for lumbar disc prosthesis

    International Nuclear Information System (INIS)

    Berg, Linda; Espeland, Ansgar; Neckelmann, Gesche; Gjertsen, Oeivind; Hellum, Christian; Johnsen, Lars G.; Eide, Geir E.

    2012-01-01

    Limited reliability data exist for localised magnetic resonance imaging (MRI) findings relevant to planning of treatment with lumbar disc prosthesis and later outcomes. We assessed the reliability of such findings in chronic low back pain patients who were accepted candidates for disc prosthesis. On pretreatment MRI of 170 patients (mean age 41 years; 88 women), three experienced radiologists independently rated Modic changes, disc findings and facet arthropathy at L3/L4, L4/L5 and L5/S1. Two radiologists rerated 126 examinations. For each MRI finding at each disc level, agreement was analysed using the kappa statistic and differences in prevalence across observers using a fixed effects model. All findings at L3/L4 and facet arthropathy at L5/S1 had a mean prevalence <10% across observers and were not further analysed, ensuring interpretable kappa values. Overall interobserver agreement was generally moderate or good (kappa 0.40-0.77) at L4-S1 for Modic changes, nucleus pulposus signal, disc height (subjective and measured), posterior high-intensity zone (HIZ) and disc contour, and fair (kappa 0.24) at L4/L5 for facet arthropathy. Posterior HIZ at L5/S1 and severely reduced subjective disc height at L4/L5 differed up to threefold in prevalence between observers (p < 0.0001). Intraobserver agreement was mostly good or very good (kappa 0.60-1.00). In candidates for disc prosthesis, mostly moderate interobserver agreement is expected for localised MRI findings. (orig.)