Sheath energy transmission in a collisional plasma with collisionless sheath

DOE PAGES

Tang, Xian-Zhu; Guo, Zehua

2015-10-16

Sheath energy transmission governs the plasma energy exhaust onto a material surface. The ion channel is dominated by convection, but the electron channel has a significant thermal conduction component, which is dominated by the Knudsen layer effect in the presence of an absorbing wall. First-principle kinetic simulations also reveal a robustly supersonic sheath entry flow. The ion sheath energy transmission and the sheath potential are accurately predicted by a sheath model of truncated bi-Maxwellian electron distribution. The electron energy transmission is further enhanced by a parallel heat flux of the perpendicular degrees of freedom.

Starch Accumulation in the Bundle Sheaths of C3 Plants: A Possible Pre-Condition for C4 Photosynthesis.

PubMed

Miyake, Hiroshi

2016-05-01

C4 plants have evolved >60 times from their C3 ancestors. C4 photosynthesis requires a set of closely co-ordinated anatomical and biochemical characteristics. However, it is now recognized that the evolution of C4 plants requires fewer changes than had ever been considered, because of the genetic, biochemical and anatomical pre-conditions of C3 ancestors that were recruited into C4 photosynthesis. Therefore, the pre-conditions in C3 plants are now being actively investigated to clarify the evolutionary trajectory from C3 to C4 plants and to engineer C4 traits efficiently into C3 crops. In the present mini review, the anatomical characteristics of C3 and C4 plants are briefly reviewed and the importance of the bundle sheath for the evolution of C4 photosynthesis is described. For example, while the bundle sheath of C3 rice plants accumulates large amounts of starch in the developing leaf blade and at the lamina joint of the mature leaf, the starch sheath function is also observed during leaf development in starch accumulator grasses regardless of photosynthetic type. The starch sheath function of C3 plants is therefore also implicated as a possible pre-condition for the evolution of C4 photosynthesis. The phylogenetic relationships between the types of storage carbohydrates and of photosynthesis need to be clarified in the future. © The Author 2016. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please email: journals.permissions@oup.com.

The HsiB1C1 (TssB-TssC) Complex of the Pseudomonas aeruginosa Type VI Secretion System Forms a Bacteriophage Tail Sheathlike Structure

PubMed Central

Lossi, Nadine S.; Manoli, Eleni; Förster, Andreas; Dajani, Rana; Pape, Tillmann; Freemont, Paul; Filloux, Alain

2013-01-01

Protein secretion systems in Gram-negative bacteria evolved into a variety of molecular nanomachines. They are related to cell envelope complexes, which are involved in assembly of surface appendages or transport of solutes. They are classified as types, the most recent addition being the type VI secretion system (T6SS). The T6SS displays similarities to bacteriophage tail, which drives DNA injection into bacteria. The Hcp protein is related to the T4 bacteriophage tail tube protein gp19, whereas VgrG proteins structurally resemble the gp27/gp5 puncturing device of the phage. The tube and spike of the phage are pushed through the bacterial envelope upon contraction of a tail sheath composed of gp18. In Vibrio cholerae it was proposed that VipA and VipB assemble into a tail sheathlike structure. Here we confirm these previous data by showing that HsiB1 and HsiC1 of the Pseudomonas aeruginosa H1-T6SS assemble into tubules resulting from stacking of cogwheel-like structures showing predominantly 12-fold symmetry. The internal diameter of the cogwheels is ∼100 Å, which is large enough to accommodate an Hcp tube whose external diameter has been reported to be 85 Å. The N-terminal 212 residues of HsiC1 are sufficient to form a stable complex with HsiB1, but the C terminus of HsiC1 is essential for the formation of the tubelike structure. Bioinformatics analysis suggests that HsiC1 displays similarities to gp18-like proteins in its C-terminal region. In conclusion, we provide further structural and mechanistic insights into the T6SS and show that a phage sheathlike structure is likely to be a conserved element across all T6SSs. PMID:23341461

Bundle-sheath leakiness in C4 photosynthesis: a careful balancing act between CO2 concentration and assimilation.

PubMed

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

Sheaths: A Comparison of Magnetospheric, ICME, and Heliospheric Sheaths

NASA Technical Reports Server (NTRS)

Sibeck, D. G.; Richardson, J. D.; Liu, W.

2007-01-01

When a supersonic flow encounters an obstacles, shocks form to divert the flow around the obstacle. The region between the shock and the obstacle is the sheath, where the supersonic flow is compressed, heated, decelerated, and deflected. Supersonic flows, obstacles, and thus sheaths are observed on many scales throughout the Universe. We compare three examples seen in the heliosphere, illustrating the interaction of the solar wind with obstacles of three very different scales lengths. Magnetosheaths form behind planetary bow shocks on scales ranging from tens to 100 planetary radii. ICME sheath form behind shocks driven by solar disturbances on scale lengths of a few to tens of AU. The heliosheath forms behind the termination shock due to the obstacle presented by the interstellar medium on scale lengths of tens to a hundred AU. Despite this range in scales some common features have been observed. Magnetic holes, possibly due to mirror mode waves, have been observed in all three of these sheaths. Plasma depletion layers are observed in planetary and ICME sheaths. Other features observed in some sheaths are wave activity (ion cyclotron, plasma), energetic particles, transmission of Alfven waves/shocks, tangential discontinuities turbulence behind quasi-parallel shocks, standing slow mode waves, and reconnection on the obstacle boundary. We compare these sheath regions, discussing similarities and differences and how these may relate to the scale lengths of these regions.

Conceptual Design of Tail-Research EXperiment (T-REX) on Space Plasma Environment Research Facility

NASA Astrophysics Data System (ADS)

Xiao, Qingmei; Wang, Xiaogang; E, Peng; Shen, Chao; Wang, Zhibin; Mao, Aohua; Xiao, Chijie; Ding, Weixing; Ji, Hantao; Ren, Yang

2016-10-01

Space Environment Simulation Research Infrastructure (SESRI), a scientific project for a major national facility of fundamental researches, has recently been launched at Harbin Institute of Technology (HIT). The Space Plasma Environment Research Facility (SPERF) for simulation of space plasma environment is one of the components of SESRI. It is designed to investigate fundamental issues in space plasma environment, such as energetic particles transportation and the interaction with waves in magnetosphere, magnetic reconnection at magnetopause and magnetotail, etc. Tail-Research Experiment (T-REX) is part of the SPERF for laboratory studies of space physics relevant to tail reconnection and dipolarization process. T-REX is designed to carry out two kinds of experiments: the tail plasmamoid for magnetic reconnection and magnetohydrodynamic waves excited by high speed plasma jet. In this presentation, the scientific goals and experimental plans for T-REX together with the means applied to generate the plasma with desired parameters are reviewed. Two typical scenarios of T-REX with operations of plasma sources and various magnetic configurations to study specific physical processes in space plasmas will also be presented.

Side-welded fast response sheathed thermocouple

DOEpatents

Carr, Kenneth R.

1981-01-01

A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4-5 times faster and the thermal shock and cycling capabilities are substantially improved.

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

NASA Astrophysics Data System (ADS)

Tsui, C. K.; Boedo, J. A.; Stangeby, P. C.; TCV Team

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 lp, and the model is thus referred to as the "perimeter sheath expansion method." lp 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 = Vf.

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

PubMed

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 .

Side-welded fast response sheathed thermocouple

DOEpatents

Carr, K.R.

A method of fabricating the measuring junction of a grounded-junction sheathed thermocouple to obtain fast time response and good thermal cycling performance is provided. Slots are tooled or machined into the sheath wall at the measuring junction, the thermocouple wires are laser-welded into the slots. A thin metal closure cap is then laser-welded over the end of the sheath. Compared to a conventional grounded-junction thermocouple, the response time is 4 to 5 times faster and the thermal shock and cycling capabilities are substantially improved.

Heterogeneous NiCo2O4@polypyrrole core/sheath nanowire arrays on Ni foam for high performance supercapacitors

NASA Astrophysics Data System (ADS)

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.

Transport current density at temperatures up to 25 K of Cu/Ag composite sheathed 122-type tapes and wires

NASA Astrophysics Data System (ADS)

Liu, Shifa; Lin, Kaili; Yao, Chao; Zhang, Xianping; Dong, Chiheng; Wang, Dongliang; Awaji, Satoshi; Kumakura, Hiroaki; Ma, Yanwei

2017-11-01

The fabrication of iron-based superconductors with high transport critical current density (J c) and low cost is a crucial determinant of whether they can be used for practical applications. In this paper, Cu/Ag composite sheathed Sr0.6K0.4Fe2As2 (Sr122) tapes and Ba0.6K0.4Fe2As2 (Ba122) round wires were fabricated via an ex situ powder-in-tube method and heat-treated by the hot pressing and hot isostatic pressing process respectively. In order to thoroughly reveal the application potential of Cu/Ag composite sheathed ‘122’ iron pnictide superconductors, transport J c of tapes and wires in high fields at temperatures up to 25 K was measured. High transport J c of 4.4 × 104 A cm-2 at 4.2 K and 3.6 × 103 A cm-2 at 20 K in 10 T was achieved in Cu/Ag composite sheathed Sr122 tapes. Transport J c of Ba122 wires is 9.4 × 103 A cm-2 at 4.2 K and 1.9 × 103 A cm-2 at 20 K in 10 T. These results demonstrate the great potential of Cu/Ag composite sheathed ‘122’ iron pnictide superconducting tapes and wires for high-field applications at intermediate temperatures around 20 K, which can be easily obtained by using cryocoolers.

Plasma-Sheath Model

NASA Astrophysics Data System (ADS)

Riemann, Karl-Ulrich

2012-10-01

In typical gas discharges a quasineutral plasma is shielded from a negativ absorbing wall by a thin positive sheath that is nearly planar and collision-free. The subdivision of ``plasma'' and ``sheath'' was introduced by Langmuir and is based on a small ratio of the electron Debye lenghth λD to the dominant competing characteristic plasma length l. Depending on the special conditions, l may represent, e.g., the plasma extension, the ionization length, the ion mean free path, the ion gyro radius, or a geometric length. Strictly speaking, this subdivion is possible only in the asymptotic limit λD/l->0. The asymptotic analysis results in singularities at the ``sheath edge'' closely related to the ``Bohm criterion.'' Due to these singularities a direct smooth matching of the separate plasma and sheath soltions is not possible. To obtain a consistent smooth transition, the singular sheath edge must be bridged by an additinal narrow ``intermediate'' model zone accounting both for plasma processes (e.g., collisions) and for the first build up of space charge. Due to this complexity and to different interpretations of the ``classical'' papers by Langmuir and Bohm, the asymptotic plasma-sheath concept and the definition of the sheath edge were questioned and resulted in controversies during the last two decades. We discuss attempts to re-define the sheath edge, to account for finite values of λD/l in the Bohm criterion, and demonstrate the consistent matching of plasma and sheath. The investigations of the plasma-sheath transition discussed so far are based on a simplified fluid analysis that cannot account for the essential inhomogeneity of the boundary layer and for the dominant role of slow ions in space charge formation. Therefore we give special emphasis to the kinetic theory of the plasma-sheath transition. Unfortunately this approach results in an additional mathematical difficulty caused by ions with zero velocity. We discuss attempts to avoid this singularity by

Enhanced t -3/2 long-time tail for the stress-stress time correlation function

NASA Astrophysics Data System (ADS)

Evans, Denis J.

1980-01-01

Nonequilibrium molecular dynamics is used to calculate the spectrum of shear viscosity for a Lennard-Jones fluid. The calculated zero-frequency shear viscosity agrees well with experimental argon results for the two state points considered. The low-frequency behavior of shear viscosity is dominated by an ω 1/2 cusp. Analysis of the form of this cusp reveals that the stress-stress time correlation function exhibits a t -3/2 "long-time tail." It is shown that for the state points studied, the amplitude of this long-time tail is between 12 and 150 times larger than what has been predicted theoretically. If the low-frequency results are truly asymptotic, they imply that the cross and potential contributions to the Kubo-Green integrand for shear viscosity exhibit a t -3/2 long-time tail. This result contradicts the established theory of such processes.

Application of three tailing-based composites in treating comprehensive electroplating wastewater.

PubMed

Liu, Hongbo; Zhu, Mengling; Gao, Saisai

2014-01-01

Heavy metals and chemical oxygen demand (COD) are major challenging pollutants for most electroplating wastewater treatment plants. A novel composite material, prepared with a mixture of calcium and sodium compounds and tailings, was simply mixed by ratios and used to treat a comprehensive electroplating wastewater with influent COD, total copper (T-Cu), and total nickel (T-Ni) respectively as 690, 4.01, and 20.60 mg/L on average. Operational parameters, i.e. the contact time, pH, mass ratio of calcium and sodium compounds and tailings, were optimized as 30 min, 10.0, and 4:2:1. Removal rates for COD, T-Cu, and T-Ni could reach 71.8, 90.5, and 98.1%, respectively. No significant effect of initial concentrations on removal of T-Cu and T-Ni was observed for the composite material. The adsorption of Cu(II) and Ni(II) on the material fitted Langmuir and Freundlich isotherms respectively. Weight of waste sludge from the calcium/sodium-tailing system after reaction was 10% less than that from the calcium-tailing system. The tailing-based composite is cost-effective in combating comprehensive electroplating pollution, which shows a possibility of applying the tailings in treating electroplating wastewater.

Structure and immunocytochemical localization of photosynthetic enzymes in the lamina joint and sheath pulvinus of the C4 grass Arundinella hirta.

PubMed

Wakayama, Masataka; Ohnishi, Jun-ichi; Ueno, Osamu

2013-03-01

The C(4) grass Arundinella hirta exhibits a unique C(4) anatomy, with isolated Kranz cells (distinctive cells) and C(4)-type expression of photosynthetic enzymes in the leaf sheath and stem as well as in the leaf blade. The border zones between these organs are pale green. Those between the leaf blade and sheath and between the sheath and stem are called the lamina joint and sheath pulvinus, respectively, and are involved in gravity sensing. We investigated the structure and localization of C(3) and C(4) photosynthetic enzymes in these tissues. In both zones the epidermis lacked stomata. The inner tissue was composed of parenchyma cells and vascular bundles. The parenchyma cells were densely packed with small intercellular spaces and contained granal chloroplasts with large starch grains. No C(4)-type cellular differentiation was recognized. Western blot analysis showed that the lamina joint and pulvinus accumulated substantial amounts of phosphoenolpyruvate carboxylase (PEPC), pyruvate,Pi dikinase (PPDK), and ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco). Immunogold electron microscopy revealed PEPC in the cytosol and both PPDK and rubisco in the chloroplasts of parenchyma cells, suggesting the occurrence of C(3) and C(4) enzymes within a single type of chlorenchyma cell. These data indicate that the lamina joint and pulvinus have unique expression patterns of C(3) and C(4) enzymes, unlike those in C(4)-type anatomy.

Shifts in microbial community composition and function in the acidification of a lead/zinc mine tailings.

PubMed

Chen, Lin-Xing; Li, Jin-Tian; Chen, Ya-Ting; Huang, Li-Nan; Hua, Zheng-Shuang; Hu, Min; Shu, Wen-Sheng

2013-09-01

In an attempt to link the microbial community composition and function in mine tailings to the generation of acid mine drainage, we simultaneously explored the geochemistry and microbiology of six tailings collected from a lead/zinc mine, i.e. primary tailings (T1), slightly acidic tailings (T2), extremely acidic tailings (T3, T4 and T5) and orange-coloured oxidized tailings (T6). Geochemical results showed that the six tailings (from T1 to T6) likely represented sequential stages of the acidification process of the mine tailings. 16S rRNA pyrosequencing revealed a contrasting microbial composition between the six tailings: Proteobacteria-related sequences dominated T1-T3 with relative abundance ranging from 56 to 93%, whereas Ferroplasma-related sequences dominated T4-T6 with relative abundance ranging from 28 to 58%. Furthermore, metagenomic analysis of the microbial communities of T2 and T6 indicated that the genes encoding key enzymes for microbial carbon fixation, nitrogen fixation and sulfur oxidation in T2 were largely from Thiobacillus and Acidithiobacillus, Methylococcus capsulatus, and Thiobacillus denitrificans respectively; while those in T6 were mostly identified in Acidithiobacillus and Leptospirillum, Acidithiobacillus and Leptospirillum, and Acidithiobacillus respectively. The microbial communities in T2 and T6 harboured more genes suggesting diverse metabolic capacities for sulfur oxidation/heavy metal detoxification and tolerating low pH respectively. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

46 CFR 111.05-7 - Armored and metallic sheathed cable.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 4 2011-10-01 2011-10-01 false Armored and metallic sheathed cable. 111.05-7 Section 111.05-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... Armored and metallic sheathed cable. When installed, the metallic armor or sheath must meet the...

46 CFR 111.05-7 - Armored and metallic sheathed cable.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 4 2010-10-01 2010-10-01 false Armored and metallic sheathed cable. 111.05-7 Section 111.05-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... Armored and metallic sheathed cable. When installed, the metallic armor or sheath must meet the...

46 CFR 111.05-7 - Armored and metallic sheathed cable.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 4 2014-10-01 2014-10-01 false Armored and metallic sheathed cable. 111.05-7 Section 111.05-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... Armored and metallic sheathed cable. When installed, the metallic armor or sheath must meet the...

46 CFR 111.05-7 - Armored and metallic sheathed cable.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 4 2013-10-01 2013-10-01 false Armored and metallic sheathed cable. 111.05-7 Section 111.05-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... Armored and metallic sheathed cable. When installed, the metallic armor or sheath must meet the...

46 CFR 111.05-7 - Armored and metallic sheathed cable.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 4 2012-10-01 2012-10-01 false Armored and metallic sheathed cable. 111.05-7 Section 111.05-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING... Armored and metallic sheathed cable. When installed, the metallic armor or sheath must meet the...

APPARATUS FOR SHEATHING RODS

DOEpatents

Ford, W.K.; Wyatt, M.; Plail, S.

1961-08-01

An arrangement is described for sealing a solid body of nuclear fuel, such as a uranium metal rod, into a closelyfitting thin metallic sheath with an internal atmosphere of inert gas. The sheathing process consists of subjecting the sheath, loaded with the nuclear fuel body, to the sequential operations of evacuation, gas-filling, drawing (to entrap inert gas and secure close contact between sheath and body), and sealing. (AEC)

Glancing angle RF sheaths

NASA Astrophysics Data System (ADS)

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

2013-10-01

RF sheaths occur in tokamaks when ICRF waves encounter conducting boundaries. The sheath plays an important role in determining the efficiency of ICRF heating, the impurity influxes from the edge plasma, and the plasma-facing component damage. An important parameter in sheath theory is the angle θ between the equilibrium B field and the wall. Recent work with 1D and 2D sheath models has shown that the rapid variation of θ around a typical limiter can lead to enhanced sheath potentials and localized power deposition (hot spots) when the B field is near glancing incidence. The physics model used to obtain these results does not include some glancing-angle effects, e.g. possible modification of the angular dependence of the Child-Langmuir law and the role of the magnetic pre-sheath. Here, we report on calculations which explore these effects, with the goal of improving the fidelity of the rf sheath BC used in analytical and numerical calculations. Work supported by US DOE grants DE-FC02-05ER54823 and DE-FG02-97ER54392.

Factors Affecting the Geo-effectiveness of Shocks and Sheaths at 1 AU.

PubMed

Lugaz, N; Farrugia, C J; Winslow, R M; Al-Haddad, N; Kilpua, E K J; Riley, P

2016-11-01

We identify all fast-mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes and geo-effects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geo-effective sheaths compress pre-existing southward B z . Most of the remaining sheaths appear to have planar structures with southward magnetic fields, including some with planar structures consistent with field line draping ahead of the magnetic ejecta. A typical (median) geo-effective shock-sheath structure drives a geomagnetic storm with peak Dst of -88 nT, pushes the subsolar magnetopause location to 6.3 R E , i.e. below geosynchronous orbit and is associated with substorms with a peak AL-index of -1350 nT. There are some important differences between sheaths associated with CME-CME interaction (stronger storms) and those associated with isolated CMEs (stronger compression of the magnetosphere). We detail six case studies of different types of geo-effective shock-sheaths, as well as two events for which there was no geomagnetic storm but other magnetospheric effects. Finally, we discuss our results in terms of space weather forecasting, and potential effects on Earth's radiation belts.

Factors Affecting the Geo-effectiveness of Shocks and Sheaths at 1 AU

PubMed Central

Lugaz, N.; Farrugia, C. J.; Winslow, R. M.; Al-Haddad, N.; Kilpua, E. K. J.; Riley, P.

2018-01-01

We identify all fast-mode forward shocks, whose sheath regions resulted in a moderate (56 cases) or intense (38 cases) geomagnetic storm during 18.5 years from January 1997 to June 2015. We study their main properties, interplanetary causes and geo-effects. We find that half (49/94) such shocks are associated with interacting coronal mass ejections (CMEs), as they are either shocks propagating into a preceding CME (35 cases) or a shock propagating into the sheath region of a preceding shock (14 cases). About half (22/45) of the shocks driven by isolated transients and which have geo-effective sheaths compress pre-existing southward Bz. Most of the remaining sheaths appear to have planar structures with southward magnetic fields, including some with planar structures consistent with field line draping ahead of the magnetic ejecta. A typical (median) geo-effective shock-sheath structure drives a geomagnetic storm with peak Dst of −88 nT, pushes the subsolar magnetopause location to 6.3 RE, i.e. below geosynchronous orbit and is associated with substorms with a peak AL-index of −1350 nT. There are some important differences between sheaths associated with CME-CME interaction (stronger storms) and those associated with isolated CMEs (stronger compression of the magnetosphere). We detail six case studies of different types of geo-effective shock-sheaths, as well as two events for which there was no geomagnetic storm but other magnetospheric effects. Finally, we discuss our results in terms of space weather forecasting, and potential effects on Earth’s radiation belts. PMID:29629250

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

DTIC Science & Technology

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

The fibrous flexor sheaths of the fingers.

PubMed Central

Jones, M M; Amis, A A

1988-01-01

The structure of the digital fibrous flexor sheath was examined by dissection and histology. The presence of a specific system of named fibrous tissue bands, forming annular and cruciate pulleys, was noted confirming details which are well established in the surgical literature although not detailed by the anatomical texts. These pulleys were linked by thin parts of the sheath. When the inner aspect of the sheath was examined, it was found that it was not a continuous smooth surface, as depicted in both anatomical and surgical texts. The thin parts of the sheath often overlapped the free edges of the pulleys before attaching to their superficial aspects, so that the pulleys possessed free edges within the sheath. Forty eight cadaveric fingers were examined in order to determine the frequency of occurrence and sizes of these overlaps. The largest and most frequent overlap was found at the distal end of the A2 pulley (which attaches to the proximal phalanx). Images Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 7 (cont.) Fig. 7 Fig. 8 Fig. 9 PMID:3417546

Protective sheath for a continuous measurement thermocouple

DOEpatents

Phillippi, R.M.

1991-12-03

Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device. 4 figures.

Ultrasound-Guided Rectus Sheath Block in Gynaecological Surgery with Pfannenstiel Incision

PubMed Central

Cüneyitoğlu, Şule; Türktan, Mediha; Biricik, Ebru; Özcengiz, Dilek

2015-01-01

Objective This study aimed to evaluate the effects of ultrasound-guided rectus sheath block in gynaecological surgery with Pfannenstiel incision. Methods After the approval of the ethics committee and the patients’ consent, 75 ASA I–II patients who were aged between 20 and 70 years and scheduled for a gynaecological surgery with Pfannenstiel incision were included in this study. After induction of general anaesthesia, patients were randomly divided into three groups. In Group UR patients (n=25), ultrasound-guided rectus sheath block with 0.25% levobupivacaine (0.2 mL kg−1) was performed. In Group SR patients (n=25), surgical rectus sheath block with 0.25% levobupivacaine (0.2 mL kg−1) was applied. In Group T (n=25) patients, tramadol (2 mg kg−1) was intravenously administered 30 min before the end of surgery. Patient-controlled analgesia device was established for postoperative pain relief in all groups. Haemodynamic data and inspired sevoflurane concentration were recorded during the operation. Pain scores, total tramadol consumption, supplemental analgesic requirement and side effects were postoperatively evaluated. Results Demographic characteristics, duration of surgery and haemodynamic parameters were similar between the groups. Inspired sevoflurane concentration (%) and VAS scores were significantly lower in Group UR than those in Groups SR and T. Total tramadol consumption was significantly lower in Groups UR and SR than that in Group T. There was no significant difference in the incidence of side effects. Conclusion This study demonstrates that ultrasound-guided rectus sheath block helps to provide the effective analgesia without any side effects compared with surgical rectus sheath block and intravenous tramadol for gynaecological surgery with Pfannenstiel incision. PMID:27366521

Ultrasound-Guided Rectus Sheath Block in Gynaecological Surgery with Pfannenstiel Incision.

PubMed

Cüneyitoğlu, Şule; Türktan, Mediha; Biricik, Ebru; Özcengiz, Dilek

2015-10-01

This study aimed to evaluate the effects of ultrasound-guided rectus sheath block in gynaecological surgery with Pfannenstiel incision. After the approval of the ethics committee and the patients' consent, 75 ASA I-II patients who were aged between 20 and 70 years and scheduled for a gynaecological surgery with Pfannenstiel incision were included in this study. After induction of general anaesthesia, patients were randomly divided into three groups. In Group UR patients (n=25), ultrasound-guided rectus sheath block with 0.25% levobupivacaine (0.2 mL kg(-1)) was performed. In Group SR patients (n=25), surgical rectus sheath block with 0.25% levobupivacaine (0.2 mL kg(-1)) was applied. In Group T (n=25) patients, tramadol (2 mg kg(-1)) was intravenously administered 30 min before the end of surgery. Patient-controlled analgesia device was established for postoperative pain relief in all groups. Haemodynamic data and inspired sevoflurane concentration were recorded during the operation. Pain scores, total tramadol consumption, supplemental analgesic requirement and side effects were postoperatively evaluated. Demographic characteristics, duration of surgery and haemodynamic parameters were similar between the groups. Inspired sevoflurane concentration (%) and VAS scores were significantly lower in Group UR than those in Groups SR and T. Total tramadol consumption was significantly lower in Groups UR and SR than that in Group T. There was no significant difference in the incidence of side effects. This study demonstrates that ultrasound-guided rectus sheath block helps to provide the effective analgesia without any side effects compared with surgical rectus sheath block and intravenous tramadol for gynaecological surgery with Pfannenstiel incision.

Conformal Fe3O4 sheath on aligned carbon nanotube scaffolds as high-performance anodes for lithium ion batteries.

PubMed

Wu, Yang; Wei, Yang; Wang, Jiaping; Jiang, Kaili; Fan, Shoushan

2013-02-13

A uniform Fe(3)O(4) sheath is magnetron sputtered onto aligned carbon nanotube (CNT) scaffolds that are directly drawn from CNT arrays. The Fe(3)O(4)-CNT composite electrode, with the size of Fe(3)O(4) confined to 5-7 nm, exhibits a high reversible capacity over 800 mAh g(-1) based on the total electrode mass, remarkable capacity retention, as well as high rate capability. The excellent performance is attributable to the superior electrical conductivity of CNTs, the uniform loading of Fe(3)O(4) sheath, and the structural retention of the composite anode on cycling. As Fe(3)O(4) is inexpensive and environmentally friendly, and the synthesis of Fe(3)O(4)-CNT is free of chemical wastes, this composite anode material holds considerable promise for high-performance lithium ion batteries.

Ultrasound guided injection inside the common sheath of the sciatic nerve at division level has a higher success rate than an injection outside the sheath.

PubMed

Lopez, A M; Sala-Blanch, X; Castillo, R; Hadzic, A

2014-01-01

The recommendations for the level of injection and ideal placement of the needle tip required for successful ultrasound-guided sciatic popliteal block vary among authors. A hypothesis was made that, when the local anesthetic is injected at the division of the sciatic nerve within the common connective tissue sheath, the block has a higher success rate than an injection outside the sheath. Thirty-four patients scheduled for hallux valgus repair surgery were randomized to receive either a sub-sheath block (n=16) or a peri-sheath block (n=18) at the level of the division of the sciatic nerve at the popliteal fossa. For the sub-sheath block, the needle was advanced out of plane until the tip was positioned between the tibial and peroneal nerves, and local anesthetic was then injected without moving the needle. For the peri-sheath block, the needle was advanced out of plane both sides of the sciatic nerve, to surround the sheath. Mepivacaine 1.5% and levobupivacaine 0.5% 30mL were used in both groups. The progression of motor and sensory block was assessed at 5min intervals. Duration of block was recorded. Adequate surgical block was achieved in all patients in the subsheath group (100%) compared to 12 patients (67%) in the peri-sheath group at 30min. Sensory block was achieved faster in the subsheath than peri-sheath (9.1±7.4min vs. 19.0±4.0; p<.001). Our study suggests that for successful sciatic popliteal block in less than 30min, local anesthetic should be injected within the sheath. Copyright © 2013 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Published by Elsevier España. All rights reserved.

Modeling of dynamic bipolar plasma sheaths

NASA Astrophysics Data System (ADS)

Grossmann, J. M.; Swanekamp, S. B.; Ottinger, P. F.

1991-08-01

The behavior of a one dimensional plasma sheath is described in regimes where the sheath is not in equilibrium because it carries current densities that are either time dependent, or larger than the bipolar Child-Langmuir level determined from the injected ion flux. Earlier models of dynamic bipolar sheaths assumed that ions and electrons evolve in a series of quasi-equilibria. In addition, sheath growth was described by the equation Zenoxs = (ji)-Zenouo, where xs is the velocity of the sheath edge, ji is the ion current density, nouo is the injected ion flux density, and Ze is the ion charge. In this paper, a generalization of the bipolar electron-to-ion current density ratio formula is derived to study regimes where ions are not in equilibrium. A generalization of the above sheath growth equation is also developed which is consistent with the ion continuity equation and which reveals new physics of sheath behavior associated with the emitted electrons and their evolution. Based on these findings, two new models of dynamic bipolar sheaths are developed. Larger sheath sizes and potentials than those of earlier models are found. In certain regimes, explosive sheath growth is predicted.

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

PubMed

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

2015-06-29

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.

Reactive oxygen species and redox regulation in mesophyll and bundle sheath cells of C4 plants.

PubMed

Turkan, Ismail; Uzilday, Baris; Dietz, Karl-Josef; Bräutigam, Andrea; Ozgur, Rengin

2018-02-26

Redox regulation, antioxidant defence and ROS signalling are critical in realizing and tuning metabolic activities. However, our concepts were mostly developed for C3 plants since Arabidopsis thaliana is major model. Efforts to convert C3 plants to C4 plants to increase yield (see C4 rice; c4rice.irri.org/) entails better understanding of these processes in C4 plants. Various photosynthetic enzymes that take part in light reactions and carbon reactions are regulated via redox components such as thioredoxins as redox transmitters and peroxiredoxins. Due to this, understanding redox regulation in mesophyll and bundle sheath chloroplasts of C4 plants is of paramount importance. It appears impossible to utilize efficient C4 photosynthesis without understanding its exact redox needs and regulation mechanisms used during light reactions. In this review we will discuss available knowledge on redox regulation in C3 and C4 plants with special emphasis on mesophyll and bundle sheath differences in C4. In these two cell types of C4 plants, linear and cyclic electron transport in chloroplasts operate differentially when compared to C3 chloroplasts, changing the redox needs of the cell. Therefore, the focus is given to photosynthetic light reactions, ROS production dynamics, antioxidant defence and thiol based redox regulation with the aim to draw a picture of current knowledge.

The H3-H4 N-Terminal Tail Domains Are the Primary Mediators of Transcription Factor IIIA Access to 5S DNA within a Nucleosome

PubMed Central

Vitolo, Joseph M.; Thiriet, Christophe; Hayes, Jeffrey J.

2000-01-01

Reconstitution of a DNA fragment containing a Xenopus borealis somatic type 5S rRNA gene into a nucleosome greatly restricts the binding of transcription factor IIIA (TFIIIA) to its cognate DNA sequence within the internal promoter of the gene. Removal of all core histone tail domains by limited trypsin proteolysis or acetylation of the core histone tails significantly relieves this inhibition and allows TFIIIA to exhibit high-affinity binding to nucleosomal DNA. Since only a single tail or a subset of tails may be primarily responsible for this effect, we determined whether removal of the individual tail domains of the H2A-H2B dimer or the H3-H4 tetramer affects TFIIIA binding to its cognate DNA site within the 5S nucleosome in vitro. The results show that the tail domains of H3 and H4, but not those of H2A and/or H2B, directly modulate the ability of TFIIIA to bind nucleosomal DNA. In vitro transcription assays carried out with nucleosomal templates lacking individual tail domains show that transcription efficiency parallels the binding of TFIIIA. In addition, we show that the stoichiometry of core histones within the 5S DNA-core histone-TFIIIA triple complex is not changed upon TFIIIA association. Thus, TFIIIA binding occurs by displacement of H2A-H2B–DNA contacts but without complete loss of the dimer from the nucleoprotein complex. These data, coupled with previous reports (M. Vettese-Dadey, P. A. Grant, T. R. Hebbes, C. Crane-Robinson, C. D. Allis, and J. L. Workman, EMBO J. 15:2508–2518, 1996; L. Howe, T. A. Ranalli, C. D. Allis, and J. Ausio, J. Biol. Chem. 273:20693–20696, 1998), suggest that the H3/H4 tails are the primary arbiters of transcription factor access to intranucleosomal DNA. PMID:10688663

Dentilisin activity affects the organization of the outer sheath of Treponema denticola.

PubMed

Ishihara, K; Kuramitsu, H K; Miura, T; Okuda, K

1998-08-01

Prolyl-phenylalanine-specific serine protease (dentilisin) is a major extracellular protease produced by Treponema denticola. The gene, prtP, coding for the protease was recently cloned and sequenced (K. Ishihara, T. Miura, H. K. Kuramitsu, and K. Okuda, Infect. Immun. 64:5178-5186, 1996). In order to determine the role of this protease in the physiology and virulence of T. denticola, a dentilisin-deficient mutant, K1, was constructed following electroporation with a prtP-inactivated DNA fragment. No chymotrypsin-like protease activity was detected in the dentilisin-deficient mutant. In addition, the high-molecular-mass oligomeric protein characteristic of the outer sheath of the organism decreased in the mutant. Furthermore, the hydrophobicity of the mutant was decreased, and coaggregation of the mutant with Fusobacterium nucleatum was enhanced compared to that of the wild-type organism. The results obtained with a mouse abscess model system indicated that the virulence of the mutant was attenuated relative to that of the wild-type organism. These results suggest that dentilisin activity plays a major role in the structural organization of the outer sheath of T. denticola. The loss of dentilsin activity and the structural change in the outer sheath affect the pathogenicity of T. denticola.

Ultrasound-guided fine needle aspiration in the diagnosis of peripheral nerve sheath tumors in 4 dogs

PubMed Central

da Costa, Ronaldo C.; Parent, Joane M.; Dobson, Howard; Ruotsalo, Kristiina; Holmberg, David; Duque, M. Carolina; Poma, Roberto

2008-01-01

Ultrasound-guided fine needle aspiration was used in establishing the diagnosis in 4 cases of malignant peripheral nerve sheath tumor. Sonographic and cytologic characteristics are discussed. Because of its availability and ease of use, axillary ultrasonography with fine needle aspiration can be an initial diagnostic step for suspected brachial plexus tumors. PMID:18320983

Diets of the Sympatric Pacific Sheath-Tailed Bat (Emballonura semicaudata rotensis) and Mariana Swiftlet (Aerodramus bartschi) on Aguiguan, Mariana Islands

USGS Publications Warehouse

Valdez, Ernest W.; Wiles, Gary J.; O'Shea, Thomas J.

2011-01-01

The Pacific sheath-tailed bat (Emballonura semicaudata rotensis) and Mariana swiftlet (Aerodramus bartschi) are two rare insectivorous taxa restricted to the southern Mariana Islands in western Micronesia. It is believed that populations of both have dwindled because of impacts to their food resources. However, there is little information on the food habits of A. bartschi and none exists for E. s. rotensis. In an effort to better understand the feeding habits of both, we investigated their diets using guano analysis. Guano was collected from two roosts in caves during a 2-week period in June and July at the onset of the rainy season. Important orders of insects consumed (percentage volume) by bats roosting at one cave included hymenopterans (64%), coleopterans (10%), lepidopterans (8%), isopterans (8%), and psocopterans (5%), whereas those at a second cave included lepidopterans (45%), hymenopterans (41%), coleopterans (10%), and isopterans (5%). Swiftlets, which roosted in only one of the caves, fed mostly on hymenopterans (88%) and hemipterans (6%). Significant differences existed between the two taxa in several insect orders eaten, with E. s. rotensis consuming more lepidopterans and coleopterans and A. bartschi taking more hymenopterans and hemipterans. Within Hymenoptera, bats fed more on ichneumoideans, whereas swiftlets ate more formicid alates and chalicidoideans. This new information on the feeding habits of E. s. rotensis and A. bartschi provides insight on the complexity of their diets during June and July, and serves as baseline information for future studies and management of their habitat.

Sinorhizobium meliloti Phage ΦM9 Defines a New Group of T4 Superfamily Phages with Unusual Genomic Features but a Common T=16 Capsid

PubMed Central

Johnson, Matthew C.; Tatum, Kelsey B.; Lynn, Jason S.; Brewer, Tess E.; Lu, Stephen; Washburn, Brian K.

2015-01-01

ABSTRACT Relatively little is known about the phages that infect agriculturally important nitrogen-fixing rhizobial bacteria. Here we report the genome and cryo-electron microscopy structure of the Sinorhizobium meliloti-infecting T4 superfamily phage ΦM9. This phage and its close relative Rhizobium phage vB_RleM_P10VF define a new group of T4 superfamily phages. These phages are distinctly different from the recently characterized cyanophage-like S. meliloti phages of the ΦM12 group. Structurally, ΦM9 has a T=16 capsid formed from repeating units of an extended gp23-like subunit that assemble through interactions between one subunit and the adjacent E-loop insertion domain. Though genetically very distant from the cyanophages, the ΦM9 capsid closely resembles that of the T4 superfamily cyanophage Syn9. ΦM9 also has the same T=16 capsid architecture as the very distant phage SPO1 and the herpesviruses. Despite their overall lack of similarity at the genomic and structural levels, ΦM9 and S. meliloti phage ΦM12 have a small number of open reading frames in common that appear to encode structural proteins involved in interaction with the host and which may have been acquired by horizontal transfer. These proteins are predicted to encode tail baseplate proteins, tail fibers, tail fiber assembly proteins, and glycanases that cleave host exopolysaccharide. IMPORTANCE Despite recent advances in the phylogenetic and structural characterization of bacteriophages, only a small number of phages of plant-symbiotic nitrogen-fixing soil bacteria have been studied at the molecular level. The effects of phage predation upon beneficial bacteria that promote plant growth remain poorly characterized. First steps in understanding these soil bacterium-phage dynamics are genetic, molecular, and structural characterizations of these groups of phages. The T4 superfamily phages are among the most complex phages; they have large genomes packaged within an icosahedral head and a long

C2 root nerve sheath tumors management.

PubMed

El-Sissy, Mohamed H; Mahmoud, Mostafa

2013-05-01

Upper cervical nerve sheath tumors (NST) arising mainly from C2 root and to lesser extent from C1 root are not uncommon, they constitute approximately 5-12% of spinal nerve sheath tumors and 18-30% of all cervical nerve sheath tumors, unique in presentation and their relationship to neighbouring structures owing to the discrete anatomy at the upper cervical-craniovertebral region, and have atendency for growth reaching large-sized tumors before manifesting clinically due to the capacious spinal canal at this region; accordingly the surgical approaches to such tumors are modified. The aim of this paper is to discuss the surgical strategies for upper cervical nerve sheath tumors. Eleven patients (8 male and 3 females), age range 28-63 years, with C2 root nerve sheath tumors were operated upon based on their anatomical relations to the spinal cord. The magnetic resonance imaging findings were utilized to determine the surgical approach. The tumors had extra- and intradural components in 10 patients, while in one the tumor was purely intradural. The operative approaches included varied from extreme lateral transcondylar approach(n = 1) to laminectomy, whether complete(n = 3) a or hemilaminectomy(n = 7), with partial facetectomy(n = 7), and with suboccipital craniectomy(n = 2). The clinical picture ranged from spasticity (n = 8, 72,72 %), tingling and numbness below neck (n = 6, 54,54 %), weakness (n = 6, 54,54 %), posterior column involvement (n = 4, 26,36 %), and neck pain (n = 4, 36,36 %). The duration of symptoms ranged from 1 to 54 months, total excision was performed in 7 patients; while in 3 patients an extraspinal component, and in 1 patient a small intradural component, were left in situ. Eight patients showed improvement of myelopathy; 2 patients maintained their grades. One poor-grade patient was deteriorated. The surgical approaches for the C2 root nerve sheath tumors should be tailored according to the relationship to the spinal cord, determined by magnetic

Ultrastructural differentiation of sperm tail region in Diplometopon zarudnyi (an amphisbaenian reptile)

PubMed Central

Al-Dokhi, O.; Mukhtar, Ahmed; Al-Dosary, A.; Al-Sadoon, M.K.

2015-01-01

Diplometopon zarudnyi, a worm lizard belongs to amphisbaenia under trogonophidae family. This species exists in limited areas of the Arabian Peninsula and is an oscillating digger found in sub-surface soils. The present study aimed to investigate the sperm tail differentiation in D. zarudnyi. Ten male adults of D. zarudnyi were collected from Riyadh during April–May 2011. To study the sperm tail at the ultrastructural level the testes were fixed in 3% glutaraldehyde, than post fixed in 1% osmium tetaroxide followed by dehydration in ethanol grades; samples were cleared in propylene oxide and embedded in resin. Tail formation begins by the moving of centrioles and mitochondria towards the posterior pole of sperm head. Simultaneously many microtubules of the midpiece axoneme were enclosed by a thick layer of granular material. Mitochondria of midpiece lie alongside the proximal centriole which forms a very short neck region and possess tubular cristae internally and concentric layers of cristae superficially. During this course a fibrous sheath surrounds the axoneme of mid and principal piece. At the end dissolution of longitudinal manchette takes place. The mitochondria then rearrange themselves around the proximal and distal centrioles to form a neck region. Later, the fibrous sheath surrounds the proximal portion of the flagella. This part along with sperm head of D. zarudnyi provides a classical model that could be used in future for evolutionary and phylogenetic purposes of class reptilia. PMID:26155090

RF sheaths for arbitrary B field angles

NASA Astrophysics Data System (ADS)

D'Ippolito, Daniel; Myra, James

2014-10-01

RF sheaths occur in tokamaks when ICRF waves encounter conducting boundaries and accelerate electrons out of the plasma. Sheath effects reduce the efficiency of ICRF heating, cause RF-specific impurity influxes from the edge plasma, and increase the plasma-facing component damage. The rf sheath potential is sensitive to the angle between the B field and the wall, the ion mobility and the ion magnetization. Here, we obtain a numerical solution of the non-neutral rf sheath and magnetic pre-sheath equations (for arbitrary values of these parameters) and attempt to infer the parametric dependences of the Child-Langmuir law. This extends previous work on the magnetized, immobile ion regime. An important question is how the rf sheath voltage distributes itself between sheath and pre-sheath for various B field angles. This will show how generally previous estimates of the rf sheath voltage and capacitance were reasonable, and to improve the RF sheath BC. Work supported by US DOE grants DE-FC02-05ER54823 and DE-FG02-97ER54392.

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

PubMed Central

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. PMID:26160988

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

NASA Astrophysics Data System (ADS)

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

2008-10-01

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.

THE NARROW X-RAY TAIL AND DOUBLE Hα TAILS OF ESO 137-002 IN A3627

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

Zhang, B.; Lin, X. B.; Kong, X.

2013-11-10

We present the analysis of a deep Chandra observation of a ∼2 L{sub *} late-type galaxy, ESO 137-002, in the closest rich cluster A3627. The Chandra data reveal a long (∼>40 kpc) and narrow tail with a nearly constant width (∼3 kpc) to the southeast of the galaxy, and a leading edge ∼1.5 kpc from the galaxy center on the upstream side of the tail. The tail is most likely caused by the nearly edge-on stripping of ESO 137-002's interstellar medium (ISM) by ram pressure, compared to the nearly face-on stripping of ESO 137-001 discussed in our previous work. Spectralmore » analysis of individual regions along the tail shows that the gas throughout it has a rather constant temperature, ∼1 keV, very close to the temperature of the tails of ESO 137-001, if the same atomic database is used. The derived gas abundance is low (∼0.2 solar with the single-kT model), an indication of the multiphase nature of the gas in the tail. The mass of the X-ray tail is only a small fraction (<5%) of the initial ISM mass of the galaxy, suggesting that the stripping is most likely at an early stage. However, with any of the single-kT, double-kT, and multi-kT models we tried, the tail is always 'over-pressured' relative to the surrounding intracluster medium (ICM), which could be due to the uncertainties in the abundance, thermal versus non-thermal X-ray emission, or magnetic support in the ICM. The Hα data from the Southern Observatory for Astrophysical Research show a ∼21 kpc tail spatially coincident with the X-ray tail, as well as a secondary tail (∼12 kpc long) to the east of the main tail diverging at an angle of ∼23° and starting at a distance of ∼7.5 kpc from the nucleus. At the position of the secondary Hα tail, the X-ray emission is also enhanced at the ∼2σ level. We compare the tails of ESO 137-001 and ESO 137-002, and also compare the tails to simulations. Both the similarities and differences of the tails pose challenges to the simulations. Several

Diets of the sympatric pacific sheath-tailed bat (Emballonura semicaudata rotensis) and Mariana Swiftlet (Aerodramus bartscht) on Aguiguan, Mariana Islands

USGS Publications Warehouse

Valdez, E.W.; Wiles, G.J.; O'Shea, T.J.

2011-01-01

The Pacific sheath-tailed bat (Emballonura semicaudata rotensis) and Mariana swiftlet (Aerodramus bartschi) are two rare insectivorous taxa restricted to the southern Mariana Islands in western Micronesia. It is believed that populations of both have dwindled because of impacts to their food resources. However, there is little information on the food habits of A. bartschi and none exists for E. s. rotensis. In an effort to better understand the feeding habits of both, we investigated their diets using guano analysis. Guano was collected from two roosts in caves during a 2-week period in June and July at the onset of the rainy season. Important orders of insects consumed (percentage volume) by bats roosting at one cave included hymenopterans (64%), coleopterans (10%), lepidopterans (8%), isopterans (8%), and psocopterans (5%), whereas those at a second cave included lepidopterans (45%), hymenopterans (41%), coleopterans (10%), and isopterans (5%). Swiftlets, which roosted in only one of the caves, fed mostly on hymenopterans (88%) and hemipterans (6%). Significant differences existed between the two taxa in several insect orders eaten, with E. s. rotensis consuming more lepidopterans and coleopterans and A. bartschi taking more hymenopterans and hemipterans. Within Hymenoptera, bats fed more on ichneumoideans, whereas swiftlets ate more formicid alates and chalicidoideans. This new information on the feeding habits of E. s. rotensis and A. bartschi provides insight on the complexity of their diets during June and July, and serves as baseline information for future studies and management of their habitat. ?? 2011 by University of Hawai'i Press All rights reserved.

Effect of secondary electron emission on the plasma sheath

NASA Astrophysics Data System (ADS)

Langendorf, S.; Walker, M.

2015-03-01

In this experiment, plasma sheath potential profiles are measured over boron nitride walls in argon plasma and the effect of secondary electron emission is observed. Results are compared to a kinetic model. Plasmas are generated with a number density of 3 × 1012 m-3 at a pressure of 10-4 Torr-Ar, with a 1%-16% fraction of energetic primary electrons. The sheath potential profile at the surface of each sample is measured with emissive probes. The electron number densities and temperatures are measured in the bulk plasma with a planar Langmuir probe. The plasma is non-Maxwellian, with isotropic and directed energetic electron populations from 50 to 200 eV and hot and cold Maxwellian populations from 3.6 to 6.4 eV and 0.3 to 1.3 eV, respectively. Plasma Debye lengths range from 4 to 7 mm and the ion-neutral mean free path is 0.8 m. Sheath thicknesses range from 20 to 50 mm, with the smaller thickness occurring near the critical secondary electron emission yield of the wall material. Measured floating potentials are within 16% of model predictions. Measured sheath potential profiles agree with model predictions within 5 V (˜1 Te), and in four out of six cases deviate less than the measurement uncertainty of 1 V.

Sperm with fibrous sheath dysplasia and anomalies in head-neck junction: focus on centriole and centrin 1.

PubMed

Moretti, E; Pascarelli, N A; Belmonte, G; Renieri, T; Collodel, G

2017-09-01

Spermatozoa with a rare combination of two monomorphic sperm defects, dysplasia of the fibrous sheath (DFS) and alterations in head-mid-piece junction were analysed. The main focus was to explore the status of the centriole, a key organisation during fertilisation, using the centrin 1, a calcium-binding protein linked to this structure. The sperm quality was examined by light, scanning and transmission electron microscopy (SEM, TEM); immunocytochemistry was performed for tubulin, A-kinase anchor protein 4 (AKAP4) and centrin 1. Spermatozoa showed DFS defect associated with anomalies in head-tail attachment detected by SEM and TEM. Immunolocalisation of tubulin, AKAP4 and centrin 1 confirmed these alterations. Centrin 1 was visible in 67% of spermatozoa (in only 13% centrin localised in a normal position); in the majority of sperm centrin 1's location was altered, sometimes bent; often four spots, indicating the presence of two implantation fossae, were detected. At the centriolar level, immunoreactive fragments, frequently invading the entire short and thick tail, were observed. Centrin 1 is an essential component of the spermatozoa connecting piece and plays a role in centrosome dynamics during sperm morphogenesis and in zygotes and early embryos during spindle assembly. It is important to shed light on these rare conditions in order to better manage the patients during assisted reproductive technology. © 2016 Blackwell Verlag GmbH.

The Distant Tail Behavior During High Speed Solar Wind Streams and Magnetic Storms

NASA Technical Reports Server (NTRS)

Ho, C. M.; Tsurutani, B. T.

1996-01-01

We have examined the ISEE-3 distant tail data during three intense (Dst< -100(sub n)T) magnetic storms and have identified the tail response to high speed solar wind streams, interplanetary magnetic clouds, and near-Earth storms. The three storms have a peak Dst ranging from -150 to -220 nT, and occur on Jan. 9, Feb. 4, and Aug. 8, 1993.

Tail proteins of phage T5: investigation of the effect of the His6-tag position, from expression to crystallisation.

PubMed

Noirclerc-Savoye, Marjolaine; Flayhan, Ali; Pereira, Cindy; Gallet, Benoit; Gans, Pierre; Ebel, Christine; Breyton, Cécile

2015-05-01

Upon binding to its bacterial host receptor, the tail tip of phage T5 perforates, by an unknown mechanism, the heavily armoured cell wall of the host. This allows the injection of phage DNA into the cytoplasm to hijack the cell machinery and enable the production of new virions. In the perspective of a structural study of the phage tail, we have systematically overproduced eight of the eleven T5 tail proteins, with or without a N- or a C-terminal His6-tag. The widely used Hi6-tag is very convenient to purify recombinant proteins using immobilised-metal affinity chromatography. The presence of a tag however is not always innocuous. We combined automated gene cloning and expression tests to rapidly identify the most promising constructs for proteins of phage T5 tail, and performed biochemical and biophysical characterisation and crystallisation screening on available proteins. Automated small-scale purification was adapted for two highly expressed proteins. We obtained structural information for three of the proteins. We showed that the presence of a His6-tag can have drastic effect on protein expression, solubility, oligomerisation propensity and crystal quality. Copyright © 2015 Elsevier Inc. All rights reserved.

Gold ink coating of thermocouple sheaths

DOEpatents

Ruhl, H. Kenneth

1992-01-01

A method is provided for applying a gold ink coating to a thermocouple sheath which includes the steps of electropolishing and oxidizing the surface of the thermocouple sheath, then dipping the sheath into liquid gold ink, and finally heat curing the coating. The gold coating applied in this manner is highly reflective and does not degrade when used for an extended period of time in an environment having a temperature over 1000.degree. F. Depending on the application, a portion of the gold coating covering the tip of the thermocouple sheath is removed by abrasion.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

NASA Astrophysics Data System (ADS)

Takahashi, Takuya; Shibata, Kazunari

2017-03-01

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.

Sheath-accumulating Propagation of Interplanetary Coronal Mass Ejection

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

Takahashi, Takuya; Shibata, Kazunari, E-mail: takahasi@kusastro.kyoto-u.ac.jp

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”more » (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.« less

Plasma-Sheath-Surface Dynamics

DTIC Science & Technology

1990-09-01

Particle Simulations of Cross-Field Plasma Sheaths," Phys. Fluids B, pp 1069- 1082 , May 1990. IJ. Morey and C.K. Birdsall, "Traveling Wave-Tube Simulation...Theilhaber, "Analytic Solutions and Particle Simulations of Cross-Field Plasma Sheaths," Phys. Fluids B, pp 1069- 1082 , May 1990. S.E. Parker, and C.K

Acceptance by black-tailed deer of foliage treated with herbicides.

Treesearch

Dan L. Campbell; James Evans; Gerald D. Lindsey; William E. Dusenberry

1981-01-01

To test their acceptance of foliage treated with herbicides, captive black-tailed deer were exposed to Douglas-fir seedlings and salal treated with standard formulations of 2,4,5-T, 2,4-D, atrazine, dalapon, fosamine, and glyphosate herbicides. Carriers were diesel oil and water. Tests were made from November 1977 through February 1978. Deer readily browsed 2,4,5-T...

Radio frequency sheaths in an oblique magnetic field

DOE PAGES

Myra, James R.; D'Ippolito, Daniel A.

2015-06-01

The physics of radio-frequency (rf) sheaths near a conducting surface is studied for plasmas immersed in a magnetic field that makes an oblique angle θ with the surface. A set of one-dimensional equations is developed that describe the dynamics of the time-dependent magnetic presheath and non-neutral Debye sheath. The model employs Maxwell-Boltzmann electrons, and the magnetization and mobility of the ions is determined by the magnetic field strength, and wave frequency, respectively. The angle, θ assumed to be large enough to insure an electron-poor sheath, is otherwise arbitrary. Concentrating on the ion-cyclotron range of frequencies, the equations are solved numericallymore » to obtain the rectified (dc) voltage, the rf voltage across the sheath and the rf current flowing through the sheath. As an application of this model, the sheath voltage-current relation is used to obtain the rf sheath impedance, which in turn gives an rf sheath boundary condition for the electric field at the sheath-plasma interface that can be used in rf wave codes. In general the impedance has both resistive and capacitive contributions, and generalizes previous sheath boundary condition models. The resistive part contributes to parasitic power dissipation at the wall.« less

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application

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

Ma, Dongyang; Wang, Zhendong; Guo, Min

2014-11-15

Highlights: • Concept to convert waste to valuable product is carried out in this study. • An industrially feasible and cost-effective approach was developed and optimized. • Highly crystalline and well-defined zeolite was produced under moderate conditions. • The zeolite derived from the bauxite tailings displayed high ion exchange capacity. • Bauxite tailings have potential application in heavy metal ions adsorbent. - Abstract: Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceivedmore » and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO{sub 3}/g, comparable to commercially-available zeolite (310 mg CaCO{sub 3}/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China.« less

Ion sheath dynamics in a plasma for plasma-based ion implantation

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

Yatsuzuka, M.; Miki, S.; Azuma, K.

1999-07-01

Spatial and temporal growth and collapse of ion sheath around an electrode of a negative high-voltage pulse (voltage: {minus}10 kV, pulse duration: 10 {micro}s) have been studied in a plasma for plasma-based ion implantation. A spherical electrode of 1.9 cm in a diameter is immersed in a nitrogen plasma with the plasma density range of 10{sup 9} to 10{sup 10} cm{sup {minus}3}, the electron temperature of 1.4 eV and the gas pressure of 8x10{sup {minus}4} Torr. The transient sheath dynamics was observed by the measurement of electron saturation current to a Langmuir probe, where a depletion of electron saturation currentmore » indicates the arrival time of sheath edge at the probe position. The expanding speed of sheath edge is higher than the ion acoustic speed until the sheath length reaches the steady-state extent determined by Child-Langmuir law. In the region beyond the steady-state extent, the rarefying disturbance produced by sheath expansion continues to propagate into the plasma at the ion acoustic peed. After the pulse voltage is returned to zero (more exactly, the floating potential), the electron current begins to recover. When the pulse fall time is shorter than the plasma transit time, the electron saturation current overshoots the steady-state saturation current at once, resulting in an excess of plasma density which propagates like a tidal wave into the plasma at the ion acoustic speed.« less

Feasible conversion of solid waste bauxite tailings into highly crystalline 4A zeolite with valuable application.

PubMed

Ma, Dongyang; Wang, Zhendong; Guo, Min; Zhang, Mei; Liu, Jingbo

2014-11-01

Bauxite tailings are a major type of solid wastes generated in the flotation process. The waste by-products caused significant environmental impact. To lessen this hazardous effect from poisonous mine tailings, a feasible and cost-effective solution was conceived and implemented. Our approach focused on reutilization of the bauxite tailings by converting it to 4A zeolite for reuse in diverse applications. Three steps were involved in the bauxite conversion: wet-chemistry, alkali fusion, and crystallization to remove impurities and to prepare porous 4A zeolite. It was found that the cubic 4A zeolite was single phase, in high purity, with high crystallinity and well-defined structure. Importantly, the 4A zeolite displayed maximum calcium ion exchange capacity averaged at 296 mg CaCO3/g, comparable to commercially-available zeolite (310 mg CaCO3/g) exchange capacity. Base on the optimal synthesis condition, the reaction yield of zeolite 4A from bauxite tailings achieved to about 38.43%, hence, this study will provide a new paradigm for remediation of bauxite tailings, further mitigating the environmental and health care concerns, particularly in the mainland of PR China. Copyright © 2014 Elsevier Ltd. All rights reserved.

Control of Bacteriophage T4 Tail Lysozyme Activity During the Infection Process

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

Kanamaru, Shuji; Ishiwata, Yasutaka; Suzuki, Toshiharu

2010-07-19

Bacteriophage T4 has an efficient mechanism for injecting the host Escherichia coli cell with genomic DNA. Its gene product 5 (gp5) has a needle-like structure attached to the end of a tube through which the DNA passes on its way out of the head and into the host. The gp5 needle punctures the outer cell membrane and then digests the peptidoglycan cell wall in the periplasmic space. gp5 is normally post-translationally cleaved between residues 351 and 352. The function of this process in controlling the lysozyme activity of gp5 has now been investigated. When gp5 is over-expressed in E. coli,more » two mutants (S351H and S351A) showed a reduction of cleavage products and five other mutants (S351L, S351K, S351Y, S351Q, and S351T) showed no cleavage. Furthermore, in a complementation assay at 20 C, the mutants that had no cleavage of gp5 produced a reduced number of plaques compared to wild-type T4. The crystal structure of the non-cleavage phenotype mutant of gp5, S351L, complexed with gene product 27, showed that the 18 residues in the vicinity of the potential cleavage site (disordered in the wild-type structure) had visible electron density. The polypeptide around the potential cleavage site is exposed, thus allowing access for an E. coli protease. The lysozyme activity is inhibited in the wild-type structure by a loop from the adjacent gp5 monomer that binds into the substrate-binding site. The same inhibition is apparent in the mutant structure, showing that the lysozyme is inhibited before gp5 is cleaved and, presumably, the lysozyme is activated only after gp5 has penetrated the outer membrane.« less

Particle-in-cell study of the ion-to-electron sheath transition

DOE PAGES

Scheiner, Brett; Baalrud, Scott D.; Hopkins, Matthew M.; ...

2016-08-09

The form of a sheath near a small electrode, with bias changing from below to above the plasma potential, is studied using 2D particle-in-cell simulations. When the electrode is biased within T e/2 e below the plasma potential, the electron velocity distribution functions (EVDFs) exhibit a loss-cone type truncation due to fast electrons overcoming the small potential difference between the electrode and plasma. No sheath is present in this regime, and the plasma remains quasineutral up to the electrode. The EVDF truncation leads to a presheath-like density and flow velocity gradients. Once the bias exceeds the plasma potential, an electronmore » sheath is present. In this case, the truncation driven behavior persists, but is accompanied by a shift in the maximum value of the EVDF that is not present in the negative bias cases. In conclusion, the flow moment has significant contributions from both the flow shift of the EVDF maximum, and the loss-cone truncation.« less

Rectus sheath catheters for continuous analgesia after upper abdominal surgery.

PubMed

Cornish, Philip; Deacon, Alf

2007-01-01

The segmental nerves T6-T11 pass through and innervate the rectus abdominis muscle and overlying skin. The arcuate lines compartmentalize the rectus, but they are deficient posteriorly and hence a catheter tunnelled into the posterior sheath can be used to achieve an effective continuous analgesic block. Volume is important to fill the compartment. It is a simple surgical procedure that has several advantages and appears a viable alternative to epidural analgesia.

Transient sheath overvoltages in armored power cables

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

Gustavsen, B.; Sletbak, J.

1996-07-01

This paper is concerned with methods of limiting the build-up of transient voltages between sheath and armor in long armored power cables. Calculations by a frequency dependent cable model demonstrate that this voltage can be efficiently limited to an acceptable level by introducing sheath-armor bondings at regular intervals, or by using a semiconductive sheath-armor interlayer. The paper investigates the required minimum length between bondings, as well as the required conductivity of the sheath-armor interlayer if the use of bondings is to be avoided.

Theoretical and computational studies of the sheath of a planar wall

NASA Astrophysics Data System (ADS)

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).

Laminated magnet field coil sheath

DOEpatents

Skaritka, J.R.

1987-05-15

A method for manufacturing a magnetic cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible substrate sheath, with the trim coil pattern precisely location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator. 1 fig.

A Cytochemical Study of Extracellular Sheaths Associated with Rigidoporus lignosus during Wood Decay

PubMed Central

Nicole, M.; Chamberland, H.; Rioux, D.; Lecours, N.; Rio, B.; Geiger, J. P.; Ouellette, G. B.

1993-01-01

An ultrastructural and cytochemical investigation of the development of Rigidoporus lignosus, a white-rot fungus inoculated into wood blocks, was carried out to gain better insight into the structure and role of the extracellular sheaths produced by this fungus during wood degradation. Fungal sheaths had a dense or loose fibrillar appearance and were differentiated from the fungal cell wall early after wood inoculation. Close association between extracellular fibrils and wood cell walls was observed at both early and advanced stages of wood alteration. Fungal sheaths were often seen deep in host cell walls, sometimes enclosing residual wood fragments. Specific gold probes were used to investigate the chemical nature of R. lignosus sheaths. While labeling of chitin, pectin, β-1,4- and β-1,3-glucans, β-glucosides, galactosamine, mannose, sialic acid, RNA, fucose, and fimbrial proteins over fungal sheaths did not succeed, galactose residues and laccase (a fungal phenoloxidase) were found to be present. The positive reaction of sheaths with the PATAg test indicates that polysaccharides such as β-1,6-glucans are important components. Our data suggest that extracellular sheaths produced by R. lignosus during host cell colonization play an important role in wood degradation. Transportation of lignin-degrading enzymes by extracellular fibrils indicates that alteration of plant polymers may occur within fungal sheaths. It is also proposed that R. lignosus sheaths may be involved in recognition mechanisms in fungal cell-wood surface interactions. Images PMID:16349017

Nerve sheath myxoma: report of a rare case.

PubMed

Bhat, Amoolya; Narasimha, Apaparna; C, Vijaya; Vk, Sundeep

2015-04-01

Nerve sheath myxoma defined by Harkin and Reed is an uncommon benign neoplasm with nerve sheath like features. It has several cytological and histological differential diagnoses. One such lesion is neurothekeoma, which can be differentiated using immunohistochemistry. In most of the previous reports nerve sheath myxoma and neurothekeoma were considered synonymous and were often confused for one another. This case report separates the two using immunohistochemistry. Also, the cytological features of nerve sheath myxoma are not well documented in the past. This case report attempts to display the cyto-morphology of nerve sheath myxoma. We report a rare case of nerve sheath myxoma diagnosed on cytological features confirmed by histopathology and immunohistochemistry in a 32-year-old lady who presented with an asymptomatic nodule over the left cervical area and discuss its cyto-histological mimics.

Co-electrospinning fabrication and photocatalytic performance of TiO{sub 2}/SiO{sub 2} core/sheath nanofibers with tunable sheath thickness

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

Cao, Houbao, E-mail: caohoubao66@163.com; Du, Pingfan; Song, Lixin

2013-11-15

Graphical abstract: - Highlights: • The core–sheath TiO{sub 2}/SiO{sub 2} nanofibers were fabricated by co-electrospinning technique. • The catalytic property of nanofibers with different sheath thickness was studied. • The potential methods of improving catalytic efficiency are suggested. - Abstract: In this paper, core/sheath TiO{sub 2}/SiO{sub 2} nanofibers with tunable sheath thickness were directly fabricated via a facile co-electrospinning technique with subsequent calcination at 500 °C. The morphologies and structures of core/sheath TiO{sub 2}/SiO{sub 2} nanofibers were characterized by TGA, FESEM, TEM, FTIR, XPS and BET. It was found that the 1D core/sheath nanofibers are made up of anatase–rutile TiO{submore » 2} core and amorphous SiO{sub 2} sheath. The influences of SiO{sub 2} sheath and its thickness on the photoreactivity were evaluated by observing photo-degradation of methylene blue aqueous solution under the irradiation of UV light. Compared with pure TiO{sub 2} nanofibers, the core/sheath TiO{sub 2}/SiO{sub 2} nanofibers performed a better catalytic performance. That was attributed to not only efficient separation of hole–electron pairs resulting from the formation of heterojunction but also larger surface area and surface silanol group which will be useful to provide higher capacity for oxygen adsorption to generate more hydroxyl radicals. And the optimized core/sheath TiO{sub 2}/SiO{sub 2} nanofibers with a sheath thickness of 37 nm exhibited the best photocatalytic performance.« less

Analytical model for the radio-frequency sheath

NASA Astrophysics Data System (ADS)

Czarnetzki, Uwe

2013-12-01

A simple analytical model for the planar radio-frequency (rf) sheath in capacitive discharges is developed that is based on the assumptions of a step profile for the electron front, charge exchange collisions with constant cross sections, negligible ionization within the sheath, and negligible ion dynamics. The continuity, momentum conservation, and Poisson equations are combined in a single integro-differential equation for the square of the ion drift velocity, the so called sheath equation. Starting from the kinetic Boltzmann equation, special attention is paid to the derivation and the validity of the approximate fluid equation for momentum balance. The integrals in the sheath equation appear in the screening function which considers the relative contribution of the temporal mean of the electron density to the space charge in the sheath. It is shown that the screening function is quite insensitive to variations of the effective sheath parameters. The two parameters defining the solution are the ratios of the maximum sheath extension to the ion mean free path and the Debye length, respectively. A simple general analytic expression for the screening function is introduced. By means of this expression approximate analytical solutions are obtained for the collisionless as well as the highly collisional case that compare well with the exact numerical solution. A simple transition formula allows application to all degrees of collisionality. In addition, the solutions are used to calculate all static and dynamic quantities of the sheath, e.g., the ion density, fields, and currents. Further, the rf Child-Langmuir laws for the collisionless as well as the collisional case are derived. An essential part of the model is the a priori knowledge of the wave form of the sheath voltage. This wave form is derived on the basis of a cubic charge-voltage relation for individual sheaths, considering both sheaths and the self-consistent self-bias in a discharge with arbitrary

Analytical model for the radio-frequency sheath.

PubMed

Czarnetzki, Uwe

2013-12-01

A simple analytical model for the planar radio-frequency (rf) sheath in capacitive discharges is developed that is based on the assumptions of a step profile for the electron front, charge exchange collisions with constant cross sections, negligible ionization within the sheath, and negligible ion dynamics. The continuity, momentum conservation, and Poisson equations are combined in a single integro-differential equation for the square of the ion drift velocity, the so called sheath equation. Starting from the kinetic Boltzmann equation, special attention is paid to the derivation and the validity of the approximate fluid equation for momentum balance. The integrals in the sheath equation appear in the screening function which considers the relative contribution of the temporal mean of the electron density to the space charge in the sheath. It is shown that the screening function is quite insensitive to variations of the effective sheath parameters. The two parameters defining the solution are the ratios of the maximum sheath extension to the ion mean free path and the Debye length, respectively. A simple general analytic expression for the screening function is introduced. By means of this expression approximate analytical solutions are obtained for the collisionless as well as the highly collisional case that compare well with the exact numerical solution. A simple transition formula allows application to all degrees of collisionality. In addition, the solutions are used to calculate all static and dynamic quantities of the sheath, e.g., the ion density, fields, and currents. Further, the rf Child-Langmuir laws for the collisionless as well as the collisional case are derived. An essential part of the model is the a priori knowledge of the wave form of the sheath voltage. This wave form is derived on the basis of a cubic charge-voltage relation for individual sheaths, considering both sheaths and the self-consistent self-bias in a discharge with arbitrary

Molecular dynamics simulations demonstrate the regulation of DNA-DNA attraction by H4 histone tail acetylations and mutations.

PubMed

Korolev, Nikolay; Yu, Hang; Lyubartsev, Alexander P; Nordenskiöld, Lars

2014-10-01

The positively charged N-terminal histone tails play a crucial role in chromatin compaction and are important modulators of DNA transcription, recombination, and repair. The detailed mechanism of the interaction of histone tails with DNA remains elusive. To model the unspecific interaction of histone tails with DNA, all-atom molecular dynamics (MD) simulations were carried out for systems of four DNA 22-mers in the presence of 20 or 16 short fragments of the H4 histone tail (variations of the 16-23 a. a. KRHRKVLR sequence, as well as the unmodified fragment a. a.13-20, GGAKRHRK). This setup with high DNA concentration, explicit presence of DNA-DNA contacts, presence of unstructured cationic peptides (histone tails) and K(+) mimics the conditions of eukaryotic chromatin. A detailed account of the DNA interactions with the histone tail fragments, K(+) and water is presented. Furthermore, DNA structure and dynamics and its interplay with the histone tail fragments binding are analysed. The charged side chains of the lysines and arginines play major roles in the tail-mediated DNA-DNA attraction by forming bridges and by coordinating to the phosphate groups and to the electronegative sites in the minor groove. Binding of all species to DNA is dynamic. The structure of the unmodified fully-charged H4 16-23 a.a. fragment KRHRKVLR is dominated by a stretched conformation. The H4 tail a. a. fragment GGAKRHRK as well as the H4 Lys16 acetylated fragment are highly flexible. The present work allows capturing typical features of the histone tail-counterion-DNA structure, interaction and dynamics. © 2014 Wiley Periodicals, Inc.

Nerve Sheath Myxoma: Report of A Rare Case

PubMed Central

Bhat, Amoolya; C, Vijaya; VK, Sundeep

2015-01-01

Nerve sheath myxoma defined by Harkin and Reed is an uncommon benign neoplasm with nerve sheath like features. It has several cytological and histological differential diagnoses. One such lesion is neurothekeoma, which can be differentiated using immunohistochemistry. In most of the previous reports nerve sheath myxoma and neurothekeoma were considered synonymous and were often confused for one another. This case report separates the two using immunohistochemistry. Also, the cytological features of nerve sheath myxoma are not well documented in the past. This case report attempts to display the cyto-morphology of nerve sheath myxoma. We report a rare case of nerve sheath myxoma diagnosed on cytological features confirmed by histopathology and immunohistochemistry in a 32-year-old lady who presented with an asymptomatic nodule over the left cervical area and discuss its cyto-histological mimics. PMID:26023558

Measurement of plasma sheath overlap above a trench

NASA Astrophysics Data System (ADS)

Sheridan, T. E.; Steinberger, Thomas E.

2017-06-01

The plasma sheath above a rectangular trench has been experimentally characterized as the trench width is varied in a radio frequency (rf) plasma discharge for two different rf powers giving two different sets of plasma parameters. Measurements were made using the positions and all six normal mode frequencies of two dust particles floating just inside the sheath edge above the center of the trench. We find that sheath overlap occurs when the trench width ≲ 3 s 0 for a trench depth ≈0.7s0, where s0 is the planar sheath width. The electric field gradient inside the sheath edge increases with rf power.

Comprehensive Study of Plasma-Wall Sheath Transport Phenomena

DTIC Science & Technology

2012-09-10

environment, a Langmuir probe and a Retarding Potential Analyzer (RPA). The Langmuir probe could be considered the seminal plasma diagnostic, and a large...plasma-sheath interface. Electric field is normalized by Te/LD (LD is the Debye length) and velocity is normalized by the Bohm speed. Figure 14...studying the interaction of the near-wall plasma sheath with a magnetic field , and modeled the plasma sheath of the GT thick-sheath (~10mm) plasma

Magnetic nanofibers with core (Fe 3O 4 nanoparticle suspension)/sheath (poly ethylene terephthalate) structure fabricated by coaxial electrospinning

NASA Astrophysics Data System (ADS)

Sung, Yun Kyung; Ahn, Byung Wook; Kang, Tae Jin

2012-03-01

One-dimensional magnetic nanostructures have recently attracted much attention because of their intriguing properties that are not realized by their bulk or particle form. These nanostructures are potentially useful for the application to ultrahigh-density data storages, sensors and bulletproof vest. The magnetic particles in magnetic nanofibers of blend types cannot fully align along the external magnetic field because magnetic particles are arrested in solid polymer matrix. To improve the mobility of magnetic particles, we used magneto-rheological fluid (MRF), which has the good mobility and dispersibility. Superparamagnetic core/sheath composite nanofibers were obtained with MRF and poly (ethylene terephthalate) (PET) solution via a coaxial electrospinning technique. Coaxial electrospinning is suited for fabricating core/sheath nanofibers encapsulating MRF materials within a polymer sheath. The magnetic nanoparticles in MRF were dispersed within core part of the nanofibers. The core/sheath magnetic composite nanofibers exhibited superparamagnetic behavior at room temperature and the magnetic nanoparticles in MRF well responded to an applied magnetic field. Also, the mechanical properties of the nanofiber were improved in the magnetic field. This study aimed to fabricate core/sheath magnetic composite nanofibers using coaxial electrospinning and characterize the magnetic as well as mechanical properties of composite nanofibers.

Laminated magnet field coil sheath

DOEpatents

Skaritka, John R.

1987-12-01

a method for manufacturing a magnet cable trim coil in a sheath assembly for use in a cryogenic particle accelerator. A precisely positioned pattern of trim coil turns is bonded to a flexible substrate sheath that is capable of withstanding cryogenic operating conditions. In the method of the invention the flexible sheath, with the trim coil pattern precisely positioned thereon, is accurately positioned at a precise location relative to a bore tube assembly of an accelerator and is then bonded to the bore tube with a tape suitable for cryogenic application. The resultant assembly can be readily handled and installed within an iron magnet yoke assembly of a suitable cryogenic particle accelerator.

Proteomic Analysis Reveals the Contribution of TGFβ/Smad4 Signaling Pathway to Cell Differentiation During Planarian Tail Regeneration.

PubMed

Chen, Xiaoguang; Xu, Cunshuan

2017-06-01

After planarian tail is cut off, posterior end of the remaining fragment will regenerate a new tail within about 1 week. However, many details of this process remain unclear up to date. For this reason, we performed the dynamic proteomic analysis of the regenerating tail fragments at 6, 12, 24, 72, 120, and 168 h post-amputation (hpa). Using two-dimensional electrophoresis (2-DE) in combination with MALDI-TOF-TOF/MS analysis, a total of 1088 peptides were identified as significantly changed between tail-cutting groups and 0-h group, 482 of which have identifiable protein names. Of these 482 proteins, there were 111 originating from the Turbellaria. Protein functional categorization showed that these 111 proteins are mainly related to differentiation and development, transcription and translation, cell signal transduction, and cell proliferation. The screening of key protein considered the transcription factor Smad4 as important protein for planarian tail regeneration. Cell signaling pathway analysis, combined with proteomic profiling of regenerating tail fragment, showed that TGFβ/Smad4 pathway was activated during planarian tail regeneration. Based on a comprehensive analysis of 2-DE MALDI-TOF-TOF/MS and bioinformatics analyses, it could be concluded that TGFβ/Smad4 pathway perhaps plays an important role in tail regeneration via promoting cell differentiation.

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

NASA Astrophysics Data System (ADS)

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.

Theory of ion-matrix-sheath dynamics

NASA Astrophysics Data System (ADS)

Kos, L.; Tskhakaya, D. D.

2018-01-01

The time evolution of a one-dimensional, uni-polar ion sheath (an "ion matrix sheath") is investigated. The analytical solutions for the ion-fluid and Poisson's equations are found for an arbitrary time dependence of the wall-applied negative potential. In the case that the wall potential is large and remains constant after its ramp-up application, the explicit time dependencies of the sheath's parameters during the initial stage of the process are given. The characteristic rate of approaching the stationary state, satisfying the Child-Langmuir law, is determined.

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

PubMed Central

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

Ion Dynamics Model for Collisionless Radio Frequency Sheaths

NASA Technical Reports Server (NTRS)

Bose, Deepak; Govindan, T.R.; Meyyappan, M.

2000-01-01

Full scale reactor model based on fluid equations is widely used to analyze high density plasma reactors. It is well known that the submillimeter scale sheath in front of a biased electrode supporting the wafer is difficult to resolve in numerical simulations, and the common practice is to use results for electric field from some form of analytical sheath model as boundary conditions for full scale reactor simulation. There are several sheath models in the literature ranging from Child's law to a recent unified sheath model [P. A. Miller and M. E. Riley, J. Appl. Phys. 82, 3689 (1997)l. In the present work, the cold ion fluid equations in the radio frequency sheath are solved numerically to show that the spatiotemporal variation of ion flux inside the sheath, commonly ignored in analytical models, is important in determining the electric field and ion energy at the electrode. Consequently, a semianalytical model that includes the spatiotemporal variation of ion flux is developed for use as boundary condition in reactor simulations. This semianalytical model is shown to yield results for sheath properties in close agreement with numerical solutions.

Miniature sheathed thermocouples for turbine blade temperature measurement

NASA Technical Reports Server (NTRS)

Holanda, R.; Glawe, G. E.; Krause, L. N.

1974-01-01

An investigation was made of sheathed thermocouples for turbine blade temperature measurements. Tests were performed on the Chromel-Alumel sheathed thermocouples with both two-wire and single-wire configurations. Sheath diameters ranged from 0.25 to 0.76 mm, and temperatures ranged from 1080 to 1250 K. Both steady-state and thermal cycling tests were performed for times up to 450 hr. Special-order and commercial-grade thermocouples were tested. The tests showed that special-order single-wire sheathed thermocouples can be obtained that are reliable and accurate with diameters as small as 0.25 mm. However, all samples of 0.25-mm-diameter sheathed commercial-grade two-wire and single-wire thermocouples that were tested showed unacceptable drift rates for long-duration engine testing programs. The drift rates were about 1 percent in 10 hr. A thermocouple drift test is recommended in addition to the normal acceptance tests in order to select reliable miniature sheathed thermocouples for turbine blade applications.

Benchmarking sheath subgrid boundary conditions for macroscopic-scale simulations

NASA Astrophysics Data System (ADS)

Jenkins, T. G.; Smithe, D. N.

2015-02-01

The formation of sheaths near metallic or dielectric-coated wall materials in contact with a plasma is ubiquitous, often giving rise to physical phenomena (sputtering, secondary electron emission, etc) which influence plasma properties and dynamics both near and far from the material interface. In this paper, we use first-principles PIC simulations of such interfaces to formulate a subgrid sheath boundary condition which encapsulates fundamental aspects of the sheath behavior at the interface. Such a boundary condition, based on the capacitive behavior of the sheath, is shown to be useful in fluid simulations wherein sheath scale lengths are substantially smaller than scale lengths for other relevant physical processes (e.g. radiofrequency wavelengths), in that it enables kinetic processes associated with the presence of the sheath to be numerically modeled without explicit resolution of spatial and temporal sheath scales such as electron Debye length or plasma frequency.

Rectus sheath hematoma: three case reports

PubMed Central

Kapan, Selin; Turhan, Ahmet N; Alis, Halil; Kalayci, Mustafa U; Hatipoglu, Sinan; Yigitbas, Hakan; Aygun, Ersan

2008-01-01

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. PMID:18221529

The structure of the Myo4p globular tail and its function in ASH1 mRNA localization.

PubMed

Heuck, Alexander; Fetka, Ingrid; Brewer, Daniel N; Hüls, Daniela; Munson, Mary; Jansen, Ralf-Peter; Niessing, Dierk

2010-05-03

Type V myosin (MyoV)-dependent transport of cargo is an essential process in eukaryotes. Studies on yeast and vertebrate MyoV showed that their globular tails mediate binding to the cargo complexes. In Saccharomyces cerevisiae, the MyoV motor Myo4p interacts with She3p to localize asymmetric synthesis of HO 1 (ASH1) mRNA into the bud of dividing cells. A recent study showed that localization of GFP-MS2-tethered ASH1 particles does not require the Myo4p globular tail, challenging the supposed role of this domain. We assessed ASH1 mRNA and Myo4p distribution more directly and found that their localization is impaired in cells expressing globular tail-lacking Myo4p. In vitro studies further show that the globular tail together with a more N-terminal linker region is required for efficient She3p binding. We also determined the x-ray structure of the Myo4p globular tail and identify a conserved surface patch important for She3p binding. The structure shows pronounced similarities to membrane-tethering complexes and indicates that Myo4p may not undergo auto-inhibition of its motor domain.

Resveratrol given intraperitoneally does not inhibit growth of high-risk t(4;11) acute lymphoblastic leukemia cells in NOD/SCID mouse model

USDA-ARS?s Scientific Manuscript database

The efficacy of the phytochemical resveratrol as a preventive agent against the growth of t(4;11) acute lymphoblastic leukemia (ALL) was evaluated in NOD.CB17-Prkdcscid/J mice engrafted with the human t(4;11) ALL line SEM. SEM cells were injected into the tail vein and engraftment was monitored by ...

Protective sheath for a continuous measurement thermocouple

DOEpatents

Phillippi, R. Michael

1991-01-01

Disclosed is a protective thermocouple sheath of a magnesia graphite refractory material for use in continuous temperature measurements of molten metal in a metallurgical ladle and having a basic slag layer thereon. The sheath includes an elongated torpedo-shaped sheath body formed of a refractory composition and having an interior borehole extending axially therethrough and adapted to receive a thermocouple. The sheath body includes a lower end which is closed about the borehole and forms a narrow, tapered tip. The sheath body also includes a first body portion integral with the tapered tip and having a relatively constant cross section and providing a thin wall around the borehole. The sheath body also includes a second body portion having a relatively constant cross section larger than the cross section of the first body portion and providing a thicker wall around the borehole. The borehole terminates in an open end at the second body portion. The tapered tip is adapted to penetrate the slag layer and the thicker second body portion and its magnesia constituent material are adapted to withstand chemical attack thereon from the slag layer. The graphite constituent improves thermal conductivity of the refractory material and, thus, enhances the thermal responsiveness of the device.

Bisphenol A, 4-t-octylphenol, and 4-nonylphenol determination in serum by Hybrid Solid Phase Extraction-Precipitation Technology technique tailored to liquid chromatography-tandem mass spectrometry.

PubMed

Asimakopoulos, Alexandros G; Thomaidis, Nikolaos S

2015-04-01

A rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and optimized for the simultaneous determination of bisphenol A, 4-t-octylphenol and 4-nonylphenol in human blood serum. For the first time, the electrospray ionization (ESI) parameters of probe position, voltage potential, sheath gas flow rate, auxiliary gas flow rate, and ion transfer tube temperature were thoroughly studied and optimized for each phenol by a univariate approach. As a consequence, low instrumental limits of detection were reported, demonstrating at 0.2 ng/mL (in solvent matrix) excellent injection repeatability (RSD<14.5%) and a confirmation peak for all target phenols. Extraction and purification of serum was performed by the novel Hybrid Solid Phase Extraction-Precipitation Technology technique (Hybrid SPE-PPT). The limits of detection in human blood serum were 0.80, 1.3 and 1.4 ng/mL for BPA, 4-t-OP and 4-NP, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

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

PubMed

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.

Short interspersed elements (SINEs) from insectivores. Two classes of mammalian SINEs distinguished by A-rich tail structure.

PubMed

Borodulina, O R; Kramerov, D A

2001-10-01

Four tRNA-related SINE families were isolated from the genome of the shrew Sorex araneus (SOR element), mole Mogera robusta (TAL element), and hedgehog Mesechinus dauuricus (ERI-1 and ERI-2 elements). Each of these SINEs families is specific for a single Insectivora family: SOR, for Soricidae (shrews); TAL, for Talpidae (moles and desmans); ERI-1 and ERI-2, for Erinaceidae (hedgehogs). There is a long polypyrimidine region (TC-motif) in TAL, ERI-1, and ERI-2 elements located immediately upstream of an A-rich tail with polyadenylation signals (AATAAA) and an RNA polymerase III terminator (T(4-6)) or TCT(3-4)). Ten out of 14 analyzed mammalian tRNA-related SINE families have an A-rich tail similar to that of TAL, ERI-1, and ERI-2 elements. These elements were assigned to class T+. The other four SINEs including SOR element have no polyadenylation signal and transcription terminator in their A-rich tail and were assigned to class T-. Class T+ SINEs occur only in mammals, and most of them have a long polypyrimidine region. Possible models of retroposition of class T+ and T- SINEs are discussed.

A randomised trial of sheathed versus standard forceps for obtaining uncontaminated biopsy specimens of microbiota from the terminal ileum.

PubMed

Dave, Maneesh; Johnson, Laura A; Walk, Seth T; Young, Vincent B; Stidham, Ryan W; Chaudhary, Meghana N; Funnell, Jessica; Higgins, Peter D R

2011-08-01

The study of intestinal microbiota has been revolutionised by the use of molecular methods, including terminal restriction fragment length polymorphism (T-RFLP) analysis. Microbiota studies of Crohn's disease patients have examined samples from stool or from the neoterminal ileum with a standard biopsy forceps, which could be contaminated by colonic bacteria when the forceps passes through the colonoscope channel. To determine whether sheathed biopsy forceps are able to obtain terminal ileal microbiota samples with less colonic bacterial contamination compared with unsheathed (standard) biopsy forceps. Prospective randomised single-centre study. Four (paired) biopsy specimens were obtained from adjacent locations in the terminal ileum using the sheathed and standard forceps of 27 consecutive subjects undergoing colonoscopy and the microbiota were characterised using T-RFLP. The Bray-Curtis similarity index between samples (sheathed vs unsheathed forceps) was calculated within patients and significant differences were tested for across all patients. There was not a significant difference in the microbial diversity of samples obtained using sheathed versus unsheathed forceps. The difference in microbial diversity between patients was much greater than the variability within patients by proximal versus distal site or by forceps type. T-RFLP is based on PCR amplification, so it is not always sensitive to rare bacterial species. Standard unsheathed forceps appear to be sufficient for microbiota sample collection from the terminal ileum.

Attic construction with sheathing-applied insulation

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

Rose, W.B.

1995-12-31

Two years of study at a building research laboratory have been applied to cathedralized residential attic construction. Cathedralized attics are rafter-framed or truss-framed attics with flat ceilings in which the insulation is placed against the underside of the roof sheathing rather than on top of the ceiling drywall. The potential benefits of sheathing-applied insulation are considerable and are due to the fact that the attic space becomes part of the conditioned volume. Concern is often expressed that moisture damage may occur in the sheathing. The intent of the current study was to address those concerns. This study allowed an assessmentmore » of the performance of cathedralized ceilings, given the following construction variables: (1) ventilation vs. no ventilation, (2) continuous air chute construction vs. stuffed insulation construction, and (3) opens joints in exposed kraft facing vs. taped joints. The results were compared to a concurrent study of the performance of cathedral ceilings with sloped ceiling drywall. The results show that having an air chute that ensures an air gap between the sheathing and the top of the insulation is the critical factor. Ventilation and the taping of joints were minor determinants of the moisture performance of the sheathing. These results are consistent with the results of normal cathedral ceiling construction performance.« less

15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH

PubMed Central

2016-01-01

15N nuclear spins of imidazole-15N2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole-15N2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15N site of imidazole occurs at physiological pH (pKa ∼ 7.0), and the binding event changes the 15N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms. PMID:27379344

15N Hyperpolarization of Imidazole-15N2 for Magnetic Resonance pH Sensing via SABRE-SHEATH.

PubMed

Shchepin, Roman V; Barskiy, Danila A; Coffey, Aaron M; Theis, Thomas; Shi, Fan; Warren, Warren S; Goodson, Boyd M; Chekmenev, Eduard Y

2016-06-24

15 N nuclear spins of imidazole- 15 N 2 were hyperpolarized using NMR signal amplification by reversible exchange in shield enables alignment transfer to heteronuclei (SABRE-SHEATH). A 15 N NMR signal enhancement of ∼2000-fold at 9.4 T is reported using parahydrogen gas (∼50% para-) and ∼0.1 M imidazole- 15 N 2 in methanol:aqueous buffer (∼1:1). Proton binding to a 15 N site of imidazole occurs at physiological pH (p K a ∼ 7.0), and the binding event changes the 15 N isotropic chemical shift by ∼30 ppm. These properties are ideal for in vivo pH sensing. Additionally, imidazoles have low toxicity and are readily incorporated into a wide range of biomolecules. 15 N-Imidazole SABRE-SHEATH hyperpolarization potentially enables pH sensing on scales ranging from peptide and protein molecules to living organisms.

Porous protective solid phase micro-extractor sheath

DOEpatents

Andresen, Brian D.; Randich, Erik

2005-03-29

A porous protective sheath for active extraction media used in solid phase microextraction (SPME). The sheath permits exposure of the media to the environment without the necessity of extending a fragile coated fiber from a protective tube or needle. Subsequently, the sheath can pierce and seal with GC-MS septums, allowing direct injection of samples into inlet ports of analytical equipment. Use of the porous protective sheath, within which the active extraction media is contained, mitigates the problems of: 1) fiber breakage while the fiber is extended during sampling, 2) active media coating loss caused by physical contact of the bare fiber with the sampling environment; and 3) coating slough-off during fiber extension and retraction operations caused by rubbing action between the fiber and protective needle or tube.

Affinity Map of Bromodomain Protein 4 (BRD4) Interactions with the Histone H4 Tail and the Small Molecule Inhibitor JQ1*

PubMed Central

Jung, Marie; Philpott, Martin; Müller, Susanne; Schulze, Jessica; Badock, Volker; Eberspächer, Uwe; Moosmayer, Dieter; Bader, Benjamin; Schmees, Norbert; Fernández-Montalván, Amaury; Haendler, Bernard

2014-01-01

Bromodomain protein 4 (BRD4) is a member of the bromodomain and extra-terminal domain (BET) protein family. It binds to acetylated histone tails via its tandem bromodomains BD1 and BD2 and forms a complex with the positive transcription elongation factor b, which controls phosphorylation of RNA polymerase II, ultimately leading to stimulation of transcription elongation. An essential role of BRD4 in cell proliferation and cancer growth has been reported in several recent studies. We analyzed the binding of BRD4 BD1 and BD2 to different partners and showed that the strongest interactions took place with di- and tetra-acetylated peptides derived from the histone 4 N-terminal tail. We also found that several histone 4 residues neighboring the acetylated lysines significantly influenced binding. We generated 10 different BRD4 BD1 mutants and analyzed their affinities to acetylated histone tails and to the BET inhibitor JQ1 using several complementary biochemical and biophysical methods. The impact of these mutations was confirmed in a cellular environment. Altogether, the results show that Trp-81, Tyr-97, Asn-140, and Met-149 play similarly important roles in the recognition of acetylated histones and JQ1. Pro-82, Leu-94, Asp-145, and Ile-146 have a more differentiated role, suggesting that different kinds of interactions take place and that resistance mutations compatible with BRD4 function are possible. Our study extends the knowledge on the contribution of individual BRD4 amino acids to histone and JQ1 binding and may help in the design of new BET antagonists with improved pharmacological properties. PMID:24497639

Spontaneous rectus sheath hematoma in pregnancy and a systematic anatomical workup of rectus sheath hematoma: a case report.

PubMed

Eckhoff, Kerstin; Wedel, Thilo; Both, Marcus; Bas, Kayhan; Maass, Nicolai; Alkatout, Ibrahim

2016-10-19

Rectus sheath hematoma is a rare clinical diagnosis, particularly in pregnancy. Due to unspecific symptoms, misdiagnosis is likely and could potentially endanger a patient as well as her fetus. A 26-year-old white woman presented with mild right-sided abdominal pain, which increased during palpation and movement, at 26 + 3 weeks' gestational age. Ultrasound imaging initially showed a round and well-demarcated structure, which appeared to be in contact with her uterine wall, leading to a suspected diagnosis of an infarcted leiomyoma. However, she reported increasing levels of pain and laboratory tests showed a significant drop in her initially normal hemoglobin level. A magnetic resonance imaging scan finally revealed a large type III rectus sheath hematoma on the right side. Because of progressive blood loss into her rectus sheath under conservative therapy, with a significant further decrease in her hemoglobin levels, surgical treatment via right-sided paramedian laparotomy was initiated. During the operation the arterial bleed could be ligated. She eventually achieved complete convalescence and delivered a healthy newborn spontaneously after 40 weeks of gestation. This case report highlights the clinical and diagnostic features of rectus sheath hematoma and shows the anatomical aspects of the rectus sheath, simplifying early and correct diagnosis.

Isoguanine quartets formed by d(T4isoG4T4): tetraplex identification and stability.

PubMed Central

Seela, F; Wei, C; Melenewski, A

1996-01-01

The self-aggregation of the oligonucleotide d(T4isoG4T4) (1) is investigated. Based on ion exchange HPLC experiments and CD spectroscopy, a tetrameric structure is identified. This structure was formed in the presence of sodium ions and shows almost the same chromatographic mobility on ion exchange HPLC as d(T4G4T4) (2). The ratio of aggregate versus monomer is temperature dependent and the tetraplex of [d(T4isoG4T4)]4 is more stable than that of [d(T4G4T4)]4. A mixture of d(T4isoG4T4) and d(T4G4T4) forms mixed tetraplexes containing strands of d(T4isoG4T4) and d(T4G4T4). PMID:9016664

The complete mitochondrial genome of the tiger tail seahorse, Hippocampus comes (Teleostei, Syngnathidae).

PubMed

Chang, Chia-Hao; Lin, Han-Yang; Jang-Liaw, Nian-Hong; Shao, Kwang-Tsao; Lin, Yeong-Shin; Ho, Hsuan-Ching

2013-06-01

The complete mitochondrial genome of the tiger tail seahorse was sequenced using a polymerase chain reaction-based method. The total length of mitochondrial DNA is 16,525 bp and includes 13 protein-coding genes, 2 ribosomal RNA, 22 transfer RNA genes, and a control region. The mitochondrial gene arrangement of the tiger tail seahorse is also matching the one observed in the most vertebrate creatures. Base composition of the genome is A (32.8%), T (29.8%), C (23.0%), and G (14.4%) with an A+T-rich hallmark as that of other vertebrate mitochondrial genomes.

A Randomized Trial of Sheathed vs. Standard Forceps for Obtaining Uncontaminated Biopsy Specimens of Microbiota from the Terminal Ileum

PubMed Central

Dave, Maneesh; Johnson, Laura A.; Walk, Seth; Young, Vincent B.; Stidham, Ryan W.; Chaudhary, Meghana N.; FunNell, Jessica; Higgins, Peter D.R.

2014-01-01

Background The study of intestinal microbiota has been revolutionized by the use of molecular methods, including terminal restriction fragment length polymorphism (T-RFLP) analysis. A number of microbiota studies of Crohn’s disease patients have examined samples from stool or from the neoterminal ileum with a standard biopsy forceps, which could be contaminated by colonic bacteria when the forceps passes through the colonoscope channel. Objective To determine whether sheathed biopsy forceps are able to obtain terminal ileal microbiota samples with less colonic bacterial contamination compared to unsheathed (standard) biopsy forceps. Design Prospective randomized single center-study. Patients and Methods We obtained four (paired) biopsy specimens from adjacent locations in the terminal ileum using the sheathed and standard forceps of 27 consecutive subjects undergoing colonoscopy and characterized the microbiota using T-RFLP. We calculated the Bray Curtis similarity index (BCI) between samples (sheathed vs. unsheathed forceps) within patients and tested for significant differences across all patients. Results There was not a significant difference in the microbial diversity of samples obtained using sheathed vs. unsheathed forceps. The difference in microbial diversity between patients was much greater than the variability within patients by proximal vs. distal site or by forceps type. Limitations T-RFLP is based on PCR amplification, so it is not always sensitive to rare bacterial species. Conclusion Standard unsheathed forceps appear to be sufficient for microbiota sample collection from the terminal ileum. PMID:21317176

Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons.

PubMed

Nakatsutsumi, M; Sentoku, Y; Korzhimanov, A; Chen, S N; Buffechoux, S; Kon, A; Atherton, B; Audebert, P; Geissel, M; Hurd, L; Kimmel, M; Rambo, P; Schollmeier, M; Schwarz, J; Starodubtsev, M; Gremillet, L; Kodama, R; Fuchs, J

2018-01-18

High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated in such fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that magnetostatic fields self-generated on the target surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those fields can be strong enough (~10 5  T at laser intensities ~10 21  W cm -2 ) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire.

Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons

DOE PAGES

Nakatsutsumi, M.; Sentoku, Y.; Korzhimanov, A.; ...

2018-01-18

High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated in such fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that magnetostatic fields self-generated on the targetmore » surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those fields can be strong enough (~10 5 T at laser intensities ~10 21 W cm –2) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire.« less

Self-generated surface magnetic fields inhibit laser-driven sheath acceleration of high-energy protons

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

Nakatsutsumi, M.; Sentoku, Y.; Korzhimanov, A.

High-intensity lasers interacting with solid foils produce copious numbers of relativistic electrons, which in turn create strong sheath electric fields around the target. The proton beams accelerated in such fields have remarkable properties, enabling ultrafast radiography of plasma phenomena or isochoric heating of dense materials. In view of longer-term multidisciplinary purposes (e.g., spallation neutron sources or cancer therapy), the current challenge is to achieve proton energies well in excess of 100 MeV, which is commonly thought to be possible by raising the on-target laser intensity. Here we present experimental and numerical results demonstrating that magnetostatic fields self-generated on the targetmore » surface may pose a fundamental limit to sheath-driven ion acceleration for high enough laser intensities. Those fields can be strong enough (~10 5 T at laser intensities ~10 21 W cm –2) to magnetize the sheath electrons and deflect protons off the accelerating region, hence degrading the maximum energy the latter can acquire.« less

Laser Diagnostic Method for Plasma Sheath Potential Mapping

NASA Astrophysics Data System (ADS)

Walsh, Sean P.

Electric propulsion systems are gaining popularity in the aerospace field as a viable option for long term positioning and thrusting applications. In particular, Hall thrusters have shown promise as the primary propulsion engine for space probes during interplanetary journeys. However, the interaction between propellant xenon ions and the ceramic channel wall continues to remain a complex issue. The most significant source of power loss in Hall thrusters is due to electron and ion currents through the sheath to the channel wall. A sheath is a region of high electric field that separates a plasma from a wall or surface in contact. Plasma electrons with enough energy to penetrate the sheath may result emission of a secondary electron from the wall. With significant secondary electron emission (SEE), the sheath voltage is reduced and so too is the electron retarding electric field. Therefore, a lower sheath voltage further increases the particle loss to the wall of a Hall thruster and leads to plasma cooling and lower efficiency. To further understand sheath dynamics, laser-induced fluorescence is employed to provide a non-invasive, in situ, and spatially resolved technique for measuring xenon ion velocity. By scanning the laser wavelength over an electronic transition of singly ionized xenon and collecting the resulting fluorescence, one can determine the ion velocity from the Doppler shifted absorption. Knowing the velocity at multiple points in the sheath, it can be converted to a relative electric potential profile which can reveal a lot about the plasma-wall interaction and the severity of SEE. The challenge of adequately measuring sheath potential profiles is optimizing the experiment to maximize the signal-to-noise ratio. A strong signal with low noise, enables high resolution measurements and increases the depth of measurement in the sheath, where the signal strength is lowest. Many improvements were made to reduce the background luminosity, increase the

Farris-Tang retractor in optic nerve sheath decompression surgery.

PubMed

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.

Characteristics of Electronegative Plasma Sheath with q-Nonextensive Electron Distribution

NASA Astrophysics Data System (ADS)

Borgohain, D. R.; Saharia, K.

2018-01-01

The characteristics of sheath in a plasma system containing q-nonextensive electrons, cold fluid ions, and Boltzmann-distributed negative ions are investigated. A modified Bohm sheath criterion is derived by using the Sagdeev pseudopotential technique. It is found that the proposed Bohm velocity depends on the degree of nonextensivity ( q), negative ion temperature to nonextensive electron temperature ratio (σ), and negative ion density ( B). Using the modified Bohm sheath criterion, the sheath characteristics, such as the spatial distribution of the potential, positive ion velocity, and density profile, have been numerically investigated, which clearly shows the effect of negative ions, as well as the nonextensive distribution of electrons. It is found that, as the nonextensivity parameter and the electronegativity increases, the electrostatic sheath potential increases sharply and the sheath width decreases.

Poly A tail length analysis of in vitro transcribed mRNA by LC-MS.

PubMed

Beverly, Michael; Hagen, Caitlin; Slack, Olga

2018-02-01

The 3'-polyadenosine (poly A) tail of in vitro transcribed (IVT) mRNA was studied using liquid chromatography coupled to mass spectrometry (LC-MS). Poly A tails were cleaved from the mRNA using ribonuclease T1 followed by isolation with dT magnetic beads. Extracted tails were then analyzed by LC-MS which provided tail length information at single-nucleotide resolution. A 2100-nt mRNA with plasmid-encoded poly A tail lengths of either 27, 64, 100, or 117 nucleotides was used for these studies as enzymatically added poly A tails showed significant length heterogeneity. The number of As observed in the tails closely matched Sanger sequencing results of the DNA template, and even minor plasmid populations with sequence variations were detected. When the plasmid sequence contained a discreet number of poly As in the tail, analysis revealed a distribution that included tails longer than the encoded tail lengths. These observations were consistent with transcriptional slippage of T7 RNAP taking place within a poly A sequence. The type of RNAP did not alter the observed tail distribution, and comparison of T3, T7, and SP6 showed all three RNAPs produced equivalent tail length distributions. The addition of a sequence at the 3' end of the poly A tail did, however, produce narrower tail length distributions which supports a previously described model of slippage where the 3' end can be locked in place by having a G or C after the poly nucleotide region. Graphical abstract Determination of mRNA poly A tail length using magnetic beads and LC-MS.

Gas insulated transmission line having low inductance intercalated sheath

DOEpatents

Cookson, Alan H.

1978-01-01

A gas insulated transmission line including an outer sheath, an inner conductor disposed within the outer sheath, and an insulating gas between the inner conductor and the outer sheath. The outer sheath comprises an insulating tube having first and second ends, and having interior and exterior surfaces. A first electrically conducting foil is secured to the interior surface of the insulating tube, is spirally wound from one tube end to the second tube end, and has a plurality of overlapping turns. A second electrically conducting foil is secured to the exterior surface of the insulating tube, and is spirally wound in the opposite direction from the first electrically conducting foil. By winding the foils in opposite directions, the inductances within the intercalated sheath will cancel each other out.

Effect of collisions on photoelectron sheath in a gas

NASA Astrophysics Data System (ADS)

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.

Amino group in Leptothrix sheath skeleton is responsible for direct deposition of Fe(III) minerals onto the sheaths.

PubMed

Kunoh, Tatsuki; Matsumoto, Syuji; Nagaoka, Noriyuki; Kanashima, Shoko; Hino, Katsuhiko; Uchida, Tetsuya; Tamura, Katsunori; Kunoh, Hitoshi; Takada, Jun

2017-07-26

Leptothrix species produce microtubular organic-inorganic materials that encase the bacterial cells. The skeleton of an immature sheath, consisting of organic exopolymer fibrils of bacterial origin, is formed first, then the sheath becomes encrusted with inorganic material. Functional carboxyl groups of polysaccharides in these fibrils are considered to attract and bind metal cations, including Fe(III) and Fe(III)-mineral phases onto the fibrils, but the detailed mechanism remains elusive. Here we show that NH 2 of the amino-sugar-enriched exopolymer fibrils is involved in interactions with abiotically generated Fe(III) minerals. NH 2 -specific staining of L. cholodnii OUMS1 detected a terminal NH 2 on its sheath skeleton. Masking NH 2 with specific reagents abrogated deposition of Fe(III) minerals onto fibrils. Fe(III) minerals were adsorbed on chitosan and NH 2 -coated polystyrene beads but not on cellulose and beads coated with an acetamide group. X-ray photoelectron spectroscopy at the N1s edge revealed that the terminal NH 2 of OUMS1 sheaths, chitosan and NH 2 -coated beads binds to Fe(III)-mineral phases, indicating interaction between the Fe(III) minerals and terminal NH 2 . Thus, the terminal NH 2 in the exopolymer fibrils seems critical for Fe encrustation of Leptothrix sheaths. These insights should inform artificial synthesis of highly reactive NH 2 -rich polymers for use as absorbents, catalysts and so on.

Experimental investigation of plasma sheaths in magnetic mirror and cusp configurations

NASA Astrophysics Data System (ADS)

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.

Concerted regulation of ISWI by an autoinhibitory domain and the H4 N-terminal tail

PubMed Central

Ludwigsen, Johanna; Pfennig, Sabrina; Singh, Ashish K; Schindler, Christina; Harrer, Nadine; Forné, Ignasi; Zacharias, Martin; Mueller-Planitz, Felix

2017-01-01

ISWI-family nucleosome remodeling enzymes need the histone H4 N-terminal tail to mobilize nucleosomes. Here we mapped the H4-tail binding pocket of ISWI. Surprisingly the binding site was adjacent to but not overlapping with the docking site of an auto-regulatory motif, AutoN, in the N-terminal region (NTR) of ISWI, indicating that AutoN does not act as a simple pseudosubstrate as suggested previously. Rather, AutoN cooperated with a hitherto uncharacterized motif, termed AcidicN, to confer H4-tail sensitivity and discriminate between DNA and nucleosomes. A third motif in the NTR, ppHSA, was functionally required in vivo and provided structural stability by clamping the NTR to Lobe 2 of the ATPase domain. This configuration is reminiscent of Chd1 even though Chd1 contains an unrelated NTR. Our results shed light on the intricate structural and functional regulation of ISWI by the NTR and uncover surprising parallels with Chd1. DOI: http://dx.doi.org/10.7554/eLife.21477.001 PMID:28109157

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

NASA Astrophysics Data System (ADS)

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.

Compensation of the sheath effects in cylindrical floating probes

NASA Astrophysics Data System (ADS)

Park, Ji-Hwan; Chung, Chin-Wook

2018-05-01

In cylindrical floating probe measurements, the plasma density and electron temperature are overestimated due to sheath expansion and oscillation. To reduce these sheath effects, a compensation method based on well-developed floating sheath theories is proposed and applied to the floating harmonic method. The iterative calculation of the Allen-Boyd-Reynolds equation can derive the floating sheath thickness, which can be used to calculate the effective ion collection area; in this way, an accurate ion density is obtained. The Child-Langmuir law is used to calculate the ion harmonic currents caused by sheath oscillation of the alternating-voltage-biased probe tip. Accurate plasma parameters can be obtained by subtracting these ion harmonic currents from the total measured harmonic currents. Herein, the measurement principles and compensation method are discussed in detail and an experimental demonstration is presented.

The Tail-Elicited Tail Withdrawal Reflex of "Aplysia" Is Mediated Centrally at Tail Sensory-Motor Synapses and Exhibits Sensitization across Multiple Temporal Domains

ERIC Educational Resources Information Center

Philips, Gary T.; Sherff, Carolyn M.; Menges, Steven A.; Carew, Thomas J.

2011-01-01

The defensive withdrawal reflexes of "Aplysia californica" have provided powerful behavioral systems for studying the cellular and molecular basis of memory formation. Among these reflexes the (T-TWR) has been especially useful. In vitro studies examining the monosynaptic circuit for the T-TWR, the tail sensory-motor (SN-MN) synapses, have…

What is the size of a floating sheath? An answer

NASA Astrophysics Data System (ADS)

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.

Structure of MyTH4-FERM domains in myosin VIIa tail bound to cargo.

PubMed

Wu, Lin; Pan, Lifeng; Wei, Zhiyi; Zhang, Mingjie

2011-02-11

The unconventional myosin VIIa (MYO7A) is one of the five proteins that form a network of complexes involved in formation of stereocilia. Defects in these proteins cause syndromic deaf-blindness in humans [Usher syndrome I (USH1)]. Many disease-causing mutations occur in myosin tail homology 4-protein 4.1, ezrin, radixin, moesin (MyTH4-FERM) domains in the myosin tail that binds to another USH1 protein, Sans. We report the crystal structure of MYO7A MyTH4-FERM domains in complex with the central domain (CEN) of Sans at 2.8 angstrom resolution. The MyTH4 and FERM domains form an integral structural and functional supramodule binding to two highly conserved segments (CEN1 and 2) of Sans. The MyTH4-FERM/CEN complex structure provides mechanistic explanations for known deafness-causing mutations in MYO7A MyTH4-FERM. The structure will also facilitate mechanistic and functional studies of MyTH4-FERM domains in other myosins.

Spontaneous intraperitoneal rupture of a postpartum rectus sheath haematoma.

PubMed

Elmoghrabi, Adel; Mohamed, Mohamed; McCann, Michael; Sachwani-Daswani, Gul

2016-03-09

A 35-year-old woman presented to the emergency department (ED) with acute severe abdominal pain at 4 days postpartum. CT of the abdomen revealed a type II rectus sheath haematoma for which she was initially treated conservatively and discharged. A few hours later, she returned to the ED with a picture suggestive of peritonitis. Exploratory laparoscopy was performed and revealed haemoperitoneum and a ruptured area on the posterior rectus sheath. Approximately 2 L of blood was aspirated. Haemostatic control was achieved and closed suction drains secured in position. The patient was discharged in stable condition on postadmission day 6. She continued to follow-up on an outpatient basis and was doing well 3 months postoperatively. 2016 BMJ Publishing Group Ltd.

Spontaneous intraperitoneal rupture of a postpartum rectus sheath haematoma

PubMed Central

Elmoghrabi, Adel; McCann, Michael; Sachwani-Daswani, Gul

2016-01-01

A 35-year-old woman presented to the emergency department (ED) with acute severe abdominal pain at 4 days postpartum. CT of the abdomen revealed a type II rectus sheath haematoma for which she was initially treated conservatively and discharged. A few hours later, she returned to the ED with a picture suggestive of peritonitis. Exploratory laparoscopy was performed and revealed haemoperitoneum and a ruptured area on the posterior rectus sheath. Approximately 2 L of blood was aspirated. Haemostatic control was achieved and closed suction drains secured in position. The patient was discharged in stable condition on postadmission day 6. She continued to follow-up on an outpatient basis and was doing well 3 months postoperatively. PMID:26961567

A recombinant tail-less integrin beta 4 subunit disrupts hemidesmosomes, but does not suppress alpha 6 beta 4-mediated cell adhesion to laminins

PubMed Central

1995-01-01

To examine the function of the alpha 6 beta 4 integrin we have determined its ligand-binding ability and overexpressed two potentially dominant negative mutant beta 4 subunits, lacking either the cytoplasmic or extracellular domain, in bladder epithelial 804G cells. The results of cell adhesion and radioligand-binding assays showed that alpha 6 beta 4 is a receptor for several laminin isoforms, including laminin 1, 2, 4, and 5. Overexpression of the tail-less or head-less mutant beta 4 subunit did not suppress alpha 6 beta 4-mediated adhesion to laminins, as both types of transfectants adhered to these ligands in the presence of blocking anti-beta 1 antibodies as well as the controls. However, immunofluorescence experiments indicated that the endogenous alpha 6 beta 4 integrin and other hemidesmosomal markers were not concentrated in hemidesmosomes in cells overexpressing tail- less beta 4, while the distribution of these molecules was not altered in cells overexpressing the head-less subunit. Electron microscopic studies confirmed that cells overexpressing tail-less beta 4 had a drastically reduced number of hemidesmosomes, while cells expressing the head-less subunit had a normal number of these structures. Thus, expression of a tail-less, but not a head-less mutant beta 4 subunit leads to a dominant negative effect on hemidesmosome assembly without suppressing initial adhesion to laminins. We conclude that the alpha 6 beta 4 integrin binds to several laminins and plays an essential role in the assembly and/or stability of hemidesmosomes, that alpha 6 beta 4- mediated adhesion and hemidesmosome assembly have distinct requirements, and that it is possible to use a dominant negative approach to selectively interfere with a specific function of an integrin. PMID:7721947

Lung biopsy with a 12-gauge cutting needle is possible using an insertion sheath in animal models.

PubMed

Izumi, Yotaro; Oyama, Takahiko; Kawamura, Masafumi; Kobayashi, Koichi

2004-11-01

The volume of lung tumor core biopsy specimens has been restricted because of concerns for complications such as bleeding and air leakage. In this animal experiment, we investigated the possibility of larger bore biopsies through the peripheral lung parenchyma. Lung biopsy was done in male domestic pigs (n= 4) under thoracotomy. A single biopsy using a 12-gauge cutting biopsy needle was done with sheath (sheath group, eight biopsies) or without sheath (nonsheath group, eight biopsies). After biopsy, bleeding time, bleeding amount, and positive airway pressure causing air leakage from the insertion site was compared between groups (Mann-Whitney U test). To observe long-term effects in closed-chest animals, percutaneous lung biopsy with the use of a sheath was carried out percutaneously in male beagles (n = 9). The animals were observed for 3 weeks. In the pigs (sheath group) after biopsy, bleeding flowed through the sheath and formed a sheath-molded fibrin plug that secured the insertion site. Bleeding time and amount decreased significantly in the sheath group compared with the nonsheath group (115 +/- 108 versus 295 +/- 150 seconds, P = .018, and 37 +/- 41 versus 98 +/- 72 grams, P= .027, respectively). Air leakage pressure was significantly higher in the sheath group compared with the nonsheath group (37 +/- 6 versus 18 +/- 5 cmH2O, P = .001). In the beagles, no complications such as pneumothorax, hemothorax, or airway bleeding was apparent. Although we have not evaluated lung tumor biopsy per se, lung tumor biopsy with a 12-gauge cutting needle may be possible with a use of a sheath.

Rectus Sheath Hematoma Associated with Apixaban.

PubMed

Gunasekaran, Kulothungan; Winans, Amanda R McFee; Murthi, Swetha; Ahmad, Mudassar Raees; Kaatz, Scott

2017-06-07

Apixaban is an oral anticoagulant that directly inhibits Factor Xa and is indicated for the prophylaxis and treatment of deep venous thrombosis and stroke prevention in non-valvular atrial fibrillation. Rectus sheath hematoma is a rare, life-threatening complication of anticoagulant treatment. We describe a case of an elderly patient on apixaban for the treatment of deep venous thrombosis who developed severe abdominal pain during hospitalization. Computed tomography of the abdomen revealed left rectus sheath hematoma. Apixaban was discontinued and the patient was monitored for extension of the hematoma. After 2 days she was discharged home. Outpatient computed tomography 1 month later showed complete resolution of the rectus sheath hematoma. We recommend that clinicians become aware of the potential for rare and serious bleeding complications of anticoagulants and identify the need for early recognition and prompt management.

Plasma wall sheath contributions to flux retention during the formation of field-reversed configurations

NASA Astrophysics Data System (ADS)

Milroy, R. D.; Slough, J. T.; Hoffman, A. L.

1984-06-01

Flux loss during field reversal on the TRX-1 field-reversed θ pinch is found to be much less than predicted by the inertial model of Green and Newton. This can be explained by a pressure bearing, conducting sheath which naturally forms at the wall and limits the flux loss. A one-dimensional (r-t) magnetohydrodynamic (MHD) numerical model has been used to study the formation and effectiveness of the sheath. The calculations are in excellent agreement with experimental measurements over a wide range of operating parameters. The results indicate that good flux trapping can be achieved through the field reversal phase of FRC formation with much slower external field reversal rates than in current experiments.

The quantitative role of flexor sheath incision in correcting Dupuytren proximal interphalangeal joint contractures.

PubMed

Blazar, P E; Floyd, E W; Earp, B E

2016-07-01

Controversy exists regarding intra-operative treatment of residual proximal interphalangeal joint contractures after Dupuytren's fasciectomy. We test the hypothesis that a simple release of the digital flexor sheath can correct residual fixed flexion contracture after subtotal fasciectomy. We prospectively enrolled 19 patients (22 digits) with Dupuytren's contracture of the proximal interphalangeal joint. The average pre-operative extension deficit of the proximal interphalangeal joints was 58° (range 30-90). The flexion contracture of the joint was corrected to an average of 28° after fasciectomy. In most digits (20 of 21), subsequent incision of the flexor sheath further corrected the contracture by an average of 23°, resulting in correction to an average flexion contracture of 4.7° (range 0-40). Our results support that contracture of the tendon sheath is a contributor to Dupuytren's contracture of the joint and that sheath release is a simple, low morbidity addition to correct Dupuytren's contractures of the proximal interphalangeal joint. Additional release of the proximal interphalangeal joint after fasciectomy, after release of the flexor sheath, is not necessary in many patients. IV (Case Series, Therapeutic). © The Author(s) 2015.

The magnetized sheath of a dusty plasma with grains size distribution

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

Ou, Jing, E-mail: ouj@ipp.ac.cn; Gan, Chunyun; Lin, Binbin

2015-05-15

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 valuemore » 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.« less

Two-Tailed Comet Assay (2T-Comet): Simultaneous Detection of DNA Single and Double Strand Breaks.

PubMed

Cortés-Gutiérrez, Elva I; Fernández, José Luis; Dávila-Rodríguez, Martha I; López-Fernández, Carmen; Gosálvez, Jaime

2017-01-01

A modification of the original comet assay was developed for the simultaneous evaluation of DNA single strand breaks (SSBs) and double strand breaks (DSBs) in human spermatozoa. The two-dimensional perpendicular tail comet assay (2T-comet) combines non-denaturing and denaturant conditions to the same sperm nucleoid. In this case, the species-specific deproteinized sperm is first subjected to an electrophoretic field under non-denaturing conditions to mobilize isolated free discrete DNA fragments produced from DSBs; this is then followed by a second electrophoresis running perpendicular to the first one but under alkaline conditions to produce DNA denaturation, exposing SSBs on the same linear DNA chain or DNA fragments flanked by DSBs. This procedure results in a two dimensional comet tail emerging from the core where two types of original DNA affected molecule can be simultaneously discriminated. The 2T-comet is a fast, sensitive, and reliable procedure to distinguish between single and double strand DNA damage within the same cell. It is an innovative method for assessing sperm DNA integrity, which has important implications for human fertility and andrological pathology. This technique may be adapted to assess different DNA break types in other species and other cell types.

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

NASA Astrophysics Data System (ADS)

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.

[Ultrasound-guided rectus sheath block for upper abdominal surgery].

PubMed

Osaka, Yoshimune; Kashiwagi, Masanori; Nagatsuka, Yukio; Oosaku, Masayoshi; Hirose, Chikako

2010-08-01

Upper abdominal surgery leads to severe postoperative pain. Insufficient postoperative analgesia accompanies a high incidence of complications. Therefore, postoperative analgesia is very important. The epidural analgesia has many advantages. However it has a high risk of epidural hematoma in anticoagulated patients. Rectus sheath block provided safer and more reliable analgesia in recent years, by the development of ultrasound tools. We experienced two cases of the rectus sheath block in upper abdominal surgery under ultrasound guidance. Ultrasound guided rectus sheath block can reduce the risk of peritoneal puncture, bleeding, and other complications. Rectus sheath block is very effective to reduce postoperative pain in upper abdominal surgery as an alternative method to epidural anesthesia in anticoagulated patients.

Current sheath behavior and its velocity enhancement in a low energy Mather-type plasma focus device

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

Aghamir, F. M.; Behbahani, R. A.

The dynamics of the plasma sheath layer and its velocity enhancement have been studied in a low energy (4.9 kJ) Mather-type plasma focus device. Experiments were performed to study the effect of the Lorentz force variation on the current sheath expansion and movement, as well as the existence of traction between all parts of the sheath layer. Two different shape of anodes (cylindrical and step) along with an axial magnetic probe were used to investigate the effects of various experimental conditions, namely different charging voltages and gas pressures. In order to explore the upper limit of the current sheath velocity,more » a comparison has been made between the experimental data gathered by the probe and the Lee's computational model. The limitations governing the enhancement of the current sheath velocity that can lead to the deterioration of a good focusing phenomenon were also investigated. The increase of the current sheath velocity due to the usage of the step anode on ion generation and hard x-ray emissions have been demonstrated by means of an ion collector and a hard x-ray detector.« less

Dielectric relaxation in undiluted poly (4-chlorostyrene). II. Characteristics of the high frequency tail

NASA Astrophysics Data System (ADS)

Yoshihara, M.; Work, R. N.

1981-05-01

The shape of the principal dielectric relaxation process that occurs just above the glass transition temperature Tg in well annealed, atactic, undiluted poly (4-chlorostyrene) exhibits a small tail at the high frequency end of the spectrum of relaxation times. This high frequency tail (HFT) has been characterized at temperatures varying from 351 to 413 K by using the Havriliak-Negami equation. The glass transition temperature Tg of P4CS is about 400 K. It is suggested that the HFT is distinct from the β relaxation process which occurs in polystyrene at temperatures just below Tg; and that the HFT is experimental evidence of the existence of localized, fast conformational changes. This fast process is presumed to be slowed and broadened by interactions with the surroundings.

The Tubular Sheaths Encasing Methanosaeta thermophila Filaments Are Functional Amyloids.

PubMed

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.

The Tubular Sheaths Encasing Methanosaeta thermophila Filaments Are Functional Amyloids*

PubMed Central

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

2015-01-01

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. PMID:26109065

Impact of steerable sheaths on contact forces and reconnection sites in ablation for persistent atrial fibrillation.

PubMed

Ullah, Waqas; Hunter, Ross J; McLean, Ailsa; Dhinoja, Mehul; Earley, Mark J; Sporton, Simon; Schilling, Richard J

2015-03-01

In preclinical studies, catheter contact force (CF) during radiofrequency ablation correlates with the subsequent lesion size. We investigated the impact of steerable sheaths on ablation CF, its consistency, and wide area circumferential ablation (WACA) line reconnection sites. Five thousand and sixty-four ablations were analyzed across 60 patients undergoing first-time ablation for persistent AF using a CF-sensing catheter: 19 manual nonsteerable sheath (Manual-NSS), 11 manual steerable sheath, and 30 robotic steerable sheath (Sensei, Hansen Medical Inc.) procedures were studied. Ablation CFs were higher in the steerable sheath groups for all left atrial ablations and also WACA ablations specifically (P < 0.006), but less consistent per WACA segment (P < 0.005). There were significant differences in the CFs around both WACAs by group: in the left WACA CFs were lower with Manual-NSS, other than at the anterior-inferior and posterior-superior regions, and lower in the right WACA, other than the anterior-superior region. There was a difference in the proportion of segments chronically reconnecting across groups: Manual-NSS 26.5%, manual steerable sheath 4.6%, robotic 12% (P < 0.0005). The left atrial appendage/PV ridge and right posterior wall were common sites of reconnection in all groups. Steerable sheaths increased ablation CF; however, there were region-specific heterogeneities in the extent of increment, with some segments where they failed to increase CF. Steerable sheath use was associated with reduced WACA-segment reconnection. It may be that the benefits of steerable sheath use in terms of higher CFs could be translated to improved clinical outcomes if regional weaknesses of this technology are taken into account during ablation procedures. © 2014 Wiley Periodicals, Inc.

Stability of the Tonks–Langmuir discharge pre-sheath

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

Tskhakaya, D. D.; Kos, L.; Tskhakaya, D.

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 themore » 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.« less

Posterior rectus sheath hernia causing intermittent small bowel obstruction.

PubMed

Lenobel, Scott; Lenobel, Robert; Yu, Joseph

2014-09-01

A posterior rectus sheath hernia is an abdominal wall hernia that is rarely encountered. Owing to its rarity, it can be easily overlooked in the setting of a patient presenting with abdominal pain. We report a case of a posterior rectus sheath hernia that caused intermittent small bowel obstruction. The unusual aspects of this case are that the defect was large, measuring 6 cm in the transverse diameter, and that it contained small bowel within a large portion of the rectus sheath. Because the defect was large and affected nearly the entire posterior rectus sheath, it was difficult to discern on computed tomography until a small bowel obstruction developed. In this case, a limited awareness of this clinical entity contributed to the delay in diagnosis.

Posterior Rectus Sheath Hernia Causing Intermittent Small Bowel Obstruction

PubMed Central

Lenobel, Scott; Lenobel, Robert; Yu, Joseph

2014-01-01

A posterior rectus sheath hernia is an abdominal wall hernia that is rarely encountered. Owing to its rarity, it can be easily overlooked in the setting of a patient presenting with abdominal pain. We report a case of a posterior rectus sheath hernia that caused intermittent small bowel obstruction. The unusual aspects of this case are that the defect was large, measuring 6 cm in the transverse diameter, and that it contained small bowel within a large portion of the rectus sheath. Because the defect was large and affected nearly the entire posterior rectus sheath, it was difficult to discern on computed tomography until a small bowel obstruction developed. In this case, a limited awareness of this clinical entity contributed to the delay in diagnosis. PMID:25426248

The surgical rectus sheath block for post-operative analgesia: a modern approach to an established technique.

PubMed

Crosbie, Emma J; Massiah, Nadine S; Achiampong, Josephine Y; Dolling, Stuart; Slade, Richard J

2012-02-01

To describe the surgical rectus sheath block for post-operative pain relief following major gynaecological surgery. Local anaesthetic (20 ml 0.25% bupivacaine bilaterally) is administered under direct vision to the rectus sheath space at the time of closure of the anterior abdominal wall. We conducted a retrospective case note review of 98 consecutive patients undergoing major gynaecological surgery for benign or malignant disease who received either standard subcutaneous infiltration of the wound with local anaesthetic (LA, n=51) or the surgical rectus sheath block (n=47) for post-operative pain relief. (1) Pain scores on waking, (2) duration of morphine-based patient controlled analgesia (PCA), (3) quantity of morphine used during the first 48 post-operative hours and (4) length of post-operative stay. The groups were similar in age, the range of procedures performed and the type of pathology observed. Patients who received the surgical rectus sheath block had lower pain scores on waking [0 (0-1) vs. 2 (1-3), p<0.001], required less morphine post-operatively [12 mg (9-26) vs. 36 mg (30-48), p<0.001], had their PCAs discontinued earlier [24h (18-34) vs. 37 h (28-48), p<0.001] and went home earlier [4 days (3-4) vs. 5 days post-op (4-8), p<0.001] [median (interquartile range)] than patients receiving standard subcutaneous local anaesthetic into the wound. The surgical rectus sheath block appears to provide effective post-operative analgesia for patients undergoing major gynaecological surgery. A randomised controlled clinical trial is required to assess its efficacy further. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

Stiffening Sheaths for Continuum Robots.

PubMed

Langer, Marlene; Amanov, Ernar; Burgner-Kahrs, Jessica

2018-06-01

Added to their high dexterity and ability to conform to complex shapes, continuum robots can be further improved to provide safer interaction with their environment. Indeed, controlling their stiffness is one of the most challenging yet promising research topics. We propose a tubular stiffening sheath as a replaceable cover for small-diameter continuum robots to temporarily increase the stiffness in a certain configuration. In this article, we assess and compare performances of two different stiffening modalities: granular and layer jamming, provide arguments for material selection and experimental results for stiffness with respect to lateral and axial applied forces. Furthermore, we detected empirically additional effects relating sheath stiffness to material parameters and added to recent investigations in the state of the art, which are based exclusively on material roughness. Finally, we integrated the selected layer jamming material in a miniaturized sheath (13 mm outer diameter, 2.5 mm wall thickness) and covered a tendon-actuated continuum robot with it. Experimental characterization of the behavior with respect to applied external forces was performed via stiffness measurements and proved that the initial tendon-actuated continuum robot stiffness can be improved by a factor up to 24.

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

NASA Astrophysics Data System (ADS)

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.

Modeling corona sheath dynamics and effects

NASA Astrophysics Data System (ADS)

Carlson, B.; Lehtinen, N. G.

2016-12-01

The conductive lightning channel is only a centimeter or so in diameter, but charge deposited along such a narrow channel produces a large electric field that drives corona discharge in nearby air, carrying the charge outward several meters. The formation of this "corona sheath" affects a wide range of observable properties of lightning, including the overall charge carried by the channel, the shape, speed, and attenuation of impulsive currents, and the possibility of x-ray production. Simplified electrostatic and electrodynamic models of the formation of the sheath will be discussed, with results given including regions near the tip of a hypothetical channel. These results suggest that the sheath initially expands very rapidly, limiting the lifetime of the intense fields nearest the channel. The expansion gradually slows as the fields decrease, but under certain circumstances a large-scale streamer-like process can lead to enhancement of electric fields displaced from the tip of the channel, possibly suggesting a mechanism for space stem formation and leader stepping.

A radio-frequency sheath model for complex waveforms

NASA Astrophysics Data System (ADS)

Turner, M. M.; Chabert, P.

2014-04-01

Plasma sheaths driven by radio-frequency voltages occur in contexts ranging from plasma processing to magnetically confined fusion experiments. An analytical understanding of such sheaths is therefore important, both intrinsically and as an element in more elaborate theoretical structures. Radio-frequency sheaths are commonly excited by highly anharmonic waveforms, but no analytical model exists for this general case. We present a mathematically simple sheath model that is in good agreement with earlier models for single frequency excitation, yet can be solved for arbitrary excitation waveforms. As examples, we discuss dual-frequency and pulse-like waveforms. The model employs the ansatz that the time-averaged electron density is a constant fraction of the ion density. In the cases we discuss, the error introduced by this approximation is small, and in general it can be quantified through an internal consistency condition of the model. This simple and accurate model is likely to have wide application.

Power-law tails in the distribution of order imbalance

NASA Astrophysics Data System (ADS)

Zhang, Ting; Gu, Gao-Feng; Xu, Hai-Chuan; Xiong, Xiong; Chen, Wei; Zhou, Wei-Xing

2017-10-01

We investigate the probability distribution of order imbalance calculated from the order flow data of 43 Chinese stocks traded on the Shenzhen Stock Exchange. Two definitions of order imbalance are considered based on the order number and the order size. We find that the order imbalance distributions of individual stocks have power-law tails. However, the tail index fluctuates remarkably from stock to stock. We also investigate the distributions of aggregated order imbalance of all stocks at different timescales Δt. We find no clear trend in the tail index with respect Δt. All the analyses suggest that the distributions of order imbalance are asymmetric.

Self-consistent simulation of high-frequency driven plasma sheaths

NASA Astrophysics Data System (ADS)

Shihab, Mohammed; Eremin, Denis; Mussenbrock, Thomas; Brinkmann, Ralf

2011-10-01

Low pressure capacitively coupled plasmas are widely used in plasma processing and microelectronics industry. Understanding the dynamics of the boundary sheath is a fundamental problem. It controls the energy and angular distribution of ions bombarding the electrode, which in turn affects the surface reaction rate and the profile of microscopic features. In this contribution, we investigate the dynamics of plasma boundary sheaths by means of a kinetic self-consistent model, which is able to resolve the ion dynamics. Asymmetric sheath dynamics is observed for the intermediate RF regime, i.e., in the regime where the ion plasma frequency is equal to the driving frequency. The ion inertia causes an additional phase difference between the expansion and the contraction phase of the plasma sheath and an asymmetry for the ion energy distribution bimodal shape. A comparison with experimental results and particle in cell simulations is performed. Low pressure capacitively coupled plasmas are widely used in plasma processing and microelectronics industry. Understanding the dynamics of the boundary sheath is a fundamental problem. It controls the energy and angular distribution of ions bombarding the electrode, which in turn affects the surface reaction rate and the profile of microscopic features. In this contribution, we investigate the dynamics of plasma boundary sheaths by means of a kinetic self-consistent model, which is able to resolve the ion dynamics. Asymmetric sheath dynamics is observed for the intermediate RF regime, i.e., in the regime where the ion plasma frequency is equal to the driving frequency. The ion inertia causes an additional phase difference between the expansion and the contraction phase of the plasma sheath and an asymmetry for the ion energy distribution bimodal shape. A comparison with experimental results and particle in cell simulations is performed. The financial support from the Federal Ministry of Education and Research within the frame of

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

USGS Publications Warehouse

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.

Spine Patterning Is Guided by Segmentation of the Notochord Sheath.

PubMed

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

2018-02-20

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

An Everting Ureteral Access Sheath: Concepts and In Vitro Testing

NASA Astrophysics Data System (ADS)

Lee, Keith L.; Stoller, Marshall L.

2007-04-01

Ureteral access sheaths have been a recent innovation in facilitating ureteral stone surgery. Once properly placed, access sheaths allow the movement of ureteroscopes and other instruments through the ureter with minimal injury to the urothelium. However, there are shortcomings of the current device designs. Initial sheath placement requires significant force, and shear stress can injure the ureter. In addition, inadvertent advancement of the outer sheath without the inner introducer stylet can tear and avulse the ureter. A novel eversion design incorporating a lubricous film provides marked improvement over current access sheaths. In bench top and animal models, the eversion shealths require less force during advancement, cause less injury to the urothelial tissue, and have a lower potential of introducing extraneous materials (e.g., microbes) into a simulated urinary tract. While, the everting design provides important advantages over traditional non-everting designs, further preclinical and clinical trials are required.

GRMHD/RMHD Simulations and Stability of Magnetized Spine-Sheath Relativistic Jets

NASA Technical Reports Server (NTRS)

Hardee, Philip; Mizuno, Yosuke; Nishikawa, Ken-Ichi

2007-01-01

A new general relativistic magnetohydrodynamics (GRMHD ) code "RAISHIN" used to simulate jet generation by rotating and non-rotating black holes with a geometrically thin Keplarian accretion disk finds that the jet develops a spine-sheath structure in the rotating black hole case. Spine-sheath structure and strong magnetic fields significantly modify the Kelvin-Helmholtz (KH) velocity shear driven instability. The RAISHIN code has been used in its relativistic magnetohydrodynamic (RMHD) configuration to study the effects of strong magnetic fields and weakly relativistic sheath motion, cl2, on the KH instability associated with a relativistic, Y = 2.5, jet spine-sheath interaction. In the simulations sound speeds up to ? c/3 and Alfven wave speeds up to ? 0.56 c are considered. Numerical simulation results are compared to theoretical predictions from a new normal mode analysis of the RMHD equations. Increased stability of a weakly magnetized system resulting from c/2 sheath speeds and stabilization of a strongly magnetized system resulting from d 2 sheath speeds is found.

Optic nerve sheath meningiomas.

PubMed

Saeed, Peerooz; Rootman, Jack; Nugent, Robert A; White, Valerie A; Mackenzie, Ian R; Koornneef, Leo

2003-10-01

To study the natural history and growth of optic nerve sheath meningiomas and evaluate their management outcome. Clinicopathologic retrospective noncomparative case series. A retrospective study of 88 patients who were treated between 1976 and 1999 at the University of British Columbia and the University of Amsterdam. Clinical reports, imaging studies, and histopathologic findings were reviewed. The mean age at onset of symptoms was 40.3 years, and most were seen in middle-aged females. Patients typically presented with visual loss, frequently associated with optic atrophy or papilledema and occasionally optociliary shunt vessels. On imaging, the optic nerve demonstrated segmental or diffuse thickening of the sheath or globular growth. Calcification was seen in 31% of cases and was associated with slower tumor growth. Tumors with posterior components in the orbit had more frequent intracranial involvement. Intracranial extension was more frequent and had a greater growth rate in younger patients. Irregular margins in the orbit implied local invasion. A presenting visual acuity better than 20/50 correlated with longer preservation of vision. Patients who underwent radiotherapy showed improvement in their visual acuity, and tumor growth was halted. Optic sheath decompression did not preserve vision. En bloc tumor excision was associated with no detectable recurrence in contrast to debulked tumors that recurred. Meningiomas show characteristic indolent growth. Management therefore should be conservative in most cases. Radiotherapy is indicated in patients with progressive visual deterioration. Surgery, when indicated, should be an en bloc excision.

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

NASA Astrophysics Data System (ADS)

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.

ICME-driven sheath regions deplete the outer radiation belt electrons

NASA Astrophysics Data System (ADS)

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

Parametric computational study of sheaths in multicomponent Ar/O2 plasma

NASA Astrophysics Data System (ADS)

Hromadka, J.; Ibehej, T.; Hrach, R.

2018-02-01

Our study is devoted to sheath structures emerging in Ar/O2 plasma. By means of two dimensional PIC/MCC computer model two configurations were investigated - sheath structure in the vicinity of a cylindrical Langmuir probe for two different biases and changes of the sheath structure when a cylindrical probe passes into a semi-planar probe. It was shown that O+ ions play important role in shielding out negative bias of a solid immersed in Ar/O2 plasma and edge effects of a semi-planar probe on its sheath structure were evaluated.

On the large-scale structure of the tail current as measured by THEMIS

NASA Astrophysics Data System (ADS)

Kalegaev, V. V.; Alexeev, I. I.; Nazarkov, I. S.; Angelopoulos, V.; Runov, A.

2014-11-01

The magnetic field structure and the spatial characteristics of the large-scale currents in the magnetospheric tail were studied during quiet and moderately disturbed geomagnetic conditions in 2009. The magnetic field of the currents other than the tail current was calculated in terms of a paraboloid model of the Earth’s magnetosphere, A2000, and was subtracted from measurements. It was found on the base of obtained tail current magnetic field radial distribution that the inner edge of the tail current sheet is located in the night side magnetosphere, at distances of about 10 RE and of about 7 RE during quiet and disturbed periods respectively. During the disturbance of February 14, 2009 (Dstmin ∼ -35 nT), the Bx and the Bz component of the tail current magnetic field near its inner edge were about 60 nT, and -60 nT that means that strong cross-tail current have been developed. The tail current parameters at different time moments during February 14, 2009 have been estimated. Solar wind conditions during this event were consistent with those during moderate magnetic storms with minimum Dst of about -100 nT. However, the magnetospheric current systems (magnetopause and cross-tail currents) were located at larger geocentric distances than typical during the 2009 extremely quiet epoch and did not provide the expected Dst magnitude. Very small disturbance on the Earth’s surface was detected consistent with an “inflated” magnetosphere.

Structural Aberrations in T-Even Bacteriophage V. Effects of Canavanine on the Maturation and Utilization of Specific Gene Products

PubMed Central

Bolin, Rex W.; Cummings, Donald J.

1974-01-01

Previous results have shown that when a T-even bacteriophage-infected cell was exposed to l-canavanine followed by an exposure to l-arginine, a monster phage particle, termed a lollipop, was formed. l-Canavanine was necessary for the induction event but l-arginine was required for the maturation of the particle. We now describe the effects of canavanine on the maturation of certain T4 proteins and their role in the induction of lollipops. The cleavage reactions of the head proteins P22, P23, P24, and IPIII are prevented by l-canavanine as shown by the accumulation of the precursor proteins and the failure of the cleaved products to appear. l-Canavanine also prevents the appearance of P12 (tailplate protein) and P20 (head protein) indicating that these proteins may undergo a proteolytic cleavage during normal assembly. The formation of P10 (tailplate protein) and P18 (tail sheath protein) is also affected by l-canavanine. The data suggest that P23 in conjunction with P20 plays a major role in the determination of the length of the phage head. Images PMID:4833614

Rectus sheath hematoma of the abdomen. Case report.

PubMed

Villena-Tovar, José Francisco

2010-01-01

Rectus sheath hematoma in the vast number of cases is due to an inferior epigastric artery tear occasionally due to trauma (not considered serious) or alterations in coagulation or use of anticoagulant therapy. It is an unlikely and difficult to diagnose pathology. We present the case of a 61-year-old female patient. The patient presented in emergency service with sudden abdominal pain caused by coughing as a result of an upper respiratory tract infection. The culmination was a spontaneous rectus sheath hematoma. Rectus sheath hematoma is a diagnosis to consider in a previously asymptomatic patient who presents with clinical features of acute pain and appearance of increase of volume in the abdominal wall involving the rectus muscles.

Novel everting urologic access sheath: decreased axial forces during insertion.

PubMed

Rubenstein, Jonathan N; Garcia, Maurice; Camargo, Affonso H L A; Joel, Andrew B; Stoller, Marshall L

2005-12-01

Advancement of urologic instruments through the genitourinary tract is associated with significant axial forces that likely contribute to patient discomfort, even after injection of a local anesthetic, and may lead to mucosal trauma, postprocedural dysuria and hematuria, and increased susceptibility to infection and strictures. Placing an everting urethral sheath prior to instrumentation may decrease these problems. Two 7-cm-long, 5-mm diameter urethral luminal models were created, one with and one without an artificial stricture. We measured the forces generated during advancement of a novel everting access sheath (Cystoglide; Percutaneous Systems, Mountain View, CA) through the models in comparison with a representative cystoscope and a urologic dilator simulating a traditional access sheath. The mean force generated during advancement of the everting sheath was significantly less than that of both the representative cystoscope (P<0.01) and the traditional access sheath (P<0.01). This held true for the urethral models both with and without an artificial stricture (P<0.01) and with and without lubrication (P<0.01). This novel introduction sheath markedly decreased the axial forces applied to an artificial urethral luminal wall. It is possible that the clinical use of this technology will decrease the discomfort and potential complications associated with lower urinary-tract endoscopy.

Physics-based parametrization of the surface impedance for radio frequency sheaths

DOE PAGES

Myra, J. R.

2017-07-07

The properties of sheaths near conducting surfaces are studied for the case where both magnetized plasma and intense radio frequency (rf) waves coexist. The work is motivated primarily by the need to understand, predict and control ion cyclotron range of frequency (ICRF) interactions with tokamak scrape-off layer plasmas, and is expected to be useful in modeling rf sheath interactions in global ICRF codes. Here, employing a previously developed model for oblique angle magnetized rf sheaths [J. R. Myra and D. A. D’Ippolito, Phys. Plasmas 22, 062507 (2015)], an investigation of the four-dimensional parameter space governing these sheath is carried out.more » By combining numerical and analytical results, a parametrization of the surface impedance and voltage rectification for rf sheaths in the entire four-dimensional space is obtained.« less

Physics-based parametrization of the surface impedance for radio frequency sheaths

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

Myra, J. R.

The properties of sheaths near conducting surfaces are studied for the case where both magnetized plasma and intense radio frequency (rf) waves coexist. The work is motivated primarily by the need to understand, predict and control ion cyclotron range of frequency (ICRF) interactions with tokamak scrape-off layer plasmas, and is expected to be useful in modeling rf sheath interactions in global ICRF codes. Here, employing a previously developed model for oblique angle magnetized rf sheaths [J. R. Myra and D. A. D’Ippolito, Phys. Plasmas 22, 062507 (2015)], an investigation of the four-dimensional parameter space governing these sheath is carried out.more » By combining numerical and analytical results, a parametrization of the surface impedance and voltage rectification for rf sheaths in the entire four-dimensional space is obtained.« less

Sperm fibrous sheath proteins: a potential new class of target antigens for use in human therapeutic cancer vaccines

PubMed Central

Chiriva-Internati, Maurizio; Cobos, Everardo; Da Silva, Diane M.

2008-01-01

Cancer vaccines have been demonstrated to be a promising strategy for treating human neoplastic disease, but one of the limitations of these vaccines remains the paucity of target antigens to which to direct an effective immune response. We hypothesize that sperm fibrous sheath proteins may be a new class of useful antigens for developing successful cancer vaccines. This hypothesis is supported by the expression of two sperm fibrous sheath proteins, called sperm protein 17 and calcium-binding tyrosine-phosphorylation regulated protein, in tumors of unrelated histological origin and their capability to induce T cell-based immune responses. PMID:18433090

Paucity of CD4+CCR5+ T cells is a typical feature of natural SIV hosts

PubMed Central

Pandrea, Ivona; Apetrei, Cristian; Gordon, Shari; Barbercheck, Joseph; Dufour, Jason; Bohm, Rudolf; Sumpter, Beth; Roques, Pierre; Marx, Preston A.; Hirsch, Vanessa M.; Kaur, Amitinder; Lackner, Andrew A.; Veazey, Ronald S.; Silvestri, Guido

2007-01-01

In contrast to lentiviral infections of humans and macaques, simian immunodeficiency virus (SIV) infection of natural hosts is nonpathogenic despite high levels of viral replication. However, the mechanisms underlying this absence of disease are unknown. Here we report that natural hosts for SIV infection express remarkably low levels of CCR5 on CD4+ T cells isolated from blood, lymph nodes, and mucosal tissues. Given that this immunologic feature is found in 5 different species of natural SIV hosts (sooty mangabeys, African green monkeys, mandrills, sun-tailed monkeys, and chimpanzees) but is absent in 5 nonnatural/recent hosts (humans, rhesus, pigtail, cynomolgus macaques, and baboons), it may represent a key feature of the coevolution between the virus and its natural hosts that led to a nonpathogenic infection. Beneficial effects of low CCR5 expression on CD4+ T cells may include the reduction of target cells for viral replication and a decreased homing of activated CD4+ T cells to inflamed tissue. PMID:17003371

SATELLITE PLASMA SHEATH ANOMALIES,

DTIC Science & Technology

Contents: Experimental Studies of the Kraus Effect Plasma Sheath and Screening around a Rapidly Moving Body Plasma Compression EEffects Produced...Kraus Effect Interaction of West Ford Needles with Earth’s Magnetosphere The Generation of Electromagnetic Waves in the Wake of a Satellite

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

PubMed

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.

Novel everting urologic access sheath: potential advantages of decreased cellular advancement.

PubMed

Camargo, Affonso H L A; Rubenstein, Jonathan N; Sozen, Sinan; Ershoff, Brent D; Stoller, Marshall L

2006-02-01

Axial forces are imposed on the urothelium during advancement of instruments across the urinary tract, potentially transferring cellular debris, bacteria, or urothelial carcinoma from one anatomic location to another. A prototype access sheath (Cystoglide; Percutaneous Systems, Mountain View, CA) was created that everts and radially dilates but does not provide axial forces during deployment that can be used in a variety of anatomic systems. We created a urinary-tract model to evaluate the in-vitro advancement of cells to compare this technology with using instruments alone. Blocks of sterile agar were created with 17F tracts of three lengths (2.7, 5.5, and 11 cm) with 5 mL of Luria-Bertani broth/ampicillin solution in a well at the end. The tips of a Cystoglide sheath and a traditional urologic instrument of the same diameter were dipped into a suspension of ampicillin-resistant Escherichia coli and advanced through the tracts. After a 10-second exposure, 4 mL of broth was collected and cultured. Bacterial growth was compared by measuring the optical density (OD) of the broth at multiple time points. The mean overall OD of the broth was significantly lower (P < 0.001) in the novel-sheath cultures than with a traditional instrument for all advancements at all tract lengths. The Cystoglide sheath significantly reduces the advancement of cells within an artificial urinary tract compared with a non-everting instrument. Clinical studies are needed to assess the utility of this technology in vivo.

Electron cyclotron maser instability in the solar corona - The role of superthermal tails

NASA Technical Reports Server (NTRS)

Vlahos, L.; Sharma, R. R.

1985-01-01

The effect of a superthermal component of electrons on the loss-cone-driven electron cyclotron maser instability is analyzed. It is found that for a superthermal tail with temperature about 10 KeV, the first harmonic (X- and O-mode) is suppressed for n(t)/n(r) of about 1 (n/t/ and n/r/ are the densities of superthermal tail and loss-cone electrons) and the second harmonic (X- and O-modes) is suppressed for n(t)/n(r) less than about 0.1. A qualitative discussion on the formation of superthermal tails is presented and it is suggested that superthermal tails play an important role on the observed or available power, at microwave frequencies, from the electron cyclotron maser instability in the solar corona.

Structural Ensemble of CD4 Cytoplasmic Tail (402-419) Reveals a Nearly Flat Free-Energy Landscape with Local α-Helical Order in Aqueous Solution.

PubMed

Ahalawat, Navjeet; Arora, Simran; Murarka, Rajesh K

2015-08-27

The human cluster determinant 4 (CD4), expressed primarily on the surface of T helper cells, serves as a coreceptor in T-cell receptor recognition of MHC II antigen complexes. Besides its cellular functions, CD4 serves as a primary receptor of human immunodeficiency virus (HIV) type 1. The cytoplasmic tail of CD4 (residues 402-419) is known to be involved in direct interaction with the HIV-1 proteins Vpu and Nef. These two viral accessory proteins (Vpu and Nef) downregulate CD4 in HIV-1 infected cells by multiple strategies and make the body susceptible to all forms of infections. In this work, we carried out extensive replica exchange molecular dynamics simulations in explicit water with three popular protein force fields Amber ff99SB, Amber ff99SB*-ILDN, and CHARMM36 to characterize the equilibrium conformational ensemble of CD4-tail (402-419) and further validated the simulated ensembles with known NMR data. We found that ff99SB*-ILDN gives a better description of the structural ensemble of this peptide compared with ff99SB and CHARMM36. The peptide adopts multiple distinct conformations with varying degree of residual secondary structures. In particular, we observed 28, 7, and 5% average α-helical, β-strand, and 3(10)-helix content, respectively, for ff99SB*-ILDN. The peptide chain shows the tendency of helix formation in a cooperative manner, seeding at residues 407-410, and subsequently extending toward both ends of the chain. Furthermore, we constructed Markov state model (MSM) from large-scale molecular dynamics simulations to study the dynamics of transitions between different metastable states explored by this peptide. The mean first passage times computed from MSM indicate rapid interconversion of these states, and the time scales of transitions range from several nanoseconds to hundreds of microseconds. Our results show good agreement with experimental data and could help to understand the key molecular mechanisms of T-cell activation and HIV

Impact of loop-tail ureteral stents on ureteral stent-related symptoms immediately after ureteroscopic lithotripsy: Comparison with pigtail ureteral stents

PubMed Central

Inoue, Takaaki; Muguruma, Kouei; Murota, Takashi; Kinoshita, Hidefumi; Matsuda, Tadashi

2017-01-01

Purpose To evaluate urination-related quality of life (QoL) in patients with an indwelling ureteral stent immediately after ureteroscopic lithotripsy (URSL) for upper urinary calculi. We compared the effects of loop-tail and pigtail ureteral stents on urination-related QoL. Materials and Methods Of 135 patients who underwent URSL between May 2014 and March 2015 at our hospital, we retrospectively analyzed the records of 70 patients (42 men, 28 women; median age, 63 years) in whom the stent tail was positioned inside the bladder without crossing the midline and who completed the core lower urinary tract symptoms score (CLSS) questionnaire pre- and postoperatively. Results There were significant differences in incomplete emptying (p=0.048) and bladder pain (p=0.041) between patients with loop-tail versus pigtail ureteral stents after URSL. In the multivariate analysis, stent type had a stronger association with incomplete emptying (p=0.022) and bladder pain (p=0.018) than age, sex, body mass index, stent side, operation time, diameter of ureteral access sheath, and stent type. Conclusions Patients with loop-tail ureteral stents had better urination-related QoL in the immediate post-URSL stage than patients with pigtail stents. PMID:29124244

VARIATION OF SPECTRAL AND TIMING PROPERTIES IN THE EXTENDED BURST TAILS FROM THE MAGNETAR 4U 0142+61

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

Chakraborty, Manoneeta; Göğüş, Ersin; Muş, Sinem Şaşmaz

2016-03-10

Extended emission episodes with an intensity above the preburst level are observed following magnetar bursts from a number of soft gamma repeaters and anomalous X-ray pulsars (AXPs). Such extended tail emissions were observed following two events detected from AXP 4U 0142+61. We investigated in detail the evolution of spectral and temporal properties during these two tail segments using Rossi X-ray Timing Explorer/Proportional Counter Array observations, and report distinct variations in the spectral and temporal behavior throughout the tails. In particular, in both cases we observed a sudden enhancement of the pulsation amplitude in conjunction with bursts and a smooth declinemore » of X-ray emission (cooling) during the tail. We suggest that an inefficiently radiating trapped fireball formed during the burst, which can heat up the stellar surface, is able to explain the tail properties and its energetics. We also present the episodic detection of absorption and emission features during tails. One possible mechanism that has been proposed to give rise to such spectral lines is the proton/ion cyclotron resonance process, which has been suggested as offering a valuable tool in probing the complex magnetic field of magnetars.« less

Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

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

Grin, A.; Lstiburek, J.

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 weremore » 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.« less

Kinetic model for the collisionless sheath of a collisional plasma

DOE PAGES

Tang, Xian-Zhu; Guo, Zehua

2016-08-04

Collisional plasmas typically have mean-free-path still much greater than the Debye length, so the sheath is mostly collisionless. Once the plasma density, temperature, and flow are specified at the sheath entrance, the profile variation of electron and ion density, temperature, flow speed, and conductive heat fluxes inside the sheath is set by collisionless dynamics, and can be predicted by an analytical kinetic model distribution. Finally, these predictions are contrasted in this paper with direct kinetic simulations, showing good agreement.

Velocity autocorrelation function in supercooled liquids: Long-time tails and anomalous shear-wave propagation.

PubMed

Peng, H L; Schober, H R; Voigtmann, Th

2016-12-01

Molecular dynamic simulations are performed to reveal the long-time behavior of the velocity autocorrelation function (VAF) by utilizing the finite-size effect in a Lennard-Jones binary mixture. Whereas in normal liquids the classical positive t^{-3/2} long-time tail is observed, we find in supercooled liquids a negative tail. It is strongly influenced by the transfer of the transverse current wave across the period boundary. The t^{-5/2} decay of the negative long-time tail is confirmed in the spectrum of VAF. Modeling the long-time transverse current within a generalized Maxwell model, we reproduce the negative long-time tail of the VAF, but with a slower algebraic t^{-2} decay.

A finite element procedure for radio-frequency sheath–plasma interactions based on a sheath impedance model

DOE PAGES

Kohno, H.; Myra, J. R.

2017-07-24

A finite element code that solves self-consistent radio-frequency (RF) sheath-plasma interaction problems is improved by incorporating a generalized sheath boundary condition in the macroscopic solution scheme. This sheath boundary condition makes use of a complex sheath impedance including both the sheath capacitance and resistance, which enables evaluation of not only the RF voltage across the sheath but also the power dissipation in the sheath. The newly developed finite element procedure is applied to cases where the background magnetic field is perpendicular to the sheath surface in one- and two-dimensional domains filled by uniform low- and high-density plasmas. The numerical resultsmore » are compared with those obtained by employing the previous capacitive sheath model at a typical frequency for ion cyclotron heating used in fusion experiments. It is shown that for sheaths on the order of 100 V in a high-density plasma, localized RF power deposition can reach a level which causes material damage. It is also shown that the sheath-plasma wave resonances predicted by the capacitive sheath model do not occur when parameters are such that the generalized sheath impedance model substantially modifies the capacitive character of the sheath. Here, possible explanations for the difference in the maximum RF sheath voltage depending on the plasma density are also discussed.« less

A finite element procedure for radio-frequency sheath–plasma interactions based on a sheath impedance model

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

Kohno, H.; Myra, J. R.

A finite element code that solves self-consistent radio-frequency (RF) sheath-plasma interaction problems is improved by incorporating a generalized sheath boundary condition in the macroscopic solution scheme. This sheath boundary condition makes use of a complex sheath impedance including both the sheath capacitance and resistance, which enables evaluation of not only the RF voltage across the sheath but also the power dissipation in the sheath. The newly developed finite element procedure is applied to cases where the background magnetic field is perpendicular to the sheath surface in one- and two-dimensional domains filled by uniform low- and high-density plasmas. The numerical resultsmore » are compared with those obtained by employing the previous capacitive sheath model at a typical frequency for ion cyclotron heating used in fusion experiments. It is shown that for sheaths on the order of 100 V in a high-density plasma, localized RF power deposition can reach a level which causes material damage. It is also shown that the sheath-plasma wave resonances predicted by the capacitive sheath model do not occur when parameters are such that the generalized sheath impedance model substantially modifies the capacitive character of the sheath. Here, possible explanations for the difference in the maximum RF sheath voltage depending on the plasma density are also discussed.« less

Development of a core sheath process for production of oxide fibers

NASA Technical Reports Server (NTRS)

Freske, S.

1972-01-01

Improvements were sought in an oxide fiber of a core sheath configuration intended for structural applications at 2000 F (1093 C). Discontinuities in the core were eliminated by using core materials other than pure alumina, and continuous core sheath fibers were produced. In the case of some core materials, the continuous sections were sufficiently long for applications in short fiber composites. Creep at 2000 F (1093 C) was found to be due, in most cases, to breaks in the core, allowing the glass sheath to creep. Evidence was obtained indicating that a closer match between the thermal expansion coefficient of the sheath and the core would greatly improve the strength.

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

PubMed

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.

Photovoltaic sheathing element with a flexible connector assembly

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

Langmaid, Joseph A; Keenihan, James R; Mills, Michael E

2016-07-12

The present invention is premised upon an assembly including at least a photovoltaic sheathing element capable of being affixed on a building structure, the sheathing element including at least: a photovoltaic cell assembly, a body portion attached to one or more portions of the photovoltaic cell assembly; at least a first and a second connector assembly disposed on opposing sides of the sheathing element and capable of directly or indirectly electrically connecting the photovoltaic cell assembly to at least two adjoining devices that are affixed to the building structure and wherein at least one of the connector assemblies includes amore » flexible portion; one or more connector pockets disposed in the body portion the pockets capable of receiving at least a portion of the connector assembly.« less

Optic Nerve Sheath Mechanics in VIIP Syndrome

NASA Technical Reports Server (NTRS)

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

The Other End of the Spear: The Tooth-to-Tail Ratio (T3R) in Modern Military Operations

DTIC Science & Technology

2007-01-01

units. Such a vehicle gave infantry much more of the fi repower and survivability inherent in heavy (mechanized infantry and armored) units while...The Other End of the Spear: The Tooth- to-Tail Ratio (T3R) in Modern Military Operations John J. McGrath The Long War Series Occasional Paper 23...collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources

Bedside Optic Nerve Sheath Diameter Assessment in the Identification of Increased Intracranial Pressure in Suspected Idiopathic Intracranial Hypertension.

PubMed

Irazuzta, Jose E; Brown, Martha E; Akhtar, Javed

2016-01-01

We determined whether the bedside assessment of the optic nerve sheath diameter could identify elevated intracranial pressure in individuals with suspected idiopathic intracranial hypertension. This was a single-center, prospective, rater-blinded study performed in a freestanding pediatric teaching hospital. Patients aged 12 to 18 years scheduled for an elective lumbar puncture with the suspicion of idiopathic intracranial hypertension were eligible to participate. Optic nerve sheath diameter was measured via ultrasonography before performing a sedated lumbar puncture for measuring cerebrospinal fluid opening pressure. Abnormal measurements were predefined as optic nerve sheath diameter ≥4.5 mm and a cerebrospinal fluid opening pressure greater than 20 cmH2O. Thirteen patients participated in the study, 10 of whom had elevated intracranial pressure. Optic nerve sheath diameter was able to predict or rule out elevated intracranial pressure in all patients. Noninvasive assessment of the optic nerve sheath diameter could help to identify patients with elevated intracranial pressure when idiopathic intracranial hypertension is suspected. Copyright © 2016 Elsevier Inc. All rights reserved.

The cytosolic tail of the Golgi apyrase Ynd1 mediates E4orf4-induced toxicity in Saccharomyces cerevisiae.

PubMed

Mittelman, Karin; Ziv, Keren; Maoz, Tsofnat; Kleinberger, Tamar

2010-11-22

The adenovirus E4 open reading frame 4 (E4orf4) protein contributes to regulation of the progression of virus infection. When expressed individually, E4orf4 was shown to induce non-classical transformed cell-specific apoptosis in mammalian cells. At least some of the mechanisms underlying E4orf4-induced toxicity are conserved from yeast to mammals, including the requirement for an interaction of E4orf4 with protein phosphatase 2A (PP2A). A genetic screen in yeast revealed that the Golgi apyrase Ynd1 associates with E4orf4 and contributes to E4orf4-induced toxicity, independently of Ynd1 apyrase activity. Ynd1 and PP2A were shown to contribute additively to E4orf4-induced toxicity in yeast, and to interact genetically and physically. A mammalian orthologue of Ynd1 was shown to bind E4orf4 in mammalian cells, confirming the evolutionary conservation of this interaction. Here, we use mutation analysis to identify the cytosolic tail of Ynd1 as the protein domain required for mediation of the E4orf4 toxic signal and for the interaction with E4orf4. We also show that E4orf4 associates with cellular membranes in yeast and is localized at their cytoplasmic face. However, E4orf4 is membrane-associated even in the absence of Ynd1, suggesting that additional membrane proteins may mediate E4orf4 localization. Based on our results and on a previous report describing a collection of Ynd1 protein partners, we propose that the Ynd1 cytoplasmic tail acts as a scaffold, interacting with a multi-protein complex, whose targeting by E4orf4 leads to cell death.

Using dust as probes to determine sheath extent and structure

NASA Astrophysics Data System (ADS)

Douglass, Angela; Land, V.; Qiao, K.; Matthews, L.; Hyde, T.

2016-08-01

Two in situ experimental methods are presented in which dust particles are used to determine the extent of the sheath and gain information about the time-averaged electric force profile within a radio frequency (RF) plasma sheath. These methods are advantageous because they are not only simple and quick to carry out, but they also can be performed using standard dusty plasma experimental equipment. In the first method, dust particles are tracked as they fall through the plasma towards the lower electrode. These trajectories are then used to determine the electric force on the particle as a function of height as well as the extent of the sheath. In the second method, dust particle levitation height is measured across a wide range of RF voltages. Similarities were observed between the two experiments, but in order to understand the underlying physics behind these observations, the same conditions were replicated using a self-consistent fluid model. Through comparison of the fluid model and experimental results, it is shown that the particles exhibiting a levitation height that is independent of RF voltage indicate the sheath edge - the boundary between the quasineutral bulk plasma and the sheath. Therefore, both of these simple and inexpensive, yet effective, methods can be applied across a wide range of experimental parameters in any ground-based RF plasma chamber to gain useful information regarding the sheath, which is needed for interpretation of dusty plasma experiments.

Sustained Benefit Lasting One Year from T4 Instead of T3-T4 Sympathectomy for Isolated Axillary Hyperhidrosis

PubMed Central

Munia, Marco Antonio S.; Wolosker, Nelson; Kaufmann, Paulo; de Campos, José Ribas Milanes; Puech-Leão, Pedro

2008-01-01

INTRODUCTION Level T4 video-assisted thoracoscopic sympathectomy proved superior to T3-T4 treatment for controlling axillary hyperhidrosis at the initial and six-month follow-ups of these patients. OBJECTIVE To compare the results of two levels of sympathectomy (T3-T4 vs. T4) for treating axillary sudoresis over one year of follow-up. METHODS Sixty-four patients with axillary hyperhidrosis were randomized to denervation of T3-T4 or T4 alone and followed prospectively. All patients were examined preoperatively and were followed postoperatively for one year. Axillary hyperhidrosis treatment was evaluated, along with the presence, location, and severity of compensatory hyperhidrosis and self-reported quality of life. RESULTS According to patient reports after one year, all cases of axillary hyperhidrosis were successfully treated by surgery. There were no instances of treatment failure. After six months, compensatory hyperhidrosis was present in 27 patients of the T3-T4 group (87.1%) and in 16 patients of the T4 group (48.5%). After one year, all T3-T4 patients experienced some degree of compensatory hyperhidrosis, compared to only 14 patients in the T4 group (42.4%). In addition, compensatory hyperhidrosis was less severe in the T4 patients (p < 0.01). Quality of life was poor before surgery, and it improved in both groups at six months and one year of follow-up (p = 0.002). There were no cases of mortality, no significant postoperative complications, and no need for conversion to thoracotomy in either group. CONCLUSION Both techniques were effective for treating axillary hyperhidrosis, but the T4 group showed milder compensatory hyperhidrosis and greater patient satisfaction at the one-year follow-up. PMID:19060999

Elongation growth of the leaf sheath base of Avena sativa seedlings: regulation by hormones and sucrose

NASA Technical Reports Server (NTRS)

Brock, T. G.; Kaufman, P. B.

1991-01-01

The leaf sheath base of the seedling of Avena sativa was characterized for growth response to hormones and sucrose. Six day old plants, raised under a 10:14 hr light:dark cycle, were excised at the coleoptilar node and 1 cm above the node for treatment. The growth of the leaf sheath base was promoted by gibberellic acid (GA3) and this response was dose dependent. The lag to response initiation was approximately 4 hr. Growth with or without GA3 (10 micromoles) was transient, diminishing appreciably after 48 hr. The addition of 10 mM sucrose greatly prolonged growth; the effect of GA3 and sucrose was additive. Neither indole-3-acetic acid (IAA) nor the cytokinin N6-benzyladenine (BA), alone or in combination, promoted the growth of leaf sheath bases. However, both significantly inhibited the action of GA3. The inhibitory effect of IAA was dose dependent and was not affected by the addition of BA or sucrose. These results indicate that the growth of leaf sheath bases of Avena sativa is promoted specifically by gibberellin, that this action depends on the availability of carbohydrates from outside of the leaf sheath base, and that the promotional effect of GA3 can be modified by either auxins or cytokinins.

A Semianalytical Ion Current Model for Radio Frequency Driven Collisionless Sheaths

NASA Technical Reports Server (NTRS)

Bose, Deepak; Govindan, T. R.; Meyyappan, M.; Arnold, Jim (Technical Monitor)

2001-01-01

We propose a semianalytical ion dynamics model for a collisionless radio frequency biased sheath. The model uses bulk plasma conditions and electrode boundary condition to predict ion impact energy distribution and electrical properties of the sheath. The proposed model accounts for ion inertia and ion current modulation at bias frequencies that are of the same order of magnitude as the ion plasma frequency. A relaxation equation for ion current oscillations is derived which is coupled with a damped potential equation in order to model ion inertia effects. We find that inclusion of ion current modulation in the sheath model shows marked improvements in the predictions of sheath electrical properties and ion energy distribution function.

The colloidal thyroxine (T4) ring as a novel biomarker of perchlorate exposure in the African clawed frog Xenopus laevis

USGS Publications Warehouse

Hu, F.; Sharma, Bibek; Mukhi, S.; Patino, R.; Carr, J.A.

2006-01-01

The purpose of this study was to determine if changes in colloidal thyroxine (T4) immunoreactivity can be used as a biomarker of perchlorate exposure in amphibian thyroid tissue. Larval African clawed frogs (Xenopus laevis) were exposed to 0, 1, 8, 93, and 1131 ??g perchlorate/l for 38 and 69 days to cover the normal period of larval development and metamorphosis. The results of this study confirmed the presence of an immunoreactive colloidal T4 ring in thyroid follicles of X. laevis and demonstrated that the intensity of this ring is reduced in a concentration-dependent manner by perchlorate exposure. The smallest effective concentration of perchlorate capable of significantly reducing colloidal T4 ring intensity was 8 ??g perchlorate/l. The intensity of the immunoreactive colloidal T4 ring is a more sensitive biomarker of perchlorate exposure than changes in hind limb length, forelimb emergence, tail resorption, thyrocyte hypertrophy, or colloid depletion. We conclude that the colloidal T4 ring can be used as a sensitive biomarker of perchlorate-induced thyroid disruption in amphibians. ?? Copyright 2006 Oxford University Press.

A STRUCTURAL ANALYSIS OF THE MYELIN SHEATH IN THE CENTRAL NERVOUS SYSTEM

PubMed Central

Hirano, Asao; Dembitzer, Herbert M.

1967-01-01

The cerebral white matter of rats subjected to a variety of noxious experimental conditions was examined in the electron microscope. Several unusual configurations of the myelin sheath are identified in addition to the usual configuration. These variations include the presence of (a) formed organelles within the inner and outer loops, (b) isolated islands of cytoplasm in unfused portions of the major dense lines, (c) apparently unconnected cell processes between the sheath and the axon, and (d) concentric, double myelin sheaths. A generalized model of the myelin sheath based on a hypothetical unrolling of the sheath is described. It consists of a shovel-shaped myelin sheet surrounded by a continuous thickened rim of cytoplasm. Most of the unusual myelin configurations are explained as simple variations on this basic theme. With the help of this model, an explanation of the formation of the myelin sheath is offered. This explanation involves the concept that myelin formation can occur at all cytoplasmic areas adjacent to the myelin proper and that adjacent myelin lamellae can move in relation to each other. PMID:6035645

On the upper bound in the Bohm sheath criterion

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

Kotelnikov, I. A., E-mail: I.A.Kotelnikov@inp.nsk.su; Skovorodin, D. I., E-mail: D.I.Skovorodin@inp.nsk.su

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 ionmore » 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.« less

Rectus sheath haematoma: a rare masquerader for abdominal pain.

PubMed

Changal, Khalid Hamid; Saleem, Saad; Ghous, Ghulam

2017-04-13

Rectus sheath haematoma is a rare cause of abdominal pain. It can be easily confused for other causes of acute abdomen and may even lead to unnecessary laparotomies. Our patient has the rectus sheath haematoma because of violent coughing and on presentation had no obvious clinical sign pointing to the same. Diagnosis was made by a CT scan of the abdomen, and patient was treated conservatively. Rectus sheath haematomas are usually present on the posterior aspect of the rectus muscles and thus may not be clinically appreciable. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Model and particle-in-cell simulation of ion energy distribution in collisionless sheath

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

Zhou, Zhuwen, E-mail: zzwwdxy@gznc.edu.cn; Key Laboratory of Photoelectron Materials Design and Simulation in Guizhou Province, Guiyang 550018; Scientific Research Innovation Team in Plasma and Functional Thin Film Materials in Guizhou Province, Guiyang 550018

2015-06-15

In this paper, we propose a self-consistent theoretical model, which is described by the ion energy distributions (IEDs) in collisionless sheaths, and the analytical results for different combined dc/radio frequency (rf) capacitive coupled plasma discharge cases, including sheath voltage errors analysis, are compared with the results of numerical simulations using a one-dimensional plane-parallel particle-in-cell (PIC) simulation. The IEDs in collisionless sheaths are performed on combination of dc/rf voltage sources electrodes discharge using argon as the process gas. The incident ions on the grounded electrode are separated, according to their different radio frequencies, and dc voltages on a separated electrode, themore » IEDs, and widths of energy in sheath and the plasma sheath thickness are discussed. The IEDs, the IED widths, and sheath voltages by the theoretical model are investigated and show good agreement with PIC simulations.« less

Redistribution of elements between wastes and organic-bearing material in the dispersion train of gold-bearing sulfide tailings: Part I. Geochemistry and mineralogy.

PubMed

Saryg-Ool, B Yu; Myagkaya, I N; Kirichenko, I S; Gustaytis, M A; Shuvaeva, O V; Zhmodik, S M; Lazareva, E V

2017-03-01

Migration and redistribution of elements during prolonged interaction of cyanide wastes with the underlying natural organic-bearing material have been studied in two ~40cm deep cores that sample primary ores and their weathering profile (wastes I and II, respectively) in the dispersion train of gold-bearing sulfide tailings in Siberia. Analytical results of SR-XRF, whole-rock XRF, AAS, CHNS, and SEM measurements of core samples show high K, Sr, Ti, and Fe enrichments and correlation of P 2 O 5 and Mn with LOI and C org . Organic material interlayered or mixed with the wastes accumulates Cu, Zn, Se, Cd, Ag, Au, and Hg. The peat that contacts wastes II bears up to 3wt.% Zn, 1000g/t Se, 100g/t Cd, and 8000g/t Hg. New phases of Zn and Hg sulfides and Hg selenides occur as abundant sheaths over bacterial cells suggesting microbial mediation in sorption of elements. Organic-bearing material in the cores contains 10-30g/t Au in 2-5cm thick intervals, both within and outside the intervals rich in sulfides and selenides. Most of gold is invisible but reaches 345g/t and forms 50nm to 1.5μm Au 0 particles in a thin 2-3cm interval of organic remnants mixed with wastes I. Vertical and lateral infiltration of AMD waters in peat and oxidative dissolution of wastes within the dispersion train of the Ursk tailings lead to redistribution of elements and their accumulation by combined physical (material's permeability, direction AMD), chemical (complexing, sorption by organic matter and Fe(III) hydroxides) and biochemical (metabolism of sulfate-reducing bacteria) processes. The accumulated elements form secondary sulfates, and Hg and Zn selenides. The results provide insights into accumulation of elements in the early history of coal and black shale deposits and have implications for remediation of polluted areas and for secondary enrichment technologies. Copyright © 2017 Elsevier B.V. All rights reserved.

Diagnostic and management of spontaneous rectus sheath hematoma.

PubMed

Smithson, Alex; Ruiz, Jessica; Perello, Rafael; Valverde, Marta; Ramos, Javier; Garzo, Luïsa

2013-09-01

Spontaneous rectus sheath hematoma is an uncommon and often misdiagnosed cause of abdominal pain. The aim of this study is to describe our experience in their management. Retrospective analysis of the characteristics and outcomes of the spontaneous rectus sheath hematomas diagnosed over the last 12years was conducted. 24 patients were included (66% women; mean age: 74years; range: 54-87). All cases presented predisposing factors mainly anticoagulant therapy in 21 (87.5%) patients, hypertension in 19 (79.1%) and abdominal surgery in 12 (50%) cases. Eighteen (75%) referred triggering factors like coughing being the most common one, present in 17 (70.8%) patients. The main clinical findings were abdominal pain in 21 (87.5%) cases and the existence of an abdominal mass in 20 (83.3%). The diagnosis was confirmed by abdominal ultrasonography and/or computerized tomography in 23 (95.8%) patients. Nineteen cases (79.1%) responded to conservative management while 5 (20.8%) required interventional treatment, which consisted in an arteriography with selective embolization of the epigastric arteries in all cases. Four (80%) of the patients needing interventional treatment were receiving low molecular weight heparin. Nine (37.5%) patients developed hypovolemic shock and 1 (4%) died. Spontaneous rectus sheath hematomas should be considered in the differential diagnosis of abdominal pain, particularly in elderly women under anticoagulant therapy with onset of symptoms after a bout of cough. Most cases respond to conservative management, although those related to low molecular weight heparin might require interventional treatment; arteriography with selective embolization of the epigastric arteries is the first therapeutic option. Copyright © 2013 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

A comparison of plasma levobupivacaine concentrations following transversus abdominis plane block and rectus sheath block.

PubMed

Yasumura, R; Kobayashi, Y; Ochiai, R

2016-05-01

Levobupivacaine is commonly used as the local anaesthetic of choice in peripheral nerve blocks, but its pharmacokinetics have not been fully investigated. We compared the changes in plasma concentrations of levobupivacaine following transversus abdominis plane block and rectus sheath block. Fifty woman undergoing laparoscopy were randomly allocated to receive either a transversus abdominis plane block or an rectus sheath block. In both groups, 2.5 mg.kg(-1) levobupivacaine was administered, and blood samples were obtained 15 min, 30 min, 60 min and 120 min after injection. The mean maximum plasma concentration (Cmax) and mean time to reach Cmax (Tmax) as determined by non-linear regression analysis were 1.05 μg.ml(-1) and 32.4 min in the transversus abdominis plane group and 0.95 μg.ml(-1) and 60.9 min in the rectus sheath group, respectively. The plasma concentration of levobupivacaine peaked earlier in the transversus abdominis plane group than in the rectus sheath group and the maximum plasma concentration depended on the dose administered but not the procedure. © 2016 The Association of Anaesthetists of Great Britain and Ireland.

Effect of phase assemblage of precursor on the fabrication process and properties of Bi2223 tape sheathed with Ag-alloy

NASA Astrophysics Data System (ADS)

Nakamura, Y.; Shioiri, T.; Kurihara, C.; Machida, T.; Inada, R.; Oota, A.

2008-09-01

The use of alloy sheath is effective to increase the strength of Ag-sheathed Bi2223 tapes. However, the Jc value of alloy sheathed tapes was not high enough since the undesired reaction to form impurity phases and the change in formation rate of Bi2223 were disturbed by the microstructure of the filaments . In this study, the effect of 2223 contents in precursor on the formation and property of Bi2223 tapes sheathed with Ag-Mg alloy was investigated. The conversion rate of Bi2223 from Bi2212 was increased by the addition of Bi2223 phase in precursor but the conversion rate in Ag-Mg alloy sheathed tapes was slower than that in the Ag-Cu alloy sheathed tapes. This reduction of conversion speed of Bi2223 may be attributed to the decrease in the growth rate of Bi2223 crystals in Ag-Mg alloy sheath. Since the tapes with small Bi2223 crystals after first sintering showed many outgrowths after final sintering, the formation of outgrowth would be caused in the case of small crystal size. The Jc value of 2.2 × 10 4 A/cm 2 was achieved in the samples using the precursor with 10 wt.% 2223. The high Jc value can be achieved by the proper control of precursor condition including the contents of Bi2223 and corresponding heat treatment pattern in Ag-Mg alloy sheathed tapes.

Effect of electron reflection on magnetized plasma sheath in an oblique magnetic field

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

Wang, Ting-Ting; Ma, J. X., E-mail: jxma@ustc.edu.cn; Wei, Zi-An

Magnetized plasma sheaths in an oblique magnetic field were extensively investigated by conventionally assuming Boltzmann relation for electron density. This article presents the study of the magnetized sheath without using the Boltzmann relation but by considering the electron reflection along the magnetic field lines caused by the negative sheath potential. A generalized Bohm criterion is analytically derived, and sheath profiles are numerically obtained, which are compared with the results of the conventional model. The results show that the ion Mach number at the sheath edge normal to the wall has a strong dependence on the wall potential, which differs significantlymore » from the conventional model in which the Mach number is independent of the wall potential. The floating wall potential is lower in the present model than that in the conventional model. Furthermore, the sheath profiles are appreciably narrower in the present model when the wall bias is low, but approach the result of the conventional model when the wall bias is high. The sheath thickness decreases with the increase of ion-to-electron temperature ratio and magnetic field strength but has a complex relationship with the angle of the magnetic field.« less

Coronal mass ejections and their sheath regions in interplanetary space

NASA Astrophysics Data System (ADS)

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.

Ion and electron sheath characteristics in a low density and low temperature plasma

NASA Astrophysics Data System (ADS)

Borgohain, Binita; Bailung, H.

2017-11-01

Ion and electron sheath characteristics in a low electron temperature (Te ˜ 0.25-0.40 eV) and density (ne ˜ 106-107 cm-3) plasma are described. The plasma is produced in the experimental volume through diffusion from a hot cathode discharge plasma source by using a magnetic filter. The electron energy distribution function in the experimental plasma volume is measured to be a narrow Maxwellian distribution indicating the absence of primary and energetic electrons which are decoupled in the source side by the cusp magnetic field near the filter. An emissive probe is used to measure the sheath potential profiles in front of a metal plate biased negative and positive with respect to the plasma potential. For a positive plate bias, the electron density decreases considerably and the electron sheath expands with a longer presheath region compared to the ion sheath. The sheath potential structures are found to follow the Debye sheath model.

Sheath effects observed on a 10 meter high voltage panel in simulated low earth orbit plasma

NASA Technical Reports Server (NTRS)

Mccox, J. E.; Konradi, A.

1979-01-01

A large (1m x 10m) flat surface of conductive material was biased to high voltage (+ or - 3000 V) to simulate the behavior of a large solar array in low earth orbit. The model array was operated in a plasma environment of 1,000 to 1,000,000/cu cm, with sufficient free space around it for the resulting plasma sheaths to develop unimpeded for 5-10 meters into the surrounding plasma. Measurements of the resulting sheath thickness were obtained. The observed thickness varied approximately as V to the 3/4 power and N to the 1/2 power. This effect appears to limit total current leakage from the test array until sheath dimensions exceed about 1 meter. Total leakage current was also measured with the array.

Crystallization of the carboxy-terminal region of the bacteriophage T4 proximal long tail fibre protein gp34

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

Granell, Meritxell; Namura, Mikiyoshi; Alvira, Sara

2014-06-19

The crystallization of three C-terminal fragments of the bacteriophage T4 protein gp34 is reported. Diffraction data have been obtained for three native crystal forms and two selenomethionine derivatives, one of which contained high-quality anomalous signal.

Oil sands thickened froth treatment tailings exhibit acid rock drainage potential during evaporative drying.

PubMed

Kuznetsov, Petr; Kuznetsova, Alsu; Foght, Julia M; Siddique, Tariq

2015-02-01

Bitumen extraction from oil sands ores after surface mining produces different tailings waste streams: 'froth treatment tailings' are enriched in pyrite relative to other streams. Tailings treatment can include addition of organic polymers to produce thickened tailings (TT). TT may be further de-watered by deposition into geotechnical cells for evaporative drying to increase shear strength prior to reclamation. To examine the acid rock drainage (ARD) potential of TT, we performed predictive analyses and laboratory experiments on material from field trials of two types of thickened froth treatment tailings (TT1 and TT2). Acid-base accounting (ABA) of initial samples showed that both TT1 and TT2 initially had net acid-producing potential, with ABA values of -141 and -230 t CaCO₃ equiv. 1000 t(-1) of TT, respectively. In long-term kinetic experiments, duplicate ~2-kg samples of TT were incubated in shallow trays and intermittently irrigated under air flow for 459 days to simulate evaporative field drying. Leachates collected from both TT samples initially had pH~6.8 that began decreasing after ~50 days (TT2) or ~250 days (TT1), stabilizing at pH~2. Correspondingly, the redox potential of leachates increased from 100-200 mV to 500-580 mV and electrical conductivity increased from 2-5 dS m(-1) to 26 dS m(-1), indicating dissolution of minerals during ARD. The rapid onset and prolonged ARD observed with TT2 is attributed to its greater pyrite (13.4%) and lower carbonate (1.4%) contents versus the slower onset of ARD in TT1 (initially 6.0% pyrite and 2.5% carbonates). 16S rRNA gene pyrosequencing analysis revealed rapid shift in microbial community when conditions became strongly acidic (pH~2) favoring the enrichment of Acidithiobacillus and Sulfobacillus bacteria in TT. This is the first report showing ARD potential of TT and the results have significant implications for effective management of pyrite-enriched oil sands tailings streams/deposits. Copyright © 2014

Discontinuous model with semi analytical sheath interface for radio frequency plasma

NASA Astrophysics Data System (ADS)

Miyashita, Masaru

2016-09-01

Sumitomo Heavy Industries, Ltd. provide many products utilizing plasma. In this study, we focus on the Radio Frequency (RF) plasma source by interior antenna. The plasma source is expected to be high density and low metal contamination. However, the sputtering the antenna cover by high energy ion from sheath voltage still have been problematic. We have developed the new model which can calculate sheath voltage wave form in the RF plasma source for realistic calculation time. This model is discontinuous that electronic fluid equation in plasma connect to usual passion equation in antenna cover and chamber with semi analytical sheath interface. We estimate the sputtering distribution based on calculated sheath voltage waveform by this model, sputtering yield and ion energy distribution function (IEDF) model. The estimated sputtering distribution reproduce the tendency of experimental results.

Determination of primary energy in nucleus-nucleus collisions and the high P(sub)T tail of alpha-particles

NASA Technical Reports Server (NTRS)

Freier, P. S.; Atwater, T. W.

1985-01-01

A determination of primary energy is required in order to study the energy dependence of meson multiplicity in A-A collisions in cosmic rays. Various procedures which estimate the energy of a primary nucleus from its interaction were investigated. An average of two methods were used, one using the pions and wounded protons and the other using spectator protons and alpha particles. The high P sub T tail observed for Z = 2 fragments requires a modification of the latter method.

Rice Sheath Rot: An Emerging Ubiquitous Destructive Disease Complex

PubMed Central

Bigirimana, Vincent de P.; Hua, Gia K. H.; Nyamangyoku, Obedi I.; Höfte, Monica

2015-01-01

Around one century ago, a rice disease characterized mainly by rotting of sheaths was reported in Taiwan. The causal agent was identified as Acrocylindrium oryzae, later known as Sarocladium oryzae. Since then it has become clear that various other organisms can cause similar disease symptoms, including Fusarium sp. and fluorescent pseudomonads. These organisms have in common that they produce a range of phytotoxins that induce necrosis in plants. The same agents also cause grain discoloration, chaffiness, and sterility and are all seed-transmitted. Rice sheath rot disease symptoms are found in all rice-growing areas of the world. The disease is now getting momentum and is considered as an important emerging rice production threat. The disease can lead to variable yield losses, which can be as high as 85%. This review aims at improving our understanding of the disease etiology of rice sheath rot and mainly deals with the three most reported rice sheath rot pathogens: S. oryzae, the Fusarium fujikuroi complex, and Pseudomonas fuscovaginae. Causal agents, pathogenicity determinants, interactions among the various pathogens, epidemiology, geographical distribution, and control options will be discussed. PMID:26697031

Saber-sheath trachea as a marker of severe airflow obstruction in chronic obstructive pulmonary disease.

PubMed

Ciccarese, Federica; Poerio, Antonio; Stagni, Silvia; Attinà, Domenico; Fasano, Luca; Carbonara, Paolo; Bacchi Reggiani, Maria Letizia; Zompatori, Maurizio

2014-02-01

Saber-sheath trachea is a specific radiographic parameter for chronic obstructive pulmonary disease (COPD), which consists of marked coronal narrowing associated with sagittal widening (tracheal index <2/3-0.67). The aim of this study was to investigate the correlation between saber-sheath trachea and clinical-radiological findings in a group of patients with COPD of varying severity. We evaluated the chest radiographs of 71 patients with COPD distributed as follows: GOLD class I, 8/71 (11.3 %); class II, 34/71 (47.9 %); class III, 16/71(22.5 %); class IV, 13/71 (18.3 %). In 52/71 (73.2 %) patients we also evaluated chest computed tomography (CT) scans. We analyzed the prevalence of saber-sheath trachea and its correlation with the Tiffenau index, GOLD stage and radiological signs of COPD. Moreover, we evaluated the sensitivity, specificity and accuracy of chest radiography as compared to CT taken as the gold standard, and the correlation between the radiographic and CT tracheal index. Saber-sheath trachea was found in 18/71 (25.4 %) patients, with a greater prevalence in patients with lower Tiffenau Index (p = 0.02), GOLD stages III-IV and visual severity score 3 (severe) on chest CT. Saber-sheath trachea was not found to be related to other radiological signs of COPD. The sensitivity, specificity and accuracy values of radiography were 72.2, 97.0 and 88.5 %, with perfect concordance between the radiographic and CT tracheal index (p < 0.00001). Saber-sheath trachea is linked to the functional severity of airway obstruction, but not to other radiological signs of COPD. Thus, evaluation of the trachea at chest radiography is strongly recommended.

Continuum kinetic and multi-fluid simulations of classical sheaths

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

Cagas, P.; Hakim, A.; Juno, J.

The kinetic study of plasma sheaths is critical, among other things, to understand the deposition of heat on walls, the effect of sputtering, and contamination of the plasma with detrimental impurities. The plasma sheath also provides a boundary condition and can often have a significant global impact on the bulk plasma. In this paper, kinetic studies of classical sheaths are performed with the continuum kinetic code, Gkeyll, which directly solves the Vlasov-Maxwell equations. The code uses a novel version of the finite-element discontinuous Galerkin scheme that conserves energy in the continuous-time limit. The fields are computed using Maxwell equations. Ionizationmore » and scattering collisions are included; however, surface effects are neglected. The aim of this work is to introduce the continuum kinetic method and compare its results with those obtained from an already established finite-volume multi-fluid model also implemented in Gkeyll. Novel boundary conditions on the fluids allow the sheath to form without specifying wall fluxes, so the fluids and fields adjust self-consistently at the wall. Our work demonstrates that the kinetic and fluid results are in agreement for the momentum flux, showing that in certain regimes, a multifluid model can be a useful approximation for simulating the plasma boundary. There are differences in the electrostatic potential between the fluid and kinetic results. Further, the direct solutions of the distribution function presented here highlight the non-Maxwellian distribution of electrons in the sheath, emphasizing the need for a kinetic model. The densities, velocities, and the potential show a good agreement between the kinetic and fluid results. But, kinetic physics is highlighted through higher moments such as parallel and perpendicular temperatures which provide significant differences from the fluid results in which the temperature is assumed to be isotropic. Besides decompression cooling, the heat flux is shown to

Continuum kinetic and multi-fluid simulations of classical sheaths

DOE PAGES

Cagas, P.; Hakim, A.; Juno, J.; ...

2017-02-21

The kinetic study of plasma sheaths is critical, among other things, to understand the deposition of heat on walls, the effect of sputtering, and contamination of the plasma with detrimental impurities. The plasma sheath also provides a boundary condition and can often have a significant global impact on the bulk plasma. In this paper, kinetic studies of classical sheaths are performed with the continuum kinetic code, Gkeyll, which directly solves the Vlasov-Maxwell equations. The code uses a novel version of the finite-element discontinuous Galerkin scheme that conserves energy in the continuous-time limit. The fields are computed using Maxwell equations. Ionizationmore » and scattering collisions are included; however, surface effects are neglected. The aim of this work is to introduce the continuum kinetic method and compare its results with those obtained from an already established finite-volume multi-fluid model also implemented in Gkeyll. Novel boundary conditions on the fluids allow the sheath to form without specifying wall fluxes, so the fluids and fields adjust self-consistently at the wall. Our work demonstrates that the kinetic and fluid results are in agreement for the momentum flux, showing that in certain regimes, a multifluid model can be a useful approximation for simulating the plasma boundary. There are differences in the electrostatic potential between the fluid and kinetic results. Further, the direct solutions of the distribution function presented here highlight the non-Maxwellian distribution of electrons in the sheath, emphasizing the need for a kinetic model. The densities, velocities, and the potential show a good agreement between the kinetic and fluid results. But, kinetic physics is highlighted through higher moments such as parallel and perpendicular temperatures which provide significant differences from the fluid results in which the temperature is assumed to be isotropic. Besides decompression cooling, the heat flux is shown to

Chemical and ecotoxicity evaluation of tailings rehabilitated using Technosol

NASA Astrophysics Data System (ADS)

Arán, Diego; Santos, Erika S.; Abreu, Maria Manuela; Macías, Felipe

2017-04-01

The Fé mining area was the most important uranium deposit in Spain. In this deposit, the uranium mineralization contains sulfides. Consequently, tailings are a source of polymetallic contamination requiring their rehabilitation in order to decrease the dispersion of potentially hazardous elements (PHEs). The main objective of this work is to evaluate the efficiency of a Technosol application on the rehabilitation of these tailings at chemical and ecotoxicological level. In the field, a layer of 20 cm Technosol with andic and eutrophic characteristic was applied over the tailing (total area: 625 m2). After 20 months, composite samples of Technosol (TEC), recovered tailing (bottom of the Technosol, RT) and tailings without recuperation (T) were collected. These samples were characterized for pH, electric conductivity (EC), PHEs concentration in total fraction and available fraction extracted with rhizosphere-based method. Ecotoxicity bioassays were carried out with two species, Lollium perenne and Trifolium pratense following OECD Guidelines. Three bioassays were carried out: filter paper test and hydroponic test with leachates, and soil test. In leachates (extracted with DIN method) were determined pH, EC and same PHEs than in Technosol/Tailings. Visual aspects, germination, root and shoot elongation and dry biomass were evaluated. The substrate effect on growth of both species was evaluated in pot experiment (500 g Technosol/Tailings per pot, 70% of water-holding capacity) under greenhouse conditions after 69 days by dry shoot biomass. Materials from T had pH 4, EC: 1.2 mS/cm and high total concentrations of several PHEs (g/kg; Al: 46.2; As, Co and Pb: 0.02-0.03; Cu: 0.04; Fe: 63.2 Mn: 1.3; Ni and Zn: 0.1-0.2). However, PHEs concentrations in leachates and available fraction corresponded to <2.5% of total concentrations, except for Co, Mn and Ni where 7-18% of their total concentrations can be available to organisms. Leachates from RT showed a significant

TIDAL TAILS OF MINOR MERGERS. II. COMPARING STAR FORMATION IN THE TIDAL TAILS OF NGC 2782

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

Knierman, Karen A.; Scowen, Paul; Veach, Todd

2013-09-10

The peculiar spiral NGC 2782 is the result of a minor merger with a mass ratio {approx}4: 1 occurring {approx}200 Myr ago. This merger produced a molecular and H I-rich, optically bright eastern tail and an H I-rich, optically faint western tail. Non-detection of CO in the western tail by Braine et al. suggested that star formation had not yet begun. However, deep UBVR and H{alpha} narrowband images show evidence of recent star formation in the western tail, though it lacks massive star clusters and cluster complexes. Using Herschel PACS spectroscopy, we discover 158 {mu}m [C II] emission at themore » location of the three most luminous H{alpha} sources in the eastern tail, but not at the location of the even brighter H{alpha} source in the western tail. The western tail is found to have a normal star formation efficiency (SFE), but the eastern tail has a low SFE. The lack of CO and [C II] emission suggests that the western tail H II region may have a low carbon abundance and be undergoing its first star formation. The western tail is more efficient at forming stars, but lacks massive clusters. We propose that the low SFE in the eastern tail may be due to its formation as a splash region where gas heating is important even though it has sufficient molecular and neutral gas to make massive star clusters. The western tail, which has lower gas surface density and does not form high-mass star clusters, is a tidally formed region where gravitational compression likely enhances star formation.« less

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

PubMed

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.

The structure and development of the starch sheath in pea epicotyls

NASA Technical Reports Server (NTRS)

Sack, D. F.

1985-01-01

Graviperception in plant stems is thought to occur in endodermal cells differentiated as a starch sheath, but little is known about the ultrastructure of these cells in dicots. The structure of the pea starch sheath was studied with respect to gravity and to development in order to determine whether symplastic or apoplastic blockages exist and to describe any intracellular polarity. Amyloplasts increase in size towards the base of the epicotyl hook but are not consistently sedimented until the cells enter the zone exhibiting gravicurvature below the hook. The starch sheath cells are connected to each other and to cells of the cortex and the stele by plasmodesmata. A casparian strip exists in older endodermal cells but not at the stage that the endodermis is differentiated as a starch sheath. Amyloplasts were frequently observed in apparent contact with endoplasmic reticulum.

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Bacillus pumilus ES4: candidate plant growth-promoting bacterium to enhance establishment of plants in mine tailings

PubMed Central

de-Bashan, Luz E.; Hernandez, Juan-Pablo; Bashan, Yoav; Maier, Raina

2014-01-01

Three plant growth-promoting bacteria (PGPB; Bacillus pumilus ES4, B. pumilus RIZO1, and Azospirillum brasilense Cd) were tested for their ability to enhance plant growth and development of the native Sonoran Desert shrub quailbush (Atriplex lentiformis) and for their effect on the native bacterial community in moderately acidic, high-metal content (AHMT) and in neutral, low metal content natural tailings (NLMT) in controlled greenhouse experiments. Inoculation of quailbush with all three PGPB significantly enhanced plant growth parameters, such as germination, root length, dry weight of shoots and roots, and root/shoot ratio in both types of tailings. The effect of inoculation on the indigenous bacterial community by the most successful PGPB Bacillus pumilus ES4 was evaluated by denaturating gradient gel electrophoresis (PCR-DGGE) fingerprinting and root colonization was followed by specific fluorescent in situ hybridization (FISH). Inoculation with this strain significantly changed the bacterial community over a period of 60 days. FISH analysis showed that the preferred site of colonization was the root tips and root elongation area. This study shows that inoculation of native perennial plants with PGPB can be used for developing technologies for phytostabilizing mine tailings. PMID:25009362

Phylogenetic Diversity of T4-Type Phages in Sediments from the Subtropical Pearl River Estuary

PubMed Central

He, Maoqiu; Cai, Lanlan; Zhang, Chuanlun; Jiao, Nianzhi; Zhang, Rui

2017-01-01

Viruses are an abundant and active component of marine sediments and play a significant role in microbial ecology and biogeochemical cycling at local and global scales. To obtain a better understanding of the ecological characteristics of the viriobenthos, the abundance and morphology of viruses and the diversity and community structure of T4-type phages were systematically investigated in the surface sediments of the subtropical Pearl River Estuary (PRE). Viral abundances ranged from 4.49 × 108 to 11.7 × 108 viruses/g and prokaryotic abundances ranged from 2.63 × 108 to 9.55 × 108 cells/g, and both decreased from freshwater to saltwater. Diverse viral morphotypes, including tailed, spherical, filamentous, and rod-shaped viruses, were observed using transmission electron microscopy. Analysis of the major capsid gene (g23) indicated that the sediment T4-type phages were highly diverse and, similar to the trend in viral abundances, their diversity decreased as the salinity increased. Phylogenetic analysis suggested that most of the g23 operational taxonomic units were affiliated with marine, paddy soil, and lake groups. The T4-type phage communities in freshwater and saltwater sediments showed obvious differences, which were related to changes in the Pearl River discharge. The results of this study demonstrated both allochthonous and autochthonous sources of the viral community in the PRE sediments and the movement of certain T4-type viral groups between the freshwater and saline water biomes. PMID:28572798

Is there a role for small-diameter ureteral access sheaths? Impact on irrigant flow and intrapelvic pressures.

PubMed

Monga, Manoj; Bodie, Joshua; Ercole, Barbara

2004-09-01

To evaluate irrigant flows and intrapelvic pressures with small-diameter access sheaths. Ureteral access sheaths improve irrigant flow and decrease intrarenal pelvic pressures during flexible ureteroscopy. However, no comparisons of individual sheaths have been conducted. Previous studies have demonstrated more favorable results with the 12F sheath than with the 10F sheath. Ureteral access sheaths were tested ex vivo in porcine kidneys. An 18F angiocatheter was placed in the renal pelvis and connected to a Hewlett Packard Gauss Pressure transducer. Irrigant was maintained at 100 mm Hg pressure. Irrigant flow and intrapelvic pressures were measured with three flexible ureteroscopes at baseline and using each of four 10F sheaths, with the sheaths positioned in the middle ureter and the ureteroscopes positioned in the renal pelvis. The pressure at which irrigant efflux through the sheath occurred and the rate of irrigant efflux through the access sheath were measured. Intrapelvic pressures measured greater than 40 mm Hg, and irrigant flows remained at less than 15 mL/min when the Olympus URF-P3 and Storz 11274AAU flexible ureteroscopes were tested with all four sheaths. The intrapelvic pressures, irrigant inflow, and irrigant efflux with the Wolf 7325.172 (7.5F) flexible ureteroscope were optimized in combination with the Cook Peelaway 10F and Applied Access 10F sheaths. Small ureteral access sheaths should be used only with the Wolf 7325.172 flexible ureteroscope. The Cook Peelaway (10F) and Applied Access (10F) sheaths offered the greatest increase in irrigant flow and decrease in intrapelvic pressures.

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

PubMed

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.

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

PubMed Central

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

1992-01-01

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. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 7 Fig. 8 Fig. 9 PMID:1295858

Plaque-Like Pilar Sheath Acanthoma: Histopathologic and Immunohistochemical Study of 3 Unusual Cases.

PubMed

Jo-Velasco, Margarita; Corrales-Rodríguez, Araceli; Francés-Rodríguez, Laura; Alegría-Landa, Victoria; Eraña-Tomás, Itziar; Rütten, Arno; Requena, Luis

2018-02-01

Pilar sheath acanthoma is an uncommon, benign follicular neoplasm that frequently presents as a solitary lesion. This neoplasm usually appears on the skin around the upper lip of elderly patients. Histopathologically, the neoplasm usually shows a cystic configuration with epithelial lobules resembling to those of the outer root sheath of the hair follicle at the level of the isthmus emanating radially from the cyst wall. We present 3 peculiar cases of a pilar sheath acanthoma showing a plaque-like architecture because the lesions exhibited a horizontal configuration. To our knowledge, there are no previously reported examples of plaque-like pilar sheath acanthoma.

Optic Nerve Sheath Meningocele: A Case Report

PubMed Central

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

Automatic early warning of tail biting in pigs: 3D cameras can detect lowered tail posture before an outbreak

PubMed Central

Jack, Mhairi; Futro, Agnieszka; Talbot, Darren; Zhu, Qiming; Barclay, David; Baxter, Emma M.

2018-01-01

Tail biting is a major welfare and economic problem for indoor pig producers worldwide. Low tail posture is an early warning sign which could reduce tail biting unpredictability. Taking a precision livestock farming approach, we used Time-of-flight 3D cameras, processing data with machine vision algorithms, to automate the measurement of pig tail posture. Validation of the 3D algorithm found an accuracy of 73.9% at detecting low vs. not low tails (Sensitivity 88.4%, Specificity 66.8%). Twenty-three groups of 29 pigs per group were reared with intact (not docked) tails under typical commercial conditions over 8 batches. 15 groups had tail biting outbreaks, following which enrichment was added to pens and biters and/or victims were removed and treated. 3D data from outbreak groups showed the proportion of low tail detections increased pre-outbreak and declined post-outbreak. Pre-outbreak, the increase in low tails occurred at an increasing rate over time, and the proportion of low tails was higher one week pre-outbreak (-1) than 2 weeks pre-outbreak (-2). Within each batch, an outbreak and a non-outbreak control group were identified. Outbreak groups had more 3D low tail detections in weeks -1, +1 and +2 than their matched controls. Comparing 3D tail posture and tail injury scoring data, a greater proportion of low tails was associated with more injured pigs. Low tails might indicate more than just tail biting as tail posture varied between groups and over time and the proportion of low tails increased when pigs were moved to a new pen. Our findings demonstrate the potential for a 3D machine vision system to automate tail posture detection and provide early warning of tail biting on farm. PMID:29617403

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

NASA Astrophysics Data System (ADS)

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

Evolutionary sheath structure in magnetized collisionless plasma with electron inertia

NASA Astrophysics Data System (ADS)

Gohain, M.; Karmakar, P. K.

2017-09-01

A classical hydrodynamic model is methodologically formulated to see the equilibrium properties of a planar plasma sheath in two-component magnetized bounded plasma. It incorporates the weak but finite electron inertia instead of asymptotically inertialess electrons. The effects of the externally applied oblique (relative to the bulk plasma flow) magnetic field are judiciously accented. It is, for the sake of simplicity, assumed that the relevant physical parameters (plasma density, electrostatic potential, and flow velocity) vary only in a direction normal to the confining wall boundary. It is noticed for the first time that the derived Bohm condition for sheath formation is modified conjointly by the electron inertia, magnetic field, and field orientation. It is manifested that the electron inertia in the presence of plasma gyrokinetic effects slightly enhances the ion Mach threshold value (typically, M i0 ≥ 1.139) toward the sheath entrance. This flow supercriticality is in contrast with the heuristic formalism ( M i0 ≥ 1) for the zero-inertia electrons. A numerical illustrative scheme on the parametric sheath features on diverse nontrivial apposite arguments is constructed alongside ameliorative scope.

Apoptotic depletion of CD4+ T cells in idiopathic CD4+ T lymphocytopenia.

PubMed Central

Laurence, J; Mitra, D; Steiner, M; Lynch, D H; Siegal, F P; Staiano-Coico, L

1996-01-01

Progressive loss of CD4+ T lymphocytes, accompanied by opportunistic infections characteristic of the acquired immune deficiency syndrome, ahs been reported in the absence of any known etiology. The pathogenesis of this syndrome, a subset of idiopathic CD4+ T lymphocytopenia (ICL), is uncertain. We report that CD4+ T cells from seven of eight ICL patients underwent accelerated programmed cell death, a process facilitated by T cell receptor cross-linking. Apoptosis was associated with enhanced expression of Fas and Fas ligand in unstimulated cell populations, and partially inhibited by soluble anti-Fas mAb. In addition, apoptosis was suppressed by aurintricarboxylic acid, an inhibitor of calcium-dependent endonucleases and proteases, in cells from four of seven patients, The in vivo significance of these findings was supported by three factors: the absence of accelerated apoptosis in persons with stable, physiologic CD4 lymphopenia without clinical immune deficiency; detection of serum antihistone H2B autoantibodies, one consequence of DNA fragmentation, in some patients; and its selectivity, with apoptosis limited to the CD4 population in some, and occurring among CD8+ T cells predominantly in those individuals with marked depletion of both CD4+ T lymphocytes linked to clinical immune suppression have evidence for accelerated T cell apoptosis in vitro that may be pathophysiologic and amenable to therapy with apoptosis inhibitors. PMID:8609222

Continuum-kinetic approach to sheath simulations

NASA Astrophysics Data System (ADS)

Cagas, Petr; Hakim, Ammar; Srinivasan, Bhuvana

2016-10-01

Simulations of sheaths are performed using a novel continuum-kinetic model with collisions including ionization/recombination. A discontinuous Galerkin method is used to directly solve the Boltzmann-Poisson system to obtain a particle distribution function. Direct discretization of the distribution function has advantages of being noise-free compared to particle-in-cell methods. The distribution function, which is available at each node of the configuration space, can be readily used to calculate the collision integrals in order to get ionization and recombination operators. Analytical models are used to obtain the cross-sections as a function of energy. Results will be presented incorporating surface physics with a classical sheath in Hall thruster-relevant geometry. This work was sponsored by the Air Force Office of Scientific Research under Grant Number FA9550-15-1-0193.

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

NASA Technical Reports Server (NTRS)

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.

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

PubMed Central

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

The in-process control of PVC sheath of a double core cable

NASA Astrophysics Data System (ADS)

Galeeva, N. S.; Redko, V. V.; Redko, L. A.

2018-01-01

In this work the possibility of the sheath hermiticity testing by measuring of the cable capacity per unit length variation during spark testing is considered. The research object is 2×0.75 HO3VVH2-F cable. According to the physical modelling it is proved that such defect of sheath as pinhole through the whole thickness of sheath can be registered for the test length 10 cm with test voltage frequencies 1kHz and 10kHz.

Establishment of dermal sheath cell line from Cashmere goat and characterizing cytokeratin 13 as its novel biomarker.

PubMed

Zhu, Bing; Guo, Zhili; Jin, Muzi; Bai, Yujuan; Yang, Wenliang; Hui, Lihua

2018-05-01

To establish a dermal sheath cell line, a dermal papilla cell line and a outer root sheath cell line from Cashmere goat and clarify the similarities and differences among them. We established a dermal sheath cell line, a dermal papilla cell line and a outer root sheath cell line from the pelage skin hair follicles of Cashmere goat. The growth rate of dermal sheath cells was intermediate between that of dermal papilla cells and outer root sheath cells. Immunofluorescence experiments and reverse transcription-polymerase chain reaction analysis showed that at both the transcriptional and translational levels, the dermal sheath cells were alpha-smooth muscle actin (α-SMA) + /cytokeratin 13 + , while the dermal papilla cells were α-SMA + /cytokeratin 13 - and the outer root sheath cells were α-SMA - /cytokeratin 13 + . Patterns of cytokeratin 13 expression could distinguish the dermal sheath cells from the dermal papilla cells. These results suggest that cytokeratin 13 could serve as a novel biomarker for dermal sheath cells of Cashmere goat, and should prove useful for researchers investigating dermal stem cells or interaction of different types of cells during hair cycle.

A New Approach to Pathogen Containment in the Operating Room: Sheathing the Laryngoscope After Intubation.

PubMed

Birnbach, David J; Rosen, Lisa F; Fitzpatrick, Maureen; Carling, Philip; Arheart, Kristopher L; Munoz-Price, L Silvia

2015-11-01

Anesthesiologists may contribute to postoperative infections by means of the transmission of blood and pathogens to the patient and the environment in the operating room (OR). Our primary aims were to determine whether contamination of the IV hub, the anesthesia work area, and the patient could be reduced after induction of anesthesia by removing the risk associated with contaminants on the laryngoscope handle and blade. Therefore, we conducted a study in a simulated OR where some of the participants sheathed the laryngoscope handle and blade in a glove immediately after it was used to perform an endotracheal intubation. Forty-five anesthesiology residents (postgraduate year 2-4) were enrolled in a study consisting of identical simulation sessions. On entry to the simulated OR, the residents were asked to perform an anesthetic, including induction and endotracheal intubation timed to approximately 6 minutes. Of the 45 simulation sessions, 15 were with a control group conducted with the intubating resident wearing single gloves, 15 with the intubating resident using double gloves with the outer pair removed and discarded after verified intubation, and 15 wearing double gloves and sheathing the laryngoscope in one of the outer gloves after intubation. Before the start of the scenario, the lips and inside of the mouth of the mannequin were coated with a fluorescent marking gel. After each of the 45 simulations, an observer examined the OR using an ultraviolet light to determine the presence of fluorescence on 25 sites: 7 on the patient and 18 in the anesthesia environment. Of the 7 sites on the patient, ultraviolet light detected contamination on an average of 5.7 (95% confidence interval, 4.4-7.2) sites under the single-glove condition, 2.1 (1.5-3.1) sites with double gloves, and 0.4 (0.2-1.0) sites with double gloves with sheathing. All 3 conditions were significantly different from one another at P < 0.001. Of the 18 environmental sites, ultraviolet light detected

Community Structure of Filamentous, Sheath-Building Sulfur Bacteria, Thioploca spp., off the Coast of Chile.

PubMed

Schulz, H N; Jorgensen, B B; Fossing, H A; Ramsing, N B

1996-06-01

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 down into the sediment. The structure of the Thioploca communities off the Bay of Concepcion was investigated with 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(sup-2), was found at a depth of 90 m. The bacterial filaments within the sheaths contributed about 10% of this weight. The highest density of filaments was found within the uppermost 1 cm of the mat. On the basis of diameter classes, it was possible to distinguish populations containing only Thioploca spp. from mixed populations containing Beggiatoa spp. Three distinct size classes of Thioploca spp. were found, two of which have been described previously as Thioploca araucae and Thioploca chileae. Many Thioploca filaments did not possess a visible sheath, and about 20% of the sheaths contained more than one Thioploca species. The three-dimensional sheath structure showed that Thioploca filaments can move from the surface and deep into the sediment.

Med5(Nut1) and Med17(Srb4) Are Direct Targets of Mediator Histone H4 Tail Interactions

PubMed Central

Liu, Zhongle; Myers, Lawrence C.

2012-01-01

The Mediator complex transmits activation signals from DNA bound transcription factors to the core transcription machinery. In addition to its canonical role in transcriptional activation, recent studies have demonstrated that S. cerevisiae Mediator can interact directly with nucleosomes, and their histone tails. Mutations in Mediator subunits have shown that Mediator and certain chromatin structures mutually impact each other structurally and functionally in vivo. We have taken a UV photo cross-linking approach to further delineate the molecular basis of Mediator chromatin interactions and help determine whether the impact of certain Mediator mutants on chromatin is direct. Specifically, by using histone tail peptides substituted with an amino acid analog that is a UV activatible crosslinker, we have identified specific subunits within Mediator that participate in histone tail interactions. Using Mediator purified from mutant yeast strains we have evaluated the impact of these subunits on histone tail binding. This analysis has identified the Med5 subunit of Mediator as a target for histone tail interactions and suggests that the previously observed effect of med5 mutations on telomeric heterochromatin and silencing is direct. PMID:22693636

The Relation of Carbon Dioxide Compensation and Chlorenchymatous Vascular Bundle Sheaths in Leaves of Dicots

PubMed Central

Crookston, R. Kent; Moss, Dale N.

1970-01-01

Low CO2 compensation points have been found to be associated with several unusual characteristics related to photosynthesis. One such characteristic is a prominent, chlorenchymatous vascular bundle sheath in the leaves. It has been suggested that the presence of this sheath in dicotyledons can serve as a means of detecting low CO2-compensating species. We collected 88 dicotyledon species from 22 families reported to have chlorenchymatous sheaths. Of the 88, only three, Tribulus terrestris, L., Boerhaavia paniculata, L. C. Rich, and Trianthema portulacastrum L., had low CO2 compensation points. Cross sections of the leaves of the other species revealed that they did have chlorenchymatous vascular bundle sheaths. However, these sheath cells contained chloroplasts which were not specialized for starch formation as were the bundle sheath chloroplasts of the low CO2-compensating species. Images PMID:16657506

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

Code of Federal Regulations, 2010 CFR

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...

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

Code of Federal Regulations, 2012 CFR

2012-07-01

..., 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...

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

Code of Federal Regulations, 2014 CFR

2014-07-01

..., 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...

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

Code of Federal Regulations, 2011 CFR

2011-07-01

..., 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...

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

Code of Federal Regulations, 2013 CFR

2013-07-01

..., 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...

Near-tail reconnection as the cause of cometary tail disconnections

NASA Technical Reports Server (NTRS)

Russell, C. T.; Saunders, M. A.; Phillips, J. L.; Fedder, J. A.

1986-01-01

In a cometary tail disconnection event the plasma tail appears to separate from the coma and to accelerate away from it. As this occurs a new tail begins to form. It is proposed that these disconnections arise in a manner analogous to geomagnetic substorms, i.e., by the formation of a strongly reconnecting region in the near tail that forms a magnetic island in the coma and ejects the plasma tail by strengthening the magnetic 'slingshot' within the tail. This reconnection process may be triggered by several different processes, such as interplanetary shocks or variations in the Alfven Mach number.

Allelic analysis of sheath blight resistance with association mapping in rice

USDA-ARS?s Scientific Manuscript database

Sheath blight is one of the most devastating diseases world-wide in rice. For the first time, we adopted association mapping to identify quantitative trait loci for sheath blight resistance from the USDA rice mini-core collection. The phenotyping was conducted with a newly developed micro-chamber me...

Self-assembly behavior of tail-to-tail superstructure formed by mono-6-O-(4-carbamoylmethoxy-benzoyl)-β-cyclodextrin in solution and the solid state.

PubMed

Xu, Zhe; Chen, Xin; Liu, Jing; Yan, Dong-Qing; Diao, Chun-Hua; Guo, Min-Jie; Fan, Zhi

2014-07-01

A novel mono-modified β-cyclodextrin (β-CD) consisting of 4-carbamoylmethoxy-benzoyl unit at the primary side was synthesized and its self-assembly behavior was determined by X-ray crystallography and NMR spectroscopy. The crystal structure shows a 'Yin-Yang'-like packing mode, in which the modified β-CD exhibits a channel superstructure formed by a tail-to-tail dimer as the repeating motif with the substituted group embedded within the hydrophobic cavity of the facing β-CD. The geometry of the substituted group is determined by the inclusion of the cavity and is further stabilized by two intermolecular hydrogen bonds between the carbonyl O atom and phenyl group. Furthermore, NMR ROESY investigation indicates that the self-assembly behavior of the substituted group within the β-CD cavity is retained in aqueous solution, and the effective binding constant Ka was calculated to be 1330 M(-1) by means of (1)H NMR titration according to iterative determination. Copyright © 2014 Elsevier Ltd. All rights reserved.

Structural and experimental investigations of the functional anatomy and the turgor of the notochord in the larval tail of anuran tadpoles.

PubMed

Platz, Franz

2006-07-01

The premetamorphotic morphology and metamorphotic degeneration of the tail notochord of anuran tadpoles has been investigated. For this purpose the functional anatomy and origin of the notochord turgor was analysed in 10 species macroscopically and using light, transmission and scanning electron microscopic techniques. The notochord consists of the fibrous notochord sheath, which surrounds the notochord cells. Within the sheath these cells form a net-like unit. The inner cells are derived from the marginal notochord cells (chordoblasts). They are protected from mechanical overload by intracellular filaments and desmosomes. Due to their vacuoles, which are filled with a hyaline liquid, they have a constant volume but are deformable. Dissolved substances may pass from the vascularized fin to the notochord cells. The transport from marginal to inner cells occurs via cytopempsis and micropinocytosis. The morphological correlation of this process consists of multiple membrane invaginations and intracellular vesicles. Within the notochord cells a high turgor pressure has been observed. During metamorphosis the membrane vesiculation persists and the notochord cells degenerate. Due to the loss of turgor pressure the tight consistency of the notochord is lost. The collagen filaments and the elastic membrane of the notochord sheath dissolve. Notochord cells with their filaments, high turgor pressure and their central vacuole can function as a combined mechanical and physiological system, which is adaptable to the needs of pressure, compression, tensile and bending forces.

Evaluation of metal mobility from copper mine tailings in northern Chile.

PubMed

Lam, Elizabeth J; Gálvez, M E; Cánovas, M; Montofré, I L; Rivero, D; Faz, A

2016-06-01

This work shows the results obtained on a copper mine tailing in the Antofagasta Region, Chile. The tailing was classified as saline-sodic with high concentrations of metals, especially Cu and Fe, with pH 8.4. Our objectives were to (1) compare the physicochemical properties of the tailing with surrounding soils of the mine under study, and (2) evaluate the effect of two amendments (CaCO3 and compost) and their mixtures on Cu(2+), Mn, Fe, Zn, Mg(2+), and K(+) and Ca(2+), SO4 (2-), NO3 (-), and PO4 (3-) leaching. The data obtained were submitted to variance and covariance analysis. The results from the comparison between both substrates showed that in general, the tailing presented greater content of metals. Regarding tailing leaching, pH, electrical conductivity (EC), and concentration of the elements of interest were measured. The statistical analysis showed that Cu(2+) leaching and immobilization of Fe occurred to the greatest extent with compost. The EC decreased throughout the experiment with irrigation and increased upon treatment with compost. The major interactions found among the chemical parameters were (1) tailings without treatment, Cu(2+)/Fe and NO3 (-)/SO4 (2-); (2) tailings treated with CaCO3, Cu(2+)/K(+); (3) tailings treated with compost, NO3 (-)/SO4 (-2) and EC/Cu(2+); and (4) tailings treated with both amendments, EC/Fe and Cu(2+)/Fe. The ANOVA showed that the number of irrigations and the amendments statistically significantly affected the copper mobility and the organic amendment significantly influenced the iron mobility.

Ultrasound-guided rectus sheath block in children with umbilical hernia: Case series.

PubMed

Alsaeed, Abdul Hamid; Thallaj, Ahmed; Khalil, Nancy; Almutaq, Nada; Aljazaeri, Ayman

2013-10-01

Umbilical hernia repair, a common day-case surgery procedure in children, is associated with a significant postoperative pain. The most popular peripheral nerve blocks used in umbilical hernia repair are rectus sheath infiltration and caudal block. The rectus sheath block may offer improved pain relief following umbilical hernia repair with no undesired effects such as lower limb motor weakness or urinary retention seen with caudal block which might delay discharge from the hospital. Ultrasound guidance of peripheral nerve blocks has reduced the number of complications and improved the quality of blocks. The aim of this case series is to assess the post rectus sheath block pain relief in pediatric patients coming for umbilical surgery. Twenty two (22) children (age range: 1.5-8 years) scheduled for umbilical hernia repair were included in the study. Following the induction of general anesthesia, the ultrasonographic anatomy of the umbilical region was studied with a 5-16 MHz 50 mm linear probe. An ultrasound-guided posterior rectus sheath block of both rectus abdominis muscles (RMs) was performed (total of 44 punctures). An in-plain technique using Stimuplex A insulated facet tip needle 22G 50mm. Surgical conditions, intraoperative hemodynamic parameters, and postoperative analgesia by means of the modified CHEOPS scale were evaluated. ultrasonograghic visualization of the posterior sheath was possible in all patients. The ultrasound guided rectus sheath blockade provided sufficient analgesia in all children with no need for additional analgesia except for one patient who postoperatively required morphine 0.1 mg/kg intravenously. There were no complications. Ultrasound guidance enables performances of an effective rectus sheath block for umbilical hernia. Use of the Stimuplex A insulated facet tip needle 22G 50mm provides easy, less traumatic skin and rectus muscle penetration and satisfactory needle visualiza.

A Randomized Study of SheathLess vs Standard Guiding Catheters for Transradial Percutaneous Coronary Interventions.

PubMed

Noble, Stephane; Tessitore, Elena; Gencer, Baris; Righini, Marc; Robert-Ebadi, Helia; Roffi, Marco; Bonvini, Robert F

2016-12-01

The small diameter of radial arteries remains a major limitation of the transradial approach for percutaneous coronary intervention (PCI). Sheathless guiding catheters (GCs) might offer an advantage over standard GCs. Between 2011 and 2013, we randomized 233 transradial PCIs performed in men with ostial or bifurcation lesions and in all women between standard GC (Medtronic Launcher; Minneapolis, MN) and the SheathLess Eaucath GC (Asahi Intecc, Aichi, Japan). Successful PCI using the transradial approach was not different between the groups (P = 0.74), however the rate of successful transradial PCI with the designated GC (ie, without crossover to the opposing GC) was superior in the SheathLess group compared with the standard GC group (96.5% vs 89.9%; P = 0.047). Safety end point (ie, absence of PCI complication, radial artery occlusion, perforation, pseudoaneurysm, and Early Discharge after Transradial Stenting of Coronary Arteries [EASY] hematoma grade ≥ 2) did not differ between the groups (60.5% in both groups). Mean PCI duration (45.1 minutes vs 45.9 minutes), fluoroscopy (20.1 minutes and 19.9 minutes), and cannulation times (3.6 minutes vs 3.7 minutes), contrast media volume (196 mL vs 187 mL) and conversion to transfemoral approach (1.8% vs 0.8%) were not different between the groups. Patients' subjective assessment revealed less arm pain during navigation of the SheathLess GC (1.9 ± 1.9 vs 4.8 ± 3.6; P < 0.001). Operators graded arm crossability as easier with the SheathLess GC (8.7 ± 1.5 vs 5.1 ± 3.5; P < 0.001). In selected coronary lesions requiring large-bore catheters in men and in all lesions in women, the SheathLess GC was superior to the standard GC for successful transradial PCI with the designated GC. The SheathLess GC was also associated with easier arm navigation and less patient discomfort. Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Photovoltaic building sheathing element with anti-slide features

DOEpatents

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.

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

PubMed

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

NASA Astrophysics Data System (ADS)

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.

Plasma sheath effects on ion collection by a pinhole

NASA Technical Reports Server (NTRS)

Herr, Joel L.; Snyder, David B.

1993-01-01

This work presents tables to assist in the evaluation of pinhole collection effects on spacecraft. These tables summarize results of a computer model which tracks particle trajectories through a simplified electric field in the plasma sheath. A technique is proposed to account for plasma sheath effects in the application of these results and scaling rules are proposed to apply the calculations to specific situations. This model is compared to ion current measurements obtained by another worker, and the agreement is very good.

Structural and Functional Studies of gpX of Escherichia coli Phage P2 Reveal a Widespread Role for LysM Domains in the Baseplates of Contractile-Tailed Phages

PubMed Central

Fatehi Hassanabad, Mostafa; Chang, Tom; Pirani, Nawaz; Bona, Diane; Edwards, Aled M.

2013-01-01

A variety of bacterial pathogenicity determinants, including the type VI secretion system and the virulence cassettes from Photorhabdus and Serratia, share an evolutionary origin with contractile-tailed myophages. The well-characterized Escherichia coli phage P2 provides an excellent system for studies related to these systems, as its protein composition appears to represent the “minimal” myophage tail. In this study, we used nuclear magnetic resonance (NMR) spectroscopy to determine the solution structure of gpX, a 68-residue tail baseplate protein. Although the sequence and structure of gpX are similar to those of LysM domains, which are a large family associated with peptidoglycan binding, we did not detect a peptidoglycan-binding activity for gpX. However, bioinformatic analysis revealed that half of all myophages, including all that possess phage T4-like baseplates, encode a tail protein with a LysM-like domain, emphasizing a widespread role for this domain in baseplate function. While phage P2 gpX comprises only a single LysM domain, many myophages display LysM domain fusions with other tail proteins, such as the DNA circulation protein found in Mu-like phages and gp53 of T4-like phages. Electron microscopy of P2 phage particles with an incorporated gpX-maltose binding protein fusion revealed that gpX is located at the top of the baseplate, near the junction of the baseplate and tail tube. gpW, the orthologue of phage T4 gp25, was also found to localize to this region. A general colocalization of LysM-like domains and gpW homologues in diverse phages is supported by our bioinformatic analysis. PMID:24097944

Retrieval of a detached transseptal sheath tip from a right pulmonary artery branch following catheter ablation.

PubMed

Schricker, Amir A; Feld, Gregory K; Tsimikas, Sotirios

2015-11-15

Transseptal introducer sheaths are being used with increasing frequency for left-sided arrhythmia ablations and structural heart disease interventions. Sheath tip detachment and embolization is an uncommon but known complication, and several sheaths have been recalled due to such complications. We report a unique case of a fractured transseptal sheath tip that embolized to a branch of the right pulmonary artery in a patient who had undergone ablation of a left-sided atypical atrial flutter. During final removal of one of the two long 8.5-French SL1 transseptal sheaths used routinely as part of the ablation, the radiopaque tip of the sheath fractured and first embolized to the right atrium and subsequently to a secondary right pulmonary artery branch. Using techniques derived from percutaneous interventional approaches, including a multipurpose catheter, coronary guidewire, and monorail angioplasty balloon, the sheath tip was successfully wired through its inner lumen, trapped from the inside with the balloon, and removed from the body via a large femoral vein sheath, without complications. The approach detailed in this case may guide future cases and circumvent urgent surgical intervention. © 2015 Wiley Periodicals, Inc.

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

NASA Astrophysics Data System (ADS)

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.

Structure-function analysis of the DNA translocating portal of the bacteriophage T4 packaging machine.

PubMed

Padilla-Sanchez, Victor; Gao, Song; Kim, Hyung Rae; Kihara, Daisuke; Sun, Lei; Rossmann, Michael G; Rao, Venigalla B

2014-03-06

Tailed bacteriophages and herpesviruses consist of a structurally well conserved dodecameric portal at a special 5-fold vertex of the capsid. The portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. Although the structures of portals from phages φ29, SPP1, and P22 have been determined, their mechanistic roles have not been well understood. Structural analysis of phage T4 portal (gp20) has been hampered because of its unusual interaction with the Escherichia coli inner membrane. Here, we predict atomic models for the T4 portal monomer and dodecamer, and we fit the dodecamer into the cryo-electron microscopy density of the phage portal vertex. The core structure, like that from other phages, is cone shaped with the wider end containing the "wing" and "crown" domains inside the phage head. A long "stem" encloses a central channel, and a narrow "stalk" protrudes outside the capsid. A biochemical approach was developed to analyze portal function by incorporating plasmid-expressed portal protein into phage heads and determining the effect of mutations on head assembly, DNA translocation, and virion production. We found that the protruding loops of the stalk domain are involved in assembling the DNA packaging motor. A loop that connects the stalk to the channel might be required for communication between the motor and the portal. The "tunnel" loops that project into the channel are essential for sealing the packaged head. These studies established that the portal is required throughout the DNA packaging process, with different domains participating at different stages of genome packaging. © 2013.

Structure-Function Analysis of the DNA Translocating Portal of the Bacteriophage T4 Packaging Machine

PubMed Central

Padilla-Sanchez, Victor; Gao, Song; Kim, Hyung Rae; Kihara, Daisuke; Sun, Lei; Rossmann, Michael G.; Rao, Venigalla B.

2013-01-01

Tailed bacteriophages and herpesviruses consist of a structurally well conserved dodecameric portal at a special five-fold vertex of the capsid. The portal plays critical roles in head assembly, genome packaging, neck/tail attachment, and genome ejection. Although the structures of portals from phages φ29, SPP1 and P22 have been determined, their mechanistic roles have not been well understood. Structural analysis of phage T4 portal (gp20) has been hampered because of its unusual interaction with the E. coli inner membrane. Here, we predict atomic models for the T4 portal monomer and dodecamer, and fit the dodecamer into the cryoEM density of the phage portal vertex. The core structure, like that from other phages, is cone-shaped with the wider end containing the “wing” and “crown” domains inside the phage head. A long “stem” encloses a central channel, and a narrow “stalk” protrudes outside the capsid. A biochemical approach was developed to analyze portal function by incorporating plasmid-expressed portal protein into phage heads and determining the effect of mutations on head assembly, DNA translocation, and virion production. We found that the protruding loops of the stalk domain are involved in assembling the DNA packaging motor. A loop that connects the stalk to the channel might be required for communication between the motor and portal. The “tunnel” loops that project into the channel are essential for sealing the packaged head. These studies established that the portal is required throughout the DNA packaging process, with different domains participating at different stages of genome packaging. PMID:24126213

Liquid gallium columns sheathed with carbon: Bulk synthesis and manipulation.

PubMed

Zhan, Jinhua; Bando, Yoshio; Hu, Junqing; Golberg, Dmitri; Nakanishi, Haruyuki

2005-06-16

It is impossible to fabricate isolated gallium nanomaterials due to the low melting point of Ga (29.8 degrees C) and its high reactivity. We report the bulk synthesis of uniform liquid Ga columns encapsulated into carbon nanotubes through high-temperature chemical reaction between Ga and CH4. The diameter of filled Ga liquid columns is approximately 25 nm, and their length is up to several micrometers. The thickness of the carbon sheaths is approximately 6 nm. Simultaneous condensation of a Ga vapor and carbon clusters results in the generation of Ga-filled carbon nanotubes. A convergent 300 kV electron beam generated in a field emission high-resolution electron microscope is demonstrated to be a powerful tool for delicate manipulation of the liquid Ga nanocolumns: they can be gently joined, cut, and sealed within carbon nanotubes. The self-organization of a carbon sheath during the electron-beam irradiation is discussed. The electron-beam irradiation may also become a decent tool for Ga-filled carbon nanotube thermometer calibration.

Pathologic changes in the cytokeratin pericanalicular sheath in experimental cholestasis and alcoholic fatty liver.

PubMed

Ohta, M; Marceau, N; French, S W

1988-07-01

The architectural framework of the pericanalicular sheath composed of cytokeratin intermediate filaments (IFs) was examined after phalloidin treatment, bile duct ligation, and alcoholic fatty liver in rats to assess the role of IFs in experimental cholestasis. Electron microscopy examination of whole mount unembedded extracted liver slices was employed to visualize the cytoskeleton. Immunofluorescence staining and immunoelectron microscopy of the sheath were also performed using monoclonal antibodies to rat hepatocyte cytokeratins CK49 and CK55. The thickness of the wall and the diameter of the lumens were measured. In the phalloidin-treated rats, the pericanalicular sheath was markedly dilated and thickened. Immunofluorescence staining showed that the CK49 and CK55 IFs were localized in the pericanalicular region, particularly in the pericentral area. Immunoelectron microscopy documented that the IFs at the thickened pericanalicular sheath consisted of both CK49 and CK55, which means that the thickening of the bile canaliculus was in part due to an increase of IFs and not just due to an increase in actin filaments. In the livers where the bile duct was ligated, the pericanalicular sheath was irregularly dilated and some parts of the sheath appeared thinned out or missing. The belt desmosome also appeared absent focally in the pericanalicular sheath. Immunofluorescence studies showed that the staining for CK49 and CK55 was reduced focally in the pericanalicular region. The CK55 antibody stained the cytoplasm of hepatocytes in the periportal area more intensely when compared with the controls. These results indicated that the pericanalicular sheath and the belt desmosome were focally disrupted in response to extrahepatic bile duct obstruction. In the ethanol-fed rats, the pericanalicular sheath was dilated, thickened and tortuous, and appeared focally flattened by large fat droplets. IFs in the cytoplasm were pushed to the cell periphery and were compressed against

Moisture Durability with Vapor-Permeable Insulating Sheathing

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

Lepage, R.; Lstiburek, J.

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 differentmore » climate zones. This report describes the research project, key research questions, and theprocedures utilized to analyse the problems.« less

Moisture Durability with Vapor-Permeable Insulating Sheathing

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

Lepage, R.; Lstiburek, J.

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 ofmore » different climate zones. This report describes the research project, key research questions, and the procedures utilized to analyse the problems.« less

Characteristic features of the magnetoresistance in the ferrimagnetic (Sr2FeMoO6-δ) - dielectric (SrMoO4) nanocomposite

NASA Astrophysics Data System (ADS)

Demyanov, S.; Kalanda, N.; Yarmolich, M.; Petrov, A.; Lee, S.-H.; Yu, S.-C.; Oh, S. K.; Kim, D.-H.

2018-05-01

Magnetic metal-oxide compounds with high values of magnetoresistance (MR) have attracted huge interest for spintronic applications, among which Sr2FeMoO6-δ (SFMO) has been relatively less known compared to the cobaltites and manganites, despite 100% electrons spin-polarization degree and a high Curie temperature. Here, stable fabrication and systematic analysis of nanocomposites based on SFMO with SrMoO4 dielectric sheaths are presented. SFMO-SrMoO4 nanocomposites were fabricated as follows: synthesis of the SFMO single-phase nanopowders by the modified citrate-gel technique; compaction under high pressure; thermal treatment for sheaths formation around grains. The nanocomposite is observed to exhibit a transitional behavior of conductivity from metallic, which is characteristic for the SFMO to semiconductor one in the temperature range 4 - 300K under magnetic fields up to 10T. A negative MR is observed due to the spin-polarized charge carriers tunneling through dielectric sheaths. MR value reaches 43% under 8T at 10κ. The dielectric sheaths thickness was determined to be about 10 nm by electric breakdown voltage value at current-voltage characteristics curves. The breakdown is found to be a reversible process determined by collisional ionization of dielectric atoms in strong electric field depending on knocked-out electrons from the SrMoO4. It was found that MR changes sign in electric breakdown region, revealing the giant magnetoresistive properties.

Complete Genome Sequence of the Broad-Host-Range Vibriophage KVP40: Comparative Genomics of a T4-Related Bacteriophage

PubMed Central

Miller, Eric S.; Heidelberg, John F.; Eisen, Jonathan A.; Nelson, William C.; Durkin, A. Scott; Ciecko, Ann; Feldblyum, Tamara V.; White, Owen; Paulsen, Ian T.; Nierman, William C.; Lee, Jong; Szczypinski, Bridget; Fraser, Claire M.

2003-01-01

The complete genome sequence of the T4-like, broad-host-range vibriophage KVP40 has been determined. The genome sequence is 244,835 bp, with an overall G+C content of 42.6%. It encodes 386 putative protein-encoding open reading frames (CDSs), 30 tRNAs, 33 T4-like late promoters, and 57 potential rho-independent terminators. Overall, 92.1% of the KVP40 genome is coding, with an average CDS size of 587 bp. While 65% of the CDSs were unique to KVP40 and had no known function, the genome sequence and organization show specific regions of extensive conservation with phage T4. At least 99 KVP40 CDSs have homologs in the T4 genome (Blast alignments of 45 to 68% amino acid similarity). The shared CDSs represent 36% of all T4 CDSs but only 26% of those from KVP40. There is extensive representation of the DNA replication, recombination, and repair enzymes as well as the viral capsid and tail structural genes. KVP40 lacks several T4 enzymes involved in host DNA degradation, appears not to synthesize the modified cytosine (hydroxymethyl glucose) present in T-even phages, and lacks group I introns. KVP40 likely utilizes the T4-type sigma-55 late transcription apparatus, but features of early- or middle-mode transcription were not identified. There are 26 CDSs that have no viral homolog, and many did not necessarily originate from Vibrio spp., suggesting an even broader host range for KVP40. From these latter CDSs, an NAD salvage pathway was inferred that appears to be unique among bacteriophages. Features of the KVP40 genome that distinguish it from T4 are presented, as well as those, such as the replication and virion gene clusters, that are substantially conserved. PMID:12923095

Differential positioning of C(4) mesophyll and bundle sheath chloroplasts: recovery of chloroplast positioning requires the actomyosin system.

PubMed

Kobayashi, Hiroaki; Yamada, Masahiro; Taniguchi, Mitsutaka; Kawasaki, Michio; Sugiyama, Tatsuo; Miyake, Hiroshi

2009-01-01

In C(4) plants, bundle sheath (BS) chloroplasts are arranged in the centripetal position or in the centrifugal position, although mesophyll (M) chloroplasts are evenly distributed along cell membranes. To examine the molecular mechanism for the intracellular disposition of these chloroplasts, we observed the distribution of actin filaments in BS and M cells of the C(4) plants finger millet (Eleusine coracana) and maize (Zea mays) using immunofluorescence. Fine actin filaments encircled chloroplasts in both cell types, and an actin network was observed adjacent to plasma membranes. The intracellular disposition of both chloroplasts in finger millet was disrupted by centrifugal force but recovered within 2 h in the dark. Actin filaments remained associated with chloroplasts during recovery. We also examined the effects of inhibitors on the rearrangement of chloroplasts. Inhibitors of actin polymerization, myosin-based activities and cytosolic protein synthesis blocked migration of chloroplasts. In contrast, a microtubule-depolymerizing drug had no effect. These results show that C(4) plants possess a mechanism for keeping chloroplasts in the home position which is dependent on the actomyosin system and cytosolic protein synthesis but not tubulin or light.

The Efficiency of Delone Coverings of the Canonical Tilings T}(*(A_4)) -> T^*(A4) and T}(*(D_6)) -> T^*(D6)

NASA Astrophysics Data System (ADS)

Papadopolos, Zorka; Kasner, Gerald

This chapter is devoted to the coverings of the two quasiperiodic canonical tilings T}(*(A_4)) -> T^*(A4) and T}(*(D_6)) equiv {cal T}(*(2F)) -> T^*(D6) T^*(2F), obtained by projection from the root lattices A4 and D6, respectively. In the first major part of this chapter, in Sect. 5.2, we shall introduce a Delone covering T}(*(A_4)}) -> C^sT^*(A4) of the 2-dimensional decagonal tiling T}(*(A_4)) -> T^*(A4). In the second major part of this chapter, Sect. 5.3, we summarize the results related to the Delone covering of the icosahedral tiling T}(*(D_6)) -> T^*(D6), T}(*(D_6)}) -> CT^*(D6) and determine the zero-, single-, and double- deckings and the resulting thickness of the covering. In the conclusions section, we give some suggestions as to how the definition of the Delone covering might be changed in order to reach some real (full) covering of the icosahedral tiling T}(*(D_6)) -> T^*(D6). In Section 5.2 the definition of the Delone covering is also changed in order to avoid an unnecessary large thickness of the covering.

Isolation of Mesophyll Cells and Bundle Sheath Cells from Digitaria sanguinalis (L.) Scop. Leaves and a Scanning Microscopy Study of the Internal Leaf Cell Morphology.

PubMed

Edwards, G E; Black, C C

1971-01-01

A technique is described for the separation of mesophyll and bundle sheath cells from Digitaria sanguinalis leaves and evidence for separation is given with light and scanning electron micrographs. Gentle grinding of fully differentiated leaves in a mortar releases mesophyll cells which are isolated on nylon nets by filtration. More extensive grinding of the remaining tissue yields bundle sheath strands which are isolated by filtration with stainless steel sieves and nylon nets. Further grinding of bundle sheath strands in a tissue homogenizer releases bundle sheath cells which are collected on nylon nets. Percentage of purity derived from cell counts and yield data on a chlorophyll basis are given.The internal leaf cell morphology is presented in scanning electron micrographs and compared with light micrographs of fully-differentiated D. sanguinalis leaves. In leaves of plants which possess the C(4)-dicarboxylic acid cycle of photosynthesis, the relationship of leaf morphology to photosynthesis in mesophyll and bundle sheath cells is considered, and the hypothesis is presented that as atmospheric CO(2) enters a leaf about 85% is fixed by the C(4)-dicarboxylic acid cycle in the mesophyll cells and 10 to 15% is fixed by the reductive pentose phosphate cycle in the bundle sheath cells.A technique also is given for the isolation of mesophyll cells from spinach leaves.

A computer-controlled apparatus for Seebeck inhomogeneity testing of sheathed thermocouples

NASA Technical Reports Server (NTRS)

Burkett, Cecil G., Jr.; Bauserman, Willard A., Jr.

1993-01-01

Mineral-insulated metal-sheathed (MIMS) thermocouple assemblies are used throughout industry and research facilities as a method of temperature measurement where requirements for either harsh environmental conditions exist, or where rigidity of the measurement probe is required. Seebeck inhomogeneity is the abnormal variation of the Seebeck coefficient from point to point in a material. It is not disclosed in conventional calibration. A standardized method of measuring thermoelectric inhomogeneity along the thermocouple probe length is not available. Therefore, calibration for sheathed probes normally does not include testing of probe inhomogeneity. The measurement accuracy would be severely impacted if significant inhomogeneity and a temperature gradient were present in the same region of the probe. A computer-controlled system for determining inhomogeneities was designed, fabricated, and tested. This system provides an accurate method for the identification of the location of inhomogeneity along the length of a sheathed thermocouple and for the quantification of the inhomogeneity. This paper will discuss the apparatus and procedure used to perform these tests and will present data showing tests performed on sheathed thermocouple probes.

Three-step Channel Conformational Changes Common to DNA Packaging Motors of Bacterial Viruses T3, T4, SPP1, and Phi29

PubMed Central

Wang, Shaoying; Ji, Zhouxiang; Yan, Erfu; Haque, Farzin; Guo, Peixuan

2016-01-01

The DNA packaging motor of dsDNA bacterial viruses contains a head-tail connector with a channel for genome to enter during assembly and to exit during host infection. The DNA packaging motor of bacterial virus phi29 was recently reported to use the “One-way Revolution” mechanism for DNA packaging. This raises a question of how dsDNA is ejected during infection if the channel acts as a one-way inward valve. Here we report a three step conformational change of the portal channel that is common among DNA translocation motors of bacterial viruses T3, T4, SPP1, and phi29. The channels of these motors exercise three discrete steps of gating, as revealed by electrophysiological assays. It is proposed that the three step channel conformational changes occur during DNA entry process, resulting in a structural transition in preparation of DNA movement in the reverse direction during ejection. PMID:27181501

Diagnostic Quality of Magnetic Resonance Imaging Interpretation for Peripheral Nerve Sheath Tumors: Can Malignancy Be Determined?

PubMed

Karsy, Michael; Guan, Jian; Ravindra, Vijay M; Stilwill, Sarah; Mahan, Mark A

2016-11-01

Background Optimal management of peripheral nerve sheath tumors including neurofibromas, schwannomas, and malignant peripheral sheath tumors (MPNSTs) is predicated on knowing the specific pathology. Magnetic resonance imagining (MRI) has the potential to provide insight in the tumor type, yet imprecision in diagnosis remains. We assessed the accuracy of preoperative imaging diagnoses by comparing them with postoperative histopathologic diagnoses. We specifically focus on erroneous diagnosis of MPNSTs. Methods We reviewed all pathologically confirmed cases of nerve sheath tumors treated at our institution retrospectively from 2007 to 2015. Pre- and postoperative imaging data were reviewed for imaging-based diagnosis and compared with postresection pathologic diagnosis. Results The study included 127 patients: 82 diagnosed with neurofibroma, 17 with schwannoma, 24 with MPNST, and 4 with other histology types. A mean age of 40.8 ± 20.4 years, mean tumor size of 4.3 ± 3.6 cm, and mean follow-up of 29.1 ± 21.6 months were recorded. A family history of neurofibromatosis type 1 (NF1) was seen in 58 patients (46%). A discordant diagnosis from preoperative imaging and postoperative pathology was found in 65 individuals (51%). Most discordant diagnoses ( n  = 34) were inconclusive interpretation of preoperative imaging; however, 10 patients were diagnosed with a benign or unknown lesion on preoperative imaging but had an MPNST on histopathology. Patients with MPNST were more likely than those with benign pathologies to have larger lesions (7.6 ± 4.8 cm versus 3.5 ± 3.3 cm; p  = 0.004); however, a statistically acceptable threshold value could not be found to separate benign from malignant lesions. Clinical factors, such as NF1 status, did not meaningfully improve preoperative diagnosis. Conclusions These results suggest that routine MRI is insufficient to guide surgical decision making reliably. Additional imaging techniques may be necessary

Some Effects of Horizontal-Tail Position on the Vertical-Tail Pressure Distributions of a Complete Model in Sideslip at High Subsonic Speeds

NASA Technical Reports Server (NTRS)

Alford, William J., Jr.

1958-01-01

An investigation has been made in the Langley high-speed 7- by 10-foot tunnel of some effects of horizontal-tail position on the vertical-tail pressure distributions of a complete model in sideslip at high subsonic speeds. The wing of the model was swept back 28.82 deg at the quarter-chord line and had an aspect ratio of 3.50, a taper ratio of 0.067, and NACA 65A004 airfoil sections parallel to the model plane of symmetry. Tests were made with the horizontal tail off, on the wing-chord plane extended, and in T-tail arrangements in forward and rearward locations. The test Mach numbers ranged from 0.60 to 0.92, which corresponds to a Reynolds number range from approximately 2.93 x 10(exp 6) to 3.69 x 10(exp 6), based on the wing mean aerodynamic chord. The sideslip angles varied from -3.9 deg to 12.7 deg at several selected angles of attack. The results indicated that, for a given angle of sideslip, increases in angle of attack caused reductions in the vertical-tail loads in the vicinity of the root chord and increases at the midspan and tip locations, with rearward movements in the local chordwise centers of pressure for the midspan locations and forward movements near the tip of the vertical tail. At the higher angles of attack all configurations investigated experienced outboard and rearward shifts in the center of pressure of the total vertical-tail load. Location of the horizontal tail on the wing- chord plane extended produced only small effects on the vertical-tail loads and centers of pressure. Locating the horizontal tail at the tip of the vertical tail in the forward position caused increases in the vertical-tail loads; this configuration, however, experienced considerable reduction in loads with increasing Mach number. Location of the horizontal tail at the tip of the vertical tail in the rearward position produced the largest increases in vertical-tail loads per degree sideslip angle; this configuration experienced the smallest variations of loads with

A novel RNA binding protein affects rbcL gene expression and is specific to bundle sheath chloroplasts in C4 plants

PubMed Central

2013-01-01

Background Plants that utilize the highly efficient C4 pathway of photosynthesis typically possess kranz-type leaf anatomy that consists of two morphologically and functionally distinct photosynthetic cell types, the bundle sheath (BS) and mesophyll (M) cells. These two cell types differentially express many genes that are required for C4 capability and function. In mature C4 leaves, the plastidic rbcL gene, encoding the large subunit of the primary CO2 fixation enzyme Rubisco, is expressed specifically within BS cells. Numerous studies have demonstrated that BS-specific rbcL gene expression is regulated predominantly at post-transcriptional levels, through the control of translation and mRNA stability. The identification of regulatory factors associated with C4 patterns of rbcL gene expression has been an elusive goal for many years. Results RLSB, encoded by the nuclear RLSB gene, is an S1-domain RNA binding protein purified from C4 chloroplasts based on its specific binding to plastid-encoded rbcL mRNA in vitro. Co-localized with LSU to chloroplasts, RLSB is highly conserved across many plant species. Most significantly, RLSB localizes specifically to leaf bundle sheath (BS) cells in C4 plants. Comparative analysis using maize (C4) and Arabidopsis (C3) reveals its tight association with rbcL gene expression in both plants. Reduced RLSB expression (through insertion mutation or RNA silencing, respectively) led to reductions in rbcL mRNA accumulation and LSU production. Additional developmental effects, such as virescent/yellow leaves, were likely associated with decreased photosynthetic function and disruption of associated signaling networks. Conclusions Reductions in RLSB expression, due to insertion mutation or gene silencing, are strictly correlated with reductions in rbcL gene expression in both maize and Arabidopsis. In both plants, accumulation of rbcL mRNA as well as synthesis of LSU protein were affected. These findings suggest that specific accumulation

Do counts of salivary sheath flanges predict food consumption in herbivorous stink bugs [Hemiptera: Pentatomidae]?

USDA-ARS?s Scientific Manuscript database

For Pentatomid stink bug agricultural pests, the number of salivary sheaths and sheath flanges—the portion of the sheath visible on the exterior surface of a food item—are good predictors of the loss of crop yield or quality from stink bug feeding. As the often assumed relationship between salivary ...

Integration of nondegradable polystyrene and degradable gelatin in a core–sheath nanofibrous patch for pelvic reconstruction

PubMed Central

Ge, Liangpeng; Li, Qingtao; Jiang, Junzi; You, Xiaoyan; Liu, Zuohua; Zhong, Wen; Huang, Yong; Xing, Malcolm MQ

2015-01-01

Pelvic organ prolapse (POP) is a serious health issue affecting many adult women. Complications of POP include pelvic pressure, pelvic pain, and problems in emptying their bowels or bladder. Sometimes, POP may even cause urinary outflow obstruction and lead to bladder or kidney infections. Currently, synthetic and naturally derived materials have been chosen for treatment of POP to reduce the high recurrence rates after surgical interventions. However, existing materials for POP treatment cannot meet the clinical requirements in terms of biocompatibility, mechanics, and minimal risk of rejection. Especially, erosion in synthetic polymers and rapid degradation in natural polymers limit their further applications in clinics. To address these concerns, we report a novel POP replacement using core–sheath polystyrene/gelatin electrospun nanofiber mesh. The outside gelatin sheath provides a hydrophilic surface and implantable integrity between host and guest, while the inner PS core offers the necessary mechanical support. The composite mesh shows graft accommodation in pelvic submucosa after implantation in vivo, as shown in hematoxylin–eosin staining and T helper cell phenotype and macrophage phenotype stainings. Qualitative analysis of inducible nitric oxide synthase, arginase, interferon-γ, and interleukin-10 gene expressions also indicates that the implanted composite mesh switches to accommodation mode 2 weeks postimplantation. Thus, these novel core–sheath polystyrene/gelatin nanofibrous membranes are promising in pelvic reconstruction. PMID:25995629

A perturbative correction for electron-inertia in magnetized sheath structures

NASA Astrophysics Data System (ADS)

Gohain, Munmi; Karmakar, Pralay K.

2016-10-01

We propose a hydrodynamic model to study the equilibrium properties of planar plasma sheaths in two-component quasi-neutral magnetized plasmas. It includes weak but finite electron-inertia incorporated via a regular perturbation of the electronic fluid dynamics only relative to a new smallness parameter, δ, assessing the weak inertial-to-electromagnetic strengths. The zeroth-order perturbation around δ leads to the usual Boltzmann distribution law, which describes inertialess thermalized electrons. The forthwith next higher-order yields the modified Boltzmann law describing the putative lowest-order electron-inertial correction, which is applied meticulously to derive the local Bohm criterion for sheath formation. It is found to be influenced jointly by electron-inertial corrective effects, magnetic field and field orientation relative to the bulk plasma flow. We establish that the mutualistic action of electron-inertia amid gyro-kinetic effects slightly enhances the ion-flow Mach threshold value (typically, M i0 ⩾ 1.140), against the normal value of unity, confrontationally towards the sheath entrance. A numerical illustrative scheme is methodically constructed to see the parametric dependence of the new sheath properties on diverse problem arguments. The merits and demerits are highlighted in the light of the existing results conjointly with clear indication to future ameliorations.

Rectus sheath hematoma with low molecular weight heparin administration: a case series.

PubMed

Sullivan, Laura E J; Wortham, Dale C; Litton, Kayleigh M

2014-09-01

Rectus sheath hematoma is an uncommon but potentially serious bleeding complication that can occur spontaneously or as a result of anticoagulation administration. Case number one: A 62 year old chronically ill Caucasian female develops a rectus sheath hematoma seven days after hospital discharge. The previous hospitalization included low molecular weight heparin administration for deep vein thrombosis prophylaxis. The patient ultimately chooses comfort care and expires due to sepsis and respiratory failure. Case number two: A 79 year old Caucasian male develops a rectus sheath hematoma during hospital admission where LMWH is used for deep vein thrombosis prophylaxis. He is managed conservatively; however, his hematocrit drops from 46 to 25.8%. Case number three: A 44 year old chronically ill Caucasian female is treated with therapeutic low molecular weight heparin for recent deep vein thrombosis during a hospital admission. She develops a large rectus sheath hematoma requiring embolization as well as blood transfusion. We believe this reflects an underreported significant cause of morbidity and mortality with low molecular weight heparin administration. We review the pathophysiology of rectus sheath hematoma as well as its presentation, diagnosis, and treatment. We identify at-risk populations and proposed contributing factors. We also discuss factors leading to underreporting as well as preventive strategies implemented at our institution.

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

NASA Astrophysics Data System (ADS)

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.

Theory and Simulation of Electron Sheaths and Anode Spots in Low Pressure Laboratory Plasmas

NASA Astrophysics Data System (ADS)

Scheiner, Brett Stanford

Electrodes in low pressure laboratory plasmas have a multitude of possible sheath structures when biased at a large positive potential. When the size of the electrode is small enough the electrode bias can be above the plasma potential. When this occurs an electron-rich sheath called an electron sheath is present at the electrode. Electron sheaths are most commonly found near Langmuir probes and other electrodes collecting the electron saturation current. Such electrodes have applications in the control of plasma parameters, dust confinement and circulation, control of scrape off layer plasmas, RF plasmas, and in plasma contactors and tethered space probes. The electron sheaths in these various systems most directly influence the plasma by determining how electron current is lost from the system. An understanding of how the electron sheath interfaces with the bulk plasma is necessary for understanding the behavior induced by positively biased electrodes in these plasmas. This thesis provides a dedicated theory of electron sheaths. Motivated by electron velocity distribution functions (EVDFs) observed in particle-in-cell (PIC) simulations, a 1D model for the electron sheath and presheath is developed. In the presheath model, an electron pressure gradient accelerates electrons to near the electron thermal speed by the sheath edge. This pressure gradient generates large flow velocities compared to what would be generated by ballistic motion in response to the electric field. Using PIC simulations, the form of a sheath near a small electrode with bias near the plasma potential is also studied. When the electrode is biased near the plasma potential, the EVDFs exhibit a loss-cone type truncation due to fast electrons overcoming the small potential difference between the electrode and plasma. No sheath is present in this regime, instead the plasma remains quasineutral up to the electrode. Once the bias exceeds the plasma potential an electron sheath is present. In this

Tail gut cyst.

PubMed

Rao, G Mallikarjuna; Haricharan, P; Ramanujacharyulu, S; Reddy, K Lakshmi

2002-01-01

The tail gut is a blind extension of the hindgut into the tail fold just distal to the cloacal membrane. Remnants of this structure may form tail gut cyst. We report a 14-year-old girl with tail gut cyst that presented as acute abdomen. The patient recovered after cyst excision.

Telling tails: selective pressures acting on investment in lizard tails.

PubMed

Fleming, Patricia A; Valentine, Leonie E; Bateman, Philip W

2013-01-01

Caudal autotomy is a common defense mechanism in lizards, where the animal may lose part or all of its tail to escape entrapment. Lizards show an immense variety in the degree of investment in a tail (i.e., length) across species, with tails of some species up to three or four times body length (snout-vent length [SVL]). Additionally, body size and form also vary dramatically, including variation in leg development and robustness and length of the body and tail. Autotomy is therefore likely to have fundamentally different effects on the overall body form and function in different species, which may be reflected directly in the incidence of lost/regenerating tails within populations or, over a longer period, in terms of relative tail length for different species. We recorded data (literature, museum specimens, field data) for relative tail length (n=350 species) and the incidence of lost/regenerating tails (n=246 species). We compared these (taking phylogeny into account) with intrinsic factors that have been proposed to influence selective pressures acting on caudal autotomy, including body form (robustness, body length, leg development, and tail specialization) and ecology (foraging behavior, physical and temporal niches), in an attempt to identify patterns that might reflect adaptive responses to these different factors. More gracile species have relatively longer tails (all 350 spp., P < 0.001; also significant for five of the six families tested separately), as do longer (all species, P < 0.001; Iguanidae, P < 0.05; Lacertidae, P < 0.001; Scindidae, P < 0.001), climbing (all species, P < 0.05), and diurnal (all species, P < 0.01; Pygopodidae, P < 0.01) species; geckos without specialized tails (P < 0.05); or active-foraging skinks (P < 0.05). We also found some relationships with the data for caudal autotomy, with more lost/regenerating tails for nocturnal lizards (all 246 spp., P < 0.01; Scindidae, P < 0.05), larger skinks (P < 0.05), climbing geckos (P < 0

Purification and Properties of Mesophyll and Bundle Sheath Cell α-Glucan Phosphorylases from Zea mays L. 1

PubMed Central

Mateyka, Christian; Schnarrenberger, Claus

1988-01-01

Two major α-glucan phosphorylases (I and II) from leaves of the C4 plant corn (Zea mays L.) were previously shown to be compartmented in mesophyll and bundle sheath cells, respectively (C Mateyka, C Schnarrenberger 1984 Plant Sci Lett 36: 119-123). The two enzymes were separated by chromatography on DEAE-cellulose and purified to homogeneity by affinity chromatography on immobilized starch, according to published procedures, as developed for the cytosol and chloroplast phosphorylase from the C3 plant spinach. The two α-glucan phosphorylases have their pH optimum at pH 7. The specificity for polyglucans was similar for soluble starch and amylopectin, however, differed for glycogen (Km = 16 micrograms per milliliter for the mesophyll cell and 250 micrograms per milliliter for the bundle sheath cell phosphorylase). Maltose, maltotriose, and maltotetraose were not cleaved by either phosphorylase. If maltopentaose was used as substrate, the rate was about twice as high with the bundle sheath cell phosphorylase, than with the mesophyll cell phosphorylase. The phosphorylase I showed a molecular mass of 174 kilodaltons and the phosphorylase II of 195 kilodaltons for the native enzyme and of 87 and of 53 kilodaltons for the SDS-treated proteins, respectively. Specific antisera raised against mesophyll cell phosphorylase from corn leaves and against chloroplast phosphorylase from spinach leaves implied high similarity for the cytosol phosphorylase of the C3 plant spinach with mesophyll cell phosphorylase of the C4 plant corn and of chloroplast phosphorylase of spinach with the bundle sheath cell phosphorylase of corn. Images Fig. 2 Fig. 7 PMID:16665923

Giant cell tumour of tendon sheath and synovial membrane: A review of 26 cases.

PubMed

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.

Isolation of Mesophyll Cells and Bundle Sheath Cells from Digitaria sanguinalis (L.) Scop. Leaves and a Scanning Microscopy Study of the Internal Leaf Cell Morphology 1

PubMed Central

Edwards, Gerald E.; Black, Clanton C.

1971-01-01

A technique is described for the separation of mesophyll and bundle sheath cells from Digitaria sanguinalis leaves and evidence for separation is given with light and scanning electron micrographs. Gentle grinding of fully differentiated leaves in a mortar releases mesophyll cells which are isolated on nylon nets by filtration. More extensive grinding of the remaining tissue yields bundle sheath strands which are isolated by filtration with stainless steel sieves and nylon nets. Further grinding of bundle sheath strands in a tissue homogenizer releases bundle sheath cells which are collected on nylon nets. Percentage of purity derived from cell counts and yield data on a chlorophyll basis are given. The internal leaf cell morphology is presented in scanning electron micrographs and compared with light micrographs of fully-differentiated D. sanguinalis leaves. In leaves of plants which possess the C4-dicarboxylic acid cycle of photosynthesis, the relationship of leaf morphology to photosynthesis in mesophyll and bundle sheath cells is considered, and the hypothesis is presented that as atmospheric CO2 enters a leaf about 85% is fixed by the C4-dicarboxylic acid cycle in the mesophyll cells and 10 to 15% is fixed by the reductive pentose phosphate cycle in the bundle sheath cells. A technique also is given for the isolation of mesophyll cells from spinach leaves. Images PMID:16657571

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

PubMed Central

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

2017-01-01

Purpose 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. Methods 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. Results 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. Conclusions 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. PMID:27422970

An Architectonic Study of the Neocortex of the Short-Tailed Opossum (Monodelphis domestica)

PubMed Central

Wong, Peiyan; Kaas, Jon H.

2013-01-01

Short-tailed opossums (Monodelphis domestica) belong to the branch of marsupial mammals that diverged from eutherian mammals approximately 180 million years ago. They are small in size, lack a marsupial pouch, and may have retained more morphological characteristics of early marsupial neocortex than most other marsupials. In the present study, we used several different histochemical and immunochemical procedures to reveal the architectonic characteristics of cortical areas in short-tailed opossums. Subdivisions of cortex were identified in brain sections cut in the coronal, sagittal, horizontal or tangential planes and processed for a calcium-binding protein, parvalbumin (PV), neurofilament protein epitopes recognized by SMI-32, the vesicle glutamate transporter 2 (VGluT2), myelin, cytochrome oxidase (CO), and Nissl substance. These different procedures revealed similar boundaries among areas, suggesting that functionally relevant borders were detected. The results allowed a fuller description and more precise demarcation of previously identified sensory areas, and the delineation of additional subdivisions of cortex. Area 17 (V1) was especially prominent, with a densely populated layer 4, high myelination levels, and dark staining of PV and VGluT2 immunopositive terminations. These architectonic features were present, albeit less pronounced, in somatosensory and auditory cortex. The major findings support the conclusion that short-tailed opossums have fewer cortical areas and their neocortex is less distinctly laminated than most other mammals. PMID:19546531

A salivary sheath protein essential for the interaction of the brown planthopper with rice plants.

PubMed

Huang, Hai-Jian; Liu, Cheng-Wen; Cai, Ye-Fang; Zhang, Min-Zhu; Bao, Yan-Yuan; Zhang, Chuan-Xi

2015-11-01

Salivary secretions, including gel saliva and watery saliva, play crucial roles in the interaction between the insect and plant during feeding. In this study, we identified a salivary gland-specific gene encoding a salivary sheath protein (NlShp) in Nilaparvata lugens. NlShp has two alternative splicing variants; both are expressed at high levels during the nymph and adult stages. Immunohistochemical staining showed that the NlShp were synthesized in the principal gland cells of the salivary gland. LC-MS/MS and western blot analysis confirmed that NlShp was one of the components of the salivary sheath. Simultaneously knocking down the two NlShp variants by RNA interference inhibited both salivary flange and salivary sheath formation and resulted in a lethal phenotype within four days for the brown planthopper (BPH) feeding on rice plants, indicating that the salivary sheath and salivary flanges were essential for plant-associated feeding. Despite the salivary sheath deficiency, no obvious phenotype was observed in the NlShp-knockdown BPHs fed on artificial diet. The electrical penetration graph (EPG) results showed that salivary sheath-deficient BPHs exhibited a prolonged nonpenetration period, scarce sap period, and increased stylet movement on rice plants and eventually starved to death. Our results provided evidence that the interaction between the salivary sheath and host plant might be a critical step in successful BPH feeding. According to present research, we propose a salivary sheath required feeding model for piercing-sucking insects and provide a potential target for rice planthopper management. Copyright © 2015 Elsevier Ltd. All rights reserved.

Oral or parenteral administration of curcumin does not prevent the growth of high-risk t(4;11) acute lymphoblastic leukemia cells engrafted into a NOD/SCID mouse model

USDA-ARS?s Scientific Manuscript database

The efficacy of orally and parenterally administered curcumin was evaluated in NOD.CB17-Prkdcscid/J mice engrafted with the human t(4;11) acute lymphoblastic leukemia line SEM. SEM cells were injected into the tail vein and engraftment was monitored by flow cytometry. Once engraftment was observed...

21 CFR 884.5320 - Glans sheath.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Glans sheath. 884.5320 Section 884.5320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5320 Glans...

21 CFR 884.5320 - Glans sheath.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Glans sheath. 884.5320 Section 884.5320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5320 Glans...

21 CFR 884.5320 - Glans sheath.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Glans sheath. 884.5320 Section 884.5320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5320 Glans...

21 CFR 884.5320 - Glans sheath.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Glans sheath. 884.5320 Section 884.5320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Obstetrical and Gynecological Therapeutic Devices § 884.5320 Glans...

Particle trap to sheath contact for a gas-insulated transmission line having a corrugated outer conductor

DOEpatents

Fischer, William H.; Cookson, Alan H.; Yoon, Kue H.

1984-04-10

A particle trap to outer elongated conductor or sheath contact for gas-insulated transmission lines. The particle trap to outer sheath contact of the invention is applicable to gas-insulated transmission lines having either corrugated or non-corrugated outer sheaths. The contact of the invention includes an electrical contact disposed on a lever arm which in turn is rotatably disposed on the particle trap and biased in a direction to maintain contact between the electrical contact and the outer sheath.

Studies of RF sheaths and diagnostics on IShTAR

NASA Astrophysics Data System (ADS)

Crombé, K.; Devaux, S.; D'Inca, R.; Faudot, E.; Faugel, H.; Fünfgelder, H.; Heuraux, S.; Jacquot, J.; Louche, F.; Moritz, J.; Ochoukov, R.; Tripsky, M.; Van Eester, D.; Wauters, T.; Noterdaeme, J.-M.

2015-12-01

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.

Studies of RF sheaths and diagnostics on IShTAR

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

Crombé, K., E-mail: Kristel.Crombe@UGent.be; LPP-ERM/KMS, Royal Military Academy, Brussels; Devaux, S.

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 tomore » 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.« less

Dual mTORC1/2 inhibition induces anti-proliferative effect in NF1-associated plexiform neurofibroma and malignant peripheral nerve sheath tumor cells

PubMed Central

Hivelin, Mikael; Nusbaum, Patrick; Hubas, Arnaud; Laurendeau, Ingrid; Lantieri, Laurent; Wolkenstein, Pierre; Vidaud, Michel; Pasmant, Eric; Chapuis, Nicolas; Parfait, Béatrice

2016-01-01

Approximately 30-50% of individuals with Neurofibromatosis type 1 develop benign peripheral nerve sheath tumors, called plexiform neurofibromas (PNFs). PNFs can undergo malignant transformation to highly metastatic malignant peripheral nerve sheath tumors (MPNSTs) in 5-10% of NF1 patients, with poor prognosis. No effective systemic therapy is currently available for unresectable tumors. In tumors, the NF1 gene deficiency leads to Ras hyperactivation causing the subsequent activation of the AKT/mTOR and Raf/MEK/ERK pathways and inducing multiple cellular responses including cell proliferation. In this study, three NF1-null MPNST-derived cell lines (90-8, 88-14 and 96-2), STS26T sporadic MPNST cell line and PNF-derived primary Schwann cells were used to test responses to AZD8055, an ATP-competitive “active-site” mTOR inhibitor. In contrast to rapamycin treatment which only partially affected mTORC1 signaling, AZD8055 induced a strong inhibition of mTORC1 and mTORC2 signaling in MPNST-derived cell lines and PNF-derived Schwann cells. AZD8055 induced full blockade of mTORC1 leading to an efficient decrease of global protein synthesis. A higher cytotoxic effect was observed with AZD8055 compared to rapamycin in the NF1-null MPNST-derived cell lines with IC50 ranging from 70 to 140 nM and antiproliferative effect was confirmed in PNF-derived Schwann cells. Cell migration was impaired by AZD8055 treatment and cell cycle analysis showed a G0/G1 arrest. Combined effects of AZD8055 and PD0325901 MEK inhibitor as well as BRD4 (BromoDomain-containing protein 4) inhibitors showed a synergistic antiproliferative effect. These data suggest that NF1-associated peripheral nerve sheath tumors are an ideal target for AZD8055 as a single molecule or in combined therapies. PMID:26840085

FDVIBSPC16: Sheath Flow SERS for Chemical Profiling in Urine

PubMed Central

Riordan, Colleen M.; Jacobs, Kevin T.; Negri, Pierre; Schultz, Zachary D.

2016-01-01

The molecular specificity and sensitivity of surface enhanced Raman scattering (SERS) makes it an attractive method for biomedical diagnostics. Here we present results demonstrating the utility and complications for SERS characterization in urine. The chemical fingerprint characteristic of Raman spectra suggests use as a label free diagnostic; however, the complex composition of biological fluids presents a tremendous challenge. In particular, the limited number of surface sites and competing absorption tend to mask the presence of analytes in solution, particularly when the solution contains multiple analytes. To address these problems and characterize biological fluids we have demonstrated a sheath-flow interface for SERS detection. This sheath-flow SERS interface uses hydrodynamic focusing to confine analyte molecules eluting out of a column onto a planar SERS substrate where the molecules are detected by their intrinsic SERS signal. In this report we compare direct detection of benzoylecgonine in urine using DSERS with chemical profiling by capillary zone electrophoresis and sheath-flow SERS detection. The SERS spectrum from the observed migration peaks can identify benzoylecgonine and other distinct spectra are also observed, suggesting improved chemical diagnostics in urine. With over 2000 reported compounds in urine, identification of each of the detected species is an enormous task. Nonetheless, these samples provide a benchmark to establish the potential clinical utility of sheath-flow SERS detection. PMID:27034996

The episodic evolution of fibritin: traces of ancient global environmental alterations may remain in the genomes of T4-like phages

PubMed Central

Letarov, A V; Krisch, H M

2013-01-01

The evolutionary adaptation of bacteriophages to their environment is achieved by alterations of their genomes involving a combination of both point mutations and lateral gene transfer. A phylogenetic analysis of a large set of collar fiber protein (fibritin) loci from diverse T4-like phages indicates that nearly all the modular swapping involving the C-terminal domain of this gene occurred in the distant past and has since ceased. In phage T4, this fibritin domain encodes the sequence that mediates both the attachment of the long tail fibers to the virion and also controls, in an environmentally sensitive way, the phage's ability to infect its host bacteria. Subsequent to its distant period of modular exchange, the evolution of fibritin has proceeded primarily by the slow vertical divergence mechanism. We suggest that ancient and sudden changes in the environment forced the T4-like phages to alter fibritin's mode of action or function. The genome's response to such episodes of rapid environmental change could presumably only be achieved quickly enough by employing the modular evolution mechanism. A phylogenetic analysis of the fibritin locus reveals the possible traces of such events within the T4 superfamily's genomes. PMID:24223296

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

PubMed

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.

Expression of tyrosine hydroxylase in CD4+ T cells contributes to alleviation of Th17/Treg imbalance in collagen-induced arthritis.

PubMed

Wang, Xiao-Qin; Liu, Yan; Cai, Huan-Huan; Peng, Yu-Ping; Qiu, Yi-Hua

2016-12-01

Tyrosine hydroxylase (TH), a rate-limiting enzyme for the synthesis of catecholamines, is expressed in T lymphocytes. However, the role of T cell-expressed TH in rheumatoid arthritis (RA) is less clear. Herein, we aimed to show the contribution of TH expression by CD4 + T cells to alleviation of helper T (Th)17/regulatory T (Treg) imbalance in collagen-induced arthritis (CIA), a mouse model of RA. CIA was prepared by intradermal injection of collagen type II (CII) at tail base of DBA1/J mice. Expression of TH in the spleen and the ankle joints was measured by real-time polymerase chain reaction and Western blot analysis. Percentages of TH-expressing Th17 and Treg cells in splenic CD4 + T cells were determined by flow cytometry. Overexpression and knockdown of TH gene in CD4 + T cells were taken to evaluate effects of TH on Th17 and Treg cells in CIA. TH expression was upregulated in both the inflamed tissues (spleen and ankle joints) and the CD4 + T cells of CIA mice. In splenic CD4 + T cells, the cells expressing TH were increased during CIA. These cells that expressed more TH in CIA were mainly Th17 cells rather than Treg cells. TH gene overexpression in CD4 + T cells from CIA mice reduced Th17 cell percentage as well as Th17-related transcription factor and cytokine expression and secretion, whereas TH gene knockdown enhanced the Th17 cell activity. In contrast, TH gene overexpression increased Treg-related cytokine expression and secretion in CD4 + T cells of CIA mice, while TH gene knockdown decreased the Treg cell changes. Collectively, these findings show that CIA induces TH expression in CD4 + T cells, particularly in Th17 cells, and suggest that the increased TH expression during CIA represents an anti-inflammatory mechanism.

Aerodynamics of an Axisymmetric Missile Concept Having Cruciform Strakes and In-Line Tail Fins From Mach 0.60 to 4.63

NASA Technical Reports Server (NTRS)

Allen, Jerry M.

2005-01-01

An experimental study has been performed to develop a large force and moment aerodynamic data set on a slender axisymmetric missile configuration having cruciform strakes and in-line control tail fins. The data include six-component balance measurements of the configuration aerodynamics and three-component measurements on all four tail fins. The test variables include angle of attack, roll angle, Mach number, model buildup, strake length, nose size, and tail fin deflection angles to provide pitch, yaw, and roll control. Test Mach numbers ranged from 0.60 to 4.63. The entire data set is presented on a CD-ROM that is attached to this paper. The CD-ROM also includes extensive plots of both the six-component configuration data and the three-component tail fin data. Selected samples of these plots are presented in this paper to illustrate the features of the data and to investigate the effects of the test variables.

Spontaneous rectus sheath hematoma: The utility of CT angiography.

PubMed

Pierro, Antonio; Cilla, Savino; Modugno, Pietro; Centritto, Enrico Maria; De Filippo, Carlo Maria; Sallustio, Giuseppina

2018-04-01

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.

Recent sheath physics studies on DIII-D

NASA Astrophysics Data System (ADS)

Watkins, J. G.; Labombard, B.; Stangeby, P. C.; Lasnier, C. J.; McLean, A. G.; Nygren, R. E.; Boedo, J. A.; Leonard, A. W.; Rudakov, D. L.

2015-08-01

A study to examine some current issues in the physics of the plasma sheath has been recently carried out in DIII-D low power Ohmic plasmas using both flush and domed Langmuir probes, divertor Thomson scattering (DTS), an infrared camera (IRTV), and a new calorimeter triple probe assembly mounted on the Divertor Materials Evaluation System (DIMES). The sheath power transmission factor was found to be consistent with the theoretically predicted value of 7 (±2) for low power plasmas. Using this factor, the three heat flux profiles derived from the LP, DTS, and calorimeter diagnostic measurements agree. Comparison of flush and domed Langmuir probes and divertor Thomson scattering indicates that proper interpretation of flush probe data to get target plate density and temperature is feasible and could potentially yield accurate measurements of target plate conditions where the probes are located.

Optic Nerve Sheath Mechanics in VIIP Syndrome

NASA Technical Reports Server (NTRS)

Raykin, Julia; Feola, Andrew; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian; Ethier, C. Ross

2015-01-01

Visual Impairment and Intracranial Pressure (VIIP) syndrome results in a loss of visual function and occurs in astronauts following long-duration spaceflight. Understanding the mechanisms that lead to the ocular changes involved in VIIP is of critical importance for space medicine research. Although the exact mechanisms of VIIP are not yet known, it is hypothesized that microgravity-induced increases in intracranial pressures (ICP) drive the remodeling of the optic nerve sheath, leading to compression of the optic nerve which in turn may reduce visual acuity. Some astronauts present with a kink in the optic nerve after return to earth, suggesting that tissue remodeling in response to ICP increases may be taking place. The goal of this work is to characterize the mechanical properties of the optic nerve sheath (dura mater) to better understand its biomechanical response to increased ICP.

Decreased bed rest post-percutaneous coronary intervention with a 7-French arterial sheath and its effects on vascular complications.

PubMed

Wentworth, Laura J; Bechtum, Elizabeth L; Hoffman, Jessica G; Kramer, Robert R; Bartel, David C; Slusser, Joshua P; Tilbury, Ralph Thomas

2018-01-01

To compare the incidence of femoral access puncture site complications in the control group, who underwent 6 hr of bed rest, with patients in the case group, who underwent 4 hr of bed rest. The ideal bed rest length after percutaneous coronary intervention with a 7-French arterial sheath has been investigated by nursing practice. However, in this larger-sheath-size group, best practices have not been determined, and bed rest time continues to vary markedly among institutions. Retrospective study. Data were retrieved from the National Cardiovascular Data Registry and electronic health records in this retrospective study. Sample size was 401 patients: 152 case patients with 4-hr bed rest and 249 controls with 6-hr bed rest. Case group data were obtained from 20 May 2013-31 December 2014; and control group data, 15 June 2011-20 May 2013. National Cardiovascular Data Registry event rates were generally low in both groups: Only three patients in each group had a bleeding event within 72 hr (2% vs. 1%) and no patient and only two controls had arteriovenous fistula (0% vs. 1%). Complications documented in the electronic health records with institutional femoral access puncture site complication definitions identified bleeding at the access site in eight case patients (5%) and nine controls (4%). Haematoma at the access site occurred in 21 case patients (14%) and 25 controls (10%). The practice change of decreasing bed rest from 6-4 hr for patients with 7-French arterial sheaths post-percutaneous coronary intervention was associated with no significant change in femoral access puncture site complications in either National Cardiovascular Data Registry data or institutional electronic health records data. This introduces expanded evidence of safety in decreasing bed rest length in larger (7-French) arterial sheaths post-percutaneous coronary intervention. © 2017 John Wiley & Sons Ltd.

T4-Like Genome Organization of the Escherichia coli O157:H7 Lytic Phage AR1▿†

PubMed Central

Liao, Wei-Chao; Ng, Wailap Victor; Lin, I-Hsuan; Syu, Wan-Jr; Liu, Tze-Tze; Chang, Chuan-Hsiung

2011-01-01

We report the genome organization and analysis of the first completely sequenced T4-like phage, AR1, of Escherichia coli O157:H7. Unlike most of the other sequenced phages of O157:H7, which belong to the temperate Podoviridae and Siphoviridae families, AR1 is a T4-like phage known to efficiently infect this pathogenic bacterial strain. The 167,435-bp AR1 genome is currently the largest among all the sequenced E. coli O157:H7 phages. It carries a total of 281 potential open reading frames (ORFs) and 10 putative tRNA genes. Of these, 126 predicted proteins could be classified into six viral orthologous group categories, with at least 18 proteins of the structural protein category having been detected by tandem mass spectrometry. Comparative genomic analysis of AR1 and four other completely sequenced T4-like genomes (RB32, RB69, T4, and JS98) indicated that they share a well-organized and highly conserved core genome, particularly in the regions encoding DNA replication and virion structural proteins. The major diverse features between these phages include the modules of distal tail fibers and the types and numbers of internal proteins, tRNA genes, and mobile elements. Codon usage analysis suggested that the presence of AR1-encoded tRNAs may be relevant to the codon usage of structural proteins. Furthermore, protein sequence analysis of AR1 gp37, a potential receptor binding protein, indicated that eight residues in the C terminus are unique to O157:H7 T4-like phages AR1 and PP01. These residues are known to be located in the T4 receptor recognition domain, and they may contribute to specificity for adsorption to the O157:H7 strain. PMID:21507986

30 CFR 75.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

Code of Federal Regulations, 2010 CFR

2010-07-01

... conduits enclosing power conductors. 75.700 Section 75.700 Mineral Resources MINE SAFETY AND HEALTH... Grounding § 75.700 Grounding metallic sheaths, armors, and conduits enclosing power conductors. [Statutory Provisions] All metallic sheaths, armors, and conduits enclosing power conductors shall be electrically...

30 CFR 75.700 - Grounding metallic sheaths, armors, and conduits enclosing power conductors.

Code of Federal Regulations, 2011 CFR

2011-07-01

... conduits enclosing power conductors. 75.700 Section 75.700 Mineral Resources MINE SAFETY AND HEALTH... Grounding § 75.700 Grounding metallic sheaths, armors, and conduits enclosing power conductors. [Statutory Provisions] All metallic sheaths, armors, and conduits enclosing power conductors shall be electrically...

Investigation of particle lateral migration in sample-sheath flow of viscoelastic fluid and Newtonian fluid.

PubMed

Yuan, Dan; Zhang, Jun; Yan, Sheng; Peng, Gangrou; Zhao, Qianbin; Alici, Gursel; Du, Hejun; Li, Weihua

2016-08-01

In this work, particle lateral migration in sample-sheath flow of viscoelastic fluid and Newtonian fluid was experimentally investigated. The 4.8-μm micro-particles were dispersed in a polyethylene oxide (PEO) viscoelastic solution, and then the solution was injected into a straight rectangular channel with a deionised (DI) water Newtonian sheath flow. Micro-particles suspended in PEO solution migrated laterally to a DI water stream, but migration in the opposite direction from a DI water stream to a PEO solution stream or from one DI water stream to another DI water stream could not be achieved. The lateral migration of particles depends on the viscoelastic properties of the sample fluids. Furthermore, the effects of channel length, flow rate, and PEO concentration were studied. By using viscoelastic sample flow and Newtonian sheath flow, a selective particle lateral migration can be achieved in a simple straight channel, without any external force fields. This particle lateral migration technique could be potentially used in solution exchange fields such as automated cell staining and washing in microfluidic platforms, and holds numerous biomedical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coronal Axis Measurement of the Optic Nerve Sheath Diameter Using a Linear Transducer.

PubMed

Amini, Richard; Stolz, Lori A; Patanwala, Asad E; Adhikari, Srikar

2015-09-01

The true optic nerve sheath diameter cutoff value for detecting elevated intracranial pressure is variable. The variability may stem from the technique used to acquire sonographic measurements of the optic nerve sheath diameter as well as sonographic artifacts inherent to the technique. The purpose of this study was to compare the traditional visual axis technique to an infraorbital coronal axis technique for assessing the optic nerve sheath diameter using a high-frequency linear array transducer. We conducted a cross-sectional study at an academic medical center. Timed optic nerve sheath diameter measurements were obtained on both eyes of healthy adult volunteers with a 10-5-MHz broadband linear array transducer using both traditional visual axis and coronal axis techniques. Optic nerve sheath diameter measurements were obtained by 2 sonologists who graded the difficulty of each technique and were blinded to each other's measurements for each participant. A total of 42 volunteers were enrolled, yielding 84 optic nerve sheath diameter measurements. There were no significant differences in the measurements between the techniques on either eye (P = .23 [right]; P = .99 [left]). Additionally, there was no difference in the degree of difficulty obtaining the measurements between the techniques (P = .16). There was a statistically significant difference in the time required to obtain the measurements between the traditional and coronal techniques (P < .05). Infraorbital coronal axis measurements are similar to measurements obtained in the traditional visual axis. The infraorbital coronal axis technique is slightly faster to perform and is not technically challenging. © 2015 by the American Institute of Ultrasound in Medicine.

Comparison of the analgesic efficacy of ultrasound-guided rectus sheath block and local anesthetic infiltration for laparoscopic percutaneous extraperitoneal closure in children.

PubMed

Uchinami, Yuka; Sakuraya, Fumika; Tanaka, Nobuhiro; Hoshino, Koji; Mikami, Eri; Ishikawa, Taro; Fujii, Hitomi; Ishikawa, Takehiko; Morimoto, Yuji

2017-05-01

Ultrasound-guided rectus sheath block and local anesthetic infiltration are the standard options to improve postoperative pain for children undergoing surgery with a midline incision. However, there is no study comparing the effect of ultrasound-guided rectus sheath block with local anesthetic infiltration for children undergoing laparoscopic surgery. The aim of this trial was to compare the onset of ultrasound-guided rectus sheath block with that of local anesthetic infiltration for laparoscopic percutaneous extraperitoneal closure in children. We performed an observer-blinded, randomized, prospective trial. Enrolled patients were assigned to either an ultrasound-guided rectus sheath block group or a local anesthetic infiltration group. The ultrasound-guided rectus sheath block group (n = 17) received ultrasound-guided rectus sheath block with 0.2 ml·kg -1 of 0.375% ropivacaine per side in the posterior rectus sheath compartment. The local anesthetic infiltration group (n = 17) received local anesthetic infiltration with 0.2 ml·kg -1 of 0.75% ropivacaine. The Face, Legs, Activity, Cry, and Consolability (FLACC) pain scores were recorded at 0, 30, 60 min after arrival at the postanesthesia care unit. Of the 37 patients enrolled in this study, 34 completed the study protocol. A significant difference in the pain scale between the ultrasound-guided rectus sheath block group and local anesthetic infiltration group was found at 0 min (median: 0, interquartile range [IQR]: 0-1.5, vs median: 1, IQR 0-5, confidence interval of median [95% CI]: 0-3, P = 0.048), but no significant difference was found at 30 min (median: 1, IQR: 0-4 vs median: 6, IQR: 0-7, 95% CI: 0-5, P = 0.061), or 60 min (median: 0, IQR: 0-2 vs median: 1, IQR: 0-3, 95% CI: -1 to 1, P = 0.310). No significant difference was found in anesthesia time between the ultrasound-guided rectus sheath block and local anesthetic infiltration groups. No procedure-related complications were observed in either group

Black-tailed and white-tailed jackrabbits in the American West: History, ecology, ecological significance, and survey methods

USGS Publications Warehouse

Simes, Matthew; Longshore, Kathleen M.; Nussear, Kenneth E.; Beatty, Greg L.; Brown, David E.; Esque, Todd C.

2015-01-01

Across the western United States, Leporidae are the most important prey item in the diet of Golden Eagles (Aquila chrysaetos). Leporids inhabiting the western United States include black-tailed (Lepus californicus) and white-tailed jackrabbits (Lepus townsendii) and various species of cottontail rabbit (Sylvilagus spp.). Jackrabbits (Lepus spp.) are particularly important components of the ecological and economic landscape of western North America because their abundance influences the reproductive success and population trends of predators such as coyotes (Canis latrans), bobcats (Lynx rufus), and a number of raptor species. Here, we review literature pertaining to black-tailed and white-tailed jackrabbits comprising over 170 published journal articles, notes, technical reports, conference proceedings, academic theses and dissertations, and other sources dating from the late 19th century to the present. Our goal is to present information to assist those in research and management, particularly with regard to protected raptor species (e.g., Golden Eagles), mammalian predators, and ecological monitoring. We classified literature sources as (1) general information on jackrabbit species, (2) black-tailed or (3) white-tailed jackrabbit ecology and natural history, or (4) survey methods. These categories, especially 2, 3, and 4, were further subdivided as appropriate. The review also produced several tables on population trends, food habits, densities within various habitats, and jackrabbit growth and development. Black-tailed and white-tailed jackrabbits are ecologically similar in general behaviors, use of forms, parasites, and food habits, and they are prey to similar predators; but they differ in their preferred habitats. While the black-tailed jackrabbit inhabits agricultural land, deserts, and shrublands, the white-tailed jackrabbit is associated with prairies, alpine tundra, and sagebrush-steppe. Frequently considered abundant, jackrabbit numbers in western North

Effect of sheath gas in atmospheric-pressure plasma jet for potato sprouting suppression

NASA Astrophysics Data System (ADS)

Nishiyama, S.; Monma, M.; Sasaki, K.

2016-09-01

Recently, low-temperature atmospheric-pressure plasma jets (APPJs) attract much interest for medical and agricultural applications. We try to apply APPJs for the suppression of potato sprouting in the long-term storage. In this study, we investigated the effect of sheath gas in APPJ on the suppression efficiency of the potato sprouting. Our APPJ was composed of an insulated thin wire electrode, a glass tube, a grounded electrode which was wound on the glass tube, and a sheath gas nozzle which was attached at the end of the glass tube. The wire electrode was connected to a rectangular-waveform power supply at a frequency of 3 kHz and a voltage of +/- 7 kV. Helium was fed through the glass tube, while we tested dry nitrogen, humid nitrogen, and oxygen as the sheath gas. Eyes of potatoes were irradiated by APPJ for 60 seconds. The sprouting probability was evaluated at two weeks after the plasma irradiation. The sprouting probability was 28% when we employed no sheath gases, whereas an improved probability of 10% was obtained when we applied dry nitrogen as the sheath gas. Optical emission spectroscopy was carried out to diagnose the plasma jet. It was suggested that reactive species originated from nitrogen worked for the efficient suppression of the potato sprouting.

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

PubMed

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/.

Enhancing resolution of free-flow zone electrophoresis via a simple sheath-flow sample injection.

PubMed

Yang, Ying; Kong, Fan-Zhi; Liu, Ji; Li, Jun-Min; Liu, Xiao-Ping; Li, Guo-Qing; Wang, Ju-Fang; Xiao, Hua; Fan, Liu-Yin; Cao, Cheng-Xi; Li, Shan

2016-07-01

In this work, a simple and novel sheath-flow sample injection method (SFSIM) is introduced to reduce the band broadening of free-flow zone electrophoresis separation in newly developed self-balance free-flow electrophoresis instrument. A needle injector was placed in the center of the separation inlet, into which the BGE and sample solution were pumped simultaneously. BGE formed sheath flow outside the sample stream, resulting in less band broadening related to hydrodynamics and electrodynamics. Hemoglobin and C-phycocyanin were successfully separated by the proposed method in contrast to the poor separation of free-flow electrophoresis with the traditional injection method without sheath flow. About 3.75 times resolution enhancement could be achieved by sheath-flow sample injection method. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Association between QTLs and morphological traits toward sheath blight resistance in rice (Oryza sativa L.)

PubMed Central

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

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK ...

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

REAR PROFILE OF TAIL FROM SECOND LEVEL OF TAIL DOCK STAND, SHOWING AIRCRAFT NUMBER (319), HORIZONTAL STABILIZER, TAIL CONE AND COOLING CTS FOR THE AUXILIARY POWER UNIT (APU), MECHANIC PAUL RIDEOUT IS LOWERING THE BALANCE PANELS ON THE STABILIZERS FOR LUBRICATION AND INSPECTION. - Greater Buffalo International Airport, Maintenance Hangar, Buffalo, Erie County, NY

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

PubMed

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.

Ulysses feels the brush of a comet's tail

NASA Astrophysics Data System (ADS)

2000-04-01

"Ulysses's prime task is to map the solar wind above the Sun's poles: it had not been looking for Hyakutake, which happened to be at its closest approach to the Sun on 1 May 1996, or any other comet", says Richard Marsden, ESA's Ulysses Project Scientist. "Ulysses was just in the right place at the right time." The two teams stumbled across the telltale signature of a comet quite independently when poring over old Ulysses data. Jones and colleagues found their evidence in magnetic field data: "the magnetic field lines were draped in a way that you'd expect in a comet's tail," says Jones. The other instrument team, lead by George Gloeckler from the University of Maryland, found their evidence when looking at the composition of the solar wind. Cometary tails are rich in oxygen and carbon compared with the solar wind, but depleted in nitrogen and neon. The Imperial College team identified Hyakutake as the source of the anomalous readings. On 1 May 1996, Ulysses was aligned with the Sun and the position Hyakutake had occupied eight days earlier, which Jones calculated was the time needed for material leaving the comet's nucleus to travel the distance to Ulysses. One of the most surprising aspects of the discovery is the length of Hyakutake's tail. Cometary experts had thought that comet tails eventually spread out and lose their integrity. "We found that the whole thing is preserved as an entity and doesn't spread out very much," says Gloeckler. "If it can persist as far as Ulysses, there's no reason to presume that it wouldn't continue to the edge of the heliosphere (the boundary about 100AU from the Sun between the solar wind and the interstellar medium)," says Jones. "This discovery makes us wonder whether Ulysses or other spacecraft have crossed a comet tail before. So we're going back to look again for other signatures. But it's probably a rare event," says Jones. The comet nucleus has to be in exactly the right position with respect to the Sun and the spacecraft

Unified Model of the rf Plasma Sheath, Part II

NASA Astrophysics Data System (ADS)

Riley, Merle

1996-10-01

By developing an approximation to the first integral of the Poisson equation, one can obtain solutions for the current-voltage characteristics of an rf plasma sheath that are valid over the whole range of inertial response of the ions to an imposed rf voltage or current. (M.E.Riley, 1995 GEC, abstract QA5, published in Bull. Am. Phys. Soc., 40, 1587 (1995).) The theory has been shown to adequately reproduce current-voltage characteristics of two extreme cases (M.A. Lieberman, IEEE Trans. Plasma Sci. 16, 638 (1988). A. Metze, D.W. Ernie, and H.J.Oskam, J.Appl.Phys., 60, 3081 (1986).) of ion response. In this work I show the effect of different conventions for connecting the sheath model to the bulk plasma. Modifications of the Mach number and a finite electric field at the Bohm point are natural choices. The differences are examined for a sheath in a high density Ar plasma and are found to be insignificant. A theoretical argument favors the electric field modification. *Work performed at Sandia National Labs and supported by US DoE under contract DE-AC04-94AL85000.

Effects of estrogen replacement therapy on the myelin sheath ultrastructure of myelinated fibers in the white matter of middle-aged ovariectomized rats.

PubMed

He, Qi; Luo, Yanmin; Lv, Fulin; Xiao, Qian; Chao, Fenglei; Qiu, Xuan; Zhang, Lei; Gao, Yuan; Xiu, Yun; Huang, Chunxia; Tang, Yong

2018-04-01

The effects of estrogen replacement therapy (ORT) on white matter and the myelin sheath ultrastructure in the white matter of middle-aged ovariectomized (OVX) rats were investigated in this study. Middle-aged rats were ovariectomized and divided into a placebo replacement (OVX + O) group and an estrogen replacement (OVX + E) group. Then, the Morris water maze, electron microscope techniques, and stereological methods were used to investigate the effects of ORT on spatial learning capacity, white matter volume and the myelin sheath ultrastructure in the white matter. We found that the spatial learning capacity of the OVX + E rats was significantly improved compared with that of the OVX + O rats. When compared with that of OVX + O rats, the total volume of the myelin sheaths in the white matter of the OVX + E rats was significantly increased by 27%, and the difference between the outer perimeter and inner perimeter of the myelin sheaths of the white matter in the OVX + E rats increased significantly by 12.6%. The myelinated fibers with mean diameters of 1.2-1.4 μm were significantly longer (46.1%) in the OVX + E rats; the difference between the mean diameter of myelinated fibers and the mean diameter of axons (0-0.4 μm) was significantly increased by 21.6% in the OVX + E rats. These results suggested that ORT had positive protective effects on the spatial learning ability and on the myelin sheath ultrastructure in the white matter of middle-aged OVX rats. © 2017 Wiley Periodicals, Inc.

The Effect of Rectus Sheath Block as a Supplement of General Anesthesia on Postoperative Analgesia in Adult Patient Undergoing Umbilical Hernia Repair.

PubMed

Kartalov, Andrijan; Jankulovski, Nikola; Kuzmanovska, Biljana; Zdravkovska, Milka; Shosholcheva, Mirjana; Tolevska, Marija; Naumovski, Filip; Srceva, Marija; Petrusheva, Aleksandra Panovska; Selmani, Rexhep; Sivevski, Atanas

2017-12-01

Ultrasound guided rectus sheath block can block the ventral rami of the 7th to 12th thoracolumbar nerves by injection of local anesthetic into the space between the rectus muscle and posterior rectus sheath. The aim of this randomized double-blind study was to evaluate the analgesic effect of the bilateral ultrasound guided rectus sheath block as supplement of general anesthesia on patents undergoing elective umbilical hernia repair. After the hospital ethics committee approval, 60 (ASA I-II) adult patients scheduled for umbilical hernia repair were included in this study. The group I (n=30) patents received only general anesthesia. In the group II (n = 30) patents after induction of general anesthesia received a bilateral ultrasound guided rectus sheath block with 40 ml of 0.25% bupivacaine. In this study we assessed demographic and clinical characteristics, pain score - VAS at rest at 2, 4, 6, 12 and 24 hours after operation and total analgesic consumption of morphine dose over 24-hours. There were statistically significant differences in VAS scores between the groups I and II at all postoperative time points - 2hr, 4 hr, 6 hr, 12 hr and 24 hr. (P < 0.00001). The cumulative 24 hours morphine consumption after the operation was significantly lower in the group II (mean = 3.73 ± 1. 41) than the group I (mean = 8.76 ± 2.41). This difference was statistically significant (p = 0.00076). The ultrasound guided rectus sheath block used for umbilical hernia repair could reduce postoperative pain scores and the amount of morphine consumption in 24 hours postoperative period.

Double polymer sheathed carbon nanotube supercapacitors show enhanced cycling stability

NASA Astrophysics Data System (ADS)

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

T-4G Simulator and T-4 Ground Training Devices in USAF Undergraduate Pilot Training.

ERIC Educational Resources Information Center

Woodruff, Robert R.; Smith, James F.

The objective of the project was to investigate the utility of using an A/F37A-T4G T-37 flight simulator within the context of Air Force undergraduate pilot training. Twenty-one subjects, selected from three undergraduate pilot training classes, were given contact flight training in a TP4G/EPT simulator before going to T-37 aircraft for further…

Engagement of Cytotoxic T Lymphocyte–associated Antigen 4 (CTLA-4) Induces Transforming Growth Factor β (TGF-β) Production by Murine CD4+ T Cells

PubMed Central

Chen, Wanjun; Jin, Wenwen; Wahl, Sharon M.

1998-01-01

Evidence indicates that cytotoxic T lymphocyte–associated antigen 4 (CTLA-4) may negatively regulate T cell activation, but the basis for the inhibitory effect remains unknown. We report here that cross-linking of CTLA-4 induces transforming growth factor β (TGF-β) production by murine CD4+ T cells. CD4+ T helper type 1 (Th1), Th2, and Th0 clones all secrete TGF-β after antibody cross-linking of CTLA-4, indicating that induction of TGF-β by CTLA-4 signaling represents a ubiquitous feature of murine CD4+ T cells. Stimulation of the CD3–T cell antigen receptor complex does not independently induce TGF-β, but is required for optimal CTLA-4–mediated TGF-β production. The consequences of cross-linking of CTLA-4, together with CD3 and CD28, include inhibition of T cell proliferation and interleukin (IL)-2 secretion, as well as suppression of both interferon γ (Th1) and IL-4 (Th2). Moreover, addition of anti–TGF-β partially reverses this T cell suppression. When CTLA-4 was cross-linked in T cell populations from TGF-β1 gene–deleted (TGF-β1−/−) mice, the T cell responses were only suppressed 38% compared with 95% in wild-type mice. Our data demonstrate that engagement of CTLA-4 leads to CD4+ T cell production of TGF-β, which, in part, contributes to the downregulation of T cell activation. CTLA-4, through TGF-β, may serve as a counterbalance for CD28 costimulation of IL-2 and CD4+ T cell activation. PMID:9815262

Experimental study on the fire protection properties of PVC sheath for old and new cables.

PubMed

Xie, Qiyuan; Zhang, Heping; Tong, Lin

2010-07-15

The objective of the present study is to analyze the fire protection properties of old and new cables through TG, FTIR and MCC experiments. The results show that the mass loss of old cable sheath is clearly larger than the new one when the temperature is higher than 550 K in air or nitrogen atmosphere. It suggests that the old cable sheath starts to pyrolyze generally at the same temperature based on the analysis of the onset temperatures of mass loss. The results also show that there is a main peak DTG for the old and new cable sheath under each condition. However, the main peak DTG of old cable sheath is larger than that of the new cable sheath, especially in air atmosphere. The FTIR experiments show that the HCl is released by the new cable later but more quickly than the old cable. The MCC experiments suggest that compared with the new one, the peak heat release rate is larger for the old cable. It illustrates that the old cable sheath generally pyrolyzes and combusts more strongly and completely than the new one. Namely, the fire protection properties of the old cable in old buildings are relatively weak. 2010 Elsevier B.V. All rights reserved.

Assessing the permeability of the rat sciatic nerve epineural sheath against compounds with local anesthetic activity: an ex vivo electrophysiological study.

PubMed

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.

Fixation Strength of Polyetheretherketone Sheath-and-Bullet Device for Soft Tissue Repair in the Foot and Ankle.

PubMed

Christensen, Jay; Fischer, Brian; Nute, Michael; Rizza, Robert

Tendon transfers are often performed in the foot and ankle. Recently, interference screws have been a popular choice owing to their ease of use and fixation strength. Considering the benefits, one disadvantage of such devices is laceration of the soft tissues by the implant threads during placement that potentially weaken the structural integrity of the grafts. A shape memory polyetheretherketone bullet-in-sheath tenodesis device uses circumferential compression, eliminating potential damage from thread rotation and maintaining the soft tissue orientation of the graft. The aim of this study was to determine the pullout strength and failure mode for this device in both a synthetic bone analogue and porcine bone models. Thirteen mature bovine extensor tendons were secured into ten 4.0 × 4.0 × 4.0-cm cubes of 15-pound per cubic foot solid rigid polyurethane foam bone analogue models or 3 porcine femoral condyles using the 5 × 20-mm polyetheretherketone soft tissue anchor. The bullet-in-sheath device demonstrated a mean pullout of 280.84 N in the bone analog models and 419.47 N in the porcine bone models. (p = .001). The bullet-in-sheath design preserved the integrity of the tendon graft, and none of the implants dislodged from their original position. Copyright © 2017 The American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Abdominal foreign body: late presentation as a rectus sheath abscess.

PubMed

Noushif, M; Sivaprasad, S; Prashanth, A

2011-05-01

Intra-abdominal ingested foreign bodies are usually an incidental finding, typically encountered in mentally challenged patients. We present the case of a 65-year-old mentally sound woman who presented with recurrent abdominal pain and a lump in the hypogastrium. Evaluation revealed a rectus sheath abscess extending to the peritoneum, with a foreign body in situ. On enquiry, the patient revealed that she had accidentally ingested a tailoring needle 17 years ago. This case illustrates an unusual presentation of an ingested foreign body as a rectus sheath abscess after a long duration.

Combination L-T3 and L-T4 therapy for hypothyroidism.

PubMed

Wartofsky, Leonard

2013-10-01

Because of the longstanding controversy regarding whether hypothyroid patients can be optimally replaced by treatment with levothyroxine (L-T4) alone, numerous studies have addressed potential benefits of combined therapy of triiodothyronine (T3) with L-T4. Results of these studies have failed to support a potential benefit of combined therapy. A strong argument for the addition of L-T3 to L-T4 monotherapy has been lacking until recent genetic studies indicated a rationale for such therapy among a small fraction of the hypothyroid patient population. Interest in this issue has focused on the importance of the deiodinases in maintaining the euthyroid state and the role of genetic polymorphisms in the deiodinase genes that would affect thyroid hormone concentrations in both blood and tissues. One such polymorphism in the D2 gene, Thr92Ala, is associated with reduced T4 to T3 activation in skeletal muscle and thyroid, linked to obesity and alterations in thyroid-pituitary feedback, and in responses to thyroid hormone treatment. Although our professional organizations continue to recommend L-T4 alone for the treatment of hypothyroidism, the possibility of a D2 gene polymorphism should be considered in patients on L-T4 monotherapy who continue to complain of fatigue in spite of dosage achieving low normal serum thyroid stimulating hormone levels. A suggestive clue to the presence of this polymorphism could be a higher than normal free T4/free T3 ratio. Clinicians could consider adding T3 as a therapeutic trial in selected patients. Future well controlled clinical trials will be required to more fully resolve the controversy.

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

NASA Astrophysics Data System (ADS)

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.

Experimental Study of RF Sheaths due to Shear Alfv'en Waves in the LAPD

NASA Astrophysics Data System (ADS)

Martin, Michael; van Compernolle, Bart; Carter, Troy; Gekelman, Walter; Pribyl, Patrick; D'Ippolito, Daniel A.; Myra, James R.

2012-10-01

Ion cyclotron resonance frequency (ICRF) heating is an important tool in current fusion experiments and will be an essential part of the heating power in ITER. A current limitation of ICRF heating is impurity generation through the formation of radiofrequency (RF) sheaths, both near-field (at the antenna) and far-field (e.g. in the divertor region). Far-field sheaths are thought to be generated through the direct launch of or mode conversion to shear Alfv'en waves. Shear Alfv'en waves have an electric field component parallel to the background magnetic field near the wall that drives an RF sheath.footnotetextD. A. D'Ippolito and J. R. Myra, Phys. Plasmas 19, 034504 (2012) In this study we directly launch the shear Alfv'en wave and measure the plasma potential oscillations and DC potential in the bulk plasma of the LAPD using emissive and Langmuir probes. Measured changes in the DC plasma potential can serve as an indirect measurement of the formation of an RF sheath because of rectification. These measurements will be useful in guiding future experiments to measure the plasma potential profile inside RF sheaths as part of an ongoing campaign.

Far-Field RF Sheaths due to Shear Alfvén Waves in the LAPD

NASA Astrophysics Data System (ADS)

Martin, Michael; van Compernolle, Bart; Gekelman, Walter; Pribyl, Pat; Carter, Troy; D'Ippolito, Daniel A.; Myra, James R.

2013-10-01

Ion cyclotron resonance heating (ICRH) is an important tool in current fusion experiments and will be an essential heating component in ITER. ICRH could be limited by deleterious effects due to the formation of radio frequency (RF) sheaths in the near-field (at the antenna) and in the far-field (e.g. in the divertor region). Far-field sheaths are thought to be caused by the direct launch of or mode conversion to a shear Alfvén wave with an electric field component parallel to the background magnetic field at the wall. In this experiment a limiter plate was inserted into a cylindrical plasma in the LAPD (ne ~ 1010-11 cm-3, Te ~ 5 eV, B0 = 1.2 kG) and RF sheaths were created by directly launching the shear Alfven wave. Plasma potential measurements were made with an emissive probe. DC plasma potential rectification was observed along field lines connected to the plate, serving as an indirect measure of RF sheath formation. 2-D maps of plasma properties and rectified plasma potential will be presented. This research is part of an ongoing campaign to study the formation and structure of RF sheaths.

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

NASA Astrophysics Data System (ADS)

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.

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

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

Stamate, Eugen, E-mail: eust@dtu.dk; Venture Business Laboratory, Nagoya University, C3-1, Chikusa-ku, Nagoya 464-8603; Yamaguchi, Masahito

2015-08-31

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 geometrical structure of the plasma-sheath-lens and plasma parameters. The positive and negative ion kinetics within the plasma-sheath-lens are investigated both experimentally and theoretically and a modal focusing ring is identified on the surface of disk electrodes. The focusing ring is very sensitive to the sheath thickness and can be used to monitor very small changes in plasma parameters. Three dimensional simulationsmore » are found to be in very good agreement with experiments.« less

Differential Protein Composition and Gene Expression in Leaf Mesophyll Cells and Bundle Sheath Cells of the C(4) Plant Digitaria sanguinalis (L.) Scop.

PubMed

Potter, J W; Black, C C

1982-08-01

The distribution and molecular weights of cellular proteins in soluble and membrane-associated locations were analyzed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Coomassie blue staining of leaf (Digitaria sanguinalis L. Scop.) extracts and isolated cell extracts. Leaf polypeptides also were pulse-labeled, followed by isolation of the labeled leaf cell types and analysis of the newly synthesized polypeptides in each cell type by electrophoresis and fluorography.Comparison of the electrophoretic patterns of crabgrass whole leaf polypeptides with isolated cell-type polypeptides indicated a difference in protein distribution patterns for the two cell types. The mesophyll cells exhibited a greater allocation of total cellular protein into membrane-associated proteins relative to soluble proteins. In contrast, the bundle sheath cells exhibited a higher percentage of total cellular protein in soluble proteins. Phosphoenolpyruvate carboxylase was the major soluble protein in the mesophyll cell and ribulose bisphosphate carboxylase was the major soluble protein in the bundle sheath cell. The majority of in vivo(35)S-pulse-labeled proteins synthesized by the two crabgrass cell types corresponded in molecular weight to the proteins present in the cell types which were detected by conventional staining techniques. The bundle sheath cell and mesophyll cell fluorograph profiles each had 15 major (35)S-labeled proteins. The major incorporation of (35)S by bundle sheath cells was into products which co-electrophoresed with the large and small subunits of ribulose bisphosphate carboxylase. In contrast, a major (35)S-labeled product in mesophyll cell extracts co-electrophoresed with the subunit of phosphoenolpyruvate carboxylase. Both cell types exhibited equivalent in vivo labeling of a polypeptide with one- and two-dimensional electrophoretic behavior similar to the major apoprotein of the light-harvesting chlorophyll a/b protein. Results from the use of

Aerodynamics of an Axisymmetric Missile Concept Having Cruciform Strakes and In-Line Tail Fins From Mach 0.60 to 4.63, Supplement

NASA Technical Reports Server (NTRS)

Allen, Jerry M.

2005-01-01

An experimental study has been performed to develop a large force and moment aerodynamic data set on a slender axisymmetric missile configuration having cruciform strakes and in-line control tail fins. The data include six-component balance measurements of the configuration aerodynamics and three-component measurements on all four tail fins. The test variables include angle of attack, roll angle, Mach number, model buildup, strake length, nose size, and tail fin deflection angles to provide pitch, yaw, and roll control. Test Mach numbers ranged from 0.60 to 4.63. The entire data set is presented on a CD-ROM that is attached to this paper. The CD-ROM also includes extensive plots of both the six-component configuration data and the three-component tail fin data. Selected samples of these plots are presented in this paper to illustrate the features of the data and to investigate the effects of the test variables.

Predicting arsenic concentrations in porewaters of buried uranium mill tailings

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

Langmuir, D.; Mahoney, J.; MacDonald, A.

The proposed JEB Tailings Management Facility (TMF) to be emplaced below the groundwater table in northern Saskatchewan, Canada, will contain uranium mill tailings from McClean Lake, Midwest and Cigar Lake ore bodies, which are high in arsenic (up to 10%) and nickel (up to 5%). A serious concern is the possibility that high arsenic and nickel concentrations may be released from the buried tailings, contaminating adjacent groundwaters and a nearby lake. Laboratory tests and geochemical modeling were performed to examine ways to reduce the arsenic and nickel concentrations in TMF porewaters so as to minimize such contamination from tailings buriedmore » for 50 years and longer. The tests were designed to mimic conditions in the mill neutralization circuit (3 hr tests at 25 C), and in the TMF after burial (5--49 day aging tests). The aging tests were run at 50, 25 and 4 C (the temperature in the TMF). In order to optimize the removal of arsenic by adsorption and precipitation, ferric sulfate was added to tailings raffinates having Fe/As ratios of less than 3--5. The acid raffinates were then neutralized by addition of slaked lime to nominal pH values of 7, 8, or 9. Analysis and modeling of the test results showed that with slaked lime addition to acid tailings raffinates, relatively amorphous scorodite (ferric arsenate) precipitates near pH 1, and is the dominant form of arsenate in slake limed tailings solids except those high in Ni and As and low in Fe, in which cabrerite-annabergite (Ni, Mg, Fe(II) arsenate) may also precipitate near pH 5--6. In addition to the arsenate precipitates, smaller amounts of arsenate are also adsorbed onto tailings solids. The aging tests showed that after burial of the tailings, arsenic concentrations may increase with time from the breakdown of the arsenate phases (chiefly scorodite). However, the tests indicate that the rate of change decreases and approaches zero after 72 hrs at 25 C, and may equal zero at all times in the TMF at 4

Sheath formation in low-pressure discharges, the Bohm criterion and the consequences of collisions

NASA Astrophysics Data System (ADS)

Valentini, H.-B.; Kaiser, D.

2014-02-01

The space charge density in low-pressure discharges results from the generation of charged particles, the momentum transfer from these particles to the neutral gas and the electric field. A simplified model is used to treat this process analytically and numerically across the whole plasma. The effect of the electric field alone can cause the formation of the space charge sheath if the ion drift velocity υi to the wall exceeds the modified Bohm velocity υC = υB × (ni/ne)1/2, where υB is the Bohm velocity and ni and ne are the number densities of the ions and the electrons, respectively. However, a domain with υi ⩾ υC can occur only if the effect of collisions is weak. This domain is very narrow and does not come up to the wall. Limits of the electric field strength determining the sheath formation are given. It is shown that the electric field strength cannot be set equal to zero at υi = υB or υC under collisional conditions. The sheath extends from the region near the wall towards the centre and a result of that is to lower υi with respect to υB as the collisionality rises. These results are used to take into consideration various sheath criteria. The Bohm criterion takes into account the effect of the electric field only and reveals a well-defined sheath edge at υi = υB. This criterion remains a useful approximation of the sheath edge in almost collisionless plasmas as well. Under collisional conditions the definition of the sheath edge becomes more difficult and a little arbitrary. This paper takes into account new sheath criteria modified for the case of finite collisionality. The divergence between the densities of the ions and the electrons, the gradients of the space charge density and of the generalized Bohm speed υC are studied as functions of υi or the distance from the wall. These criteria are compared with the collisionally modified Bohm criteria proposed by Godyak (1982 Phys. Lett. A 89 80), Valentini (1996 Phys. Plasmas 3 1459), Chen

Speciation and characterization of arsenic in Ketza River mine tailings using X-ray absorption spectroscopy.

PubMed

Paktunc, Dogan; Foster, Andrea; Laflamme, Gilles

2003-05-15

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A for the exposed tailings and 3.33-3.35 A for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentate-binuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

Speciation and characterization of arsenic in Ketza River mine tailings using x-ray absorption spectroscopy

USGS Publications Warehouse

Paktunc, D.; Foster, A.; Laflamme, G.

2003-01-01

Ketza River mine tailings deposited underwater and those exposed near the tailings impoundment contain approximately 4 wt % As. Column-leaching tests indicated the potential for high As releases from the tailings. The tailings are composed dominantly of iron oxyhydroxides, quartz, calcite, dolomite, muscovite, ferric arsenates, and calcium-iron arsenates. Arsenopyrite and pyrite are trace constituents. Chemical compositions of iron oxyhydroxide and arsenate minerals are highly variable. The XANES spectra indicate that arsenic occurs as As(V) in tailings, but air-drying prior to analysis may have oxidized lower-valent As. The EXAFS spectra indicate As-Fe distances of 3.35-3.36 A?? for the exposed tailings and 3.33-3.35 A?? for the saturated tailings with coordination numbers of 0.96-1.11 and 0.46-0.64, respectively. The As-Ca interatomic distances ranging from 4.15 to 4.18 A?? and the coordination numbers of 4.12-4.58 confirm the presence of calcium-iron arsenates in the tailings. These results suggest that ferric arsenates and inner-sphere corner sharing or bidentatebinuclear attachment of arsenate tetrahedra onto iron hydroxide octahedra are the dominant form of As in the tailings. EXAFS spectra indicate that the exposed tailings are richer in arsenate minerals whereas the saturated tailings are dominated by the iron oxyhydroxides, which could help explain the greater release of As from the exposed tailings during leaching tests. It is postulated that the dissolution of ferric arsenates during flow-through experiments caused the high As releases from both types of tailings. Arsenic tied to iron oxyhydroxides as adsorbed species are considered stable; however, iron oxyhydroxides having low Fe/As molar ratios may not be as stable. Continued As releases from the tailings are likely due to dissolution of both ferric and calcium-iron arsenates and desorption of As from high-As bearing iron oxyhydroxides during aging.

Semi-analytical model for a static sheath including a weakly collisional presheath

NASA Astrophysics Data System (ADS)

Shirafuji, Tatsuru; Denpoh, Kazuki

2018-06-01

A semi-analytical static sheath (SASS) model can provide a spatial potential profile on a biased surface with microstructures, which can be used for predicting ion trajectories on the surface. However, two- or three-dimensional SASS models require a search procedure for a sheath edge equipotential profile, at which ions have the Bohm velocity, as the starting positions for calculating ion trajectories. This procedure can be troublesome when surface microstructures have complex structures. This difficulty is due to the fact that the SASS model cannot handle a presheath region. In this work, we propose a modified SASS model that can handle a presheath region. By using the modified SASS model, ion trajectories can be calculated from edges with arbitrary geometry without searching for the equipotential profile corresponding to sheath edges.

Undernutrition and serum and urinary urea nitrogen of white-tailed deer during winter

USGS Publications Warehouse

DelGiudice, G.D.; Mech, L.D.; Seal, U.S.

1994-01-01

Direct, practical means of assessing undernutrition in deer (Odocoileus spp.) and other ungulates during winter are needed in areas of research and management. We examined the relationship between mass loss and serum urea nitrogen (SUN) and urinary urea nitrogen:creatinine (U:C) in captive white-tailed deer (O. virginianus). During 4 February-5 May 1988, we maintained 7 adult white-tailed deer on various feeding regimes to simulate natural nutritional restriction during winter. Mass loss was greater (P = 0.037) in deer (17.0-32.2%) fed restricted amounts of a low protein low energy diet versus control deer (7.0-17.4%) fed the same diet ad libitum. Serum triiodothyronine (T3) concentrations did not differ (P = 0.191) between groups, but declined (P = 0.001) as nutrition declined. Slopes of percent mass lossSUN and urinary U:C relationships were positive (P = 0.008 and 0.055) in 7 and 6 deer, respectively. Mean U:C was directly related (r2 = 0.52, P = 0.040) to mean cumulative mass loss, whereas mean SUN was not (r2 = 0.29, P = 0.125). Data presented support the potential of urinary U:C as an index of winter nutritional condition of white-tailed deer; however, additional research is required to provide a complete understanding of this index's utility under field conditions.

Dynamics of current sheath in a hollow electrode Z-pinch discharge using slug model

NASA Astrophysics Data System (ADS)

Abd Al-Halim, Mohamed A.; Afify, M. S.

2017-03-01

The hollow electrode Z-pinch (HEZP) experiment is a new construction for the electromagnetic propulsion application in which the plasma is formed by the discharge between a plate and ring electrodes through which the plasma is propelled. The experimental results for 8 kV charging voltage shows that the peak discharge current is about 109 kA, which is in good agreement with the value obtained from the simulation in the slug model that simulates the sheath dynamics in the HEZP. The fitting of the discharge current from the slug model indicates that the total system inductance is 238 nH which is relatively a high static inductance accompanied with a deeper pinch depth indicating that the fitted anomalous resistance would be about 95 mΩ. The current and mass factors vary with the changing the gas pressure and the charging voltage. The current factor is between 0.4 and 0.5 on average which is relatively low value. The mass factor decreases by increasing the gas pressure indicating that the sheath is heavy to be driven by the magnetic pressure, which is also indicated from the decreases of the drive factor, hence the radial sheath velocity decreases. The plasma inductance and temperature increase with the increase of the drive factor while the minimum pinch radius decreases.

Influence of the axial magnetic field on sheath development after current zero in a vacuum circuit breaker

NASA Astrophysics Data System (ADS)

Chen, Yi; Yang, Fei; Sun, Hao; Wu, Yi; Niu, Chunping; Rong, Mingzhe

2017-06-01

After current zero, which is the moment when the vacuum circuit breaker interrupts a vacuum arc, sheath development is the first process in the dielectric recovery process. An axial magnetic field (AMF) is widely used in the vacuum circuit breaker when the high-current vacuum arc is interrupted. Therefore, it is very important to study the influence of different AMF amplitudes on the sheath development. The objective of this paper is to study the influence of different AMF amplitudes on the sheath development from a micro perspective. Thus, the particle in cell-Monte Carlo collisions (PIC-MCC) method was adopted to develop the sheath development model. We compared the simulation results with the experimental results and then validated the simulation. We also obtained the speed of the sheath development and the energy density of the ions under different AMF amplitudes. The results showed that the larger the AMF amplitudes are, the faster the sheath develops and the lower the ion energy density is, meaning the breakdown is correspondingly more difficult.

Endobronchial ultrasonography using a guide sheath technique for diagnosis of peripheral pulmonary lesions

PubMed Central

Zhang, Lei; Wu, Hongxu; Wang, Guiqi

2017-01-01

Endobronchial ultrasonography using a guide sheath (EBUS-GS) is a novel method used for collecting peripheral pulmonary lesion (PPL) samples. EBUS-GS is performed by introducing a guide sheath-covered miniprobe into the target bronchus and then withdrawing the miniprobe after lesion detection, leaving the guide sheath in situ as a working channel for obtaining lesion samples. EBUS-GS can improve PPL diagnosis rates and be used for obtaining specimens for molecular analysis. In this review, we discuss the clinical applications of EBUS-GS, the factors that affect its diagnostic sensitivity, and potential complications. We also compare EBUS-GS with other available diagnostic techniques and discuss the strengths and limitations of this method. PMID:29063872

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

NASA Astrophysics Data System (ADS)

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

Composite pheochromocytoma with a malignant peripheral nerve sheath tumor: Case report and review of the literature.

PubMed

Namekawa, Takeshi; Utsumi, Takanobu; Imamoto, Takashi; Kawamura, Koji; Oide, Takashi; Tanaka, Tomoaki; Nihei, Naoki; Suzuki, Hiroyoshi; Nakatani, Yukio; Ichikawa, Tomohiko

2016-07-01

Adrenal tumors with more than one cellular component are uncommon. Furthermore, an adrenal tumor composed of a pheochromocytoma and a malignant peripheral nerve sheath tumor is extremely rare. A composite pheochromocytoma with malignant peripheral nerve sheath tumor in a 42-year-old man is reported here. After adequate preoperative control, left adrenalectomy was performed simultaneously with resection of the ipsilateral kidney for spontaneous rupture of the left adrenal tumor. Pathological findings demonstrated pheochromocytoma and malignant peripheral nerve sheath tumor in a ruptured adrenal tumor. To date, there have been only four reported cases of composite pheochromocytoma with malignant peripheral nerve sheath tumor, so the present case is only the fifth case in the world. Despite the very poor prognosis of patients with pheochromocytoma and malignant peripheral nerve sheath tumors reported in the literature, the patient remains well without evidence of recurrence or new metastatic lesions at 36 months postoperatively. Copyright © 2012. Published by Elsevier Taiwan.

Spontaneous Rectus Sheath Hematoma

PubMed Central

Alla, Venkata M; Karnam, Showri M.; Kaushik, Manu; Porter, Joann

2010-01-01

Abdominal wall pathology is a frequently overlooked cause of acute abdomen. Increasing use of antiplatelet and anticoagulant therapies has led to an increase in the incidence of spontaneous rectus sheath hematoma (RSH). A high index of suspicion is needed for diagnosis as it can closely mimic other causes of acute abdomen. Herein, we report a case of RSH presenting with abdominal pain in which there was a significant delay in diagnosis. We wish to highlight the need to increase awareness among primary and emergency physicians about considering RSH in the initial differential diagnoses of abdominal pain. PMID:20411082

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

NASA Astrophysics Data System (ADS)

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.

Bacteriophage Tail-Tube Assembly Studied by Proton-Detected 4D Solid-State NMR

DOE PAGES

Zinke, Maximilian; Fricke, Pascal; Samson, Camille; ...

2017-07-07

Obtaining unambiguous resonance assignments remains a major bottleneck in solid-state NMR studies of protein structure and dynamics. Particularly for supramolecular assemblies with large subunits (>150 residues), the analysis of crowded spectral data presents a challenge, even if three-dimensional (3D) spectra are used. Here, we present a proton-detected 4D solid-state NMR assignment procedure that is tailored for large assemblies. The key to recording 4D spectra with three indirect carbon or nitrogen dimensions with their inherently large chemical shift dispersion lies in the use of sparse non-uniform sampling (as low as 2 %). As a proof of principle, we acquired 4D (H)COCANH,more » (H)CACONH, and (H)CBCANH spectra of the 20 kDa bacteriophage tail-tube protein gp17.1 in a total time of two and a half weeks. These spectra were sufficient to obtain complete resonance assignments in a straightforward manner without use of previous solution NMR data.« less

Bacteriophage Tail-Tube Assembly Studied by Proton-Detected 4D Solid-State NMR

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

Zinke, Maximilian; Fricke, Pascal; Samson, Camille

Obtaining unambiguous resonance assignments remains a major bottleneck in solid-state NMR studies of protein structure and dynamics. Particularly for supramolecular assemblies with large subunits (>150 residues), the analysis of crowded spectral data presents a challenge, even if three-dimensional (3D) spectra are used. Here, we present a proton-detected 4D solid-state NMR assignment procedure that is tailored for large assemblies. The key to recording 4D spectra with three indirect carbon or nitrogen dimensions with their inherently large chemical shift dispersion lies in the use of sparse non-uniform sampling (as low as 2 %). As a proof of principle, we acquired 4D (H)COCANH,more » (H)CACONH, and (H)CBCANH spectra of the 20 kDa bacteriophage tail-tube protein gp17.1 in a total time of two and a half weeks. These spectra were sufficient to obtain complete resonance assignments in a straightforward manner without use of previous solution NMR data.« less

Ultrasound-guided steroid tendon sheath injections in juvenile idiopathic arthritis: a 10-year single-center retrospective study.

PubMed

Peters, Shannon E; Laxer, Ronald M; Connolly, Bairbre L; Parra, Dimitri A

2017-04-11

The aims of this study were to: (a) Identify tendon sheaths most commonly treated with steroid injections in a pediatric patient population with Juvenile Idiopathic Arthritis (JIA); (b) Describe technical aspects of the procedure; (c) Characterize sonographic appearance of tenosynovitis in JIA; (d) Assess agreement between clinical request and sites injected. This was a 10 year single-center retrospective study (May 2006-April 2016) of patients with JIA referred by Rheumatology for ultrasound-guided tendon sheath injections. Patient demographics, clinical referral information, sonographic appearance of the tendon sheaths and technical aspects of the procedure were analyzed. There were 308 procedures of 244 patients (75% female, mean age 9.6 years) who underwent a total of 926 tendon sheath injections. Ankle tendons were most commonly injected (84.9%), specifically the tendon sheaths of tibialis posterior (22.3%), peroneus longus (20%) and brevis (19.7%). The majority of treated sites (91.9%) showed peritendinous fluid and sheath thickening on ultrasound. There were 2 minor intra-procedure complications without sequelae. A good agreement between clinical request and sites injected was observed. Ultrasound-guided tendon sheath injections with steroids are used frequently to treat patients with JIA. It is a safe intervention with a high technical success rate. The ankle region, specifically the medial compartment, is the site most commonly injected in this group of patients. The most common sonographic finding is peritendinous fluid and sheath thickening. These findings might assist clinicians and radiologists to characterize and more effectively manage tenosynovitis in patients with JIA.

A 70 Kiloparsec X-Ray Tail in the Cluster A3627

NASA Technical Reports Server (NTRS)

Sun, M.; Jones, C.; Forman, W.; Nulsen, P. E. J.; Donahue, M.; Voit, G. M.

2006-01-01

We present the discovery of a 70 kpc X-ray tail behind the small late-type galaxy ESO 137-001, in the nearby, hot (T=6.5 keV) merging cluster A3627, from both Chandra and XMM-Newton observations. The tail has a length-to-width ratio of approx. 10. It is luminous (L(0.5-2keV) approx 1041 ergs/s), with a temperature of approx. 0.7 keV and an X-ray gas mass of approx 10(exp 9) solar masses (approx 10% of the galaxy's stellar mass). We interpret this tail as the stripped interstellar medium of ESO 137-001 mixed with the hot cluster medium, with this blue galaxy being converted into a gas-poor galaxy. Three X-ray point sources are detected in the axis of the tail, which may imply active star formation there. The straightness and narrowness of the tail also imply that the turbulence in the intracluster medium is not strong on scales of 20-70 kpc.

A Combinatorial H4 Tail Library to Explore the Histone Code

PubMed Central

Garske, Adam L.; Craciun, Gheorghe; Denu, John M.

2008-01-01

Histone modifications modulate chromatin structure and function. A posttranslational modification-randomized, combinatorial library based on the first twenty-one residues of histone H4 was designed for systematic examination of proteins that interpret a histone code. The 800-member library represented all permutations of most known modifications within the N-terminal tail of histone H4. To determine its utility in a protein-binding assay, the on-bead library was screened with an antibody directed against phosphoserine 1 of H4. Among the hits, 59/60 sequences were phosphorylated at S1, while 30/30 of those selected from the non-hits were unphosphorylated. A 512-member version of the library was then used to determine the binding specificity of the double tudor domain of hJMJD2A, a histone demethylase involved in transcriptional repression. Global linear least squares fitting of modifications from the identified peptides (40 hits and 34 non-hits) indicated that methylation of K20 was the primary determinant for binding, but that phosphorylation/acetylation on neighboring sites attenuated the interaction. To validate the on-bead screen, isothermal titration calorimetry was performed with thirteen H4 peptides. Dissociation constants ranged from 1 mM - 1μM and corroborated the screening results. The general approach should be useful for probing the specificity of any histone-binding protein. PMID:18616348

Dynamics of magnetized plasma sheaths around a trench

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

Hatami, M. M., E-mail: m-hatami@kntu.ac.ir

2016-08-15

Considering a magnetized plasma sheath, the temporal evolution of the ion properties (the incident ion flux, the ion impact angle, and the incident ion dose) around a rectangular trench is studied numerically. Our results show that the ion flux along the bottom surface greatly reduces in the presence of magnetic field and its uniformity improves, but the magnetic field does not considerably affect the ion flux along the sidewall. In addition, the thickness of the plasma sheath increases by increasing the magnetic field while its conformality to the target surface reduces faster. Moreover, it is shown that any increase inmore » the magnitude (inclination angle) of the magnetic field causes a decrease (an increase) in the angle of incidence of ions on the bottom and sidewall surfaces. Furthermore, in the presence of magnetic field, the ions strike nearly normal to the surface of the bottom while they become less oblique along the sidewall surface. In addition, contrary to the corners of the trench, it is found that the magnetic field greatly affects the incident ion dose at the center of the trench surfaces. Also, it is shown that the incident ion dose along the sidewall is the highest near the center of the sidewall in both magnetized and magnetic-free cases. However, uniformity of the incident ion dose along the sidewall is better than that along the bottom in both magnetized and unmagnetized plasma sheath.« less

Synthesis and structure of the extended phosphazane ligand [(1,4-C6H4){N(μ-PN(t)Bu)2N(t)Bu}2](4).

PubMed

Sevilla, Raquel; Less, Robert J; García-Rodríguez, Raúl; Bond, Andrew D; Wright, Dominic S

2016-02-07

The reaction of the phenylene-bridged precursor (1,4-C6H4)[N(PCl2)2]2 with (t)BuNH2 in the presence of Et3N gives the new ligand precursor (1,4-C6H4)[N(μ-N(t)Bu)2(PNH(t)Bu)2]2, deprotonation of which with Bu2Mg gives the novel tetraanion [(1,4-C6H4){N(μ-N(t)Bu)2(PN(t)Bu)2}2](4-).

30 CFR 75.1314 - Sheathed explosive units.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Sheathed explosive units. 75.1314 Section 75.1314 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND... damaged or deteriorated. (d) Except in anthracite mines, rock dust shall be applied to the roof, ribs and...

Sheath expansion and plasma dynamics in the presence of electrode evaporation: Application to a vacuum circuit breaker

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

Sarrailh, P.; LAPLACE, CNRS, F-31062 Toulouse; Schneider Electric, Centre de Recherche 38 TEC, 38050 Grenoble Cedex 09

2009-09-01

During the postarc dielectric recovery phase in a vacuum circuit breaker, a cathode sheath forms and expels the plasma from the electrode gap. The success or failure of current breaking depends on how efficiently the plasma is expelled from the electrode gap. The sheath expansion in the postarc phase can be compared to sheath expansion in plasma immersion ion implantation except that collisions between charged particles and atoms generated by electrode evaporation may become important in a vacuum circuit breaker. In this paper, we show that electrode evaporation plays a significant role in the dynamics of the sheath expansion inmore » this context not only because charged particle transport is no longer collisionless but also because the neutral flow due to evaporation and temperature gradients may push the plasma toward one of the electrodes. Using a hybrid model of the nonequilibrium postarc plasma and cathode sheath coupled with a direct simulation Monte Carlo method to describe collisions between heavy species, we present a parametric study of the sheath and plasma dynamics and of the time needed for the sheath to expel the plasma from the gap for different values of plasma density and electrode temperatures at the beginning of the postarc phase. This work constitutes a preliminary step toward understanding and quantifying the risk of current breaking failure of a vacuum arc.« less

Sheath expansion and plasma dynamics in the presence of electrode evaporation: Application to a vacuum circuit breaker

NASA Astrophysics Data System (ADS)

Sarrailh, P.; Garrigues, L.; Hagelaar, G. J. M.; Boeuf, J. P.; Sandolache, G.; Rowe, S.

2009-09-01

During the postarc dielectric recovery phase in a vacuum circuit breaker, a cathode sheath forms and expels the plasma from the electrode gap. The success or failure of current breaking depends on how efficiently the plasma is expelled from the electrode gap. The sheath expansion in the postarc phase can be compared to sheath expansion in plasma immersion ion implantation except that collisions between charged particles and atoms generated by electrode evaporation may become important in a vacuum circuit breaker. In this paper, we show that electrode evaporation plays a significant role in the dynamics of the sheath expansion in this context not only because charged particle transport is no longer collisionless but also because the neutral flow due to evaporation and temperature gradients may push the plasma toward one of the electrodes. Using a hybrid model of the nonequilibrium postarc plasma and cathode sheath coupled with a direct simulation Monte Carlo method to describe collisions between heavy species, we present a parametric study of the sheath and plasma dynamics and of the time needed for the sheath to expel the plasma from the gap for different values of plasma density and electrode temperatures at the beginning of the postarc phase. This work constitutes a preliminary step toward understanding and quantifying the risk of current breaking failure of a vacuum arc.

Transporters for Antiretroviral Drugs in Colorectal CD4+ T Cells and Circulating α4β7 Integrin CD4+ T Cells: Implications for HIV Microbicides.

PubMed

Mukhopadhya, Indrani; Murray, Graeme I; Duncan, Linda; Yuecel, Raif; Shattock, Robin; Kelly, Charles; Iannelli, Francesco; Pozzi, Gianni; El-Omar, Emad M; Hold, Georgina L; Hijazi, Karolin

2016-09-06

CD4+ T lymphocytes in the colorectal mucosa are key in HIV-1 transmission and dissemination. As such they are also the primary target for antiretroviral (ARV)-based rectal microbicides for pre-exposure prophylaxis. Drug transporters expressed in mucosal CD4+ T cells determine ARV distribution across the cell membrane and, most likely, efficacy of microbicides. We describe transporters for antiretroviral drugs in colorectal mucosal CD4+ T lymphocytes and compare gene expression with circulating α4β7+CD4+ T cells, which traffic to the intestine and have been shown to be preferentially infected by HIV-1. Purified total CD4+ T cells were obtained from colorectal tissue and blood samples by magnetic separation. CD4+ T cells expressing α4β7 integrin were isolated by fluorescence-activated cell sorting from peripheral blood mononuclear cells of healthy volunteers. Expressions of 15 efflux and uptake drug transporter genes were quantified using Taqman qPCR assays. Expression of efflux transporters MRP3, MRP5, and BCRP and uptake transporter CNT2 were significantly higher in colorectal CD4+ T cells compared to circulating CD4+ T cells (p = 0.01-0.03). Conversely, circulating α4β7+CD4+ T cells demonstrated significantly higher expression of OATPD compared to colorectal CD4+ T cells (p = 0.001). To the best of our knowledge this is the first report of drug transporter gene expression in colorectal CD4+ and peripheral α4β7+CD4+ T cells. The qualitative and quantitative differences in drug transporter gene expression profiles between α4β7+CD4+ T cells and total mucosal CD4+ T cells may have significant implications for the efficacy of rectally delivered ARV-microbicides. Most notably, we have identified efflux drug transporters that could be targeted by selective inhibitors or beneficial drug-drug interactions to enhance intracellular accumulation of antiretroviral drugs.

Highly Stretchable Core-Sheath Fibers via Wet-Spinning for Wearable Strain Sensors.

PubMed

Tang, Zhenhua; Jia, Shuhai; Wang, Fei; Bian, Changsheng; Chen, Yuyu; Wang, Yonglin; Li, Bo

2018-02-21

Lightweight, stretchable, and wearable strain sensors have recently been widely studied for the development of health monitoring systems, human-machine interfaces, and wearable devices. Herein, highly stretchable polymer elastomer-wrapped carbon nanocomposite piezoresistive core-sheath fibers are successfully prepared using a facile and scalable one-step coaxial wet-spinning assembly approach. The carbon nanotube-polymeric composite core of the stretchable fiber is surrounded by an insulating sheath, similar to conventional cables, and shows excellent electrical conductivity with a low percolation threshold (0.74 vol %). The core-sheath elastic fibers are used as wearable strain sensors, exhibiting ultra-high stretchability (above 300%), excellent stability (>10 000 cycles), fast response, low hysteresis, and good washability. Furthermore, the piezoresistive core-sheath fiber possesses bending-insensitiveness and negligible torsion-sensitive properties, and the strain sensing performance of piezoresistive fibers maintains a high degree of stability under harsh conditions. On the basis of this high level of performance, the fiber-shaped strain sensor can accurately detect both subtle and large-scale human movements by embedding it in gloves and garments or by directly attaching it to the skin. The current results indicate that the proposed stretchable strain sensor has many potential applications in health monitoring, human-machine interfaces, soft robotics, and wearable electronics.

Prevention and Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

DTIC Science & Technology

2015-04-01

AWARD NUMBER: W81XWH-14-1-0073 TITLE: Prevention and Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath...Annual 3. DATES COVERED 1 Apr 2014 - 31 Mar 2015 4. TITLE AND SUBTITLE Prevention and Treatment of Neurofibromatosis Type 1- 5a. CONTRACT NUMBER...Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT The most common cause of death in Neurofibromatosis Type 1 (NF1) patients is

Synthesis and interface structures of zinc sulfide sheathed zinc-cadmium nanowire heterojunctions.

PubMed

Shen, Guozhen; Bando, Yoshio; Gao, Yihua; Golberg, Dmitri

2006-07-27

Zinc sulfide (ZnS) sheathed zinc (Zn)-cadmium (Cd) nanowire heterojunctions have been prepared by thermal evaporating of ZnS and CdS powders in a vertical induction furnace at 1200 degrees C. Studies found that both the Zn and Cd subnanowires, within a single nanoheterojunction, are single-crystallines with the growth directions perpendicular to the [210] plane, whereas the sheathed ZnS is polycrystalline with a thickness of ca. 5 nm. The Zn/Cd interface structure in the ZnS sheathed Zn-Cd nanowire heterojunctions was thoroughly experimentally studied by high-resolution transmission electron microscopy and theoretically studied using a near-coincidence site lattice (NCSL) concept. The results show that the Cd and Zn have a crystalline orientation relationship as [0001]Zn//[0001]Cd, (10(-)10)Zn//(10(-)10)Cd, (01(-)10)Zn//(01(-)10)Cd, and ((-)1100)Zn//((-)1100)Cd.

A Tale of Two Tails: Exploring Stellar Populations in the Tidal Tails of NGC 3256

NASA Astrophysics Data System (ADS)

Rodruck, Michael; Charlton, Jane C.; Konstantopoulos, Iraklis

2016-01-01

Galaxy interactions can inject material into the intergalactic medium via violent gravitational dynamics, often visualized in tidal tails. The composition of these tails has remained a mystery, as previous studies have focused on detecting tidal features, rather than the composite material itself. We have developed an observing program using deep, multiband imaging to probe the chaotic regions of tidal tails in search for an underlying stellar population. NGC 3256's twin tidal tails serve as a case study for this new technique. Our results show color values of u - g = 1.15 and r - i = 0.08 for the Western tail, and u - g = 1.33 and r - i = 0.22 for the Eastern tail, corresponding to discrepant ages between the tails of approximately 320 Myr and 785 Myr, respectively. With the interaction age of the system measured at 400 Myr, we find the stellar light in Western tail to be dominated by disrupted star clusters formed during and after the interaction, whereas the light from the Eastern tail is dominated by a 10 Gyr population originating from the host galaxies. We fit the Eastern tail color to a Mixed Stellar Population (MSP) model comprised 94% by mass of a 10 Gyr stellar population, and 6% of a 309 Myr population. We find 52% of the bolometric flux originating from this 10 Gyr population. We also detect a blue to red color gradient in each tail, running from galactic center to tail tip. In addition to tidal tail light, we detect 29 star cluster candidates (SCCs) in the Western tail and 19 in the Eastern, with mean ages of 282 Myr and 98 Myr respectively. Interestingly, we find an excess of very blue SCCs in the Eastern tail as compared to the Western tail, marking a recent, small episode of star formation.

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

NASA Technical Reports Server (NTRS)

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.

Effects of potassium iodide in concentrations of TSH, tT3 and tT4 in serum of subjects with sporotrichosis.

PubMed

Ramírez Soto, Max Carlos

2014-08-01

The saturated potassium iodide solution (SSKI) as treatment for sporotrichosis may cause hypothyroidism by suppressing the synthesis of thyroid hormones (tT3 and tT4 ) and the iodine excess could lead to thyrotoxicosis. Evaluating the changes in serum levels of TSH, tT3 and tT4 in euthyroid patients with sporotrichosis treated with SSKI. For the selection of euthyroid patients, TSH, tT3 and tT4 concentrations were measured for those adults and children diagnosed with sporotrichosis. Each paediatric patient was administered SSKI orally in increasing doses of 2-20 drops/3 times/day and 4-40 drops/3 times/day in adults. Serum concentrations of TSH, tT3 and tT4 were measured 20 days after started the treatment and 15 days posttreatment. Eight euthyroid patients aged between 2 to 65 years old were included. After 20 days of treatment, two suffered subclinical hypothyroidism, one developed subclinical hyperthyroidism, and one hyperthyroxinaemia euthyroid. At 15 days posttreatment only four patients were evaluated and all serum levels of TSH, tT3 and tT4 were normal. Some euthyroid patients with sporotrichosis can develop hyperthyroidism or subclinical iodine-induced hypothyroidism, during the administration of 3 or 6 g SSKI/day. © 2014 Blackwell Verlag GmbH.

Limited CD4+ T cell proliferation leads to preservation of CD4+ T cell counts in SIV-infected sooty mangabeys.

PubMed

Chan, Ming Liang; Petravic, Janka; Ortiz, Alexandra M; Engram, Jessica; Paiardini, Mirko; Cromer, Deborah; Silvestri, Guido; Davenport, Miles P

2010-12-22

Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections result in chronic virus replication and progressive depletion of CD4+ T cells, leading to immunodeficiency and death. In contrast, 'natural hosts' of SIV experience persistent infection with high virus replication but no severe CD4+ T cell depletion, and remain AIDS-free. One important difference between pathogenic and non-pathogenic infections is the level of activation and proliferation of CD4+ T cells. We analysed the relationship between CD4+ T cell number and proliferation in HIV, pathogenic SIV in macaques, and non-pathogenic SIV in sooty mangabeys (SMs) and mandrills. We found that CD4+ T cell proliferation was negatively correlated with CD4+ T cell number, suggesting that animals respond to the loss of CD4+ T cells by increasing the proliferation of remaining cells. However, the level of proliferation seen in pathogenic infections (SIV in rhesus macaques and HIV) was much greater than in non-pathogenic infections (SMs and mandrills). We then used a modelling approach to understand how the host proliferative response to CD4+ T cell depletion may impact the outcome of infection. This modelling demonstrates that the rapid proliferation of CD4+ T cells in humans and macaques associated with low CD4+ T cell levels can act to 'fuel the fire' of infection by providing more proliferating cells for infection. Natural host species, on the other hand, have limited proliferation of CD4+ T cells at low CD4+ T cell levels, which allows them to restrict the number of proliferating cells susceptible to infection.

MS4a4B, a CD20 homologue in T cells, inhibits T cell propagation by modulation of cell cycle.

PubMed

Xu, Hui; Yan, Yaping; Williams, Mark S; Carey, Gregory B; Yang, Jingxian; Li, Hongmei; Zhang, Guang-Xian; Rostami, Abdolmohamad

2010-11-01

MS4a4B, a CD20 homologue in T cells, is a novel member of the MS4A gene family in mice. The MS4A family includes CD20, FcεRIβ, HTm4 and at least 26 novel members that are characterized by their structural features: with four membrane-spanning domains, two extracellular domains and two cytoplasmic regions. CD20, FcεRIβ and HTm4 have been found to function in B cells, mast cells and hematopoietic cells respectively. However, little is known about the function of MS4a4B in T cell regulation. We demonstrate here that MS4a4B negatively regulates mouse T cell proliferation. MS4a4B is highly expressed in primary T cells, natural killer cells (NK) and some T cell lines. But its expression in all malignant T cells, including thymoma and T hybridoma tested, was silenced. Interestingly, its expression was regulated during T cell activation. Viral vector-driven overexpression of MS4a4B in primary T cells and EL4 thymoma cells reduced cell proliferation. In contrast, knockdown of MS4a4B accelerated T cell proliferation. Cell cycle analysis showed that MS4a4B regulated T cell proliferation by inhibiting entry of the cells into S-G2/M phase. MS4a4B-mediated inhibition of cell cycle was correlated with upregulation of Cdk inhibitory proteins and decreased levels of Cdk2 activity, subsequently leading to inhibition of cell cycle progression. Our data indicate that MS4a4B negatively regulates T cell proliferation. MS4a4B, therefore, may serve as a modulator in the negative-feedback regulatory loop of activated T cells.

Guts don't fly: Small digestive organs in obese Bar-tailed Godwits

USGS Publications Warehouse

Piersma, Theunis; Gill, Robert E.

1998-01-01

We documented fat loads and abdominal organ sizes of Bar-tailed Godwits (Limosa lapponica baueri) that died after colliding against a radar dome on the Alaska Peninsula, most likely just after takeoff on a trans-Pacific flight of 11,000 km, and of birds of the same subspecies just before northward departure from New Zealand. We compared these data with data on body composition of godwits of the smaller lapponica subspecies obtained during a northward stopover in The Netherlands. As a consequence of high amounts of subcutaneous and intraperitoneal fat, and very small fat-free mass, Bar-tailed Godwits from Alaska had relative fat loads that are among the highest ever recorded in birds (ca. 55% of fresh body mass). Compared with northbound godwits from New Zealand, the Alaskan birds had very small gizzards, livers, kidneys, and guts. This suggests that upon departure, long-distance migrants dispense with parts of their "metabolic machinery" that are not directly necessary during flight, and rebuild these organs upon arrival at the migratory destination.

14. Credit PED. Downstream elevation, near completion, showing tail race ...

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

14. Credit PED. Downstream elevation, near completion, showing tail race and trestle used to carry excavated rock and construction materials across tail race. Photo c. 1909. - Dam No. 4 Hydroelectric Plant, Potomac River, Martinsburg, Berkeley County, WV

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

PubMed

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.

Transgenic expression of Map3k4 rescues T-associated sex reversal (Tas) in mice

PubMed Central

Warr, Nick; Siggers, Pam; Carré, Gwenn-Aël; Bogani, Debora; Brixey, Rachel; Akiyoshi, Mika; Tachibana, Makoto; Teboul, Lydia; Wells, Sara; Sanderson, Jeremy; Greenfield, Andy

2014-01-01

Disorders of sex development in the human population range in severity from mild genital defects to gonadal sex reversal. XY female development has been associated with heterozygous mutations in several genes, including SOX9, WT1 and MAP3K1. In contrast, XY sex reversal in mice usually requires complete absence of testis-determining gene products. One exception to this involves T-associated sex reversal (Tas), a phenomenon characterized by the formation of ovotestes or ovaries in XY mice hemizygous for the hairpin-tail (Thp) or T-Orleans (TOrl) deletions on proximal mouse chromosome 17. We recently reported that mice heterozygous for a null allele of Map3k4, which resides in the Thp deletion, exhibit XY ovotestis development and occasional gonadal sex reversal on the sensitized C57BL/6J-YAKR (B6-YAKR) genetic background, reminiscent of the Tas phenotype. However, these experiments did not exclude the possibility that loss of other loci in the Thp deletion, or other effects of the deletion itself, might contribute to Tas. Here, we show that disruption to Sry expression underlies XY gonadal defects in B6-YAKR embryos harbouring the Thp deletion and that a functional Map3k4 bacterial artificial chromosome rescues these abnormalities by re-establishing a normal Sry expression profile. These data demonstrate that Map3k4 haploinsufficiency is the cause of T-associated sex reversal and that levels of this signalling molecule are a major determinant of the expression profile of Sry. PMID:24452333

Specificity of interactions among the DNA-packaging machine components of T4-related bacteriophages.

PubMed

Gao, Song; Rao, Venigalla B

2011-02-04

Tailed bacteriophages use powerful molecular motors to package the viral genome into a preformed capsid. Packaging at a rate of up to ∼2000 bp/s and generating a power density twice that of an automobile engine, the phage T4 motor is the fastest and most powerful reported to date. Central to DNA packaging are dynamic interactions among the packaging components, capsid (gp23), portal (gp20), motor (gp17, large "terminase"), and regulator (gp16, small terminase), leading to precise orchestration of the packaging process, but the mechanisms are poorly understood. Here we analyzed the interactions between small and large terminases of T4-related phages. Our results show that the gp17 packaging ATPase is maximally stimulated by homologous, but not heterologous, gp16. Multiple interaction sites are identified in both gp16 and gp17. The specificity determinants in gp16 are clustered in the diverged N- and C-terminal domains (regions I-III). Swapping of diverged region(s), such as replacing C-terminal RB49 region III with that of T4, switched ATPase stimulation specificity. Two specificity regions, amino acids 37-52 and 290-315, are identified in or near the gp17-ATPase "transmission" subdomain II. gp16 binding at these sites might cause a conformational change positioning the ATPase-coupling residues into the catalytic pocket, triggering ATP hydrolysis. These results lead to a model in which multiple weak interactions between motor and regulator allow dynamic assembly and disassembly of various packaging complexes, depending on the functional state of the packaging machine. This might be a general mechanism for regulation of the phage packaging machine and other complex molecular machines.

Joint mice migration into the deep digital flexor tendon sheath in dogs. Clinical cases and anatomical study.

PubMed

Post, C; Guerrero, T; Ohlerth, S; Hässig, M; Voss, K; Montavon, P M

2008-01-01

This study describes the appearance of 'joint mice' in the sheath of the deep digital flexor muscle tendon (DDFT) due to osteochondritis dissecans (OCD) lesions in the talocrural joint of 12 dogs. Surgical excision of all free fragments in the DDFT sheath was performed in five dogs, and their clinical progression was documented. The excision of free fragments from the DDFT sheath, but not arthro-tomy, proved clinically beneficial despite the presence of degenerative joint disease. The anatomical communication between the talocrural joint and the DDFT sheath and its dimensions are further illustrated with the use of contrast media and dissection of cadaver limbs.

Double copper sheath multiconductor instrumentation cable is durable and easily installed in high thermal or nuclear radiation area

NASA Technical Reports Server (NTRS)

Mc Crae, A. W., Jr.

1967-01-01

Multiconductor instrumentation cable in which the conducting wires are routed through two concentric copper tube sheaths, employing a compressed insulator between the conductors and between the inner and outer sheaths, is durable and easily installed in high thermal or nuclear radiation area. The double sheath is a barrier against moisture, abrasion, and vibration.

Limited CD4+ T cell proliferation leads to preservation of CD4+ T cell counts in SIV-infected sooty mangabeys

PubMed Central

Chan, Ming Liang; Petravic, Janka; Ortiz, Alexandra M.; Engram, Jessica; Paiardini, Mirko; Cromer, Deborah; Silvestri, Guido; Davenport, Miles P.

2010-01-01

Human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV) infections result in chronic virus replication and progressive depletion of CD4+ T cells, leading to immunodeficiency and death. In contrast, ‘natural hosts’ of SIV experience persistent infection with high virus replication but no severe CD4+ T cell depletion, and remain AIDS-free. One important difference between pathogenic and non-pathogenic infections is the level of activation and proliferation of CD4+ T cells. We analysed the relationship between CD4+ T cell number and proliferation in HIV, pathogenic SIV in macaques, and non-pathogenic SIV in sooty mangabeys (SMs) and mandrills. We found that CD4+ T cell proliferation was negatively correlated with CD4+ T cell number, suggesting that animals respond to the loss of CD4+ T cells by increasing the proliferation of remaining cells. However, the level of proliferation seen in pathogenic infections (SIV in rhesus macaques and HIV) was much greater than in non-pathogenic infections (SMs and mandrills). We then used a modelling approach to understand how the host proliferative response to CD4+ T cell depletion may impact the outcome of infection. This modelling demonstrates that the rapid proliferation of CD4+ T cells in humans and macaques associated with low CD4+ T cell levels can act to ‘fuel the fire’ of infection by providing more proliferating cells for infection. Natural host species, on the other hand, have limited proliferation of CD4+ T cells at low CD4+ T cell levels, which allows them to restrict the number of proliferating cells susceptible to infection. PMID:20591864

Methylation-based classification of benign and malignant peripheral nerve sheath tumors.

PubMed

Röhrich, Manuel; Koelsche, Christian; Schrimpf, Daniel; Capper, David; Sahm, Felix; Kratz, Annekathrin; Reuss, Jana; Hovestadt, Volker; Jones, David T W; Bewerunge-Hudler, Melanie; Becker, Albert; Weis, Joachim; Mawrin, Christian; Mittelbronn, Michel; Perry, Arie; Mautner, Victor-Felix; Mechtersheimer, Gunhild; Hartmann, Christian; Okuducu, Ali Fuat; Arp, Mirko; Seiz-Rosenhagen, Marcel; Hänggi, Daniel; Heim, Stefanie; Paulus, Werner; Schittenhelm, Jens; Ahmadi, Rezvan; Herold-Mende, Christel; Unterberg, Andreas; Pfister, Stefan M; von Deimling, Andreas; Reuss, David E

2016-06-01

The vast majority of peripheral nerve sheath tumors derive from the Schwann cell lineage and comprise diverse histological entities ranging from benign schwannomas and neurofibromas to high-grade malignant peripheral nerve sheath tumors (MPNST), each with several variants. There is increasing evidence for methylation profiling being able to delineate biologically relevant tumor groups even within the same cellular lineage. Therefore, we used DNA methylation arrays for methylome- and chromosomal profile-based characterization of 171 peripheral nerve sheath tumors. We analyzed 28 conventional high-grade MPNST, three malignant Triton tumors, six low-grade MPNST, four epithelioid MPNST, 33 neurofibromas (15 dermal, 8 intraneural, 10 plexiform), six atypical neurofibromas, 43 schwannomas (including 5 NF2 and 5 schwannomatosis associated cases), 11 cellular schwannomas, 10 melanotic schwannomas, 7 neurofibroma/schwannoma hybrid tumors, 10 nerve sheath myxomas and 10 ganglioneuromas. Schwannomas formed different epigenomic subgroups including a vestibular schwannoma subgroup. Cellular schwannomas were not distinct from conventional schwannomas. Nerve sheath myxomas and neurofibroma/schwannoma hybrid tumors were most similar to schwannomas. Dermal, intraneural and plexiform neurofibromas as well as ganglioneuromas all showed distinct methylation profiles. Atypical neurofibromas and low-grade MPNST were indistinguishable with a common methylation profile and frequent losses of CDKN2A. Epigenomic analysis finds two groups of conventional high-grade MPNST sharing a frequent loss of neurofibromin. The larger of the two groups shows an additional loss of trimethylation of histone H3 at lysine 27 (H3K27me3). The smaller one retains H3K27me3 and is found in spinal locations. Sporadic MPNST with retained neurofibromin expression did not form an epigenetic group and most cases could be reclassified as cellular schwannomas or soft tissue sarcomas. Widespread immunohistochemical loss

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

PubMed

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 < 0.05) and incisional hernia (18% vs, 30%; p < 0.05) were significantly lower after rectus sheath relaxation incisions compared to conventional mass closure. Closure of the midline laparotomy wound in 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.

Constrained sheath optics for high thrust density, low specific impulse ion thrusters

NASA Technical Reports Server (NTRS)

Wilbur, Paul J.; Han, Jian-Zhang

1987-01-01

The results of an experimental study showing that a contoured, fine wire mesh attached to the screen grid can be used to control the divergence characteristics of ion beamlets produced at low net-to-total accelerating voltage ratios are presented. The influence of free and constrained-sheath optics systems on beamlet divergence characteristics are found to be similar in the operating regime investigated, but it was found that constrained-sheath optics systems can be operated at higher perveance levels than free-sheath ones. The concept of a fine wire interference probe that can be used to study ion beamlet focusing behavior is introduced. This probe is used to demonstrate beamlet focusing to a diameter about one hundreth of the screen grid extraction aperture diameter. Additional testing is suggested to define an optimally contoured mesh that could yield well focused beamlets at net-to-total accelerating voltage ratios below about 0.1.

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

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

Shaikh, Zubair; Bhaskar, Ankush; Raghav, Anil, E-mail: raghavanil1984@gmail.com

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 ofmore » 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.« less

Rectus sheath haematoma following exercise testing: a case report

PubMed Central

2009-01-01

Introduction Exercise testing is a safe diagnostic procedure which is widely used in the evaluation of patients suspected of having coronary heart disease or for the assessment of the prognosis in patients with established disease. Its complications are mainly cardiac disorders. Here, we report a rectus sheath haematoma as a complication of this procedure in a patient with acute coronary syndrome. To our knowledge, this is the first case report of rectus sheath haematoma in association with exercise testing. Case presentation A 72-year-old Caucasian woman was admitted for acute coronary syndrome. She received conservative treatment including low molecular weight heparin and anti-platelet agents. On the fifth day of her hospital stay, she underwent an exercise test, where no ischaemic response occurred. Several hours later, she experienced pain in the left side of her abdomen. Subsequent investigations revealed a rectus sheath haematoma. The patient underwent surgical haematoma evacuation. A few days later, re-operation was performed for recurrent bleeding in the abdominal wall. The patient had several characteristics known to increase the risk of bleeding during treatment for acute coronary syndrome. Conclusion Awareness of this possible consequence of exercise testing is important for preventing and treating it correctly. For prevention, an assessment of the bleeding risk of the individual patient is necessary before the test, and excessive anticoagulation must be avoided. PMID:20338023

Investigation of plasma-sheath resonances in low pressure discharges

NASA Astrophysics Data System (ADS)

Naggary, Schabnam; Kemaneci, Efe; Brinkmann, Ralf Peter; Megahed, Mustafa

2016-09-01

Plasma sheath resonances (PSR) arise from a periodic exchange between the kinetic electron energy in the plasma bulk and the electric field energy in the sheath and can easily be excited by the sheath-generated harmonics of the applied RF. In this contribution, we employ a series of models to obtain a well-defined description of these phenomena. In the first part, we use a global model to study the influence of the nonlinear charge-voltage characteristics on the electron dynamics. However, the global model is restricted to the assumption of spatially constant potential at each driven and grounded electrode and thus delivers only the fundamental mode of the current. In order to remedy the deficiency, we introduce a spatially resolved model for arbitrary reactor geometries with no assumptions on the homogeneity of the plasma. An exact evaluation of the analytical solution is realized on the assumption of a cylinderical plasma reactor geometry with uniform conductance. Furthermore, the spatially resolved model is capable of being utilized for a more realistic CCP reactor geometry and non homogeneous plasma provided the conductance distribution is known. For this purpose, we use the CFD-ACE+ tool. The results show that the proposed multi-mode model provides a significant improvement. The authors gratefully acknowledge the financial support by the ESI Group and the SFB- TR 87.

Prevention and Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

DTIC Science & Technology

2016-04-01

Page 1 AWARD NUMBER: W81XWH-14-1-0073 TITLE: Prevention and Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral...COVERED 04/01/2015 to 03/31/2016 4. TITLE AND SUBTITLE Prevention and Treatment of Neurofibromatosis Type 1- 5a. CONTRACT NUMBER W81XWH-14-1-0073...ABSTRACT The most common cause of death in Neurofibromatosis Type 1 (NF1) patients is malignant peripheral nerve sheath tumor (MPNST). MPNSTs are

The Ionospheric Impact of an ICME-Driven Sheath Region Over Indian and American Sectors in the Absence of a Typical Geomagnetic Storm

NASA Astrophysics Data System (ADS)

Rout, Diptiranjan; Chakrabarty, D.; Sarkhel, S.; Sekar, R.; Fejer, B. G.; Reeves, G. D.; Kulkarni, Atul S.; Aponte, Nestor; Sulzer, Mike; Mathews, John D.; Kerr, Robert B.; Noto, John

2018-05-01

On 13 April 2013, the ACE spacecraft detected arrival of an interplanetary shock at 2250 UT, which is followed by the passage of the sheath region of an interplanetary coronal mass ejection (ICME) for a prolonged (18-hr) period. The polarity of interplanetary magnetic field Bz was northward inside the magnetic cloud region of the ICME. The ring current (SYM-H) index did not go below -7 nT during this event suggesting the absence of a typical geomagnetic storm. The responses of the global ionospheric electric field associated with the passage of the ICME sheath region have been investigated using incoherent scatter radar measurements of Jicamarca and Arecibo (postmidnight sector) along with the variations of equatorial electrojet strength over India (day sector). It is found that westward and eastward prompt penetration (PP) electric fields affected ionosphere over Jicamarca/Arecibo and Indian sectors, respectively, during 0545-0800 UT. The polarities of the PP electric field perturbations over the day/night sectors are consistent with model predictions. In fact, DP2-type electric field perturbations with ˜40-min periodicity are found to affect the ionosphere over both the sectors for about 2.25 hr during the passage of the ICME sheath region. This result shows that SYM-H index may not capture the full geoeffectivenss of the ICME sheath-driven storms and suggests that the PP electric field perturbations should be evaluated for geoeffectiveness of ICME when the polarity of interplanetary magnetic field Bz is northward inside the magnetic cloud region of the ICME.

Identification of chromosomal locations associated with tail biting and being a victim of tail-biting behaviour in the domestic pig (Sus scrofa domesticus).

PubMed

Wilson, Kaitlin; Zanella, Ricardo; Ventura, Carlos; Johansen, Hanne Lind; Framstad, Tore; Janczak, Andrew; Zanella, Adroaldo J; Neibergs, Holly Louise

2012-11-01

The objective of this study was to identify loci associated with tail biting or being a victim of tail biting in Norwegian crossbred pigs using a genome-wide association study with PLINK case-control analysis. DNA was extracted from hair or blood samples collected from 98 trios of crossbred pigs located across Norway. Each trio came from the same pen and consisted of one pig observed to initiate tail biting, one pig which was the victim of tail biting and a control pig which was not involved in either behaviour. DNA was genotyped using the Illumina PorcineSNP60 BeadChip whole-genome single-nucleotide polymorphism (SNP) assay. After quality assurance filtering, 53,952 SNPs remained comprising 74 animals (37 pairs) for the tail biter versus control comparison and 53,419 SNPs remained comprising 80 animals (40 pairs) for the victim of tail biting versus control comparison. An association with being a tail biter was observed on Sus scrofa chromosome 16 (SSC16; p = 1.6 × 10(-5)) and an unassigned chromosome (p = 3.9 × 10(-5)). An association with being the victim of tail biting was observed on Sus scrofa chromosomes 1 (SSC1; p = 4.7 × 10(-5)), 9 (SSC9; p = 3.9 × 10(-5)), 18 (SSC18; p = 7 × 10(-5) for 9,602,511 bp, p = 3.4 × 10(-5) for 9,653,881 bp and p = 5.3 × 10(-5) for 29,577,783 bp) and an unassigned chromosome (p = 6.1 × 10(-5)). An r(2) = 0.96 and a D' = 1 between the two SNPs at 9 Mb on SSC18 indicated extremely high linkage disequilibrium, suggesting that these two markers represent a single locus. These results provide evidence of a moderate genetic association between the propensity to participate in tail-biting behaviour and the likelihood of becoming a victim of this behaviour.

Consequences of C4 differentiation for chloroplast membrane proteomes in maize mesophyll and bundle sheath cells.

PubMed

Majeran, Wojciech; Zybailov, Boris; Ytterberg, A Jimmy; Dunsmore, Jason; Sun, Qi; van Wijk, Klaas J

2008-09-01

Chloroplasts of maize leaves differentiate into specific bundle sheath (BS) and mesophyll (M) types to accommodate C(4) photosynthesis. Chloroplasts contain thylakoid and envelope membranes that contain the photosynthetic machineries and transporters but also proteins involved in e.g. protein homeostasis. These chloroplast membranes must be specialized within each cell type to accommodate C(4) photosynthesis and regulate metabolic fluxes and activities. This quantitative study determined the differentiated state of BS and M chloroplast thylakoid and envelope membrane proteomes and their oligomeric states using innovative gel-based and mass spectrometry-based protein quantifications. This included native gels, iTRAQ, and label-free quantification using an LTQ-Orbitrap. Subunits of Photosystems I and II, the cytochrome b(6)f, and ATP synthase complexes showed average BS/M accumulation ratios of 1.6, 0.45, 1.0, and 1.33, respectively, whereas ratios for the light-harvesting complex I and II families were 1.72 and 0.68, respectively. A 1000-kDa BS-specific NAD(P)H dehydrogenase complex with associated proteins of unknown function containing more than 15 proteins was observed; we speculate that this novel complex possibly functions in inorganic carbon concentration when carboxylation rates by ribulose-bisphosphate carboxylase/oxygenase are lower than decarboxylation rates by malic enzyme. Differential accumulation of thylakoid proteases (Egy and DegP), state transition kinases (STN7,8), and Photosystem I and II assembly factors was observed, suggesting that cell-specific photosynthetic electron transport depends on post-translational regulatory mechanisms. BS/M ratios for inner envelope transporters phosphoenolpyruvate/P(i) translocator, Dit1, Dit2, and Mex1 were determined and reflect metabolic fluxes in carbon metabolism. A wide variety of hundreds of other proteins showed differential BS/M accumulation. Mass spectral information and functional annotations are

The Child-Langmuir laws and cathode sheath in the N2O

NASA Astrophysics Data System (ADS)

Lisovskiy, Valeriy; Artushenko, Ekaterina; Yegorenkov, Vladimir

2013-09-01

It is established which of the Child-Langmuir collisional laws are most appropriate for describing the cathode sheath in the N2O. At low pressure p < 0 . 3 Torr the Child-Langmuir law version relating to the constant ion mobility. At p > 0 . 75 Torr one has to employ the law version for which it is assumed that ion mean free path within the cathode sheath is constant. In the intermediate pressure range 0 . 3 < p < 0 . 75 Torr neither of the Child-Langmuir law versions gives a correct description of the cathode sheath in the N2O. The ratio of the normal current density to the gas pressure squared J /p2 , the normal voltage drop and the cathode sheath thickness are determined. For the stainless steel cathode they equals to U = 364 V and pd = 2 . 5 Torr .mm. At large N2O pressure the above ratio remains constant and it amounts to J /p2 = 0.44 mA/(cm .Torr)2 for any inter-electrode gap value we studied. On decreasing the N2O pressure the ratio J /p2 increases and for narrow gaps between electrodes it may approach several or even several tens mA/(cm .Torr)2. and Scientific Center of Physical Technologies, Svobody Sq.6, Kharkov, 61022, Ukraine.

Calculation of the radial electric field with RF sheath boundary conditions in divertor geometry

NASA Astrophysics Data System (ADS)

Gui, B.; Xia, T. Y.; Xu, X. Q.; Myra, J. R.; Xiao, X. T.

2018-02-01

The equilibrium electric field that results from an imposed DC bias potential, such as that driven by a radio frequency (RF) sheath, is calculated using a new minimal two-field model in the BOUT++ framework. Biasing, using an RF-modified sheath boundary condition, is applied to an axisymmetric limiter, and a thermal sheath boundary is applied to the divertor plates. The penetration of the bias potential into the plasma is studied with a minimal self-consistent model that includes the physics of vorticity (charge balance), ion polarization currents, force balance with E× B , ion diamagnetic flow (ion pressure gradient) and parallel electron charge loss to the thermal and biased sheaths. It is found that a positive radial electric field forms in the scrape-off layer and it smoothly connects across the separatrix to the force-balanced radial electric field in the closed flux surface region. The results are in qualitative agreement with the experiments. Plasma convection related to the E× B net flow in front of the limiter is also obtained from the calculation.

Estimation of sheath potentials in front of ASDEX upgrade ICRF antenna with SSWICH asymptotic code

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

Křivská, A., E-mail: alena.krivska@rma.ac.be; Bobkov, V.; Jacquot, J.

Multi-megawatt Ion Cyclotron Range of Frequencies (ICRF) heating became problematic in ASDEX Upgrade (AUG) tokamak after coating of ICRF antenna limiters and other plasma facing components by tungsten. Strong impurity influx was indeed produced at levels of injected power markedly lower than in the previous experiments. It is assumed that the impurity production is mainly driven by parallel component of Radio-Frequency (RF) antenna electric near-field E// that is rectified in sheaths. In this contribution we estimate poloidal distribution of sheath Direct Current (DC) potential in front of the ICRF antenna and simulate its relative variations over the parametric scans performedmore » during experiments, trying to reproduce some of the experimental observations. In addition, relative comparison between two types of AUG ICRF antenna configurations, used for experiments in 2014, has been performed. For this purpose we use the Torino Polytechnic Ion Cyclotron Antenna (TOPICA) code and asymptotic version of the Self-consistent Sheaths and Waves for Ion Cyclotron Heating (SSWICH) code. Further, we investigate correlation between amplitudes of the calculated oscillating sheath voltages and the E// fields computed at the lateral side of the antenna box, in relation with a heuristic antenna design strategy at IPP Garching to mitigate RF sheaths.« less

Formation of stable inverse sheath in ion–ion plasma by strong negative ion emission

NASA Astrophysics Data System (ADS)

Zhang, Zhe; Wu, Bang; Yang, Shali; Zhang, Ya; Chen, Dezhi; Fan, Mingwu; Jiang, Wei

2018-06-01

The effect of strong charged particle emission on plasma–wall interactions is a classical, yet unresolved question in plasma physics. Previous studies on secondary electron emission have shown that with different emission coefficients, there are classical, space-charge-limited, and inverse sheaths. In this letter, we demonstrate that a stable ion–ion inverse sheath and ion–ion plasma are formed with strong surface emission of negative ions. The continuous space-charge-limited to inverse ion–ion sheath transition is observed, and the plasma near the surface consequently transforms into pure ion–ion plasma. The results may explain the long-puzzled experimental observation that the density of negative ions depends on only charge not mass in negative ion sources.

Element flows associated with marine shore mine tailings deposits.

PubMed

Dold, Bernhard

2006-02-01

From 1938 until 1975, flotation tailings from the Potrerillos--El Salvador mining district (porphyry copper deposits) were discharged into the El Salado valley and transported in suspension to the sea at Chaliaral Bay, Atacama Desert, northern Chile. Over 220 Mt of tailings, averaging 0.8 +/- 0.25 wt % of pyrite, were deposited into the bay, resulting in over a 1 kilometer seaward displacement of the shoreline and an estimated 10-15 m thick tailings accumulation covering a approximately 4 km2 surface area. The Chaniaral case was classified by the United Nations Environmental Programme (UNEP) in 1983 as one of the most serious cases of marine contamination in the Pacific area. Since 1975, the tailings have been exposed to oxidation, resulting in a 70-188 cm thick low-pH (2.6-4) oxidation zone at the top with liberation of divalent metal cations, such as Cu2+, Ni2+, and Zn2+ (up to 2265 mg/L, 18.1 mg/L, and 20.3 mg/ L, respectively). Evaporation-induced transport capillarity led to metal enrichment atthe tailings surface (e.g. up to 2.4% Cu) in the form of secondary chlorides and/or sulfates (dominated by eriochalcite [CuCl.H2O] and halite). These, mainly water-soluble, secondary minerals were exposed to eolian transport in the direction of the Village of Chañaral by the predominant W-SW winds. Two element-flow directions (toward the tailings surface, via capillarity, and toward the sea) and two element groups with different geochemical behaviors (cations such as Cu, Zn, Ni, and oxyanions such as As and Mo) could be distinguished. It can be postulated, that the sea is mainly affected by the following: As, Mo, Cu, and Zn contamination, which were liberated from the oxidation zone from the tailings and mobilized through the tidal cycle, and by Cu and Zn from the subsurface waters flowing in the El Salado valley (up to 19 mg/L and 12 mg/L Zn, respectively), transported as chloro complexes at neutral pH.

Branched Lateral Tail Fiber Organization in T5-Like Bacteriophages DT57C and DT571/2 is Revealed by Genetic and Functional Analysis.

PubMed

Golomidova, Alla K; Kulikov, Eugene E; Prokhorov, Nikolai S; Guerrero-Ferreira, Ricardo С; Knirel, Yuriy A; Kostryukova, Elena S; Tarasyan, Karina K; Letarov, Andrey V

2016-01-21

The T5-like siphoviruses DT57C and DT571/2, isolated from horse feces, are very closely related to each other, and most of their structural proteins are also nearly identical to T5 phage. Their LTFs (L-shaped tail fibers), however, are composed of two proteins, LtfA and LtfB, instead of the single Ltf of bacteriophage T5. In silico and mutant analysis suggests a possible branched structure of DT57C and DT571/2 LTFs, where the LtfB protein is connected to the phage tail via the LtfA protein and with both proteins carrying receptor recognition domains. Such adhesin arrangement has not been previously recognized in siphoviruses. The LtfA proteins of our phages are found to recognize different host O-antigen types: E. coli O22-like for DT57C phage and E. coli O87 for DT571/2. LtfB proteins are identical in both phages and recognize another host receptor, most probably lipopolysaccharide (LPS) of E. coli O81 type. In these two bacteriophages, LTF function is essential to penetrate the shield of the host's O-antigens. We also demonstrate that LTF-mediated adsorption becomes superfluous when the non-specific cell protection by O-antigen is missing, allowing the phages to bind directly to their common secondary receptor, the outer membrane protein BtuB. The LTF independent adsorption was also demonstrated on an O22-like host mutant missing O-antigen O-acetylation, thus showing the biological value of this O-antigen modification for cell protection against phages.

Potential application of X-ray communication through a plasma sheath encountered during spacecraft reentry into earth's atmosphere

NASA Astrophysics Data System (ADS)

Li, Huan; Tang, Xiaobin; Hang, Shuang; Liu, Yunpeng; Chen, Da

2017-03-01

Rapid progress in exploiting X-ray science has fueled its potential application in communication networks as a carrier wave for transmitting information through a plasma sheath during spacecraft reentry into earth's atmosphere. In this study, we addressed the physical transmission process of X-rays in the reentry plasma sheath and near-earth space theoretically. The interactions between the X-rays and reentry plasma sheath were investigated through the theoretical Wentzel-Kramers-Brillouin method, and the Monte Carlo simulation was employed to explore the transmission properties of X-rays in the near-earth space. The simulation results indicated that X-ray transmission was not influenced by the reentry plasma sheath compared with regular RF signals, and adopting various X-ray energies according to different spacecraft reentry altitudes is imperative when using X-ray uplink communication especially in the near-earth space. Additionally, the performance of the X-ray communication system was evaluated by applying the additive white Gaussian noise, Rayleigh fading channel, and plasma sheath channel. The Doppler shift, as a result of spacecraft velocity changes, was also calculated through the Matlab Simulink simulation, and various plasma sheath environments have no significant influence on X-ray communication owing to its exceedingly high carrier frequency.

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

NASA Astrophysics Data System (ADS)

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

The effects of secondary emission on the sheath structure in an electrostatic dusty plasma containing energetic electrons and charged nanoparticles

NASA Astrophysics Data System (ADS)

Jalilpour, P.; Foroutan, G.

2018-03-01

Multi-fluid numerical simulations are utilized to explore the effects of secondary emission by nanosize dust particles on the structure of a dusty plasma sheath in the presence of a beam of fast, mono-energetic electrons. It was found that the sheath dynamics depends strongly on the magnitude of the secondary emission yield δm. For δm smaller than unity, the secondary emission is weak, and the sheath width always increases with increasing beam flux, such that it experiences a sharp transition from the regime of thin sheath to the regime of thick sheath, at a given beam flux. For δm larger than unity, the secondary emission dominates the dust dynamics, and the sheath width always decreases with increasing beam flux. The sheath thickness decreases very quickly with the secondary emission yield, but increases with Em, the characteristic energy corresponding to the maximum secondary emission. As δm is increased, the absolute dust charge and hence the accelerating ion drag force are reduced. Then, the dust is decelerated and as a result the dust number density is enhanced. Increasing the dust radius and/or the dust number density leads to an enhanced secondary emission effect and thus to a narrower sheath width.

Deep crustal deformation by sheath folding in the Adirondack Mountains, USA

NASA Technical Reports Server (NTRS)

Mclelland, J. M.

1988-01-01

As described by McLelland and Isachsen, the southern half of the Adirondacks are underlain by major isoclinal (F sub 1) and open-upright (F sub 2) folds whose axes are parallel, trend approximately E-W, and plunge gently about the horizontal. These large structures are themselves folded by open upright folds trending NNE (F sub 3). It is pointed out that elongation lineations in these rocks are parallel to X of the finite strain ellipsoid developed during progressive rotational strain. The parallelism between F sub 1 and F sub 2 fold axes and elongation lineations led to the hypothesis that progressive rotational strain, with a west-directed tectonic transport, rotated earlier F sub 1-folds into parallelism with the evolving elongation lineation. Rotation is accomplished by ductile, passive flow of F sub 1-axes into extremely arcuate, E-W hinges. In order to test these hypotheses a number of large folds were mapped in the eastern Adirondacks. Other evidence supporting the existence of sheath folds in the Adirondacks is the presence, on a map scale, of synforms whose limbs pass through the vertical and into antiforms. This type of outcrop pattern is best explained by intersecting a horizontal plane with the double curvature of sheath folds. It is proposed that sheath folding is a common response of hot, ductile rocks to rotational strain at deep crustal levels. The recognition of sheath folds in the Adirondacks reconciles the E-W orientation of fold axes with an E-W elongation lineation.

Retroperitoneal and rectus sheath hematomas.

PubMed

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.

An improved implementable process for the synthesis of zeolite 4A from bauxite tailings and its Cr3+ removal capacity

NASA Astrophysics Data System (ADS)

Lei, Peng-cheng; Shen, Xian-jiang; Li, Yang; Guo, Min; Zhang, Mei

2016-07-01

A simple and practical method for the synthesis of zeolite 4A from bauxite tailings is presented in this paper. Systematic investigations were carried out regarding the capacity of zeolite 4A to remove Cr(III) from aqueous solutions with relatively low initial concentrations of Cr(III) (5-100 mg·L-1). It is found that the new method is extremely cost-effective and can significantly contribute in decreasing environmental pollution caused by the dumping of bauxite tailings. The Cr(III) removal capacity highly depends on the initial pH value and concentration of Cr(III) in the solution. The maximum removal capacity of Cr(III) was evaluated to be 85.1 mg·g-1 for zeolite 4A, measured at an initial pH value of 4 and an initial Cr(III) concentration of 5 mg·L-1. This approach enables a higher removal capacity at lower concentrations of Cr(III), which is a clear advantage over the chemical precipitation method. The removal mechanism of Cr(III) by zeolite 4A was examined. The results suggest that both ion exchange and the surface adsorption-crystallization reaction are critical steps. These two steps collectively resulted in the high removal capacity of zeolite 4A to remove Cr(III).

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

NASA Astrophysics Data System (ADS)

Bai, Bowen; Liu, Yanming; Lin, Xiaofang; Li, Xiaoping

2018-03-01

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.

A post-processing method to simulate the generalized RF sheath boundary condition