Usher syndrome type 1-associated cadherins shape the photoreceptor outer segment.

PubMed

Schietroma, Cataldo; Parain, Karine; Estivalet, Amrit; Aghaie, Asadollah; Boutet de Monvel, Jacques; Picaud, Serge; Sahel, José-Alain; Perron, Muriel; El-Amraoui, Aziz; Petit, Christine

2017-06-05

Usher syndrome type 1 (USH1) causes combined hearing and sight defects, but how mutations in USH1 genes lead to retinal dystrophy in patients remains elusive. The USH1 protein complex is associated with calyceal processes, which are microvilli of unknown function surrounding the base of the photoreceptor outer segment. We show that in Xenopus tropicalis , these processes are connected to the outer-segment membrane by links composed of protocadherin-15 (USH1F protein). Protocadherin-15 deficiency, obtained by a knockdown approach, leads to impaired photoreceptor function and abnormally shaped photoreceptor outer segments. Rod basal outer disks displayed excessive outgrowth, and cone outer segments were curved, with lamellae of heterogeneous sizes, defects also observed upon knockdown of Cdh23 , encoding cadherin-23 (USH1D protein). The calyceal processes were virtually absent in cones and displayed markedly reduced F-actin content in rods, suggesting that protocadherin-15-containing links are essential for their development and/or maintenance. We propose that calyceal processes, together with their associated links, control the sizing of rod disks and cone lamellae throughout their daily renewal. © 2017 Schietroma et al.

Pre-stressed/pre-compressed gas turbine nozzle

DOEpatents

Jang, Hoyle; Itzel, Gary Michael; Yu, Yufeng Phillip

2002-01-01

A method of increasing low cycle fatigue life of a turbine nozzle comprising a plurality of stationary airfoils extending between radially inner and outer ring segments comprising a) providing at least one radial passage in each of the plurality of airfoils; b) installing a rod in the radial passage extending between the radially inner and outer ring segments and fixing one end of the rod to one of the inner and outer rings; and c) pre-loading the rod to compress the airfoil between the inner and outer ring segments.

The membrane current of single rod outer segments.

PubMed

Baylor, D A; Lamb, T D; Yau, K W

1979-03-01

1. Outer segments of individual rods in the retina of the toad, Bufo marinus, were drawn into a glass pipette to record the membrane current. 2. Light flashes evoked transient outward currents. The peak response amplitude was related to flash intensity by a Michaelis equation with half-saturating intensity about 1 photon mum-2. 3. The saturating response amplitude ranged up to 27 pA and corresponded closely to complete suppression of the steady inward current present in darkness. 4. For a given cell the saturating response amplitude varied linearly with the length of outer segment within the pipette. This is consistent with a uniform density of light-sensitive channels and negligible gradient of membrane potential along the outer segment. 5. Responses to bright flashes never showed the relaxation from an initial peak seen previously in intracellular voltage recordings, suggesting that the conductance change responsible for the relaxation does not occur in the outer segment. 6. Responses to local illumination of only the recorded outer segment were very similar to those obtained with diffuse light at the same intensity, indicating that peripheral rods made little contribution to the responses. 7. The spectral sensitivity of 'red' rods was consistent with a retinal1-based pigment with lambda max = 498 +/- 2 nm. 8. The kinetics of the response were consistent with four stages of delay affecting action of the internal transmitter. Responses were faster at the basal end of the outer segment than at the distal tip. 9. Background light reduced the sensitivity to a superposed dim test flash and shortened the time course of the response, indicating that adapting light modifies the kinetics and gain of the transduction mechanism within the outer segment. 10. Responses to dim lights exhibited pronounced fluctuations which are attributed in the succeeding paper (Baylor, Lamb & Yau, 1979) to the quantal nature of light.

Functional significance of the taper of vertebrate cone photoreceptors

PubMed Central

Hárosi, Ferenc I.

2012-01-01

Vertebrate photoreceptors are commonly distinguished based on the shape of their outer segments: those of cones taper, whereas the ones from rods do not. The functional advantages of cone taper, a common occurrence in vertebrate retinas, remain elusive. In this study, we investigate this topic using theoretical analyses aimed at revealing structure–function relationships in photoreceptors. Geometrical optics combined with spectrophotometric and morphological data are used to support the analyses and to test predictions. Three functions are considered for correlations between taper and functionality. The first function proposes that outer segment taper serves to compensate for self-screening of the visual pigment contained within. The second function links outer segment taper to compensation for a signal-to-noise ratio decline along the longitudinal dimension. Both functions are supported by the data: real cones taper more than required for these compensatory roles. The third function relates outer segment taper to the optical properties of the inner compartment whereby the primary determinant is the inner segment’s ability to concentrate light via its ellipsoid. In support of this idea, the rod/cone ratios of primarily diurnal animals are predicted based on a principle of equal light flux gathering between photoreceptors. In addition, ellipsoid concentration factor, a measure of ellipsoid ability to concentrate light onto the outer segment, correlates positively with outer segment taper expressed as a ratio of characteristic lengths, where critical taper is the yardstick. Depending on a light-funneling property and the presence of focusing organelles such as oil droplets, cone outer segments can be reduced in size to various degrees. We conclude that outer segment taper is but one component of a miniaturization process that reduces metabolic costs while improving signal detection. Compromise solutions in the various retinas and retinal regions occur between ellipsoid size and acuity, on the one hand, and faster response time and reduced light sensitivity, on the other. PMID:22250013

Method of fabricating a prestressed cast iron vessel

DOEpatents

Lampe, Robert F.

1982-01-01

A method of fabricating a prestressed cast iron vessel wherein double wall cast iron body segments each have an arcuate inner wall and a spaced apart substantially parallel outer wall with a plurality of radially extending webs interconnecting the inner wall and the outer wall, the bottom surface and the two exposed radial side surfaces of each body segment are machined and eight body segments are formed into a ring. The top surfaces and outer surfaces of the outer walls are machined and keyways are provided across the juncture of adjacent end walls of the body segments. A liner segment complementary in shape to a selected inner wall of one of the body segments is mounted to each of the body segments and again formed into a ring. The liner segments of each ring are welded to form unitary liner rings and thereafter the cast iron body segments are prestressed to complete the ring assembly. Ring assemblies are stacked to form the vessel and adjacent unitary liner rings are welded. A top head covers the top ring assembly to close the vessel and axially extending tendons retain the top and bottom heads in place under pressure.

Role of subunit assembly in autosomal dominant retinitis pigmentosa linked to mutations in peripherin 2.

PubMed

Molday, Robert S; Molday, Laurie L; Loewen, Christopher J R

2004-01-01

Peripherin 2 is a photoreceptor-specific membrane protein implicated in outer segment disk morphogenesis and linked to various retinopathies including autosomal dominant retinitis pigmentosa (ADRP). Peripherin 2 and ROM1 assemble as a mixture of core noncovalent homomeric and heteromeric tetramers that further link together through disulfide bonds to form higher order oligomers. These complexes are critical for disk rim formation and outer segment structure through interaction with the cGMP-gated channel and other photoreceptor proteins. We have examined the role of subunit assembly in peripherin 2 targeting to disks, outer segment structure, and photoreceptor degeneration by examining molecular and cellular properties of peripherin 2 mutants in COS-1 cells and transgenic Xenopus laevis rod photoreceptors. Wild-type (WT) and the ADRP-linked P216L mutant were transported and incorporated into newly formed outer segment disks of transgenic X. laevis. The P216L mutant, however, induced progressive outer segment instability and photoreceptor degeneration possibly through the introduction of a new N-linked oligosaccharide chain. In contrast, the C214S and L185P disease-linked, tetramerization-defective mutants, were retained in the inner segment, but did not affect outer segment structure or induce photoreceptor degeneration. Together, these results indicate that peripherin 2 mutations can cause ADRP either through a deficiency in WT peripherin 2 (C214S, 1.185P) or by a dominant negative effect on disk stability (P216L).

THE STRUCTURE AND CONCENTRATION OF SOLIDS IN PHOTORECEPTOR CELLS STUDIED BY REFRACTOMETRY AND INTERFERENCE MICROSCOPY

PubMed Central

Sidman, Richard L.

1957-01-01

Fragments of freshly obtained retinas of several vertebrate species were studied by refractometry, with reference to the structure of the rods and cones. The findings allowed a reassessment of previous descriptions based mainly on fixed material. The refractometric method was used also to measure the refractice indices and to calculate the concentrations of solids and water in the various cell segments. The main quantitative data were confirmed by interference microscopy. When examined by the method of refractometry the outer segments of freshly prepared retinal rods appear homogeneous. Within a few minutes a single eccentric longitudinal fiber appears, and transverse striations may develop. These changes are attributed to imbibition of water and swelling in structures normally too small for detection by light microscopy. The central "core" of outer segments and the chromophobic disc between outer and inner segments appear to be artifacts resulting from shrinkage during dehydration. The fresh outer segments of cones, and the inner segments of rods and cones also are described and illustrated. The volumes, refractive indices, concentrations of solids, and wet and dry weights of various segments of the photoreceptor cells were tabulated. Rod outer segments of the different species vary more than 100-fold in volume and mass but all have concentrations of solids of 40 to 43 per cent. Cone outer segments contain only about 30 per cent solids. The myoids, paraboloids, and ellipsoids of the inner segments likewise have characteristic refractive indices and concentrations of solids. Some of the limitations and particular virtues of refractometry as a method for quantitative analysis of living cells are discussed in comparison with more conventional biochemical techniques. Also the shapes and refractive indices of the various segments of photoreceptor cells are considered in relation to the absorption and transmission of light. The Stiles-Crawford effect can be accounted for on the basis of the structure of cone cells. PMID:13416308

Extra-mitochondrial aerobic metabolism in retinal rod outer segments: new perspectives in retinopathies.

PubMed

Panfoli, I; Calzia, D; Ravera, S; Morelli, A M; Traverso, C E

2012-04-01

Vertebrate retinal rods are photoreceptors for dim-light vision. They display extreme sensitivity to light thanks to a specialized subcellular organelle, the rod outer segment. This is filled with a stack of membranous disks, expressing the proteins involved in visual transduction, a very energy demanding process. Our previous proteomic and biochemical studies have shed new light on the chemical energy processes that supply ATP to the outer segment, suggesting the presence of an extra-mitochondrial aerobic metabolism in rod outer segment, devoid of mitochondria, which would account for a quantitatively adequate ATP supply for phototransduction. Here the functional presence of an oxidative phosphorylation in the rod outer limb is examined for its relationship to many physiological and pathological data on the rod outer segment. We hypothesize that the rod outer limb is at risk of oxidative stress, in any case of impairment in the respiratory chain functioning, or of blood supply. In fact, the electron transfer chain is a major source of reactive O(2) species, known to produce severe alteration to the membrane lipids, especially those of the outer segment that are rich in polyunsaturated fatty acids. We propose that the disk membrane may become the target of reactive oxygen species that may be released by the electron transport chain under pathologic conditions. For example, during aging reactive oxygen species production increases, while cellular antioxidant capacity decreases. Also the apoptosis of the rod observed after exposure to bright or continuous illumination can be explained considering that an overfunctioning of phototransduction may damage the disk membrane to a point at which cytochrome c escapes from the intradiskal space, where it is presently supposed to be, activating a putative caspase 9 and the apoptosome. A pathogenic mechanism for many inherited and acquired retinal degenerations, representing a major problem in clinical ophthalmology, is proposed: a number of rod pathologies would be promoted by impairment of energy supply and/or oxidative stress in the rod outer segment. In conclusion we suppose that the damaging role of oxygen, be it hypoxia or hyperoxia invoked in most of the blinding diseases, acquired and even hereditary is to be seeked for inside the photoreceptor outer segment that would conceal a potential for cell death that is still to be recognized. Copyright © 2012 Elsevier Ltd. All rights reserved.

Localization of Usher 1 proteins to the photoreceptor calyceal processes, which are absent from mice.

PubMed

Sahly, Iman; Dufour, Eric; Schietroma, Cataldo; Michel, Vincent; Bahloul, Amel; Perfettini, Isabelle; Pepermans, Elise; Estivalet, Amrit; Carette, Diane; Aghaie, Asadollah; Ebermann, Inga; Lelli, Andrea; Iribarne, Maria; Hardelin, Jean-Pierre; Weil, Dominique; Sahel, José-Alain; El-Amraoui, Aziz; Petit, Christine

2012-10-15

The mechanisms underlying retinal dystrophy in Usher syndrome type I (USH1) remain unknown because mutant mice lacking any of the USH1 proteins-myosin VIIa, harmonin, cadherin-23, protocadherin-15, sans-do not display retinal degeneration. We found here that, in macaque photoreceptor cells, all USH1 proteins colocalized at membrane interfaces (i) between the inner and outer segments in rods and (ii) between the microvillus-like calyceal processes and the outer segment basolateral region in rods and cones. This pattern, conserved in humans and frogs, was mediated by the formation of an USH1 protein network, which was associated with the calyceal processes from the early embryonic stages of outer segment growth onwards. By contrast, mouse photoreceptors lacked calyceal processes and had no USH1 proteins at the inner-outer segment interface. We suggest that USH1 proteins form an adhesion belt around the basolateral region of the photoreceptor outer segment in humans, and that defects in this structure cause the retinal degeneration in USH1 patients.

Localization of Usher 1 proteins to the photoreceptor calyceal processes, which are absent from mice

PubMed Central

Sahly, Iman; Dufour, Eric; Schietroma, Cataldo; Michel, Vincent; Bahloul, Amel; Perfettini, Isabelle; Pepermans, Elise; Estivalet, Amrit; Carette, Diane; Aghaie, Asadollah; Ebermann, Inga; Lelli, Andrea; Iribarne, Maria; Hardelin, Jean-Pierre; Weil, Dominique; Sahel, José-Alain

2012-01-01

The mechanisms underlying retinal dystrophy in Usher syndrome type I (USH1) remain unknown because mutant mice lacking any of the USH1 proteins—myosin VIIa, harmonin, cadherin-23, protocadherin-15, sans—do not display retinal degeneration. We found here that, in macaque photoreceptor cells, all USH1 proteins colocalized at membrane interfaces (i) between the inner and outer segments in rods and (ii) between the microvillus-like calyceal processes and the outer segment basolateral region in rods and cones. This pattern, conserved in humans and frogs, was mediated by the formation of an USH1 protein network, which was associated with the calyceal processes from the early embryonic stages of outer segment growth onwards. By contrast, mouse photoreceptors lacked calyceal processes and had no USH1 proteins at the inner–outer segment interface. We suggest that USH1 proteins form an adhesion belt around the basolateral region of the photoreceptor outer segment in humans, and that defects in this structure cause the retinal degeneration in USH1 patients. PMID:23045546

Leaf seal for inner and outer casings of a turbine

DOEpatents

Schroder, Mark Stewart; Leach, David

2002-01-01

A plurality of arcuate, circumferentially extending leaf seal segments form an annular seal spanning between annular sealing surfaces of inner and outer casings of a turbine. The ends of the adjoining seal segments have circumferential gaps to enable circumferential expansion and contraction of the segments. The end of a first segment includes a tab projecting into a recess of a second end of a second segment. Edges of the tab seal against the sealing surfaces of the inner and outer casings have a narrow clearance with opposed edges of the recess. An overlying cover plate spans the joint. Leakage flow is maintained at a minimum because of the reduced gap between the radially spaced edges of the tab and recess, while the seal segments retain the capacity to expand and contract circumferentially.

Transcriptomic insights into citrus segment membrane's cell wall components relating to fruit sensory texture.

PubMed

Wang, Xun; Lin, Lijin; Tang, Yi; Xia, Hui; Zhang, Xiancong; Yue, Maolan; Qiu, Xia; Xu, Ke; Wang, Zhihui

2018-04-23

During fresh fruit consumption, sensory texture is one factor that affects the organoleptic qualities. Chemical components of plant cell walls, including pectin, cellulose, hemicellulose and lignin, play central roles in determining the textural qualities. To explore the genes and regulatory pathways involved in fresh citrus' perceived sensory texture, we performed mRNA-seq analyses of the segment membranes of two citrus cultivars, Shiranui and Kiyomi, with different organoleptic textures. Segment membranes were sampled at two developmental stages of citrus fruit, the beginning and end of the expansion period. More than 3000 differentially expressed genes were identified. The gene ontology analysis revealed that more categories were significantly enriched in 'Shiranui' than in 'Kiyomi' at both developmental stages. In total, 108 significantly enriched pathways were obtained, with most belonging to metabolism. A detailed transcriptomic analysis revealed potential critical genes involved in the metabolism of cell wall structures, for example, GAUT4 in pectin synthesis, CESA1, 3 and 6, and SUS4 in cellulose synthesis, CSLC5, XXT1 and XXT2 in hemicellulose synthesis, and CSE in lignin synthesis. Low levels, or no expression, of genes involved in cellulose and hemicellulose, such as CESA4, CESA7, CESA8, IRX9 and IRX14, confirmed that secondary cell walls were negligible or absent in citrus segment membranes. A chemical component analysis of the segment membranes from mature fruit revealed that the pectin, cellulose and lignin contents, and the segment membrane's weight (% of segment) were greater in 'Kiyomi'. Organoleptic quality of citrus is easily overlooked. It is mainly determined by sensory texture perceived in citrus segment membrane properties. We performed mRNA-seq analyses of citrus segment membranes to explore the genes and regulatory pathways involved in fresh citrus' perceived sensory texture. Transcriptomic data showed high repeatability between two independent biological replicates. The expression levels of genes involved in cell wall structure metabolism, including pectin, cellulose, hemicellulose and lignin, were investigated. Meanwhile, chemical component contents of the segment membranes from mature fruit were analyzed. This study provided detailed transcriptional regulatory profiles of different organoleptic citrus qualities and integrated insights into the mechanisms affecting citrus' sensory texture.

Reactor coolant pump flywheel

DOEpatents

Finegan, John Raymond; Kreke, Francis Joseph; Casamassa, John Joseph

2013-11-26

A flywheel for a pump, and in particular a flywheel having a number of high density segments for use in a nuclear reactor coolant pump. The flywheel includes an inner member and an outer member. A number of high density segments are provided between the inner and outer members. The high density segments may be formed from a tungsten based alloy. A preselected gap is provided between each of the number of high density segments. The gap accommodates thermal expansion of each of the number of segments and resists the hoop stress effect/keystoning of the segments.

Freeze-fracture studies of photoreceptor membranes: new observations bearing upon the distribution of cholesterol

PubMed Central

1983-01-01

We performed electron microscopy of replicas from freeze-fractured retinas exposed during or after fixation to the cholesterol-binding antibiotic, filipin. We observed characteristic filipin-induced perturbations throughout the disk and plasma membranes of retinal rod outer segments of various species. It is evident that a prolonged exposure to filipin in fixative enhances rather than reduces presumptive cholesterol detection in the vertebrate photoreceptor cell. In agreement with the pattern seen in our previous study (Andrews, L.D., and A. I. Cohen, 1979, J. Cell Biol., 81:215-228), filipin- binding in membranes exhibiting particle-free patches seemed largely confined to these patches. Favorably fractured photoreceptors exhibited marked filipin-binding in apical inner segment plasma membrane topologically confluent with and proximate to the outer segment plasma membrane, which was comparatively free of filipin binding. A possible boundary between these differing membrane domains was suggested in a number of replicas exhibiting lower filipin binding to the apical plasma membrane of the inner segment in the area surrounding the cilium. This area contains a structure (Andrews, L. D., 1982, Freeze- fracture studies of vertebrate photoreceptors, In Structure of the Eye, J. G. Hollyfield and E. Acosta Vidrio, editors, Elsevier/North-Holland, New York, 11-23) that resembles the active zones of the nerve terminals for the frog neuromuscular junction. These observations lead us to hypothesize that these structures may function to direct vesicle fusion to occur near them, in a domain of membrane more closely resembling outer than inner segment plasma membrane. The above evidence supports the views that (a) all disk membranes contain cholesterol, but the particle-free patches present in some disks trap cholesterol from contiguous particulate membrane regions; (b) contiguous inner and outer segment membranes may greatly differ in cholesterol content; and (c) the suggested higher cholesterol in the inner segment than in the outer segment plasma membrane may help direct newly inserted photopigment molecules to the outer segment. PMID:6411740

ARL2BP, a protein linked to Retinitis Pigmentosa, is needed for normal photoreceptor cilia doublets and outer segment structure.

PubMed

Moye, Abigail R; Singh, Ratnesh; Kimler, Victoria A; Dilan, Tanya L; Munezero, Daniella; Saravanan, Thamaraiselvi; Goldberg, Andrew F X; Ramamurthy, Visvanathan

2018-05-02

The outer segment (OS) of photoreceptor cells is an elaboration of a primary cilium with organized stacks of membranous discs that contain the proteins needed for phototransduction and vision. Though cilia formation and function has been well characterized, little is known about the role of cilia in the development of photoreceptor OS. Nevertheless, progress has been made by studying mutations in ciliary proteins which often result in malformed outer segments and lead to blinding diseases. To investigate how ciliary proteins contribute to outer segment formation, we generated a knockout mouse model for ARL2BP, a ciliary protein linked to Retinitis Pigmentosa. The knockout mice display an early and progressive reduction in visual response. Prior to photoreceptor degeneration we observed disorganization of the photoreceptor OS, with vertically aligned discs and shortened axonemes. Interestingly, ciliary doublet microtubule structure was also impaired, displaying open B-tubule doublets, paired with loss of singlet microtubules. Based on results from this study, we conclude that ARL2BP is necessary for photoreceptor cilia doublet formation and axoneme elongation, which is required for outer segment morphogenesis and vision.

Diffusion Tensor Imaging Based Thalamic Segmentation in Deep Brain Stimulation for Chronic Pain Conditions

PubMed Central

Kim, Won; Chivukula, Srinivas; Hauptman, Jason; Pouratian, Nader

2016-01-01

Background/Aims Thalamic deep brain stimulation (DBS) for the treatment of medically refractory pain has largely been abandoned on account of its inconsistent and oftentimes poor efficacy. Our aim here was to use diffusion tensor imaging (DTI)-based segmentation to assess the internal thalamic nuclei of patients who have undergone thalamic DBS for intractable pain and retrospectively correlate lead position with clinical outcome. Methods DTI-based segmentation was performed on 5 patients who underwent sensory thalamus DBS for chronic pain. Postoperative computed tomography (CT) images obtained for electrode placement were fused with preoperative MRIs that had undergone DTI-based thalamic segmentation. Sensory thalamus maps of 4 patients were analyzed for lead positioning and interpatient variability. Results Four patients who experienced significant pain relief following DBS demonstrated contact positions within the DTI-determined sensory thalamus or in its vicinity, whereas one who did not respond to stimulation did not. Only four voxels (2%) within the sensory thalamus were mutually shared among patients; 108 voxels (58%) were uniquely represented. Conclusions DTI-based segmentation of the thalamus can be used to confirm thalamic lead placement relative to the sensory thalamus, and may serve as a useful tool to guide thalamic DBS electrode implantation in the future. PMID:27537848

Glycolytic reliance promotes anabolism in photoreceptors

PubMed Central

Chinchore, Yashodhan; Begaj, Tedi; Wu, David; Drokhlyansky, Eugene; Cepko, Constance L

2017-01-01

Vertebrate photoreceptors are among the most metabolically active cells, exhibiting a high rate of ATP consumption. This is coupled with a high anabolic demand, necessitated by the diurnal turnover of a specialized membrane-rich organelle, the outer segment, which is the primary site of phototransduction. How photoreceptors balance their catabolic and anabolic demands is poorly understood. Here, we show that rod photoreceptors in mice rely on glycolysis for their outer segment biogenesis. Genetic perturbations targeting allostery or key regulatory nodes in the glycolytic pathway impacted the size of the outer segments. Fibroblast growth factor signaling was found to regulate glycolysis, with antagonism of this pathway resulting in anabolic deficits. These data demonstrate the cell autonomous role of the glycolytic pathway in outer segment maintenance and provide evidence that aerobic glycolysis is part of a metabolic program that supports the biosynthetic needs of a normal neuronal cell type. DOI: http://dx.doi.org/10.7554/eLife.25946.001 PMID:28598329

A FRAP-Based Method for Monitoring Molecular Transport in Ciliary Photoreceptor Cells In Vivo.

PubMed

Wunderlich, Kirsten A; Wolfrum, Uwe

2016-01-01

The outer segment of rod and cone photoreceptor cells represents a highly modified primary sensory cilium. It renews on a daily basis throughout lifetime and effective vectorial transport to the cilium is essential for the maintenance of the photoreceptor cell function. Defects in molecules of transport modules lead to severe retinal ciliopathies. We have recently established a fluorescence recovery after photobleaching (FRAP)-based method to monitor molecular trafficking in living rodent photoreceptor cells. We irreversibly bleach the fluorescence of tagged molecules (e.g. eGFP-Rhodopsin) in photoreceptor cells of native vibratome sections through the retina by high laser intensity. In the laser scanning microscope, the recovery of the fluorescent signal is monitored over time and the kinetics of movements of molecules can be quantitatively ascertained.

The retina visual cycle is driven by cis retinol oxidation in the outer segments of cones

PubMed Central

Sato, Shinya; Frederiksen, Rikard; Cornwall, M. Carter; Kefalov, Vladimir J.

2017-01-01

Vertebrate rod and cone photoreceptors require continuous supply of chromophore for regenerating their visual pigments after photoactivation. Cones, which mediate our daytime vision, demand a particularly rapid supply of 11-cis retinal chromophore in order to maintain their function in bright light. An important contribution to this process is thought to be the chromophore precursor 11-cis retinol, which is supplied to cones from Müller cells in the retina and subsequently oxidized to 11-cis retinal as part of the retina visual cycle. However, the molecular identity of the cis retinol oxidase in cones remains unclear. Here, as a first step in characterizing this enzymatic reaction, we sought to determine the subcellular localization of this activity in salamander red cones. We found that the onset of dark adaptation of isolated salamander red cones was substantially faster when exposing directly their outer vs. their inner segment to 9-cis retinol, an analogue of 11-cis retinol. In contrast, this difference was not observed when treating the outer vs. inner segment with 9-cis retinal, a chromophore analogue which can directly support pigment regeneration. These results suggest, surprisingly, that the cis-retinol oxidation occurs in the outer segments of cone photoreceptors. Confirming this notion, pigment regeneration with exogenously added 9-cis retinol was directly observed in the truncated outer segments of cones, but not in rods. We conclude that the enzymatic machinery required for the oxidation of recycled cis retinol as part of the retina visual cycle is present in the outer segments of cones. PMID:28359344

Segmental somatosensory-evoked potentials as a diagnostic tool in chronic inflammatory demyelinating polyneuropathies, and other sensory neuropathies.

PubMed

Koutlidis, R M; Ayrignac, X; Pradat, P-F; Le Forestier, N; Léger, J-M; Salachas, F; Maisonobe, T; Fournier, E; Viala, K

2014-09-01

Somatosensory-evoked potentials with segmental recordings were performed with the aim of distinguishing chronic inflammatory demyelinating polyneuropathy from other sensory neuropathies. Four groups of 20 subjects each corresponded to patients with (1) possible sensory chronic inflammatory demyelinating polyneuropathy, (2) patients with sensory polyneuropathy of unknown origin, (3) patients with amyotrophic lateral sclerosis and (4) normal subjects. The patients selected for this study had preserved sensory potentials on electroneuromyogram and all waves were recordable in evoked potentials. Somatosensory-evoked potentials evaluations were carried out by stimulation of the posterior tibial nerve at the ankle, recording peripheral nerve potential in the popliteal fossa, radicular potential and spinal potential at the L4-L5 and T12 levels, and cortical at C'z, with determination of distal conduction time, proximal and radicular conduction time and central conduction time. In the group of chronic inflammatory demyelinating polyneuropathy, 80% of patients had abnormal conduction in the N8-N22 segment and 95% had abnormal N18-N22 conduction time. In the group of neuropathies, distal conduction was abnormal in most cases, whereas 60% of patients had no proximal abnormality. None of the patients in the group of amyotrophic lateral sclerosis had an abnormal N18-N22 conduction time. Somatosensory-evoked potentials with segmental recording can be used to distinguish between atypical sensory chronic inflammatory demyelinating polyneuropathy and other sensory neuropathies, at the early stage of the disease. Graphical representation of segmental conduction times provides a rapid and accurate visualization of the profile of each patient. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

S-net : Construction of large scale seafloor observatory network for tsunamis and earthquakes along the Japan Trench

NASA Astrophysics Data System (ADS)

Mochizuki, M.; Uehira, K.; Kanazawa, T.; Shiomi, K.; Kunugi, T.; Aoi, S.; Matsumoto, T.; Sekiguchi, S.; Yamamoto, N.; Takahashi, N.; Nakamura, T.; Shinohara, M.; Yamada, T.

2017-12-01

NIED has launched the project of constructing a seafloor observatory network for tsunamis and earthquakes after the occurrence of the 2011 Tohoku Earthquake to enhance reliability of early warnings of tsunamis and earthquakes. The observatory network was named "S-net". The S-net project has been financially supported by MEXT.The S-net consists of 150 seafloor observatories which are connected in line with submarine optical cables. The total length of submarine optical cable is about 5,500 km. The S-net covers the focal region of the 2011 Tohoku Earthquake and its vicinity regions. Each observatory equips two units of a high sensitive pressure gauges as a tsunami meter and four sets of three-component seismometers. The S-net is composed of six segment networks. Five of six segment networks had been already installed. Installation of the last segment network covering the outer rise area have been finally finished by the end of FY2016. The outer rise segment has special features like no other five segments of the S-net. Those features are deep water and long distance. Most of 25 observatories on the outer rise segment are located at the depth of deeper than 6,000m WD. Especially, three observatories are set on the seafloor of deeper than about 7.000m WD, and then the pressure gauges capable of being used even at 8,000m WD are equipped on those three observatories. Total length of the submarine cables of the outer rise segment is about two times longer than those of the other segments. The longer the cable system is, the higher voltage supply is needed, and thus the observatories on the outer rise segment have high withstanding voltage characteristics. We employ a dispersion management line of a low loss formed by combining a plurality of optical fibers for the outer rise segment cable, in order to achieve long-distance, high-speed and large-capacity data transmission Installation of the outer rise segment was finished and then full-scale operation of S-net has started. All the data from 150 seafloor observatories are being transferred to and stored in the Tsukuba DC. Some data are being transmitted directly to JMA and have been used for monitoring of earthquakes and tsunamis. We will report construction and operation of the S-net system as well as the outline of the obtained data in this presentation.

The retinal phenotype of Usher syndrome: pathophysiological insights from animal models.

PubMed

El-Amraoui, Aziz; Petit, Christine

2014-03-01

The Usher syndrome (USH) is the most prevalent cause of inherited deaf-blindness. Three clinical subtypes, USH1-3, have been defined, and ten USH genes identified. The hearing impairment due to USH gene defects has been shown to result from improper organisation of the hair bundle, the sound receptive structure of sensory hair cells. In contrast, the cellular basis of the visual defect is less well understood as this phenotype is absent in almost all the USH mouse models that faithfully mimic the human hearing impairment. Structural and molecular interspecies discrepancies regarding photoreceptor calyceal processes and the association with the distribution of USH1 proteins have recently been unravelled, and have led to the conclusion that a defect in the USH1 protein complex-mediated connection between the photoreceptor outer segment and the surrounding calyceal processes (in both rods and cones), and the inner segment (in rods only), probably causes the USH1 retinal dystrophy in humans. Copyright © 2013 Académie des sciences. Published by Elsevier SAS. All rights reserved.

Photoreceptor change and visual outcome after idiopathic epiretinal membrane removal with or without additional internal limiting membrane peeling.

PubMed

Ahn, Seong Joon; Ahn, Jeeyun; Woo, Se Joon; Park, Kyu Hyung

2014-01-01

To compare the postoperative photoreceptor status and visual outcome after epiretinal membrane removal with or without additional internal limiting membrane (ILM) peeling. Medical records of 40 eyes from 37 patients undergoing epiretinal membrane removal with residual ILM peeling (additional ILM peeling group) and 69 eyes from 65 patients undergoing epiretinal membrane removal without additional ILM peeling (no additional peeling group) were reviewed. The length of defects in cone outer segment tips, inner segment/outer segment junction, and external limiting membrane line were measured using spectral domain optical coherence tomography images of the fovea before and at 1, 3, 6, and 12 months after the surgery. Cone outer segment tips and inner segment/outer segment junction line defects were most severe at postoperative 1 month and gradually restored at 12 months postoperatively. The cone outer segment tips line defect in the additional ILM peeling group was significantly greater than that in the no additional peeling group at postoperative 1 month (P = 0.006), and best-corrected visual acuity was significantly worse in the former group at the same month (P = 0.001). There was no significant difference in the defect size and best-corrected visual acuity at subsequent visits and recurrence rates between the two groups. Patients who received epiretinal membrane surgery without additional ILM peeling showed better visual and anatomical outcome than those with additional ILM peeling at postoperative 1 month. However, surgical outcomes were comparable between the two groups, thereafter. In terms of visual outcome and photoreceptor integrity, additional ILM peeling may not be an essential procedure.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, Gary L.; Shaffer, James E.

1997-01-01

An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, G.L.; Shaffer, J.E.

1997-01-07

An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, Gary L.; Shaffer, James E.

1996-01-01

An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, G.L.; Shaffer, J.E.

1996-09-10

An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, Gary L.; Shaffer, James E.

1995-01-01

An axial flow turbine's nozzle/nozzle support structure having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse.

Turbine nozzle/nozzle support structure

DOEpatents

Boyd, G.L.; Shaffer, J.E.

1995-08-15

An axial flow turbine`s nozzle/nozzle support structure is described having a cantilevered nozzle outer structure including an outer shroud and airfoil vanes extending radially inwardly therefrom, an inner shroud radially adjacent the inner end of the airfoil vanes and cooperatively disposed relative to the outer shroud to provide an annular fluid flow path, an inner and an outer support ring respectively arranged radially inside the inner shroud and axially adjacent a portion of the outer shroud, and pins extending through such portion and into the outer support ring. The inner support ring or inner shroud has a groove therein bounded by end walls for receiving and being axially abuttable with a locating projection from the adjacent airfoil vane, inner shroud, or inner support ring. The nozzle outer structure may comprise segments each of which has a single protrusion which is axially engageable with the outer support ring or, alternatively, a first and second protrusion which are arcuately and axially separated and which include axial openings therein whereby first and second protrusions on respective, arcuately adjacent nozzle segments have axial openings therein which are alignable with connector openings in the outer support ring and within each of such aligned openings a pin is receivable. The inner shroud may, likewise, comprise segments which, when assembled in operating configuration, have a 360 degree expanse. 6 figs.

Detection and visualization of endoleaks in CT data for monitoring of thoracic and abdominal aortic aneurysm stents

NASA Astrophysics Data System (ADS)

Lu, J.; Egger, J.; Wimmer, A.; Großkopf, S.; Freisleben, B.

2008-03-01

In this paper we present an efficient algorithm for the segmentation of the inner and outer boundary of thoratic and abdominal aortic aneurysms (TAA & AAA) in computed tomography angiography (CTA) acquisitions. The aneurysm segmentation includes two steps: first, the inner boundary is segmented based on a grey level model with two thresholds; then, an adapted active contour model approach is applied to the more complicated outer boundary segmentation, with its initialization based on the available inner boundary segmentation. An opacity image, which aims at enhancing important features while reducing spurious structures, is calculated from the CTA images and employed to guide the deformation of the model. In addition, the active contour model is extended by a constraint force that prevents intersections of the inner and outer boundary and keeps the outer boundary at a distance, given by the thrombus thickness, to the inner boundary. Based upon the segmentation results, we can measure the aneurysm size at each centerline point on the centerline orthogonal multiplanar reformatting (MPR) plane. Furthermore, a 3D TAA or AAA model is reconstructed from the set of segmented contours, and the presence of endoleaks is detected and highlighted. The implemented method has been evaluated on nine clinical CTA data sets with variations in anatomy and location of the pathology and has shown promising results.

Segmented Mirror Image Degradation Due to Surface Dust, Alignment and Figure

NASA Technical Reports Server (NTRS)

Schreur, Julian J.

1999-01-01

In 1996 an algorithm was developed to include the effects of surface roughness in the calculation of the point spread function of a telescope mirror. This algorithm has been extended to include the effects of alignment errors and figure errors for the individual elements, and an overall contamination by surface dust. The final algorithm builds an array for a guard-banded pupil function of a mirror that may or may not have a central hole, a central reflecting segment, or an outer ring of segments. The central hole, central reflecting segment, and outer ring may be circular or polygonal, and the outer segments may have trimmed comers. The modeled point spread functions show that x-tilt and y-tilt, or the corresponding R-tilt and theta-tilt for a segment in an outer ring, is readily apparent for maximum wavefront errors of 0.1 lambda. A similar sized piston error is also apparent, but integral wavelength piston errors are not. Severe piston error introduces a focus error of the opposite sign, so piston could be adjusted to compensate for segments with varying focal lengths. Dust affects the image principally by decreasing the Strehl ratio, or peak intensity of the image. For an eight-meter telescope a 25% coverage by dust produced a scattered light intensity of 10(exp -9) of the peak intensity, a level well below detectability.

Segmented inlet nozzle for gas turbine, and methods of installation

DOEpatents

Klompas, Nicholas

1985-01-01

A gas turbine nozzle guide vane assembly is formed of individual arcuate nozzle segments. The arcuate nozzle segments are elastically joined to each other to form a complete ring, with edges abutted to prevent leakage. The resultant nozzle ring is included within the overall gas turbine stationary structure and secured by a mounting arrangement which permits relative radial movement at both the inner and outer mountings. A spline-type outer mounting provides circumferential retention. A complete rigid nozzle ring with freedom to "float" radially results. Specific structures are disclosed for the inner and outer mounting arrangements. A specific tie-rod structure is also disclosed for elastically joining the individual nozzle segments. Also disclosed is a method of assembling the nozzle ring subassembly-by-subassembly into a gas turbine employing temporary jacks.

The localization of guanylyl cyclase-activating proteins in the mammalian retina.

PubMed

Cuenca, N; Lopez, S; Howes, K; Kolb, H

1998-06-01

To explore the distribution of guanylyl cylase-activating proteins 1 and 2 (GCAP1 and GCAP2) in the mammalian retina. Cryostat and vibratome vertical sections and wholemount retinas from mouse, rat, cat, bovine, monkey, and human eyes were prepared for immunocytochemistry and viewing by light and confocal microscopy. In all mammalian retinas investigated, intense GCAP1 immunoreactivity (GCAP1-IR) was seen in cone photoreceptor inner and outer segments, cell bodies, and synaptic regions. Intensity of the GCAP1-IR was strong in inner segments of rods in all species but weaker in outer segments-particularly so in primates and cats. GCAP2 immunoreactivity (GCAP2-IR) was weak in bovine, mouse, and rat cones but was intense in human and monkey cones. In all species except primates, GCAP2 staining was intense in rod inner and outer segments. In primates GCAP2-IR was intense in the rod inner segment but faint in the rod outer segment. A striking difference from the GCAP1 pattern of immunoreactivity was seen with GCAP2 antibodies as far as the inner retina was concerned. GCAP2-IR was evident in certain populations of bipolar, amacrine, and ganglion cells in all species. GCAP1 and GCAP2, which are involved in Ca2+-dependent stimulation and inhibition of photoreceptor guanylyl cyclase, can be detected in mammalian photoreceptor inner and outer segments, consistent with their physiological function. The occurrence of both GCAPs in the synaptic region of the photoreceptors indicates participation of these proteins in pathways other than regulation of phototransduction. The occurrence of GCAP2 in inner retinal neurons is indicative of second-messenger chemical transduction, possibly in metabotropic glutamate, gamma-aminobutyric acid (GABA) receptor, and nitric oxide-activated neural circuits.

Timing Actions to Avoid Refractoriness: A Simple Solution for Streaming Sensory Signals

PubMed Central

Nogueira, Javier; Caputi, Ángel Ariel

2011-01-01

Segmenting self- from allo-generated signals is crucial for active sensory processing. We report a dynamic filter used by South American pulse electric fish to distinguish active electro-sensory signals carried by their own electric discharges from other concomitant electrical stimuli (i.e. communication signals). The filter has a sensory component, consisting of an onset type central electro-sensory neuron, and a motor component, consisting of a change in the fish's discharge rate when allo-generated electrical events occur in temporal proximity to the fish's own discharge. We investigated the sensory component of the filter by in vitro mimicking synaptic inputs occurring during behavioral responses to allo-generated interfering signals. We found that active control of the discharge enhances self-generated over allo-generated responses by forcing allo-generated signals into a central refractory period. This hypothesis was confirmed by field potential recordings in freely discharging fish. Similar sensory-motor mechanisms may also contribute to signal segmentation in other sensory systems. PMID:21789228

Alterations of the outer retina in non-arteritic anterior ischaemic optic neuropathy detected using spectral-domain optical coherence tomography.

PubMed

Ackermann, Philipp; Brachert, Maike; Albrecht, Philipp; Ringelstein, Marius; Finis, David; Geerling, Gerd; Aktas, Orhan; Guthoff, Rainer

2017-07-01

A characteristic disease pattern may be reflected by retinal layer thickness changes in non-arteritic anterior ischaemic optic neuropathy measured using spectraldomain optical coherence tomography. Retinal layer segmentation is enabled by advanced software. In this study, retinal layer thicknesses in acute and chronic non-arteritic anterior ischaemic optic neuropathy were compared. A single-centre cross-sectional analysis was used. A total of 27 patients (20 age-matched healthy eyes) were included: 14 with acute (<7 days) and 13 patients with chronic non-arteritic anterior ischaemic optic neuropathy. Macular volume and 12° peripapillary ring optical coherence tomography scans were used. The peripapillary thicknesses of the following layers were determined by manual segmentation: retinal nerve fibres, ganglion cells + inner plexiform layer, inner nuclear layer + outer plexiform layer, outer nuclear layer + inner segments of the photoreceptors and outer segments of the photoreceptors to Bruch's membrane. Macular retinal layer thicknesses were automatically determined in volume cubes centred on the fovea. Peripapillary retinal swelling in acute nonarteritic anterior ischaemic optic neuropathy was attributable to retinal nerve fibre layer, ganglion cell layer/inner plexiform layer and outer nuclear layer/segments of the photoreceptors thickening. In chronic cases, peripapillary retinal nerve fibre layer, macular ganglion cell layer and inner plexiform layer thinning were observed. In acute non-arteritic anterior ischaemic optic neuropathy, the inner and outer peripapillary retinal layers are affected by thickness changes. In chronic cases, atrophy of the ganglion cells and their axons and dendrites is evident by inner retinal layer thinning. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

System for supporting a bundled tube fuel injector within a combustor

DOE Office of Scientific and Technical Information (OSTI.GOV)

LeBegue, Jeffrey Scott; Melton, Patrick Benedict; Westmoreland, III, James Harold

A combustor includes an end cover having an outer side and an inner side, an outer barrel having a forward end that is adjacent to the inner side of the end cover and an aft end that is axially spaced from the forward end. An inner barrel is at least partially disposed concentrically within the outer barrel and is fixedly connected to the outer barrel. A fluid conduit extends downstream from the end cover. A first bundled tube fuel injector segment is disposed concentrically within the inner barrel. The bundled tube fuel injector segment includes a fuel plenum that ismore » in fluid communication with the fluid conduit and a plurality of parallel tubes that extend axially through the fuel plenum. The bundled tube fuel injector segment is fixedly connected to the inner barrel.« less

Segmented trapped vortex cavity

NASA Technical Reports Server (NTRS)

Grammel, Jr., Leonard Paul (Inventor); Pennekamp, David Lance (Inventor); Winslow, Jr., Ralph Henry (Inventor)

2010-01-01

An annular trapped vortex cavity assembly segment comprising includes a cavity forward wall, a cavity aft wall, and a cavity radially outer wall there between defining a cavity segment therein. A cavity opening extends between the forward and aft walls at a radially inner end of the assembly segment. Radially spaced apart pluralities of air injection first and second holes extend through the forward and aft walls respectively. The segment may include first and second expansion joint features at distal first and second ends respectively of the segment. The segment may include a forward subcomponent including the cavity forward wall attached to an aft subcomponent including the cavity aft wall. The forward and aft subcomponents include forward and aft portions of the cavity radially outer wall respectively. A ring of the segments may be circumferentially disposed about an axis to form an annular segmented vortex cavity assembly.

[Investigation of the sensory organs on antennae of the horseflies Hybomitra bimaculata and Tabanus bovinus (Diptera: Tabanidae) by scanning electron microscope].

PubMed

Ivanov, V P

2007-01-01

Sensory organs on the antennae of the horseflies Hybomitra bimaculata Macq. and Tabanus bovinus Loew are represented by the same morphological types of sensilla. Never differences in the topographical distribution of the sensilla on antennae have been also found, which can be explained by the similarity of ecological and behavioural adaptations of these insects. First and second antennal segments are found to be supplied with tactile hairs and proprioceptors. Other antennal segments bear sensory organs of several morphological types. Short thin olfactory hairs are most numerous among them. They are present on all segments of the antennal flagellum and belong to two morphological types different by the hair length. In the upper parts of the antennal segments from third to seventh several sensilla trichoidea are present, which probably serve as tactile and taste receptors.

Histological techniques for study of photoreceptor orientation.

PubMed

Laties, A M

1969-01-01

An histological method for the study of photoreceptor orientation in primate eyes is described. To preserve photoreceptor orientation it is necessary to protect the fragile rod and cone outer segments to the maximum extent possible from mechanical deformation and from injury by solvent extraction. To prevent mechanical deformation the eyes are freeze-dried and embedded in plastic with or without prior vapor fixation. Solvent extraction from the lipid-rich outer segment is limited by avoidance or restriction of organic solvents. When large segments of primate eyes are so treated, it is possible to section the plastic blocks along the visual axis, polish the block surface, and view photoreceptor orientation by epi-illumination microscopy. In such specimens a differential orientation of photoreceptors exists with the long axis of photoreceptor inner and outer segments in line with incoming light rays.

Wedge edge ceramic combustor tile

DOEpatents

Shaffer, J.E.; Holsapple, A.C.

1997-06-10

A multipiece combustor has a portion thereof being made of a plurality of ceramic segments. Each of the plurality of ceramic segments have an outer surface and an inner surface. Each of the plurality of ceramic segments have a generally cylindrical configuration and including a plurality of joints. The joints define joint portions, a first portion defining a surface being skewed to the outer surface and the inner surface. The joint portions have a second portion defining a surface being skewed to the outer surface and the inner surface. The joint portions further include a shoulder formed intermediate the first portion and the second portion. The joints provide a sealing interlocking joint between corresponding ones of the plurality of ceramic segments. Thus, the multipiece combustor having the plurality of ceramic segment with the plurality of joints reduces the physical size of the individual components and the degradation of the surface of the ceramic components in a tensile stress zone is generally eliminated reducing the possibility of catastrophic failures. 7 figs.

Wedge edge ceramic combustor tile

DOEpatents

Shaffer, James E.; Holsapple, Allan C.

1997-01-01

A multipiece combustor has a portion thereof being made of a plurality of ceramic segments. Each of the plurality of ceramic segments have an outer surface and an inner surface. Each of the plurality of ceramic segments have a generally cylindrical configuration and including a plurality of joints. The joints define joint portions, a first portion defining a surface being skewed to the outer surface and the inner surface. The joint portions have a second portion defining a surface being skewed to the outer surface and the inner surface. The joint portions further include a shoulder formed intermediate the first portion and the second portion. The joints provide a sealing interlocking joint between corresponding ones of the plurality of ceramic segments. Thus, the multipiece combustor having the plurality of ceramic segment with the plurality of joints reduces the physical size of the individual components and the degradation of the surface of the ceramic components in a tensile stress zone is generally eliminated reducing the possibility of catastrophic failures.

Quantification of photoreceptor layer thickness in different macular pathologies using ultrahigh-resolution optical coherence tomography

NASA Astrophysics Data System (ADS)

Drexler, Wolfgang; Hermann, Boris; Unterhuber, Angelika; Sattmann, Harald; Wirtitsch, Matthias; Stur, Michael; Scholda, Christoph; Ergun, Erdem; Anger, Elisabeth; Ko, Tony H.; Schubert, Christian; Ahnelt, Peter K.; Fujimoto, James G.; Fercher, Adolf F.

2004-07-01

In vivo ultrahigh resolution ophthalmic OCT has been performed in more than 300 eyes of 200 patients with several retinal pathologies, demonstrating unprecedented visualization of all major intraretinal layers, in particular the photoreceptor layer. Visualization as well as quantification of the inner and outer segment of the photoreceptor layer especially in the foveal region has been acvhieved. In normal subjects the photoreceptor layer thickness in the center of the fovea is about of 90 μm, approximately equally distributed to the inner and the outer photoreceptor segment. In the parafoveal region this thickness is reduced to ~50 μm (~30 μm for the inner and ~20 μm for the outer segment). This is in good agreement with well known increase of cone outer segments in the central foveal region. Photoreceptor layer impairment in different macular pathologies like macular hole, central serous chorioretinopathy, age related macular degeneration, foveomacular dystrophies, Stargardt dystrophy as well as retinitis pigmentosa has been investigated. Photoreceptor layer loss significantly correlated with visual acuity (R2 = 0.6, p < 0.001) and microperimetry findings for the first time in 22 eyes with Stargardt dystrophy. Visualization and quantification of photoreceptor inner and outer segment using ultrahigh resolution OCT has the potential to improve early ophthalmic diagnosis, contributes to a better understanding of pathogenesis of retinal diseases as well as might have impact in the development and monitoring of novel therapy approaches.

Acupuncture-induced changes of pressure pain threshold are mediated by segmental inhibition--a randomized controlled trial.

PubMed

Baeumler, Petra I; Fleckenstein, Johannes; Benedikt, Franziska; Bader, Julia; Irnich, Dominik

2015-11-01

Our aim was to distinguish between spinal and supraspinal mechanisms in the intact nervous system by comparing homosegmental and heterosegmental effects of electroacupuncture (EA) and manual acupuncture (MA) on sensory perception in healthy volunteers by means of quantitative sensory testing. Seventy-two healthy volunteers were randomly assigned to receive either MA or EA at SP 6, SP 9, GB 39, and ST 36 at the left leg or relaxed for 30 minutes (control group [CG]). Blinded examiners assessed 13 sensory modalities (thermal and mechanical detection and pain thresholds) at the upper arms and lower legs before and after intervention by means of a standardized quantitative sensory testing battery. Change scores of all 13 sensory thresholds were compared between groups. The main outcome measure was the change score of the pressure pain threshold (PPT). There were no baseline differences between groups. Pressure pain threshold change scores at the lower left leg, in the same segment as the needling site, differed significantly (P = 0.008) between the EA (median: 103.01 kPa) and CG groups (median: 0.00 kPa) but not between the MA (median: 0.00 kPa) and CG groups. No further significant change score differences were found between one of the acupuncture groups and the CG. The PPT can be changed by EA. The PPT increase was confined to the segment of needling, which indicates that it is mainly mediated by segmental inhibition in the spinal cord. This underscores the importance of segmental needling and electrical stimulation in clinical practice.

Calcium homeostasis in the outer segments of retinal rods from the tiger salamander.

PubMed Central

Lagnado, L; Cervetto, L; McNaughton, P A

1992-01-01

1. The processes regulating intracellular calcium in the outer segments of salamander rods have been investigated. The main preparation used was the isolated rod loaded with the Ca(2+)-sensitive photoprotein aequorin, from which outer segment membrane current and free [Ca2+]i could be recorded simultaneously. Two other preparations were also used: outer segment membrane current was recorded from intact, isolated rods using a suction pipette, and from detached outer segments using a whole-cell pipette. 2. Measurements of free intracellular [Ca2+] in Ringer solution were obtained from two aequorin-loaded rods. Mean [Ca2+]i in darkness was 0.41 microM, and after a bright flash [Ca2+]i fell to below detectable levels ( < 0.3 microM). No release of intracellular Ca2+ by a bright flash of light could be detected ( < 0.2 microM). 3. Application of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine (IBMX) caused an increase in the size of the light-sensitive current and a rise in [Ca2+]i, but application of IBMX either when the light-sensitive channels had been closed by a bright light or in the absence of external Ca2+ caused no detectable rise in [Ca2+]i. It is concluded that IBMX increases [Ca2+]i by opening light-sensitive channels, and does not release Ca2+ from stores within the outer segment. 4. Removal of external Na+ caused a rise in [Ca2+]i to around 2 microM and completely suppressed the light-sensitive current. 5. The Na(+)-Ca2+, K+ exchange current in aequorin-loaded rods was activated in first-order manner by internal free calcium, with a mean Michaelis constant, KCa, of 1.6 microM. 6. The KCa of the Na(+)-Ca2+, K+ exchange was increased by elevating internal [Na+]. 7. The Michaelis relation between [Ca2+]i and the activity of the Na(+)-Ca2+, K+ exchange was used to calculate the change in [Ca2+]i occurring during the response to a bright light. In aequorin-loaded rods in Ringer solution the mean change in free [Ca2+]i after a bright flash was 0.34 microM. In these rods 10% of the dark current was carried by Ca2+. 8. Most of the calcium entering the outer segment was taken up rapidly and reversibly by buffer systems. The time constant of equilibration between free and rapidly bound Ca2+ was less than 20 ms. No slow component of calcium uptake was detected. 9. Two components of calcium buffering could be distinguished in the outer segments of aequorin-loaded rods.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1282928

Peripheral ionotropic glutamate receptors contribute to Fos expression increase in the spinal cord through antidromic electrical stimulation of sensory nerves.

PubMed

Li, Jia-Heng; He, Pei-Yao; Fan, Dan-Ni; Alemujiang, Dilinapa; Huo, Fu-Quan; Zhao, Yan; Cao, Dong-Yuan

2018-06-21

Previous studies have shown that peripheral ionotropic glutamate receptors are involved in the increase in sensitivity of a cutaneous branch of spinal dorsal ramus (CBDR) through antidromic electrical stimulation (ADES) of another CBDR in the adjacent segment. CBDR in the thoracic segments run parallel to each other and no synaptic contact at the periphery is reported. The present study investigated whether the increased sensitivity of peripheral sensory nerves via ADES of a CBDR induced Fos expression changes in the adjacent segments of the spinal cord. Fos expression increased in the T8 - T12 segments of the spinal cord evoked by ADES of the T10 CBDR in rats. The increased Fos expression in the T11 and T12, but not T8 - T10 spinal cord segments, was significantly blocked by local application of either N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine maleate (MK-801) or non-NMDA receptor antagonist 6,7-dinitroquinoxaline-2,3-dione (DNQX) into the receptive field of T11 CBDR. The results suggest that endogenous glutamate released by ADES of sensory nerve may bind to peripheral ionotropic glutamate receptors and activate adjacent sensory nerve endings to increase the sensitivity of the spinal cord. These data reveal the potential mechanisms of neuron activation in the spinal cord evoked by peripheral sensitization. Copyright © 2018 Elsevier B.V. All rights reserved.

Light induces a rapid and transient increase in inositol-trisphosphate in toad rod outer segments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, J.E.; Blazynski, C.; Cohen, A.I.

1987-08-14

The sub-second time course of changes in the content of (/sup 3/H)inositol-1,4,5-trisphosphate was determined in rod outer segments from very rapidly frozen Bufo retinas that had been incubated with (/sup 3/H)inositol. Rod outer segments were cut off frozen specimens with a cryostat microtome and the water soluble extracts were analyzed. The content of (/sup 3/H)inositol-1,4,5-trisphosphate rose after approximately 250 msec of bright illumination, but returned to the unstimulated level after 1 sec, whether the stimulus remained on or not. That is, there was rapid but transient change in the content of (/sup 3/H)inositol-1,4,5-trisphosphate after the onset of stimulation.

Pulse joining cartridges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

Pulse joining cartridges

DOEpatents

Golovashchenko, Sergey Fedorovich; Bonnen, John Joseph Francis

2016-08-23

A pulsed joining tool includes a tool body that defines a cavity that receives an inner tubular member and an outer tubular member and a pulse joining cartridge. The tubular members are nested together with the cartridge being disposed around the outer tubular member. The cartridge includes a conductor, such as a wire or foil, that extends around the outer tubular member and is insulated to separate a supply segment from a return segment. A source of stored electrical energy is discharged through the conductor to join the tubular members with an electromagnetic force pulse.

Study on a New Combination Method and High Efficiency Outer Rotor Type Permanent Magnet Motors

NASA Astrophysics Data System (ADS)

Enomoto, Yuji; Kitamura, Masashi; Motegi, Yasuaki; Andoh, Takashi; Ochiai, Makoto; Abukawa, Toshimi

The segment stator core, high space factor coil, and high efficiency magnet are indispensable technologies in the development of compact and a high efficiency motors. But adoption of the segment stator core and high space factor coil has not progressed in the field of outer rotor type motors, for the reason that the inner components cannot be laser welded together. Therefore, we have examined a segment stator core combination technology for the purposes of getting a large increase in efficiency and realizing miniaturization. We have also developed a characteristic estimation method which provides the most suitable performance for segment stator core motors.

Leaf seal for gas turbine stator shrouds and a nozzle band

DOEpatents

Burdgick, Steven Sebastian; Sexton, Brendan Francis

2002-01-01

A leaf seal assembly is secured to the trailing edge of a shroud segment for sealing between the shroud segment and the leading edge side wall of a nozzle outer band. The leaf seal includes a circumferentially elongated seal plate biased by a pair of spring clips disposed in a groove along the trailing edge of the shroud segment to maintain the seal plate in engagement with the flange on the leading edge side wall of the nozzle outer band. The leaf seal plate and spring clips receive pins tack-welded to the shroud segment to secure the leaf seal assembly in place.

Structural and functional changes associated with normal and abnormal fundus autofluorescence in patients with retinitis pigmentosa.

PubMed

Greenstein, Vivienne C; Duncker, Tobias; Holopigian, Karen; Carr, Ronald E; Greenberg, Jonathan P; Tsang, Stephen H; Hood, Donald C

2012-02-01

To analyze the structure and visual function of regions bordering the hyperautofluorescent ring/arcs in retinitis pigmentosa. Twenty-one retinitis pigmentosa patients (21 eyes) with rings/arcs and 21 normal individuals (21 eyes) were studied. Visual sensitivity in the central 10° was measured with microperimetry. Retinal structure was evaluated with spectral-domain optical coherence tomography. The distance from the fovea to disruption/loss of the inner outer segment (IS/OS) junction and thicknesses of the total receptor plus retinal pigment epithelial complex and outer segment plus retinal pigment epithelial complex layers were measured. Results were compared with measurements of the distance from the fovea to the inner and outer borders of the ring/arc seen on fundus autofluorescence. Disruption/loss of the inner outer segment junction occurred closer to the inner border of the ring/arc and it was closer to the fovea in eight eyes. For 19 eyes, outer segment plus and receptor plus RPE complex thicknesses were significantly decreased at locations closer to the fovea than the appearance of the inner border of hyperautofluorescence. Mean visual sensitivity was decreased inside, across, and outside the ring/arc by 3.5 ± 3.8, 8.9 ± 4.8, and 17.0 ± 2.4 dB, respectively. Structural and functional changes can occur inside the hyperfluorescent ring/arc in retinitis pigmentosa.

The Properties of Outer Retinal Band Three Investigated With Adaptive-Optics Optical Coherence Tomography.

PubMed

Jonnal, Ravi S; Gorczynska, Iwona; Migacz, Justin V; Azimipour, Mehdi; Zawadzki, Robert J; Werner, John S

2017-09-01

Optical coherence tomography's (OCT) third outer retinal band has been attributed to the zone of interdigitation between RPE cells and cone outer segments. The purpose of this paper is to investigate the structure of this band with adaptive optics (AO)-OCT. Using AO-OCT, images were obtained from two subjects. Axial structure was characterized by measuring band 3 thickness and separation between bands 2 and 3 in segmented cones. Lateral structure was characterized by correlation of band 3 with band 2 and comparison of their power spectra. Band thickness and separation were also measured in a clinical OCT image of one subject. Band 3 thickness ranged from 4.3 to 6.4 μm. Band 2 correlations ranged between 0.35 and 0.41 and power spectra of both bands confirmed peak frequencies that agree with histologic density measurements. In clinical images, band 3 thickness was between 14 and 19 μm. Measurements of AO-OCT of interband distance were lower than our corresponding clinical OCT measurements. Band 3 originates from a structure with axial extent similar to a single surface. Correlation with band 2 suggests an origin within the cone photoreceptor. These two observations indicate that band 3 corresponds predominantly to cone outer segment tips (COST). Conventional OCT may overestimate both the thickness of band 3 and outer segment length.

The Properties of Outer Retinal Band Three Investigated With Adaptive-Optics Optical Coherence Tomography

PubMed Central

Jonnal, Ravi S.; Gorczynska, Iwona; Migacz, Justin V.; Azimipour, Mehdi; Zawadzki, Robert J.; Werner, John S.

2017-01-01

Purpose Optical coherence tomography's (OCT) third outer retinal band has been attributed to the zone of interdigitation between RPE cells and cone outer segments. The purpose of this paper is to investigate the structure of this band with adaptive optics (AO)-OCT. Methods Using AO-OCT, images were obtained from two subjects. Axial structure was characterized by measuring band 3 thickness and separation between bands 2 and 3 in segmented cones. Lateral structure was characterized by correlation of band 3 with band 2 and comparison of their power spectra. Band thickness and separation were also measured in a clinical OCT image of one subject. Results Band 3 thickness ranged from 4.3 to 6.4 μm. Band 2 correlations ranged between 0.35 and 0.41 and power spectra of both bands confirmed peak frequencies that agree with histologic density measurements. In clinical images, band 3 thickness was between 14 and 19 μm. Measurements of AO-OCT of interband distance were lower than our corresponding clinical OCT measurements. Conclusions Band 3 originates from a structure with axial extent similar to a single surface. Correlation with band 2 suggests an origin within the cone photoreceptor. These two observations indicate that band 3 corresponds predominantly to cone outer segment tips (COST). Conventional OCT may overestimate both the thickness of band 3 and outer segment length. PMID:28877320

Anatomical correlates to the bands seen in the outer retina by optical coherence tomography: literature review and model.

PubMed

Spaide, Richard F; Curcio, Christine A

2011-09-01

To evaluate the validity of commonly used anatomical designations for the four hyperreflective outer retinal bands seen in current-generation optical coherence tomography, a scale model of outer retinal morphology was created using published information for direct comparison with optical coherence tomography scans. Articles and books concerning histology of the outer retina from 1900 until 2009 were evaluated, and data were used to create a scale model drawing. Boundaries between outer retinal tissue compartments described by the model were compared with intensity variations of representative spectral-domain optical coherence tomography scans using longitudinal reflectance profiles to determine the region of origin of the hyperreflective outer retinal bands. This analysis showed a high likelihood that the spectral-domain optical coherence tomography bands attributed to the external limiting membrane (the first, innermost band) and to the retinal pigment epithelium (the fourth, outermost band) are correctly attributed. Comparative analysis showed that the second band, often attributed to the boundary between inner and outer segments of the photoreceptors, actually aligns with the ellipsoid portion of the inner segments. The third band corresponded to an ensheathment of the cone outer segments by apical processes of the retinal pigment epithelium in a structure known as the contact cylinder. Anatomical attributions and subsequent pathophysiologic assessments pertaining to the second and third outer retinal hyperreflective bands may not be correct. This analysis has identified testable hypotheses for the actual correlates of the second and third bands. Nonretinal pigment epithelium contributions to the fourth band (e.g., Bruch membrane) remain to be determined.

Early simultaneous fundus autofluorescence and optical coherence tomography features after pars plana vitrectomy for primary rhegmatogenous retinal detachment.

PubMed

Dell'Omo, Roberto; Mura, Marco; Lesnik Oberstein, Sarit Y; Bijl, Heico; Tan, H Stevie

2012-04-01

To describe fundus autofluorescence and optical coherence tomography (OCT) features of the macula after pars plana vitrectomy for rhegmatogenous retinal detachment. Thirty-three eyes of 33 consecutive patients with repaired rhegmatogenous retinal detachment with or without the involvement of the macula were prospectively investigated with simultaneous fundus autofluorescence and OCT imaging using the Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany) within a few weeks after the operation. Fundus autofluorescence imaging of the macula showed lines of increased and decreased autofluorescence in 19 cases (57.6%). On OCT, these lines corresponded to the following abnormalities: outer retinal folds, inner retinal folds, and skip reflectivity abnormalities of the photoreceptor inner segment/outer segment band. Other OCT findings, not related to abnormal lines on fundus autofluorescence, consisted of disruption of photoreceptor inner segment/outer segment band and collection of intraretinal or subretinal fluid. The presence of outer retinal folds significantly related to metamorphopsia but did not relate to poor postoperative visual acuity. Partial-thickness retinal folds occur commonly after vitrectomy for rhegmatogenous retinal detachment repair and may represent an important anatomical substrate for postoperative metamorphopsia. Fundus autofluorescence and OCT are both sensitive techniques for the detection of these abnormalities.

DYF-1 Is Required for Assembly of the Axoneme in Tetrahymena thermophila▿ †

PubMed Central

Dave, Drashti; Wloga, Dorota; Sharma, Neeraj; Gaertig, Jacek

2009-01-01

In most cilia, the axoneme can be subdivided into three segments: proximal (the transition zone), middle (with outer doublet microtubules), and distal (with singlet extensions of outer doublet microtubules). How the functionally distinct segments of the axoneme are assembled and maintained is not well understood. DYF-1 is a highly conserved ciliary protein containing tetratricopeptide repeats. In Caenorhabditis elegans, DYF-1 is specifically needed for assembly of the distal segment (G. Ou, O. E. Blacque, J. J. Snow, M. R. Leroux, and J. M. Scholey. Nature. 436:583-587, 2005). We show that Tetrahymena cells lacking an ortholog of DYF-1, Dyf1p, can assemble only extremely short axoneme remnants that have structural defects of diverse natures, including the absence of central pair and outer doublet microtubules and incomplete or absent B tubules on the outer microtubules. Thus, in Tetrahymena, DYF-1 is needed for either assembly or stability of the entire axoneme. Our observations support the conserved function for DYF-1 in axoneme assembly or stability but also show that the consequences of loss of DYF-1 for axoneme segments are organism specific. PMID:19581442

Rapid hydrogen ion uptake of rod outer segments and rhodopsin solutions on illumination

PubMed Central

Falk, G.; Fatt, P.

1966-01-01

1. Flash illumination of a suspension of frog rod outer segments or rhodopsin solution in contact with a platinum electrode produces a rapidly developing negative displacement of potential of the electrode (with respect to a reversible electrode). 2. The amplitude of the potential change varies inversely with the H+ buffering capacity of the medium. It is inferred that the response is due to an uptake of H+ by the rod outer segments or rhodopsin, with the platinum surface acting as a pH electrode. 3. Determination of the action spectrum shows that the response depends on the absorption of light by rhodopsin. 4. In frog rods one acid-binding group with a pK of about 7·9 is produced for each molecule of rhodopsin bleached, consistent with a rhodopsin concentration in frog rods of 1·7 mM. 5. It is suggested that the time course of the response with rhodopsin solutions reflects the kinetics of the conversion of metarhodopsin I to metarhodopsin II. 6. A slower time course of voltage change observed for suspensions of outer segments is attributable to the time required for the diffusion of H+ buffer out of the rods. PMID:5945249

Turbine stator vane segment having internal cooling circuits

DOEpatents

Jones, Raymond Joseph; Burns, James Lee; Bojappa, Parvangada Ganapathy; Jones, Schotsch Margaret

2003-01-01

A turbine stator vane includes outer and inner walls each having outer and inner chambers and a vane extending between the outer and inner walls. The vane includes first, second, third, fourth and fifth cavities for flowing a cooling medium. The cooling medium enters the outer chamber of the outer wall, flows through an impingement plate for impingement cooling of the outer band wall defining in part the hot gas path and through openings in the first, second and fourth cavities for flow radially inwardly, cooling the vane. The spent cooling medium flows into the inner wall and inner chamber for flow through an impingement plate radially outwardly to cool the inner wall. The spent cooling medium flows through the third cavity for egress from the turbine vane segment from the outer wall. The first, second or third cavities contain inserts having impingement openings for impingement cooling of the vane walls. The fifth cavity provides air cooling for the trailing edge.

Gas turbine row #1 steam cooled vane

DOEpatents

Cunha, Frank J.

2000-01-01

A design for a vane segment having a closed-loop steam cooling system is provided. The vane segment comprises an outer shroud, an inner shroud and an airfoil, each component having a target surface on the inside surface of its walls. A plurality of rectangular waffle structures are provided on the target surface to enhance heat transfer between each component and cooling steam. Channel systems are provided in the shrouds to improve the flow of steam through the shrouds. Insert legs located in cavities in the airfoil are also provided. Each insert leg comprises outer channels located on a perimeter of the leg, each outer channel having an outer wall and impingement holes on the outer wall for producing impingement jets of cooling steam to contact the airfoil's target surface. Each insert leg further comprises a plurality of substantially rectangular-shaped ribs located on the outer wall and a plurality of openings located between outer channels of the leg to minimize cross flow degradation.

To Honor Fechner and Obey Stevens: Relationships between Psychophysical and Neural Nonlinearities

ERIC Educational Resources Information Center

Billock, Vincent A.; Tsou, Brian H.

2011-01-01

G. T. Fechner (1860/1966) famously described two kinds of psychophysics: "Outer psychophysics" captures the black box relationship between sensory inputs and perceptual magnitudes, whereas "inner psychophysics" contains the neural transformations that Fechner's outer psychophysics elided. The relationship between the two has never been clear.…

Distinct functions for IFT140 and IFT20 in opsin transport.

PubMed Central

Crouse, Jacquelin A.; Lopes, Vanda S.; SanAgustin, Jovenal T.; Keady, Brian T.; Williams, David S.; Pazour, Gregory J.

2014-01-01

In the vertebrate retina, light is detected by the outer segments of photoreceptor rods and cones, which are highly modified cilia. Like other cilia, outer segments have no protein synthetic capacity and depend on proteins made in the cell body for their formation and maintenance. The mechanism of transport into the outer segment is not fully understood but intraflagellar transport (IFT) is thought to be a major mechanism for moving protein from the cell body into the cilium. In the case of photoreceptor cells, the high density of receptors and the disk turnover that occurs daily necessitates much higher rates of transport than would be required in other cilia. In this work, we show that the IFT complex A protein IFT140 is required for development and maintenance of outer segments. In earlier work we found that acute deletion of Ift20 caused opsin to accumulate at the Golgi complex. In this work we find that acute deletion of Ift140 does not cause opsin to accumulate at the Golgi complex but rather it accumulates in the plasma membrane of the inner segments. This work is strong support of a model of opsin transport where IFT20 is involved in the movement from the Golgi complex to the base of the cilium. Then, once at the base, the opsin is carried through the connecting cilium by an IFT complex that includes IFT140. PMID:24619649

Molecular determinants of Guanylate Cyclase Activating Protein subcellular distribution in photoreceptor cells of the retina.

PubMed

López-Begines, Santiago; Plana-Bonamaisó, Anna; Méndez, Ana

2018-02-13

Retinal guanylate cyclase (RetGC) and guanylate cyclase activating proteins (GCAPs) play an important role during the light response in photoreceptor cells. Mutations in these proteins are linked to distinct forms of blindness. RetGC and GCAPs exert their role at the ciliary outer segment where phototransduction takes place. We investigated the mechanisms governing GCAP1 and GCAP2 distribution to rod outer segments by expressing selected GCAP1 and GCAP2 mutants as transient transgenes in the rods of GCAP1/2 double knockout mice. We show that precluding GCAP1 direct binding to RetGC (K23D/GCAP1) prevented its distribution to rod outer segments, while preventing GCAP1 activation of RetGC post-binding (W94A/GCAP1) did not. We infer that GCAP1 translocation to the outer segment strongly depends on GCAP1 binding affinity for RetGC, which points to GCAP1 requirement to bind to RetGC to be transported. We gain further insight into the distinctive regulatory steps of GCAP2 distribution, by showing that a phosphomimic at position 201 is sufficient to retain GCAP2 at proximal compartments; and that the bovine equivalent to blindness-causative mutation G157R/GCAP2 results in enhanced phosphorylation in vitro and significant retention at the inner segment in vivo, as likely contributing factors to the pathophysiology.

Cone outer segment and Müller microvilli pericellular matrices provide binding domains for interphotoreceptor retinoid-binding protein (IRBP).

PubMed

Garlipp, Mary Alice; Gonzalez-Fernandez, Federico

2013-08-01

The close packing of vertebrate photoreceptors presents a challenge to the exchange of molecules between the outer segments, retinal pigmented epithelium (RPE), and Müller glia. An extracellular hyaluronan scaffold separates these cells while soluble interphotoreceptor matrix (IPM) proteins traffic visual cycle retinoids, fatty acids, and other molecules between them. In the IPM, retinoids and fatty acids are carried by interphotoreceptor retinoid-binding protein (IRBP). The fact that much of the retina's IRBP can be extracted by saline wash has led to the notion that IRBP does not bind to the retina, but freely distributes itself within the subretinal space. In this study, we challenge this idea by asking if there are specialized IPM domains that bind IRBP, perhaps facilitating its ability to target delivery/uptake of its ligands. Xenopus is an ideal animal model to study the role of the IPM in RPE-photoreceptor interactions. Here, we took advantage of the large size of its photoreceptors, ability to detach the retina in light, sustainability of the retina in short term organ culture, and the availability of recombinant full-length Xenopus IRBP and antisera directed against Xenopus IRBP. We compared the distribution of wash resistant native IRBP, and that of IRBP-Alexa 647 binding in Xenopus retina. IRBP and cone opsin were localized using anti-Xenopus IRBP serum, and monoclonal COS-1 respectively. Cone matrix sheath proteoglycans were localized with wheat germ agglutinin (WGA), and diffuse IPM proteoglycans with peanut agglutinin (PNA). Wholemounts and frozen sections were compared by immunofluorescence from retinas detached under Ringer's followed by additional washes, or detached directly under 4% paraformaldehyde without Ringer's wash. Undetached Lowicryl embedded retinas were subjected to IRBP immunogold electron microscopy (EM). Immunogold labeled a diffuse network of filamentous structures, and a separate distinct flocculant material directly coating the outer segments, filling the rod periciliary ridge, and associated with Müller microvilli. By immunofluorescence, Ringer's wash removed most of the diffuse IRBP, but not that coating the outer segments. IRBP-Alexa 647 bound to the cone outer segments and Müller villi region, and comparably less to rod outer segments. Co-incubation with unlabeled IRBP markedly reduced this binding; ovalbumin-Alexa 647 and Alexa 647 dye alone showed no binding. Our data suggest that the pericellular matrix of the cone outer segments and Müller microvilli provide specialized domains that facilitate IRBP's functions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Rescue of compromised lysosomes enhances degradation of photoreceptor outer segments and reduces lipofuscin-like autofluorescence in retinal pigmented epithelial cells.

PubMed

Guha, Sonia; Liu, Ji; Baltazar, Gabe; Laties, Alan M; Mitchell, Claire H

2014-01-01

Healthful cell maintenance requires the efficient degradative processing and removal of waste material. Retinal pigmented epithelial (RPE) cells have the onerous task of degrading both internal cellular debris generated through autophagy as well as phagocytosed photoreceptor outer segments. We propose that the inadequate processing material with the resulting accumulation of cellular waste contributes to the downstream pathologies characterized as age-related macular degeneration (AMD). The lysosomal enzymes responsible for clearance function optimally over a narrow range of acidic pH values; elevation of lysosomal pH by compounds like chloroquine or A2E can impair degradative enzyme activity and lead to a lipofuscin-like autofluorescence. Restoring acidity to the lysosomes of RPE cells can enhance activity of multiple degradative enzymes and is therefore a logical target in early AMD. We have identified several approaches to reacidify lysosomes of compromised RPE cells; stimulation of beta-adrenergic, A2A adenosine and D5 dopamine receptors each lowers lysosomal pH and improves degradation of outer segments. Activation of the CFTR chloride channel also reacidifies lysosomes and increases degradation. These approaches also restore the lysosomal pH of RPE cells from aged ABCA4(-/-) mice with chronically high levels of A2E, suggesting that functional signaling pathways to reacidify lysosomes are retained in aged cells like those in patients with AMD. Acidic nanoparticles transported to RPE lysosomes also lower pH and improve degradation of outer segments. In summary, the ability of diverse approaches to lower lysosomal pH and enhance outer segment degradation support the proposal that lysosomal acidification can prevent the accumulation of lipofuscin-like material in RPE cells.

Joint segmentation of lumen and outer wall from femoral artery MR images: Towards 3D imaging measurements of peripheral arterial disease.

PubMed

Ukwatta, Eranga; Yuan, Jing; Qiu, Wu; Rajchl, Martin; Chiu, Bernard; Fenster, Aaron

2015-12-01

Three-dimensional (3D) measurements of peripheral arterial disease (PAD) plaque burden extracted from fast black-blood magnetic resonance (MR) images have shown to be more predictive of clinical outcomes than PAD stenosis measurements. To this end, accurate segmentation of the femoral artery lumen and outer wall is required for generating volumetric measurements of PAD plaque burden. Here, we propose a semi-automated algorithm to jointly segment the femoral artery lumen and outer wall surfaces from 3D black-blood MR images, which are reoriented and reconstructed along the medial axis of the femoral artery to obtain improved spatial coherence between slices of the long, thin femoral artery and to reduce computation time. The developed segmentation algorithm enforces two priors in a global optimization manner: the spatial consistency between the adjacent 2D slices and the anatomical region order between the femoral artery lumen and outer wall surfaces. The formulated combinatorial optimization problem for segmentation is solved globally and exactly by means of convex relaxation using a coupled continuous max-flow (CCMF) model, which is a dual formulation to the convex relaxed optimization problem. In addition, the CCMF model directly derives an efficient duality-based algorithm based on the modern multiplier augmented optimization scheme, which has been implemented on a GPU for fast computation. The computed segmentations from the developed algorithm were compared to manual delineations from experts using 20 black-blood MR images. The developed algorithm yielded both high accuracy (Dice similarity coefficients ≥ 87% for both the lumen and outer wall surfaces) and high reproducibility (intra-class correlation coefficient of 0.95 for generating vessel wall area), while outperforming the state-of-the-art method in terms of computational time by a factor of ≈ 20. Copyright © 2015 Elsevier B.V. All rights reserved.

Static length changes of cochlear outer hair cells can tune low-frequency hearing

PubMed Central

Ciganović, Nikola; Warren, Rebecca L.; Keçeli, Batu; Jacob, Stefan

2018-01-01

The cochlea not only transduces sound-induced vibration into neural spikes, it also amplifies weak sound to boost its detection. Actuators of this active process are sensory outer hair cells in the organ of Corti, whereas the inner hair cells transduce the resulting motion into electric signals that propagate via the auditory nerve to the brain. However, how the outer hair cells modulate the stimulus to the inner hair cells remains unclear. Here, we combine theoretical modeling and experimental measurements near the cochlear apex to study the way in which length changes of the outer hair cells deform the organ of Corti. We develop a geometry-based kinematic model of the apical organ of Corti that reproduces salient, yet counter-intuitive features of the organ’s motion. Our analysis further uncovers a mechanism by which a static length change of the outer hair cells can sensitively tune the signal transmitted to the sensory inner hair cells. When the outer hair cells are in an elongated state, stimulation of inner hair cells is largely inhibited, whereas outer hair cell contraction leads to a substantial enhancement of sound-evoked motion near the hair bundles. This novel mechanism for regulating the sensitivity of the hearing organ applies to the low frequencies that are most important for the perception of speech and music. We suggest that the proposed mechanism might underlie frequency discrimination at low auditory frequencies, as well as our ability to selectively attend auditory signals in noisy surroundings. PMID:29351276

Partially segmented deformable mirror

DOEpatents

Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

1991-05-21

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

Partially segmented deformable mirror

DOEpatents

Bliss, Erlan S.; Smith, James R.; Salmon, J. Thaddeus; Monjes, Julio A.

1991-01-01

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

Acute Zonal Cone Photoreceptor Outer Segment Loss.

PubMed

Aleman, Tomas S; Sandhu, Harpal S; Serrano, Leona W; Traband, Anastasia; Lau, Marisa K; Adamus, Grazyna; Avery, Robert A

2017-05-01

The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if multimodal imaging supports an intact retinal pigment epithelium and inner retina but an abnormal photoreceptor outer segment.

Fusion of laser and image sensory data for 3-D modeling of the free navigation space

NASA Technical Reports Server (NTRS)

Mass, M.; Moghaddamzadeh, A.; Bourbakis, N.

1994-01-01

A fusion technique which combines two different types of sensory data for 3-D modeling of a navigation space is presented. The sensory data is generated by a vision camera and a laser scanner. The problem of different resolutions for these sensory data was solved by reduced image resolution, fusion of different data, and use of a fuzzy image segmentation technique.

Patellar segmentation from 3D magnetic resonance images using guided recursive ray-tracing for edge pattern detection

NASA Astrophysics Data System (ADS)

Cheng, Ruida; Jackson, Jennifer N.; McCreedy, Evan S.; Gandler, William; Eijkenboom, J. J. F. A.; van Middelkoop, M.; McAuliffe, Matthew J.; Sheehan, Frances T.

2016-03-01

The paper presents an automatic segmentation methodology for the patellar bone, based on 3D gradient recalled echo and gradient recalled echo with fat suppression magnetic resonance images. Constricted search space outlines are incorporated into recursive ray-tracing to segment the outer cortical bone. A statistical analysis based on the dependence of information in adjacent slices is used to limit the search in each image to between an outer and inner search region. A section based recursive ray-tracing mechanism is used to skip inner noise regions and detect the edge boundary. The proposed method achieves higher segmentation accuracy (0.23mm) than the current state-of-the-art methods with the average dice similarity coefficient of 96.0% (SD 1.3%) agreement between the auto-segmentation and ground truth surfaces.

Cell and current collector felt arrangement for solid oxide electrochemical cell combinations

DOEpatents

Reichner, Philip

1988-01-01

A solid electrolyte electrochemical cell combination 1 is made, comprising an annular, axially elongated, inner electrode 2 containing at least one interior gas feed conduit 3; annular solid electrolyte segments 4 around and covering portions of the inner electrode; annular outer electrode segments 6 around and covering portions of the electrolyte segments; electronically conducting, non-porous, interconnection material 5 disposed between electrolyte segments and in contact with the inner electrode, and electronically conducting, porous, metal fiber current collector felts 7 disposed on top of the non-porous interconnect material and outer electrode segments, where both the non-porous interconnect material and the porous metal felts are disposed circumferentially about the cell, transversely to the axial length of the cell and the inner electrode is continuous for the entire axial length of the cell combination.

Localization of antibody binding sites in ultrathin sections of unembedded frog retinal tissue.

PubMed

Pease, D C; Nir, I; Clark, V; Hall, M

1983-01-01

Much ultrastructural detail is retained in tissue fixed only with aldehydes and subsequently air-dried after suspension in a polyvinyl acetate emulsion. The latter provides an external support only, but permits ultrathin sectioning; thus, an exposure of intracellular contents for potential immunocytochemical reactions is achieved. Sections of unembedded frog retina so prepared have been studied with success. The tissue was incubated first with a rabbit antiserum prepared against gradient purified bovine rod outer segments. Following incubation, reacted sites were labeled with ferritin-conjugated goat anti-rabbit IgG and stained with phosphotungstic acid. Intense labeling of the rod outer segments was clearly achieved, whereas the cone outer segments were without label. Other parts of the retina, including the ellipsoid region of both rods and cones, were also without significant label. These regions provided an intrinsic control for the specificity of the antiserum and established the validity of the general technique.

A heterozygous putative null mutation in ROM1 without a mutation in peripherin/RDS in a family with retinitis pigmentosa

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sakuma, Hitoshi; Inana, G.; Murakami, Akira

1995-05-20

ROM1 is a 351-amino-acid, 37-kDa outer segment membrane protein of rod photoreceptors. ROM1 is related to peripherin/RDS, another outer segment membrane protein found in both rods and cones. The precise function of ROM1 or peripherin/RDS is not known, but they have been suggested to play important roles in the function and/or structure of the rod photoreceptor outer segment disks. A recent report implicated ROM1 in disease by suggesting that RP can be caused by a heterozygous null mutation in ROM1 but only in combination with another heterozygous mutation in peripherin/RDS. Screening of the ROM1 gene using polymerase chain reaction amplification,more » denaturing gradient gel electrophoresis, and direct DNA sequencing identified the same heterozygous putative null mutation in a family with RP.« less

Uncoordinated (UNC)119: coordinating the trafficking of myristoylated proteins.

PubMed

Constantine, Ryan; Zhang, Houbin; Gerstner, Cecilia D; Frederick, Jeanne M; Baehr, Wolfgang

2012-12-15

The mechanism by which myristoylated proteins are targeted to specific subcellular membrane compartments is poorly understood. Two novel acyl-binding proteins, UNC119A and UNC119B, have been shown recently to function as chaperones/co-factors in the transport of myristoylated G protein α-subunits and src-type tyrosine kinases. UNC119 polypeptides feature an immunoglobulin-like β-sandwich fold that forms a hydrophobic pocket capable of binding lauroyl (C12) and myristoyl (C14) side chains. UNC119A in rod photoreceptors facilitates the transfer of transducin α subunits (Tα) from inner segment to outer segment membranes by forming an intermediate diffusible UNC119-Tα complex. Similar complexes are formed in other sensory neurons, as the G proteins ODR-3 and GPA-13 in Caenorhabditis elegans unc-119 mutants traffic inappropriately. UNC119B knockdown in IMCD3 cells prevents trafficking ofmyristoylated nephrocystin-3 (NPHP3), a protein associated with nephronophthisis, to cilia. Further, UNC119A was shown to transport myristoylated src-type tyrosine kinases to cell membranes and to affect T-cell receptor (TCR) and interleukin-5 receptor (IL-5R) activities. These interactions establish UNC119 polypeptides as novel lipid-binding chaperones with specificity for a diverse subset of myristoylated proteins. Copyright © 2012 Elsevier Ltd. All rights reserved.

Uncoordinated (UNC)119: Coordinating the Trafficking of Myristoylated Proteins

PubMed Central

Constantine, Ryan; Zhang, Houbin; Gerstner, Cecilia D.; Frederick, Jeanne M.; Baehr, Wolfgang

2012-01-01

The mechanism by which myristoylated proteins are targeted to specific subcellular membrane compartments is poorly understood. Two novel acyl-binding proteins, UNC119A and UNC119B, have been shown recently to function as chaperones/co-factors in the transport of myristoylated G protein α-subunits and src-type tyrosine kinases. UNC119 polypeptides feature an immunoglobulin-like β-sandwich fold that forms a hydrophobic pocket capable of binding lauroyl (C12) and myristoyl (C14) side chains. UNC119A in rod photoreceptors facilitates the transfer of transducin α subunits (Tα) from inner segment to outer segment membranes by forming an intermediate diffusible UNC119-Tα complex. Similar complexes are formed in other sensory neurons, as the G proteins ODR-3 and GPA-13 in C. elegans unc-119 mutants traffic inappropriately. UNC119B knockdown in IMCD3 cells prevents trafficking of myristoylated nephrocystin-3 (NPHP3), a protein associated with nephronophthisis, to cilia. Further, UNC119A was shown to transpot myristoylated src-type tyrosine kinases to cell membranes and to affect T-cell receptor (TCR) and interleukin-5 receptor (IL-5R) activities. These interactions establish UNC119 polypeptides as novel lipid-binding chaperones with specificity for a diverse subset of myristoylated proteins. PMID:23000199

HYPERAUTOFLUORESCENT RING IN AUTOIMMUNE RETINOPATHY

PubMed Central

LIMA, LUIZ H.; GREENBERG, JONATHAN P.; GREENSTEIN, VIVIENNE C.; SMITH, R. THEODORE; SALLUM, JULIANA M. F.; THIRKILL, CHARLES; YANNUZZI, LAWRENCE A.; TSANG, STEPHEN H.

2015-01-01

Purpose To report the presence of a hyperautofluorescent ring and corresponding spectral-domain optical coherence tomography (SD-OCT) features seen in patients with autoimmune retinopathy. Methods All eyes were evaluated by funduscopic examination, full-fleld electroretinography, fundus autofluorescence, and SD-OCT. Further confirmation of the diagnosis was obtained with immunoblot and immunohistochemistry testing of the patient’s serum. Humphrey visual fields and microperimetry were also performed. Results Funduscopic examination showed atrophic retinal pigment epithelium (RPE) associated with retinal artery narrowing but without pigment deposits. The scotopic and photopic full-field electroretinograms were nondetectable in three patients and showed a cone–rod pattern of dysfunction in one patient. Fundus autofluorescence revealed a hyperautofluorescent ring in the parafoveal region, and the corresponding SD-OCT demonstrated loss of the photoreceptor inner segment–outer segment junction with thinning of the outer nuclear layer from the region of the hyperautofluorescent ring toward the retinal periphery. The retinal layers were generally intact within the hyperautofluorescent ring, although the inner segment–outer segment junction was disrupted, and the outer nuclear layer and photoreceptor outer segment layer were thinned. Conclusion This case series revealed the structure of the hyperautofluorescent ring in autoimmune retinopathy using SD-OCT. Fundus autofluorescence and SD-OCT may aid in the diagnosis of autoimmune retinopathy and may serve as a tool to monitor its progression. PMID:22218149

"FruitZotic": A Sensory Approach to Introducing Preschoolers to Fresh Exotic Fruits at Head Start Locations in Western Massachusetts

ERIC Educational Resources Information Center

Kannan, Srimathi; Smith, Rebecca; Foley, Christine; Del Sole, Sarah; White, Alissa; Sheldon, Lisa A.; Mietlcki-Floyd, Shirley; Severin, Suzanne

2011-01-01

FruitZotic incorporated fruit stories (exotic-fruits-literacy), a "See, Smell, Hear, Touch and Taste" (sensory) segment and a question-prompted discussion. Three take-home components incorporating the exotic fruits were: Coloring Activity, Recipes, and Fact Sheets. Sensory based nutrition education can increase familiarity with exotic…

Phagocytosis of photoreceptor outer segments by transplanted human neural stem cells as a neuroprotective mechanism in retinal degeneration.

PubMed

Cuenca, Nicolás; Fernández-Sánchez, Laura; McGill, Trevor J; Lu, Bin; Wang, Shaomei; Lund, Raymond; Huhn, Stephen; Capela, Alexandra

2013-10-15

Transplantation of human central nervous system stem cells (HuCNS-SC) into the subretinal space of Royal College of Surgeons (RCS) rats preserves photoreceptors and visual function. To explore possible mechanism(s) of action underlying this neuroprotective effect, we performed a detailed morphologic and ultrastructure analysis of HuCNS-SC transplanted retinas. The HuCNS-SC were transplanted into the subretinal space of RCS rats. Histologic examination of the transplanted retinas was performed by light and electron microscopy. Areas of the retina adjacent to HuCNS-SC graft (treated regions) were analyzed and compared to control sections obtained from the same retina, but distant from the transplant site (untreated regions). The HuCNS-SC were detected as a layer of STEM 121 immunopositive cells in the subretinal space. In treated regions, preserved photoreceptor nuclei, as well as inner and outer segments were identified readily. In contrast, classic signs of degeneration were observed in the untreated regions. Interestingly, detailed ultrastructure analysis revealed a striking preservation of the photoreceptor-bipolar-horizontal cell synaptic contacts in the outer plexiform layer (OPL) of treated areas, in stark contrast with untreated areas. Finally, the presence of phagosomes and vesicles exhibiting the lamellar structure of outer segments also was detected within the cytosol of HuCNS-SC, indicating that these cells have phagocytic capacity in vivo. This study reveals the novel finding that preservation of specialized synaptic contacts between photoreceptors and second order neurons, as well as phagocytosis of photoreceptor outer segments, are potential mechanism(s) of HuCNS-SC transplantation, mediating functional rescue in retinal degeneration.

Omnidirectional wheel

NASA Technical Reports Server (NTRS)

Blumrich, J. F. (Inventor)

1974-01-01

The apparatus consists of a wheel having a hub with radially disposed spokes which are provided with a plurality of circumferential rim segments. These rim segments carry, between the spokes, rim elements which are rigid relative to their outer support surfaces, and defined in their outer contour to form a part of the circle forming the wheel diameter. The rim segments have provided for each of the rim elements an independent drive means selectively operable when the element is in ground contact to rotatably drive the rim element in a direction of movement perpendicularly lateral to the normal plane of rotation and movement of the wheel. This affords the wheel omnidirectional movement.

Inhibition or Stimulation of Autophagy Affects Early Formation of Lipofuscin-Like Autofluorescence in the Retinal Pigment Epithelium Cell

PubMed Central

Lei, Lei; Tzekov, Radouil; Li, Huapeng; McDowell, J. Hugh; Gao, Guangping; Smith, W. Clay; Tang, Shibo; Kaushal, Shalesh

2017-01-01

The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is dependent on the effectiveness of photoreceptor outer segment material degradation. This study explored the role of autophagy in the fate of RPE lipofuscin degradation. After seven days of feeding with either native or modified rod outer segments, ARPE-19 cells were treated with enhancers or inhibitors of autophagy and the autofluorescence was detected by fluorescence-activated cell sorting. Supplementation with different types of rod outer segments increased lipofuscin-like autofluorescence (LLAF) after the inhibition of autophagy, while the induction of autophagy (e.g., application of rapamycin) decreased LLAF. The effects of autophagy induction were further confirmed by Western blotting, which showed the conversion of LC3-I to LC3-II, and by immunofluorescence microscopy, which detected the lysosomal activity of the autophagy inducers. We also monitored LLAF after the application of several autophagy inhibitors by RNA-interference and confocal microscopy. The results showed that, in general, the inhibition of the autophagy-related proteins resulted in an increase in LLAF when cells were fed with rod outer segments, which further confirms the effect of autophagy in the fate of RPE lipofuscin degradation. These results emphasize the complex role of autophagy in modulating RPE autofluorescence and confirm the possibility of the pharmacological clearance of RPE lipofuscin by small molecules. PMID:28353645

Transient spectral domain optical coherence tomography findings in classic MEWDS: a case report.

PubMed

Lavigne, Luciana Castro; Isaac, David Leonardo Cruvinel; Duarte Júnior, José Osório; Avila, Marcos Pereira de

2014-01-01

The purpose of this study was to describe a patient with multiple evanescent white dot syndrome (MEWDS) who presented with classic retinal findings and transient changes in outer retinal anatomy. A 20-year-old man presented with mild blurred vision in the left eye, reporting flu-like symptoms 1 week before the visual symptoms started. Fundus examination of the left eye revealed foveal granularity and multiple scattered spots deep to the retina in the posterior pole. Fluorescein angiography and indocyanine green angiography showed typical MEWDS findings. Spectral Domain Optical Coherence Tomography has shown transient changes in outer retinal anatomy with disappearance of inner segment-outer segment junction and mild attenuation of external limiting membrane. Six months later, Spectral Domain Optical Coherence Tomography has shown complete resolution with recovery of normal outer retinal aspect.

The effect of hyperbaric oxygen treatment on early regeneration of sensory axons after nerve crush in the rat.

PubMed

Bajrović, Fajko F; Sketelj, Janez; Jug, Marko; Gril, Iztok; Mekjavić, Igor B

2002-09-01

Abstract The effect of hyperbaric oxygen treatment (HBO) on sensory axon regeneration was examined in the rat. The sciatic nerve was crushed in both legs. In addition, the distal stump of the sural nerve on one side was made acellular and its blood perfusion was compromised by freezing and thawing. Two experimental groups received hyperbaric exposures (2.5 ATA) to either compressed air (pO2 = 0.5 ATA) or 100% oxygen (pO2 = 2.5 ATA) 90 minutes per day for 6 days. Sensory axon regeneration in the sural nerve was thereafter assessed by the nerve pinch test and immunohistochemical reaction to neurofilament. HBO treatment increased the distances reached by the fastest regenerating sensory axons by about 15% in the distal nerve segments with preserved and with compromised blood perfusion. There was no significant difference between the rats treated with different oxygen tensions. The total number of regenerated axons in the distal sural nerve segments after a simple crush injury was not affected, whereas in the nerve segments with compromised blood perfusion treated by the higher pO2, the axon number was about 30% lower than that in the control group. It is concluded that the beneficial effect of HBO on sensory axon regeneration is not dose-dependent between 0.5 and 2.5 ATA pO2. Although the exposure to 2.5 ATA of pO2 moderately enhanced early regeneration of the fastest sensory axons, it decreased the number of regenerating axons in the injured nerves with compromised blood perfusion of the distal nerve stump.

Zone heated diesel particulate filter electrical connection

DOEpatents

Gonze, Eugene V.; Paratore, Jr., Michael J.

2010-03-30

An electrical connection system for a particulate filter is provided. The system includes: a particulate filter (PF) disposed within an outer shell wherein the PF is segmented into a plurality of heating zones; an outer mat disposed between the particulate filter and the outer shell; an electrical connector coupled to the outer shell of the PF; and a plurality of printed circuit connections that extend along the outer surface of the PF from the electrical connector to the plurality of heating zones.

Acute Zonal Cone Photoreceptor Outer Segment Loss

PubMed Central

Sandhu, Harpal S.; Serrano, Leona W.; Traband, Anastasia; Lau, Marisa K.; Adamus, Grazyna; Avery, Robert A.

2017-01-01

Importance The diagnostic path presented narrows down the cause of acute vision loss to the cone photoreceptor outer segment and will refocus the search for the cause of similar currently idiopathic conditions. Objective To describe the structural and functional associations found in a patient with acute zonal occult photoreceptor loss. Design, Setting, and Participants A case report of an adolescent boy with acute visual field loss despite a normal fundus examination performed at a university teaching hospital. Main Outcomes and Measures Results of a complete ophthalmic examination, full-field flash electroretinography (ERG) and multifocal ERG, light-adapted achromatic and 2-color dark-adapted perimetry, and microperimetry. Imaging was performed with spectral-domain optical coherence tomography (SD-OCT), near-infrared (NIR) and short-wavelength (SW) fundus autofluorescence (FAF), and NIR reflectance (REF). Results The patient was evaluated within a week of the onset of a scotoma in the nasal field of his left eye. Visual acuity was 20/20 OU, and color vision was normal in both eyes. Results of the fundus examination and of SW-FAF and NIR-FAF imaging were normal in both eyes, whereas NIR-REF imaging showed a region of hyporeflectance temporal to the fovea that corresponded with a dense relative scotoma noted on light-adapted static perimetry in the left eye. Loss in the photoreceptor outer segment detected by SD-OCT co-localized with an area of dense cone dysfunction detected on light-adapted perimetry and multifocal ERG but with near-normal rod-mediated vision according to results of 2-color dark-adapted perimetry. Full-field flash ERG findings were normal in both eyes. The outer nuclear layer and inner retinal thicknesses were normal. Conclusions and Relevance Localized, isolated cone dysfunction may represent the earliest photoreceptor abnormality or a distinct entity within the acute zonal occult outer retinopathy complex. Acute zonal occult outer retinopathy should be considered in patients with acute vision loss and abnormalities on NIR-REF imaging, especially if multimodal imaging supports an intact retinal pigment epithelium and inner retina but an abnormal photoreceptor outer segment. PMID:28384671

Form, shape and function: segmented blood flow in the choriocapillaris

PubMed Central

Zouache, M. A.; Eames, I.; Klettner, C. A.; Luthert, P. J.

2016-01-01

The development of fluid transport systems was a key event in the evolution of animals and plants. While within vertebrates branched geometries predominate, the choriocapillaris, which is the microvascular bed that is responsible for the maintenance of the outer retina, has evolved a planar topology. Here we examine the flow and mass transfer properties associated with this unusual geometry. We show that as a result of the form of the choriocapillaris, the blood flow is decomposed into a tessellation of functional vascular segments of various shapes delineated by separation surfaces across which there is no flow, and in the vicinity of which the transport of passive substances is diffusion-limited. The shape of each functional segment is determined by the distribution of arterioles and venules and their respective relative flow rates. We also show that, remarkably, the mass exchange with the outer retina is a function of the shape of each functional segment. In addition to introducing a novel framework in which the structure and function of the metabolite delivery system to the outer retina may be investigated in health and disease, the present work provides a general characterisation of the flow and transfers in multipole Hele-Shaw configurations. PMID:27779198

Segmented annular combustor

DOEpatents

Reider, Samuel B.

1979-01-01

An industrial gas turbine engine includes an inclined annular combustor made up of a plurality of support segments each including inner and outer walls of trapezoidally configured planar configuration extents and including side flanges thereon interconnected by means of air cooled connector bolt assemblies to form a continuous annular combustion chamber therebetween and wherein an air fuel mixing chamber is formed at one end of the support segments including means for directing and mixing fuel within a plenum and a perforated header plate for directing streams of air and fuel mixture into the combustion chamber; each of the outer and inner walls of each of the support segments having a ribbed lattice with tracks slidably supporting porous laminated replaceable panels and including pores therein for distributing combustion air into the combustion chamber while cooling the inner surface of each of the panels by transpiration cooling thereof.

Directional sensitivity of the retina: A layered scattering model of outer-segment photoreceptor pigments

PubMed Central

Vohnsen, Brian

2014-01-01

Photoreceptor outer segments have been modeled as stacked arrays of discs or membrane infoldings containing visual pigments with light-induced dipole moments. Waveguiding has been excluded so fields diffract beyond the physical boundaries of each photoreceptor cell. Optical reciprocity is used to argue for identical radiative and light gathering properties of pigments to model vision. Two models have been introduced: one a macroscopic model that assumes a uniform pigment density across each layer and another microscopic model that includes the spatial location of each pigment molecule within each layer. Both models result in highly similar directionality at the pupil plane which proves to be insensitive to the exact details of the outer-segment packing being predominantly determined by the first and last contributing layers as set by the fraction of bleaching. The versatility of the microscopic model is demonstrated with an array of examples that includes the Stiles-Crawford effect, visibility of a focused beam of light and the role of defocus. PMID:24877016

Photoreceptor Outer Segment-like Structures in Long-Term 3D Retinas from Human Pluripotent Stem Cells.

PubMed

Wahlin, Karl J; Maruotti, Julien A; Sripathi, Srinivasa R; Ball, John; Angueyra, Juan M; Kim, Catherine; Grebe, Rhonda; Li, Wei; Jones, Bryan W; Zack, Donald J

2017-04-10

The retinal degenerative diseases, which together constitute a leading cause of hereditary blindness worldwide, are largely untreatable. Development of reliable methods to culture complex retinal tissues from human pluripotent stem cells (hPSCs) could offer a means to study human retinal development, provide a platform to investigate the mechanisms of retinal degeneration and screen for neuroprotective compounds, and provide the basis for cell-based therapeutic strategies. In this study, we describe an in vitro method by which hPSCs can be differentiated into 3D retinas with at least some important features reminiscent of a mature retina, including exuberant outgrowth of outer segment-like structures and synaptic ribbons, photoreceptor neurotransmitter expression, and membrane conductances and synaptic vesicle release properties consistent with possible photoreceptor synaptic function. The advanced outer segment-like structures reported here support the notion that 3D retina cups could serve as a model for studying mature photoreceptor development and allow for more robust modeling of retinal degenerative disease in vitro.

Influence of bacterial toxins on the GTPase activity of transducin from bovine retinal rod outer segments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rybin, V.O.; Gureeva, A.A.

1986-05-10

The action of cholera toxin, capable of ADP-ribosylation of the activator N/sub s/ protein, and pertussis toxin, capable of ADP-ribosylation of the inhibitor N/sub i/ protein of the adenylate cyclase complex, on transducin, the GTP-binding protein of the rod outer segments of the retina, was investigated. It was shown that under the action of pertussis and cholera toxins, the GTPase activity of transducin is inhibited. Pertussin toxin inhibits the GTPase of native retinal rod outer segments by 30-40%, while GTPase of homogeneous transducin produces a 70-80% inhibition. The action of toxins on transducin depends on the presence and nature ofmore » the guanylic nucleotide with which incubation is performed. On the basis of the data obtained it is suggested that pertussis toxin interacts with pretransducin and with the transducin-GDP complex, while cholera toxin ADP-ribosylates the transducin-GTP complex and does not act on transducin lacking GTP.« less

Fgf10 is required for specification of non-sensory regions of the cochlear epithelium

PubMed Central

Urness, Lisa D.; Wang, Xiaofen; Shibata, Shumei; Ohyama, Takahiro; Mansour, Suzanne L.

2015-01-01

The vertebrate inner ear is a morphologically complex sensory organ comprised of two compartments, the dorsal vestibular apparatus and the ventral cochlear duct, required for motion and sound detection, respectively. Fgf10, in addition to Fgf3, is necessary for the earliest stage of otic placode induction, but continued expression of Fgf10 in the developing otic epithelium, including the prosensory domain and later in Kolliker’s organ, suggests additional roles for this gene during morphogenesis of the labyrinth. While loss of Fgf10 was implicated previously in semicircular canal agenesis, we show that Fgf10−/+ embryos also exhibit a reduction or absence of the posterior semicircular canal, revealing a dosage-sensitive requirement for FGF10 in vestibular development. In addition, we show that Fgf10−/− embryos have previously unappreciated defects of cochlear morphogenesis, including a somewhat shortened duct, and, surprisingly, a substantially narrower duct. The mutant cochlear epithelium lacks Reissner’s membrane and a large portion of the outer sulcus--two non-contiguous, non-sensory domains. Marker gene analyses revealed effects on Reissner’s membrane as early as E12.5–E13.5 and on the outer sulcus by E15.5, stages when Fgf10 is expressed in close proximity to Fgfr2b, but these effects were not accompanied by changes in epithelial cell proliferation or death. These data indicate a dual role for Fgf10 in cochlear development: to regulate outgrowth of the duct and subsequently as a bidirectional signal that sequentially specifies Reissner’s membrane and outer sulcus non-sensory domains. These findings may help to explain the hearing loss sometimes observed in LADD syndrome subjects with FGF10 mutations. PMID:25624266

Inner Segment Remodeling and Mitochondrial Translocation in Cone Photoreceptors in Age-Related Macular Degeneration With Outer Retinal Tubulation.

PubMed

Litts, Katie M; Messinger, Jeffrey D; Freund, K Bailey; Zhang, Yuhua; Curcio, Christine A

2015-04-01

To quantify impressions of mitochondrial translocation in degenerating cones and to determine the nature of accumulated material in the subretinal space with apparent inner segment (IS)-like features by examining cone IS ultrastructure. Human donor eyes with advanced age-related macular degeneration (AMD) were screened for outer retinal tubulation (ORT) in macula-wide, high-resolution digital sections. Degenerating cones inside ORT (ORT cones) and outside ORT (non-ORT cones) from AMD eyes and unaffected cones in age-matched control eyes were imaged using transmission electron microscopy. The distances of mitochondria to the external limiting membrane (ELM), cone IS length, and cone IS width at the ELM were measured. Outer retinal tubulation and non-ORT cones lose outer segments (OS), followed by shortening of IS and mitochondria. In non-ORT cones, IS broaden. Outer retinal tubulation and non-ORT cone IS myoids become undetectable due to mitochondria redistribution toward the nucleus. Some ORT cones were found lacking IS and containing mitochondria in the outer fiber (between soma and ELM). Unlike long, thin IS mitochondria in control cones, ORT and non-ORT IS mitochondria are ovoid or reniform. Shed IS, some containing mitochondria, were found in the subretinal space. In AMD, macula cones exhibit loss of detectable myoid due to IS shortening in addition to OS loss, as described. Mitochondria shrink and translocate toward the nucleus. As reflectivity sources, translocating mitochondria may be detectable using in vivo imaging to monitor photoreceptor degeneration in retinal disorders. These results improve the knowledge basis for interpreting high-resolution clinical retinal imaging.

The sensory dorsal organs of crustaceans.

PubMed

Lerosey-Aubril, Rudy; Meyer, Roland

2013-05-01

The cuticle of crustaceans bears numerous organs, of which the functions of many are unknown. One of these, the sensory dorsal organ (SDO), is present in a wide diversity of taxa. Here we critically review the variability, ultrastructure, distribution, and possible function of this enigmatic cuticular organ. Previous data are complemented by new observations on larvae and adults of various malacostracans. The SDO is composed of four sensors arranged as the corners of a square, the centre of which is occupied by a gland. Pores or pegs surrounding this central complex may also form part of the organ. The arrangement and the external aspect of the five main elements varies greatly, but this apparently has little impact on their ultrastructural organisation. The sensors and the gland are associated with a particularly thin cuticle. Each sensor contains four outer dendritic segments and the central gland is made of a single large cell. It is not yet known what this large cell secretes. The SDO is innervated from the tritocerebrum and therefore belongs to the third cephalic segment. A similar organ, here called the posterior SDO, has been repeatedly observed more posteriorly on the carapace. It resembles the SDO but has a greater number of sensors (usually six, but up to ten) apparently associated with only two outer dendritic segments. The SDO and the posterior SDO are known in the Eumalacostraca, the Hoplocarida, and the Phyllocarida. Some branchiopods also possess a 'dorsal organ' resembling both the SDO and the ion-transporting organ more typical of this group. This may indicate a common origin for these two functionally distinct groups of organs. New observations on the posterior SDO support the hypothesis that the SDO and the posterior SDO are homologous to the lattice organ complexes of the costracans. However, the relationship between the SDO and the dorsal cephalic hump of calanoid copepods remains unclear. No correlation can be demonstrated between the presence of a SDO and a particular ecological or biological trait. In fossils, the most convincing examples of SDO-like organs are found in some Late Cambrian arthropods from the Alum Shale of southern Sweden. They suggest that related organs might have been present in non-crustacean Cambrian arthropods. The distribution of the SDO and posterior SDO in extant and fossil crustaceans strongly suggests that these organs originated early in the history of the group, and are crucial to the functioning of these organisms. However, except for knowing that the sensors are chemoreceptors and that in a given organ a functional relationship probably exists between them and the gland, little is known about this function. The description of a SDO in freshwater carideans, which can be easily reared in a laboratory, opens the way for behavioural and physiological experiments to be undertaken that could prove crucial for the determination of this function. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

Retinal photoreceptors and visual pigments in Boa constrictor imperator.

PubMed

Sillman, A J; Johnson, J L; Loew, E R

2001-09-01

The photoreceptors of Boa constrictor, a boid snake of the subfamily Boinae, were examined with scanning electron microscopy and microspectrophotometry. The retina of B. constrictor is duplex but highly dominated by rods, cones comprising 11% of the photoreceptor population. The rather tightly packed rods have relatively long outer segments with proximal ends that are somewhat tapered. There are two morphologically distinct, single cones. The most common cone by far has a large inner segment and a relatively stout outer segment. The second cone, seen only infrequently, has a substantially smaller inner segment and a finer outer segment. The visual pigments of B. constrictor are virtually identical to those of the pythonine boid, Python regius. Three different visual pigments are present, all based on vitamin A(1.) The visual pigment of the rods has a wavelength of peak absorbance (lambda(max)) at 495 +/- 2 nm. The visual pigment of the more common, large cone has a lambda(max) at 549 +/- 1 nm. The small, rare cone contains a visual pigment with lambda(max) at 357 +/- 2 nm, providing the snake with sensitivity in the ultraviolet. We suggest that B. constrictor might employ UV sensitivity to locate conspecifics and/or to improve hunting efficiency. The data indicate that wavelength discrimination above 430 nm would not be possible without some input from the rods. Copyright 2001 Wiley-Liss, Inc.

Sensory Alterations in Patients with Isolated Idiopathic Dystonia: An Exploratory Quantitative Sensory Testing Analysis.

PubMed

Paracka, Lejla; Wegner, Florian; Blahak, Christian; Abdallat, Mahmoud; Saryyeva, Assel; Dressler, Dirk; Karst, Matthias; Krauss, Joachim K

2017-01-01

Abnormalities in the somatosensory system are increasingly being recognized in patients with dystonia. The aim of this study was to investigate whether sensory abnormalities are confined to the dystonic body segments or whether there is a wider involvement in patients with idiopathic dystonia. For this purpose, we recruited 20 patients, 8 had generalized, 5 had segmental dystonia with upper extremity involvement, and 7 had cervical dystonia. In total, there were 13 patients with upper extremity involvement. We used Quantitative Sensory Testing (QST) at the back of the hand in all patients and at the shoulder in patients with cervical dystonia. The main finding on the hand QST was impaired cold detection threshold (CDT), dynamic mechanical allodynia (DMA), and thermal sensory limen (TSL). The alterations were present on both hands, but more pronounced on the side more affected with dystonia. Patients with cervical dystonia showed a reduced CDT and hot detection threshold (HDT), enhanced TSL and DMA at the back of the hand, whereas the shoulder QST only revealed increased cold pain threshold and DMA. In summary, QST clearly shows distinct sensory abnormalities in patients with idiopathic dystonia, which may also manifest in body regions without evident dystonia. Further studies with larger groups of dystonia patients are needed to prove the consistency of these findings.

Use of border information in the classification of mammographic masses

NASA Astrophysics Data System (ADS)

Varela, C.; Timp, S.; Karssemeijer, N.

2006-01-01

We are developing a new method to characterize the margin of a mammographic mass lesion to improve the classification of benign and malignant masses. Towards this goal, we designed features that measure the degree of sharpness and microlobulation of mass margins. We calculated these features in a border region of the mass defined as a thin band along the mass contour. The importance of these features in the classification of benign and malignant masses was studied in relation to existing features used for mammographic mass detection. Features were divided into three groups, each representing a different mass segment: the interior region of a mass, the border and the outer area. The interior and the outer area of a mass were characterized using contrast and spiculation measures. Classification was done in two steps. First, features representing each of the three mass segments were merged into a neural network classifier resulting in a single regional classification score for each segment. Secondly, a classifier combined the three single scores into a final output to discriminate between benign and malignant lesions. We compared the classification performance of each regional classifier and the combined classifier on a data set of 1076 biopsy proved masses (590 malignant and 486 benign) from 481 women included in the Digital Database for Screening Mammography. Receiver operating characteristic (ROC) analysis was used to evaluate the accuracy of the classifiers. The area under the ROC curve (Az) was 0.69 for the interior mass segment, 0.76 for the border segment and 0.75 for the outer mass segment. The performance of the combined classifier was 0.81 for image-based and 0.83 for case-based evaluation. These results show that the combination of information from different mass segments is an effective approach for computer-aided characterization of mammographic masses. An advantage of this approach is that it allows the assessment of the contribution of regions rather than individual features. Results suggest that the border and the outer areas contained the most valuable information for discrimination between benign and malignant masses.

FUEL ELEMENT FOR NUCLEAR REACTORS

DOEpatents

Bassett, C.H.

1961-11-21

A fuel element is designed which is particularly adapted for reactors of high power density used to generate steam for the production of electricity. The fuel element consists of inner and outer concentric tubes forming an annular chamber within which is contained fissionable fuel pellet segments, wedge members interposed between the fuel segments, and a spring which, acting with wedge members, urges said fuel pellets radially into contact against the inner surface of the outer tube. The wedge members may be a fertile material convertible into fissionable fuel material by absorbing neutrons emitted from the fissionable fuel pellet segments. The costly grinding of cylindrical fuel pellets to close tolerances for snug engagement is reduced because the need to finish the exact size is eliminated. (AEC)

Sodium-dependent calcium extrusion and sensitivity regulation in retinal cones of the salamander.

PubMed Central

Nakatani, K; Yau, K W

1989-01-01

1. Membrane current was recorded from an isolated, dark-adapted salamander cone by sucking its inner segment into a tight-fitting glass pipette containing Ringer solution. The outer segment of the cell was exposed to a bath solution that could be changed rapidly. 2. After removing Na+ from the bath Ringer solution for a short period of time in darkness (the 'loading period'), a transient inward current was observed upon restoring it in bright light. A similar but longer-lasting current was observed when Na+ was restored in the light after a large Ca2+ influx was induced through the light-sensitive conductance in darkness. 3. The above transient current was not observed if Li+ or guanidinium was substituted for Na+ in the light, or if Ba2+ was substituted for Ca2+ during the dark loading period. However, a current was observed if Sr2+ was the substituting ion for Ca2+ during loading. These observations suggested that the current was associated with an electrogenic Na+-dependent Ca2+ efflux at the cone outer segment. 4. The saturated amplitude of the exchange current was 12-25 pA with a mean around 16 pA. This is very comparable to that measured in the outer segment of a salamander rod under similar conditions. 5. By comparing a known Ca2+ load in a cone outer segment to the subsequent charge transfer through the exchange, we estimated that the stoichiometry of the exchange was near 3Na+:1Ca2+. 6. With a small Ca2+ load, or in the presence of Cs+ around the inner segment, the final temporal decline of the Na+-Ca2+ exchange current was roughly exponential, with a mean time constant of about 100 ms. This decline is about four times faster than that measured in rods. We interpret the shorter time constant in cones to reflect a faster rate of decline of intracellular free Ca2+ in their outer segments resulting from the exchange activity. 7. In the absence of external Na+, and hence any Na+-dependent Ca2+ efflux, the absolute sensitivity of a cone to a dim flash was several times higher than in normal Ringer solution. 8. A roughly similar increase in light sensitivity was observed for a rod under the same conditions. 9. We conclude that the Na+-dependent Ca2+ efflux, through lowering intracellular free Ca2+ in the light, has a role in regulating the absolute light sensitivity in cones as it does in rods.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2479741

Photoreceptor Cells With Profound Structural Deficits Can Support Useful Vision in Mice

PubMed Central

Thompson, Stewart; Blodi, Frederick R.; Lee, Swan; Welder, Chris R.; Mullins, Robert F.; Tucker, Budd A.; Stasheff, Steven F.; Stone, Edwin M.

2014-01-01

Purpose. In animal models of degenerative photoreceptor disease, there has been some success in restoring photoreception by transplanting stem cell–derived photoreceptor cells into the subretinal space. However, only a small proportion of transplanted cells develop extended outer segments, considered critical for photoreceptor cell function. The purpose of this study was to determine whether photoreceptor cells that lack a fully formed outer segment could usefully contribute to vision. Methods. Retinal and visual function was tested in wild-type and Rds mice at 90 days of age (RdsP90). Photoreceptor cells of mice homozygous for the Rds mutation in peripherin 2 never develop a fully formed outer segment. The electroretinogram and multielectrode recording of retinal ganglion cells were used to test retinal responses to light. Three distinct visual behaviors were used to assess visual capabilities: the optokinetic tracking response, the discrimination-based visual water task, and a measure of the effect of vision on wheel running. Results. RdsP90 mice had reduced but measurable electroretinogram responses to light, and exhibited light-evoked responses in multiple types of retinal ganglion cells, the output neurons of the retina. In optokinetic and discrimination-based tests, acuity was measurable but reduced, most notably when contrast was decreased. The wheel running test showed that RdsP90 mice needed 3 log units brighter luminance than wild type to support useful vision (10 cd/m2). Conclusions. Photoreceptors that lack fully formed outer segments can support useful vision. This challenges the idea that normal cellular structure needs to be completely reproduced for transplanted cells to contribute to useful vision. PMID:24569582

Rescue of mutant rhodopsin traffic by metformin-induced AMPK activation accelerates photoreceptor degeneration

PubMed Central

Athanasiou, Dimitra; Aguila, Monica; Opefi, Chikwado A.; South, Kieron; Bellingham, James; Bevilacqua, Dalila; Munro, Peter M.; Kanuga, Naheed; Mackenzie, Francesca E.; Dubis, Adam M.; Georgiadis, Anastasios; Graca, Anna B.; Pearson, Rachael A.; Ali, Robin R.; Sakami, Sanae; Palczewski, Krzysztof; Sherman, Michael Y.; Reeves, Philip J.

2017-01-01

Abstract Protein misfolding caused by inherited mutations leads to loss of protein function and potentially toxic ‘gain of function’, such as the dominant P23H rhodopsin mutation that causes retinitis pigmentosa (RP). Here, we tested whether the AMPK activator metformin could affect the P23H rhodopsin synthesis and folding. In cell models, metformin treatment improved P23H rhodopsin folding and traffic. In animal models of P23H RP, metformin treatment successfully enhanced P23H traffic to the rod outer segment, but this led to reduced photoreceptor function and increased photoreceptor cell death. The metformin-rescued P23H rhodopsin was still intrinsically unstable and led to increased structural instability of the rod outer segments. These data suggest that improving the traffic of misfolding rhodopsin mutants is unlikely to be a practical therapy, because of their intrinsic instability and long half-life in the outer segment, but also highlights the potential of altering translation through AMPK to improve protein function in other protein misfolding diseases. PMID:28065882

Construction and Updating of Event Models in Auditory Event Processing

ERIC Educational Resources Information Center

Huff, Markus; Maurer, Annika E.; Brich, Irina; Pagenkopf, Anne; Wickelmaier, Florian; Papenmeier, Frank

2018-01-01

Humans segment the continuous stream of sensory information into distinct events at points of change. Between 2 events, humans perceive an event boundary. Present theories propose changes in the sensory information to trigger updating processes of the present event model. Increased encoding effort finally leads to a memory benefit at event…

Communication strategies in cosmetic surgery websites: an application of Taylor's six-segment message strategy wheel.

PubMed

Ahn, Ho-Young Anthony; Wu, Lei; Taylor, Ronald E

2013-01-01

Using Taylor's six-segment message strategy wheel as a theoretical framework, this study examines the communication approach (transmission or ritual) and message strategy (ego, social, sensory, routine, acute need, or ration) of cosmetic surgery websites. A content analysis revealed a fairly even division between transmission and ritual approaches. Ration strategy was the exclusive strategy in the websites adopting a transmission approach. No routine or acute need strategies were observed. Websites incorporating the ritual approach used ego, social, and sensory strategies. Human female models and natural objects were incorporated to deliver emotional persuasion. Implications for cosmetic surgery web marketers are discussed.

Restoration of outer segments of foveal photoreceptors after resolution of central serous chorioretinopathy.

PubMed

Ojima, Yumiko; Tsujikawa, Akitaka; Yamashiro, Kenji; Ooto, Sotaro; Tamura, Hiroshi; Yoshimura, Nagahisa

2010-01-01

To study morphologically and functionally the prognosis of damaged outer segments of the foveal photoreceptor layer in eyes with resolved central serous chorioretinopathy (CSC). We studied retrospectively the medical records of 70 patients (74 eyes) with resolved CSC. Optical coherence tomography was used to detect the junctions between inner and outer segments of the photoreceptors (IS/OS) as a hallmark of the integrity of the outer photoreceptor layer. In 53 eyes (71.6%), the IS/OS line was clearly detected beneath the fovea immediately after resolution of the retinal detachment, with good visual acuity (VA). In the remaining 21 eyes (28.4%), however, the foveal IS/OS line could not be detected shortly after resolution of CSC, and VA was variable, ranging from 0.1 to 1.5 (median, 0.9). Of these 21 eyes, 15 had a follow-up examination with OCT, and in four the foveal IS/OS line was not detected at the follow-up and vision in these eyes remained poor. However, nine eyes showed recovery of the foveal IS/OS line during follow-up, and these eyes had substantial visual recovery. Immediately after resolution of active CSC, although the IS/OS line cannot be detected beneath the fovea, it often shows restoration over time, with visual recovery, though in some eyes no restoration takes place and the prognosis remains poor.

High temperature control rod assembly

DOEpatents

Vollman, Russell E.

1991-01-01

A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

Prominin-1 Localizes to the Open Rims of Outer Segment Lamellae in Xenopus laevis Rod and Cone Photoreceptors

PubMed Central

Han, Zhou; Anderson, David W.

2012-01-01

Purpose. Prominin-1 expresses in rod and cone photoreceptors. Mutations in the prominin-1 gene cause retinal degeneration in humans. In this study, the authors investigated the expression and subcellular localization of xlProminin-1 protein, the Xenopus laevis ortholog of prominin-1, in rod and cone photoreceptors of this frog. Methods. Antibodies specific for xlProminin-1 were generated. Immunoblotting was used to study the expression and posttranslational processing of xlProminin-1 protein. Immunocytochemical light and electron microscopy and transgenesis were used to study the subcellular distribution of xlProminin-1. Results. xlProminin-1 is expressed and is subject to posttranslational proteolytic processing in the retina, brain, and kidney. xlProminin-1 is differently expressed and localized in outer segments of rod and cone photoreceptors of X. laevis. Antibodies specific for the N or C termini of xlProminin-1 labeled the open rims of lamellae of cone outer segments (COS) and the open lamellae at the base of rod outer segments (ROS). By contrast, anti–peripherin-2/rds antibody, Xper5A11, labeled the closed rims of cone lamellae adjacent to the ciliary axoneme and the rims of the closed ROS disks. The extent of labeling of the basal ROS by anti–xlProminin-1 antibodies varied with the light cycle in this frog. The entire ROS was also faintly labeled by both antibodies, a result that contrasts with the current notion that prominin-1 localizes only to the basal ROS. Conclusions. These findings suggest that xlProminin-1 may serve as an anti–fusogenic factor in the regulation of disk morphogenesis and may help to maintain the open lamellar structure of basal ROS and COS disks in X. laevis photoreceptors. PMID:22076989

Loss of ift122, a Retrograde Intraflagellar Transport (IFT) Complex Component, Leads to Slow, Progressive Photoreceptor Degeneration Due to Inefficient Opsin Transport.

PubMed

Boubakri, Meriam; Chaya, Taro; Hirata, Hiromi; Kajimura, Naoko; Kuwahara, Ryusuke; Ueno, Akiko; Malicki, Jarema; Furukawa, Takahisa; Omori, Yoshihiro

2016-11-18

In the retina, aberrant opsin transport from cell bodies to outer segments leads to retinal degenerative diseases such as retinitis pigmentosa. Opsin transport is facilitated by the intraflagellar transport (IFT) system that mediates the bidirectional movement of proteins within cilia. In contrast to functions of the anterograde transport executed by IFT complex B (IFT-B), the precise functions of the retrograde transport mediated by IFT complex A (IFT-A) have not been well studied in photoreceptor cilia. Here, we analyzed developing zebrafish larvae carrying a null mutation in ift122 encoding a component of IFT-A. ift122 mutant larvae show unexpectedly mild phenotypes, compared with those of mutants defective in IFT-B. ift122 mutants exhibit a slow onset of progressive photoreceptor degeneration mainly after 7 days post-fertilization. ift122 mutant larvae also develop cystic kidney but not curly body, both of which are typically observed in various ciliary mutants. ift122 mutants display a loss of cilia in the inner ear hair cells and nasal pit epithelia. Loss of ift122 causes disorganization of outer segment discs. Ectopic accumulation of an IFT-B component, ift88, is observed in the ift122 mutant photoreceptor cilia. In addition, pulse-chase experiments using GFP-opsin fusion proteins revealed that ift122 is required for the efficient transport of opsin and the distal elongation of outer segments. These results show that IFT-A is essential for the efficient transport of outer segment proteins, including opsin, and for the survival of retinal photoreceptor cells, rendering the ift122 mutant a unique model for human retinal degenerative diseases. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Loss of ift122, a Retrograde Intraflagellar Transport (IFT) Complex Component, Leads to Slow, Progressive Photoreceptor Degeneration Due to Inefficient Opsin Transport*

PubMed Central

Boubakri, Meriam; Chaya, Taro; Hirata, Hiromi; Kajimura, Naoko; Kuwahara, Ryusuke; Ueno, Akiko; Malicki, Jarema; Furukawa, Takahisa; Omori, Yoshihiro

2016-01-01

In the retina, aberrant opsin transport from cell bodies to outer segments leads to retinal degenerative diseases such as retinitis pigmentosa. Opsin transport is facilitated by the intraflagellar transport (IFT) system that mediates the bidirectional movement of proteins within cilia. In contrast to functions of the anterograde transport executed by IFT complex B (IFT-B), the precise functions of the retrograde transport mediated by IFT complex A (IFT-A) have not been well studied in photoreceptor cilia. Here, we analyzed developing zebrafish larvae carrying a null mutation in ift122 encoding a component of IFT-A. ift122 mutant larvae show unexpectedly mild phenotypes, compared with those of mutants defective in IFT-B. ift122 mutants exhibit a slow onset of progressive photoreceptor degeneration mainly after 7 days post-fertilization. ift122 mutant larvae also develop cystic kidney but not curly body, both of which are typically observed in various ciliary mutants. ift122 mutants display a loss of cilia in the inner ear hair cells and nasal pit epithelia. Loss of ift122 causes disorganization of outer segment discs. Ectopic accumulation of an IFT-B component, ift88, is observed in the ift122 mutant photoreceptor cilia. In addition, pulse-chase experiments using GFP-opsin fusion proteins revealed that ift122 is required for the efficient transport of opsin and the distal elongation of outer segments. These results show that IFT-A is essential for the efficient transport of outer segment proteins, including opsin, and for the survival of retinal photoreceptor cells, rendering the ift122 mutant a unique model for human retinal degenerative diseases. PMID:27681595

Why Do Children Pay More Attention to Grammatical Morphemes at the Ends of Sentences?

ERIC Educational Resources Information Center

Sundara, Megha

2018-01-01

Children pay more attention to the beginnings and ends of sentences rather than the middle. In natural speech, ends of sentences are prosodically and segmentally enhanced; they are also privileged by sensory and recall advantages. We contrasted whether acoustic enhancement or sensory and recall-related advantages are necessary and sufficient for…

Tastier and healthier alternatives to French fries.

PubMed

Rommens, Caius M; Shakya, Roshani; Heap, Mark; Fessenden, Kristi

2010-05-01

The effect of both the origin and shape of potato cuts on fry quality was investigated in this study. Linear strips from the inner core of tubers were compared to those from outer tissues, both before and after processing, and strips from either specific tissues or whole peeled tubers were also evaluated against ring-shaped cuts. Both strips and rings had 0.7 cm sides and, in most cases, a volume of 4.9 cm(3). They were analyzed for moisture content, antioxidants, asparagine, and reducing sugars. The material was then blanched, dipped in 0.5% disodium acid pyrophosphate and 0.3% glucose, dried at 77 degrees C, par-fried in soybean oil at 191 degrees C, and finish-fried at 168 degrees C. The fried product was analyzed for sensory characteristics and oil, salt, and acrylamide content. Our results showed that strips from the inner core absorbed 28% more oil and exhibited inferior sensory characteristics compared to strips from the outer parts. The extended drying and frying times needed to match the crispness and flavor of inner strips to those of regularly fried outer strips resulted in a further increased absorption of oil and, importantly, triggered a 163% increase in levels of the toxic Maillard reaction product acrylamide. Potato rings consisted of higher dry matter material, contained more antioxidants, and had a lower surface-to-volume ratio than the conventional linear strips. Upon processing, they also absorbed 22% less oil, contained 26% less salt, and displayed superior sensory properties. Thus, ring fries may represent an attractive alternative to French fries as processed staple food.

TIGRESS highly-segmented high-purity germanium clover detector

NASA Astrophysics Data System (ADS)

Scraggs, H. C.; Pearson, C. J.; Hackman, G.; Smith, M. B.; Austin, R. A. E.; Ball, G. C.; Boston, A. J.; Bricault, P.; Chakrawarthy, R. S.; Churchman, R.; Cowan, N.; Cronkhite, G.; Cunningham, E. S.; Drake, T. E.; Finlay, P.; Garrett, P. E.; Grinyer, G. F.; Hyland, B.; Jones, B.; Leslie, J. R.; Martin, J.-P.; Morris, D.; Morton, A. C.; Phillips, A. A.; Sarazin, F.; Schumaker, M. A.; Svensson, C. E.; Valiente-Dobón, J. J.; Waddington, J. C.; Watters, L. M.; Zimmerman, L.

2005-05-01

The TRIUMF-ISAC Gamma-Ray Escape-Suppressed Spectrometer (TIGRESS) will consist of twelve units of four high-purity germanium (HPGe) crystals in a common cryostat. The outer contacts of each crystal will be divided into four quadrants and two lateral segments for a total of eight outer contacts. The performance of a prototype HPGe four-crystal unit has been investigated. Integrated noise spectra for all contacts were measured. Energy resolutions, relative efficiencies for both individual crystals and for the entire unit, and peak-to-total ratios were measured with point-like sources. Position-dependent performance was measured by moving a collimated source across the face of the detector.

Interaction of 4.1G and cGMP-gated channels in rod photoreceptor outer segments.

PubMed

Cheng, Christiana L; Molday, Robert S

2013-12-15

In photoreceptors, the assembly of signaling molecules into macromolecular complexes is important for phototransduction and maintaining the structural integrity of rod outer segments (ROSs). However, the molecular composition and formation of these complexes are poorly understood. Using immunoprecipitation and mass spectrometry, 4.1G was identified as a new interacting partner for the cyclic-nucleotide gated (CNG) channels in ROSs. 4.1G is a widely expressed multifunctional protein that plays a role in the assembly and stability of membrane protein complexes. Multiple splice variants of 4.1G were cloned from bovine retina. A smaller splice variant of 4.1G selectively interacted with CNG channels not associated with peripherin-2-CNG channel complex. A combination of truncation studies and domain-binding assays demonstrated that CNG channels selectively interacted with 4.1G through their FERM and CTD domains. Using immunofluorescence, labeling of 4.1G was seen to be punctate and partially colocalized with CNG channels in the ROS. Our studies indicate that 4.1G interacts with a subset of CNG channels in the ROS and implicate this protein-protein interaction in organizing the spatial arrangement of CNG channels in the plasma membrane of outer segments.

Analysis of radially cracked ring segments subject to forces and couples

NASA Technical Reports Server (NTRS)

Gross, B.; Srawley, J. E.

1977-01-01

Results of planar boundary collocation analysis are given for ring segment (C-shaped) specimens with radial cracks, subjected to combined forces and couples. Mode I stress intensity factors and crack mouth opening displacements were determined for ratios of outer to inner radius in the range 1.1 to 2.5 and ratios of crack length to segment width in the range 0.1 to 0.8.

Analysis of radially cracked ring segments subject to forces and couples

NASA Technical Reports Server (NTRS)

Gross, B.; Strawley, J. E.

1975-01-01

Results of planar boundary collocation analysis are given for ring segment (C shaped) specimens with radial cracks, subjected to combined forces and couples. Mode I stress intensity factors and crack mouth opening displacements were determined for ratios of outer to inner radius in the range 1.1 to 2.5, and ratios of crack length to segment width in the range 0.1 to 0.8.

Automatic lumen and outer wall segmentation of the carotid artery using deformable three-dimensional models in MR angiography and vessel wall images.

PubMed

van 't Klooster, Ronald; de Koning, Patrick J H; Dehnavi, Reza Alizadeh; Tamsma, Jouke T; de Roos, Albert; Reiber, Johan H C; van der Geest, Rob J

2012-01-01

To develop and validate an automated segmentation technique for the detection of the lumen and outer wall boundaries in MR vessel wall studies of the common carotid artery. A new segmentation method was developed using a three-dimensional (3D) deformable vessel model requiring only one single user interaction by combining 3D MR angiography (MRA) and 2D vessel wall images. This vessel model is a 3D cylindrical Non-Uniform Rational B-Spline (NURBS) surface which can be deformed to fit the underlying image data. Image data of 45 subjects was used to validate the method by comparing manual and automatic segmentations. Vessel wall thickness and volume measurements obtained by both methods were compared. Substantial agreement was observed between manual and automatic segmentation; over 85% of the vessel wall contours were segmented successfully. The interclass correlation was 0.690 for the vessel wall thickness and 0.793 for the vessel wall volume. Compared with manual image analysis, the automated method demonstrated improved interobserver agreement and inter-scan reproducibility. Additionally, the proposed automated image analysis approach was substantially faster. This new automated method can reduce analysis time and enhance reproducibility of the quantification of vessel wall dimensions in clinical studies. Copyright © 2011 Wiley Periodicals, Inc.

Radio Frequency Trap for Containment of Plasmas in Antimatter Propulsion Systems Using Rotating Wall Electric Fields

NASA Technical Reports Server (NTRS)

Sims, William Herbert, III (Inventor); Martin, James Joseph (Inventor); Lewis, Raymond A. (Inventor)

2003-01-01

A containment apparatus for containing a cloud of charged particles comprises a cylindrical vacuum chamber having a longitudinal axis. Within the vacuum chamber is a containment region. A magnetic field is aligned with the longitudinal axis of the vacuum chamber. The magnetic field is time invariant and uniform in strength over the containment region. An electric field is also aligned with the longitudinal axis of the vacuum chamber and the magnetic field. The electric field is time invariant, and forms a potential well over the containment region. One or more means are disposed around the cloud of particles for inducing a rotating electric field internal to the vacuum chamber. The rotating electric field imparts energy to the charged particles within the containment region and compress the cloud of particles. The means disposed around the outer surface of the vacuum chamber for inducing a rotating electric field are four or more segments forming a segmented ring, the segments conforming to the outer surface of the vacuum chamber. Each of the segments is energized by a separate alternating voltage. The sum of the voltages imposed on each segment establishes the rotating field. When four segments form a ring, the rotating field is obtained by a signal generator applying a sinusoidal signal phase delayed by 90,180 and 270 degrees in sequence to the four segments.

Assessments of sensory plasticity after spinal cord injury across species.

PubMed

Haefeli, Jenny; Huie, J Russell; Morioka, Kazuhito; Ferguson, Adam R

2017-06-23

Spinal cord injury (SCI) is a multifaceted phenomenon associated with alterations in both motor function and sensory function. A majority of patients with SCI report sensory disturbances, including not only loss of sensation, but in many cases enhanced abnormal sensation, dysesthesia and pain. Development of therapeutics to treat these abnormal sensory changes require common measurement tools that can enable cross-species translation from animal models to human patients. We review the current literature on translational nociception/pain measurement in SCI and discuss areas for further development. Although a number of tools exist for measuring both segmental and affective sensory changes, we conclude that there is a pressing need for better, integrative measurement of nociception/pain outcomes across species to enhance precise therapeutic innovation for sensory dysfunction in SCI. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Increasing the efficiency of designing hemming processes by using an element-based metamodel approach

NASA Astrophysics Data System (ADS)

Kaiser, C.; Roll, K.; Volk, W.

2017-09-01

In the automotive industry, the manufacturing of automotive outer panels requires hemming processes in which two sheet metal parts are joined together by bending the flange of the outer part over the inner part. Because of decreasing development times and the steadily growing number of vehicle derivatives, an efficient digital product and process validation is necessary. Commonly used simulations, which are based on the finite element method, demand significant modelling effort, which results in disadvantages especially in the early product development phase. To increase the efficiency of designing hemming processes this paper presents a hemming-specific metamodel approach. The approach includes a part analysis in which the outline of the automotive outer panels is initially split into individual segments. By doing a para-metrization of each of the segments and assigning basic geometric shapes, the outline of the part is approximated. Based on this, the hemming parameters such as flange length, roll-in, wrinkling and plastic strains are calculated for each of the geometric basic shapes by performing a meta-model-based segmental product validation. The metamodel is based on an element similar formulation that includes a reference dataset of various geometric basic shapes. A random automotive outer panel can now be analysed and optimized based on the hemming-specific database. By implementing this approach into a planning system, an efficient optimization of designing hemming processes will be enabled. Furthermore, valuable time and cost benefits can be realized in a vehicle’s development process.

Early photoreceptor outer segment loss and retinoschisis in Cohen syndrome.

PubMed

Uyhazi, Katherine E; Binenbaum, Gil; Carducci, Nicholas; Zackai, Elaine H; Aleman, Tomas S

2018-06-01

To describe early structural and functional retinal changes in a patient with Cohen syndrome. A 13-month-old Caucasian girl of Irish and Spanish ancestry was noted to have micrognathia and laryngomalacia at birth, which prompted a genetic evaluation that revealed biallelic deletions in COH1 (VPS13B) (a maternally inherited 60-kb deletion involving exons 26-32 and a paternally inherited 3.5-kb deletion within exon 17) consistent with Cohen syndrome. She underwent a complete ophthalmic examination, full-field flash electroretinography and retinal imaging with spectral domain optical coherence tomography. Central vision was central, steady, and maintained. There was bilateral myopic astigmatic refractive error. Fundus exam was notable for dark foveolar pigmentation, but no obvious abnormalities of either eye. Spectral domain optical coherence tomography cross sections through the fovea revealed a normal appearing photoreceptor outer nuclear layer but loss of the interdigitation signal between the photoreceptor outer segments and the apical retinal pigment epithelium. Retinoschisis involving the inner nuclear layer of both eyes and possible ganglion cell layer thinning were also noted. There was a detectable electroretinogram with similarly reduced amplitudes of rod- (white, 0.01 cd.s.m -2 ) and cone-mediated (3 cd.s.m -2 , 30 Hz) responses. Photoreceptor outer segment abnormalities and retinoschisis may represent the earliest structural retinal change detected by spectral domain optical coherence tomography in patients with Cohen syndrome, suggesting a complex pathophysiology with primary involvement of the photoreceptor cilium and disorganization of the structural integrity of the inner retina.

Advanced two-layer level set with a soft distance constraint for dual surfaces segmentation in medical images

NASA Astrophysics Data System (ADS)

Ji, Yuanbo; van der Geest, Rob J.; Nazarian, Saman; Lelieveldt, Boudewijn P. F.; Tao, Qian

2018-03-01

Anatomical objects in medical images very often have dual contours or surfaces that are highly correlated. Manually segmenting both of them by following local image details is tedious and subjective. In this study, we proposed a two-layer region-based level set method with a soft distance constraint, which not only regularizes the level set evolution at two levels, but also imposes prior information on wall thickness in an effective manner. By updating the level set function and distance constraint functions alternatingly, the method simultaneously optimizes both contours while regularizing their distance. The method was applied to segment the inner and outer wall of both left atrium (LA) and left ventricle (LV) from MR images, using a rough initialization from inside the blood pool. Compared to manual annotation from experience observers, the proposed method achieved an average perpendicular distance (APD) of less than 1mm for the LA segmentation, and less than 1.5mm for the LV segmentation, at both inner and outer contours. The method can be used as a practical tool for fast and accurate dual wall annotations given proper initialization.

Three-axis asymmetric radiation detector system

DOEpatents

Martini, Mario Pierangelo; Gedcke, Dale A.; Raudorf, Thomas W.; Sangsingkeow, Pat

2000-01-01

A three-axis radiation detection system whose inner and outer electrodes are shaped and positioned so that the shortest path between any point on the inner electrode and the outer electrode is a different length whereby the rise time of a pulse derived from a detected radiation event can uniquely define the azimuthal and radial position of that event, and the outer electrode is divided into a plurality of segments in the longitudinal axial direction for locating the axial location of a radiation detection event occurring in the diode.

Spatiotemporal definition of neurite outgrowth, refinement and retraction in the developing mouse cochlea.

PubMed

Huang, Lin-Chien; Thorne, Peter R; Housley, Gary D; Montgomery, Johanna M

2007-08-01

The adult mammalian cochlea receives dual afferent innervation: the inner sensory hair cells are innervated exclusively by type I spiral ganglion neurons (SGN), whereas the sensory outer hair cells are innervated by type II SGN. We have characterized the spatiotemporal reorganization of the dual afferent innervation pattern as it is established in the developing mouse cochlea. This reorganization occurs during the first postnatal week just before the onset of hearing. Our data reveal three distinct phases in the development of the afferent innervation of the organ of Corti: (1) neurite growth and extension of both classes of afferents to all hair cells (E18-P0); (2) neurite refinement, with formation of the outer spiral bundles innervating outer hair cells (P0-P3); (3) neurite retraction and synaptic pruning to eliminate type I SGN innervation of outer hair cells, while retaining their innervation of inner hair cells (P3-P6). The characterization of this developmental innervation pattern was made possible by the finding that tetramethylrhodamine-conjugated dextran (TMRD) specifically labeled type I SGN. Peripherin and choline-acetyltransferase immunofluorescence confirmed the type II and efferent innervation patterns, respectively, and verified the specificity of the type I SGN neurites labeled by TMRD. These findings define the precise spatiotemporal neurite reorganization of the two afferent nerve fiber populations in the cochlea, which is crucial for auditory neurotransmission. This reorganization also establishes the cochlea as a model system for studying CNS synapse development, plasticity and elimination.

ACUTE ZONAL OCCULT OUTER RETINOPATHY: Structural and Functional Analysis Across the Transition Zone Between Healthy and Diseased Retina.

PubMed

Duncker, Tobias; Lee, Winston; Jiang, Fan; Ramachandran, Rithambara; Hood, Donald C; Tsang, Stephen H; Sparrow, Janet R; Greenstein, Vivienne C

2018-01-01

To assess structure and function across the transition zone (TZ) between relatively healthy and diseased retina in acute zonal occult outer retinopathy. Six patients (6 eyes; age 22-71 years) with acute zonal occult outer retinopathy were studied. Spectral-domain optical coherence tomography, fundus autofluorescence, near-infrared reflectance, color fundus photography, and fundus perimetry were performed and images were registered to each other. The retinal layers of the spectral-domain optical coherence tomography scans were segmented and the thicknesses of two outer retinal layers, that is, the total receptor and outer segment plus layers, and the retinal nerve fiber layer were measured. All eyes showed a TZ on multimodal imaging. On spectral-domain optical coherence tomography, the TZ was in the nasal retina at varying distances from the fovea. For all eyes, it was associated with loss of the ellipsoid zone band, significant thinning of the two outer retinal layers, and in three eyes with thickening of the retinal nerve fiber layer. On fundus autofluorescence, all eyes had a clearly demarcated peripapillary area of abnormal fundus autofluorescence delimited by a border of high autofluorescence; the latter was associated with loss of the ellipsoid zone band and with a change from relatively normal to markedly decreased or nonrecordable visual sensitivity on fundus perimetry. The results of multimodal imaging clarified the TZ in acute zonal occult outer retinopathy. The TZ was outlined by a distinct high autofluorescence border that correlated with loss of the ellipsoid zone band on spectral-domain optical coherence tomography. However, in fundus areas that seemed healthy on fundus autofluorescence, thinning of the outer retinal layers and thickening of the retinal nerve fiber layer were observed near the TZ. The TZ was also characterized by a decrease in visual sensitivity.

Increasing the feasibility of minimally invasive procedures in type A aortic dissections: a framework for segmentation and quantification.

PubMed

Morariu, Cosmin Adrian; Terheiden, Tobias; Dohle, Daniel Sebastian; Tsagakis, Konstantinos; Pauli, Josef

2016-02-01

Our goal is to provide precise measurements of the aortic dimensions in case of dissection pathologies. Quantification of surface lengths and aortic radii/diameters together with the visualization of the dissection membrane represents crucial prerequisites for enabling minimally invasive treatment of type A dissections, which always also imply the ascending aorta. We seek a measure invariant to luminance and contrast for aortic outer wall segmentation. Therefore, we propose a 2D graph-based approach using phase congruency combined with additional features. Phase congruency is extended to 3D by designing a novel conic directional filter and adding a lowpass component to the 3D Log-Gabor filterbank for extracting the fine dissection membrane, which separates the true lumen from the false one within the aorta. The result of the outer wall segmentation is compared with manually annotated axial slices belonging to 11 CTA datasets. Quantitative assessment of our novel 2D/3D membrane extraction algorithms has been obtained for 10 datasets and reveals subvoxel accuracy in all cases. Aortic inner and outer surface lengths, determined within 2 cadaveric CT datasets, are validated against manual measurements performed by a vascular surgeon on excised aortas of the body donors. This contribution proposes a complete pipeline for segmentation and quantification of aortic dissections. Validation against ground truth of the 3D contour lengths quantification represents a significant step toward custom-designed stent-grafts.

Light-dependent translocation of arrestin in rod photoreceptors is signaled through a phospholipase C cascade and requires ATP.

PubMed

Orisme, Wilda; Li, Jian; Goldmann, Tobias; Bolch, Susan; Wolfrum, Uwe; Smith, W Clay

2010-03-01

Partitioning of cellular components is a critical mechanism by which cells can regulate their activity. In rod photoreceptors, light induces a large-scale translocation of arrestin from the inner segments to the outer segments. The purpose of this project is to elucidate the signaling pathway necessary to initiate arrestin translocation to the outer segments and the mechanism for arrestin translocation. Mouse retinal organotypic cultures and eyes from transgenic Xenopus tadpoles expressing a fusion of GFP and rod arrestin were treated with both activators and inhibitors of proteins in the phosphoinositide pathway. Confocal microscopy was used to image the effects of the pharmacological agents on arrestin translocation in rod photoreceptors. Retinas were also depleted of ATP using potassium cyanide to assess the requirement for ATP in arrestin translocation. In this study, we demonstrate that components of the G-protein-linked phospholipase C (PLC) pathway play a role in initiating arrestin translocation. Our results show that arrestin translocation can be stimulated by activators of PLC and protein kinase C (PKC), and by cholera toxin in the absence of light. Arrestin translocation to the outer segments is significantly reduced by inhibitors of PLC and PKC. Importantly, we find that treatment with potassium cyanide inhibits arrestin translocation in response to light. Collectively, our results suggest that arrestin translocation is initiated by a G-protein-coupled cascade through PLC and PKC signaling. Furthermore, our results demonstrate that at least the initiation of arrestin translocation requires energy input.

Evolution of Magnetic Rayleigh–Taylor Instability into the Outer Solar Corona and Low Interplanetary Space

NASA Astrophysics Data System (ADS)

Mishra, Sudheer K.; Singh, Talwinder; Kayshap, P.; Srivastava, A. K.

2018-03-01

We analyze the observations from Solar TErrestrial RElations Observatory (STEREO)-A and B/COR-1 of an eruptive prominence in the intermediate corona on 2011 June 7 at 08:45 UT, which consists of magnetic Rayleigh–Taylor (MRT) unstable plasma segments. Its upper-northward segment shows spatio-temporal evolution of MRT instability in form of finger structures up to the outer corona and low interplanetary space. Using the method of Dolei et al., It is estimated that the density in each bright finger is greater than the corresponding dark region lying below it in the surrounding intermediate corona. The instability is evolved due to wave perturbations that are parallel to the magnetic field at the density interface. We conjecture that the prominence plasma is supported by tension component of the magnetic field against gravity. Through the use of linear stability theory, the magnetic field is estimated as 21–40 mG to suppress growth of MRT instability in the observed finger structures. In the southward plasma segment, a horn-like structure is observed at 11:55 UT in the intermediate corona that also indicates MRT instability. Falling blobs are also observed in both of the plasma segments. In the outer corona, up to 6–13 solar radii, the mushroom-like plasma structures have been identified in the upper-northward MRT unstable plasma segment using STEREO-A/COR-2. These structures most likely grew due to the breaking and twisting of fingers at large spatial scales in weaker magnetic fields. In the lower interplanetary space up to 20 solar radii, these structures are fragmented into various small-scale localized plasma spikes, most likely due to turbulent mixing.

Acetylcholine and lobster sensory neurones

PubMed Central

Barker, David L.; Herbert, Edward; Hildebrand, John G.; Kravitz, Edward A.

1972-01-01

Experiments are presented in support of the hypothesis that acetylcholine functions as a sensory transmitter in the lobster nervous system. 1. Several different peripheral sensory structures incorporate radioactive choline into acetylcholine. The preparation most enriched in sensory as opposed to other nervous elements (the antennular sense organs of the distal outer flagellum) does not incorporate significant amounts of glutamate, tyrosine or tryptophan into any of the other major transmitter candidates. 2. There is a parallel between the distribution of the enzyme choline acetyltransferase and the proportion of sensory fibres in nervous tissue from many parts of the lobster nervous system. 3. Isolated sensory axons contain at least 500 times as much choline acetyltransferase per cm of axon as do efferent excitatory and inhibitory fibres. 4. Abdominal ganglia and root stumps show a decline in the rate of incorporation of choline into acetylcholine 2 to 8 weeks after severing the first and second roots bilaterally (leaving the connectives and third roots intact). Extracts of the root stumps exhibit a significantly lower level of choline acetyltransferase 2 weeks after this operation. 5. Curare and atropine partially block an identified sensory synapse in the lobster abdominal ganglion. ImagesText-fig. 4Text-fig. 5Plate 1 PMID:4343316

Light-Induced Translocation of RGS9-1 and Gβ5L in Mouse Rod Photoreceptors

PubMed Central

Tian, Mei; Zallocchi, Marisa; Wang, Weimin; Chen, Ching-Kang; Palczewski, Krzysztof; Delimont, Duane; Cosgrove, Dominic; Peng, You-Wei

2013-01-01

The transducin GTPase-accelerating protein complex, which determines the photoresponse duration of photoreceptors, is composed of RGS9-1, Gβ5L and R9AP. Here we report that RGS9-1 and Gβ5L change their distribution in rods during light/dark adaptation. Upon prolonged dark adaptation, RGS9-1 and Gβ5L are primarily located in rod inner segments. But very dim-light exposure quickly translocates them to the outer segments. In contrast, their anchor protein R9AP remains in the outer segment at all times. In the dark, Gβ5L's interaction with R9AP decreases significantly and RGS9-1 is phosphorylated at S475 to a significant degree. Dim light exposure leads to quick de-phosphorylation of RGS9-1. Furthermore, after prolonged dark adaptation, RGS9-1 and transducin Gα are located in different cellular compartments. These results suggest a previously unappreciated mechanism by which prolonged dark adaptation leads to increased light sensitivity in rods by dissociating RGS9-1 from R9AP and redistributing it to rod inner segments. PMID:23555598

Live-Cell Imaging of Phagosome Motility in Primary Mouse RPE Cells.

PubMed

Hazim, Roni; Jiang, Mei; Esteve-Rudd, Julian; Diemer, Tanja; Lopes, Vanda S; Williams, David S

2016-01-01

The retinal pigment epithelium (RPE) is a post-mitotic epithelial monolayer situated between the light-sensitive photoreceptors and the choriocapillaris. Given its vital functions for healthy vision, the RPE is a primary target for insults that result in blinding diseases, including age-related macular degeneration (AMD). One such function is the phagocytosis and digestion of shed photoreceptor outer segments. In the present study, we examined the process of trafficking of outer segment disk membranes in live cultures of primary mouse RPE, using high speed spinning disk confocal microscopy. This approach has enabled us to track phagosomes, and determine parameters of their motility, which are important for their efficient degradation.

Foveal cone spacing and cone photopigment density difference: objective measurements in the same subjects.

PubMed

Marcos, S; Tornow, R P; Elsner, A E; Navarro, R

1997-07-01

Foveal cone spacing was measured in vivo using an objective technique: ocular speckle interferometry. Cone packing density was computed from cone spacing data. Foveal cone photopigment density difference was measured in the same subjects using retinal densitometry with a scanning laser ophthalmoscope. Both the cone packing density and cone photopigment density difference decreased sharply with increasing retinal eccentricity. From the comparison of both sets of measurements, the computed amounts of photopigment per cone increased slightly with increasing retinal eccentricity. Consistent with previous results, decreases in cone outer segment length are over-compensated by an increase in the outer segment area, at least in retinal eccentricities up to 1 deg.

Shoreline configuration and shoreline dynamics: A mesoscale analysis. [Assateague Island and Outer Banks of North Carolina

NASA Technical Reports Server (NTRS)

Dolan, R. (Principal Investigator); Hayden, B. P.; Heywood, J. E.

1975-01-01

The author has identified the following significant results. Atlantic coast barrier island shorelines are seldom straight, but rather sinuous. These shoreline curvatures range in size from cusps to capes. Significant relationships exist between the orientation of shoreline segments within the larger of these sinuous features and shoreline dynamics, with coefficients ranging up to .9. Orientation of the shoreline segments of Assateague Island (60 km) and the Outer Banks of North Carolina (130 km) was measured from LANDSAT 2 imagery (1:80,000) and high altitude aerial photography (1:120,000). Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes.

Progression of changes in the sensorial elements of the cochlear and peripheral vestibular systems: The otitis media continuum.

PubMed

Monsanto, Rafael da Costa; Schachern, Patricia; Paparella, Michael M; Cureoglu, Sebahattin; Penido, Norma de Oliveira

2017-08-01

Our study aimed to evaluate pathologic changes in the cochlear (inner and outer hair cells and stria vascularis) and vestibular (vestibular hair cells, dark, and transitional cells) sensorial elements in temporal bones from donors who had otitis media. We studied 40 temporal bones from such donors, which were categorized in serous otitis media (SOM), serous-purulent otitis media (SPOM), mucoid/mucoid-purulent otitis media (MOM/MPOM), and chronic otitis media (COM); control group comprised 10 nondiseased temporal bones. We found significant loss of inner and outer cochlear hair cells in the basal turn of the SPOM, MOM/MPOM and COM groups; significant loss of vestibular hair cells was observed in the MOM/MPOM and COM groups. All otitis media groups had smaller mean area of the stria vascularis in the basal turn of the cochlea when compared to controls. In conclusion, our study demonstrated more severe pathologic changes in the later stages of the continuum of otitis media (MOM/MPOM and COM). Those changes seem to progress from the basal turn of the cochlea (stria vascularis, then inner and outer hair cells) to the middle turn of the cochlea and to the saccule and utricle in the MOM/MPOM and COM stages. Copyright © 2017 Elsevier B.V. All rights reserved.

Multifocal sensory demyelinating neuropathy: Report of a case.

PubMed

Oh, Shin J

2017-10-01

Multifocal sensory demyelinating neuropathy has not been adequately reported in the literature. A 42-year-old man with numbness of the left hand for 3 years and of the right hand for 6 months had a pure multifocal sensory neuropathy involving both hands, most prominently affecting 2-point discrimination, number writing, and object recognition of the left hand. Near-nerve needle sensory and mixed nerve conduction studies were performed on the left ulnar nerve. Studies of the left ulnar nerve documented a demyelinating neuropathy characterized by temporal dispersion and marked decrease in the amplitudes of the sensory and mixed compound nerve potentials in the above-elbow-axilla segment. With intravenous immunoglobulin treatment, there was improvement in his neuropathic condition. In this study I describe a case of multifocal sensory demyelinating neuropathy as a counterpart of multifocal motor neuropathy. Muscle Nerve 56: 825-828, 2017. © 2016 Wiley Periodicals, Inc.

Identification of sensory attributes that drive consumer liking of commercial orange juice products in Korea.

PubMed

Kim, Mina K; Lee, Young-Jin; Kwak, Han Sub; Kang, Myung-woo

2013-09-01

Orange juice is a well-accepted fruit juice, and its consumption increases steadily. Many studies have been conducted to understand the sensory characteristics of orange juice throughout its varying processing steps. Sensory language and consumer likings of food can be influenced by culture. The objective of this study is to evaluate the sensory characteristics of commercially available orange juices in Korea and identify drivers of liking for orange juices in Korea. A quantitative descriptive analysis was conducted using a trained panel (n = 10) to evaluate 7 orange juice samples in triplicates, followed by consumer acceptance tests (n = 103). Univariate and multivariate statistical analyses were conducted for data analysis. The sensory characteristics of commercially available orange juice were documented and grouped: group 1 samples were characterized by high in natural citrus flavors such as orange peel, orange flesh, citrus fruit, and grape fruit, whereas group 2 samples were characterized by processed orange-like flavors such as over-ripe, cooked-orange, and yogurt. Regardless of orange flavor types, a high intensity of orange flavor in orange juice was identified as a driver of liking for orange juices in Korea. Three distinct clusters were segmented by varying sensory attributes that were evaluated by likes and dislikes. Overall, many similarities were noticed between Korean market segment and global orange juice market. By knowing the drivers of liking and understanding the distinct consumer clusters present in the Korean orange juice market, the orange juice industry could improve the strategic marketing of its products in Korea. © 2013 Institute of Food Technologists®

Ear Deformations Give Bats a Physical Mechanism for Fast Adaptation of Ultrasonic Beam Patterns

NASA Astrophysics Data System (ADS)

Gao, Li; Balakrishnan, Sreenath; He, Weikai; Yan, Zhen; Müller, Rolf

2011-11-01

A large number of mammals, including humans, have intricate outer ear shapes that diffract incoming sound in a direction- and frequency-specific manner. Through this physical process, the outer ear shapes encode sound-source information into the sensory signals from each ear. Our results show that horseshoe bats could dynamically control these diffraction processes through fast nonrigid ear deformations. The bats’ ear shapes can alter between extreme configurations in about 100 ms and thereby change their acoustic properties in ways that would suit different acoustic sensing tasks.

Live Imaging of LysoTracker-Labelled Phagolysosomes Tracks Diurnal Phagocytosis of Photoreceptor Outer Segment Fragments in Rat RPE Tissue Ex Vivo.

PubMed

Mao, Yingyu; Finnemann, Silvia C

2016-01-01

Renewal of rod photoreceptor outer segments in the mammalian eye involves synchronized diurnal shedding after light onset of spent distal outer segment fragments (POS) linked to swift clearance of shed POS from the subretinal space by the adjacent retinal pigment epithelium (RPE). Engulfed POS phagosomes in RPE cells mature to acidified phagolysosomes, which accomplish enzymatic degradation of POS macromolecules. Here, we used an acidophilic fluorophore LysoTracker to label acidic organelles in freshly dissected, live rat RPE tissue flat mounts. We observed that all RPE cells imaged contained numerous acidified POS phagolysosomes whose abundance per cell was dramatically increased 2 h after light onset as compared to either 1 h before or 4 h after light onset. Lack of organelles of similar diameter (of 1-2 μm) in phagocytosis-defective mutant RCS rat RPE confirmed that LysoTracker live imaging detected POS phagolysosomes. Lack of increase in lysosomal membrane protein LAMP-1 in RPE/choroid during the diurnal phagocytic burst suggests that formation of POS phagolysosomes in RPE in situ may not involve extra lysosome membrane biogenesis. Taken together, we report a new imaging approach that directly detects POS phagosome acidification and allows rapid tracking and quantification of POS phagocytosis by live RPE -tissue ex situ.

Recirculating electric air filter

DOEpatents

Bergman, Werner

1986-01-01

An electric air filter cartridge has a cylindrical inner high voltage eleode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

Recirculating electric air filter

DOEpatents

Bergman, W.

1985-01-09

An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

The Cellular Origins of the Outer Retinal Bands in Optical Coherence Tomography Images

PubMed Central

Jonnal, Ravi S.; Kocaoglu, Omer P.; Zawadzki, Robert J.; Lee, Sang-Hyuck; Werner, John S.; Miller, Donald T.

2014-01-01

Purpose. To test the recently proposed hypothesis that the second outer retinal band, observed in clinical OCT images, originates from the inner segment ellipsoid, by measuring: (1) the thickness of this band within single cone photoreceptors, and (2) its respective distance from the putative external limiting membrane (band 1) and cone outer segment tips (band 3). Methods. Adaptive optics-optical coherence tomography images were acquired from four subjects without known retinal disease. Images were obtained at foveal (2°) and perifoveal (5°) locations. Cone photoreceptors (n = 9593) were identified and segmented in three dimensions using custom software. Features corresponding to bands 1, 2, and 3 were automatically identified. The thickness of band 2 was assessed in each cell by fitting the longitudinal reflectance profile of the band with a Gaussian function. Distances between bands 1 and 2, and between 2 and 3, respectively, were also measured in each cell. Two independent calibration techniques were employed to determine the depth scale (physical length per pixel) of the imaging system. Results. When resolved within single cells, the thickness of band 2 is a factor of three to four times narrower than in corresponding clinical OCT images. The distribution of band 2 thickness across subjects and eccentricities had a modal value of 4.7 μm, with 48% of the cones falling between 4.1 and 5.2 μm. No significant differences were found between cells in the fovea and perifovea. The distance separating bands 1 and 2 was found to be larger than the distance between bands 2 and 3, across subjects and eccentricities, with a significantly larger difference at 5° than 2°. Conclusions. On the basis of these findings, we suggest that ascription of the outer retinal band 2 to the inner segment ellipsoid is unjustified, because the ellipsoid is both too thick and proximally located to produce the band. PMID:25324288

Automated segmentation of mouse OCT volumes (ASiMOV): Validation & clinical study of a light damage model.

PubMed

Antony, Bhavna Josephine; Kim, Byung-Jin; Lang, Andrew; Carass, Aaron; Prince, Jerry L; Zack, Donald J

2017-01-01

The use of spectral-domain optical coherence tomography (SD-OCT) is becoming commonplace for the in vivo longitudinal study of murine models of ophthalmic disease. Longitudinal studies, however, generate large quantities of data, the manual analysis of which is very challenging due to the time-consuming nature of generating delineations. Thus, it is of importance that automated algorithms be developed to facilitate accurate and timely analysis of these large datasets. Furthermore, as the models target a variety of diseases, the associated structural changes can also be extremely disparate. For instance, in the light damage (LD) model, which is frequently used to study photoreceptor degeneration, the outer retina appears dramatically different from the normal retina. To address these concerns, we have developed a flexible graph-based algorithm for the automated segmentation of mouse OCT volumes (ASiMOV). This approach incorporates a machine-learning component that can be easily trained for different disease models. To validate ASiMOV, the automated results were compared to manual delineations obtained from three raters on healthy and BALB/cJ mice post LD. It was also used to study a longitudinal LD model, where five control and five LD mice were imaged at four timepoints post LD. The total retinal thickness and the outer retina (comprising the outer nuclear layer, and inner and outer segments of the photoreceptors) were unchanged the day after the LD, but subsequently thinned significantly (p < 0.01). The retinal nerve fiber-ganglion cell complex and the inner plexiform layers, however, remained unchanged for the duration of the study.

Automated segmentation of mouse OCT volumes (ASiMOV): Validation & clinical study of a light damage model

PubMed Central

Lang, Andrew; Carass, Aaron; Prince, Jerry L.; Zack, Donald J.

2017-01-01

The use of spectral-domain optical coherence tomography (SD-OCT) is becoming commonplace for the in vivo longitudinal study of murine models of ophthalmic disease. Longitudinal studies, however, generate large quantities of data, the manual analysis of which is very challenging due to the time-consuming nature of generating delineations. Thus, it is of importance that automated algorithms be developed to facilitate accurate and timely analysis of these large datasets. Furthermore, as the models target a variety of diseases, the associated structural changes can also be extremely disparate. For instance, in the light damage (LD) model, which is frequently used to study photoreceptor degeneration, the outer retina appears dramatically different from the normal retina. To address these concerns, we have developed a flexible graph-based algorithm for the automated segmentation of mouse OCT volumes (ASiMOV). This approach incorporates a machine-learning component that can be easily trained for different disease models. To validate ASiMOV, the automated results were compared to manual delineations obtained from three raters on healthy and BALB/cJ mice post LD. It was also used to study a longitudinal LD model, where five control and five LD mice were imaged at four timepoints post LD. The total retinal thickness and the outer retina (comprising the outer nuclear layer, and inner and outer segments of the photoreceptors) were unchanged the day after the LD, but subsequently thinned significantly (p < 0.01). The retinal nerve fiber-ganglion cell complex and the inner plexiform layers, however, remained unchanged for the duration of the study. PMID:28817571

Automatic plaque characterization and vessel wall segmentation in magnetic resonance images of atherosclerotic carotid arteries

NASA Astrophysics Data System (ADS)

Adame, Isabel M.; van der Geest, Rob J.; Wasserman, Bruce A.; Mohamed, Mona; Reiber, Johan H. C.; Lelieveldt, Boudewijn P. F.

2004-05-01

Composition and structure of atherosclerotic plaque is a primary focus of cardiovascular research. In vivo MRI provides a meanse to non-invasively image and assess the morphological features of athersclerotic and normal human carotid arteries. To quantitatively assess the vulnerability and the type of plaque, the contours of the lumen, outer boundary of the vessel wall and plaque components, need to be traced. To achieve this goal, we have developed an automated contou detection technique, which consists of three consecutive steps: firstly, the outer boundary of the vessel wall is detected by means of an ellipse-fitting procedure in order to obtain smoothed shapes; secondly, the lumen is segnented using fuzzy clustering. Thre region to be classified is that within the outer vessel wall boundary obtained from the previous step; finally, for plaque detection we follow the same approach as for lumen segmentation: fuzzy clustering. However, plaque is more difficult to segment, as the pixel gray value can differ considerably from one region to another, even when it corresponds to the same type of tissue. That makes further processing necessary. All these three steps might be carried out combining information from different sequences (PD-, T2-, T1-weighted images, pre- and post-contrast), to improve the contour detection. The algorithm has been validated in vivo on 58 high-resolution PD and T1 weighted MR images (19 patients). The results demonstrate excellent correspondence between automatic and manual area measurements: lumen (r=0.94), outer (r=0.92), and acceptable for fibrous cap thickness (r=0.76).

In Vivo Imaging of Human Cone Photoreceptor Inner Segments

PubMed Central

Scoles, Drew; Sulai, Yusufu N.; Langlo, Christopher S.; Fishman, Gerald A.; Curcio, Christine A.; Carroll, Joseph; Dubra, Alfredo

2014-01-01

Purpose. An often overlooked prerequisite to cone photoreceptor gene therapy development is residual photoreceptor structure that can be rescued. While advances in adaptive optics (AO) retinal imaging have recently enabled direct visualization of individual cone and rod photoreceptors in the living human retina, these techniques largely detect strongly directionally-backscattered (waveguided) light from normal intact photoreceptors. This represents a major limitation in using existing AO imaging to quantify structure of remnant cones in degenerating retina. Methods. Photoreceptor inner segment structure was assessed with a novel AO scanning light ophthalmoscopy (AOSLO) differential phase technique, that we termed nonconfocal split-detector, in two healthy subjects and four subjects with achromatopsia. Ex vivo preparations of five healthy donor eyes were analyzed for comparison of inner segment diameter to that measured in vivo with split-detector AOSLO. Results. Nonconfocal split-detector AOSLO reveals the photoreceptor inner segment with or without the presence of a waveguiding outer segment. The diameter of inner segments measured in vivo is in good agreement with histology. A substantial number of foveal and parafoveal cone photoreceptors with apparently intact inner segments were identified in patients with the inherited disease achromatopsia. Conclusions. The application of nonconfocal split-detector to emerging human gene therapy trials will improve the potential of therapeutic success, by identifying patients with sufficient retained photoreceptor structure to benefit the most from intervention. Additionally, split-detector imaging may be useful for studies of other retinal degenerations such as AMD, retinitis pigmentosa, and choroideremia where the outer segment is lost before the remainder of the photoreceptor cell. PMID:24906859

Recurrent network dynamics reconciles visual motion segmentation and integration.

PubMed

Medathati, N V Kartheek; Rankin, James; Meso, Andrew I; Kornprobst, Pierre; Masson, Guillaume S

2017-09-12

In sensory systems, a range of computational rules are presumed to be implemented by neuronal subpopulations with different tuning functions. For instance, in primate cortical area MT, different classes of direction-selective cells have been identified and related either to motion integration, segmentation or transparency. Still, how such different tuning properties are constructed is unclear. The dominant theoretical viewpoint based on a linear-nonlinear feed-forward cascade does not account for their complex temporal dynamics and their versatility when facing different input statistics. Here, we demonstrate that a recurrent network model of visual motion processing can reconcile these different properties. Using a ring network, we show how excitatory and inhibitory interactions can implement different computational rules such as vector averaging, winner-take-all or superposition. The model also captures ordered temporal transitions between these behaviors. In particular, depending on the inhibition regime the network can switch from motion integration to segmentation, thus being able to compute either a single pattern motion or to superpose multiple inputs as in motion transparency. We thus demonstrate that recurrent architectures can adaptively give rise to different cortical computational regimes depending upon the input statistics, from sensory flow integration to segmentation.

The effect of light on outer segment calcium in salamander rods

PubMed Central

Matthews, Hugh R; Fain, Gordon L

2003-01-01

Calcium acts as a second messenger in vertebrate rods, regulating the recovery phase of the light response and modulating sensitivity during light-adaptation. Since light not only decreases the outer segment calcium concentration ([Ca2+]i) by closing cyclic nucleotide-gated channels but can also increase [Ca2+]i by releasing Ca2+ from buffer sites or intracellular stores, we examined in detail the effect of light and circulating current on [Ca2+]i by making simultaneous measurements of suction pipette current and [Ca2+]i from isolated rods of the salamander Ambystoma tigrinum after incorporation of the fluorescent dye fluo-5F. When the release of Ca2+ is measured in 0 Ca2+−0 Na+ solution, minimising fluxes of Ca2+ across the plasma membrane, it is substantial only for light bright enough to bleach a significant fraction of the photopigment and is restricted to the part of the outer segment in which the bleach occurred. It is unlikely, therefore, to make a large contribution to [Ca2+]i for most of the physiological operating range of the rod. Nevertheless, since release is half-maximal for a bleach of less than 10 %, it cannot be produced by a simple mechanism such as a change in the affinity of a binding site on rhodopsin itself but must instead require some more complex interaction. In Ringer solution, the Ca2+ in the light-releasable pool can be discharged merely by the decrease in [Ca2+]i that occurs as the outer segment channels close. In steady background light or after exposure to saturating illumination, the fraction of Ca2+ in the pool decreases essentially in proportion to [Ca2+]i as if Ca2+ were being removed from a buffer site within the cytoplasm. Furthermore, [Ca2+]i itself changes in proportion to the circulating current, with little evidence for a contribution from Ca2+ release or other mechanisms of Ca2+ homeostasis. This indicates that flux of Ca2+ across the plasma membrane is the major determinant of outer segment Ca2+ concentration within the rod's normal operating light intensity range. Once Ca2+ has been discharged from the releasable pool, it is restored following dim illumination apparently as the simple result of the subsequent restoration of dark [Ca2+]i and the rebinding of Ca2+ to its release site, but after brighter light perhaps also as a consequence of regeneration of the photopigment. PMID:12949220

Pyrometer mount for a closed-circuit thermal medium cooled gas turbine

DOEpatents

Jones, Raymond Joseph; Kirkpatrick, Francis Lawrence; Burns, James Lee; Fulton, John Robert

2002-01-01

A steam-cooled second-stage nozzle segment has an outer band and an outer cover defining a plenum therebetween for receiving cooling steam for flow through the nozzles to the inner band and cover therefor and return flow through the nozzles. To measure the temperature of the buckets of the stage forwardly of the nozzle stage, a pyrometer boss is electron beam-welded in an opening through the outer band and TIG-welded to the outer cover plate. By machining a hole through the boss and seating a linearly extending tube in the boss, a line of sight between a pyrometer mounted on the turbine frame and the buckets is provided whereby the temperature of the buckets can be ascertained. The welding of the boss to the outer band and outer cover enables steam flow through the plenum without leakage, while providing a line of sight through the outer cover and outer band to measure bucket temperature.

Inner and outer coronary vessel wall segmentation from CCTA using an active contour model with machine learning-based 3D voxel context-aware image force

NASA Astrophysics Data System (ADS)

Sivalingam, Udhayaraj; Wels, Michael; Rempfler, Markus; Grosskopf, Stefan; Suehling, Michael; Menze, Bjoern H.

2016-03-01

In this paper, we present a fully automated approach to coronary vessel segmentation, which involves calcification or soft plaque delineation in addition to accurate lumen delineation, from 3D Cardiac Computed Tomography Angiography data. Adequately virtualizing the coronary lumen plays a crucial role for simulating blood ow by means of fluid dynamics while additionally identifying the outer vessel wall in the case of arteriosclerosis is a prerequisite for further plaque compartment analysis. Our method is a hybrid approach complementing Active Contour Model-based segmentation with an external image force that relies on a Random Forest Regression model generated off-line. The regression model provides a strong estimate of the distance to the true vessel surface for every surface candidate point taking into account 3D wavelet-encoded contextual image features, which are aligned with the current surface hypothesis. The associated external image force is integrated in the objective function of the active contour model, such that the overall segmentation approach benefits from the advantages associated with snakes and from the ones associated with machine learning-based regression alike. This yields an integrated approach achieving competitive results on a publicly available benchmark data collection (Rotterdam segmentation challenge).

High sensitivity of contact-heat evoked potentials in "snake-eye" appearance myelopathy.

PubMed

Ulrich, A; Min, K; Curt, A

2015-10-01

To evaluate the sensitivity of dermatomal contact-heat evoked potentials (dCHEPs) compared to dermatomal somatosensory evoked potentials (dSSEPs) and clinical sensory testing in patients with focal central cord myelopathy, referred to as "snake-eye" appearance myelopathy (SEAM). 33 patients with SEAM in neuroimaging underwent electrophysiological (dCHEPs, dSSEPs) and clinical testing of sensory function (light touch [LT] and pin prick [PP]) at segments above, at and below to the spinal cord lesion. In total, 151 dermatomes were tested (39 above, 112 at/below lesion). The sensitivity of dCHEPs (97.0%) was significantly higher compared to dSSEPs (23.3%, p<0.001), PP (66.7%, p=0.003) and LT (69.7%, p=0.006), respectively. The sensitivity of dCHEPs was highest when applied one to two segments caudally to the level of spinal cord lesion in MRI. dCHEPs are highly sensitive and superior to dSSEPs and clinical sensory testing in the diagnosis of SEAM. dCHEPs may complement the diagnosis in focal central cord myelopathies where clinical testing of sensory function and dSSEPs are less sensitive to provide conclusive findings. Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Serial imaging and structure-function correlates of high-density rings of fundus autofluorescence in retinitis pigmentosa.

PubMed

Robson, Anthony G; Tufail, Adnan; Fitzke, Fred; Bird, Alan C; Moore, Anthony T; Holder, Graham E; Webster, Andrew R

2011-09-01

To document the evolution and functional and structural significance of parafoveal rings of high-density fundus autofluorescence (AF) in patients with retinitis pigmentosa and preserved visual acuity. Fifty-two patients with nonsyndromic retinitis pigmentosa or Usher syndrome, who had a parafoveal ring of high-density AF and a visual acuity of 20/30 or better, were ascertained. All had international standard full-field electroretinography and pattern electroretinography. Autofluorescence imaging was repeated in 30 patients after periods of up to 9.3 years. Of the 52 patients, 35 underwent optical coherence tomography. Progressive constriction of the ring was detected in 17 patients. Ring radius reduced by up to 40% at a mean rate of between 0.8% and 15.8% per year. In 1 patient, a small ring was replaced by irregular AF; visual acuity deteriorated over the same period. There was a high correspondence between the lateral extent of the preserved optical coherence tomography inner segment/outer segment band and the diameter of the ring along the same optical coherence tomographic scan plane (slope, 0.9; r = 0.97; P < 0.005; n = 35) and between preserved inner segment/outer segment lamina and the pattern electroretinography P50 measure of macular function (R = 0.72; P < 0.005; n = 34). Rings of increased AF surround areas of preserved outer retina and preserved photopic function. Serial fundus AF may provide prognostic indicators for preservation of central acuity and potentially assist in the identification and evaluation of patients suitable for treatment aimed at preservation of remaining function.

Improving image segmentation performance and quantitative analysis via a computer-aided grading methodology for optical coherence tomography retinal image analysis.

PubMed

Debuc, Delia Cabrera; Salinas, Harry M; Ranganathan, Sudarshan; Tátrai, Erika; Gao, Wei; Shen, Meixiao; Wang, Jianhua; Somfai, Gábor M; Puliafito, Carmen A

2010-01-01

We demonstrate quantitative analysis and error correction of optical coherence tomography (OCT) retinal images by using a custom-built, computer-aided grading methodology. A total of 60 Stratus OCT (Carl Zeiss Meditec, Dublin, California) B-scans collected from ten normal healthy eyes are analyzed by two independent graders. The average retinal thickness per macular region is compared with the automated Stratus OCT results. Intergrader and intragrader reproducibility is calculated by Bland-Altman plots of the mean difference between both gradings and by Pearson correlation coefficients. In addition, the correlation between Stratus OCT and our methodology-derived thickness is also presented. The mean thickness difference between Stratus OCT and our methodology is 6.53 microm and 26.71 microm when using the inner segment/outer segment (IS/OS) junction and outer segment/retinal pigment epithelium (OS/RPE) junction as the outer retinal border, respectively. Overall, the median of the thickness differences as a percentage of the mean thickness is less than 1% and 2% for the intragrader and intergrader reproducibility test, respectively. The measurement accuracy range of the OCT retinal image analysis (OCTRIMA) algorithm is between 0.27 and 1.47 microm and 0.6 and 1.76 microm for the intragrader and intergrader reproducibility tests, respectively. Pearson correlation coefficients demonstrate R(2)>0.98 for all Early Treatment Diabetic Retinopathy Study (ETDRS) regions. Our methodology facilitates a more robust and localized quantification of the retinal structure in normal healthy controls and patients with clinically significant intraretinal features.

Improving image segmentation performance and quantitative analysis via a computer-aided grading methodology for optical coherence tomography retinal image analysis

NASA Astrophysics Data System (ADS)

Cabrera Debuc, Delia; Salinas, Harry M.; Ranganathan, Sudarshan; Tátrai, Erika; Gao, Wei; Shen, Meixiao; Wang, Jianhua; Somfai, Gábor M.; Puliafito, Carmen A.

2010-07-01

We demonstrate quantitative analysis and error correction of optical coherence tomography (OCT) retinal images by using a custom-built, computer-aided grading methodology. A total of 60 Stratus OCT (Carl Zeiss Meditec, Dublin, California) B-scans collected from ten normal healthy eyes are analyzed by two independent graders. The average retinal thickness per macular region is compared with the automated Stratus OCT results. Intergrader and intragrader reproducibility is calculated by Bland-Altman plots of the mean difference between both gradings and by Pearson correlation coefficients. In addition, the correlation between Stratus OCT and our methodology-derived thickness is also presented. The mean thickness difference between Stratus OCT and our methodology is 6.53 μm and 26.71 μm when using the inner segment/outer segment (IS/OS) junction and outer segment/retinal pigment epithelium (OS/RPE) junction as the outer retinal border, respectively. Overall, the median of the thickness differences as a percentage of the mean thickness is less than 1% and 2% for the intragrader and intergrader reproducibility test, respectively. The measurement accuracy range of the OCT retinal image analysis (OCTRIMA) algorithm is between 0.27 and 1.47 μm and 0.6 and 1.76 μm for the intragrader and intergrader reproducibility tests, respectively. Pearson correlation coefficients demonstrate R2>0.98 for all Early Treatment Diabetic Retinopathy Study (ETDRS) regions. Our methodology facilitates a more robust and localized quantification of the retinal structure in normal healthy controls and patients with clinically significant intraretinal features.

Fully automated calculation of cardiothoracic ratio in digital chest radiographs

NASA Astrophysics Data System (ADS)

Cong, Lin; Jiang, Luan; Chen, Gang; Li, Qiang

2017-03-01

The calculation of Cardiothoracic Ratio (CTR) in digital chest radiographs would be useful for cardiac anomaly assessment and heart enlargement related disease indication. The purpose of this study was to develop and evaluate a fully automated scheme for calculation of CTR in digital chest radiographs. Our automated method consisted of three steps, i.e., lung region localization, lung segmentation, and CTR calculation. We manually annotated the lung boundary with 84 points in 100 digital chest radiographs, and calculated an average lung model for the subsequent work. Firstly, in order to localize the lung region, generalized Hough transform was employed to identify the upper, lower, and outer boundaries of lung by use of Sobel gradient information. The average lung model was aligned to the localized lung region to obtain the initial lung outline. Secondly, we separately applied dynamic programming method to detect the upper, lower, outer and inner boundaries of lungs, and then linked the four boundaries to segment the lungs. Based on the identified outer boundaries of left lung and right lung, we corrected the center and the declination of the original radiography. Finally, CTR was calculated as a ratio of the transverse diameter of the heart to the internal diameter of the chest, based on the segmented lungs. The preliminary results on 106 digital chest radiographs showed that the proposed method could obtain accurate segmentation of lung based on subjective observation, and achieved sensitivity of 88.9% (40 of 45 abnormalities), and specificity of 100% (i.e. 61 of 61 normal) for the identification of heart enlargements.

Contrast visual acuity in patients with retinitis pigmentosa assessed by a contrast sensitivity tester.

PubMed

Oishi, Maho; Nakamura, Hajime; Hangai, Masanori; Oishi, Akio; Otani, Atsushi; Yoshimura, Nagahisa

2012-01-01

To assess contrast visual acuity (CVA) in patients with retinitis pigmentosa (RP) and compare the result with standard visual acuity (VA), retinal thickness, status of inner segment/outer segment junction, and central visual field. Thirty-nine eyes of 39 patients with RP and 39 eyes of 39 healthy individuals were studied. To see the difference in CVA between RP patients and normal controls, only subjects with standard VA of 1.0 (20/20) or better were included. This was a cross-sectional study. CVA in various light conditions was measured with CAT-2000 and was compared between patients and controls. CVA of patients was further analyzed for association with other parameters including foveal retinal thickness, outer nuclear layer thickness, the status of inner segment/outer segment junction measured with optical coherence tomography (OCT), and visual field mean deviation (MD) measured with Humphrey field analyzer 10-2 program. CVA impairment was evident in RP patients compared to controls (P < 0.01, in all measurement conditions). Multivariate analysis showed association of logarithm of the minimum angle of resolution (logMAR) with CVAs in several conditions. None of the OCT measurements was associated with CVA. When patients were divided into three groups based on MD, the most advanced group (MD worse than or equal to -20 dB) showed impairment of mesopic CVA (P < 0.05, under mesopic condition of 100% without glare, with glare, and 25% without glare). CVA impairment was confirmed in RP patients, especially in advanced cases. CVA measured with CAT-2000 may be a useful tool for assessing foveal function in RP patients.

Identification of endogenous fluorophores in the photoreceptors using autofluorescence spectroscopy

NASA Astrophysics Data System (ADS)

Zhao, Lingling; Qu, Junle; Niu, Hanben

2007-11-01

In this paper, we present our investigation on the identification of endogenous fluorophores in photoreceptors using autofluorescence spectroscopy, which is performed with an inverted laser scanning confocal microscope equipped with an Argon ion laser and a GreNe laser. In our experiments, individual cones and rods are clearly resolved even in freshly prepared retina samples, without slicing or labeling. The experiment results show that autofluorescence spectrum of the photoreceptors has three peaks approximately at 525nm, 585nm and 665nm. Furthermore, the brightest autofluorescence originates from the photoreceptor outer segments. We can, therefore, come to a conclusion that the peaks at 525nm, 585nm are corresponding to FAD and A2-PE, respectively, which are distributed in the photoreceptor outer segments.

A semi-automatic computer-aided method for surgical template design

NASA Astrophysics Data System (ADS)

Chen, Xiaojun; Xu, Lu; Yang, Yue; Egger, Jan

2016-02-01

This paper presents a generalized integrated framework of semi-automatic surgical template design. Several algorithms were implemented including the mesh segmentation, offset surface generation, collision detection, ruled surface generation, etc., and a special software named TemDesigner was developed. With a simple user interface, a customized template can be semi- automatically designed according to the preoperative plan. Firstly, mesh segmentation with signed scalar of vertex is utilized to partition the inner surface from the input surface mesh based on the indicated point loop. Then, the offset surface of the inner surface is obtained through contouring the distance field of the inner surface, and segmented to generate the outer surface. Ruled surface is employed to connect inner and outer surfaces. Finally, drilling tubes are generated according to the preoperative plan through collision detection and merging. It has been applied to the template design for various kinds of surgeries, including oral implantology, cervical pedicle screw insertion, iliosacral screw insertion and osteotomy, demonstrating the efficiency, functionality and generality of our method.

A semi-automatic computer-aided method for surgical template design

PubMed Central

Chen, Xiaojun; Xu, Lu; Yang, Yue; Egger, Jan

2016-01-01

This paper presents a generalized integrated framework of semi-automatic surgical template design. Several algorithms were implemented including the mesh segmentation, offset surface generation, collision detection, ruled surface generation, etc., and a special software named TemDesigner was developed. With a simple user interface, a customized template can be semi- automatically designed according to the preoperative plan. Firstly, mesh segmentation with signed scalar of vertex is utilized to partition the inner surface from the input surface mesh based on the indicated point loop. Then, the offset surface of the inner surface is obtained through contouring the distance field of the inner surface, and segmented to generate the outer surface. Ruled surface is employed to connect inner and outer surfaces. Finally, drilling tubes are generated according to the preoperative plan through collision detection and merging. It has been applied to the template design for various kinds of surgeries, including oral implantology, cervical pedicle screw insertion, iliosacral screw insertion and osteotomy, demonstrating the efficiency, functionality and generality of our method. PMID:26843434

A semi-automatic computer-aided method for surgical template design.

PubMed

Chen, Xiaojun; Xu, Lu; Yang, Yue; Egger, Jan

2016-02-04

This paper presents a generalized integrated framework of semi-automatic surgical template design. Several algorithms were implemented including the mesh segmentation, offset surface generation, collision detection, ruled surface generation, etc., and a special software named TemDesigner was developed. With a simple user interface, a customized template can be semi- automatically designed according to the preoperative plan. Firstly, mesh segmentation with signed scalar of vertex is utilized to partition the inner surface from the input surface mesh based on the indicated point loop. Then, the offset surface of the inner surface is obtained through contouring the distance field of the inner surface, and segmented to generate the outer surface. Ruled surface is employed to connect inner and outer surfaces. Finally, drilling tubes are generated according to the preoperative plan through collision detection and merging. It has been applied to the template design for various kinds of surgeries, including oral implantology, cervical pedicle screw insertion, iliosacral screw insertion and osteotomy, demonstrating the efficiency, functionality and generality of our method.

A New Species of Hyperbenthic Cyclopoid Copepod from Japan: First Record of the Genus Cyclopicina in the Indo-Pacific Region.

PubMed

Ohtsuka, Susumu; Tanaka, Hayato; Boxshall, Geoffrey A

2016-12-01

A new species of the cyclopinid genus Cyclopicina, C. toyoshioae sp. nov., was collected from the hyperbenthic layer off northern Kyushu Island, Japan; its description is based on two adult female specimens. This is the first record of the genus from the Indo-Pacific region. The new species can be distinguished from its two known congeners in: (1) the relatively short antennules which do not reach the posterior margin of the dorsal cephalothoracic shield; (2) the shape of seminal receptacles; (3) the segmentation and armature of the cephalothoracic appendages; (4) the shape of the basal protrusion between the rami of legs 1-4; (5) the presence of three outer spines on the third exopodal segment of leg 4; and (6) the presence or absence of outer setae on the free exopodal segment of leg 5. The genus Cyclopicina shows a wide but scattered distribution in hyperbenthic layers, from the continental shelves to deep-sea basins, in the northern hemisphere.

Photoreceptor inner segment ellipsoid band integrity on spectral domain optical coherence tomography

PubMed Central

Saxena, Sandeep; Srivastav, Khushboo; Cheung, Chui M; Ng, Joanne YW; Lai, Timothy YY

2014-01-01

Spectral domain optical coherence tomography cross-sectional imaging of the macula has conventionally been resolved into four bands. However, some doubts were raised regarding authentication of the existence of these bands. Recently, a number of studies have suggested that the second band appeared to originate from the inner segment ellipsoids of the foveal cone photoreceptors, and therefore the previously called inner segment-outer segment junction is now referred to as inner segment ellipsoidband. Photoreceptor dysfunction may be a significant predictor of visual acuity in a spectrum of surgical and medical retinal diseases. This review aims to provide an overview and summarizes the role of the photoreceptor inner segment ellipsoid band in the management and prognostication of various vitreoretinal diseases. PMID:25525329

Shape-specific perceptual learning in a figure-ground segregation task.

PubMed

Yi, Do-Joon; Olson, Ingrid R; Chun, Marvin M

2006-03-01

What does perceptual experience contribute to figure-ground segregation? To study this question, we trained observers to search for symmetric dot patterns embedded in random dot backgrounds. Training improved shape segmentation, but learning did not completely transfer either to untrained locations or to untrained shapes. Such partial specificity persisted for a month after training. Interestingly, training on shapes in empty backgrounds did not help segmentation of the trained shapes in noisy backgrounds. Our results suggest that perceptual training increases the involvement of early sensory neurons in the segmentation of trained shapes, and that successful segmentation requires perceptual skills beyond shape recognition alone.

Multicenter reliability of semiautomatic retinal layer segmentation using OCT

PubMed Central

Oberwahrenbrock, Timm; Traber, Ghislaine L.; Lukas, Sebastian; Gabilondo, Iñigo; Nolan, Rachel; Songster, Christopher; Balk, Lisanne; Petzold, Axel; Paul, Friedemann; Villoslada, Pablo; Brandt, Alexander U.; Green, Ari J.

2018-01-01

Objective To evaluate the inter-rater reliability of semiautomated segmentation of spectral domain optical coherence tomography (OCT) macular volume scans. Methods Macular OCT volume scans of left eyes from 17 subjects (8 patients with MS and 9 healthy controls) were automatically segmented by Heidelberg Eye Explorer (v1.9.3.0) beta-software (Spectralis Viewing Module v6.0.0.7), followed by manual correction by 5 experienced operators from 5 different academic centers. The mean thicknesses within a 6-mm area around the fovea were computed for the retinal nerve fiber layer, ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer, outer plexiform layer (OPL), and outer nuclear layer (ONL). Intraclass correlation coefficients (ICCs) were calculated for mean layer thickness values. Spatial distribution of ICC values for the segmented volume scans was investigated using heat maps. Results Agreement between raters was good (ICC > 0.84) for all retinal layers, particularly inner retinal layers showed excellent agreement across raters (ICC > 0.96). Spatial distribution of ICC showed highest values in the perimacular area, whereas the ICCs were poorer for the foveola and the more peripheral macular area. The automated segmentation of the OPL and ONL required the most correction and showed the least agreement, whereas differences were less prominent for the remaining layers. Conclusions Automated segmentation with manual correction of macular OCT scans is highly reliable when performed by experienced raters and can thus be applied in multicenter settings. Reliability can be improved by restricting analysis to the perimacular area and compound segmentation of GCL and IPL. PMID:29552598

Why do children pay more attention to grammatical morphemes at the ends of sentences?

PubMed

Sundara, Megha

2018-05-01

Children pay more attention to the beginnings and ends of sentences rather than the middle. In natural speech, ends of sentences are prosodically and segmentally enhanced; they are also privileged by sensory and recall advantages. We contrasted whether acoustic enhancement or sensory and recall-related advantages are necessary and sufficient for the salience of grammatical morphemes at the ends of sentences. We measured 22-month-olds' listening times to grammatical and ungrammatical sentences with third person singular -s. Crucially, by cross-splicing the speech stimuli, acoustic enhancement and sensory and recall advantages were fully crossed. Only children presented with the verb in sentence-final position, a position with sensory and recall advantages, distinguished between the grammatical and ungrammatical sentences. Thus, sensory and recall advantages alone were necessary and sufficient to make grammatical morphemes at ends of sentences salient. These general processing constraints privilege ends of sentences over middles, regardless of the acoustic enhancement.

Reconstituted TOM core complex and Tim9/Tim10 complex of mitochondria are sufficient for translocation of the ADP/ATP carrier across membranes.

PubMed

Vasiljev, Andreja; Ahting, Uwe; Nargang, Frank E; Go, Nancy E; Habib, Shukry J; Kozany, Christian; Panneels, Valérie; Sinning, Irmgard; Prokisch, Holger; Neupert, Walter; Nussberger, Stephan; Rapaport, Doron

2004-03-01

Precursor proteins of the solute carrier family and of channel forming Tim components are imported into mitochondria in two main steps. First, they are translocated through the TOM complex in the outer membrane, a process assisted by the Tim9/Tim10 complex. They are passed on to the TIM22 complex, which facilitates their insertion into the inner membrane. In the present study, we have analyzed the function of the Tim9/Tim10 complex in the translocation of substrates across the outer membrane of mitochondria. The purified TOM core complex was reconstituted into lipid vesicles in which purified Tim9/Tim10 complex was entrapped. The precursor of the ADP/ATP carrier (AAC) was found to be translocated across the membrane of such lipid vesicles. Thus, these components are sufficient for translocation of AAC precursor across the outer membrane. Peptide libraries covering various substrate proteins were used to identify segments that are bound by Tim9/Tim10 complex upon translocation through the TOM complex. The patterns of binding sites on the substrate proteins suggest a mechanism by which portions of membrane-spanning segments together with flanking hydrophilic segments are recognized and bound by the Tim9/Tim10 complex as they emerge from the TOM complex into the intermembrane space.

Membrane curvature generation by a C-terminal amphipathic helix in peripherin-2/rds, a tetraspanin required for photoreceptor sensory cilium morphogenesis

PubMed Central

Khattree, Nidhi; Ritter, Linda M.; Goldberg, Andrew F. X.

2013-01-01

Summary Vertebrate vision requires photon absorption by photoreceptor outer segments (OSs), structurally elaborate membranous organelles derived from non-motile sensory cilia. The structure and function of OSs depends on a precise stacking of hundreds of membranous disks. Each disk is fully (as in rods) or partially (as in cones) bounded by a rim, at which the membrane is distorted into an energetically unfavorable high-curvature bend; however, the mechanism(s) underlying disk rim structure is (are) not established. Here, we demonstrate that the intrinsically disordered cytoplasmic C-terminus of the photoreceptor tetraspanin peripherin-2/rds (P/rds) can directly generate membrane curvature. A P/rds C-terminal domain and a peptide mimetic of an amphipathic helix contained within it each generated curvature in liposomes with a composition similar to that of OS disks and in liposomes generated from native OS lipids. Association of the C-terminal domain with liposomes required conical phospholipids, and was promoted by membrane curvature and anionic surface charge, results suggesting that the P/rds C-terminal amphipathic helix can partition into the cytosolic membrane leaflet to generate curvature by a hydrophobic insertion (wedging) mechanism. This activity was evidenced in full-length P/rds by its induction of small-diameter tubulovesicular membrane foci in cultured cells. In sum, the findings suggest that curvature generation by the P/rds C-terminus contributes to the distinctive structure of OS disk rims, and provide insight into how inherited defects in P/rds can disrupt organelle structure to cause retinal disease. They also raise the possibility that tethered amphipathic helices can function for shaping cellular membranes more generally. PMID:23886945

Turbine nozzle stage having thermocouple guide tube

DOEpatents

Schotsch, Margaret Jones; Kirkpatrick, Francis Lawrence; Lapine, Eric Michael

2002-01-01

A guide tube is fixed adjacent opposite ends in outer and inner covers of a nozzle stage segment. The guide tube is serpentine in shape between the outer and inner covers and extends through a nozzle vane. An insert is disposed in the nozzle vane and has apertures to accommodate serpentine portions of the guide tube. Cooling steam is also supplied through chambers of the insert on opposite sides of a central insert chamber containing the guide tube. The opposite ends of the guide tube are fixed to sleeves, in turn fixed to the outer and inner covers.

Calcium and magnesium fluxes across the plasma membrane of the toad rod outer segment.

PubMed Central

Nakatani, K; Yau, K W

1988-01-01

1. Membrane current was recorded from an isolated, dark-adapted toad rod by sucking either its inner segment or outer segment into a tight-fitting glass pipette containing Ringer solution. The remainder of the cell was exposed to bath solution which could be changed rapidly. 2. In normal Ringer solution the current response of a cell to a saturating flash or step of light showed a small secondary rise at its initial peak. The profile of this secondary rise (i.e. amplitude and time course) was independent of both the intensity and the duration of illumination once the light response had reached a plateau level. 3. This secondary rise disappeared when external Na+ around the outer segment was replaced by Li+ or guanidinium, suggesting that it represented an electrogenic Na+-dependent Ca2+ efflux which was declining after the onset of light. 4. This Na+-Ca2+ exchange activity showed a roughly exponential decline, with a time constant of about 0.5 s. Exponential extrapolation of the exchange current to the time at half-height of the light response gave an initial amplitude of about 2 pA. Using La3+ as a blocker, we did not detect any steady exchange current after the initial exponential decline. 5. An intense flash superposed on a just-saturating steady background light failed to produce any incremental exchange current transient. 6. Our interpretation of the above results is that in darkness there are counterbalancing levels of Ca2+ influx (through the light-sensitive conductance) and efflux (through the Na+-Ca2+ exchange) across the plasma membrane of the rod outer segment. The exchange current transient at the onset of light merely represents the unidirectional Ca2+ efflux which becomes revealed as a result of the stoppage of the Ca2+ influx, rather than a de novo Ca2+ efflux triggered by light. 7. Consistent with this interpretation, a test light delivered soon after a saturating, conditioning light elicited little exchange current, which then gradually recovered to control value with a time course parallel to the restoration of the dark current. Conversely, when the dark current was increased above its physiological level by IBMX (isobutylmethylxanthine) the exchange current transient became larger than control.(ABSTRACT TRUNCATED AT 400 WORDS) Images Fig. 8 PMID:2457685

Tissue-specific roles of Tbx1 in the development of the outer, middle and inner ear, defective in 22q11DS patients

PubMed Central

Arnold, Jelena S.; Braunstein, Evan M.; Ohyama, Takahiro; Groves, Andrew K.; Adams, Joe C.; Brown, M. Christian; Morrow, Bernice E.

2007-01-01

Most 22q11.2 deletion syndrome (22q11DS) patients have middle and outer ear anomalies, whereas some have inner ear malformations. Tbx1, a gene hemizygously deleted in 22q11DS patients and required for ear development, is expressed in multiple tissues during embryogenesis. To determine the role of Tbx1 in the first pharyngeal pouch (PPI) in forming outer and middle ears, we tissue-specifically inactivated the gene using Foxg1-Cre. In the conditional mutants, PPI failed to outgrow, preventing the middle ear bone condensations from forming. Tbx1 was also inactivated in the otic vesicle (OV), resulting in the failure of inner ear sensory organ formation, and in duplication of the cochleovestibular ganglion (CVG). Consistent with the anatomical defects, the sensory genes, Otx1 and Bmp4 were downregulated, whereas the CVG genes, Fgf3 and NeuroD, were upregulated. To delineate Tbx1 cell-autonomous roles, a more selective ablation, exclusively in the OV, was performed using Pax2-Cre. In contrast to the Foxg1-Cre mutants, Pax2-Cre conditional mutant mice survived to adulthood and had normal outer and middle ears but had the same inner ear defects as the Tbx1 null mice, with the same gene expression changes. These results demonstrate that Tbx1 has non-cell autonomous roles in PPI in the formation of outer and middle ears and cell-autonomous roles in the OV. Periotic mesenchymal markers, Prx2 and Brn4 were normal in both conditional mutants, whereas they were diminished in Tbx1−/− embryos. Thus, Tbx1 in the surrounding mesenchyme in both sets of conditional mutants cannot suppress the defects in the OV that occur in the null mutants. PMID:16600992

The Photosensitivity of Rhodopsin Bleaching and Light-Induced Increases of Fundus Reflectance in Mice Measured In Vivo With Scanning Laser Ophthalmoscopy

PubMed Central

Zhang, Pengfei; Goswami, Mayank; Zawadzki, Robert J.; Pugh, Edward N.

2016-01-01

Purpose To quantify bleaching-induced changes in fundus reflectance in the mouse retina. Methods Light reflected from the fundus of albino (Balb/c) and pigmented (C57Bl/6J) mice was measured with a multichannel scanning laser ophthalmoscopy optical coherence tomography (SLO-OCT) optical system. Serial scanning of small retinal regions was used for bleaching rhodopsin and measuring reflectance changes. Results Serial scanning generated a saturating reflectance increase centered at 501 nm with a photosensitivity of 1.4 × 10−8 per molecule μm2 in both strains, 2-fold higher than expected were irradiance at the rod outer segment base equal to that at the retinal surface. The action spectrum of the reflectance increase corresponds to the absorption spectrum of mouse rhodopsin in situ. Spectra obtained before and after bleaching were fitted with a model of fundus reflectance, quantifying contributions from loss of rhodopsin absorption with bleaching, absorption by oxygenated hemoglobin (HbO2) in the choroid (Balb/c), and absorption by melanin (C57Bl/6J). Both mouse strains exhibited light-induced broadband reflectance changes explained as bleaching-induced reflectivity increases at photoreceptor inner segment/outer segment (IS/OS) junctions and OS tips. Conclusions The elevated photosensitivity of rhodopsin bleaching in vivo is explained by waveguide condensing of light in propagation from rod inner segment (RIS) to rod outer segment (ROS). The similar photosensitivity of rhodopsin in the two strains reveals that little light backscattered from the sclera can enter the ROS. The bleaching-induced increases in reflectance at the IS/OS junctions and OS tips resemble results previously reported in human cones, but are ascribed to rods due to their 30/1 predominance over cones in mice and to the relatively minor amount of cone M-opsin in the regions scanned. PMID:27403994

Architecture of kangaroo rat inner medulla: segmentation of descending thin limb of Henle's loop.

PubMed

Urity, Vinoo B; Issaian, Tadeh; Braun, Eldon J; Dantzler, William H; Pannabecker, Thomas L

2012-03-15

We hypothesize that the inner medulla of the kangaroo rat Dipodomys merriami, a desert rodent that concentrates its urine to more than 6,000 mosmol/kgH(2)O water, provides unique examples of architectural features necessary for production of highly concentrated urine. To investigate this architecture, inner medullary nephron segments in the initial 3,000 μm below the outer medulla were assessed with digital reconstructions from physical tissue sections. Descending thin limbs of Henle (DTLs), ascending thin limbs of Henle (ATLs), and collecting ducts (CDs) were identified by immunofluorescence using antibodies that label segment-specific proteins associated with transepithelial water flux (aquaporin 1 and 2, AQP1 and AQP2) and chloride flux (the chloride channel ClC-K1); all tubules and vessels were labeled with wheat germ agglutinin. In the outer 3,000 μm of the inner medulla, AQP1-positive DTLs lie at the periphery of groups of CDs. ATLs lie inside and outside the groups of CDs. Immunohistochemistry and reconstructions of loops that form their bends in the outer 3,000 μm of the inner medulla show that, relative to loop length, the AQP1-positive segment of the kangaroo rat is significantly longer than that of the Munich-Wistar rat. The length of ClC-K1 expression in the prebend region at the terminal end of the descending side of the loop in kangaroo rat is about 50% shorter than that of the Munich-Wistar rat. Tubular fluid of the kangaroo rat DTL may approach osmotic equilibrium with interstitial fluid by water reabsorption along a relatively longer tubule length, compared with Munich-Wistar rat. A relatively shorter-length prebend segment may promote a steeper reabsorptive driving force at the loop bend. These structural features predict functionality that is potentially significant in the production of a high urine osmolality in the kangaroo rat.

Spanish, French and British consumers' acceptability of Uruguayan beef, and consumers' beef choice associated with country of origin, finishing diet and meat price.

PubMed

Realini, C E; Font i Furnols, M; Sañudo, C; Montossi, F; Oliver, M A; Guerrero, L

2013-09-01

The effect of country of origin (local, Switzerland, Argentina, Uruguay), finishing diet (grass, grass plus concentrate, concentrate), and price (low, medium, high) on consumer's beef choice and segmentation was evaluated in Spain, France and United Kingdom. Sensory acceptability of Uruguayan beef from different production systems was also evaluated and contrasted with consumers' beef choices. Origin was the most important characteristic for the choice of beef with preference for meat produced locally. The second most important factor was animal feed followed by price with preference for beef from grass-fed animals and lowest price. The least preferred product was beef from Uruguay, concentrate-fed animals and highest price. Sensory data showed higher acceptability scores for Uruguayan beef from grass-fed animals with or without concentrate supplementation than animals fed concentrate only. Consumer segments with distinct preferences were identified. Foreign country promotion seems to be fundamental for marketing beef in Europe, as well as the development of different marketing strategies to satisfy each consumer segment. Copyright © 2013 Elsevier Ltd. All rights reserved.

Protein sorting, targeting and trafficking in photoreceptor cells

PubMed Central

Pearring, Jillian N.; Salinas, Raquel Y.; Baker, Sheila A.; Arshavsky, Vadim Y.

2013-01-01

Vision is the most fundamental of our senses initiated when photons are absorbed by the rod and cone photoreceptor neurons of the retina. At the distal end of each photoreceptor resides a light-sensing organelle, called the outer segment, which is a modified primary cilium highly enriched with proteins involved in visual signal transduction. At the proximal end, each photoreceptor has a synaptic terminal, which connects this cell to the downstream neurons for further processing of the visual information. Understanding the mechanisms involved in creating and maintaining functional compartmentalization of photoreceptor cells remains among the most fascinating topics in ocular cell biology. This review will discuss how photoreceptor compartmentalization is supported by protein sorting, targeting and trafficking, with an emphasis on the best-studied cases of outer segment-resident proteins. PMID:23562855

Macular telangiectasia type 2 (MacTel) in a 34-year-old patient.

PubMed

Nicolai, Heleen; Wirix, Mieke; Spielberg, Leigh; Leys, Anita

2014-09-23

We report macular telangiectasia type 2 (MacTel) in a 34-year-old man, the youngest patient so far published with MacTel type 2. The patient presented with metamorphopsia and impaired reading ability. Diagnosis was based on bilateral abnormal macular autofluorescence, perifoveal telangiectasia with fluorescein angiographic hyperfluorescence without cystoid oedema, a small foveal avascular zone, asymmetric configuration of the foveal pit, disruptions in the inner segment/outer segment layer and hyper-reflective haze and spots in the outer nuclear layer. Although MacTel usually manifests with a slowly progressive decrease in visual acuity in the fifth to seventh decades of life, younger patients may occasionally be diagnosed with the disease. Awareness of subtle signs of the condition is essential for early diagnosis. 2014 BMJ Publishing Group Ltd.

Macular telangiectasia type 2 (MacTel) in a 34-year-old patient

PubMed Central

Nicolai, Heleen; Wirix, Mieke; Spielberg, Leigh; Leys, Anita

2014-01-01

We report macular telangiectasia type 2 (MacTel) in a 34-year-old man, the youngest patient so far published with MacTel type 2. The patient presented with metamorphopsia and impaired reading ability. Diagnosis was based on bilateral abnormal macular autofluorescence, perifoveal telangiectasia with fluorescein angiographic hyperfluorescence without cystoid oedema, a small foveal avascular zone, asymmetric configuration of the foveal pit, disruptions in the inner segment/outer segment layer and hyper-reflective haze and spots in the outer nuclear layer. Although MacTel usually manifests with a slowly progressive decrease in visual acuity in the fifth to seventh decades of life, younger patients may occasionally be diagnosed with the disease. Awareness of subtle signs of the condition is essential for early diagnosis. PMID:25249218

A perspective of gene therapy in the glaucomas.

PubMed

Kaufman, P L; Jia, W W; Tan, J; Chen, Z; Gabelt, B T; Booth, V; Tufaro, F; Cynader, M

1999-06-01

Gene therapy in the anterior and posterior segment tissues may have the potential to favorably influence aqueous hydrodynamics and retinal ganglion cell biology, thereby preventing, delaying, or minimizing glaucomatous damage to the optic nerve. We demonstrated the feasibility of using a herpes viral vector (ribonucleotide reductase defective HSV-1, hrR3) to deliver the lacZ reporter gene to living cat and rat eyes. Cats received injections into the anterior chamber and rats into the vitreous cavity. In cats, lacZ expression was detectable at 1 to 2 days in the anterior outer portion of the ciliary muscle and the lining of the intertrabecular spaces of the corneoscleral and uveal meshwork. Rat eyes showed lacZ expression in the retinal pigment epithelium and photoreceptor outer segments 2 days after injection.

Sensory properties and consumer acceptance of imported and domestic sliced black ripe olives.

PubMed

Lee, Soh Min; Kitsawad, Kamolnate; Sigal, Abdulkadir; Flynn, Dan; Guinard, Jean-Xavier

2012-12-01

Table olives are healthy and nutritious products with high contents of monounsaturated fatty acids, phenolics, vitamins, minerals, and fiber. Understanding sensory cues affecting consumer preferences would enable the increase of olive consumption. The objectives of this study were to characterize the sensory properties of commercial sliced black ripe olives from different regions, including California, Egypt, Morocco, Portugal, and Spain, and to examine the preferences of California consumers for sliced black ripe olives. Sensory profiles and preferences for 20 sliced olive samples were determined using descriptive analysis with a trained panel and a consumer test with 104 users and likers of table olives. Aroma and flavor characteristics separated the olives according to country of origin, and were the main determinants of consumer preferences for sliced olives, even though the biggest differences among the samples were in appearance and texture. Total of 2 consumer segments were identified with 51 and 53 consumers, respectively, that both liked Californian products, but differed in the olives they disliked. Negative drivers of liking for both segments included alcohol, oak barrel, and artificial fruity/floral characteristics; however, consumers from Cluster 1 were further negatively influenced by rancid, gassy, and bitter characteristics. This study stresses the need for sound and appealing flavor quality for table olives to gain wider acceptance among U.S. consumers. © 2012 Institute of Food Technologists®

Sensory properties and consumer acceptance of sweet tamarind varieties grown in Thailand.

PubMed

Oupadissakoon, Chintana; Chambers, Edgar; Kongpensook, Varapha; Suwonsichon, Suntaree; Yenket, Renoo; Retiveau, Annlyse

2010-04-30

Sweet tamarind is a major edible fruit and flavoring ingredient particularly in south-east and southern Asia. Little research has focused on the fruit and almost nothing is known of its particular sensory properties. The aims of this research were to develop a lexicon for describing sweet tamarind, to compare varieties grown in Thailand, determine if orchard impacts sensory properties, and determine consumer acceptance of the varieties. A descriptive sensory lexicon of 25 terms was developed and six varieties were grouped into three clusters based on their sensory properties. The clusters appear to represent varieties that differ in their dark fruity notes and firm, fibrous texture. Generally, the orchard in which the plants were grown had little effect on sensory properties. In general, Sithong was liked by consumers along with Kunthee and Pragaithong. Intapalum was liked less but one small segment of consumers disliked Sithong and liked the Intapalum variety more. This research provides a foundation for further sensory and consumer research on sweet tamarind varieties by providing the initial data on the sensory properties of sweet tamarind, a lexicon that can be used for future research, and information on the consumer acceptance of tamarind varieties.

Identification of the two rotavirus genes determining neutralization specificities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Offit, P.A.; Blavat, G.

1986-01-01

Bovine rotavirus NCDV and simian rotavirus SA-11 represent two distinct rotavirus serotypes. A genetic approach was used to determine which viral gene segments segregated with serotype-specific viral neutralization. There were 16 reassortant rotarviruses derived by coinfection of MA-104 cells in vitro with the SA-11 and NCDV strains. The parental origin of reassortant rotavirus double-stranded RNA segments was determined by gene segment mobility in polyacrylamide gels and by hybridization with radioactively labeled parental viral transcripts. The authors found that two rotavirus gene segments found previously to code for outer capsid proteins vp3 and vp7 cosegreated with virus neutralization specificities.

Noise-Induced Loss of Hair Cells and Cochlear Synaptopathy Are Mediated by the Activation of AMPK

PubMed Central

Hill, Kayla; Yuan, Hu; Wang, Xianren

2016-01-01

Noise-induced hearing loss (NIHL) is a major unresolved public health problem. Here, we investigate pathomechanisms of sensory hair cell death and suggest a novel target for protective intervention. Cellular survival depends upon maintenance of energy homeostasis, largely by AMP-activated protein kinase (AMPK). In response to a noise exposure in CBA/J mice, the levels of phosphorylated AMPKα increased in hair cells in a noise intensity-dependent manner. Inhibition of AMPK via siRNA or the pharmacological inhibitor compound C attenuated noise-induced loss of outer hair cells (OHCs) and synaptic ribbons, and preserved auditory function. Additionally, noise exposure increased the activity of the upstream AMPK kinase liver kinase B1 (LKB1) in cochlear tissues. The inhibition of LKB1 by siRNA attenuated the noise-increased phosphorylation of AMPKα in OHCs, reduced the loss of inner hair cell synaptic ribbons and OHCs, and protected against NIHL. These results indicate that noise exposure induces hair cell death and synaptopathy by activating AMPK via LKB1-mediated pathways. Targeting these pathways may provide a novel route to prevent NIHL. SIGNIFICANCE STATEMENT Our results demonstrate for the first time that the activation of AMP-activated protein kinase (AMPK) α in sensory hair cells is noise intensity dependent and contributes to noise-induced hearing loss by mediating the loss of inner hair cell synaptic ribbons and outer hair cells. Noise induces the phosphorylation of AMPKα1 by liver kinase B1 (LKB1), triggered by changes in intracellular ATP levels. The inhibition of AMPK activation by silencing AMPK or LKB1, or with the pharmacological inhibitor compound C, reduced outer hair cell and synaptic ribbon loss as well as noise-induced hearing loss. This study provides new insights into mechanisms of noise-induced hearing loss and suggests novel interventions for the prevention of the loss of sensory hair cells and cochlear synaptopathy. PMID:27413159

Sox10 Expressing Cells in the Lateral Wall of the Aged Mouse and Human Cochlea

PubMed Central

Hao, Xinping; Xing, Yazhi; Moore, Michael W.; Zhang, Jianning; Han, Demin; Schulte, Bradley A.; Dubno, Judy R.; Lang, Hainan

2014-01-01

Age-related hearing loss (presbycusis) is a common human disorder, affecting one in three Americans aged 60 and over. Previous studies have shown that presbyacusis is associated with a loss of non-sensory cells in the cochlear lateral wall. Sox10 is a transcription factor crucial to the development and maintenance of neural crest-derived cells including some non-sensory cell types in the cochlea. Mutations of the Sox10 gene are known to cause various combinations of hearing loss and pigmentation defects in humans. This study investigated the potential relationship between Sox10 gene expression and pathological changes in the cochlear lateral wall of aged CBA/CaJ mice and human temporal bones from older donors. Cochlear tissues prepared from young adult (1–3 month-old) and aged (2–2.5 year-old) mice, and human temporal bone donors were examined using quantitative immunohistochemical analysis and transmission electron microscopy. Cells expressing Sox10 were present in the stria vascularis, outer sulcus and spiral prominence in mouse and human cochleas. The Sox10+ cell types included marginal and intermediate cells and outer sulcus cells, including those that border the scala media and those extending into root processes (root cells) in the spiral ligament. Quantitative analysis of immunostaining revealed a significant decrease in the number of Sox10+ marginal cells and outer sulcus cells in aged mice. Electron microscopic evaluation revealed degenerative alterations in the surviving Sox10+ cells in aged mice. Strial marginal cells in human cochleas from donors aged 87 and older showed only weak immunostaining for Sox10. Decreases in Sox10 expression levels and a loss of Sox10+ cells in both mouse and human aged ears suggests an important role of Sox10 in the maintenance of structural and functional integrity of the lateral wall. A loss of Sox10+ cells may also be associated with a decline in the repair capabilities of non-sensory cells in the aged ear. PMID:24887110

Relationship between photoreceptor outer segment length and visual acuity in diabetic macular edema.

PubMed

Forooghian, Farzin; Stetson, Paul F; Meyer, Scott A; Chew, Emily Y; Wong, Wai T; Cukras, Catherine; Meyerle, Catherine B; Ferris, Frederick L

2010-01-01

The purpose of this study was to quantify photoreceptor outer segment (PROS) length in 27 consecutive patients (30 eyes) with diabetic macular edema using spectral domain optical coherence tomography and to describe the correlation between PROS length and visual acuity. Three spectral domain-optical coherence tomography scans were performed on all eyes during each session using Cirrus HD-OCT. A prototype algorithm was developed for quantitative assessment of PROS length. Retinal thicknesses and PROS lengths were calculated for 3 parameters: macular grid (6 x 6 mm), central subfield (1 mm), and center foveal point (0.33 mm). Intrasession repeatability was assessed using coefficient of variation and intraclass correlation coefficient. The association between retinal thickness and PROS length with visual acuity was assessed using linear regression and Pearson correlation analyses. The main outcome measures include intrasession repeatability of macular parameters and correlation of these parameters with visual acuity. Mean retinal thickness and PROS length were 298 mum to 381 microm and 30 microm to 32 mum, respectively, for macular parameters assessed in this study. Coefficient of variation values were 0.75% to 4.13% for retinal thickness and 1.97% to 14.01% for PROS length. Intraclass correlation coefficient values were 0.96 to 0.99 and 0.73 to 0.98 for retinal thickness and PROS length, respectively. Slopes from linear regression analyses assessing the association of retinal thickness and visual acuity were not significantly different from 0 (P > 0.20), whereas the slopes of PROS length and visual acuity were significantly different from 0 (P < 0.0005). Correlation coefficients for macular thickness and visual acuity ranged from 0.13 to 0.22, whereas coefficients for PROS length and visual acuity ranged from -0.61 to -0.81. Photoreceptor outer segment length can be quantitatively assessed using Cirrus HD-OCT. Although the intrasession repeatability of PROS measurements was less than that of macular thickness measurements, the stronger correlation of PROS length with visual acuity suggests that the PROS measures may be more directly related to visual function. Photoreceptor outer segment length may be a useful physiologic outcome measure, both clinically and as a direct assessment of treatment effects.

Characterization of photoreceptor degeneration in the rhodopsin P23H transgenic rat line 2 using optical coherence tomography.

PubMed

Monai, Natsuki; Yamauchi, Kodai; Tanabu, Reiko; Gonome, Takayuki; Ishiguro, Sei-Ichi; Nakazawa, Mitsuru

2018-01-01

To characterize the optical coherence tomography (OCT) appearances of photoreceptor degeneration in the rhodopsin P23H transgenic rat (line 2) in relation to the histological, ultrastructural, and electroretinography (ERG) findings. Homozygous rhodopsin P23H transgenic albino rats (line 2, very-slow degeneration model) were employed. Using OCT (Micron IV®; Phoenix Research Labs, Pleasanton, CA, USA), the natural course of photoreceptor degeneration was recorded from postnatal day (P) 15 to P 287. The OCT images were qualitatively observed by comparing them to histological and ultrastructural findings at P 62 and P 169. In addition, each retinal layer was quantitatively analyzed longitudinally during degeneration, compared it to that observed in wild type Sprague-Dawley (SD) rats. The relationships between the ERG (full-field combined rod-cone response, 3.0 cds/m2 stimulation) findings and OCT images were also analyzed. In the qualitative study, the two layers presumably corresponding to the photoreceptor inner segment ellipsoid zone (EZ) and interdigitation zone (IZ) were identified in the P23H rat until PN day 32. However, the photoreceptor inner and outer segment (IS/OS) layer became diffusely hyperreflective on OCT after P 46, and the EZ and IZ zones could no longer be identified on OCT. In contrast, in the SD rats, the EZ and IZ were clearly distinguished until at least P 247. The ultrastructural study showed partial disarrangements of the photoreceptor outer segment discs in the P23H rats at P 62, although a light-microscopic histological study detected almost no abnormality in the outer segment. In the quantitative study, the outer retinal layer including the outer plexiform layer (OPL) and the outer nuclear layer (ONL) became significantly thinner in the P23H rats than in the SD rats after P 71. The thickness of the IS/OS layer was maintained in the P23H rats until P 130, and it became statistically thinner than in the SD rats at P 237. The longitudinal attenuation in the amplitude of the a- and b-waves of ERG was significantly correlated with the thickness of the combined OPL and ONL but not with that of the IS/OS layer. OCT showed the degenerated photoreceptor IS/OS layer in rhodopsin P23H transgenic rats (line 2) as a diffuse hyperreflective zone, even in the early stage, with the partially disarranged and destabilized OS discs recognizable by ultrastructural assessment but not by a histological study. The amplitude of the a- and b-waves mainly depends on the thickness of the OPL and ONL layer rather than the thickness of the photoreceptor IS/OS layer in P23H rats.

Automatic segmentation and reconstruction of the cortex from neonatal MRI.

PubMed

Xue, Hui; Srinivasan, Latha; Jiang, Shuzhou; Rutherford, Mary; Edwards, A David; Rueckert, Daniel; Hajnal, Joseph V

2007-11-15

Segmentation and reconstruction of cortical surfaces from magnetic resonance (MR) images are more challenging for developing neonates than adults. This is mainly due to the dynamic changes in the contrast between gray matter (GM) and white matter (WM) in both T1- and T2-weighted images (T1w and T2w) during brain maturation. In particular in neonatal T2w images WM typically has higher signal intensity than GM. This causes mislabeled voxels during cortical segmentation, especially in the cortical regions of the brain and in particular at the interface between GM and cerebrospinal fluid (CSF). We propose an automatic segmentation algorithm detecting these mislabeled voxels and correcting errors caused by partial volume effects. Our results show that the proposed algorithm corrects errors in the segmentation of both GM and WM compared to the classic expectation maximization (EM) scheme. Quantitative validation against manual segmentation demonstrates good performance (the mean Dice value: 0.758+/-0.037 for GM and 0.794+/-0.078 for WM). The inner, central and outer cortical surfaces are then reconstructed using implicit surface evolution. A landmark study is performed to verify the accuracy of the reconstructed cortex (the mean surface reconstruction error: 0.73 mm for inner surface and 0.63 mm for the outer). Both segmentation and reconstruction have been tested on 25 neonates with the gestational ages ranging from approximately 27 to 45 weeks. This preliminary analysis confirms previous findings that cortical surface area and curvature increase with age, and that surface area scales to cerebral volume according to a power law, while cortical thickness is not related to age or brain growth.

Platform-Independent Cirrus and Spectralis Thickness Measurements in Eyes with Diabetic Macular Edema Using Fully Automated Software

PubMed Central

Willoughby, Alex S.; Chiu, Stephanie J.; Silverman, Rachel K.; Farsiu, Sina; Bailey, Clare; Wiley, Henry E.; Ferris, Frederick L.; Jaffe, Glenn J.

2017-01-01

Purpose We determine whether the automated segmentation software, Duke Optical Coherence Tomography Retinal Analysis Program (DOCTRAP), can measure, in a platform-independent manner, retinal thickness on Cirrus and Spectralis spectral domain optical coherence tomography (SD-OCT) images in eyes with diabetic macular edema (DME) under treatment in a clinical trial. Methods Automatic segmentation software was used to segment the internal limiting membrane (ILM), inner retinal pigment epithelium (RPE), and Bruch's membrane (BM) in SD-OCT images acquired by Cirrus and Spectralis commercial systems, from the same eye, on the same day during a clinical interventional DME trial. Mean retinal thickness differences were compared across commercial and DOCTRAP platforms using intraclass correlation (ICC) and Bland-Altman plots. Results The mean 1 mm central subfield thickness difference (standard error [SE]) comparing segmentation of Spectralis images with DOCTRAP versus HEYEX was 0.7 (0.3) μm (0.2 pixels). The corresponding values comparing segmentation of Cirrus images with DOCTRAP versus Cirrus software was 2.2 (0.7) μm. The mean 1 mm central subfield thickness difference (SE) comparing segmentation of Cirrus and Spectralis scan pairs with DOCTRAP using BM as the outer retinal boundary was −2.3 (0.9) μm compared to 2.8 (0.9) μm with inner RPE as the outer boundary. Conclusions DOCTRAP segmentation of Cirrus and Spectralis images produces validated thickness measurements that are very similar to each other, and very similar to the values generated by the corresponding commercial software in eyes with treated DME. Translational Relevance This software enables automatic total retinal thickness measurements across two OCT platforms, a process that is impractical to perform manually. PMID:28180033

A segmental chronic pain syndrome in rats associated with intrathecal infusion of NMDA: evidence for selective action in the dorsal horn.

PubMed

Zochodne, D W; Murray, M; Nag, S; Riopelle, R J

1994-02-01

We explored the effects of chronic lumbar intrathecal NMDA infusion (mini-osmotic pumps) in Sprague-Dawley rats on motor and sensory axon integrity. Several different infusion protocols, each given over a 4 week period were examined: 0.15 M NMDA in phosphate buffered saline; phosphate buffered saline without NMDA; and 0.20 M magnesium sulfate plus 0.15 M NMDA; 0.35 M NMDA. In two additional protocols, 0.15 M NMDA or phosphate buffered saline were infused for a total of 8 weeks. Within 1-2 weeks of the onset of NMDA, but not phosphate buffered saline infusions, the rats exhibited irritability, circling, biting and excessive grooming resulting in loss of hair, and skin ulcerations from autotomy localized to lumbar and sacral innervated dermatomes. Co-infusion of NMDA with magnesium sulfate almost completely prevented these findings. The behavioural changes were not associated with abnormalities of sensory or motor conduction. Intrathecal infusion of NMDA induces a chronic "central" experimental pain disorder in rats, localized to the cord segment with the greatest exposure to the infusion, without involvement of peripheral sensory axons and sparing the axonal integrity of anterior horn cells.

The phototransduction machinery in the rod outer segment has a strong efficacy gradient

PubMed Central

Mazzolini, Monica; Facchetti, Giuseppe; Andolfi, Laura; Proietti Zaccaria, Remo; Tuccio, Salvatore; Treu, Johannes; Altafini, Claudio; Di Fabrizio, Enzo M.; Lazzarino, Marco; Rapp, Gert; Torre, Vincent

2015-01-01

Rod photoreceptors consist of an outer segment (OS) and an inner segment. Inside the OS a biochemical machinery transforms the rhodopsin photoisomerization into electrical signal. This machinery has been treated as and is thought to be homogenous with marginal inhomogeneities. To verify this assumption, we developed a methodology based on special tapered optical fibers (TOFs) to deliver highly localized light stimulations. By using these TOFs, specific regions of the rod OS could be stimulated with spots of light highly confined in space. As the TOF is moved from the OS base toward its tip, the amplitude of saturating and single photon responses decreases, demonstrating that the efficacy of the transduction machinery is not uniform and is 5–10 times higher at the base than at the tip. This gradient of efficacy of the transduction machinery is attributed to a progressive depletion of the phosphodiesterase along the rod OS. Moreover we demonstrate that, using restricted spots of light, the duration of the photoresponse along the OS does not increase linearly with the light intensity as with diffuse light. PMID:25941368

Drive system for the retraction/extension of variable diameter rotor systems

NASA Technical Reports Server (NTRS)

Gmirya, Yuriy (Inventor)

2003-01-01

A drive system for a variable diameter rotor (VDR) system includes a plurality of rotor blade assemblies with inner and outer rotor blade segments. The outer blade segment being telescopically mounted to the inner blade segment. The VDR retraction/extension system includes a drive housing mounted at the root of each blade. The housing supports a spool assembly, a harmonic gear set and an electric motor. The spool assembly includes a pair of counter rotating spools each of which drive a respective cable which extends through the interior of the inboard rotor blade section and around a pulley mounted to the outboard rotor blade section. In operation, the electric motor drives the harmonic gear set which rotates the counter rotating spools. Rotation of the spools causes the cables to be wound onto or off their respective spool consequently effecting retraction/extension of the pulley and the attached outboard rotor blade section relative the inboard rotor blade section. As each blade drive system is independently driven by a separate electrical motor, each independent VDR blade assembly is independently positionable.

Pineal organs of deep-sea fish: photopigments and structure.

PubMed

Bowmaker, James K; Wagner, Hans-Joachim

2004-06-01

We have examined the morphology and photopigments of the pineal organs from a number of mesopelagic fish, including representatives of the hatchet fish (Sternoptychidae), scaly dragon-fish (Chauliodontidae) and bristlemouths (Gonostomidae). Although these fish were caught at depths of between 500 and 1000 m, the morphological organisation of their pineal organs is remarkably similar to that of surface-dwelling fish. Photoreceptor inner and outer segments protrude into the lumen of the pineal vesicle, and the outer segment is composed of a stack of up to 20 curved disks that form a cap-like cover over the inner segment. In all species, the pineal photopigment was spectrally distinct from the retinal rod pigment, with lambdamax displaced to longer wavelengths, between approximately 485 and 503 nm. We also investigated the pineal organ of the deep demersal eel, Synaphobranchus kaupi, caught at depths below 2000 m, which possesses a rod visual pigment with lambdamax at 478 nm, but the pineal pigment has lambdamax at approximately 515 nm. In one species of hatchet fish, Argyropelecus affinis, two spectral classes of pinealocyte were identified, both spectrally distinct from the retinal rod photopigment.

Retinal degeneration in cats fed casein. IV. The early receptor potential.

PubMed

Berson, E L; Watson, G; Grasse, K L; Szamier, R B

1981-08-01

Electroretinographic studies of casein-fed cats with retinal taurine deficiency revealed that the early receptor potential (ERP) was initially normal in amplitude at a time when the a-wave and b-wave of the electroretinogram were substantially reduced or even nondetectable. The preserved ERP's in these taurine-deficient cats could be correlated with the histologic finding that their outer segments were relatively intact over 90% of the retinal area subtended by the test flash. The sequence of electroretinographic changes in these taurine-deficient cats was also consistent with previous biochemical studies on the normal cat retina that have shown a relatively low concentration of taurine at the level of the outer segments and a higher concentration at the level of the inner segments. The responses in early stages from taurine-deficient cats differed from the responses obtained from vitamin A--deficient cats but resembled those from cats that received an intravitreal injection of ouabain. Similarities and a difference between the responses of taurine-deficient cats and those of patients with early retinitis pigmentosa are considered.

Rhodopsin expression in the zebrafish pineal gland from larval to adult stage.

PubMed

Magnoli, Domenico; Zichichi, Rosalia; Laurà, Rosaria; Guerrera, Maria Cristina; Campo, Salvatore; de Carlos, Felix; Suárez, Alberto Álvarez; Abbate, Francesco; Ciriaco, Emilia; Vega, Jose Antonio; Germanà, Antonino

2012-03-09

The zebrafish pineal gland plays an important role in different physiological functions including the regulation of the circadian clock. In the fish pineal gland the pinealocytes are made up of different segments: outer segment, inner segment and basal pole. Particularly, in the outer segment the rhodopsin participates in the external environment light reception that represents the first biochemical step in the melatonin production. It is well known that the rhodopsin in the adult zebrafish is well expressed in the pineal gland but both the expression and the cellular localization of this protein during development remain still unclear. In this study using qRT-PCR, sequencing and immunohistochemistry the expression as well as the protein localization of the rhodopsin in the zebrafish from larval (10 dpf) to adult stage (90 dpf) were demonstrated. The rhodopsin mRNA expression presents a peak of expression at 10 dpf, a further reduction to 50 dpf before increasing again in the adult stage. Moreover, the cellular localization of the rhodopsin-like protein was always localized in the pinealocyte at all ages examined. Our results demonstrated the involvement of the rhodopsin in the zebrafish pineal gland physiology particularly in the light capture during the zebrafish lifespan. Copyright © 2012 Elsevier B.V. All rights reserved.

Element for use in an inductive coupler for downhole components

DOEpatents

Hall, David R [Provo, UT; Fox, Joe [Spanish Fork, UT

2009-03-31

An element for use in an inductive coupler for downhole components comprises an annular housing having a generally circular recess. The element further comprises a plurality of generally linear, magnetically conductive segments. Each segment includes a bottom portion, an inner wall portion, and an outer wall portion. The portions together define a generally linear trough from a first end to a second end of each segment. The segments are arranged adjacent to each other within the housing recess to form a generally circular trough. The ends of at least half of the segments are shaped such that the first end of one of the segments is complementary in form to the second end of an adjacent segment. In one embodiment, all of the ends are angled. Preferably, the first ends are angled with the same angle and the second ends are angled with the complementary angle.

Learning-based automated segmentation of the carotid artery vessel wall in dual-sequence MRI using subdivision surface fitting.

PubMed

Gao, Shan; van 't Klooster, Ronald; Kitslaar, Pieter H; Coolen, Bram F; van den Berg, Alexandra M; Smits, Loek P; Shahzad, Rahil; Shamonin, Denis P; de Koning, Patrick J H; Nederveen, Aart J; van der Geest, Rob J

2017-10-01

The quantification of vessel wall morphology and plaque burden requires vessel segmentation, which is generally performed by manual delineations. The purpose of our work is to develop and evaluate a new 3D model-based approach for carotid artery wall segmentation from dual-sequence MRI. The proposed method segments the lumen and outer wall surfaces including the bifurcation region by fitting a subdivision surface constructed hierarchical-tree model to the image data. In particular, a hybrid segmentation which combines deformable model fitting with boundary classification was applied to extract the lumen surface. The 3D model ensures the correct shape and topology of the carotid artery, while the boundary classification uses combined image information of 3D TOF-MRA and 3D BB-MRI to promote accurate delineation of the lumen boundaries. The proposed algorithm was validated on 25 subjects (48 arteries) including both healthy volunteers and atherosclerotic patients with 30% to 70% carotid stenosis. For both lumen and outer wall border detection, our result shows good agreement between manually and automatically determined contours, with contour-to-contour distance less than 1 pixel as well as Dice overlap greater than 0.87 at all different carotid artery sections. The presented 3D segmentation technique has demonstrated the capability of providing vessel wall delineation for 3D carotid MRI data with high accuracy and limited user interaction. This brings benefits to large-scale patient studies for assessing the effect of pharmacological treatment of atherosclerosis by reducing image analysis time and bias between human observers. © 2017 American Association of Physicists in Medicine.

Segmentation of the common carotid artery with active shape models from 3D ultrasound images

NASA Astrophysics Data System (ADS)

Yang, Xin; Jin, Jiaoying; He, Wanji; Yuchi, Ming; Ding, Mingyue

2012-03-01

Carotid atherosclerosis is a major cause of stroke, a leading cause of death and disability. In this paper, we develop and evaluate a new segmentation method for outlining both lumen and adventitia (inner and outer walls) of common carotid artery (CCA) from three-dimensional ultrasound (3D US) images for carotid atherosclerosis diagnosis and evaluation. The data set consists of sixty-eight, 17× 2× 2, 3D US volume data acquired from the left and right carotid arteries of seventeen patients (eight treated with 80mg atorvastain and nine with placebo), who had carotid stenosis of 60% or more, at baseline and after three months of treatment. We investigate the use of Active Shape Models (ASMs) to segment CCA inner and outer walls after statin therapy. The proposed method was evaluated with respect to expert manually outlined boundaries as a surrogate for ground truth. For the lumen and adventitia segmentations, respectively, the algorithm yielded Dice Similarity Coefficient (DSC) of 93.6%+/- 2.6%, 91.8%+/- 3.5%, mean absolute distances (MAD) of 0.28+/- 0.17mm and 0.34 +/- 0.19mm, maximum absolute distances (MAXD) of 0.87 +/- 0.37mm and 0.74 +/- 0.49mm. The proposed algorithm took 4.4 +/- 0.6min to segment a single 3D US images, compared to 11.7+/-1.2min for manual segmentation. Therefore, the method would promote the translation of carotid 3D US to clinical care for the fast, safety and economical monitoring of the atherosclerotic disease progression and regression during therapy.

Spectral domain optical coherence tomography findings in tamoxifen retinopathy--a case report.

PubMed

Nair, Sandhya Narayanan; Anantharaman, Giridhar; Gopalakrishnan, Mahesh; Vyas, Jyothiprakash

2013-01-01

To report spectral domain optical coherence tomography findings in a case of typical tamoxifen retinopathy. In this observational case report, a patient with tamoxifen retinopathy was imaged with spectral domain optical coherence tomography and fundus auto fluorescence. Spectral domain optical coherence tomography showed numerous hyperreflective spots within the retina, mainly in the inner retinal layers in both the eyes. The external limiting membrane, the Inner Segment-Outer Segment junction, and the photoreceptors were not discernable at the fovea in the right eye. In the left eye, there was foveal atrophy with total loss of photoreceptors. The autofluorescent images showed macular hypofluorescence with foveal hyperfluorescence. Spectral domain optical coherence tomography demonstrated abnormalities in the outer retinal layers in tamoxifen retinopathy. There were also characteristic alterations in the autofluorescence pattern at the macula in tamoxifen retinopathy.

Stimulus-evoked outer segment changes in rod photoreceptors

NASA Astrophysics Data System (ADS)

Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Lu, Yiming; Gai, Shaoyan; Yao, Xincheng

2016-06-01

Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation.

Comparative investigation of stimulus-evoked rod outer segment movement and retinal electrophysiological activity

NASA Astrophysics Data System (ADS)

Lu, Yiming; Wang, Benquan; Yao, Xincheng

2017-02-01

Transient retinal phototropism (TRP) has been observed in rod photoreceptors activated by oblique visible light flashes. Time-lapse confocal microscopy and optical coherence tomography (OCT) revealed rod outer segment (ROS) movements as the physical source of TRP. However, the physiological source of TRP is still not well understood. In this study, concurrent TRP and electroretinogram (ERG) measurements disclosed a remarkably earlier onset time of the ROS movements (<=10 ms) than that ( 38 ms) of the ERG a-wave. Furthermore, low sodium treatment reversibly blocked the photoreceptor ERG a-wave, which is known to reflect hyperpolarization of retinal photoreceptors, but preserved the TRP associated rod OS movements well. Our experimental results and theoretical analysis suggested that the physiological source of TRP might be attributed to early stages of phototransduction, before the hyperpolarization of retinal photoreceptors.

Stimulus-evoked outer segment changes in rod photoreceptors

PubMed Central

Zhao, Xiaohui; Thapa, Damber; Wang, Benquan; Lu, Yiming; Gai, Shaoyan; Yao, Xincheng

2016-01-01

Abstract. Rod-dominated transient retinal phototropism (TRP) has been recently observed in freshly isolated mouse and frog retinas. Comparative confocal microscopy and optical coherence tomography revealed that the TRP was predominantly elicited from the rod outer segment (OS). However, the biophysical mechanism of rod OS dynamics is still unknown. Mouse and frog retinal slices, which displayed a cross-section of retinal photoreceptors and other functional layers, were used to test the effect of light stimulation on rod OSs. Time-lapse microscopy revealed stimulus-evoked conformational changes of rod OSs. In the center of the stimulated region, the length of the rod OS shrunk, while in the peripheral region, the rod OS swung toward the center region. Our experimental observation and theoretical analysis suggest that the TRP may reflect unbalanced rod disc-shape changes due to localized visible light stimulation. PMID:27334933

Evidence of early ultrastructural photoreceptor abnormalities in light-induced retinal degeneration using spectral domain optical coherence tomography.

PubMed

Aziz, Mehak K; Ni, Aiguo; Esserman, Denise A; Chavala, Sai H

2014-07-01

To study spatiotemporal in vivo changes in retinal morphology and quantify thickness of retinal layers in a mouse model of light-induced retinal degeneration using spectral domain optical coherence tomography (SD-OCT). BALB/c mice were exposed to 5000 lux of constant light for 3 h. SD-OCT images were taken 3 h, 24 h, 3 days, 1 week and 1 month after light exposure and were compared with histology at the same time points. SD-OCT images were also taken at 0, 1 and 2 h after light exposure in order to analyse retinal changes at the earliest time points. The thickness of retinal layers was measured using the Bioptigen software InVivoVue Diver. SD-OCT demonstrated progressive outer retinal thinning. 3 h after light exposure, the outer nuclear layer converted from hyporeflective to hyper-reflective. At 24 h, outer retinal bands and nuclear layer demonstrated similar levels of hyper-reflectivity. Significant variations in outer retinal thickness, vitreous opacities and retinal detachments occurred within days of injury. Thinning of the retina was observed at 1 month after injury. It was also determined that outer nuclear layer changes precede photoreceptor segment structure disintegration and the greatest change in segment structure occurs between 1 and 2 h after light exposure. Longitudinal SD-OCT reveals intraretinal changes that cannot be observed by histopathology at early time points in the light injury model. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

High-gradient compact linear accelerator

DOEpatents

Carder, B.M.

1998-05-26

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter. 10 figs.

High-gradient compact linear accelerator

DOEpatents

Carder, Bruce M.

1998-01-01

A high-gradient linear accelerator comprises a solid-state stack in a vacuum of five sets of disc-shaped Blumlein modules each having a center hole through which particles are sequentially accelerated. Each Blumlein module is a sandwich of two outer conductive plates that bracket an inner conductive plate positioned between two dielectric plates with different thicknesses and dielectric constants. A third dielectric core in the shape of a hollow cylinder forms a casing down the series of center holes, and it has a dielectric constant different that the two dielectric plates that sandwich the inner conductive plate. In operation, all the inner conductive plates are charged to the same DC potential relative to the outer conductive plates. Next, all the inner conductive plates are simultaneously shorted to the outer conductive plates at the outer diameters. The signal short will propagate to the inner diameters at two different rates in each Blumlein module. A faster wave propagates quicker to the third dielectric core across the dielectric plates with the closer spacing and lower dielectric constant. When the faster wave reaches the inner extents of the outer and inner conductive plates, it reflects back outward and reverses the field in that segment of the dielectric core. All the field segments in the dielectric core are then in unipolar agreement until the slower wave finally propagates to the third dielectric core across the dielectric plates with the wider spacing and higher dielectric constant. During such unipolar agreement, particles in the core are accelerated with gradients that exceed twenty megavolts per meter.

Barrier properties of cultured retinal pigment epithelium.

PubMed

Rizzolo, Lawrence J

2014-09-01

The principal function of an epithelium is to form a dynamic barrier that regulates movement between body compartments. Each epithelium is specialized with barrier functions that are specific for the tissues it serves. The apical surface commonly faces a lumen, but the retinal pigment epithelium (RPE) appears to be unique by a facing solid tissue, the sensory retina. Nonetheless, there exists a thin (subretinal) space that can become fluid filled during pathology. RPE separates the subretinal space from the blood supply of the outer retina, thereby forming the outer blood-retinal barrier. The intricate interaction between the RPE and sensory retina presents challenges for learning how accurately culture models reflect native behavior. The challenge is heightened by findings that detail the variation of RPE barrier proteins both among species and at different stages of the life cycle. Among the striking differences is the expression of claudin family members. Claudins are the tight junction proteins that regulate ion diffusion across the spaces that lie between the cells of a monolayer. Claudin expression by RPE varies with species and life-stage, which implies functional differences among commonly used animal models. Investigators have turned to transcriptomics to supplement functional studies when comparing native and cultured tissue. The most detailed studies of the outer blood-retinal barrier have focused on human RPE with transcriptome and functional studies reported for human fetal, adult, and stem-cell derived RPE. Copyright © 2014 Elsevier Ltd. All rights reserved.

Side wall cooling for nozzle segments for a gas turbine

DOEpatents

Burdgick, Steven Sebastian

2002-01-01

A nozzle vane segment includes outer and inner band portions with a vane extending therebetween and defining first and second cavities separated by an impingement plate for flowing cooling medium for impingement cooling of nozzle side walls. The side wall of each nozzle segment has an undercut region. The impingement plate has an inturned flange with a plurality of openings. Cooling inserts or receptacles having an open end are received in the openings and the base and side walls of the receptacles have apertures for receiving cooling medium from the first cavity and directing the cooling medium for impingement cooling of the side wall of the nozzle segment and a portion of the nozzle wall.

A new species of Condyloderes (Cyclorhagida, Kinorhyncha) from Korea.

PubMed

Sørensen, Martin V; Rho, Hyun Soo; Kim, Dongsung

2010-03-01

A new kinorhynch species, Condyloderes megastigma sp. nov., is described from the Korea Strait. The new species is characterized by the presence of 16 placids with either eight, four, or two knobby projections, middorsal and lateroventral acicular spines on segments 1 to 9, lateroventral cuspidate spines on segment 2 in females only, but otherwise lateroventral cuspidate spines on segments 4 and 5, and 8 and 9 in both sexes. Unique for the new species is furthermore the presence of paired ventromedial appendages on segments 7 and 8, giant ventromedial sensory spots on segment 9, and a terminal segment consisting of one tergal and one sternal plate. The mouth cone and introvert armature are described in detail for the first time for the genus Condyloderes Higgins, 1969. This study reveals similarities in several morphological characters between this genus and species of Campyloderes Zelinka, 1913.

Respiratory potential in sapwood of old versus young ponderosa pine trees in the Pacific Northwest.

PubMed

Pruyn, Michele L; Gartner, Barbara L; Harmon, Mark E

2002-02-01

Our primary objective was to present and test a new technique for in vitro estimation of respiration of cores taken from old trees to determine respiratory trends in sapwood. Our secondary objective was to quantify effects of tree age and stem position on respiratory potential (rate of CO2 production of woody tissue under standardized laboratory conditions). We extracted cores from one to four vertical positions in boles of +200-, +50- and +15-year-old Pinus ponderosa Dougl. ex Laws. trees. Cores were divided into five segments corresponding to radial depths of inner bark; outer, middle and inner sapwood; and heartwood. Data suggested that core segment CO2 production was an indicator of its respiratory activity, and that potential artifacts caused by wounding and extraction were minimal. On a dry mass basis, respiratory potential of inner bark was 3-15 times greater than that of sapwood at all heights for all ages (P < 0.0001). Within sapwood at all heights and in all ages of trees, outer sapwood had a 30-60% higher respiratory potential than middle or inner sapwood (P < 0.005). Heartwood had only 2-10% of the respiratory potential of outer sapwood. For all ages of trees, sapwood rings produced in the same calendar year released over 50% more CO2 at treetops than at bases (P < 0.0001). When scaled to the whole-tree level on a sapwood volume basis, sapwood of younger trees had higher respiratory potential than sapwood of older trees. In contrast, the trend was reversed when using the outer-bark surface area of stems as a basis for comparing respiratory potential. The differences observed in respiratory potential calculated on a core dry mass, sapwood volume, or outer-bark surface area basis clearly demonstrate that the resulting trends within and among trees are determined by the way in which the data are expressed. Although these data are based on core segments rather than in vivo measurements, we conclude that the relative differences are probably valid even if the absolute differences are not.

Milk Technological Properties as Affected by Including Artichoke By-Products Silages in the Diet of Dairy Goats

PubMed Central

Muelas, Raquel; Romero, Gema; Sayas-Barberá, Estrella; Navarro, Casilda; Díaz, José Ramón

2017-01-01

Traditional farming practices include the use of local agricultural by-products in the diet of ruminants. Artichoke harvesting and transformation yield high amounts of by-products that, if properly used, may reduce farming costs and the environmental impact of farming. The present study tests the inclusion of silages from artichoke by-products (plant and outer bracts) in the diet of dairy goats (0%, 12.5% and 25% inclusion) on the technological and sensory properties of milk during a five-month study. Milk composition, color, stability, coagulation and fermentation properties remained unaffected by diet changes. Panelists were not able to differentiate among yogurts obtained from those milks by discriminant triangular sensory tests. Silages of artichoke by-products can be included in isoproteic and isoenergetic diets for dairy goats, up to a 25% (feed dry matter), without negatively affecting milk technological and sensory properties whereas reducing feeding costs. PMID:29258226

Sensory quality of fresh French and Dutch market tomatoes: a preference mapping study with Italian consumers.

PubMed

Sinesio, Fiorella; Cammareri, Maria; Moneta, Elisabetta; Navez, Brigitte; Peparaio, Marina; Causse, Mathilde; Grandillo, Silvana

2010-01-01

Sensory properties are important elements to evaluate the qualities of vegetable products and are also determinant factors in purchasing decision. Here we report the Italian results of a preference mapping study conducted within a larger European project with the aim of describing the preferences of European consumers in regard to the diversity of traditional and modern tomato varieties, available on the market. This study has allowed the assessment of fruit quality at 3 levels: objective description of sensory properties, consumer preference tests, and physicochemical measurements. A set of 16 tomato cultivars, with different fruit sizes and shapes, was described and classified according to 18 sensory attributes including flavor, appearance, and texture characteristics. The same cultivars were evaluated by 179 consumers in a "preference mapping" experiment with the goal of identifying the preferred varieties and the reasons for the choice. The consumer data are referred to hedonic ratings (aspect liking and overall liking), familiarity for the analyzed cultivars, and individual features collected by a questionnaire. A hierarchical analysis of the clusters allowed to distinguish, within the sampled Italian consumers, 4 segments with different preferences which represented 19%, 25%, 41%, and 15% of the population, respectively. A partial least square regression model allowed the identification of the sensory attributes that best described consumer cluster preferences for tomato cultivars. Both texture and flavor descriptors were important drivers of consumer preferences, but the relevance (predictive value) of individual descriptors to model tomato liking was different for each consumer segment. Information on demographic and behavioral characteristics, usage habits, and factors relevant for purchasing were also provided on the 4 groups of consumers.

Hair bundles of cochlear outer hair cells are shaped to minimize their fluid-dynamic resistance.

PubMed

Ciganović, Nikola; Wolde-Kidan, Amanuel; Reichenbach, Tobias

2017-06-15

The mammalian sense of hearing relies on two types of sensory cells: inner hair cells transmit the auditory stimulus to the brain, while outer hair cells mechanically modulate the stimulus through active feedback. Stimulation of a hair cell is mediated by displacements of its mechanosensitive hair bundle which protrudes from the apical surface of the cell into a narrow fluid-filled space between reticular lamina and tectorial membrane. While hair bundles of inner hair cells are of linear shape, those of outer hair cells exhibit a distinctive V-shape. The biophysical rationale behind this morphology, however, remains unknown. Here we use analytical and computational methods to study the fluid flow across rows of differently shaped hair bundles. We find that rows of V-shaped hair bundles have a considerably reduced resistance to crossflow, and that the biologically observed shapes of hair bundles of outer hair cells are near-optimal in this regard. This observation accords with the function of outer hair cells and lends support to the recent hypothesis that inner hair cells are stimulated by a net flow, in addition to the well-established shear flow that arises from shearing between the reticular lamina and the tectorial membrane.

Debris-less method and apparatus for forming apertures in hollow metallic articles

DOEpatents

Jordan, C.L.; Chodelka, E.J.

1980-06-24

This invention is a method for forming an aperture in a wall of a hollow metallic article without introducing metallic debris therein. In a typical operation, an annular groove is formed in an exterior portion of the wall. The groove defines an annular wall segment, and the bottom of the groove is shaped to slope downwardly away from the segment to form a tapered annular web which connects the segment to the wall. Any suitable coupling is attached to the outer face of the segment, as by welding. Pull then is applied to the coupling to effect circumferential breakage of the web, thus forming a removable single-piece wall fragment consisting of the web and segment. The fragment and the coupling member attached thereto then are removed from the wall.

A link-segment model of upright human posture for analysis of head-trunk coordination

NASA Technical Reports Server (NTRS)

Nicholas, S. C.; Doxey-Gasway, D. D.; Paloski, W. H.

1998-01-01

Sensory-motor control of upright human posture may be organized in a top-down fashion such that certain head-trunk coordination strategies are employed to optimize visual and/or vestibular sensory inputs. Previous quantitative models of the biomechanics of human posture control have examined the simple case of ankle sway strategy, in which an inverted pendulum model is used, and the somewhat more complicated case of hip sway strategy, in which multisegment, articulated models are used. While these models can be used to quantify the gross dynamics of posture control, they are not sufficiently detailed to analyze head-trunk coordination strategies that may be crucial to understanding its underlying mechanisms. In this paper, we present a biomechanical model of upright human posture that extends an existing four mass, sagittal plane, link-segment model to a five mass model including an independent head link. The new model was developed to analyze segmental body movements during dynamic posturography experiments in order to study head-trunk coordination strategies and their influence on sensory inputs to balance control. It was designed specifically to analyze data collected on the EquiTest (NeuroCom International, Clackamas, OR) computerized dynamic posturography system, where the task of maintaining postural equilibrium may be challenged under conditions in which the visual surround, support surface, or both are in motion. The performance of the model was tested by comparing its estimated ground reaction forces to those measured directly by support surface force transducers. We conclude that this model will be a valuable analytical tool in the search for mechanisms of balance control.

Conjoint analysis on the purchase intent for traditional fermented soy product (natto) among Japanese housewives.

PubMed

Kimura, Atsushi; Kuwazawa, Shigetaka; Wada, Yuji; Kyutoku, Yasushi; Okamoto, Masako; Yamaguchi, Yui; Masuda, Tomohiro; Dan, Ippeita

2011-04-01

The effect of sensory and extrinsic attributes on consumer intentions to purchase the Japanese traditional fermented soybean product natto was evaluated using conjoint analysis. Six attributes with 2 levels each were chosen and manipulated: price (high compared with low), the country of origin of the soybeans (domestic compared with imported), stickiness (strong compared with moderate), smell (rich compared with moderate), attached seasonings (attached compared with no attached seasonings), and the environmental friendliness of the packaging (high compared with low). A fractional factorial design was applied and 8 hypothetical product labels were produced. A sample of 479 Japanese housewives ranked these product labels based on their purchase intentions. Overall purchase intention was affected by country of origin, attached seasonings, and price; those attributes accounted for 81.0%, while the sensory attributes of the product accounted for 19.0% of purchase intents. In order to estimate market segments for the natto products based on consumer preference, a cluster analysis was performed. It identified 4 segments of consumers: 1 oriented to attached seasonings, another conscious of the price, and the other 2 oriented to origins. The behavioral and demographic characteristics of the respondents had a limited influence on segment membership.   This research was conducted to understand how consumers valuate various sensory and nonsensory product attributes based on their assessment of the overall product in the case of Japanese fermented soy product (natto). The data of this research would be of great importance both in understanding consumer behavior and in designing strategies for product development.

Spinal anesthesia: a comparison of procaine and lidocaine.

PubMed

Le Truong, H H; Girard, M; Drolet, P; Grenier, Y; Boucher, C; Bergeron, L

2001-05-01

To compare spinal procaine to spinal lidocaine with regard to their main clinical characteristics and incidence of transient radicular irritation (TRI). In this randomized, double-blind, prospective study, patients (two groups, n=30 each) received either 100 mg of lidocaine 5% in 7.5% glucose (Group L) or 100 mg of procaine 10% diluted with 1 ml cerebrospinal fluid (Group P). After spinal anesthesia, segmental level of sensory block was assessed by pinprick. Blood pressure and the height of the block were noted each minute for the first ten minutes, then every three minutes for the next 35 min and finally every five minutes until regression of the block to L4. Motor blockade was evaluated using the Bromage scale. To evaluate the presence of TRI, each patient was questioned 48 hr after surgery. Time to highest sensory level and to maximum number of segments blocked showed no difference between groups. Mean time for sensory regression to T10 and for regression of the motor block were shorter in Group P. Eighty minutes following injection, sensory levels were lower in Group P. Five patients had inadequate surgical anesthesia in Group P and only one in Group L. No patient in Group P had TRI (95% CI 10-12%) while eight (27%) in Group L did (95% CI 12-46%). Procaine 10% was associated with a clinical failure rate of 14.2%. This characteristic must be balanced against an absence of TRI, which occurs more frequently with the use of lidocaine 5%.

Denoising and segmentation of retinal layers in optical coherence tomography images

NASA Astrophysics Data System (ADS)

Dash, Puspita; Sigappi, A. N.

2018-04-01

Optical Coherence Tomography (OCT) is an imaging technique used to localize the intra-retinal boundaries for the diagnostics of macular diseases. Due to speckle noise, low image contrast and accurate segmentation of individual retinal layers is difficult. Due to this, a method for retinal layer segmentation from OCT images is presented. This paper proposes a pre-processing filtering approach for denoising and segmentation methods for segmenting retinal layers OCT images using graph based segmentation technique. These techniques are used for segmentation of retinal layers for normal as well as patients with Diabetic Macular Edema. The algorithm based on gradient information and shortest path search is applied to optimize the edge selection. In this paper the four main layers of the retina are segmented namely Internal limiting membrane (ILM), Retinal pigment epithelium (RPE), Inner nuclear layer (INL) and Outer nuclear layer (ONL). The proposed method is applied on a database of OCT images of both ten normal and twenty DME affected patients and the results are found to be promising.

Motor contributions to the temporal precision of auditory attention

PubMed Central

Morillon, Benjamin; Schroeder, Charles E.; Wyart, Valentin

2014-01-01

In temporal—or dynamic—attending theory, it is proposed that motor activity helps to synchronize temporal fluctuations of attention with the timing of events in a task-relevant stream, thus facilitating sensory selection. Here we develop a mechanistic behavioural account for this theory by asking human participants to track a slow reference beat, by noiseless finger pressing, while extracting auditory target tones delivered on-beat and interleaved with distractors. We find that overt rhythmic motor activity improves the segmentation of auditory information by enhancing sensitivity to target tones while actively suppressing distractor tones. This effect is triggered by cyclic fluctuations in sensory gain locked to individual motor acts, scales parametrically with the temporal predictability of sensory events and depends on the temporal alignment between motor and attention fluctuations. Together, these findings reveal how top-down influences associated with a rhythmic motor routine sharpen sensory representations, enacting auditory ‘active sensing’. PMID:25314898

Motor contributions to the temporal precision of auditory attention.

PubMed

Morillon, Benjamin; Schroeder, Charles E; Wyart, Valentin

2014-10-15

In temporal-or dynamic-attending theory, it is proposed that motor activity helps to synchronize temporal fluctuations of attention with the timing of events in a task-relevant stream, thus facilitating sensory selection. Here we develop a mechanistic behavioural account for this theory by asking human participants to track a slow reference beat, by noiseless finger pressing, while extracting auditory target tones delivered on-beat and interleaved with distractors. We find that overt rhythmic motor activity improves the segmentation of auditory information by enhancing sensitivity to target tones while actively suppressing distractor tones. This effect is triggered by cyclic fluctuations in sensory gain locked to individual motor acts, scales parametrically with the temporal predictability of sensory events and depends on the temporal alignment between motor and attention fluctuations. Together, these findings reveal how top-down influences associated with a rhythmic motor routine sharpen sensory representations, enacting auditory 'active sensing'.

Sensory factors affecting female consumers' acceptability of nail polish.

PubMed

Sun, C; Koppel, K; Adhikari, K

2015-12-01

The objectives of this study were to determine what sensory factors impact consumers' acceptability of nail polishes, to explore how these sensory factors impact consumers' acceptability of nail polishes, to investigate whether there are any consumer segments according to their overall acceptability on different nail polishes and to scrutinize how the consumer segments are related to the sensory factors. Ninety-eight females participated in a nail polish consumer study at Kansas State University. Eight commercial products belonging to four categories - regular (REG), gel (GEL), flake (FLK) and water-based (WAT) - were evaluated. Each nail polish sample was evaluated twice by each participant in two different tasks - a task devoted to applying and evaluating the product and a task devoted to observing the appearance and evaluating the product. Pearson's correlation analysis, analysis of variance (ANOVA), external preference mapping, cluster analysis and internal preference mapping were applied for data analysis. Participants' scores of overall liking of the nail polishes were similar in the application task and in the observation task. In general, participants liked the REG and GEL product samples more than the FLK and WAT samples. Among all the sensory attributes, appearance attributes were the major factors that affected participants' overall liking. Aroma seemed to be a minor factor to participants' overall liking. Some sensory attributes, such as runny, shininess, opacity, spreadability, smoothness, coverage and wet appearance, were found to drive participants' overall acceptability positively, whereas others such as pinhole, fatty-edges, blister, brushlines, pearl-like, flake-protrusion, glittery and initial-drag impacted participants' overall acceptability negatively. Four clusters of participants were identified according to their overall liking scores from both the application task and the observation task. Participants' acceptability, based on different sensory attributes, could help a nail polish manufacturer modify or improve their nail polish formulas. Nail polish manufacturers could use the consumer cluster information to improve their marketing strategies for specific categories of their products and to target their advertising on particular consumer groups. © 2015 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Use of optical coherence tomography to evaluate visual acuity and visual field changes in dengue fever.

PubMed

Rhee, Taek Kwan; Han, Jung Il

2014-02-01

Dengue fever is a viral disease that is transmitted by mosquitoes and affects humans. In rare cases, dengue fever can cause visual impairment, which usually occurs within 1 month after contracting dengue fever and ranges from mild blurring of vision to severe blindness. Visual impairment due to dengue fever can be detected through angiography, retinography, optical coherence tomography (OCT) imaging, electroretinography, event electroencephalography (visually evoked potentials), and visual field analysis. The purpose of this study is to report changes in the eye captured using fluorescein angiography, indocyanine green, and OCT in 3 cases of dengue fever visual impairment associated with consistent visual symptoms and similar retinochoroidopathic changes. The OCT results of the three patients with dengue fever showed thinning of the outer retinal layer and disruption of the inner segment/outer segment (IS/OS) junction. While thinning of the retina outer layer is an irreversible process, disruption of IS/OS junction is reported to be reversible. Follow-up examination of individuals with dengue fever and associated visual impairment should involve the use of OCT to evaluate visual acuity and visual field changes in patients with acute choroidal ischemia.

Recapitulating X-Linked Juvenile Retinoschisis in Mouse Model by Knock-In Patient-Specific Novel Mutation.

PubMed

Chen, Ding; Xu, Tao; Tu, Mengjun; Xu, Jinlin; Zhou, Chenchen; Cheng, Lulu; Yang, Ruqing; Yang, Tanchu; Zheng, Weiwei; He, Xiubin; Deng, Ruzhi; Ge, Xianglian; Li, Jin; Song, Zongming; Zhao, Junzhao; Gu, Feng

2017-01-01

X-linked juvenile retinoschisis (XLRS) is a retinal disease caused by mutations in the gene encoding retinoschisin (RS1), which leads to a significant proportion of visual impairment and blindness. To develop personalized genome editing based gene therapy, knock-in animal disease models that have the exact mutation identified in the patients is extremely crucial, and that the way which genome editing in knock-in animals could be easily transferred to the patients. Here we recruited a family diagnosed with XLRS and identified the causative mutation ( RS1 , p.Y65X), then a knock-in mouse model harboring this disease-causative mutation was generated via TALEN (transcription activator-like effector nucleases). We found that the b-wave amplitude of the ERG of the RS1 -KI mice was significantly decreased. Moreover, we observed that the structure of retina in RS1 -KI mice has become disordered, including the disarray of inner nuclear layer and outer nuclear layer, chaos of outer plexiform layer, decreased inner segments of photoreceptor and the loss of outer segments. The novel knock-in mice ( RS1 -KI) harboring patient-specific mutation will be valuable for development of treatment via genome editing mediated gene correction.

Ceramic turbine nozzle

DOEpatents

Shaffer, James E.; Norton, Paul F.

1996-01-01

A turbine nozzle and shroud assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes a plurality of segmented vane defining a first vane segment and a second vane segment. Each of the first and second vane segments having a vertical portion. Each of the first vane segments and the second vane segments being positioned in functional relationship one to another within a recess formed within an outer shroud and an inner shroud. The turbine nozzle and shroud assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the other component.

Ceramic turbine nozzle

DOEpatents

Shaffer, J.E.; Norton, P.F.

1996-12-17

A turbine nozzle and shroud assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components have a preestablished rate of thermal expansion greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes a plurality of segmented vane defining a first vane segment and a second vane segment, each of the first and second vane segments having a vertical portion, and each of the first vane segments and the second vane segments being positioned in functional relationship one to another within a recess formed within an outer shroud and an inner shroud. The turbine nozzle and shroud assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being less than the preestablished rate of thermal expansion of the other component. 4 figs.

Spine Patterning Is Guided by Segmentation of the Notochord Sheath.

PubMed

Wopat, Susan; Bagwell, Jennifer; Sumigray, Kaelyn D; Dickson, Amy L; Huitema, Leonie F A; Poss, Kenneth D; Schulte-Merker, Stefan; Bagnat, Michel

2018-02-20

The spine is a segmented axial structure made of alternating vertebral bodies (centra) and intervertebral discs (IVDs) assembled around the notochord. Here, we show that, prior to centra formation, the outer epithelial cell layer of the zebrafish notochord, the sheath, segments into alternating domains corresponding to the prospective centra and IVD areas. This process occurs sequentially in an anteroposterior direction via the activation of Notch signaling in alternating segments of the sheath, which transition from cartilaginous to mineralizing domains. Subsequently, osteoblasts are recruited to the mineralized domains of the notochord sheath to form mature centra. Tissue-specific manipulation of Notch signaling in sheath cells produces notochord segmentation defects that are mirrored in the spine. Together, our findings demonstrate that notochord sheath segmentation provides a template for vertebral patterning in the zebrafish spine. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

Differential approach to strategies of segmental stabilisation in postural control.

PubMed

Isableu, Brice; Ohlmann, Théophile; Crémieux, Jacques; Amblard, Bernard

2003-05-01

The present paper attempts to clarify the between-subjects variability exhibited in both segmental stabilisation strategies and their subordinated or associated sensory contribution. Previous data have emphasised close relationships between the interindividual variability in both the visual control of posture and the spatial visual perception. In this study, we focused on the possible relationships that might link perceptual visual field dependence-independence and the visual contribution to segmental stabilisation strategies. Visual field dependent (FD) and field independent (FI) subjects were selected on the basis of their extreme score in a static rod and frame test where an estimation of the subjective vertical was required. In the postural test, the subjects stood in the sharpened Romberg position in darkness or under normal or stroboscopic illumination, in front of either a vertical or a tilted frame. Strategies of segmental stabilisation of the head, shoulders and hip in the roll plane were analysed by means of their anchoring index (AI). Our hypothesis was that FD subjects might use mainly visual cues for calibrating not only their spatial perception but also their strategies of segmental stabilisation. In the case of visual cue disturbances, a greater visual dependency to the strategies of segmental stabilisation in FD subjects should be validated by observing more systematic "en bloc" functioning (i.e. negative AI) between two adjacent segments. The main results are the following: 1. Strategies of segmental stabilisation differed between both groups and differences were amplified with the deprivation of either total vision and/or static visual cues. 2. In the absence of total vision and/or static visual cues, FD subjects have shown an increased efficiency of the hip stabilisation in space strategy and an "en bloc" operation of the shoulder-hip unit (whole trunk). The last "en bloc" operation was extended to the whole head-trunk unit in darkness, associated with a hip stabilisation in space. 3. The FI subjects have adopted neither a strategy of segmental stabilisation in space nor on the underlying segment, whatever the body segment considered and the visual condition. Thus, in this group, head, shoulder and hip moved independently from each other during stance control, roughly without taking into account the visual condition. The results, emphasising a differential weighting of sensory input involved in both perceptual and postural control, are discussed in terms of the differential choice and/or ability to select the adequate frame of reference common to both cognitive and motor spatial activities. We assumed that a motor-somesthetics "neglect" or a lack of mastering of these inputs/outputs rather than a mere visual dependence in FD subjects would generate these interindividual differences in both spatial perception and postural balance. This proprioceptive "neglect" is assumed to lead FD subjects to sensory reweighting, whereas proprioceptive dominance would lead FI subjects to a greater ability in selecting the adequate frame of reference in the case of intersensory disturbances. Finally, this study also provides evidence for a new interpretation of the visual field dependence-independence dimension in both spatial perception and postural control.

Thyroid hormone increases fibroblast growth factor receptor expression and disrupts cell mechanics in the developing organ of corti

PubMed Central

2013-01-01

Background Thyroid hormones regulate growth and development. However, the molecular mechanisms by which thyroid hormone regulates cell structural development are not fully understood. The mammalian cochlea is an intriguing system to examine these mechanisms, as cellular structure plays a key role in tissue development, and thyroid hormone is required for the maturation of the cochlea in the first postnatal week. Results In hypothyroid conditions, we found disruptions in sensory outer hair cell morphology and fewer microtubules in non-sensory supporting pillar cells. To test the functional consequences of these cytoskeletal defects on cell mechanics, we combined atomic force microscopy with live cell imaging. Hypothyroidism stiffened outer hair cells and supporting pillar cells, but pillar cells ultimately showed reduced cell stiffness, in part from a lack of microtubules. Analyses of changes in transcription and protein phosphorylation suggest that hypothyroidism prolonged expression of fibroblast growth factor receptors, and decreased phosphorylated Cofilin. Conclusions These findings demonstrate that thyroid hormones may be involved in coordinating the processes that regulate cytoskeletal dynamics and suggest that manipulating thyroid hormone sensitivity might provide insight into the relationship between cytoskeletal formation and developing cell mechanical properties. PMID:23394545

Foveal damage in habitual poppers users.

PubMed

Audo, Isabelle; El Sanharawi, Mohamed; Vignal-Clermont, Catherine; Villa, Antoine; Morin, Annie; Conrath, John; Fompeydie, Dominique; Sahel, José-Alain; Gocho-Nakashima, Kiyoko; Goureau, Olivier; Paques, Michel

2011-06-01

To describe foveal damage in habitual use of poppers, a popular recreational drug. Retrospective observational case series. Six patients with bilateral vision loss after chronic popper inhalation were seen in 4 university-based ophthalmology departments. Symptoms, medical history, ophthalmic examination, and functional and morphological tests are described. All patients experienced progressive bilateral vision loss, with central photopsia in 2 cases. Initial visual acuities ranged from 20/50 to 20/25. In all patients, a bilateral yellow foveal spot was present that, by optical coherence tomography, was associated with disruption of the outer segments of foveal cones. Functional and anatomical damage was restricted to the fovea. The poppers involved were identified as isopropyl nitrite in 3 cases. Four patients showed anatomical and/or functional improvement over several months after discontinuing popper inhalation. Repeated inhalation of poppers may be associated with prolonged bilateral vision loss due to the disruption of foveal cone outer segments. Retinal damage may progressively improve following drug discontinuation.

Method of controlling the side wall thickness of a turbine nozzle segment for improved cooling

DOEpatents

Burdgick, Steven Sebastian

2002-01-01

A gas turbine nozzle segment has outer and inner bands and a vane extending therebetween. Each band has a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band has an inturned flange defining with the nozzle wall an undercut region. The outer surface of the side wall is provided with a step prior to welding the cover to the side wall. A thermal barrier coating is applied in the step and, after the cover is welded to the side wall, the side wall is finally machined to a controlled thickness removing all, some or none of the coating.

The proline-rich domain of TonB possesses an extended polyproline II-like conformation of sufficient length to span the periplasm of Gram-negative bacteria

PubMed Central

Köhler, Silvia Domingo; Weber, Annemarie; Howard, S Peter; Welte, Wolfram; Drescher, Malte

2010-01-01

TonB from Escherichia coli and its homologues are critical for the uptake of siderophores through the outer membrane of Gram-negative bacteria using chemiosmotic energy. When different models for the mechanism of TonB mediated energy transfer from the inner to the outer membrane are discussed, one of the key questions is whether TonB spans the periplasm. In this article, we use long range distance measurements by spin-label pulsed EPR (Double Electron–Electron Resonance, DEER) and CD spectroscopy to show that the proline-rich segment of TonB exists in a PPII-like conformation. The result implies that the proline-rich segment of TonB possesses a length of more than 15 nm, sufficient to span the periplasm of Gram-negative bacteria. PMID:20095050

KSC-08pd3565

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, these Ares I-X upper stage simulator segments have shed their protective blue shrink-wrapped covers used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

KSC-08pd3564

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, these Ares I-X upper stage simulator segments have shed their protective blue shrink-wrapped covers used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

KSC-08pd3570

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, these Ares I-X upper stage simulator segments have shed their protective blue shrink-wrapped covers used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

Spectral domain optical coherence tomography findings in acute syphilitic posterior placoid chorioretinitis.

PubMed

Burkholder, Bryn M; Leung, Theresa G; Ostheimer, Trucian A; Butler, Nicholas J; Thorne, Jennifer E; Dunn, James P

2014-01-27

We describe the spectral domain optical coherence tomography (SD-OCT) findings in three patients with acute syphilitic posterior placoid chorioretinitis (ASPPC). The SD-OCT images demonstrate the pathologic changes in ASPPC with a high level of anatomic detail and may provide information about the pathophysiology of the disease. We report a series of three consecutive patients seen at the Wilmer Eye Institute in 2012 and 2013 who presented with clinical and laboratory findings consistent with a diagnosis of unilateral ASPPC. Two of the three patients had HIV co-infection with good immune recovery. SD-OCT images from their initial (pre-treatment) presentation demonstrated thickening and hyperreflective nodularity of the choroid-retinal pigment epithelium (RPE) complex, with focal disruption of the overlying photoreceptor inner segment-outer segment junction in the areas corresponding to the retinal lesions seen on clinical examination. These changes improved with intravenous antibiotic treatment over a 3-month period of follow-up. SD-OCT imaging in ASPPC demonstrates reversible, focal thickening, and nodularity of the RPE with disruption of the overlying photoreceptor inner segment-outer segment junction. We believe that these SD-OCT images support the concept that ASPPC involves an inflammatory process at the level of the choroid-RPE with resultant structural and functional changes in the retinal photoreceptors. Further study with OCT imaging may be helpful in better understanding this disease.

Diabetic retinal pigment epitheliopathy: fundus autofluorescence and spectral-domain optical coherence tomography findings.

PubMed

Kang, Eui Chun; Seo, Yuri; Byeon, Suk Ho

2016-10-01

To describe the characteristics of an unfamiliar disease entity, diabetic retinal pigment epitheliopathy (DRPE), using fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT). This retrospective study included 17 eyes from 10 proliferative diabetic retinopathy (PDR) patients with granular hypo-autofluorescence and/or variable hyper-autofluorescence on FAF (DRPE group) and 17 eyes from 10 age- and sex-matched PDR patients without abnormal autofluorescence (PDR group). Eyes with diabetic macular edema were excluded. Visual acuity (VA), retinal thickness (RT), and choroidal thickness (CT) were compared between the groups. Eyes in the DRPE group had worse logMAR VA than eyes in the PDR group (0.369 ± 0.266 vs. 0.185 ± 0.119; P = 0.026). The thickness of the retinal pigment epithelium plus the inner segment/outer segment of the photoreceptors was reduced to a greater degree in the DRPE group than the PDR group (P < 0.001). Moreover, the thickness of the outer nuclear layer plus the outer plexiform layer was thinner in the DRPE group than in the PDR (P = 0.013). However, the thickness of the inner retina showed no differences between the two groups. CT was significantly thicker in the DRPE group than in the PDR group (329.00 ± 33.76 vs. 225.62 ± 37.47 μm; P < 0.001). Eyes with DRPE showed reduced VA, a thinner outer retina, and thicker choroid in comparison with eyes with PDR. Alterations of autofluorescence on FAF and changes in the outer retinal thickness and CT on SD-OCT can be helpful for differentiating DRPE in patients with PDR.

Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo.

PubMed

Berkowitz, Bruce A; Gorgis, Jawan; Patel, Ankit; Baameur, Faiza; Gurevich, Vsevolod V; Craft, Cheryl M; Kefalov, Vladimir J; Roberts, Robin

2015-02-01

Rod tetrameric arrestin 1 (tet-ARR1), stored in the outer nuclear layer/inner segments in the dark, modulates photoreceptor synaptic activity; light exposure stimulates a reduction via translocation to the outer segments for terminating G-protein coupled phototransduction signaling. Here, we test the hypothesis that intraretinal spin-lattice relaxation rate in the rotating frame (1/T1ρ), an endogenous MRI contrast mechanism, has high potential for evaluating rod tet-ARR1 and its reduction via translocation. Dark- and light-exposed mice (null for the ARR1 gene, overexpressing ARR1, diabetic, or wild type with or without treatment with Mn2+, a calcium channel probe) were studied using 1/T1ρ MRI. Immunohistochemistry and single-cell recordings of the retinas were also performed. In wild-type mice with or without treatment with Mn2+, 1/T1ρ of avascular outer retina (64% to 72% depth) was significantly (P < 0.05) greater in the dark than in the light; a significant (P < 0.05) but opposite pattern was noted in the inner retina (<50% depth). Light-evoked outer retina Δ1/T1ρ was absent in ARR1-null mice and supernormal in overexpressing mice. In diabetic mice, the outer retinal Δ1/T1ρ pattern suggested normal dark-to-light tet-ARR1 translocation and chromophore content, conclusions confirmed ex vivo. Light-stimulated Δ1/T1ρ in inner retina was linked to changes in blood volume. Our data support 1/T1ρ MRI for noninvasively assessing rod tet-ARR1 and its reduction via protein translocation, which can be combined with other metrics of retinal function in vivo. © FASEB.

KSC-08pd3571

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, Ares I-X upper stage simulator segments are lined up. Their protective blue shrink-wrapped covers used for shipping are being removed, as seen on the segments at left and in the back. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

Photoreceptor Outer Segment on Internal Limiting Membrane after Macular Hole Surgery: Implications for Pathogenesis.

PubMed

Grinton, Michael E; Sandinha, Maria T; Steel, David H W

2015-01-01

This report presents a case, which highlights key principles in the pathophysiology of macular holes. It has been hypothesized that anteroposterior (AP) and tangential vitreous traction on the fovea are the primary underlying factors causing macular holes [Nischal and Pearson; in Kanski and Bowling: Clinical Ophthalmology: A Systemic Approach, 2011, pp 629-631]. Spectral domain optical coherence tomography (OCT) has subsequently corroborated this theory in part but shown that AP vitreofoveal traction is the more common scenario [Steel and Lotery: Eye 2013;27:1-21]. This study was conducted as a single case report. A 63-year old female presented to her optician with blurred and distorted vision in her left eye. OCT showed a macular hole with a minimum linear diameter of 370 µm, with persistent broad vitreofoveal attachment on both sides of the hole edges. The patient underwent combined left phacoemulsification and pars plana vitrectomy, internal limiting membrane (ILM) peel and gas injection. The ILM was examined by electron microscopy and showed the presence of a cone outer segment on the retinal side. Post-operative OCT at 11 weeks showed a closed hole with recovery of the foveal contour and good vision. Our case shows the presence of a photoreceptor outer segment on the retinal side of the ILM and reinforces the importance of tangential traction in the development of some macula holes. The case highlights the theory of transmission of inner retinal forces to the photoreceptors via Müller cells and how a full thickness macular hole defect can occur in the absence of AP vitreomacular traction.

Rod Photopigment Kinetics After Photodisruption of the Retinal Pigment Epithelium

PubMed Central

Masella, Benjamin D.; Hunter, Jennifer J.; Williams, David R.

2014-01-01

Purpose. Advances in retinal imaging have led to the discovery of long-lasting retinal changes caused by light exposures below published safety limits, including disruption of the RPE. To investigate the functional consequences of RPE disruption, we combined adaptive optics ophthalmoscopy with retinal densitometry. Methods. A modified adaptive optics scanning light ophthalmoscope (AOSLO) measured the apparent density and regeneration rate of rhodopsin in two macaques before and after four different 568-nm retinal radiant exposures (RREs; 400–3200 J/cm2). Optical coherence tomography (OCT) was used to measure the optical path length through the photoreceptor outer segments before and after RPE disruption. Results. All tested RREs caused visible RPE disruption. Apparent rhodopsin density was significantly reduced following 1600 (P = 0.01) and 3200 J/cm2 (P = 0.007) exposures. No significant change in apparent density was observed in response to 800 J/cm2. Surprisingly, exposure to 400 J/cm2 showed a significant increase in apparent density (P = 0.047). Rhodopsin recovery rate was not significantly affected by these RREs. Optical coherence tomography measurements showed a significant decrease in the optical path length through the photoreceptor outer segments for RREs above 800 J/cm2 (P < 0.001). Conclusions. At higher RREs, optical path length through the outer segments was reduced. However, the rate of photopigment regeneration was unchanged. While some ambiguity remains as to the correlation between measured reflectivity and absolute rhodopsin density; at the lowest RREs, RPE disruption appears not to be accompanied by a loss of apparent rhodopsin density, which would have been indicative of functional loss. PMID:25316724

Enhanced Visualization of Subtle Outer Retinal Pathology by En Face Optical Coherence Tomography and Correlation with Multi-Modal Imaging

PubMed Central

Chew, Avenell L.; Lamey, Tina; McLaren, Terri; De Roach, John

2016-01-01

Purpose To present en face optical coherence tomography (OCT) images generated by graph-search theory algorithm-based custom software and examine correlation with other imaging modalities. Methods En face OCT images derived from high density OCT volumetric scans of 3 healthy subjects and 4 patients using a custom algorithm (graph-search theory) and commercial software (Heidelberg Eye Explorer software (Heidelberg Engineering)) were compared and correlated with near infrared reflectance, fundus autofluorescence, adaptive optics flood-illumination ophthalmoscopy (AO-FIO) and microperimetry. Results Commercial software was unable to generate accurate en face OCT images in eyes with retinal pigment epithelium (RPE) pathology due to segmentation error at the level of Bruch’s membrane (BM). Accurate segmentation of the basal RPE and BM was achieved using custom software. The en face OCT images from eyes with isolated interdigitation or ellipsoid zone pathology were of similar quality between custom software and Heidelberg Eye Explorer software in the absence of any other significant outer retinal pathology. En face OCT images demonstrated angioid streaks, lesions of acute macular neuroretinopathy, hydroxychloroquine toxicity and Bietti crystalline deposits that correlated with other imaging modalities. Conclusions Graph-search theory algorithm helps to overcome the limitations of outer retinal segmentation inaccuracies in commercial software. En face OCT images can provide detailed topography of the reflectivity within a specific layer of the retina which correlates with other forms of fundus imaging. Our results highlight the need for standardization of image reflectivity to facilitate quantification of en face OCT images and longitudinal analysis. PMID:27959968

Ultra-Wide-Field Fundus Autofluorescence and Spectral-Domain Optical Coherence Tomography Findings in Syphilitic Outer Retinitis.

PubMed

Saleh, Mohamed G A; Campbell, John Peter; Yang, Paul; Lin, Phoebe

2017-03-01

To determine the ultra-wide-field fundus autofluorescence (UWFFAF) and optical coherence tomography (OCT) features of syphilitic outer retinopathy (SOR). Retrospective chart review. Three patients with SOR were investigated. Treatment with parenteral penicillin led to improvement of outer retinopathy, visual acuity, and symptoms. UWFFAF showed speckled hyperautofluorescence, hypoautofluorescence, and normal autofluorescence, similar to what has been described as a trizonal pattern in acute zonal occult outer retinopathy (AZOOR) in the chronic case of SOR, but with hyperautofluorescent areas in the two acute cases. OCT showed disruption of the photoreceptor outer segment ellipsoid zone and external limiting membrane, which improved after penicillin treatment, and corresponded to normalization of the hyperautofluorescent areas on UWFFAF. There was irregularity and nodular thickening of retinal pigment epithelium on OCT in areas of mottled hyperautofluorescence. SOR can present similarly to AZOOR on UWFFAF and should be highly suspected in cases presenting like AZOOR. [Ophthalmic Surg Lasers Imaging Retina. 2017;48:208-215. ]. Copyright 2017, SLACK Incorporated.

Film cooling air pocket in a closed loop cooled airfoil

DOEpatents

Yu, Yufeng Phillip; Itzel, Gary Michael; Osgood, Sarah Jane; Bagepalli, Radhakrishna; Webbon, Waylon Willard; Burdgick, Steven Sebastian

2002-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending between them. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. To provide for air film cooing of select portions of the airfoil outer surface, at least one air pocket is defined on a wall of at least one of the cavities. Each air pocket is substantially closed with respect to the cooling medium in the cavity and cooling air pumped to the air pocket flows through outlet apertures in the wall of the airfoil to cool the same.

Coronagraphic Wavefront Control for the ATLAST-9.2m Telescope

NASA Technical Reports Server (NTRS)

Lyon, RIchard G.; Oegerle, William R.; Feinberg, Lee D.; Bolcar, Matthew R.; Dean, Bruce H.; Mosier, Gary E.; Postman, Marc

2010-01-01

The Advanced Technology for Large Aperture Space Telescope (ATLAST) concept was assessed as one of the NASA Astrophysics Strategic Mission Concepts (ASMC) studies. Herein we discuss the 9.2-meter diameter segmented aperture version and its wavefront sensing and control (WFSC) with regards to coronagraphic detection and spectroscopic characterization of exoplanets. The WFSC would consist of at least two levels of sensing and control: (i) an outer coarser level of sensing and control to phase and control the segments and secondary mirror in a manner similar to the James Webb Space Telescope but operating at higher temporal bandwidth, and (ii) an inner, coronagraphic instrument based, fine level of sensing and control for both amplitude and wavefront errors operating at higher temporal bandwidths. The outer loop would control rigid-body actuators on the primary and secondary mirrors while the inner loop would control one or more segmented deformable mirror to suppress the starlight within the coronagraphic field-of view. Herein we discuss the visible nulling coronagraph (VNC) and the requirements it levies on wavefront sensing and control and show the results of closed-loop simulations to assess performance and evaluate the trade space of system level stability versus control bandwidth.

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed Central

Baylor, D A; Nunn, B J; Schnapf, J L

1984-01-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output. PMID:6512705

The photocurrent, noise and spectral sensitivity of rods of the monkey Macaca fascicularis.

PubMed

Baylor, D A; Nunn, B J; Schnapf, J L

1984-12-01

Visual transduction in rods of the cynomolgus monkey, Macaca fascicularis, was studied by recording membrane current from single outer segments projecting from small pieces of retina. Light flashes evoked transient outward-going photocurrents with saturating amplitudes of up to 34 pA. A flash causing twenty to fifty photoisomerizations gave a response of half the saturating amplitude. The response-stimulus relation was of the form 1-e-x where x is flash strength. The response to a dim flash usually had a time to peak of 150-250 ms and resembled the impulse response of a series of six low-pass filters. From the average spectral sensitivity of ten rods the rhodopsin was estimated to have a peak absorption near 491 nm. The spectral sensitivity of the rods was in good agreement with the average human scotopic visibility curve determined by Crawford (1949), when the human curve was corrected for lens absorption and self-screening of rhodopsin. Fluctuations in the photocurrent evoked by dim lights were consistent with a quantal event about 0.7 pA in peak amplitude. A steady light causing about 100 photoisomerizations s-1 reduced the flash sensitivity to half the dark-adapted value. At higher background levels the rod rapidly saturated. These results support the idea that dim background light desensitizes human scotopic vision by a mechanism central to the rod outer segments while scotopic saturation may occur within the outer segments. Recovery of the photocurrent after bright flashes was marked by quantized step-like events. The events had the properties expected if bleached rhodopsin in the disks occasionally caused an abrupt blockage of the dark current over about one-twentieth of the length of the outer segment. It is suggested that superposition of these events after bleaching may contribute to the threshold elevation measured psychophysically. The current in darkness showed random fluctuations which disappeared in bright light. The continuous component of the noise had a variance of about 0.03 pA2 and a power spectrum that fell to half near 3 Hz. A second component, consisting of discrete events resembling single-photon responses, was estimated to occur at a rate of 0.006 s-1. It is suggested that the continuous component of the noise may be removed from scotopic vision by a thresholding operation near the rod output.

Kinetics and components of the flash photocurrent of isolated retinal rods of the larval salamander, Ambystoma tigrinum.

PubMed Central

Cobbs, W H; Pugh, E N

1987-01-01

1. Membrane currents initiated by intense, 20 microseconds flashes (photocurrents) were recorded from isolated salamander rods by combined extracellular suction electrodes and intracellular tight-seal electrodes either in current or voltage clamp mode. The magnitudes (mean +/- 2 S.E.M.) of the maximal photoresponses recorded by the suction and by the intracellular electrode respectively were 40 +/- 5 pA (n = 18) and 35 +/- 7 mV (n = 8) for current clamp at zero current; 43 +/- 9 pA and 66 +/- 13 (n = 11) pA for voltage clamp at the zero-current holding potential, -24 +/- 3 mV. 2. Photocurrents initiated by flashes isomerizing 0.1% or more of the outer segment's rhodopsin achieved a saturated velocity and were 95% complete in less than 50 ms. The effect of incrementing flash intensity above 0.1% isomerization can be described as a translation of the photocurrent along the time axis towards the origin. Within the interval 0-50 ms the latter two-thirds of the velocity-saturated photocurrent is well described as a single-exponential decay. The decay was much faster in voltage clamp (2.8 +/- 1.2 ms, n = 11) than in current clamp mode (17 +/- 5 ms, n = 17). 3. The initial third of the velocity-saturated photocurrent, occurring over the interval from the flash to the onset of exponential decay, followed about the same time course in current and voltage clamp. The time interval occupied by this initial 'latent' phase decreased with increasing flash intensity and attained an apparent minimum of about 7 ms in response to flashes isomerizing 10% or more of the rhodopsin at ca. 22 degrees C. 4. The hypothesis that the decay of outer segment light-sensitive membrane current is the same in current and voltage clamp was supported by an analysis of the difference between outer segment currents measured successively in the two recording modes. First, the tail of the difference current decayed exponentially with a time constant approximately equal to R x C, where R and C are independently estimated slope resistance and capacitance of the rod. Secondly, the integral of the difference current, when divided by outer segment capacitance, closely approximated the hyperpolarizing light response measured under current clamp. Thus, displacement current accounted for the difference between photocurrents measured in current and voltage clamp.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2832596

Fine structure of the retinal photoreceptors of the great horned owl (Bubo virginianus).

PubMed

Braekevelt, C R

1993-01-01

The retinal photoreceptors of the great horned owl (Bubo virginianus) consist of rods, single cones and unequal double cones present in a ratio of about 30:1.2. In the light-adapted state the rods are stout cells which are not felt to undergo retinomotor movements. The rod outer segment consists of a stack of scalloped membranous discs enclosed by the cell membrane. The rod inner segment shows an ellipsoid of mitochondria and a wealth of rough endoplasmic reticulum (RER) and polysomes, Golgi zones and autophagic vacuoles but not hyperboloid of glycogen. Single cones show a slightly tapered outer segment, a heterogenous oil droplet and an ellipsoid of mitochondria at the apex of the inner segment. Double cones consist of a larger chief member which also displays an oil droplet and a slightly smaller accessory member which does not. Both members of the double cone as well as the single cone show a prominent ellipsoid, plentiful polysomes and RER and Golgi zones in the inner segment. Neither single nor double cones possess a condensed paraboloid of glycogen but instead show plentiful scattered glycogen particles. Along the contiguous membranes between accessory and chief cones a few presumed junctional complexes are seen near the external limiting membrane. Judging by their morphology in light-adaptation the cones of this species do not undergo photomechanical movements. Rods and cones (both types) have both invaginated (ribbon) and numerous superficial (conventional) synaptic sites. Rods are more numerous in this nocturnally active bird than is usually noted in avian species.

FUEL ELEMENT FOR NUCLEAR REACTORS

DOEpatents

Bassett, C.H.

1961-05-01

A nuclear reactor fuel element comprising high density ceramic fissionable material enclosed in a tubular cladding of corrosion-resistant material is described. The fissionable material is in the form of segments of a tube which have cooperating tapered interfaces which produce outward radial displacement when the segments are urged axially together. A resilient means is provided within the tubular housing to constantly urge the fuel segments axially. This design maintains the fuel material in tight contacting engagement against the inner surface of the outer cladding tube to eliminate any gap therebetween which may be caused by differential thermal expansion between the fuel material and the material of the tube.

Apparatus and methods for impingement cooling of an undercut region adjacent a side wall of a turbine nozzle segment

DOEpatents

Burdgick, Steven Sebastian; Itzel, Gary Michael

2001-01-01

A gas turbine nozzle segment has outer and inner bands. Each band includes a side wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. The inturned flange has a plurality of apertures for directing cooling steam to cool the side wall between adjacent nozzle segments.

Emergence of Functional Hierarchy in a Multiple Timescale Neural Network Model: A Humanoid Robot Experiment

PubMed Central

Yamashita, Yuichi; Tani, Jun

2008-01-01

It is generally thought that skilled behavior in human beings results from a functional hierarchy of the motor control system, within which reusable motor primitives are flexibly integrated into various sensori-motor sequence patterns. The underlying neural mechanisms governing the way in which continuous sensori-motor flows are segmented into primitives and the way in which series of primitives are integrated into various behavior sequences have, however, not yet been clarified. In earlier studies, this functional hierarchy has been realized through the use of explicit hierarchical structure, with local modules representing motor primitives in the lower level and a higher module representing sequences of primitives switched via additional mechanisms such as gate-selecting. When sequences contain similarities and overlap, however, a conflict arises in such earlier models between generalization and segmentation, induced by this separated modular structure. To address this issue, we propose a different type of neural network model. The current model neither makes use of separate local modules to represent primitives nor introduces explicit hierarchical structure. Rather than forcing architectural hierarchy onto the system, functional hierarchy emerges through a form of self-organization that is based on two distinct types of neurons, each with different time properties (“multiple timescales”). Through the introduction of multiple timescales, continuous sequences of behavior are segmented into reusable primitives, and the primitives, in turn, are flexibly integrated into novel sequences. In experiments, the proposed network model, coordinating the physical body of a humanoid robot through high-dimensional sensori-motor control, also successfully situated itself within a physical environment. Our results suggest that it is not only the spatial connections between neurons but also the timescales of neural activity that act as important mechanisms leading to functional hierarchy in neural systems. PMID:18989398

Depressing effect of electroacupuncture on the spinal non-painful sensory input of the rat.

PubMed

Quiroz-González, Salvador; Segura-Alegría, Bertha; Jiménez-Estrada, Ismael

2014-09-01

The aim of this study was to explore the effect of electroacupuncture (EA) applied in the Zusanli (ST36) and Sanyinjiao (SP6) points on the N1 component of the cord dorsum potential (CDP) evoked by electrical stimulation of the sural nerve (SU) in the rat. The experiments were performed in 44 Wistar rats (250-300 g) anesthetized with ketamine (100 mg/kg) and xylazine (2 mg/kg). A bilateral laminectomy was performed to expose the L3 to S2 segments of the spinal cord. The SU nerve was exposed and placed on pairs of hook electrodes for electrical stimulation. The N1-CDPs were recorded with three silver-ball electrodes located on the dorsal surface of the L5 to S1 segments. Ipsilateral high and low EA stimulation (100, 2 Hz, 6 mA, 30 min) induced a considerable reduction in the amplitude (45 ± 5.6, 41 ± 6.2%) of the N1-CDP recorded at the L6 segmental level. Recovery of the N1-CDP amplitude occurred approximately 1-3 s after EA. Sectioning of the saphenous and superficial peroneal nerves reduced the depressing effect provoked by the EA stimulation (18.7 ± 1.3, 27 ± 3.8%). Similarly, sectioning of the posterior and anterior tibial, deep peroneal and gastrocnemius nerves partially reduced the effect provoked by EA (11 ± 1.5, 9.8 ± 1.1, 12.6 ± 1.9%). Intravenous picrotoxin (1 mg/kg) also reduced the action of low and high EA (23 ± 4.8, 27 ± 5.2%). It is suggested that EA stimulation depresses non-painful sensory pathways through the activation of specific inhibitory pathways that receive modulatory actions from other sensory and muscle afferent inputs in the rat spinal cord.

Organization of the spinal trigeminal nucleus in star-nosed moles.

PubMed

Sawyer, Eva K; Leitch, Duncan B; Catania, Kenneth C

2014-10-01

Somatosensory inputs from the face project to multiple regions of the trigeminal nuclear complex in the brainstem. In mice and rats, three subdivisions contain visible representations of the mystacial vibrissae, the principal sensory nucleus, spinal trigeminal subnucleus interpolaris, and subnucleus caudalis. These regions are considered important for touch with high spatial acuity, active touch, and pain and temperature sensation, respectively. Like mice and rats, the star-nosed mole (Condylura cristata) is a somatosensory specialist. Given the visible star pattern in preparations of the star-nosed mole cortex and the principal sensory nucleus, we hypothesized there were star patterns in the spinal trigeminal nucleus subnuclei interpolaris and caudalis. In sections processed for cytochrome oxidase, we found star-like segmentation consisting of lightly stained septa separating darkly stained patches in subnucleus interpolaris (juvenile tissue) and subnucleus caudalis (juvenile and adult tissue). Subnucleus caudalis represented the face in a three-dimensional map, with the most anterior part of the face represented more rostrally than posterior parts of the face. Multiunit electrophysiological mapping was used to map the ipsilateral face. Ray-specific receptive fields in adults matched the CO segmentation. The mean areas of multiunit receptive fields in subnucleus interpolaris and caudalis were larger than previously mapped receptive fields in the mole's principal sensory nucleus. The proportion of tissue devoted to each ray's representation differed between the subnucleus interpolaris and the principal sensory nucleus. Our finding that different trigeminal brainstem maps can exaggerate different parts of the face could provide new insights for the roles of these different somatosensory stations. © 2014 Wiley Periodicals, Inc.

Organization of the spinal trigeminal nucleus in Star-Nosed Moles

PubMed Central

Sawyer, Eva K.; Leitch, Duncan B.; Catania, Kenneth C.

2014-01-01

Somatosensory inputs from the face project to multiple regions of the trigeminal nuclear complex in the brainstem. In mice and rats three subdivisions contain visible representations of the mystacial vibrissae: the principal sensory nucleus, the spinal trigeminal subnucleus interpolaris and subnucleus caudalis. These regions are considered important for touch with high spatial acuity, active touch, and pain and temperature sensation, respectively. Like mice and rats, the star-nosed mole (Condylura cristata) is a somatosensory specialist. Given the visible star pattern in preparations of the star-nosed mole cortex and the principal sensory nucleus, we hypothesized there were star patterns in the spinal trigeminal nucleus subnuclei interpolaris and caudalis. In sections processed for cytochrome oxidase we found star-like segmentation consisting of lightly stained septa separating darkly stained patches in subnucleus interpolaris (juvenile tissue) and subnucleus caudalis (juvenile and adult tissue). Subnucleus caudalis represented the face in a three-dimensional map with the most anterior part of the face represented more rostrally than posterior parts of the face. Multi-unit electrophysiological mapping was used to map the ipsilateral face. Ray-specific receptive fields in adults matched the CO-segmentation. The mean areas of multiunit receptive fields in subnucleus interpolaris and caudalis were larger than previously mapped receptive fields in the mole's principal sensory nucleus. The proportion of tissue devoted to each ray's representation differed between subnucleus interpolaris and the principal sensory nucleus. Our finding that different trigeminal brainstem maps can exaggerate different parts of the face could provide new insights for the roles of these different somatosensory stations. PMID:24715542

End-to-side neurorrhaphy repairs peripheral nerve injury: sensory nerve induces motor nerve regeneration.

PubMed

Yu, Qing; Zhang, She-Hong; Wang, Tao; Peng, Feng; Han, Dong; Gu, Yu-Dong

2017-10-01

End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a nerve. It involves suturing the distal stump of the disconnected nerve (recipient nerve) to the side of the intimate adjacent nerve (donor nerve). However, the motor-sensory specificity after end-to-side neurorrhaphy remains unclear. This study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side neurorrhaphy. Thirty rats were randomized into three groups: (1) end-to-side neurorrhaphy using the ulnar nerve (mixed sensory and motor) as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve; (2) the sham group: ulnar nerve and cutaneous antebrachii medialis nerve were just exposed; and (3) the transected nerve group: cutaneous antebrachii medialis nerve was transected and the stumps were turned over and tied. At 5 months, acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group, and none of the myelinated axons were stained in either the sham or transected nerve groups. Retrograde fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%. In contrast, no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord segment. These results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy.

End-to-side neurorrhaphy repairs peripheral nerve injury: sensory nerve induces motor nerve regeneration

PubMed Central

Yu, Qing; Zhang, She-hong; Wang, Tao; Peng, Feng; Han, Dong; Gu, Yu-dong

2017-01-01

End-to-side neurorrhaphy is an option in the treatment of the long segment defects of a nerve. It involves suturing the distal stump of the disconnected nerve (recipient nerve) to the side of the intimate adjacent nerve (donor nerve). However, the motor-sensory specificity after end-to-side neurorrhaphy remains unclear. This study sought to evaluate whether cutaneous sensory nerve regeneration induces motor nerves after end-to-side neurorrhaphy. Thirty rats were randomized into three groups: (1) end-to-side neurorrhaphy using the ulnar nerve (mixed sensory and motor) as the donor nerve and the cutaneous antebrachii medialis nerve as the recipient nerve; (2) the sham group: ulnar nerve and cutaneous antebrachii medialis nerve were just exposed; and (3) the transected nerve group: cutaneous antebrachii medialis nerve was transected and the stumps were turned over and tied. At 5 months, acetylcholinesterase staining results showed that 34% ± 16% of the myelinated axons were stained in the end-to-side group, and none of the myelinated axons were stained in either the sham or transected nerve groups. Retrograde fluorescent tracing of spinal motor neurons and dorsal root ganglion showed the proportion of motor neurons from the cutaneous antebrachii medialis nerve of the end-to-side group was 21% ± 5%. In contrast, no motor neurons from the cutaneous antebrachii medialis nerve of the sham group and transected nerve group were found in the spinal cord segment. These results confirmed that motor neuron regeneration occurred after cutaneous nerve end-to-side neurorrhaphy. PMID:29171436

Load-resistant coaxial transmission line

DOEpatents

Hall, David R.; Fox, Joe

2006-01-03

A transmission line for downhole tools that make up all or part of a tool string for drilling and production of oil, gas, and geothermal wells that can withstand the dynamic gravitational forces and other accelerations associated with downhole excavations. The transmission line has a metal tube, or outer conductor, that houses a coaxial wire inner conductor. A non-metallic dielectric material is interposed between the inner and outer conductors. The outer and inner conductors and the dielectric are sufficiently compressed together so that independent motion between them is abated. Compression of the components of the transmission line may be achieved by drawing the transmission through one or more dies in order to draw down the outer conductor onto the dielectric, or by expanding the inner conductor against the dielectric using a mandrel or hydraulic pressure. Non-metallic bead segments may be used in aid of the compression necessary to resist the dynamic forces and accelerations of drilling.

A hybrid method for airway segmentation and automated measurement of bronchial wall thickness on CT.

PubMed

Xu, Ziyue; Bagci, Ulas; Foster, Brent; Mansoor, Awais; Udupa, Jayaram K; Mollura, Daniel J

2015-08-01

Inflammatory and infectious lung diseases commonly involve bronchial airway structures and morphology, and these abnormalities are often analyzed non-invasively through high resolution computed tomography (CT) scans. Assessing airway wall surfaces and the lumen are of great importance for diagnosing pulmonary diseases. However, obtaining high accuracy from a complete 3-D airway tree structure can be quite challenging. The airway tree structure has spiculated shapes with multiple branches and bifurcation points as opposed to solid single organ or tumor segmentation tasks in other applications, hence, it is complex for manual segmentation as compared with other tasks. For computerized methods, a fundamental challenge in airway tree segmentation is the highly variable intensity levels in the lumen area, which often causes a segmentation method to leak into adjacent lung parenchyma through blurred airway walls or soft boundaries. Moreover, outer wall definition can be difficult due to similar intensities of the airway walls and nearby structures such as vessels. In this paper, we propose a computational framework to accurately quantify airways through (i) a novel hybrid approach for precise segmentation of the lumen, and (ii) two novel methods (a spatially constrained Markov random walk method (pseudo 3-D) and a relative fuzzy connectedness method (3-D)) to estimate the airway wall thickness. We evaluate the performance of our proposed methods in comparison with mostly used algorithms using human chest CT images. Our results demonstrate that, on publicly available data sets and using standard evaluation criteria, the proposed airway segmentation method is accurate and efficient as compared with the state-of-the-art methods, and the airway wall estimation algorithms identified the inner and outer airway surfaces more accurately than the most widely applied methods, namely full width at half maximum and phase congruency. Copyright © 2015. Published by Elsevier B.V.

Cerebrovascular plaque segmentation using object class uncertainty snake in MR images

NASA Astrophysics Data System (ADS)

Das, Bipul; Saha, Punam K.; Wolf, Ronald; Song, Hee Kwon; Wright, Alexander C.; Wehrli, Felix W.

2005-04-01

Atherosclerotic cerebrovascular disease leads to formation of lipid-laden plaques that can form emboli when ruptured causing blockage to cerebral vessels. The clinical manifestation of this event sequence is stroke; a leading cause of disability and death. In vivo MR imaging provides detailed image of vascular architecture for the carotid artery making it suitable for analysis of morphological features. Assessing the status of carotid arteries that supplies blood to the brain is of primary interest to such investigations. Reproducible quantification of carotid artery dimensions in MR images is essential for plaque analysis. Manual segmentation being the only method presently makes it time consuming and sensitive to inter and intra observer variability. This paper presents a deformable model for lumen and vessel wall segmentation of carotid artery from MR images. The major challenges of carotid artery segmentation are (a) low signal-to-noise ratio, (b) background intensity inhomogeneity and (c) indistinct inner and/or outer vessel wall. We propose a new, effective object-class uncertainty based deformable model with additional features tailored toward this specific application. Object-class uncertainty optimally utilizes MR intensity characteristics of various anatomic entities that enable the snake to avert leakage through fuzzy boundaries. To strengthen the deformable model for this application, some other properties are attributed to it in the form of (1) fully arc-based deformation using a Gaussian model to maximally exploit vessel wall smoothness, (2) construction of a forbidden region for outer-wall segmentation to reduce interferences by prominent lumen features and (3) arc-based landmark for efficient user interaction. The algorithm has been tested upon T1- and PD- weighted images. Measures of lumen area and vessel wall area are computed from segmented data of 10 patient MR images and their accuracy and reproducibility are examined. These results correspond exceptionally well with manual segmentation completed by radiology experts. Reproducibility of the proposed method is estimated for both intra- and inter-operator studies.

The nerve supply of the lumbar intervertebral disc.

PubMed

Edgar, M A

2007-09-01

The anatomical studies, basic to our understanding of lumbar spine innervation through the sinu-vertebral nerves, are reviewed. Research in the 1980s suggested that pain sensation was conducted in part via the sympathetic system. These sensory pathways have now been clarified using sophisticated experimental and histochemical techniques confirming a dual pattern. One route enters the adjacent dorsal root segmentally, whereas the other supply is non-segmental ascending through the paravertebral sympathetic chain with re-entry through the thoracolumbar white rami communicantes. Sensory nerve endings in the degenerative lumbar disc penetrate deep into the disrupted nucleus pulposus, insensitive in the normal lumbar spine. Complex as well as free nerve endings would appear to contribute to pain transmission. The nature and mechanism of discogenic pain is still speculative but there is growing evidence to support a 'visceral pain' hypothesis, unique in the muscloskeletal system. This mechanism is open to 'peripheral sensitisation' and possibly 'central sensitisation' as a potential cause of chronic back pain.

Determination of Exterior Orientation Parameters Through Direct Geo-Referencing in a Real-Time Aerial Monitoring System

NASA Astrophysics Data System (ADS)

Kim, H.; Lee, J.; Choi, K.; Lee, I.

2012-07-01

Rapid responses for emergency situations such as natural disasters or accidents often require geo-spatial information describing the on-going status of the affected area. Such geo-spatial information can be promptly acquired by a manned or unmanned aerial vehicle based multi-sensor system that can monitor the emergent situations in near real-time from the air using several kinds of sensors. Thus, we are in progress of developing such a real-time aerial monitoring system (RAMS) consisting of both aerial and ground segments. The aerial segment acquires the sensory data about the target areas by a low-altitude helicopter system equipped with sensors such as a digital camera and a GPS/IMU system and transmits them to the ground segment through a RF link in real-time. The ground segment, which is a deployable ground station installed on a truck, receives the sensory data and rapidly processes them to generate ortho-images, DEMs, etc. In order to generate geo-spatial information, in this system, exterior orientation parameters (EOP) of the acquired images are obtained through direct geo-referencing because it is difficult to acquire coordinates of ground points in disaster area. The main process, since the data acquisition stage until the measurement of EOP, is discussed as follows. First, at the time of data acquisition, image acquisition time synchronized by GPS time is recorded as part of image file name. Second, the acquired data are then transmitted to the ground segment in real-time. Third, by processing software for ground segment, positions/attitudes of acquired images are calculated through a linear interpolation using the GPS time of the received position/attitude data and images. Finally, the EOPs of images are obtained from position/attitude data by deriving the relationships between a camera coordinate system and a GPS/IMU coordinate system. In this study, we evaluated the accuracy of the EOP decided by direct geo-referencing in our system. To perform this, we used the precisely calculated EOP through the digital photogrammetry workstation (DPW) as reference data. The results of the evaluation indicate that the accuracy of the EOP acquired by our system is reasonable in comparison with the performance of GPS/IMU system. Also our system can acquire precise multi-sensory data to generate the geo-spatial information in emergency situations. In the near future, we plan to complete the development of the rapid generation system of the ground segment. Our system is expected to be able to acquire the ortho-image and DEM on the damaged area in near real-time. Its performance along with the accuracy of the generated geo-spatial information will also be evaluated and reported in the future work.

KSC-08pd3567

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, workers from NASA's Glenn Research Center remove the blue shrink-wrapped covers on these Ares I-X upper stage simulator segments. The protective covers were used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

KSC-08pd3566

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, workers from NASA's Glenn Research Center remove the blue shrink-wrapped covers on these Ares I-X upper stage simulator segments. The protective covers were used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

KSC-08pd3568

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, workers from NASA's Glenn Research Center remove the blue shrink-wrapped covers on these Ares I-X upper stage simulator segments. The protective covers were used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

KSC-08pd3569

NASA Image and Video Library

2008-11-06

CAPE CANAVERAL, Fla. – Inside the Vehicle Assembly Building high bay 4 at NASA's Kennedy Space Center in Florida, workers from NASA's Glenn Research Center remove the blue shrink-wrapped covers on these Ares I-X upper stage simulator segments. The protective covers were used for shipping. The upper stage simulator will be used in the test flight identified as Ares I-X in 2009. The segments will simulate the mass and the outer mold line and will be more than 100 feet of the total vehicle height of 327 feet. The simulator comprises 11 segments that are approximately 18 feet in diameter. Most of the segments will be approximately 10 feet high, ranging in weight from 18,000 to 60,000 pounds, for a total of approximately 450,000 pounds. Photo credit: NASA/Troy Cryder

Exploring photoreceptor reflectivity via multimodal imaging of outer retinal tubulation in advanced age-related macular degeneration

PubMed Central

Litts, Katie M.; Wang, Xiaolin; Clark, Mark E.; Owsley, Cynthia; Freund, K. Bailey; Curcio, Christine A.; Zhang, Yuhua

2016-01-01

Purpose To investigate the microscopic structure of outer retinal tubulation (ORT) and optical properties of cone photoreceptors in vivo, we studied ORT appearance by multimodal imaging, including spectral domain optical coherence tomography (SD-OCT) and adaptive optics scanning laser ophthalmoscopy (AOSLO). Methods Four eyes of 4 subjects with advanced AMD underwent color fundus photography, infrared reflectance imaging, SD-OCT, and AOSLO with a high-resolution research instrument. ORT was identified in closely spaced (11 μm) SD-OCT volume scans. Results ORT in cross-sectional and en face SD-OCT was a hyporeflective area representing a lumen surrounded by a hyperreflective border consisting of cone photoreceptor mitochondria and external limiting membrane, per previous histology. In contrast, ORT by AOSLO was a hyporeflective structure of the same shape as in en face SD-OCT but lacking visualizable cone photoreceptors. Conclusion Lack of ORT cone reflectivity by AOSLO indicates that cones have lost their normal directionality and waveguiding property due to loss of outer segments and subsequent retinal remodeling. Reflective ORT cones by SD-OCT, in contrast, may depend partly on mitochondria as light scatterers within inner segments of these degenerating cells, a phenomenon enhanced by coherent imaging. Multimodal imaging of ORT provides insight into cone degeneration and reflectivity sources in OCT. PMID:27584549

Retinal pigment epithelial dystrophy in Briard dogs.

PubMed

Lightfoot, R M; Cabral, L; Gooch, L; Bedford, P G; Boulton, M E

1996-01-01

The eyes of normal Briard dogs, Briards affected with inherited retinal pigment epithelial dystrophy (RPED) and a range of normal crossbred and beagle dogs were examined and the histopathology of RPED in the Briard was compared with the histopathological features of ageing in the normal canine retina. RPED was characterised by the accumulation of auto-fluorescent lipofuscin-like inclusions in the retinal pigment epithelium (RPE), which initially involved only non-pigmented RPE cells overlying the tapetum but subsequently spread to all pigmented RPE cells. Secondary neuro-retinal degeneration was characterised by a gradual loss of the outer nuclear layer and the subsequent atrophy and degeneration of the inner retina. The loss of primary photoreceptors in the peripheral retina was accompanied by the migration of photoreceptor nuclei and appeared to resemble severe changes due to ageing. Intra-vitreal radiolabelled leucine was used to examine the rate of turnover of the outer segments of the rods in some Briards, but no significant variations were found. The activity of acid phosphatase in RPE was assayed in vitro and showed comparable regional variations in Briard and crossbred dogs. The results suggest that RPED in the Briard is unlikely to be due either to an increased rate of turnover of rod outer segments (and thus an increased phagocytic load) or to a primary insufficiency of lysosomal enzyme.

Classical and alternative complement activation on photoreceptor outer segments drives monocyte-dependent retinal atrophy.

PubMed

Katschke, Kenneth J; Xi, Hongkang; Cox, Christian; Truong, Tom; Malato, Yann; Lee, Wyne P; McKenzie, Brent; Arceo, Rommel; Tao, Jianhua; Rangell, Linda; Reichelt, Mike; Diehl, Lauri; Elstrott, Justin; Weimer, Robby M; Campagne, Menno van Lookeren

2018-05-09

Geographic atrophy (GA), the advanced form of dry age-related macular degeneration (AMD), is characterized by progressive loss of retinal pigment epithelium cells and photoreceptors in the setting of characteristic extracellular deposits and remains a serious unmet medical need. While genetic predisposition to AMD is dominated by polymorphisms in complement genes, it remains unclear how complement activation contributes to retinal atrophy. Here we demonstrate that complement is activated on photoreceptor outer segments (POS) in the retina peripheral to atrophic lesions associated with GA. When exposed to human serum following outer blood-retinal barrier breakdown, POS act as potent activators of the classical and alternative complement pathway. In mouse models of retinal degeneration, classical and alternative pathway complement activation on photoreceptors contributed to the loss of photoreceptor function. This was dependent on C5a-mediated recruitment of peripheral blood monocytes but independent of resident microglia. Genetic or pharmacologic inhibition of both classical and alternative complement C3 and C5 convertases was required to reduce progressive degeneration of photoreceptor rods and cones. Our study implicates systemic classical and alternative complement proteins and peripheral blood monocytes as critical effectors of localized retinal degeneration with potential relevance for the contribution of complement activation to GA.

Diagnostic lumbosacral segmental nerve blocks with local anesthetics: a prospective double-blind study on the variability and interpretation of segmental effects.

PubMed

Wolff, A P; Groen, G J; Crul, B J

2001-01-01

Selective spinal nerve infiltration blocks are used diagnostically in patients with chronic low back pain radiating into the leg. Generally, a segmental nerve block is considered successful if the pain is reduced substantially. Hypesthesia and elicited paresthesias coinciding with the presumed segmental level are used as controls. The interpretation depends on a standard dermatomal map. However, it is not clear if this interpretation is reliable enough, because standard dermatomal maps do not show the overlap of neighboring dermatomes. The goal of the present study is to establish if dissimilarities exist between areas of hypesthesia, spontaneous pain reported by the patient, pain reduction by local anesthetics, and paresthesias elicited by sensory electrostimulation. A secondary goal is to determine to what extent the interpretation is improved when the overlaps of neighboring dermatomes are taken into account. Patients suffering from chronic low back pain with pain radiating into the leg underwent lumbosacral segmental nerve root blocks at subsequent levels on separate days. Lidocaine (2%, 0.5 mL) mixed with radiopaque fluid (0.25 mL) was injected after verifying the target location using sensory and motor electrostimulation. Sensory changes (pinprick method), paresthesias (reported by the patient), and pain reduction (Numeric Rating Scale) were reported. Hypesthesia and paresthesias were registered in a standard dermatomal map and in an adapted map which included overlap of neighboring dermatomes. The relationships between spinal level of injection, extent of hypesthesia, location of paresthesias, and corresponding dermatome were assessed quantitatively. Comparison of the results between both dermatomal maps was done by paired t-tests. After inclusion, data were processed for 40 segmental nerve blocks (L2-S1) performed in 29 patients. Pain reduction was achieved in 43%. Hypesthetic areas showed a large variability in size and location, and also in comparison to paresthesias. Mean hypesthetic area amounted 2.7 +/- 1.4 (+/- SD: range, 0 to 6; standard map) and 3.6 +/- 1.8 (0 to 6; adapted map; P <.001) dermatomes. In these cases, hypesthesia in the corresponding dermatome was found in 80% (standard map) and 88% of the cases (adapted map, not significant). Paresthesias occurring in the corresponding dermatome were found in 80% (standard map) compared with 98% (adapted map, P <.001). In 85% (standard map) and 88% (adapted map), spontaneous pain was present in the dermatome corresponding to the level of local anesthetic injection. In 55% (standard map) versus 75% (adapted map, P <.005), a combination of spontaneous pain, hypesthesia, and paresthesias was found in the corresponding dermatome. Hypesthetic areas determined after lumbosacral segmental nerve blocks show a large variability in size and location compared with elicited paresthesias. Confirmation of an adequately performed segmental nerve block, determined by coexistence of hypesthesia, elicited paresthesias and pain in the presumed dermatome, is more reliable when the overlap of neighboring dermatomes is taken into account.

Scanning electron microscopy of echinoid podia.

PubMed

Florey, E; Cahill, M A

1982-01-01

Tube feet of the sea urchin Strongylocentrotus franciscanus were studied with the scanning electron microscope (SEM). By use of fractured preparations it was possible to obtain views of all components of the layered tube-foot wall. The outer epithelium was found to bear tufts of cilia possibly belonging to sensory cells. The nerve plexus was clearly revealed as being composed of bundles of varicose axons. The basal lamina, which covers the outer and inner surfaces of the connective tissue layer, was found to be a mechanically resistant and elastic membrane. The connective tissue appears as dense bundles of (collagen) fibers. The luminal epithelium (coelothelium) is a single layer of flagellated collar cells. There is no indication that the muscle fibers, which insert on the inner basal lamina of the connective tissue layer are innervated by axons from the basi-epithelial nerve plexus. The results agree with previous conclusions concerning tube-foot structure based on transmission electron microscopy, and provide additional information, particularly with regard to the outer and inner epithelia.

Effects of ionizing radiation on the light sensing elements of the retina. [Structural and physiological effects of carbon, helium, and neon ions on rods and cones of salamanders and mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Malachowski, M.J.

1978-07-01

This investigation was undertaken to quantitate possible morphological and physiological effects of particles of high linear energy transfer on the retina, in comparison with x-ray effects. The particles used were accelerated atomic nuclei of helium, carbon, and neon at kinetic energies of several hundred MeV/nucleon. For morphological studies, scanning and transmission electron microscopy and light microscopy were used. Physiological studies consisted of autoradiographic data of the rate of incorporation of labeled protein in the structures (opsin) of the outer segment of visual cells. Structural changes were found in the nuclei, as well as the inner and outer segments of visualmore » cells, rods and cones. At a low dose of 10 rad, x rays and helium had no statistically significant morphological effects, but carbon and neon beams did cause significant degeneration of individual cells, pointing to the existence of a linear dose--effect relationship. At high doses of several hundred rads, a Pathologic Index determined the relative biological effectiveness of neon against alpha particles to have a value of greater than 6. The severity of effects per particle increased with atomic number. Labeling studies demonstrated a decreased rate of incorporation of labeled proteins in the structural organization of the outer segments of visual rods. The rate of self-renewal of visual rod discs was punctuated by irradiation and the structures themselves were depleted of amino acids. A model of rod discs (metabolic and catabolic) was postulated for correlated early and late effects to high and low doses.« less

Biochemical Measurements of Free Opsin in Macular Degeneration Eyes: Examining the 11-CIS Retinal Deficiency Hypothesis of Delayed Dark Adaptation (An American Ophthalmological Society Thesis).

PubMed

Hanneken, Anne; Neikirk, Thomas; Johnson, Jennifer; Kono, Masahiro

2017-08-01

To test the hypothesis that delayed dark adaptation in patients with macular degeneration is due to an excess of free unliganded opsin (apo-opsin) and a deficiency of the visual chromophore, 11 -cis retinal, in rod outer segments. A total of 50 human autopsy eyes were harvested from donors with and without macular degeneration within 2-24 hrs. postmortem. Protocols were developed which permitted dark adaptation of normal human eyes after death and enucleation. Biochemical methods of purifying rod outer segments were optimized and the concentration of rhodopsin and apo-opsin was measured with UV-visible scanning spectroscopy. The presence of apo-opsin was calculated by measuring the difference in the rhodopsin absorption spectra before and after the addition of 11 -cis retinal. A total of 20 normal eyes and 16 eyes from donors with early, intermediate and advanced stages of macular degeneration were included in the final analysis. Dark adaptation was achieved by harvesting whole globes in low light, transferring into dark (light-proof) canisters and dissecting the globes using infrared light and image converters for visualization. Apo-opsin was readily detected in positive controls after the addition of 11 -cis retinal. Normal autopsy eyes showed no evidence of apo-opsin. Eyes with macular degeneration also showed no evidence of apo-opsin, regardless of the severity of disease. Methods have been developed to study dark adaptation in human autopsy eyes. Eyes with age-related macular degeneration do not show a deficiency of 11 -cis retinal or an excess of apo-opsin within rod outer segments.

An inducible amphipathic helix within the intrinsically disordered C terminus can participate in membrane curvature generation by peripherin-2/rds.

PubMed

Milstein, Michelle L; Kimler, Victoria A; Ghatak, Chiranjib; Ladokhin, Alexey S; Goldberg, Andrew F X

2017-05-12

Peripherin-2/rds is required for biogenesis of vertebrate photoreceptor outer segment organelles. Its localization at the high-curvature rim domains of outer segment disk membranes suggests that it may act to shape these structures; however, the molecular function of this protein is not yet resolved. Here, we apply biochemical, biophysical, and imaging techniques to elucidate the role(s) played by the protein's intrinsically disordered C-terminal domain and an incipient amphipathic α-helix contained within it. We investigated a deletion mutant lacking only this α-helix in stable cell lines and Xenopus laevis photoreceptors. We also studied a soluble form of the full-length ∼7-kDa cytoplasmic C terminus in cultured cells and purified from Escherichia coli The α-helical motif was not required for protein biosynthesis, tetrameric subunit assembly, tetramer polymerization, localization at disk rims, interaction with GARP2, or the generation of membrane curvature. Interestingly, however, loss of the helical motif up-regulated membrane curvature generation in cellulo , introducing the possibility that it may regulate this activity in photoreceptors. Furthermore, the incipient α-helix (within the purified soluble C terminus) partitioned into membranes only when its acidic residues were neutralized by protonation. This suggests that within the context of full-length peripherin-2/rds, partitioning would most likely occur at a bilayer interfacial region, potentially adjacent to the protein's transmembrane domains. In sum, this study significantly strengthens the evidence that peripherin-2/rds functions directly to shape the high-curvature rim domains of the outer segment disk and suggests that the protein's C terminus may modulate membrane curvature-generating activity present in other protein domains. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

Rod outer segment retinol formation is independent of Abca4, arrestin, rhodopsin kinase, and rhodopsin palmitylation.

PubMed

Blakeley, Lorie R; Chen, Chunhe; Chen, Ching-Kang; Chen, Jeannie; Crouch, Rosalie K; Travis, Gabriel H; Koutalos, Yiannis

2011-06-01

The reactive aldehyde all-trans retinal is released in rod photoreceptor outer segments by photoactivated rhodopsin and is eliminated through reduction to all-trans retinol. This study was undertaken to determine whether all-trans retinol formation depends on Abca4, arrestin, rhodopsin kinase, and the palmitylation of rhodopsin, all of which are factors that affect the release and sequestration of all-trans retinal. Experiments were performed in isolated retinas and single living rods derived from 129/sv wild-type mice and Abca4-, arrestin-, and rhodopsin kinase-deficient mice and in genetically modified mice containing unpalmitylated rhodopsin. Formation of all-trans retinol was measured by imaging its fluorescence and by HPLC of retina extracts. The release of all-trans retinal from photoactivated rhodopsin was measured in purified rod outer segment membranes according to the increase in tryptophan fluorescence. All experiments were performed at 37°C. The kinetics of all-trans retinol formation in the different types of genetically modified mice are in reasonable agreement with those in wild-type animals. The kinetics of all-trans retinol formation in 129/sv mice are similar to those in C57BL/6, although the latter are known to regenerate rhodopsin much more slowly. The release of all-trans retinal from rhodopsin in purified membranes is significantly faster than the formation of all-trans retinol in intact cells and is independent of the presence of the palmitate groups. The regeneration of rhodopsin and the recycling of its chromophore are not strongly coupled. Neither the activities of Abca4, rhodopsin kinase, and arrestin, nor the palmitylation of rhodopsin affects the formation of all-trans retinol.

Concentric retinitis pigmentosa: clinicopathologic correlations.

PubMed

Milam, A H; De Castro, E B; Smith, J E; Tang, W X; John, S K; Gorin, M B; Stone, E M; Aguirre, G D; Jacobson, S G

2001-10-01

Progressive concentric (centripetal) loss of vision is one pattern of visual field loss in retinitis pigmentosa. This study provides the first clinicopathologic correlations for this form of retinitis pigmentosa. A family with autosomal dominant concentric retinitis pigmentosa was examined clinically and with visual function tests. A post-mortem eye of an affected 94 year old family member was processed for histopathology and immunocytochemistry with retinal cell specific antibodies. Unrelated simplex/multiplex patients with concentric retinitis pigmentosa were also examined. Affected family members of the eye donor and patients from the other families had prominent peripheral pigmentary retinopathy with more normal appearing central retina, good visual acuity, concentric field loss, normal or near normal rod and cone sensitivity within the preserved visual field, and reduced rod and cone electroretinograms. The eye donor, at age 90, had good acuity and function in a central island. Grossly, the central region of the donor retina appeared thinned but otherwise normal, while the far periphery contained heavy bone spicule pigment. Microscopically the central retina showed photoreceptor outer segment shortening and some photoreceptor cell loss. The mid periphery had a sharp line of demarcation where more central photoreceptors were near normal except for very short outer segments and peripheral photoreceptors were absent. Rods and cones showed abrupt loss of outer segments and cell death at this interface. It is concluded that concentric retinitis pigmentosa is a rare but recognizable phenotype with slowly progressive photoreceptor death from the far periphery toward the central retina. The disease is retina-wide but shows regional variation in severity of degeneration; photoreceptor death is severe in the peripheral retina with an abrupt edge between viable and degenerate photoreceptors. Peripheral to central gradients of unknown retinal molecule(s) may be defective or modify photoreceptor degeneration in concentric retinitis pigmentosa.

Mfsd2a Is a Transporter for the Essential ω-3 Fatty Acid Docosahexaenoic Acid (DHA) in Eye and Is Important for Photoreceptor Cell Development*

PubMed Central

Wong, Bernice H.; Chan, Jia Pei; Cazenave-Gassiot, Amaury; Poh, Rebecca W.; Foo, Juat Chin; Galam, Dwight L. A.; Ghosh, Sujoy; Nguyen, Long N.; Barathi, Veluchamy A.; Yeo, Sia W.; Luu, Chi D.; Wenk, Markus R.; Silver, David L.

2016-01-01

Eye photoreceptor membrane discs in outer rod segments are highly enriched in the visual pigment rhodopsin and the ω-3 fatty acid docosahexaenoic acid (DHA). The eye acquires DHA from blood, but transporters for DHA uptake across the blood-retinal barrier or retinal pigment epithelium have not been identified. Mfsd2a is a newly described sodium-dependent lysophosphatidylcholine (LPC) symporter expressed at the blood-brain barrier that transports LPCs containing DHA and other long-chain fatty acids. LPC transport via Mfsd2a has been shown to be necessary for human brain growth. Here we demonstrate that Mfsd2a is highly expressed in retinal pigment epithelium in embryonic eye, before the development of photoreceptors, and is the primary site of Mfsd2a expression in the eye. Eyes from whole body Mfsd2a-deficient (KO) mice, but not endothelium-specific Mfsd2a-deficient mice, were DHA-deficient and had significantly reduced LPC/DHA transport in vivo. Fluorescein angiography indicated normal blood-retinal barrier function. Histological and electron microscopic analysis indicated that Mfsd2a KO mice exhibited a specific reduction in outer rod segment length, disorganized outer rod segment discs, and mislocalization of and reduction in rhodopsin early in postnatal development without loss of photoreceptors. Minor photoreceptor cell loss occurred in adult Mfsd2a KO mice, but electroretinography indicated visual function was normal. The developing eyes of Mfsd2a KO mice had activated microglia and up-regulation of lipogenic and cholesterogenic genes, likely adaptations to loss of LPC transport. These findings identify LPC transport via Mfsd2a as an important pathway for DHA uptake in eye and for development of photoreceptor membrane discs. PMID:27008858

New algorithm for detecting smaller retinal blood vessels in fundus images

NASA Astrophysics Data System (ADS)

LeAnder, Robert; Bidari, Praveen I.; Mohammed, Tauseef A.; Das, Moumita; Umbaugh, Scott E.

2010-03-01

About 4.1 million Americans suffer from diabetic retinopathy. To help automatically diagnose various stages of the disease, a new blood-vessel-segmentation algorithm based on spatial high-pass filtering was developed to automatically segment blood vessels, including the smaller ones, with low noise. Methods: Image database: Forty, 584 x 565-pixel images were collected from the DRIVE image database. Preprocessing: Green-band extraction was used to obtain better contrast, which facilitated better visualization of retinal blood vessels. A spatial highpass filter of mask-size 11 was applied. A histogram stretch was performed to enhance contrast. A median filter was applied to mitigate noise. At this point, the gray-scale image was converted to a binary image using a binary thresholding operation. Then, a NOT operation was performed by gray-level value inversion between 0 and 255. Postprocessing: The resulting image was AND-ed with its corresponding ring mask to remove the outer-ring (lens-edge) artifact. At this point, the above algorithm steps had extracted most of the major and minor vessels, with some intersections and bifurcations missing. Vessel segments were reintegrated using the Hough transform. Results: After applying the Hough transform, both the average peak SNR and the RMS error improved by 10%. Pratt's Figure of Merit (PFM) was decreased by 6%. Those averages were better than [1] by 10-30%. Conclusions: The new algorithm successfully preserved the details of smaller blood vessels and should prove successful as a segmentation step for automatically identifying diseases that affect retinal blood vessels.

The gut-brain axis rewired: adding a functional vagal nicotinic "sensory synapse".

PubMed

Perez-Burgos, Azucena; Mao, Yu-Kang; Bienenstock, John; Kunze, Wolfgang A

2014-07-01

It is generally accepted that intestinal sensory vagal fibers are primary afferent, responding nonsynaptically to luminal stimuli. The gut also contains intrinsic primary afferent neurons (IPANs) that respond to luminal stimuli. A psychoactive Lactobacillus rhamnosus (JB-1) that affects brain function excites both vagal fibers and IPANs. We wondered whether, contrary to its primary afferent designation, the sensory vagus response to JB-1 might depend on IPAN to vagal fiber synaptic transmission. We recorded ex vivo single- and multiunit afferent action potentials from mesenteric nerves supplying mouse jejunal segments. Intramural synaptic blockade with Ca(2+) channel blockers reduced constitutive or JB-1-evoked vagal sensory discharge. Firing of 60% of spontaneously active units was reduced by synaptic blockade. Synaptic or nicotinic receptor blockade reduced firing in 60% of vagal sensory units that were stimulated by luminal JB-1. In control experiments, increasing or decreasing IPAN excitability, respectively increased or decreased nerve firing that was abolished by synaptic blockade or vagotomy. We conclude that >50% of vagal afferents function as interneurons for stimulation by JB-1, receiving input from an intramural functional "sensory synapse." This was supported by myenteric plexus nicotinic receptor immunohistochemistry. These data offer a novel therapeutic target to modify pathological gut-brain axis activity.-Perez-Burgos, A., Mao, Y.-K., Bienenstock, J., Kunze, W. A. The gut-brain axis rewired: adding a functional vagal nicotinic "sensory synapse." © FASEB.

High-Resolution Gamma-Ray Imaging Measurements Using Externally Segmented Germanium Detectors

NASA Technical Reports Server (NTRS)

Callas, J.; Mahoney, W.; Skelton, R.; Varnell, L.; Wheaton, W.

1994-01-01

Fully two-dimensional gamma-ray imaging with simultaneous high-resolution spectroscopy has been demonstrated using an externally segmented germanium sensor. The system employs a single high-purity coaxial detector with its outer electrode segmented into 5 distinct charge collection regions and a lead coded aperture with a uniformly redundant array (URA) pattern. A series of one-dimensional responses was collected around 511 keV while the system was rotated in steps through 180 degrees. A non-negative, linear least-squares algorithm was then employed to reconstruct a 2-dimensional image. Corrections for multiple scattering in the detector, and the finite distance of source and detector are made in the reconstruction process.

Stress intensity and displacement coefficients for radially cracked ring segments subject to three-point bending

NASA Technical Reports Server (NTRS)

Gross, B.; Srawley, J. E.

1983-01-01

The boudary collocation method was used to generate Mode 1 stress intensity and crack mouth displacement coefficients for internally and externally radially cracked ring segments (arc bend specimens) subjected to three point radial loading. Numerical results were obtained for ring segment outer to inner radius ratios (R sub o/ R sub i) ranging from 1.10 to 2.50 and crack length to width ratios (a/W) ranging from 0.1 to 0.8. Stress intensity and crack mouth displacement coefficients were found to depend on the ratios R sub o/R sub i and a/W as well as the included angle between the directions of the reaction forces.

Architecture of the human renal inner medulla and functional implications

PubMed Central

Wei, Guojun; Rosen, Seymour; Dantzler, William H.

2015-01-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. PMID:26290371

Spectral domain optical coherence tomography as an effective screening test for hydroxychloroquine retinopathy (the "flying saucer" sign).

PubMed

Chen, Eric; Brown, David M; Benz, Matthew S; Fish, Richard H; Wong, Tien P; Kim, Rosa Y; Major, James C

2010-10-21

While the long-term incidence of hydroxychloroquine (HCQ) retinopathy is low, there remains no definitive clinical screening test to recognize HCQ toxicity before ophthalmoscopic fundus changes or visual symptoms. Patients receiving HCQ were evaluated with spectral domain optical coherence tomography (SD OCT) to assess the feasibility of identifying HCQ retinopathy at an early stage. Twenty-five patients referred for the evaluation of hydroxychloroquine toxicity underwent a comprehensive ocular examination, Humphrey visual field (HVF) perimetry, time domain OCT, and SD OCT. Some patients with screening abnormalities also underwent further diagnostic testing at the discretion of the treating providers. Five patients were found to have SD OCT findings corresponding to HCQ toxicity and retinal damage as seen by clinical exam and/or HVF perimetry. Two patients with advanced toxicity were found to have significant outer retina disruption in the macula on SD OCT. Three patients with early HCQ toxicity and HVF 10-2 perifoveal defects were found to have loss of the perifoveal photoreceptor inner segment/outer segment (IS/OS) junction with intact outer retina directly under the fovea, creating the "flying saucer" sign. While two of these three patients had early ophthalmoscopic fundus changes, one had none. Outer retinal abnormalities including perifoveal photoreceptor IS/OS junction disruption can be identified by SD OCT in early HCQ toxicity, sometimes even before ophthalmoscopic fundus changes are apparent. SD OCT may have a potential complementary role in screening for HCQ retinopathy due to its quick acquisition and because it is more objective than automated perimetry.

FREQUENT SUBCLINICAL MACULAR CHANGES IN COMBINED BRAF/MEK INHIBITION WITH HIGH-DOSE HYDROXYCHLOROQUINE AS TREATMENT FOR ADVANCED METASTATIC BRAF MUTANT MELANOMA: Preliminary Results From a Phase I/II Clinical Treatment Trial.

PubMed

Nti, Akosua A; Serrano, Leona W; Sandhu, Harpal S; Uyhazi, Katherine E; Edelstein, Ilaina D; Zhou, Elaine J; Bowman, Scott; Song, Delu; Gangadhar, Tara C; Schuchter, Lynn M; Mitnick, Sheryl; Huang, Alexander; Nichols, Charles W; Amaravadi, Ravi K; Kim, Benjamin J; Aleman, Tomas S

2018-01-10

To assess the potential ocular toxicity of a combined BRAF inhibition (BRAFi) + MEK inhibition (MEKi) + hydroxychloroquine (HCQ) regime used to treat metastatic BRAF mutant melanoma. Patients with stage IV metastatic melanoma and BRAF V600E mutations (n = 11, 31-68 years of age) were included. Treatment was with oral dabrafenib, 150 mg bid, trametinib, 2 mg/day, and HCQ, 400 mg to 600 mg bid. An ophthalmic examination, spectral domain optical coherence tomography, near-infrared and short-wavelength fundus autofluorescence, and static perimetry were performed at baseline, 1 month, and q/6 months after treatment. There were no clinically significant ocular events; there was no ocular inflammation. The only medication-related change was a separation of the photoreceptor outer segment tip from the apical retinal pigment epithelium that could be traced from the fovea to the perifoveal retina noted in 9/11 (82%) of the patients. There were no changes in retinal pigment epithelium melanization or lipofuscin content by near-infrared fundus autofluorescence and short-wavelength fundus autofluorescence, respectively. There were no inner retinal or outer nuclear layer changes. Visual acuities and sensitivities were unchanged. BRAFi (trametinib) + MEKi (dabrafenib) + HCQ causes very frequent, subclinical separation of the photoreceptor outer segment from the apical retinal pigment epithelium without inner retinal changes or signs of inflammation. The changes suggest interference with the maintenance of the outer retinal barrier and/or phagocytic/pump functions of the retinal pigment epithelium by effective MEK inhibition.

Failed back surgery syndrome: the role of symptomatic segmental single-level instability after lumbar microdiscectomy.

PubMed

Schaller, B

2004-05-01

Segmental instability represents one of several different factors that may cause or contribute to the failed back surgery syndrome after lumbar microdiscectomy. As segmental lumbar instability poses diagnostic problems by lack of clear radiological and clinical criteria, only little is known about the occurrence of this phenomenon following primary microdiscectomy. Retrospectively, the records of 2,353 patients were reviewed according to postoperative symptomatic segmental single-level instability after lumbar microdiscectomy between 1989 and 1997. Progressive neurological deficits increased (mean of 24 months; SD: 12, range 1-70) after the initial surgical procedure in 12 patients. The mean age of the four men and eight women was 43 years (SD: 6, range 40-77). The main symptoms and signs of secondary neurological deterioration were radicular pain in 9 of 12 patients, increased motor weakness in 6 of 12 patients and sensory deficits in 4 of 12 patients. All 12 symptomatic patients had radiological evidence of segmental changes correlating with the clinical symptoms and signs. All but one patient showed a decrease in the disc height greater than 30% at the time of posterior spondylodesis compared with the preoperative images before lumbar microdiscectomy. All patients underwent secondary laminectomy and posterior lumbar sponylodesis. Postoperatively, pain improved in 8 of 9 patients, motor weakness in 3 of 6 patients, and sensory deficits in 2 of 4 patients. During the follow-up period of 72+/-7 months, one patient required a third operation to alleviate spinal stenosis at the upper end of the laminectomy. Patients with secondary segmental instability following microdiscectomy were mainly in their 40s. Postoperative narrowing of the intervertebral space following lumbar microdiscectomy is correlated to the degree of intervertebral disc resection. It can therefore be concluded that (1) patients in their 40s are prone to postoperative narrowing of the intervertebral disc space and hence subsequent intervertebral instability and (2) that a small extent of intervertebral disc resection and preservation of the "segmental frame" may be beneficial in those patients. The present study demonstrated for the first time that the degree of extensive operative techniques in microdiscectomy increased the risk of subsequent segmental instability. In addition, narrowing of the intervertebral space of more than 30% represents a clear radiological sign of segmental instability.

Segmented lasing tube for high temperature laser assembly

DOEpatents

Sawicki, Richard H.; Alger, Terry W.; Finucane, Raymond G.; Hall, Jerome P.

1996-01-01

A high temperature laser assembly capable of withstanding operating temperatures in excess of 1500.degree. C. is described comprising a segmented cylindrical ceramic lasing tube having a plurality of cylindrical ceramic lasing tube segments of the same inner and outer diameters non-rigidly joined together in axial alignment; insulation of uniform thickness surround the walls of the ceramic lasing tube; a ceramic casing, preferably of quartz, surrounding the insulation; and a fluid cooled metal jacket surrounds the ceramic casing. In a preferred embodiment, the inner surface of each of the ceramic lasing tube segments are provided with a pair of oppositely spaced grooves in the wall thereof parallel to the center axis of the segmented cylindrical ceramic lasing tube, and both of the grooves and the center axis of the segmented cylindrical ceramic lasing tube lie in a common plane, with the grooves in each ceramic lasing tube segment in circumferential alignment with the grooves in the adjoining ceramic lasing tube segments; and one or more ceramic plates, all lying in a common plane to one another and with the central axis of the segmented ceramic lasing tube, are received in the grooves to provide additional wall area in the segmented ceramic lasing tube for collision and return to ground state of metastable metal atoms within the segmented ceramic lasing tube.

Identifying the ideal profile of French yogurts for different clusters of consumers.

PubMed

Masson, M; Saint-Eve, A; Delarue, J; Blumenthal, D

2016-05-01

Identifying the sensory properties that affect consumer preferences for food products is an important feature of product development. Different methods, such as external preference mapping or partial least squares regression, are used to establish relationships between sensory data and consumer preferences and to identify sensory attributes that drive consumer preferences, by highlighting optimum products. Plain French yogurts were evaluated by a sensory profiling method performed by 12 trained judges. In parallel, 180 consumers were asked to score their overall liking and complete a cognitive restraint questionnaire. After hierarchical cluster analysis on the liking scores, preference mapping using a quadratic regression model was performed. Five clusters of consumers were identified as a function of different preference patterns. Contrary to our expectations, fat levels were not discriminating. For each cluster, the results of preference mapping enabled the identification of optimum products. A comparison of the 5 sensory profiles revealed numerous differences between key sensory attributes. For example, one consumer cluster had a strong preference for products perceived as very thick, grainy, but with a less flowing texture, less sticky, whey presence and color, in contrast to other clusters. In addition, each segment of consumers was characterized according to the results of the cognitive restraint questionnaire. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Cooling circuit for steam and air-cooled turbine nozzle stage

DOEpatents

Itzel, Gary Michael; Yu, Yufeng

2002-01-01

The turbine vane segment includes inner and outer walls with a vane extending therebetween. The vane includes leading and trailing edge cavities and intermediate cavities. An impingement plate is spaced from the outer wall to impingement-cool the outer wall. Post-impingement cooling air flows through holes in the outer wall to form a thin air-cooling film along the outer wall. Cooling air is supplied an insert sleeve with openings in the leading edge cavity for impingement-cooling the leading edge. Holes through the leading edge afford thin-film cooling about the leading edge. Cooling air is provided the trailing edge cavity and passes through holes in the side walls of the vane for thin-film cooling of the trailing edge. Steam flows through a pair of intermediate cavities for impingement-cooling of the side walls. Post-impingement steam flows to the inner wall for impingement-cooling of the inner wall and returns the post-impingement cooling steam through inserts in other intermediate cavities for impingement-cooling the side walls of the vane.

Adaptations in rod outer segment disc membranes in response to environmental lighting conditions.

PubMed

Rakshit, Tatini; Senapati, Subhadip; Parmar, Vipul M; Sahu, Bhubanananda; Maeda, Akiko; Park, Paul S-H

2017-10-01

The light-sensing rod photoreceptor cell exhibits several adaptations in response to the lighting environment. While adaptations to short-term changes in lighting conditions have been examined in depth, adaptations to long-term changes in lighting conditions are less understood. Atomic force microscopy was used to characterize the structure of rod outer segment disc membranes, the site of photon absorption by the pigment rhodopsin, to better understand how photoreceptor cells respond to long-term lighting changes. Structural properties of the disc membrane changed in response to housing mice in constant dark or light conditions and these adaptive changes required output from the phototransduction cascade initiated by rhodopsin. Among these were changes in the packing density of rhodopsin in the membrane, which was independent of rhodopsin synthesis and specifically affected scotopic visual function as assessed by electroretinography. Studies here support the concept of photostasis, which maintains optimal photoreceptor cell function with implications in retinal degenerations. Copyright © 2017 Elsevier B.V. All rights reserved.

Growth Mechanism of a Unique Hierarchical Vaterite Structure

NASA Astrophysics Data System (ADS)

Ma, Guobin; Xu, Yifei; Wang, Mu

2013-03-01

Calcium carbonate is one of the most significant minerals in nature as well as in biogenic sources. Calcium carbonate occurs naturally in three crystalline polymorphs, i.e., calcite, aragonite, and vaterite. Although it has been attracted much research attention to understanding of the formation mechanisms of the material, the properties of the vaterite polymorph is not well known. Here we report synthesis and formation mechanism of a unique hierarchical structure of vaterite. The material is grown by a controlled diffusion method. The structure possesses a core and an outer part. The core is convex lens-like and is formed by vaterite nanocrystals that have small misorientations. The outer part is separated into six garlic clove-like segments. Each segment possesses piles of plate-like vaterite crystals, and the orientations of the plates continuously change from pile to pile. Based on real-time experimental results and the structural analysis, a growth mechanism is presented. Work supported by NSFC (Grant No. 51172104) and MOST of China (Grant No. 2101CB630705)

A smart sensor architecture based on emergent computation in an array of outer-totalistic cells

NASA Astrophysics Data System (ADS)

Dogaru, Radu; Dogaru, Ioana; Glesner, Manfred

2005-06-01

A novel smart-sensor architecture is proposed, capable to segment and recognize characters in a monochrome image. It is capable to provide a list of ASCII codes representing the recognized characters from the monochrome visual field. It can operate as a blind's aid or for industrial applications. A bio-inspired cellular model with simple linear neurons was found the best to perform the nontrivial task of cropping isolated compact objects such as handwritten digits or characters. By attaching a simple outer-totalistic cell to each pixel sensor, emergent computation in the resulting cellular automata lattice provides a straightforward and compact solution to the otherwise computationally intensive problem of character segmentation. A simple and robust recognition algorithm is built in a compact sequential controller accessing the array of cells so that the integrated device can provide directly a list of codes of the recognized characters. Preliminary simulation tests indicate good performance and robustness to various distortions of the visual field.

Posterior Segment Toxicity Following Gemcitabine and Docetaxel Chemotherapy

PubMed Central

Valeshabad, Ali Kord; Mieler, William F.; Setlur, Vikram; Thomas, Merina; Shahidi, Mahnaz

2015-01-01

Purpose To report outer retinal disruption and uveal effusion following gemcitabine and docetaxel combination therapy. Case Report A 78-year-old woman presented with blurry vision following two cycles of gemcitabine and docetaxel combination chemotherapy for stage IV sarcoma. At presentation, visual acuity (VA) was finger counting and 20/25 in the right and left eyes, respectively. Slit lamp examination and B scan ultrasonography revealed severe uveal effusion in the right eye and choroidal folds in the left eye. Spectral domain optical coherence tomography showed disruption of photoreceptor inner segment ellipsoid band in the right eye. The patient was monitored weekly with ophthalmic examination and B scan ultrasonography, while continuing with gemcitabine monotherapy. At 8 weeks follow up, uveal effusion improved considerably and VA was 20/40 and 20/20 in the right and left eyes, respectively. Conclusions Uveal effusion and outer retinal disruption were reported following gemcitabine and docetaxel chemotherapy. Early detection and close ophthalmic monitoring may allow concurrent cancer treatment and prevention of possible chemotherapy-induced ocular side effects. PMID:25822016

Mutation K42E in dehydrodolichol diphosphate synthase (DHDDS) causes recessive retinitis pigmentosa.

PubMed

Lam, Byron L; Züchner, Stephan L; Dallman, Julia; Wen, Rong; Alfonso, Eduardo C; Vance, Jeffery M; Peričak-Vance, Margaret A

2014-01-01

A single-nucleotide mutation in the gene that encodes DHDDS has been identified by whole exome sequencing as the cause of the non-syndromic recessive retinitis pigmentosa (RP) in a family of Ashkenazi Jewish origin in which three of the four siblings have early onset retinal degeneration. The peripheral retinal degeneration in the affected siblings was evident in the initial examination in 1992 and only one had detectable electroretinogram (ERG) that suggested cone-rod dysfunction. The pigmentary retinal degeneration subsequently progressed rapidly. The identified mutation changes the highly conserved residue Lys42 to Glu, resulting in lower catalytic efficiency. Patterns of plasma transferrin isoelectric focusing gel were normal in all family members, indicating no significant abnormality in protein glycosylation. Dolichols have been shown to influence the fluidity and of the membrane and promote vesicle fusion. Considering that photoreceptor outer segments contain stacks of membrane discs, we believe that the mutation may lead to low dolichol levels in photoreceptor outer segments, resulting in unstable membrane structure that leads to photoreceptor degeneration.

Oil droplets of bird eyes: microlenses acting as spectral filters

PubMed Central

Stavenga, Doekele G.; Wilts, Bodo D.

2014-01-01

An important component of the cone photoreceptors of bird eyes is the oil droplets located in front of the visual-pigment-containing outer segments. The droplets vary in colour and are transparent, clear, pale or rather intensely yellow or red owing to various concentrations of carotenoid pigments. Quantitative modelling of the filter characteristics using known carotenoid pigment spectra indicates that the pigments’ absorption spectra are modified by the high concentrations that are present in the yellow and red droplets. The high carotenoid concentrations not only cause strong spectral filtering but also a distinctly increased refractive index at longer wavelengths. The oil droplets therefore act as powerful spherical microlenses, effectively channelling the spectrally filtered light into the photoreceptor's outer segment, possibly thereby compensating for the light loss caused by the spectral filtering. The spectral filtering causes narrow-band photoreceptor spectral sensitivities, which are well suited for spectral discrimination, especially in birds that have feathers coloured by carotenoid pigments. PMID:24395968

The formation of the light-sensing compartment of cone photoreceptors coincides with a transcriptional switch

PubMed Central

Daum, Janine M; Keles, Özkan; Holwerda, Sjoerd JB; Kohler, Hubertus; Rijli, Filippo M

2017-01-01

High-resolution daylight vision is mediated by cone photoreceptors. The molecular program responsible for the formation of their light sensor, the outer segment, is not well understood. We correlated daily changes in ultrastructure and gene expression in postmitotic mouse cones, between birth and eye opening, using serial block-face electron microscopy (EM) and RNA sequencing. Outer segments appeared rapidly at postnatal day six and their appearance coincided with a switch in gene expression. The switch affected over 14% of all expressed genes. Genes that switched off were rich in transcription factors and neurogenic genes. Those that switched on contained genes relevant for cone function. Chromatin rearrangements in enhancer regions occurred before the switch was completed, but not after. We provide a resource comprised of correlated EM, RNAseq, and ATACseq data, showing that the growth of a key compartment of a postmitotic cell involves an extensive switch in gene expression and chromatin accessibility. PMID:29106373

Quantification of common carotid artery and descending aorta vessel wall thickness from MR vessel wall imaging using a fully automated processing pipeline.

PubMed

Gao, Shan; van 't Klooster, Ronald; Brandts, Anne; Roes, Stijntje D; Alizadeh Dehnavi, Reza; de Roos, Albert; Westenberg, Jos J M; van der Geest, Rob J

2017-01-01

To develop and evaluate a method that can fully automatically identify the vessel wall boundaries and quantify the wall thickness for both common carotid artery (CCA) and descending aorta (DAO) from axial magnetic resonance (MR) images. 3T MRI data acquired with T 1 -weighted gradient-echo black-blood imaging sequence from carotid (39 subjects) and aorta (39 subjects) were used to develop and test the algorithm. The vessel wall segmentation was achieved by respectively fitting a 3D cylindrical B-spline surface to the boundaries of lumen and outer wall. The tube-fitting was based on the edge detection performed on the signal intensity (SI) profile along the surface normal. To achieve a fully automated process, Hough Transform (HT) was developed to estimate the lumen centerline and radii for the target vessel. Using the outputs of HT, a tube model for lumen segmentation was initialized and deformed to fit the image data. Finally, lumen segmentation was dilated to initiate the adaptation procedure of outer wall tube. The algorithm was validated by determining: 1) its performance against manual tracing; 2) its interscan reproducibility in quantifying vessel wall thickness (VWT); 3) its capability of detecting VWT difference in hypertensive patients compared with healthy controls. Statistical analysis including Bland-Altman analysis, t-test, and sample size calculation were performed for the purpose of algorithm evaluation. The mean distance between the manual and automatically detected lumen/outer wall contours was 0.00 ± 0.23/0.09 ± 0.21 mm for CCA and 0.12 ± 0.24/0.14 ± 0.35 mm for DAO. No significant difference was observed between the interscan VWT assessment using automated segmentation for both CCA (P = 0.19) and DAO (P = 0.94). Both manual and automated segmentation detected significantly higher carotid (P = 0.016 and P = 0.005) and aortic (P < 0.001 and P = 0.021) wall thickness in the hypertensive patients. A reliable and reproducible pipeline for fully automatic vessel wall quantification was developed and validated on healthy volunteers as well as patients with increased vessel wall thickness. This method holds promise for helping in efficient image interpretation for large-scale cohort studies. 4 J. Magn. Reson. Imaging 2017;45:215-228. © 2016 International Society for Magnetic Resonance in Medicine.

Intra- and intersegmental influences among central pattern generating networks in the walking system of the stick insect.

PubMed

Mantziaris, Charalampos; Bockemühl, Till; Holmes, Philip; Borgmann, Anke; Daun, Silvia; Büschges, Ansgar

2017-10-01

To efficiently move around, animals need to coordinate their limbs. Proper, context-dependent coupling among the neural networks underlying leg movement is necessary for generating intersegmental coordination. In the slow-walking stick insect, local sensory information is very important for shaping coordination. However, central coupling mechanisms among segmental central pattern generators (CPGs) may also contribute to this. Here, we analyzed the interactions between contralateral networks that drive the depressor trochanteris muscle of the legs in both isolated and interconnected deafferented thoracic ganglia of the stick insect on application of pilocarpine, a muscarinic acetylcholine receptor agonist. Our results show that depressor CPG activity is only weakly coupled between all segments. Intrasegmental phase relationships differ between the three isolated ganglia, and they are modified and stabilized when ganglia are interconnected. However, the coordination patterns that emerge do not resemble those observed during walking. Our findings are in line with recent studies and highlight the influence of sensory input on coordination in slowly walking insects. Finally, as a direct interaction between depressor CPG networks and contralateral motoneurons could not be observed, we hypothesize that coupling is based on interactions at the level of CPG interneurons. NEW & NOTEWORTHY Maintaining functional interleg coordination is vitally important as animals locomote through changing environments. The relative importance of central mechanisms vs. sensory feedback in this process is not well understood. We analyzed coordination among the neural networks generating leg movements in stick insect preparations lacking phasic sensory feedback. Under these conditions, the networks governing different legs were only weakly coupled. In stick insect, central connections alone are thus insufficient to produce the leg coordination observed behaviorally. Copyright © 2017 the American Physiological Society.

Transition duct system with metal liners for delivering hot-temperature gases in a combustion turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include a straight path segment (26) and an arcuate connecting segment (36). A respective straight metal liner (92) and an arcuate metal liner (94) may be each inwardly disposed onto a metal outer shell (38) along the straight path segment and the arcuate connecting segment (36) of the exit piece. Structural arrangements are provided to securely attach the respective liners in the presence of substantialmore » flow path pressurization. Cost-effective serviceability of the transition duct systems is realizable since the liners can be readily removed and replaced as needed.« less

Effects of clinical infrared laser on superficial radial nerve conduction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Greathouse, D.G.; Currier, D.P.; Gilmore, R.L.

The purposes of this study were to demonstrate the effects of infrared laser radiation on the sensory nerve conduction of a specified peripheral nerve in man and determine temperature changes in the tissue surrounding the treated nerve. Twenty healthy adults were divided into three groups: control (n = 5); experimental (n = 10), infrared laser radiation at 20 sec/cm2; and experimental (n = 5), infrared laser radiation treatment at 120 sec/cm2. Antidromic sensory nerve conduction studies were performed on the superficial radial nerve of each subject's right forearm. The infrared laser radiation was applied at a fixed intensity for fivemore » 1-cm2 segments. Latency, amplitude, and temperature measurements were recorded pretest; posttest; and posttest intervals of 1, 3, 5, 10, and 15 minutes. An analysis of variance with repeated measures was used to examine the data. No significant change was noted in the distal sensory latency or amplitude of the evoked sensory potential in either experimental or control groups as a result of the applications of the infrared laser radiation treatment. This study demonstrates that infrared laser used at clinically applied intensities does not alter conduction of sensory nerves nor does it elevate the subcutaneous temperature.« less

Preference mapping of dulce de leche commercialized in Brazilian markets.

PubMed

Gaze, L V; Oliveira, B R; Ferrao, L L; Granato, D; Cavalcanti, R N; Conte Júnior, C A; Cruz, A G; Freitas, M Q

2015-03-01

Dulce de leche samples available in the Brazilian market were submitted to sensory profiling by quantitative descriptive analysis and acceptance test, as well sensory evaluation using the just-about-right scale and purchase intent. External preference mapping and the ideal sensory characteristics of dulce de leche were determined. The results were also evaluated by principal component analysis, hierarchical cluster analysis, partial least squares regression, artificial neural networks, and logistic regression. Overall, significant product acceptance was related to intermediate scores of the sensory attributes in the descriptive test, and this trend was observed even after consumer segmentation. The results obtained by sensometric techniques showed that optimizing an ideal dulce de leche from the sensory standpoint is a multidimensional process, with necessary adjustments on the appearance, aroma, taste, and texture attributes of the product for better consumer acceptance and purchase. The optimum dulce de leche was characterized by high scores for the attributes sweet taste, caramel taste, brightness, color, and caramel aroma in accordance with the preference mapping findings. In industrial terms, this means changing the parameters used in the thermal treatment and quantitative changes in the ingredients used in formulations. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Pipe gripper

DOEpatents

Moyers, S.M.

1975-12-16

A device for gripping the exterior surface of a pipe or rod is described which has a plurality of wedges, each having a concave face which engages the outer surface of the pipe and each having a smooth face opposing the concave face. The wedges are seated on and their grooved concave faces are maintained in circular alignment by tapered axial segments of an opening extending through a wedge-seating member. The wedges are allowed to slide across the tapered axial segments so that such a sliding movement acts to vary the diameter of the circular alignment.

The retinal morphology and retinal histochemistry of a twilight fish Corydoras paleatus (J.).

PubMed

Yew, D T; Woo, H H

1976-01-01

1. The retinas of Corydoras paleatus were studied by histology (HE) and histochemistry (PAS and Nucleic acid). 2. Three types of visual cells were observed, namely rod, single cone and twin cone. All of them are PAS positive. 3. The histochemical PAS pattern of these visual cells differs from those species which are not of a twilight habitat. 4. Significant amount of RNA were not detected in the inner segments of visual cells in this species indicating a possible slow renewal of outer segments.

Human locognosic acuity on the arm varies with explicit and implicit manipulations of attention: implications for interpreting elevated tactile acuity on an amputation stump.

PubMed

O'Boyle, D J; Moore, C E; Poliakoff, E; Butterworth, R; Sutton, A; Cody, F W

2001-06-01

In Experiment 1, normal subjects' ability to localize tactile stimuli (locognosia) delivered to the upper arm was significantly higher when they were instructed explicitly to direct their attention selectively to that segment than when they were instructed explicitly to distribute their attention across the whole arm. This elevation of acuity was eliminated when subjects' attentional resources were divided by superimposition of an effortful, secondary task during stimulation. In Experiment 2, in the absence of explicit attentional instruction, subjects' locognosic acuity on one of three arm segments was significantly higher when stimulation of that segment was 2.5 times more probable than that of stimulation of the other two segments. We surmise that the attentional mechanisms responsible for such modulations of locognosic acuity in normal subjects may contribute to the elevated sensory acuity observed on the stumps of amputees.

Stress Transfer Processes during Great Plate Boundary Thrusting Events: A Study from the Andaman and Nicobar Segments

NASA Astrophysics Data System (ADS)

Andrade, V.; Rajendran, K.

2010-12-01

The response of subduction zones to large earthquakes varies along their strike, both during the interseismic and post-seismic periods. The December 26, 2004 earthquake nucleated at 3° N latitude and its rupture propagated northward, along the Andaman-Sumatra subduction zone, terminating at 15°N. Rupture speed was estimated at about 2.0 km per second in the northern part under the Andaman region and 2.5 - 2.7 km per second under southern Nicobar and North Sumatra. We have examined the pre and post-2004 seismicity to understand the stress transfer processes within the subducting plate, in the Andaman (10° - 15° N ) and Nicobar (5° - 10° N) segments. The seismicity pattern in these segments shows distinctive characteristics associated with the outer rise, accretionary prism and the spreading ridge, all of which are relatively better developed in the Andaman segment. The Ninety East ridge and the Sumatra Fault System are significant tectonic features in the Nicobar segment. The pre-2004 seismicity in both these segments conform to the steady-state conditions wherein large earthquakes are fewer and compressive stresses dominate along the plate interface. Among the pre-2004 great earthquakes are the 1881 Nicobar and 1941 Andaman events. The former is considered to be a shallow thrust event that generated a small tsunami. Studies in other subduction zones suggest that large outer-rise tensional events follow great plate boundary breaking earthquakes due to the the up-dip transfer of stresses within the subducting plate. The seismicity of the Andaman segment (1977-2004) concurs with the steady-state stress conditions where earthquakes occur dominantly by thrust faulting. The post-2004 seismicity shows up-dip migration along the plate interface, with dominance of shallow normal faulting, including a few outer rise events and some deeper (> 100 km) strike-slip faulting events within the subducting plate. The September 13, 2002, Mw 6.5 thrust faulting earthquake at Diglipur (depth: 21 km) and the August 10, 2009, Mw 7.5 normal faulting earthquake near Coco Island (depth: 22 km), within the northern terminus of the 2004 rupture are cited as examples of the alternating pre and post earthquake stress conditions. The major pre and post 2004 clusters were associated with the Andaman Spreading Ridge (ASR). In the Nicobar segment, the most recent earthquake on June 12, 2010, Mw 7.5 (focal depth: 35 km) occurred very close to the plate boundary, through left lateral strike-slip faulting. A segment that does not feature any active volcanoes unlike its northern and southern counterparts, this part of the plate boundary has generated several right lateral strike-slip earthquakes, mostly on the Sumatra Fault System. The left-lateral strike-slip faulting associated with the June 12 event on a nearly N-S oriented fault plane consistent with the trend of the Ninety East ridge and the occasional left-lateral earthquakes prior to the 2004 mega-thrust event suggest the involvement of the Ninety East ridge in the subduction process.

Histologic development of the human fovea from midgestation to maturity.

PubMed

Hendrickson, Anita; Possin, Daniel; Vajzovic, Lejla; Toth, Cynthia A

2012-11-01

To describe the histologic development of the human central retina from fetal week (Fwk) 22 to 13 years. Retrospective observational case series. Retinal layers and neuronal substructures were delineated on foveal sections of fixed tissue stained in azure II-methylene blue and on frozen sections immunolabeled for cone, rod, or glial proteins. Postmortem tissue was from 11 eyes at Fwk 20-27; 8 eyes at Fwk 28-37; 6 eyes at postnatal 1 day to 6 weeks; 3 eyes at 9 to 15 months; and 5 eyes at 28 months to 13 years. At Fwk 20-22 the fovea could be identified by the presence of a single layer of cones in the outer nuclear layer. Immunolabeling detected synaptic proteins, cone and rod opsins, and Müller glial processes separating the photoreceptors. The foveal pit appeared at Fwk 25, involving progressive peripheral displacement of ganglion cell, inner plexiform, and inner nuclear layers. The pit became wider and shallower after birth, and appeared mature by 15 months. Between Fwk 25 and Fwk 38, all photoreceptors developed more distinct inner and outer segments, but these were longer on peripheral than foveal cones. After birth the foveal outer nuclear layer became much thicker as cone packing occurred. Cone packing and neuronal migration during pit formation combined to form long central photoreceptor axons, which changed the outer plexiform layer from a thin sheet of synaptic pedicles into the thickest layer in the central retina by 15 months. Foveal inner and outer segment length matched peripheral cones by 15 months and was 4 times longer by 13 years. These data are necessary to understand the marked changes in human retina from late gestation to early adulthood. They provide qualitative and quantitative morphologic information required to interpret the changes in hyper- and hyporeflexive bands in pediatric spectral-domain optical coherence tomography images at the same ages. Copyright © 2012 Elsevier Inc. All rights reserved.

Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo

PubMed Central

Berkowitz, Bruce A.; Gorgis, Jawan; Patel, Ankit; Baameur, Faiza; Gurevich, Vsevolod V.; Craft, Cheryl M.; Kefalov, Vladimir J.; Roberts, Robin

2015-01-01

Rod tetrameric arrestin 1 (tet-ARR1), stored in the outer nuclear layer/inner segments in the dark, modulates photoreceptor synaptic activity; light exposure stimulates a reduction via translocation to the outer segments for terminating G-protein coupled phototransduction signaling. Here, we test the hypothesis that intraretinal spin-lattice relaxation rate in the rotating frame (1/T1ρ), an endogenous MRI contrast mechanism, has high potential for evaluating rod tet-ARR1 and its reduction via translocation. Dark- and light-exposed mice (null for the ARR1 gene, overexpressing ARR1, diabetic, or wild type with or without treatment with Mn2+, a calcium channel probe) were studied using 1/T1ρ MRI. Immunohistochemistry and single-cell recordings of the retinas were also performed. In wild-type mice with or without treatment with Mn2+, 1/T1ρ of avascular outer retina (64% to 72% depth) was significantly (P < 0.05) greater in the dark than in the light; a significant (P < 0.05) but opposite pattern was noted in the inner retina (<50% depth). Light-evoked outer retina Δ1/T1ρ was absent in ARR1-null mice and supernormal in overexpressing mice. In diabetic mice, the outer retinal Δ1/T1ρ pattern suggested normal dark-to-light tet-ARR1 translocation and chromophore content, conclusions confirmed ex vivo. Light-stimulated Δ1/T1ρ in inner retina was linked to changes in blood volume. Our data support 1/T1ρ MRI for noninvasively assessing rod tet-ARR1 and its reduction via protein translocation, which can be combined with other metrics of retinal function in vivo.—Berkowitz, B. A., Gorgis, J., Patel, A., Baameur, F., Gurevich, V. V., Craft, C. M., Kefalov, V. J., Roberts, R. Development of an MRI biomarker sensitive to tetrameric visual arrestin 1 and its reduction via light-evoked translocation in vivo. PMID:25351983

Automatic segmentation of equine larynx for diagnosis of laryngeal hemiplegia

NASA Astrophysics Data System (ADS)

Salehin, Md. Musfequs; Zheng, Lihong; Gao, Junbin

2013-10-01

This paper presents an automatic segmentation method for delineation of the clinically significant contours of the equine larynx from an endoscopic image. These contours are used to diagnose the most common disease of horse larynx laryngeal hemiplegia. In this study, hierarchal structured contour map is obtained by the state-of-the-art segmentation algorithm, gPb-OWT-UCM. The conic-shaped outer boundary of equine larynx is extracted based on Pascal's theorem. Lastly, Hough Transformation method is applied to detect lines related to the edges of vocal folds. The experimental results show that the proposed approach has better performance in extracting the targeted contours of equine larynx than the results of using only the gPb-OWT-UCM method.

THE ORGANOPHOSPHOROUS INSECTICIDE FENTHION DOES NOT AFFECT PHAGOCYTOSIS OF ROD OUTER SEGMENTS BY RETINAL PIGMENT EPITHELIUM CELLS IN CULTURE.

EPA Science Inventory

:
Exposure to the organophosphorous insecticide fenthion has been associated with retinal degeneration in occupational studies. It has also been associated with pigmentary changes of the retina. Because retinal degeneration and pigmentary changes may be due to dysfunction of t...

Structural and Functional Changes Associated with Normal and Abnormal Fundus Autofluorescence in Patients with Retinitis Pigmentosa

PubMed Central

Greenstein, Vivienne C.; Duncker, Tobias; Holopigian, Karen; Carr, Ronald E.; Greenberg, Jonathan; Tsang, Stephen H.; Hood, Donald C.

2013-01-01

Purpose To analyze the structure and visual function of regions bordering the hyperautofluorescent ring/arcs in retinitis pigmentosa (RP). Methods Twenty -one RP patients (21 eyes) with rings/arcs and 21 normals (21 eyes) were studied. Visual sensitivity in the central 10° was measured with microperimetry. Retinal structure was evaluated with spectral domain optical coherence tomography (SD-OCT). The distance from the fovea to disruption/loss of the inner outer segment (IS/OS) junction and thicknesses of the total receptor plus retinal pigment epithelial (RPE) complex (R+), and outer segment plus RPE complex (OS+) layers were measured. Results were compared to measurements of the distance from the fovea to the inner and outer borders of the ring/arc seen on fundus autofluorescence (FAF). Results Disruption/loss of the IS/OS junction occurred closer to the inner border of the ring/arc and it was closer to the fovea in 8 eyes. For 19 eyes, OS+ and R+ thicknesses were significantly decreased at locations closer to the fovea than the appearance of the inner border of hyperautofluorescence. Mean visual sensitivity was decreased inside, across and outside the ring/arc by 3.5 ± 3.8, 8.9 ± 4.8 and 17.0±2.4 dB respectively. Conclusions Structural and functional changes can occur inside the hyperfluorescent ring/arc in RP. PMID:21909055

Evaluation of the Lower Punctum Parameters and Morphology Using Spectral Domain Anterior Segment Optical Coherence Tomography

PubMed Central

Allam, Riham S. H. M.; Ahmed, Rania A.

2015-01-01

Purpose. To study features of the lower punctum in normal subjects using spectral domain anterior segment optical coherence tomography (SD AS-OCT). Methods. Observational cross-sectional study that included 147 punctae (76 subjects). Punctae were evaluated clinically for appearance, position, and size. AS-OCT was used to evaluate the punctal shape, contents, and junction with the vertical canaliculus. Inner and outer diameters as well as depth were measured. Results. 24 males and 52 females (mean age 44 ± 14.35 y) were included. Lower punctum was perceived by OCT to be an area with an outer diameter (mean 412.16 ± 163 μm), inner diameter (mean 233.67 ± 138.73 μm), and depth (mean 251.7 ± 126.58 μm). The OCT measured outer punctum diameter was significantly less than that measured clinically (P: 0.000). Seven major shapes were identified. The junction with the vertical canaliculus was detectable in 44%. Fluid was detected in 34%, one of which had an air bubble; however, 63% of punctae showed no contents and 4% had debris. Conclusions. AS-OCT can be a useful tool in understanding the anatomy of the punctum and distal lacrimal system as well as tear drainage physiology. Measuring the punctum size may play a role in plugs fitting. PMID:26090219

The role of sensory augmentation for people with vestibular deficits: Real-time balance aid and/or rehabilitation device?

PubMed

Sienko, K H; Whitney, S L; Carender, W J; Wall, C

2017-01-01

This narrative review highlights findings from the sensory augmentation field for people with vestibular deficits and addresses the outstanding questions that are critical to the translation of this technology into clinical and/or personal use. Prior research has demonstrated that the real-time use of visual, vibrotactile, auditory, and multimodal sensory augmentation technologies can improve balance during static and dynamic stance tasks within a laboratory setting. However, its application in improving gait requires additional investigation, as does its efficacy as a rehabilitation device for people with vestibular deficits. In some locomotor studies involving sensory augmentation, gait velocity decreased and secondary task performance worsened, and subjects negatively altered their segmental control strategies when cues were provided following short training sessions. A further question is whether the retention and/or carry-over effects of training with a sensory augmentation technology exceed the retention and/or carry-over effects of training alone, thereby supporting its use as a rehabilitation device. Preliminary results suggest that there are short-term improvements in balance performance following a small number of training sessions with a sensory augmentation device. Long-term clinical and home-based controlled training studies are needed. It is hypothesized that sensory augmentation provides people with vestibular deficits with additional sensory input to promote central compensation during a specific exercise/activity; however, research is needed to substantiate this theory. Major obstacles standing in the way of its use for these critical applications include determining exercise/activity specific feedback parameters and dosage strategies. This paper summarizes the reported findings that support sensory augmentation as a balance aid and rehabilitation device, but does not critically examine efficacy or the quality of the research methods used in the reviewed studies.

History, heresy and radiology in scientific discovery.

PubMed

McCredie, J

2009-10-01

Nowadays, most drugs reach the market after research has established their pharmacology, safety and efficacy. That was not always the case 50 years ago. Thalidomide was used before its target cell or mode of action were known. Commencing with the thalidomide catastrophe--an epidemic of gross birth defects (1958-1962)--thalidomide's origins are revisited to show how this drug came to be made and sold in the 1950s. Thalidomide intersected with Australian radiology in the 1970s. The site and mode of action of the drug was deduced from X-rays of thalidomide-induced bone defects, which have classical radiological signs of sensory neuropathic osteoarthropathy. The longitudinal reduction deformities follow the distribution of segmental sensory innervation of the limb skeleton, indicating neural crest as the target organ. Injury to one level of neural crest halts normal neurotrophism and deletes the dependent segment--a previously unrecognised embryonic mechanism that explains most non-genetic birth defects. The final common pathway is neural crest injury and failure of normal neurotrophism to result in longitudinal reduction deformities, for example, phocomelia.

Mechanosensilla in the adult abdomen of Drosophila: engrailed and slit help to corral the peripheral sensory axons into segmental bundles.

PubMed

Fabre, Caroline C G; Casal, José; Lawrence, Peter A

2010-09-01

The abdomen of adult Drosophila bears mechanosensory bristles with axons that connect directly to the CNS, each hemisegment contributing a separate nerve bundle. Here, we alter the amount of Engrailed protein and manipulate the Hedgehog signalling pathway in clones of cells to study their effects on nerve pathfinding within the peripheral nervous system. We find that high levels of Engrailed make the epidermal cells inhospitable to bristle neurons; sensory axons that are too near these cells are either deflected or fail to extend properly or at all. We then searched for the engrailed-dependent agent responsible for these repellent properties. We found slit to be expressed in the P compartment and, using genetic mosaics, present evidence that Slit is the responsible molecule. Blocking the activity of the three Robo genes (putative receptors for Slit) with RNAi supported this hypothesis. We conclude that, during normal development, gradients of Slit protein repel axons away from compartment boundaries - in consequence, the bristles from each segment send their nerves to the CNS in separated sets.

Influence of Japanese consumer gender and age on sensory attributes and preference (a case study on deep-fried peanuts).

PubMed

Miyagi, Atsushi

2017-09-01

Detailed exploration of sensory perception as well as preference across gender and age for a certain food is very useful for developing a vendible food commodity related to physiological and psychological motivation for food preference. Sensory tests including color, sweetness, bitterness, fried peanut aroma, textural preference and overall liking of deep-fried peanuts with varying frying time (2, 4, 6, 9, 12 and 15 min) at 150 °C were carried out using 417 healthy Japanese consumers. To determine the influence of gender and age on sensory evaluation, systematic statistical analysis including one-way analysis of variance, polynomial regression analysis and multiple regression analysis was conducted using the collected data. The results indicated that females were more sensitive to bitterness than males. This may affect sensory preference; female subjects favored peanuts prepared with a shorter frying time more than male subjects did. With advancing age, textural preference played a more important role in overall preference. Older subjects liked deeper-fried peanuts, which are more brittle, more than younger subjects did. In the present study, systematic statistical analysis based on collected sensory evaluation data using deep-fried peanuts was conducted and the tendency of sensory perception and preference across gender and age was clarified. These results may be useful for engineering optimal strategies to target specific segments to gain greater acceptance in the market. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

A new fractional order derivative based active contour model for colon wall segmentation

NASA Astrophysics Data System (ADS)

Chen, Bo; Li, Lihong C.; Wang, Huafeng; Wei, Xinzhou; Huang, Shan; Chen, Wensheng; Liang, Zhengrong

2018-02-01

Segmentation of colon wall plays an important role in advancing computed tomographic colonography (CTC) toward a screening modality. Due to the low contrast of CT attenuation around colon wall, accurate segmentation of the boundary of both inner and outer wall is very challenging. In this paper, based on the geodesic active contour model, we develop a new model for colon wall segmentation. First, tagged materials in CTC images were automatically removed via a partial volume (PV) based electronic colon cleansing (ECC) strategy. We then present a new fractional order derivative based active contour model to segment the volumetric colon wall from the cleansed CTC images. In this model, the regionbased Chan-Vese model is incorporated as an energy term to the whole model so that not only edge/gradient information but also region/volume information is taken into account in the segmentation process. Furthermore, a fractional order differentiation derivative energy term is also developed in the new model to preserve the low frequency information and improve the noise immunity of the new segmentation model. The proposed colon wall segmentation approach was validated on 16 patient CTC scans. Experimental results indicate that the present scheme is very promising towards automatically segmenting colon wall, thus facilitating computer aided detection of initial colonic polyp candidates via CTC.

Compensating Faraday Depolarization by Magnetic Helicity in the Solar Corona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brandenburg, Axel; Ashurova, Mohira B.; Jabbari, Sarah, E-mail: brandenb@nordita.org

A turbulent dynamo in spherical geometry with an outer corona is simulated to study the sign of magnetic helicity in the outer parts. In agreement with earlier studies, the sign in the outer corona is found to be opposite to that inside the dynamo. Line-of-sight observations of polarized emission are synthesized to explore the feasibility of using the local reduction of Faraday depolarization to infer the sign of helicity of magnetic fields in the solar corona. This approach was previously identified as an observational diagnostic in the context of galactic magnetic fields. Based on our simulations, we show that thismore » method can be successful in the solar context if sufficient statistics are gathered by using averages over ring segments in the corona separately for the regions north and south of the solar equator.« less

3D Segmentation of Maxilla in Cone-beam Computed Tomography Imaging Using Base Invariant Wavelet Active Shape Model on Customized Two-manifold Topology

PubMed Central

Chang, Yu-Bing; Xia, James J.; Yuan, Peng; Kuo, Tai-Hong; Xiong, Zixiang; Gateno, Jaime; Zhou, Xiaobo

2013-01-01

Recent advances in cone-beam computed tomography (CBCT) have rapidly enabled widepsread applications of dentomaxillofacial imaging and orthodontic practices in the past decades due to its low radiation dose, high spatial resolution, and accessibility. However, low contrast resolution in CBCT image has become its major limitation in building skull models. Intensive hand-segmentation is usually required to reconstruct the skull models. One of the regions affected by this limitation the most is the thin bone images. This paper presents a novel segmentation approach based on wavelet density model (WDM) for a particular interest in the outer surface of anterior wall of maxilla. Nineteen CBCT datasets are used to conduct two experiments. This mode-based segmentation approach is validated and compared with three different segmentation approaches. The results show that the performance of this model-based segmentation approach is better than those of the other approaches. It can achieve 0.25 ± 0.2mm of surface error from ground truth of bone surface. PMID:23694914

Biological effects of blocking blue and other visible light on the mouse retina.

PubMed

Narimatsu, Toshio; Ozawa, Yoko; Miyake, Seiji; Kubota, Shunsuke; Yuki, Kenya; Nagai, Norihiro; Tsubota, Kazuo

2014-08-01

To elucidate the biological effects of blocking fluorescent light on the retina using specific blocking materials. Seven- to 8-week-old BALB/c mice were divided into three groups and placed in one of the three boxes: one blocked ultraviolet and violet wavelengths of light (violet blockade), one blocked ultraviolet, violet, blue and some other visible wavelengths (blue-plus blockade), and one allowed most visible light to pass through (control). They were then exposed to a white fluorescent lamp for 1 h at 5.65E-05 mW/cm(2) /s. After treatment, the electroretinogram, retinal outer nuclear layer thickness and retinal outer segment length were measured. In addition, retinal apoptotic cells were quantified by TdT-mediated dUTP nick-end labelling assay and c-Fos messenger RNA, and protein levels were measured by real-time reverse-transcription polymerase chain reaction and immunoblot analyses, respectively. The blue-plus blockade group retained a significantly better electroretinogram response following light exposure than the control or violet blockade groups. The blue-plus blockade group also exhibited greater outer nuclear layer thickness and greater outer-segment length, and fewer apoptotic cells after light exposure than the other groups. The c-Fos messenger RNA and protein levels were substantially reduced in the blue-plus blockade group and reduced to a lesser extent in the violet blockade group. The blockade of blue plus additional visible wavelengths of light was most effective in protecting the retina from light-induced damage. The blockade of violet light alone was also effective in reducing intracellular molecular responses, but these effects were not sufficient for attenuating retinal degeneration. © 2013 Royal Australian and New Zealand College of Ophthalmologists.

Characteristics of intraretinal deposits in acute central serous chorioretinopathy.

PubMed

Plateroti, Andrea M; Witmer, Matthew T; Kiss, Szilárd; D'Amico, Donald J

2014-01-01

To describe the temporal and spatial characteristics of intraretinal deposits in patients with acute central serous chorioretinopathy (CSC) using spectral domain optical coherence tomography (OCT). We retrospectively reviewed the medical records of all patients that presented with acute CSC to Weill Cornell Medical College from January 2012 to May 2013. Acute CSC was defined as a diagnosis of CSC within 4 months of the onset of symptoms. Only one eye per patient was included in the study. Each patient was imaged with spectral domain OCT at the initial office visit. The decision to reimage these patients was made by the treating physician. A total of 25 patients (25 eyes; 17 men and eight nonpregnant women) were included in this review. Seven of 25 patients (28%) demonstrated intraretinal deposits within the outer plexiform layer during the initial OCT, with deposits appearing as early as the same day as the onset of symptoms. A total of 25 of 25 patients (100%) demonstrated intraretinal deposits in the outer nuclear layer upon initial (76%) or follow-up OCT, as early as 2 days after the onset of symptoms. A total of 24 of 25 patients (96%) demonstrated deposits in the external limiting membrane upon a follow-up OCT, as early as 7 days from symptoms appearing. A total of 24 of 25 patients (96%) developed intraretinal deposits in the inner segment/outer segment layer upon follow-up OCT, appearing as early as 14 days after symptom onset. At the time of resolution of subretinal fluid, 20 of 25 patients (80%) demonstrated intraretinal deposits. Intraretinal deposits are present in the outer retinal layers in patients with acute CSC, with the deposits appearing progressively deeper within the retina as the condition evolves. Upon resolution of subretinal fluid, the deposits slowly resolve.

Architecture of the human renal inner medulla and functional implications.

PubMed

Wei, Guojun; Rosen, Seymour; Dantzler, William H; Pannabecker, Thomas L

2015-10-01

The architecture of the inner stripe of the outer medulla of the human kidney has long been known to exhibit distinctive configurations; however, inner medullary architecture remains poorly defined. Using immunohistochemistry with segment-specific antibodies for membrane fluid and solute transporters and other proteins, we identified a number of distinctive functional features of human inner medulla. In the outer inner medulla, aquaporin-1 (AQP1)-positive long-loop descending thin limbs (DTLs) lie alongside descending and ascending vasa recta (DVR, AVR) within vascular bundles. These vascular bundles are continuations of outer medullary vascular bundles. Bundles containing DTLs and vasa recta lie at the margins of coalescing collecting duct (CD) clusters, thereby forming two regions, the vascular bundle region and the CD cluster region. Although AQP1 and urea transporter UT-B are abundantly expressed in long-loop DTLs and DVR, respectively, their expression declines with depth below the outer medulla. Transcellular water and urea fluxes likely decline in these segments at progressively deeper levels. Smooth muscle myosin heavy chain protein is also expressed in DVR of the inner stripe and the upper inner medulla, but is sparsely expressed at deeper inner medullary levels. In rodent inner medulla, fenestrated capillaries abut CDs along their entire length, paralleling ascending thin limbs (ATLs), forming distinct compartments (interstitial nodal spaces; INSs); however, in humans this architecture rarely occurs. Thus INSs are relatively infrequent in the human inner medulla, unlike in the rodent where they are abundant. UT-B is expressed within the papillary epithelium of the lower inner medulla, indicating a transcellular pathway for urea across this epithelium. Copyright © 2015 the American Physiological Society.

Scanning electron microscopy of antennal sensory organs of the cattle grub, Hypoderma lineatum (Diptera: Oestridae).

PubMed

Li, X Y; Liu, X H; Ge, Y Q; Zhang, D

2015-10-01

Hypoderma lineatum (Villers, 1789) (Diptera: Oestridae) is a hypodermosis fly that has resulted in great economic losses worldwide. The antennae of cattle grub males and females were examined through stereoscopic microscopy and scanning electron microscopy to reveal the general morphology, combined with distribution, type, size, and ultrastructure of the antennal sensilla. All of the three antennal segments (antennal scape, pedicel, and funiculus) possess microtrichiae on their surface. Mechanoreceptors only exist on the antennal scape and pedicel. The antennal funiculus presents four types of antennal sensilla: trichoid, basiconic, coeloconic, and clavate sensilla. Three distinctive characters of H. lineatum are obvious: (1) the relatively slender, flexible, and equal-height mechanoreceptors; (2) the enlarged antennal pedicel, and numerous antennal sensory pits and pit sensilla on the antennal funiculus; and (3) all types of antennal sensilla clustered in sensory pits, respectively. Additionally, the enlarged antennal pedicel and abundant sensory pits and pit sensilla might facilitate odor detection, enhance olfactory sensitivity and accuracy, and also protect the fragile antennal sensilla from mechanical irritation or damage.

Two passive mechanical conditions modulate power generation by the outer hair cells

PubMed Central

Gracewski, Sheryl M.

2017-01-01

In the mammalian cochlea, small vibrations of the sensory epithelium are amplified due to active electro-mechanical feedback of the outer hair cells. The level of amplification is greater in the base than in the apex of the cochlea. Theoretical studies have used longitudinally varying active feedback properties to reproduce the location-dependent amplification. The active feedback force has been considered to be proportional to the basilar membrane displacement or velocity. An underlying assumption was that organ of Corti mechanics are governed by rigid body kinematics. However, recent progress in vibration measurement techniques reveals that organ of Corti mechanics are too complicated to be fully represented with rigid body kinematics. In this study, two components of the active feedback are considered explicitly—organ of Corti mechanics, and outer hair cell electro-mechanics. Physiological properties for the outer hair cells were incorporated, such as the active force gain, mechano-transduction properties, and membrane RC time constant. Instead of a kinematical model, a fully deformable 3D finite element model was used. We show that the organ of Corti mechanics dictate the longitudinal trend of cochlear amplification. Specifically, our results suggest that two mechanical conditions are responsible for location-dependent cochlear amplification. First, the phase of the outer hair cell’s somatic force with respect to its elongation rate varies along the cochlear length. Second, the local stiffness of the organ of Corti complex felt by individual outer hair cells varies along the cochlear length. We describe how these two mechanical conditions result in greater amplification toward the base of the cochlea. PMID:28880884

The signaling helix: a common functional theme in diverse signaling proteins

PubMed Central

Anantharaman, Vivek; Balaji, S; Aravind, L

2006-01-01

Background The mechanism by which the signals are transmitted between receptor and effector domains in multi-domain signaling proteins is poorly understood. Results Using sensitive sequence analysis methods we identify a conserved helical segment of around 40 residues in a wide range of signaling proteins, including numerous sensor histidine kinases such as Sln1p, and receptor guanylyl cyclases such as the atrial natriuretic peptide receptor and nitric oxide receptors. We term this helical segment the signaling (S)-helix and present evidence that it forms a novel parallel coiled-coil element, distinct from previously known helical segments in signaling proteins, such as the Dimerization-Histidine phosphotransfer module of histidine kinases, the intra-cellular domains of the chemotaxis receptors, inter-GAF domain helical linkers and the α-helical HAMP module. Analysis of domain architectures allowed us to reconstruct the domain-neighborhood graph for the S-helix, which showed that the S-helix almost always occurs between two signaling domains. Several striking patterns in the domain neighborhood of the S-helix also became evident from the graph. It most often separates diverse N-terminal sensory domains from various C-terminal catalytic signaling domains such as histidine kinases, cNMP cyclase, PP2C phosphatases, NtrC-like AAA+ ATPases and diguanylate cyclases. It might also occur between two sensory domains such as PAS domains and occasionally between a DNA-binding HTH domain and a sensory domain. The sequence conservation pattern of the S-helix revealed the presence of a unique constellation of polar residues in the dimer-interface positions within the central heptad of the coiled-coil formed by the S-helix. Conclusion Combining these observations with previously reported mutagenesis studies on different S-helix-containing proteins we suggest that it functions as a switch that prevents constitutive activation of linked downstream signaling domains. However, upon occurrence of specific conformational changes due to binding of ligand or other sensory inputs in a linked upstream domain it transmits the signal to the downstream domain. Thus, the S-helix represents one of the most prevalent functional themes involved in the flow of signals between modules in diverse prokaryote-type multi-domain signaling proteins. Reviewers This article was reviewed by Frank Eisenhaber, Arcady Mushegian and Sandor Pongor. PMID:16953892

Sensory characterization of the astringency of commercial Uruguayan Tannat wines.

PubMed

Vidal, Leticia; Antúnez, Lucía; Giménez, Ana; Medina, Karina; Boido, Eduardo; Ares, Gastón

2017-12-01

Astringency is one of the most important characteristics that define the quality of red wine, and is of particular relevance for Tannat, Uruguayan emblematic red wine variety. Astringency is a time-dependant and complex sensory characteristic, related to several sensations, or sub-qualities, that can be simultaneously perceived. The aim of the present study was to obtain a sensory characterization of the astringency of commercial Uruguayan Tannat wines. Forty samples with different characteristics in terms of vintage, price segment and aging in oak barrels were assessed by a panel of 9 trained assessors. Total astringency intensity was evaluated using time-intensity (TI), while astringency sub-qualities were described using a check-all-that-apply (CATA) question composed of sixteen terms. TI and the CATA question provided different information on the astringency of Tannat wines. Regarding global astringency, samples mainly differed in intensity-related parameters rather than in the development of astringency over time, although the variability was moderate. A wide range of sub-qualities, from silky and velvety to harsh and aggressive were used to describe the astringency of the evaluated wines. Four groups of samples with different astringency characteristics were identified, but this sorting was not related to vintage, price segment or aging in oak barrels. Further research is necessary to better understand how astringency characteristics are influenced by production variables, and to understand their relationship to consumers' and experts' perceived quality of Tannat wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

The skin: The many functions of fish integument

USGS Publications Warehouse

Elliott, Diane G.; Farrell, Anthony P.

2011-01-01

The integument or skin is the envelope that not only separates and protects a fish from its environment, but also provides the means through which most contacts with the outer world are made. It is a large organ and is continuous with the linings of all body openings, and also covers the fins. Fish integument is a multifunctional organ, and its components may serve important roles in protection, communication, sensory perception, locomotion, respiration, ion regulation, excretion, and thermal regulation.

Motility of vestibular hair cells in the chick.

PubMed

Ogata, Y; Sekitani, T

1993-01-01

Recent studies of the outer hair cells in cochlea have demonstrated active motilities. However, very little study has been done on the vestibular hair cells (VHCs). The present study shows the motile response of the VHCs induced by application of Ca2+/ATP promoting contraction. Reversible cell shape changes could be shown in 10 of 16 isolated type I hair cells and 9 of 15 isolated type II hair cells by applying the contraction solution. Furthermore, the sensory hair bundles in the utricular epithelium pivoted around the base and stood perpendicularly to the apical borderline of the epithelium in response to the application of the same solution. It is suggested that the contraction of the isolated VHCs may be transferred to tension which causes the sensory hair bundles to restrict their motion in normal tissue, instead of changing the cell shape.

Bicarbonate Modulates Photoreceptor Guanylate Cyclase (ROS-GC) Catalytic Activity*

PubMed Central

Duda, Teresa; Wen, Xiao-Hong; Isayama, Tomoki; Sharma, Rameshwar K.; Makino, Clint L.

2015-01-01

By generating the second messenger cGMP in retinal rods and cones, ROS-GC plays a central role in visual transduction. Guanylate cyclase-activating proteins (GCAPs) link cGMP synthesis to the light-induced fall in [Ca2+]i to help set absolute sensitivity and assure prompt recovery of the response to light. The present report discloses a surprising feature of this system: ROS-GC is a sensor of bicarbonate. Recombinant ROS-GCs synthesized cGMP from GTP at faster rates in the presence of bicarbonate with an ED50 of 27 mm for ROS-GC1 and 39 mm for ROS-GC2. The effect required neither Ca2+ nor use of the GCAPs domains; however, stimulation of ROS-GC1 was more powerful in the presence of GCAP1 or GCAP2 at low [Ca2+]. When applied to retinal photoreceptors, bicarbonate enhanced the circulating current, decreased sensitivity to flashes, and accelerated flash response kinetics. Bicarbonate was effective when applied either to the outer or inner segment of red-sensitive cones. In contrast, bicarbonate exerted an effect when applied to the inner segment of rods but had little efficacy when applied to the outer segment. The findings define a new regulatory mechanism of the ROS-GC system that affects visual transduction and is likely to affect the course of retinal diseases caused by cGMP toxicity. PMID:25767116

Physiological and Microfluorometric Studies of Reduction and Clearance of Retinal in Bleached Rod Photoreceptors

PubMed Central

Tsina, Efthymia; Chen, Chunhe; Koutalos, Yiannis; Ala-Laurila, Petri; Tsacopoulos, Marco; Wiggert, Barbara; Crouch, Rosalie K.; Cornwall, M. Carter

2004-01-01

The visual cycle comprises a sequence of reactions that regenerate the visual pigment in photoreceptors during dark adaptation, starting with the reduction of all-trans retinal to all-trans retinol and its clearance from photoreceptors. We have followed the reduction of retinal and clearance of retinol within bleached outer segments of red rods isolated from salamander retina by measuring its intrinsic fluorescence. Following exposure to a bright light (bleach), increasing fluorescence intensity was observed to propagate along the outer segments in a direction from the proximal region adjacent to the inner segment toward the distal tip. Peak retinol fluorescence was achieved after ∼30 min, after which it declined very slowly. Clearance of retinol fluorescence is considerably accelerated by the presence of the exogenous lipophilic substances IRBP (interphotoreceptor retinoid binding protein) and serum albumin. We have used simultaneous fluorometric and electrophysiological measurements to compare the rate of reduction of all-trans retinal to all-trans retinol to the rate of recovery of flash response amplitude in these cells in the presence and absence of IRBP. We find that flash response recovery in rods is modestly accelerated in the presence of extracellular IRBP. These results suggest such substances may participate in the clearance of retinoids from rod photoreceptors, and that this clearance, at least in rods, may facilitate dark adaptation by accelerating the clearance of photoproducts of bleaching. PMID:15452202

Airfoil nozzle and shroud assembly

DOEpatents

Shaffer, James E.; Norton, Paul F.

1997-01-01

An airfoil and nozzle assembly including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached.

Autofluorescence Imaging and Spectral-Domain Optical Coherence Tomography in Incomplete Congenital Stationary Night Blindness and Comparison with Retinitis Pigmentosa

PubMed Central

CHEN, ROYCE W. S.; GREENBERG, JONATHAN P.; LAZOW, MARGOT A.; RAMACHANDRAN, RITHU; LIMA, LUIZ H.; HWANG, JOHN C.; SCHUBERT, CARL; BRAUNSTEIN, ALEXANDRA; ALLIKMETS, RANDO; TSANG, STEPHEN H.

2015-01-01

PURPOSE To test the hypothesis that the evaluation of retinal structure can have diagnostic value in differentiating between incomplete congenital stationary night blindness (CSNB2) and retinitis pigmentosa (RP). To compare retinal thickness differences between patients with CSNB2 and myopic controls. DESIGN Prospective cross-sectional study. METHODS Ten eyes of 5 patients diagnosed with CSNB2 (4 X-linked recessive, 1 autosomal recessive) and 6 eyes of 3 patients with RP (2 autosomal dominant, 1 autosomal recessive) were evaluated with spectral-domain optical coherence tomography (SD OCT) and fundus autofluorescence (FAF). Diagnoses of CSNB2 and RP were confirmed by full-field electroretinography (ERG). Manual segmentation of retinal layers, aided by a computer program, was performed by 2 professional segmenters on SD OCT images of all CSNB2 patients and 4 age-similar, normal myopic controls. Seven patients were screened for mutations with congenital stationary night blindness and RP genotyping arrays. RESULTS Patients with CSNB2 had specific findings on SD OCT and FAF that were distinct from those found in RP. CSNB2 patients showed qualitatively normal SD OCT results with preserved photoreceptor inner segment/outer segment junction, whereas this junction was lost in RP patients. In addition, CSNB2 patients had normal FAF images, whereas patients with RP demonstrated a ring of increased autofluorescence around the macula. On SD OCT segmentation, the inner and outer retinal layers of both X-linked recessive and autosomal recessive CSNB2 patients were thinner compared with those of normal myopic controls, with means generally outside of normal 95% confidence intervals. The only layers that demonstrated similar thickness between CSNB2 patients and the controls were the retinal nerve fiber layer and, temporal to the fovea, the combined outer segment layer and retinal pigment epithelium. A proband and his 2 affected brothers from a family segregating X-linked recessive CSNB2 had a mutation, p.R614X, in the gene encoding calcium channel, α 1F subunit. CONCLUSIONS CSNB2 patients (X-linked recessive and autosomal recessive) had significantly thinner retinas than myopic controls. However, they demonstrated qualitatively normal SD OCT and FAF images, and therefore can be differentiated from RP patients with these techniques. Although ERG testing remains the gold standard for the diagnosis of these conditions, FAF and SD OCT systems are more widely available to community ophthalmologists, offer shorter acquisition times, and, unlike ERG, can be performed on the same day as the initial clinic visit. Therefore, as a supplement to ERG and genetic testing, we advocate the use of FAF and SD OCT in the examination of patients with CSNB2 and RP. PMID:21920492

Radiant energy collector

DOEpatents

McIntire, William R.

1983-01-01

A cylindrical radiant energy collector is provided which includes a reflector spaced apart from an energy absorber. The reflector is of a particular shape which ideally eliminates gap losses. The reflector includes a plurality of adjacent facets of V shaped segments sloped so as to reflect all energy entering between said absorber and said reflector onto said absorber. The outer arms of each facet are sloped to reflect one type of extremal ray in a line substantially tangent to the lowermost extremity of the energy absorber. The inner arms of the facets are sloped to reflect onto the absorber all rays either falling directly thereon or as a result of reflection from an outer arm.

16 CFR 305.3 - Description of covered products.

Code of Federal Regulations, 2011 CFR

2011-01-01

... operation. Some models may require user intervention to initiate these different segments of the cycle after... inner reflective coating on the outer bulb to direct the light, an R, PAR, or similar bulb shapes... bulb to direct the light, an R, PAR, ER, BR, BPAR, or similar bulb shapes with E26 medium screw bases...

Magnetic Field Analysis of Lorentz Motors Using a Novel Segmented Magnetic Equivalent Circuit Method

PubMed Central

Qian, Junbing; Chen, Xuedong; Chen, Han; Zeng, Lizhan; Li, Xiaoqing

2013-01-01

A simple and accurate method based on the magnetic equivalent circuit (MEC) model is proposed in this paper to predict magnetic flux density (MFD) distribution of the air-gap in a Lorentz motor (LM). In conventional MEC methods, the permanent magnet (PM) is treated as one common source and all branches of MEC are coupled together to become a MEC network. In our proposed method, every PM flux source is divided into three sub-sections (the outer, the middle and the inner). Thus, the MEC of LM is divided correspondingly into three independent sub-loops. As the size of the middle sub-MEC is small enough, it can be treated as an ideal MEC and solved accurately. Combining with decoupled analysis of outer and inner MECs, MFD distribution in the air-gap can be approximated by a quadratic curve, and the complex calculation of reluctances in MECs can be avoided. The segmented magnetic equivalent circuit (SMEC) method is used to analyze a LM, and its effectiveness is demonstrated by comparison with FEA, conventional MEC and experimental results. PMID:23358368

Uncoupling phototoxicity-elicited neural dysmorphology and death by insidious function and selective impairment of Ran-binding protein 2 (Ranbp2).

PubMed

Cho, Kyoung-in; Haney, Victoria; Yoon, Dosuk; Hao, Yin; Ferreira, Paulo A

2015-12-21

Morphological disintegration of neurons is coupled invariably to neural death. In particular, disruption of outer segments of photoreceptor neurons triggers photoreceptor death regardless of the pathological stressors. We show that Ranbp2(-/-)::Tg-Ranbp2(CLDm-HA) mice with mutations in SUMO-binding motif (SBM) of cyclophilin-like domain (CLD) of Ran-binding protein 2 (Ranbp2) expressed in a null Ranbp2 background lack untoward effects in photoreceptors in the absence of light-stress. However, compared to wild type photoreceptors, light-stress elicits profound disintegration of outer segments of Ranbp2(-/-)::Tg-Ranbp2(CLDm-HA) with paradoxical age-dependent resistance of photoreceptors to death and genotype-independent activation of caspases. Ranbp2(-/-)::Tg-Ranbp2(CLDm-HA) exhibit photoreceptor death-independent changes in ubiquitin-proteasome system (UPS), but death-dependent increase of ubiquitin carrier protein 9(ubc9) levels. Hence, insidious functional impairment of SBM of Ranbp2's CLD promotes neuroprotection and uncoupling of photoreceptor degeneration and death against phototoxicity. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Beyond Auditory Sensory Processing Deficits: Lexical Tone Perception Deficits in Chinese Children with Developmental Dyslexia

ERIC Educational Resources Information Center

Tong, Xiuhong; Tong, Xiuli; King Yiu, Fung

2018-01-01

Increasing evidence suggests that children with developmental dyslexia exhibit a deficit not only at the segmental level of phonological processing but also, by extension, at the suprasegmental level. However, it remains unclear whether such a suprasegmental phonological processing deficit is due to a difficulty in processing acoustic cues of…

Vibration-induced multifocal neuropathy in forestry workers: electrophysiological findings in relation to vibration exposure and finger circulation.

PubMed

Bovenzi, M; Giannini, F; Rossi, S

2000-11-01

To investigate neural conduction in the upper limbs of symptomatic forestry workers with and without exposure to hand-transmitted vibration. A further aim was to assess the possible relationships between vibration exposure, nerve conduction and finger circulation in the forestry workers who used chain saws. A detailed neurophysiological investigation was performed on the upper extremities of 20 chain saw workers, 20 forestry operators with heavy manual work but without vibration exposure, and 20 healthy male controls. All subjects were screened to exclude polyneuropathy. Measurements of sensory and motor nerve conduction (velocity and amplitude) were obtained bilaterally from the median, ulnar and radial nerves. To assess peripheral vascular function, the forestry workers underwent a cold test with plethysmographic measurement of finger systolic blood pressure (FSBP). In the chain saw operators, vibration exposure was evaluated according to the International Standard ISO 5349. Indices of daily vibration exposure and lifetime cumulative vibration dose were estimated for each chain saw operator. Sensory nerve conduction in several segments of the median and radial nerves was significantly reduced in the chain saw operators compared with that in the workers doing heavy manual work and the controls. The neurophysiological pattern more frequently observed in the chain saw operators was a multifocal nerve conduction impairment to several neural segments with predominant involvement of sensory rather than motor fibres. Sensory nerve conduction velocities in the hands of the chain saw operators were inversely related to both daily and lifetime cumulative vibration exposures. In the vibration-exposed forestry workers, neither were sensori-motor complaints associated with vascular symptoms (finger whiteness) nor were electrophysiological data related to cold-induced changes in FSBP. Exposure to hand-transmitted vibration, in addition to ergonomic stress factors, can contribute to peripheral nerve disorders occurring in forestry workers who operate chain saws. The findings of this study suggest the existence of an exposure-effect relationship for vibration-induced neuropathy. Different underlying mechanisms are likely to be involved in the pathogenesis of the neurological and vascular components of the hand-arm vibration syndrome.

Sensory blockade after thoracic paravertebral injection of ropivacaine or bupivacaine.

PubMed

Hura, G; Knapik, P; Misiołek, H; Krakus, A; Karpe, J

2006-08-01

No clinical trials comparing the characteristics of sensory blockade caused by various local anaesthetics in thoracic paravertebral blockade have been published. The aim of this prospective study was a clinical assessment of sensory blockade after paravertebral injection of ropivacaine or bupivacaine in patients undergoing modified radical mastectomy. Seventy ASA I-II patients were randomized to receive a single injection of ropivacaine 0.5% (n = 35) or bupivacaine 0.5% (n = 35) at the T4 level. General anaesthesia with propofol and fentanyl was provided during the procedure and patients were not intubated. The following parameters were analysed: duration and dynamics of the sensory blockade and the patient's and surgeon's assessment. Both ropivacaine and bupivacaine provided a similar level of analgesia. Ropivacaine was characterized by more rapid onset - after only 5 min 53% of patients in this group had the extent of sensory blockade wide enough to perform modified radical mastectomy in comparison to only 20% after bupivacaine (P 9 segments blocked) was noted more often in the ropivacaine group (88% vs. 65%, P < 0.05), lasted longer and appeared to be wider than sensory blockade produced by bupivacaine. Regression of sensory blockade was initially similar, but after 24 h sensory blockade in the ropivacaine group still had a potential to provide analgesia for modified radical mastectomy in 81% of patients in comparison to only 50% of such patients in the bupivacaine group (P < 0.05). Degree of postoperative pain, performance of the cardiovascular system, consumption of medications and complications were all similar between the study groups. Both agents provide satisfactory conditions for mastectomy, but ropivacaine seems to be superior to bupivacaine for thoracic paravertebral blockade during breast cancer surgery.

Apparatus and methods for impingement cooling of a side wall of a turbine nozzle segment

DOEpatents

Burdgick, Steven Sebastian

2002-01-01

A gas turbine nozzle segment has outer and inner bands and a vane therebetween. Each band includes a nozzle wall, a side wall, a cover and an impingement plate between the cover and the nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through apertures of the impingement plate to cool the nozzle wall. The side wall of the band and inturned flange define with the nozzle wall an undercut region. The impingement plate has a turned flange welded to the inturned flange. A backing plate overlies the turned flange and aligned apertures are formed through the backing plate and turned flange to direct and focus cooling flow onto the side wall of the nozzle segment.

Support pedestals for interconnecting a cover and nozzle band wall in a gas turbine nozzle segment

DOEpatents

Yu, Yufeng Phillip; Itzel, Gary Michael; Webbon, Waylon Willard; Bagepalli, Radhakrishna; Burdgick, Steven Sebastian; Kellock, Iain Robertson

2002-01-01

A gas turbine nozzle segment has outer and inner band portions. Each band portion includes a nozzle wall, a cover and an impingement plate between the cover and nozzle wall defining two cavities on opposite sides of the impingement plate. Cooling steam is supplied to one cavity for flow through the apertures of the impingement plate to cool the nozzle wall. Structural pedestals interconnect the cover and nozzle wall and pass through holes in the impingement plate to reduce localized stress otherwise resulting from a difference in pressure within the chamber of the nozzle segment and the hot gas path and the fixed turbine casing surrounding the nozzle stage. The pedestals may be cast or welded to the cover and nozzle wall.

Cytologic appearance of retinal cells included in a fine-needle aspirate of a meningioma around the optic nerve of a dog.

PubMed

Tvedten, Harold; Hillström, Anna

2013-06-01

A 6-year-old Wirehair Dachshund had a meningioma around the optic nerve that caused exophthalmos. A benign mesenchymal tumor was suspected based on the cytologic pattern of a fine-needle aspirate, and a meningioma was diagnosed by histopathologic examination. In addition to the meningioma cells, the cytologic smears included groups of cells from apparently 4 layers of normal retina. In particular, uniform rod-shaped structures in the cytologic sample could suggest rod-shaped bacteria, but these structures were identified as cylindrical outer segments of photoreceptor rod cells. Other retinal structures recognized included pigmented epithelial layer cells with their uniquely formed pigment granules, the characteristic bi-lobed, cleaved nuclei from the outer nuclear layer, and nerve tissue likely from the outer plexiform layer of the retina. © 2013 American Society for Veterinary Clinical Pathology.

Three-dimensional spectral domain optical coherence tomography in X linked foveal retinoschisis

PubMed Central

Saxena, Sandeep; Manisha; Meyer, Carsten H

2013-01-01

Spectral domain optical coherence tomography (SD-OCT) was performed in two cases of bilateral X linked foveal retinoschisis of different age groups. On fundus examination spoke wheel and honeycomb pattern of cysts were observed along with retinal nerve fibre layer (RNFL) defects. On SD-OCT, schisis was observed in the outer plexiform layer. External limiting membrane disruption was observed in the subfoveal area, along with disruption of outer nuclear layer (ONL) and inner–outer segment junction. Elevation of ONL due to tractional pull of central palisade was a novel observation. Retinoschisis extended beyond the optic disc up to the nasal region. Extracted RNFL tomogram presented an unprecedented visualisation of schisis along 360° of the optic disc. Tractional elevation in the foveal area and schisis involving nasal region, not observed upon clinical examination, was highlighted on SD-OCT. This investigative modality is an important adjunct in the assessment of foveal retinoschisis. PMID:23563673

Patterns of cell death in the embryonic antenna of the grasshopper Schistocerca gregaria.

PubMed

Boyan, George; Graf, Philip; Ehrhardt, Erica

2018-03-01

We have investigated the pattern of apoptosis in the antennal epithelium during embryonic development of the grasshopper Schistocerca gregaria. The molecular labels lachesin and annulin reveal that the antennal epithelium becomes subdivided into segment-like meristal annuli within which sensory cell clusters later differentiate. To determine whether apoptosis is involved in the development of such sensory cell clusters, we examined the expression pattern of the cell death labels acridine orange and TUNEL in the epithelium. We found stereotypic, age-dependent, wave-like patterns of cell death in the antenna. Early in embryogenesis, apoptosis is restricted to the most basal meristal annuli but subsequently spreads to encompass almost the entire antenna. Cell death then declines in more basal annuli and is only found in the tip region later in embryogenesis. Apoptosis is restricted throughout to the midregion of a given annulus and away from its border with neighboring annuli, arguing against a causal role in annular formation. Double-labeling for cell death and sensory cell differentiation reveals apoptosis occurring within bands of differentiating sensory cell clusters, matching the meristal organization of the apical antenna. Examination of the individual epithelial lineages which generate sensory cells reveals that apoptosis begins peripherally within a lineage and with age expands to encompass the differentiated sensory cell at the base. We conclude that complete lineages can undergo apoptosis and that the youngest cells in these lineages appear to die first, with the sensory neuron dying last. Lineage-based death in combination with cell death patterns in different regions of the antenna may contribute to odor-mediated behaviors in the grasshopper.

Distinct development of the trigeminal sensory nuclei in platypus and echidna.

PubMed

Ashwell, Ken W S; Hardman, Craig D

2012-01-01

Both lineages of the modern monotremes have been reported to be capable of electroreception using the trigeminal pathways and it has been argued that electroreception arose in an aquatic platypus-like ancestor of both modern monotreme groups. On the other hand, the trigeminal sensory nuclear complex of the platypus is highly modified for processing tactile and electrosensory information from the bill, whereas the trigeminal sensory nuclear complex of the short-beaked echidna (Tachyglossus aculeatus) is not particularly specialized. If the common ancestor for both platypus and echidna were an electroreceptively and trigeminally specialized aquatic feeder, one would expect the early stages of development of the trigeminal sensory nuclei in both species to show evidence of structural specialization from the outset. To determine whether this is the case, we examined the development of the trigeminal sensory nuclei in the platypus and short-beaked echidna using the Hill and Hubrecht embryological collections. We found that the highly specialized features of the platypus trigeminal sensory nuclei (i.e. the large size of the principal nucleus and oral part of the spinal trigeminal nuclear complex, and the presence of a dorsolateral parvicellular segment in the principal nucleus) appear around the time of hatching in the platypus, but are never seen at any stage in the echidna. Our findings support the proposition that the modern echidna and platypus are derived from a common ancestor with only minimal trigeminal specialization and that the peculiar anatomy of the trigeminal sensory nuclei in the modern platypus emerged in the ornithorhynchids after divergence from the tachyglossids. Copyright © 2012 S. Karger AG, Basel.

Morphology of immature stages of blow fly, Lucilia sinensis Aubertin (Diptera: Calliphoridae), a potential species of forensic importance.

PubMed

Sanit, Sangob; Sukontason, Kom; Kurahashi, Hiromu; Tomberlin, Jeffery K; Wannasan, Anchalee; Kraisittipanit, Rungroj; Sukontason, Kabkaew L

2017-12-01

Lucilia sinensis Aubertin (Diptera: Calliphoridae) is a blow fly species of potential forensic importance since adults are attracted to, and colonize, decomposing vertebrate remains. Blow fly larvae associated with human corpses can be useful evidence in forensic investigations; however, their use is dependent in most cases on proper species identification and availability of developmental data. For identification, morphological information on each life stage is traditionally used. We used scanning electron microscopy (SEM) to examine the ultrastructure of eggs, all instars, and puparia, of L. sinensis. The important characteristics used to differentiate L. sinensis from other species are provided. Distinctive features of the eggs are the slight widening median area extending almost the entire length. The last abdominal segment of the first instar bears elongated outer ventral tubercles along the rim of the last abdominal segment. These tubercles, as well as the well developed median and outer dorsal tubercles, are more prominent in the second and third instars. The surface integument of the tubercles is equipped with circular rows of microtrichia. Pairs of inner dorsal tubercle are absent. Each anterior spiracle is comprised of 9-12 papillae arrange in a single row in the second and third instars. As for the third instar, the dorsal spines between the first and second thoracic segments are delicate, narrow, small, and close together (as row or set). The peristigmatic tufts adjacent to the posterior spiracle of the third instar are moderately branches of short, fine hairs, but minute in puparia. In conclusion, the prominent outer ventral tubercle in all instars and puparia is a new diagnostic feature of L. sinensis and helpful in differentiating it from other Lucilia species that are forensically important. The description of immature L. sinensis in this study will be useful for forensic entomologists in countries where this species exists. Copyright © 2017 Elsevier B.V. All rights reserved.

Role of Caspase-3 in acute light damage to retina of rats.

PubMed

Wang, Xiao; Hu, Shi-Xing; Li, Wei; Lin, Shao-Chun

2007-03-01

To investigate the role of Caspase-3 in retinal damage caused by light exposure in rats. Light injury to retina was induced by persistent exposure to illumination (intensity: 30 000 +/- 50 lux) of operating microscope for 30 minutes in the right eyes of Sprague-Dawley rats. The pathological changes of retina were observed under optical and electron microscopies at different time points, which were 6 hours, 1, 3, 7, and 15 days after the light exposure. Apoptosis of retinal cells was analyzed by flow cytometry. The activity of Caspase-3 was evaluated by using the Caspase-3 assay kit. At the same time, the expression of Caspase-3 protease was determined with Western blot analysis. The examination results of optical and transmission electron microscopes showed that edema of inner and outer segments of the retina, especially the chondriosome inside the inner segment, became obvious 6 hours after the light exposure. The change was deteriorated along with the increasing time. The structures of the discoidal valve dissociated in the outer segment simultaneously. Disorderly arranged nuclei, karyopycnosis, and thinning in the outer nuclear layer were observed. The retinal pigment epithelium almost disappeared during the later stage. The staining results of Annexin-V combined with PI demonstrated that the proportion of apoptotic cells increased with time. The proportion between 7th day (82.7%) and 15th day (80.4%), however, showed no significant difference. Caspase-3 became remarkably active with the lapse of time, which increased from 0.02 at 6th hour to the peak of 9.8 at 7th day before it started to descend. The Western blot detected a expression of the active form of Caspase-3 at 7th day and 15th day. Apoptosis of photoreceptor cells is markedly involved in the light damage and Caspase-3 protease may play an important role in the apoptotic process of the retina after light exposure in rats.

Mfsd2a Is a Transporter for the Essential ω-3 Fatty Acid Docosahexaenoic Acid (DHA) in Eye and Is Important for Photoreceptor Cell Development.

PubMed

Wong, Bernice H; Chan, Jia Pei; Cazenave-Gassiot, Amaury; Poh, Rebecca W; Foo, Juat Chin; Galam, Dwight L A; Ghosh, Sujoy; Nguyen, Long N; Barathi, Veluchamy A; Yeo, Sia W; Luu, Chi D; Wenk, Markus R; Silver, David L

2016-05-13

Eye photoreceptor membrane discs in outer rod segments are highly enriched in the visual pigment rhodopsin and the ω-3 fatty acid docosahexaenoic acid (DHA). The eye acquires DHA from blood, but transporters for DHA uptake across the blood-retinal barrier or retinal pigment epithelium have not been identified. Mfsd2a is a newly described sodium-dependent lysophosphatidylcholine (LPC) symporter expressed at the blood-brain barrier that transports LPCs containing DHA and other long-chain fatty acids. LPC transport via Mfsd2a has been shown to be necessary for human brain growth. Here we demonstrate that Mfsd2a is highly expressed in retinal pigment epithelium in embryonic eye, before the development of photoreceptors, and is the primary site of Mfsd2a expression in the eye. Eyes from whole body Mfsd2a-deficient (KO) mice, but not endothelium-specific Mfsd2a-deficient mice, were DHA-deficient and had significantly reduced LPC/DHA transport in vivo Fluorescein angiography indicated normal blood-retinal barrier function. Histological and electron microscopic analysis indicated that Mfsd2a KO mice exhibited a specific reduction in outer rod segment length, disorganized outer rod segment discs, and mislocalization of and reduction in rhodopsin early in postnatal development without loss of photoreceptors. Minor photoreceptor cell loss occurred in adult Mfsd2a KO mice, but electroretinography indicated visual function was normal. The developing eyes of Mfsd2a KO mice had activated microglia and up-regulation of lipogenic and cholesterogenic genes, likely adaptations to loss of LPC transport. These findings identify LPC transport via Mfsd2a as an important pathway for DHA uptake in eye and for development of photoreceptor membrane discs. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Lateral diffusion of rhodopsin in photoreceptor membrane: a reappraisal.

PubMed

Govardovskii, Victor I; Korenyak, Darya A; Shukolyukov, Sergei A; Zueva, Lidia V

2009-08-28

In a series of works between 1972 and 1984, it was established that rhodopsin undergoes rotational and lateral Brownian motion in the plane of photoreceptor membrane. The concept of free movement of proteins of phototransduction cascade is an essential principle of the present scheme of vertebrate phototransduction. This has recently been challenged by findings that show that in certain conditions rhodopsin in the membrane may be dimeric and form extended areas of paracrystalline organization. Such organization seems incompatible with earlier data on free rhodopsin diffusion. Thus we decided to reinvestigate lateral diffusion of rhodopsin and products of its photolysis in photoreceptor membrane specifically looking for indications of possible oligomeric organization. Diffusion exchange by rhodopsin and its photoproducts between bleached and unbleached halves of rod outer segment was traced using high-speed dichroic microspectrophotometer. Measurements were conducted on amphibian (frog, toad, and salamander) and gecko rods. We found that the curves that are supposed to reflect the process of diffusion equilibration of rhodopsin in nonuniformly bleached outer segment largely show production of long-lived bleaching intermediate, metarhodopsin III (Meta III). After experimental elimination of Meta III contribution, we observed rhodopsin equilibration time constant was threefold to tenfold longer than estimated previously. However, after proper correction for the geometry of rod discs, it translates into generally accepted value of diffusion constant of approximately 5 x 10(-9) cm(2) s(-1). Yet, we found that there exists an immobile rhodopsin fraction whose size can vary from virtually zero to 100%, depending on poorly defined factors. Controls suggest that the formation of the immobile fraction is not due to fragmentation of rod outer segment discs but supposedly reflects oligomerization of rhodopsin. Implications of the new findings for the present model of phototransduction are discussed. We hypothesize that formation of paracrystalline areas, if controlled physiologically, could be an extra mechanism of cascade regulation.

The role of the notochord in amniote vertebral column segmentation.

PubMed

Ward, Lizzy; Pang, Angel S W; Evans, Susan E; Stern, Claudio D

2018-07-01

The vertebral column is segmented, comprising an alternating series of vertebrae and intervertebral discs along the head-tail axis. The vertebrae and outer portion (annulus fibrosus) of the disc are derived from the sclerotome part of the somites, whereas the inner nucleus pulposus of the disc is derived from the notochord. Here we investigate the role of the notochord in vertebral patterning through a series of microsurgical experiments in chick embryos. Ablation of the notochord causes loss of segmentation of vertebral bodies and discs. However, the notochord cannot segment in the absence of the surrounding sclerotome. To test whether the notochord dictates sclerotome segmentation, we grafted an ectopic notochord. We find that the intrinsic segmentation of the sclerotome is dominant over any segmental information the notochord may possess, and no evidence that the chick notochord is intrinsically segmented. We propose that the segmental pattern of vertebral bodies and discs in chick is dictated by the sclerotome, which first signals to the notochord to ensure that the nucleus pulposus develops in register with the somite-derived annulus fibrosus. Later, the notochord is required for maintenance of sclerotome segmentation as the mature vertebral bodies and intervertebral discs form. These results highlight differences in vertebral development between amniotes and teleosts including zebrafish, where the notochord dictates the segmental pattern. The relative importance of the sclerotome and notochord in vertebral patterning has changed significantly during evolution. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

Towards Artificial Speech Therapy: A Neural System for Impaired Speech Segmentation.

PubMed

Iliya, Sunday; Neri, Ferrante

2016-09-01

This paper presents a neural system-based technique for segmenting short impaired speech utterances into silent, unvoiced, and voiced sections. Moreover, the proposed technique identifies those points of the (voiced) speech where the spectrum becomes steady. The resulting technique thus aims at detecting that limited section of the speech which contains the information about the potential impairment of the speech. This section is of interest to the speech therapist as it corresponds to the possibly incorrect movements of speech organs (lower lip and tongue with respect to the vocal tract). Two segmentation models to detect and identify the various sections of the disordered (impaired) speech signals have been developed and compared. The first makes use of a combination of four artificial neural networks. The second is based on a support vector machine (SVM). The SVM has been trained by means of an ad hoc nested algorithm whose outer layer is a metaheuristic while the inner layer is a convex optimization algorithm. Several metaheuristics have been tested and compared leading to the conclusion that some variants of the compact differential evolution (CDE) algorithm appears to be well-suited to address this problem. Numerical results show that the SVM model with a radial basis function is capable of effective detection of the portion of speech that is of interest to a therapist. The best performance has been achieved when the system is trained by the nested algorithm whose outer layer is hybrid-population-based/CDE. A population-based approach displays the best performance for the isolation of silence/noise sections, and the detection of unvoiced sections. On the other hand, a compact approach appears to be clearly well-suited to detect the beginning of the steady state of the voiced signal. Both the proposed segmentation models display outperformed two modern segmentation techniques based on Gaussian mixture model and deep learning.

GUCY2D Cone-Rod Dystrophy-6 Is a "Phototransduction Disease" Triggered by Abnormal Calcium Feedback on Retinal Membrane Guanylyl Cyclase 1.

PubMed

Sato, Shinya; Peshenko, Igor V; Olshevskaya, Elena V; Kefalov, Vladimir J; Dizhoor, Alexander M

2018-03-21

The Arg838Ser mutation in retinal membrane guanylyl cyclase 1 (RetGC1) has been linked to autosomal dominant cone-rod dystrophy type 6 (CORD6). It is believed that photoreceptor degeneration is caused by the altered sensitivity of RetGC1 to calcium regulation via guanylyl cyclase activating proteins (GCAPs). To determine the mechanism by which this mutation leads to degeneration, we investigated the structure and function of rod photoreceptors in two transgenic mouse lines, 362 and 379, expressing R838S RetGC1. In both lines, rod outer segments became shorter than in their nontransgenic siblings by 3-4 weeks of age, before the eventual photoreceptor degeneration. Despite the shortening of their outer segments, the dark current of transgenic rods was 1.5-2.2-fold higher than in nontransgenic controls. Similarly, the dim flash response amplitude in R838S + rods was larger, time to peak was delayed, and flash sensitivity was increased, all suggesting elevated dark-adapted free cGMP in transgenic rods. In rods expressing R838S RetGC1, dark-current noise increased and the exchange current, detected after a saturating flash, became more pronounced. These results suggest disrupted Ca 2+ phototransduction feedback and abnormally high free-Ca 2+ concentration in the outer segments. Notably, photoreceptor degeneration, which typically occurred after 3 months of age in R838S RetGC1 transgenic mice in GCAP1,2 +/+ or GCAP1,2 +/- backgrounds, was prevented in GCAP1,2 -/- mice lacking Ca 2+ feedback to guanylyl cyclase. In summary, the dysregulation of guanylyl cyclase in RetGC1-linked CORD6 is a "phototransduction disease," which means it is associated with increased free-cGMP and Ca 2+ levels in photoreceptors. SIGNIFICANCE STATEMENT In a mouse model expressing human membrane guanylyl cyclase 1 (RetGC1, GUCY2D ), a mutation associated with early progressing congenital blindness, cone-rod dystrophy type 6 (CORD6), deregulates calcium-sensitive feedback of phototransduction to the cyclase mediated by guanylyl cyclase activating proteins (GCAPs), which are calcium-sensor proteins. The abnormal calcium sensitivity of the cyclase increases cGMP-gated dark current in the rod outer segments, reshapes rod photoresponses, and triggers photoreceptor death. This work is the first to demonstrate a direct physiological effect of GUCY2D CORD6-linked mutation on photoreceptor physiology in vivo It also identifies the abnormal regulation of the cyclase by calcium-sensor proteins as the main trigger for the photoreceptor death. Copyright © 2018 the authors 0270-6474/18/382990-11$15.00/0.

Spinal anaesthesia with midazolam in the rat.

PubMed

Bahar, M; Cohen, M L; Grinshpon, Y; Chanimov, M

1997-02-01

This study examined in an animal model whether intrathecal midazolam, alone or with fentanyl, can achieve anaesthesia sufficient for laparotomy, comparable to lidocaine. Effects on consciousness and whether anaesthesia was segmental were also examined. The haemodynamic and respiratory changes were compared with those of intrathecal lidocaine or intrathecal fentanyl alone. Sixty Wistar strain rats, with nylon catheters chronically implanted in the lumbar subarachnoid theca, were divided into six groups. Group 1 (n = 12) received 75 microL intrathecal lidocaine 2%. Group 2 (n = 12) received 75 microL intrathecal midazolam 0.1%, Group 3 (n = 12) received intrathecal 37.5 microL midazolam 0.1%, plus 37.5 microL fentanyl 0.005%. Group 4 (n = 12) received intrathecal 50 microL fentanyl 0.005%. Group 5 (n = 6) received 75 microL midazolam 0.1% iv. Group 6 (n = 6) received halothane 0.6% in oxygen by inhalation. Both groups that received intrathecal midazolam, alone or combined with fentanyl, developed effective segmental sensory and motor blockade of the hind limbs and abdominal wall, sufficient for a pain-free laparotomy procedure. Neither of these groups, unlike the group that received intrathecal lidocaine, developed a reduction in blood pressure or change in heart rate at the time of maximal sensory or motor blockade, nor were there changes in the arterial blood gases or respiratory rate. Midazolam, when injected intrathecally, produces reversible, segmental, spinally mediated antinociception, sufficient to provide balanced anaesthesia for abdominal surgery.

Film cooling for a closed loop cooled airfoil

DOEpatents

Burdgick, Steven Sebastian; Yu, Yufeng Phillip; Itzel, Gary Michael

2003-01-01

Turbine stator vane segments have radially inner and outer walls with vanes extending therebetween. The inner and outer walls are compartmentalized and have impingement plates. Steam flowing into the outer wall plenum passes through the impingement plate for impingement cooling of the outer wall upper surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. At least one film cooling hole is defined through a wall of at least one of the cavities for flow communication between an interior of the cavity and an exterior of the vane. The film cooling hole(s) are defined adjacent a potential low LCF life region, so that cooling medium that bleeds out through the film cooling hole(s) reduces a thermal gradient in a vicinity thereof, thereby the increase the LCF life of that region.

Exit chimney joint and method of forming the joint for closed circuit steam cooled gas turbine nozzles

DOEpatents

Burdgick, Steven Sebastian; Burns, James Lee

2002-01-01

A nozzle segment for a gas turbine includes inner and outer band portions and a vane extending between the band portions. The inner and outer band portions are each divided into first and second plenums separated by an impingement plate. Cooling steam is supplied to the first cavity for flow through the apertures to cool the outer nozzle wall. The steam flows through a leading edge cavity in the vane into the first cavity of the inner band portion for flow through apertures of the impingement plate to cool the inner nozzle wall. Spent cooling steam flows through a plurality of cavities in the vane, exiting through an exit chimney in the outer band. The exit chimney is secured at its inner end directly to the nozzle vane wall surrounding the exit cavities, to the margin of the impingement plate at a location intermediate the ends of the exit chimney and to margins of an opening through the cover whereby each joint is externally accessible for joint formation and for subsequent inspection.

Steam exit flow design for aft cavities of an airfoil

DOEpatents

Storey, James Michael; Tesh, Stephen William

2002-01-01

Turbine stator vane segments have inner and outer walls with vanes extending therebetween. The inner and outer walls have impingement plates. Steam flowing into the outer wall passes through the impingement plate for impingement cooling of the outer wall surface. The spent impingement steam flows into cavities of the vane having inserts for impingement cooling the walls of the vane. The steam passes into the inner wall and through the impingement plate for impingement cooling of the inner wall surface and for return through return cavities having inserts for impingement cooling of the vane surfaces. A skirt or flange structure is provided for shielding the steam cooling impingement holes adjacent the inner wall aerofoil fillet region of the nozzle from the steam flow exiting the aft nozzle cavities. Moreover, the gap between the flash rib boss and the cavity insert is controlled to minimize the flow of post impingement cooling media therebetween. This substantially confines outflow to that exiting via the return channels, thus furthermore minimizing flow in the vicinity of the aerofoil fillet region that may adversely affect impingement cooling thereof.

Nerve ultrasound shows subclinical peripheral nerve involvement in neurofibromatosis type 2.

PubMed

Telleman, Johan A; Stellingwerff, Menno D; Brekelmans, Geert J; Visser, Leo H

2018-02-01

Neurofibromatosis type 2 (NF2) is mainly associated with central nervous system (CNS) tumors. Peripheral nerve involvement is described in symptomatic patients, but evidence of subclinical peripheral nerve involvement is scarce. We conducted a cross-sectional pilot study in 2 asymptomatic and 3 minimally symptomatic patients with NF2 to detect subclinical peripheral nerve involvement. Patients underwent clinical examination, nerve conduction studies (NCS), and high-resolution ultrasonography (HRUS). A total of 30 schwannomas were found, divided over 20 nerve segments (33.9% of all investigated nerve segments). All patients had at least 1 schwannoma. Schwannomas were identified with HRUS in 37% of clinically unaffected nerve segments and 50% of nerve segments with normal NCS findings. HRUS shows frequent subclinical peripheral nerve involvement in NF2. Clinicians should consider peripheral nerve involvement as a cause of weakness and sensory loss in the extremities in patients with this disease. Muscle Nerve 57: 312-316, 2018. © 2017 Wiley Periodicals, Inc.

Cone structure in patients with usher syndrome type III and mutations in the Clarin 1 gene.

PubMed

Ratnam, Kavitha; Västinsalo, Hanna; Roorda, Austin; Sankila, Eeva-Marja K; Duncan, Jacque L

2013-01-01

To study macular structure and function in patients with Usher syndrome type III (USH3) caused by mutations in the Clarin 1 gene (CLRN1). High-resolution macular images were obtained by adaptive optics scanning laser ophthalmoscopy and spectral domain optical coherence tomography in 3 patients with USH3 and were compared with those of age-similar control subjects. Vision function measures included best-corrected visual acuity, kinetic and static perimetry, and full-field electroretinography. Coding regions of the CLRN1 gene were sequenced. CLRN1 mutations were present in all the patients; a 20-year-old man showed compound heterozygous mutations (p.N48K and p.S188X), and 2 unrelated women aged 25 and 32 years had homozygous mutations (p.N48K). Best-corrected visual acuity ranged from 20/16 to 20/40, with scotomas beginning at 3° eccentricity. The inner segment-outer segment junction or the inner segment ellipsoid band was disrupted within 1° to 4° of the fovea, and the foveal inner and outer segment layers were significantly thinner than normal. Cones near the fovea in patients 1 and 2 showed normal spacing, and the preserved region ended abruptly. Retinal pigment epithelial cells were visible in patient 3 where cones were lost. Cones were observed centrally but not in regions with scotomas, and retinal pigment epithelial cells were visible in regions without cones in patients with CLRN1 mutations. High-resolution measures of retinal structure demonstrate patterns of cone loss associated with CLRN1 mutations. These findings provide insight into the effect of CLRN1 mutations on macular cone structure, which has implications for the development of treatments for USH3. clinicaltrials.gov Identifier: NCT00254605.

Regulated efflux of photoreceptor outer segment-derived cholesterol by human RPE cells.

PubMed

Storti, Federica; Raphael, Gabriele; Griesser, Vera; Klee, Katrin; Drawnel, Faye; Willburger, Carolin; Scholz, Rebecca; Langmann, Thomas; von Eckardstein, Arnold; Fingerle, Jürgen; Grimm, Christian; Maugeais, Cyrille

2017-12-01

Genetic studies have linked age-related macular degeneration (AMD) to genes involved in high-density lipoprotein (HDL) metabolism, including ATP-binding cassette transporter A1 (ABCA1). The retinal pigment epithelium (RPE) handles large amounts of lipids, among others cholesterol, partially derived from internalized photoreceptor outer segments (OS) and lipids physiologically accumulate in the aging eye. To analyze the potential function of ABCA1 in the eye, we measured cholesterol efflux, the first step of HDL generation, in RPE cells. We show the expression of selected genes related to HDL metabolism in mouse and human eyecups as well as in ARPE-19 and human primary RPE cells. Immunofluorescence staining revealed localization of ABCA1 on both sides of polarized RPE cells. This was functionally confirmed by directional efflux to apolipoprotein AI (ApoA-I) of 3 H-labeled cholesterol given to the cells via serum or via OS. ABCA1 expression and activity was modulated using a liver-X-receptor (LXR) agonist and an ABCA1 neutralizing antibody, demonstrating that the efflux was ABCA1-dependent. We concluded that the ABCA1-mediated lipid efflux pathway, and hence HDL biosynthesis, is functional in RPE cells towards both the basal (choroidal) and apical (subretinal) space. Impaired activity of the pathway might cause age-related perturbations of lipid homeostasis in the outer retina and thus may contribute to disease development and/or progression. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of Peripapillary Sparing and Macular Involvement in Stargardt Disease (STGD1)

PubMed Central

Rhee, David W.; Smith, R. Theodore; Tsang, Stephen H.; Allikmets, Rando; Chang, Stanley; Lazow, Margot A.; Hood, Donald C.; Greenstein, Vivienne C.

2011-01-01

Purpose. To quantify and compare structure and function across the macula and peripapillary area in Stargardt disease (STGD1). Methods. Twenty-seven patients (27 eyes) and 12 age-similar controls (12 eyes) were studied. Patients were classified on the basis of full-field electroretinogram (ERG) results. Fundus autofluorescence (FAF) and spectral domain-optical coherence tomography (SD-OCT) horizontal line scans were obtained through the fovea and peripapillary area. The thicknesses of the outer nuclear layer plus outer plexiform layer (ONL+), outer segment (OS), and retinal pigment epithelium (RPE) were measured through the fovea, and peripapillary areas from 1° to 4° temporal to the optic disc edge using a computer-aided, manual segmentation technique. Visual sensitivities in the central 10° were assessed using microperimetry and related to retinal layer thicknesses. Results. Compared to the central macula, the differences between controls and patients in ONL+, OS, and RPE layer thicknesses were less in the nasal and temporal macula. Relative sparing of the ONL+ and/or OS layers was detected in the nasal (i.e., peripapillary) macula in 8 of 13 patients with extramacular disease on FAF; relative functional sparing was also detected in this subgroup. All 14 patients with disease confined to the central macula, as detected on FAF, showed ONL+ and OS layer thinning in regions of normal RPE thickness. Conclusions. Relative peripapillary sparing was detected in STGD1 patients with extramacular disease on FAF. Photoreceptor thinning may precede RPE degeneration in STGD1. PMID:21873672

Alterations in Retinal Layer Thickness and Reflectance at Different Stages of Diabetic Retinopathy by En Face Optical Coherence Tomography

PubMed Central

Wanek, Justin; Blair, Norman P.; Chau, Felix Y.; Lim, Jennifer I.; Leiderman, Yannek I.; Shahidi, Mahnaz

2016-01-01

Purpose This article reports a method for en face optical coherence tomography (OCT) imaging and quantitative assessment of alterations in both thickness and reflectance of individual retinal layers at different stages of diabetic retinopathy (DR). Methods High-density OCT raster volume scans were acquired in 29 diabetic subjects divided into no DR (NDR) or non-proliferative DR (NPDR) groups and 22 control subjects (CNTL). A customized image segmentation method identified eight retinal layer interfaces and generated en face thickness maps and reflectance images for nerve fiber layer (NFL), ganglion cell and inner plexiform layers (GCLIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor outer segment layer (OSL), and retinal pigment epithelium (RPE). Mean thickness and intensity values were calculated in nine macular subfields for each retinal layer. Results En face thickness maps and reflectance images of retinal layers in CNTL subjects corresponded to normal retinal anatomy. Total retinal thickness correlated negatively with age in nasal subfields (R ≤−0.31; P ≤ 0.03, N = 51). In NDR subjects, NFL and OPL thickness were decreased (P = 0.05), and ONL thickness was increased (P = 0.04) compared to CNTL. In NPDR subjects, GCLIPL thickness was increased in perifoveal subfields (P < 0.05) and INL intensity was higher in all macular subfields (P = 0.04) compared to CNTL. Conclusions Depth and spatially resolved retinal thickness and reflectance measurements are potential biomarkers for assessment and monitoring of DR. PMID:27409491

CT volumetry of the skeletal tissues

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brindle, James M.; Alexandre Trindade, A.; Pichardo, Jose C.

2006-10-15

Computed tomography (CT) is an important and widely used modality in the diagnosis and treatment of various cancers. In the field of molecular radiotherapy, the use of spongiosa volume (combined tissues of the bone marrow and bone trabeculae) has been suggested as a means to improve the patient-specificity of bone marrow dose estimates. The noninvasive estimation of an organ volume comes with some degree of error or variation from the true organ volume. The present study explores the ability to obtain estimates of spongiosa volume or its surrogate via manual image segmentation. The variation among different segmentation raters was exploredmore » and found not to be statistically significant (p value >0.05). Accuracy was assessed by having several raters manually segment a polyvinyl chloride (PVC) pipe with known volumes. Segmentation of the outer region of the PVC pipe resulted in mean percent errors as great as 15% while segmentation of the pipe's inner region resulted in mean percent errors within {approx}5%. Differences between volumes estimated with the high-resolution CT data set (typical of ex vivo skeletal scans) and the low-resolution CT data set (typical of in vivo skeletal scans) were also explored using both patient CT images and a PVC pipe phantom. While a statistically significant difference (p value <0.002) between the high-resolution and low-resolution data sets was observed with excised femoral heads obtained following total hip arthroplasty, the mean difference between high-resolution and low-resolution data sets was found to be only 1.24 and 2.18 cm{sup 3} for spongiosa and cortical bone, respectively. With respect to differences observed with the PVC pipe, the variation between the high-resolution and low-resolution mean percent errors was a high as {approx}20% for the outer region volume estimates and only as high as {approx}6% for the inner region volume estimates. The findings from this study suggest that manual segmentation is a reasonably accurate and reliable means for the in vivo estimation of spongiosa volume. This work also provides a foundation for future studies where spongiosa volumes are estimated by various raters in more comprehensive CT data sets.« less

Protein and Signaling Networks in Vertebrate Photoreceptor Cells

PubMed Central

Koch, Karl-Wilhelm; Dell’Orco, Daniele

2015-01-01

Vertebrate photoreceptor cells are exquisite light detectors operating under very dim and bright illumination. The photoexcitation and adaptation machinery in photoreceptor cells consists of protein complexes that can form highly ordered supramolecular structures and control the homeostasis and mutual dependence of the secondary messengers cyclic guanosine monophosphate (cGMP) and Ca2+. The visual pigment in rod photoreceptors, the G protein-coupled receptor rhodopsin is organized in tracks of dimers thereby providing a signaling platform for the dynamic scaffolding of the G protein transducin. Illuminated rhodopsin is turned off by phosphorylation catalyzed by rhodopsin kinase (GRK1) under control of Ca2+-recoverin. The GRK1 protein complex partly assembles in lipid raft structures, where shutting off rhodopsin seems to be more effective. Re-synthesis of cGMP is another crucial step in the recovery of the photoresponse after illumination. It is catalyzed by membrane bound sensory guanylate cyclases (GCs) and is regulated by specific neuronal Ca2+-sensor proteins called guanylate cyclase-activating proteins (GCAPs). At least one GC (ROS-GC1) was shown to be part of a multiprotein complex having strong interactions with the cytoskeleton and being controlled in a multimodal Ca2+-dependent fashion. The final target of the cGMP signaling cascade is a cyclic nucleotide-gated (CNG) channel that is a hetero-oligomeric protein located in the plasma membrane and interacting with accessory proteins in highly organized microdomains. We summarize results and interpretations of findings related to the inhomogeneous organization of signaling units in photoreceptor outer segments. PMID:26635520

Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging

NASA Astrophysics Data System (ADS)

Zholudeva, Lyandysha V.; Ward, Kristina G.; Nichols, Michael G.; Smith, Heather Jensen

2015-05-01

Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs.

Gentamicin differentially alters cellular metabolism of cochlear hair cells as revealed by NAD(P)H fluorescence lifetime imaging

PubMed Central

Zholudeva, Lyandysha V.; Ward, Kristina G.; Nichols, Michael G.; Smith, Heather Jensen

2015-01-01

Abstract. Aminoglycoside antibiotics are implicated as culprits of hearing loss in more than 120,000 individuals annually. Research has shown that the sensory cells, but not supporting cells, of the cochlea are readily damaged and/or lost after use of such antibiotics. High-frequency outer hair cells (OHCs) show a greater sensitivity to antibiotics than high- and low-frequency inner hair cells (IHCs). We hypothesize that variations in mitochondrial metabolism account for differences in susceptibility. Fluorescence lifetime microscopy was used to quantify changes in NAD(P)H in sensory and supporting cells from explanted murine cochleae exposed to mitochondrial uncouplers, inhibitors, and an ototoxic antibiotic, gentamicin (GM). Changes in metabolic state resulted in a redistribution of NAD(P)H between subcellular fluorescence lifetime pools. Supporting cells had a significantly longer lifetime than sensory cells. Pretreatment with GM increased NAD(P)H intensity in high-frequency sensory cells, as well as the NAD(P)H lifetime within IHCs. GM specifically increased NAD(P)H concentration in high-frequency OHCs, but not in IHCs or pillar cells. Variations in NAD(P)H intensity in response to mitochondrial toxins and GM were greatest in high-frequency OHCs. These results demonstrate that GM rapidly alters mitochondrial metabolism, differentially modulates cell metabolism, and provides evidence that GM-induced changes in metabolism are significant and greatest in high-frequency OHCs. PMID:25688541

Sensor-Motor Maps for Describing Linear Reflex Composition in Hopping.

PubMed

Schumacher, Christian; Seyfarth, André

2017-01-01

In human and animal motor control several sensory organs contribute to a network of sensory pathways modulating the motion depending on the task and the phase of execution to generate daily motor tasks such as locomotion. To better understand the individual and joint contribution of reflex pathways in locomotor tasks, we developed a neuromuscular model that describes hopping movements. In this model, we consider the influence of proprioceptive length (LFB), velocity (VFB) and force feedback (FFB) pathways of a leg extensor muscle on hopping stability, performance and efficiency (metabolic effort). Therefore, we explore the space describing the blending of the monosynaptic reflex pathway gains. We call this reflex parameter space a sensor-motor map . The sensor-motor maps are used to visualize the functional contribution of sensory pathways in multisensory integration. We further evaluate the robustness of these sensor-motor maps to changes in tendon elasticity, body mass, segment length and ground compliance. The model predicted that different reflex pathway compositions selectively optimize specific hopping characteristics (e.g., performance and efficiency). Both FFB and LFB were pathways that enable hopping. FFB resulted in the largest hopping heights, LFB enhanced hopping efficiency and VFB had the ability to disable hopping. For the tested case, the topology of the sensor-motor maps as well as the location of functionally optimal compositions were invariant to changes in system designs (tendon elasticity, body mass, segment length) or environmental parameters (ground compliance). Our results indicate that different feedback pathway compositions may serve different functional roles. The topology of the sensor-motor map was predicted to be robust against changes in the mechanical system design indicating that the reflex system can use different morphological designs, which does not apply for most robotic systems (for which the control often follows a specific design). Consequently, variations in body mechanics are permitted with consistent compositions of sensory feedback pathways. Given the variability in human body morphology, such variations are highly relevant for human motor control.

Whole abdominal wall segmentation using augmented active shape models (AASM) with multi-atlas label fusion and level set

NASA Astrophysics Data System (ADS)

Xu, Zhoubing; Baucom, Rebeccah B.; Abramson, Richard G.; Poulose, Benjamin K.; Landman, Bennett A.

2016-03-01

The abdominal wall is an important structure differentiating subcutaneous and visceral compartments and intimately involved with maintaining abdominal structure. Segmentation of the whole abdominal wall on routinely acquired computed tomography (CT) scans remains challenging due to variations and complexities of the wall and surrounding tissues. In this study, we propose a slice-wise augmented active shape model (AASM) approach to robustly segment both the outer and inner surfaces of the abdominal wall. Multi-atlas label fusion (MALF) and level set (LS) techniques are integrated into the traditional ASM framework. The AASM approach globally optimizes the landmark updates in the presence of complicated underlying local anatomical contexts. The proposed approach was validated on 184 axial slices of 20 CT scans. The Hausdorff distance against the manual segmentation was significantly reduced using proposed approach compared to that using ASM, MALF, and LS individually. Our segmentation of the whole abdominal wall enables the subcutaneous and visceral fat measurement, with high correlation to the measurement derived from manual segmentation. This study presents the first generic algorithm that combines ASM, MALF, and LS, and demonstrates practical application for automatically capturing visceral and subcutaneous fat volumes.

Ceramic turbine stator vane and shroud support

DOEpatents

Glenn, Robert G.

1981-01-01

A support system for supporting the stationary ceramic vanes and ceramic outer shrouds which define the motive fluid gas path in a gas turbine engine is shown. Each individual segment of the ceramic component whether a vane or shroud segment has an integral radially outwardly projecting stem portion. The stem is enclosed in a split collet member of a high-temperature alloy material having a cavity configured to interlock with the stem portion. The generally cylindrical external surface of the collet engages a mating internal cylindrical surface of an aperture through a supporting arcuate ring segment with mating camming surfaces on the two facing cylindrical surfaces such that radially outward movement of the collet relative to the ring causes the internal cavity of the collet to be reduced in diameter to tightly engage the ceramic stem disposed therein. A portion of the collet extends outwardly through the ring segment opposite the ceramic piece and is threaded for receiving a nut and a compression washer for retaining the collet in the ring segment under a continuous biasing force urging the collet radially outwardly.

Delivery of Alginate Scaffold Releasing Two Trophic Factors for Spinal Cord Injury Repair

PubMed Central

Grulova, I.; Slovinska, L.; Blaško, J.; Devaux, S.; Wisztorski, M.; Salzet, M.; Fournier, I.; Kryukov, O.; Cohen, S.; Cizkova, D.

2015-01-01

Spinal cord injury (SCI) has been implicated in neural cell loss and consequently functional motor and sensory impairment. In this study, we propose an alginate -based neurobridge enriched with/without trophic growth factors (GFs) that can be utilized as a therapeutic approach for spinal cord repair. The bioavailability of key GFs, such as Epidermal Growth factor (EGF) and basic Fibroblast Growth Factor (bFGF) released from injected alginate biomaterial to the central lesion site significantly enhanced the sparing of spinal cord tissue and increased the number of surviving neurons (choline acetyltransferase positive motoneurons) and sensory fibres. In addition, we document enhanced outgrowth of corticospinal tract axons and presence of blood vessels at the central lesion. Tissue proteomics was performed at 3, 7 and 10 days after SCI in rats indicated the presence of anti-inflammatory factors in segments above the central lesion site, whereas in segments below, neurite outgrowth factors, inflammatory cytokines and chondroitin sulfate proteoglycan of the lectican protein family were overexpressed. Collectively, based on our data, we confirm that functional recovery was significantly improved in SCI groups receiving alginate scaffold with affinity-bound growth factors (ALG +GFs), compared to SCI animals without biomaterial treatment. PMID:26348665

Classification and characterization of Japanese consumers' beef preferences by external preference mapping.

PubMed

Sasaki, Keisuke; Ooi, Motoki; Nagura, Naoto; Motoyama, Michiyo; Narita, Takumi; Oe, Mika; Nakajima, Ikuyo; Hagi, Tatsuro; Ojima, Koichi; Kobayashi, Miho; Nomura, Masaru; Muroya, Susumu; Hayashi, Takeshi; Akama, Kyoko; Fujikawa, Akira; Hokiyama, Hironao; Kobayashi, Kuniyuki; Nishimura, Takanori

2017-08-01

Over the past few decades, beef producers in Japan have improved marbling in their beef products. It was recently reported that marbling is not well correlated with palatability as rated by Japanese consumers. This study sought to identify the consumer segments in Japan that prefer sensory characteristics of beef other than high marbling. Three Wagyu beef, one Holstein beef and two lean imported beef longissimus samples were subjected to a descriptive sensory test, physicochemical analysis and a consumer (n = 307) preference test. According to consumer classification and external preference mapping, four consumer segments were identified as 'gradual high-fat likers', 'moderate-fat and distinctive taste likers', 'Wagyu likers' and 'distinctive texture likers'. Although the major trend of Japanese consumers' beef preference was 'marbling liking', 16.9% of the consumers preferred beef samples that had moderate marbling and distinctive taste. The consumers' attitudes expressed in a questionnaire survey were in good agreement with the preference for marbling among the 'moderate-fat and distinctive taste likers'. These results indicate that moderately marbled beef is a potent category in the Japanese beef market. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Ontogenetic Development of Vestibulo-Ocular Reflexes in Amphibians

PubMed Central

Branoner, Francisco; Chagnaud, Boris P.; Straka, Hans

2016-01-01

Vestibulo-ocular reflexes (VOR) ensure gaze stability during locomotion and passively induced head/body movements. In precocial vertebrates such as amphibians, vestibular reflexes are required very early at the onset of locomotor activity. While the formation of inner ears and the assembly of sensory-motor pathways is largely completed soon after hatching, angular and translational/tilt VOR display differential functional onsets and mature with different time courses. Otolith-derived eye movements appear immediately after hatching, whereas the appearance and progressive amelioration of semicircular canal-evoked eye movements is delayed and dependent on the acquisition of sufficiently large semicircular canal diameters. Moreover, semicircular canal functionality is also required to tune the initially omnidirectional otolith-derived VOR. The tuning is due to a reinforcement of those vestibulo-ocular connections that are co-activated by semicircular canal and otolith inputs during natural head/body motion. This suggests that molecular mechanisms initially guide the basic ontogenetic wiring, whereas semicircular canal-dependent activity is required to establish the spatio-temporal specificity of the reflex. While a robust VOR is activated during passive head/body movements, locomotor efference copies provide the major source for compensatory eye movements during tail- and limb-based swimming of larval and adult frogs. The integration of active/passive motion-related signals for gaze stabilization occurs in central vestibular neurons that are arranged as segmentally iterated functional groups along rhombomere 1–8. However, at variance with the topographic maps of most other sensory systems, the sensory-motor transformation of motion-related signals occurs in segmentally specific neuronal groups defined by the extraocular motor output targets. PMID:27877114

Changes in Head Stability Control in Response to a Lateral Perturbation while Walking in Older Adults

NASA Technical Reports Server (NTRS)

Buccello, Regina R.; Cromwell, Ronita L.; Bloomberg, Jacob J.

2008-01-01

Falling is a main contributor of injury in older adults. The decline in sensory systems associated with aging limits information needed to successfully compensate for unexpected perturbations. Therefore, sensory changes result in older adults having problems maintaining balance stability when experiencing an unexpected lateral perturbation (e.g. slip) in the environment. The goal of this study was to determine head stability movement strategies used by older adults when experiencing an unexpected lateral perturbation during walking. A total of 16 healthy adults, aged 66-81 years, walked across a foam pathway 6 times. One piece of the foam pathway covered a movable platform that translated to the left when the subject stepped on the foam. Three trials were randomized in which the platform shifted. Angular rate sensors were placed on the center of mass for the head and trunk segments to collect head and trunk movement in all three planes of motion. The predominant movement strategies for maintaining head stability were determined from the results of the cross-correlation analyses between the head and trunk segments. The Chi square test of independence was used to evaluate the movement pattern distributions of head-trunk coordination during perturbed and non-perturbed walking. When perturbed, head stabilization was significantly challenged in the yaw and roll planes of motion. Subjects demonstrated a movement pattern of the head leading the trunk in an effort to stabilize the head. The older adult subjects used this head stabilization movement pattern to compensate for sensory changes when experiencing the unexpected lateral perturbation.

Displacement coefficients along the inner boundaries of radially cracked ring segments subject to forces and couples

NASA Technical Reports Server (NTRS)

Gross, B.

1978-01-01

Displacement results of plane boundary collocation analysis are given for various locations on the inner boundaries of radially cracked ring segments (C-shaped specimens) subject to two complementary types of loading. Results are presented for ratios of outer to inner radius in the range of 1.1 to 2.5 and ratios a/W in the range 0.1 to 0.8, where a is the crack length for a specimen of wall thickness W. By combination of these results the resultant displacement coefficient or the corresponding influence coefficient can be obtained for any practical load line location of a pin-loaded specimen.

Airfoil nozzle and shroud assembly

DOEpatents

Shaffer, J.E.; Norton, P.F.

1997-06-03

An airfoil and nozzle assembly are disclosed including an outer shroud having a plurality of vane members attached to an inner surface and having a cantilevered end. The assembly further includes a inner shroud being formed by a plurality of segments. Each of the segments having a first end and a second end and having a recess positioned in each of the ends. The cantilevered end of the vane member being positioned in the recess. The airfoil and nozzle assembly being made from a material having a lower rate of thermal expansion than that of the components to which the airfoil and nozzle assembly is attached. 5 figs.

Nozzle insert for mixed mode fuel injector

DOEpatents

Lawrence, Keith E [Peoria, IL

2006-11-21

A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set controlled respectively, by first and second needle valve members. The homogeneous charged nozzle outlet set is defined by a nozzle insert that is attached to an injector body, which defines the conventional nozzle outlet set. The nozzle insert is a one piece metallic component with a large diameter segment separated from a small diameter segment by an annular engagement surface. One of the needle valve members is guided on an outer surface of the nozzle insert, and the nozzle insert has an interference fit attachment to the injector body.

Pressure actuated film riding seals for turbo machinery

DOEpatents

Bidkar, Rahul Anil; Thatte, Azam Mihir; Gibson, Nathan Evan McCurdy; Giametta, Andrew Paul

2015-08-25

A seal assembly for a rotary machine is provided. The seal assembly includes multiple sealing device segments disposed circumferentially intermediate to a stationary housing and a rotor. Each of the sealing device segments includes a stator interface element, a shoe plate having an extended portion having one or more labyrinth teeth facing the rotor and a load bearing portion, wherein the shoe plate is configured to generate an aerodynamic force between the shoe plate and the rotor. The sealing device segment further includes a secondary seal configured to be in contact with the stator interface element at a radially outer end and configured to be in contact with an elevated nose section of the extended portion of the shoe plate on a radially inner end; and multiple flexible elements attached to the shoe plate and to the stator interface element.

Action Enhances Acoustic Cues for 3-D Target Localization by Echolocating Bats

PubMed Central

Wohlgemuth, Melville J.

2016-01-01

Under natural conditions, animals encounter a barrage of sensory information from which they must select and interpret biologically relevant signals. Active sensing can facilitate this process by engaging motor systems in the sampling of sensory information. The echolocating bat serves as an excellent model to investigate the coupling between action and sensing because it adaptively controls both the acoustic signals used to probe the environment and movements to receive echoes at the auditory periphery. We report here that the echolocating bat controls the features of its sonar vocalizations in tandem with the positioning of the outer ears to maximize acoustic cues for target detection and localization. The bat’s adaptive control of sonar vocalizations and ear positioning occurs on a millisecond timescale to capture spatial information from arriving echoes, as well as on a longer timescale to track target movement. Our results demonstrate that purposeful control over sonar sound production and reception can serve to improve acoustic cues for localization tasks. This finding also highlights the general importance of movement to sensory processing across animal species. Finally, our discoveries point to important parallels between spatial perception by echolocation and vision. PMID:27608186

Bicarbonate Modulates Photoreceptor Guanylate Cyclase (ROS-GC) Catalytic Activity.

PubMed

Duda, Teresa; Wen, Xiao-Hong; Isayama, Tomoki; Sharma, Rameshwar K; Makino, Clint L

2015-04-24

By generating the second messenger cGMP in retinal rods and cones, ROS-GC plays a central role in visual transduction. Guanylate cyclase-activating proteins (GCAPs) link cGMP synthesis to the light-induced fall in [Ca(2+)]i to help set absolute sensitivity and assure prompt recovery of the response to light. The present report discloses a surprising feature of this system: ROS-GC is a sensor of bicarbonate. Recombinant ROS-GCs synthesized cGMP from GTP at faster rates in the presence of bicarbonate with an ED50 of 27 mM for ROS-GC1 and 39 mM for ROS-GC2. The effect required neither Ca(2+) nor use of the GCAPs domains; however, stimulation of ROS-GC1 was more powerful in the presence of GCAP1 or GCAP2 at low [Ca(2+)]. When applied to retinal photoreceptors, bicarbonate enhanced the circulating current, decreased sensitivity to flashes, and accelerated flash response kinetics. Bicarbonate was effective when applied either to the outer or inner segment of red-sensitive cones. In contrast, bicarbonate exerted an effect when applied to the inner segment of rods but had little efficacy when applied to the outer segment. The findings define a new regulatory mechanism of the ROS-GC system that affects visual transduction and is likely to affect the course of retinal diseases caused by cGMP toxicity. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Interactions between charged residues in the transmembrane segments of the voltage-sensing domain in the hERG channel.

PubMed

Zhang, M; Liu, J; Jiang, M; Wu, D-M; Sonawane, K; Guy, H R; Tseng, G-N

2005-10-01

Studies on voltage-gated K channels such as Shaker have shown that positive charges in the voltage-sensor (S4) can form salt bridges with negative charges in the surrounding transmembrane segments in a state-dependent manner, and different charge pairings can stabilize the channels in closed or open states. The goal of this study is to identify such charge interactions in the hERG channel. This knowledge can provide constraints on the spatial relationship among transmembrane segments in the channel's voltage-sensing domain, which are necessary for modeling its structure. We first study the effects of reversing S4's positive charges on channel activation. Reversing positive charges at the outer (K525D) and inner (K538D) ends of S4 markedly accelerates hERG activation, whereas reversing the 4 positive charges in between either has no effect or slows activation. We then use the 'mutant cycle analysis' to test whether D456 (outer end of S2) and D411 (inner end of S1) can pair with K525 and K538, respectively. Other positive charges predicted to be able, or unable, to interact with D456 or D411 are also included in the analysis. The results are consistent with predictions based on the distribution of these charged residues, and confirm that there is functional coupling between D456 and K525 and between D411 and K538.

Optical extensometer

DOEpatents

Walker, Ray A.; Reich, Fred R.; Russell, James T.

1978-01-01

An optical extensometer is described using sequentially pulsed light beams for measuring the dimensions of objects by detecting two opposite edges of the object without contacting the object. The light beams may be of different distinguishable light characteristics, such as polarization or wave length, and are time modulated in an alternating manner at a reference frequency. The light characteristics are of substantially the same total light energy and are distributed symmetrically. In the preferred embodiment two light beam segments of one characteristic are on opposite sides of a middle segment of another characteristic. As a result, when the beam segments are scanned sequentially across two opposite edges of the object, they produce a readout signal at the output of a photoelectric detector that is compared with the reference signal by a phase comparator to produce a measurement signal with a binary level transition when the light beams cross an edge. The light beams may be of different cross sectional geometries, including two superimposed and concentric circular beam cross sections of different diameter, or two rectangular cross sections which intersect with each other substantially perpendicular so only their central portions are superimposed. Alternately, a row of three light beams can be used including two outer beams on opposite sides and separate from a middle beam. The three beams may all be of the same light characteristic. However it is preferable that the middle beam be of a different characteristic but of the same total energy as the two outer beams.

[Clinical and electrophysiological findings in carpal tunnel syndrome].

PubMed

Kohara, Nobuo

2007-11-01

Carpal tunnel syndrome (CTS) is the most common nerve entrapment disorder. The clinical features of CTS are variable, but usually include pain and paresthesia in the thumb, first two fingers, and the radial-half of the ring finger. Paresthesia and sensory deficits might involve the entire palm area in some cases. Pain frequently radiate proximally into the forearm, and occasionally to the shoulder. Many patients experience pain at night and are awakened by abnormal sensations. Shaking hand relief the symptom. The two classic tests for nerve compression at the wrist are the Tinel test and the Phalen maneuver, which diagnostic value is limited. Golden standard for the diagnosis is the combination of the clinical findings and the electrophysiological study. Routine median nerve conduction study is valuable. Prolonged terminal latency of motor or sensory nerve would be found in most CTS hands. If the routine study showed equivocal, more sensitive methods are needed. Those include segmental sensory conduction study across the carpal tunnel by median stimulation at midpalm, a comparison of median and ulnar sensory nerve latencies at ring finger and a comparison of median and radial sensory nerve latencies at thumb. A difference between the median motor latency to the second lumbrical and the ulnar motor latency to the interossei muscles has also diagnostic value in some cases. In addition, inching method can localized the compression site. Using these techniques, the diagnosis of CTS would become more reliable.

Electron Microscopic Alterations in Pediculus humanus capitis Exposed to Some Pediculicidal Plant Extracts

PubMed Central

Akkad, Dina M. H. El; El-Gebaly, Naglaa Saad M.; Yousof, Hebat-Allah Salah A.; Ismail, Mousa A. M.

2016-01-01

Head lice, Pediculus humanus capitis, infestation is an important public health problem in Egypt. Inadequate application of topical pediculicides and the increasing resistance to the commonly used pediculicides made the urgent need for the development of new agents able to induce irreversible changes in the exposed lice leading to their mortality. The aim of the present work is to evaluate pediculicidal efficacy of some natural products such as olive oil, tea tree oil, lemon juice, and ivermectin separately in comparison with tetramethrin-piperonyl butoxide (licid), as a standard pediculicide commonly used in Egypt. The effects of these products were evaluated by direct observation using dissecting and scanning electron microscopes (SEM). Results showed that after 1 hr exposure time in vitro, absolute (100%) mortalities were recorded after exposure to 1% ivermectin and fresh concentrate lemon juice. The mortalities were decreased to 96.7% after exposure to tea tree oil. Very low percentage of mortality (23.3%) was recorded after 1 hr of exposure to extra virgin olive oil. On the other hand, the reference pediculicide (licid) revealed only mortality rate of 93.3%. On the contrary, no mortalities were recorded in the control group exposed to distilled water. By SEM examination, control lice preserved outer smooth architecture, eyes, antenna, respiratory spiracles, sensory hairs, and legs with hook-like claws. In contrast, dead lice which had been exposed to pediculicidal products showed damage of outer smooth architecture, sensory hairs, respiratory spiracles and/or clinching claws according to pediculicidal products used. PMID:27658606

Acute tissue reactions, inner segment pathology, and effects of the antioxidant α1-microglobulin in an in vitro model of retinal detachment.

PubMed

Ghosh, Fredrik; Åkerström, Bo; Bergwik, Jesper; Abdshill, Hodan; Gefors, Lina; Taylor, Linnéa

2018-04-18

The purpose of this study was to explore acute tissue reactions, ultrastructural photoreceptor morphology with emphasis on inner segments, and the effect of antioxidant treatment in an in vitro model of rhegmatogenous retinal detachment (RRD). A previously described method of RRD simulation was used with adult retinal porcine explants kept free-floating in culture medium with or without treatment with the radical scavenger α 1 -microglobulin (A1M). Explants were examined at 5 time points from 1 to 24 h using transmission electron microscopy as well as quantitative real-time PCR (RT-PCR) to quantify gene expression of the cell stress marker heat shock protein 70 (Hsp70) and oxidative stress marker heme oxygenase (HO-1). The culture medium level of the cell damage marker lactate dehydrogenase (LDH) and oxidative stress DNA damage marker 8-Oxo-2'-deoxyguanosine (8-OHdG) was also assessed at each time point. We found that the levels of Hsp70 and LDH rapidly increased in both groups, and at 3 and 6 h, Hsp70 was significantly higher in A1M treated retinas. At 24 h, Hsp70 and LDH, as well as 8-OHdG were significantly lower compared with controls, whereas the tissue level of HO-1 was significantly higher. Progressive ultrastructural photoreceptor changes were seen in untreated control explants from 1 h and onwards including outer segment shortening and loss, disruption of organelles within the inner segments and loss of perikarya in the outer nuclear layer. Inner segment pathology was more rapid and extensive in rods compared with in cones. In A1M treated counterparts, damage to rod inner segment mitochondria was significantly higher after 1 h of culture, but after this time, no statistical difference was found. At 24 h, cone inner segment mitochondrial disruption was significantly higher in control retinas and the number of surviving perikarya lower. From our results, we conclude that retinal explants elicit acute cell stress reactions when placed in culture without physical support simulating a detached retina floating in the vitreous space. Photoreceptors rapidly display degenerative changes including extensive damage to inner segment mitochondria indicating loss of energy transduction as an early key event. A1M increases initial mitochondrial stress in the rods, however, subsequent pathology is attenuated by the treatment, highlighting the dynamics of protective as well as disruptive oxidative stress reactions in the detached retina. Copyright © 2018 Elsevier Ltd. All rights reserved.

Milk fat threshold determination and the effect of milk fat content on consumer preference for fluid milk.

PubMed

McCarthy, K S; Lopetcharat, K; Drake, M A

2017-03-01

Milk consumption in the United States has been in decline since the 1960s. Milk fat plays a critical role in sensory properties of fluid milk. The first objective of this study was to determine the change in percent milk fat needed to produce a detectable or just noticeable difference (JND) to consumers in skim, 1%, 2%, and whole milks. The second objective was to evaluate how milk fat affected consumer preferences for fluid milk. Threshold tests were conducted to determine the JND for each reference milk (skim, 1%, 2%, and whole milk), with a minimum of 60 consumers for each JND. The JND was determined for milks by visual appearance without tasting and tasting without visual cues. Serving temperature effect (4, 8, or 15°C) on tasting JND values were also investigated. The established JND values were then used to conduct ascending forced-choice preference tests with milks. Consumers were assigned to 3 groups based on self-reported milk consumption: skim milk drinkers (n = 59), low-fat milk drinkers (consumed 1% or 2% milk, n = 64), and whole milk drinkers (n = 49). Follow-up interviews were conducted where consumers were asked to taste and explain their preference between milks that showed the most polarization within each consumer segment. Descriptive sensory analysis was performed on the milks used in the follow-up interviews to quantify sensory differences. Visual-only JND were lower than tasting-only JND values. Preference testing revealed 3 distinct preference curves among the consumer segments. Skim milk drinkers preferred skim milk and up to 2% milk fat, but disliked milk higher in fat due to it being "too thick," "too heavy," "flavor and texture like cream," "too fatty," and "looks like half and half." Low-fat milk drinkers preferred 2% milk up to 3.25% (whole milk), but then disliked higher milk fat content. Whole milk drinkers preferred whichever milk was higher in milk fat regardless of how high the fat content was, distinct from skim and low-fat milk drinkers. The findings of this study provide insights on sensory characteristics of milk fat in fluid milk and consumer sensory perception of these properties. These results also provide insights on how the industry might adjust milk fat references for adjusting milk sensory properties to increase milk preference and remain within the standards of identity of milk. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Investigating the role of radixin in modulation of stereocilia length and stiffness

NASA Astrophysics Data System (ADS)

Prasad, Sonal; Fridberger, Anders

2018-05-01

Mammalian hearing depends on deflection of stereocilia on the sensory outer hair cells of the inner ear. Previous data indicate that the stiffness of outer hair cell stereocilia are actively regulated. The molecular mechanism that regulate the deflection of stereocilia are presently less known. The aim of the study is to investigate the mechanistic pathway that underlie the stiffness modulation of outer hair cell stereocilia. Our hypothesis is that the membrane-cytoskeleton linker protein radixin, which is present at high concentration in stereocilia, could contribute to stiffness regulation. To test this hypothesis, we use the radixin blocker DX-52-1 which binds strongly and specifically to radixin. Time-resolved confocal imaging was used to visualize the sound-evoked motion of stereocilia in a semi-intact preparation of the guinea pig temporal bone. Cochlear microphonic potentials were also measured, using electrodes positioned in scala media. We found that the DX-52-1 inhibitor leads to an increase in stereocilia movements and decline in the amplitude of the cochlear microphonic potential. However, DX-52-1 caused a paradoxical increase in electromotility. These results suggest that radixin has a functionally important regulatory role in the mature inner ear.

Expedient range enhanced 3-D robot colour vision

NASA Astrophysics Data System (ADS)

Jarvis, R. A.

1983-01-01

Computer vision has been chosen, in many cases, as offering the richest form of sensory information which can be utilized for guiding robotic manipulation. The present investigation is concerned with the problem of three-dimensional (3D) visual interpretation of colored objects in support of robotic manipulation of those objects with a minimum of semantic guidance. The scene 'interpretations' are aimed at providing basic parameters to guide robotic manipulation rather than to provide humans with a detailed description of what the scene 'means'. Attention is given to overall system configuration, hue transforms, a connectivity analysis, plan/elevation segmentations, range scanners, elevation/range segmentation, higher level structure, eye in hand research, and aspects of array and video stream processing.

Message strategies in direct-to-consumer pharmaceutical advertising: a content analysis using Taylor's six-segment message strategy wheel.

PubMed

Tsai, Wan-Hsiu Sunny; Lancaster, Alyse R

2012-01-01

This exploratory study applies Taylor's (1999) six-segment message strategy wheel to direct-to-consumer (DTC) pharmaceutical television commercials to understand message strategies adopted by pharmaceutical advertisers to persuade consumers. A convenience sample of 96 DTC commercial campaigns was analyzed. The results suggest that most DTC drug ads used a combination approach, providing consumers with medical and drug information while simultaneously appealing to the viewer's ego-related needs and desires. In contrast to ration and ego strategies, other approaches including routine, acute need, and social are relatively uncommon while sensory was the least common message strategy. Findings thus recognized the educational value of DTC commercials.

Outer Retinal Tubulation in Advanced Age-Related Macular Degeneration: Optical Coherence Tomographic Findings Correspond to Histology

PubMed Central

Schaal, Karen B.; Freund, K. Bailey; Litts, Katie M.; Zhang, Yuhua; Messinger, Jeffrey D.; Curcio, Christine A.

2014-01-01

Purpose To compare optical coherence tomography (OCT) and histology of outer retinal tubulation (ORT) secondary to advanced age-related macular degeneration (AMD) in patients and in post-mortem specimens, with particular attention to the basis of the hyper-reflective border of ORT. Method A private referral practice (imaging) and an academic research laboratory (histology) collaborated on two retrospective case series. High-resolution OCT raster scans of 43 eyes (34 patients) manifesting ORT secondary to advanced AMD were compared to high-resolution histological sections through the fovea and superior perifovea of donor eyes (13 atrophic AMD and 40 neovascular AMD) preserved ≤4 hours after death. Results ORT seen on OCT corresponded to histologic findings of tubular structures comprised largely of cones lacking outer segments (OS) and lacking inner segments (IS). Four phases of cone degeneration were histologically distinguishable in ORT lumenal walls, nascent, mature, degenerate, and end-stage (IS and OS; IS only; no IS; no photoreceptors and only Müller cells forming external limiting membrane, ELM, respectively). Mitochondria, which are normally long and bundled within IS ellipsoids, were small and scattered within shrunken IS and cell bodies of surviving cones. A lumenal border was delimited by an ELM. ORT observed in closed and open configurations were distinguishable from cysts and photoreceptor islands on both OCT and histology. Hyper-reflective lumenal material seen on OCT represents trapped retinal pigment epithelium (RPE) and non-RPE cells. Conclusions The defining OCT features of ORT are location in the outer nuclear layer (ONL), a hyper-reflective band differentiating it from cysts, and RPE that is either dysmorphic or absent. ORT histologic and OCT findings corresponded in regard to composition, location, shape, and stages of formation. The reflectivity of ORT lumenal walls on OCT apparently does not require an OS or an IS/OS junction, indicating an independent reflectivity source, possibly mitochondria, in the IS. PMID:25635579

Outer Retinal Changes Including the Ellipsoid Zone Band in Usher Syndrome 1B due to MYO7A Mutations.

PubMed

Sumaroka, Alexander; Matsui, Rodrigo; Cideciyan, Artur V; McGuigan, David B; Sheplock, Rebecca; Schwartz, Sharon B; Jacobson, Samuel G

2016-07-01

To study transition zones from normal to abnormal retina in Usher syndrome IB (USH1B) caused by myosin 7A (MYO7A) mutations. Optical coherence tomography (OCT) scattering layers in outer retina were segmented in patients (n = 16, ages 2-42; eight patients had serial data, average interval 4.5 years) to quantify outer nuclear layer (ONL) and outer segments (OS) as well as the locus of EZ (ellipsoid zone) edge and its extent from the fovea. Static perimetry was measured under dark-adapted (DA) and light-adapted (LA) conditions. Ellipsoid zone edge in USH1B-MYO7A could be located up to 23° from the fovea. Ellipsoid zone extent constricted at a rate of 0.51°/year with slower rates at smaller eccentricities. A well-defined EZ line could be associated with normal or abnormal ONL and/or OS thickness; detectable ONL extended well beyond EZ edge. At the EZ edge, the local slope of LA sensitivity loss was 2.6 (±1.7) dB/deg for central transition zones. At greater eccentricities, the local slope of cone sensitivity loss was shallower (1.1 ± 0.4 dB/deg for LA) than that of rod sensitivity loss (2.8 ± 1.2 dB/deg for DA). In USH1B-MYO7A, constriction rate of EZ extent depends on the initial eccentricity of the transition. Ellipsoid zone edges in the macula correspond to large local changes in cone vision, but extramacular EZ edges show more pronounced losses on rod-based vision tests. It is advisable to use not only the EZ line but also other structural and functional parameters for estimating natural history of disease and possible therapeutic effects in future clinical trials of USH1B-MYO7A.

Surgical Treatment of Laser Induced Eye Injuries

DTIC Science & Technology

1990-12-05

Continue on reverse if necessary and identify by block number) Subretinal blood within the macula may play a causative role in visual loss in a...period. Initial observations included clot organization with retraction of fibrin strands tearing photoreceptor outer segments. Later degeneration ...macular degeneration is the leading cause of permanent blindness in people over age 60 in the industrialized world’. Subretinal hemorrhage from

Noise Enhanced Sensory Signal Processing

DTIC Science & Technology

2012-01-31

Moreover, a contrast sensitivity function (CSF), as an object feature enhancer , was employed for further improving the segmentation performance, which...Digital mammography work appeared in ACM Tech News on Feb. 3, 2010. 8. Interactions/Transitions Invited talks: • P.K. Varshney, “Noise Enhanced ... mammography machines with regard to our work on image enhancement based on SR. • Lectures at Lockheed Martin in Syracuse and SRC that included discussion

Oil-spill risk analysis: Cook inlet outer continental shelf lease sale 149. Volume 1. The analysis. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, W.R.; Marshall, C.F.; Anderson, C.M.

1994-08-01

This report summarizes results of an oil-spill risk analysis (OSRA) conducted for the proposed lower Cook Inlet Outer Continental Shelf (OCS) Lease Sale 149. The objective of this analysis was to estimate relative oil-spill risks associated with oil and gas production from the leasing alternatives proposed for the lease sale. The Minerals Management Service (MMS) will consider the analysis in the environmental impact statement (EIS) prepared for the lease sale. The analysis for proposed OCS Lease Sale 149 was conducted in three parts corresponding to different aspects of the overall problem. The first part dealt with the probability of oil-spillmore » occurrence. The second dealt with trajectories of oil spills from potential spill sites to various environmental resources or land segments. The third part combined the results of the first two parts to give estimates of the overall oil-spill risk if there is oil production as a result of the lease sale. To aid the analysis, conditional risk contour maps of seasonal conditional probabilities of spill contact were generated for each environmental resource or land segment in the study area (see vol. 2).« less

Exploration of the pore structure of a peptide-gated Na+channel

PubMed Central

Poët, Mallorie; Tauc, Michel; Lingueglia, Eric; Cance, Peggy; Poujeol, Philippe; Lazdunski, Michel; Counillon, Laurent

2001-01-01

The FMRF-amide-activated sodium channel (FaNaC), a member of the ENaC/Degenerin family, is a homotetramer, each subunit containing two transmembrane segments. We changed independently every residue of the first transmembrane segment (TM1) into a cysteine and tested each position’s accessibility to the cysteine covalent reagents MTSET and MTSES. Eleven mutants were accessible to the cationic MTSET, showing that TM1 faces the ion translocation pathway. This was confirmed by the accessibility of cysteines present in the acid-sensing ion channels and other mutations introduced in FaNaC TM1. Modification of accessibilities for positions 69, 71 and 72 in the open state shows that the gating mechanism consists of the opening of a constriction close to the intracellular side. The anionic MTSES did not penetrate into the channel, indicating the presence of a charge selectivity filter in the outer vestibule. Furthermore, amiloride inhibition resulted in the channel occlusion in the middle of the pore. Summarizing, the ionic pore of FaNaC includes a large aqueous cavity, with a charge selectivity filter in the outer vestibule and the gate close to the interior. PMID:11598003

A distance measurement between specific sites on the cytoplasmic surface of bovine rhodopsin in rod outer segment disk membranes.

PubMed

Albert, A D; Watts, A; Spooner, P; Groebner, G; Young, J; Yeagle, P L

1997-08-14

Structural information on mammalian integral membrane proteins is scarce. As part of work on an alternative approach to the structure of bovine rhodopsin, a method was devised to obtain an intramolecular distance between two specific sites on rhodopsin while in the rod outer segment disk membrane. In this report, the distance between the rhodopsin kinase phosphorylation site(s) on the carboxyl terminal and the top of the third transmembrane helix was measured on native rhodopsin. Rhodopsin was labeled with a nuclear spin label (31P) by limited phosphorylation with rhodopsin kinase. Major phosphorylation occurs at serines 343 and 338 on the carboxyl terminal. The phosphorylated rhodopsin was then specifically labeled on cysteine 140 with an electron spin label. Magic angle spinning 31P-nuclear magnetic resonance revealed the resonance arising from the phosphorylated protein. The enhancement of the transverse relaxation of this resonance by the paramagnetic spin label was observed. The strength of this perturbation was used to determine the through-space distance between the phosphorylation site(s) and the spin label position. A distance of 18 +/- 3 A was obtained.

Outer segment phagocytosis by cultured retinal pigment epithelial cells requires Gas6.

PubMed

Hall, M O; Prieto, A L; Obin, M S; Abrams, T A; Burgess, B L; Heeb, M J; Agnew, B J

2001-10-01

The function and viability of vertebrate photoreceptors requires the daily phagocytosis of photoreceptor outer segments (OS) by the adjacent retinal pigment epithelium (RPE). We demonstrate here a critical role in this process for Gas6 and by implication one of its receptor protein tyrosine kinases (RTKs), Mertk (Mer). Gas6 specifically and selectively stimulates the phagocytosis of OS by normal cultured rat RPE cells. The magnitude of the response is dose-dependent and shows an absolute requirement for calcium. By contrast the Royal College of Surgeons (RCS) rat RPE cells, in which a mutation in the gene Mertk results in the expression of a truncated, non-functional receptor, does not respond to Gas6. These data strongly suggest that activation of Mertk by its ligand, Gas6, is the specific signaling pathway responsible for initiating the ingestion of shed OS. Moreover, photoreceptor degeneration in the RCS rat retina, which lacks Mertk, and in humans with a mutation in Mertk, strongly suggests that the Gas6/Mertk signaling pathway is essential for photoreceptor viability. We believe that this is the first demonstration of a specific function for Gas6 in the eye. Copyright 2001 Academic Press.

Inner and outer segment junction (IS/OS line) integrity in ocular Behçet's disease.

PubMed

Yüksel, Harun; Türkcü, Fatih M; Sahin, Muhammed; Cinar, Yasin; Cingü, Abdullah K; Ozkurt, Zeynep; Sahin, Alparslan; Ari, Seyhmus; Caça, Ihsan

2014-08-01

In this study, we examined the spectral domain optical coherence tomography (OCT) findings of ocular Behçet's disease (OB) in patients with inactive uveitis. Specifically, we analyzed the inner and outer segment junction (IS/OS line) integrity and the effect of disturbed IS/OS line integrity on visual acuity. Patient files and OCT images of OB patients who had been followed-up between January and June of the year 2013 at the Dicle University Eye Clinic were evaluated retrospectively. Sixty-six eyes of 39 patients were included the study. OCT examination of the patients with inactive OB revealed that approximately 25% of the patients had disturbed IS/OS and external limiting membrane (EML) line integrity, lower visual acuity (VA), and lower macular thickness than others. Linear regression analysis revealed that macular thickness was not an independent variable for VA. In contrast, the IS/OS line integrity was an independent variable for VA in inactive OB patients. In this study, we showed that the IS/OS line integrity was an independent variable for VA in inactive OB patients. Further prospective studies are needed to evaluate the integrity of the IS/OS line in OB patients.

Type 3 Neovascularization Associated with Retinitis Pigmentosa.

PubMed

Sayadi, Jihene; Miere, Alexandra; Souied, Eric H; Cohen, Salomon Y

2017-01-01

To report a case of type 3 neovascular lesion in a patient with retinitis pigmentosa (RP) complicated by macular edema. A 78-year-old man with a long follow-up for RP was referred for painless visual acuity decrease in the right eye. Best-corrected visual acuity was 20/125 in the right eye and 20/40 in the left. Fundus examination showed typical RP and macular edema in both eyes. In the right eye, spectral domain optical coherence tomography revealed a marked cystic macular edema associated with disruption of the Bruch membrane/retinal pigment epithelium complex overlying a pigmentary epithelium detachment, with a vascular structure which appeared to originate from the deep capillary plexus and to be connected with the subretinal pigment epithelium space. Optical coherence tomography angiography showed a high-flow vessel infiltrating the outer retinal layers in the deep capillary plexus segmentation, and a tuft-shaped, bright, high-flow network that seemed to be connected with the subretinal pigment epithelium space in the outer retinal layer segmentation. This presentation was consistent with an early type 3 neovascular lesion in the right eye. Type 3 neovascularization may be considered a possible complication of RP.

A key role for cyclic nucleotide gated (CNG) channels in cGMP-related retinitis pigmentosa.

PubMed

Paquet-Durand, François; Beck, Susanne; Michalakis, Stylianos; Goldmann, Tobias; Huber, Gesine; Mühlfriedel, Regine; Trifunović, Dragana; Fischer, M Dominik; Fahl, Edda; Duetsch, Gabriele; Becirovic, Elvir; Wolfrum, Uwe; van Veen, Theo; Biel, Martin; Tanimoto, Naoyuki; Seeliger, Mathias W

2011-03-01

The rd1 natural mutant is one of the first and probably the most commonly studied mouse model for retinitis pigmentosa (RP), a severe and frequently blinding human retinal degeneration. In several decades of research, the link between the increase in photoreceptor cGMP levels and the extremely rapid cell death gave rise to a number of hypotheses. Here, we provide clear evidence that the presence of cyclic nucleotide gated (CNG) channels in the outer segment membrane is the key to rod photoreceptor loss. In Cngb1(-/-) × rd1 double mutants devoid of regular CNG channels, cGMP levels are still pathologically high, but rod photoreceptor viability and outer segment morphology are greatly improved. Importantly, cone photoreceptors, the basis for high-resolution daylight and colour vision, survived and remained functional for extended periods of time. These findings strongly support the hypothesis of deleterious calcium (Ca(2+))-influx as the cause of rapid rod cell death and highlight the importance of CNG channels in this process. Furthermore, our findings suggest that targeting rod CNG channels, rather than general Ca(2+)-channel blockade, is a most promising symptomatic approach to treat otherwise incurable forms of cGMP-related RP.

Clinical characteristics of occult macular dystrophy in family with mutation of RP1l1 gene.

PubMed

Tsunoda, Kazushige; Usui, Tomoaki; Hatase, Tetsuhisa; Yamai, Satoshi; Fujinami, Kaoru; Hanazono, Gen; Shinoda, Kei; Ohde, Hisao; Akahori, Masakazu; Iwata, Takeshi; Miyake, Yozo

2012-06-01

To report the clinical characteristics of occult macular dystrophy (OMD) in members of one family with a mutation of the RP1L1 gene. Fourteen members with a p.Arg45Trp mutation in the RP1L1 gene were examined. The visual acuity, visual fields, fundus photographs, fluorescein angiograms, full-field electroretinograms, multifocal electroretinograms, and optical coherence tomographic images were examined. The clinical symptoms and signs and course of the disease were documented. All the members with the RP1L1 mutation except one woman had ocular symptoms and signs of OMD. The fundus was normal in all the patients during the entire follow-up period except in one patient with diabetic retinopathy. Optical coherence tomography detected the early morphologic abnormalities both in the photoreceptor inner/outer segment line and cone outer segment tip line. However, the multifocal electroretinograms were more reliable in detecting minimal macular dysfunction at an early stage of OMD. The abnormalities in the multifocal electroretinograms and optical coherence tomography observed in the OMD patients of different durations strongly support the contribution of RP1L1 mutation to the presence of this disease.

Antinociceptive effect of vinpocetine--a comprehensive survey.

PubMed

Csillik, Bertalan; Mihály, András; Knyihár-Csillik, Elizabeth

2010-05-30

Blockade of retrograde transport of nerve growth factor (NGF) in a peripheral sensory nerve is known to induce transganglionic degenerative atrophy (TDA) of central sensory terminals in the upper dorsal horn of the related, ipsilateral segments(s) of the spinal cord. The ensuing temporary blockade of transmission of nociceptive impulses has been utilized in the therapy of intractable pain, using transcutaneous iontophoresis of the microtubule inhibitors vincristin and vinblastin, drugs which inhibit retrograde transport of NGF. Since microtubule inhibition might inhibit (at least theoretically) mitotic processes in general, we sought to find a drug which inhibits retrograde transport of NGF without microtubule inhibition. Vinpocetine, a derivate of vincamine, which does not interfere with microtubular function, was found to inhibit retrograde axoplasmic transport of NGF in peripheral sensory nerves, similarly to vincristin and vinblastin. Blockade of NGF transport is followed by transganglionic degenerative atrophy in the segmentally related, ipsilateral superficial spinal dorsal horn, characterized by depletion of the marker enzymes of nociception, fluoride resistant acid phosphatase (FRAP) and thiamine monophosphatase (TMP) from the Rolando substance and by decrease of the pain-related neuropeptides substance P (SP) and calcitonin gene-related peptide (CGRP) from lamina I-II-III. Based upon these findings, it has been suggested that vinpocetine may result in a locally restricted decrease of nociception. Herewith, the structural and behavioral effects of perineurally administered vinpocetine are discussed. Nociception, induced by intraplantar injection of formalin, was mitigated by perineural application of vinpocetine; also formalin-induced expression of c-fos in the ipsilateral, segmentally related superficial dorsal horn, was prevented by this treatment. Since vinpocetine is not a microtubule inhibitor, its mode of action is enigmatic. It is assumed that the effect of vinpocetine might be related to interaction with membrane-trafficking proteins, such as signalling endosomes and the endocytosis-mediating "pincher" protein, involved in retrograde axoplasmic transport of NGF, or to interaction with glial elements, recently reported to be involved in the modulation of pain in the spinal cord. Based on animal experiments it is assumed that the temporary, locally restricted decrease of nociception, induced by vinpocetine applied via transcutaneous iontophoresis, might open up new avenues in the clinical treatment of intractable pain.

Organic and conventional nonflavored yogurts from the Italian market: study on sensory profiles and consumer acceptability.

PubMed

Toschi, Tullia Gallina; Bendini, Alessandra; Barbieri, Sara; Valli, Enrico; Cezanne, Marie Louise; Buchecker, Kirsten; Canavari, Maurizio

2012-11-01

The sensory properties of food products are an important success factor, especially in the organic market, where many producers and distributors of organic food claim superior taste for their products compared to the conventional alternative. For this reason consumer expectations and preferences, as well as the sensory properties of conventional and organic yogurt, have to be investigated in depth. In this work, the sensory profiling and consumer data of six nonflavored organic and conventional Italian yogurts were elaborated. Some results on the data segmentation (heavy and light users of organic food) and on the effect of information on liking (blind and labeled test) were obtained. Multivariate analysis was carried out to study how the sensory characteristics of 'natural yogurts' drive consumer liking. Consumers' preferences were oriented towards a creamy mouthfeel and smooth visual appearance and for a less acid and fresh taste. In particular, a conventional yogurt was the least accepted, because it was not creamy enough. This paper shows there is room to improve unflavored yogurt to better meet consumer expectations. Sensory profiling did not allow a distinction in odor/taste/texture between organic and conventional samples. However, three of four organic samples were in the region of highest consumer acceptability, fitting well consumers' preference. There was no clear tendency that heavy or light users scored differently in the blind and labeled tests regarding overall liking but, for all, the most liked conventional yogurt scored higher when labeled as organic. Copyright © 2012 Society of Chemical Industry.

Structure and Sensilla of the Mouthparts of the Spotted Lanternfly Lycorma delicatula (Hemiptera: Fulgoromorpha: Fulgoridae), a Polyphagous Invasive Planthopper

PubMed Central

Hao, Yanan; Dietrich, Christopher H.; Dai, Wu

2016-01-01

Mouthparts are among the most important sensory and feeding structures in insects and comparative morphological study may help explain differences in feeding behavior and diet breadth among species. The spotted lanternfly Lycorma delicatula (White) (Hemiptera: Fulgoromorpha: Fulgoridae) is a polyphagous agricultural pest originating in China, recently established and becoming widespread in Korea, and more recently introduced into eastern North America. It causes severe economic damage by sucking phloem sap and the sugary excrement produced by nymphs and adults serves as a medium for sooty mold. To facilitate future study of feeding mechanisms in this insect, the fine-structural morphology of mouthparts focusing on the distribution of sensilla located on the labium in adult L. delicatula was observed using a scanning electron microscope. The mouthparts consist of a small cone-shaped labrum, a tubular labium and a stylet fascicle consisting of two inner interlocked maxillary stylets partially surrounded by two shorter mandibular stylets similar to those found in other hemipteran insects. The five-segmented labium is unusual (most other Fulgoromorpha have four segments) and is provided with several types of sensilla and cuticular processes situated on the apex of its distal labial segment. In general, nine types of sensilla were found on the mouthparts. Six types of sensilla and four types of cuticular processes are present on sensory fields of the labial apex. The proposed taxonomic and functional significance of the sensilla are discussed. Morphological similarities in the interlocking mechanism of the stylets suggest a relationship between Fulgoromorpha and Heteroptera. PMID:27253390

Clinical and Demographic Characteristics Related to Onset

PubMed Central

Norris, Scott A; Jinnah, H A; Espay, Alberto J.; Klein, Christine; Brüggemann, Norbert; Barbano, Richard L.; Malaty, Irene; Rodriguez, Ramon L.; Vidailhet, Marie; Roze, Emmanuel; Reich, Stephen G.; Berman, Brian D.; LeDoux, Mark S.; Richardson, Sarah Pirio; Agarwal, Pinky; Mari, Zoltan; Ondo, William; Shih, Ludy C; Fox, Susan; Berardelli, Alfredo; Testa, Claudia M; Chang, Florence CF; Troung, Daniel; Nahab, Fatta; Xie, Tao; Hallett, Mark; Rosen, Ami R; Wright, Laura J; Perlmutter, JS

2016-01-01

Background Clinical characteristics of isolated, idiopathic cervical dystonia such as onset site and spread to and from additional body regions have been addressed in single-site studies with limited data and incomplete or variable dissociation of focal and segmental subtypes. Objectives To characterize clinical characteristics and demographics of isolated, idiopathic cervical dystonia in the largest standardized, multicenter cohort. Methods The Dystonia Coalition, through a consortium of 37 recruiting sites in North America, Europe and Australia recruited 1477 participants with focal (60.7%) or segmental (39.3%) cervical dystonia on examination. Clinical and demographic characteristics were evaluated in terms of the body region of dystonia onset and spread. Results Site of dystonia onset was: a) focal neck only (78.5%), b) focal onset elsewhere with later segmental spread to neck (13.3%), and c) segmental onset with initial neck involvement (8.2%).Frequency of spread from focal cervical to segmental dystonia (22.8%) was consistent with prior reports, but frequency of segmental onset with initial neck involvement was substantially higher than 3% previously reported. Cervical dystonia with focal neck onset, more than other subtypes, is associated with spread and tremor of any type. Sensory tricks were less frequent in cervical dystonia with segmental components, and segmental cervical onset occurred at an older age. Conclusions Subgroups had modest but significant differences in the clinical characteristics that may represent different clinical entities or pathophysiologic subtypes. These findings are critical for design and implementation of studies to describe, treat, or modify disease progression in idiopathic isolated cervical dystonia. PMID:27753188

Differentiation of Swine iPSC into Rod Photoreceptors and Their Integration into the Retina

PubMed Central

Zhou, Liang; Wang, Wei; Liu, Yongqing; de Castro, Juan Fernandez; Ezashi, Toshihiko; Telugu, Bhanu Prakash V.L.; Roberts, R. Michael; Kaplan, Henry J.; Dean, Douglas C.

2014-01-01

Absence of a regenerative pathway for damaged retina following injury or disease has led to experiments utilizing stem cell transplantation for retinal repair, and encouraging results have been obtained in rodents. The swine eye is a closer anatomical and physiological match to the human eye, but embryonic stem cells have not been isolated from pig, and photoreceptor differentiation has not been demonstrated with swine induced pluripotent stem cells (iPSC). Here, we subjected swine iPSC to a rod photoreceptor differentiation protocol consisting of floating culture as embryoid bodies followed by differentiation in adherent culture. Real time PCR and immunostaining of differentiated cells demonstrated loss of expression of the pluripotent genes POU5F1, NANOG and SOX2 and induction of rod photoreceptor genes RCVRN, NRL, RHO and ROM1. While these differentiated cells displayed neuronal morphology, culturing on a Matrigel substratum triggered a further morphological change resulting in concentration of RHO and ROM1 in outer segment-like projections resembling those on primary cultures of rod photoreceptors. The differentiated cells were transplanted into the subretinal space of pigs treated with iodoacetic acid to eliminate rod photoreceptors. Three weeks after transplantation, engrafted RHO+ cells were evident in the outer nuclear layer where photoreceptors normally reside. A portion of these transplanted cells had generated projections resembling outer segments. These results demonstrate that swine iPSC can differentiate into photoreceptors in culture and these cells can integrate into the damaged swine neural retina thus laying a foundation for future studies using the pig as a model for retinal stem cell transplantation. PMID:21491544

Model-based segmentation of the facial nerve and chorda tympani in pediatric CT scans

NASA Astrophysics Data System (ADS)

Reda, Fitsum A.; Noble, Jack H.; Rivas, Alejandro; Labadie, Robert F.; Dawant, Benoit M.

2011-03-01

In image-guided cochlear implant surgery an electrode array is implanted in the cochlea to treat hearing loss. Access to the cochlea is achieved by drilling from the outer skull to the cochlea through the facial recess, a region bounded by the facial nerve and the chorda tympani. To exploit existing methods for computing automatically safe drilling trajectories, the facial nerve and chorda tympani need to be segmented. The effectiveness of traditional segmentation approaches to achieve this is severely limited because the facial nerve and chorda are small structures (~1 mm and ~0.3 mm in diameter, respectively) and exhibit poor image contrast. We have recently proposed a technique to achieve this task in adult patients, which relies on statistical models of the structures. These models contain intensity and shape information along the central axes of both structures. In this work we use the same method to segment pediatric scans. We show that substantial differences exist between the anatomy of children and the anatomy of adults, which lead to poor segmentation results when an adult model is used to segment a pediatric volume. We have built a new model for pediatric cases and we have applied it to ten scans. A leave-one-out validation experiment was conducted in which manually segmented structures were compared to automatically segmented structures. The maximum segmentation error was 1 mm. This result indicates that accurate segmentation of the facial nerve and chorda in pediatric scans is achievable, thus suggesting that safe drilling trajectories can also be computed automatically.

An animal model for Norrie disease (ND): gene targeting of the mouse ND gene.

PubMed

Berger, W; van de Pol, D; Bächner, D; Oerlemans, F; Winkens, H; Hameister, H; Wieringa, B; Hendriks, W; Ropers, H H

1996-01-01

In order to elucidate the cellular and molecular processes which are involved in Norrie disease (ND), we have used gene targeting technology to generate ND mutant mice. The murine homologue of the ND gene was cloned and shown to encode a polypeptide that shares 94% of the amino acid sequence with its human counterpart. RNA in situ hybridization revealed expression in retina, brain and the olfactory bulb and epithelium of 2 week old mice. Hemizygous mice carrying a replacement mutation in exon 2 of the ND gene developed retrolental structures in the vitreous body and showed an overall disorganization of the retinal ganglion cell layer. The outer plexiform layer disappears occasionally, resulting in a juxtaposed inner and outer nuclear layer. At the same regions, the outer segments of the photoreceptor cell layer are no longer present. These ocular findings are consistent with observations in ND patients and the generated mouse line provides a faithful model for study of early pathogenic events in this severe X-linked recessive neurological disorder.

Head patterning and Hox gene expression in an onychophoran and its implications for the arthropod head problem.

PubMed

Eriksson, Bo Joakim; Tait, Noel N; Budd, Graham E; Janssen, Ralf; Akam, Michael

2010-09-01

The arthropod head problem has puzzled zoologists for more than a century. The head of adult arthropods is a complex structure resulting from the modification, fusion and migration of an uncertain number of segments. In contrast, onychophorans, which are the probable sister group to the arthropods, have a rather simple head comprising three segments that are well defined during development, and give rise to the adult head with three pairs of appendages specialised for sensory and food capture/manipulative purposes. Based on the expression pattern of the anterior Hox genes labial, proboscipedia, Hox3 and Deformed, we show that the third of these onychophoran segments, bearing the slime papillae, can be correlated to the tritocerebrum, the most anterior Hox-expressing arthropod segment. This implies that both the onychophoran antennae and jaws are derived from a more anterior, Hox-free region corresponding to the proto and deutocerebrum of arthropods. Our data provide molecular support for the proposal that the onychophoran head possesses a well-developed appendage that corresponds to the anterior, apparently appendage-less region of the arthropod head.

[Pharmacology of local anesthetics and clinical aspects of segmental blocking. II. Spinal anesthesia].

PubMed

Kozlov, S P; Svetlov, V A; Luk'ianov, M V

1998-01-01

Clinical picture of development of segmental blocking after subarachnoidal injection of hyperbaric solutions of 0.75% bupivacaine, 5% ultracaine, and isobaric 0.5% bupivacaine is studied. A total of 152 patients operated on the lower part of the body and the lower limbs were examined under conditions of single, prolonged subarachnoidal, and combined spinal epidural anesthesia. Ultracaine and bupivacaine in different concentrations with different barism provided anesthesia equivalent by the efficacy, depth, and dissemination of sensory block. Segmental blocking with 5% ultracaine was characterized by the shortest latent period (3.14 +/- 0.16 min, p < 0.05) but was no shorter (124.1 +/- 3.37 min) than operative analgesia with 0.75% hyperbaric bupivacaine (120.0 +/- 5.10 min). Isobaric bupivacaine provided the longest effective analgesia (215.0 +/- 45.0 min, p < 0.05). Microcatheter technique improved the safety and control of subarachnoidal anesthesia in comparison with a single injection, and combined spinal epidural anesthesia shortened the latent period of segmental blocking and ensured intraoperative anesthesia and postoperative analgesia at the expense of the epidural component.

Brain anatomy of the marine tardigrade Actinarctus doryphorus (Arthrotardigrada).

PubMed

Persson, Dennis K; Halberg, Kenneth A; Jørgensen, Aslak; Møbjerg, Nadja; Kristensen, Reinhardt M

2014-02-01

Knowledge of tardigrade brain structure is important for resolving the phylogenetic relationships of Tardigrada. Here, we present new insight into the morphology of the brain in a marine arthrotardigrade, Actinarctus doryphorus, based on transmission electron microscopy, supported by scanning electron microscopy, conventional light microscopy as well as confocal laser scanning microscopy. Arthrotardigrades contain a large number of plesiomorphic characters and likely represent ancestral tardigrades. They often have segmented body outlines and each trunk segment, with its paired set of legs, may have up to five sensory appendages. Noticeably, the head carries numerous cephalic appendages that are structurally equivalent to the sensory appendages of the trunk segments. Our data reveal that the brain of A. doryphorus is partitioned into three paired lobes, and that these lobes exhibit a more pronounced separation as compared to that of eutardigrades. The first brain lobe in A. doryphorus is located anteriodorsally, with the second lobe just below it in an anterioventral position. Both of these two paired lobes are located anterior to the buccal tube. The third pair of brain lobes are situated posterioventrally to the first two lobes, and flank the buccal tube. In addition, A. doryphorus possesses a subpharyngeal ganglion, which is connected with the first of the four ventral trunk ganglia. The first and second brain lobes in A. doryphorus innervate the clavae and cirri of the head. The innervations of these structures indicate a homology between, respectively, the clavae and cirri of A. doryphorus and the temporalia and papilla cephalica of eutardigrades. The third brain lobes innervate the buccal lamella and the stylets as described for eutardigrades. Collectively, these findings suggest that the head region of extant tardigrades is the result of cephalization of multiple segments. Our results on the brain anatomy of Actinarctus doryphorus support the monophyly of Panarthropoda. Copyright © 2013 Wiley Periodicals, Inc.

An application of a vulnerability index to oil spill modeling in the Gulf of Mexico

USGS Publications Warehouse

LaBelle, R.P.; Rainey, Gail; Lanfear, K.J.

1982-01-01

An analysis was made of the relative impact to the shoreline of the Gulf of Mexico from proposed Federal Outer Continental Shelf oil and gas leasing activity. An oil spill trajectory model was coupled with a land segment vulnerability characterization to predict the risks to the shoreline. Such a technique allows spatial and temporal variability in oil spill sensitivity to be represented and combined with the likelihood of oil spill contact to specific coastal segments in the study area. Predicted relative impact was greatest along the coastlines of Louisiana, Mississippi, and Alabama. Useful information is provided for environmental impact analysis, as well as oil spill response planning.

Ceramic Cerami Turbine Nozzle

DOEpatents

Boyd, Gary L.

1997-04-01

A turbine nozzle vane assembly having a preestablished rate of thermal expansion is positioned in a gas turbine engine and being attached to conventional metallic components. The metallic components having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the turbine nozzle vane assembly. The turbine nozzle vane assembly includes an outer shroud and an inner shroud having a plurality of horizontally segmented vanes therebetween being positioned by a connecting member positioning segmented vanes in functional relationship one to another. The turbine nozzle vane assembly provides an economical, reliable and effective ceramic component having a preestablished rate of thermal expansion being greater than the preestablished rate of thermal expansion of the other component.

Displacement coefficients along the inner boundaries of radially cracked ring segments subject to forces and couples

NASA Technical Reports Server (NTRS)

Gross, B.

1977-01-01

Displacement results of plane boundary collocation analysis are given for various locations on the inner boundaries of radially cracked ring segments (C-shaped specimens) subject to two complementary types of loading. Results are presented for ratios of outer to inner radius R sub o/R sub i in the range of 1.1 to 2.5, and ratios a/W in the range 0.1 to 0.8 where a is the crack length for a specimen of wall thickness W. By combination of these results the resultant displacement coefficient delta or the corresponding influence coefficient, can be obtained for any practical load line location of a pin loaded specimen.

Transition duct system with arcuate ceramic liner for delivering hot-temperature gases in a combustion turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include an arcuate connecting segment (36). An arcuate ceramic liner (60) may be inwardly disposed onto a metal outer shell (38) along the arcuate connecting segment of the exit piece. Structural arrangements are provided to securely attach the ceramic liner in the presence of substantial flow path pressurization. Cost-effective serviceability of the transition duct systems is realizable since the liner can be readily removed andmore » replaced as needed.« less

AKAP localizes in a specific subset of TRPV1 and CaV1.2 positive nociceptive rat DRG neurons

PubMed Central

Brandao, Katherine E.; Dell’Acqua, Mark L.; Levinson, Simon R.

2016-01-01

Modulation of phosphorylation states of ion channels is a critical step in the development of hyperalgesia during inflammation. Modulatory enhancement of channel activity may increase neuronal excitability and affect downstream targets such as gene transcription. The specificity required for such regulation of ion channels quickly occurs via targeting of protein kinases and phosphatases by the scaffolding A-kinase anchoring protein 79/150 (AKAP79/150). AKAP79/150 has been implicated in inflammatory pain by targeting PKA and PKC to the TRPV1 channel in peripheral sensory neurons, thus lowering threshold for activation by multiple inflammatory reagents. However, the expression pattern of AKAP79/150 in peripheral sensory neurons is unknown. In this study we use immunofluorescence microscopy to identify in DRG sections the peripheral neuron subtypes that express the rodent isoform AKAP150, as well as the subcellular distribution of AKAP150 and its potential target ion channels. We found that AKAP150 is predominantly expressed in a subset of small DRG sensory neurons where it is localized at the plasma membrane of the soma, axon initial segment and small fibers. The majority of these neurons is peripherin positive and produces c-fibers, though a small portion produces Aδ-fibers. Furthermore, we demonstrate that AKAP79/150 colocalizes with TRPV1 and CaV1.2 in the soma and axon initial segment. Thus AKAP150 is expressed in small, nociceptive DRG neurons where it is targeted to membrane regions and where it may play a role in the modulation of ion channel phosphorylation states required for hyperalgesia. PMID:21674494

Three-dimensional choroidal segmentation in spectral OCT volumes using optic disc prior information

NASA Astrophysics Data System (ADS)

Hu, Zhihong; Girkin, Christopher A.; Hariri, Amirhossein; Sadda, SriniVas R.

2016-03-01

Recently, much attention has been focused on determining the role of the peripapillary choroid - the layer between the outer retinal pigment epithelium (RPE)/Bruchs membrane (BM) and choroid-sclera (C-S) junction, whether primary or secondary in the pathogenesis of glaucoma. However, the automated choroidal segmentation in spectral-domain optical coherence tomography (SD-OCT) images of optic nerve head (ONH) has not been reported probably due to the fact that the presence of the BM opening (BMO, corresponding to the optic disc) can deflect the choroidal segmentation from its correct position. The purpose of this study is to develop a 3D graph-based approach to identify the 3D choroidal layer in ONH-centered SD-OCT images using the BMO prior information. More specifically, an initial 3D choroidal segmentation was first performed using the 3D graph search algorithm. Note that varying surface interaction constraints based on the choroidal morphological model were applied. To assist the choroidal segmentation, two other surfaces of internal limiting membrane and innerouter segment junction were also segmented. Based on the segmented layer between the RPE/BM and C-S junction, a 2D projection map was created. The BMO in the projection map was detected by a 2D graph search. The pre-defined BMO information was then incorporated into the surface interaction constraints of the 3D graph search to obtain more accurate choroidal segmentation. Twenty SD-OCT images from 20 healthy subjects were used. The mean differences of the choroidal borders between the algorithm and manual segmentation were at a sub-voxel level, indicating a high level segmentation accuracy.

Assembler: Efficient Discovery of Spatial Co-evolving Patterns in Massive Geo-sensory Data.

PubMed

Zhang, Chao; Zheng, Yu; Ma, Xiuli; Han, Jiawei

2015-08-01

Recent years have witnessed the wide proliferation of geo-sensory applications wherein a bundle of sensors are deployed at different locations to cooperatively monitor the target condition. Given massive geo-sensory data, we study the problem of mining spatial co-evolving patterns (SCPs), i.e ., groups of sensors that are spatially correlated and co-evolve frequently in their readings. SCP mining is of great importance to various real-world applications, yet it is challenging because (1) the truly interesting evolutions are often flooded by numerous trivial fluctuations in the geo-sensory time series; and (2) the pattern search space is extremely large due to the spatiotemporal combinatorial nature of SCP. In this paper, we propose a two-stage method called Assembler. In the first stage, Assembler filters trivial fluctuations using wavelet transform and detects frequent evolutions for individual sensors via a segment-and-group approach. In the second stage, Assembler generates SCPs by assembling the frequent evolutions of individual sensors. Leveraging the spatial constraint, it conceptually organizes all the SCPs into a novel structure called the SCP search tree, which facilitates the effective pruning of the search space to generate SCPs efficiently. Our experiments on both real and synthetic data sets show that Assembler is effective, efficient, and scalable.

SU-E-J-123: Assessing Segmentation Accuracy of Internal Volumes and Sub-Volumes in 4D PET/CT of Lung Tumors Using a Novel 3D Printed Phantom

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soultan, D; Murphy, J; James, C

2015-06-15

Purpose: To assess the accuracy of internal target volume (ITV) segmentation of lung tumors for treatment planning of simultaneous integrated boost (SIB) radiotherapy as seen in 4D PET/CT images, using a novel 3D-printed phantom. Methods: The insert mimics high PET tracer uptake in the core and 50% uptake in the periphery, by using a porous design at the periphery. A lung phantom with the insert was placed on a programmable moving platform. Seven breathing waveforms of ideal and patient-specific respiratory motion patterns were fed to the platform, and 4D PET/CT scans were acquired of each of them. CT images weremore » binned into 10 phases, and PET images were binned into 5 phases following the clinical protocol. Two scenarios were investigated for segmentation: a gate 30–70 window, and no gating. The radiation oncologist contoured the outer ITV of the porous insert with on CT images, while the internal void volume with 100% uptake was contoured on PET images for being indistinguishable from the outer volume in CT images. Segmented ITVs were compared to the expected volumes based on known target size and motion. Results: 3 ideal breathing patterns, 2 regular-breathing patient waveforms, and 2 irregular-breathing patient waveforms were used for this study. 18F-FDG was used as the PET tracer. The segmented ITVs from CT closely matched the expected motion for both no gating and gate 30–70 window, with disagreement of contoured ITV with respect to the expected volume not exceeding 13%. PET contours were seen to overestimate volumes in all the cases, up to more than 40%. Conclusion: 4DPET images of a novel 3D printed phantom designed to mimic different uptake values were obtained. 4DPET contours overestimated ITV volumes in all cases, while 4DCT contours matched expected ITV volume values. Investigation of the cause and effects of the discrepancies is undergoing.« less

Postembryonic development of the auditory system of the cicada Okanagana rimosa (Say) (Homoptera: Auchenorrhyncha: Cicadidae).

PubMed

Strauss, Johannes; Lakes-Harlan, Reinhard

2009-01-01

Cicadas (Homoptera: Auchenorrhyncha: Cicadidae) use acoustic signalling for mate attraction and perceive auditory signals by a tympanal organ in the second abdominal segment. The main structural features of the ear are the tympanum, the sensory organ consisting of numerous scolopidial cells, and the cuticular link between sensory neurones and tympanum (tympanal ridge and apodeme). Here, a first investigation of the postembryonic development of the auditory system is presented. In insects, sensory neurones usually differentiate during embryogenesis, and sound-perceiving structures form during postembryogenesis. Cicadas have an elongated and subterranian postembryogenesis which can take several years until the final moult. The neuroanatomy and functional morphology of the auditory system of the cicada Okanagana rimosa (Say) are documented for the adult and the three last larval stages. The sensory organ and the projection of sensory afferents to the CNS are present in the earliest stages investigated. The cuticular structures of the tympanum, the tympanal frame holding the tympanum, and the tympanal ridge differentiate in the later stages of postembryogenesis. Thus, despite the different life styles of larvae and adults, the neuronal components of the cicada auditory system develop already during embryogenesis or early postembryogenesis, and sound-perceiving structures like tympana are elaborated later in postembryogenesis. The life cycle allows comparison of cicada development to other hemimetabolous insects with respect to the influence of specially adapted life cycle stages on auditory maturation. The neuronal development of the auditory system conforms to the timing in other hemimetabolous insects.

Retinal Layer Abnormalities as Biomarkers of Schizophrenia.

PubMed

Samani, Niraj N; Proudlock, Frank A; Siram, Vasantha; Suraweera, Chathurie; Hutchinson, Claire; Nelson, Christopher P; Al-Uzri, Mohammed; Gottlob, Irene

2018-06-06

Schizophrenia is associated with several brain deficits, as well as visual processing deficits, but clinically useful biomarkers are elusive. We hypothesized that retinal layer changes, noninvasively visualized using spectral-domain optical coherence tomography (SD-OCT), may represent a possible "window" to these abnormalities. A Leica EnvisuTM SD-OCT device was used to obtain high-resolution central foveal B-scans in both eyes of 35 patients with schizophrenia and 50 demographically matched controls. Manual retinal layer segmentation was performed to acquire individual and combined layer thickness measurements in 3 macular regions. Contrast sensitivity was measured at 3 spatial frequencies in a subgroup of each cohort. Differences were compared using adjusted linear models and significantly different layer measures in patients underwent Spearman Rank correlations with contrast sensitivity, quantified symptoms severity, disease duration, and antipsychotic medication dose. Total retinal and photoreceptor complex thickness was reduced in all regions in patients (P < .0001). Segmentation revealed consistent thinning of the outer nuclear layer (P < .001) and inner segment layer (P < .05), as well as a pattern of parafoveal ganglion cell changes. Low spatial frequency contrast sensitivity was reduced in patients (P = .002) and correlated with temporal parafoveal ganglion cell complex thinning (R = .48, P = .01). Negative symptom severity was inversely correlated with foveal photoreceptor complex thickness (R = -.54, P = .001) and outer nuclear layer thickness (R = -.47, P = .005). Our novel findings demonstrate considerable retinal layer abnormalities in schizophrenia that are related to clinical features and visual function. With time, SD-OCT could provide easily-measurable biomarkers to facilitate clinical assessment and further our understanding of the disease.

Hybrid assistive systems for rehabilitation: lessons learned from functional electrical therapy in hemiplegics.

PubMed

Popović, Dejan B; Popović, Mirjana B

2006-01-01

This paper suggests that the optimal method for promoting of the recovery of upper extremity function in hemiplegic individuals is the use of hybrid assistive systems (HAS). The suggested HAS is a combination of stimulation of paralyzed distal segments (hand) in synchrony with robot controlled movements of proximal segments (upper arm and forearm). The use of HAS is envisioned as part of voluntary activation of preserved sensory-motor systems during task related exercise. This HAS design follows our results from functional electrical therapy, constraint induced movement therapy, intensive exercise therapy, and use of robots for rehabilitation. The suggestion is also based on strong evidences that cortical plasticity is best promoted by task related exercise and patterned electrical stimulation.

A possible source mechanism of the 1946 Unimak Alaska far-field tsunami, uplift of the mid-slope terrace above a splay fault zone

USGS Publications Warehouse

von Huene, Roland E.; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter

2016-01-01

In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of “tsunami” earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

A Possible Source Mechanism of the 1946 Unimak Alaska Far-Field Tsunami: Uplift of the Mid-Slope Terrace Above a Splay Fault Zone

NASA Astrophysics Data System (ADS)

von Huene, Roland; Miller, John J.; Klaeschen, Dirk; Dartnell, Peter

2016-12-01

In 1946, megathrust seismicity along the Unimak segment of the Alaska subduction zone generated the largest ever recorded Alaska/Aleutian tsunami. The tsunami severely damaged Pacific islands and coastal areas from Alaska to Antarctica. It is the charter member of "tsunami" earthquakes that produce outsized far-field tsunamis for the recorded magnitude. Its source mechanisms were unconstrained by observations because geophysical data for the Unimak segment were sparse and of low resolution. Reprocessing of legacy geophysical data reveals a deep water, high-angle reverse or splay thrust fault zone that leads megathrust slip upward to the mid-slope terrace seafloor rather than along the plate boundary toward the trench axis. Splay fault uplift elevates the outer mid-slope terrace and its inner area subsides. Multibeam bathymetry along the splay fault zone shows recent but undated seafloor disruption. The structural configuration of the nearby Semidi segment is similar to that of the Unimak segment, portending generation of a future large tsunami directed toward the US West coast.

Influence of margin segmentation and anomalous volcanism upon the break-up of the Hatton Bank rifted margin, west of the UK

NASA Astrophysics Data System (ADS)

Elliott, G. M.; Parson, L. M.

2007-12-01

The Hatton Bank margin, flanking the Iceland Basin is a widely cited example of a volcanic rifted margin. Prior to this study insights into the break-up history of the margin have been limited to profiles in the north and south, yet whilst valuable, the along margin tectono-magmatic variability has not been revealed. Over 5660 line km of high quality reflection seismic profiles with supplementary multibeam bathymetry were collected to support the UK's claim to Hatton region under the United Nations Convention on Law of the Sea (UNCLOS). Integration of this new data with existing profiles, allowed the margin to be divided into three segments, each of which are flanked by oceanic crust with a smooth upper surface and internal dipping reflectors. The southernmost segment is characterised by a series of inner and outer seaward dipping reflector (SDR) packages, which are separated by an outer high feature. The outer SDR are truncated by Endymion Spur, a chain of steep sided, late stage volcanic cones linked with necks. The central sector has no inner SDR package and is characterised by the presence of a highly intruded continental block, the Hatton Bank Block (HBB). The northern sector is adjacent to Lousy Bank, with a wider region of SDR recognised than to the south and a high amount of volcanic cones imaged. The variations in the distribution of the SDR's along the margin, the presence of the HBB and Endymion Spur all suggest that the break-up process was not uniform alongstrike. The division of the margin into three sectors reveals that structural segmentation played an important role in producing the variations along the margin. Break- up initiated in the south and progressed north producing the SDR packages witnessed, when the HBB was encountered the focus of break-up moved seaward of the block. The northern sector was closer to the Iceland Hotspot and hence a greater amount of volcanism is encountered. The smooth oceanic basement also indicates a high thermal flux leading to high melt production and subsidence rates forming the dipping reflectors. Shortly after break-up the eruption of Endymion Spur occurred. The nature of the magma erupted is unknown but from the steepness of the cones, it is inferred to be viscous and considering the setting, mostly likely a tholeiitic cumulate. A possible trigger for the Endymion Spur is the passage of a pulse of hotter than normal asthenospheric material along the margin, which interacted with lower crustal material to produce melt to feed the volcanic centres. Enhanced asthenospheric heat flow has been invoked to explain the V-shaped ridges along the present day Reykjanes Ridge and it is probable that the Endymion Spur represents previous such pulses along the margin/spreading axis. The location of the enhanced volcanism is itself controlled by crustal segmentation, with the Endymion Spur limited to the southern sector. The crustal thickness in this sector is approx. 2 to 3 km thinner than that found in the central segment, in which Endymion Spur is absent. The role of the segmentation along the margin has influenced the break-up style (presence or absence of SDR) and also the location and nature of post break-up volcanism.

Localization of damage in progressive hydroxychloroquine retinopathy on and off the drug: inner versus outer retina, parafovea versus peripheral fovea.

PubMed

de Sisternes, Luis; Hu, Julia; Rubin, Daniel L; Marmor, Michael F

2015-05-01

To evaluate the relative involvement of inner and outer retina in hydroxychloroquine (HCQ) retinopathy while on the drug, and after drug cessation, using data from spectral-domain optical coherence tomography (SD-OCT). A total of 102 SD-OCT scans were obtained from 11 patients (classified as having early, moderate, or severe stages of toxicity) over a period of 4 years after cessation of HCQ. The inner and outer retina boundaries were identified automatically to measure thickness and characterize progression topographically. The segmentation of retinal layers was verified in SD-OCT cross-sections for all eyes and scans included in this study (a total of 102 scans). Topographic analysis showed that inner retina was not involved in HCQ toxicity to any meaningful degree, either between stages of retinopathy or after the drug is stopped. The characteristic bull's eye pattern of outer macula thinning appears when comparing moderate retinopathy (before any RPE damage) to the early stage. Later damage, as toxicity evolved to a severe stage, was diffuse across most of the macula. If the drug was stopped at an early or moderate stage, progression was limited to the first year and occurred diffusely without parafoveal localization. Hydroxychloroquine retinopathy primarily involves outer retina (photoreceptors). Outer retinal thinning while using HCQ initially involves the parafovea, but becomes diffuse across the macula as damage progresses or after drug cessation. When HCQ is stopped at an early or moderate stage (before RPE damage), progression seems to be limited to the first year.

S-net project: Construction of large scale seafloor observatory network for tsunamis and earthquakes in Japan

NASA Astrophysics Data System (ADS)

Mochizuki, M.; Kanazawa, T.; Uehira, K.; Shimbo, T.; Shiomi, K.; Kunugi, T.; Aoi, S.; Matsumoto, T.; Sekiguchi, S.; Yamamoto, N.; Takahashi, N.; Shinohara, M.; Yamada, T.

2016-12-01

National Research Institute for Earth Science and Disaster Resilience ( NIED ) has launched the project of constructing an observatory network for tsunamis and earthquakes on the seafloor. The observatory network was named "S-net, Seafloor Observation Network for Earthquakes and Tsunamis along the Japan Trench". The S-net consists of 150 seafloor observatories which are connected in line with submarine optical cables. The total length of submarine optical cable is about 5,700 km. The S-net system extends along Kuril and Japan trenches around Japan islands from north to south covering the area between southeast off island of Hokkaido and off the Boso Peninsula, Chiba Prefecture. The project has been financially supported by MEXT Japan. An observatory package is 34cm in diameter and 226cm long. Each observatory equips two units of a high sensitive water-depth sensor as a tsunami meter and four sets of three-component seismometers. The water-depth sensor has measurement resolution of sub-centimeter level. Combination of multiple seismometers secures wide dynamic range and robustness of the observation that are needed for early earthquake warning. The S-net is composed of six segment networks that consists of about 25 observatories and 800-1,600km length submarine optical cable. Five of six segment networks except the one covering the outer rise area of the Japan Trench has been already installed. The data from the observatories on those five segment networks are being transferred to the data center at NIED on a real-time basis, and then verification of data integrity are being carried out at the present moment. Installation of the last segment network of the S-net, that is, the outer rise one is scheduled to be finished within FY2016. Full-scale operation of the S-net will start at FY2017. We will report construction and operation of the S-net submarine cable system as well as the outline of the obtained data in this presentation.

Texture analysis improves level set segmentation of the anterior abdominal wall

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Zhoubing; Allen, Wade M.; Baucom, Rebeccah B.

2013-12-15

Purpose: The treatment of ventral hernias (VH) has been a challenging problem for medical care. Repair of these hernias is fraught with failure; recurrence rates ranging from 24% to 43% have been reported, even with the use of biocompatible mesh. Currently, computed tomography (CT) is used to guide intervention through expert, but qualitative, clinical judgments, notably, quantitative metrics based on image-processing are not used. The authors propose that image segmentation methods to capture the three-dimensional structure of the abdominal wall and its abnormalities will provide a foundation on which to measure geometric properties of hernias and surrounding tissues and, therefore,more » to optimize intervention.Methods: In this study with 20 clinically acquired CT scans on postoperative patients, the authors demonstrated a novel approach to geometric classification of the abdominal. The authors’ approach uses a texture analysis based on Gabor filters to extract feature vectors and follows a fuzzy c-means clustering method to estimate voxelwise probability memberships for eight clusters. The memberships estimated from the texture analysis are helpful to identify anatomical structures with inhomogeneous intensities. The membership was used to guide the level set evolution, as well as to derive an initial start close to the abdominal wall.Results: Segmentation results on abdominal walls were both quantitatively and qualitatively validated with surface errors based on manually labeled ground truth. Using texture, mean surface errors for the outer surface of the abdominal wall were less than 2 mm, with 91% of the outer surface less than 5 mm away from the manual tracings; errors were significantly greater (2–5 mm) for methods that did not use the texture.Conclusions: The authors’ approach establishes a baseline for characterizing the abdominal wall for improving VH care. Inherent texture patterns in CT scans are helpful to the tissue classification, and texture analysis can improve the level set segmentation around the abdominal region.« less

Cone Structure in Patients With Usher Syndrome Type III and Mutations in the Clarin 1 Gene

PubMed Central

Ratnam, Kavitha; Västinsalo, Hanna; Roorda, Austin; Sankila, Eeva-Marja K.; Duncan, Jacque L.

2015-01-01

Objective To study macular structure and function in patients with Usher syndrome type III (USH3) caused by mutations in the Clarin 1 gene (CLRN1). Methods High-resolution macular images were obtained by adaptive optics scanning laser ophthalmoscopy and spectral domain optical coherence tomography in 3 patients with USH3 and were compared with those of age-similar control subjects. Vision function measures included best-corrected visual acuity, kinetic and static perimetry, and full-field electroretinography. Coding regions of the CLRN1 gene were sequenced. Results CLRN1 mutations were present in all the patients; a 20-year-old man showed compound heterozygous mutations (p.N48K and p.S188X), and 2 unrelated women aged 25 and 32 years had homozygous mutations (p.N48K). Best-corrected visual acuity ranged from 20/16 to 20/40, with scotomas beginning at 3° eccentricity. The inner segment-outer segment junction or the inner segment ellipsoid band was disrupted within 1° to 4° of the fovea, and the foveal inner and outer segment layers were significantly thinner than normal. Cones near the fovea in patients 1 and 2 showed normal spacing, and the preserved region ended abruptly. Retinal pigment epithelial cells were visible in patient 3 where cones were lost. Conclusions Cones were observed centrally but not in regions with scotomas, and retinal pigment epithelial cells were visible in regions without cones in patients with CLRN1 mutations. High-resolution measures of retinal structure demonstrate patterns of cone loss associated with CLRN1 mutations. Clinical Relevance These findings provide insight into the effect of CLRN1 mutations on macular cone structure, which has implications for the development of treatments for USH3. Trial Registration clinicaltrials.gov Identifier: NCT00254605 PMID:22964989

Comparison of Two Different Doses of Intrathecal Levobupivacaine for Transurethral Endoscopic Surgery

PubMed Central

Dizman, Secil; Turker, Gurkan; Gurbet, Alp; Mogol, Elif Basagan; Turkcan, Suat; Karakuzu, Ziyaatin

2011-01-01

Objective: To evaluate the effects of two different spinal isobaric levobupivacaine doses on spinal anesthesia characteristics and to find the minimum effective dose for surgery in patients undergoing transurethral resection (TUR) surgery. Materials and Methods: Fifty male patients undergoing TUR surgery were included in the study and were randomized into two equal groups: Group LB10 (n=25): 10 mg 0.5% isobaric levobupivacaine (2 ml) and Group LB15 (n=25): 15 mg 0.75% isobaric levobupivacaine (2 ml). Spinal anesthesia was administered via a 25G Quincke spinal needle through the L3–4 intervertebral space. Sensorial block levels were evaluated using the ‘pin-prick test’, and motor block levels were evaluated using the ‘Bromage scale’. The sensorial and motor block characteristics of patients during intraoperative and postoperative periods and recovery time from spinal anesthesia were evaluated. Results: In three cases in the Group LB10, sensorial block did not reach the T10 level. Complete motor block (Bromage=3) did not occur in eight cases in the Group LB10 and in five cases in the Group LB15. The highest sensorial dermatomal level detected was higher in Group LB15. In Group LB15, sensorial block initial time and the time of complete motor block occurrence were significantly shorter than Group LB10. Hypotension was observed in one case in Group LB15. No significant difference between groups was detected in two segments of regression times: the time to S2 regression and complete sensorial block regression time. Complete motor block regression time was significantly longer in Group LB15 than in Group LB10 (p<0.01). Conclusion: Our findings showed that the minimum effective spinal isobaric levobupivacaine dose was 10 mg for TUR surgery. PMID:25610173

Central Projections of Antennal and Labial Palp Sensory Neurons in the Migratory Armyworm Mythimna separata

PubMed Central

Ma, Bai-Wei; Zhao, Xin-Cheng; Berg, Bente G.; Xie, Gui-Ying; Tang, Qing-Bo; Wang, Gui-Rong

2017-01-01

The oriental armyworm, Mythimna separata (Walker), is a polyphagous, migratory pest relying on olfactory cues to find mates, locate nectar, and guide long-distance flight behavior. In the present study, a combination of neuroanatomical techniques were utilized on this species, including backfills, confocal microscopy, and three-dimensional reconstructions, to trace the central projections of sensory neurons from the antenna and the labial pit organ, respectively. As previously shown, the axons of the labial sensory neurons project via the ipsilateral labial nerve and terminate in three main areas of the central nervous system: (1) the labial-palp pit organ glomerulus of each antennal lobe, (2) the gnathal ganglion, and (3) the prothoracic ganglion of the ventral nerve cord. Similarly, the antennal sensory axons project to multiple areas of the central nervous system. The ipsilateral antennal nerve targets mainly the antennal lobe, the antennal mechanosensory and motor center, and the prothoracic and mesothoracic ganglia. Specific staining experiments including dye application to each of the three antennal segments indicate that the antennal lobe receives input from flagellar olfactory neurons exclusively, while the antennal mechanosensory and motor center is innervated by mechanosensory neurons from the whole antenna, comprising the flagellum, pedicle, and scape. The terminals in the mechanosensory and motor center are organized in segregated zones relating to the origin of neurons. The flagellar mechanosensory axons target anterior zones, while the pedicular and scapal axons terminate in posterior zones. In the ventral nerve cord, the processes from the antennal sensory neurons terminate in the motor area of the thoracic ganglia, suggesting a close connection with motor neurons. Taken together, the numerous neuropils innervated by axons both from the antenna and labial palp indicate the multiple roles these sensory organs serve in insect behavior. PMID:29209176

Provenance of sand on the Poverty Bay shelf, the link between source and sink sectors of the Waipaoa River sedimentary system

NASA Astrophysics Data System (ADS)

Parra, Julie G.; Marsaglia, Kathleen M.; Rivera, Kevin S.; Dawson, Shelby T.; Walsh, J. P.

2012-12-01

The Poverty Shelf, North Island, New Zealand, is a segment of the Waipaoa Sedimentary System (WSS), a MARGINS Source-to-Sink focus site. Our petrographic analysis of sand from shelf core samples indicates that the sand fraction is mainly derived from intra- and potentially extrabasinal sources, but surprisingly, the major fluvial system that drains into Poverty Bay, the Waipaoa River (mean %QFL = xQyFzL), is not the dominant source. Only one vibracore at the mouth of Poverty Bay contained sand (%QFL = xQyFzL) potentially derived from the Waipaoa River. The shelf sand (mean %QFL = xQyFzL) more strongly resembles beach sand (mean %QFL = xQyFzL) collected along the coast, which is likely sourced from pervasive local cliff erosion of Miocene-Pliocene sedimentary units that exhibit similar sandstone detrital modes (mean %QFL = xQyFzL). Texturally, coarser, more poorly sorted and more angular sand is located along the outer shelf, while finer, well-sorted sand characterizes the mid-shelf. These findings suggest a shorter transport history for the material near the outer-shelf bathymetric high areas, and this observation along with the composition data suggests that they were sourced by erosion of locally exposed Miocene-Pliocene units. A potential extrabasinal source of shelf sediment is indicated by anomalous prolate and equant-shaped greywacke (Torlesse) and minor red chert pebbles collected in two outer-shelf box cores on the Lachlan anticline; these are not lithologies found within the terrestrial segment of the WSS or strata comprising the outer-shelf highs. The clast shapes are also distinctly different from the oblate-shaped, pebble-sized greywacke gravel clasts on beaches in Hawke Bay. Rather, these sediments are more similar to Torlesse stream gravel. Seismic and multibeam data support the possibility that during the most recent sea-level lowstand, the Hawke Bay fluvial system flowed into Poverty Canyon, bringing these unique gravels onto what is now the Poverty outer shelf. The presence of the Torlesse gravel is significant in that it highlights how the WSS was not a closed sedimentary system in the past, just as recent sedimentary research has shown in the case today.

Conditional Deletion of N-Myc Disrupts Neurosensory and Non-sensory Development of the Ear

PubMed Central

Kopecky, Benjamin; Santi, Peter; Johnson, Shane; Schmitz, Heather; Fritzsch, Bernd

2011-01-01

Ear development requires interactions of transcription factors for proliferation and differentiation. The proto-oncogene N-Myc is a member of the Myc family that regulate proliferation. To investigate the function of N-Myc, we conditionally knocked out N-Myc in the ear using Tg(Pax2-Cre) and Foxg 1KiCre. N-Myc CKOs had reduced growth of the ear, abnormal morphology including fused sensory epithelia, disrupted histology, and disorganized neuronal innervation. Using Thin-Sheet Laser Imaging Microscopy (TSLIM), 3D reconstruction and quantification of the cochlea revealed a greater than fifty percent size reduction. Immunochemistry and in situ hybridization showed a gravistatic organ-cochlear fusion and a “circularized” apex with no clear inner and outer hair cells. Furthermore, the abnormally developed cochlea had cross innervation from the vestibular ganglion near the basal tip. These findings are put in the context of the possible functional relationship of N-Myc with a number of other cell proliferative and fate determining genes during ear development. PMID:21448975

Fatty Acid Profile, Phenolics and Flavonoids Contents in Olea europaea L. Callus Culture cv. cornicabra.

PubMed

Rodríguez-Hernandez, Ludwi; Nájera-Gomez, Humberto; Luján-Hidalgo, Maria Celína; Ruiz-Lau, Nancy; Lecona-Guzmán, Carlos Alberto; Abud-Archila, Miguel; Ruíz-Valdiviezo, Víctor Manuel; Gutiérrez-Miceli, Federico Antonio

2018-05-01

Olive trees are one of the most important oil crops in the world due to the sensorial and nutritional characteristics of olive oil, such as lipid composition and antioxidant content, and the medicinal properties of its leaves. In this paper, callus formation was induced using nodal segments of olive tree (Olea europaea cv. cornicabra) as explants. Fatty acid profile, total phenolic compounds and total flavonoid compounds were determined in callus culture after 15 weeks and compared with leaf and nodal segments tissues. There was no statistical difference in phenolic compounds among leaf, nodal segments and callus culture, whereas flavonoid compounds were higher in leaf. Fatty acid profile was similar in leaf, nodal segments and callus culture and was constituted by hexadecanoic acid, octadecanoic acid, cis-9-octadecenoic acid, cis-9,12-octadecadienoic acid, cis-9,12,15-octadecatrienoic acid. Hexadecanoic acid was the main fatty acid in callus, leaf and nodal segments with 35.0, 39.0 and 40.0% (w/w), of the lipid composition, respectively. With this paper, it is being reported for the first time the capacity of callus culture to accumulate fatty acids. Our results could serve to continue studying the production of fatty acids in callus cultivation as a biotechnological tool to improve different olive cultivars.

Polyethylene glycol treated allografts not tissue matched nor immunosuppressed rapidly repair sciatic nerve gaps, maintain neuromuscular functions, and restore voluntary behaviors in female rats.

PubMed

Mikesh, Michelle; Ghergherehchi, Cameron L; Rahesh, Sina; Jagannath, Karthik; Ali, Amir; Sengelaub, Dale R; Trevino, Richard C; Jackson, David M; Tucker, Haley O; Bittner, George D

2018-07-01

Many publications report that ablations of segments of peripheral nerves produce the following unfortunate results: (1) Immediate loss of sensory signaling and motor control; (2) rapid Wallerian degeneration of severed distal axons within days; (3) muscle atrophy within weeks; (4) poor behavioral (functional) recovery after many months, if ever, by slowly-regenerating (∼1mm/d) axon outgrowths from surviving proximal nerve stumps; and (5) Nerve allografts to repair gap injuries are rejected, often even if tissue matched and immunosuppressed. In contrast, using a female rat sciatic nerve model system, we report that neurorrhaphy of allografts plus a well-specified-sequence of solutions (one containing polyethylene glycol: PEG) successfully addresses each of these problems by: (a) Reestablishing axonal continuity/signaling within minutes by nonspecific ally PEG-fusing (connecting) severed motor and sensory axons across each anastomosis; (b) preventing Wallerian degeneration by maintaining many distal segments of inappropriately-reconnected, PEG-fused axons that continuously activate nerve-muscle junctions; (c) maintaining innervation of muscle fibers that undergo much less atrophy than otherwise-denervated muscle fibers; (d) inducing remarkable behavioral recovery to near-unoperated levels within days to weeks, almost certainly by CNS and PNS plasticities well-beyond what most neuroscientists currently imagine; and (e) preventing rejection of PEG-fused donor nerve allografts with no tissue matching or immunosuppression. Similar behavioral results are produced by PEG-fused autografts. All results for Negative Control allografts agree with current neuroscience data 1-5 given above. Hence, PEG-fusion of allografts for repair of ablated peripheral nerve segments expand on previous observations in single-cut injuries, provoke reconsideration of some current neuroscience dogma, and further extend the potential of PEG-fusion in clinical practice. © 2018 Wiley Periodicals, Inc.

Longitudinal assessment of retinal structure and function reveals a rod-cone degeneration in a guinea pig model initially presented as night blind.

PubMed

Racine, Julie; Joly, Sandrine; Lachapelle, Pierre

2011-08-01

We have previously reported a naturally occurring retinopathy in a population of guinea pigs, where the affected animals presented a defect of the rod-mediated vision. The purpose of this study was to investigate if the mutants were affected with a stationary or degenerative retinopathy and to identify the cellular origin of this unique disorder. Electroretinogram (ERG) [postnatal day 1 (P1) to P450], light (LM) and electron microscopy (EM) [P5, P150, P450], and immunohistochemistry [P30, P150, P450] were evaluated from normal and mutant animals. Irrespective of age, the scotopic ERGs of mutants could only be evoked by bright flashes, and the resulting ERGs were of photopic waveform. Interestingly, the amplitude of the cone and the rod/cone a-waves was always of smaller amplitude in mutants, but this difference tended to decrease with age. In contrast, the b-waves were of larger amplitude than normal in photopic ERGs obtained prior to age 25 (days) and prior to age 10 for rod/cone ERGs. LM revealed, in mutants, an absence of the outer segment layer (OSL) with a reduction in the outer nuclear layer (ONL) thickness. EM disclosed the presence of cone outer segment (OS) while no rod OS could be evidenced. Immunohistochemistry revealed the presence of rhodopsin, both cone opsins as well as normal synaptophysin immunoreactivity. Finally, neither the retinal structure nor the function in the mutants achieved normal development. Results suggest that mutant animals are suffering from a degenerative retinal disorder that affects the structure and function of rods and cones.

Detailed functional and structural phenotype of Bietti crystalline dystrophy associated with mutations in CYP4V2 complicated by choroidal neovascularization.

PubMed

Fuerst, Nicole M; Serrano, Leona; Han, Grace; Morgan, Jessica I W; Maguire, Albert M; Leroy, Bart P; Kim, Benjamin J; Aleman, Tomas S

2016-12-01

To describe in detail the phenotype of a patient with Bietti crystalline dystrophy (BCD) complicated by choroidal neovascularization (CNV) and the response to intravitreal Bevacizumab (Avastin ® ; Genentech/Roche). A 34-year-old woman with BCD and mutations in CYP4V2 (c.802-8_806del13/p.H331P:c992A>C) underwent a complete ophthalmic examination, full-field flash electroretinography (ERG), kinetic and two-color dark-adapted perimetry, and dark-adaptometry. Imaging was performed with spectral domain optical coherence tomography (SD-OCT), near infrared (NIR) and short wavelength (SW) fundus autofluorescence (FAF), and fluorescein angiography (FA). Best-corrected visual acuity (BCVA) was 20/20 and 20/60 for the right and left eye, respectively. There were corneal paralimbal crystal-like deposits. Kinetic fields were normal in the peripheral extent. Retinal crystals were most obvious on NIR-reflectance and corresponded with hyperreflectivities within the RPE on SD-OCT. There was parafoveal/perifoveal hypofluorescence on SW-FAF and NIR-FAF. Rod > cone sensitivity loss surrounded fixation and extended to ~10° of eccentricity corresponding to regions of photoreceptor outer segment-retinal pigmented epithelium (RPE) interdigitation abnormalities. The outer nuclear layer was normal in thickness. Recovery of sensitivity following a ~76% rhodopsin bleach was normal. ERGs were normal. A subretinal hemorrhage in the left eye co-localized with elevation of the RPE on SD-OCT and leakage on FA, suggestive of CNV. Three monthly intravitreal injections of Bevacizumab led to restoration of BCVA to baseline (20/25). crystals in BCD were predominantly located within the RPE. Photoreceptor outer segment and apical RPE abnormalities underlie the relatively extensive retinal dysfunction observed in relatively early-stage BCD. Intravitreal Bevacizumab was effective in treating CNV in this setting.

Photoreceptor Layer Thickness Changes During Dark Adaptation Observed With Ultrahigh-Resolution Optical Coherence Tomography.

PubMed

Lu, Chen D; Lee, ByungKun; Schottenhamml, Julia; Maier, Andreas; Pugh, Edward N; Fujimoto, James G

2017-09-01

To examine outer retinal band changes after flash stimulus and subsequent dark adaptation with ultrahigh-resolution optical coherence tomography (UHR-OCT). Five dark-adapted left eyes of five normal subjects were imaged with 3-μm axial-resolution UHR-OCT during 30 minutes of dark adaptation following 96%, 54%, 23%, and 0% full-field and 54% half-field rhodopsin bleach. We identified the ellipsoid zone inner segment/outer segment (EZ[IS/OS]), cone interdigitation zone (CIZ), rod interdigitation zone (RIZ), retinal pigment epithelium (RPE), and Bruch's membrane (BM) axial positions and generated two-dimensional thickness maps of the EZ(IS/OS) to the four bands. The average thickness over an area of the thickness map was compared against that of the dark-adapted baselines. The time-dependent thickness changes (photoresponses) were statistically compared against 0% bleach. Dark adaptometry was performed with the same bleaching protocol. The EZ(IS/OS)-CIZ photoresponse was significantly different at 96% (P < 0.0001) and 54% (P = 0.006) bleach. At all three bleaching levels, the EZ(IS/OS)-RIZ, -RPE, and -BM responses were significantly different (P < 0.0001). The EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ time courses were similar to the recovery of rod- and cone-mediated sensitivity, respectively, measured with dark adaptometry. The maximal EZ(IS/OS)-CIZ and EZ(IS/OS)-RIZ response magnitudes doubled from 54% to 96% bleach. Both EZ(IS/OS)-RPE and EZ(IS/OS)-BM responses resembled dampened oscillations that were graded in amplitude and duration with bleaching intensity. Half-field photoresponses were localized to the stimulated retina. With noninvasive, near-infrared UHR-OCT, we characterized three distinct, spatially localized photoresponses in the outer retinal bands. These photoresponses have potential value as physical correlates of photoreceptor function.

Role of female sex hormones in neuronal nitric oxide release and metabolism in rat mesenteric arteries.

PubMed

Minoves, Nuria; Balfagón, Gloria; Ferrer, Mercedes

2002-09-01

This study examines the effects of female sex hormones on the vasoconstrictor response to electrical field stimulation (EFS), as well as the modulation of this response by neuronal NO. For this purpose, segments of denuded superior mesenteric artery from ovariectomized (OvX) female Sprague-Dawley rats and from control rats (in oestrus phase) were used. EFS induced frequency-dependent contractions, which were greater in segments from OvX rats than in those from control rats. The NO synthase inhibitor N(G)-nitro-l-arginine methyl ester strengthened EFS-elicited contractions to a greater extent in arteries from OvX rats than in those from control rats. Similar results were observed with the preferential neuronal NO synthase inhibitor 7-nitroindazole. The sensorial neurotoxin capsaicin did not modify EFS-induced contractions in segments from either group. In noradrenaline-precontracted segments, sodium nitroprusside (SNP) induced concentration-dependent relaxation, which was greater in segments from control rats than in those from OvX rats. 8-Bromo-cGMP induced similar concentration-dependent relaxation in noradrenaline-precontracted segments from both OvX and control rats. Diethyldithiocarbamate, a superoxide dismutase (SOD) inhibitor, reduced the relaxation induced by SNP in segments from both groups of rats. SOD, a superoxide anion scavenger, enhanced the relaxation induced by SNP in segments from OvX rats, but did not modify it in segments from control rats. EFS induced NO(-)(2) formation, which was greater in segments from OvX than in those from control rats, and pretreatment with tetrodotoxin, a blocker of nerve impulse propagation, abolished release in both cases. These results suggest that EFS induces greater neuronal NO release in mesenteric segments from OvX rats than in those from control rats and, although NO metabolism is also higher, the contribution of net neuronal NO in the vasomotor response to EFS is greater in segments from OvX rats than in those from control rats.

Automatic segmentation of the facial nerve and chorda tympani in pediatric CT scans.

PubMed

Reda, Fitsum A; Noble, Jack H; Rivas, Alejandro; McRackan, Theodore R; Labadie, Robert F; Dawant, Benoit M

2011-10-01

Cochlear implant surgery is used to implant an electrode array in the cochlea to treat hearing loss. The authors recently introduced a minimally invasive image-guided technique termed percutaneous cochlear implantation. This approach achieves access to the cochlea by drilling a single linear channel from the outer skull into the cochlea via the facial recess, a region bounded by the facial nerve and chorda tympani. To exploit existing methods for computing automatically safe drilling trajectories, the facial nerve and chorda tympani need to be segmented. The goal of this work is to automatically segment the facial nerve and chorda tympani in pediatric CT scans. The authors have proposed an automatic technique to achieve the segmentation task in adult patients that relies on statistical models of the structures. These models contain intensity and shape information along the central axes of both structures. In this work, the authors attempted to use the same method to segment the structures in pediatric scans. However, the authors learned that substantial differences exist between the anatomy of children and that of adults, which led to poor segmentation results when an adult model is used to segment a pediatric volume. Therefore, the authors built a new model for pediatric cases and used it to segment pediatric scans. Once this new model was built, the authors employed the same segmentation method used for adults with algorithm parameters that were optimized for pediatric anatomy. A validation experiment was conducted on 10 CT scans in which manually segmented structures were compared to automatically segmented structures. The mean, standard deviation, median, and maximum segmentation errors were 0.23, 0.17, 0.18, and 1.27 mm, respectively. The results indicate that accurate segmentation of the facial nerve and chorda tympani in pediatric scans is achievable, thus suggesting that safe drilling trajectories can also be computed automatically.

Speech Rhythms and Multiplexed Oscillatory Sensory Coding in the Human Brain

PubMed Central

Gross, Joachim; Hoogenboom, Nienke; Thut, Gregor; Schyns, Philippe; Panzeri, Stefano; Belin, Pascal; Garrod, Simon

2013-01-01

Cortical oscillations are likely candidates for segmentation and coding of continuous speech. Here, we monitored continuous speech processing with magnetoencephalography (MEG) to unravel the principles of speech segmentation and coding. We demonstrate that speech entrains the phase of low-frequency (delta, theta) and the amplitude of high-frequency (gamma) oscillations in the auditory cortex. Phase entrainment is stronger in the right and amplitude entrainment is stronger in the left auditory cortex. Furthermore, edges in the speech envelope phase reset auditory cortex oscillations thereby enhancing their entrainment to speech. This mechanism adapts to the changing physical features of the speech envelope and enables efficient, stimulus-specific speech sampling. Finally, we show that within the auditory cortex, coupling between delta, theta, and gamma oscillations increases following speech edges. Importantly, all couplings (i.e., brain-speech and also within the cortex) attenuate for backward-presented speech, suggesting top-down control. We conclude that segmentation and coding of speech relies on a nested hierarchy of entrained cortical oscillations. PMID:24391472

Mechanisms of Retinal Damage from Chronic Laser Radiation.

DTIC Science & Technology

1981-07-01

culture. The pigment epithelium is deter- mined to be almost equally susceptible to damage in vitro as in vivo and the same action spectrum is similar in...92 -97 D. Experiment III. Light Damage in Culture of Bovine Retinal Pigment Epithelium 1. Methodology a. Collection of Cells... epithelium : Mild form of damage. Figure 18 Inner segments severely damaged. Figure 19 : Cone pedicle after exposure. Figure 20 Outer plexiform layer

This pineal gland does not mediate phase shifts in the disc shedding rhythm of the rat retina

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldman, A.I.

Albino rats were subjected to pinealectomy, superior cervical ganglionectomy, or the appropriate sham preparation and were placed in lighting conditions so that light onset was advanced by 10 hr. After 6 days of this regimen, all animals exhibited a complete shift in their outer segment disc shedding rhythm, indicating that the pineal gland is not a factor in mediating such a shift.

Comparative study of human embryonic stem cells (hESC) and human induced pluripotent stem cells (hiPSC) as a treatment for retinal dystrophies

PubMed Central

Riera, Marina; Fontrodona, Laura; Albert, Silvia; Ramirez, Diana Mora; Seriola, Anna; Salas, Anna; Muñoz, Yolanda; Ramos, David; Villegas-Perez, Maria Paz; Zapata, Miguel Angel; Raya, Angel; Ruberte, Jesus; Veiga, Anna; Garcia-Arumi, Jose

2016-01-01

Retinal dystrophies (RD) are major causes of familial blindness and are characterized by progressive dysfunction of photoreceptor and/or retinal pigment epithelium (RPE) cells. In this study, we aimed to evaluate and compare the therapeutic effects of two pluripotent stem cell (PSC)-based therapies. We differentiated RPE from human embryonic stem cells (hESCs) or human-induced pluripotent stem cells (hiPSCs) and transplanted them into the subretinal space of the Royal College of Surgeons (RCS) rat. Once differentiated, cells from either source of PSC resembled mature RPE in their morphology and gene expression profile. Following transplantation, both hESC- and hiPSC-derived cells maintained the expression of specific RPE markers, lost their proliferative capacity, established tight junctions, and were able to perform phagocytosis of photoreceptor outer segments. Remarkably, grafted areas showed increased numbers of photoreceptor nuclei and outer segment disk membranes. Regardless of the cell source, human transplants protected retina from cell apoptosis, glial stress and accumulation of autofluorescence, and responded better to light stimuli. Altogether, our results show that hESC- and hiPSC-derived cells survived, migrated, integrated, and functioned as RPE in the RCS rat retina, providing preclinical evidence that either PSC source could be of potential benefit for treating RD. PMID:27006969

Negative regulation of ciliary length by ciliary male germ cell-associated kinase (Mak) is required for retinal photoreceptor survival.

PubMed

Omori, Yoshihiro; Chaya, Taro; Katoh, Kimiko; Kajimura, Naoko; Sato, Shigeru; Muraoka, Koichiro; Ueno, Shinji; Koyasu, Toshiyuki; Kondo, Mineo; Furukawa, Takahisa

2010-12-28

Cilia function as cell sensors in many organs, and their disorders are referred to as "ciliopathies." Although ciliary components and transport machinery have been well studied, regulatory mechanisms of ciliary formation and maintenance are poorly understood. Here we show that male germ cell-associated kinase (Mak) regulates retinal photoreceptor ciliary length and subcompartmentalization. Mak was localized both in the connecting cilia and outer-segment axonemes of photoreceptor cells. In the Mak-null retina, photoreceptors exhibit elongated cilia and progressive degeneration. We observed accumulation of intraflagellar transport 88 (IFT88) and IFT57, expansion of kinesin family member 3A (Kif3a), and acetylated α-tubulin signals in the Mak-null photoreceptor cilia. We found abnormal rhodopsin accumulation in the Mak-null photoreceptor cell bodies at postnatal day 14. In addition, overexpression of retinitis pigmentosa 1 (RP1), a microtubule-associated protein localized in outer-segment axonemes, induced ciliary elongation, and Mak coexpression rescued excessive ciliary elongation by RP1. The RP1 N-terminal portion induces ciliary elongation and increased intensity of acetylated α-tubulin labeling in the cells and is phosphorylated by Mak. These results suggest that Mak is essential for the regulation of ciliary length and is required for the long-term survival of photoreceptors.

Negative regulation of ciliary length by ciliary male germ cell-associated kinase (Mak) is required for retinal photoreceptor survival

PubMed Central

Omori, Yoshihiro; Chaya, Taro; Katoh, Kimiko; Kajimura, Naoko; Sato, Shigeru; Muraoka, Koichiro; Ueno, Shinji; Koyasu, Toshiyuki; Kondo, Mineo; Furukawa, Takahisa

2010-01-01

Cilia function as cell sensors in many organs, and their disorders are referred to as “ciliopathies.” Although ciliary components and transport machinery have been well studied, regulatory mechanisms of ciliary formation and maintenance are poorly understood. Here we show that male germ cell-associated kinase (Mak) regulates retinal photoreceptor ciliary length and subcompartmentalization. Mak was localized both in the connecting cilia and outer-segment axonemes of photoreceptor cells. In the Mak-null retina, photoreceptors exhibit elongated cilia and progressive degeneration. We observed accumulation of intraflagellar transport 88 (IFT88) and IFT57, expansion of kinesin family member 3A (Kif3a), and acetylated α-tubulin signals in the Mak-null photoreceptor cilia. We found abnormal rhodopsin accumulation in the Mak-null photoreceptor cell bodies at postnatal day 14. In addition, overexpression of retinitis pigmentosa 1 (RP1), a microtubule-associated protein localized in outer-segment axonemes, induced ciliary elongation, and Mak coexpression rescued excessive ciliary elongation by RP1. The RP1 N-terminal portion induces ciliary elongation and increased intensity of acetylated α-tubulin labeling in the cells and is phosphorylated by Mak. These results suggest that Mak is essential for the regulation of ciliary length and is required for the long-term survival of photoreceptors. PMID:21148103

Keywords image retrieval in historical handwritten Arabic documents

NASA Astrophysics Data System (ADS)

Saabni, Raid; El-Sana, Jihad

2013-01-01

A system is presented for spotting and searching keywords in handwritten Arabic documents. A slightly modified dynamic time warping algorithm is used to measure similarities between words. Two sets of features are generated from the outer contour of the words/word-parts. The first set is based on the angles between nodes on the contour and the second set is based on the shape context features taken from the outer contour. To recognize a given word, the segmentation-free approach is partially adopted, i.e., continuous word parts are used as the basic alphabet, instead of individual characters or complete words. Additional strokes, such as dots and detached short segments, are classified and used in a postprocessing step to determine the final comparison decision. The search for a keyword is performed by the search for its word parts given in the correct order. The performance of the presented system was very encouraging in terms of efficiency and match rates. To evaluate the presented system its performance is compared to three different systems. Unfortunately, there are no publicly available standard datasets with ground truth for testing Arabic key word searching systems. Therefore, a private set of images partially taken from Juma'a Al-Majid Center in Dubai for evaluation is used, while using a slightly modified version of the IFN/ENIT database for training.

Calorimetric Studies of Bovine Rod Outer Segment Disk Membranes Support a Monomeric Unit for Both Rhodopsin and Opsin

PubMed Central

Edrington, Thomas C.; Bennett, Michael; Albert, Arlene D.

2008-01-01

The photoreceptor rhodopsin is a G-protein coupled receptor that has recently been proposed to exist as a dimer or higher order oligomer, in contrast to the previously described monomer, in retinal rod outer segment disk membranes. Rhodopsin exhibits considerably greater thermal stability than opsin (the bleached form of the receptor), which is reflected in an ∼15°C difference in the thermal denaturation temperatures (Tm) of rhodopsin and opsin as measured by differential scanning calorimetry. Here we use differential scanning calorimetry to investigate the effect of partial bleaching of disk membranes on the Tm of rhodopsin and of opsin in native disk membranes, as well as in cross-linked disk membranes in which rhodopsin dimers are known to be present. The Tms of rhodopsin and opsin are expected to be perturbed if mixed oligomers are present. The Tm remained constant for rhodopsin and opsin in native disks regardless of the level of bleaching. In contrast, the Tm of cross-linked rhodopsin in disk membranes was dependent on the extent of bleaching. The energy of activation for denaturation of rhodopsin and cross-linked rhodopsin was calculated. Cross-linking rhodopsin significantly decreased the energy of activation. We conclude that in native disk membranes, rhodopsin behaves predominantly as a monomer. PMID:18586850

A variant of arrestin-1 binds rod outer segment membranes in a light-independent manner.

PubMed

Uzcanga, Graciela L; Becerra, Aniuska R; Perdomo, Deisy; Bubis, José

2011-03-15

A 50-kDa-polypeptide band peripherally bound to retinal rod outer segment (ROS) membranes was purified by anion-exchange chromatography. When the 50-kDa protein was compared with purified arrestin-1, it was observed that: (1) both proteins comigrated on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and were recognized by either anti-50-kDa protein polyclonal antibodies or anti-arrestin-1 monoclonal antibodies; (2) protein fragments and peptide fingerprint maps obtained following limited and complete proteolysis with specific proteases were very similar for both molecules; and (3) several chromatographically-purified tryptic peptides from the 50-kDa protein possessed the same amino acid composition as tryptic peptides deduced from the reported arrestin-1 primary structure. Consequently, arrestin-1 and the purified 50-kDa protein must correspond to variants of the same molecule. However, in contrast to arrestin-1 that associated to the ROS membranes only in the presence of light and ATP, the 50-kDa protein interacted with the ROS membranes in a light-independent manner, either in the presence or absence of ATP. These results clearly established that phosphorylated and illuminated rhodopsin is not the membrane anchor for this variant of arrestin-1. Copyright © 2010 Elsevier Inc. All rights reserved.

Aneurysm of the Left Atrial Appendage

PubMed Central

Victor, Solomon; Nayak, Vijaya M.

2001-01-01

A 43-year-old woman underwent excision of an aneurysm of the left atrial appendage, which had been causing cerebrovascular embolic episodes. We attribute the aneurysm to congenital dysplasia of the musculi pectinati in the left atrial appendage and of the bands of atrial muscle from which they arise. In Appendix I, we draw attention to the morphologically similar arrangements of inner and outer bands that emanate from a common transverse interatrial band and yield morphologically similar medial, descending, and ascending palm-leaf arrangements of musculi pectinati. In addition, we observe that the strap-like arrangements of musculi in both atria connect the outer band with the para-annular segment of the inner band. In Appendix II, we briefly review the literature concerning musculi pectinati and related bands. PMID:11453121

Defining the Cellular Environment in the Organ of Corti following Extensive Hair Cell Loss: A Basis for Future Sensory Cell Replacement in the Cochlea

PubMed Central

Taylor, Ruth R.; Jagger, Daniel J.; Forge, Andrew

2012-01-01

Background Following the loss of hair cells from the mammalian cochlea, the sensory epithelium repairs to close the lesions but no new hair cells arise and hearing impairment ensues. For any cell replacement strategy to be successful, the cellular environment of the injured tissue has to be able to nurture new hair cells. This study defines characteristics of the auditory sensory epithelium after hair cell loss. Methodology/Principal Findings Studies were conducted in C57BL/6 and CBA/Ca mice. Treatment with an aminoglycoside-diuretic combination produced loss of all outer hair cells within 48 hours in both strains. The subsequent progressive tissue re-organisation was examined using immunohistochemistry and electron microscopy. There was no evidence of significant de-differentiation of the specialised columnar supporting cells. Kir4.1 was down regulated but KCC4, GLAST, microtubule bundles, connexin expression patterns and pathways of intercellular communication were retained. The columnar supporting cells became covered with non-specialised cells migrating from the outermost region of the organ of Corti. Eventually non-specialised, flat cells replaced the columnar epithelium. Flat epithelium developed in distributed patches interrupting regions of columnar epithelium formed of differentiated supporting cells. Formation of the flat epithelium was initiated within a few weeks post-treatment in C57BL/6 mice but not for several months in CBA/Ca's, suggesting genetic background influences the rate of re-organisation. Conclusions/Significance The lack of dedifferentiation amongst supporting cells and their replacement by cells from the outer side of the organ of Corti are factors that may need to be considered in any attempt to promote endogenous hair cell regeneration. The variability of the cellular environment along an individual cochlea arising from patch-like generation of flat epithelium, and the possible variability between individuals resulting from genetic influences on the rate at which remodelling occurs may pose challenges to devising the appropriate regenerative therapy for a deaf patient. PMID:22299045

Investigating the role of MRGPRC11 and capsaicin-sensitive afferent nerves in the anti-influenza effects exerted by SLIGRL-amide in murine airways.

PubMed

Chang, Amy Y; Mann, Tracy S; McFawn, Peter K; Han, Liang; Dong, Xinzhong; Henry, Peter J

2016-05-23

The hexapeptide SLIGRL-amide activates protease-activated receptor-2 (PAR-2) and mas-related G protein-coupled receptor C11 (MRGPRC11), both of which are known to be expressed on populations of sensory nerves. SLIGRL-amide has recently been reported to inhibit influenza A (IAV) infection in mice independently of PAR-2 activation, however the explicit roles of MRGPRC11 and sensory nerves in this process are unknown. Thus, the principal aim of this study was to determine whether SLIGRL-amide-induced inhibition of influenza infection is mediated by MRGPRC11 and/or by capsaicin-sensitive sensory nerves. The inhibitory effect of SLIGRL-amide on IAV infection observed in control mice in vivo was compared to effects produced in mice that did not express MRGPRC11 (mrgpr-cluster∆ (-/-) mice) or had impaired sensory nerve function (induced by chronic pre-treatment with capsaicin). Complementary mechanistic studies using both in vivo and ex vivo approaches investigated whether the anti-IAV activity of SLIGRL-amide was (1) mimicked by either activators of MRGPRC11 (BAM8-22) or by activators (acute capsaicin) or selected mediators (substance P, CGRP) of sensory nerve function, or (2) suppressed by inhibitors of sensory nerve function (e.g. NK1 receptor antagonists). SLIGRL-amide and BAM8-22 dose-dependently inhibited IAV infection in mrgpr-cluster∆ (-/-) mice that do not express MRGPRC11. In addition, SLIGRL-amide and BAM8-22 each inhibited IAV infection in capsaicin-pre-treated mice that lack functional sensory nerves. Furthermore, the anti-IAV activity of SLIGRL-amide was not mimicked by the sensory neuropeptides substance P or CGRP, nor blocked by either NK1 (L-703,606, RP67580) and CGRP receptor (CGRP8-37) antagonists. Direct stimulation of airway sensory nerves through acute exposure to the TRPV1 activator capsaicin also failed to mimic SLIGRL-amide-induced inhibition of IAV infectivity. The anti-IAV activity of SLIGRL-amide was mimicked by the purinoceptor agonist ATP, a direct activator of mucus secretion from airway epithelial cells. Additionally, both SLIGRL-amide and ATP stimulated mucus secretion and inhibited IAV infectivity in mouse isolated tracheal segments. SLIGRL-amide inhibits IAV infection independently of MRGPRC11 and independently of capsaicin-sensitive, neuropeptide-releasing sensory nerves, and its secretory action on epithelial cells warrants further investigation.

Anatomy-guided joint tissue segmentation and topological correction for 6-month infant brain MRI with risk of autism.

PubMed

Wang, Li; Li, Gang; Adeli, Ehsan; Liu, Mingxia; Wu, Zhengwang; Meng, Yu; Lin, Weili; Shen, Dinggang

2018-06-01

Tissue segmentation of infant brain MRIs with risk of autism is critically important for characterizing early brain development and identifying biomarkers. However, it is challenging due to low tissue contrast caused by inherent ongoing myelination and maturation. In particular, at around 6 months of age, the voxel intensities in both gray matter and white matter are within similar ranges, thus leading to the lowest image contrast in the first postnatal year. Previous studies typically employed intensity images and tentatively estimated tissue probabilities to train a sequence of classifiers for tissue segmentation. However, the important prior knowledge of brain anatomy is largely ignored during the segmentation. Consequently, the segmentation accuracy is still limited and topological errors frequently exist, which will significantly degrade the performance of subsequent analyses. Although topological errors could be partially handled by retrospective topological correction methods, their results may still be anatomically incorrect. To address these challenges, in this article, we propose an anatomy-guided joint tissue segmentation and topological correction framework for isointense infant MRI. Particularly, we adopt a signed distance map with respect to the outer cortical surface as anatomical prior knowledge, and incorporate such prior information into the proposed framework to guide segmentation in ambiguous regions. Experimental results on the subjects acquired from National Database for Autism Research demonstrate the effectiveness to topological errors and also some levels of robustness to motion. Comparisons with the state-of-the-art methods further demonstrate the advantages of the proposed method in terms of both segmentation accuracy and topological correctness. © 2018 Wiley Periodicals, Inc.

The computational nature of memory modification.

PubMed

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-03-15

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature.

The perforating branches of the P1 segment of the posterior cerebral artery.

PubMed

Kaya, Ahmet Hilmi; Dagcinar, Adnan; Ulu, Mustafa Onur; Topal, Arif; Bayri, Yasar; Ulus, Aykan; Kopuz, Cem; Sam, Bulent

2010-01-01

The perforating branches of the P1 segment of the posterior cerebral artery are vulnerable to injury. Because of their close proximity to the basilar artery, the vulnerability occurs especially during surgical interventions for vascular pathologies such as basilar apex aneurysms. Therefore, extensive knowledge of the microsurgical anatomy of this area is mandatory to prevent poor post-operative outcomes. We microscopically examined 28 P1 segments obtained from 14 adult fresh cadaver brains (6 silicone injected, 8 freshly examined). The P1 segments ranged between 2.8mm and 12.2mm (mean 6.8mm) in length with a mean outer diameter of 1.85 mm (range 0.8-4.5mm). All 94 thalamoperforating branches identified in 27 P1 segments (mean 3.35 branches per segment) arose from the postero-superior aspect of P1 and were the most proximally originating branch in nearly all specimens (96.4%). In addition in 28 P1s, 12 short circumflex arteries (42.8%; mean 0.42 branches per segment), 16 long circumflex arteries (57.1%; mean 0.57 branches per segment) and 10 medial posterior choroidal arteries (35.7%; mean 0.35 branches per segment) were identified and all originated from the posterior or postero-inferior surface of the P1 segment. When the P1 segment had more than one type of branch, it was the short circumflex arteries that were always more proximal in origin than the others. The medial posterior choroidal arteries were always more distal in origin. All three branches were not observed together in any of the P1 segments. The findings in this, and future, anatomical studies may help to reduce the post-surgical morbidity and mortality rates after surgery for posterior circulation aneurysms. Copyright (c) 2009 Elsevier Ltd. All rights reserved.

Drivers of high-involvement consumers' intention to buy PDO wines: Valpolicella PDO case study.

PubMed

Capitello, Roberta; Agnoli, Lara; Begalli, Diego

2016-08-01

This study investigates whether different sensory profiles of wines belonging to the same Protected Designation of Origin (PDO) are perceived as different products by consumers. It identifies the drivers of consumers' intention to buy preferred wines. Descriptive sensory analysis, consumer tests and consumer interviews were conducted to reach research aims. To perform the consumer tests and interviews, 443 consumers participated in the survey. The tasted wines comprised five samples representative of Valpolicella PDO wine. Analysis of variance tests, principal component analysis and linear and logit regressions were employed to verify the research hypotheses. The results demonstrated: (1) different sensory profiles exist within the Valpolicella PDO wine; (2) these sensory profiles result in consumers having the perception of diversified products; (3) the perception of differences was less marked for consumers than for trained assessors due to the different weight attributed to visual, aroma and the taste/mouthfeel hedonic dimensions; and (4) consumers' liking, as well as general perceptions, attitudes, preferences, wine knowledge and experience, contribute to consumers' intentions to buy more than the socio-demographic characteristics of consumers. The analysis of the drivers of consumers' intention to buy certain PDO wines provides new marketing insights into the roles of intrinsic quality, preferences and consumers' subjective characteristics in market segmentation. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

Sensory characteristics and consumer acceptability of fermented soybean paste (Doenjang).

PubMed

Kim, H G; Hong, J H; Song, C K; Shin, H W; Kim, K O

2010-09-01

This study was conducted to examine the sensory profiles of fermented soybean paste (Doenjang), to understand consumers' acceptability of different types of Doenjang samples and to identify the sensory characteristics that drive consumer acceptability of Doenjang products. Descriptive analysis and consumer acceptability test were conducted for 7 different types of Doenjang samples. The samples included 2 types of Doenjang made by either traditional or commercially modified methods. For the descriptive analysis, 8 trained panelists developed and evaluated 31 descriptors. There were significant differences in all 31 attributes among the samples. Principal component analysis was also performed to summarize the sensory characteristics of the samples. In consumer testing, 200 consumers evaluated the acceptability of Doenjang samples. Significant differences in consumer acceptability were observed among the samples. The consumers preferred the Doenjang samples manufactured using a commercially modified method. In overall point of view, most consumers liked the Doenjang samples that had strong "sweet" and "MSG (monosodium glutamate)" tastes. It appears that "sweet" and "MSG" tastes are the drivers of liking for Doenjang. "Salty" taste, "meju,"traditional Korean soy sauce," and "fermented fish" odor/flavors seem to be the drivers of disliking for Doenjang. Cluster analysis identified 3 subconsumer segments sharing a common preference pattern for the 7 samples within a cluster. The results showed that each consumer cluster preferred different Doenjang samples. External preference mapping was performed to establish the relationships between the sensory attributes and consumer acceptability in each cluster. Consumption of the fermented soybean products is gradually expanding around the world, due to their various health benefits. Therefore, understanding sensory characteristics and consumer acceptability of Doenjang are becoming increasingly important. The intense and complex flavor characteristics of Doenjang make it difficult to obtain a comprehensive sensory profiling and drivers of liking. The finding of this study can be applied to development of a new product that has better consumer acceptability. Also this study can be a useful and effective guideline to researchers who intend to examine the sensory characteristics and consumer acceptability of fermented soybean pastes.

Effect of sensory denervation on the structure and physiologic responsiveness of rabbit lacrimal gland.

PubMed

Meneray, M A; Bennett, D J; Nguyen, D H; Beuerman, R W

1998-01-01

This work was conducted to determine the effects of unilateral trigeminal ganglion ablation on lacrimal gland structure and secretory activity. Adult male New Zealand rabbits underwent unilateral thermocoagulation of the ophthalmic division of the trigeminal ganglion. Sensory denervation was affirmed by anatomic inspection of the lesion and transmission electron microscopy (TEM) of the lacrimal gland innervation. Eight to 10 days after the procedure, the intraorbital lacrimal glands were removed from both sides. To compare the physiologic competence of the intact and denervated glands, freshly isolated gland fragments from the paired intact and denervated glands were stimulated with carbachol (100 microM), isoproterenol (10 microM), phorbol-12,13-dibutyrate (PDBu, 10 microM), forskolin (40 microM), or vehicle. Total secreted protein was measured at 30 or 60 min after the establishment of baseline values. Intact and denervated glands also were examined by light and TEM, and the morphologic appearance of the acinar structures as well as the appearance of nerves innervating the gland after denervation were assessed. Similar experiments were conducted with animals that underwent unilateral superior cervical ganglionectomy. Tissues from sensory denervated glands released significantly more protein than did tissues from innervated glands in response to in vitro stimulation by carbachol or isoproterenol but not in response to PDBu or forskolin. Microscopy showed that the acinar cells that had undergone sensory denervation showed a massive accumulation of secretory granules. The secretory granules filled the entire cytoplasmic space and displaced the ellipsoidal nuclei to the extreme periphery. Examination of segments of nerves revealed numerous unmyelinated axons, a few small-diameter myelinated axons, and a large amount of nerve degeneration after sensory denervation. In contrast to the effects of sensory denervation, sympathetic denervation did not alter either the acinar appearance or secretory responsiveness of the gland. Loss of the considerable sensory innervation from the trigeminal ganglion has pronounced effects on the pharmacologic responsiveness and the structure of the lacrimal gland. The effects of sensory innervation on the gland may be mediated through two possible pathways: direct input to the gland or control of the preganglionic parasympathetic pathway.

Novel Hg2+-Induced Nephropathy in Rats and Mice Lacking Mrp2: Evidence of Axial Heterogeneity in the Handling of Hg2+ Along the Proximal Tubule

PubMed Central

Zalups, Rudolfs K.; Joshee, Lucy; Bridges, Christy C.

2014-01-01

The role of the multi-resistance protein 2 (Mrp2) in the nephropathy induced by inorganic mercuric mercury (Hg2+) was studied in rats (TR−) and mice (Mrp2−/−), which lack functional Mrp2, and control animals. Animals were exposed to nephrotoxic doses of HgCl2. Forty-eight or 24 hours after exposure, tissues were harvested and analyzed for Hg content and markers of injury. Histological analyses revealed that the proximal tubular segments affected pathologically by Hg2+ were significantly different between Mrp2-deficient animals and controls. In the absence of Mrp2, cellular injury localized almost exclusively in proximal tubular segments in the subcapsular (S1) to midcortical regions (early S2) of the kidney. In control animals, cellular death occurred mainly in the proximal tubular segments in the inner cortex (late S2) and outer stripe of the outer medulla (S3). These differences in renal pathology indicate that axial heterogeneity exists along the proximal tubule with respect to how mercuric ions are handled. Total renal and hepatic accumulation of mercury was also greater in animals lacking Mrp2 than in controls, indicating that Mrp2 normally plays a significant role in eliminating mercuric ions from within proximal tubular cells and hepatocytes. Analyses of plasma creatinine, BUN, and renal expression of Kim-1 and Ngal tend to support the severity of the nephropathies detected histologically. Collectively, our findings indicate that a fraction of mercuric ions is normally secreted by Mrp2 in early portions of proximal tubules into the lumen and then is absorbed downstream in straight portions, where mercuric species typically induce toxic effects. PMID:25145654

Geology along the Fairweather-Queen Charlotte fault system off southeast Alaska and British Columbia from GLORIA images and seismic-reflection data

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bruns, T.R.; Carlson, P.R.; Stevenson, A.J.

1990-06-01

GLORIA images collected in 1989 along southeast Alaska and British Columbia strikingly show the active trace of the Fairweather-Queen Charlotte transform fault system beneath the outer shelf and slope; seismic-reflection data are used to track the fault system across the continental shelf where GLORIA data are not available. From Cross Sound to Chatham Strait, the fault system is comprised of two sets of subparallel fault traces separated by 3 to 6 km. The fault system crosses the shelf from Icy Point to south of Yakobi Valley, then follows the shelf edge to Chatham Strait. Between Chatham Strait and Dixon Entrance,more » a single, sharply defined active fault trace underlies the upper and middle slope. This fault segment is bounded on the seaward side by a high, midslope ridge and by lower slope Quaternary( ) anticlines up to 35 km wide. Southeast of Dixon Entrance, the active fault trace trends back onto the outer shelf until midway along the Queen Charlotte Islands, then cuts back to and stays at midslope to the Tuzo Wilson Knolls south of the Queen Charlotte Islands. The fault steps westward at Tuzo Wilson Knolls, which are likely part of a spreading ridge segment. Major deep-sea fans along southeast Alaska show a southeastward age progression from older to younger and record both point source deposition at Chatham Strait and Dixon Entrance and subsequent (Quaternary ) offset along the fault system. Subsidence of ocean plate now adjacent to the Chatham Strait-Dixon Entrance fault segment initiated development of both Mukluk and Horizon Channels.« less

Molecular Characterization of abLIM, a Novel Actin-binding and Double Zinc Finger Protein

PubMed Central

Roof, Dorothy J.; Hayes, Annmarie; Adamian, Michael; Chishti, Athar H.; Li, Tiansen

1997-01-01

Molecules that couple the actin-based cytoskeleton to intracellular signaling pathways are central to the processes of cellular morphogenesis and differentiation. We have characterized a novel protein, the actin-binding LIM (abLIM) protein, which could mediate such interactions between actin filaments and cytoplasmic targets. abLIM protein consists of a COOH-terminal cytoskeletal domain that is fused to an NH2-terminal domain consisting of four double zinc finger motifs. The cytoskeletal domain is ∼50% identical to erythrocyte dematin, an actin-bundling protein of the red cell membrane skeleton, while the zinc finger domains conform to the LIM motif consensus sequence. In vitro expression studies demonstrate that abLIM protein can bind to F-actin through the dematin-like domain. Transcripts corresponding to three distinct isoforms have a widespread tissue distribution. However, a polypeptide corresponding to the full-length isoform is found exclusively in the retina and is enriched in biochemical extracts of retinal rod inner segments. abLIM protein also undergoes extensive phosphorylation in light-adapted retinas in vivo, and its developmental expression in the retina coincides with the elaboration of photoreceptor inner and outer segments. Based on the composite primary structure of abLIM protein, actin-binding capacity, potential regulation via phosphorylation, and isoform expression pattern, we speculate that abLIM may play a general role in bridging the actin-based cytoskeleton with an array of potential LIM protein-binding partners. The developmental time course of abLIM expression in the retina suggests that the retina-specific isoform may have a specialized role in the development or elaboration of photoreceptor inner and outer segments. PMID:9245787

Interaction of Arrestin with Enolase1 in Photoreceptors

PubMed Central

Bolch, Susan; Dugger, Donald R.; Li, Jian; Esquenazi, Isi; Arendt, Anatol; Benzenhafer, Del; McDowell, J. Hugh

2011-01-01

Purpose. Arrestin is in disequilibrium in photoreceptors, translocating between inner and outer segments in response to light. The purpose of this project was to identify the cellular component with which arrestin associates in the dark-adapted retina. Methods. Retinas were cross-linked with 2.5 mM dithiobis(succinimidylpropionate) (DSP), and arrestin-containing complexes purified by anion-exchange chromatography. Tandem mass spectrometric analysis was used to identify the protein components in the complex. Enolase localization in photoreceptors was assessed by immunohistochemistry. Confirmation of interacting components was performed using immunoprecipitation and surface plasmon resonance (SPR). Enolase activity was also assessed in the presence of arrestin1. Results. In retinas treated with DSP, arrestin cross-linked in a 125-kDa complex. The principal components of this complex were arrestin1 and enolase1. Both arrestin1 and -4 were pulled down with enolase1 when enolase1 was immunoprecipitated. In the dark-adapted retina, enolase1 co-localized with arrestin1 in the inner segments and outer nuclear layer, but remained in the inner segments when arrestin1 translocated in response to light adaptation. SPR of purified arrestin1 and enolase1 demonstrated direct binding between arrestin1 and enolase1. Arrestin1 modulated the catalytic activity of enolase1, slowing it by as much as 24%. Conclusions. The results show that in the dark-adapted retina, arrestin1 and -4 interact with enolase1. The SPR data show that the interaction between arrestin1 and enolase1 was direct, not requiring a third element to form the complex. Arrestin1 slowed the catalytic activity of enolase1, suggesting that light-driven translocation of arrestin1 may modulate the metabolic activity of photoreceptors. PMID:21051714

Interaction of arrestin with enolase1 in photoreceptors.

PubMed

Smith, W Clay; Bolch, Susan; Dugger, Donald R; Li, Jian; Esquenazi, Isi; Arendt, Anatol; Benzenhafer, Del; McDowell, J Hugh

2011-03-01

Arrestin is in disequilibrium in photoreceptors, translocating between inner and outer segments in response to light. The purpose of this project was to identify the cellular component with which arrestin associates in the dark-adapted retina. Retinas were cross-linked with 2.5 mM dithiobis(succinimidylpropionate) (DSP), and arrestin-containing complexes purified by anion-exchange chromatography. Tandem mass spectrometric analysis was used to identify the protein components in the complex. Enolase localization in photoreceptors was assessed by immunohistochemistry. Confirmation of interacting components was performed using immunoprecipitation and surface plasmon resonance (SPR). Enolase activity was also assessed in the presence of arrestin1. In retinas treated with DSP, arrestin cross-linked in a 125-kDa complex. The principal components of this complex were arrestin1 and enolase1. Both arrestin1 and -4 were pulled down with enolase1 when enolase1 was immunoprecipitated. In the dark-adapted retina, enolase1 co-localized with arrestin1 in the inner segments and outer nuclear layer, but remained in the inner segments when arrestin1 translocated in response to light adaptation. SPR of purified arrestin1 and enolase1 demonstrated direct binding between arrestin1 and enolase1. Arrestin1 modulated the catalytic activity of enolase1, slowing it by as much as 24%. The results show that in the dark-adapted retina, arrestin1 and -4 interact with enolase1. The SPR data show that the interaction between arrestin1 and enolase1 was direct, not requiring a third element to form the complex. Arrestin1 slowed the catalytic activity of enolase1, suggesting that light-driven translocation of arrestin1 may modulate the metabolic activity of photoreceptors.

Multiple Transmitter Receptors in Regions and Layers of the Human Cerebral Cortex

PubMed Central

Zilles, Karl; Palomero-Gallagher, Nicola

2017-01-01

We measured the densities (fmol/mg protein) of 15 different receptors of various transmitter systems in the supragranular, granular and infragranular strata of 44 areas of visual, somatosensory, auditory and multimodal association systems of the human cerebral cortex. Receptor densities were obtained after labeling of the receptors using quantitative in vitro receptor autoradiography in human postmortem brains. The mean density of each receptor type over all cortical layers and of each of the three major strata varies between cortical regions. In a single cortical area, the multi-receptor fingerprints of its strata (i.e., polar plots, each visualizing the densities of multiple different receptor types in supragranular, granular or infragranular layers of the same cortical area) differ in shape and size indicating regional and laminar specific balances between the receptors. Furthermore, the three strata are clearly segregated into well definable clusters by their receptor fingerprints. Fingerprints of different cortical areas systematically vary between functional networks, and with the hierarchical levels within sensory systems. Primary sensory areas are clearly separated from all other cortical areas particularly by their very high muscarinic M2 and nicotinic α4β2 receptor densities, and to a lesser degree also by noradrenergic α2 and serotonergic 5-HT2 receptors. Early visual areas of the dorsal and ventral streams are segregated by their multi-receptor fingerprints. The results are discussed on the background of functional segregation, cortical hierarchies, microstructural types, and the horizontal (layers) and vertical (columns) organization in the cerebral cortex. We conclude that a cortical column is composed of segments, which can be assigned to the cortical strata. The segments differ by their patterns of multi-receptor balances, indicating different layer-specific signal processing mechanisms. Additionally, the differences between the strata-and area-specific fingerprints of the 44 areas reflect the segregation of the cerebral cortex into functionally and topographically definable groups of cortical areas (visual, auditory, somatosensory, limbic, motor), and reveals their hierarchical position (primary and unimodal (early) sensory to higher sensory and finally to multimodal association areas). Highlights Densities of transmitter receptors vary between areas of human cerebral cortex.Multi-receptor fingerprints segregate cortical layers.The densities of all examined receptor types together reach highest values in the supragranular stratum of all areas.The lowest values are found in the infragranular stratum.Multi-receptor fingerprints of entire areas and their layers segregate functional systemsCortical types (primary sensory, motor, multimodal association) differ in their receptor fingerprints. PMID:28970785

Histological features of the gastrointestinal tract of wild Indonesian shortfin eel, Anguilla bicolor bicolor (McClelland, 1844), captured in Peninsular Malaysia.

PubMed

Nasruddin, Nurrul Shaqinah; Azmai, Mohammad Noor Amal; Ismail, Ahmad; Saad, Mohd Zamri; Daud, Hassan Mohd; Zulkifli, Syaizwan Zahmir

2014-01-01

This study was conducted to record the histological features of the gastrointestinal tract of wild Indonesian shortfin eel, Anguilla bicolor bicolor (McClelland, 1844), captured in Peninsular Malaysia. The gastrointestinal tract was segmented into the oesophagus, stomach, and intestine. Then, the oesophagus was divided into five (first to fifth), the stomach into two (cardiac and pyloric), and the intestine into four segments (anterior, intermediate, posterior, and rectum) for histological examinations. The stomach had significantly taller villi and thicker inner circular muscles compared to the intestine and oesophagus. The lamina propria was thickest in stomach, significantly when compared with oesophagus, but not with the intestine. However, the intestine showed significantly thicker outer longitudinal muscle while gastric glands were observed only in the stomach. The histological features were closely associated with the functions of the different segments of the gastrointestinal tract. In conclusion, the histological features of the gastrointestinal tract of A. b. bicolor are consistent with the feeding habit of a carnivorous fish.

Manufacture of a 1.7m prototype of the GMT primary mirror segments

NASA Astrophysics Data System (ADS)

Martin, H. M.; Burge, J. H.; Miller, S. M.; Smith, B. K.; Zehnder, R.; Zhao, C.

2006-06-01

We have nearly completed the manufacture of a 1.7 m off-axis mirror as part of the technology development for the Giant Magellan Telescope. The mirror is an off-axis section of a 5.3 m f/0.73 parent paraboloid, making it roughly a 1:5 model of the outer 8.4 m GMT segment. The 1.7 m mirror will be the primary mirror of the New Solar Telescope at Big Bear Solar Observatory. It has a 2.7 mm peak-to-valley departure from the best-fit sphere, presenting a serious challenge in terms of both polishing and measurement. The mirror was polished with a stressed lap, which bends actively to match the local curvature at each point on the mirror surface, and works for asymmetric mirrors as well as symmetric aspheres. It was measured using a hybrid reflective-diffractive null corrector to compensate for the mirror's asphericity. Both techniques will be applied in scaled-up versions to the GMT segments.

Changes in Inner and Outer Retinal Layer Thicknesses after Vitrectomy for Idiopathic Macular Hole: Implications for Visual Prognosis

PubMed Central

Hashimoto, Yuki; Saito, Wataru; Fujiya, Akio; Yoshizawa, Chikako; Hirooka, Kiriko; Mori, Shohei; Noda, Kousuke; Ishida, Susumu

2015-01-01

Purpose To investigate sequential post-operative thickness changes in inner and outer retinal layers in eyes with an idiopathic macular hole (MH). Methods Retrospective case series. Twenty-four eyes of 23 patients who had received pars plana vitrectomy (PPV) for the closure of MH were included in the study. Spectral domain optical coherence tomography C-scan was used to automatically measure the mean thickness of the inner and outer retinal layers pre-operatively and up to 6 months following surgery. The photoreceptor outer segment (PROS) length was measured manually and was used to assess its relationship with best-corrected visual acuity (BCVA). Results Compared with the pre-operative thickness, the inner layers significantly thinned during follow-up (P = 0.02), particularly in the parafoveal (P = 0.01), but not perifoveal, area. The post-operative inner layer thinning ranged from the ganglion cell layer to the inner plexiform layer (P = 0.002), whereas the nerve fiber layer was unaltered. Outer layer thickness was significantly greater post-operatively (P = 0.002), and especially the PROS lengthened not only in the fovea but also in the parafovea (P < 0.001). Six months after surgery, BCVA was significantly correlated exclusively with the elongated foveal PROS (R = 0.42, P = 0.03), but not with any of the other thickness parameters examined. Conclusions Following PPV for MH, retinal inner layers other than the nerve fiber layer thinned, suggestive of subclinical thickening in the inner layers where no cyst was evident pre-operatively. In contrast, retinal outer layer thickness significantly increased, potentially as a result of PROS elongation linking tightly with favorable visual prognosis in MH eyes. PMID:26291526

In vivo and in vitro heterogeneity of segment length changes in the semimembranosus muscle of the toad

PubMed Central

Ahn, A N; Monti, R J; Biewener, A A

2003-01-01

Many studies examine sarcomere dynamics in single fibres or length–tension dynamics in whole muscles in vivo or in vitro, but few studies link the various levels of organisation. To relate data addressing in vitro muscle segment behaviour with in vivo whole muscle behaviour during locomotion, we measured in vivo strain patterns of muscle segments using three sonomicrometry crystals implanted along a fascicle of the semimembranosus muscle in the American toad (Bufo americanus; n = 6) during hopping. The centre crystal emitted an ultrasonic signal, while the outer crystals received the signal allowing the instantaneous measurement of lengths from two adjacent muscle segments. On the first day, we recorded from the central and distal segments. On the second day of recordings, the most distal crystal was moved to a proximal position to record from a proximal segment and the same central segment. When the toads hopped a distance of two body lengths, the proximal and central segments strained −15.1 ± 6.1 and −14.0 ± 4.9 % (i.e. shortening), respectively. Strain of the distal segment, however, was significantly lower and more variable in pattern, often lengthening before shortening during a hop. From rest length, the distal segment initially lengthened by 2.6 ± 2.0 % before shortening by 6.5 ± 3.2 % at the same hop distance. Under in vitro conditions, the central segment always shortened more than the distal segment, except when passively cycled, during which the segments strained similarly. When the whole muscle was cycled sinusoidally and stimulated phasically in vitro, the two adjacent segments strained in opposite directions over much (up to 34 %) of the cycle. These differences in strain amplitude and direction imply that two adjacent segments can not only produce and/or absorb varying amounts of mechanical energy, but can also operate on different regions of their force–length and force–velocity relationships when activated by the same neural signal. Understanding regional differences in contractile dynamics within muscles is therefore important to linking our understanding of sarcomere behaviour with whole muscle behaviour during locomotion. PMID:12717006

Specialization and integration of functional thalamocortical connectivity in the human infant.

PubMed

Toulmin, Hilary; Beckmann, Christian F; O'Muircheartaigh, Jonathan; Ball, Gareth; Nongena, Pumza; Makropoulos, Antonios; Ederies, Ashraf; Counsell, Serena J; Kennea, Nigel; Arichi, Tomoki; Tusor, Nora; Rutherford, Mary A; Azzopardi, Denis; Gonzalez-Cinca, Nuria; Hajnal, Joseph V; Edwards, A David

2015-05-19

Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions.

Specialization and integration of functional thalamocortical connectivity in the human infant

PubMed Central

Toulmin, Hilary; Beckmann, Christian F.; O'Muircheartaigh, Jonathan; Ball, Gareth; Nongena, Pumza; Makropoulos, Antonios; Ederies, Ashraf; Counsell, Serena J.; Kennea, Nigel; Arichi, Tomoki; Tusor, Nora; Rutherford, Mary A.; Azzopardi, Denis; Gonzalez-Cinca, Nuria; Hajnal, Joseph V.; Edwards, A. David

2015-01-01

Connections between the thalamus and cortex develop rapidly before birth, and aberrant cerebral maturation during this period may underlie a number of neurodevelopmental disorders. To define functional thalamocortical connectivity at the normal time of birth, we used functional MRI (fMRI) to measure blood oxygen level-dependent (BOLD) signals in 66 infants, 47 of whom were at high risk of neurocognitive impairment because of birth before 33 wk of gestation and 19 of whom were term infants. We segmented the thalamus based on correlation with functionally defined cortical components using independent component analysis (ICA) and seed-based correlations. After parcellating the cortex using ICA and segmenting the thalamus based on dominant connections with cortical parcellations, we observed a near-facsimile of the adult functional parcellation. Additional analysis revealed that BOLD signal in heteromodal association cortex typically had more widespread and overlapping thalamic representations than primary sensory cortex. Notably, more extreme prematurity was associated with increased functional connectivity between thalamus and lateral primary sensory cortex but reduced connectivity between thalamus and cortex in the prefrontal, insular and anterior cingulate regions. This work suggests that, in early infancy, functional integration through thalamocortical connections depends on significant functional overlap in the topographic organization of the thalamus and that the experience of premature extrauterine life modulates network development, altering the maturation of networks thought to support salience, executive, integrative, and cognitive functions. PMID:25941391

Interleukin-1beta-induced airway hyperresponsiveness enhances substance P in intrinsic neurons of ferret airway.

PubMed

Wu, Z-X; Satterfield, B E; Fedan, J S; Dey, R D

2002-11-01

Interleukin (IL)-1beta causes airway inflammation, enhances airway smooth muscle responsiveness, and alters neurotransmitter expression in sensory, sympathetic, and myenteric neurons. This study examines the role of intrinsic airway neurons in airway hyperresponsiveness (AHR) induced by IL-1beta. Ferrets were instilled intratracheally with IL-1beta (0.3 microg/0.3 ml) or saline (0.3 ml) once daily for 5 days. Tracheal smooth muscle contractility in vitro and substance P (SP) expression in tracheal neurons were assessed. Tracheal smooth muscle reactivity to acetylcholine (ACh) and methacholine (MCh) and smooth muscle contractions to electric field stimulation (EFS) both increased after IL-1beta. The IL-1beta-induced AHR was maintained in tracheal segments cultured for 24 h, a procedure that depletes SP from sensory nerves while maintaining viability of intrinsic airway neurons. Pretreatment with CP-99994, an antagonist of neurokinin 1 receptor, attenuated the IL-1beta-induced hyperreactivity to ACh and MCh and to EFS in cultured tracheal segments. SP-containing neurons in longitudinal trunk, SP innervation of superficial muscular plexus neurons, and SP nerve fiber density in tracheal smooth muscle all increased after treatment with IL-1beta. These results show that IL-1beta-enhanced cholinergic airway smooth muscle contractile responses are mediated by the actions of SP released from intrinsic airway neurons.

Optimization of Soft Tissue Management, Spacer Design, and Grafting Strategies for Large Segmental Bone Defects using the Chronic Caprine Tibial Defect Model

DTIC Science & Technology

2015-10-01

Several target genes such as Oct4, Sox2, TGFB, and Col1A1 were generally up-regulated in all sections. In distal sections, VWF, PDGFB, and EGFR were...TGFB, and Col1A1 in all sections. No significant main effects were found for target gene fold-change between outer or inner membrane position or distal

Optimization of GaAs Nanowire Pin Junction Array Solar Cells by Using AlGaAs/GaAs Heterojunctions

NASA Astrophysics Data System (ADS)

Wu, Yao; Yan, Xin; Wei, Wei; Zhang, Jinnan; Zhang, Xia; Ren, Xiaomin

2018-04-01

We optimized the performance of GaAs nanowire pin junction array solar cells by introducing AlGaAs/GaAs heterejunctions. AlGaAs is used for the p type top segment for axial junctions and the p type outer shell for radial junctions. The AlGaAs not only serves as passivation layers for GaAs nanowires but also confines the optical generation in the active regions, reducing the recombination loss in heavily doped regions and the minority carrier recombination at the top contact. The results show that the conversion efficiency of GaAs nanowires can be greatly enhanced by using AlGaAs for the p segment instead of GaAs. A maximum efficiency enhancement of 8.42% has been achieved in this study. And for axial nanowire, by using AlGaAs for the top p segment, a relatively long top segment can be employed without degenerating device performance, which could facilitate the fabrication and contacting of nanowire array solar cells. While for radial nanowires, AlGaAs/GaAs nanowires show better tolerance to p-shell thickness and surface condition.

Optimization of GaAs Nanowire Pin Junction Array Solar Cells by Using AlGaAs/GaAs Heterojunctions.

PubMed

Wu, Yao; Yan, Xin; Wei, Wei; Zhang, Jinnan; Zhang, Xia; Ren, Xiaomin

2018-04-25

We optimized the performance of GaAs nanowire pin junction array solar cells by introducing AlGaAs/GaAs heterejunctions. AlGaAs is used for the p type top segment for axial junctions and the p type outer shell for radial junctions. The AlGaAs not only serves as passivation layers for GaAs nanowires but also confines the optical generation in the active regions, reducing the recombination loss in heavily doped regions and the minority carrier recombination at the top contact. The results show that the conversion efficiency of GaAs nanowires can be greatly enhanced by using AlGaAs for the p segment instead of GaAs. A maximum efficiency enhancement of 8.42% has been achieved in this study. And for axial nanowire, by using AlGaAs for the top p segment, a relatively long top segment can be employed without degenerating device performance, which could facilitate the fabrication and contacting of nanowire array solar cells. While for radial nanowires, AlGaAs/GaAs nanowires show better tolerance to p-shell thickness and surface condition.

Reciprocal synapses between outer hair cells and their afferent terminals: evidence for a local neural network in the mammalian cochlea.

PubMed

Thiers, Fabio A; Nadol, Joseph B; Liberman, M Charles

2008-12-01

Cochlear outer hair cells (OHCs) serve both as sensory receptors and biological motors. Their sensory function is poorly understood because their afferent innervation, the type-II spiral ganglion cell, has small unmyelinated axons and constitutes only 5% of the cochlear nerve. Reciprocal synapses between OHCs and their type-II terminals, consisting of paired afferent and efferent specialization, have been described in the primate cochlea. Here, we use serial and semi-serial-section transmission electron microscopy to quantify the nature and number of synaptic interactions in the OHC area of adult cats. Reciprocal synapses were found in all OHC rows and all cochlear frequency regions. They were more common among third-row OHCs and in the apical half of the cochlea, where 86% of synapses were reciprocal. The relative frequency of reciprocal synapses was unchanged following surgical transection of the olivocochlear bundle in one cat, confirming that reciprocal synapses were not formed by efferent fibers. In the normal ear, axo-dendritic synapses between olivocochlear terminals and type-II terminals and/or dendrites were as common as synapses between olivocochlear terminals and OHCs, especially in the first row, where, on average, almost 30 such synapses were seen in the region under a single OHC. The results suggest that a complex local neuronal circuitry in the OHC area, formed by the dendrites of type-II neurons and modulated by the olivocochlear system, may be a fundamental property of the mammalian cochlea, rather than a curiosity of the primate ear. This network may mediate local feedback control of, and bidirectional communication among, OHCs throughout the cochlear spiral.

Tagmatization in Stomatopoda - reconsidering functional units of modern-day mantis shrimps (Verunipeltata, Hoplocarida) and implications for the interpretation of fossils.

PubMed

Haug, Carolin; Sallam, Wafaa S; Maas, Andreas; Waloszek, Dieter; Kutschera, Verena; Haug, Joachim T

2012-11-14

We describe the tagmatization pattern of the anterior region of the extant stomatopod Erugosquilla massavensis. For documentation we used the autofluorescence capacities of the specimens, resulting in a significant contrast between sclerotized and membranous areas. The anterior body region of E. massavensis can be grouped into three tagmata. Tagma I, the sensorial unit, comprises the segments of the eyes, antennules and antennae. This unit is set-off anteriorly from the posterior head region. Ventrally this unit surrounds a large medial sclerite, interpreted as the anterior part of the hypostome. Dorsally the antennular and antennal segments each bear a well-developed tergite. The dorsal shield is part of tagma II, most of the ventral part of which is occupied in the midline by the large, partly sclerotized posterior part of a complex combining hypostome and labrum. Tagma II includes three more segments behind the labrum, the mandibular, maxillulary and maxillary segments. Tagma III includes the maxillipedal segments, bearing five pairs of sub-chelate appendages. The dorsal sclerite of the first of these tagma-III segments, the segment of the first maxillipeds, is not included in the shield, so this segment is not part of tagma II as generally thought. The second and third segments of tagma III form a unit dorsally and ventrally. The tergites of the segments of tagma III become progressively larger from the anterior to the posterior, possibly resulting from a paedomorphic effect during evolution, which caused this reversed enlargement. The described pattern of tagmosis differs from current textbook knowledge. Therefore, our re-description of the anterior body area of stomatopods is of considerable impact for understanding the head evolution of Stomatopoda. Likewise, it has a bearing upon any comparisons with fossil stomatopods, as mainly sclerotized areas are fossilized, and, on a wider scale, upon larger-scale comparisons with other malacostracans and eucrustaceans in general.

Effects of Nerve Injury and Segmental Regeneration on the Cellular Correlates of Neural Morphallaxis

PubMed Central

Martinez, Veronica G.; Manson, Josiah M.B.; Zoran, Mark J.

2009-01-01

Functional recovery of neural networks after injury requires a series of signaling events similar to the embryonic processes that governed initial network construction. Neural morphallaxis, a form of nervous system regeneration, involves reorganization of adult neural connectivity patterns. Neural morphallaxis in the worm, Lumbriculus variegatus, occurs during asexual reproduction and segmental regeneration, as body fragments acquire new positional identities along the anterior–posterior axis. Ectopic head (EH) formation, induced by ventral nerve cord lesion, generated morphallactic plasticity including the reorganization of interneuronal sensory fields and the induction of a molecular marker of neural morphallaxis. Morphallactic changes occurred only in segments posterior to an EH. Neither EH formation, nor neural morphallaxis was observed after dorsal body lesions, indicating a role for nerve cord injury in morphallaxis induction. Furthermore, a hierarchical system of neurobehavioral control was observed, where anterior heads were dominant and an EH controlled body movements only in the absence of the anterior head. Both suppression of segmental regeneration and blockade of asexual fission, after treatment with boric acid, disrupted the maintenance of neural morphallaxis, but did not block its induction. Therefore, segmental regeneration (i.e., epimorphosis) may not be required for the induction of morphallactic remodeling of neural networks. However, on-going epimorphosis appears necessary for the long-term consolidation of cellular and molecular mechanisms underlying the morphallaxis of neural circuitry. PMID:18561185

The Role of Sensory Perception, Emotionality and Lifeworld in Auditory Word Processing: Evidence from Congenital Blindness and Synesthesia.

PubMed

Papadopoulos, Judith; Domahs, Frank; Kauschke, Christina

2017-12-01

Although it has been established that human beings process concrete and abstract words differently, it is still a matter of debate what factors contribute to this difference. Since concrete concepts are closely tied to sensory perception, perceptual experience seems to play an important role in their processing. The present study investigated the processing of nouns during an auditory lexical decision task. Participants came from three populations differing in their visual-perceptual experience: congenitally blind persons, word-color synesthetes, and sighted non-synesthetes. Specifically, three features with potential relevance to concreteness were manipulated: sensory perception, emotionality, and Husserlian lifeworld, a concept related to the inner versus the outer world of the self. In addition to a classical concreteness effect, our results revealed a significant effect of lifeworld: words that are closely linked to the internal states of humans were processed faster than words referring to the outside world. When lifeworld was introduced as predictor, there was no effect of emotionality. Concerning participants' perceptual experience, an interaction between participant group and item characteristics was found: the effects of both concreteness and lifeworld were more pronounced for blind compared to sighted participants. We will discuss the results in the context of embodied semantics, and we will propose an approach to concreteness based on the individual's bodily experience and the relatedness of a given concept to the self.

Major advances in testing of dairy products: milk component and dairy product attribute testing.

PubMed

Barbano, D M; Lynch, J M

2006-04-01

Milk component analysis is relatively unusual in the field of quantitative analytical chemistry because an analytical test result determines the allocation of very large amounts of money between buyers and sellers of milk. Therefore, there is high incentive to develop and refine these methods to achieve a level of analytical performance rarely demanded of most methods or laboratory staff working in analytical chemistry. In the last 25 yr, well-defined statistical methods to characterize and validate analytical method performance combined with significant improvements in both the chemical and instrumental methods have allowed achievement of improved analytical performance for payment testing. A shift from marketing commodity dairy products to the development, manufacture, and marketing of value added dairy foods for specific market segments has created a need for instrumental and sensory approaches and quantitative data to support product development and marketing. Bringing together sensory data from quantitative descriptive analysis and analytical data from gas chromatography olfactometry for identification of odor-active compounds in complex natural dairy foods has enabled the sensory scientist and analytical chemist to work together to improve the consistency and quality of dairy food flavors.

Absolute measurements of large mirrors

NASA Astrophysics Data System (ADS)

Su, Peng

The ability to produce mirrors for large astronomical telescopes is limited by the accuracy of the systems used to test the surfaces of such mirrors. Typically the mirror surfaces are measured by comparing their actual shapes to a precision master, which may be created using combinations of mirrors, lenses, and holograms. The work presented here develops several optical testing techniques that do not rely on a large or expensive precision, master reference surface. In a sense these techniques provide absolute optical testing. The Giant Magellan Telescope (GMT) has been designed with a 350 m 2 collecting area provided by a 25 m diameter primary mirror made out from seven circular independent mirror segments. These segments create an equivalent f/0.7 paraboloidal primary mirror consisting of a central segment and six outer segments. Each of the outer segments is 8.4 m in diameter and has an off-axis aspheric shape departing 14.5 mm from the best-fitting sphere. Much of the work in this dissertation is motivated by the need to measure the surfaces or such large mirrors accurately, without relying on a large or expensive precision reference surface. One method for absolute testing describing in this dissertation uses multiple measurements relative to a reference surface that is located in different positions with respect to the test surface of interest. The test measurements are performed with an algorithm that is based on the maximum likelihood (ML) method. Some methodologies for measuring large flat surfaces in the 2 m diameter range and for measuring the GMT primary mirror segments were specifically developed. For example, the optical figure of a 1.6-m flat mirror was determined to 2 nm rms accuracy using multiple 1-meter sub-aperture measurements. The optical figure of the reference surface used in the 1-meter sub-aperture measurements was also determined to the 2 nm level. The optical test methodology for a 1.7-m off axis parabola was evaluated by moving several times the mirror under test in relation to the test system. The result was a separation of errors in the optical test system to those errors from the mirror under test. This method proved to be accurate to 12nm rms. Another absolute measurement technique discussed in this dissertation utilizes the property of a paraboloidal surface of reflecting rays parallel to its optical axis, to its focal point. We have developed a scanning pentaprism technique that exploits this geometry to measure off-axis paraboloidal mirrors such as the GMT segments. This technique was demonstrated on a 1.7 m diameter prototype and proved to have a precision of about 50 nm rms.

Role of Geologic Framework, Paleotopography, Sediment Supply, and Human Modification in the Evolutionary Development of the Northeastern North Carolina Barrier Island System

NASA Astrophysics Data System (ADS)

Riggs, S. R.; Thieler, E. R.; Mallinson, D. A.; Culver, S. J.; Corbett, D. R.; Hoffman, C. W.

2002-12-01

The NE North Carolina coastal system contains an exceptionally thick and well preserved Quaternary stratigraphic record that is the focus of a five-year Cooperative Coastal Geology Program between the USGS, several academic institutions, and state agencies. The major goal is to map this Quaternary section on the inner continental shelf, Outer Banks barrier islands, Albemarle-Pamlico estuarine system, and adjacent land areas. The program objectives are to define the geologic framework, develop the detailed evolutionary history, and understand the ongoing process dynamics driving this large, complex, and rapidly changing, high-energy coastal system. Preliminary data synthesis demonstrates that the major controls dictating the present health and future evolution of this coastal system include the following. 1) The regional late Pleistocene morphology constitutes the underlying geologic framework that the Holocene system has inherited. 2) The controlling paleotopography is a series of lowstand drainage basins consisting of trunk and tributary streams and associated interstream divides that are being drowned. 3) Three major sediment sources dictate the highly variable sand resources available to specific barrier segments and include riverine channel and deltaic deposits associated with lowstand trunk streams, the large cross-shelf cape shoal sand deposits, and sand-rich units occurring within the adjacent shoreface and inner-self strata. 4) Wherever large sand supplies have historically been available, the barrier segments occur as complex islands with large sand volumes producing high and wide barriers, whereas barrier segments without adequate sand supplies are sediment starved and occur as simple overwash barriers. 5) Human modification of the barrier islands over the past seven decades represents a major force that has significantly changed the barrier island dynamics and evolution. 6) The Albemarle Embayment appears to have a slightly higher rate of sea-level rise than adjacent regions due to a slow rate of regional subsidence. Consequently, if the ongoing pattern of storm activity and sea-level rise either continues or increases during the next few decades to centuries, several simple overwash barrier segments on the Outer Banks, that are currently disintegrating, will ultimately collapse into Pamlico Sound. These barrier segments will likely back-step across the open marine Pamlico Embayment and reform on the landward side. A few sand-rich complex barrier segments will persist as isolated, but perched and eroding islands for some longer period of time. In contrast, simple overwash barrier segments that have received minimal human modification and are associated with narrow and shallow back-barrier sounds, appear to be maintaining themselves in their upward and landward migration in response to ongoing storms and sea-level rise.

The computational nature of memory modification

PubMed Central

Gershman, Samuel J; Monfils, Marie-H; Norman, Kenneth A; Niv, Yael

2017-01-01

Retrieving a memory can modify its influence on subsequent behavior. We develop a computational theory of memory modification, according to which modification of a memory trace occurs through classical associative learning, but which memory trace is eligible for modification depends on a structure learning mechanism that discovers the units of association by segmenting the stream of experience into statistically distinct clusters (latent causes). New memories are formed when the structure learning mechanism infers that a new latent cause underlies current sensory observations. By the same token, old memories are modified when old and new sensory observations are inferred to have been generated by the same latent cause. We derive this framework from probabilistic principles, and present a computational implementation. Simulations demonstrate that our model can reproduce the major experimental findings from studies of memory modification in the Pavlovian conditioning literature. DOI: http://dx.doi.org/10.7554/eLife.23763.001 PMID:28294944

Relationships between sensory evaluations of beef tenderness, shear force measurements and consumer characteristics.

PubMed

Van Wezemael, Lynn; De Smet, Stefaan; Ueland, Øydis; Verbeke, Wim

2014-07-01

The supply of tender beef is an important challenge for the beef industry. Knowledge about the profile of consumers who are more optimistic or more accurate in their tenderness evaluations is important for product development and beef marketing purposes. Central location tests of beef steaks were performed in Norway and Belgium (n=218). Instrumental and sensorial tenderness of three muscles from Belgian Blue and Norwegian Red cattle was reported. Consumers who are optimistically evaluating tenderness were found to be more often male, less food neophobic, more positive towards beef healthiness, and showed fewer concerns about beef safety. No clear profile emerged for consumers who assessed tenderness similar to shear force measurements, which suggests that tenderness is mainly evaluated subjectively. The results imply a window of opportunities in tenderness improvements, and allow targeting a market segment which is less critical towards beef tenderness. © 2013 Elsevier Ltd. All rights reserved.

A double-sided microscope to realize whole-ganglion imaging of membrane potential in the medicinal leech

PubMed Central

Wagenaar, Daniel A

2017-01-01

Studies of neuronal network emergence during sensory processing and motor control are greatly facilitated by technologies that allow us to simultaneously record the membrane potential dynamics of a large population of neurons in single cell resolution. To achieve whole-brain recording with the ability to detect both small synaptic potentials and action potentials, we developed a voltage-sensitive dye (VSD) imaging technique based on a double-sided microscope that can image two sides of a nervous system simultaneously. We applied this system to the segmental ganglia of the medicinal leech. Double-sided VSD imaging enabled simultaneous recording of membrane potential events from almost all of the identifiable neurons. Using data obtained from double-sided VSD imaging, we analyzed neuronal dynamics in both sensory processing and generation of behavior and constructed functional maps for identification of neurons contributing to these processes. PMID:28944754

Contralateral Breast Dose After Whole-Breast Irradiation: An Analysis by Treatment Technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, Terence M.; Moran, Jean M., E-mail: jmmoran@med.umich.edu; Hsu, Shu-Hui

2012-04-01

Purpose: To investigate the contralateral breast dose (CBD) across a continuum of breast-conservation therapy techniques. Methods and Materials: An anthropomorphic phantom was CT-simulated, and six treatment plans were generated: open tangents, tangents with an external wedge on the lateral beam, tangents with lateral and medial external wedges, a simple segment plan (three segments per tangent), a complex segmental intensity-modulated radiotherapy (IMRT) plan (five segments per tangent), and a beamlet IMRT plan (>100 segments). For all techniques, the breast on the phantom was irradiated to 5000 cGy. Contralateral breast dose was measured at a uniform depth at the center and eachmore » quadrant using thermoluminescent detectors. Results: Contralateral breast dose varied with position and was 50 {+-} 7.3 cGy in the inner half, 24 {+-} 4.1 cGy at the center, and 16 {+-} 2.2 cGy in the outer half for the open tangential plan. Compared with an average dose of 31 cGy across all points for the open field, the average doses were simple segment 32 cGy (range, 99-105% compared with open technique), complex segment 34 cGy (range, 103-117% compared with open technique), beamlet IMRT 34 cGy (range, 103-124% compared with open technique), lateral wedge only 46 cGy (range, 133-175% compared with open technique), and medial and lateral wedge 96 cGy (range, 282-370% compared with open technique). Conclusions: Single or dual wedge techniques resulted in the highest CBD increases compared with open tangents. To obtain the desired homogeneity to the treated breast while minimizing CBD, segmental and IMRT techniques should be encouraged over external physical compensators.« less

Transition duct system with straight ceramic liner for delivering hot-temperature gases in a combustion turbine engine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wiebe, David J.

A transition duct system (10) for delivering hot-temperature gases from a plurality of combustors in a combustion turbine engine is provided. The system includes an exit piece (16) for each combustor. The exit piece may include a straight path segment (26) for receiving a gas flow from a respective combustor. A straight ceramic liner (40) may be inwardly disposed onto a metal outer shell (38) along the straight path segment of the exit piece. Structural arrangements are provided to securely attach the ceramic liner in the presence of substantial flow path pressurization. Cost-effective serviceability of the transition duct systems ismore » realizable since the liner can be readily removed and replaced as needed.« less

Stress and strain analysis of contractions during ramp distension in partially obstructed guinea pig jejunal segments

PubMed Central

Zhao, Jingbo; Liao, Donghua; Yang, Jian; Gregersen, Hans

2011-01-01

Previous studies have demonstrated morphological and biomechanical remodeling in the intestine proximal to an obstruction. The present study aimed to obtain stress and strain thresholds to initiate contraction and the maximal contraction stress and strain in partially obstructed guinea pig jejunal segments. Partial obstruction and sham operations were surgically created in mid-jejunum of male guinea pigs. The animals survived 2, 4, 7, and 14 days, respectively. Animals not being operated on served as normal controls. The segments were used for no-load state, zero-stress state and distension analyses. The segment was inflated to 10 cmH2O pressure in an organ bath containing 37°C Krebs solution and the outer diameter change was monitored. The stress and strain at the contraction threshold and at maximum contraction were computed from the diameter, pressure and the zero-stress state data. Young’s modulus was determined at the contraction threshold. The muscle layer thickness in obstructed intestinal segments increased up to 300%. Compared with sham-obstructed and normal groups, the contraction stress threshold, the maximum contraction stress and the Young’s modulus at the contraction threshold increased whereas the strain threshold and maximum contraction strain decreased after 7 days obstruction (P<0.05 and 0.01). In conclusion, in the partially obstructed intestinal segments, a larger distension force was needed to evoke contraction likely due to tissue remodeling. Higher contraction stresses were produced and the contraction deformation (strain) became smaller. PMID:21632056

Food choice considerations among American Indians living in rural Oklahoma: The THRIVE study.

PubMed

Wetherill, Marianna S; Williams, Mary B; Hartwell, Micah L; Salvatore, Alicia L; Jacob, Tvli; Cannady, Tamela K; Standridge, Joy; Fox, Jill; Spiegel, Jennifer; Anderson, Natia; Jernigan, Valarie Blue Bird

2018-05-17

In rural American Indian (AI) communities, access to affordable, healthy foods is often limited. Understanding AI food choice considerations when selecting foods, such as sensory appeal, cost, or health, is an important yet understudied topic for eliminating persistent AI health disparities. In partnership with the Chickasaw Nation and Choctaw Nation of Oklahoma, we administered a modified version of the Food Choice Values (FCV) Questionnaire to a cross-sectional sample of 83 AI patrons shopping at tribally-owned convenience stores ≥3 times per week. The FCV Questionnaire uses 25 items to assess eight FCV subscales related to buying and eating food, including sensory appeal; safety; accessibility; convenience; health/weight control; organic; tradition; and comfort. We compared mean scores for each FCV subscale by demographic groups using t-tests and ANOVA. We used confirmatory factor analysis (CFA) to examine how well the data from this population fit FCV subscale constructs. We then used cluster analysis, MANOVA, and discriminant analysis to characterize distinct segments of the population based on patterns of FCV endorsement. Appeal, safety, and access FCVs were most strongly endorsed across the sample. Prioritization of FCVs varied by age, gender, income, and education. Our cluster analysis identified four groups, or segments, each with distinct patterns of FCV endorsement: limited endorsement of any FCVs (23.3%); safety and sensory appeal (32.9%); health/weight control (17.8%); and broad endorsement of FCVs (26.0%). These groups varied by age and employment status. Findings from this analysis informed the design and implementation of a healthy retail intervention comprised of new healthful foods and beverages, product placement and marketing strategies within four tribally-owned and operated convenience stores. Public health interventions aimed at reducing nutrition-related disparities in rural AI populations may benefit from assessing food choice considerations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dynamic synchronization of ongoing neuronal activity across spinal segments regulates sensory information flow

PubMed Central

Contreras-Hernández, E; Chávez, D; Rudomin, P

2015-01-01

Previous studies on the correlation between spontaneous cord dorsum potentials recorded in the lumbar spinal segments of anaesthetized cats suggested the operation of a population of dorsal horn neurones that modulates, in a differential manner, transmission along pathways mediating Ib non-reciprocal postsynaptic inhibition and pathways mediating primary afferent depolarization and presynaptic inhibition. In order to gain further insight into the possible neuronal mechanisms that underlie this process, we have measured changes in the correlation between the spontaneous activity of individual dorsal horn neurones and the cord dorsum potentials associated with intermittent activation of these inhibitory pathways. We found that high levels of neuronal synchronization within the dorsal horn are associated with states of incremented activity along the pathways mediating presynaptic inhibition relative to pathways mediating Ib postsynaptic inhibition. It is suggested that ongoing changes in the patterns of functional connectivity within a distributed ensemble of dorsal horn neurones play a relevant role in the state-dependent modulation of impulse transmission along inhibitory pathways, among them those involved in the central control of sensory information. This feature would allow the same neuronal network to be involved in different functional tasks. Key points We have examined, in the spinal cord of the anaesthetized cat, the relationship between ongoing correlated fluctuations of dorsal horn neuronal activity and state-dependent activation of inhibitory reflex pathways. We found that high levels of synchronization between the spontaneous activity of dorsal horn neurones occur in association with the preferential activation of spinal pathways leading to primary afferent depolarization and presynaptic inhibition relative to activation of pathways mediating Ib postsynaptic inhibition. It is suggested that changes in synchronization of ongoing activity within a distributed network of dorsal horn neurones play a relevant role in the configuration of structured (non-random) patterns of functional connectivity that shape the interaction of sensory inputs with spinal reflex pathways subserving different functional tasks. PMID:25653206

Immunocytochemical localization of the NMDA-R2A receptor subunit in the cat retina.

PubMed

Goebel, D J; Aurelia, J L; Tai, Q; Jojich, L; Poosch, M S

1998-10-19

Immunocytochemical studies were performed to determine the distribution and cellular localization of the NMDA-R2A receptor subunit (R2A) in the cat retina. R2A-immunoreactivity (R2A-IR) was noted in all layers of the retina, with specific localizations in the outer segments of red/green and blue cone photoreceptors, B-type horizontal cells, several types of amacrine cells, Müller cells and the majority of cells in the ganglion cell layer. In the inner nuclear layer, 48% of all cells residing in the amacrine cell layer were R2A-IR including a cell resembling the GABAergic A17 amacrine cell. Interestingly, the AII rod amacrine cell was devoid of R2A-IR. Although the localization of the R2A subunit was anticipated in ganglion cells, amacrines and Müller cells, the presence of this receptor subunit to the cells in the outer retina was not expected. Here, both the R2A and the R2B subunits were found to be present in the outer segments of cone photoreceptors and to the tips of rod outer segments. Although the function of these receptor subunits in rod and cone photoreceptors remains to be determined, the fact that both R2A and R2B receptor subunits are localized to cone outer segments suggests a possible alternative pathway for calcium entry into a region where this cation plays such a crucial role in the process of phototransduction. To further classify the cells that display NR2A-IR, we performed dual labeling experiments showing the relationship between R2A-labeled cells with GABA. Results showed that all GABAergic-amacrines and displaced amacrines express the R2A-subunit protein. In addition, approximately 11% of the NR2A-labeled amacrines, did not stain for GABA. These findings support pharmacological data showing that NMDA directly facilitates GABA release in retina and retinal cultures [I.L. Ferreira, C.B. Duarte, P.F. Santos, C.M. Carvalho, A.P. Carvalho, Release of [3H]GABA evoked by glutamate receptor agonist in cultured chick retinal cells: effect of Ca2+, Brain Res. 664 (1994) 252-256; G.D. Zeevalk, W.J. Nicklas, Action of the anti-ischemic agent ifenprodil on N-methyl-d-aspartate and kainate-mediated excitotoxicity, Brain Res. 522 (1990) 135-139; R. Huba, H.D. Hofmann, Transmitter-gated currents of GABAergic amacrine-like cells in chick retinal cultures, Vis. Neurosci. 6 (1991) 303-314; M. Yamashita, R. Huba, H.D. Hofmann, Early in vitro development of voltage- and transmitter-gated currents in GABAergic amacrine cells, Dev. Brain Res. 82 (1994) 95-102; R. Ientile, S. Pedale, V. Picciurro, V. Macaione, C. Fabiano, S. Macaione, Nitric oxide mediates NMDA-evoked [3H]GABA release from chick retina cells, FEBS Lett. 417 (1997) 345-348; R.C. Kubrusly, M.C. deMello, F.G. deMello, Aspartate as a selective NMDA agonist in cultured cells from the avian retina, Neurochem. Intl. 32 (1998) 47-52] or reduction of GABA in vivo [N.N. Osborn, A.J. Herrera, The effect of experimental ischaemia and excitatory amino acid agonist on the GABA and serotonin immunoreactivities in the rabbit retina, Neurosci. 59 (1994) 1071-1081]. Since the majority of GABAergic synapses in the inner retina are onto both rod and cone bipolar axon terminals [R.G. Pourcho, M.T. Owzcarzak, Distribution of GABA immunoreactivity in the cat retina: A light and electron-microscopic study, Vis. Neurosci. 2 (1989) 425-435], we hypothesize that the NMDA-receptor plays a crucial role in providing feedback inhibition onto rod and cone bipolar cells. Copyright 1998 Elsevier Science B.V.

LONG-TERM SD-OCT/SLO IMAGING OF NEURORETINA AND RETINAL PIGMENT EPITHELIUM AFTER SUB-THRESHOLD INFRARED LASER TREATMENT OF DRUSEN

PubMed Central

MOJANA, FRANCESCA; BRAR, MANPREET; CHENG, LINGYUN; BARTSCH, DIRK-UWE G.; FREEMAN, WILLIAM R.

2012-01-01

PURPOSE To determine the long-term effect of sub-threshold diode laser treatment for drusen in patients with non-exudative age-related macular degeneration (AMD) with spectral domain optical coherence tomography combined with simultaneous scanning laser ophthalmoscope (SD-OCT/SLO). METHODS 8 eyes of 4 consecutive AMD patients with bilateral drusen previously treated with sub-threshold diode laser were imaged with SD-OCT/SLO. Abnormalities in the outer retina layers reflectivity as seen with SD-OCT/SLO were retrospectively analyzed and compared with color fundus pictures and autofluorescence images (AF) acquired immediately before and after the laser treatment. RESULTS A focal discrete disruptions in the reflectivity of the outer retinal layers was noted in 29% of the laser lesions. The junction in between the inner and outer segment of the photoreceptor was more frequently affected, with associated focal damage of the outer nuclear layer. Defects of the RPE were occasionally detected. These changes did not correspond to threshold burns on color fundus photography, but corresponded to focal areas of increased AF in the majority of the cases. CONCLUSIONS Sub-threshold diode laser treatment causes long-term disruption of the retinal photoreceptor layer as analyzed by SD-OCT/SLO. The concept that sub-threshold laser treatment can achieve a selected RPE effect without damage to rods and cones may be flawed. PMID:21157398

Accurate quantification of local changes for carotid arteries in 3D ultrasound images using convex optimization-based deformable registration

NASA Astrophysics Data System (ADS)

Cheng, Jieyu; Qiu, Wu; Yuan, Jing; Fenster, Aaron; Chiu, Bernard

2016-03-01

Registration of longitudinally acquired 3D ultrasound (US) images plays an important role in monitoring and quantifying progression/regression of carotid atherosclerosis. We introduce an image-based non-rigid registration algorithm to align the baseline 3D carotid US with longitudinal images acquired over several follow-up time points. This algorithm minimizes the sum of absolute intensity differences (SAD) under a variational optical-flow perspective within a multi-scale optimization framework to capture local and global deformations. Outer wall and lumen were segmented manually on each image, and the performance of the registration algorithm was quantified by Dice similarity coefficient (DSC) and mean absolute distance (MAD) of the outer wall and lumen surfaces after registration. In this study, images for 5 subjects were registered initially by rigid registration, followed by the proposed algorithm. Mean DSC generated by the proposed algorithm was 79:3+/-3:8% for lumen and 85:9+/-4:0% for outer wall, compared to 73:9+/-3:4% and 84:7+/-3:2% generated by rigid registration. Mean MAD of 0:46+/-0:08mm and 0:52+/-0:13mm were generated for lumen and outer wall respectively by the proposed algorithm, compared to 0:55+/-0:08mm and 0:54+/-0:11mm generated by rigid registration. The mean registration time of our method per image pair was 143+/-23s.

Scene analysis for a breadboard Mars robot functioning in an indoor environment

NASA Technical Reports Server (NTRS)

Levine, M. D.

1973-01-01

The problem is delt with of computer perception in an indoor laboratory environment containing rocks of various sizes. The sensory data processing is required for the NASA/JPL breadboard mobile robot that is a test system for an adaptive variably-autonomous vehicle that will conduct scientific explorations on the surface of Mars. Scene analysis is discussed in terms of object segmentation followed by feature extraction, which results in a representation of the scene in the robot's world model.