Self-consistent radial sheath

International Nuclear Information System (INIS)

Hazeltine, R.D.

1988-12-01

The boundary layer arising in the radial vicinity of a tokamak limiter is examined, with special reference to the TEXT tokamak. It is shown that sheath structure depends upon the self-consistent effects of ion guiding-center orbit modification, as well as the radial variation of E /times/ B-induced toroidal rotation. Reasonable agreement with experiment is obtained from an idealized model which, however simplified, preserves such self-consistent effects. It is argued that the radial sheath, which occurs whenever confining magnetic field-lines lie in the plasma boundary surface, is an object of some intrinsic interest. It differs from the more familiar axial sheath because magnetized charges respond very differently to parallel and perpendicular electric fields. 11 refs., 1 fig

Ultrasound diagnosis of rectus sheath hematoma

International Nuclear Information System (INIS)

Hwang, M. S.; Chang, J. C.; Rhee, C. B.

1984-01-01

6 cases of rectus sheath hematoma were correctly diagnosed by ultrasound. 2 cases had bilateral rectus sheath hematoma and 4 cases were unilateral. On ultrasound finding, relatively well defined oval or spindle like cystic mass situated in the area of rectus muscle on all cases. Ultrasound examination may give more definite diagnosis and extension rectus sheath hematoma and also helpful to follow up study of hematoma

The stem and leaf super green mutant induced by 60Co γ-rays irradiation

International Nuclear Information System (INIS)

Wei Yubo; Liang Naiting; Buhaliqiem; Zhang Yinbao

2003-01-01

Super green gene mutant was developed from population of M 2 generation after the dry seeds of rice Huazhiwu from Japan with good quality and resistance to cold had been irradiated with 50 Gy 60 Co γ-ray. The leaf, sheath, panicle axis and petiole of mutant was characterized by deeply green, and did not turn yellow after maturing date. The chlorophyll content in straw is 2.2 times higher than that in common straw. The results of raising livestock showed that horse, donkey and sheep had evident selectivity to the green straw

Sheath insulator final test report, TFE Verification Program

Energy Technology Data Exchange (ETDEWEB)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications.

Sheath insulator final test report, TFE Verification Program

International Nuclear Information System (INIS)

1994-07-01

The sheath insulator in a thermionic cell has two functions. First, the sheath insulator must electrically isolate the collector form the outer containment sheath tube that is in contact with the reactor liquid metal coolant. Second, The sheath insulator must provide for high uniform thermal conductance between the collector and the reactor coolant to remove away waste heat. The goals of the sheath insulator test program were to demonstrate that suitable ceramic materials and fabrication processes were available, and to validate the performance of the sheath insulator for TFE-VP requirements. This report discusses the objectives of the test program, fabrication development, ex-reactor test program, in-reactor test program, and the insulator seal specifications

Plasma sheath criterion in thermal electronegative plasmas

International Nuclear Information System (INIS)

Ghomi, Hamid; Khoramabadi, Mansour; Ghorannevis, Mahmod; Shukla, Padma Kant

2010-01-01

The sheath formation criterion in electronegative plasma is examined. By using a multifluid model, it is shown that in a collisional sheath there will be upper as well as lower limits for the sheath velocity criterion. However, the parameters of the negative ions only affect the lower limit.

Inheritance of the narrow leaf mutation in Pea (Pisum Sativum L.)

International Nuclear Information System (INIS)

Naidenova, N.; Vassilevska-Ivanova, R.

2006-01-01

Three pea mutant lines 2/111, 2/174 and 3/106 with reduced narrow oblong leaves were produced after gamma irradiation. They were characterized morphologically and for seed productivity elements. The size and shape of the stipules and the leaflets were evaluated by L/W (length/width) indices. Reciprocal crosses between mutants and normal plants were executed, and F1, F2 generations were analysed. It was established that mutants 2/111 and 3/106 have intermediate inheritance and they are allelic with each other; mutant 2/174 revealed single-gene recessive inheritance with deficiency of mutant plants. It was concluded that 2/174 was not allelic with 2/111 and 3/106. Mutants 2/111 and 3/106 exhibited a phenotype similar to previously described mutant fom (folium oblongum). Allelic test between the new mutants and these described previously was not performed. The reported here lines are utilized to increase understanding of the control of leaf development in pea. (authors)

Stability of the plasma sheath

International Nuclear Information System (INIS)

Franklin, R.N.

1979-12-01

The stability of a collisionless sheath joined to a plasma in the presence of secondary emission of electrons from the sheath boundary is examined in the fluid approximation. Instability is unlikely to occur under floating conditions but if significant currents flow corresponding to increased wall-plasma potentials the system can go unstable. (author)

Spectrum of mutant characters utilized in developing improved cultivars

International Nuclear Information System (INIS)

Donini, B.; Kawai, T.; Micke, A.

1984-01-01

Although about 500 cultivars are known to have been developed by using induced mutations, the range of mutant traits seems to be rather narrow. Mutant traits have mostly been used that can be detected visually on an individual plant basis. However, in the background of such mutants other valuable mutations have been found in later generations. In cross-breeding with mutants valuable characteristics occurred, which could not be predicted from the phenotypes of the parents. It is concluded that improved attributes in the released mutant varieties do not comprise the entire genetic variation that could derive from mutagenesis. Current selection techniques are inadequate to exploit the full potential of mutagenesis for plant breeding. (author)

Rectus sheath abscess after laparoscopic appendicectomy

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Golash Vishwanath

2007-01-01

Full Text Available Port site wound infection, abdominal wall hematoma and intraabdominal abscess formation has been reported after laparoscopic appendicectomy. We describe here a rectus sheath abscess which occurred three weeks after the laparoscopic appendicectomy. It was most likely the result of secondary infection of the rectus sheath hematoma due to bleeding into the rectus sheath from damage to the inferior epigastric arteries or a direct tear of the rectus muscle. As far as we are aware this complication has not been reported after laparoscopic appendicectomy.

A sheath model for arbitrary radiofrequency waveforms

Science.gov (United States)

Turner, M. M.; Chabert, Pascal

2012-10-01

The sheath is often the most important region of a rf plasma, because discharge impedance, power absorption and ion acceleration are critically affected by the behaviour of the sheath. Consequently, models of the sheath are central to any understanding of the physics of rf plasmas. Lieberman has supplied an analytical model for a radio-frequency sheath driven by a single frequency, but in recent years interest has been increasing in radio-frequency discharges excited by increasingly complex wave forms. There has been limited success in generalizing the Lieberman model in this direction, because of mathematical complexities. So there is essentially no sheath model available to describe many modern experiments. In this paper we present a new analytical sheath model, based on a simpler mathematical framework than that of Lieberman. For the single frequency case, this model yields scaling laws that are identical in form to those of Lieberman, differing only by numerical coefficients close to one. However, the new model may be straightforwardly solved for arbitrary current waveforms, and may be used to derive scaling laws for such complex waveforms. In this paper, we will describe the model and present some illustrative examples.

The characteristics of RF modulated plasma boundary sheaths: An analysis of the standard sheath model

Science.gov (United States)

Naggary, Schabnam; Brinkmann, Ralf Peter

2015-09-01

The characteristics of radio frequency (RF) modulated plasma boundary sheaths are studied on the basis of the so-called ``standard sheath model.'' This model assumes that the applied radio frequency ωRF is larger than the plasma frequency of the ions but smaller than that of the electrons. It comprises a phase-averaged ion model - consisting of an equation of continuity (with ionization neglected) and an equation of motion (with collisional ion-neutral interaction taken into account) - a phase-resolved electron model - consisting of an equation of continuity and the assumption of Boltzmann equilibrium -, and Poisson's equation for the electrical field. Previous investigations have studied the standard sheath model under additional approximations, most notably the assumption of a step-like electron front. This contribution presents an investigation and parameter study of the standard sheath model which avoids any further assumptions. The resulting density profiles and overall charge-voltage characteristics are compared with those of the step-model based theories. The authors gratefully acknowledge Efe Kemaneci for helpful comments and fruitful discussions.

Sheath heating in low-pressure capacitive radio frequency discharges

International Nuclear Information System (INIS)

Wood, B.P.

1991-01-01

Capacitively coupled, parallel plate, r.f. discharges are commonly used for materials processing. The electrons in such a discharge gain and lose energy by reflection from the oscillating sheaths which form at the electrodes. Previous models of the electron heating by this mechanism have assumed that the sheath motion is slow compared to the electron thermal velocity, so that the electron energy change from each reflection is small. Here, the heating rate, density, and sheath width relations are derived analytically in the limit of very fast sheath motion. Numerical results are presented spanning the slow and fast limits. Results from particle-in-cell simulations show that in the large-energy-change regime, an electron beam is produced on each sheath expansion. At low pressure, this beam can traverse the plasma and interact with the sheath at the opposite electrode, producing a beam energy and density dependence on the length of the discharge. The beam produces a time and space varying warm tail on the electron energy distribution. Two revised heating models are derived, assuming power-law and two-temperature electron energy distributions, with temporal variation in electron temperature. These revised models yield new predictions for the variation of the power, density, and sheath thickness with applied r.f. voltage. These predictions are compared with simulation results and laboratory experiment. The electron sheath motion is investigated experimentally by observing the signal on a floating probe in the sheath region. This is compared to the signal product by a non-linear circuit model which accounts for the perturbation of the sheath potential by the probe and includes various forms of sheath motion. The experimental observations are consistent with the analytical predictions. Experimental observations of plasma-sheath resonance oscillations are presented which agree with analytical predictions

Cytogenetic investigations of a narrow leaf garden bean mutation induced by gamma rays

International Nuclear Information System (INIS)

Zagorcheva, L.; Poryazov, I.; Nikolova, V.

1988-01-01

Narrow leaf mutations were found in M 2 after 80 and 100 Gy gamma irradiation of cv. Zarya seeds. They did not differ from one another neither in degree of character expression nor in pollen fertility. In M 3 and M 4 the mutants did not always preserve their type. The chromosomal behaviour of five narrow leaf mutants was followed. Data from investigations of meiosis showed that in 14.3% to 54.2% of the pollen mother cells (PMC) homologous chromosomes paired producing 11 bivalents. In 8.3 to 53.3% of PMC in four of the investigated mutants multivalents were found, represented mainly by quadrivalents and trivalents, while in 4.2% to 42.9% the chromosomes did not pair and produced univalents in diakinesis and MI. In three of the mutants investigated part of PMC had 11 bivalents and a supplementary small chromosome probably arising as a result of the observed structural chromosome changes. In MI it was included in the equatorial plate, in AI and AII it divided and its chromatides moved toward the poles of the division spindle to be included in daughter nuclei. 2 figs.; 1 tab.; 11 refs

Rectus sheath hematoma: three case reports

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Kapan Selin

2008-01-01

Full Text Available Abstract Introduction Rectus sheath hematoma is an uncommon cause of acute abdominal pain. It is an accumulation of blood in the sheath of the rectus abdominis, secondary to rupture of an epigastric vessel or muscle tear. It could occur spontaneously or after trauma. They are usually located infraumblically and often misdiagnosed as acute abdomen, inflammatory diseases or tumours of the abdomen. Case presentation We reported three cases of rectus sheath hematoma presenting with a mass in the abdomen and diagnosed by computerized tomography. The patients recovered uneventfully after bed rest, intravenous fluid replacement, blood transfusion and analgesic treatment. Conclusion Rectus sheath hematoma is a rarely seen pathology often misdiagnosed as acute abdomen that may lead to unnecessary laparotomies. Computerized tomography must be chosen for definitive diagnosis since ultrasonography is subject to error due to misinterpretation of the images. Main therapy is conservative management.

Sheath structure transition controlled by secondary electron emission

Science.gov (United States)

Schweigert, I. V.; Langendorf, S. J.; Walker, M. L. R.; Keidar, M.

2015-04-01

In particle-in-cell Monte Carlo collision (PIC MCC) simulations and in an experiment we study sheath formation over an emissive floating Al2O3 plate in a direct current discharge plasma at argon gas pressure 10-4 Torr. The discharge glow is maintained by the beam electrons emitted from a negatively biased hot cathode. We observe three types of sheaths near the floating emissive plate and the transition between them is driven by changing the negative bias. The Debye sheath appears at lower voltages, when secondary electron emission is negligible. With increasing applied voltage, secondary electron emission switches on and a first transition to a new sheath type, beam electron emission (BEE), takes place. For the first time we find this specific regime of sheath operation near the floating emissive surface. In this regime, the potential drop over the plate sheath is about four times larger than the temperature of plasma electrons. The virtual cathode appears near the emissive plate and its modification helps to maintain the BEE regime within some voltage range. Further increase of the applied voltage U initiates the second smooth transition to the plasma electron emission sheath regime and the ratio Δφs/Te tends to unity with increasing U. The oscillatory behavior of the emissive sheath is analyzed in PIC MCC simulations. A plasmoid of slow electrons is formed near the plate and transported to the bulk plasma periodically with a frequency of about 25 kHz.

Composition of the sheath produced by the green alga Chlorella sorokiniana.

Science.gov (United States)

Watanabe, K; Imase, M; Sasaki, K; Ohmura, N; Saiki, H; Tanaka, H

2006-05-01

To investigate the chemical characterization of the mucilage sheath produced by Chlorella sorokiniana. Algal mucilage sheath was hydrolysed with NaOH, containing EDTA. The purity of the hydrolysed sheath was determined by an ATP assay. The composition of polysaccharide in the sheath was investigated by high-performance anion-exchange chromatography with pulsed amperometric detection. Sucrose, galacturonic acid, xylitol, inositol, ribose, mannose, arabinose, galactose, rhamnose and fructose were detected in the sheath as sugar components. Magnesium was detected in the sheath as a divalent cation using inductively coupled argon plasma. The sheath matrix also contained protein. It appears that the sheath is composed of sugars and metals. Mucilage sheath contains many kinds of saccharides that are produced as photosynthetic metabolites and divalent cations that are contained in the culture medium. This is the first report on chemical characterization of the sheath matrix produced by C. sorokiniana.

Studies of irradiated zircaloy fuel sheathing using XPS

Energy Technology Data Exchange (ETDEWEB)

Chan, P K; Irving, K G [Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Hocking, W H; Duclos, A M; Gerwing, A F [Atomic Energy of Canada Ltd., Pinawa, MB (Canada). Whiteshell Labs.

1996-12-31

The preliminary results reported here support the hypothesis that CANLUB graphite coating reduces the rate at which oxygen can react with fuel sheathing. X-ray photoelectron spectroscopic (XPS) characterization of Zircaloy sheathing obtained from extended-burnup Bruce-type elements (BDL-406-XY (555 MW.h/kgU) and BDL-406-AAH (731 MW.h/kgU)) irradiated in NRU indicates that CANLUB may reduce fuel sheath oxidation, and hence that fission-liberated oxygen may remain in the fuel. Chemical shifts in the Zr 3d spectra suggest that a stoichiometric (ZrO{sub 2}) oxide film was formed only on Zircaloy in direct contact with fuel. Particulate fuel adhering to the sheath was also determined to be systematically more oxidized on surfaces with CANLUB than on those without it. The unique association of tin on sheathing specimens with the non-CANLUB-coated specimens might also suggest that the tin had segregated from the sheathing. It must be emphasized that further experiments are required to better define the effect of CANLUB on fuel oxidation. (author). 14 refs., 1 tab., 3 figs.

Studies of irradiated zircaloy fuel sheathing using XPS

International Nuclear Information System (INIS)

Chan, P.K.; Irving, K.G.; Hocking, W.H.; Duclos, A.M.; Gerwing, A.F.

1995-01-01

The preliminary results reported here support the hypothesis that CANLUB graphite coating reduces the rate at which oxygen can react with fuel sheathing. X-ray photoelectron spectroscopic (XPS) characterization of Zircaloy sheathing obtained from extended-burnup Bruce-type elements (BDL-406-XY (555 MW.h/kgU) and BDL-406-AAH (731 MW.h/kgU)) irradiated in NRU indicates that CANLUB may reduce fuel sheath oxidation, and hence that fission-liberated oxygen may remain in the fuel. Chemical shifts in the Zr 3d spectra suggest that a stoichiometric (ZrO 2 ) oxide film was formed only on Zircaloy in direct contact with fuel. Particulate fuel adhering to the sheath was also determined to be systematically more oxidized on surfaces with CANLUB than on those without it. The unique association of tin on sheathing specimens with the non-CANLUB-coated specimens might also suggest that the tin had segregated from the sheathing. It must be emphasized that further experiments are required to better define the effect of CANLUB on fuel oxidation. (author). 14 refs., 1 tab., 3 figs

Dynamic sheath studies in plasma source ion implantation

International Nuclear Information System (INIS)

Schever, J.T.; Shamim, M.; Conrad, J.R.

1990-01-01

Plasma Source Ion Implantation (PSII) is a non-line-of-sight method for materials processing in which a target is immersed in a plasma and pulse biased to a high negative voltage (∼ 50 kV). A model of the dynamic sheath which forms under these conditions has been developed and applied to planar, cylindrical and spherical geometries. This model assumes that the transient sheath obeys the Child-Langmuir law for space charge limited emission at each instant during the propagation. Ions uncovered by the propagating sheath edge supply the space charge limited current. This yields an equation relating sheath edge velocity to position, which can be integrated to obtain the sheath edge position as a function of time. The same procedure used in cylindrical and spherical geometry results in a similar equation which must be integrated numerically. Comparison of results of experimental measurements, our model and simulation will be presented for the dynamic sheath edge position and target current waveform. Measurements of implanted dose uniformity of wedge shaped targets are also presented

Analytical expression for sheath edge around corner cathodes

International Nuclear Information System (INIS)

Sheridan, T E

2009-01-01

A simple analytical expression for the position of the sheath edge around a two-dimensional corner cathode with included angle θ c has been discovered. This expression is valid for weakly collisional sheaths in the Child-Langmuir regime φ c >> kT e /e, where -φ c e is the electron temperature. In polar coordinates (r, θ), the sheath edge is given by (r/s 0 )sin[πθ/(2π - θ c )] = [π/(2π - θ c )] where s 0 is the planar sheath width far from the vertex of the corner. This result is verified by comparison with previous numerical solutions (Watterson P A 1989 J. Phys. D: Appl. Phys. 22 1300) for the knife edge (θ c = 0) and convex square corner (θ c = π/2). The observed agreement suggests that this expression gives the sheath edge for all corner angles, both concave and convex. The utility of this result is demonstrated by computing the full sheath solution for a knife-edge cathode with φ c = 100kT e /e.

Genetic Analysis of Streaked and Abnormal Floret Mutant st-fon

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De-xi CHEN

2013-07-01

Full Text Available A double mutant with streaked leaf and abnormal floret was found and temporarily named streaked leaf and floral organ number mutant (st-fon. For this mutant, besides white streak appeared on culm, leaves and panicles, the number of floral organs increased and florets cracked. The extreme phenotype was that several small florets grew from one floret or branch rachis in small florets extended and developed into panicles. By using transmission electron microscope to observe the ultrastructure of white histocytes of leaves at the seedling stage, the white tissues which showed abnormal plastids, lamellas and thylakoids could not develop into normal chloroplast, and the development of chloroplast was blocked at the early growth stage of plastid. Scanning electron microscope and paraffin section were also used to observe the development of floral organs, and the results indicated that the development of floral meristem was out of order and unlimited, whereas in the twisty leaves, vascular bundle sheath cells grew excessively, or some bubbly cells increased. Genetic analyses carried out by means of cross and backcross with four normal-leaf-color materials revealed that the mutant is of cytoplasm inheritance.

Non-Maxwellian plasma sheaths

International Nuclear Information System (INIS)

Haines, M.G.

1998-01-01

There is much experimental evidence that heat flux to divertor plates or to limiters is very asymmetric. For example, Lowry made measurements on poloidal limiters in JET, Stangeby and McCracken reported asymmetries in several experiments. In 1991 Haines considered the effects on the Child-Langmuir sheaths of having a net current flow. It was found that a sheath that receives more ions than electrons receives more energy flux than a sheath that receives more electrons than ions. We now extend the model to include for the electrons departures from a Maxwellian distribution arising from a net current flow, heat flow and thermoelectric effects in the scrape-off layer (SOL). It is envisaged that a net current flows in the SOL due to applied or induced electric fields, and is of a magnitude similar to that in the adjacent bulk plasma, though reduced due to the lower temperature in the SOL. We employ conventional linear transport theory eg. Braginskii, Epperlein and Haines in which the ions are a stationary Maxwellian. (orig.)

How to Patch Active Plasma and Collisionless Sheath: Practical Guide

International Nuclear Information System (INIS)

Kaganovich, Igor D.

2002-01-01

Most plasmas have a very thin sheath compared with the plasma dimension. This necessitates separate calculations of the plasma and sheath. The Bohm criterion provides the boundary condition for calculation of plasma profiles. To calculate sheath properties, a value of electric field at the plasma-sheath interface has to be specified in addition to the Bohm criterion. The value of the boundary electric field and robust procedure to approximately patch plasma and collisionless sheath with a very good accuracy are reported

Plasma sheath in non-Maxwellian plasma

International Nuclear Information System (INIS)

Shimizu, Takuo; Horigome, Takashi

1992-01-01

Reviewing many theoretical and experimental works on the electron-energy distributions (EEDF) of various plasmas, we point out that many plasmas have EEDF of non-Maxwellian in shape. Therefore, the recent treatment of plasma sheath using the Maxwell-Boltzmann distribution approximation should be improved. To do this, we have adopted Rutcher's standard distribution as a generalized form in place of the traditional Maxwellian, and found that the minimum energy of ions entering the sheath edge (Bohm's criterion) varies largely, and have also shown the variation of Debye length with the shape of EEDF. The length is the most important parameter to proceed with more detailed analysis on plasma-sheaths, and also to control them in the future. (author)

Theory of the Electron Sheath and Presheath

Science.gov (United States)

Scheiner, Brett; Baalrud, Scott; Yee, Benjamin; Hopkins, Matthew; Barnat, Edward

2015-09-01

Electron sheaths are commonly found near Langmuir probes collecting the electron saturation current. The common assumption is that the probe collects the random flux of electrons incident on the sheath, which tacitly implies that there is no electron presheath and that the flux collected is due to a velocity space truncation of the velocity distribution function (VDF). This work provides a dedicated theory of electron sheaths, which suggests that electron sheaths are not so simple. Motivated by VDFs observed in recent Particle-In-Cell (PIC) simulations, we develop a 1D model for the electron sheath and presheath. In the model, under low temperature plasma conditions, an electron pressure gradient accelerates electrons in the presheath to a flow velocity that exceeds the electron thermal speed at the sheath edge. This pressure gradient allows the generation of large flows compared to those that would be generated by the electric field alone. It is due to this pressure gradient that the electron presheath extends much further into the plasma (nominally by a factor of √{mi /me }) than an analogous ion presheath. Results of the model are compared with PIC simulations. This work was supported by the Office of Fusion Energy Science at the U.S. Department of Energy under contract DE-AC04-94SL85000 and by the Office of Science Graduate Student Research (SCGSR) program under Contract Number DE-AC05-06OR23100.

Anode sheath in Hall thrusters

International Nuclear Information System (INIS)

Dorf, L.; Semenov, V.; Raitses, Y.

2003-01-01

A set of hydrodynamic equations is used to describe quasineutral plasma in ionization and acceleration regions of a Hall thruster. The electron distribution function and Poisson equation are invoked for description of a near-anode region. Numerical solutions suggest that steady-state operation of a Hall thruster can be achieved at different anode sheath regimes. It is shown that the anode sheath depends on the thruster operating conditions, namely the discharge voltage and the mass flow rate

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Science.gov (United States)

Kunoh, Tatsuki; Hashimoto, Hideki; McFarlane, Ian R.; Hayashi, Naoaki; Suzuki, Tomoko; Taketa, Eisuke; Tamura, Katsunori; Takano, Mikio; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

2016-01-01

Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II) to Fe(III) and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II) concentrations, Fe(III) precipitates visibly formed immediately after addition of Fe(II) to the medium, suggesting prompt abiotic oxidation of Fe(II) to Fe(III). Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III) was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II) medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter), while those in the Fe(III) medium were composed of large, aggregated particles (≥3 µm diameter) with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved) of Fe encrustation of the Leptothrix sheaths. PMID:27271677

Abiotic Deposition of Fe Complexes onto Leptothrix Sheaths

Directory of Open Access Journals (Sweden)

Tatsuki Kunoh

2016-06-01

Full Text Available Bacteria classified in species of the genus Leptothrix produce extracellular, microtubular, Fe-encrusted sheaths. The encrustation has been previously linked to bacterial Fe oxidases, which oxidize Fe(II to Fe(III and/or active groups of bacterial exopolymers within sheaths to attract and bind aqueous-phase inorganics. When L. cholodnii SP-6 cells were cultured in media amended with high Fe(II concentrations, Fe(III precipitates visibly formed immediately after addition of Fe(II to the medium, suggesting prompt abiotic oxidation of Fe(II to Fe(III. Intriguingly, these precipitates were deposited onto the sheath surface of bacterial cells as the population was actively growing. When Fe(III was added to the medium, similar precipitates formed in the medium first and were abiotically deposited onto the sheath surfaces. The precipitates in the Fe(II medium were composed of assemblies of globular, amorphous particles (ca. 50 nm diameter, while those in the Fe(III medium were composed of large, aggregated particles (≥3 µm diameter with a similar amorphous structure. These precipitates also adhered to cell-free sheaths. We thus concluded that direct abiotic deposition of Fe complexes onto the sheath surface occurs independently of cellular activity in liquid media containing Fe salts, although it remains unclear how this deposition is associated with the previously proposed mechanisms (oxidation enzyme- and/or active group of organic components-involved of Fe encrustation of the Leptothrix sheaths.

Novel root-fungus symbiosis in Ericaceae: sheathed ericoid mycorrhiza formed by a hitherto undescribed basidiomycete with affinities to Trechisporales.

Directory of Open Access Journals (Sweden)

Martin Vohník

Full Text Available Ericaceae (the heath family are widely distributed calcifuges inhabiting soils with inherently poor nutrient status. Ericaceae overcome nutrient limitation through symbiosis with ericoid mycorrhizal (ErM fungi that mobilize nutrients complexed in recalcitrant organic matter. At present, recognized ErM fungi include a narrow taxonomic range within the Ascomycota, and the Sebacinales, basal Hymenomycetes with unclamped hyphae and imperforate parenthesomes. Here we describe a novel type of basidiomycetous ErM symbiosis, termed 'sheathed ericoid mycorrhiza', discovered in two habitats in mid-Norway as a co-dominant mycorrhizal symbiosis in Vaccinium spp. The basidiomycete forming sheathed ErM possesses clamped hyphae with perforate parenthesomes, produces 1- to 3-layer sheaths around terminal parts of hair roots and colonizes their rhizodermis intracellularly forming hyphal coils typical for ErM symbiosis. Two basidiomycetous isolates were obtained from sheathed ErM and molecular and phylogenetic tools were used to determine their identity; they were also examined for the ability to form sheathed ErM and lignocellulolytic potential. Surprisingly, ITS rDNA of both conspecific isolates failed to amplify with the most commonly used primer pairs, including ITS1 and ITS1F + ITS4. Phylogenetic analysis of nuclear LSU, SSU and 5.8S rDNA indicates that the basidiomycete occupies a long branch residing in the proximity of Trechisporales and Hymenochaetales, but lacks a clear sequence relationship (>90% similarity to fungi currently placed in these orders. The basidiomycete formed the characteristic sheathed ErM symbiosis and enhanced growth of Vaccinium spp. in vitro, and degraded a recalcitrant aromatic substrate that was left unaltered by common ErM ascomycetes. Our findings provide coherent evidence that this hitherto undescribed basidiomycete forms a morphologically distinct ErM symbiosis that may occur at significant levels under natural conditions, yet

Farris-Tang retractor in optic nerve sheath decompression surgery.

Science.gov (United States)

Spiegel, Jennifer A; Sokol, Jason A; Whittaker, Thomas J; Bernard, Benjamin; Farris, Bradley K

2016-01-01

Our purpose is to introduce the use of the Farris-Tang retractor in optic nerve sheath decompression surgery. The procedure of optic nerve sheath fenestration was reviewed at our tertiary care teaching hospital, including the use of the Farris-Tang retractor. Pseudotumor cerebri is a syndrome of increased intracranial pressure without a clear cause. Surgical treatment can be effective in cases in which medical therapy has failed and disc swelling with visual field loss progresses. Optic nerve sheath decompression surgery (ONDS) involves cutting slits or windows in the optic nerve sheath to allow cerebrospinal fluid to escape, reducing the pressure around the optic nerve. We introduce the Farris-Tang retractor, a retractor that allows for excellent visualization of the optic nerve sheath during this surgery, facilitating the fenestration of the sheath and visualization of the subsequent cerebrospinal fluid egress. Utilizing a medial conjunctival approach, the Farris-Tang retractor allows for easy retraction of the medial orbital tissue and reduces the incidence of orbital fat protrusion through Tenon's capsule. The Farris-Tang retractor allows safe, easy, and effective access to the optic nerve with good visualization in optic nerve sheath decompression surgery. This, in turn, allows for greater surgical efficiency and positive patient outcomes.

Evidence for a Role for NAD(P)H Dehydrogenase in Concentration of CO2 in the Bundle Sheath Cell of Zea mays.

Science.gov (United States)

Peterson, Richard B; Schultes, Neil P; McHale, Neil A; Zelitch, Israel

2016-05-01

Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2 This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199-224]. © 2016 American Society of Plant Biologists. All Rights Reserved.

Effect of collisions on photoelectron sheath in a gas

Science.gov (United States)

Sodha, Mahendra Singh; Mishra, S. K.

2016-02-01

This paper presents a study of the effect of the collision of electrons with atoms/molecules on the structure of a photoelectron sheath. Considering the half Fermi-Dirac distribution of photo-emitted electrons, an expression for the electron density in the sheath has been derived in terms of the electric potential and the structure of the sheath has been investigated by incorporating Poisson's equation in the analysis. The method of successive approximations has been used to solve Poisson's equation with the solution for the electric potential in the case of vacuum, obtained earlier [Sodha and Mishra, Phys. Plasmas 21, 093704 (2014)], being used as the zeroth order solution for the present analysis. The inclusion of collisions influences the photoelectron sheath structure significantly; a reduction in the sheath width with increasing collisions is obtained.

Effect of two-temperature electrons distribution on an electrostatic plasma sheath

International Nuclear Information System (INIS)

Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

2013-01-01

A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

A suitable boundary condition for bounded plasma simulation without sheath resolution

International Nuclear Information System (INIS)

Parker, S.E.; Procassini, R.J.; Birdsall, C.K.; Cohen, B.I.

1993-01-01

We have developed a technique that allows for a sheath boundary layer without having to resolve the inherently small space and time scales of the sheath region. We refer to this technique as the logical sheath boundary condition. This boundary condition, when incorporated into a direct-implicit particle code, permits large space- and time-scale simulations of bounded systems, which would otherwise be impractical on current supercomputers. The lack of resolution of the collector sheath potential drop obtained from conventional implicit simulations at moderate values of ω pe Δt and Δz/λ De provides the motivation for the development of the logical sheath boundary condition. The algorithm for use of the logical sheath boundary condition in a particle simulation is presented. Results from simulations which use the logical sheath boundary condition are shown to compare reasonably well with those from an analytic theory and simulations in which the sheath is resolved

Electrospinning jet behaviors under the constraints of a sheath gas

Directory of Open Access Journals (Sweden)

Yang Zhao

2016-11-01

Full Text Available Increasing the ejection efficiency and uniformity of nanofibers is the key to applications of electrospinning technology. In this work, a novel electrospinning spinneret with a sheath gas passageway is designed. The frictional resistance that stems from the sheath gas provides additional stretching and restriction forces on the jet. The sheath gas also reduces interference and enhances the stability of the charged jet. A bead-on-strain simulation model is built up to determine the constraint effects of the sheath gas. Simulation results show that the sheath gas decreases the motion area and increases the stretching ratio of the liquid jet. The stretching force from the sheath gas decreases the diameter and increases the uniformity of the nanofiber. As the gas pressure increases from 0 kPa to 50 kPa, the critical voltage of the jet ejection decreases from 8.4 kV to 2.5 kV, the diameter of the nanofiber deposition zone decreases from 40 cm to 10 cm, and the diameter of the nanofibers decreases from 557.97 nm to 277.73 nm. The uniformity of nanofibers can be improved significantly using a sheath gas. The sheath gas contributes to the rapid deposition of a uniform nanofibrous membrane and the industrial applications of electrospinning.

Use of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement

International Nuclear Information System (INIS)

Bae, Jae-Ik; Shin, Ji Hoon; Song, Ho-Young; Yoon, Chang Jin; Nam, Deok Ho; Choi, Won-Chan; Lim, Jin-Oh

2005-01-01

Our purpose was to assess the safety and usefulness of guiding sheaths in peroral fluoroscopic gastroduodenal stent placement. Two types of guiding sheath were made from straight polytetrafluoroethylene tubes. Type A was 80 cm in length, 4 mm in outer diameter and 3 mm in inner diameter. Type B was 70 cm in length, 6 mm in outer diameter and 5 mm in inner diameter. The type A sheath was used in 18 patients in whom a catheter-guide wire combination failed to pass through a stricture. The type B sheath was used in 22 patients in whom a stent delivery system failed to pass through the stricture due to loop formation within the gastric lumen. The overall success rate for guiding a catheter-guide wire through a stricture after using the type A sheath was 89%. The overall success rate for passing a stent delivery system through a stricture after using the type B sheath was 100%. All procedures were tolerated by the patients without any significant complications. The guiding sheaths were safe and useful in peroral fluoroscopic gastroduodenal stent placement. (orig.)

Experimental investigation of plasma sheaths in magnetic mirror and cusp configurations

Science.gov (United States)

Jiang, Zhengqi; Wei, Zi-an; Ma, J. X.

2017-11-01

Sheath structures near a metal plate in a magnetized plasma were experimentally investigated in magnetic mirror and cusp configurations. Plasma parameters and the sheath potential distributions were probed by a planar and an emissive probe, respectively. The measured sheath profiles in the mirror configuration show that the sheath thickness first decreases and then increases when the magnetic strength is raised. A magnetic flux-tube model was used to explain this result. In the cusp configuration, the measured sheath thickness decreases with the increase of the coil current creating the magnetic cusp. However, when normalized by the electron Debye length, the dependence of the sheath thickness on the coil current is reversed.

Behavior of collisional sheath in electronegative plasma with q-nonextensive electron distribution

Science.gov (United States)

Borgohain, Dima Rani; Saharia, K.

2018-03-01

Electronegative plasma sheath is addressed in a collisional unmagnetized plasma consisting of q-nonextensive electrons, Boltzmann distributed negative ions and cold fluid positive ions. Considering the positive ion-neutral collisions and ignoring the effects of ionization and collisions between negative species and positive ions (neutrals), a modified Bohm sheath criterion and hence floating potential are derived by using multifluid model. Using the modified Bohm sheath criterion, the sheath characteristics such as spatial profiles of density, potential and net space charge density have been numerically investigated. It is found that increasing values of q-nonextensivity, electronegativity and collisionality lead to a decrease of the sheath thickness and an increase of the sheath potential and the net space charge density. With increasing values of the electron temperature to negative ion temperature ratio, the sheath thickness increases and the sheath potential as well as the net space charge density in the sheath region decreases.

ALINE: A device dedicated to understanding radio-frequency sheaths

Directory of Open Access Journals (Sweden)

S. Devaux

2017-08-01

Full Text Available In fusion devices, radiofrequency (RF antennas are used for heating the plasma. Those antennas and the plasma interact with each other through the so-called RF sheaths, layers of plasma where the quasi-neutrality breaks down and large electric fields arise. Among the effects of RF sheaths, there is the enhancement of the particles and energy fluxes toward the surface of the antenna, which in turn generate hot spots and release impurities, which are both deleterious for plasma operations. RF sheaths comprehension stumbles on the difficulty to achieve in situ measurements of the sheath properties, as scrape-off layer plasmas are a harsh environment. The very goal of the ALINE device is to tackle this issue and to fulfil the blank between numerical simulations and full-scale experiment by providing measurements within the RF sheaths in a controlled environment. In this paper we report on the latest experimental results from ALINE, in which a cylindrical Langmuir probe mounted on a remotely controlled and programmable arm allows for plasma characterizations in the three dimensions of space around the stainless steel antenna, including the sheath. We present a series of density and potential profiles and three dimension (3D maps in the plasma surrounding a stainless-steel RF antenna as well as in the sheath itself, for unmagnetized and magnetized plasmas.

In vivo engineering of a functional tendon sheath in a hen model.

Science.gov (United States)

Xu, Liang; Cao, Dejun; Liu, Wei; Zhou, Guangdong; Zhang, Wen Jie; Cao, Yilin

2010-05-01

Repair of injured tendon sheath remains a major challenge and this study explored the possibility of in vivo reconstruction of a tendon sheath with tendon sheath derived cells and polyglycolic acid (PGA) fibers in a Leghorn hen model. Total 55 Leghorn hens with a 1cm tendon sheath defect created in the left middle toe of each animal were randomly assigned into: (1) experimental group (n=19) that received a cell-PGA construct; (2) scaffold control group (n=18) that received a cell-free PGA scaffold; (3) blank control group (n=18) with the defect untreated. Tendon sheath cells were isolated, in vitro expanded, and seeded onto PGA scaffolds. After in vitro culture for 7 days, the constructs were in vivo implanted to repair the sheath defects. Alcian blue staining confirmed the ability of cultured cells to produce specific matrices containing acidic carboxyl mucopolysaccharide (mainly hyaluronic acid). In addition, the engineered sheath formed a relatively mature structure at 12 weeks post-surgery, which was similar to that of native counterpart, including a smooth inner surface, a well-developed sheath histological structure with a clear space between the tendon and the engineered sheath. More importantly, Work of Flexion assay revealed that the tendons needed less power consumption to glide inside the engineered sheath when compared to the tendons which were surrounded by scar-repaired tissues, indicating that the engineered sheaths had gained the function to a certain extent of preventing tendon adhesion. Taken together, these results suggest that tendon sheaths that are functionally and structurally similar to native sheaths are possible to be engineered in vivo using tendon sheath cells and PGA scaffolds. Copyright 2010 Elsevier Ltd. All rights reserved.

Intrapontine malignant nerve sheath tumor

DEFF Research Database (Denmark)

Kozić, Dusko; Nagulić, Mirjana; Samardzić, Miroslav

2008-01-01

. On pathological examination, the neoplasm appeared to be an intrapontine nerve sheath tumor originating most likely from the intrapontine segment of one of the cranial nerve fibres. The tumor showed exophytic growth, with consequent spread to adjacent subaracnoid space. MR spectroscopy revealed the presence......The primary source of malignant intracerebral nerve sheath tumors is still unclear We report the imaging and MR spectroscopic findings in a 39-year-old man with a very rare brain stem tumor MR examination revealed the presence of intraaxial brain stem tumor with a partial exophytic growth...

The Child-Langmuir law and analytical theory of collisionless to collision-dominated sheaths

International Nuclear Information System (INIS)

Benilov, M S

2009-01-01

This paper is concerned with summarizing simple analytical models of space-charge sheaths and tracing their relation to the Child-Langmuir model of an ion sheath. The topics discussed include the Child-Langmuir law and model of a collisionless ion sheath, the Mott-Gurney law and model of a collision-dominated ion sheath, the Bohm model of a collisionless ion-electron sheath, the Su-Lam-Cohen model of a collision-dominated ion-electron sheath, ion sheaths with arbitrary collisionality, high-accuracy boundary conditions for the Child-Langmuir and Mott-Gurney models of an ion sheath and the mathematical sense of Child-Langmuir type models of an ion sheath from the point of view of modern theoretical physics.

What is the size of a floating sheath? An answer

Science.gov (United States)

Voigt, Farina; Naggary, Schabnam; Brinkmann, Ralf Peter

2016-09-01

The formation of a non-neutral boundary sheath in front of material surfaces is universal plasma phenomenon. Despite several decades of research, however, not all related issues are fully clarified. In a recent paper, Chabert pointed out that this lack of clarity applies even to the seemingly innocuous question ``What the size of a floating sheath?'' This contribution attempts to provide an answer that is not arbitrary: The size of a floating sheath is defined as the plate separation of an equivalent parallel plate capacitor. The consequences of the definition are explored with the help of a self-consistent sheath model, and a comparison is made with other sheath size definitions. Deutsche Forschungsgemeinschaft within SFB TR 87.

Effects of emitted electron temperature on the plasma sheath

International Nuclear Information System (INIS)

Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.

2014-01-01

It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03T e /e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux

Sheath impedance effects in very high frequency plasma experiments

International Nuclear Information System (INIS)

Schwarzenbach, W.; Howling, A.A.; Fivaz, M.; Brunner, S.; Hollenstein, C.

1995-05-01

The frequency dependence (13.56 MHz to 70 MHz) of the ion energy distribution at the ground electrode was measured by mass spectrometry in a symmetrical capacitive argon discharge. Reduced sheath impedance at Very High Frequency allows high levels of plasma power and substrate ion flux whilst maintaining low levels of ion energy and electrode voltage. The lower limit of ion bombardment energy is fixed by the sheath floating potential at high frequency, in contrast to low frequencies where only the rf voltage amplitude is determinant. The capacitive sheaths are thinner at high frequencies which accentuates the high frequency reduction in sheath impedance. It is argued that the frequency dependence of sheath impedance is responsible for the principal characteristics of Very High Frequency plasmas. The measurements are summarised by simple physical descriptions and compared with a Particle-In-Cell simulation. (author) figs., tabs., refs

Genomic and Expression Profiling of Benign and Malignant Nerve Sheath Profiling of Benign and Malignant Nerve Sheath

Science.gov (United States)

2007-05-01

Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis Patients PRINCIPAL INVESTIGATOR: Matt van de Rijn, M.D., Ph.D. Torsten...Annual 3. DATES COVERED 1 May 2006 –30 Apr 2007 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Genomic and Expression Profiling of Benign and Malignant Nerve...Award Number: DAMD17-03-1-0297 Title: Genomic and Expression Profiling of Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis

Nondestructive testing of metallic sheath for internally cooled superconductor

International Nuclear Information System (INIS)

McClung, R.W.; Cook, K.V.; Dodd, C.V.; Smith, J.H.

1983-01-01

For quality assurance in the Oak Ridge National Laboratory Large Coil Program, we developed ultrasonic and eddy-current techniques to examine the JBK-75 alloy sheath for superconducting cable for a large magnet. Ultrasound was used to examine the strip before forming into the sheath, and eddy currents were used to examine the seam weld after the sheath had been formed around the cable

Plasma Sheath Behavior in a Coaxial Discharge Device

International Nuclear Information System (INIS)

EL-Aragi, G.; Soliman, H.M.; Masoud, M.M.

2001-01-01

The behavior of the plasma sheath has been studied experimentally and theoretically for 3 kJ coaxial discharge device. The discharge takes place in argon gas with pressure of 0.8 mbar. The experiments are conducted with a 10 kV bank charging voltage, which corresponds to 110 kA peak discharge current with time period of 34 μs. The experimental investigations have been studied using a magnetic probes and a miniature Rogowsky coil. A snowplough model is used to drive an analytical solution of the plasma sheath behavior in axial direction. Measurements of radial distribution of plasma sheath current density J r at the muzzle, show that J r has the following relation, J r is proportional to r -1.1 . From the experimental results and theoretical calculations of axial distribution of azimuthal magnetic field induction and plasma sheath velocity, the inclination angle between the normal of the plasma sheath with the axial distance at any axial position is evaluated and it has approximately a constant value for most axial distances. Also, the axial motion of plasma sheath acceleration is estimated experimentally a max = 0.13 x 10 12 ' cm / s 2 at z = 11 cm and from theoretical calculations a max = 0.15 x 10 12 cm/ s 2 at max z = 1.6 cm. A comparison of the experimental results with the theoretical calculations, under the assumption of the snowplough model are not in agreement. (author)

Stability of the Tonks–Langmuir discharge pre-sheath

Energy Technology Data Exchange (ETDEWEB)

Tskhakaya, D. D. [Fusion@ÖAW, Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna (Austria); Kos, L. [LECAD Laboratory, Faculty of Mechanical Engineering, University of Ljubljana, SI-1000 Ljubljana (Slovenia); Tskhakaya, D. [Fusion@ÖAW, Institute of Applied Physics, TU Wien, Wiedner Hauptstraße 8-10, 1040 Vienna (Austria); Institute for Theoretical Physics, University of Innsbruck, A-6020 Innsbruck (Austria)

2016-03-15

The article formulates the stability problem of the plasma sheath in the Tonks–Langmuir discharge. Using the kinetic description of the ion gas, i.e., the stability of the potential shape in the quasi-neutral pre-sheath regarding the high and low frequency, the perturbations are investigated. The electrons are assumed to be Maxwell–Boltzmann distributed. Regarding high-frequency perturbations, the pre-sheath is shown to be stable. The stability problem regarding low-frequency perturbations can be reduced to an analysis of the “diffusion like” equation, which results in the instability of the potential distribution in the pre-sheath. By means of the Particle in Cell simulations, also the nonlinear stage of low frequency oscillations is investigated. Comparing the figure obtained with the figure for linear stage, one can find obvious similarity in the spatial-temporal behavior of the potential.

The magnetized sheath of a dusty plasma with grains size distribution

International Nuclear Information System (INIS)

Ou, Jing; Gan, Chunyun; Lin, Binbin; Yang, Jinhong

2015-01-01

The structure of a plasma sheath in the presence of dust grains size distribution (DGSD) is investigated in the multi-fluid framework. It is shown that effect of the dust grains with different sizes on the sheath structure is a collective behavior. The spatial distributions of electric potential, the electron and ion densities and velocities, and the dust grains surface potential are strongly affected by DGSD. The dynamics of dust grains with different sizes in the sheath depend on not only DGSD but also their radius. By comparison of the sheath structure, it is found that under the same expected value of DGSD condition, the sheath length is longer in the case of lognormal distribution than that in the case of uniform distribution. In two cases of normal and lognormal distributions, the sheath length is almost equal for the small variance of DGSD, and then the difference of sheath length increases gradually with increase in the variance

An analytical investigation: Effect of solar wind on lunar photoelectron sheath

Science.gov (United States)

Mishra, S. K.; Misra, Shikha

2018-02-01

The formation of a photoelectron sheath over the lunar surface and subsequent dust levitation, under the influence of solar wind plasma and continuous solar radiation, has been analytically investigated. The photoelectron sheath characteristics have been evaluated using the Poisson equation configured with population density contributions from half Fermi-Dirac distribution of the photoemitted electrons and simplified Maxwellian statistics of solar wind plasma; as a consequence, altitude profiles for electric potential, electric field, and population density within the photoelectron sheath have been derived. The expression for the accretion rate of sheath electrons over the levitated spherical particles using anisotropic photoelectron flux has been derived, which has been further utilized to characterize the charging of levitating fine particles in the lunar sheath along with other constituent photoemission and solar wind fluxes. This estimate of particle charge has been further manifested with lunar sheath characteristics to evaluate the altitude profile of the particle size exhibiting levitation. The inclusion of solar wind flux into analysis is noticed to reduce the sheath span and altitude of the particle levitation; the dependence of the sheath structure and particle levitation on the solar wind plasma parameters has been discussed and graphically presented.

Short communication. A spontaneous mutant of L-202 rice

Energy Technology Data Exchange (ETDEWEB)

Garcia-Yzaguire, A.; Padrones, T.

2009-07-01

A new spontaneous phenotype of the rice cultivar L-202 was found. Mendelian analysis indicates that it is a monogenic, recessive mutant. Its distinguishing features are: dark blue-green colour, short and narrow leaves, high tillering and relatively short height. The objectives of this study were: to characterize it, to determine if it is heritable and if so, its genetic basis. Its distinguishing features are: dark blue-green colour, short and narrow leaves, high tillering and relatively short height. Selfing the new phenotype resulted in a uniform progeny, with the traits of the parent plant (wild type). Crossing the new phenotype with the normal L-202 cultivar resulted in a uniform F1 hybrid generation, with the wild type. The F2 generation showed a mendelian segregation which did not depart significantly from three normal plants : one new phenotype. It is concluded that it is a monogenic, recessive mutant. (Author) 3 refs.

Simulations of rf-driven sheath formation in two dimensions

International Nuclear Information System (INIS)

Riyopoulos, S.; Grossmann, W.; Drobot, A.; Kress, M.

1992-01-01

The results from two-dimensional particle simulations of sheath formation around periodic metal arrays placed inside magnetized plasmas and driven by oscillating voltages are reported. The main goal is the modeling of the plasma interaction with the Faraday bars surrounding the antennas during ion cyclotron tokamak heating. The study of the time-averaged potentials shows that the two-dimensional sheath structure depends on both the sheath length-to-thickness ratio and the inclination of the magnetic lines. The equipotential surfaces form closed, nested cells between adjacent bars. When the magnetic lines are nearly perpendicular to the potential gradients, the ion motion is dominated by the ExB drift, and ion streamlines form vortices around the equipotentials. At larger inclinations of the magnetic lines, the flow decouples from the equipotentials and ion transport is mainly along the potential gradients. The critical angle for the transition from vortex circulation to field aligned flow is computed. The effects of the cross-field ion transport on the sheath properties are discussed. It is shown that the sheath length and the magnetic line inclination affect the sheath scaling in the two-dimensional case. The one-dimensional theory results are recovered in the limit of high length-to-thickness ratio and large inclination of the magnetic lines

The Tubular Sheaths Encasing Methanosaeta thermophila Filaments Are Functional Amyloids.

Science.gov (United States)

Dueholm, Morten S; Larsen, Poul; Finster, Kai; Stenvang, Marcel R; Christiansen, Gunna; Vad, Brian S; Bøggild, Andreas; Otzen, Daniel E; Nielsen, Per Halkjær

2015-08-14

Archaea are renowned for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes that are extremely resistant to chemical and thermal denaturation and that resist proteolysis by common proteases. Here we employ amyloid-specific conformation antibodies and biophysical techniques to show that the extracellular cell wall sheaths encasing the methanogenic archaea Methanosaeta thermophila PT are functional amyloids. Depolymerization of sheaths and subsequent MS/MS analyses revealed that the sheaths are composed of a single major sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid nature explains the extreme resistance of the sheath, the elastic properties that allow diffusible substrates to penetrate through expandable hoop boundaries, and how the sheaths are able to split and elongate outside the cell. The archaeal sheath amyloids do not share homology with any of the currently known functional amyloids and clearly represent a new function of the amyloid protein fold. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Malignant Peripheral Nerve Sheath Tumour of the Maxilla

Directory of Open Access Journals (Sweden)

Puja Sahai

2014-01-01

Full Text Available A 38-year-old man was diagnosed with malignant peripheral nerve sheath tumour of the maxilla. He was treated with total maxillectomy. Histopathological examination of the resected specimen revealed a close resection margin. The tumour was of high grade with an MIB-1 labelling index of almost 60%. At six weeks following the surgery, he developed local tumour relapse. The patient succumbed to the disease at five months from the time of diagnosis. The present report underlines the locally aggressive nature of malignant peripheral nerve sheath tumour of the maxilla which necessitates an early therapeutic intervention. A complete resection with clear margins is the most important prognostic factor for malignant peripheral nerve sheath tumour in the head and neck region. Adjuvant radiotherapy may be considered to improve the local control. Future research may demarcate the role of targeted therapy for patients with malignant peripheral nerve sheath tumour.

Zircaloy sheathed thermocouples for PWR fuel rod temperature measurements

International Nuclear Information System (INIS)

Anderson, J.V.; Wesley, R.D.; Wilkins, S.C.

1979-01-01

Small diameter zircaloy sheathed thermocouples have been developed by EG and G Idaho, Inc., at the Idaho National Engineering Laboratory. Surface mounted thermocouples were developed to measure the temperature of zircaloy clad fuel rods used in the Thermal Fuels Behavior Program (TFBP), and embedded thermocouples were developed for use by the Loss-of-Fluid Test (LOFT) Program for support tests using zircaloy clad electrically heated nuclear fuel rod simulators. The first objective of this developmental effort was to produce zircaloy sheathed thermocouples to replace titanium sheathed thermocouples and thereby eliminate the long-term corrosion of the titanium-to-zircaloy attachment weld. The second objective was to reduce the sheath diameter to obtain faster thermal response and minimize cladding temperature disturbance due to thermocouple attachment

Significance of rice sheath photosynthesis: Yield determination by ...

African Journals Online (AJOL)

Using high-yielding hybrid rice Liangyopeijiu (LYP9), its male parent 9311 and hybrid rice Shanyou 63 (SY63) as the experimental materials, the photosynthesis of rice sheath was studied by 14C radio-autography. The results showed that rice sheath could trap sunlight and produce photosynthates, and these ...

Revisiting the plasma sheath—dust in plasma sheath

Energy Technology Data Exchange (ETDEWEB)

Das, G. C. [Mathematical Science Division, IASST, Guwahati 781014 (India); Deka, R.; Bora, M. P., E-mail: mpbora@gauhati.ac.in [Physics Department, Gauhati University, Guwahati 781014 (India)

2016-04-15

In this work, we have considered the formation of warm plasma sheath in the vicinity of a wall in a plasma with considerable presence of dust particles. As an example, we have used the parameters relevant in case of plasma sheath formed around surfaces of various solid bodies in space, though the results obtained in this work can be applied to any other physical situation such as laboratory plasma. In the ion-acoustic time scale, we neglect the dust dynamics. The dust particles affect the sheath dynamics by affecting the Poisson equation which determines the plasma potential in the sheath region. It is important to note that our calculations are valid only when the amount of dust particles is not sufficient so as to affect the plasma dynamics in the dust-acoustic time scale, but enough to affect the plasma sheath. We have assumed the current to a dust particle to be balanced throughout the analysis. This makes the grain potential dependent on plasma potential, which is then incorporated into the Poisson equation. The resultant numerical model becomes an initial value problem, which is described by a 1-D integro-differential equation, which is then solved self-consistently by incorporating the change in plasma potential caused by inclusion of the dust potential in the Poisson equation.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp [Kwasan and Hida Observatories, Kyoto University, Yamashina, Kyoto 607–8471 (Japan)

2017-03-10

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

International Nuclear Information System (INIS)

Takahashi, Takuya; Shibata, Kazunari

2017-01-01

Fast interplanetary coronal mass ejections (ICMEs) are the drivers of strong space weather storms such as solar energetic particle events and geomagnetic storms. The connection between the space-weather-impacting solar wind disturbances associated with fast ICMEs at Earth and the characteristics of causative energetic CMEs observed near the Sun is a key question in the study of space weather storms, as well as in the development of practical space weather prediction. Such shock-driving fast ICMEs usually expand at supersonic speeds during the propagation, resulting in the continuous accumulation of shocked sheath plasma ahead. In this paper, we propose a “sheath-accumulating propagation” (SAP) model that describes the coevolution of the interplanetary sheath and decelerating ICME ejecta by taking into account the process of upstream solar wind plasma accumulation within the sheath region. Based on the SAP model, we discuss (1) ICME deceleration characteristics; (2) the fundamental condition for fast ICMEs at Earth; (3) the thickness of interplanetary sheaths; (4) arrival time prediction; and (5) the super-intense geomagnetic storms associated with huge solar flares. We quantitatively show that not only the speed but also the mass of the CME are crucial for discussing the above five points. The similarities and differences between the SAP model, the drag-based model, and the“snow-plow” model proposed by Tappin are also discussed.

Experimental test of models of radio-frequency plasma sheaths

International Nuclear Information System (INIS)

Sobolewski, M.A.

1997-01-01

The ion current and sheath impedance were measured at the radio-frequency-powered electrode of an asymmetric, capacitively coupled plasma reactor, for discharges in argon at 1.33 endash 133 Pa. The measurements were used to test the models of the radio frequency sheath derived by Lieberman [IEEE Trans. Plasma Sci. 17, 338 (1989)] and Godyak and Sternberg [Phys. Rev. A 42, 2299 (1990)], and establish the range of pressure and sheath voltage in which they are valid. copyright 1997 American Institute of Physics

Studies on the transmission of sub-THz waves in magnetized inhomogeneous plasma sheath

Science.gov (United States)

Yuan, Kai; Shen, Linfang; Yao, Ming; Deng, Xiaohua; Chen, Zhou; Hong, Lujun

2018-01-01

There have been many studies on the sub-terahertz (sub-THz) wave transmission in reentry plasma sheaths. However, only some of them have paid attention to the transmission of sub-THz waves in magnetized plasma sheaths. In this paper, the transmission of sub-THz waves in both unmagnetized and magnetized reentry plasma sheaths was investigated. The impacts of temporal evolution of the plasma sheath on the wave transmission were studied. The transmission of "atmospheric window" frequencies in a magnetized plasma sheath was discussed in detail. According to the study, the power transmission rates (Tp) for the left hand circular (LHC) and the right hand circular modes in the magnetized plasma sheath are obviously higher and lower than those in the unmagnetized plasma sheath, respectively. The Tp of LHC mode increases with both wave frequency and external magnetic field strength. Also, the Tp of LHC mode in both magnetized and unmagnetized plasma sheaths varies with time due to the temporal evolution of the plasma sheath. Moreover, the performance of sub-THz waves in magnetized plasma sheath hints at a new approach to the "blackout" problem. The new approach, which is in the capability of modern technology, is to utilize the communication system operating at 140 GHz with an onboard magnet installed near the antenna.

Isolation of New Gravitropic Mutants under Hypergravity Conditions.

Science.gov (United States)

Mori, Akiko; Toyota, Masatsugu; Shimada, Masayoshi; Mekata, Mika; Kurata, Tetsuya; Tasaka, Masao; Morita, Miyo T

2016-01-01

Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upward. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes). In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using next-generation sequencing (NGS) and single nucleotide polymorphism (SNP)-based markers. Using the endodermal-amyloplast less 1 ( eal1 ) mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g) restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene ( enhancer of eal1 ) mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis .

Fabrication and use of zircaloy/tantalum-sheathed cladding thermocouples and molybdenum/rhenium-sheathed fuel centerline thermocouples

International Nuclear Information System (INIS)

Wilkins, S.C.; Sepold, L.K.

1985-01-01

The thermocouples described in this report are zircaloy/tantalum-sheathed and molybdenum/rhenium alloy-sheathed instruments intended for fuel rod cladding and fuel centerline temperature measurements, respectively. Both types incorporate beryllium oxide insulation and tungsten/rhenium alloy thermoelements. These thermocouples, operated at temperatures of 2000 0 C and above, were developed for use in the internationally sponsored Severe Fuel Damage test series in the Power Burst Facility. The fabrication steps for both thermocouple types are described in detail. A laser-welding attachment technique for the cladding-type thermocouple is presented, and experience with alternate materials for cladding and fuel therocouples is discussed

An investigation of tendon sheathing filler migration into concrete

International Nuclear Information System (INIS)

Naus, D.J.; Oland, C.B.

1998-03-01

During some of the inspections at nuclear power plants with prestressed concrete containments, it was observed that the containments has experienced leakage of the tendon sheathing filler (i.e., streaks). The objective of this activity was to provide an indication of the extent of tendon sheathing filler leakage into the concrete and its affects on concrete properties. Literature was reviewed and concrete core samples were obtained from the Trojan Nuclear Plant and tested. The literature primarily addressed effects of crude or lubricating oils that are known to cause concrete damage. However, these materials have significantly different characteristics relative to the materials used as tendon sheathing fillers. Examination and testing of the concrete cores indicated that the appearance of tendon sheathing filler on the concrete surface was due to leakage from the conduits and its subsequent migration through cracks that were present. Migration of the tendon sheathing filler was confined to the cracks and there was no perceptible movement into the concrete. Results of compressive strength testing indicated that the concrete quality was consistent in the containment and that the strength had increased over 40% in 25.4 years relative to the average compressive strength at 28-days age

Structural Conservation of the Myoviridae Phage Tail Sheath Protein Fold

Energy Technology Data Exchange (ETDEWEB)

Aksyuk, Anastasia A.; Kurochkina, Lidia P.; Fokine, Andrei; Forouhar, Farhad; Mesyanzhinov, Vadim V.; Tong, Liang; Rossmann, Michael G. (SOIBC); (Purdue); (Columbia)

2012-02-21

Bacteriophage phiKZ is a giant phage that infects Pseudomonas aeruginosa, a human pathogen. The phiKZ virion consists of a 1450 {angstrom} diameter icosahedral head and a 2000 {angstrom}-long contractile tail. The structure of the whole virus was previously reported, showing that its tail organization in the extended state is similar to the well-studied Myovirus bacteriophage T4 tail. The crystal structure of a tail sheath protein fragment of phiKZ was determined to 2.4 {angstrom} resolution. Furthermore, crystal structures of two prophage tail sheath proteins were determined to 1.9 and 3.3 {angstrom} resolution. Despite low sequence identity between these proteins, all of these structures have a similar fold. The crystal structure of the phiKZ tail sheath protein has been fitted into cryo-electron-microscopy reconstructions of the extended tail sheath and of a polysheath. The structural rearrangement of the phiKZ tail sheath contraction was found to be similar to that of phage T4.

ICME-driven sheath regions deplete the outer radiation belt electrons

Science.gov (United States)

Hietala, H.; Kilpua, E. K.; Turner, D. L.

2013-12-01

It is an outstanding question in space weather and solar wind-magnetosphere interaction studies, why some storms result in an increase of the outer radiation belt electron fluxes, while others deplete them or produce no change. One approach to this problem is to look at differences in the storm drivers. Traditionally drivers have been classified to Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs). However, an 'ICME event' is a complex structure: The core is a magnetic cloud (MC; a clear flux rope structure). If the mass ejection is fast enough, it can drive a shock in front of it. This leads to the formation of a sheath region between the interplanetary shock and the leading edge of the MC. While both the sheath and the MC feature elevated solar wind speed, their other properties are very different. For instance, the sheath region has typically a much higher dynamic pressure than the magnetic cloud. Moreover, the sheath region has a high power in magnetic field and dynamic pressure Ultra Low Frequency (ULF) range fluctuations, while the MC is characterised by an extremely smooth magnetic field. Magnetic clouds have been recognised as important drivers magnetospheric activity since they can comprise long periods of very large southward Interplanetary Magnetic Field (IMF). Nevertheless, previous studies have shown that sheath regions can also act as storm drivers. In this study, we analyse the effects of ICME-driven sheath regions on the relativistic electron fluxes observed by GOES satellites on the geostationary orbit. We perform a superposed epoch analysis of 31 sheath regions from solar cycle 23. Our results show that the sheaths cause an approximately one order of magnitude decrease in the 24h-averaged electron fluxes. Typically the fluxes also stay below the pre-event level for more than two days. Further analysis reveals that the decrease does not depend on, e.g., whether the sheath interval contains predominantly northward

Electric sheath and presheath in a collisionless, finite ion temperature plasma

International Nuclear Information System (INIS)

Emmert, G.A.; Wieland, R.M.; Mense, A.T.; Davidson, J.N.

1980-01-01

The plasma-sheath equation for a collisionless plasma with arbitrary ion temperature in plane geometry is formulated. Outside the sheath, this equation is approximated by the plasma equation, for which an analytic solution for the electrostatic potential is obtained. In addition, the ion distribution function, the wall potential, and the ion energy and particle flux into the sheath are explicitly calculated. The plasma-sheath equation is also solved numerically with no approximation of the Debye length. The numerical results compare well with the analytical results when the Debye length is small

Atomic Structure of Type VI Contractile Sheath from Pseudomonas aeruginosa.

Science.gov (United States)

Salih, Osman; He, Shaoda; Planamente, Sara; Stach, Lasse; MacDonald, James T; Manoli, Eleni; Scheres, Sjors H W; Filloux, Alain; Freemont, Paul S

2018-02-06

Pseudomonas aeruginosa has three type VI secretion systems (T6SSs), H1-, H2-, and H3-T6SS, each belonging to a distinct group. The two T6SS components, TssB/VipA and TssC/VipB, assemble to form tubules that conserve structural/functional homology with tail sheaths of contractile bacteriophages and pyocins. Here, we used cryoelectron microscopy to solve the structure of the H1-T6SS P. aeruginosa TssB1C1 sheath at 3.3 Å resolution. Our structure allowed us to resolve some features of the T6SS sheath that were not resolved in the Vibrio cholerae VipAB and Francisella tularensis IglAB structures. Comparison with sheath structures from other contractile machines, including T4 phage and R-type pyocins, provides a better understanding of how these systems have conserved similar functions/mechanisms despite evolution. We used the P. aeruginosa R2 pyocin as a structural template to build an atomic model of the TssB1C1 sheath in its extended conformation, allowing us to propose a coiled-spring-like mechanism for T6SS sheath contraction. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Gene Expression Profiling of the Intact Dermal Sheath Cup of Human Hair Follicles.

Science.gov (United States)

Niiyama, Shiro; Ishimatsu-Tsuji, Yumiko; Nakazawa, Yosuke; Yoshida, Yuzo; Soma, Tsutomu; Ideta, Ritsuro; Mukai, Hideki; Kishimoto, Jiro

2018-04-24

Cells that constitute the dermal papillae of hair follicles might be derived from the dermal sheath, the peribulbar component of which is the dermal sheath cup. The dermal sheath cup is thought to include the progenitor cells of the dermal papillae and possesses hair inductive potential; however, it has not yet been well characterized. This study investigated the gene expression profile of the intact dermal sheath cup, and identified dermal sheath cup signature genes, including extracellular matrix components and BMP-binding molecules, as well as TGF-b1 as an upstream regulator. Among these, GREM2, a member of the BMP antagonists, was found by in situ hybridization to be highly specific to the dermal sheath cup, implying that GREM2 is a key molecule contributing to maintenance of the properties of the dermal sheath cup.

Compression test of cold-formedsteel perforated profile with steel sheathing

Directory of Open Access Journals (Sweden)

Shamanin Aleksandr Yur’evich

2015-05-01

Full Text Available The subject of this paper is the stability and strength of cold-formed and perforated steel sigma-section columns with steel sheathing of different thickness. Ceilings with and without steel sheathing of different thickness are tested to failure in compression on a laboratory machine, which was based on a manual hydraulic jack. Series of 4 experiments with full-scale walls (2.5 m height were carried out. Also, for examination of the role of boundary conditions, the sheet in a ceiling is either left free or connected to base with screws.In civil engineering there are many experiments and methodologies for calculating the strength and buckling of ceiling with the sheathing of various materials, such as oriented strand board and gypsum board. However, for producing superstructures of ships the materials with high plastic properties and strength characteristics are required. For example steel possesses such properties. It was the main reason for conducting a series of experiments and studying the behavior of cold-formed steel columns with steel sheathing. During the experiments the deformation of the cross-section of three equally spaced cross sections was determined, as well as the axial deformation of the central column in the ceiling with steel sheathing.The test results showed the influence of the thickness of sheathing and boundary condition of a sheet on the strength and buckling of ceiling. According to the results of the tests it is necessary to evaluate the impact of the sheathing made of different materials and if necessary to carry out further tests.

Sheath rendezvous method: a novel distal protection technique during endovascular treatment of subclavian artery occlusions.

Science.gov (United States)

Haraguchi, Takuya; Urasawa, Kazushi; Nakama, Tatsuya; Nakagawa, Yuya; Tan, Michinao; Koshida, Ryoji; Sato, Katsuhiko

2016-10-01

To describe an innovative distal protection technique, "sheath rendezvous method", during endovascular treatment for subclavian arterial occlusions. 4.5F and 6F guiding sheath were inserted from left brachial and common femoral artery, respectively. 0.014″ guidewire retrogradely passed through occlusion and into antegrade sheath to establish a pull-through system. 3.0 mm balloon was used to expand occlusion and anchor to deliver retrograde sheath into antegrade one. Both sheaths locked by balloon dilatation crossed occlusion until antegrade sheath passed over lesion. Balloon expandable stent was delivered within antegrade sheath. Sheath was removed, and stent was implanted. We obtained an excellent outcome without complications.

Ultrasonographic findings of pilar sheath acanthoma: A case report

Energy Technology Data Exchange (ETDEWEB)

Kang, Dong Joo; Lee, Sun Joo; Kim, Seong Jin [Inje University College of Medicine, Busan Paik Hospital, Busan (Korea, Republic of)

2017-08-15

Pilar sheath acanthoma is a rare benign follicular hamartoma that presents with a central sinus containing keratinous material and is lined by epithelium. It typically occurs on the face, especially on the upper lip and forehead. In our case, the ultrasound (US) feature of pilar sheath acanthoma revealed a well-defined, oval hypoechoic nodule with hypoechoic capping within the dermis over the medial aspect of the calf. To the best of our knowledge, despite many reports on the clinicopathological aspects of pilar sheath acanthoma, this entity has not been well described in the radiologic literature, and US findings have not been documented.

Benign and malignant neurogenic tumors of nerve sheath origin on FDG PET

International Nuclear Information System (INIS)

Yun, M. J.; Go, D. H.; Yoo, Y. H.; Shin, K. H.; Lee, J. D

2004-01-01

The differentiation between benign and malignant nerve sheath tumors is difficult based on conventional radiological imaging. This study was undertaken to investigate the value of FDG PET in distinguishing benign from malignant neurogenic tumors of nerve sheath origin. We performed a retrospective review of the medical record to select patients with nerve sheath tumors who had underdone FDG PET imaging. Fifteen patients (7F: 8M) with benign or malignant nerve sheath tumors were included in this study. Of the 15 patients, 9 were diagnosed with the known neurofibromatosis type I. A total of 19 nerve sheath tumors were included from the 15 patients. All patients had undergone FDG PET to evaluate for malignant potential of the known lesions. Images of FDG PET were semi-quantitatively analyzed and a region of interest (ROI) was placed over the area of the maximum FDG uptake and an average standardized uptake value was taken for final analysis. There were 5 malignant peripheral nerve sheath tumors, 5 schwannomas, and 9 neurofibromas. The mean SUV was 2 (ranged from 1.6 to 3.3) for schwannomas, 1.3 (0.7 to 2.5) for neurofibromas, and 8.4 (4.6 to 12.2) for malignant peripheral nerve sheath tumors. Of 14 benign tumors, all except one schwannoma showed a SUV less than 3. When a cutoff SUV of 4 was used to differentiate the nerve sheath tumors, all tumors were correctly classified as benign or malignant, respectively. Among the 9 patients diagnosed with neurofibromatosis type I. 4 had malignant peripheral nerve sheath tumors and FDG PET accurately detected all the 4 lesions with malignant transformation. According to our results, FDG PET seems to have a great potential for accurately characterizing benign versus malignant nerve sheath tumors. It appears to be extremely useful for patients with neurofibromatosis to localize the lesion with malignant transformation

Bilateral giant cell tumor of tendon sheath of tendoachilles

Directory of Open Access Journals (Sweden)

Soma Datta

2014-01-01

Full Text Available Giant cell tumor of tendon sheath arises from the synovium of tendon sheaths, joints, or bursae, mostly affects adults between 30 and 50 years of age, and is slightly more common in females. We report the case of a 32-years-old male presenting with pain in both ankles without any history of trauma. On clinical examination, tenderness on both tendoachilles and local thickening were observed. Ultrasonography showed thickening of local tendinous area with increase in anteroposterior diameter, and Doppler demonstrated increased flow in peritendinous area. MRI findings showed that most of the tumor had intermediate signal intensity and portions of the tumor had low signal intensity. Fine needle aspiration cytology confirmed the diagnosis of giant cell tumor of tendon sheath. Excision biopsy was done with no recurrence on five month follow-up. Review of literature did not reveal any similar result; so, bilateral giant cell tumor of tendon sheath of tendoachilles is a rare presentation.

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2014-09-01

The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

Synovial sarcoma mimicking benign peripheral nerve sheath tumor

Energy Technology Data Exchange (ETDEWEB)

Larque, Ana B.; Nielsen, G.P.; Chebib, Ivan [Massachusetts General Hospital and Harvard Medical School, Department of Pathology, Boston, MA (United States); Bredella, Miriam A. [Massachusetts General Hospital and Harvard Medical School, Department of Radiology, Boston, MA (United States)

2017-11-15

To assess the radiographic and clinicopathologic features of synovial sarcoma of the nerve that were clinically or radiologically interpreted as benign peripheral nerve sheath tumor. Five patients with synovial sarcoma arising from the peripheral nerve and interpreted clinically and radiologically as peripheral nerve sheath tumors were identified. Clinicopathologic and imaging features were evaluated. There were three females and two males, ranging in age from 28 to 50 (mean 35.8) years. Most patients (4/5) complained of a mass, discomfort or pain. MR images demonstrated a heterogeneous, enhancing, soft tissue mass contiguous with the neurovascular bundle. On histologic examination, most tumors were monophasic synovial sarcoma (4/5). At the time of surgery, all tumors were noted to arise along or within a peripheral nerve. All patients were alive with no evidence of disease with median follow-up of 44 (range 32-237) months. For comparison, approximately 775 benign peripheral nerve sheath tumors of the extremities were identified during the same time period. Primary synovial sarcoma of the nerve can mimic peripheral nerve sheath tumors clinically and on imaging and should be included in the differential diagnosis for tumors arising from peripheral nerves. (orig.)

Isolation of new gravitropic mutants under hypergravity conditions

Directory of Open Access Journals (Sweden)

Akiko Mori

2016-09-01

Full Text Available Forward genetics is a powerful approach used to link genotypes and phenotypes, and mutant screening/analysis has provided deep insights into many aspects of plant physiology. Gravitropism is a tropistic response in plants, in which hypocotyls and stems sense the direction of gravity and grow upwards. Previous studies of gravitropic mutants have suggested that shoot endodermal cells in Arabidopsis stems and hypocotyls are capable of sensing gravity (i.e., statocytes. In the present study, we report a new screening system using hypergravity conditions to isolate enhancers of gravitropism mutants, and we also describe a rapid and efficient genome mapping method, using Next-Generation Sequencing (NGS and Single Nucleotide Polymorphism (SNP-based markers. Using the endodermal-amyloplast less 1 (eal1 mutant, which exhibits defective development of endodermal cells and gravitropism, we found that hypergravity (10 g restored the reduced gravity responsiveness in eal1 hypocotyls and could, therefore, be used to obtain mutants with further reduction in gravitropism in the eal1 background. Using the new screening system, we successfully isolated six ene (enhancer of eal1 mutants that exhibited little or no gravitropism under hypergravity conditions, and using NGS and map-based cloning with SNP markers, we narrowed down the potential causative genes, which revealed a new genetic network for shoot gravitropism in Arabidopsis.

Properties of plasma sheath with ion temperature in magnetic fusion devices

International Nuclear Information System (INIS)

Liu Jinyuan; Wang Feng; Sun Jizhong

2011-01-01

The plasma sheath properties in a strong magnetic field are investigated in this work using a steady state two-fluid model. The motion of ions is affected heavily by the strong magnetic field in fusion devices; meanwhile, the effect of ion temperature cannot be neglected for the plasma in such devices. A criterion for the plasma sheath in a strong magnetic field, which differs from the well-known Bohm criterion for low temperature plasma sheath, is established theoretically with a fluid model. The fluid model is then solved numerically to obtain detailed sheath information under different ion temperatures, plasma densities, and magnetic field strengths.

Plasma sheath axial phase dynamics in coaxial device

Energy Technology Data Exchange (ETDEWEB)

Soliman, H.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt)); Masoud, M.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt))

1994-10-01

The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.).

Plasma sheath axial phase dynamics in coaxial device

International Nuclear Information System (INIS)

Soliman, H.M.; Masoud, M.M.

1994-01-01

The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.)

Optic Nerve Sheath Mechanics in VIIP Syndrome

Science.gov (United States)

Raykin, Julia; Forte, Taylor E.; Wang, Roy; Feola, Andrew; Samuels, Brian; Myers, Jerry; Nelson, Emily; Gleason, Rudy; Ethier, C. Ross

2016-01-01

Visual Impairment Intracranial Pressure (VIIP) syndrome is a major concern in current space medicine research. While the exact pathology of VIIP is not yet known, it is hypothesized that the microgravity-induced cephalad fluid shift increases intracranial pressure (ICP) and drives remodeling of the optic nerve sheath. To investigate this possibility, we are culturing optic nerve sheath dura mater samples under different pressures and investigating changes in tissue composition. To interpret results from this work, it is essential to first understand the biomechanical response of the optic nerve sheath dura mater to loading. Here, we investigated the effects of mechanical loading on the porcine optic nerve sheath.Porcine optic nerves (number: 6) were obtained immediately after death from a local abattoir. The optic nerve sheath (dura mater) was isolated from the optic nerve proper, leaving a hollow cylinder of connective tissue that was used for biomechanical characterization. We developed a custom mechanical testing system that allowed for unconfined lengthening, twisting, and circumferential distension of the dura mater during inflation and under fixed axial loading. To determine the effects of variations in ICP, the sample was inflated (0-60 millimeters Hg) and circumferential distension was simultaneously recorded. These tests were performed under variable axial loads (0.6 grams - 5.6 grams at increments of 1 gram) by attaching different weights to one end of the dura mater. Results and Conclusions: The samples demonstrated nonlinear behavior, similar to other soft connective tissue (Figure 1). Large increases in diameter were observed at lower transmural pressures (approximately 0 to 5 millimeters Hg), whereas only small diameter changes were observed at higher pressures. Particularly interesting was the existence of a cross-over point at a pressure of approximately 11 millimeters Hg. At this pressure, the same diameter is obtained for all axial loads applied

Malignant peripheral nerve sheath tumour of the bladder associated with neurofibromatosis I.

LENUS (Irish Health Repository)

O'Brien, Julie

2008-12-01

Neurofibromatosis is a hamartomatous disorder of autonomic peripheral nerve sheaths associated with peripheral nerve sheath tumours. Most tumours are neurofibromas; however, the genitourinary system is rarely involved. We present a rare case of a nerve sheath tumour of the bladder in a young patient, which was discovered to be malignant.

AC losses of single-core MgB{sub 2} wires with different metallic sheaths

Energy Technology Data Exchange (ETDEWEB)

Kováč, J., E-mail: elekjkov@savba.sk; Šouc, J.; Kováč, P.; Hušek, I.

2015-12-15

Highlights: • AC losses in single-core MgB{sub 2} wires with different metallic sheaths have been measured. • It has been shown that metallic sheath can affect the measured AC loss considerably. • GlidCop and Stainless Steel have negligible effect to the overall loss. • Strong contribution of eddy currents has been found in the wire with well conductive copper sheath. • Due to Monel sheath AC loss of MgB{sub 2} core is not visible. - Abstract: AC losses of single-core MgB{sub 2} superconductors with different metallic sheaths (Cu, GlidCop, stainless steel and Monel) have been measured and analyzed. These wires were exposed to external magnetic field with frequencies 72 and 144 Hz and amplitudes up to 0.1 T at temperatures ranged from 18 to 40 K. The obtained results have shown that applied metallic sheath can affect the measured AC loss considerably. In the case of GlidCop and Stainless Steel a negligible small effect of metallic sheath was observed. Strong contribution of eddy currents has been found in the wire with well conductive copper sheath. In the case of Monel sheath, the hysteresis loss of magnetic sheath is dominated and AC loss of MgB{sub 2} core is practically not visible.

Multimodal imaging in neurofibromatosis type 1-associated nerve sheath tumors

International Nuclear Information System (INIS)

Salamon, J.; Adam, G.; Mautner, V.F.; Derlin, T.

2015-01-01

Neurofibromatosis type 1 (NF1) is a neurogenetic disorder. Individuals with NF1 may develop a variety of benign and malignant tumors of which peripheral nerve sheath tumors represent the most frequent entity. Plexiform neurofibromas may demonstrate a locally destructive growth pattern, may cause severe symptoms and may undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). Whole-body magnetic resonance imaging (MRI) represents the reference standard for detection of soft tissue tumors in NF1. It allows for identification of individuals with plexiform neurofibromas, for assessment of local tumor extent, and for evaluation of whole-body tumor burden on T2-weighted imaging. Multiparametric MRI may provide a comprehensive characterization of different tissue properties of peripheral nerve sheath tumors, and may identify parameters associated with malignant transformation. Due to the absence of any radiation exposure, whole-body MRI may be used for serial follow-up of individuals with plexiform neurofibromas. 18 F-fluorodeoxyglucose positron-emission-tomography (FDG PET/CT) allows a highly sensitive and specific detection of MPNST, and should be used in case of potential malignant transformation of a peripheral nerve sheath tumor. PET/CT provides a sensitive whole-body tumor staging. The use of contrast-enhanced CT for diagnosis of peripheral nerve sheath tumors is limited to special indications. To obtain the most precise readings, optimized examination protocols and dedicated radiologists and nuclear medicine physicians familiar with the complex and variable morphologies of peripheral nerve sheath tumors are required.

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File list: His.Neu.20.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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Full Text Available His.Neu.10.AllAg.Nerve_Sheath_Neoplasms mm9 Histone Neural Nerve Sheath Neoplasms h...ttp://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Neu.10.AllAg.Nerve_Sheath_Neoplasms.bed ...

Contrast material filling of the peroneal tendon sheath

International Nuclear Information System (INIS)

Zadravecz, Gy.; Grexa, E.

1981-01-01

In case of complaints after fracture of the calcaneus the common sheath of the peroneus tendons was filled up with contrast material. The tendon sheath was punctured Oehind the external ankle. The three-directional radiograms clearly showed the dislocation and compression of the tendons, caused by the exostosis of the calcaneus. The concomitant tendovaginitis caused the complaints. This alteration was observed in 11% of all the calcaneus fractures. (L.E.)

File list: Pol.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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File list: Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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Full Text Available Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms mm9 RNA polymerase Neural Nerve Sheath Neop...lasms http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Neu.05.AllAg.Nerve_Sheath_Neoplasms.bed ...

Verification of high voltage rf capacitive sheath models with particle-in-cell simulations

Science.gov (United States)

Wang, Ying; Lieberman, Michael; Verboncoeur, John

2009-10-01

Collisionless and collisional high voltage rf capacitive sheath models were developed in the late 1980's [1]. Given the external parameters of a single-frequency capacitively coupled discharge, plasma parameters including sheath width, electron and ion temperature, plasma density, power, and ion bombarding energy can be estimated. One-dimensional electrostatic PIC codes XPDP1 [2] and OOPD1 [3] are used to investigate plasma behaviors within rf sheaths and bulk plasma. Electron-neutral collisions only are considered for collisionless sheaths, while ion-neutral collisions are taken into account for collisional sheaths. The collisionless sheath model is verified very well by PIC simulations for the rf current-driven and voltage-driven cases. Results will be reported for collisional sheaths also. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16 (1988) 638; 17 (1989) 338 [2] J. P. Verboncoeur, M. V. Alves, V. Vahedi, and C. K. Birdsall, J. Comp. Phys. 104 (1993) 321 [3] J. P. Verboncoeur, A. B. Langdon and N. T. Gladd, Comp. Phys. Comm. 87 (1995) 199

Evaluation of the Effusion within Biceps Long Head Tendon Sheath Using Ultrasonography

Science.gov (United States)

Park, In; Lee, Hyo-Jin; Kim, Sung-Eun; Bae, Sung-Ho; Lee, Kwang-Yeol; Park, Kwang-Sun

2015-01-01

Background Many shoulder diseases are related to glenohumeral joint synovitis and effusion. The purpose of the present study is to detect effusion within the biceps long head tendon sheath as the sign of glenohumeral joint synovitis using ultrasonography, and to evaluate the clinical meaning of effusion within the biceps long head tendon sheath. Methods A consecutive series of 569 patients who underwent ultrasonography for shoulder pain were reviewed retrospectively and ultimately, 303 patients were included. The authors evaluated the incidence and amount of the effusion within the biceps long head tendon sheath on the ultrasonographic short axis view. Furthermore, the authors evaluated the correlation between the amount of effusion within the biceps long head tendon sheath and the range of motion and the functional score. Results The effusion within the biceps long head tendon sheath was detected in 58.42% of the patients studied: 69.23% in adhesive capsulitis, 56.69% in rotator cuff tear, 41.03% in calcific tendinitis, and 33.33% in biceps tendinitis. The average amount of the effusion within the biceps long head tendon sheath was 1.7 ± 1.6 mm, and it was measured to be the largest in adhesive capsulitis. The amount of effusion within biceps long head tendon sheath showed a moderate to high degree of correlation with the range of motion, and a low degree of correlation with the functional score and visual analogue scale for pain in each type of shoulder disease. Conclusions The effusion within the biceps long head tendon sheath is closely related to the range of motion and clinical scores in patients with painful shoulders. Ultrasonographic detection of the effusion within the biceps long head tendon sheath might be a simple and easy method to evaluate shoulder function. PMID:26330958

Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures

Directory of Open Access Journals (Sweden)

Wei Chen

2016-09-01

Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.

Embedded cladding surface thermocouples on Zircaloy-sheathed heater rods

International Nuclear Information System (INIS)

Wilkins, S.C.

1977-06-01

Titanium-sheathed Type K thermocouples embedded in the cladding wall of zircaloy-sheathed heater rods are described. These thermocouples constitute part of a program intended to characterize the uncertainty of measurements made by surface-mounted cladding thermocouples on nuclear fuel rods. Fabrication and installation detail, and laboratory testing of sample thermocouple installations are included

File list: ALL.Neu.50.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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On the upper bound in the Bohm sheath criterion

Energy Technology Data Exchange (ETDEWEB)

Kotelnikov, I. A., E-mail: I.A.Kotelnikov@inp.nsk.su; Skovorodin, D. I., E-mail: D.I.Skovorodin@inp.nsk.su [Russian Academy of Sciences, Budker Institute of Nuclear Physics, Siberian Branch (Russian Federation)

2016-02-15

The question is discussed about the existence of an upper bound in the Bohm sheath criterion, according to which the Debye sheath at the interface between plasma and a negatively charged electrode is stable only if the ion flow velocity in plasma exceeds the ion sound velocity. It is stated that, with an exception of some artificial ionization models, the Bohm sheath criterion is satisfied as an equality at the lower bound and the ion flow velocity is equal to the speed of sound. In the one-dimensional theory, a supersonic flow appears in an unrealistic model of a localized ion source the size of which is less than the Debye length; however, supersonic flows seem to be possible in the two- and three-dimensional cases. In the available numerical codes used to simulate charged particle sources with a plasma emitter, the presence of the upper bound in the Bohm sheath criterion is not supposed; however, the correspondence with experimental data is usually achieved if the ion flow velocity in plasma is close to the ion sound velocity.

Spontaneous rectus sheath hematoma: The utility of CT angiography

Directory of Open Access Journals (Sweden)

Antonio Pierro, MD

2018-04-01

Full Text Available We described the utility of computed tomography (CT angiography in detection of bleeding vessels for a rapid percutaneous arterial embolization of the spontaneous rectus sheath hematoma. A 70-year-old woman comes to our attention with acute abdominal pain and a low hemoglobin level. An unenhanced CT was performed demonstrating a large rectus sheath hematoma. A conservative management was initially established. Despite this therapy, the abdominal pain increased together with a further decrease of hemoglobin values. A CT angiography was then performed, demonstrating an active bleeding within the hematoma and addressing the patient to a rapid percutaneous arterial embolization. Keywords: Rectus sheath hematoma, Acute abdomen, Arterial embolization, CT angiography, Active bleeding

Reflection of ion acoustic waves by the plasma sheath

International Nuclear Information System (INIS)

Ibrahim, I.; Kuehl, H.H.

1984-01-01

The reflection coefficient R for linear monochromatic ion acoustic waves incident on the transonic layer and sheath from the plasma interior is calculated. The treatment differs from previous analyses in that (1) the exact zero-order ion density and velocity profiles for a planar, bounded plasma are used, and the zero-order charge separation is not neglected, and (2) the first-order quantities near the transonic layer are considered in detail, including first-order charge separation, whereby it is found that no coupling to the beam modes exists, and that the functional form of the first-order solution is completely determined. It is shown that the upper bound for Vertical BarRVertical Bar is (1)/(3) . The largest reflection occurs for frequencies which are small compared with the ionization frequency, and generally decreases with increasing frequency. By Fourier superposition, the reflection of a pulse is computed. For a narrow incident pulse, the reflected pulse is greatly distorted and is small compared with the incident pulse. For a broad pulse, the reflected pulse is similar in shape to the incident pulse, and has a magnitude which is approximately (1)/(3) of the incident pulse

Slow-wave propagation and sheath interaction in the ion-cyclotron frequency range

International Nuclear Information System (INIS)

Myra, J R; D'Ippolito, D A

2010-01-01

In previous work (Myra J R and D'Ippolito D A 2008 Phys. Rev. Lett. 101 195004) we studied the propagation of slow-wave (SW) resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the treatment of SW propagation and sheath interaction to 'dense' scrape-off-layer plasmas where the usual cold-plasma SW is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the SW couples to a sheath-plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length. The conditions for avoiding potentially deleterious rf-wall interactions in tokamak rf heating experiments are summarized.

Comparison of a fuel sheath failure model with published experimental data

International Nuclear Information System (INIS)

Varty, R.L.; Rosinger, H.E.

1982-01-01

A fuel sheath failure model has been compared with the published results of experiments in which a Zircaloy-4 fuel sheath was subjected to a temperature ramp and a differential pressure until failure occurred. The model assumes that the deformation of the sheath is controlled by steady-state creep and that there is a relationship between tangential stress and temperature at the instant of failure. The sheath failure model predictions agree reasonably well with the experimental data. The burst temperature is slightly overpredicted by the model. The burst strain is overpredicted for small experimental burst strains but is underpredicted otherwise. The reasons for these trends are discussed and the extremely wide variation in burst strain reported in the literature is explained using the model

Rf sheaths and impurity generation by ICRF [ion cyclotron range of frequencies] antennas

International Nuclear Information System (INIS)

Perkins, F.W.

1988-11-01

In general, Faraday screen elements in an ICRF antenna are not aligned precisely along the combined toroidal and poloidal magnetic fields. When plasma of density n > 2ε 0 V/eg 2 /approximately/ 10 9 cm -3 is present in the gap between elements, electron response to the parallel electric field shorts out the electric field over most of the gap, leaving a narrow sheath of positive space charge and intense electric field. Here V denotes the voltage across the gap and g the gap spacing. This intense electric field accelerates ions up to an appreciable fraction of the gap voltage (/approximately/ 1 kV), sufficient to cause physical sputtering of the screen material. Impurities so generated constitute the principal limitation on power density (kW/cm 2 ) for ICRF antennas. ICRF antenna and Faraday screen design principles which minimize sputtering are discussed. 24 refs., 9 figs., 1 tab

The collisional capacitive RF sheath and the assumption of a sharp electron edge

Science.gov (United States)

Brinkmann, Ralf Peter

2008-10-01

The transition from quasi-neutrality to charge depletion is one of the characteristic features of the plasma boundary sheath. It is often described in terms of the so-called step model which assumes a transition point (electron step) where the electron density drops from a value equal to the ion density (in the bulk) to a value of zero (in the sheath). Inserted into Poisson's equation, the step model yields an expression for the field which is realistic deep in the sheath but fails to merge correctly into the ambipolar field of the bulk. This work studies the consequences of that approximation for the example of the collision-dominated, capacitive RF sheath by Lieberman [1]. First, the model is solved exactly, using a relaxation scheme. Then, the step approximation is applied which recovers Lieberman's semi-analytical solution. It is demonstrated that the step approximation induces a spurious divergence of the ion density at the sheath edge and prevents a matching of the sheath model to a bulk model. Integral sheath quantities, on the other hand, like the capacitance or the overall voltage drop, are faithfully reproduced. [1] M. A. Lieberman, IEEE Trans. Plasma Sci. 16, pp. 638-644 (1988).

Theoretical and computational studies of the sheath of a planar wall

Science.gov (United States)

Giraudo, Martina; Camporeale, Enrico; Delzanno, Gian Luca; Lapenta, Giovanni

2012-03-01

We present an investigation of the stability and nonlinear evolution of the sheath of a planar wall. We focus on the electrostatic limit. The stability analysis is conducted with a fluid model where continuity and momentum equations for the electrons and ions are coupled through Poisson's equation. The effect of electron emission from the wall is studied parametrically. Our results show that a sheath instability associated with the emitted electrons can exist. Following Ref. [1], it is interpreted as a Rayleigh-Taylor instability driven by the favorable combination of the sheath electron density gradient and electric field. Fully kinetic Particle-In-Cell (PIC) simulations will also be presented to investigate whether this instability indeed exists and to study the nonlinear effect of electron emission on the sheath profiles. The simulations will be conducted with CPIC, a new electrostatic PIC code that couples the standard PIC algorithm with strategies for generation and adaptation of the computational grid. [4pt] [1] G.L. Delzanno, ``A paradigm for the stability of the plasma sheath against fluid perturbations,'' Phys. Plasmas 18, 103508 (2011).

Dynamics of Dust in a Plasma Sheath with Magnetic Field

International Nuclear Information System (INIS)

Duan Ping; Liu Jinyuan; Gon Ye; Liu Yue; Wang Xiaogang

2007-01-01

Dynamics of dust in a plasma sheath with a magnetic field was investigated using a single particle model. The result shows that the radius, initial position, initial velocity of the dust particles and the magnetic field do effect their movement and equilibrium position in the plasma sheath. Generally, the dust particles with the same size, whatever original velocity and position they have, will locate at the same position in the end under the net actions of electrostatic, gravitational, neutral collisional, and Lorentz forces. But the dust particles will not locate in the plasma sheath if their radius is beyond a certain value

Coronal mass ejections and their sheath regions in interplanetary space

Science.gov (United States)

Kilpua, Emilia; Koskinen, Hannu E. J.; Pulkkinen, Tuija I.

2017-11-01

Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

Coronal mass ejections and their sheath regions in interplanetary space

Directory of Open Access Journals (Sweden)

Emilia Kilpua

2017-11-01

Full Text Available Abstract Interplanetary coronal mass ejections (ICMEs are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

Anode Sheath Switching in a Carbon Nanotube Arc Plasma

International Nuclear Information System (INIS)

Fetterman, Abe; Raitses, Yevgeny; Keidar, Michael

2008-01-01

The anode ablation rate is investigated as a function of anode diameter for a carbon nanotube arc plasma. It is found that anomalously high ablation occurs for small anode diameters. This result is explained by the formation of a positive anode sheath. The increased ablation rate due to this positive anode sheath could imply greater production rate for carbon nanotubes.

Fibroma of the tendon sheath of the long head of the biceps tendon

International Nuclear Information System (INIS)

Maeseneer, Michel de; Shahabpour, Maryam; Isacker, Tom van; Lenchik, Leon; Caillie, Marie-Astrid van

2014-01-01

Fibroma of the tendon sheath is a benign tumor that is less common than giant cell tumor of the tendon sheath. Both tumors may present as a painless, slowly enlarging mass. Radiological findings may be similar for both tumors. Histologically, fibroma of the tendon sheath lacks the hemosiderin-laden macrophages that are typical for giant cell tumor of the tendon sheath. We report on a 49-year-old woman with fibroma of the tendon sheath of the long head of the biceps tendon. In our case, on MR images, we observed band-like hypointense areas centrally in the tumor, mild patchy contrast enhancement, and most importantly, no decrease of signal intensity on gradient echo images. These characteristics reflected histological findings. (orig.)

The anatomy of the first sacral nerve root sheath shown by computed tomography.

Science.gov (United States)

Moore, N R; Dixon, A K; Freer, C E

1989-08-01

Analysis of 25 patients with normal computed tomographic appearances at the lumbosacral junction revealed wide variation in the anatomical level at which the first sacral nerve root sheaths were seen emerging from the theca. In nine patients (36%), the S1 nerve root sheaths were first recognized at the level of the lumbosacral disc. In 14 patients (56%), the sheaths emerged cranial to the disc; it is possible that these patients may be more prone to neurological complications related to disc or facet joint disease, especially if the sheath is laterally sited within the lateral recess. Conversely, that minority of patients (two, 8%) in whom the root sheaths emerge caudal to the disc level may be relatively protected from neurological complications.

Effects of Reentry Plasma Sheath on GPS Patch Antenna Polarization Property

Directory of Open Access Journals (Sweden)

L. Zhao

2013-01-01

Full Text Available A plasma sheath enveloping a reentry vehicle would affect performances of on-board antenna greatly, especially the navigation antennas. This paper studies the effects of reentry plasma sheath on a GPS right-hand circularly polarized (RHCP patch antenna polarization property during a typical reentry process. Utilizing the algorithm of finite integration technique, the polarization characteristic of a GPS antenna coated by a plasma sheath is obtained. Results show that the GPS RHCP patch antenna radiation pattern distortions as well as polarization deteriorations exist during the entire reentry process, and the worst polarization mismatch loss between a GPS antenna and RHCP GPS signal is nearly 3 dB. This paper also indicates that measures should be taken to alleviate the plasma sheath for maintaining the GPS communication during the reentry process.

Internal pressure effects in the AIRCO-LCT conductor sheath

International Nuclear Information System (INIS)

Luton, J.N.; Clinard, J.A.; Lue, J.W.; Gray, W.H.; Summers, L.T.; Kershaw, R.

1985-01-01

The large Nb 3 Sn superconducting test coil produced by Westinghouse Electric Corporation for the international Large Coil Task (LCT) utilizes a conductor composed of cabled multifilamentary strands immersed in flowing supercritical helium contained by a square structural sheath made of the high-strength stainless alloy JBX-75. Peak pressures of a few hundred atmospheres are predicted to occur during quench, and measurement of these pressures seems feasible only through penetrations of the sheath wall. Fully processed short lengths of conductor were taken from production ends, fitted with pressure taps and strain gauges, and pressurized with helium gas. Failure, at 1000 atm at liquid nitrogen temperature, was by a catastrophic splitting of the sheath at a corner. Strain measurements and burst pressure agreed with elastic-plastic finite element stress calculations made for the sheath alone. Neither the production seam weld nor the pressure tap penetrations or their fillet welds contributed to the failure, although the finite element calculations show that these areas were also highly stressed, and examination of the failed sample showed that the finite welds were of poor quality. Failure was by tensile overload, with no evidence of fatigue

Somatostatin Receptor SPECT/CT using 99mTc Labeled HYNIC-TOC Aids in Diagnosis of Primary Optic Nerve Sheath Meningioma.

Science.gov (United States)

Chandra, Piyush; Purandare, Nilendu; Shah, Sneha; Agrawal, Archi; Rangarajan, Venkatesh

2017-01-01

Primary optic nerve sheath meningiomas (ONSM) are rare, benign and slow growing tumor involving the intra-orbital/intra-canalicular segment of the optic nerve. Untreated, they can potentially lead to visual deterioration. Magnetic resonance (MR) is the gold standard imaging modality for diagnosing the entity. Often, a clinical dilemma exists to narrow the differential diagnosis of an enhancing intra-orbital mass on MR. Molecular imaging provides a high degree of precision in diagnosing meningioma in view of relatively high levels of somatostatin receptor expression by these tumors. The following case demonstrates the potential clinical utility of somatostatin receptor SPECT using 99m Tc- labeled HYNIC-TOC in clinical diagnosis of ONSM.

Hertwig’s Epithelial Root Sheath Fate during Initial Cellular Cementogenesis in Rat Molars

International Nuclear Information System (INIS)

Yamamoto, Tsuneyuki; Yamada, Tamaki; Yamamoto, Tomomaya; Hasegawa, Tomoka; Hongo, Hiromi; Oda, Kimimitsu; Amizuka, Norio

2015-01-01

To elucidate the fate of the epithelial root sheath during initial cellular cementogenesis, we examined developing maxillary first molars of rats by immunohistochemistry for keratin, vimentin, and tissue non-specific alkaline phosphatase (TNALP) and by TdT-mediated dUTP nick end labeling (TUNEL). The advancing root end was divided into three sections, which follow three distinct stages of initial cellular cementogenesis: section 1, where the epithelial sheath is intact; section 2, where the epithelial sheath becomes fragmented; and section 3, where initial cellular cementogenesis begins. After fragmentation of the epithelial sheath, many keratin-positive epithelial sheath cells were embedded in the rapidly growing cellular cementum. A few unembedded epithelial cells located on the cementum surface. Dental follicle cells, precementoblasts, and cementoblasts showed immunoreactivity for vimentin and TNALP. In all three sections, there were virtually no cells possessing double immunoreactivity for vimentin-keratin or TNALP-keratin and only embedded epithelial cells showed TUNEL reactivity. Taken together, these findings suggest that: (1) epithelial sheath cells divide into two groups; one group is embedded in the cementum and thereafter dies by apoptosis, and the other survives on the cementum surface as epithelial cell rests of Malassez; and (2) epithelial sheath cells do not undergo epithelial-mesenchymal transition during initial cellular cementogenesis

Unirradiated UO2 in irradiated zirconium alloy sheathing

International Nuclear Information System (INIS)

MacDonald, R.D.; Hardy, D.G.; Hunt, C.E.L.; Scoberg, J.A.

1979-07-01

Zircaloy-clad UO 2 fuel elements have defected in power reactors when element power outputs were raised significantly after a long irradiation at low power. We have irradiated fuel elements fabricated from fresh UO 2 pellets and zirconium alloy sheaths previously irradiated without fuel. This gave a fuel element with radiation-damaged low-ductility sheathing but with no fission products in the fuel. The elements were power boosted in-reactor to linear power outputs up to 84 kW/m for two five-day periods. No elements defected despite sheath strains of 0.82 percent at circumferential ridge postions. Half of these elements were subsequently soaked at low power to build up the fission product inventory in the fuel and then power boosted to 63 kW/m for a third time. Two elements defected on this final boost. We conclude that these defects were caused by fission product induced stress-corrosion cracking and that this mechanism plays an importent role in power reactor fuel defects. (auth)

Balloon sheaths for gastrointestinal guidance and access: a preliminary phantom study

International Nuclear Information System (INIS)

He, Xu; Shin, Ji Hoon; Kim, Hyo Cheol; Woo, Cheol Woong; Woo, Sung Ha; Choi, Won Chan; Kim, Jong Gyu; Lim, Jin Oh; Kim, Tae Hyung; Yoon, Chang Jin; Song, Ho Young; Kang, Wee Chang

2005-01-01

We wanted to evaluate the feasibility and usefulness of a newly designed balloon sheath for gastrointestinal guidance and access by conducting a phantom study. The newly designed balloon sheath consisted of an introducer sheath and a supporting balloon. A coil catheter was advanced over a guide wire into two gastroduodenal phantoms (one was with stricture and one was without stricture); group I was without a balloon sheath, group II was with a deflated balloon sheath, and groups III and IV were with an inflated balloon and with the balloon in the fundus and body, respectively. Each test was performed for 2 minutes and it was repeated 10 times in each group by two researchers, and the positions reached by the catheter tip were recorded. Both researchers had better performances with both phantoms in order of group IV, III, II and I. In group IV, both researchers advanced the catheter tip through the fourth duodenal segment in both the phantoms. In group I, however, the catheter tip never reached the third duodenal segment in both the phantoms by both the researchers. The numeric values for the four study groups were significantly different for both the phantoms (ρ < 0.001). A significant difference was also found between group III and IV for both phantoms (ρ < 0.001). The balloon sheath seems to be feasible for clinical use, and it has good clinical potential for gastrointestinal guidance and access, particularly when the inflated balloon is placed in the gastric body

Ontogeny of the sheathing leaf base in maize (Zea mays).

Science.gov (United States)

Johnston, Robyn; Leiboff, Samuel; Scanlon, Michael J

2015-01-01

Leaves develop from the shoot apical meristem (SAM) via recruitment of leaf founder cells. Unlike eudicots, most monocot leaves display parallel venation and sheathing bases wherein the margins overlap the stem. Here we utilized computed tomography (CT) imaging, localization of PIN-FORMED1 (PIN1) auxin transport proteins, and in situ hybridization of leaf developmental transcripts to analyze the ontogeny of monocot leaf morphology in maize (Zea mays). CT imaging of whole-mounted shoot apices illustrates the plastochron-specific stages during initiation of the basal sheath margins from the tubular disc of insertion (DOI). PIN1 localizations identify basipetal auxin transport in the SAM L1 layer at the site of leaf initiation, a process that continues reiteratively during later recruitment of lateral leaf domains. Refinement of these auxin transport domains results in multiple, parallel provascular strands within the initiating primordium. By contrast, auxin is transported from the L2 toward the L1 at the developing margins of the leaf sheath. Transcripts involved in organ boundary formation and dorsiventral patterning accumulate within the DOI, preceding the outgrowth of the overlapping margins of the sheathing leaf base. We suggest a model wherein sheathing bases and parallel veins are both patterned via the extended recruitment of lateral maize leaf domains from the SAM. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

File list: NoD.Neu.05.AllAg.Nerve_Sheath_Neoplasms [Chip-atlas[Archive

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The Tubular Sheaths Encasing Methanosaeta and Methanospirillum Filaments are Functional Amyloids

DEFF Research Database (Denmark)

Dueholm, Morten Simonsen; Larsen, Poul; Nielsen, Per Halkjær

Archaea are well-recognized for their ability to thrive in extreme environments, although they can be found in virtually all habitats. Their adaptive success is linked to their unique cell envelopes, which often display extremely resistant to chemical and thermal denaturation and resist proteolysis...... techniques to show that the extracellular cell wall sheaths of the methanogenic archaea Methanosaeta and Methanospirillum are functional amyloid structures. Depolymerization of sheaths with formic acid and reducing agents and subsequent MS/MS analysis revealed that the sheaths are composed of a single major...... sheath protein (MspA). The amyloidogenic nature of MspA was confirmed by in vitro amyloid formation of recombinant MspA under a wide range of environmental conditions. This is the first report of a functional amyloid from the archaeal domain of life. The amyloid properties explain the extreme resistance...

Selective pH-Responsive Core-Sheath Nanofiber Membranes for Chem/Bio/Med Applications: Targeted Delivery of Functional Molecules.

Science.gov (United States)

Han, Daewoo; Steckl, Andrew J

2017-12-13

Core-sheath fibers using different Eudragit materials were successfully produced, and their controlled multi-pH responses have been demonstrated. Core-sheath fibers made of Eudragit L 100 (EL100) core and Eudragit S 100 (ES100) sheath provide protection and/or controlled release of core material at pH 6 by adjusting the sheath thickness (controlled by the flow rate of source polymer solution). The thickest sheath (∼250 nm) provides the least core release ∼1.25%/h, while the thinnest sheath (∼140 nm) provides much quicker release ∼16.75%/h. Furthermore, switching core and sheath material dramatically altered the pH response. Core-sheath fibers made of ES100 core and EL100 sheath can provide a consistent core release rate, while the sheath release rate becomes higher as the sheath layer becomes thinner. For example, the thinnest sheath (∼120 nm) provides a core and sheath release ratio of 1:2.5, while the thickest sheath (∼200 nm) shows only a ratio of 1:1.7. All core-sheath Eudragit fibers show no noticeable release at pH 5, while they are completely dissolved at pH 7. Extremely high surface area in the porous network of the fiber membranes provides much faster (>30 times) response to external pH changes as compared to that of equivalent cast films.

Effects of an anode sheath on energy and momentum transfer in vacuum arcs

International Nuclear Information System (INIS)

Wang, Zhenxing; Zhou, Zhipeng; Tian, Yunbo; Wang, Haoran; Wang, Jianhua; Geng, Yingsan; Liu, Zhiyuan

2017-01-01

Anode phenomena under high-current vacuum arcs have a significant impact on the interrupting capacity of vacuum interrupters. However, the vacuum arc energy flux and momentum flux on the anode—which are necessary boundary conditions for simulations—are either set to an imaginary distribution or calculated using simple formulas without considering anode sheath regulatory effects. The objective of this paper is to reveal the anode sheath effects on regulating the energy and momentum transfer from the arc column to the anode surface in vacuum arcs. A particle-in-cell model for the anode sheath is developed. The required input parameters are obtained from a magnetohydrodynamic model for the arc column. From the results, there exists a sheath near the anode with a negative voltage drop. Both the electron density and the ion density significantly decline in the anode sheath region. The kinetic energy of the ions absorbed by the anode consists of directed kinetic energy, random kinetic energy, and sheath acceleration energy. The sheath acceleration energy contribution is the largest, and the random kinetic energy also accounts for a large part that cannot be ignored. The arc pressure on the anode surface is mainly caused by ion impact, and the accelerating effect of the anode sheath on the ions cannot be neglected in pressure calculations. In addition, in the case of an arc current at 15 kA, the input energy and momentum upon the anode surface is not obviously affected by the evaporated atoms at surface temperatures of 1600 K and 2000 K. (paper)

Can using a peel-away sheath in shunt implantation prevent ventricular catheter obstruction?

Science.gov (United States)

Camlar, Mahmut; Ersahin, Yusuf; Ozer, Fusun Demirçivi; Sen, Fatih; Orman, Mehmet

2011-02-01

Shunt obstruction is the most common shunt complication. In 2003, Kehler et al. used peel-away sheath while implanting the ventricular catheter in 20 patients. They found less revision rate in the peel-away sheath group. We aimed to test the efficacy of this technique in cadavers. We used 100 fresh brains obtained from medicolegal autopsies. Posterior parietal and frontal approaches were used to puncture the lateral ventricle in each cerebral hemisphere. The ventricle is punctured with a peel-away sheath system. After the ventricle is reached, the mandarin is retracted and the ventricular catheter is introduced through the opening. The ventricular catheter was removed from the ventricle, the opening at the tip of the ventricular catheter was checked out for obstruction, and the number of patent and plugged openings was recorded. This procedure was repeated four times for each location with and without using peel-away sheath. The control group consisted of the procedures done without using peel-away sheath. The number of the plugged openings in the peel-away sheath group was significantly smaller than the control group. There was no significant difference between the two groups in terms of gender and left and right cerebral hemispheres. The obstruction rate was significantly lower in the posterior parietal approach. Pearson's correlation showed that increasing age was associated with less obstruction rate. Peel-away sheath decreases the number of plugged openings of the ventricular catheter. A clinical cooperative study is needed to prove that a peel-away sheath should be included in the ventricular shunt systems in the market.

Slow Wave Propagation and Sheath Interaction for ICRF Waves in the Tokamak SOL

International Nuclear Information System (INIS)

Myra, J. R.; D'Ippolito, D. A.

2009-01-01

In previous work we studied the propagation of slow-wave resonance cones launched parasitically by a fast-wave antenna into a tenuous magnetized plasma. Here we extend the previous calculation to ''dense'' scrape-off-layer (SOL) plasmas where the usual slow wave is evanescent. Using the sheath boundary condition, it is shown that for sufficiently close limiters, the slow wave couples to a sheath plasma wave and is no longer evanescent, but radially propagating. A self-consistent calculation of the rf-sheath width yields the resulting sheath voltage in terms of the amplitude of the launched SW, plasma parameters and connection length.

Optic Nerve Sheath Meningocele: A Case Report

Science.gov (United States)

Halimi, E.; Wavreille, O.; Rosenberg, R.; Bouacha, I.; Lejeune, J.-P.; Defoort-Dhellemmes, S.

2013-01-01

Abstract Isolated optic nerve sheath meningocele is a rare affection defined as the cystic enlargement of the optic nerve sheath filled with cerebrospinal fluid. We report the case of a 39-year-old woman presenting with bilateral meningocele uncovered during a routine examination for headache complaints. A 5-year follow-up validated the lesion’s clinical and imaging stability. Magnetic resonance imaging (MRI) is an essential tool in the diagnosis of this pathology, alongside characteristic symptoms indicating that the meningocele might have progressively expanded into the orbit. In this case we present a therapeutic approach based on pathophysiological hypotheses and review of the literature. PMID:28163760

Characterization of a null allelic mutant of the rice NAL1 gene reveals its role in regulating cell division.

Directory of Open Access Journals (Sweden)

Dan Jiang

Full Text Available Leaf morphology is closely associated with cell division. In rice, mutations in Narrow leaf 1 (NAL1 show narrow leaf phenotypes. Previous studies have shown that NAL1 plays a role in regulating vein patterning and increasing grain yield in indica cultivars, but its role in leaf growth and development remains unknown. In this report, we characterized two allelic mutants of NARROW LEAF1 (NAL1, nal1-2 and nal1-3, both of which showed a 50% reduction in leaf width and length, as well as a dwarf culm. Longitudinal and transverse histological analyses of leaves and internodes revealed that cell division was suppressed in the anticlinal orientation but enhanced in the periclinal orientation in the mutants, while cell size remained unaltered. In addition to defects in cell proliferation, the mutants showed abnormal midrib in leaves. Map-based cloning revealed that nal1-2 is a null allelic mutant of NAL1 since both the whole promoter and a 404-bp fragment in the first exon of NAL1 were deleted, and that a 6-bp fragment was deleted in the mutant nal1-3. We demonstrated that NAL1 functions in the regulation of cell division as early as during leaf primordia initiation. The altered transcript level of G1- and S-phase-specific genes suggested that NAL1 affects cell cycle regulation. Heterogeneous expression of NAL1 in fission yeast (Schizosaccharomyces pombe further supported that NAL1 affects cell division. These results suggest that NAL1 controls leaf width and plant height through its effects on cell division.

The relative axial expansions under irradiation of stacks of UO{sub 2} pellets in zircaloy sheaths

Energy Technology Data Exchange (ETDEWEB)

Notley, M. J.F.

1962-08-15

An experiment was performed to measure the relative axial movement of UO{sub 2} fuel pellets inside a Zircaloy sheath. Although the results must be treated with some reservation, the inferences are that there is very little relative movement between the fuel and the sheath when the two are in firm pressure contact. Relative movement was in the range 0.075 {+-} 0.03 cm for a 30 cm fuel length, and was not greatly affected by the power output, profile of the pellet end-faces or the diametral clearance left between the fuel and the sheath on assembly. However in two elements that had thick sheaths to withstand the coolant pressure and that were assembled with large diametral clearances (2% of the diameter) the available axial clearance for relative fuel/ sheath movement (1%) was fully taken up. The thin sheathed elements showed residual axial expansions of up to 0.17 cm, indicating that the pellets move relative to the sheath only until frictional forces are sufficient for the sheath to grip the fuel; thereafter the sheath is extended. The measurements also indicate that sheath elongation is governed by the temperature at the contact points between adjacent pellets, eg. at the inner edge of a pellet shoulder, as long as that temperature is below approximately 1000{sup o}C. At higher temperatures, the UO{sub 2} is too plastic to exert sufficient force to strain the sheath. (author)

The endomembrane sheath: a key structure for understanding the plant cell?

Science.gov (United States)

Reuzeau, C.; McNally, J. G.; Pickard, B. G.

1997-01-01

Recent evidence suggests that integrin is abundant in endomembranes of plant cells, and the endomembranes are clad by a sheath of cytoskeleton including F-actin. A role for endomembrane integrin and the endomembrane sheath is proposed: this system might orchestrate metabolic regulation by providing and modulating loci for channelling, and might accelerate channeling as needed by dragging the endoplasmic reticulum (ER) and organelles through the cytoplasm. To accomplish this "streaming", F-actin might lever against the rest of the endomembrane sheath and the ER might also lever against adhesion sites (i.e., plasmodesmata and plasmalemmal control centers). As an important agent in the control of cellular activities, according to this model, the endomembrane sheath would play a major part in responses to diverse signals and stresses, and under extreme stress cell survival would depend on the ability of the system to maintain enough integrity to direct critical syntheses and degradations.

Dust crystal in the electrode sheath of a gaseous discharge

International Nuclear Information System (INIS)

Schweigert, I.V.; Schweigert, V.A.

2002-01-01

The phenomena observed in strongly coupled dusty plasmas in the electrode sheath of gas discharge clearly indicate that the screened Coulomb potential is not valid for inter-particle interaction. The reason why the conventional model breaks down is clear now. The strong electric field, accelerating ions toward the cathode, leads to an asymmetrical particle shielding and the appearance of an attractive component in the inter-particle force. The sheath plasma with micro-particles is non Hamiltonian system because of input of energy from ion flux from the bulk plasma. The models of interaction potential of microparticles in sheath are proposed. The first is the linear effective positive charge (EPC). On the basis of this model the stability of the dust crystal in the sheath is analyzed both analytically and in MD simulations. The scenario of crystal melting is described. The role of different types of defects in the local heating of the crystal is considered. The next non-linear model of sheath plasma with micro-particles allows to find all parameter of plasma crystal: particle charge, inter-particle distance and study the structural transition. We constructed the analytical expression for inter-particle potential and have found the mechanism acceleration of extra particle beneath the monolayer. Recently new more simple analytical kinetic approach, accounting for ion collisions, have been developed. The structural transition in the dust molecular was obtained in simulation with multipole expansion model interaction potential

Dissociation and Re-Aggregation of Multicell-Ensheathed Fragments Responsible for Rapid Production of Massive Clumps of Leptothrix Sheaths

Science.gov (United States)

Kunoh, Tatsuki; Nagaoka, Noriyuki; McFarlane, Ian R.; Tamura, Katsunori; El-Naggar, Mohamed Y.; Kunoh, Hitoshi; Takada, Jun

2016-01-01

Species of the Fe/Mn-oxidizing bacteria Leptothrix produce tremendous amounts of microtubular, Fe/Mn-encrusted sheaths within a few days in outwells of groundwater that can rapidly clog water systems. To understand this mode of rapid sheath production and define the timescales involved, behaviors of sheath-forming Leptothrix sp. strain OUMS1 were examined using time-lapse video at the initial stage of sheath formation. OUMS1 formed clumps of tangled sheaths. Electron microscopy confirmed the presence of a thin layer of bacterial exopolymer fibrils around catenulate cells (corresponding to the immature sheath). In time-lapse videos, numerous sheath filaments that extended from the periphery of sheath clumps repeatedly fragmented at the apex of the same fragment, the fragments then aggregated and again elongated, eventually forming a large sheath clump comprising tangled sheaths within two days. In this study, we found that fast microscopic fragmentation, dissociation, re-aggregation and re-elongation events are the basis of the rapid, massive production of Leptothrix sheaths typically observed at macroscopic scales. PMID:27490579

Floating fat in the wrist joint and in the tendon sheaths

Energy Technology Data Exchange (ETDEWEB)

Le Corroller, Thomas; Zink, Jean-Vincent; Champsaur, Pierre [Hopital Sainte-Marguerite, Radiology Department, Marseille (France); Parratte, Sebastien; Argenson, Jean-Noel [Hopital Sainte-Marguerite, Orthopaedic Surgery Department, Marseille (France)

2010-09-15

A traumatic fat effusion in a tendon sheath is an unreported entity. We report on the clinical and imaging features, including radiography and computed tomography (CT), of a fat-density effusion in the wrist joint and tendon sheaths of the extensor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis in a 28-year-old patient after a roller-skating accident. Radiographs showed a fracture of the distal radius and a wrist joint effusion. Preoperative CT examination exhibited two distinct layers resulting in a fat-fluid level pathognomonic of lipohemarthrosis in the radiocarpal joint. In addition, a fat-density effusion was noted in the sheaths of the second and third compartment extensor tendons. The lipohemarthrosis depicted on imaging classically results from the extrusion of fat from bone marrow into the joint space after an intraarticular fracture. Similarly, a traumatic fat effusion in a tendon sheath presents characteristic imaging features that may help to diagnose a potentially overlooked fracture. (orig.)

Floating fat in the wrist joint and in the tendon sheaths

International Nuclear Information System (INIS)

Le Corroller, Thomas; Zink, Jean-Vincent; Champsaur, Pierre; Parratte, Sebastien; Argenson, Jean-Noel

2010-01-01

A traumatic fat effusion in a tendon sheath is an unreported entity. We report on the clinical and imaging features, including radiography and computed tomography (CT), of a fat-density effusion in the wrist joint and tendon sheaths of the extensor pollicis longus, extensor carpi radialis longus, and extensor carpi radialis brevis in a 28-year-old patient after a roller-skating accident. Radiographs showed a fracture of the distal radius and a wrist joint effusion. Preoperative CT examination exhibited two distinct layers resulting in a fat-fluid level pathognomonic of lipohemarthrosis in the radiocarpal joint. In addition, a fat-density effusion was noted in the sheaths of the second and third compartment extensor tendons. The lipohemarthrosis depicted on imaging classically results from the extrusion of fat from bone marrow into the joint space after an intraarticular fracture. Similarly, a traumatic fat effusion in a tendon sheath presents characteristic imaging features that may help to diagnose a potentially overlooked fracture. (orig.)

Experimental Studies of Anode Sheath Phenomena in a Hall Thruster Discharge

International Nuclear Information System (INIS)

Dorf, L.; Raitses, Y.; Fisch, N.J.

2004-01-01

Both electron-repelling and electron-attracting anode sheaths in a Hall thruster were characterized by measuring the plasma potential with biased and emissive probes [L. Dorf, Y. Raitses, V. Semenov, and N.J. Fisch, Appl. Phys. Let. 84 (2004) 1070]. In the present work, two-dimensional structures of the plasma potential, electron temperature, and plasma density in the near-anode region of a Hall thruster with clean and dielectrically coated anodes are identified. Possible mechanisms of anode sheath formation in a Hall thruster are analyzed. The path for current closure to the anode appears to be the determining factor in the anode sheath formation process. The main conclusion of this work is that the anode sheath formation in Hall thrusters differs essentially from that in the other gas discharge devices, like a glow discharge or a hollow anode, because the Hall thruster utilizes long electron residence times to ionize rather than high neutral pressures

Anomalous Capacitive Sheath with Deep Radio Frequency Electric Field Penetration

International Nuclear Information System (INIS)

Kaganovich, Igor D.

2002-01-01

A novel nonlinear effect of anomalously deep penetration of an external radio-frequency electric field into a plasma is described. A self-consistent kinetic treatment reveals a transition region between the sheath and the plasma. Because of the electron velocity modulation in the sheath, bunches in the energetic electron density are formed in the transition region adjusted to the sheath. The width of the region is of order V(subscript T)/omega, where V(subscript T) is the electron thermal velocity, and w is frequency of the electric field. The presence of the electric field in the transition region results in a cooling of the energetic electrons and an additional heating of the cold electrons in comparison with the case when the transition region is neglected

Electric fields in the sheath formed in a 300 mm, dual frequency capacitive argon discharge

International Nuclear Information System (INIS)

Barnat, E V; Miller, P A; Hebner, G A; Paterson, A M; Panagopoulos, T; Hammond, E; Holland, J

2007-01-01

The spatial structure and temporal evolution of the electric fields in a sheath formed in a dual frequency, 300 mm capacitive argon discharge are measured as functions of relative mixing between a low frequency current and a high frequency current. It is found that the overall structure of the sheath (potential across the sheath and the thickness of the sheath) are dominated by the lower frequency component while (smaller) oscillations in these quantities are dictated by the higher frequency component. Comparisons of the measured spatial and temporal profiles are made for Lieberman's and Robiche et al sheath model and with a particle in a cell calculation

30 CFR 15.32 - Tolerances for weight of explosive, sheath, wrapper, and specific gravity.

Science.gov (United States)

2010-07-01

..., wrapper, and specific gravity. 15.32 Section 15.32 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION... explosive, sheath, wrapper, and specific gravity. (a) The weight of the explosive, the sheath, and the outer.... (c) The specific gravity of the explosive and sheath shall be within ±7.5 percent of that specified...

Effect of electron emission on an ion sheath structure

International Nuclear Information System (INIS)

Mishra, M K; Phukan, A; Chakraborty, M

2014-01-01

This article reports on the variations of ion sheath structures due to the emission of both hot and cold electrons in the target plasma region of a double plasma device. The ion sheath is produced in front of a negatively biased plate. The plasma is produced by hot filament discharge in the source region, and no discharge is created in the target region of the device. The plate is placed in the target (diffused plasma) region where cold electron emitting filaments are present. These cold electrons are free from maintenance of discharge, which is sustained in the source region. The hot ionizing electrons are present in the source region. Three important parameters are changed by both hot and cold electrons i.e. plasma density, plasma potential and electron temperature. The decrease in plasma potential and the increase in plasma density lead to the contraction of the sheath. (paper)

Accounting for Debye sheath expansion for proud Langmuir probes in magnetic confinement fusion plasmas.

Science.gov (United States)

Tsui, C K; Boedo, J A; Stangeby, P C

2018-01-01

A Child-Langmuir law-based method for accounting for Debye sheath expansion while fitting the current-voltage I-V characteristic of proud Langmuir probes (electrodes that extend into the volume of the plasma) is described. For Langmuir probes of a typical size used in tokamak plasmas, these new estimates of electron temperature and ion saturation current density values decreased by up to 60% compared to methods that did not account for sheath expansion. Changes to the collection area are modeled using the Child-Langmuir law and effective expansion perimeter l p , and the model is thus referred to as the "perimeter sheath expansion method." l p is determined solely from electrode geometry, so the method may be employed without prior measurement of the magnitude of the sheath expansion effects for a given Langmuir probe and can be used for electrodes of different geometries. This method correctly predicts the non-saturating ΔI/ΔV slope for cold, low-density plasmas where sheath-expansion effects are strong, as well as for hot plasmas where ΔI/ΔV ∼ 0, though it is shown that the sheath can still significantly affect the collection area in these hot conditions. The perimeter sheath expansion method has several advantages compared to methods where the non-saturating current is fitted: (1) It is more resilient to scatter in the I-V characteristics observed in turbulent plasmas. (2) It is able to separate the contributions to the ΔI/ΔV slope from sheath expansion to that of the high energy electron tail in high Te conditions. (3) It calculates the change in the collection area due to the Debye sheath for conditions where ΔI/ΔV ∼ 0 and for V = V f .

Soil sheaths, photosynthate distribution to roots, and rhizosphere water relations for Opuntia ficus-indica

Energy Technology Data Exchange (ETDEWEB)

Huang, B.; North, G.B.; Nobel, P.S. (Univ. of California, Los Angeles, CA (United States))

1993-09-01

Soil sheaths incorporating aggregated soil particles surround young roots of many species, but the effects of such sheaths on water movement between roots and the soil are largely unknown. The quantity and location of root exudates associated with soil sheath along the entire length of its young roots, except within 1.4 cm of the tip. The soil sheaths, which average 0.7 mm in thickness, were composed of soil particles and root hairs, both of which were covered with exuded mucilaginous material. As determined with a [sup 14]C pulse-labeling technique, 2% of newly fixed [sup 14]C-photosynthate was translocated into the roots at 3d, 6% at 9 d, and 8% at 15 d after labeling. The fraction of insoluble [sup 14]C in the roots increased twofold from 3 d to 15 d. Over the same time period, 6%-9% of the [sup 14]C translocated to the roots was exuded into the soil. The soluble [sup 14]C compounds exuded into the soil were greater in the 3-cm segment at the root tip than elsewhere along the root, whereas mucilage was exuded relatively uniformly along roots 15 cm in length. The volumetric efflux of water increase for both sheathed and unsheathed roots as the soil water potential decreased form -0.1 MPa to -1.0 MPa. The efflux rate was greater for unsheathed roots than for sheathed roots, which were more turgid and had a higher water potential, especially at lower soil water potentials. During drying, soil particles in the sheaths aggregate more tightly, making the sheaths less permeable to water and possibly creating air gaps. The soil sheaths of O. ficus-indica thus reduce water loss from the roots to a drying soil. 34 refs., 6 figs., 1 tab.

Ion clusters, REB, and current sheath characteristics in focused discharges

International Nuclear Information System (INIS)

Bortolotti, A.; Brzosko, J.; DeChiara, P.; Kilic, H.; Mezzetti, F.; Nardi, V.; Powell, C.; Zeng, D.

1990-01-01

Small fluctuations in the current sheath characteristics (peak current density, FWHM of leading sheath, control parameters of sheath internal structure) are linked to wide fluctuations of ion and ion cluster emission from the pinch. Magnetic probe data are used for correlating variations of current sheath parameters with particle emission intensity, Z/M composition, particle energy spectrum. The emission of ion and ion clusters at 90 degrees from the axis of a plasma focus discharge is monitored simultaneously with the 0 degrees emission. The particle energy spectrum is analyzed with a Thomson (parabola) spectrometer (time resolution ∼ 1 nanosec). The cross-sectional structure of the REB at 180 degrees along the discharge axis is monitored via the deposition of collective-field accelerated ions on a target in the REB direction. Etched tracks of ion and ion clusters are in all cases recorded on CR-39 plates. Sharp peaks of the D + -ion spectrum at 90 degrees are found for E > 200 keV/unit charge in all focused discharges. These peaks are due to ion crossing of the azimuthal magnetic field of the pinch region, in a predominant ion cluster structure

Influence of vacuum space on formation of potential sheath in plasmas

International Nuclear Information System (INIS)

Uhm, H.S.

1997-01-01

Properties of potential sheaths developed in plasmas are investigated in terms of the plasma Debye length and the dimension of vacuum space. Biased plasma potential and the potential profile depend very sensitively on the geometrical configuration of plasma and vacuum space. The potential sheath is never developed near electrodes in high-density plasmas where the Debye length is much less than the dimension of the vacuum space. In this case, most of the potential drops occur in the vacuum space and almost no electric field exists inside the plasma. Parametric investigation of the potential sheath in terms of the vacuum-space and plasma dimensions is carried out. (orig.)

Photovoltaic building sheathing element with anti-slide features

Science.gov (United States)

Keenihan, James R.; Langmaid, Joseph A.; Lopez, Leonardo C.

2015-09-08

The present invention is premised` upon an assembly that includes at least a photovoltaic building sheathing element capable of being affixed on a building structure, the photovoltaic building sheathing element. The element including a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; and at feast a first and a second connector assembly capable of directly or indirectly electrically connecting the photovoltaic cell assembly to one or more adjoining devices; wherein the body portion includes one or more geometric features adapted to engage a vertically adjoining device before installation.

Sheathed electrical resistance heaters for nuclear or other specialized service - approved 1973

International Nuclear Information System (INIS)

Anon.

1976-01-01

This specification presents the requirements for cylindrical metal-sheathed, electrical resistance heaters with compacted mineral-oxide insulation for nuclear or other specialized service. The intended use of a sheathed heater in a specific nuclear or general application will require an evaluation by the purchaser of the compatibility of the heater assembly in the proposed application including the effects of the integrated proposed application including the effects of the integrated neutron flux, temperature, and atmosphere on the properties of the materials of construction. This specification does not include all possible specifications, standards, etc. for materials that may be used in sheathing, insulation, resistance wire, or conductors wire in nuclear environments. The requirements of this specification include only the austenitic stainless steels and nickel-based alloys for sheathing; magnesium oxide, aluminum oxide, beryllium oxide for insulation; and nickel-chromium or iron-chromium-aluminum heater elements with or without low-resistance connecting wires. The intent of this specification is to present the requirements for heaters capable of operating at sheath temperatures and heat fluxes that will limit the maximum internal heater-element temperature to 1050 0 C

RF-sheath assessment of ICRF antenna geometry for long pulses

International Nuclear Information System (INIS)

Colas, L.; Bremond, S.

2003-01-01

Monitoring powered ion cyclotron resonance frequency (ICRF) antennas in magnetic fusion devices has revealed localized modifications of the plasma edge in the antenna shadow, most of them probably related to an enhanced polarization of the scrape-off layer (SOL) through radio-frequency (RF) sheath rectification. Although tolerable on present short RF pulses, sheaths should be minimized, as they may hinder proper operation of steady-state antennas and other subsystems connected magnetically to them, such as lower hybrid grills. As a first step towards mitigating RF sheaths in the design of future antennas, the present paper analyses the spatial structure of sheath potential maps in their vicinity, in relation with the 3D topology of RF near fields and the geometry of antenna front faces. Various combinations of poloidal radiating straps are first considered, and results are confronted to those inferred from transmission line theory. The dependence of sheath potentials on RF voltages or RF currents is studied. The role of RF near-field symmetries along tilted field lines is stressed to interpret such effects as that of strap phasing. A generalization of the 'dipole effect' is proposed. With similar arguments, the behavior of Faraday screen corners, where hot spots concentrate on Tore-Supra (TS), is then studied. The merits of aligning the antenna structure with the tilted magnetic field are thus discussed. The effect of switching from TS (high RF voltage near corners) to ITER-like electrical configurations of the straps (high voltage near equatorial plane) is also analyzed. (authors)

Levitation and dynamics of a collection of dust particles in a fully ionized plasma sheath

International Nuclear Information System (INIS)

Nitter, T.; Aslaksen, T.K.; Melandsoe, F.; Havnes, O.

1994-01-01

The authors have examined the dynamics of a collection of charged dust particles in the plasma sheath above a large body in a fully ionized space plasma when the radius of the large body is much larger than the sheath thickness. The dust particles are charged by the plasma, and the forces on the dust particles are assumed to be from the electric field in the sheath and from gravitation only. These forces will often act in opposite direction and may balance, making dust suspension and collection possible. The dust particles are supplied by injection or by electrostatic levitation. The ability of the sheath to collect dust particles, will be optimal for a certain combination of gravitation and plasma and dust particle parameters. In a dense dust sheath, the charges on the dust particles contribute significantly to the total space charge, and collective effects become important. These effects will reduce the magnitude of the sheath electric field strength and the charge on the dust particles. As dust particles are collected, the dust sheath is stretched and the largest dust particles may drop out, because the sheath is no longer able to suspend them. In a tenuous dust sheath, the inner layer, from the surface and about one Debye length thick, will be unstable for dust particle motion, and dust will not collect there. In a dense dust sheath, collective effects will decrease the thickness of this inner dust-free layer, making dust collection closer to the surface possible. By linearization of the force and current equations, they find the necessary and sufficient conditions which resemble those of planetary system bodies, but the results may also be of relevance to some laboratory plasmas

Benign Peripheral Nerve Sheath Tumor in a Wild Toco Toucan ( Ramphastos toco ).

Science.gov (United States)

Carvalho, Marcelo P N; Fernandes, Natalia C C A; Nemer, Viviane C; Neto, Ramiro N Dias; Teixeira, Rodrigo H F; Miranda, Bruna S; Mamprim, Maria J; Catão-Dias, José L; Réssio, Rodrigo A

2016-09-01

Peripheral nerve sheath tumors are a heterogeneous group of neoplasms that comprise neurofibromas, schwannomas, neurilemmomas, and perineuromas. In animals, peripheral nerve sheath neoplasms are most commonly diagnosed in dogs and cattle, followed by horses, goats, and cats, but their occurrence is uncommon in birds. An adult, free-living, male toco (common) toucan ( Ramphastos toco ) was admitted to the zoo animal clinic with weight loss, dehydration, and presence of a soft nodule adhered to the medial portion of the left pectoral muscle. Clinical, cytologic, and computed tomography scan results were indicative of a neoplasm. The toucan died during surgical resection of the mass. Necropsy, histopathologic, and immunohistochemical findings confirmed the diagnosis of benign peripheral nerve sheath tumor. To our knowledge, benign peripheral nerve sheath tumor has not previously been reported in a toucan or any other species in the order Piciformes.

Anode sheath transition in an anodic arc for synthesis of nanomaterials

Science.gov (United States)

Nemchinsky, V. A.; Raitses, Y.

2016-06-01

The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium.

Anode sheath transition in an anodic arc for synthesis of nanomaterials

International Nuclear Information System (INIS)

Nemchinsky, V A; Raitses, Y

2016-01-01

The arc discharge with ablating anode or so-called anodic arc is widely used for synthesis of nanomaterials, including carbon nanotubes and fullerens, metal nanoparticles etc. We present the model of this arc, which confirms the existence of the two different modes of the arc operation with two different anode sheath regimes, namely, with negative anode sheath and with positive anode sheath. It was previously suggested that these regimes are associated with two different anode ablating modes—low ablation mode with constant ablation rate and the enhanced ablation mode (Fetterman et al 2008 Carbon 46 1322). The transition of the arc operation from low ablation mode to high ablation mode is determined by the current density at the anode. The model can be used to self-consistently determine the distribution of the electric field, electron density and electron temperature in the near-anode region of the arc discharge. Simulations of the carbon arc predict that for low arc ablating modes, the current is driven mainly by the electron diffusion to the anode. For positive anode sheath, the anode voltage is close to the ionization potential of anode material, while for negative anode sheath, the anode voltage is an order of magnitude smaller. It is also shown that the near-anode plasma, is far from the ionization equilibrium. (paper)

The plasma-sheath boundary region

International Nuclear Information System (INIS)

Franklin, R N

2003-01-01

In this review an attempt is made to give a broad coverage of the problem of joining plasma and sheath over a wide range of physical conditions. We go back to the earliest works quoting them, where appropriate, to understand what those who introduced the various terms associated with the structure of the plasma-sheath had in mind. We try to bring out the essence of the insights that have been gained subsequently, by quoting from the literature selectively, indicating how misunderstandings have arisen. In order to make it accessible to the generality of those currently working in low temperature plasmas we have sought to avoid mathematical complexity but retain physical insight, quoting from published work where appropriate. Nevertheless, in clarifying my own ideas I have found it necessary to do additional original work in order to give a consistent picture. In this way I have sought to bring together work in the late 1920s, the 1960s, and now mindful of the commercial importance of plasma processing, work over the past 15 years that adds to the general understanding. (topical review)

Measurement of sheath thickness by lining out grooves in the Hall-type stationary plasma thrusters

International Nuclear Information System (INIS)

Yu Daren; Wu Zhiwen; Ning Zhongxi; Wang Xiaogang

2007-01-01

Using grooves created along the axial direction of the discharge channel, a method for measuring sheath thickness in Hall-type stationary plasma thrusters has been developed. By distorting the wall surface using these grooves, it is possible to numerically study the effect of the wall surface on the sheath and near wall conductivity. Monte Carlo method is applied to calculate the electron temperature variation with different groove depths. The electron dynamic process in the plasma is described by a test particle method with the electron randomly entering the sheath from the discharge channel and being reflected back. Numerical results show that the reflected electron temperature is hardly affected by the wall surface if the groove depth is much less than the sheath thickness. On the other hand, the reflected electron temperature increases if the groove depth is much greater than the sheath thickness. The reflected electron temperature has a sharp jump when the depth of groove is on the order of the sheath thickness. The simulation is repeated with different sheath thicknesses and the results are the same. Therefore, a diagnosis mean of the sheath thickness can be developed based on the method. Also the simulation results are in accord with the experimental data. Besides, the measurement method may be applicable to other plasma device with similar orthogonal steady state electrical and magnetic fields

Durable resistance to net blotch and agronomic performance in some barley mutants [Hordeum vulgare L.; Syria

International Nuclear Information System (INIS)

Arabi, M.I.E.

2004-01-01

Seeds from the net blotch (Pyrenophora teres) susceptible cultivar Thibaut were treated by gamma ray radiation and subsequently evaluated for reaction to the pathogen in the M2-M5 generations. Grain yield and agronomic characteristics of putative mutants were compared with Thibaut in two different locations. Genetic variation among some mutant lines/cv Thibaut was estimated using Amplified Fragment Length Polymorphism (AFLP) markers. Sixteen mutant lines and their mother cultivar Thibaut were analyzed with 14 EcoR1-Mse1 primer combinations. A total number of 504 AFLP bands were analyzed for each pair mutant/Thibaut. Narrow genetic variation among all genotypes was detected with an average of genetic similarity of 0.96. Cluster analysis with the entire AFLP data divided all genotypes into two major groups. The resistant mutant lines were grouped in one subcluster with 0.98 similarity index. Some resistant mutant lines to net blotch with good agronomic performances were produced [it

Statistical analysis of mirror mode waves in sheath regions driven by interplanetary coronal mass ejection

Science.gov (United States)

Ala-Lahti, Matti M.; Kilpua, Emilia K. J.; Dimmock, Andrew P.; Osmane, Adnane; Pulkkinen, Tuija; Souček, Jan

2018-05-01

We present a comprehensive statistical analysis of mirror mode waves and the properties of their plasma surroundings in sheath regions driven by interplanetary coronal mass ejection (ICME). We have constructed a semi-automated method to identify mirror modes from the magnetic field data. We analyze 91 ICME sheath regions from January 1997 to April 2015 using data from the Wind spacecraft. The results imply that similarly to planetary magnetosheaths, mirror modes are also common structures in ICME sheaths. However, they occur almost exclusively as dip-like structures and in mirror stable plasma. We observe mirror modes throughout the sheath, from the bow shock to the ICME leading edge, but their amplitudes are largest closest to the shock. We also find that the shock strength (measured by Alfvén Mach number) is the most important parameter in controlling the occurrence of mirror modes. Our findings suggest that in ICME sheaths the dominant source of free energy for mirror mode generation is the shock compression. We also suggest that mirror modes that are found deeper in the sheath are remnants from earlier times of the sheath evolution, generated also in the vicinity of the shock.

Mitigating impact of thermal and rectified radio-frequency sheath potentials on edge localized modes

Energy Technology Data Exchange (ETDEWEB)

Gui, B. [Institute of Plasma Physics Chinese Academy of Sciences, Hefei (China); Lawerence Livermore National Lab, Livermore, California 94550 (United States); Xu, X. Q. [Lawerence Livermore National Lab, Livermore, California 94550 (United States); Myra, J. R.; D' Ippolito, D. A. [Lodestar Research Corporation, Boulder, Colorado 80301 (United States)

2014-11-15

The mitigating impact of thermal and rectified radio frequency (RF) sheath potentials on the peeling-ballooning modes is studied non-linearly by employing a two-fluid three-field simulation model based on the BOUT++ framework. Additional shear flow and the Kelvin-Helmholtz effect due to the thermal and rectified RF sheath potential are induced. It is found that the shear flow increases the growth rate while the K-H effect decreases the growth rate slightly when there is a density gradient, but the energy loss of these cases is suppressed in the nonlinear phase. The stronger external electrostatic field due to the sheaths has a more significant effect on the energy loss suppression. From this study, it is found the growth rate in the linear phase mainly determines the onset of edge-localized modes, while the mode spectrum width in the nonlinear phase has an important impact on the turbulent transport. The wider mode spectrum leads to weaker turbulent transport and results in a smaller energy loss. Due to the thermal sheath and rectified RF sheath potential in the scrape-off-layer, the modified shear flow tears apart the peeling-ballooning filament and makes the mode spectrum wider, resulting in less energy loss. The perturbed electric potential and the parallel current near the sheath region is also suppressed locally due to the sheath boundary condition.

Moisture Durability with Vapor-Permeable Insulating Sheathing

Energy Technology Data Exchange (ETDEWEB)

Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-09-01

Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However, uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.

Moisture Durability with Vapor-Permeable Insulating Sheathing

Energy Technology Data Exchange (ETDEWEB)

Lepage, R. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-09-01

Exterior sheathing insulation is an effective strategy in increasing the overall R-value of wall assemblies; other benefits include decreasing the effects of thermal bridging and increasing the moisture durability of the built assembly. Vapor-permeable exterior insulation, such as mineral board or expanded polystyrene foam, are one such product that may be used to achieve these benefits. However,uncertainty exists on the effects of inward driven moisture and the interaction of increased sheathing temperatures on the moisture durability of the edifice. To address these concerns, Building Science Corporation (BSC) conducted a series of hygrothermal models for cities representing a range of different climate zones. This report describes the research project, key research questions, and theprocedures utilized to analyse the problems.

Characterization and genetic mapping of eceriferum-ym (cer-ym), a cutin deficient barley mutant with impaired leaf water retention capacity.

Science.gov (United States)

Li, Chao; Liu, Cheng; Ma, Xiaoying; Wang, Aidong; Duan, Ruijun; Nawrath, Christiane; Komatsuda, Takao; Chen, Guoxiong

2015-09-01

The cuticle covers the aerial parts of land plants, where it serves many important functions, including water retention. Here, a recessive cuticle mutant, eceriferum-ym (cer-ym), of Hordeum vulgare L. (barley) showed abnormally glossy spikes, sheaths, and leaves. The cer-ym mutant plant detached from its root system was hypersensitive to desiccation treatment compared with wild type plants, and detached leaves of mutant lost 41.8% of their initial weight after 1 h of dehydration under laboratory conditions, while that of the wild type plants lost only 7.1%. Stomata function was not affected by the mutation, but the mutant leaves showed increased cuticular permeability to water, suggesting a defective leaf cuticle, which was confirmed by toluidine blue staining. The mutant leaves showed a substantial reduction in the amounts of the major cutin monomers and a slight increase in the main wax component, suggesting that the enhanced cuticle permeability was a consequence of cutin deficiency. cer-ym was mapped within a 0.8 cM interval between EST marker AK370363 and AK251484, a pericentromeric region on chromosome 4H. The results indicate that the desiccation sensitivity of cer-ym is caused by a defect in leaf cutin, and that cer-ym is located in a chromosome 4H pericentromeric region.

Cell Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath

Science.gov (United States)

2017-07-01

to subsequently guide tissue regeneration , for example, by seeded tissue progenitor cells . To achieve this objective, the first step is to develop...AWARD NUMBER: W81XWH-15-1-0104 TITLE: Cell -Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath PRINCIPAL INVESTIGATOR...SUBTITLE 5a. CONTRACT NUMBER Cell -Based Meniscal Repair Using an Aligned Bioactive Nanofibrous Sheath 5b. GRANT NUMBER W81XWH-15-1-0104 5c. PROGRAM

The ion polytropic coefficient in a collisionless sheath containing hot ions

Energy Technology Data Exchange (ETDEWEB)

Lin, Binbin; Xiang, Nong, E-mail: xiangn@ipp.ac.cn; Ou, Jing [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Center for Magnetic Fusion Theory, Chinese Academy of Sciences, Hefei 230031 (China)

2016-08-15

The fluid approach has been widely used to study plasma sheath dynamics. For a sheath containing hot ions whose temperature is greater than the electron's, how to truncate the fluid hierarchy chain equations while retaining to the fullest extent of the kinetic effects is always a difficult problem. In this paper, a one-dimensional, collisionless sheath containing hot ions is studied via particle-in-cell simulations. By analyzing the ion energy equation and taking the kinetic effects into account, we have shown that the ion polytropic coefficient in the vicinity of the sheath edge is approximately constant so that the state equation with the modified polytropic coefficient can be used to close the hierarchy chain of the ion fluid equations. The value of the polytropic coefficient strongly depends on the hot ion temperature and its concentration in the plasma. The semi-analytical model is given to interpret the simulation results. As an application, the kinetic effects on the ion saturation current density in the probe theory are discussed.

Rectus sheath haematoma or leaking aortic aneurysm - a diagnostic challenge: a case report

Directory of Open Access Journals (Sweden)

Shaw Aidan G

2009-11-01

Full Text Available Abstract Introduction A rectus sheath haematoma is a rare condition that arises from the accumulation of blood within the rectus sheath from either muscular tear or rupture of the epigastric vessels. It is a known complication of either blunt abdominal trauma, anticoagulation therapy or the repetitive contraction of the rectus muscle such as paroxysms of coughing. It remains an uncommon and elusive entity and is often clinically misdiagnosed. Case presentation An 80-year-old British man with a known aortic aneurysm was admitted with sudden onset of right iliac fossa pain. The patient was hemodynamically stable and underwent a computed tomography scan which revealed an intact aorta and an acute rectus sheath hematoma. Conclusion To the best of our knowledge, no case has previously been reported involving the diagnostic challenge of a rectus sheath hematoma in a patient with a known aortic aneurysm. Here we discuss the symptoms and signs of a rectus sheath hematoma, as well as the radiological modalities that could be utilized to reach the diagnosis.

Development of Ti-sheathed MgB2 wires with high critical current density

International Nuclear Information System (INIS)

Liang, G; Fang, H; Hanna, M; Yen, F; Lv, B; Alessandrini, M; Keith, S; Hoyt, C; Tang, Z; Salama, K

2006-01-01

Working towards developing lightweight superconducting magnets for future space and other applications, we have successfully fabricated mono-core Ti-sheathed MgB 2 wires by the powder-in-tube method. The wires were characterized by magnetization, electrical resistivity, x-ray diffraction, scanning electron microscopy, and energy dispersive spectrometry measurements. The results indicate that the Ti sheath does not react with the magnesium and boron, and the present wire rolling process can produce MgB 2 wires with a superconducting volume fraction of at least 64% in the core. Using the Bean model, it was found that at 5 K, the magnetic critical current densities, J c , measured in magnetic fields of 0, 5, and 8 T are about 4.2 x 10 5 , 3.6 x 10 4 , and 1.4 x 10 4 A cm -2 , respectively. At 20 K and 0 T, the magnetic J c is about 2.4 x 10 5 A cm -2 . These results show that at zero and low fields, the values of the magnetic J c for Ti-sheathed MgB 2 wires are comparable with the best results available for the Fe-sheathed MgB 2 wires. At high fields, however, the J c for Ti-sheathed MgB 2 wires appears higher than that for the Fe-sheathed MgB 2 wires

Research on stress distribution regularity of cement sheaths of radial well based on ABAQUS

Science.gov (United States)

Shi, Jihui; Cheng, Yuanfang; Li, Xiaolong; Xiao, Wen; Li, Menglai

2017-12-01

To ensure desirable outcome of hydraulic fracturing based on ultra-short radius radial systems, it is required to investigate the stress distribution regularity and stability of the cement sheath. On the basis of the theoretical model of the cement sheath stress distribution, a reservoir mechanical model was built using the finite element software, ABAQUS, according to the physical property of a certain oil reservoir of the Shengli oilfield. The stress distribution of the casing-cement-sheath-formation system under the practical condition was simulated, based on which analyses were conducted from multiple points of view. Results show that the stress on the internal interface of the cement sheath exceeds that on the external interface, and fluctuates with higher amplitudes, which means that the internal interface is the most failure-prone. The unevenness of the cement sheath stress distribution grows with the increasing horizontal principal stress ratio, and so does the variation magnitude. This indicates that higher horizontal principal stress ratios are unfavourable for the structural stability of the cement sheath. Both the wellbore quantity of the URRS and the physical property of the material can affect the cement sheath distribution. It is suggested to optimize the quantity of the radial wellbore and use cement with a lower elastic modulus and higher Poisson’s ratio. At last, the impact level of the above factor was analysed, with the help of the grey correlation analysis.

Child-Langmuir law for cathode sheath of glow discharge in CO2

International Nuclear Information System (INIS)

Lisovskiy, V.A.; Krol, H.H.; Osmayev, R.O.; Yegorenkov, V.D.

2016-01-01

This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO 2 . To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions - one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in CO 2 have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility.

Effects of neutral gas collisions on the power transmission factor at the divertor sheath

International Nuclear Information System (INIS)

Futch, A.H.; Matthews, G.F.; Buchenauer, D.; Hill, D.N.; Jong, R.A.; Porter, G.D.

1992-01-01

We show that charge-exchange and other ion-neutral collision can reduce the power transmission factor of the plasma sheath, thereby lowering the ion impact energy and target plate sputtering. The power transmission factor relates the heat flux reaching the divertor target to the plasma density and temperature just in front of the surface: δ=Q surf /J ew k T e . Experimental data from the DIII-D tokamak suggests that δ could be as low as 2-3 near the region of peak divertor particle flux, instead of the 7-8 expected from usual sheath theory. Several effects combine to allow ion-neutral interactions to be important in the divertor plasma sheath. The shallow angle of incidence of the magnetic field (1-3deg in DIII-D) leads to the spatial extension of the sheath from approximately ρ i ∝1 mm normal to the plate to several centimeters along the field lines. Ionization reduces the sheath potential, and collisions reduce the ion impact energy. (orig.)

Effect of rise-time patterns on dynamics of sheath expansion during plasma immersion ion implantation

International Nuclear Information System (INIS)

Huang Yongxian; Tian Xiubo; Yang Shiqin; Fu Ricky; Paul, C.K.

2007-01-01

Plasma immersion ion implantation (PIII) has been developed as a low-cost and efficient surface modification technique of irregularly-shaped objects. The effect of six pulse waves with different rise-time patterns on the spatio-temporal evolution of plasma sheath,energy and dose of ion implantation has been simulated by particle-in-cell modeling. Statistical results may be obtained through assuming the Boltzmann distribution of electrons, and solving Poisson and Newton equations for tracing each ion in the plasma sheath. The results show that rise-time pattern has a critical influence on the evolution of plasma sheath. There exists maximum thickness difference of plasma sheath for different waveforms. The acceleration of ions is non-uniform due to the non-uniformity of electrical field strength. The maximum gradient of electrical field appears near the edge of plasma sheath. The results also show that optimization of dose and energy of incident ions may be achieved through modification of rise-time pattern. The numerical simulation of sheath expansion can be effectively used to provide a scientific basis for optimizing the PIII process. (authors)

Dusty Plasma Modeling of the Fusion Reactor Sheath Including Collisional-Radiative Effects

International Nuclear Information System (INIS)

Dezairi, Aouatif; Samir, Mhamed; Eddahby, Mohamed; Saifaoui, Dennoun; Katsonis, Konstantinos; Berenguer, Chloe

2008-01-01

The structure and the behavior of the sheath in Tokamak collisional plasmas has been studied. The sheath is modeled taking into account the presence of the dust 2 and the effects of the charged particle collisions and radiative processes. The latter may allow for optical diagnostics of the plasma.

Fibrin Sheath Angioplasty: A Technique to Prevent Superior Vena Cava Stenosis Secondary to Dialysis Catheters

Science.gov (United States)

Hacker, Robert I.; Garcia, Lorena De Marco; Chawla, Ankur; Panetta, Thomas F.

2012-01-01

Fibrin sheaths are a heterogeneous matrix of cells and debris that form around catheters and are a known cause of central venous stenosis and catheter failure. A total of 50 cases of central venous catheter fibrin sheath angioplasty (FSA) after catheter removal or exchange are presented. A retrospective review of an outpatient office database identified 70 eligible patients over a 19-month period. After informed consent was obtained, the dialysis catheter exiting the skin was clamped, amputated, and a wire was inserted. The catheter was then removed and a 9-French sheath was inserted into the superior vena cava, a venogram was performed. If a fibrin sheath was present, angioplasty was performed using an 8 × 4 or 10 × 4 balloon along the entire length of the fibrin sheath. A completion venogram was performed to document obliteration of the sheath. During the study, 50 patients were diagnosed with a fibrin sheath, and 43 had no pre-existing central venous stenosis. After FSA, 39 of the 43 patient's (91%) central systems remained patent without the need for subsequent interventions; 3 patients (7%) developed subclavian stenoses requiring repeat angioplasty and stenting; 1 patent (2.3%) developed an occlusion requiring a reintervention. Seven patients with prior central stenosis required multiple angioplasties; five required stenting of their central lesions. Every patient had follow-up fistulograms to document long-term patency. We propose that FSA is a prudent and safe procedure that may help reduce the risk of central venous stenosis from fibrin sheaths due to central venous catheters. PMID:23997555

Arthroscopic sheath design and technical evaluation

NARCIS (Netherlands)

Tuijthof, Gabriëlle J. M.; Blankevoort, Leendert; Herder, Just L.; van Dijk, C. Niek

2009-01-01

The maintenance of a clear view on the operation area is essential to perform a minimally invasive procedure In arthroscopy, this is achieved by irrigating the Joint with a saline fluid that is pumped through the joint At present the arthroscopic sheaths are not designed for optimal irrigation,

Community structure of filamentous, sheath-building sulfur bacteria, Thioploca spp, off the coast of Chile

DEFF Research Database (Denmark)

Schulz, HN; Jørgensen, BB; Fossing, HA

1996-01-01

of Concepcion was investigated,vith respect to biomass, species distribution, and three-dimensional orientation of the sheaths, Thioploca sheaths and filaments were found across the whole shelf area within the oxygen minimum zone, The maximum wet weight of sheaths, 800 g m(-2), was found at a depth of 90 m......The filamentous sulfur bacteria Thioploca spp, produce dense bacterial mats in the shelf area off the coast of Chile and Peru. The mat consists of common sheaths, shared by many filaments, that reach 5 to 10 cm dean into the sediment, The structure of the Thioploca communities off the Bay...

Application of Spray Foam Insulation Under Plywood and Oriented Strand Board Roof Sheathing

Energy Technology Data Exchange (ETDEWEB)

Grin, A. [Building Science Corporation, Somerville, MA (United States); Smegal, J. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

2013-10-01

Unvented roof strategies with open cell and closed cell spray polyurethane foam insulation sprayed to the underside of roof sheathing have been used since the mid-1990's to provide durable and efficient building enclosures. However, there have been isolated moisture related incidents reported anecdotally that raise potential concerns about the overall hygrothermal performance of these systems. This project involved hygrothermal modeling of a range of rainwater leakage and field evaluations of in-service residential roofs using spray foam insulation. All of the roof assemblies modeled exhibited drying capacity to handle minor rainwater leakage. All field evaluation locations of in-service residential roofs had moisture contents well within the safe range for wood-based sheathing. Explorations of eleven in-service roof systems were completed. The exploration involved taking a sample of spray foam from the underside of the roof sheathing, exposing the sheathing, then taking a moisture content reading. All locations had moisture contents well within the safe range for wood-based sheathing. One full-roof failure was reviewed, as an industry partner was involved with replacing structurally failed roof sheathing. In this case the manufacturer's investigation report concluded that the spray foam was installed on wet OSB based on the observation that the spray foam did not adhere well to the substrate and the pore structure of the closed cell spray foam at the ccSPF/OSB interface was indicative of a wet substrate.

Modelling of the dual frequency capacitive sheath in the intermediate pressure range

International Nuclear Information System (INIS)

Boyle, P C; Robiche, J; Turner, M M

2004-01-01

The nonlinearity of the plasma sheath in dual frequency capacitively coupled reactors is investigated for frequencies well above the ion plasma frequency. This work focuses on the behaviour of the voltage and the sheath width with respect to the driving current source and the collisionality regime. For typical plasma processing applications, the gas pressure ranges from a few milliTorrs to hundreds of milliTorrs, and the ion dynamics span different collisional regimes. To describe these different ion dynamics, we have used a collisionless model and a variable mobility model. The sheath widths and the voltages obtained from these two models have then been compared

Functional Loss of Bmsei Causes Thermosensitive Epilepsy in Contractile Mutant Silkworm, Bombyx mori

Science.gov (United States)

Nie, Hongyi; Cheng, Tingcai; Huang, Xiaofeng; Zhou, Mengting; Zhang, Yinxia; Dai, Fangyin; Mita, Kazuei; Xia, Qingyou; Liu, Chun

2015-07-01

The thermoprotective mechanisms of insects remain largely unknown. We reported the Bombyx mori contractile (cot) behavioral mutant with thermo-sensitive seizures phenotype. At elevated temperatures, the cot mutant exhibit seizures associated with strong contractions, rolling, vomiting, and a temporary lack of movement. We narrowed a region containing cot to ~268 kb by positional cloning and identified the mutant gene as Bmsei which encoded a potassium channel protein. Bmsei was present in both the cell membrane and cytoplasm in wild-type ganglia but faint in cot. Furthermore, Bmsei was markedly decreased upon high temperature treatment in cot mutant. With the RNAi method and injecting potassium channel blockers, the wild type silkworm was induced the cot phenotype. These results demonstrated that Bmsei was responsible for the cot mutant phenotype and played an important role in thermoprotection in silkworm. Meanwhile, comparative proteomic approach was used to investigate the proteomic differences. The results showed that the protein of Hsp-1 and Tn1 were significantly decreased and increased on protein level in cot mutant after thermo-stimulus, respectively. Our data provide insights into the mechanism of thermoprotection in insect. As cot phenotype closely resembles human epilepsy, cot might be a potential model for the mechanism of epilepsy in future.

Studies of RF sheaths and diagnostics on IShTAR

Energy Technology Data Exchange (ETDEWEB)

Crombé, K., E-mail: Kristel.Crombe@UGent.be [Department of Applied Physics, Ghent University, Ghent (Belgium); LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Devaux, S.; Faudot, E.; Heuraux, S.; Moritz, J. [YIJL, UMR7198 CNRS-Université de Lorraine, Nancy (France); D’Inca, R.; Faugel, H.; Fünfgelder, H.; Jacquot, J.; Ochoukov, R. [Max-Planck-Institut für Plasmaphysik, Garching (Germany); Louche, F.; Tripsky, M.; Van Eester, D.; Wauters, T. [LPP-ERM/KMS, Royal Military Academy, Brussels (Belgium); Noterdaeme, J.-M. [Department of Applied Physics, Ghent University, Ghent (Belgium); Max-Planck-Institut für Plasmaphysik, Garching (Germany)

2015-12-10

IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed to excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RF antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.

Azospirillum brasilense and Azospirillum lipoferum Hydrolyze Conjugates of GA20 and Metabolize the Resultant Aglycones to GA1 in Seedlings of Rice Dwarf Mutants1

Science.gov (United States)

Cassán, Fabricio; Bottini, Rubén; Schneider, Gernot; Piccoli, Patricia

2001-01-01

Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones, including gibberellins (GAs). In this work, Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice (Oryza sativa) mutants, dy and dx, when the inoculated seedlings were supplied with [17,17-2H2]GA20-glucosyl ester or [17,17- 2H2]GA20-glucosyl ether. Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17-2H2]GA20 and its subsequent 3β-hydroxylation to [17,17-2H2]GA1 by the microorganism for the dy mutant, and by both the rice plant and microorganism for the dx mutant. PMID:11299384

Use of a hot sheath Tormac for advance fuels

International Nuclear Information System (INIS)

Levine, M.A.

1977-01-01

The use of hot electrons in a Tormac sheath is predicted to improve stability and increase ntau by an order of magnitude. An effective ntau for energy containment is derived and system parameters for several advance fuels are shown. In none of the advance fuels cases considered is a reactor with fields greater than 10 Wb or major plasma radius of more than 3 m required for ignition. Minimum systems have power output of under 100 MW thermal. System parameters for a hot sheath Tormac have a wide latitude. Sizes, magnetic fields, operating temperatures can be chosen to optimize engineering and economic considerations

Stress/strain characteristics of Cu alloy sheath in situ processed MgB2 superconducting wires

International Nuclear Information System (INIS)

Katagiri, Kazumune; Kasaba, Koichi; Shoji, Yoshitaka

2005-01-01

The mechanical properties of copper and copper alloy (Cu-Zr, Cu-Be and Cu-Cr) sheath in situ PIT-processed MgB 2 superconducting wires were studied at room temperature (RT) and 4.2 K. The effects of stress-strain on the critical current (I c ) of the wires have also been studied at 4.2 K and in magnetic fields up to 5 T. It has been clarified that alloying the Cu sheath significantly increases the yield and flow stresses of the wires at both RT and 4.2 K. The 0.5% flow stresses of the Cu alloy sheath wire were 147-237 MPa, whereas that of Cu was 55 MPa. At RT, serration corresponding to multiple cracking was observed around a strain of 0.4% and the stress-strain curves saturated beyond that point. The strain dependence of I c prior to the critical strain (ε irr ) was different depending on the magnetic field; being almost constant at 2 T and increasing with strain at 5 T. The I c decreased beyond ε irr , which is much larger for Cu alloy sheath wires as compared to Cu sheath wire. This is due to the difference in the residual compressive strain in the MgB 2 core during cooling from the heat-treatment temperature to 4.2 K, which is determined through relaxation by yielding in the sheath materials. The transverse compression tests revealed that the I c of the Cu alloy sheath wire did not degrade up to 314 MPa, which is also higher than that of Cu sheath wire. (author)

Synthesis of sheath voltage drops in asymmetric radio-frequency discharges

International Nuclear Information System (INIS)

Yonemura, Shigeru; Nanbu, Kenichi; Iwata, Naoaki

2004-01-01

A sheath voltage drop in asymmetric discharges is one of the most important parameters of radio-frequency capacitively coupled plasmas because it determines the kinetic energy of the ions incident on the target or substrate. In this study, we developed a numerical simulation code to estimate the sheath voltage drops and, consequently, the self-bias voltage. We roughly approximated general asymmetric rf discharges to one-dimensional spherical ones. The results obtained by using our simulation code are consistent with measurements and Lieberman's theory

Effect of composition on the fabrication and properties of Ag-Cu alloy sheathed (Bi,Pb)2223 tapes

International Nuclear Information System (INIS)

Nakamura, Yuichi; Nakashima, Sohei; Inada, Ryoji; Oota, Akio

2004-01-01

To achieve high J c values as well as high mechanical strength, the effects of Ag-Cu alloy sheath and initial composition of precursor on the microstructure and J c properties of Ag-Cu alloy sheathed tapes were investigated. The alkaline-earth cuprate particles were found to form preferentially near the interface between superconducting core and sheath. Although the worse (Bi,Pb)2223 purity and microstructure of alloy sheathed tapes, the reduction of J c values of the tapes was small especially in 7-filaments tapes. This might be explained by the well grain alignment of (Bi,Pb)2223 into the middle region of the filament due to the high strength of alloy sheath. The usage of the Cu deficient composition was effective to reduce the total amount of 14:24 particle while the filament thickness should be thin to maintain J c values for Ag-Cu alloy sheathed tapes due to the lack of Cu diffusion from the sheath to convert 2212 into (Bi,Pb) in the middle region of the filament

On the biogenesis of the myelin sheath : Cognate polarized trafficking pathways in oligodendrocytes

NARCIS (Netherlands)

de Vries, H; Hoekstra, D

2000-01-01

Oligodendrocytes, the myelinating cells of the central nervous system, are capable of transporting vast quantities of proteins and of lipids, In particular galactosphingolipids, to the myelin sheath. The sheath is continuous with the plasma membrane of the oligodendrocyte, but the composition of

Effects of Fast-Ion Injection on a Magnetized Sheath near a Floating Wall

International Nuclear Information System (INIS)

Li Jiajia; Hu Zhanghu; Song Yuanhong; Wang Younian

2013-01-01

A fully kinetic particle-in-cell/Monte Carlo model is employed to self-consistently study the effects of fast-ion injection on sheath potential and electric field profile in collisional magnetized plasma with a floating absorbing wall. The influences of the fast-ion injection velocity and density, the magnetic field and angle θ 0 formed by the magnetic field and the x-axis on the sheath potential and electric field are discussed in detail. Numerical results show that increasing fast-ion injection density or decreasing injection velocity can enhance the potential drop and electric field in the sheath. Also, increasing the magnetic field strength can weaken the loss of charged particles to the wall and thus decrease the potential and electric field in the sheath. The time evolution of ion flux and velocity distribution on the wall is found to be significantly affected by the magnetic field.

Effects of Reentry Plasma Sheath on Mutual-Coupling Property of Array Antenna

Directory of Open Access Journals (Sweden)

B. W. Bai

2015-01-01

Full Text Available A plasma sheath enveloping a reentry vehicle would cause the failure of on-board antennas, which is an important effect that contributes to the “blackout” problem. The method of replacing the on-board single antenna with the array antennas and using beamforming technology has been proposed to mitigate “blackout” problem by many other researchers. Because the plasma sheath is a reflective medium, plasma will alter the mutual coupling between array elements and degrade the beamforming performance of array antenna. In this paper, the effects of the plasma sheath on the mutual coupling properties between adjacent array elements are studied utilizing the algorithm of finite integration technique. Results show that mutual coupling coefficients of array elements are deteriorating more seriously with the decrease of collision frequency. Moreover, when electron density and collision frequency are both large, plasma sheath improves the mutual coupling property of array elements; this conclusion suggests that replacing the on-board single antenna with the array antennas and using beamforming technology can be adopted to mitigate the blackout problem in this condition.

CT saber-sheath trachea. Correlation with clinical, chest radiographic and functional findings

International Nuclear Information System (INIS)

Trigaux, J.P.; Hermes, G.; Dubois, P.; Beers, B. van; Delaunois, L.; Jamart, J.

1994-01-01

The diagnosis of saber-sheath trachea is easy at CT due to its cross-sectional imaging, but the significance of this CT sign has not been evaluated in the diagnosis of chronic obstructive pulmonary disease (COPD). Various signs of COPD were compared between a series of 20 patients with a saber-sheath trachea at CT (tracheal index ≤66%) and a group of 20 pneumologic control patients without saber-sheath trachea (tracheal index ≥70%). These signs include clinical and standard radiographic indices of COPD, sternum-spine distance and 3 functional tests of COPD: forced expiratory volume in one second, carbon monoxide diffusing lung capacity, and funtional residual capacity (FRC). A significant difference was found between the 2 groups, concerning the values of FRC and of sternum-spine distance (p -2 ). The tracheal index was significantly correlated with the FRC values and with the sternum-spine distance. No other significant difference was observed. It is concluded that saber-sheath trachea is basically a sign of hyperinflation. (orig./MG)

A novel flagellar sheath protein, FcpA, determines filament coiling, translational motility and virulence for the Leptospira spirochete.

Science.gov (United States)

Wunder, Elsio A; Figueira, Cláudio P; Benaroudj, Nadia; Hu, Bo; Tong, Brian A; Trajtenberg, Felipe; Liu, Jun; Reis, Mitermayer G; Charon, Nyles W; Buschiazzo, Alejandro; Picardeau, Mathieu; Ko, Albert I

2016-08-01

Leptospira are unique among bacteria based on their helical cell morphology with hook-shaped ends and the presence of periplasmic flagella (PF) with pronounced spontaneous supercoiling. The factors that provoke such supercoiling, as well as the role that PF coiling plays in generating the characteristic hook-end cell morphology and motility, have not been elucidated. We have now identified an abundant protein from the pathogen L. interrogans, exposed on the PF surface, and named it Flagellar-coiling protein A (FcpA). The gene encoding FcpA is highly conserved among Leptospira and was not found in other bacteria. fcpA(-) mutants, obtained from clinical isolates or by allelic exchange, had relatively straight, smaller-diameter PF, and were not able to produce translational motility. These mutants lost their ability to cause disease in the standard hamster model of leptospirosis. Complementation of fcpA restored the wild-type morphology, motility and virulence phenotypes. In summary, we identified a novel Leptospira 36-kDa protein, the main component of the spirochete's PF sheath, and a key determinant of the flagella's coiled structure. FcpA is essential for bacterial translational motility and to enable the spirochete to penetrate the host, traverse tissue barriers, disseminate to cause systemic infection and reach target organs. © 2016 John Wiley & Sons Ltd.

Core-Sheath Paraffin-Wax-Loaded Nanofibers by Electrospinning for Heat Storage.

Science.gov (United States)

Lu, Yuan; Xiao, Xiudi; Zhan, Yongjun; Huan, Changmeng; Qi, Shuai; Cheng, Haoliang; Xu, Gang

2018-04-18

Paraffin wax (PW) is widely used for smart thermoregulation materials due to its good thermal performance. However, the leakage and low thermal conductivity of PW hinder its application in the heat storage field. Accordingly, developing effective methods to address these issues is of great importance. In this study, we explored a facile approach to obtain PW-loaded core-sheath structured flexible nanofibers films via coaxial electrospinning technique. The PW as the core layer was successfully encapsulated by the sheath-layer poly(methyl methacrylate). The diameter of the fiber core increased from 395 to 848 nm as the core solution speed rate increased from 0.1 to 0.5 mL/h. In addition, it can be seen that higher core solution speed rate could lead to higher PW encapsulation efficiency according to the transmission electron microscopy results. The core-sheath nanofiber films, moreover, possessed the highest latent heat of 58.25 J/g and solidifying enthalpy of -56.49 J/g. In addition, we found that after 200 thermal cycles, there was little change in latent heat, which demonstrated that it is beneficial for the PW-loaded core-sheath structure to overcome the leakage issue and enhance thermal stability properties for the thermoregulation film.

Physical models for the description of an electrodynamically accelerated plasma sheath

International Nuclear Information System (INIS)

Zambreanu, V.

1977-01-01

An analysis of the models proposed for the description of the plasma sheath dynamics in a coaxial system (of the same type as that operating at the Bucharest Institute of Physics) is presented. A particular attention is paid to the physical structure of the accelerated plasma. It has been shown that a self-consistent model could be derived from a phenomenological description of the sheath structure. The physical models presented so far in the literature have been classified into three groups: the hydrodynamic models, the plasma sheet models and the shock wave models. Each of these models is briefly described. The simplifying assumptions used in the construction of these models have been pointed out. The final conclusion has been that, under these assumptions, none of these models taken separately could completely and correctly describe the dynamical state of the plasma sheath. (author)

Measurements of the sheath potential in low density plasmas

International Nuclear Information System (INIS)

Bradley, J.W.; Khamis, R.A.; Sanduk, M.I.; Elliott, J.A.; Rusbridge, M.G.

1992-01-01

We have measured the sheath potential around a probe in a range of different plasma conditions in the UMIST, University of Manchester Institute of Science and Technology, quadrupole GOLUX and in a related experiment in which the plasma expands freely to supersonic velocity. In the latter case, the sheath potential agrees well with an appropriately modified form of the usual expression for a field-free plasma, for both hydrogen and argon plasmas. In GOLUX, however, the sheath potential is found to be significantly less than the accepted value, even when the magnetic field is taken into account. For the slow moving plasma in the outer part of the quadrupole confining field, we present both theoretical and experimental results showing that the reduction is due to truncation of the electron velocity distribution as the probe drains electrons from a closed flux tube faster than they can be replaced. In the central hot plasma, however, this explanation cannot apply. Here, the plasma is moving at about sonic speed and magnetic effects are weak. Nevertheless, the results are significantly different from both in the field free experiment. (author)

Double polymer sheathed carbon nanotube supercapacitors show enhanced cycling stability

Science.gov (United States)

Zhao, Wenqi; Wang, Shanshan; Wang, Chunhui; Wu, Shiting; Xu, Wenjing; Zou, Mingchu; Ouyang, An; Cao, Anyuan; Li, Yibin

2015-12-01

Pseudo-materials are effective in boosting the specific capacitance of supercapacitors, but during service their degradation may also be very strong, causing reduced cycling stability. Here, we show that a carbon nanotube sponge grafted by two conventional pseudo-polymer layers in sequence can serve as a porous supercapacitor electrode with significantly enhanced cycling stability compared with single polymer grafting. Creating conformal polymer coatings on the nanotube surface and the resulting double-sheath configuration are important structural factors leading to the enhanced performance. Combining different polymers as double sheaths as reported here might be a potential route to circumvent the dilemma of pseudo-materials, and to simultaneously improve the capacitance and stability for various energy storage devices.Pseudo-materials are effective in boosting the specific capacitance of supercapacitors, but during service their degradation may also be very strong, causing reduced cycling stability. Here, we show that a carbon nanotube sponge grafted by two conventional pseudo-polymer layers in sequence can serve as a porous supercapacitor electrode with significantly enhanced cycling stability compared with single polymer grafting. Creating conformal polymer coatings on the nanotube surface and the resulting double-sheath configuration are important structural factors leading to the enhanced performance. Combining different polymers as double sheaths as reported here might be a potential route to circumvent the dilemma of pseudo-materials, and to simultaneously improve the capacitance and stability for various energy storage devices. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05978j

Sheath and arc-column voltages in high-pressure arc discharges

International Nuclear Information System (INIS)

Benilov, M S; Benilova, L G; Li Heping; Wu Guiqing

2012-01-01

Electrical characteristics of a 1 cm-long free-burning atmospheric-pressure argon arc are calculated by means of a model taking into account the existence of a near-cathode space-charge sheath and the discrepancy between the electron and heavy-particle temperatures in the arc column. The computed arc voltage exhibits a variation with the arc current I similar to the one revealed by the experiment and exceeds experimental values by no more than approximately 2 V in the current range 20-175 A. The sheath contributes about two-thirds or more of the arc voltage. The LTE model predicts a different variation of the arc voltage with I and underestimates the experimental values appreciably for low currents but by no more than approximately 2 V for I ≳ 120 A. However, the latter can hardly be considered as a proof of unimportance of the space-charge sheath at high currents: the LTE model overestimates both the resistance of the bulk of the arc column and the resistance of the part of the column that is adjacent to the cathode, and this overestimation to a certain extent compensates for the neglect of the voltage drop in the sheath. Furthermore, if the latter resistance were evaluated in the framework of the LTE model in an accurate way, then the overestimation would be still much stronger and the obtained voltage would significantly exceed those observed in the experiment.

Dengue fever with rectus sheath hematoma: A case report

Directory of Open Access Journals (Sweden)

Anurag Sharma

2014-01-01

Full Text Available Dengue fever, also known as breakbone fever, is an infectious tropical disease caused by the Dengue virus. It is associated with a number of complications, which are well documented. However, Dengue fever associated with rectus sheath hematoma (RSH is a very rare complication. Only one case report has been published prior supporting the association of Dengue fever with RSH. We report a case of Dengue fever who presented with RSH and was successfully treated conservatively. RSH is also an uncommon cause of acute abdominal pain. It is accumulation of blood in the sheath of the rectus abdominis, secondary to rupture of an epigastric vessel or muscle tear.

Evaluation of the equine digital flexor tendon sheath using diagnostic ultrasound and contrast radiography

International Nuclear Information System (INIS)

Redding, W.R.

1994-01-01

This study was designed to evaluate the normal anatomy of the digital flexor tendon sheath using contrast radiography and diagnostic ultrasound. Iodinated contrast medium was injected into eight cadaver limbs and the limbs immediately frozen. Lateromedial and dorsopalmar/plantar radiographs were made. These limps were then cut transversely and proximal to distal radiographs of each slab were made. This cross sectional contrast methodology allowed the visualization of the relative size and shape of the superficial and deep digital flexor tendons as well as the potential space taken by effusions of the digital flexor tendon sheath. The second part of the study used twelve live animals with normal digital flexor tendon sheaths. Ultrasonographic measurement of the structures of the digital flexor tendon sheath at each level were compiled. This documented the ability of diagnostic ultrasound to image: 1) the superficial and deep digital flexor tendons, 2) the proximal and distal ring of the manica flexoria, 3) the straight and oblique sesamoidean ligaments, and 4) the mesotendinous attachments to the superficial and deep flexor tendons. Iodinated contrast medium was then injected into the digital flexor tendon sheath and the ultrasonography repeated. These images were compared with those obtained from contrast radiography and prosections of twenty normal limbs. The iodinated contrast medium enhanced sonographic imaging of the structures of the digital tendon sheath, particularly the abaxial borders of the superficial digital flexor tendon branches and the mesotendinous attachments to the superficial and deep digital flexor tendons

ELESTRES: performance of nuclear fuel, circumferential ridging, and multiaxial elastic-plastic stresses in sheaths

International Nuclear Information System (INIS)

Tayal, M.

1986-10-01

The finite element code ELESTRES models the two-dimensional axisymmetric behaviour of a CANDU fuel element during normal operation. The main focus of the code is to estimate temperatures, fission gas release, and axial variations of deformation/stresses in the pellet and in the sheath. Thus the code is able to predict details like stresses/strains at circumferential ridges. This paper describes the current version of ELESTRES. The emphasis is on a recent addition: multiaxial stresses in the sheath near circumferential ridges. For accuracy in the critical region, a fine mesh is used near the ridge. To keep computing costs low, a coarse mesh is used near the midplane of the pellet. Predictions of ELESTRES show good agreement with abouth 80 measurements of fission-gas-release. In this paper, we also present ELESTRES predictions of hoop strains in sheaths, for two irradiations: element ABS and bundle GB. For both irradiations, predictions, compare favourably with measurements. An illustrative example shows that near circumferential ridges, bending contributes to multiaxial stresses in the sheath. This can have a significant effect on sheath integrity, such as during stress-corrosion-cracking due to power-increases, or during corrosion-assisted-fatigue due to power cycling

Redefinition of the self-bias voltage in a dielectrically shielded thin sheath RF discharge

Science.gov (United States)

Ho, Teck Seng; Charles, Christine; Boswell, Rod

2018-05-01

In a geometrically asymmetric capacitively coupled discharge where the powered electrode is shielded from the plasma by a layer of dielectric material, the self-bias manifests as a nonuniform negative charging in the dielectric rather than on the blocking capacitor. In the thin sheath regime where the ion transit time across the powered sheath is on the order of or less than the Radiofrequency (RF) period, the plasma potential is observed to respond asymmetrically to extraneous impedances in the RF circuit. Consequently, the RF waveform on the plasma-facing surface of the dielectric is unknown, and the behaviour of the powered sheath is not easily predictable. Sheath circuit models become inadequate for describing this class of discharges, and a comprehensive fluid, electrical, and plasma numerical model is employed to accurately quantify this behaviour. The traditional definition of the self-bias voltage as the mean of the RF waveform is shown to be erroneous in this regime. Instead, using the maxima of the RF waveform provides a more rigorous definition given its correlation with the ion dynamics in the powered sheath. This is supported by a RF circuit model derived from the computational fluid dynamics and plasma simulations.

The role of the sheath in magnetized plasma turbulence and flows

International Nuclear Information System (INIS)

Loizu, J.

2013-01-01

Controlled nuclear fusion could provide our society with a clean, safe, and virtually inexhaustible source of electric power production. The tokamak has proven to be capable of producing large amounts of fusion reactions by conning magnetically the fusion fuel at sufficiently high density and temperature, thus in the plasma state. Because of turbulence, however, high temperature plasma reaches the outermost region of the tokamak, the Scrape-Off Layer (SOL), which features open magnetic field lines that channel particles and heat into a dedicated region of the vacuum vessel. The plasma dynamics in the SOL is crucial in determining the performance of tokamak devices, and constitutes one of the greatest uncertainties in the success of the fusion program. In the last few years, the development of numerical codes based on reduced fluid models has provided a tool to study turbulence in open field line configurations. In particular, the GBS (Global Braginskii Solver) code has been developed at CRPP and is used to perform global, three-dimensional, full-n, flux-driven simulations of plasma turbulence in open field lines. Reaching predictive capabilities is an outstanding challenge that involves a proper treatment of the plasma-wall interactions at the end of the field lines, to well describe the particle and energy losses. This involves the study of plasma sheaths, namely the layers forming at the interface between plasmas and solid surfaces, where the drift and quasi neutrality approximations break down. This is an investigation of general interest, as sheaths are present in all laboratory plasmas. This thesis presents progress in the understanding of plasma sheaths and their coupling with the turbulence in the main plasma. A kinetic code is developed to study the magnetized plasma-wall transition region and derive a complete set of analytical boundary conditions that supply the sheath physics to fluid codes. These boundary conditions are implemented in the GBS code and

Sheath formation of a plasma containing multiply charged ions, cold and hot electrons, and emitted electrons

International Nuclear Information System (INIS)

You, H.J.

2012-01-01

It is quite well known that ion confinement is an important factor in an electron cyclotron resonance ion source (ECRIS) as it is closely related to the plasma potential. A model of sheath formation was extended to a plasma containing multiply charged ions (MCIs), cold and hot electrons, and secondary electrons emitted either by MCIs or hot electrons. In the model, a modification of the 'Bohm criterion' was given, the sheath potential drop and the critical emission condition were also analyzed. It appears that the presence of hot electrons and emitted electrons strongly affects the sheath formation so that smaller hot electrons and larger emission current result in reduced sheath potential (or floating potential). However the sheath potential was found to become independent of the emission current J when J > J c , (where J c is the critical emission current. The paper is followed by the associated poster

Sheath structure in negative ion sources for fusion (invited)

International Nuclear Information System (INIS)

McAdams, R.; King, D. B.; Surrey, E.; Holmes, A. J. T.

2012-01-01

In fusion negative ion sources, the negative ions are formed on the caesiated plasma grid predominantly by hydrogen atoms from the plasma. The space charge of the negative ions leaving the wall is not fully compensated by incoming positive ions and at high enough emission a virtual cathode is formed. This virtual cathode limits the flux of negative ions transported across the sheath to the plasma. A 1D collisionless model of the sheath is presented taking into account the virtual cathode. The model will be applied to examples of the ion source operation. Extension of the model to the bulk plasma shows good agreement with experimental data. A possible role for fast ions is discussed.

Development of Plant Mutant Resources with an useful characters by Radiation Fusion Technology

International Nuclear Information System (INIS)

Kang, Si Yong; Kim, Dong Sub; Lee, Geung Joo

2009-02-01

A mutation breeding is to use physical or chemical mutagens to induce mutagenesis, followed by individual selections with favorable traits. The mutation breeding has many advantages over other breeding methods, which include the usefulness for improving one or two inferior characteristics, applications to broad species with different reproductive systems or to diverse plant materials, native or plant introduction with narrow genetic background, time and cost-effectiveness, and valuable mutant resources for genomics researches. Recent applications of the radiation breeding techniques to developments of flowering plants or food crops with improved functional constituents heightened the public's interests in agriculture and in our genetic resources and seed industries. The goals of this project, therefore, include achieving advances in domestic seed industries and agricultural productivities by developing and using new radiation mutants with favored traits, protecting an intellectual property right of domestic seeds or germplasms, and sharing the valuable mutants and mutated gene information for the genomics and biotech researches that eventually leads to economic benefits

Magnetic sheath effect on the gross and net erosion rates due to impurities

Science.gov (United States)

Mellet, N.; Pégourié, B.; Martin, C.; Gunn, J. P.; Bufferand, H.; Roubin, P.

2016-02-01

Simulations of impurity trajectories in deuterium plasmas in the vicinity of the surface are performed by taking into account the magnetic sheath in conditions relevant for ITER and WEST. We show that the magnetic sheath has a strong effect on the average impact angle of impurities in divertor conditions and that it can lead to an increase of ≈ 60% at the gross erosion maximum for neon (Ne+4) compared to the case when only the cyclotron motion is considered. The evaluation of the net erosion has been undertaken by retaining local redeposition of tungsten (W). We investigate how it is affected by the sheath magnetic potential profile. The largest effect is however observed when an energy distribution is considered. In this case the number of particles that manage to exit the sheath is larger as it is dominated by the more energetic particles. The comparison with other work is also discussed. The application to a scenario of the WEST project is finally performed, which exhibits a moderate, however non negligible, erosion of the plasma facing components.

A smart core-sheath nanofiber that captures and releases red blood cells from the blood

Science.gov (United States)

Shi, Q.; Hou, J.; Zhao, C.; Xin, Z.; Jin, J.; Li, C.; Wong, S.-C.; Yin, J.

2016-01-01

A smart core-sheath nanofiber for non-adherent cell capture and release is demonstrated. The nanofibers are fabricated by single-spinneret electrospinning of poly(N-isopropylacrylamide) (PNIPAAm), polycaprolactone (PCL) and nattokinase (NK) solution blends. The self-assembly of PNIPAAm and PCL blends during the electrospinning generates the core-sheath PCL/PNIPAAm nanofibers with PNIPAAm as the sheath. The PNIPAAm-based core-sheath nanofibers are switchable between hydrophobicity and hydrophilicity with temperature change and enhance stability in the blood. When the nanofibers come in contact with blood, the NK is released from the nanofibers to resist platelet adhesion on the nanofiber surface, facilitating the direct capture and isolation of red blood cells (RBCs) from the blood above phase-transition temperature of PNIPAAm. Meanwhile, the captured RBCs are readily released from the nanofibers with temperature stimuli in an undamaged manner. The release efficiency of up to 100% is obtained while maintaining cellular integrity and function. This work presents promising nanofibers to effectively capture non-adherent cells and release for subsequent molecular analysis and diagnosis of single cells.A smart core-sheath nanofiber for non-adherent cell capture and release is demonstrated. The nanofibers are fabricated by single-spinneret electrospinning of poly(N-isopropylacrylamide) (PNIPAAm), polycaprolactone (PCL) and nattokinase (NK) solution blends. The self-assembly of PNIPAAm and PCL blends during the electrospinning generates the core-sheath PCL/PNIPAAm nanofibers with PNIPAAm as the sheath. The PNIPAAm-based core-sheath nanofibers are switchable between hydrophobicity and hydrophilicity with temperature change and enhance stability in the blood. When the nanofibers come in contact with blood, the NK is released from the nanofibers to resist platelet adhesion on the nanofiber surface, facilitating the direct capture and isolation of red blood cells (RBCs) from

Sheath-lens probe for negative ion detection in reactive plasmas

International Nuclear Information System (INIS)

Stamate, E.; Sugai, H.; Takai, O.; Ohe, K.

2004-01-01

A method that allows easy and inexpensive detection of negative ions is introduced. The method is based upon the electrostatic lens effect of the sheath layer evolving to a positively biased planar probe that focuses the negative charges to distinct regions on the surface. Trajectories of negative ions inside the sheath are obtained after computing the potential and electric field distribution by solving in three dimensions the nonlinear Poisson equation. The negative ions' flux to square and disk probes is developed in Ar/SF 6 and O 2 plasmas. The method allows negative ion detection with sensitivity higher than that of Langmuir probes

Characterization of a Thermo-Inducible Chlorophyll-Deficient Mutant in Barley

Directory of Open Access Journals (Sweden)

Rong Wang

2017-11-01

Full Text Available Leaf color is an important trait for not only controlling crop yield but also monitoring plant status under temperature stress. In this study, a thermo-inducible chlorophyll-deficient mutant, named V-V-Y, was identified from a gamma-radiated population of the barley variety Vlamingh. The leaves of the mutant were green under normal growing temperature but turned yellowish under high temperature in the glasshouse experiment. The ratio of chlorophyll a and chlorophyll b in the mutant declined much faster in the first 7–9 days under heat treatment. The leaves of V-V-Y turned yellowish but took longer to senesce under heat stress in the field experiment. Genetic analysis indicated that a single nuclear gene controlled the mutant trait. The mutant gene (vvy was mapped to the long arm of chromosome 4H between SNP markers 1_0269 and 1_1531 with a genetic distance of 2.2 cM and a physical interval of 9.85 Mb. A QTL for grain yield was mapped to the same interval and explained 10.4% of the yield variation with a LOD score of 4. This QTL is coincident with the vvy gene interval that is responsible for the thermo-inducible chlorophyll-deficient trait. Fine mapping, based on the barley reference genome sequence, further narrowed the vvy gene to a physical interval of 0.428 Mb with 11 annotated genes. This is the first report of fine mapping a thermo-inducible chlorophyll-deficient gene in barley.

Contribution to the physical study of sheath failure detections

International Nuclear Information System (INIS)

Mangin, Jean-Paul

1968-11-01

As the study of an installation aimed at the detection of sheath failure requires the knowledge of a great number of data related to all the fields of nuclear technology (fission mechanisms, sheath failure mechanisms, recoil of fission products, distribution of the heat transfer fluid in the reactor, techniques of measurement of beta and gamma neutrons, nuclear safety, and so on), this report aims at highlighting some specific issues, more particularly those related to sensors based on delayed neutrons. After having recalled the principles of sheath failure detection, the author presents the various aspects of the study of the formation of fission products and of their passage into the heat transfer fluid: detection by using delayed neutrons, detection by electrostatic collection, passage of fuel fission products into the coolant (recoil, corrosion, gaseous diffusion in the fuel), formation of fission products in the fuel (fission product efficiency). He reports the study of the transport of fission products by the coolant from their place of birth to the place of measurement. He presents the system of measurement by detection of delayed neutrons and by electrostatic collection, reports a sensitivity calculation, a background noise assessment, the determination of detection threshold, and the application of sensitivity and detection thresholds calculations [fr

An integrative time-varying frequency detection and channel sounding method for dynamic plasma sheath

Science.gov (United States)

Shi, Lei; Yao, Bo; Zhao, Lei; Liu, Xiaotong; Yang, Min; Liu, Yanming

2018-01-01

The plasma sheath-surrounded hypersonic vehicle is a dynamic and time-varying medium and it is almost impossible to calculate time-varying physical parameters directly. The in-fight detection of the time-varying degree is important to understand the dynamic nature of the physical parameters and their effect on re-entry communication. In this paper, a constant envelope zero autocorrelation (CAZAC) sequence based on time-varying frequency detection and channel sounding method is proposed to detect the plasma sheath electronic density time-varying property and wireless channel characteristic. The proposed method utilizes the CAZAC sequence, which has excellent autocorrelation and spread gain characteristics, to realize dynamic time-varying detection/channel sounding under low signal-to-noise ratio in the plasma sheath environment. Theoretical simulation under a typical time-varying radio channel shows that the proposed method is capable of detecting time-variation frequency up to 200 kHz and can trace the channel amplitude and phase in the time domain well under -10 dB. Experimental results conducted in the RF modulation discharge plasma device verified the time variation detection ability in practical dynamic plasma sheath. Meanwhile, nonlinear phenomenon of dynamic plasma sheath on communication signal is observed thorough channel sounding result.

Tunneled dialysis catheter exchange with fibrin sheath disruption is not associated with increased rate of bacteremia.

Science.gov (United States)

Valliant, Amanda M; Chaudhry, Muhammad K; Yevzlin, Alexander S; Astor, Brad; Chan, Micah R

2015-01-01

Tunneled dialysis catheters are the most common form of vascular access among incident dialysis patients in the United States. Fibrin sheath formation is a frequent cause of late catheter dysfunction requiring an exchange procedure with balloon disruption of the fibrin sheath. It is unknown whether fibrin sheath disruption is associated with increased incidence of bacteremia or catheter failure. We reviewed all tunneled dialysis catheter exchange procedures at the University of Wisconsin between January 2008 and December 2011. The primary outcome was incidence of bacteremia, defined as positive blood cultures within 2 weeks of the procedure. Catheter failure, requiring intervention or replacement, was examined as a secondary outcome. Baseline characteristics examined included diabetic status, gender, race and age. A total of 163 procedures were reviewed; 67 (41.1%) had fibrin sheath disruption and 96 did not. Bacteremia occurred in 4.5% (3/67) of those with and 3.1% (3/97) of those without fibrin sheath disruption (p=0.65). Fibrin sheath disruption was not significantly associated with the risk of catheter failure (adjusted hazard ratio [aHR]=1.34; 95% confidence interval [CI]: 0.87-2.10; p=0.18). Diabetes was associated with greater risk of catheter failure (aHR=1.88; 95% CI: 1.19-2.95; p=0.006), whereas higher age was associated with a lower risk of catheter failure (aHR per 10 years=0.83; 95% CI: 0.72-0.96; p=0.01). This study demonstrates that there is no significant increase in bacteremia and subsequent catheter dysfunction rates after fibrin sheath disruption compared to simple over the wire exchange. These results are encouraging given the large numbers of patients utilizing tunneled catheters for initial hemodialysis access and the known rates of fibrin sheath formation leading to catheter failure.

The effect of oxygen on the failure of reactor fuel sheaths during a postulated loss-of-coolant accident

International Nuclear Information System (INIS)

Ferner, J.; Rosinger, H.E.

1983-09-01

The failure model for Zircaloy-4 reactor fuel sheaths was used to study the effect of steam oxidation on sheath burst strain. The model, in the form of a computer program called BURST-3, was used to calculate burst strain for a Zircaloy-4 sheath under arbitrary pressure and temperature sequences in an oxidizing (steam) atmosphere. In particular, BURST-3 was used in a parametric study to predict the sheath behaviour in steam as compared to an inert atmosphere, the effect of heating rate, and the effect of circumferential temperature variations on burst strain. It was found that fuel sheath oxidation, which decreases burst strain, becomes increasingly important with increasing temperature and/or time. An effective oxygen concentration of greater than 0.27 wt. percent will cause the sheath to fail with a negligible strain. The hottest region of a sheath will have the highest oxygen concentration, the largest localized strain, and will be the site of failure. The model predictions were compared to experimental data in the range 900 to 1600 K. Agreement between theory and experiment for all three heating rates (5, 25, and 100 K.s -1 ) was very good

Transport of negative ions across a double sheath with a virtual cathode

International Nuclear Information System (INIS)

McAdams, R; King, D B; Surrey, E; Holmes, A J T

2011-01-01

A one-dimensional analytical model of the sheath in a negative ion source, such as those proposed for heating and diagnostic beams on present and future fusion devices, has been developed. The model, which is collisionless, describes the transport of surface produced negative ions from a cathode, across the sheath to a plasma containing electrons, positive ions and negative ions. It accounts for the situation where the emitted flux of negative ions is greater than the space charge limit, where the electric field at the cathode is negative, and a virtual cathode is formed. It is shown that, in the presence of a virtual cathode, there is a maximum current density of negative ions that can be transported across the sheath into the plasma. Furthermore, for high rates of surface production the virtual cathode persists regardless of the negative bias applied to the cathode, so that the current density transported across the sheath is limited. This is a significant observation and implies that present negative ion sources may not be exploiting all of the surface production available. The model is used to calculate the transported negative ion flux in a number of examples. The limitations of the model and proposed future work are also discussed.

FEAST 3.1: finite-element modeling of sheath deformation such as longitudinal ridging and collapse into axial gap

Energy Technology Data Exchange (ETDEWEB)

Wang, X.; Xu, Z.; Kim, Y-S.; Lai, L.; Cheng, G.; Xu, S. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada)

2010-07-01

During normal operation, the collapsible CANDU® fuel sheath deforms, especially, it may deform into longitudinal ridges or collapse instantaneously into the axial gaps between the end pellet and endcap or between two neighbouring pellets. These phenomena occur under certain conditions, such as the coolant pressure exceeding critical pressures for longitudinal ridging or axial collapse. Both longitudinal ridging and axial collapse phenomena result from plastic instability in the sheath under coolant pressure. Longitudinal ridging features one or multiple lobes or 'ridges' (outward from the sheath surface) formed along the sheath in the longitudinal direction. Axial collapse features a 'valley' around the sheath circumference. Both phenomena can lead to sheath overstrain, which in turn potentially leads to sheath failure. The LONGER code, which contains empirical correlations, has been used to predict the critical pressures for these two sheath deformation phenomena. To study fuel behaviour outside of the application ranges of the LONGER empirical correlations, a mechanistic model is needed. FEAST (Finite Element Analysis for Stresses) is an AECL computer code used to assess the structural integrity of the CANDU fuel element. The FEAST code has recently been developed (to Version 3.1) to model processes occurring during longitudinal ridge formation and instantaneous collapse into the axial gap. The new models include those for geometric non-linearity (large deformation, large material rotation), non-linear stress-strain curve for plastic deformation, Zr-4 sheath creep law, and variable Young’s Modulus etc. This paper describes the mechanistic model (FEAST 3.1) development for analyses of longitudinal ridging and instantaneous collapse into axial gap, and the comparison with the results from empirical correlations in LONGER. (author)

FEAST 3.1: finite-element modeling of sheath deformation such as longitudinal ridging and collapse into axial gap

International Nuclear Information System (INIS)

Wang, X.; Xu, Z.; Kim, Y-S.; Lai, L.; Cheng, G.; Xu, S.

2010-01-01

During normal operation, the collapsible CANDU® fuel sheath deforms, especially, it may deform into longitudinal ridges or collapse instantaneously into the axial gaps between the end pellet and endcap or between two neighbouring pellets. These phenomena occur under certain conditions, such as the coolant pressure exceeding critical pressures for longitudinal ridging or axial collapse. Both longitudinal ridging and axial collapse phenomena result from plastic instability in the sheath under coolant pressure. Longitudinal ridging features one or multiple lobes or 'ridges' (outward from the sheath surface) formed along the sheath in the longitudinal direction. Axial collapse features a 'valley' around the sheath circumference. Both phenomena can lead to sheath overstrain, which in turn potentially leads to sheath failure. The LONGER code, which contains empirical correlations, has been used to predict the critical pressures for these two sheath deformation phenomena. To study fuel behaviour outside of the application ranges of the LONGER empirical correlations, a mechanistic model is needed. FEAST (Finite Element Analysis for Stresses) is an AECL computer code used to assess the structural integrity of the CANDU fuel element. The FEAST code has recently been developed (to Version 3.1) to model processes occurring during longitudinal ridge formation and instantaneous collapse into the axial gap. The new models include those for geometric non-linearity (large deformation, large material rotation), non-linear stress-strain curve for plastic deformation, Zr-4 sheath creep law, and variable Young’s Modulus etc. This paper describes the mechanistic model (FEAST 3.1) development for analyses of longitudinal ridging and instantaneous collapse into axial gap, and the comparison with the results from empirical correlations in LONGER. (author)

Magnetically modified sheaths of Leptothrix sp. as an adsorbent for Amido black 10B removal

International Nuclear Information System (INIS)

Angelova, Ralitsa; Baldikova, Eva; Pospiskova, Kristyna; Safarikova, Mirka; Safarik, Ivo

2017-01-01

The goal of this study was to assess the biosorption of Amido black 10B dye from aqueous solutions on magnetically modified sheaths of Leptothrix sp. in a batch system. The magnetic modification of the sheaths was performed using both microwave synthesized iron oxide nano- and microparticles and perchloric acid stabilized ferrofluid. The native and both magnetically modified sheaths were characterized by SEM. Various parameters significantly affecting the adsorption process, such as pH, contact time, temperature and initial concentration, were studied in detail using the adsorbent magnetized by both methods. The highest adsorption efficiency was achieved at pH 2. The maximum adsorption capacities of both types of magnetized material at room temperature were found to be 339.2 and 286.1 mg of dye per 1 g of ferrofluid modified and microwave synthesized particles modified adsorbent, respectively. Thermodynamic study of dye adsorption revealed a spontaneous and endothermic process in the temperature range between 279.15 and 313.15 K. The data were fitted to various equilibrium and kinetic models. Experimental data matched well with the pseudo-second-order kinetics and Freundlich isotherm model. The Leptothrix sheaths have excellent efficacy for dye adsorption. This material can be used as an effective, low-cost adsorbent. - Highlights: • Magnetic modification of Leptothrix sheaths using two methods is proposed. • Such magnetic material is an excellent adsorbent for Amido black 10B. • The magnetically modified sheaths can be easily separated by magnets.

Magnetically modified sheaths of Leptothrix sp. as an adsorbent for Amido black 10B removal

Energy Technology Data Exchange (ETDEWEB)

Angelova, Ralitsa [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Department of General and Industrial Microbiology, Faculty of Biology, Sofia University “St. Kliment Ohridski”, 8 Dragan Tsankov Blvd, 1164 Sofia (Bulgaria); Laboratory Microwave Magnetics, Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd, 1784 Sofia (Bulgaria); Baldikova, Eva [Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Department of Applied Chemistry, Faculty of Agriculture, University of South Bohemia, Branisovska 1457, 370 05 Ceske Budejovice (Czech Republic); Pospiskova, Kristyna [Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 27, 783 71 Olomouc (Czech Republic); Safarikova, Mirka [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Safarik, Ivo, E-mail: ivosaf@yahoo.com [Department of Nanobiotechnology, Biology Centre, ISB, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Global Change Research Institute, CAS, Na Sadkach 7, 370 05 Ceske Budejovice (Czech Republic); Regional Centre of Advanced Technologies and Materials, Palacky University, Slechtitelu 27, 783 71 Olomouc (Czech Republic)

2017-04-01

The goal of this study was to assess the biosorption of Amido black 10B dye from aqueous solutions on magnetically modified sheaths of Leptothrix sp. in a batch system. The magnetic modification of the sheaths was performed using both microwave synthesized iron oxide nano- and microparticles and perchloric acid stabilized ferrofluid. The native and both magnetically modified sheaths were characterized by SEM. Various parameters significantly affecting the adsorption process, such as pH, contact time, temperature and initial concentration, were studied in detail using the adsorbent magnetized by both methods. The highest adsorption efficiency was achieved at pH 2. The maximum adsorption capacities of both types of magnetized material at room temperature were found to be 339.2 and 286.1 mg of dye per 1 g of ferrofluid modified and microwave synthesized particles modified adsorbent, respectively. Thermodynamic study of dye adsorption revealed a spontaneous and endothermic process in the temperature range between 279.15 and 313.15 K. The data were fitted to various equilibrium and kinetic models. Experimental data matched well with the pseudo-second-order kinetics and Freundlich isotherm model. The Leptothrix sheaths have excellent efficacy for dye adsorption. This material can be used as an effective, low-cost adsorbent. - Highlights: • Magnetic modification of Leptothrix sheaths using two methods is proposed. • Such magnetic material is an excellent adsorbent for Amido black 10B. • The magnetically modified sheaths can be easily separated by magnets.

Modeling of Sheath Ion-Molecule Reactions in Plasma Enhanced Chemical Vapor Deposition of Carbon Nanotubes

Science.gov (United States)

Hash, David B.; Govindan, T. R.; Meyyappan, M.

2004-01-01

In many plasma simulations, ion-molecule reactions are modeled using ion energy independent reaction rate coefficients that are taken from low temperature selected-ion flow tube experiments. Only exothermic or nearly thermoneutral reactions are considered. This is appropriate for plasma applications such as high-density plasma sources in which sheaths are collisionless and ion temperatures 111 the bulk p!asma do not deviate significantly from the gas temperature. However, for applications at high pressure and large sheath voltages, this assumption does not hold as the sheaths are collisional and ions gain significant energy in the sheaths from Joule heating. Ion temperatures and thus reaction rates vary significantly across the discharge, and endothermic reactions become important in the sheaths. One such application is plasma enhanced chemical vapor deposition of carbon nanotubes in which dc discharges are struck at pressures between 1-20 Torr with applied voltages in the range of 500-700 V. The present work investigates The importance of the inclusion of ion energy dependent ion-molecule reaction rates and the role of collision induced dissociation in generating radicals from the feedstock used in carbon nanotube growth.

Structural analysis of sheath folds in the Sylacauga Marble Group, Talladega slate belt, southern Appalachians

Science.gov (United States)

Mies, J.W.

1993-01-01

Remnant blocks of marble from the Moretti-Harrah dimension-stone quarry provide excellent exposure of meter-scale sheath folds. Tubular structures with elliptical cross-sections (4 ???Ryz ??? 5) are the most common expression of the folds. The tubes are elongate subparallel to stretching lineation and are defined by centimeter-scale layers of schist. Eccentrically nested elliptical patterns and opposing asymmetry of folds ('S' and 'Z') are consistent with the sheath-fold interpretation. Sheath folds are locally numerous in the Moretti-Harrah quarry but are not widely distributed in the Sylacauga Marble Group; reconnaissance in neighboring quarries provided no additional observations. The presence of sheath folds in part of the Talladega slate belt indicates a local history of plastic, non-coaxial deformation. Such a history of deformation is substantiated by petrographic study of an extracted hinge from the Moretti-Harrah quarry. The sheath folds are modeled as due to passive amplification of initial structures during simple shear, using both analytic geometry and graphic simulation. As indicated by these models, relatively large shear strains (y ??? 9) and longitudinal initial structures are required. The shear strain presumably relates to NW-directed displacement of overlying crystalline rocks during late Paleozoic orogeny. ?? 1993.

Morphological Characterization and Assessment of Genetic Variability, Character Association, and Divergence in Soybean Mutants

Directory of Open Access Journals (Sweden)

M. A. Malek

2014-01-01

Full Text Available Genetic diversity is important for crop improvement. An experiment was conducted during 2011 to study genetic variability, character association, and genetic diversity among 27 soybean mutants and four mother genotypes. Analysis of variance revealed significant differences among the mutants and mothers for nine morphological traits. Eighteen mutants performed superiorly to their mothers in respect to seed yield and some morphological traits including yield attributes. Narrow differences between phenotypic and genotypic coefficients of variation (PCV and GCV for most of the characters revealed less environmental influence on their expression. High values of heritability and genetic advance with high GCV for branch number, plant height, pod number, and seed weight can be considered as favorable attributes for soybean improvement through phenotypic selection and high expected genetic gain can be achieved. Pod and seed number and maturity period appeared to be the first order traits for higher yield and priority should be given in selection due to their strong associations and high magnitudes of direct effects on yield. Cluster analysis grouped 31 genotypes into five groups at the coefficient value of 235. The mutants/genotypes from cluster I and cluster II could be used for hybridization program with the mutants of clusters IV and V in order to develop high yielding mutant-derived soybean varieties for further improvement.

Correlation of the SLAP lesion with lesions of the medial sheath of the biceps tendon and intra-articular subscapularis tendon

Directory of Open Access Journals (Sweden)

Bennett William

2009-01-01

Full Text Available Background: Superior labral anterior to posterior (SLAP lesions have been well described in the literature and are thought to be secondary to traction injuries to the biceps anchor and/or falls on the outstretched arm. The pulley has recently been described as a structure that aids in the prevention of biceps instability. The intra-articular subscapularis insertion (IASS has been noted to contribute to the robust nature of the medial sheath. The purpose of the study was to determine a potential correlation of SLAP lesions and pulley lesions with/without IASS lesions, (hereafter referred to as medial sheath as forces that can disrupt the biceps anchor and may also disrupt structures of the medial sheath or vice-versa. Materials and Methods: Three hundred and sixteen consecutive shoulder arthroscopies performed by one surgeon were reviewed retrospectively. Operative reports and arthroscopic pictures were carefully reviewed with particular attention paid to the labral and pulley pathology. Selection bias was noted as the author had never operated primarily for a Type 1 SLAP lesion. Following, however, and as such, the exclusion criteria, was a Type 1 SLAP. Results: There were a total of 30 SLAP lesions and a total of 126 medial sheath lesions. There were 13 patients who had both SLAP and medial sheath lesions. There were 17 patients who had a SLAP lesion without a medial sheath lesion. There were 96 medial sheath lesions without a SLAP. A comparison of rates between patients who had a medial sheath lesion with a SLAP and those who had a medial sheath lesion without a SLAP, for the 316 patients, and when tested with a Fisher exact test revealed that there was no statistical significance, P = 0.673. The prevalence of SLAP lesions in this population of 316 patients was 9.4%, Buford 1%, medial sheath lesions 39%, and SLAP and medial sheath lesions 4%. Interestingly, there were three Buford complexes, all associated with a SLAP and one Buford complex

Abduction of Arm Facilitates Correction of Kinked Peel-Away Sheath During Subclavian Central Line Placement.

Science.gov (United States)

Kim, Sunghoon

2015-12-01

A tunneled central line catheter placement using a subclavian vein approach can be complicated by an occurrence of peel-away sheath kink which prevents the advancement of the catheter through the sheath. The kink is created due to the angular junction of subclavian and brachiocephalic veins which meet at 90 degree angle. A technique is described which corrects the peel-away sheath kink by extending the subclavian/brachiocephalic vein angle to greater than 90 degrees by abducting the patient's arm. Copyright © 2015 Elsevier Inc. All rights reserved.

Tumor targeted delivery of doxorubicin in malignant peripheral nerve sheath tumors.

Directory of Open Access Journals (Sweden)

A B Madhankumar

Full Text Available Peripheral nerve sheath tumors are benign tumors that have the potential to transform into malignant peripheral nerve sheath tumors (MPNSTs. Interleukin-13 receptor alpha 2 (IL13Rα2 is a cancer associated receptor expressed in glioblastoma and other invasive cancers. We analyzed IL13Rα2 expression in several MPNST cell lines including the STS26T cell line, as well as in several peripheral nerve sheath tumors to utilize the IL13Rα2 receptor as a target for therapy. In our studies, we demonstrated the selective expression of IL13Rα2 in several peripheral nerve sheath tumors by immunohistochemistry (IHC and immunoblots. We established a sciatic nerve MPNST mouse model in NIH III nude mice using a luciferase transfected STS26T MPNST cell line. Similarly, analysis of the mouse sciatic nerves after tumor induction revealed significant expression of IL13Rα2 by IHC when compared to a normal sciatic nerve. IL13 conjugated liposomal doxorubicin was formulated and shown to bind and internalized in the MPNST cell culture model demonstrating cytotoxic effect. Our subsequent in vivo investigation in the STS26T MPNST sciatic nerve tumor model indicated that IL13 conjugated liposomal doxorubicin (IL13LIPDXR was more effective in inhibiting tumor progression compared to unconjugated liposomal doxorubicin (LIPDXR. This further supports that IL13 receptor targeted nanoliposomes is a potential approach for treating MPNSTs.

Sharing mutants and experimental information prepublication using FgMutantDb (https://scabusa.org/FgMutantDb).

Science.gov (United States)

Baldwin, Thomas T; Basenko, Evelina; Harb, Omar; Brown, Neil A; Urban, Martin; Hammond-Kosack, Kim E; Bregitzer, Phil P

2018-06-01

There is no comprehensive storage for generated mutants of Fusarium graminearum or data associated with these mutants. Instead, researchers relied on several independent and non-integrated databases. FgMutantDb was designed as a simple spreadsheet that is accessible globally on the web that will function as a centralized source of information on F. graminearum mutants. FgMutantDb aids in the maintenance and sharing of mutants within a research community. It will serve also as a platform for disseminating prepublication results as well as negative results that often go unreported. Additionally, the highly curated information on mutants in FgMutantDb will be shared with other databases (FungiDB, Ensembl, PhytoPath, and PHI-base) through updating reports. Here we describe the creation and potential usefulness of FgMutantDb to the F. graminearum research community, and provide a tutorial on its use. This type of database could be easily emulated for other fungal species. Published by Elsevier Inc.

Sheath and heat flow of a two-electron-temperature plasma in the presence of electron emission

International Nuclear Information System (INIS)

Sato, Kunihiro; Miyawaki, Fujio

1992-01-01

The electrostatic sheath and the heat flow of a two-electron-temperature plasma in the presence of electron emission are investigated analytically. It is shown that the energy flux is markedly enhanced to a value near the electron free-flow energy flux as a result of considerable reduction of the sheath potential due to electron emission if the fraction of hot electrons at the sheath edge is much smaller than one. If the hot- to cold-electron temperature ratio is of the order of ten and the hot electron density is comparable to the cold electron density, the action of the sheath as a thermal insulator is improved as a result of suppression of electron emission due to the space-charge effect of hot electrons. (author)

Acute optic nerve sheath fenestration with the free-electron laser

Science.gov (United States)

Shen, Jin-Hui; Casagrande, Vivien A.; Joos, Karen M.; Shetlar, Debra J.; Robinson, Richard D.; Head, William S.; Mavity-Hudson, Julia A.; Nunnally, Amy H.

1999-06-01

Purpose: To determine if the free electron laser (FEL) energy can be delivered to a small space to perform optic nerve sheath fenestration with minimal acute nerve damage. Methods: A 530 mm hollow waveguide probe was designed. Optic nerve sheath fenestration (1.0 mm diameter) was performed in 8 rabbits using either the FEL (4 eyes, 6.45mm, 10 Hz, 2 mJ) or a knife (4 eyes). Within 2 hours following surgery, the animals were perfused with aldehyde fixative. The integrity of the optic nerve and glial response at the site of fenestration were evaluated on tissue selections with H&E, and antibodies to S100β or GFAP. Results: Surgery using the FEL probe was found to be technically superior to the knife. The glial reaction was limited to a zone adjacent to the fenestration and was similar in both the FEL and knife incisions. Conclusions: The FEL appears capable of efficiently performing an optic nerve sheath fenestration in a small space with minimal acute damage. Both the FEL and knife incisions result in a rapid glial response at the site of fenestration even when optic nerve integrity is not compromised.

Osteocalcin expressing cells from tendon sheaths in mice contribute to tendon repair by activating Hedgehog signaling

OpenAIRE

Wang, Yi; Zhang, Xu; Huang, Huihui; Xia, Yin; Yao, YiFei; Mak, Arthur Fuk-Tat; Yung, Patrick Shu-Hang; Chan, Kai-Ming; Wang, Li; Zhang, Chenglin; Huang, Yu; Mak, Kingston King-Lun

2017-01-01

Both extrinsic and intrinsic tissues contribute to tendon repair, but the origin and molecular functions of extrinsic tissues in tendon repair are not fully understood. Here we show that tendon sheath cells harbor stem/progenitor cell properties and contribute to tendon repair by activating Hedgehog signaling. We found that Osteocalcin (Bglap) can be used as an adult tendon-sheath-specific marker in mice. Lineage tracing experiments show that Bglap-expressing cells in adult sheath tissues pos...

Optic nerve sheath diameter: A novel way to monitor the brain

Directory of Open Access Journals (Sweden)

Seelora Sahu

2017-01-01

Full Text Available Measurement and monitoring of intracranial pressure is pivotal in management of brain injured patients. As a rapid and easily done bed side measurement, ultrasonography of the optic nerve sheath diameter presents itself as a possible replacement of the conventional invasive methods of intracranial pressure management. In this review we go through the evolution of optic nerve sheath diameter measurement as a novel marker of predicting raised intracranial pressure, the modalities by which it can be measured as well as its correlation with the invasive methods of intracranial pressure monitoring.

CANDU fuel sheath integrity and oxide layer thickness determination by Eddy current technique

International Nuclear Information System (INIS)

Gheorghe, Gabriela; Man, Ion; Parvan, Marcel; Valeca, Serban

2010-01-01

This paper presents results concerning the integrity assessment of the fuel elements cladding and measurements of the oxide layer on sheaths, using the eddy current technique. Flaw detection using eddy current provides information about the integrity of fuel element sheath or presence of defects in the sheath produced by irradiation. The control equipment consists of a flaw detector with eddy currents, operable in the frequency range 10 Hz to 10 MHz, and a differential probe. The calibration of the flaw detector is done using artificial defects (longitudinal, transversal, external and internal notches, bored and unbored holes) obtained on Zircaloy-4 tubes identical to those out of which the sheath of the CANDU fuel element is manufactured (having a diameter of 13.08 mm and a wall thickness of 0.4 mm). When analyzing the behavior of the fuel elements' cladding facing the corrosion is important to know the thickness of the zirconium oxide layer. The calibration of the device measuring the thickness of the oxide layer is done using a Zircaloy-4 tube identical to that which the cladding of the CANDU fuel element is manufactured of, and calibration foils, as well. (authors)

Zircaloy-sheathed element rods fitted with thermo-couples

International Nuclear Information System (INIS)

Bernardy de Sigoyer, B.; Jacques, F.; Thome, P.

1963-01-01

In order to carry out thermal conductivity measurements on UO 2 in conditions similar to those under which fuel rods are used, it was necessary to measure the temperature at the interior of a fuel element sheathed in zircaloy. The temperatures are taken with Thermocoax type thermocouples, that is to say fitted with a very thin sheath of stainless steel or Inconel. It is known also that fusion welding of zircaloy onto stainless steel is impossible and that high temperature welded joints are very difficult because of their aggressiveness. The technique used consists in brazing the thermocouples to relatively large stainless steel parts and then joining these plugs by electron bombardment welding to diffused stainless steel-zircaloy couplings. The properties of these diffused couplings and of the brazed joints were studied; the various stages in the fabrication of the containers are also described. (authors) [fr

The Presence of Turbulent and Ordered Local Structure within the ICME Shock-sheath and Its Contribution to Forbush Decrease

Energy Technology Data Exchange (ETDEWEB)

Shaikh, Zubair; Bhaskar, Ankush [Indian Institute of Geomagnetism (IIG), New Panvel, Navi Mumbai-410218 (India); Raghav, Anil, E-mail: raghavanil1984@gmail.com [University Department of Physics, University of Mumbai, Vidyanagari, Santacruz (E), Mumbai-400098 (India)

2017-08-01

The transient interplanetary disturbances evoke short-time cosmic-ray flux decrease, which is known as Forbush decrease. The traditional model and understanding of Forbush decrease suggest that the sub-structure of an interplanetary counterpart of coronal mass ejection (ICME) independently contributes to cosmic-ray flux decrease. These sub-structures, shock-sheath, and magnetic cloud (MC) manifest as classical two-step Forbush decrease. The recent work by Raghav et al. has shown multi-step decreases and recoveries within the shock-sheath. However, this cannot be explained by the ideal shock-sheath barrier model. Furthermore, they suggested that local structures within the ICME’s sub-structure (MC and shock-sheath) could explain this deviation of the FD profile from the classical FD. Therefore, the present study attempts to investigate the cause of multi-step cosmic-ray flux decrease and respective recovery within the shock-sheath in detail. A 3D-hodogram method is utilized to obtain more details regarding the local structures within the shock-sheath. This method unambiguously suggests the formation of small-scale local structures within the ICME (shock-sheath and even in MC). Moreover, the method could differentiate the turbulent and ordered interplanetary magnetic field (IMF) regions within the sub-structures of ICME. The study explicitly suggests that the turbulent and ordered IMF regions within the shock-sheath do influence cosmic-ray variations differently.

Ratio of sheath thickness to Debye length for a slightly ionized continuum plasma

International Nuclear Information System (INIS)

Hamilton, J.

1980-01-01

The penetration of plasma sheaths for spherical probes in a slightly ionized continuum plasma has been computed for values of epsilon (the ratio of ion to electron temperature) of 0.01 and 1.0 with rhosub(p) (the ratio of probe radius to plasma Debye length) set at 5.10,20 and 30. Values of the potential drops at the sheath boundaries are presented

Coating of Zircaloy sheaths with silica glass using the Sol-Gel technique for protection against oxidation

International Nuclear Information System (INIS)

De Sanctis, O.; Pellegri, N.; Gomez, L.

1990-01-01

With the aim of improving corrosion resistance of Zircaloy, a few Zircaloy sheaths were covered with vitreous silica. Deposition was made by dip coating in tetraetilortosilicate (TEOS) solutions and later densification treatment at 500 degrees C. Oxidation tests were performed and compared with sheaths not covered with silica. As a result, an effective increase in the resistance to dry oxidation was found in sheaths which had been protected. The coating-Zircaloy interface was studied using XPS (scanner). (Author). 6 refs., 3 figs

The effect of an auxiliary discharge on anode sheath potentials in a transverse discharge

International Nuclear Information System (INIS)

Foster, J.E.; Gallimore, A.D.

1997-01-01

A novel scheme that employs the use of an auxiliary discharge has been shown to reduce markedly anode sheath potentials in a transverse discharge. An 8.8 A low-pressure argon discharge in the presence of a transverse magnetic field was used as the plasma source in this study. In such discharges, the transverse flux that is collected by the anode is severely limited due to marked reductions in the transverse diffusion coefficient. Findings of this study indicate that the local electron number density and the transverse flux increase when the auxiliary discharge is operated. Changes in these parameters are reflected in the measured anode sheath voltage. Anode sheath potentials, estimated by using Langmuir probes, were shown to be reduced by over 33% when the auxiliary discharge is operated. These reductions in anode sheath potentials translated into significant reductions in anode power flux as measured using water calorimeter techniques. The reductions in anode power flux also correlate well with changes in the electron transverse flux. Finally, techniques implementing these positive effects in real plasma accelerators are discussed. copyright 1997 American Institute of Physics

Dust charging and charge fluctuations in a weakly collisional radio-frequency sheath at low pressure

International Nuclear Information System (INIS)

Piel, Alexander; Schmidt, Christian

2015-01-01

Models for the charging of dust particles in the bulk plasma and in the sheath region are discussed. A new model is proposed that describes collision-enhanced ion currents in the sheath. The collisions result in a substantial reduction of the negative charge of the dust. Experimental data for the dust charge in the sheath can be described by this model when a Bi-Maxwellian electron distribution is taken into account. Expressions for the dust charging rate for all considered models are presented and their influence on the rise of the kinetic dust temperature is discussed

Normal tendon sheath of the second to fifth fingers as seen on oblique views

Energy Technology Data Exchange (ETDEWEB)

Fischer, E.

1984-01-01

Oblique views of the fingers, using a low kilovolt technique, show a portion of the tendon sheaths which can be regarded as representative of the entire sheath. Because of the varying obliquity of each finger, this proportion differs in the fingers. With increasing age the projected portion of the sheath becomes smaller because it is covered by increasing bone formation in the insertion of the tendon sheat. Normal values have been obtained for adults according to their decades; from these, quite minor degrees of tendon sheat thickening can be determined. In camptodactyly of the fifth finger, which is not uncommon, the tendon sheat may be widened in the absence of a tenosynovitis.

Magneto-optical investigations of Ag-sheathed Bi-2223 tapes with ferromagnetic shielding

International Nuclear Information System (INIS)

Yurchenko, V.V.; Shantsev, D.V.; Galperin, Y.M.; Alamgir, A.K.M.; Han, Z.; Johansen, T.H.

2007-01-01

An increase in the critical current and suppression of AC losses in superconducting wires and tapes with soft magnetic sheath have been predicted theoretically and confirmed experimentally. In this work we present the results of magneto-optical investigations on a series of Ag-sheathed Bi-2223 tapes with Ni coating. We visualize distributions of magnetic field at increasing external field and different temperatures, demonstrating a difference between the flux propagation in the superconductor with Ni rims and a reference sample without Ni coating

Magneto-optical investigations of Ag-sheathed Bi-2223 tapes with ferromagnetic shielding

Energy Technology Data Exchange (ETDEWEB)

Yurchenko, V.V.; Shantsev, D.V.; Galperin, Y.M. [University of Oslo, Department of Physics, P.O. Box 1048, Blindern, 0316 Oslo (Norway); Alamgir, A.K.M.; Han, Z. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Johansen, T.H. [University of Oslo, Department of Physics, P.O. Box 1048, Blindern, 0316 Oslo (Norway)], E-mail: tomhj@fys.uio.no

2007-09-01

An increase in the critical current and suppression of AC losses in superconducting wires and tapes with soft magnetic sheath have been predicted theoretically and confirmed experimentally. In this work we present the results of magneto-optical investigations on a series of Ag-sheathed Bi-2223 tapes with Ni coating. We visualize distributions of magnetic field at increasing external field and different temperatures, demonstrating a difference between the flux propagation in the superconductor with Ni rims and a reference sample without Ni coating.

Retroperitoneal and rectus sheath hematomas.

Science.gov (United States)

Kasotakis, George

2014-02-01

The retroperitoneum is rich in vascular structures and can harbor large hematomas, traumatic or spontaneous. The management of retroperitoneal hematomas depends on the mechanism of injury and whether they are pulsatile/expanding. Rectus sheath hematomas are uncommon abdominal wall hematomas secondary to trauma to the epigastric arteries of the rectus muscle. The common risk factors include anticoagulation, strenuous exercise, coughing, coagulation disorders, and invasive procedures on/through the abdominal wall. The management is largely supportive, with the reversal of anticoagulation and transfusions; angioembolization may be necessary. Copyright © 2014 Elsevier Inc. All rights reserved.

Slit-surface electrospinning: a novel process developed for high-throughput fabrication of core-sheath fibers.

Directory of Open Access Journals (Sweden)

Xuri Yan

Full Text Available In this work, we report on the development of slit-surface electrospinning--a process that co-localizes two solutions along a slit surface to spontaneously emit multiple core-sheath cone-jets at rates of up to 1 L/h. To the best of our knowledge, this is the first time that production of electrospun core-sheath fibers has been scaled to this magnitude. Fibers produced in this study were defect-free (i.e. non-beaded and core-sheath geometry was visually confirmed under scanning electron microscopy. The versatility of our system was demonstrated by fabrication of (1 fibers encapsulating a drug, (2 bicomponent fibers, (3 hollow fibers, and (4 fibers from a polymer that is not normally electrospinnable. Additionally, we demonstrate control of the process by modulating parameters such as flow rate, solution viscosity, and fixture design. The technological achievements demonstrated in this work significantly advance core-sheath electrospinning towards commercial and manufacturing viability.

Formation of Stylet Sheaths in āere (in air from eight species of phytophagous hemipterans from six families (Suborders: Auchenorrhyncha and Sternorrhyncha.

Directory of Open Access Journals (Sweden)

J Kent Morgan

Full Text Available Stylet sheath formation is a common feature among phytophagous hemipterans. These sheaths are considered essential to promote a successful feeding event. Stylet sheath compositions are largely unknown and their mode of solidification remains to be elucidated. This report demonstrates the formation and solidification of in āere (in air produced stylet sheaths by six hemipteran families: Diaphorina citri (Psyllidae, Asian citrus psyllid, Aphis nerii (Aphididae, oleander/milkweed aphid, Toxoptera citricida (Aphididae, brown citrus aphid, Aphis gossypii (Aphididae, cotton melon aphid, Bemisia tabaci biotype B (Aleyrodidae, whitefly, Homalodisca vitripennis (Cicadellidae, glassy-winged sharpshooter, Ferrisia virgata (Pseudococcidae, striped mealybug, and Protopulvinaria pyriformis (Coccidae, pyriform scale. Examination of in āere produced stylet sheaths by confocal and scanning electron microscopy shows a common morphology of an initial flange laid down on the surface of the membrane followed by continuous hollow core structures with sequentially stacked hardened bulbous droplets. Single and multi-branched sheaths were common, whereas mealybug and scale insects typically produced multi-branched sheaths. Micrographs of the in āere formed flanges indicate flange sealing upon stylet bundle extraction in D. citri and the aphids, while the B. tabaci whitefly and H. vitripennis glassy-winged sharpshooter flanges remain unsealed. Structural similarity of in āere sheaths are apparent in stylet sheaths formed in planta, in artificial diets, or in water. The use of 'Solvy', a dissolvable membrane, for intact stylet sheath isolation is reported. These observations illustrate for the first time this mode of stylet sheath synthesis adding to the understanding of stylet sheath formation in phytophagous hemipterans and providing tools for future use in structural and compositional analysis.

significance of rice sheath photosynthesis: yield determination by c ...

African Journals Online (AJOL)

ACSS

1State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha 410125, P.R. China. 2School of ... for contribution rates of sheath photosynthesis to economical yield. ..... related processes during ripening in rice plants.

Addition of rectus sheath relaxation incisions to emergency midline laparotomy for peritonitis to prevent fascial dehiscence.

Science.gov (United States)

Marwah, Sanjay; Marwah, Nisha; Singh, Mandeep; Kapoor, Ajay; Karwasra, Rajender Kumar

2005-02-01

The incidence of fascial dehiscence and incisional hernia after two methods for abdominal wound closure (rectus sheath relaxation incisions and conventional mass closure) was studied in a randomized prospective clinical trial in a consecutive series of 100 patients undergoing midline laparotomy for peritonitis. The two groups were well matched for etiologies of peritonitis, the surgical procedures performed, and the presence of known risk factors for fascial dehiscence. Fifty patients each were randomized either to the conventional continuous mass closure procedure or the rectus sheath relaxation incision technique (designed to increase wound elasticity and decrease tension in the suture line) using identical polypropylene sutures. The incidence of postoperative complications such as duration of ileus, chest infection, and wound infection were not statistically different between the two groups. The intensity of postoperative pain in the rectus sheath relaxation incision group was significantly less. The incidence of wound hematoma was significantly increased in the rectus sheath relaxation incision group. The incidences of fascial dehiscence (16% vs,28%; p cases of peritonitis using the rectus sheath relaxation technique is safe and less painful, provides increased wound elasticity and decreased tension on the suture line, and significantly decreases the incidence of wound dehiscence.

Evaluation of Bcl-2, Bcl-x and Cleaved Caspase-3 in Malignant Peripheral Nerve Sheath Tumors and Neurofibromas

Directory of Open Access Journals (Sweden)

KARIN S. CUNHA

2013-11-01

Full Text Available AIMS: To study the expression of Bcl-2, Bcl-x, as well the presence of cleaved caspase-3 in neurofibromas and malignant peripheral nerve sheath tumors. The expression of Bcl-2 and Bcl-x and the presence of cleaved caspase 3 were compared to clinicopathological features of malignant peripheral nerve sheath tumors and their impact on survival rates were also investigated. MATERIALS AND METHODS: The evaluation of Bcl-2, Bcl-x and cleaved caspase-3 was performed by immunohistochemistry using tissue microarrays in 28 malignant peripheral nerve sheath tumors and 38 neurofibromas. Immunoquantification was performed by computerized digital image analysis. CONCLUSIONS: Apoptosis is altered in neurofibromas and mainly in malignant peripheral nerve sheath tumors. High levels of cleaved caspase-3 are more common in tumors with more aggressive histological features and it is associated with lower disease free survival of patients with malignant peripheral nerve sheath tumors.

A matching approach to communicate through the plasma sheath surrounding a hypersonic vehicle

International Nuclear Information System (INIS)

Gao, Xiaotian; Jiang, Binhao

2015-01-01

In order to overcome the communication blackout problem suffered by hypersonic vehicles, a matching approach has been proposed for the first time in this paper. It utilizes a double-positive (DPS) material layer surrounding a hypersonic vehicle antenna to match with the plasma sheath enclosing the vehicle. Analytical analysis and numerical results indicate a resonance between the matched layer and the plasma sheath will be formed to mitigate the blackout problem in some conditions. The calculated results present a perfect radiated performance of the antenna, when the match is exactly built between these two layers. The effects of the parameters of the plasma sheath have been researched by numerical methods. Based on these results, the proposed approach is easier to realize and more flexible to the varying radiated conditions in hypersonic flight comparing with other methods

Magnetic storm generation by large-scale complex structure Sheath/ICME

Science.gov (United States)

Grigorenko, E. E.; Yermolaev, Y. I.; Lodkina, I. G.; Yermolaev, M. Y.; Riazantseva, M.; Borodkova, N. L.

2017-12-01

We study temporal profiles of interplanetary plasma and magnetic field parameters as well as magnetospheric indices. We use our catalog of large-scale solar wind phenomena for 1976-2000 interval (see the catalog for 1976-2016 in web-side ftp://ftp.iki.rssi.ru/pub/omni/ prepared on basis of OMNI database (Yermolaev et al., 2009)) and the double superposed epoch analysis method (Yermolaev et al., 2010). Our analysis showed (Yermolaev et al., 2015) that average profiles of Dst and Dst* indices decrease in Sheath interval (magnetic storm activity increases) and increase in ICME interval. This profile coincides with inverted distribution of storm numbers in both intervals (Yermolaev et al., 2017). This behavior is explained by following reasons. (1) IMF magnitude in Sheath is higher than in Ejecta and closed to value in MC. (2) Sheath has 1.5 higher efficiency of storm generation than ICME (Nikolaeva et al., 2015). The most part of so-called CME-induced storms are really Sheath-induced storms and this fact should be taken into account during Space Weather prediction. The work was in part supported by the Russian Science Foundation, grant 16-12-10062. References. 1. Nikolaeva N.S., Y. I. Yermolaev and I. G. Lodkina (2015), Modeling of the corrected Dst* index temporal profile on the main phase of the magnetic storms generated by different types of solar wind, Cosmic Res., 53(2), 119-127 2. Yermolaev Yu. I., N. S. Nikolaeva, I. G. Lodkina and M. Yu. Yermolaev (2009), Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Res., , 47(2), 81-94 3. Yermolaev, Y. I., N. S. Nikolaeva, I. G. Lodkina, and M. Y. Yermolaev (2010), Specific interplanetary conditions for CIR-induced, Sheath-induced, and ICME-induced geomagnetic storms obtained by double superposed epoch analysis, Ann. Geophys., 28, 2177-2186 4. Yermolaev Yu. I., I. G. Lodkina, N. S. Nikolaeva and M. Yu. Yermolaev (2015), Dynamics of large-scale solar wind streams obtained by the double superposed epoch

The Bohm criterion for a dusty plasma sheath

Indian Academy of Sciences (India)

undergo temperature fluctuations due to collision, the mean square fluctuation in their temperature is much less than the equilibrium temperature. The problem of sheath dynamics with the plasma–wall interactions is of great importance in a number of areas, viz., plasma ion implantation, high-density com- puter chip ...

Scattering characteristics of electromagnetic waves in time and space inhomogeneous weakly ionized dusty plasma sheath

Science.gov (United States)

Guo, Li-xin; Chen, Wei; Li, Jiang-ting; Ren, Yi; Liu, Song-hua

2018-05-01

The dielectric coefficient of a weakly ionised dusty plasma is used to establish a three-dimensional time and space inhomogeneous dusty plasma sheath. The effects of scattering on electromagnetic (EM) waves in this dusty plasma sheath are investigated using the auxiliary differential equation finite-difference time-domain method. Backward radar cross-sectional values of various parameters, including the dust particle radius, charging frequency of dust particles, dust particle concentration, effective collision frequency, rate of the electron density variation with time, angle of EM wave incidence, and plasma frequency, are analysed within the time and space inhomogeneous plasma sheath. The results show the noticeable effects of dusty plasma parameters on EM waves.

An extension of a high temperature creep model to account for fuel sheath oxidation

International Nuclear Information System (INIS)

Boccolini, G.; Valli, G.

1983-01-01

Starting from the high-temperature creep model for Zircaloy fuel sheathing, the NIRVANA (developed by AECL), a multilayer model, is proposed in this paper: it includes the outer oxide plus alpha retained layers, and the inner core of beta or alpha plus beta material, all constrained to deform with the same creep rate. The model has been incorporated into the SPARA fuel computer code developed for the transient analysis of fuel rod behaviour in the CIRENE prototype reactor, but it is in principle valid for all Zircaloy fuel sheathings. Its predictions are compared with experimental results from burst tests on BWR and PWR type sheaths; the tests were carried out at CNEN under two research contracts with Ansaldo Meccanico Nucleare and Sigen-Sopren, respectively

Mutants induced in winter rye (Secale cereale L.): Short straw-mutant No. 2714 and late-senescence mutant

Energy Technology Data Exchange (ETDEWEB)

Muszynski, S; Darlewska, M [Department of Plant Breeding and Seed Science, Warsaw Agricultural University, Warsaw (Poland)

1990-01-01

Full text: Mutants were induced by treating dormant seeds with ionizing radiation (fast neutrons) or chemicals (N-nitroso-N-ethyl urea or sodium azide). Among several mutants obtained, of special value is the short-straw mutant No. 2714 and a late senescent mutant. (author)

Applicability of the Child-Langmuir laws versions for describing the glow discharge cathode sheath in CO2

Science.gov (United States)

Lisovskiy, Valeriy; Krol, Hennadii; Osmayev, Ruslan; Yegorenkov, Vladimir

2016-09-01

This work is devoted to the determination of the law that may be applicable to the description of the cathode sheath in CO2. To this end three versions of the Child-Langmuir law have been considered - a collision free one (for the ions moving through a cathode sheath without collisions with gas molecules) as well as two collision- related versions- one for a constant mean free path of positive ions and one for a constant mobility of positive ions. The current-voltage characteristics and the cathode sheath thickness of the glow discharge in carbon oxide have been simultaneously measured in the pressure range from 0.05 to 1 Torr and with the discharge current values up to 80 mA. The inter-electrode distance has been chosen such that the discharge consists only of the cathode sheath and a small portion of the negative glow, i.e. the experiments have been performed in short tubes. In this case the voltage drop across the cathode sheath is equal approximately to the voltage drop across the electrodes. In the whole range of the discharge conditions we have studied the cathode sheath characteristics are found to obey correctly only to the Child-Langmuir law version with a constant ion mobility. The reason for this phenomenon may be related with a significant conversion of carbon dioxide molecules.

X-band microwave generation caused by plasma-sheath instability

International Nuclear Information System (INIS)

Bliokh, Y.; Felsteiner, J.; Slutsker, Ya. Z.

2012-01-01

It is well known that oscillations at the electron plasma frequency may appear due to instability of the plasma sheath near a positively biased electrode immersed in plasma. This instability is caused by transit-time effects when electrons, collected by this electrode, pass through the sheath. Such oscillations appear as low-power short spikes due to additional ionization of a neutral gas in the electrode vicinity. Herein we present first results obtained when the additional ionization was eliminated. We succeeded in prolonging the oscillations during the whole time a positive bias was applied to the electrode. These oscillations could be obtained at much higher frequency than previously reported (tens of GHz compared to few hundreds of MHz) and power of tens of mW. These results in combination with presented theoretical estimations may be useful, e.g., for plasma diagnostics.

Texture gradients in Fe-sheathed ex situ produced MgB2 tapes

International Nuclear Information System (INIS)

Lezza, P; Gladyshevskii, R; Abaecherli, V; Fluekiger, R

2006-01-01

Superconducting Fe-sheathed MgB 2 monofilamentary tapes have been fabricated by the powder-in-tube technique, varying the particle size of the starting MgB 2 powder and applying either cold or hot rolling during the last deformation process. Measurements of the critical current density J c with the magnetic field applied parallel or perpendicular to the tape surface revealed a pronounced anisotropy for the cold rolled tapes, which was found to increase with increasing particle size and magnetic field strength. The microstructural origin of the J c anisotropy was confirmed by means of x-ray diffraction performed on the filaments after mechanical removal of the sheath. The local texture was studied in a series of diffraction patterns collected at different distances from the filament centre, removing each time some 25 μm of the filament thickness. In the cold rolled tapes, the average orientation of the MgB 2 grains was found to approach a preferred orientation with the crystallographic c-axis perpendicular to the tape surface, near the interface with the sheath; however, the misalignment angle increased towards the centre of the tape. In the hot rolled tapes, for which no J c anisotropy was observed, the grains were found to be approximately randomly oriented. Roughness measurements performed on the side of the Fe sheath in contact with the MgB 2 filament are in agreement with the difference in texture observed for cold and hot rolled tapes

Hyphenation of capillary high-performance ion-exchange chromatography with mass spectrometry using sheath-flow electrospray ionization.

Science.gov (United States)

Kochmann, Sven; Matysik, Frank-Michael

2014-12-15

Mass spectrometry (MS) is an attractive method for extending capillary-size ion chromatography (cHPIC) to create a valuable technique for speciation analysis. For hyphenation, the aqueous effluent of cHPIC has to be transformed into a volatile mixture for MS while preserving analytical concentrations as well as peak shapes during transfer from cHPIC to MS. Finally, the approach should technically be flexible and easy-to-use. A combination of cHPIC and sheath-flow electrospray ionization (ESI)-MS offers to solve all these challenges. cHPIC/sheath-flow-ESI-TOFMS was used in this study for the speciation analysis of various arsenic model compounds. These model compounds were analyzed with different hyphenation setups and configurations of cHPIC/MS and their respective assets and drawbacks were examined and discussed. The parameters (flow rate and composition of sheath liquid) of sheath-flow ESI and their influence on the performance of the spray and the sensitivity of the detector were investigated and compared with those of sheathless ESI. Using an injection valve to couple cHPIC and MS was found to be the best method for hyphenation, since it constitutes a flexible and dead-volume-free approach. The investigation of sheath-flow ESI revealed that the flow rate of the sheath liquid has to resemble the flow rate of the IC effluent to ensure a stable spray and that a composition of 2-propanol/water/ammonia at 50:50:0.2 (v/v/v) suits most applications without unilaterally promoting the sensitivity for either organic or inorganic compounds. The optimized setup and conditions were successfully applied to the analysis of a mixture of important arsenic species and used to determine limits of detection of organic and inorganic arsenic species (3.7 µg L(-1) elemental arsenic). A method for cHPIC/sheath-flow-ESI-MS was developed. The method was shown to be a valuable tool for speciation and trace analysis. It features no dead volume, fast transfer from IC to MS, only minimal

Ultrastructure of the extracellular matrix of bovine dura mater, optic nerve sheath and sclera.

Science.gov (United States)

Raspanti, M; Marchini, M; Della Pasqua, V; Strocchi, R; Ruggeri, A

1992-10-01

The sclera, the outermost sheath of the optic nerve and the dura mater have been investigated histologically and ultrastructurally. Although these tissues appear very similar under the light microscope, being dense connective tissues mainly composed of collagen bundles and a limited amount of cells and elastic fibres, they exhibit subtle differences on electron microscopy. In the dura and sclera collagen appears in the form of large, nonuniform fibrils, similar to those commonly found in tendons, while in the optic nerve sheath the fibrils appear smaller and uniform, similar to those commonly observed in reticular tissues, vessel walls and skin. Freeze-fracture also reveals these fibrils to have different subfibrillar architectures, straight or helical, which correspond to 2 distinct forms of collagen fibril previously described (Raspanti et al. 1989). The other extracellular matrix components also vary with the particular collagen fibril structure. Despite their common embryological derivation, the dura mater, optic nerve sheath and sclera exhibit diversification of their extracellular matrix consistent with the mechanical loads to which these tissues are subjected. Our observations indicate that the outermost sheath of the optic nerve resembles the epineurium of peripheral nerves rather than the dura to which it is commonly likened.

A Novel Technique Using a Protection Filter During Fibrin Sheath Removal for Implanted Venous Access Device Dysfunction

Energy Technology Data Exchange (ETDEWEB)

Sotiriadis, Charalampos; Hajdu, Steven David [University Hospital of Lausanne, Cardiothoracic and Vascular Unit, Department of Radiology (Switzerland); Degrauwe, Sophie [University Hospital of Lausanne, Department of Cardiology (Switzerland); Barras, Heloise; Qanadli, Salah Dine, E-mail: salah.qanadli@chuv.ch [University Hospital of Lausanne, Cardiothoracic and Vascular Unit, Department of Radiology (Switzerland)

2016-08-15

With the increased use of implanted venous access devices (IVADs) for continuous long-term venous access, several techniques such as percutaneous endovascular fibrin sheath removal, have been described, to maintain catheter function. Most standard techniques do not capture the stripped fibrin sheath, which is subsequently released in the pulmonary circulation and may lead to symptomatic pulmonary embolism. The presented case describes an endovascular technique which includes stripping, capture, and removal of fibrin sheath using a novel filter device. A 64-year-old woman presented with IVAD dysfunction. Stripping was performed using a co-axial snare to the filter to capture the fibrin sheath. The captured fragment was subsequently removed for visual and pathological verification. No immediate complication was observed and the patient was discharged the day of the procedure.

Genomic and Expression Profiling of Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis Patients

Science.gov (United States)

2008-05-01

DAMD17-03-1-0297 Title: Genomic and Expression Pr ofiling of Benign and Malignant Nerve Sheath Tumors in Neurofibromatosis Patients...have determined the gene expression signature for benign and malignant peripheral nerve sheath tumors and found that the major trend in transformation...However, EGFR data in soft tissue neoplasms is limited. Using a variety of benign and malignant spindle cell neoplasms, we assessed EGFR status by

Extraction of antioxidant pigments from dye sorghum leaf sheaths

NARCIS (Netherlands)

Kayode, A.P.P.; Bara, C.A.; Dalode-Vieira, G.; Linnemann, A.R.; Nout, M.J.R.

2012-01-01

Extraction of antioxidant biocolorant pigments from leaf sheaths of dye sorghum was optimized. Effects of temperature and ethanol concentration of the extraction solvent on the concentrations of the 3-deoxyanthocyanidins, total phenolics and total anthocyanins, and the colour parameters of the

Ganglion of the Flexor Tendon Sheath at the A2 Pulley - Case Report

Directory of Open Access Journals (Sweden)

P Gunaseelan

2015-03-01

Full Text Available There are few reported cases of flexor tendon sheath ganglion arising from the A2 pulley. We report a case of a flexor tendon sheath ganglion in a 17-year old female who presented with pain, triggering and a swelling at the base of her right ring finger. During the excision biopsy, a ganglion measuring 0.5×0.8×0.4 cm in size was removed from the A2 pulley area.

Physics of the intermediate layer between a plasma and a collisionless sheath and mathematical meaning of the Bohm criterion

Energy Technology Data Exchange (ETDEWEB)

Almeida, N. A.; Benilov, M. S. [Departamento de Fisica, CCCEE, Universidade da Madeira Largo do Municipio, 9000 Funchal (Portugal)

2012-07-15

A transformation of the ion momentum equation simplifies a mathematical description of the transition layer between a quasi-neutral plasma and a collisionless sheath and clearly reveals the physics involved. Balance of forces acting on the ion fluid is delicate in the vicinity of the sonic point and weak effects come into play. For this reason, the passage of the ion fluid through the sonic point, which occurs in the transition layer, is governed not only by inertia and electrostatic force but also by space charge and ion-atom collisions and/or ionization. Occurrence of different scenarios of asymptotic matching in the plasma-sheath transition is analyzed by means of simple mathematical examples, asymptotic estimates, and numerical calculations. In the case of a collisionless sheath, the ion speed distribution plotted on the logarithmic scale reveals a plateau in the intermediate region between the sheath and the presheath. The value corresponding to this plateau has the meaning of speed with which ions leave the presheath and enter the sheath; the Bohm speed. The plateau is pronounced reasonably well provided that the ratio of the Debye length to the ion mean free path is of the order of 10{sup -3} or smaller. There is no such plateau if the sheath is collisional and hence no sense in talking of a speed with which ions enter the sheath.

STRETCHY ELECTRONICS. Hierarchically buckled sheath-core fibers for superelastic electronics, sensors, and muscles.

Science.gov (United States)

Liu, Z F; Fang, S; Moura, F A; Ding, J N; Jiang, N; Di, J; Zhang, M; Lepró, X; Galvão, D S; Haines, C S; Yuan, N Y; Yin, S G; Lee, D W; Wang, R; Wang, H Y; Lv, W; Dong, C; Zhang, R C; Chen, M J; Yin, Q; Chong, Y T; Zhang, R; Wang, X; Lima, M D; Ovalle-Robles, R; Qian, D; Lu, H; Baughman, R H

2015-07-24

Superelastic conducting fibers with improved properties and functionalities are needed for diverse applications. Here we report the fabrication of highly stretchable (up to 1320%) sheath-core conducting fibers created by wrapping carbon nanotube sheets oriented in the fiber direction on stretched rubber fiber cores. The resulting structure exhibited distinct short- and long-period sheath buckling that occurred reversibly out of phase in the axial and belt directions, enabling a resistance change of less than 5% for a 1000% stretch. By including other rubber and carbon nanotube sheath layers, we demonstrated strain sensors generating an 860% capacitance change and electrically powered torsional muscles operating reversibly by a coupled tension-to-torsion actuation mechanism. Using theory, we quantitatively explain the complementary effects of an increase in muscle length and a large positive Poisson's ratio on torsional actuation and electronic properties. Copyright © 2015, American Association for the Advancement of Science.

Effects of a reentry plasma sheath on the beam pointing properties of an array antenna

Directory of Open Access Journals (Sweden)

Bowen Bai

2018-03-01

Full Text Available The reduction in the gain of an on-board antenna caused by a reentry plasma sheath is an important effect that contributes to the reentry “blackout” problem. Using phased array antenna and beamforming technology could provide higher gain and an increase in the communication signal intensity. The attenuation and phase delay of the electromagnetic (EM waves transmitting through the plasma sheath are direction-dependent, and the radiation pattern of the phased array antenna is affected, leading to a deviation in the beam pointing. In this paper, the far-field pattern of a planar array antenna covered by a plasma sheath is deduced analytically by considering both refraction and mutual coupling effects. A comparison between the analytic results and the results from an electromagnetic simulation is carried out. The effect of the plasma sheath on the radiation pattern and the beam pointing errors of the phased array antenna is studied systematically, and the derived results could provide useful information for the correction of pointing errors.

The normal tendon sheath of the second to fifth fingers as seen on oblique views

International Nuclear Information System (INIS)

Fischer, E.

1984-01-01

Oblique views of the fingers, using a low kilovolt technique, show a portion of the tendon sheaths which can be regarded as representative of the entire sheath. Because of the varying obliquity of each finger, this proportion differs in the fingers. With increasing age the projected portion of the sheath becomes smaller because it is covered by increasing bone formation in the insertion of the tendon sheat. Normal values have been obtained for adults according to their decades; from these, quite minor degrees of tendon sheat thickening can be determined. In camptodactyly of the fifth finger, which is not uncommon, the tendon sheat may be widened in the absence of a tenosynovitis. (orig.) [de

Salvianolic acid B protects the myelin sheath around injured spinal cord axons

Directory of Open Access Journals (Sweden)

Zhe Zhu

2016-01-01

Full Text Available Salvianolic acid B, an active pharmaceutical compound present in Salvia miltiorrhiza, exerts a neuroprotective effect in animal models of brain and spinal cord injury. Salvianolic acid B can promote recovery of neurological function; however, its protective effect on the myelin sheath after spinal cord injury remains poorly understood. Thus, in this study, in vitro tests showed that salvianolic acid B contributed to oligodendrocyte precursor cell differentiation, and the most effective dose was 20 μg/mL. For in vivo investigation, rats with spinal cord injury were intraperitoneally injected with 20 mg/kg salvianolic acid B for 8 weeks. The amount of myelin sheath and the number of regenerating axons increased, neurological function recovered, and caspase-3 expression was decreased in the spinal cord of salvianolic acid B-treated animals compared with untreated control rats. These results indicate that salvianolic acid B can protect axons and the myelin sheath, and can promote the recovery of neurological function. Its mechanism of action is likely to be associated with inhibiting apoptosis and promoting the differentiation and maturation of oligodendrocyte precursor cells.

3D geometry and kinematic evolution of the Wadi Mayh sheath fold, Oman, using detailed mapping from high-resolution photography

Science.gov (United States)

Cornish, Sam; Searle, Mike

2017-08-01

The Wadi Mayh sheath fold in north-eastern Oman is one of the largest and best-exposed sheath folds known, and presents a unique opportunity to better understand this somewhat enigmatic style of deformation. We undertook high-resolution photographic surveying along Wadi Mayh to document the sheath fold in 61 georeferenced panoramic photomerges. Here we present ten such images that provide a structural interpretation of the sheath fold and surrounding structure. We resolve this structure in a simplified three-dimensional model and in two orthogonal cross sections, and propose a kinematic evolution to explain the geometry. The Wadi Mayh sheath fold is the most prominent example within what we suggest is a composite sequence of sheath folds, which is itself enclosed within a SSW-closing recumbent syncline at the base of the major Saih Hatat nappe. Sheath folding is accommodated within Permian Saiq Formation limestones showing carpholite assemblages (6-8 kbar; 275-375 °C). A major discontinuity separates this sequence from enveloping older rock units. The sequence formed during progressive top-to-north, ductile shearing as the overlying nappe migrated northwards with respect to the underthrusting Hulw unit. This process occurred during SSW-directed exhumation of partially subducted continental crust in NE Oman, approximately 15 Ma after obduction of the Oman ophiolite initiated.

A study of the effect of circumferential temperature variations on fuel-sheath strain in an inert atmosphere

International Nuclear Information System (INIS)

Ferner, J.; Rondeau, R.K.; Rosinger, H.E.

1983-07-01

A failure model for Zircaloy-4 fuel sheaths has been developed and used to predict the effect of circumferential temperature variations (ΔT) on fuel-sheath strain behaviour in an inert atmosphere. In addition, experimental data were generated for fuel-sheath failures in the α and (α+β)-phase regions and compared to the predictions of the model. For both the experimental data and the model predictions it was found that increasing ΔT decreases sheath strain. Most of the reduction in burst strain with increasing ΔT occurs in the first 15 K to 20 K. For high ΔT values, burst strains in the α- and (α+β)-phase regions tend to an asymptotic value in the range 5 to 20 percent, irrespective of both heating rate and circumferential temperature variation. The BURST-2 computer code was used for these calculations

FUNCTION OF MALATDEHYDROGENASE COMPLEX OF MAIZE MESOPHYLL AND BUNDLE SHEATH CELLS UNDER SALT STRESS CONDITION

Directory of Open Access Journals (Sweden)

Еprintsev А.Т.

2006-12-01

Full Text Available Salt-induced changes in malatdehydrogenase system activity make the essential contribution to cell adaptation to stress condition. The enzyme systems of C4-plants are most interesting due to their ability for adaptation to environment conditions. The role of separate components of malatdehydrogenase complex of mesophyll and bundle sheath cells of corn in formation of adaptive reaction in stressful conditions is investigated in presented work.The activation of all enzymes of malatdehydrogenase system and the subsequent decrease in their activity was observed in mesophyll durring the first stage of adaptation to salt influence. In bundle sheath cells such parameters are differed from control less essentially. Fast accumulation of piruvate in cells and malate in both investigated tissues was induced. The further salinity led to falling of concentration this intermediate. The concentration of piruvate was below control level, and it was raised by the end of an exposition.The results show that sodium chloride causes induction of Krebs-cycle in mesophyll and bundle sheath cells of corn and intensification of Hatch-Slack cycle. The described differences in function malatdehydrogenase systems of mesophyll and bundle sheath cells of leaves of corn under salinity mainly consist of the activity of enzymes of a studied complex in bundle sheath cells is subject to the minimal changes in comparison with mesophyll. Role of this enzymesystem in mechanisms of adaptive reaction of various tissues of corn to salt stress is discussed.

Mechanical characterisation of porcine rectus sheath under uniaxial and biaxial tension.

LENUS (Irish Health Repository)

Lyons, Mathew

2014-06-03

Incisional hernia development is a significant complication after laparoscopic abdominal surgery. Intra-abdominal pressure (IAP) is known to initiate the extrusion of intestines through the abdominal wall, but there is limited data on the mechanics of IAP generation and the structural properties of rectus sheath. This paper presents an explanation of the mechanics of IAP development, a study of the uniaxial and biaxial tensile properties of porcine rectus sheath, and a simple computational investigation of the tissue. Analysis using Laplace׳s law showed a circumferential stress in the abdominal wall of approx. 1.1MPa due to an IAP of 11kPa, commonly seen during coughing. Uniaxial and biaxial tensile tests were conducted on samples of porcine rectus sheath to characterise the stress-stretch responses of the tissue. Under uniaxial tension, fibre direction samples failed on average at a stress of 4.5MPa at a stretch of 1.07 while cross-fibre samples failed at a stress of 1.6MPa under a stretch of 1.29. Under equi-biaxial tension, failure occurred at 1.6MPa with the fibre direction stretching to only 1.02 while the cross-fibre direction stretched to 1.13. Uniaxial and biaxial stress-stretch plots are presented allowing detailed modelling of the tissue either in silico or in a surrogate material. An FeBio computational model of the tissue is presented using a combination of an Ogden and an exponential power law model to represent the matrix and fibres respectively. The structural properties of porcine rectus sheath have been characterised and add to the small set of human data in the literature with which it may be possible to develop methods to reduce the incidence of incisional hernia development.

Malignant peripheral nerve sheath tumor of the oculomotor nerve

DEFF Research Database (Denmark)

Kozic, D; Nagulic, M; Ostojic, J

2006-01-01

We present the short-term follow-up magnetic resonance (MR) studies and 1H-MR spectroscopy in a child with malignant peripheral nerve sheath tumor of the oculomotor nerve associated with other less aggressive cranial nerve schwannomas. The tumor revealed perineural extension and diffuse nerve...

Three-dimensional Doppler ultrasound findings in healthy wrist and finger tendon sheaths

DEFF Research Database (Denmark)

Ammitzboll-Danielsen, Mads; Janta, Iustina; Torp-Pedersen, Søren

2016-01-01

interpretation of Doppler signals when diagnosing tenosynovitis. Method Forty healthy participants (20 women and 20 men age 23-67 years) without prior history of arthritis, tendon diseases or present pain in their hands were included. Twenty participants had 3D Doppler US of the second and third finger...... participant. No significant difference in feeding vessels was seen between the radial and carpal level in the wrist (p = 0.06) or between the second and third flexor tendon sheath (p = 0.84). Conclusion Doppler findings in or in close proximity to the tendon sheaths were common in wrists and fingers...

Discrete focusing effect of positive ions by a plasma-sheath lens

International Nuclear Information System (INIS)

Stamate, E.; Sugai, H.

2005-01-01

We demonstrate that the sheath created adjacent to the surface of a negatively biased electrode that interfaces an insulator acts as a lens that focuses the positive ions to distinct regions on the surface. Thus, the positive ion flux is discrete, leading to the formation of a passive surface, of no ion impact, near the edge and an active surface at the center. Trajectories of positive ions within the sheath are obtained by solving in three dimensions the Poisson equation for electrodes of different geometry. Simulations are confirmed by developing the ion flux profile on the electrode surface as the sputtering pattern produced by ion impact. Measurements are performed in a dc plasma produced in Ar gas

Electromagnetic particle in cell modeling of the plasma focus: Current sheath formation and lift off

International Nuclear Information System (INIS)

Seng, Y. S.; Lee, P.; Rawat, R. S.

2014-01-01

The shaping and formation of the current sheath takes place in the breakdown phase of a plasma focus device and critically controls the device performance. Electrostatic particle in cell codes, with magnetic effects ignored, have been used to model the breakdown phase. This Letter reports the successful development and implementation of an electromagnetic particle in cell (EMPIC) code, including magnetic effects self-consistently, to simulate the breakdown phase; from the ionization, localization and gliding discharge along the insulator to the time instant of current sheath lift off. The magnetic field was found to be appreciable from the time the current sheath came into contact with the anode with increased local current, initiating the voltage breakdown of the device as a result

Effects of fast monoenergetic electrons on the ion dynamics near the cathode in a pulsed direct current plasma sheath

International Nuclear Information System (INIS)

Sharifian, M.; Shokri, B.

2008-01-01

A detailed one-dimensional simulation of the ion dynamics of the plasma sheath near a substrate (cathode) in the presence of fast monoenergetic electrons has been carried out in this article. The sheath evolution is investigated by using a fluid model assuming that the ions, plasma electrons and monoenergetic, fast electrons act as three fluids (fluid approach). The effect of the density of fast electrons on the ion density, ion velocity, and ion energy near the cathode and the evolution of the sheath boundary in front of the cathode are separately explored. Also, the variation of the ion velocity and ion density at the vicinity of the cathode as a function of time is investigated in the absence and presence of the electron beam. Results indicate that the presence of fast electrons in the sheath causes significant change in the sheath thickness and therefore basically changes the ion velocity, ion density, and ion impact energy on the cathode compared to the absence of the electron beam case

The influence of the breakdown electric field in the configuration of lightning corona sheath on charge distribution in the channel

Science.gov (United States)

Ignjatovic, Milan; Cvetic, Jovan; Heidler, Fridolin; Markovic, Slavoljub; Djuric, Radivoje

2014-11-01

A model of corona sheath that surrounds the thin core of the lightning channel has been investigated by using a generalized traveling current source return stroke model. The lightning channel is modeled by a charged corona sheath that stretches around a highly conductive central core through which the main current flows. The channel core with the negatively charged outer channel sheath forms a strong electric field, with an overall radial orientation. The return stroke process is modeled as the negative leader charge in the corona sheath being discharged by the positive charge coming from the channel core. Expressions that describe how the corona sheath radius evolves during the return stroke are obtained from the corona sheath model, which predicts charge motion within the sheath. The corona sheath model, set forth by Maslowski and Rakov (2006), Tausanovic et al. (2010), Marjanovic and Cvetic (2009), Cvetic et al. (2011) and Cvetic et al. (2012), divides the sheath onto three zones: zone 1 (surrounding the channel core with net positive charge), zone 2 (surrounding zone 1 with negative charge) and zone 3 (the outer zone, representing uncharged virgin air). In the present study, we have assumed a constant electric field inside zone 1, as suggested by experimental research of corona discharges in coaxial geometry conducted by Cooray (2000). The present investigation builds upon previous studies by Tausanovic et al. (2010) and Cvetic et al. (2012) in several ways. The value of the breakdown electric field has been varied for probing its effect on channel charge distribution prior and during the return stroke. With the aim of investigating initial space charge distribution along the channel, total electric field at the outer surface of the channel corona sheath, just before the return stroke, is calculated and compared for various return stroke models. A self-consistent algorithm is applied to the generalized traveling current source return stroke model, so that the

Fine structure of modal focusing effect in a three dimensional plasma-sheath-lens formed by disk electrodes

DEFF Research Database (Denmark)

Stamate, Eugen; Yamaguchi, Masahito

2015-01-01

Modal and discrete focusing effects associated with three-dimensional plasma-sheath-lenses show promising potential for applications in ion beam extraction, mass spectrometry, plasma diagnostics and for basic studies of plasma sheath. The ion focusing properties can be adjusted by controlling the...

An analytic expression for the sheath criterion in magnetized plasmas with multi-charged ion species

International Nuclear Information System (INIS)

Hatami, M. M.

2015-01-01

The generalized Bohm criterion in magnetized multi-component plasmas consisting of multi-charged positive and negative ion species and electrons is analytically investigated by using the hydrodynamic model. It is assumed that the electrons and negative ion density distributions are the Boltzmann distribution with different temperatures and the positive ions enter into the sheath region obliquely. Our results show that the positive and negative ion temperatures, the orientation of the applied magnetic field and the charge number of positive and negative ions strongly affect the Bohm criterion in these multi-component plasmas. To determine the validity of our derived generalized Bohm criterion, it reduced to some familiar physical condition and it is shown that monotonically reduction of the positive ion density distribution leading to the sheath formation occurs only when entrance velocity of ion into the sheath satisfies the obtained Bohm criterion. Also, as a practical application of the obtained Bohm criterion, effects of the ionic temperature and concentration as well as magnetic field on the behavior of the charged particle density distributions and so the sheath thickness of a magnetized plasma consisting of electrons and singly charged positive and negative ion species are studied numerically

Study on the Mechanical Properties of Stay Cable HDPE Sheathing Fatigue in Dynamic Bridge Environments

Directory of Open Access Journals (Sweden)

Danhui Dan

2015-08-01

Full Text Available As the main force-bearing component of a cable-stayed bridge, a durable stay cable is paramount to the safety and durability of the entire bridge. High-density polyethylene (HDPE sheathing is the main protective component of a stay cable and is the key to insuring cable durability. To address the issue of HDPE sheathing fracture on service, strain level data for in-service, HDPE bridge cable sheathing was used in this study as the basis for HDPE material aging and fatigue testing. A fatigue yield phenomenon with a yield platform on the hysteresis curve of the fatigue cycles is observed by the fatigue test. The parameters to describe this phenomenon are proposed and defined in this paper. A preliminary examination of the relationship between these parameters and the factors, such as the number of cycles, the strain amplitude, and strain rate, are presented. Based on the results obtained, it is suggested that the condition of fatigue yield of HDPE sheathing be defined as the fatigue durability limit state for the purposes of durability design, assessment, and protection of cable-stayed bridges.

Out-of-pile fatigue tests on Zircaloy CANDU sheaths

International Nuclear Information System (INIS)

Roth, Maria; Ciocanescu, Marin; Gheorghiu, Constantin; Pitigoi, Vasile; Ducu, Catalin; Malinovschi, Viorel

2005-01-01

The paper outlines the achievements in the nuclear research field of cooperation on Nuclear Fuel performed as part of the collaboration under the Memorandum of Understanding, settled between Atomic Energy of Canada Limited (AECL) and Institute for Nuclear Research (ICN), The sheath behavior was simulated using out-of-pile fatigue tests, in conditions identical with those met during the operation in power cycling of CANDU reactor, except for irradiation. A special test rig, designed and carried-out at ICN ensured the experimental requirements according to the Canadian testing procedure. The description of the experimental setup and monitoring of testing parameters were also done. The fatigue life time, expressed as number of cycles to rupture (N), was measured as a function of the total strain amplitude (e) induced in the Zircaloy-4 sheath samples. Strain-Life time fatigue dependence (e-N) under low cycle fatigue conditions was also verified using the Coffin-Manson correlation. (authors)

Thermionic emission from monolayer graphene, sheath formation and its feasibility towards thermionic converters

Science.gov (United States)

Misra, Shikha; Upadhyay Kahaly, M.; Mishra, S. K.

2017-02-01

A formalism describing the thermionic emission from a single layer graphene sheet operating at a finite temperature and the consequent formation of the thermionic sheath in its proximity has been established. The formulation takes account of two dimensional densities of state configuration, Fermi-Dirac (f-d) statistics of the electron energy distribution, Fowler's treatment of electron emission, and Poisson's equation. The thermionic current estimates based on the present analysis is found to be in reasonably good agreement with experimental observations (Zhu et al., Nano Res. 07, 1 (2014)). The analysis has further been simplified for the case where f-d statistics of an electron energy distribution converges to Maxwellian distribution. By using this formulation, the steady state sheath features, viz., spatial dependence of the surface potential and electron density structure in the thermionic sheath are derived and illustrated graphically for graphene parameters; the electron density in the sheath is seen to diminish within ˜10 s of Debye lengths. By utilizing the graphene based cathode in configuring a thermionic converter (TC), an appropriate operating regime in achieving the efficient energy conversion has been identified. A TC configured with the graphene based cathode (operating at ˜1200 K/work function 4.74 V) along with the metallic anode (operating at ˜400 K/ work function 2.0 V) is predicted to display ˜56% of the input thermal flux into the electrical energy, which infers approximately ˜84% of the Carnot efficiency.

Multimodal imaging in neurofibromatosis type 1-associated nerve sheath tumors; Multimodale Bildgebung bei Neurofibromatose-Typ-1-assoziierten Nervenscheidentumoren

Energy Technology Data Exchange (ETDEWEB)

Salamon, J.; Adam, G. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Diagnostic and Interventional Radiology; Mautner, V.F. [University Medical Center Hamburg-Eppendorf, Hamburg (Germany). Dept. of Neurology; Derlin, T. [Hannover Medical School, Hannover (Germany). Dept. of Nuclear Medicine

2015-12-15

Neurofibromatosis type 1 (NF1) is a neurogenetic disorder. Individuals with NF1 may develop a variety of benign and malignant tumors of which peripheral nerve sheath tumors represent the most frequent entity. Plexiform neurofibromas may demonstrate a locally destructive growth pattern, may cause severe symptoms and may undergo malignant transformation into malignant peripheral nerve sheath tumors (MPNSTs). Whole-body magnetic resonance imaging (MRI) represents the reference standard for detection of soft tissue tumors in NF1. It allows for identification of individuals with plexiform neurofibromas, for assessment of local tumor extent, and for evaluation of whole-body tumor burden on T2-weighted imaging. Multiparametric MRI may provide a comprehensive characterization of different tissue properties of peripheral nerve sheath tumors, and may identify parameters associated with malignant transformation. Due to the absence of any radiation exposure, whole-body MRI may be used for serial follow-up of individuals with plexiform neurofibromas. {sup 18}F-fluorodeoxyglucose positron-emission-tomography (FDG PET/CT) allows a highly sensitive and specific detection of MPNST, and should be used in case of potential malignant transformation of a peripheral nerve sheath tumor. PET/CT provides a sensitive whole-body tumor staging. The use of contrast-enhanced CT for diagnosis of peripheral nerve sheath tumors is limited to special indications. To obtain the most precise readings, optimized examination protocols and dedicated radiologists and nuclear medicine physicians familiar with the complex and variable morphologies of peripheral nerve sheath tumors are required.

Accuracy of small diameter sheathed thermocouples for the core flow test loop

International Nuclear Information System (INIS)

Anderson, R.L.; Kollie, T.G.

1979-04-01

This report summarizes the research and development on 0.5-mm-diameter, compacted, metal sheathed thermocouples. The objectives of this research effort have been: to identify and analyze the sources of temperature measurement errors in the use of 0.5-mm-diameter sheathed thermocouples to measure the surface temperature of the cladding of fuel-rod simulators in the Core Flow Test Loop (CFTL) at ORNL; to devise methods for reducing or correcting for these temperature measurement errors; to estimate the overall temperature measurement uncertainties; and to recommend modifications in the manufacture, installation, or materials used to minimize temperature measurement uncertainties in the CFTL experiments

Hedgehog signaling is required for formation of the notochord sheath and patterning of nuclei pulposi within the intervertebral discs.

Science.gov (United States)

Choi, Kyung-Suk; Harfe, Brian D

2011-06-07

The vertebrae notochord is a transient rod-like structure that produces secreted factors that are responsible for patterning surrounding tissues. During later mouse embryogenesis, the notochord gives rise to the middle part of the intervertebral disc, called the nucleus pulposus. Currently, very little is known about the molecular mechanisms responsible for forming the intervertebral discs. Here we demonstrate that hedgehog signaling is required for formation of the intervertebral discs. Removal of hedgehog signaling in the notochord and nearby floorplate resulted in the formation of an aberrant notochord sheath that normally surrounds this structure. In the absence of the notochord sheath, small nuclei pulposi were formed, with most notochord cells dispersed throughout the vertebral bodies during embryogenesis. Our data suggest that the formation of the notochord sheath requires hedgehog signaling and that the sheath is essential for maintaining the rod-like structure of the notochord during early embryonic development. As notochord cells form nuclei pulposi, we propose that the notochord sheath functions as a "wrapper" around the notochord to constrain these cells along the vertebral column.

Effect of radiofrequency on capacitance of low density plasma sheath

International Nuclear Information System (INIS)

Carneiro, L.T.; Cunha Rapozo, C. da

1988-01-01

It is shown that the influence of induced radiofrequency potential (V RF ) modifies the Bohm theory on ion saturation current, measured with Langmuir probes. The effect of radiofrequency potential on diode type plasma sheath resonance is also investigated. (M.C.K.)

Study on models for gap conductance between fuel and sheath for CANDU reactors

International Nuclear Information System (INIS)

Lee, K.M.; Ohn, M.Y.; Lim, H.S.; Choi, J.H.; Hwang, S.T.

1995-01-01

The gap conductance between the fuel and the sheath depends strongly on the gap width and has a significant influence on the amount of initial stored energy. The modified Ross and Stoute gap conductance model in ELESTRES is based on a simplified thermal deformation model for steady-state fuel temperature calculations. A review on a series of experiments reveals that fuel pellets crack, relocate, and are eccentrically positioned within the sheath rather than solid concentric cylinders. In this paper, the two recently-proposed gap conductance models (offset gap model and relocated gap model) are described and are applied to calculate the fuel-sheath gap conductances under experimental conditions and normal operating conditions in CANDU reactors. The good agreement between the experimentally-inferred and calculated gap conductance values demonstrates that the modified Ross and Stoute model was implemented correctly in ELESTRES. The predictions of the modified Ross and Stoute model provide conservative values for gap heat transfer and fuel surface temperature compared to the offset gap and relocated gap models for a limiting power envelope. (author)

Targeting the ECM to Enhance Drug Delivery in Nf1-Associated Nerve Sheath Tumors

Science.gov (United States)

2016-10-01

development of the principal discipline(s) of the project? • We have learned that the drug PEGPH20, which degrades a component of connective tissue called...AWARD NUMBER: W81XWH-15-1-0114 TITLE: Targeting the ECM to Enhance Drug Delivery in Nf1-Associated Nerve Sheath Tumors PRINCIPAL INVESTIGATOR...14 Sep 2016 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER NF140089 Targeting the ECM to Enhance Drug Delivery in Nf1-Associated Nerve Sheath Tumors 5b

Parallel Transport with Sheath and Collisional Effects in Global Electrostatic Turbulent Transport in FRCs

Science.gov (United States)

Bao, Jian; Lau, Calvin; Kuley, Animesh; Lin, Zhihong; Fulton, Daniel; Tajima, Toshiki; Tri Alpha Energy, Inc. Team

2017-10-01

Collisional and turbulent transport in a field reversed configuration (FRC) is studied in global particle simulation by using GTC (gyrokinetic toroidal code). The global FRC geometry is incorporated in GTC by using a field-aligned mesh in cylindrical coordinates, which enables global simulation coupling core and scrape-off layer (SOL) across the separatrix. Furthermore, fully kinetic ions are implemented in GTC to treat magnetic-null point in FRC core. Both global simulation coupling core and SOL regions and independent SOL region simulation have been carried out to study turbulence. In this work, the ``logical sheath boundary condition'' is implemented to study parallel transport in the SOL. This method helps to relax time and spatial steps without resolving electron plasma frequency and Debye length, which enables turbulent transports simulation with sheath effects. We will study collisional and turbulent SOL parallel transport with mirror geometry and sheath boundary condition in C2-W divertor.

Density and velocity measurements of a sheath plasma from MPD thruster

Energy Technology Data Exchange (ETDEWEB)

Ko, J.J.; Cho, T.S.; Choi, M.C.; Choi, E.H.; Cho, G.S.; Uhm, H.S.

1999-07-01

Magnetoplasma is the plasma that the electron and ion orbits are strongly confined by intense magnetic field. Recently, magnetoplasma dynamics (MPD) has been investigated in connection with applications to the rocket thruster in USA, Germany, etc. It can be widely applicable, including modification of satellite position and propulsion of the interplanetary space shuttle. A travel for a long distance journey is possible because a little amount of neutral gases is needed for the plasma source. Besides, this will provide a pollution free engine for future generations. MPD thruster is not a chemical engine. The authors have built a Mather type MPD thruster, which has 1 kV max charging, 10 kA max current flows, and has about 1 ms characteristic operation time. The Paschen curve of this thruster is measured and its minimum breakdown voltage occurs in the pressure range of 0.1 to 1 Torr. Langmuir and double probes are fabricated to diagnose the sheath plasma from the thruster. The temperature and density are calculated to be 2.5 eV and 10{sup 15} cm {sup {minus}3}, respectively, from the probe data. Making use of photo diode, an optical probe is fabricated to measure propagation velocity of the sheath plasma. The sheath plasma from the MPD thruster in the experiment propagates with velocity of 1 cm/{micro}s.

Hemostatic completion of percutaneous nephrolithotomy using electrocauterization and a clear amplatz renal sheath

Directory of Open Access Journals (Sweden)

Ho Song Yu

2016-02-01

Full Text Available ABSTRACT Background and Purpose A tubeless PCNL can reduce postoperative pain, the need for analgesics, hospital stay, and postoperative urinary leakage. However, perioperative or delayed bleeding remains the primary postoperative concern. We demonstrate a simple and cost-effective method to develop a clear nephrostomy tract after completion of a tubeless PCNL. Materials and Methods Four consecutive patients with renal calculi >3cm underwent a tubeless PCNL. We used a 24 Fr nephroscope and a 24 Fr transurethral resectoscope. Intraoperative urologist-directed percutaneous renal access was performed under fluoroscopy. After calculi removal, active bleeders were identified via a clear Amplatz renal sheath. The sheath provided excellent visualization of the nephrostomy tract for the detection of bleeders and surrounding structures. Bleeders were electrocauterized using a roller barrel electrode. During extraction of the renal sheath, the surgeon can confirm hemostasis in the tract and apply intermittent suction. Results Bleeding primarily originated from the torn calyeceal mucosa and the parenchyma. Tract electrocauterization was successful. All patients had mild hematuria, which resolved within two days. The average hemoglobin decrease was 1.65g/dL (0.8-2.1 and no patients required a transfusion. No perioperative complications occurred. On postoperative day 2, the patients could ambulate without a Foley catheter. During three months of follow-up, delayed bleeding or percutaneous urine leakage did not occur. Conclusions Electrocauterization with a roller barrel electrode and a clear Amplatz renal sheath is an effective method to obtain hemostasis after completion of a PCNL. Our technique is cost-effective and readily adapted without the need for additional instruments.

Electron sheath collapse in an applied-B ion diode

International Nuclear Information System (INIS)

Grechikha, A.V.

1996-01-01

The effect of the electron sheath collapse in an applied-B ion diode due to the presence of the resistive anode plasma layer was found. This effect is more damaging at higher diode voltages and may be responsible for the parasitic load effect observed in the experiments. (author). 4 figs., 2 refs

Electron sheath collapse in an applied-B ion diode

Energy Technology Data Exchange (ETDEWEB)

Grechikha, A V [Forschungszentrum Karlsruhe (Germany). Institut fuer Neutronenphysik und Reaktortechnik

1997-12-31

The effect of the electron sheath collapse in an applied-B ion diode due to the presence of the resistive anode plasma layer was found. This effect is more damaging at higher diode voltages and may be responsible for the parasitic load effect observed in the experiments. (author). 4 figs., 2 refs.

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

Energy Technology Data Exchange (ETDEWEB)

Auluck, S. K. H., E-mail: skhauluck@gmail.com, E-mail: skauluck@barc.gov.in [Physics Group, Bhabha Atomic Research Center, Mumbai (India)

2014-09-15

Experimental data compiled over five decades of dense plasma focus research are consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and “wind pressure” resisting its motion. The resulting sheath velocity, or the numerically proportional “drive parameter,” is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum, and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance.

Bounds imposed on the sheath velocity of a dense plasma focus by conservation laws and ionization stability condition

International Nuclear Information System (INIS)

Auluck, S. K. H.

2014-01-01

Experimental data compiled over five decades of dense plasma focus research are consistent with the snowplow model of sheath propagation, based on the hypothetical balance between magnetic pressure driving the plasma into neutral gas ahead and “wind pressure” resisting its motion. The resulting sheath velocity, or the numerically proportional “drive parameter,” is known to be approximately constant for devices optimized for neutron production over 8 decades of capacitor bank energy. This paper shows that the validity of the snowplow hypothesis, with some correction, as well as the non-dependence of sheath velocity on device parameters, have their roots in local conservation laws for mass, momentum, and energy coupled with the ionization stability condition. Both upper and lower bounds on sheath velocity are shown to be related to material constants of the working gas and independent of the device geometry and capacitor bank impedance

Spine Patterning Is Guided by Segmentation of the Notochord Sheath

NARCIS (Netherlands)

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

2018-01-01

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

Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

Science.gov (United States)

2016-10-26

the floating potential of wall material samples immersed in a low-temperature plasma were studied. Hysteresis is found to be due to secondary electron...continued research into plasma sheath physics. Hysteresis effects observed in the floating potential of wall material samples immersed in a low... Journal of Applied Physics, Volume 119, March 2016, pp. 113305 1-5. DISTRIBUTION A: Distribution approved for public release. 8 Figure 2

Theory of a wall sheath in a gas-discharge plasma

International Nuclear Information System (INIS)

Dvinin, S.A.; Dovzhenko, V.A.; Kuzovnikov, A.A.

1999-01-01

An integro-differential equation is proposed that generalizes the plasma-sheath (Langmuir-Tonks) equation to include charge exchange between ions and neutrals in a discharge plasma and makes it possible to correctly analyze how the discharge evolves from the regime of collisionless ion motion to the diffusive regime in pure gases with allowance for the space charge in the sheath at the plasma boundary. The integro-differential equation is solved numerically, and the ionization rate is calculated as a function of the ratio between the ion mean free path and the characteristic discharge dimension. The ion energy distribution function in the positive column of a discharge plasma is computed. The parameter range in which the positive column can exist is examined, and the limits of applicability of different discharge models are analyzed depending on the relations between the ion mean free path, Debye length, and discharge dimension

Child–Langmuir law applicability for a cathode sheath description of glow discharge in hydrogen

International Nuclear Information System (INIS)

Lisovskiy, V A; Artushenko, K P; Yegorenkov, V D

2016-01-01

The present paper reveals that the Child-Langmuir law version with the constant ion mobility has to be applied for the cathode sheath description of the glow discharge in hydrogen. Using the analytical model we demonstrate that even in a high electric field the constant mobility law version rather than that for the constant ion mean free path has to hold in the case of impeded charge exchange and the dominant effect of polarization forces on the ion motion through the cathode sheath. (paper)

Malignant Peripheral Nerve Sheath Tumor: MRI and CT Findings

Directory of Open Access Journals (Sweden)

K. O. Kragha

2015-01-01

important in its diagnosis. A rare case of MPNST that produced urinary retention and bowel incontinence is presented that may aid clinicians in the diagnosis of this rare clinical entity. Motor weakness, central enhancement, and immunohistochemistry may assist in the diagnosis of MPNST and differentiation between benign peripheral nerve sheath tumor (BPNST and MPNST.

Annihilation model of the Tormac sheath

International Nuclear Information System (INIS)

Hammer, J.H.

1979-02-01

A one-dimensional, steady state fluid model is developed to describe the boundary layer between plasma and magnetic field that occurs in the Tormac sheath. Similar systems which may be treatable by the same model are tokamaks with divertors and reversed field mirrors. The model includes transport across the magnetic field as well as mirror losses along the field, the latter being represented as annihilation terms in the one-dimensional equations. The model equations are derived from the two-dimensional, time dependent hierarchy of equations generated by taking velocity moments of the kinetic equation including collisions

Collision-dominated dust sheaths and voids - observations in micro-gravity experiments and numerical investigation of the force balance relations

International Nuclear Information System (INIS)

Tsytovich, V N; Morfill, G; Konopka, U; Thomas, H

2003-01-01

Numerical solutions of stationary force balance equations are used to investigate the possible dust configurations (dust structures) in complex plasmas between two floating potential plane electrodes. The distance between electrodes is assumed to be larger than the ion-neutral mean free path and the hydrodynamic description is used. It includes the known forces operating in this limit, the ionization source and the dust charge variations. The stationary balance equations are solved both in the case of the presence of one-size dust grains and for the case of a mixture of grains with two different sizes. Recent micro-gravity experiments with single-size dust grains and two-different-size dust grains show the formation of a system of dust sheaths and dust voids between the two plane electrodes. The observed configurations of dust structures depend strongly on the gas pressure and the degree of ionization used. The numerical investigations are able to show the necessary conditions for the types of structure to be created and give their size. The size of the structures observed is larger than the ion-neutral mean free path and is of the order of magnitude of that obtained numerically. The numerical investigations give details of the spatial distributions, the dust particles, the electron/ion densities, the ion drift velocity and dust charges inside and outside different dust structures. These details have not yet been investigated experimentally and can indicate directions for further experimental work to be performed. The single-dust-sheath structure with single-size dust particles surrounded by dust free regions (dust wall-voids) and floating potential electrodes is computed. Such a structure was observed recently and the computational results are in agreement with observations. It is shown that more often a dust void in the centre is observed. It is found that a dust void in the centre region between two electrodes is formed if the ionization rate is larger than the

Genetic instability in nerve sheath cell tumors

DEFF Research Database (Denmark)

Rogatto, Silvia Regina; Casartelli, Cacilda; Rainho, Claudia Aparecida

1995-01-01

After in vitro culture, we analyzed cytogenetically four acoustic nerve neurinomas, one intraspinal neurinoma and one neurofibroma obtainedfrom unrelated patients. Monosomy of chromosomes 22 and 16 was an abnormality common to all cases, followed in frequency by loss of chromosomes 18 (three cases...... by the presence of polyploid cells with inconsistent abnormalities, endoreduplications and telomeric associations resulting in dicentric chromosomes. It is probable that these cytogenetic abnormalities represent some kind of evolutionary advantage for the in vitro progression of nerve sheath tumors....

Particle flows to shape and voltage surface discontinuities in the electron sheath surrounding a high voltage solar array in LEO

Science.gov (United States)

Metz, Roger N.

1991-01-01

This paper discusses the numerical modeling of electron flows from the sheath surrounding high positively biased objects in LEO (Low Earth Orbit) to regions of voltage or shape discontinuity on the biased surfaces. The sheath equations are derived from the Two-fluid, Warm Plasma Model. An equipotential corner and a plane containing strips of alternating voltage bias are treated in two dimensions. A self-consistent field solution of the sheath equations is outlined and is pursued through one cycle. The electron density field is determined by numerical solution of Poisson's equation for the electrostatic potential in the sheath using the NASCAP-LEO relation between electrostatic potential and charge density. Electron flows are calculated numerically from the electron continuity equation. Magnetic field effects are not treated.

Accuracy and complications of CT-guided core needle biopsy of peripheral nerve sheath tumours

Energy Technology Data Exchange (ETDEWEB)

Pianta, Marcus; Chock, Eric; Schlicht, Stephen [St Vincent' s Hospital, Fitzroy, VIC (Australia); McCombe, David [St Vincent' s Hospital and Victorian Hand Surgery Associates, Victoria (Australia)

2015-09-15

This single-centre study retrospectively reviews the complications in patients that have occurred following peripheral nerve sheath tumour biopsy, and assesses whether there is an association with biopsy technique or underlying lesion characteristics. 41 consecutive core needle biopsies of proven peripheral nerve sheath tumours over a 2-year period in a tertiary teaching hospital were reviewed. Patient demographics and symptoms, tumour characteristics and radiological appearances were recorded. Biopsy and surgical histology were correlated, and post-biopsy and surgical complications analyzed. 41 biopsies were performed in 38 patients. 68 % schwannomas, 24 % neurofibromas and 7 % malignant peripheral nerve sheath tumours. Biopsy histology correlated with surgery in all cases. 71 % of lesions were surgically excised. 60 % of patients reported pain related to their lesion. Following the biopsy, 12 % reported increased pain, which resolved in all cases. Pain exacerbation was noted in tumours smaller in size, more superficial and in closer proximity of the biopsy needle tip to the traversing nerve. Number of biopsy needle passes was not associated with an increased incidence of procedure-related pain. Core biopsy of a suspected peripheral nerve sheath tumour may be performed safely before excisional surgery to confirm lesion histology and assist prognosis. There is excellent correlation between core biopsy and excised surgical specimen histology. The most common complication of pain exacerbation is seen in a minority and is temporary, and more likely with smaller, more superficial lesions and a closer needle-tip to traversing nerve distance during biopsy. (orig.)

Accuracy and complications of CT-guided core needle biopsy of peripheral nerve sheath tumours

International Nuclear Information System (INIS)

Pianta, Marcus; Chock, Eric; Schlicht, Stephen; McCombe, David

2015-01-01

This single-centre study retrospectively reviews the complications in patients that have occurred following peripheral nerve sheath tumour biopsy, and assesses whether there is an association with biopsy technique or underlying lesion characteristics. 41 consecutive core needle biopsies of proven peripheral nerve sheath tumours over a 2-year period in a tertiary teaching hospital were reviewed. Patient demographics and symptoms, tumour characteristics and radiological appearances were recorded. Biopsy and surgical histology were correlated, and post-biopsy and surgical complications analyzed. 41 biopsies were performed in 38 patients. 68 % schwannomas, 24 % neurofibromas and 7 % malignant peripheral nerve sheath tumours. Biopsy histology correlated with surgery in all cases. 71 % of lesions were surgically excised. 60 % of patients reported pain related to their lesion. Following the biopsy, 12 % reported increased pain, which resolved in all cases. Pain exacerbation was noted in tumours smaller in size, more superficial and in closer proximity of the biopsy needle tip to the traversing nerve. Number of biopsy needle passes was not associated with an increased incidence of procedure-related pain. Core biopsy of a suspected peripheral nerve sheath tumour may be performed safely before excisional surgery to confirm lesion histology and assist prognosis. There is excellent correlation between core biopsy and excised surgical specimen histology. The most common complication of pain exacerbation is seen in a minority and is temporary, and more likely with smaller, more superficial lesions and a closer needle-tip to traversing nerve distance during biopsy. (orig.)

Plasma-Sheath Instability in Hall Thrusters Due to Periodic Modulation of the Energy of Secondary Electrons in Cyclotron Motion

International Nuclear Information System (INIS)

Sydorenko, D.; Smolyakov, A.; Kaganovich, I.; Raitses, Y.

2008-01-01

Particle-in-cell simulation of Hall thruster plasmas reveals a plasma-sheath instability manifesting itself as a rearrangement of the plasma sheath near the thruster channel walls accompanied by a sudden change of many discharge parameters. The instability develops when the sheath current as a function of the sheath voltage is in the negative conductivity regime. The major part of the sheath current is produced by beams of secondary electrons counter-streaming between the walls. The negative conductivity is the result of nonlinear dependence of beam-induced secondary electron emission on the plasma potential. The intensity of such emission is defined by the beam energy. The energy of the beam in crossed axial electric and radial magnetic fields is a quasi-periodical function of the phase of cyclotron rotation, which depends on the radial profile of the potential and the thruster channel width. There is a discrete set of stability intervals determined by the final phase of the cyclotron rotation of secondary electrons. As a result, a small variation of the thruster channel width may result in abrupt changes of plasma parameters if the plasma state jumps from one stability interval to another

Measurements of the asymmetric dynamic sheath around a pulse biased sphere immersed in flowing metal plasma

Science.gov (United States)

Wu, Hongchen; Anders, André

2008-08-01

A long-probe technique was utilized to record the expansion and retreat of the dynamic sheath around a spherical substrate immersed in pulsed cathode arc metal plasma. Positively biased, long cylindrical probes were placed on the side and downstream of a negatively pulsed biased stainless steel sphere of 1 in. (25.4 mm) diameter. The amplitude and width of the negative high voltage pulses (HVPs) were 2 kV, 5 kV, 10 kV, and 2 µs, 4 µs, 10 µs, respectively. The variation of the probe (electron) current during the HVP is a direct measure for the sheath expansion and retreat. Maximum sheath sizes were determined for the different parameters of the HVP. The expected rarefaction zone behind the biased sphere (wake) due to the fast plasma flow was clearly established and quantified.

Photovoltaic sheathing element with one or more tabs

Energy Technology Data Exchange (ETDEWEB)

Keenihan, James R; Langmaid, Joseph A; Lopez, Leonardo C.

2017-02-07

The present invention is premised upon an assembly that includes at least a photovoltaic sheathing element capable of being affixed on a building structure. The shingle including at least a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly. Wherein the body portion includes one or more top peripheral tabs each capable of fitting under one or more vertically adjoining devices.

Narrow, duplicated internal auditory canal

Energy Technology Data Exchange (ETDEWEB)

Ferreira, T. [Servico de Neurorradiologia, Hospital Garcia de Orta, Avenida Torrado da Silva, 2801-951, Almada (Portugal); Shayestehfar, B. [Department of Radiology, UCLA Oliveview School of Medicine, Los Angeles, California (United States); Lufkin, R. [Department of Radiology, UCLA School of Medicine, Los Angeles, California (United States)

2003-05-01

A narrow internal auditory canal (IAC) constitutes a relative contraindication to cochlear implantation because it is associated with aplasia or hypoplasia of the vestibulocochlear nerve or its cochlear branch. We report an unusual case of a narrow, duplicated IAC, divided by a bony septum into a superior relatively large portion and an inferior stenotic portion, in which we could identify only the facial nerve. This case adds support to the association between a narrow IAC and aplasia or hypoplasia of the vestibulocochlear nerve. The normal facial nerve argues against the hypothesis that the narrow IAC is the result of a primary bony defect which inhibits the growth of the vestibulocochlear nerve. (orig.)

Flooding correlations in narrow channel

International Nuclear Information System (INIS)

Kim, S. H.; Baek, W. P.; Chang, S. H.

1999-01-01

Heat transfer in narrow gap is considered as important phenomena in severe accidents in nuclear power plants. Also in heat removal of electric chip. Critical heat flux(CHF) in narrow gap limits the maximum heat transfer rate in narrow channel. In case of closed bottom channel, flooding limited CHF occurrence is observed. Flooding correlations will be helpful to predict the CHF in closed bottom channel. In present study, flooding data for narrow channel geometry were collected and the work to recognize the effect of the span, w and gap size, s were performed. And new flooding correlations were suggested for high-aspect-ratio geometry. Also, flooding correlation was applied to flooding limited CHF data

Retroperitoneal Malignant Peripheral Nerve Sheath Tumour: A Rare Case Report.

Science.gov (United States)

Deger, Ayse Nur; Bayar, Mehmet Akif; Caydere, Muzaffer; Deger, Hakki; Tayfur, Mahir

2015-09-01

Malignant nerve sheath tumours (MPNST) are rare neoplasias and retroperitoneal cases are fairly rare and clinically difficult to be detected, but they are very agressive neoplasias. MPNST are frequently seen in head, neck and upper extremities. In patients with NF1; MPNST, a poor-prognostic lesion, may result from a malignant degeneration of a former plexiform neurofibroma. It is necessary to be aware of a potential malignancy in patients diagnosed with plexiform neurofibroma. We present a 21-year-old female with a diagnosis of MPNST. The patient was admited to the hospital because of a tumour in the subcutaneous region on her left buttock. The surgeon's clinical diagnosis was lipoma. After the pathological examination of biopsy specimen, the lesion was identified as "plexiform neurofibroma" and then the patient was diagnosed with Neurofibromatosis Type 1 (NF1). Simultaneously, another mass on the retroperitoneal region was identified as malignant peripheral nerve sheath tumour (MPNST).

Cilia-like structures anchor the amphioxus notochord to its sheath.

Science.gov (United States)

Bočina, Ivana; Ljubešić, Nikola; Saraga-Babić, Mirna

2011-01-01

Body stiffness is important during undulatory locomotion in fish. In amphioxus, the myosepta play an important role in transmission of muscular forces to the notochord. In order to define the specific supporting role of the notochord in amphioxus during locomotion, the ultrastructure of 10 adult amphioxus specimens was analyzed using transmission electron microscopy. Numerous cilia-like structures were found on the surface of each notochordal cell at the sites of their attachment to the notochordal sheath. Ultrastructurally, these structures consisted of the characteristic arrangement of peripheral and central microtubular doublets and were anchored to the inner layer of the notochordal sheath. Immunohistochemically, a positive reaction to applied dynein and β-tubulin antibodies characterized the area of the cilia-like structures. We propose that reduced back-and-forth movements of the cilia-like structures might contribute to the flow of the fluid content inside the notochord, thus modulating the stiffness of the amphioxus body during its undulatory locomotion. Copyright © 2009 Elsevier GmbH. All rights reserved.

Sheath formation and extraction of ions from a constricted R.F ion source

Energy Technology Data Exchange (ETDEWEB)

Abdel-Salam, F W; Helal, A G; El-Khabeary, H; El-Merai, N T [Accelerators Dept., Nuclear Research Center, Atomic Energy Authority, Cairo, (Egypt)

1997-12-31

The present work investigates the plasma characteristics in a constricted R. F. ion source. The extraction of ions from the plasma boundary and sheath formation were studied. The ion source physical parameters are discussed in order to understand the physical processes occurring within the discharge region up to the extraction system. Electron temperature and density were determined using Langmuir probe. The probe current-voltage characteristics were measured for different extraction voltages (ext.) = 0,500,1000, and 1250 volt at various constant R.F. powers. The effect of R.F. power on electron temperature was deduced for a beam = plasma discharge. This revealed that for a quasi-neutral (plasma) region the electron temperature increased linearly with the R.F. Power which leads to substantial electron heating and efficient electron energy transport in this region. Applying extraction voltage, the electron temperature drops as the ionization rate increases. The sheath thickness was obtained at constant extraction voltages. The curves show that if the ion current density increased, the sheath thickness decreased while it increases by increasing extraction voltage, and it is negligible in the plasma region. 13 figs.

Sheath-flow electrochemical detection of amino acids with a copper wire electrode in capillary electrophoresis.

Science.gov (United States)

Inoue, Junji; Kaneta, Takashi; Imasaka, Totaro

2012-09-01

Here, we report the detection of native amino acids using a sheath-flow electrochemical detector with a working electrode made of copper wire. A separation capillary that was inserted into a platinum tube in the detector acted as a grounded electrode for electrophoresis and as a flow channel for sheath liquid. Sheath liquid flowed outside the capillary to support the transport of the separated analytes to the working electrode for electrochemical detection. The copper wire electrode was aligned at the outlet of the capillary in a wall-jet configuration. Amino acids injected into the capillary were separated following elution from the end of the capillary and detection by the copper electrode. Three kinds of copper electrodes with different diameters-50, 125, and 300 μm-were examined to investigate the effect of the electrode diameter on sensitivity. The peak widths of the analytes were independent of the diameter of the working electrode, while the 300-μm electrode led to a decrease in the signal-to-noise ratio compared with the 50- and 125-μm electrodes, which showed no significant difference. The flow rate of the sheath liquid was also varied to optimize the detection conditions. The limits of detection for amino acids ranged from 4.4 to 27 μM under optimal conditions. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

ICRF antenna Faraday shield plasma sheath model

International Nuclear Information System (INIS)

Whealton, J.H.; Ryan, P.M.; Raridon, R.J.

1990-01-01

A two-dimensional nonlinear formulation that explicitly considers the plasma edge near a Faraday shield in a self-consistent manner is used in the modeling of the ion motion for a Faraday shield concept and model suggested by Perkins. Two models are considered that may provide significant insight into the generation of impurities for ion cyclotron resonance heating (ICRH) antennas. In one of these models a significant sheath periodically forms next to the Faraday screen, with ion acoustic waves heating the ions in the plasma. (orig.)

Incidence of enhancement of the optic nerve/sheath complex in fat-suppression orbit MRI

Energy Technology Data Exchange (ETDEWEB)

Lee, Ho Kyu; Yoon, Kwon Ha; Choi, Choong Gon; Suh, Dae Chul [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

1995-04-15

To elucidate the incidence of Gd-DTPA enhancement of the optic nerve/sheath complex (ONC) in patients with various ophthalmopathies using fat-suppression MRI. Orbit MRI with fat-suppression technique (ChemSat) was performed in 58 patients with normal and various orbital lesions. The fat-suppression MR was done with and without Gd-DTPA injection in all cases. MR findings were reviewed retrospectively in a blind fashion with respect to presence or absence of contrast enhancement of the ONC. Contrast enhancement of the ONC was seen in 86% (6/7) of cavernous sinus lesions, 80% (8/10) of intraconal lesions excluding the ONC, 57% (16/28) of ONC lesions, 38% (3/8) of ocular lesions, and 2% (1/55) of normal orbits. The ONC enhancement was the most common in optic nerve/sheath tumors (10/10), and pseudotumors (6/6), cavernous sinus dural arteriovenous malformations (3/3) and cavernous sinus thrombosis (2/2), and less frequently seen in optic neuritis (3/14). Enhancement of the ONC may be seen in lesions of the cavernous sinus and orbit other than optic nerve/sheath lesion.

The study of sheath flow dark zone phenomenon in dynamic individual cells scattering measurement

Science.gov (United States)

Zhang, Lu; Zhao, Hong; Wang, Xiaopin; Zhang, Weiguang

2008-09-01

Dynamic cells scattering is one of the most efficient approaches exploring in measurements of cells size, morphology and growth states. This technique can be widely applied in real-time detection for pharmaceutical industry, food industry, liquor industry and other biological fields. A novel method named dynamic individual cells scattering measurement is designed in this paper, which can make cells pass through quartz glass measurement zone one by one with sheath flow driving force. During the experiments, an obvious phenomenon has been found which is called sheath flow dark zone phenomenon (SFDZ). Under the influence of SFDZ, sheath flow forming detection becomes very difficult. In this paper, the causes giving rise to SFDZ have been analyzed. And an improved method is put forward, in which the orifice inside the measurement zone is set as an optical system. Then the illuminating system is redesigned. In this way, almost all the illuminating light can enter orifice so that the total reflection energy decreases substantially. A comparison experiments have been done, which proves the efficiency of this redesigned optical system and its sound effects on SFDZ avoiding.

Modeling of polarization phenomena due to RF sheaths and electron beams in magnetized plasma

International Nuclear Information System (INIS)

Faudot, E.

2005-01-01

This work investigates the problematic of hot spots induced by accelerated particle fluxes in tokamaks. It is shown that the polarization due to sheaths in the edge plasma in which an electron beam at a high level of energy is injected, can reach several hundreds volts and thus extend the deposition area. The notion of obstructed sheath is introduced and explains the acceleration of energy deposition by the decreasing of the sheath potential. Then, a 2-dimensional fluid modeling of flux tubes in front of ICRF antennae allows us to calculate the rectified potentials taking into account RF polarization currents transverse to magnetic field lines. The 2-dimensional fluid code designed validates the analytical results which show that the DC rectified potential is 50% greater with polarization currents than without. Finally, the simultaneous application of an electron beam and a RF potential reveals that the potentials due to each phenomenon are additives when RF potential is much greater than beam polarization. The density depletion of polarized flux tubes in 2-dimensional PIC (particles in cells) simulations is characterized but not yet explained. (author)

A mutant of a mutant of a mutant of a ...: Irradiation of progressive radiation-induced mutants in a mutation-breeding programme with Chrysanthenum morifolium RAM

International Nuclear Information System (INIS)

Broertjes, C.; Koene, P.; Veen, J.W.H. van.

1980-01-01

Radiation-induced sports in Chrysanthemum morifolium RAM. have been reported for several years. It has become an everyday practice to produce flower-colour mutants from outstanding cross-breeding products, even before they are distributed for the commercial production of cut flowers. One of the most successful and recent examples is that of cv. Horim, of which hundreds of mutants were produced by successive use of radiation-induced mutants in the mutation-breeding programme. Over about 4 years a variety of flower-colour mutants was obtained, not only largely including the outstanding characteristics of the original cultivar but sometimes even with an appreciable improvement in quality and yield. It is expected that the latter types, the Miros group, will soon completely supersede the spontaneous or raditation-induced Horim sports and mutants and take over the leading position of the Horim group in the production of all-year-round (AYR) cut-flowers. (orig.)

Measurements of the asymmetric dynamic sheath around a pulse biased sphere immersed in flowing metal plasma

International Nuclear Information System (INIS)

Wu Hongchen; Anders, Andre

2008-01-01

A long-probe technique was utilized to record the expansion and retreat of the dynamic sheath around a spherical substrate immersed in pulsed cathode arc metal plasma. Positively biased, long cylindrical probes were placed on the side and downstream of a negatively pulsed biased stainless steel sphere of 1 in. (25.4 mm) diameter. The amplitude and width of the negative high voltage pulses (HVPs) were 2 kV, 5 kV, 10 kV, and 2 μs, 4 μs, 10 μs, respectively. The variation of the probe (electron) current during the HVP is a direct measure for the sheath expansion and retreat. Maximum sheath sizes were determined for the different parameters of the HVP. The expected rarefaction zone behind the biased sphere (wake) due to the fast plasma flow was clearly established and quantified.

Excitation of surface waves and electrostatic fields by a RF (radiofrequency systems) wave in a plasma sheath with current

International Nuclear Information System (INIS)

Gutierrez Tapia, C.

1990-01-01

It is shown in a one-dimensional model that when a current in a plasma sheath is present, the excitation of surface waves and electrostatic fields by a RF wave is possible in the sheath. This phenomena depends strongly on the joint action of Miller's and driven forces. It is also shown that the action of these forces are carried out at different characteristic times when the wave front travels through the plasma sheath. The influence of the current, in the steady limit, is taken into account by a small functional variation of the density perturbations and generated electrostatic field. (Author)

Charge of a macroscopic particle in a plasma sheath

International Nuclear Information System (INIS)

Samarian, A.A.; Vladimirov, S.V.

2003-01-01

Charging of a macroscopic body levitating in a rf plasma sheath is studied experimentally and theoretically. The nonlinear charge vs size dependence is obtained. The observed nonlinearity is explained on the basis of an approach taking into account different plasma conditions for the levitation positions of different particles. The importance of suprathermal electrons' contribution to the charging process is demonstrated

Interaction of magnetized electrons with a boundary sheath: investigation of a specular reflection model

Science.gov (United States)

Krüger, Dennis; Brinkmann, Ralf Peter

2017-11-01

This publication reports analytical and numerical results concerning the interaction of gyrating electrons with a plasma boundary sheath, with focus on partially magnetized technological plasmas. It is assumed that the electron Debye length {λ }{{D}} is much smaller than the electron gyroradius {r}{{L}}, and {r}{{L}} in turn much smaller than the mean free path λ and the gradient length L of the fields. Focusing on the scale of the gyroradius, the sheath is assumed as infinitesimally thin ({λ }{{D}}\\to 0), collisions are neglected (λ \\to ∞ ), the magnetic field is taken as homogeneous, and electric fields (=potential gradients) in the bulk are neglected (L\\to ∞ ). The interaction of an electron with the electric field of the plasma boundary sheath is represented by a specular reflection {v}\\to {v}-2{v}\\cdot {{e}}z {{e}}z of the velocity {v} at the plane z = 0 of a naturally oriented Cartesian coordinate system (x,y,z). The electron trajectory is then given as sequences of helical sections, with the kinetic energy ɛ and the canonical momenta p x and p y conserved, but not the position of the axis (base point {{R}}0), the slope (pitch angle χ), and the phase (gyrophase φ). A ‘virtual interaction’ which directly maps the incoming electrons to the outgoing ones is introduced and studied in dependence of the angle γ between the field and the sheath normal {{e}}z. The corresponding scattering operator is constructed, mathematically characterized, and given as an infinite matrix. An equivalent boundary condition for a transformed kinetic model is derived.

Structural characterization of the human cerebral myelin sheath by small angle x-ray scattering

International Nuclear Information System (INIS)

De Felici, M; Felici, R; Ferrero, C; Tartari, A; Gambaccini, M; Finet, S

2008-01-01

Myelin is a multi-lamellar membrane surrounding neuronal axons and increasing their conduction velocity. When investigated by small-angle x-ray scattering (SAXS), the lamellar quasi-periodical arrangement of the myelin sheath gives rise to distinct peaks, which allow the determination of its molecular organization and the dimensions of its substructures. In this study we report on the myelin sheath structural determination carried out on a set of human brain tissue samples coming from surgical biopsies of two patients: a man around 60 and a woman nearly 90 years old. The samples were extracted either from white or grey cerebral matter and did not undergo any manipulation or chemical-physical treatment, which could possibly have altered their structure, except dipping them into a formalin solution for their conservation. Analysis of the scattered intensity from white matter of intact human cerebral tissue allowed the evaluation not only of the myelin sheath periodicity but also of its electronic charge density profile. In particular, the thicknesses of the cytoplasm and extracellular regions were established, as well as those of the hydrophilic polar heads and hydrophobic tails of the lipid bilayer. SAXS patterns were measured at several locations on each sample in order to establish the statistical variations of the structural parameters within a single sample and among different samples. This work demonstrates that a detailed structural analysis of the myelin sheath can also be carried out in randomly oriented samples of intact human white matter, which is of importance for studying the aetiology and evolution of the central nervous system pathologies inducing myelin degeneration.

Cyst(e)ine Is the Transport Metabolite of Assimilated Sulfur from Bundle-Sheath to Mesophyll Cells in Maize Leaves1

Science.gov (United States)

Burgener, Marta; Suter, Marianne; Jones, Stephanie; Brunold, Christian

1998-01-01

The intercellular distribution of the enzymes and metabolites of assimilatory sulfate reduction and glutathione synthesis was analyzed in maize (Zea mays L. cv LG 9) leaves. Mesophyll cells and strands of bundle-sheath cells from second leaves of 11-d-old maize seedlings were obtained by two different mechanical-isolation methods. Cross-contamination of cell preparations was determined using ribulose bisphosphate carboxylase (EC 4.1.1.39) and nitrate reductase (EC 1.6.6.1) as marker enzymes for bundle-sheath and mesophyll cells, respectively. ATP sulfurylase (EC 2.7.7.4) and adenosine 5′-phosphosulfate sulfotransferase activities were detected almost exclusively in the bundle-sheath cells, whereas GSH synthetase (EC 6.3.2.3) and cyst(e)ine, γ-glutamylcysteine, and glutathione were located predominantly in the mesophyll cells. Feeding experiments using [35S]sulfate with intact leaves indicated that cyst(e)ine was the transport metabolite of reduced sulfur from bundle-sheath to mesophyll cells. This result was corroborated by tracer experiments, which showed that isolated bundle-sheath strands fed with [35S]sulfate secreted radioactive cyst(e)ine as the sole thiol into the resuspending medium. The results presented in this paper show that assimilatory sulfate reduction is restricted to the bundle-sheath cells, whereas the formation of glutathione takes place predominantly in the mesophyll cells, with cyst(e)ine functioning as a transport metabolite between the two cell types. PMID:9536048

Electric field measurements in the sheath of an argon RF discharge by probing with microparticles under varying gravity conditions

NARCIS (Netherlands)

Beckers, J.; Stoffels, W.W.; Kroesen, G.M.W.; Ockenga, T.; Wolter, M.; Kersten, H.

2010-01-01

The electric field profile in the plasma sheath of an argon rf plasma has been determined by measuring the equilibrium height and the resonance frequency of plasma-confined microparticles. In order to determine the electric field structure at any position in the plasma sheath without the discharge

Moisture performance properties of exterior sheathing products made of spruce plywood or OSB

Energy Technology Data Exchange (ETDEWEB)

Ojanen, T.; Ahonen, J. [VTT Building and Transport, Espoo (Finland)

2005-02-01

Plywood and OSB (Oriented Strand Board) are building boards that are made of timber and glue and that have good structural strength. OSB is a relatively new product that is produced from various timber materials and even some wastewood can be used as raw material for this product. Due to the easy access of raw material and economical reasons, the use of OSB has been highly increasing. The moisture safety of the building envelope depends on the properties of the building products. The moisture performance properties of the sheathing boards have not got enough attention, too often these wood based materials are equated without considering the real properties and their effect on the overall moisture performance. This research was carried out to experimentally determine the material properties and performance characteristics that have an effect on the moisture performance of building structures where OSB or spruce plywood are applied as exterior sheathing boards. A relatively representative amount of samples were used to study the moisture properties of European OSB and plywood products and a comparison to one Canadian OSB and one plywood product was done. All the products used in this research were meant to be used also as exterior sheathing boards. The results shows clearly the differences between OSB and plywood products. The products are not interchangeable. The main differences can be found from the vapour permeability levels that have an effect on the drying efficiency of building structures. The products have different performance criteria, and the climate conditions and moisture loads have to be studied to evaluate their suitability and moisture safety aspects in different applications. Water repellent features and drying efficiency are somewhat opposite properties of the products and the dimensional changes under varying moisture contents can set some boundary conditions when the optimum solution for the exterior sheathing is considered. (orig.)

Simulation of a two-dimensional sheath over a flat insulator-conductor interface on a radio-frequency biased electrode in a high-density plasma

International Nuclear Information System (INIS)

Kim, Doosik; Economou, Demetre J.

2004-01-01

A combined fluid/Monte Carlo (MC) simulation was developed to study the two-dimensional (2D) sheath over a flat insulator/conductor interface on a radio-frequency (rf) biased electrode in a high-density plasma. The insulator capacitance increased the local impedance between the plasma and the bias voltage source. Thus, for uniform ion density and electron temperature far away from the wall, the sheath potential over the insulator was only a fraction of that over the conductor, resulting in a thinner sheath over the insulator. The fluid model provided the spatiotemporal profiles of the 2D sheath electric field. These were used as input to the MC simulation to compute the ion energy distribution (IED) and ion angular distribution (IAD) at different locations on the surface. The ion flux, IED, and IAD changed drastically across the insulator/conductor interface due to the diverging rf electric field in the distorted sheath. The ion flux was larger on the conductor at the expense of that on the insulator. Both the ion impact angle and angular spread increased progressively as the material interface was approached. The ion impact energy and energy spread were smaller on the insulator as compared to the conductor. For given plasma parameters, as the insulator thickness was increased, the sheath potential and thickness over the insulator decreased, and sheath distortion became more pronounced

Retroperitoneal Malignant Peripheral Nerve Sheath Tumor Replacing an Absent Kidney in a Child

Directory of Open Access Journals (Sweden)

Samin Alavi

2013-01-01

Full Text Available Malignant peripheral nerve sheath tumors (MPNSTs are nonrhabdomyosarcoma soft tissue sarcomas with rare occurrence in children specially in the retroperitoneum. We describe a young child who presented with an abdominal mass. Both ultrasound and computed tomography revealed a large right-sided abdominal mass in the anatomic place of right kidney, while no kidney or ureter was observed at that side. He underwent surgical resection of the tumor with a primary impression of Wilms tumor. To the authors’ knowledge, this is the first case of retroperitoneal malignant peripheral nerve sheath tumor and absent kidney. This case suggests the very rare probability of association of MPNSTs in children with genitourinary tract anomalies such as renal agenesis.

Dural ectasia of the optic nerve sheath: is it always benign?

Directory of Open Access Journals (Sweden)

Berker Bakbak

2009-11-01

Full Text Available Berker Bakbak1, Hava Dönmez2, Tülay Kansu3, Hayyam Kiratli41Hacettepe University Institute of Neurological Sciences and Psychiatry, Neuro-ophthalmology Unit, Ankara, Turkey; 2Diskapi Yildirim Beyazid Education and Research Hospital Neurology Clinic, Ankara, Turkey; 3Hacettepe University Medical Faculty, Department of Neurology, Neuro-Ophthalmology Unit, Ankara, Turkey; 4Hacettepe University Medical Faculty, Department of Ophthalmology, Ocular Oncology Unit, Ankara, TurkeyAbstract: A 36-year-old woman with a 3-month history of progressive visual loss had papilledema, dilatation of the optic nerve sheaths and normal cerebrospinal fluid pressures. She was diagnosed as dural ectasia of the optic nerve sheaths and surgical decompression was performed. In this case report, severe visual loss is described as a serious complication of this rare disease and the importance of early surgical intervention is emphasized.Keywords: optic nerve, dural ectasia, meningocele

An unusual case of cycticercosis of the tendon sheath of the tendoachilles.

Directory of Open Access Journals (Sweden)

Sharat Agarwal

2010-04-01

Full Text Available Cysticercosis is an infection by the larval stage (cystcercus cellulosae of the cestode, Taenia Solium (pork tape worm, especially in those individuals who live in the endemic areas. After gaining entry into the body, the larvae become encysted and may lie in subcutaneous tissue, striated muscle, the vitreous humor, or other tissues. We report an unusual case of cysticercosis of the the tendon sheath of the tendoachilles that presented as a swelling of the tendoachilles. Upon Fine Needle Aspiration and Cytology (FNAC that were conducted preoperatively, the possibility of villonodular synovitis was identified. However, the cysticercosis diagnosis was confirmed later after an excisional biopsy was performed. We could find no reports in the literature concerning an occurrence of cysticercosis in the tendon sheath of tendoachilles.

Collaborative Research: Understanding Ion Losses to Plasma Boundaries Sheaths and Presheaths

Energy Technology Data Exchange (ETDEWEB)

Hershkowitz, Noah [Univ. of Wisconsin, Madison, WI (United States)

2015-10-01

Sheaths are common to all bounded steady-state plasmas. This includes laboratory, industrial, fusion, and in some cases even space plasmas. They form in general to balance particle loss and maintain quasi-neutrality in plasmas. Electrons are lighter than the ions by 2000 times or more (depending on the gas), and in most plasmas ion temperatures are rarely higher than the electron temperature and generally much lower. Thus in most cases, negative potential sheaths occur to confine electrons and allow ions to be freely lost. We have investigated how a plasma locally response to a positive bias on a small electrode, and have established area criteria which plasma reacts differently to the positive bias – first a pure electron sheath, and a global non-ambipolar regime where all electrons are lost to the electrode, and a double layer structure identified as a virtual cathode forms to limiting electron loss and maintain quasi-neutrality, and finally a anode spot regime where a secondary discharge occurs in front of the electrode, turning it into the major loss area of the entire plasma. Electrode area and plasma parameters criteria for these regimes were established, and the effect of the virtual cathode on the electrode’s I-V characteristics was investigated. We have also developed a global non-ambipolar electron source to replace hollow cathodes in a number of plasma applications. This eliminates the lifetime limitation and maintenance cost of hollow cathodes as they easily wear out easily and cannot be replaced in space applications.

Fine Mapping and Cloning of Leafy Head Mutant Gene pla1-5 in Rice

Directory of Open Access Journals (Sweden)

Gong-neng FENG

2013-09-01

Full Text Available We identified a leafy head mutant pla1-5 (plastochron 1-5 from the progeny of japonica rice cultivar Taipei 309 treated with 60Co-γ ray irradiation. The pla1-5 mutant has a dwarf phenotype and small leaves. Compared with its wild type, pla1-5 has more leaves and fewer tillers, and it fails to produce normal panicles at the maturity stage. Genetic analysis showed that the pla1-5 phenotype is controlled by a single recessive nuclear gene. Using the map-based cloning strategy, we narrowed down the location of the target gene to a 58-kb region between simple sequence repeat markers CHR1027 and CHR1030 on the long arm of chromosome 10. The target gene cosegregated with molecular markers CHR1028 and CHR1029. There were five predicted genes in the mapped region. The results from sequencing analysis revealed that there was one base deletion in the first exon of LOC_Os10g26340 encoding cytochrome P450 CYP78A11 in the pla1-5 mutant, which might result in a downstream frame shift and premature termination. These results suggest that the P450 CYP78A11 gene is the candidate gene of PLA1-5.

The dust characteristics in the collisional plasma sheath at the presence of external magnetic field

Energy Technology Data Exchange (ETDEWEB)

Shourkaei, Hossein Akbarian [AEOI, Tehran (Iran, Islamic Republic of). Plasma Physics Research Group

2015-05-15

The characteristics of dust in a plasma sheath are investigated in the presence of an external magnetic field and taking into account neutral collision forces. By using the fluid model, the continuity and momentum equations of ions and dusts are solved numerically with various magnitudes of collision force. In various magnitude and directions of the magnetic field, the electron and ion density distribution, ion flow velocity, electron potential have been calculated. It is shown that magnetic field has obvious effect on the plasma sheath and the collision force reduces the dust kinetic energy.

Role of CD44 in Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis

National Research Council Canada - National Science Library

Sherman, Larry

2003-01-01

Malignant peripheral nerve sheath tumors (MPNST) are aggressive, difficult to treat tumors that occur in type I neurofibromatosis patients with an increased incidence compared to the general population...

Role of CD44 in Malignant Peripheral Nerve Sheath Tumor Growth and Metastasis

National Research Council Canada - National Science Library

Sherman, Larry

2001-01-01

Malignant peripheral nerve sheath tumors (MPNST) are aggressive, difficult to treat tumors that occur in type I neurofibromatosis patients with an increased incidence compared to the general population...

Reduction of shunt obstructions by using a peel-away sheath technique? A multicenter prospective randomized trial.

Science.gov (United States)

Kehler, Uwe; Langer, Niels; Gliemroth, Jan; Meier, Ullrich; Lemcke, Johannes; Sprung, Christian; Schlosser, Hans-Georg; Kiefer, Michael; Eymann, Regina; Heese, Oliver

2012-05-01

Shunt obstructions may partly be caused by brain debris, which intrude into the ventricular catheter during ventricle puncture. Avoiding contact between the catheter and brain tissue, by using a peel-away sheath, should reduce the number of shunt failures caused by obstruction. To test this hypothesis, we conducted a randomized, prospective multicenter study. 201 patients from 6 different neurosurgical centers in Germany receiving a ventriculo-peritoneal shunt were included in this study. Of these, 177 patients completed a 1-year follow-up period. Surgery was randomized in a 1 to 1 fashion, such that out of 177 procedures, 91 were performed using a peel-away sheath and 86 were performed without. The rate of surgical re-interventions and shunt obstructions within a 12-month period was recorded. Within 1 year post-surgery, 17 shunt obstructions (9.6%) leading to shunt revisions were recorded. However, no difference was found between surgeries performed using a peel-away sheath (9.9%) or not (9.3%). The overall shunt infection rate was 2.8% and the shunt revision rate for overdrainage was 3.9%. The theoretical advantages attributed to the use of a peel-away sheath to introduce a ventricular catheter could not be confirmed in this randomized study, suggesting that the proposed role of brain debris in shunt obstructions may be overestimated. Copyright © 2011 Elsevier B.V. All rights reserved.

The Sheath-less Planar Langmuir Probe

Science.gov (United States)

Cooke, D. L.

2017-12-01

The Langmuir probe is one of the oldest plasma diagnostics, provided the plasma density and species temperature from analysis of a current-voltage curve as the voltage is swept over a practically chosen range. The analysis depends on a knowledge or theory of the many factors that influence the current-voltage curve including, probe shape, size, nearby perturbations, and the voltage reference. For applications in Low Earth Orbit, the Planar Langmuir Probe, PLP, is an attractive geometry because the ram ion current is very constant over many Volts of a sweep, allowing the ion density and electron temperature to be determined independently with the same instrument, at different points on the sweep. However, when the physical voltage reference is itself small and electrically floating as with a small spacecraft, the spacecraft and probe system become a double probe where the current collection theory depends on the interaction of the spacecraft with the plasma which is generally not as simple as the probe itself. The Sheath-less PLP, SPLP, interlaces on a single ram facing surface, two variably biased probe elements, broken into many small and intertwined segments on a scale smaller than the plasma Debye length. The SPLP is electrically isolated from the rest of the spacecraft. For relative bias potentials of a few volts, the ion current to all segments of each element will be constant, while the electron currents will vary as a function of the element potential and the electron temperature. Because the segments are small, intertwined, and floating, the assembly will always present the same floating potential to the plasma, with minimal growth as a function of voltage, thus sheath-less and still planar. This concept has been modelled with Nascap, and tested with a physical model inserted into a Low Earth Orbit-like chamber plasma. Results will be presented.

Repair of gamma radiation damage in wild type and a radiation sensitive mutant of Deinococcus radiodurans

International Nuclear Information System (INIS)

Mizuma, Nagayo

1989-01-01

In an effort to examine production and repair of radiation-induced single and double strand breaks in the DNA, a repair-deficient wild type and a repair-deficient mutant, UV17, of Deinococcus radiodurans were subjected to Co-60 gamma irradiation at a dose rate of 6.3 kGy/hr for wild type and 3.9 kGy/hr for UV17 mutant. The shoulder of the curve of UV17 mutant was narrow but existed with the intercept of 0.7 kGy and the corresponding value of the wild type was 4.2 kGy. Mutant cells exhibited about 6 fold increases in sensitivity for the shoulder relative to the wild type. The D 37 doses in the wild type and the mutant were 0.57 kGy and 0.25 kGy, respectively. From the survival curves, difference in the sensitivity between two strains was mainly due to difference of repair capacity than the number of radiation sensitive target. Sedimentation rate of the main component in the irradiated cells of UV17 mutant increased almost to the level of unirradiated control by the postincubation at 30deg C for 3 hrs. The results indicated that this sensitive mutant also exhibited an ability to restore single strand breaks after exposure to a sublethal dose of 0.6 kGy. When restitution of double strand breaks was analyzed by sedimentation in a neutral sucrose gradient, the wild type showed restitution to DNA-membrane complex from large part of the breaks. For UV17 mutant, the apparent increase in DNA-membrane complex formation was seen after 3 hours incubation. Large part of the decrease in the activities of peak 2 was recovered in the peak 1 for the wild type. For the mutant, there was little restitution to peak 1. Almost free DNA component in UV17 mutant, therefore, was merely degraded into shorter pieces. Restoration of DNA-membrane complex from free DNA derived from gamma-ray induced double strand scission involved closely in the repair of gamma-induced damage and survival. (N.K.)

Linear electromagnetic excitation of an asymmetric low pressure capacitive discharge with unequal sheath widths

Energy Technology Data Exchange (ETDEWEB)

Lieberman, M. A., E-mail: lieber@eecs.berkeley.edu; Lichtenberg, A. J.; Kawamura, E. [Department of Electrical Engineering and Computer Science, University of California, Berkeley, California 94720-1770 (United States); Chabert, P. [Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, UPMC, Paris XI, Observatoire de Paris, 91128 Palaiseau (France)

2016-01-15

It is well-known that standing waves having radially center-high radio frequency (rf) voltage profiles exist in high frequency capacitive discharges. In this work, we determine the symmetric and antisymmetric radially propagating waves in a cylindrical capacitive discharge that is asymmetrically driven at the lower electrode by an rf voltage source. The discharge is modeled as a uniform bulk plasma which at lower frequencies has a thicker sheath at the smaller area powered electrode and a thinner sheath at the larger area grounded electrode. These are self-consistently determined at a specified density using the Child law to calculate sheath widths and the electron power balance to calculate the rf voltage. The fields and the system resonant frequencies are determined. The center-to-edge voltage ratio on the powered electrode is calculated versus frequency, and central highs are found near the resonances. The results are compared with simulations in a similar geometry using a two-dimensional hybrid fluid-analytical code, giving mainly a reasonable agreement. The analytic model may be useful for finding good operating frequencies for a given discharge geometry and power.

Use of a pressure sensing sheath: comparison with standard means of blood pressure monitoring in catheterization procedures.

Science.gov (United States)

Purdy, Phillip D; South, Charles; Klucznik, Richard P; Liu, Kenneth C; Novakovic, Robin L; Puri, Ajit S; Pride, G Lee; Aagaard-Kienitz, Beverly; Ray, Abishek; Elliott, Alan C

2017-08-01

Monitoring of blood pressure (BP) during procedures is variable, depending on multiple factors. Common methods include sphygmomanometer (BP cuff), separate radial artery catheterization, and side port monitoring of an indwelling sheath. Each means of monitoring has disadvantages, including time consumption, added risk, and signal dampening due to multiple factors. We sought an alternative approach to monitoring during procedures in the catheterization laboratory. A new technology involving a 330 µm fiberoptic sensor embedded in the wall of a sheath structure was tested against both radial artery catheter and sphygmomanometer readings obtained simultaneous with readings recorded from the pressure sensing system (PSS). Correlations and Bland-Altman analysis were used to determine whether use of the PSS could substitute for these standard techniques. The results indicated highly significant correlations in systolic, diastolic, and mean arterial pressures (MAP) when compared against radial artery catheterization (p<0.0001), and MAP means differed by <4%. Bland-Altman analysis of the data suggested that the sheath measurements can replace a separate radial artery catheter. While less striking, significant correlations were seen when PSS readings were compared against BP cuff readings. The PSS has competitive functionality to that seen with a dedicated radial artery catheter for BP monitoring and is available immediately on sheath insertion without the added risk of radial catheterization. The sensor is structurally separated from the primary sheath lumen and readings are unaffected by device introduction through the primary lumen. Time delays and potential complications from radial artery catheterization are avoided. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Effects of MgO impurities and micro-cracks on the critical current density of Ti-sheathed MgB2 wires

International Nuclear Information System (INIS)

Liang, G.; Alessandrini, M.; Yen, F.; Hanna, M.; Fang, H.; Hoyt, C.; Lv, B.; Zeng, J.; Salama, K.

2007-01-01

Ti-sheathed monocore MgB 2 wires with improved magnetic critical current density (J c ) have been fabricated by in situ powder-in-tube (PIT) method and characterized by magnetization, X-ray diffraction, scanning electron microscopy and electrical resistivity measurements. For the best wire, the magnetic J c values at 5 K and fields of 2 T, 5 T, and 8 T are 4.1 x 10 5 A/cm 2 , 7.8 x 10 4 A/cm 2 , and 1.4 x 10 4 A/cm 2 , respectively. At 20 K and fields of 0.5 T and 3 T, the J c values are about 3.6 x 10 5 A/cm 2 and 3.1 x 10 4 A/cm 2 , respectively, which are much higher than those of the Fe-sheathed mono-core MgB 2 wires fabricated with the same in situ PIT process and under the same fabricating conditions. It appears that the overall J c for the average Ti-sheathed wires is comparable to that of the Fe-sheathed wires. Our X-ray diffraction and scanning electron microscopy analysis indicates that J c in the Ti-sheathed MgB 2 wires can be strongly suppressed by MgO impurities and micro-cracks

Wilms Tumor 1b defines a wound-specific sheath cell subpopulation associated with notochord repair

Science.gov (United States)

Lopez-Baez, Juan Carlos; Zeng, Zhiqiang; Brunsdon, Hannah; Salzano, Angela; Brombin, Alessandro; Wyatt, Cameron; Rybski, Witold; Huitema, Leonie F A; Dale, Rodney M; Kawakami, Koichi; Englert, Christoph; Chandra, Tamir; Schulte-Merker, Stefan

2018-01-01

Regenerative therapy for degenerative spine disorders requires the identification of cells that can slow down and possibly reverse degenerative processes. Here, we identify an unanticipated wound-specific notochord sheath cell subpopulation that expresses Wilms Tumor (WT) 1b following injury in zebrafish. We show that localized damage leads to Wt1b expression in sheath cells, and that wt1b+cells migrate into the wound to form a stopper-like structure, likely to maintain structural integrity. Wt1b+sheath cells are distinct in expressing cartilage and vacuolar genes, and in repressing a Wt1b-p53 transcriptional programme. At the wound, wt1b+and entpd5+ cells constitute separate, tightly-associated subpopulations. Surprisingly, wt1b expression at the site of injury is maintained even into adult stages in developing vertebrae, which form in an untypical manner via a cartilage intermediate. Given that notochord cells are retained in adult intervertebral discs, the identification of novel subpopulations may have important implications for regenerative spine disorder treatments. PMID:29405914

Current sheath curvature correlation with the neon soft x-ray emission from plasma focus device

International Nuclear Information System (INIS)

Zhang, T; Lin, X; Chandra, K A; Tan, T L; Springham, S V; Patran, A; Lee, P; Lee, S; Rawat, R S

2005-01-01

The insulator sleeve length is one of the major parameters that can severely affect the neon soft x-ray yield from a plasma focus. The effect of the insulation sleeve length on various characteristic timings of plasma focus discharges and hence the soft x-ray emission characteristics has been investigated using a resistive divider. The pinhole images and laser shadowgraphy are used to explain the observed variation in the average soft x-ray yield (measured using a diode x-ray spectrometer) with variation of the insulator sleeve length. We have found that for a neon filled plasma focus device the change in insulator sleeve length changes the current sheath curvature angle and thus the length of the focused plasma column. The optimized current sheath curvature angle is found to be between 39 0 and 41 0 , at the specific axial position of 6.2-9.3 cm from the cathode support plate, for our 3.3 kJ plasma focus device. A strong dependence of the neon soft x-ray yield on the current sheath curvature angle has thus been reported

Doppler spectroscopic measurements of sheath ion velocities in radio-frequency plasmas

International Nuclear Information System (INIS)

Woodcock, B.K.; Busby, J.R.; Freegarde, T.G.; Hancock, G.

1997-01-01

We have measured the distributions of N 2 + ion velocity components parallel and perpendicular to the electrode in the sheath of a radio-frequency nitrogen reactive ion etching discharge, using pulsed laser-induced fluorescence. Parallel to the electrode, the ions have throughout a thermal distribution that is found to be consistent with the rotational temperature of 355 K. In the perpendicular direction, we see clearly the acceleration of the ions towards the electrode, and our results agree well with theoretical predictions although an unexpected peak of unaccelerated ions persists. We have also determined the absolute ion concentrations in the sheath, which we have calibrated by analyzing the decay in laser-induced fluorescence in the plasma bulk after discharge extinction. At 20 mTorr, the bulk concentration of 1.0x10 10 cm -3 falls to around 2x10 8 cm -3 at 2 mm from the electrode. copyright 1997 American Institute of Physics

Malignant transformation in a hybrid schwannoma/perineurioma: Addition to the spectrum of a malignant peripheral nerve sheath tumor

Directory of Open Access Journals (Sweden)

Bharat Rekhi

2011-01-01

Full Text Available Benign nerve sheath tumors include schwannomas, neurofibromas and perineuriomas. The malignant counterpart of a nerve sheath tumor is designated as a malignant peripheral nerve sheath tumor (MPNST. Lately, benign nerve sheath tumors comprising more than one component have been described, including hybrid schwannomas/perineuriomas. However, malignant transformation in a hybrid schwannoma/perineurioma has not been documented so far. Herein, we present a rare case of a young adult male who presented with a soft tissue mass in his right thigh that was excised elsewhere and submitted to us for histopathological review. One of the tissue sections displayed histopathological features of a hybrid schwannoma/perineurioma, including alternate arrangement of benign schwann and perineurial cells, reinforced with S100-P and epithelial membrane antigen positivity, respectively, along with low MIB1 and negative p53 immunostaining. The other two tissue sections showed a spindly sarcomatous tumor that was immunohistochemically positive for S100-P, CD34, p53 and exhibited high MIB1 (30-40%. Diagnosis of a MPNST arising in a hybrid schwannoma/perineurioma was made. This unusual case forms yet another addition to the spectrum of a MPNST.

Identification and characterization of a gibberellin-regulated protein, which is ASR5, in the basal region of rice leaf sheaths.

Science.gov (United States)

Takasaki, Hironori; Mahmood, Tariq; Matsuoka, Makoto; Matsumoto, Hiroshi; Komatsu, Setsuko

2008-04-01

Gibberellins (GAs) regulate growth and development in higher plants. To identify GA-regulated proteins during rice leaf sheath elongation, a proteomic approach was used. Proteins from the basal region of leaf sheath in rice seedling treated with GA(3) were analyzed by fluorescence two-dimensional difference gel electrophoresis. The levels of abscisic acid-stress-ripening-inducible 5 protein (ASR5), elongation factor-1 beta, translationally controlled tumor protein, fructose-bisphosphate aldolase and a novel protein increased; whereas the level of RuBisCO subunit binding-protein decreased by GA(3) treatment. ASR5 out of these six proteins was significantly regulated by GA(3) at the protein level but not at the mRNA level in the basal region of leaf sheaths. Since this protein is regulated not only by abscisic acid but also by GA(3), these results indicate that ASR5 might be involved in plant growth in addition to stress in the basal regions of leaf sheaths.

Emilin3 is required for notochord sheath integrity and interacts with Scube2 to regulate notochord-derived Hedgehog signals.

Science.gov (United States)

Corallo, Diana; Schiavinato, Alvise; Trapani, Valeria; Moro, Enrico; Argenton, Francesco; Bonaldo, Paolo

2013-11-01

The notochord is a transient and essential structure that provides both mechanical and signaling cues to the developing vertebrate embryo. In teleosts, the notochord is composed of a core of large vacuolated cells and an outer layer of cells that secrete the notochord sheath. In this work, we have identified the extracellular matrix glycoprotein Emilin3 as a novel essential component of the zebrafish notochord sheath. The development of the notochord sheath is impaired in Emilin3 knockdown embryos. The patterning activity of the notochord is also affected by Emilin3, as revealed by the increase of Hedgehog (Hh) signaling in Emilin3-depleted embryos and the decreased Hh signaling in embryos overexpressing Emilin3 in the notochord. In vitro and in vivo experiments indicate that Emilin3 modulates the availability of Hh ligands by interacting with the permissive factor Scube2 in the notochord sheath. Overall, this study reveals a new role for an EMILIN protein and reinforces the concept that structure and function of the notochord are strictly linked.

Similarities and distinctions of CIR and Sheath

Science.gov (United States)

Yermolaev, Yuri; Lodkina, Irina; Nikolaeva, Nadezhda; Yermolaev, Michael

2016-04-01

On the basis of OMNI data and our catalog of large scale solar wind (SW) streams during 1976-2000 [Yermolaev et al., 2009] we study the average temporal profiles for two types of compressed regions: CIR (corotating interaction region - compressed region before High Speed Stream (HSS)) and Sheath (compressed region before fast Interplanetary CMEs (ICMEs), including Magnetic Cloud (MC) and Ejecta). As have been shown by Nikolaeva et al, [2015], the efficiency of magnetic storm generation is ~50% higher for Sheath and CIR than for ICME (MC and Ejecta), i.e. reaction magnetosphere depends on type of driver. To take into account the different durations of SW types, we use the double superposed epoch analysis (DSEA) method: rescaling the duration of the interval for all types in such a manner that, respectively, beginning and end for all intervals of selected type coincide [Yermolaev et al., 2010; 2015]. Obtained data allows us to suggest that the formation of all types of compression regions has the same physical mechanism irrespective of piston (HSS or ICME) type and differences are connected with geometry and full jumps of speed in edges of compression regions. If making the natural assumption that the gradient of speed is directed approximately on normal to the piston, CIR has the largest angle between the gradient of speed and the direction of average SW speed, and ICME - the smallest angle. The work was supported by the Russian Foundation for Basic Research, projects 13-02-00158, 16-02-00125 and by Program of Presidium of the Russian Academy of Sciences. References: Nikolaeva, N. S. , Yu. I. Yermolaev, and I. G. Lodkina (2015), Modeling of the Corrected Dst* Index Temporal Profile on the Main Phase of the Magnetic Storms Generated by Different Types of Solar Wind, Cosmic Research, Vol. 53, No. 2, pp. 119-127. Yermolaev, Yu. I., N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev (2009), Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research

Primary optic nerve sheath meningioma

Energy Technology Data Exchange (ETDEWEB)

Jeremic, Branislav [International Atomic Energy Agency, Vienna (Austria); Pitz, Susanne (eds.) [University Eye Hospital, Mainz (Germany)

2008-07-01

Optic nerve sheath meningioma (ONSM) is a rare tumour. Cases are usually separated into primary ONSM, which arises either intraorbitally or, less commonly, intracanalicularly, and secondary ONSM, which arises intracranially and subsequently invades the optic canal and orbit. This is the first book to cover all important aspects of the diagnosis and treatment of primary ONSM. After a general introduction, individual chapters discuss the clinical presentation, clinical examination and diagnosis, imaging, and histology. Treatment options are then addressed in detail, with special emphasis on external beam radiation therapy, and in particular stereotactic fractionated radiation therapy. The latter has recently produced consistently good results and is now considered the emerging treatment of choice for the vast majority of patients with primary ONSM. This well-illustrated book will prove invaluable to all practitioners who encounter primary ONSM in their clinical work. (orig.)

Dust particle charge and screening in the collisional RF plasma sheath

NARCIS (Netherlands)

Beckers, J.; Trienekens, D.J.M.; Kroesen, G.M.W.; Sprouse, G.D.

2012-01-01

Once immersed in plasma, a dust particle gathers a highly negative charge due to the net collection of free electrons. In most plasma's on earth and with particle sizes is in the micrometer range, the gravitational force is dominant and consequently the particle ends up within the plasma sheath

Tearing mode of a neutral current sheath in a plasma flux

International Nuclear Information System (INIS)

Gubchenko, V.M.

1982-01-01

The linear stage of the tearing mode of diffusion neutral current sheath immersed in the plasma flux directed along the magnetic field is considered. It follows form the obtained dispersion characteristics that the flux exerts a stabilizing effect on the mode and leads to appearance of phase drift velocity

Measurement of electric field and gradient in the plasma sheath using clusters of floating microspheres

International Nuclear Information System (INIS)

Sheridan, T. E.; Katschke, M. R.; Wells, K. D.

2007-01-01

A method for measuring the time-averaged vertical electric field and its gradient in the plasma sheath using clusters with n=2 or 3 floating microspheres of known mass is described. The particle charge q is found by determining the ratio of the breathing frequency to the center-of-mass frequency for horizontal (in-plane) oscillations. The electric field at the position of the particles is then calculated using the measured charge-to-mass ratio, and the electric-field gradient is determined from the vertical resonance frequency. The Debye length is also found. Experimental results are in agreement with a simple sheath model

“Orphan” γ-Ray Flares and Stationary Sheaths of Blazar Jets

Science.gov (United States)

MacDonald, Nicholas R.; Jorstad, Svetlana G.; Marscher, Alan P.

2017-11-01

Blazars exhibit flares across the entire electromagnetic spectrum. Many γ-ray flares are highly correlated with flares detected at longer wavelengths; however, a small subset appears to occur in isolation, with little or no correlated variability at longer wavelengths. These “orphan” γ-ray flares challenge current models of blazar variability, most of which are unable to reproduce this type of behavior. MacDonald et al. have developed the Ring of Fire model to explain the origin of orphan γ-ray flares from within blazar jets. In this model, electrons contained within a blob of plasma moving relativistically along the spine of the jet inverse-Compton scatter synchrotron photons emanating off of a ring of shocked sheath plasma that enshrouds the jet spine. As the blob propagates through the ring, the scattering of the ring photons by the blob electrons creates an orphan γ-ray flare. This model was successfully applied to modeling a prominent orphan γ-ray flare observed in the blazar PKS 1510-089. To further support the plausibility of this model, MacDonald et al. presented a stacked radio map of PKS 1510-089 containing the polarimetric signature of a sheath of plasma surrounding the spine of the jet. In this paper, we extend our modeling and stacking techniques to a larger sample of blazars: 3C 273, 4C 71.01, 3C 279, 1055+018, CTA 102, and 3C 345, the majority of which have exhibited orphan γ-ray flares. We find that the model can successfully reproduce these flares, while our stacked maps reveal the existence of jet sheaths within these blazars.

A palladium-doped ceria@carbon core-sheath nanowire network: a promising catalyst support for alcohol electrooxidation reactions

Science.gov (United States)

Tan, Qiang; Du, Chunyu; Sun, Yongrong; Du, Lei; Yin, Geping; Gao, Yunzhi

2015-08-01

A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique interconnected one-dimensional core-sheath structure is revealed to facilitate immobilization of the metal catalysts, leading to the improved durability. This core-sheath nanowire network opens up a new strategy for catalyst performance optimization for next-generation fuel cells.A novel palladium-doped ceria and carbon core-sheath nanowire network (Pd-CeO2@C CSNWN) is synthesized by a template-free and surfactant-free solvothermal process, followed by high temperature carbonization. This hierarchical network serves as a new class of catalyst support to enhance the activity and durability of noble metal catalysts for alcohol oxidation reactions. Its supported Pd nanoparticles, Pd/(Pd-CeO2@C CSNWN), exhibit >9 fold increase in activity toward the ethanol oxidation over the state-of-the-art Pd/C catalyst, which is the highest among the reported Pd systems. Moreover, stability tests show a virtually unchanged activity after 1000 cycles. The high activity is mainly attributed to the superior oxygen-species releasing capability of Pd-doped CeO2 nanowires by accelerating the removal of the poisoning intermediate. The unique

3D Visualization of Sheath Folds in Roman Marble from Ephesus, Turkey

Science.gov (United States)

Wex, Sebastian; Passchier, Cornelis W.; de Kemp, Eric A.; Ilhan, Sinan

2013-04-01

Excavation of a palatial 2nd century AD house (Terrace House Two) in the ancient city of Ephesus, Turkey in the 1970s produced 10.313 pieces of colored, folded marble which belonged to 54 marble plates of 1.6 cm thickness that originally covered the walls of the banquet hall of the house. The marble plates were completely reassembled and restored by a team of workers over the last 6 years. The plates were recognized as having been sawn from two separate large blocks of "Cipollino verde", a green mylonitized marble from Karystos on the Island of Euboea, Greece. After restoration, it became clear that all slabs had been placed on the wall in approximately the sequence in which they had been cut off by a Roman stone saw. As a result, the marble plates give a full 3D insight in the folded internal structure of 1m3 block of mylonite. The restoration of the slabs was recognized as a first, unique opportunity for detailed reconstruction of the 3D geometry of m-scale folds in mylonitized marble. Photographs were taken of each slab and used to reconstruct their exact arrangement within the originally quarried blocks. Outlines of layers were digitized and a full 3D reconstruction of the internal structure of the block was created using ArcMap and GOCAD. Fold structures in the block include curtain folds and multilayered sheath folds. Several different layers showing these structures were digitized on the photographs of the slab surfaces and virtually mounted back together within the model of the marble block. Due to the serial sectioning into slabs, with cm-scale spacing, the visualization of the 3D geometry of sheath folds was accomplished with a resolution better than 4 cm. Final assembled 3D images reveal how sheath folds emerge from continuous layers and show their overall consistency as well as a constant hinge line orientation of the fold structures. Observations suggest that a single deformation phase was responsible for the evolution of "Cipollino verde" structures

Fast, kinetically self-consistent simulation of RF modulated plasma boundary sheaths

International Nuclear Information System (INIS)

Shihab, Mohammed; Ziegler, Dennis; Brinkmann, Ralf Peter

2012-01-01

A mathematical model is presented which enables the efficient, kinetically self-consistent simulation of RF modulated plasma boundary sheaths in all technically relevant discharge regimes. It is defined on a one-dimensional geometry where a Cartesian x-axis points from the electrode or wall at x E ≡ 0 towards the plasma bulk. An arbitrary endpoint x B is chosen ‘deep in the bulk’. The model consists of a set of kinetic equations for the ions, Boltzmann's relation for the electrons and Poisson's equation for the electrical field. Boundary conditions specify the ion flux at x B and a periodically—not necessarily harmonically—modulated sheath voltage V(t) or sheath charge Q(t). The equations are solved in a statistical sense. However, it is not the well-known particle-in-cell (PIC) scheme that is employed, but an alternative iterative algorithm termed ensemble-in-spacetime (EST). The basis of the scheme is a discretization of the spacetime, the product of the domain [x E , x B ] and the RF period [0, T]. Three modules are called in a sequence. A Monte Carlo module calculates the trajectories of a large set of ions from their start at x B until they reach the electrode at x E , utilizing the potential values on the nodes of the spatio-temporal grid. A harmonic analysis module reconstructs the Fourier modes n im (x) of the ion density n i (x, t) from the calculated trajectories. A field module finally solves the Boltzmann-Poisson equation with the calculated ion densities to generate an updated set of potential values for the spatio-temporal grid. The iteration is started with the potential values of a self-consistent fluid model and terminates when the updates become sufficiently small, i.e. when self-consistency is achieved. A subsequent post-processing determines important quantities, in particular the phase-resolved and phase-averaged values of the ion energy and angular distributions and the total energy flux at the electrode. A drastic reduction of the

Mineralized fibroma of the tendon sheath presenting as a bursitis

Energy Technology Data Exchange (ETDEWEB)

Le Corroller, Thomas; Champsaur, Pierre [Hopital Sainte-Marguerite, Service de Radiologie, Marseille (France); Faculte de Medecine de Marseille, Departement d' Anatomie, Marseille (France); Bouvier-Labit, Corinne [Hopital La Timone, Service d' Anatomopathologie, Marseille (France); Sbihi, Abderrahmane [Clinique Juge, Service de Chirurgie orthopedique, Marseille (France)

2008-12-15

We report on the clinical, imaging - including ultrasound, computed tomography, and magnetic resonance imaging - and histological features of a fibroma of the tendon sheath with mineralized chondroid and osseous metaplasia, presenting as a semimembranosus bursitis. The anatomical characteristics of the semimembranosus bursa are demonstrated by dissection in a cadaveric specimen and correlated with the imaging findings in our patient. (orig.)

Mineralized fibroma of the tendon sheath presenting as a bursitis

International Nuclear Information System (INIS)

Le Corroller, Thomas; Champsaur, Pierre; Bouvier-Labit, Corinne; Sbihi, Abderrahmane

2008-01-01

We report on the clinical, imaging - including ultrasound, computed tomography, and magnetic resonance imaging - and histological features of a fibroma of the tendon sheath with mineralized chondroid and osseous metaplasia, presenting as a semimembranosus bursitis. The anatomical characteristics of the semimembranosus bursa are demonstrated by dissection in a cadaveric specimen and correlated with the imaging findings in our patient. (orig.)

The urogenital-hypogastric sheath: an anatomical observation on the relationship between the inferomedial extension of renal fascia and the hypogastric nerves.

Science.gov (United States)

Yang, X F; Luo, G H; Ding, Z H; Li, G X; Chen, X W; Zhong, S Z

2014-11-01

The study aimed to perform an anatomical observation on the inferomedial extension of the renal fascia (RF) to the pelvis and explore its relationship with the hypogastric nerves (HGNs). Gross anatomy was performed on 12 formalin-fixed and 12 fresh cadavers. Sectional anatomy was performed on four formalin-fixed cadavers. Different from the traditional concept, both the anterior and posterior RF included the outer and inner layer with different inferomedial extensions. The multiple layers of RF extended downward to form a sandwich-like and compound fascia sheath with potential and expandable spaces which was named as "the urogenital-hypogastric sheath." Below the level of the origin of the inferior mesenteric artery, the bilateral urogenital-hypogastric sheath communicated with the counterpart in front of the great vessels in the midline and the superior hypogastric plexus ran into the urogenital-hypogastric sheath which carried the HGNs, ureters, and genital vessels downward to their terminations in the pelvis. In the retrorectal space, the urogenital-hypogastric sheath surrounded the fascia propria of the rectum posterolaterally as a layer of coat containing HGNs. The multiple layers of RF with different extensions are the anatomical basis of the formation of the urogenital-hypogastric sheath. As a special fascial structure in the retroperitoneal space and the pelvis, emphasis on its formation and morphology may be helpful for not only unifying the controversies about the relationship between the pelvic fascia and HGNs but also improving the intraoperative preservation of the HGNs by dissecting in the correct surgical plane.

A rare case of bilateral optic nerve sheath meningioma

Directory of Open Access Journals (Sweden)

Somen Misra

2014-01-01

Full Text Available A 60-year-old female presented with gradual, painless, progressive diminution of vision, and progressive proptosis of left eye since 7 years. Ophthalmological examination revealed mild proptosis and total optic atrophy in the left eye. Magnetic resonance imaging (MRI and computed tomography (CT brain with orbit showed bilateral optic nerve sheath meningioma (ONSM involving the intracranial, intracanalicular, intraorbital part of the optic nerve extending up to optic chiasma and left cavernous sinus.

Benign nerve sheath tumor of stomach

International Nuclear Information System (INIS)

Chaudry, N.U.; Zafar, S.; Haque, I.U.

2007-01-01

Gastrointestinal mesenchymal tumors are a group of tumors, which originate from the mesenchymal stem cells of the gastrointestinal tract. Gastric schwannoma is a very rare gastrointestinal mesenchymal tumor, which represents only 0.2% of all gastric tumors and 4% of all benign gastric neoplasms. We report a 55 years old lady who suffered from pain epigastrium, vomiting, occasionally with blood, loss of appetite and weight loss. Endoscopic examination showed a round submucosal tumor with a central ulceration along the greater curvature of the stomach. The pathological examination revealed a picture of spindle cell tumor. Immunohistochemical stain was strongly positive for S-100 protein stain, and non-reactive for CD34, CD117, consistent with benign nerve sheath tumor of stomach i.e. gastric schwannoma. (author)

An extra early mutant of pigeonpea

International Nuclear Information System (INIS)

Ravikesavan, R.; Kalaimagal, T.; Rathnaswamy, R.

2001-01-01

The redgram (Cajanus cajan (L.) Huth) variety 'Prabhat DT' was gamma irradiated with 100, 200, 300 and 400 Gy doses. Several mutants have been identified viz., extra early mutants, monostem mutants, obcordifoliate mutants and bi-stigmatic mutants. The extra early mutant was obtained when treated with 100 Gy dose. The mutant was selfed and forwarded from M 2 to M 4 generation. In the M 4 generation the mutant line was raised along with the parental variety. Normal cultural practices were followed and the biometrical observations were recorded. It was observed that for the characters viz., total number of branches per plant, number of pods per plants, seeds per pod, 100 seed weight and seed yield per plant there was no difference between the mutant and parent variety. Whereas, regarding the days to flowering and maturity the mutants were earlier than the parents. The observation was recorded from two hundred plants each. The mutant gives the same yield in 90 days as that of the parent variety in 107 days, which make it an economic mutant

Morphometric Analysis of Connective Tissue Sheaths of Sural Nerve in Diabetic and Nondiabetic Patients

Directory of Open Access Journals (Sweden)

Braca Kundalić

2014-01-01

Full Text Available One of the most common complications of diabetes mellitus is diabetic neuropathy. It may be provoked by metabolic and/or vascular factors, and depending on duration of disease, various layers of nerve may be affected. Our aim was to investigate influence of diabetes on the epineurial, perineurial, and endoneurial connective tissue sheaths. The study included 15 samples of sural nerve divided into three groups: diabetic group, peripheral vascular disease group, and control group. After morphological analysis, morphometric parameters were determined for each case using ImageJ software. Compared to the control group, the diabetic cases had significantly higher perineurial index (P<0.05 and endoneurial connective tissue percentage (P<0.01. The diabetic group showed significantly higher epineurial area (P<0.01, as well as percentage of endoneurial connective tissue (P<0.01, in relation to the peripheral vascular disease group. It is obvious that hyperglycemia and ischemia present in diabetes lead to substantial changes in connective tissue sheaths of nerve, particularly in peri- and endoneurium. Perineurial thickening and significant endoneurial fibrosis may impair the balance of endoneurial homeostasis and regenerative ability of the nerve fibers. Future investigations should focus on studying the components of extracellular matrix of connective tissue sheaths in diabetic nerves.

Dynamics of the Peripheral Membrane Protein P2 from Human Myelin Measured by Neutron Scattering--A Comparison between Wild-Type Protein and a Hinge Mutant.

Directory of Open Access Journals (Sweden)

Saara Laulumaa

Full Text Available Myelin protein P2 is a fatty acid-binding structural component of the myelin sheath in the peripheral nervous system, and its function is related to its membrane binding capacity. Here, the link between P2 protein dynamics and structure and function was studied using elastic incoherent neutron scattering (EINS. The P38G mutation, at the hinge between the β barrel and the α-helical lid, increased the lipid stacking capacity of human P2 in vitro, and the mutated protein was also functional in cultured cells. The P38G mutation did not change the overall structure of the protein. For a deeper insight into P2 structure-function relationships, information on protein dynamics in the 10 ps to 1 ns time scale was obtained using EINS. Values of mean square displacements mainly from protein H atoms were extracted for wild-type P2 and the P38G mutant and compared. Our results show that at physiological temperatures, the P38G mutant is more dynamic than the wild-type P2 protein, especially on a slow 1-ns time scale. Molecular dynamics simulations confirmed the enhanced dynamics of the mutant variant, especially within the portal region in the presence of bound fatty acid. The increased softness of the hinge mutant of human myelin P2 protein is likely related to an enhanced flexibility of the portal region of this fatty acid-binding protein, as well as to its interactions with the lipid bilayer surface requiring conformational adaptations.

Mutant heterosis in rice

International Nuclear Information System (INIS)

1987-01-01

In the variety TKM6 a high yielding semidwarf mutant has been induced. This TKM6 mutant was used in test crosses with a number of other varieties and mutants to examine the extent of heterosis of dwarfs in rice and to select superior crosses. An excerpt of the published data is given. It appears from the backcross of the mutant with its original variety, that an increase in number of productive tillers occurs in the hybrid, leading to a striking grain yield increase, while the semi-dwarf culm length (the main mutant character) reverts to the normal phenotype. In the cross with IR8 on the other hand, there is only a minimal increase in tiller number but a substantial increase in TGW leading to more than 30% yield increase over the better parent

Miscellaneous conditions of tendons, tendon sheaths, and ligaments.

Science.gov (United States)

Dyson, S J; Dik, K J

1995-08-01

The use of diagnostic ultrasonography has greatly enhances our ability to diagnose injuries of tendons and tendon sheaths that were previously either unrecognized or poorly understood. For may of these injuries, there is currently only a small amount of follow-up data. This article considers injuries of the deep digital flexor tendon and its accessory ligament, the carpal tunnel syndrome soft tissue swellings on the dorsal aspect of the carpus, intertubercular (bicipital) bursitis and bicipital tendinitis, injuries of the gastrocnemius tendon, common calcaneal tendinitis, rupture of peroneus (fibularis tertius) and ligaments injuries of the back.

Studies on mechanical, thermal and dynamic mechanical properties of untreated (raw) and treated coconut sheath fiber reinforced epoxy composites

International Nuclear Information System (INIS)

Suresh Kumar, S.M.; Duraibabu, D.; Subramanian, K.

2014-01-01

Highlights: • UTCSE and TCSE composites have been fabricated by compression molding technique. • The prepared specimens were characterized by FTIR, DMA, TGA and SEM techniques. • TCSE composite showed higher mechanical properties compared to UTCSE composite. • DMA showed that TCSE composite exhibited higher storage modulus than UTCSE composite. • TCSE composite showed higher thermal stability than UTCSE composite. - Abstract: The untreated (raw) coconut sheath fiber reinforced epoxy (UTCSE) composite and treated coconut sheath fiber reinforced epoxy (TCSE) composite have been fabricated using hand layup followed by compression molding technique. The prepared specimens were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic mechanical analysis (DMA), thermo gravimetric analysis (TGA) and scanning electron microscopy (SEM) techniques. The prepared specimens are cut as per ASTM Standards to measure tensile, flexural and impact strengths by using universal testing machine and izod impact tester respectively. The treated coconut sheath fiber reinforced epoxy composite (TCSE) posses higher mechanical strength and thermal stability compared to untreated (raw) coconut sheath fiber reinforced epoxy composite (UTCSE). In the SEM fracture analysis, TCSE composite showed better fiber–matrix bonding and absence of voids compared to UTCSE composite

A donor-specific QTL, exhibiting allelic variation for leaf sheath hairiness in a nested association mapping population, is located on barley chromosome 4H

KAUST Repository

Saade, Stephanie; Kutlu, Burcu; Draba, Vera; Fö rster, Karin; Schumann, Erika; Tester, Mark A.; Pillen, Klaus; Maurer, Andreas

2017-01-01

Leaf sheath hairiness is a morphological trait associated with various advantages, including tolerance to both abiotic and biotic stresses, thereby increasing yield. Understanding the genetic basis of this trait in barley can therefore improve the agronomic performance of this economically important crop. We scored leaf sheath hairiness in a two-year field trial in 1,420 BC1S3 lines from the wild barley nested association mapping (NAM) population HEB-25. Leaf sheath hairiness segregated in six out of 25 families with the reference parent Barke being glabrous. We detected the major hairy leaf sheath locus Hs (syn. Hsh) on chromosome 4H (111.3 cM) with high precision. The effects of the locus varied across the six different wild barley donors, with donor of HEB family 11 conferring the highest score of leaf sheath hairiness. Due to the high mapping resolution present in HEB-25, we were able to discuss physically linked pentatricopeptide repeat genes and subtilisin-like proteases as potential candidate genes underlying this locus. In this study, we proved that HEB-25 provides an appropriate tool to further understand the genetic control of leaf sheath hairiness in barley. Furthermore, our work represents a perfect starting position to clone the gene responsible for the 4H locus observed.

A donor-specific QTL, exhibiting allelic variation for leaf sheath hairiness in a nested association mapping population, is located on barley chromosome 4H

KAUST Repository

Saade, Stephanie

2017-12-07

Leaf sheath hairiness is a morphological trait associated with various advantages, including tolerance to both abiotic and biotic stresses, thereby increasing yield. Understanding the genetic basis of this trait in barley can therefore improve the agronomic performance of this economically important crop. We scored leaf sheath hairiness in a two-year field trial in 1,420 BC1S3 lines from the wild barley nested association mapping (NAM) population HEB-25. Leaf sheath hairiness segregated in six out of 25 families with the reference parent Barke being glabrous. We detected the major hairy leaf sheath locus Hs (syn. Hsh) on chromosome 4H (111.3 cM) with high precision. The effects of the locus varied across the six different wild barley donors, with donor of HEB family 11 conferring the highest score of leaf sheath hairiness. Due to the high mapping resolution present in HEB-25, we were able to discuss physically linked pentatricopeptide repeat genes and subtilisin-like proteases as potential candidate genes underlying this locus. In this study, we proved that HEB-25 provides an appropriate tool to further understand the genetic control of leaf sheath hairiness in barley. Furthermore, our work represents a perfect starting position to clone the gene responsible for the 4H locus observed.

The feasibility of transradial laser atherectomy for chronic total occlusion using the 5 Fr sheath system

Directory of Open Access Journals (Sweden)

Khaled Sherif

2016-05-01

Full Text Available Objective. We present a case of chronic total occlusion (CTO approached with LASER endovascular intervention by radial artery approach using a 5 French sheath. Case report. A 57-year-old man presented to our hospital having had retrosternal chest pain for two days. Physical examination was normal at the time of presentation. The laboratory tests were within normal limits, including cardiac enzymes except the lipid panel which showed hypertriglyceridemia. The patient underwent a myocardial perfusion scintigraphy stress test that revealed inferior wall ischemia, with normal left ventricular ejection fraction. A 5-French vascular sheath was placed in the right radial artery. Selective coronary artery angiography was performed, which showed right coronary artery (RCA CTO. A 5-French JR4 guide catheter successfully engaged the RCA and Laser angioplasty was performed across the CTO into the RCA. A marked improvement of flow was evident thereafter. Conclusion. To best of our knowledge this is the first case report showing the feasibility of laser atherectomy using the 5 French sheath system in a coronary arterial CTO.

The feasibility of transradial laser atherectomy for chronic total occlusion using the 5 Fr sheath system.

Science.gov (United States)

Sherif, Khaled; Yaqub, Yasir; Suarez, Jose A

2016-05-01

We present a case of chronic total occlusion (CTO) approached with LASER endovascular intervention by radial artery approach using a 5 French sheath. A 57-year-old man presented to our hospital having had retrosternal chest pain for two days. Physical examination was normal at the time of presentation. The laboratory tests were within normal limits, including cardiac enzymes except the lipid panel which showed hypertriglyceridemia. The patient underwent a myocardial perfusion scintigraphy stress test that revealed inferior wall ischemia, with normal left ventricular ejection fraction. A 5-French vascular sheath was placed in the right radial artery. Selective coronary artery angiography was performed, which showed right coronary artery (RCA) CTO. A 5-French JR4 guide catheter successfully engaged the RCA and Laser angioplasty was performed across the CTO into the RCA. A marked improvement of flow was evident thereafter. To best of our knowledge this is the first case report showing the feasibility of laser atherectomy using the 5 French sheath system in a coronary arterial CTO. Copyright © 2016 by Academy of Sciences and Arts of Bosnia and Herzegovina.

Effect of sheath material on critical current characteristics of MgB2 at high temperatures

International Nuclear Information System (INIS)

Kiuchi, M.; Yamauchi, K.; Kurokawa, T.; Otabe, E.S.; Matsushita, T.; Okada, M.; Tanaka, K.; Kumakura, H.; Kitaguchi, H.

2004-01-01

Critical current density and irreversibility field were measured at various temperatures and magnetic fields for MgB 2 PIT tape specimens with different sheaths materials. The experimental results were compared with theoretical estimations using the flux creep-flow model. It is found that the hardness of sheath material indirectly affects the pinning property only through the packing density of MgB 2 . It is considered that the critical current density is mainly determined by a low value of distributed local critical current density determined by grain connectivity. On the other hand, the irreversibility field which is approximately the same among the three tapes is mainly determined by the average pinning strength

Controlling laser ablation plasma with external electrodes. Application to sheath dynamics study and beam physics

International Nuclear Information System (INIS)

Isono, Fumika; Nakajima, Mitsuo; Hasegawa, Jun; Kawamura, Tohru; Horioka, Kazuhiko

2013-01-01

The potential of laser ablation plasma was controlled successfully by using external ring electrodes. We found that an electron sheath is formed at the plasma boundary, which plays an important role in the potential formation. When the positively biased plasma reaches a grounded grid, electrons in the plasma are turned away and ions are accelerated, which leads to the formation of a virtual anode between the grid and an ion probe. We think that this device which can raise the plasma potential up to order of kV can be applied to the study of sheath dynamics and to a new type of ion beam extraction. (author)

Comparative Oncogenomics for Peripheral Nerve Sheath Cancer Gene Discovery

Science.gov (United States)

2015-06-01

and MPNSTs by determining whether these same genes are mutated in human tumors. 15. SUBJECT TERMS Nothing listed 16. SECURITY CLASSIFICATION OF: 17...sheath tumour (MPNST). In: Louis DNO, H.;Wiestler,O.D.;Cavenee,W.K., editor. WHO Classification of Tumours of the Central Nervous System. Lyon: IARC...Location Sex Major or Micro WHO Grade H6 DRG Male Major IV H9 Trigeminal ganglion Female Major III H17 Trigeminal ganglion Male Major II H19 Sciatic

Jihadism, Narrow and Wide

DEFF Research Database (Denmark)

Sedgwick, Mark

2015-01-01

The term “jihadism” is popular, but difficult. It has narrow senses, which are generally valuable, and wide senses, which may be misleading. This article looks at the derivation and use of “jihadism” and of related terms, at definitions provided by a number of leading scholars, and at media usage....... It distinguishes two main groups of scholarly definitions, some careful and narrow, and some appearing to match loose media usage. However, it shows that even these scholarly definitions actually make important distinctions between jihadism and associated political and theological ideology. The article closes...

Influence of alkali metal oxides and alkaline earth metal oxides on the mitigation of stress corrosion cracking in CANDU fuel sheathing

Energy Technology Data Exchange (ETDEWEB)

Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2015-07-01

Stress corrosion cracking (SCC)can cause failures of CANDU Zircaloy-4 fuel sheathing. The process occurs when a corrosive element (i.e.,iodine) interacts with a susceptible material that is under sufficient strain at a high temperature. Currently, there is an ongoing effort to improve SCC mitigation strategies for future iterations of CANDU reactors. A potential mechanism for SCC mitigation involves utilizing alkali metal oxides and alkaline earth metal oxides that will sequester corrosive iodine while actively repairing a protective oxide layer on the sheath. SCC tests performed with sodium oxide (Na{sub 2}O) and calcium oxide (CaO) have shown to decrease significantly the sheath degradation. (author)

Shear flow instability in a partially-ionized plasma sheath around a fast-moving vehicle

International Nuclear Information System (INIS)

Sotnikov, V. I.; Mudaliar, S.; Genoni, T. C.; Rose, D. V.; Oliver, B. V.; Mehlhorn, T. A.

2011-01-01

The stability of ion acoustic waves in a sheared-flow, partially-ionized compressible plasma sheath around a fast-moving vehicle in the upper atmosphere, is described and evaluated for different flow profiles. In a compressible plasma with shear flow, instability occurs for any velocity profile, not just for profiles with an inflection point. A second-order differential equation for the electrostatic potential of excited ion acoustic waves in the presence of electron and ion collisions with neutrals is derived and solved numerically using a shooting method with boundary conditions appropriate for a finite thickness sheath in contact with the vehicle. We consider three different velocity flow profiles and find that in all cases that neutral collisions can completely suppress the instability.

Blazar Sheath Illumination of the Outer Molecular Torus: A Resolution of the Seed Photon Problem for the Far-GeV Blazar Flares

Science.gov (United States)

Breiding, Peter; Georganopoulos, Markos; Meyer, Eileen T.

2018-01-01

Recent multiwavelength work led by the Boston University blazar group (e.g., Marscher et al.) strongly suggests that a fraction of the blazar flares seen by the Fermi Large Area Telescope (LAT) take place a few to several pc away from the central engine. However, at such distances from the central engine, there is no adequate external photon field to provide the seed photons required for producing the observed GeV emission under leptonic inverse Compton (IC) models. A possible solution is a spine-sheath geometry for the emitting region (MacDonald et al., but see Nalewajko et al.). Here we use the current view of the molecular torus (e.g., Elitzur; Netzer), in which the torus extends a few pc beyond the dust sublimation radius with dust clouds distributed with a declining density for decreasing polar angle. We show that for a spine-sheath blazar jet embedded in the torus, the wide beaming pattern of the synchrotron radiation of the relatively slow sheath will heat molecular clouds with subsequent IR radiation that will be highly boosted in the spine comoving frame, and that under reasonable conditions this photon field can dominate over the sheath photons directly entering the spine. If the sheath is sufficiently luminous it will sublimate the dust, and if the sheath synchrotron radiation extends to optical-UV energies (as may happen during flares), this will illuminate the sublimated dust clouds to produce emission lines that will vary in unison with the optical-UV continuum, as has been very recently reported for blazar CTA 102 (Jorstad et al.).

Device Physics of Narrow Gap Semiconductors

CERN Document Server

Chu, Junhao

2010-01-01

Narrow gap semiconductors obey the general rules of semiconductor science, but often exhibit extreme features of these rules because of the same properties that produce their narrow gaps. Consequently these materials provide sensitive tests of theory, and the opportunity for the design of innovative devices. Narrow gap semiconductors are the most important materials for the preparation of advanced modern infrared systems. Device Physics of Narrow Gap Semiconductors offers descriptions of the materials science and device physics of these unique materials. Topics covered include impurities and defects, recombination mechanisms, surface and interface properties, and the properties of low dimensional systems for infrared applications. This book will help readers to understand not only the semiconductor physics and materials science, but also how they relate to advanced opto-electronic devices. The last chapter applies the understanding of device physics to photoconductive detectors, photovoltaic infrared detector...

Eye and sheath folds in turbidite convolute lamination: Aberystwyth Grits Group, Wales

Science.gov (United States)

McClelland, H. L. O.; Woodcock, N. H.; Gladstone, C.

2011-07-01

Eye and sheath folds are described from the turbidites of the Aberystwyth Group, in the Silurian of west Wales. They have been studied at outcrop and on high resolution optical scans of cut surfaces. The folds are not tectonic in origin. They occur as part of the convolute-laminated interval of each sand-mud turbidite bed. The thickness of this interval is most commonly between 20 and 100 mm. Lamination patterns confirm previous interpretations that convolute lamination nucleated on ripples and grew during continued sedimentation of the bed. The folds amplified vertically and were sheared horizontally by continuing turbidity flow, but only to average values of about γ = 1. The strongly curvilinear fold hinges are due not to high shear strains, but to nucleation on sinuous or linguoid ripples. The Aberystwyth Group structures provide a warning that not all eye folds in sedimentary or metasedimentary rocks should be interpreted as sections through high shear strain sheath folds.

Winter barley mutants created in the Ukraine

International Nuclear Information System (INIS)

Zayats, O.M.

2001-01-01

Full text: Increasing fodder and protein production is one of the objectives of the development of agriculture in Ukraine. Higher productivity of fodder crops, due to new highly productive varieties, is the means to meet this aim. Winter barley is an important crop for fodder purposes. The climate of the Ukraine is favourable for growing this crop. The areas used for the growth of winter barley are however, small (500,000-550,000 ha) and there is a shortage of good quality varieties. The main aim of the work was therefore to create new varieties of highly productive winter barley, of good quality. The new varieties and mutation lines of winter barley were created under the influence of water solutions of N-nitroso-N-methylurea (NMH - 0,012, 0,005%), N-nitroso-N-ethylurea (NEH - 0,05; 0.025; 0,012%) ethyleneimine (EI - 0,02; 0,01; 0,005%) on winter barley seeds of the varieties of local and foreign selections. On the basis of many years of investigations (1984-94) the following mutations were described: hard-grained, winter-hardiness, earliness, middle-maturity, late-maturity, wide and large leaves, narrow leaves, multinodal, great number of leaves, great number of flowers, strong stem (lodging resistant), tallness, semi-dwarfness, dwarfness, and high productivity. Particularly valuable are mutants with high productivity of green bulk. Their potential yield is 70 t/ha. As a result of the work two varieties of winter barley 'Shyrokolysty' and 'Kormovy' were released into the State register of plant varieties of the Ukraine. The other valuable mutant genotypes are used in cross breeding programmes. (author)

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

Energy Technology Data Exchange (ETDEWEB)

Grin, A.; Lstiburek, J.

2014-09-01

This guide provides information and recommendations to the following groups: insulation contractors; general contractors; builders; home remodelers; mechanical contractors; and homeowners, as a guide to the work that needs to be done. The order of work completed during home construction and retrofit improvements is important. Health and safety issues must be addressed first and are more important than durability issues. And durability issues are more important than saving energy. Not all techniques can apply to all houses. Special conditions will require special action. Some builders or homeowners will wish to do more than the important but basic retrofit strategies outlined by this guide. The following are best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant items were discussed with the group which are required to make taped insulating sheathing a simple, long term, and durable drainage plane: 1. Horizontal joints should be limited or eliminated wherever possible; 2. Where a horizontal joint exists use superior materials; 3. Frequent installation inspection and regular trade training are required to maintain proper installation. Section 5 of this measure guideline contains the detailed construction procedure for the three recommended methods to effectively seal the joints in exterior insulating sheathing to create a simple, long term, and durable drainage plane.

Cutoff effects of electron velocity distribution to the properties of plasma parameters near the plasma-sheath boundary

International Nuclear Information System (INIS)

Jelic, N.

2011-01-01

The plasma properties under high thermodynamic non-equilibrium condition, established due to the presence of electrically biased electrode, are investigated. Assumption of electron cut-off velocity distribution function (VDF), as done by Andrews and Varey in their investigations of the sheath region [J. Phys. A 3, 413 (1970)], has been extended here to both plasma and sheath regions. Analytic expressions for the moments of electron VDF, as well as for the electron screening temperature function dependence on the plasma-sheath local potential are derived. In deriving the ion velocity distribution the ''standard'' assumption of strict plasma quasineutrality, or equivalently vanishing of the plasma Debye length, is employed, whereas the ions are assumed to be generated at rest over the plasma region. However, unlike the standard approach of solving the plasma equation, where pure Boltzmann electron density profile is used, here we employ modified Boltzmann's electron density profile, due to cutoff effect of the electron velocity distribution. It is shown that under these conditions the quasineutrality equation solution is characterised by the electric field singularity for any negative value of the electrode bias potential as measured with respect to the plasma potential. The point of singularity i.e., the plasma length and its dependence on the electrode bias and sheath potential is established for the particular case of ionization profile mechanism proportional to the local electron density. Relevant parameters for the kinetic Bohm criterion are explicitly calculated for both ions and electrons, for arbitrary electrode bias.

Site-directed mutagenesis of HIV-1 vpu gene demonstrates two clusters of replication-defective mutants with distinct ability to down-modulate cell surface CD4 and tetherin

Directory of Open Access Journals (Sweden)

Masako Nomaguchi

2010-11-01

Full Text Available HIV-1 Vpu acts positively on viral infectivity by mediating CD4 degradation in endoplasmic reticulum and enhances virion release by counteracting a virion release restriction factor, tetherin. In order to define the impact of Vpu activity on HIV-1 replication, we have generated a series of site-specific proviral vpu mutants. Of fifteen mutants examined, seven exhibited a replication-defect similar to that of a vpu-deletion mutant in a lymphocyte cell line H9. These mutations clustered in narrow regions within transmembrane domain (TMD and cytoplasmic domain (CTD. Replication-defective mutants displayed the reduced ability to enhance virion release from a monolayer cell line HEp2 without exception. Upon transfection with Vpu expression vectors, neither TMD mutants nor CTD mutants blocked CD4 expression at the cell surface in another monolayer cell line MAGI. While TMD mutants were unable to down-modulate cell surface tetherin in HEp2 cells, CTD mutants did quite efficiently. Confocal microscopy analysis revealed the difference of intracellular localization between TMD and CTD mutants. In total, replication capability of HIV-1 carrying vpu mutations correlates well with the ability of Vpu to enhance virion release and to impede the cell surface expression of CD4 but not with the ability to down-modulate cell surface tetherin. Our results here suggest that efficient viral replication requires not only down-regulation of cell surface tetherin but also its degradation.

Modelling of DC electric fields induced by RF sheath in front of ICRF antenna

International Nuclear Information System (INIS)

Faudot, E.; Heuraux, S.; Colas, L.

2003-01-01

Reducing the ICRF (ion cyclotron range frequency) antenna-plasma interaction is one of the key points for reaching very long tokamak discharges. One problem which limits such discharges, is the appearance of hot spots on the surface of the antenna: Radio Frequency (RF) sheaths modify the properties of the edge plasma by rectifying the RF potential along open magnetic field lines and can induce hot spots. This paper investigates the corrections to sheath potentials introduced by the interactions between adjacent flux tubes. Our theoretical study started from an oscillating double Langmuir probe model, in which a transverse influx of current was included. This model was confronted with 1D PIC simulations along a magnetic field line, and demonstrated that current exchanges can decrease mean potentials. A 2D electrostatic fluid code was then developed, which couples adjacent flux tubes in a poloidal cross section with collisional conductivity or polarization currents. It showed that transverse currents are able to smooth structures smaller than a characteristic size in the sheath potential maps (results for Tore Supra). These computed rectified potentials can be used to obtain the DC electric fields in front of the antenna. And then, it gives an estimate of the particle drift and the energy flux on the antenna structure, which can explain hot spots. (author)

The MRI appearance of the optic nerve sheath following fenestration for benign intracranial hypertension

Energy Technology Data Exchange (ETDEWEB)

Sallomi, D.; Taylor, H.; Hibbert, J.; Sanders, M.D.; Spalton, D.J.; Tonge, K. [Guys and St. Thomas` Hospitals, London (United Kingdom)

1998-09-01

Optic nerve fenestration is carried out in cases of severe benign intracranial hypertension. This study aimed to monitor the optic nerve sheath appearances and orbital changes that occur following this procedure. The eight patients were all female with an average age of 37.3 years and a range of 20-58 years. The duration of symptoms was 2-6 years. Symptoms included headaches, diplopia and visual obscurations. Examination revealed severe papilledema. All investigations, including MRI, biochemical and immunological tests, were negative. Patients had fenestration of a 2 mm x 3 mm segment of the medial aspect of the optic nerve sheath. Imaging was obtained with a 1 T MRI machine using a head coil. Coronal, axial and sagittal 3 mm contiguous sections using STIR sequences with TR 4900 ms, IT 150 ms and TE 60 ms were obtained. Five patients showed clinical improvement. The post-operative MRI findings in four of these included a decreased volume of cerebrospinal fluid (CSF) around the optic nerve sheaths and a localized collection of fluid within the orbit. There were no MRI changes in the three patients with no clinical improvement. Decreased CSF volume around the optic nerve and a fluid collection within the orbit may indicate a favorable outcome in optic nerve fenestration. (orig.) With 3 figs., 12 refs.

Transjugular Intrahepatic Portosystemic Shunt Flow Reduction with Adjustable Polytetrafluoroethylene-Covered Balloon-Expandable Stents Using the “Sheath Control” Technique

Energy Technology Data Exchange (ETDEWEB)

Blue, Robert C., E-mail: Robert.c.blue@gmail.com; Lo, Grace C.; Kim, Edward; Patel, Rahul S.; Scott Nowakowski, F.; Lookstein, Robert A.; Fischman, Aaron M. [Icahn School of Medicine at Mount Sinai, Interventional Radiology Section, Department of Radiology (United States)

2016-06-15

PurposeA complication of transjugular intrahepatic portosystemic shunts (TIPS) placement is refractory portosystemic encephalopathy (PSE) often requiring TIPS reduction. We report the results of a “sheath control technique” utilizing constraining sheaths during deployment of polytetrafluoroethylene (PTFE)-covered balloon-expandable stents, minimizing stent migration, and providing additional procedural control.MethodsTIPS reduction was performed in 10 consecutive patients for PSE using Atrium iCast covered stents (Atrium Maquet Getinge Group, Germany). Within the indwelling TIPS stent, a 9 mm × 59 mm iCast stent was deployed with 2 cm exposed from the sheath’s distal end and the majority of the stent within the sheath to create the distal hourglass shape. During balloon retraction, the stent was buttressed by the sheath. The proximal portion of the stent was angioplastied to complete the hourglass configuration, and the central portion of the stent was dilated to 5 mm. Demographics, pre- and post-procedure laboratory values, and outcomes were recorded.ResultsTen patients underwent TIPS reduction with 100 % technical success. There was no stent migration during stent deployment. All patients experienced initial improvement of encephalopathy. One patient ultimately required complete TIPS occlusion for refractory PSE, and another developed TIPS occlusion 36 days post-procedure. There was no significant trend toward change in patients’ MELD scores immediately post-procedure or at 30 days (p = 0.46, p = 0.47, respectively).ConclusionTIPS reduction using Atrium iCast PTFE balloon-expandable stents using the “sheath control technique” is safe and effective, and minimizes the risk of stent migration.

Frontal plane fractures of the accessory carpal bone and implications for the carpal sheath of the digital flexor tendons.

Science.gov (United States)

Minshall, G J; Wright, I M

2014-09-01

Accurate radiological and ultrasonographic descriptions of frontal plane fractures of the accessory carpal bone (ACB) are lacking, and implications of these fractures for the carpal sheath and its contents have not previously been reported. Aims were as follows: 1) to describe the location and radiological features of frontal plane fractures of the ACB; 2) to document communication of displaced fractures with the carpal sheath and consequent injury to the deep digital flexor tendon (DDFT); 3) to describe ultrasonographic identification of lesions; and 4) to report tenoscopic evaluation and treatment. Retrospective case series. Analysis of frontal plane fractures of the ACB referred to a single hospital between 2006 and 2012, including review of radiographic, ultrasonographic and tenoscopic images. Nine fractures were identified, of which 8 displaced fractures all communicated with the carpal sheath. Comminuted fragments and/or protruding fracture margins lacerated the lateral margin of the enclosed DDFT. This was identifiable ultrasonographically and confirmed at tenoscopy in 7 cases. Treatment in these horses consisted of removal of torn tendon tissue together with fragmentation and protuberant fracture edges, and 7 of 7 cases returned to work. One horse with a nondisplaced fracture was managed with immobilisation; the fracture healed, and the horse returned to work. One horse with a displaced fracture was retired to stud. Frontal plane fractures of the ACB occur palmar to the groove in its lateral margin for the tendon of insertion of ulnaris lateralis. Comminuted fragments can displace distally within the carpal sheath to a mid-metacarpal level or abaxially to lie extrathecally, lateral to the parent bone. Displaced fractures communicate with the carpal sheath and traumatise the DDFT. © 2013 EVJ Ltd.

Comment on open-quote open-quote Bohm criterion for the collisional sheath close-quote close-quote [Phys. Plasmas 3, 1459 (1996)

International Nuclear Information System (INIS)

Riemann, K.U.; Meyer, P.

1996-01-01

Recently, Valentini [Phys. Plasmas 3, 1459 (1996)] investigated the influence of collisions on the space charge formation and derived a modified Bohm criterion accounting for collisions in the sheath. It is shown that this derivation is wrong and is based on a misinterpretation of the plasma sheath concept. copyright 1996 American Institute of Physics

Influence of alkali metal oxides and alkaline earth metal oxides on the mitigation of stress corrosion cracking in CANDU fuel sheathing

Energy Technology Data Exchange (ETDEWEB)

Metzler, J.; Ferrier, G.A.; Farahani, M.; Chan, P.K.; Corcoran, E.C., E-mail: Joseph.Metzler@rmc.ca [Royal Military College of Canada, Kingston, ON (Canada)

2015-07-01

This work investigates strategies to mitigate stress corrosion cracking (SCC) in Zircaloy-4 sheathing materials. The CANLUB coatings currently used in CANDU reactors contain both alkali metal and alkaline earth metal impurities, which can exist as oxides (e.g., Na{sub 2}O and CaO). It is believed that when the corrosive fission product iodine reacts with these oxides, the iodine can be sequestered through the formation of an iodide (e.g.,NaI and CaI{sub 2}). The subsequent O{sub 2} release may repair cracks in the protective ZrO{sub 2} layer on the sheathing, shielding the Zircaloy-4 sheathing from further corrosive fission product attack. For this investigation, O{sub 2} gas, Na{sub 2}O, and CaO were separately introduced into an environment wherein slotted Zircaloy-4 rings endure mechanical stresses in iodine vapour at high temperatures. Controlled additions of O{sub 2} gas created a slight reduction in the corrosive attack on Zircaloy-4 sheathing, while the inclusion of Na{sub 2}O and CaO lead to greater reductions. (author)

Narrow dibaryon resonances

International Nuclear Information System (INIS)

Kajdalov, A.B.

1986-01-01

Experimental data on np interactions indicating to existence of narrow resonances in pp-system are discussed. Possible theoretical interpretations of these resonances are given. Experimental characteristics of the dibaryon resonances with isospin I=2 are considered

Selection and agronomic evaluation of induced mutant lines of sesame

International Nuclear Information System (INIS)

Hoballah, A.A.

2001-01-01

%), capsules/plant (33.6%), capsule length (19.0%), 100-seed weight (18.6%) and plant height (12.1%). Analysis of variance for combining ability indicated that general (GCA) and specific (SCA) combining ability variances were highly significant for all studied traits. Estimates of GCA effects showed that EXM90, EFM92 and Mutant 8 were the best general combiners for earliness; the variety Giza 32 and Mutant 48 the best for seed yield and number of capsules per plant. Both parents and their derived crosses could be utilized for hybrid sesame production and varietal improvement in terms of the probability of selecting desirable segregants for yield and yield components. Estimates of the type of gene action confirmed the importance of both additive and non-additive (dominant) gene effects in the inheritance of the studied characters in both F 1 and F 2 generations. However the dominance components were larger than the additive ones for most investigated traits in the F 1 and vice versa in the F 2 . Overdominance was also noted. Heritability in narrow sense (H n ) was low for most characters in the F 1 . On the other hand, high values of heritability (H n ) were recorded for all the investigated traits in the F 2 , indicating that the genetic variance associated with those traits was mostly due to additive effects of genes, and therefore, it could be concluded that selection based on the accumulation of additive effects would be very successful in improving such traits. (author)

Long-term stability of intracortical recordings using perforated and arrayed Parylene sheath electrodes

Science.gov (United States)

Hara, Seth A.; Kim, Brian J.; Kuo, Jonathan T. W.; Lee, Curtis D.; Meng, Ellis; Pikov, Victor

2016-12-01

Objective. Acquisition of reliable and robust neural recordings with intracortical neural probes is a persistent challenge in the field of neuroprosthetics. We developed a multielectrode array technology to address chronic intracortical recording reliability and present in vivo recording results. Approach. The 2 × 2 Parylene sheath electrode array (PSEA) was microfabricated and constructed from only Parylene C and platinum. The probe includes a novel three-dimensional sheath structure, perforations, and bioactive coatings that improve tissue integration and manage immune response. Coatings were applied using a sequential dip-coating method that provided coverage over the entire probe surface and interior of the sheath structure. A sharp probe tip taper facilitated insertion with minimal trauma. Fabricated probes were subject to examination by optical and electron microscopy and electrochemical testing prior to implantation. Main results. 1 × 2 arrays were successfully fabricated on wafer and then packaged together to produce 2 × 2 arrays. Then, probes having electrode sites with adequate electrochemical properties were selected. A subset of arrays was treated with bioactive coatings to encourage neuronal growth and suppress inflammation and another subset of arrays was implanted in conjunction with a virally mediated expression of Caveolin-1. Arrays were attached to a custom-made insertion shuttle to facilitate precise insertion into the rat motor cortex. Stable electrophysiological recordings were obtained during the period of implantation up to 12 months. Immunohistochemical evaluation of cortical tissue around individual probes indicated a strong correlation between the electrophysiological performance of the probes and histologically observable proximity of neurons and dendritic sprouting. Significance. The PSEA demonstrates the scalability of sheath electrode technology and provides higher electrode count and density to access a greater volume for recording

Gamma-radiation Mutagenesis in Genetically Unstable Barley Mutants. Pt. 2. Comparison of Various Mutants

International Nuclear Information System (INIS)

Balchiuniene, L.

1995-01-01

Spontaneous and gamma-induced mutability was compared in two groups of genetically unstable barley ear structure mutants - tweaky spike (tw) and branched ear (be). Instability in different loci causes different levels of spontaneous and gamma-induced mutability. A high spontaneous level of chlorophyll mutations is peculiar to be-ust mutants. It is suggested that the high level of induced chlorophyll mutations in allelic tw mutants is a result of better surviving of chlorophyll mutation carriers in the genotypical-physiological environment created by mutant tw alleles. (author). 6 refs., 2 tabs

Access site-related complications after transradial catheterization can be reduced with smaller sheath size and statins.

Science.gov (United States)

Honda, Tsuyoshi; Fujimoto, Kazuteru; Miyao, Yuji; Koga, Hidenobu; Hirata, Yoshihiro

2012-09-01

The aim of this study was to investigate the risk factors for access site-related complications after transradial coronary angiography (CAG) or percutaneous coronary intervention (PCI). Transradial PCI has been shown to reduce access site-related bleeding complications compared with procedures performed through a femoral approach. Although previous studies focused on risk factors for access site-related complications after a transfemoral approach or transfemoral and transradial approaches, it is uncertain which factors affect vascular complications after transradial catheterization. We enrolled 500 consecutive patients who underwent transradial CAG or PCI. We determined the incidence and risk factors for access site-related complications such as radial artery occlusion and bleeding complications. Age, sheath size, the dose of heparin and the frequency of PCI (vs. CAG) were significantly greater in patients with than without bleeding complications. However, body mass index (BMI) was significantly lower in patients with than without bleeding complications. Sheath size was significantly higher and the frequency of statin use was significantly lower in patients with than without radial artery occlusion. Multiple logistic analysis revealed that sheath size [odds ratio (OR) 5.5; P strategy that could prevent radial artery occlusion after transradial procedures.

Promising rice mutants

International Nuclear Information System (INIS)

Hakim, L.; Azam, M.A.; Miah, A.J.; Mansur, M.A.; Akanda, H.R.

1988-01-01

Two induced mutants namely, Mut NS 1 (tall) and Mut NS 5 (semi-dwarf) derived from rice variety Nizersail were evaluated for various agronomic characters at four locations in Bangladesh. Both the mutants matured about three weeks earlier and yielded significantly higher than the parent variety Nizersail. (author). 3 tabs., 9 refs

Application of Green's differential equation to the analysis of ion-matrix sheaths around wedge-shaped cathodes

International Nuclear Information System (INIS)

Donolato, C

2005-01-01

A relation between the gradient of the electric field and mean curvature of equipotential surfaces (Green's differential equation) is applied to a two-dimensional free-boundary problem arising in the study of ion sheaths around wedge-shaped cathodes. With the assumption that the equipotential lines are hyperbolae, this relation leads to a nonlinear ordinary differential equation for the potential along the bisector line of the wedge. An approximate solution is found, which yields, in particular, the sheath width along this line as a function of the wedge angle. The resulting values are in good agreement with published results obtained by numerically solving Poisson's equation

Transport current dependence of the hysteresis loss in silver sheathed BSCOO-2212 conductors

NARCIS (Netherlands)

Hemmes, Herman K.; Woudstra, Martin J.; ten Kate, Herman H.J.; Tenbrink, Johannes

1994-01-01

A technique is described to study the critical current density and penetration fieldassociated with the transport current in a silver sheathed BSCCO conductor. A transport current flowing in a conductor in a varying magnetic field will only influence magnetisation currents that are in competition

Verification of a mechanistic model for the strain rate of zircaloy-4 fuel sheaths during transient heating

International Nuclear Information System (INIS)

Hunt, C.E.L.

1980-10-01

A mechanistic strain rate model for Zircaloy-4, named NIRVANA, was tested against experiments where pressurized fuel sheaths were strained during complex temperature-stress-time histories. The same histories were then examined to determine the spread in calculated strain which may be expected because of variations in dimensions, chemical content and mechanical properties which are allowed in the fuel sheath specifications. It was found that the variations allowed by the specifications could result in a probable spread in the predicted strain of plus or minus a factor of two from the mean value. The experimental results were well within this range. (auth)

Reexcision Perineural Invasion and Epithelial Sheath Neuroma Possibly on a Spectrum of Postinjury Reactive Hyperplasia Mediated by IL-6.

Science.gov (United States)

Wang, James Y; Nuovo, Gerard; Kline, Mitchell; Magro, Cynthia M

2017-01-01

Epithelial sheath neuroma is a rarely recognized but established entity in the medical literature. First described in 2000 by Requena et al, there have only been 7 published cases to date, mostly in female patients and presenting as symptomatic solitary lesions on the back without a known history of trauma. In 2006, Beer et al described and reviewed a dozen cases in which epithelial sheath neuroma-like features were seen in the advent of a surgical procedure, which was termed "re-excision perineural invasion" and attributed to possible eccrine duct implantation during surgery. Our case is a 66-year-old male patient who underwent an excision of a melanocytic neoplasm in which a reactive epithelial sheath neuroma was incidentally discovered in the excision specimen, adjacent to the biopsy site cicatrix. Histologically, there was benign cutaneous nerve hyperplasia with a proliferation of squamous epithelium in intimate apposition to the nerve bundles in the superficial dermis. We postulate that the process active in the formation of re-excision perineural invasion is the same as in epithelial sheath neuroma and that minor trauma not appreciable on histologic examination is responsible in the latter entity. We performed IL-6 staining and documented that IL-6 was upregulated at the interface of the nerve and reactive epithelium, but was absent in nerves distant from the site of surgery, suggesting that IL-6 may be essential to the lesion's development. The recognition of reactive epithelial sheath neuroma including the subcategory of re-excision perineural invasion is crucial for the dermatopathologist to prevent mislabeling this reactive entity as a perineural squamous cell carcinoma, which has clinical consequences for the patient such as wider re-excision and radiation treatment. Additionally, we have identified a potential pathophysiologic basis for this lesion.

The cld mutation: narrowing the critical chromosomal region and selecting candidate genes.

Science.gov (United States)

Péterfy, Miklós; Mao, Hui Z; Doolittle, Mark H

2006-10-01

Combined lipase deficiency (cld) is a recessive, lethal mutation specific to the tw73 haplotype on mouse Chromosome 17. While the cld mutation results in lipase proteins that are inactive, aggregated, and retained in the endoplasmic reticulum (ER), it maps separately from the lipase structural genes. We have narrowed the gene critical region by about 50% using the tw18 haplotype for deletion mapping and a recombinant chromosome used originally to map cld with respect to the phenotypic marker tf. The region now extends from 22 to 25.6 Mbp on the wild-type chromosome, currently containing 149 genes and 50 expressed sequence tags (ESTs). To identify the affected gene, we have selected candidates based on their known role in associated biological processes, cellular components, and molecular functions that best fit with the predicted function of the cld gene. A secondary approach was based on differences in mRNA levels between mutant (cld/cld) and unaffected (+/cld) cells. Using both approaches, we have identified seven functional candidates with an ER localization and/or an involvement in protein maturation and folding that could explain the lipase deficiency, and six expression candidates that exhibit large differences in mRNA levels between mutant and unaffected cells. Significantly, two genes were found to be candidates with regard to both function and expression, thus emerging as the strongest candidates for cld. We discuss the implications of our mapping results and our selection of candidates with respect to other genes, deletions, and mutations occurring in the cld critical region.

[The transrectus sheath preperitoneal procedure: a safe, effective and cheap surgical approach to inguinal hernia?].

Science.gov (United States)

Prins, M W Wiesje; Voropai, D A Dasha; van Laarhoven, C J H M Kees; Akkersdijk, Willem L

2013-01-01

The main complication of surgery for inguinal hernia is chronic postoperative pain. This is often reported following the Lichtenstein procedure. A new, open surgical technique for the repair of inguinal hernia has been developed. This procedure is called the transrectus sheath preperitoneal procedure (TREPP). At TREPP a lightweight mesh with a ring made of memory metal is introduced into the preperitoneal space through the transrectus sheath. The first results of this operative technique are very promising: short operation time, short learning curve and not many patients with chronic postoperative pain. In a randomised, multi-centre study which will start mid-2013 (ISRCTN18591339), the TREPP procedure is compared with the transinguinal preperitoneal procedure. The primary outcome measure of this study is chronic postoperative pain.

Gamma ray induced mutants in Coleus

Energy Technology Data Exchange (ETDEWEB)

Vasudevan, K; Jos, J S [Central Tuber Crops Research Institute, Trivandrum, Kerala (India)

1988-07-01

The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M{sub 1}V{sub 1} generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m{sup 2} area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing.

Gamma ray induced mutants in Coleus

International Nuclear Information System (INIS)

Vasudevan, K.; Jos, J.S.

1988-01-01

The germplasm collection of Chinese potato (Coleus parviflorus Benth) contains almost no variation for yield contributing traits. The crop does not produce seeds. Treatment of underground tubers with 1 kR, 2 kR, 3 kR and 4 kR gamma rays resulted in 50 morphologically different mutants which are maintained as mutant clones. In the M 1 V 1 generation, suspected mutant sprouts, were carefully removed and grown separately. The most interesting mutant types are the following: (i) erect mutant with spoon shaped light green leaves, 30 cm long inflorescences against 20 cm in the control, cylindrical tubers measuring ca. 7.0 cm long and 3 cm girth against 4 cm and 2.5 cm in the control (ii) early mutants 1 and 2, one having less leaf serration, the other having light green small leaves and dwarf type (iii) fleshy leaf mutant, dark green, thick and smooth leaves. Control plants spread almost in 1 m 2 area and bear tubers from the nodes of branches. In the early mutants tuber formation is mainly restricted to the base of the plant, which makes harvest easier. The crop usually matures within 150 - 160 days, the early mutants are ready for harvest 100 days after planting. As the mutants are less spreading, the yield could be increased by closer spacing

Giant cell tumour of tendon sheath and synovial membrane: A review of 26 cases.

Science.gov (United States)

Kant, Kumar Shashi; Manav, Ajoy Kumar; Kumar, Rakesh; Abhinav; Sinha, Vishvendra Kumar; Sharma, Akshat

2017-11-01

Aim of our study is to highlight the incidence and benign nature of Giant cell tumour of tendon sheath and need for complete removal, thus minimizing the chances of recurrence. A total of 26 cases of Giant cell tumour of tendon sheath operated in the department of Orthopaedics, Patna Medical College & Hospital, Patna from 2003 to 2010 were included in this study. The surgery was performed after clinical evaluation of the lesion and Fine Needle Aspiration Cytology (FNAC). The tumour underwent en bloc marginal excision. The patients were followed up for minimum two year. Our study population consisted of 18 females and 8 males. The mean age at the time of surgery was 38.3 years (range, 18-62 years). Twenty three cases were found in the 3rd and 4th decade. Twenty two cases involved upper extremity and only 4 cases in lower extremity. MRI was done in 2 cases where diagnosis was in doubt. Bony indentation on X-ray film was found in 7 cases and thorough curettage of cortical shell was done. All the cases were treated by marginal excision. Three cases developed post-operative stiffness but regained full range of movement with physiotherapy. Sensory impairment was seen in 3 cases. Recurrence occurred in 2 case and they were treated by repeat marginal excision. Meticulous en-masse marginal excision of the giant cell tumour of tendon sheath in blood less field using magnification is the treatment of choice.

Laser-induced fluorescence measurements of argon and xenon ion velocities near the sheath boundary in 3 ion species plasmas

Energy Technology Data Exchange (ETDEWEB)

Yip, Chi-Shung; Hershkowitz, Noah [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Severn, Greg [Department of Physics, University of San Diego, San Diego, California 92110 (United States); Baalrud, Scott D. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

2016-05-15

The Bohm sheath criterion is studied with laser-induced fluorescence in three ion species plasmas using two tunable diode lasers. Krypton is added to a low pressure unmagnetized DC hot filament discharge in a mixture of argon and xenon gas confined by surface multi-dipole magnetic fields. The argon and xenon ion velocity distribution functions are measured at the sheath-presheath boundary near a negatively biased boundary plate. The potential structures of the plasma sheath and presheath are measured by an emissive probe. Results are compared with previous experiments with Ar–Xe plasmas, where the two ion species were observed to reach the sheath edge at nearly the same speed. This speed was the ion sound speed of the system, which is consistent with the generalized Bohm criterion. In such two ion species plasmas, instability enhanced collisional friction was demonstrated [Hershkowitz et al., Phys. Plasmas 18(5), 057102 (2011).] to exist which accounted for the observed results. When three ion species are present, it is demonstrated under most circumstances the ions do not fall out of the plasma at their individual Bohm velocities. It is also shown that under most circumstances the ions do not fall out of the plasma at the system sound speed. These observations are also consistent with the presence of the instabilities.

Repairing a steam generator tube by inserting a sheath

International Nuclear Information System (INIS)

Gaudin, J.P.

1986-01-01

According to the invention, the mechanical deformation of the sheath, realized by expansion in its end part opposite to the expanded end within the tube plate, is situated along a limited height, and the parameters of the said mechanical deformation are calculated according to the welding parameters applied consecutively. Besides, the said welding parameters are determined according to the initial mechanical deformation to obtain stress relaxation more particularly in the singular zones of the mechanical deformation. The present invention applies to the repair of PWR steam generator tubes [fr

Large-amplitude and narrow-band vibration phenomenon of a foursquare fix-supported flexible plate in a rigid narrow channel

Energy Technology Data Exchange (ETDEWEB)

Liu Lifang, E-mail: liu_lifang1106@yahoo.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Lu Daogang, E-mail: ludaogang@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Li Yang, E-mail: qinxiuyi@sina.com [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Zhang Pan, E-mail: zhangpan@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China); Niu Fenglei, E-mail: niufenglei@ncepu.edu.cn [School of Nuclear Science and Engineering, North China Electric Power University, Zhuxinzhuang, Dewai, Beijing 102206 (China)

2011-08-15

Highlights: > FIV of a foursquare fix-supported flexible plate exposed to axial flow was studied. > Special designed test section and advanced measuring equipments were adopted. > The narrow-band vibration phenomenon with large amplitude was observed. > Line of plate's vibration amplitude and flow rate was investigated. > The phenomenon and the measurement error were analyzed. - Abstract: An experiment was performed to analyze the flow-induced vibration behavior of a foursquare fix-supported flexible plate exposed to the axial flow within a rigid narrow channel. The large-amplitude and narrow-band vibration phenomenon was observed in the experiment when the flow velocity varied with the range of 0-5 m/s. The occurring condition and some characteristics of the large-amplitude and narrow-band vibrations were investigated.

Mutation of a vitelline membrane protein, BmEP80, is responsible for the silkworm "Ming" lethal egg mutant.

Science.gov (United States)

Chen, Anli; Gao, Peng; Zhao, Qiaoling; Tang, Shunming; Shen, Xingjia; Zhang, Guozheng; Qiu, Zhiyong; Xia, Dingguo; Huang, Yongping; Xu, Yunmin; He, Ningjia

2013-02-25

The egg stage is an important stage in the silkworm (Bombyx mori) life cycle. Normal silkworm eggs are usually short, elliptical, and laterally flattened, with a sometimes hollowed surface on the lateral side. However, the eggs laid by homozygous recessive "Ming" lethal egg mutants (l-e(m)) lose water and become concaved around 1h, ultimately exhibiting a triangular shape on the egg surfaces. We performed positional cloning, and narrowed down the region containing the gene responsible for the l-e(m) mutant to 360 kb on chromosome 10 using 2287 F(2) individuals. Using expression analysis and RNA interference, the best l-e(m) candidate gene was shown to be BmEP80. The results of the inverse polymerase chain reaction showed that an ~1.9 kb region from the 3' untranslated region of BmVMP23 to the forepart of BmEP80 was replaced by a >100 kb DNA fragment in the l-e(m) mutant. Several eggs laid by the normal moths injected with BmEP80 small interfering RNAs were evidently depressed and exhibited a triangular shape on the surface. The phenotype exhibited was consistent with the eggs laid by the l-e(m) mutant. Moreover, two-dimensional gel electrophoresis showed that the BmEP80 protein was expressed in the ovary from the 9th day of the pupa stage to eclosion in the wild-type silkworm, but was absent in the l-e(m) mutant. These results indicate that BmEP80 is responsible for the l-e(m) mutation. Copyright © 2012 Elsevier B.V. All rights reserved.

Parametric investigations of target normal sheath acceleration experiments

International Nuclear Information System (INIS)

Zani, Alessandro; Sgattoni, Andrea; Passoni, Matteo

2011-01-01

One of the most important challenges related to laser-driven ion acceleration research is to actively control some important ion beam features. This is a peculiar topic in the light of future possible technological applications. In the present work we make use of one theoretical model for target normal sheath acceleration in order to reproduce recent experimental parametric studies about maximum ion energy dependencies on laser parameters. The key role played by pulse energy and intensity is enlightened. Finally the effective dependence of maximum ion energy on intensity is evaluated using a combined theoretical approach, obtained by means of an analytical and a particle-in-cell numerical investigation.

Parametric investigations of target normal sheath acceleration experiments

Science.gov (United States)

Zani, Alessandro; Sgattoni, Andrea; Passoni, Matteo

2011-10-01

One of the most important challenges related to laser-driven ion acceleration research is to actively control some important ion beam features. This is a peculiar topic in the light of future possible technological applications. In the present work we make use of one theoretical model for target normal sheath acceleration in order to reproduce recent experimental parametric studies about maximum ion energy dependencies on laser parameters. The key role played by pulse energy and intensity is enlightened. Finally the effective dependence of maximum ion energy on intensity is evaluated using a combined theoretical approach, obtained by means of an analytical and a particle-in-cell numerical investigation.

Evolution of deformation velocity in narrowing for Zircaloy 2

Energy Technology Data Exchange (ETDEWEB)

Cetlin, P R [Minas Gerais Univ., Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica; Okuda, M Y [Goias Univ., Goiania (Brazil). Inst. de Matematica e Fisica

1980-09-01

Some studies on the deformation instability in strain shows that the differences in this instability may lead to localized narrowing or elongated narrowing, for Zircaloy-2. The variation of velocity deformation with the narrowing evolution is expected to be different for these two cases. The mentioned variation is discussed, a great difference in behavior having been observed for the case of localized narrowing.

The Swedish mutant barley collection

Energy Technology Data Exchange (ETDEWEB)

NONE

1989-07-01

Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

The Swedish mutant barley collection

International Nuclear Information System (INIS)

1989-01-01

Full text: The Swedish mutation research programme in barley began about 50 years ago and has mainly been carried out at Svaloev in co-operation with the institute of Genetics at the University of Lund. The collection has been produced from different Swedish high-yielding spring barley varieties, using the following mutagens: X-rays, neutrons, several organic chemical compounds such as ethyleneimine, several sulfonate derivatives and the inorganic chemical mutagen sodium azide. Nearly 10,000 barley mutants are stored in the Nordic Gene Bank and documented in databases developed by Udda Lundquist, Svaloev AB. The collection consists of the following nine categories with 94 different types of mutants: 1. Mutants with changes in the spike and spikelets; 2. Changes in culm length and culm composition; 3. Changes in growth types; 4. Physiological mutants; 5. Changes in awns; 6. Changes in seed size and shape; 7. Changes in leaf blades; 8. Changes in anthocyanin and colour; 9. Resistance to barley powdery mildew. Barley is one of the most thoroughly investigated crops in terms of induction of mutations and mutation genetics. So far, about half of the mutants stored at the Nordic Gene Bank, have been analysed genetically; They constitute, however, only a minority of the 94 different mutant types. The genetic analyses have given valuable insights into the mutation process but also into the genetic architecture of various characters. A number of mutants of two-row barley have been registered and commercially released. One of the earliest released, Mari, an early maturing, daylength neutral, straw stiff mutant, is still grown in Iceland. The Swedish mutation material has been used in Sweden, but also in other countries, such as Denmark, Germany, and USA, for various studies providing a better understanding of the barley genome. The collection will be immensely valuable for future molecular genetical analyses of clone mutant genes. (author)

Sealed coupling for an electrical heating conductor with coaxial sheath (pattern 1964)

International Nuclear Information System (INIS)

Arragon, Ph.; Aubert-Chevallier, R.; Gentil, J.; Seguin, M.; Vilcot, M.; Villiers, J.

1965-01-01

Many irradiation devices call for supplementary electrical heating which can provide a constant temperature. We describe a coupling whose high performance makes it possible for the sheathed electrical resistance to provide maximum power. Since this coupling is sealed and does not require special cooling, it may be placed in any position on the irradiation device. (authors) [fr

Apparatus for spot welding sheathed thermocouples to the inside of small-diameter tubes at precise locations

International Nuclear Information System (INIS)

Baucum, W.E.; Dial, R.E.

1976-01-01

Equipment and procedures used to spot weld tantalum- or stainless-steel-sheathed thermocouples to the inside diameter of Zircaloy tubing to meet the requirements of the Multirod Burst Test (MRBT) Program at ORNL are described. Spot welding and oxide cleaning tools were fabricated to remove the oxide coating on the Zircaloy tubing at local areas and spot weld four thermocouples separated circumferentially by 90 0 at any axial distribution desired. It was found necessary to apply a nickel coating to stainless-steel-sheathed thermocouples to obtain acceptable welds. The material and shape of the inner electrode and resistance between inner and outer electrodes were found to be critical parameters in obtaining acceptable welds

Mutants of alfalfa mosaic virus

International Nuclear Information System (INIS)

Roosien, J.

1983-01-01

In this thesis the isolation and characterization of a number of mutants of alfalfa mosaic virus, a plant virus with a coat protein dependent genome, is described. Thermo-sensitive (ts) mutants were selected since, at least theoretically, ts mutations can be present in all virus coded functions. It was found that a high percentage of spontaneous mutants, isolated because of their aberrant symptoms, were ts. The majority of these isolates could grow at the non-permissive temperature in the presence of a single wild type (wt) component. To increase the mutation rate virus preparations were treated with several mutagens. After nitrous acid treatment or irradiation with ultraviolet light, an increase in the level of mutations was observed. UV irradiation was preferred since it did not require large amounts of purified viral components. During the preliminary characterization of potential ts mutants the author also obtained one structural and several symptom mutants which were analysed further (chapter 7, 8 and 9). The properties of the ts mutants are described in chapter 3-7. (Auth.)

Prediction of etching-shape anomaly due to distortion of ion sheath around a large-scale three-dimensional structure by means of on-wafer monitoring technique and computer simulation

International Nuclear Information System (INIS)

Kubota, Tomohiro; Ohtake, Hiroto; Araki, Ryosuke; Yanagisawa, Yuuki; Samukawa, Seiji; Iwasaki, Takuya; Ono, Kohei; Miwa, Kazuhiro

2013-01-01

A system for predicting distortion of a profile during plasma etching was developed. The system consists of a combination of measurement and simulation. An ‘on-wafer sheath-shape sensor’ for measuring the plasma-sheath parameters (sheath potential and thickness) on the stage of the plasma etcher was developed. The sensor has numerous small electrodes for measuring sheath potential and saturation ion-current density, from which sheath thickness can be calculated. The results of the measurement show reasonable dependence on source power, bias power and pressure. Based on self-consistent calculation of potential distribution and ion- and electron-density distributions, simulation of the sheath potential distribution around an arbitrary 3D structure and the trajectory of incident ions from the plasma to the structure was developed. To confirm the validity of the distortion prediction by comparing it with experimentally measured distortion, silicon trench etching under chlorine inductively coupled plasma (ICP) was performed using a sample with a vertical step. It was found that the etched trench was distorted when the distance from the step was several millimetres or less. The distortion angle was about 20° at maximum. Measurement was performed using the on-wafer sheath-shape sensor in the same plasma condition as the etching. The ion incident angle, calculated as a function of distance from the step, successfully reproduced the experimentally measured angle, indicating that the combination of measurement by the on-wafer sheath-shape sensor and simulation can predict distortion of an etched structure. This prediction system will be useful for designing devices with large-scale 3D structures (such as those in MEMS) and determining the optimum etching conditions to obtain the desired profiles. (paper)

Primary radiotherapy in progressive optic nerve sheath meningiomas: a long-term follow-up study

NARCIS (Netherlands)

Saeed, P.; Blank, L.; Selva, D.; Wolbers, J.G.; Nowak, P.J.C.M.; Geskus, R.B.; Weis, E.; Mourits, M.P.; Rootman, J.

2010-01-01

Background/aims To report the outcome of primary radiotherapy in patients with progressive optic nerve sheath meningioma (ONSM). Methods The clinical records of all patients were reviewed in a retrospective, observational, multicentre study. Results Thirty-four consecutive patients were included.

Modelling of radio frequency sheath and fast wave coupling on the realistic ion cyclotron resonant antenna surroundings and the outer wall

Science.gov (United States)

Lu, L.; Colas, L.; Jacquot, J.; Després, B.; Heuraux, S.; Faudot, E.; Van Eester, D.; Crombé, K.; Křivská, A.; Noterdaeme, J.-M.; Helou, W.; Hillairet, J.

2018-03-01

In order to model the sheath rectification in a realistic geometry over the size of ion cyclotron resonant heating (ICRH) antennas, the self-consistent sheaths and waves for ICH (SSWICH) code couples self-consistently the RF wave propagation and the DC SOL biasing via nonlinear RF and DC sheath boundary conditions applied at plasma/wall interfaces. A first version of SSWICH had 2D (toroidal and radial) geometry, rectangular walls either normal or parallel to the confinement magnetic field B 0 and only included the evanescent slow wave (SW) excited parasitically by the ICRH antenna. The main wave for plasma heating, the fast wave (FW) plays no role on the sheath excitation in this version. A new version of the code, 2D SSWICH-full wave, was developed based on the COMSOL software, to accommodate full RF field polarization and shaped walls tilted with respect to B 0 . SSWICH-full wave simulations have shown the mode conversion of FW into SW occurring at the sharp corners where the boundary shape varies rapidly. It has also evidenced ‘far-field’ sheath oscillations appearing at the shaped walls with a relatively long magnetic connection length to the antenna, that are only accessible to the propagating FW. Joint simulation, conducted by SSWICH-full wave within a multi-2D approach excited using the 3D wave coupling code (RAPLICASOL), has recovered the double-hump poloidal structure measured in the experimental temperature and potential maps when only the SW is modelled. The FW contribution on the potential poloidal structure seems to be affected by the 3D effects, which was ignored in the current stage. Finally, SSWICH-full wave simulation revealed the left-right asymmetry that has been observed extensively in the unbalanced strap feeding experiments, suggesting that the spatial proximity effects in RF sheath excitation, studied for SW only previously, is still important in the vicinity of the wave launcher under full wave polarizations.

Narrow Networks on the Individual Marketplace in 2017.

Science.gov (United States)

Polski, Daniel; Weiner, Janet; Zhang, Yuehan

2017-09-01

This Issue Brief describes the breadth of physician networks on the ACA marketplaces in 2017. We find that the overall rate of narrow networks is 21%, which is a decline since 2014 (31%) and 2016 (25%). Narrow networks are concentrated in plans sold on state-based marketplaces, at 42%, compared to 10% of plans on federally-facilitated marketplaces. Issuers that have traditionally offered Medicaid coverage have the highest prevalence of narrow network plans at 36%, with regional/local plans and provider-based plans close behind at 27% and 30%. We also find large differences in narrow networks by state and by plan type.

Heterogeneous NiCo2O4@polypyrrole core/sheath nanowire arrays on Ni foam for high performance supercapacitors

Science.gov (United States)

Hu, Jing; Li, Minchan; Lv, Fucong; Yang, Mingyang; Tao, Pengpeng; Tang, Yougen; Liu, Hongtao; Lu, Zhouguang

2015-10-01

A novel heterogeneous NiCo2O4@PPy core/sheath nanowire arrays are directly grown on Ni foam involving three facile steps, hydrothermal synthesis and calcination of NiCo2O4 nanowire arrays and subsequent in-situ oxidative polymerization of polypyrrole (PPy). When investigated as binder- and conductive additive-free electrodes for supercapacitors (SCs) in 6 M KOH, the NiCo2O4@PPy core/sheath nanowire arrays exhibit high areal capacitance of 3.49 F cm-2 at a discharge current density of 5 mA cm-2, which is almost 1.5 times as much as the pristine NiCo2O4 (2.30 F cm-2). More importantly, it can remain 3.31 F cm-2 (94.8% retention) after 5000 cycles. The as-obtained electrode also displays excellent rate capability, whose areal capacitance can still remain 2.79 F cm-2 while the discharge current density is increased to 50 mA cm-2. The remarkable electrochemical performance is mainly attributed to the unique heterogeneous core/sheath nanowire-array architectures.

Assessments of sheath strain and fission gas release data from 20 years of power reactor fuel irradiations

International Nuclear Information System (INIS)

Purdy, P.L.; Manzer, A.M.; Hu, R.H.; Gibb, R.A.; Kohn, E.

1997-01-01

Over the past 20 years, many fuel elements or bundles discharged from Canadian CANDU power reactors have been examined in the AECL hot cells. The post-irradiation examination (PIE) database covers a wide range of operating conditions, from which fuel performance characteristics can be assessed. In the present analysis, a PIE database was compiled representing elements from a total of 129 fuel bundles, of which 26% (34 bundles) were confirmed to have one or more defective elements. This comprehensive database was assessed in terms of measured sheath strain and fission gas release (FGR) for intact elements, in an attempt to identify any changes in these parameters over the history of CANDU reactor operation. Results from this assessment indicate that, for the data that are typical of normal CANDU operating conditions, tensile sheath strain and FGR have remained within 0.5% and 8%, respectively. Those data beyond these ranges are from fuel operated under abnormal conditions, not representative of normal operation, and thus do not indicate a trend toward unexpected fuel behaviour. The distributions of the PIE measurements indicate that maximum expected sheath strains and FGR for normally operated fuel are 0.7% and 13%, respectively. (author)

Simulation of the influence high-frequency (2 MHz) capacitive gas discharge and magnetic field on the plasma sheath near a surface in hypersonic gas flow

International Nuclear Information System (INIS)

Schweigert, I. V.

2012-01-01

The plasma sheath near the surface of a hypersonic aircraft formed under associative ionization behind the shock front shields the transmission and reception of radio signals. Using two-dimensional kinetic particle-in-cell simulations, we consider the change in plasma-sheath parameters near a flat surface in a hypersonic flow under the action of electrical and magnetic fields. The combined action of a high-frequency 2-MHz capacitive discharge, a constant voltage, and a magnetic field on the plasma sheath allows the local electron density to be reduced manyfold.

The temperature and tension characteristics of the FBGs embedded in the polythene sheath of an optical cable

Science.gov (United States)

Chen, Guanghui; Zhao, Ming; Sha, Jianbo; Zhang, Jun; Wu, Bingyan; Lin, Chen; Zhang, Mingliang; Gao, Kan

2015-10-01

The five of FBG were embedded in the PE sheath of a tether optical cable, which has about 18mm diameter and 7000mm length. The temperature and tension characteristics of the FBGs embedded in the polythene (PE) sheath had been demonstrated quantitatively. The Bragg wavelength of the embedded FBG shift linearly with the change of pulling force loaded on the tether optical cable and its tension sensitivity is about 3.75 pm/kg. The results of temperature experiment suggest the embedded FBG have been sensitized by PE material, so that its temperature sensitivity increase from 9.37pm/°C to about 12.51pm/°C.

Genetic fingerprinting of mutant rose cultivars

Energy Technology Data Exchange (ETDEWEB)

Kumar, S; Prasad, K V; Singh, K P; Singh, A.P. [Division of Floriculture and Landscaping, Indian Agricultural Research Institute, Pusa, New Delhi (India)], E-mail: kvprasad66@gmail.com

2008-07-01

Six rose mutants evolved at the Indian Agricultural Research Institute, New Delhi from four parent cultivars were characterized based on RAPD markers. Contrary to the earlier findings our effort has conclusively proven that the RAPD markers are indeed robust tools to discern the mutants from their parents. Among 40 primers screened, 7 primers produced inconsistent banding pattern. The number of polymorphic bands varied between 4 (OPA 14) and 10 (OPA1) with an average of 6.5 bands per primer. The percentage polymorphism ranged from 62.5 (OPM 9) to 100 percent (OPA 1). Most of the primers produced monomorphic bands between parent and mutant rose cultivars. When primer OPA 2 was used a specific band of 2.5 kb was noticed in mutant cv. Pusa Urmil and cv. Pusa Abhishek but was absent in parent cv. Jantar Mantar. A polymorphic band of 750 bp was noticed in the parent Kiss of Fire and helped in differentiating the parent from its mutant when amplified with OPK 3. Primer OPS 16 produced discriminatory band of 800 bp in mutant cv. Pink Sport of Montezuma while it was absent in its parent cv. Montezuma. Another specific band of 650 bp was present in parent cv. Montezuma and absent in its mutant cv. Pink Sport of Montezuma signifying the uniqueness of the mutant. Primer OPM 5 brought out distinct polymorphism among the parent Jantar Mantar and its three mutants with absence of a specific band of 1.5 kb in the parent. The four parents and 6 mutants were divided into four distinct groups in the Dendogram constructed by UPGMA method. The most genetically similar cultivar among the 10 cultivars analyzed are Montezuma and its pink sport of Montezuma whereas Abhisarika a mutant of cv. Kiss of Fire was distinctly different and formed a separate cluster. (author)

Uniaxial Strain Induced Critical Current Degradation of Ag-Sheathed Bi-2212 Round Wire

NARCIS (Netherlands)

Dai, Chao; Qin, Jinggang; Liu, Bo; Liu, Peihang; Wu, Yu; Nijhuis, Arend; Zhou, Chao; Li, Chenshan; Hao, Qingbin; Liu, Sheng

2018-01-01

The critical current degradation of Bi-2212 Ag-sheathed round wire subjected to uniaxial strain was studied at 4.2 K in 14 T background field. The strains applied on the sample are both tension and compression. The additional tensile strain caused by the difference in thermal expansion between the

From one body mutant to one cell mutant. A progress of radiation breeding in crops

International Nuclear Information System (INIS)

Nagatomi, Shigeki

1996-01-01

An effective method was established to obtain non-chimeral mutants with wide spectrum of flower colors, regenerated from floral organs on which mutated sectors were come out on chronic irradiated plants. By this way, six mutant varieties of flower colors have been selected from one pink flower of chrysanthemum, and cultivated for cut-flower production. By the same method, 3 mutant varieties with small and spray type flowers were selected in Eustoma. Mutant varieties such as a rust disease resistant in sugarcane, 6 dwarfs in Cytisus and pure-white mushroom in velvet shank have been selected successively for short period. (J.P.N.)

Equilibrium properties of the plasma sheath with a magnetic field parallel to the wall

International Nuclear Information System (INIS)

Krasheninnikova, Natalia S.; Tang Xianzhu

2011-01-01

Motivated by the Magnetized Target Fusion (MTF), a systematic investigation of the equilibrium properties of a 1D plasma sheath with a magnetic field parallel to the wall was carried out using analytical theory and kinetic simulations. Initially uniform full Maxwellian plasma consisting of equal temperature collisionless electrons and ions is allowed to interact with a perfectly absorbing conducting wall, which charges positively due to large ions gyro-radii. The analysis of the steady-state plasma and field profiles reveals the importance of the relation between electron and ion thermal Larmor radii and plasma Debye length. In particular, the sheath width scaling, the details of the particle flows and the break-down of force balance components exhibit different behaviors in three possible regimes. Despite our primary motivation, the results in this paper can also be applicable to the divertor and the first wall of tokamaks.

Reconstruction of the time-averaged sheath potential profile in an argon RF plasma using the ion energy distribution

International Nuclear Information System (INIS)

Fivaz, M.; Brunner, S.; Schwarzenbach, W.; Howling, A.A.; Hollenstein, C.

1994-10-01

Charge-exchange collisions and radio-frequency excitation combine to give peaks in the ion energy distribution measured at the ground electrode of an argon plasma in a capacitive reactor. These peaks are used as a diagnostic to reconstruct the profile of the time-averaged potential in the sheath. Particle-In-Cell simulations show that the method is accurate. The method is applied to investigate the sheath thickness as a function of excitation frequency at constant plasma power. The time-averaged potential is found to be parabolic in both experimental measurements and numerical simulation. (author) 6 figs., 1 tab., 15 refs

Lead sheathing of ship hulls in the Roman period: Archaeometallurgical characterisation

Energy Technology Data Exchange (ETDEWEB)

Kahanov, Yaacov, E-mail: yak@research.haifa.ac.il [Leon Recanati Institute for Maritime Studies, University of Haifa, Haifa 31905 (Israel); Ashkenazi, Dana [Faculty of Engineering, Tel Aviv University, Ramat Aviv 69978 (Israel)

2011-08-15

An archaeometallurgical analysis of samples of lead sheathing from five ships of the Roman period was carried out in order to determine their composition and microstructure, and to obtain a better understanding of their manufacturing processes. The examinations included optical microscopy of metallographic cross-sections, microhardness tests, scanning electron microscopy, including energy dispersive spectroscopy, and X-ray photoelectron spectroscopy. The results show that the samples were all composed of lead covered with an oxide layer. The sheet thicknesses, microhardness values and microhardness distribution, as well as the grain size distribution, led to the conclusion that all of the sheets were produced by the same technology, using hammering, and were probably used for the same purpose. The presence of antimony was observed in the sample from the Roman ship from Caesarea, which may hint at an Italian (Sardinian) origin of the material, and perhaps of the ship. - Research Highlights: {yields} During the Roman period ship hulls were sheathed with lead. {yields} Five samples have been analysed for their characteristics and manufacturing process. {yields} The process was cold-working (strain-hardening) using hammering. {yields} The lead was open-casted on a flat stone, and later hammered at room temperature. {yields} Antimony in the Caesarea shipwreck may indicate an Italian origin of construction.

Assessing the permeability of the rat sciatic nerve epineural sheath against compounds with local anesthetic activity: an ex vivo electrophysiological study.

Science.gov (United States)

Kagiava, Alexia; Theophilidis, George

2013-10-01

Abstract Studies have shown that the sciatic nerve epineural sheath acts as a barrier and has a delaying effect on the diffusion of local anesthetics into the nerve fibers and endoneurium. The purpose of this work is to assess and to quantify the permeability of the epineural sheath. For this purpose, we isolated the rat sciatic nerve in a three-chamber recording bath that allowed us to monitor the constant in amplitude evoked nerve compound action potential (nCAP) for over 24 h. For nerves exposed to the compounds under investigation, we estimated the IT50 the time required to inhibit the nCAP to 50% of its initial value. For desheathed nerves, the half-vitality time was denoted as IT50(-) and for the ensheath normal nerves as IT50(+). There was no significant difference between the IT50 of desheathed and ensheathed nerves exposed to normal saline. The IT50(-) for nerves exposed to 40 mM lidocaine was 12.1 ± 0.95 s (n=14) and the IT50(+) was 341.4 ± 2.49 s (n=6). The permeability (P) coefficient of the epineural sheath was defined as the ratio IT50(+)/IT50(-). The P coefficient for 40 mM lidocaine and linalool was 28.2 and 3.48, correspondingly, and for 30 mM 2-heptanone was 4.87. This is an indication that the epineural sheath provided a stronger barrier against lidocaine, compared to natural local anesthetics, linalool and 2-heptanone. The methodology presented here is a useful tool for studying epineural sheath permeability to compounds with local anesthetic properties.

Induction of Mutants in Durum Wheat

International Nuclear Information System (INIS)

AL-Ubaidi, M.; Ibrahim, I.; AL-Hadithi, A.

2002-01-01

This investigation presents a breeding program for induction and development of a new genotype of durum wheat, resistant to lodging with high yield, by irradiation durum wheat hybrids (F2) with gamma rays 100 Gy, during 1990-1997 cultivation seasons. This program involves: induction of variability, selection evaluation of the mutants at three locations: Twaitha (Baghdad) Latifya ( Babylon) and Swari (Kutt). All mutants showed resistance to lodging and there was a significant reduction in plant height. Mutant SIXIZ-22 surpassed other mutants and its origin in lodging resistance and plant height (83.5,82.8 and 89.4 cm) in the three locations at generation M5 and M6, respectively. Also, there were significant differences between mutant and their origin in the number of spikes/M 2 and grain yild during the two successive generation. On the other hand, mutant IZxCO-105 surpassed other mutants in the number of spikes/M 2 (231.8,242.3 and 292) and grain yield (4336,3376 and 5232 kg/ha) in all testing location, respectively . (authors) 14 refs., 4 tabs

Thermographic determination of the sheath heat transmission coefficient in a high density plasma

NARCIS (Netherlands)

Berg, van den M.A.; Bystrov, K.E.; Pasquet, R.; Zielinski, J.J.; De Temmerman, G.C.

2013-01-01

Experiments were performed in the Pilot-PSI linear plasma device, to determine the sheath heat transmission coefficients in a high recycling regime under various conditions of density (1–20 × 1020 m-3) and plasma composition (H2, Ar, N2) relevant for the ITER divertor plasma. The 2D surface

QSOs with narrow emission lines

International Nuclear Information System (INIS)

Baldwin, J.A.; Mcmahon, R.; Hazard, C.; Williams, R.E.

1988-01-01

Observations of two new high-redshift, narrow-lined QSOs (NLQSOs) are presented and discussed together with observations of similar objects reported in the literature. Gravitational lensing is ruled out as a possible means of amplifying the luminosity for one of these objects. It is found that the NLQSOs have broad bases on their emission lines as well as the prominent narrow cores which define this class. Thus, these are not pole-on QSOs. The FWHM of the emission lines fits onto the smoothly falling tail of the lower end of the line-width distribution for complete QSO samples. The equivalent widths of the combined broad and narrow components of the lines are normal for QSOs of the luminosity range under study. However, the NLQSOs do show ionization differences from broader-lined QSOs; most significant, the semiforbidden C III/C IV intensity ratio is unusually low. The N/C abundance ratio in these objects is found to be normal; the Al/C abundance ratio may be quite high. 38 references

Association between QTLs and morphological traits toward sheath blight resistance in rice (Oryza sativa L.)

Science.gov (United States)

Hossain, Md Kamal; Jena, Kshirod Kumar; Bhuiyan, Md Atiqur Rahman; Wickneswari, Ratnam

2016-01-01

Sheath blight is considered the most significant disease of rice and causes enormous yield losses over the world. Breeding for resistant varieties is the only viable option to combat the disease efficiently. Seventeen diverged rice genotypes along with 17 QTL-linked SSR markers were evaluated under greenhouse conditions. Pearson’s correlation showed only the flag leaf angle had a significant correlation with sheath blight resistance under greenhouse screening. Multivariate analysis based on UPGMA clustering and principal component analysis (PCA) indicated that the flag leaf angle, flag leaf length, and plant compactness were significantly associated with the following SSR marker alleles: RM209 (116,130), RM202 (176), RM224 (126), RM257 (156), RM426 (175), and RM6971 (196), which are linked to the SB QTLs: QRlh11, qSBR11-3, qSBR11-1, qSBR9-1, qShB3-2, and qSB-9. A Mantel test suggested a weak relationship between the observed phenotypes and allelic variation patterns, implying the independent nature of morphological and molecular variations. Teqing and Tetep were found to be the most resistant cultivars. IR65482-4-136-2-2, MR219-4, and MR264 showed improved resistance potentials. These results suggest that the morphological traits and QTLs which have been found to associate with sheath blight resistance are a good choice to enhance resistance through pyramiding either 2 QTLs or QTLs and traits in susceptible rice cultivars. PMID:27795687

Utilizing Bacillus to inhibit the growth and infection by sheath blight pathogen, Rhizoctoniasolani in rice

Science.gov (United States)

Margani, R.; Hadiwiyono; Widadi, S.

2018-03-01

Rhizoctonia solani Kuhn is a common pathogen of rice. The pathogen causes sheath blight of rice. The pathogen can cause loss in the production of rice up to 45%. So far, the disease however is still poorly taken care of by the farmers and researchers, so the control measures is nearly never practiced by the farmers in the fields. It due to the unavailability of effective control method of the disease. Therefore, development to control the disease is important. Bacillus is one of popular bacteria which is effective as biological control agent of a lot of pathogens in plants, but it has not been used for control sheath blight in rice yet. The current researches were aimed to study the potential of Bacillus collected from healthy rice as candidates of biological control agent of the disease. The results showed that some isolates showed indications to inhibit significantly the growth and infection of the pathogen. We obtained at least five isolates of Bacillus collected from leaves, sheath, and stem of healthy rice fields. All of the isolates could effectively inhibit the growth of R. solani in vitro on potato dextrose medium at range 30.33-58.00%, whereas in vivo B05 isolate was the most effective in inhibiting the infection of pathogen at 30.43%. It was not significantly different (P≥0.05) to application of hexaconazol with dosage of 2 ml L-1.

Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

Science.gov (United States)

Kromdijk, Johannes; Ubierna, Nerea; Cousins, Asaph B; Griffiths, Howard

2014-07-01

Crop species with the C4 photosynthetic pathway are generally characterized by high productivity, especially in environmental conditions favouring photorespiration. In comparison with the ancestral C3 pathway, the biochemical and anatomical modifications of the C4 pathway allow spatial separation of primary carbon acquisition in mesophyll cells and subsequent assimilation in bundle-sheath cells. The CO2-concentrating C4 cycle has to operate in close coordination with CO2 reduction via the Calvin-Benson-Bassham (CBB) cycle in order to keep the C4 pathway energetically efficient. The gradient in CO2 concentration between bundle-sheath and mesophyll cells facilitates diffusive leakage of CO2. This rate of bundle-sheath CO2 leakage relative to the rate of phosphoenolpyruvate carboxylation (termed leakiness) has been used to probe the balance between C4 carbon acquisition and subsequent reduction as a result of environmental perturbations. When doing so, the correct choice of equations to derive leakiness from stable carbon isotope discrimination (Δ(13)C) during gas exchange is critical to avoid biased results. Leakiness responses to photon flux density, either short-term (during measurements) or long-term (during growth and development), can have important implications for C4 performance in understorey light conditions. However, recent reports show leakiness to be subject to considerable acclimation. Additionally, the recent discovery of two decarboxylating C4 cycles operating in parallel in Zea mays suggests that flexibility in the transported C4 acid and associated decarboxylase could also aid in maintaining C4/CBB balance in a changing environment. In this paper, we review improvements in methodology to estimate leakiness, synthesize reports on bundle-sheath leakiness, discuss different interpretations, and highlight areas where future research is necessary. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology

Ocular Biometrics of Myopic Eyes With Narrow Angles.

Science.gov (United States)

Chong, Gabriel T; Wen, Joanne C; Su, Daniel Hsien-Wen; Stinnett, Sandra; Asrani, Sanjay

2016-02-01

The purpose of this study was to compare the ocular biometrics between myopic patients with and without narrow angles. Patients with a stable myopic refraction (myopia worse than -1.00 D spherical equivalent) were prospectively recruited. Angle status was assessed using gonioscopy and biometric measurements were performed using an anterior segment optical coherence tomography and an IOLMaster. A total of 29 patients (58 eyes) were enrolled with 13 patients (26 eyes) classified as having narrow angles and 16 patients (32 eyes) classified as having open angles. Baseline demographics of age, sex, and ethnicity did not differ significantly between the 2 groups. The patients with narrow angles were on average older than those with open angles but the difference did not reach statistical significance (P=0.12). The central anterior chamber depth was significantly less in the eyes with narrow angles (P=0.05). However, the average lens thickness, although greater in the eyes with narrow angles, did not reach statistical significance (P=0.10). Refractive error, axial lengths, and iris thicknesses did not differ significantly between the 2 groups (P=0.32, 0.47, 0.15). Narrow angles can occur in myopic eyes. Routine gonioscopy is therefore recommended for all patients regardless of refractive error.

Intramyocardial arterial narrowing in dogs with subaortic stenosis.

Science.gov (United States)

Falk, T; Jönsson, L; Pedersen, H D

2004-09-01

Earlier studies have described intramyocardial arterial narrowing based on hyperplasia and hypertrophy of the vessel wall in dogs with subaortic stenosis (SAS). In theory, such changes might increase the risk of sudden death, as they seem to do in heart disease in other species. This retrospective pathological study describes and quantifies intramyocardial arterial narrowing in 44 dogs with naturally occurring SAS and in eight control dogs. The majority of the dogs with SAS died suddenly (n=27); nine had died or been euthanased with signs of heart failure and eight were euthanased without clinical signs. Dogs with SAS had significantly narrower intramyocardial arteries (Pdogs. Male dogs and those with more severe hypertrophy had more vessel narrowing (P=0.02 and P=0.02, respectively), whereas dogs with dilated hearts had slightly less pronounced arterial thickening (P=0.01). Arterial narrowing was not related to age, but fibrosis increased with age (P=0.047). Dogs that died suddenly did not have a greater number of arterial changes than other dogs with SAS. This study suggests that most dogs with SAS have intramyocardial arterial narrowing and that the risk of dying suddenly is not significantly related to the overall degree of vessel obliteration.

Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique

OpenAIRE

Ensinger, Wolfgang

1996-01-01

Influence of plasma density and plasma sheath dynamics on the ion implantation by plasma immersion technique / B. Rauschenbach ... - In: Nuclear instruments and methods in physics research. B. 113. 1996. S. 266-269

Root hair mutants of barley

International Nuclear Information System (INIS)

Engvild, K.C.; Rasmussen, K.

2005-01-01

Barley mutants without root hairs or with short or reduced root hairs were isolated among M 2 seeds of 'Lux' barley (Hordeum vulgare L.) after acidified sodium azide mutagenesis. Root hair mutants are investigated intensively in Arabidopsis where about 40 genes are known. A few root hair mutants are known in maize, rice, barley and tomato. Many plants without root hairs grow quite well with good plant nutrition, and mutants have been used for investigations of uptake of strongly bound nutrients like phosphorus, iron, zinc and silicon. Seed of 'Lux' barley (Sejet Plant Breeding, Denmark) were soaked overnight, and then treated with 1.5-millimolarsodium azide in 0.1 molar sodium phosphate buffer, pH 3, for 2.5 hours according to the IAEA Manual on Mutation Breeding (2nd Ed.). After rinsing in tap water and air-drying, the M 2 seeds were sown in the field the same day. Spikes, 4-6 per M 1 plant, were harvested. The mutation frequency was similar to that obtained with other barley cultivars from which low-phytate mutants were isolated [5]. Seeds were germinated on black filter paper in tap water for 3 or 4 days before scoring for root hair mutants

The growth of necks in fuel sheaths during high temperature transients in steam

International Nuclear Information System (INIS)

Hunt, C.E.L.

1980-02-01

In fuel sheaths oxidizing under stress during a high temperature transient, diametral strain is localized in regions where the oxide film cracks. As a result, the total strain in a tube depends on the number of cracks formed. The opening of a crack and the formation of the associated neck observed on the inner surface can be described by a sequence of slip steps. The initial width of the neck is equal to twice the tube wall thickness. If oxide cracks form at a spacing less than twice the wall thickness their associated necks interact. If the cracks are close together the combined neck will have a fairly smooth profile but as the crack spacing increases the combined neck profile will roughen. For a fuel sheath of the dimensions typically used in the Pickering Nuclear Generating Station (15.24 mm OD x 0.43 mm wall) any single crack and its associated neck can contribute up to about 5% diametral strain before penetration of the wall occurs. (auth)

Demyelinating polyneuropathy with focally folded myelin sheaths in a family of Miniature Schnauzer dogs.

Science.gov (United States)

Vanhaesebrouck, An E; Couturier, Jérôme; Cauzinille, Laurent; Mizisin, Andrew P; Shelton, G Diane; Granger, Nicolas

2008-12-15

A spontaneous demyelinating polyneuropathy in two young Miniature Schnauzer dogs was characterized clinically, electrophysiologically and histopathologically. Both dogs were related and a third dog, belonging to the same family, had similar clinical signs. On presentation, clinical signs were restricted to respiratory dysfunction. Electrophysiological tests showed a dramatic decrease in both motor and sensory nerve conduction velocities. Microscopic examination of peripheral nerve biopsies (light and electron microscopy, teased nerve fibers), showed that this neuropathy was characterized by segmental demyelination and focally folded myelin sheaths. Various clinical syndromes associated with tomacula or focal thickening of the myelin sheath of the peripheral nerves have been described in humans and shown to be caused by gene mutations affecting the myelin proteins, such as the hereditary neuropathy with liability to pressure palsies or the demyelinating forms of Charcot-Marie-Tooth disease. In animals, a tomaculous neuropathy has been reported in cattle and chickens but not in carnivores. Here we report a demyelinating peripheral neuropathy with tomacula in two Miniature Schnauzer dogs.

Highly Tunable Narrow Bandpass MEMS Filter

KAUST Repository

Hafiz, Md Abdullah Al

2017-07-07

We demonstrate a proof-of-concept highly tunable narrow bandpass filter based on electrothermally and electrostatically actuated microelectromechanical-system (MEMS) resonators. The device consists of two mechanically uncoupled clamped-clamped arch resonators, designed such that their resonance frequencies are independently tuned to obtain the desired narrow passband. Through the electrothermal and electrostatic actuation, the stiffness of the structures is highly tunable. We experimentally demonstrate significant percentage tuning (~125%) of the filter center frequency by varying the applied electrothermal voltages to the resonating structures, while maintaining a narrow passband of 550 ± 50 Hz, a stopband rejection of >17 dB, and a passband ripple ≤ 2.5 dB. An analytical model based on the Euler-Bernoulli beam theory is used to confirm the behavior of the filter, and the origin of the high tunability using electrothermal actuation is discussed.

Analytical solutions and particle simulations of cross-field plasma sheaths

International Nuclear Information System (INIS)

Gerver, M.J.; Parker, S.E.; Theilhaber, K.

1989-01-01

Particles simulations have been made of an infinite plasma slab, bounded by absorbing conducting walls, with a magnetic field parallel to the walls. The simulations have been either 1-D, or 2-D, with the magnetic field normal to the simulation plane. Initially, the plasma has a uniform density between the walls, and there is a uniform source of ions and electrons to replace particles lost to the walls. In the 1-D case, there is no diffusion of the particle guiding centers, and the plasma remains uniform in density and potential over most of the slab, with sheaths about a Debye length wide where the potential rises to the wall potential. In the 2-D case, the density profile becomes parabolic, going almost to zero at the walls, and there is a quasineutral presheath in the bulk of the plasma, in addition to sheaths near the walls. Analytic expressions are found for the density and potential profiles in both cases, including, in the 2-D case, the magnetic presheath due to finite ion Larmor radius, and the effects of the guiding center diffusion rate being either much less than or much grater than the energy diffusion rate. These analytic expressions are shown to agree with the simulations. A 1-D simulation with Monte Carlo guiding center diffusion included gives results that are good agreement with the much more expensive 2-D simulation. 17 refs., 10 figs

Laser-induced fluorescence measurements of argon ion velocities near the sheath boundary of an argon-xenon plasma

International Nuclear Information System (INIS)

Lee, Dongsoo; Severn, Greg; Oksuz, Lutfi; Hershkowitz, Noah

2006-01-01

The Bohm sheath criterion in single- and two-ion species plasma is studied with laser-induced fluorescence using a diode laser. Xenon is added to a low pressure unmagnetized dc hot filament argon discharge confined by surface multidipole magnetic fields. The Ar II transition at 668.614 nm is adopted for optical pumping to detect the fluorescence from the plasma and to measure the argon ion velocity distribution functions with respect to positions relative to a negatively biased boundary plate. The structures of the plasma sheath and presheath are measured by an emissive probe. The ion concentrations of the two-species in the bulk plasma are calculated from ion acoustic wave experiments. Results are compared with previous experiments of Ar-He plasmas in which the argon ions were the heavier ion species. Unlike the previous results, the argon speed is slower than its own Bohm velocity near the sheath-presheath boundary in the Ar-Xe plasma where argon ions are the lighter ion species. We argue that this result is consistent with the behaviour of the helium ion required by the generalized Bohm criterion in the previous experiments with Ar-He plasmas. Further, our results suggest that the measured argon ion speed approaches the ion sound speed of the system

Plasma sheath dynamics and parameters in focus and defocus conditions. Vol. 2

International Nuclear Information System (INIS)

Masoud, M.M.; Soliman, H.M.; El-Aragi, G.M.

1996-01-01

The study deals with the effect of the inner electrode polarity on the dynamic behaviour and parameters of plasma sheath in a coaxial discharge. The experimental investigations presented here were carried out in a coaxial plasma focus discharge device of mather geometry. It consisted of coaxial stainless steel hollow cylindrical electrodes with inner electrode 18.2 cm length and outer-electrode 31.5 cm length. The diameter of the inner and outer electrodes are 3.2 cm and 6.6 cm, respectively. The two electrodes are separated by a teflon disc at the breech. The outer electrode muzzle is connected to stainless steel expansion chamber of 23 cm length and 17 cm diameter. The discharge takes place in hydrogen gas with a base pressure of 1 torr. The experiments were conducted with 10 kV bank voltage, which corresponds to 100 K A peak discharge current. By using a double electric probe, It was found that the plasma electron density was higher near the negative electrode. Investigations using a miniature rogovsky coil have shown that, the radial and azimuthal current density increased with radial distance from negative electrode to positive electrode. The shape and the axial velocity of plasma sheath were measured using a magnetic probe. The experimental results indicate that, the plasma is thick near the negative electrode, in both cases of the outer or the inner electrode. Also it has been found that the axial plasma sheath velocity reaches its maximum value at the muzzle for positive and negative inner electrode. The magnitude of maximum axial velocity reaches 1.7 x 10 60 cm/s for positive inner electrode and decreased by 25% for negative inner electrode further investigations revealed that on interchanging the polarity from normal operation (positive inner electrode), it was found that with negative inner electrode the soft x-ray emission intensity dropped by three orders of magnitude from that with positive inner electrode. 9 figs

Plasma sheath dynamics and parameters in focus and defocus conditions. Vol. 2

Energy Technology Data Exchange (ETDEWEB)

Masoud, M M; Soliman, H M; El-Aragi, G M [Plasma Physics and Nuclear Fusion Department, Nuclear Research Centre, Atomic Energy Aurhority, Cairo (Egypt)

1996-03-01

The study deals with the effect of the inner electrode polarity on the dynamic behaviour and parameters of plasma sheath in a coaxial discharge. The experimental investigations presented here were carried out in a coaxial plasma focus discharge device of mather geometry. It consisted of coaxial stainless steel hollow cylindrical electrodes with inner electrode 18.2 cm length and outer-electrode 31.5 cm length. The diameter of the inner and outer electrodes are 3.2 cm and 6.6 cm, respectively. The two electrodes are separated by a teflon disc at the breech. The outer electrode muzzle is connected to stainless steel expansion chamber of 23 cm length and 17 cm diameter. The discharge takes place in hydrogen gas with a base pressure of 1 torr. The experiments were conducted with 10 kV bank voltage, which corresponds to 100 K A peak discharge current. By using a double electric probe, It was found that the plasma electron density was higher near the negative electrode. Investigations using a miniature rogovsky coil have shown that, the radial and azimuthal current density increased with radial distance from negative electrode to positive electrode. The shape and the axial velocity of plasma sheath were measured using a magnetic probe. The experimental results indicate that, the plasma is thick near the negative electrode, in both cases of the outer or the inner electrode. Also it has been found that the axial plasma sheath velocity reaches its maximum value at the muzzle for positive and negative inner electrode. The magnitude of maximum axial velocity reaches 1.7 x 10{sup 60} cm/s for positive inner electrode and decreased by 25% for negative inner electrode further investigations revealed that on interchanging the polarity from normal operation (positive inner electrode), it was found that with negative inner electrode the soft x-ray emission intensity dropped by three orders of magnitude from that with positive inner electrode. 9 figs.

Gibberellin-regulated gene in the basal region of rice leaf sheath encodes basic helix-loop-helix transcription factor.

Science.gov (United States)

Komatsu, Setsuko; Takasaki, Hironori

2009-07-01

Genes regulated by gibberellin (GA) during leaf sheath elongation in rice seedlings were identified using the transcriptome approach. mRNA from the basal regions of leaf sheaths treated with GA3 was analyzed by high-coverage gene expression profiling. 33,004 peaks were detected, and 30 transcripts showed significant changes in the presence of GA3. Among these, basic helix-loop-helix transcription factor (AK073385) was significantly upregulated. Quantitative PCR analysis confirmed that expression of AK073385 was controlled by GA3 in a time- and dose-dependent manner. Basic helix-loop-helix transcription factor (AK073385) is therefore involved in the regulation of gene expression by GA3.

Isozyme differences in barley mutants

International Nuclear Information System (INIS)

AI-Jibouri, A.A.M.; Dham, K.M.

1990-01-01

Full text: Thirty mutants (M 11 ) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

Simulation study of wave phenomena from the sheath region in single frequency capacitively coupled plasma discharges; field reversals and ion reflection

Energy Technology Data Exchange (ETDEWEB)

Sharma, S.; Turner, M. M. [National Centre for Plasma Science and Technology, School of Physical Sciences, Dublin City University, Dublin 9 (Ireland)

2013-07-15

Capacitively coupled radio-frequency (RF) discharges have great significance for industrial applications. Collisionless electron heating in such discharges is important, and sometimes is the dominant mechanism. This heating is usually understood to originate in a stochastic interaction between electrons and the electric fields. However, other mechanisms may also be important. There is evidence of wave emission with a frequency near the electron plasma frequency, i.e., ω{sub pe}, from the sheath region in collisionless capacitive RF discharges. This is the result of a progressive breakdown of quasi-neutrality close to the electron sheath edge. These waves are damped in a few centimeters during their propagation from the sheath towards the bulk plasma. The damping occurs because of the Landau damping or some related mechanism. This research work reports that the emission of waves is associated with a field reversal during the expanding phase of the sheath. Trapping of electrons near to this field reversal region is observed. The amplitude of the wave increases with increasing RF current density amplitude J(tilde sign){sub 0} until some maximum is reached, beyond which the wave diminishes and a new regime appears. In this new regime, the density of the bulk plasma suddenly increases because of ion reflection, which occurs due to the presence of strong field reversal near sheath region. Our calculation shows that these waves are electron plasma waves. These phenomena occur under extreme conditions (i.e., higher J(tilde sign){sub 0} than in typical experiments) for sinusoidal current waveforms, but similar effects may occur with non-sinusoidal pulsed waveforms for conditions of experimental interest, because the rate of change of current is a relevant parameter. The effect of electron elastic collisions on plasma waves is also investigated.

Ascertainment of the effect of differential growth rates of mutants on observed mutant frequencies in X-irradiated mammalian cells

International Nuclear Information System (INIS)

Knaap, A.G.A.C.; Simons, J.W.I.M.

1983-01-01

As it is not known to what extent differential growth rates of induced mutants lead to over- and under-representation of mutants in treated populations and thereby affect the determination of mutant frequencies, the mutation induction in X-irradiated L5178Y mouse lymphoma cells was determined via two methods. The first method involves the standard protocol which may suffer from the effect of differential growth rates, while the second method is based upon the fluctuation test in which the differential growth rates can be actually measured. It appeared that the standard protocol led to a mutant frequency that was similar to the mutant frequency determined in the fluctuation test. Therefore, the standard protocol appears to lead to only a minor under-estimation if any. Substantial heterogeneity in growth rates of induced mutants was observed, but the mutants with a selective advantage appear largely to compensate for the mutants that are lost because of selective disadvantage. It was calculated that the chance for isolating the same mutant twice from a treated population had been increased 2.2-fold because of the observed differential growth rates. (orig./AJ)

Plasma sheath physics and dose uniformity in enhanced glow discharge plasma immersion ion implantation and deposition

International Nuclear Information System (INIS)

Li Liuhe; Li Jianhui; Kwok, Dixon T. K.; Chu, Paul K.; Wang Zhuo

2009-01-01

Based on the multiple-grid particle-in-cell code, an advanced simulation model is established to study the sheath physics and dose uniformity along the sample stage in order to provide the theoretical basis for further improvement of enhanced glow discharge plasma immersion ion implantation and deposition. At t=7.0 μs, the expansion of the sheath in the horizontal direction is hindered by the dielectric cage. The electron focusing effect is demonstrated by this model. Most of the ions at the inside wall of the cage are implanted into the edge of the sample stage and a relatively uniform ion fluence distribution with a large peak is observed at the end. Compared to the results obtained from the previous model, a higher implant fluence and larger area of uniformity are disclosed.

Dose evaluation of narrow-beam

International Nuclear Information System (INIS)

Goto, Shinichi

1999-01-01

Reliability of the dose from the narrow photon beam becomes more important since the single high-dose rate radiosurgery becoming popular. The dose evaluation for the optimal dose is difficult due to absence of lateral electronic equilibrium. Data necessary for treatment regimen are TMR (tissue maximum ratio), OCR (off center ratio) and S c,p (total scatter factor). The narrow-beam was 10 MV X-ray from Varian Clinac 2100C equipped with cylindrical Fischer collimator CBI system. Detection was performed by Kodak XV-2 film, a PTW natural diamond detector M60003, Scanditronics silicon detector EDD-5 or Fujitec micro-chamber FDC-9.4C. Phantoms were the water equivalent one (PTW, RW3), water one (PTW, MP3 system) and Wellhofer WP600 system. Factors above were actually measured to reveal that in the dose evaluation of narrow photon beam, TMR should be measured by micro-chamber, OCR, by film, and S c,p , by the two. The use of diamond detector was recommended for more precise measurement and evaluation of the dose. The importance of water phantom in the radiosurgery system was also shown. (K.H.)

Randomized clinical trial of biodegradeable intraluminal sheath to prevent anastomotic leak after stapled colorectal anastomosis

NARCIS (Netherlands)

Bakker, I S; Morks, A N; Ten Cate Hoedemaker, H O; Burgerhof, J G M; Leuvenink, H G; van Praagh, J B; Ploeg, R J; Havenga, K

Background: Anastomotic leakage is a potential major complication after colorectal surgery. The C-seal was developed to help reduce the clinical leakage rate. It is an intraluminal sheath that is stapled proximal to a colorectal anastomosis, covering it intraluminally and thus preventing intestinal

[The transrectus sheath preperitoneal procedure: a safe, effective and cheap surgical approach to inguinal hernia?

NARCIS (Netherlands)

Prins, M.W.; Voropai, D.A.; Laarhoven, C.J.H.M. van; Akkersdijk, W.L.

2013-01-01

The main complication of surgery for inguinal hernia is chronic postoperative pain. This is often reported following the Lichtenstein procedure. A new, open surgical technique for the repair of inguinal hernia has been developed. This procedure is called the transrectus sheath preperitoneal

Isozyme differences in barley mutants

Energy Technology Data Exchange (ETDEWEB)

AI-Jibouri, A A.M.; Dham, K M [Department of Botany, Nuclear Research Centre, Baghdad (Iraq)

1990-01-01

Full text: Thirty mutants (M{sub 11}) of barley (Hordeum vulgare L.) induced by physical and chemical mutagens were analysed for isozyme composition using polyacrylamide gel electrophoresis. Results show that these mutants were different in the isozymes leucine aminopeptidase, esterase and peroxidase. The differences included the number of forms of each enzyme, relative mobility value and their intensity on the gel. Glutamate oxaloacetate transaminase isozyme was found in six molecular forms and these forms were similar in all mutants. (author)

The Efficacy of the Coaxial Technique Using a 6-Fr Introducer Sheath in Stent Placement for Treating the Obstructions Proximal to the Descending Colon